PIC18F26/45/46Q10
28/40-Pin, Low-Power, High-Performance Microcontrollers
Description
PIC18F26/45/46Q10 microcontrollers feature analog, core independent, and communication peripherals
for a wide range of general purpose and low-power applications. These 28/40/44-pin devices are
equipped with a 10-bit ADC with Computation (ADC2) automating Capacitive Voltage Divider (CVD)
techniques for advanced touch sensing, averaging, filtering, oversampling and performing automatic
threshold comparisons. They also offer a set of core independent peripherals such as Complementary
Waveform Generator (CWG), Windowed Watchdog Timer (WWDT), Cyclic Redundancy Check (CRC)/
Memory Scan, Zero-Cross Detect (ZCD), Configurable Logic Cell (CLC), and Peripheral Pin Select
(PPS), providing increased design flexibility and lower system cost.
Core Features
C Compiler Optimized RISC Architecture
Operating Speed:
DC – 64 MHz clock input over the full VDD range
62.5 ns minimum instruction cycle
Programmable 2-Level Interrupt Priority
31-Level Deep Hardware Stack
Three 8-Bit Timers (TMR2/4/6) with Hardware Limit Timer (HLT)
Four 16-Bit Timers (TMR0/1/3/5)
Low-Current Power-on Reset (POR)
Power-up Timer (PWRT)
Brown-out Reset (BOR)
Low-Power BOR (LPBOR) Option
Windowed Watchdog Timer (WWDT):
Watchdog Reset on too long or too short interval between watchdog clear events
Variable prescaler selection
Variable window size selection
All sources configurable in hardware or software
Memory
Up to 64K Bytes Program Flash Memory
Up to 3615 Bytes Data SRAM Memory
Up to 1024 Bytes Data EEPROM
Programmable Code Protection
© 2019 Microchip Technology Inc. Preliminary Datasheet DS40001996C-page 1
Direct, Indirect and Relative Addressing modes
Operating Characteristics
Operating Voltage Range:
1.8V to 5.5V
Temperature Range:
Industrial: -40°C to 85°C
Extended: -40°C to 125°C
Power-Saving Operation Modes
Doze: CPU and Peripherals Running at Different Cycle Rates (typically CPU is lower)
Idle: CPU Halted While Peripherals Operate
Sleep: Lowest Power Consumption
Peripheral Module Disable (PMD):
Ability to selectively disable hardware module to minimize active power consumption of unused
peripherals
Extreme Low-Power mode (XLP)
Sleep: 500 nA typical @ 1.8V
Sleep and Watchdog Timer: 900 nA typical @ 1.8V
Digital Peripherals
Configurable Logic Cell (CLC):
Integrated combinational and sequential logic
Complementary Waveform Generator (CWG):
Rising and falling edge dead-band control
Full-bridge, half-bridge, 1-channel drive
Multiple signal sources
Capture/Compare/PWM (CCP) modules:
Two CCPs
16-bit resolution for Capture/Compare modes
10-bit resolution for PWM mode
10-Bit Pulse-Width Modulators (PWM):
Two 10-bit PWMs
Serial Communications:
Two Enhanced USART (EUSART) with Auto-Baud Detect, Auto-wake-up on Start.
RS-232, RS-485, LIN compatible
SPI
I2C, SMBus and PMBus compatible
Up to 35 I/O Pins and One Input Pin:
Individually programmable pull-ups
Slew rate control
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 2
Interrupt-on-change on all pins
Input level selection control
Programmable CRC with Memory Scan:
Reliable data/program memory monitoring for Fail-Safe operation (e.g., Class B)
Calculate CRC over any portion of Flash or EEPROM
High-speed or background operation
Hardware Limit Timer (TMR2/4/6+HLT):
Hardware monitoring and Fault detection
Peripheral Pin Select (PPS):
Enables pin mapping of digital I/O
Data Signal Modulator (DSM)
Analog Peripherals
10-Bit Analog-to-Digital Converter with Computation (ADC2):
35 external channels
Conversion available during Sleep
Four internal analog channels
Internal and external trigger options
Automated math functions on input signals:
Averaging, filter calculations, oversampling and threshold comparison
8-bit hardware acquisition timer
Hardware Capacitive Voltage Divider (CVD) Support:
8-bit precharge timer
Adjustable Sample-and-Hold capacitor array
Guard ring digital output drive
Zero-Cross Detect (ZCD):
Detect when AC signal on pin crosses ground
5-Bit Digital-to-Analog Converter (DAC):
Output available externally
Programmable 5-bit voltage (% of VDD,[VREF+ - VREF-], FVR)
Internal connections to comparators and ADC
Two Comparators (CMP):
Four external inputs
External output via PPS
Fixed Voltage Reference (FVR) Module:
1.024V, 2.048V and 4.096V output levels
Two buffered outputs: One for DAC/CMP and one for ADC
Clocking Structure
High-Precision Internal Oscillator Block (HFINTOSC):
Selectable frequencies up to 64 MHz
±1% at calibration
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 3
32 kHz Low-Power Internal Oscillator (LFINTOSC)
External 32 kHz Crystal Oscillator (SOSC)
External High-frequency Oscillator Block:
Three crystal/resonator modes
Digital Clock Input mode
4x PLL with external sources
Fail-Safe Clock Monitor:
Allows for safe shutdown if external clock stops
Oscillator Start-up Timer (OST)
Programming/Debug Features
In-Circuit Serial Programming (ICSP) via Two Pins
In-Circuit Debug (ICD) with Three Breakpoints via Two Pins
Debug Integrated On-Chip
PIC18F26/45/46Q10 Family Types
Table 1.  Devices included in this data sheet
Device
Program Memory Flash
(bytes)
Data SRAM
(bytes)(2)
Data EEPROM
(bytes)
I/O Pins
16-bit Timers
Comparators
10-bit ADC2 with
Computation (ch)
5-bit DAC
Zero-Cross Detect
CCP/10-bit PWM
CWG
CLC
Low Voltage Detect (LVD)
8-bit TMR with HLT
Windowed Watchdog
Timer
CRC with Memory Scan
EUSART
I2C/SPI
PPS
Peripheral Module Disable
Temperature Indicator
Debug(1)
PIC18F26Q10 64k 3615 1024 25 4 2 24 1 1 2/2 1 8 1 3 Y Y 2 2 Y Y Y I
PIC18F45Q10 32k 2304 256 36 4 2 35 1 1 2/2 1 8 1 3 Y Y 2 2 Y Y Y I
PIC18F46Q10 64k 3615 1024 36 4 2 35 1 1 2/2 1 8 1 3 Y Y 2 2 Y Y Y I
Note: 
1. Debugging Methods: (I) – Integrated on-chip.
2. SRAM includes 256 bytes of SECTOR space which is not included in the data size displayed by MPLAB X.
Table 2. Devices not included in this data sheet
Device
Program Memory Flash
(bytes)
Data SRAM
(bytes)(2)
Data EEPROM
(bytes)
I/O Pins
16-bit Timers
Comparators
10-bit ADC2 with
Computation (ch)
5-bit DAC
Zero-Cross Detect
CCP/10-bit PWM
CWG
CLC
Low Voltage Detect (LVD)
8-bit TMR with HLT
Windowed Watchdog
Timer
CRC with Memory Scan
EUSART
I2C/SPI
PPS
Peripheral Module Disable
Temperature Indicator
Debug(1)
PIC18F24Q10 16k 1280 256 25 4 2 24 1 1 2/2 1 0 1 3 Y Y 1 1 Y Y Y I
PIC18F25Q10 32k 2304 256 25 4 2 24 1 1 2/2 1 0 1 3 Y Y 1 1 Y Y Y I
PIC18F27Q10 128k 3615 1024 25 4 2 24 1 1 2/2 1 8 1 3 Y Y 2 2 Y Y Y I
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 4
...........continued
Device
Program Memory Flash
(bytes)
Data SRAM
(bytes)(2)
Data EEPROM
(bytes)
I/O Pins
16-bit Timers
Comparators
10-bit ADC2 with
Computation (ch)
5-bit DAC
Zero-Cross Detect
CCP/10-bit PWM
CWG
CLC
Low Voltage Detect (LVD)
8-bit TMR with HLT
Windowed Watchdog
Timer
CRC with Memory Scan
EUSART
I2C/SPI
PPS
Peripheral Module Disable
Temperature Indicator
Debug(1)
PIC18F47Q10 128k 3615 1024 36 4 2 35 1 1 2/2 1 8 1 3 Y Y 2 2 Y Y Y I
Note: 
1. Debugging Methods: (I) – Integrated on-chip.
2. SRAM includes 256 bytes of SECTOR space which is not included in the data size displayed by MPLAB X.
Data Sheet Index:
1. DS40001945 Data Sheet, 28-Pin, 8-bit Flash Microcontrollers
2. DS40002043 Data Sheet, 28/40-Pin, 8-bit Flash Microcontrollers
Packages
Important:  For other small form-factor package availability and marking information, visit
http://www.microchip.com/packaging or contact your local Microchip sales office.
Packages SPDIP
(SP)
SOIC
(SO)
SSOP
(SS)
QFN
(ML)
(6x6x0.9)
VQFN
(STX)
(4x4x1)
TQFP
(PT)
PDIP
(P)
QFN
(MP)
(5x5x0.9)
PIC18F26Q10
PIC18F45Q10
PIC18F46Q10
Important:  Pin details are subject to change.
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 5
Pin Diagrams
Figure 1. 28-pin SPDIP, SSOP, SOIC
Filename: 00-000028A.vsd
Title: 28-pin DIP
Last Edit: 10/3/2018
First Used: N/A
Notes: Generic 28-pin dual in-line diagram
Rev. 00-000028A
10/3/2018
MCLR/VPP/RE3 28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
RA0
RA1
RA2
RA3
RA4
RA5
VSS
RA7
RA6
RC0
RC1
RC2
RC3 RC4
RC5
RC6
RC7
VSS
VDD
RB0
RB1
RB2
RB3
RB4
RB5
RB6/ICSPCLK
RB7/ICSPDAT
Figure 2. 28-pin QFN VQFN
Rev. 00-000028B
6/23/2017
28 27
RB3
RB2
RC7
RB5
RB4
VSS
RB1
RB0
VDD
RB6/ICSPCLK
RB7/ICSPDAT
RE3/MCLR/VPP
RA0
RA1
26 25 24 23 22
8 9 10 11 12 13 14
15
16
17
18
19
20
21
7
6
5
4
3
2
1
RC5
RC6
RC4
RC3
RC2
RC1
RC0
RA2
RA3
RA6
RA7
RA4
RA5
VSS
Note:  It is recommended that the exposed bottom pad be connected to VSS, however it must not be the
only VSS connection to the device.
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 6
Figure 3. 40-pin PDIP
Filename: 00-000040A.vsd
Title: 40-pin DIP
Last Edit: 10/3/2018
First Used: N/A
Notes: Generic 40-pin dual in-line diagram
Rev. 00-000040A
10/3/2018
MCLR/VPP/RE3 40
39
38
37
36
35
34
33
32
31
30
29
28
27
14
13
12
11
10
9
8
7
6
5
4
3
2
1
RA0
RA1
RA2
RA3
RA4
RA5
VSS
RA7
RA6
RC0
RC1
RC2
RC3
RD4
RD5
RD6
RD7
VSS
VDD
RB0
RB1
RB2
RB3
RB4
RB5
RB6/ICSPCLK
RB7/ICSPDAT
15
16
17
18
19
20
26
25
24
23
22
21
RD0
RD1
VDD
RE0
RE1
RE2
RD2
RD3
RC4
RC5
RC6
RC7
Figure 4. 40-pin QFN
Filename: 00-000040B.vsd
Title: 40-pin QFN
Last Edit: 11/6/2017
First Used: N/A
Notes: Generic 40-pin QFN diagram
Rev. 00-000040B
11/6/2017
40 39
RC0
RA6
RE1
RE0
RA5
RA4
RC1
RC2
RC3
RD1
RD0
RE2
RA7
VSS
VDD
RD2
RD3
RC4
RC5
RC6
38 37 36 35 34 33 32 31
11 12 13 14 15 16 17 18 19 20
21
22
23
24
25
26
27
28
29
30
10
9
8
7
6
5
4
3
2
1
RA3
RA2
RA1
VPP/MCLR/RE3
RA0
ICSPDAT/RB7
ICSPCLK/RB6
RB5
RB4
RB3
RC7
RD4
VDD
RB0
RB1
RB2
VSS
RD5
RD6
RD7
Note:  It is recommended that the exposed bottom pad be connected to VSS, however it must not be the
only VSS connection to the device.
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 7
Figure 5. 44-pin TQFP
Filename: 00-000044A.vsd
Title: 44-pin TQFP
Last Edit: 11/6/2017
First Used: N/A
Notes: Generic 44-pin TQFP diagram
Rev. 00-000044A
11/6/2017
40 39
RA6
RA7
RE1
RE0
RA5
RA4
RC1
RC2
RC3
RD1
RD0
RE2
NC
VSS
VDD
RD2
RD3
RC4
RC5
RC6
38 37 36 35 34
33
32
31
12 13 14 15 16 17 18 19 20 21 22
23
24
25
26
27
28
29
30
10
9
8
7
6
5
4
3
2
1
RA3
RA2
RA1
VPP/MCLR/RE3
RA0
ICSPDAT/RB7
ICSPCLK/RB6
RB5
RB4
RB3
RC7
RD4
VDD
RB0
RB1
RB2
VSS
RD5
RD6
RD7
11
44 43 42 41
NC
NC
NC
RC0
Pin Allocation Tables
Table 3. 28-Pin Allocation Table
I/O(2)
28-Pin
SPDIP,
SOIC,
SSOP
28-Pin
(V)QFN A/D Reference Comparator Timers CCP CWG ZCD Interrupt EUSART DSM MSSP Pull-
up Basic
RA0 2 27 ANA0 C1IN0-
C2IN0-
IOCA0 Y
RA1 3 28 ANA1 C1IN1-
C2IN1-
IOCA1 Y
RA2 4 1 ANA2 DAC1OUT1
VREF- (DAC)
VREF- (ADC)
C1IN0+
C2IN0+
IOCA2 Y
RA3 5 2 ANA3 VREF+ (DAC)
VREF+ (ADC)
C1IN1+ IOCA3 MDCARL(1) Y
RA4 6 3 ANA4 T0CKI(1) IOCA4 MDCARH(1) Y
RA5 7 4 ANA5 IOCA5 MDSRC(1) SS1(1) Y
RA6 10 7 ANA6 IOCA6 Y CLKOUT
OSC2
RA7 9 6 ANA7 IOCA7 Y OSC1
CLKIN
RB0 21 18 ANB0 C2IN1+ CWG1(1) ZCDIN IOCB0
INT0(1)
SS2(1) Y
RB1 22 19 ANB1 C1IN3-
C2IN3-
IOCB1
INT1(1)
SCK2(1)
SCL2(3,4)
Y
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 8
...........continued
I/O(2)
28-Pin
SPDIP,
SOIC,
SSOP
28-Pin
(V)QFN A/D Reference Comparator Timers CCP CWG ZCD Interrupt EUSART DSM MSSP Pull-
up Basic
RB2 23 20 ANB2 IOCB2
INT2(1)
SDI2(1)
SDA2(3,4)
Y
RB3 24 21 ANB3 C1IN2-
C2IN2-
IOCB3 Y
RB4 25 22 ANB4 T5G(1) IOCB4 Y
RB5 26 23 ANB5 T1G(1) IOCB5 Y
RB6 27 24 ANB6 IOCB6 Y ICSPCLK
RB7 28 25 ANB7 DAC1OUT2 T6IN(1) IOCB7 Y ICSPDAT
RC0 11 8 ANC0 T1CKI(1)
T3CKI(1)
T3G(1)
IOCC0 Y SOSCO
RC1 12 9 ANC1 CCP2(1) IOCC1 Y SOSCIN
SOSCI
RC2 13 10 ANC2 T5CKI(1) CCP1(1) IOCC2 Y
RC3 14 11 ANC3 T2IN(1) IOCC3 SCK1(1)
SCL1(3,4)
Y
RC4 15 12 ANC4 IOCC4 SDI1(1)
SDA1(3,4)
Y
RC5 16 13 ANC5 T4IN(1) IOCC5 Y
RC6 17 14 ANC6 IOCC6 CK1(1,3) Y
RC7 18 15 ANC7 IOCC7 RX1/
DT1(1,3)
Y
RE3 1 26 IOCE3 Y Vpp/MCLR
VSS 19 16 VSS
VDD(5) 20 17 VDD
VSS 8 5 VSS
OUT(2) ADGRDA
ADGRDB
C1OUT
C2OUT
TMR0 CCP1
CCP2
PWM3
PWM4
CWG1A
CWG1B
CWG1C
CWG1D
TX1/
CK1(3)
DT1(3)
DSM SDO1
SCK1
Note: 
1. This is a PPS remappable input signal. The input function may be moved from the default location shown to one of several other PORTx pins. Refer to the
peripheral input selection table for details on which port pins may be used for this signal.
2. All output signals shown in this row are PPS remappable. These signals may be mapped to output onto one of several PORTx pin options as described in the
peripheral output selection table.
3. This is a bidirectional signal. For normal module operation, the firmware should map this signal to the same pin in both the PPS input and PPS output registers.
4. These pins are configured for I2C logic levels; The SCLx/SDAx signals may be assigned to any of these pins. PPS assignments to the other pins (e.g., RB1) will
operate, but input logic levels will be standard TTL/ST as selected by the INLVL register, instead of the I2C specific or SMBus input buffer thresholds.
5. A 0.1 uF bypass capacitor to VSS is required on the VDD pin.
Table 4.  40/44-Pin Allocation Table
I/O(2) 40-Pin
PDIP
40-
Pin
QFN
44-Pin
TQFP A/D Reference Comparator Timers CCP CWG ZCD Interrupt EUSART DSM MSSP Pull-
up Basic
RA0 2 17 19 ANA0 C1INO-
C2IN0-
IOCA0 Y
RA1 3 18 20 ANA1 C1IN1-
C2IN1-
IOCA1 Y
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 9
...........continued
I/O(2) 40-Pin
PDIP
40-
Pin
QFN
44-Pin
TQFP A/D Reference Comparator Timers CCP CWG ZCD Interrupt EUSART DSM MSSP Pull-
up Basic
RA2 4 19 21 ANA2 DAC1OUT1
VREF-
(DAC5)
VREF-
(ADC)
C1IN0+
C2IN0+
IOCA2 Y
RA3 5 20 22 ANA3 VREF+
(DAC5)
VREF+
(ADC)
C1IN1+ IOCA3 MDCARL(1) Y
RA4 6 21 23 ANA4 T0CKI(1) IOCA4 MDCARH(1) Y
RA5 7 22 24 ANA5 IOCA5 MDSRC(1) SS1(1) Y
RA6 14 29 31 ANA6 IOCA6 Y CLKOUT
OSC2
RA7 13 28 30 ANA7 IOCA7 Y OSC1
CLKIN
RB0 33 8 8 ANB0 C2IN1+ CWG1(1) ZCDIN IOCB0
INT0(1)
SS2(1) Y
RB1 34 9 9 ANB1 C1IN3-
C2IN3-
IOCB1
INT1(1)
SCK2(1)
SCL2(3,4)
Y
RB2 35 10 10 ANB2 IOCB2
INT2(1)
SDI2(1)
SDA2(3,4)
Y
RB3 36 11 11 ANB3 C1IN2-
C2IN2-
IOCB3 Y
RB4 37 12 14 ANB4 T5G(1) IOCB4 Y
RB5 38 13 15 ANB5 T1G(1) IOCB5 Y
RB6 39 14 16 ANB6 IOCB6 CK2(1,3) Y ICSPCLK
RB7 40 15 17 ANB7 DAC1OUT2 T6IN(1) IOCB7 RX2/
DT2(1,3)
Y ICSPDAT
RC0 15 30 32 ANC0 T1CKI(1)
T3CKI(1)
T3G(1)
IOCC0 Y SOSCO
RC1 16 31 35 ANC1 CCP2(1) IOCC1 Y SOSCIN
SOSCI
RC2 17 32 36 ANC2 T5CKI(1) CCP1(1) IOCC2 Y
RC3 18 33 37 ANC3 T2IN(1) IOCC3 SCK1(1)
SCL1(3,4)
Y
RC4 23 38 42 ANC4 IOCC4 SDI1(1)
SDA1(3,4)
RC5 24 39 43 ANC5 T4IN(1) IOCC5 Y
RC6 25 40 44 ANC6 IOCC6 CK1(1,3) Y
RC7 26 1 1 ANC7 IOCC7 RX1/
DT1(1,3)
Y
RD0 19 34 38 AND0 Y
RD1 20 35 39 AND1 Y
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 10
...........continued
I/O(2) 40-Pin
PDIP
40-
Pin
QFN
44-Pin
TQFP A/D Reference Comparator Timers CCP CWG ZCD Interrupt EUSART DSM MSSP Pull-
up Basic
RD2 21 36 40 AND2 Y
RD3 22 37 41 AND3 Y
RD4 27 2 2 AND4 Y
RD5 28 3 3 AND5 Y
RD6 29 4 4 AND6 Y
RD7 30 5 5 AND7 Y
RE0 8 23 25 ANE0 Y
RE1 9 24 26 ANE1 Y
RE2 10 25 27 ANE2 Y
RE3 1 16 18 IOCE3 Y Vpp/MCLR
VSS 12 6 6 VSS
VDD(5) 11 7 7 VDD
VDD(5) 32 26 28 VSS
VSS 31 27 29 VSS
OUT(2) ADGRDA
ADGRDB
C1OUT
C2OUT
TMR0 CCP1
CCP2
PWM3
PWM4
CWG1A
CWG1B
CWG1C
CWG1D
TX1/
CK1(3)
DT1(3)
TX2/
CK2(3)
DT2(3)
DSM SDO1
SCK1
SDO2
SCK2
Note: 
1. This is a PPS remappable input signal. The input function may be moved from the default location shown to one of several other PORTx pins. Refer to the
peripheral input selection table for details on which port pins may be used for this signal.
2. All output signals shown in this row are PPS remappable. These signals may be mapped to output onto one of several PORTx pin options as described in the
peripheral output selection table.
3. This is a bidirectional signal. For normal module operation, the firmware should map this signal to the same pin in both the PPS input and PPS output registers.
4. These pins are configured for I2C logic levels; The SCLx/SDAx signals may be assigned to any of these pins. PPS assignments to the other pins (e.g., RB1) will
operate, but input logic levels will be standard TTL/ST as selected by the INLVL register, instead of the I2C specific or SMBus input buffer thresholds.
5. A 0.1 uF bypass capacitor to VSS is required on all VDD pins.
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 11
Table of Contents
Description.......................................................................................................................1
Core Features..................................................................................................................1
Memory............................................................................................................................1
Operating Characteristics................................................................................................2
Power-Saving Operation Modes......................................................................................2
Digital Peripherals........................................................................................................... 2
Analog Peripherals.......................................................................................................... 3
Clocking Structure........................................................................................................... 3
Programming/Debug Features........................................................................................ 4
PIC18F26/45/46Q10 Family Types................................................................................. 4
Packages.........................................................................................................................5
Pin Diagrams...................................................................................................................6
Pin Allocation Tables....................................................................................................... 8
1. Device Overview......................................................................................................15
2. Guidelines for Getting Started with PIC18F26/45/46Q10 Microcontrollers............. 23
3. Device Configuration............................................................................................... 28
4. Oscillator Module (with Fail-Safe Clock Monitor).....................................................44
5. Reference Clock Output Module............................................................................. 66
6. Power-Saving Operation Modes..............................................................................72
7. (PMD) Peripheral Module Disable........................................................................... 81
8. Resets..................................................................................................................... 90
9. (WWDT) Windowed Watchdog Timer....................................................................104
10. Memory Organization............................................................................................ 116
11. (NVM) Nonvolatile Memory Control.......................................................................151
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 12
12. 8x8 Hardware Multiplier.........................................................................................180
13. (CRC) Cyclic Redundancy Check Module with Memory Scanner.........................185
14. Interrupts............................................................................................................... 206
15. I/O Ports................................................................................................................ 237
16. Interrupt-on-Change.............................................................................................. 285
17. (PPS) Peripheral Pin Select Module......................................................................301
18. Timer0 Module.......................................................................................................312
19. Timer1 Module with Gate Control..........................................................................321
20. Timer2 Module.......................................................................................................341
21. Capture/Compare/PWM Module........................................................................... 368
22. (PWM) Pulse-Width Modulation............................................................................ 384
23. (ZCD) Zero-Cross Detection Module.....................................................................393
24. (CWG) Complementary Waveform Generator Module..........................................401
25. (CLC) Configurable Logic Cell...............................................................................431
26. (DSM) Data Signal Modulator Module...................................................................454
27. (MSSP) Master Synchronous Serial Port Module................................................. 469
28. (EUSART) Enhanced Universal Synchronous Asynchronous Receiver Transmitter
...............................................................................................................................533
29. (FVR) Fixed Voltage Reference.............................................................................568
30. Temperature Indicator Module...............................................................................573
31. (DAC) 5-Bit Digital-to-Analog Converter Module...................................................576
32. (ADC2) Analog-to-Digital Converter with Computation Module............................. 582
33. (CMP) Comparator Module................................................................................... 630
34. (HLVD) High/Low-Voltage Detect.......................................................................... 643
35. Register Summary.................................................................................................651
36. In-Circuit Serial Programming (ICSP) .............................................................662
37. Instruction Set Summary....................................................................................... 665
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 13
38. Development Support............................................................................................764
39. Electrical Specifications.........................................................................................769
40. DC and AC Characteristics Graphs and Tables.................................................... 801
41. Packaging Information...........................................................................................802
42. Revision History.....................................................................................................824
The Microchip Web Site.............................................................................................. 825
Customer Change Notification Service........................................................................825
Customer Support....................................................................................................... 825
Product Identification System......................................................................................826
Microchip Devices Code Protection Feature............................................................... 826
Legal Notice.................................................................................................................827
Trademarks................................................................................................................. 827
Quality Management System Certified by DNV...........................................................828
Worldwide Sales and Service......................................................................................829
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 14
1. Device Overview
This document contains device specific information for the following devices:
PIC18F26Q10
PIC18F45Q10
PIC18F46Q10
This family offers the advantages of all PIC18 microcontrollers – namely, high computational performance
at an economical price – with the addition of high-endurance Program Flash Memory. In addition to these
features, the PIC18F26/45/46Q10 family introduces design enhancements that make these
microcontrollers a logical choice for many high-performance, power sensitive applications.
1.1 New Core Features
1.1.1 Low-Power Technology
All of the devices in the PIC18F26/45/46Q10 family incorporate a range of features that can significantly
reduce power consumption during operation. Key items include:
Alternate Run modes: By clocking the microcontroller from the secondary oscillator or the internal
oscillator block, power consumption during code execution can be reduced by as much as 90%.
Multiple Idle modes: The controller can also run with its CPU core disabled but the peripherals are
still active. In these states, power consumption can be reduced even further, to as little as 4% of
normal operation requirements.
On-the-fly mode switching: The Power-Managed modes are invoked by user code during operation,
allowing the user to incorporate power-saving ideas into their application’s software design.
Peripheral Module Disable: Modules that are not being used in the code can be selectively disabled
using the PMD module. This further reduces the power consumption.
1.1.2 Multiple Oscillator Options and Features
All of the devices in the PIC18F26/45/46Q10family offer several different oscillator options. The
PIC18F26/45/46Q10 family can be clocked from several different sources:
HFINTOSC
1-64 MHz precision digitally controlled internal oscillator
LFINTOSC
31 kHz internal oscillator
EXTOSC
External clock (EC)
Low-power oscillator (LP)
Medium power oscillator (XT)
High power oscillator (HS)
SOSC
Secondary oscillator circuit optimized for 31 kHz clock crystals
A Phase Lock Loop (PLL) frequency multiplier (4x) is available to the External Oscillator modes
enabling clock speeds of up to 64 MHz
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 15
Fail-Safe Clock Monitor: This option constantly monitors the main clock source against a reference
signal provided by the LFINTOSC. If a clock failure occurs, the controller is switched to the internal
oscillator block, allowing for continued operation or a safe application shutdown.
1.2 Other Special Features
Memory Endurance: The Flash cells for both program memory and data EEPROM are rated to last
for many thousands of erase/write cycles – up to 10K for program memory and 100K for EEPROM.
Data retention without refresh is conservatively estimated to be greater than 40 years.
Self-programmability: These devices can write to their own program memory spaces under internal
software control. By using a boot loader routine located in the protected Boot Block at the top of
program memory, it becomes possible to create an application that can update itself in the field.
Extended Instruction Set: The PIC18F26/45/46Q10 family includes an optional extension to the
PIC18 instruction set, which adds eight new instructions and an Indexed Addressing mode. This
extension, enabled as a device configuration option, has been specifically designed to optimize re-
entrant application code originally developed in high-level languages, such as C.
Enhanced Peripheral Pin Select: The Peripheral Pin Select (PPS) module connects peripheral inputs
and outputs to the device I/O pins. Only digital signals are included in the selections. All analog
inputs and outputs remain fixed to their assigned pins.
Enhanced Addressable EUSART: This serial communication module is capable of standard
RS-232 operation and provides support for the LIN bus protocol. Other enhancements include
automatic baud rate detection and a 16-bit Baud Rate Generator for improved resolution. When the
microcontroller is using the internal oscillator block, the EUSART provides stable operation for
applications that talk to the outside world without using an external crystal (or its accompanying
power requirement).
10-bit A/D Converter with Computation: This module incorporates programmable acquisition time,
allowing for a channel to be selected and a conversion to be initiated without waiting for a sampling
period and thus, reduce code overhead. It has a new module called ADC2 with computation features,
which provides a digital filter and threshold interrupt functions.
Windowed Watchdog Timer (WWDT):
Timer monitoring of overflow and underflow events
Variable prescaler selection
Variable window size selection
All sources configurable in hardware or software
1.3 Details on Individual Family Members
Devices in the PIC18F26/45/46Q10 family are available in 28-pin and 40/44-pin packages. The block
diagram for this device is shown in Figure 1-1.
The devices have the following differences:
1. Program Flash Memory
2. Data Memory SRAM
3. Data Memory EEPROM
4. A/D channels
5. I/O ports
6. Enhanced USART
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 16
7. Input Voltage Range/Power Consumption
All other features for devices in this family are identical. These are summarized in the following Device
Features table.
The pinouts for all devices are listed in the pin summary tables.
Table 1-1. Device Features
Features PIC18F26Q10 PIC18F45Q10 PIC18F46Q10
Program Memory (Bytes) 65536 32768 65536
Program Memory
(Instructions) 32768 16384 32768
Data Memory (Bytes) 3615 2048 3615
Data EEPROM Memory
(Bytes) 1024 256 1024
I/O Ports A,B,C,E(1) A,B,C,D,E A,B,C,D,E
Capture/Compare/PWM
Modules (CCP) 2 2 2
10-Bit Pulse-Width
Modulator (PWM) 2 2 2
10-Bit Analog-to-Digital
Module (ADC2) with
Computation Accelerator
4 internal
24 external
4 internal
35 external
4 internal
35 external
Packages
28-pin SPDIP
28-pin SOIC
28-pin SSOP
28-pin VQFN
28-pin QFN
40-pin PDIP
40-pin QFN
44-pin TQFP
40-pin PDIP
40-pin QFN
44-pin TQFP
Timers (16-/8-bit) 4/3 4/3 4/3
Serial Communications 2 MSSP,
2 EUSART
2 MSSP,
2 EUSART
2 MSSP,
2 EUSART
Enhanced Complementary
Waveform Generator
(ECWG)
1 1 1
Zero-Cross Detect (ZCD) 1 1 1
Data Signal Modulator
(DSM) 1 1 1
Configurable Logic Cell
(CLC) 8 8 8
Peripheral Pin Select (PPS) Yes Yes Yes
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 17
...........continued
Features PIC18F26Q10 PIC18F45Q10 PIC18F46Q10
Peripheral Module Disable
(PMD) Yes Yes Yes
16-bit CRC with NVMSCAN Yes Yes Yes
Programmable High/Low-
Voltage Detect (HLVD) Yes Yes Yes
Programmable Brown-out
Reset (BOR) Yes Yes Yes
Resets (and Delays)
POR, BOR,
RESET Instruction,
Stack Overflow,
Stack Underflow
(PWRT, OST),
MCLR, WDT
POR, BOR,
RESET Instruction,
Stack Overflow,
Stack Underflow
(PWRT, OST),
MCLR, WDT
POR, BOR,
RESET Instruction,
Stack Overflow,
Stack Underflow
(PWRT, OST),
MCLR, WDT
Instruction Set
75 Instructions;
83 with Extended
Instruction Set enabled
75 Instructions;
83 with Extended
Instruction Set enabled
75 Instructions;
83 with Extended
Instruction Set
enabled
Operating Frequency DC – 64 MHz DC – 64 MHz DC – 64 MHz
Note 1: PORTE contains the single RE3 read-only bit.
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 18
Figure 1-1. PIC18F26/45/46Q10 Family Block Diagram
Instruction
Decode and
Control
Data Latch
Data Memory
Address Latch
Data Address<12>
12
Access
BSR FSR0
FSR1
FSR2
inc/dec
logic
Address
4 12 4
PCH PCL
PCLATH
8
31-Level Stack
Program Counter
PRODLPRODH
8x8 Multiply
8
BITOP
8
8
ALU<8>
20
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
IR
12
3
ROM Latch
PCLATU
PCU
Note 1: RE3 is only available when MCLR functionality is disabled.
2: OSC1/CLKIN and OSC2/CLKOUT are only available in select oscillator modes.
EUSART1
Comparators MSSP1
10-bit
ADC
Timer2
Timer1
ZCD
Timer0
PWM3
HLVD
CCP1
BOR NVM
Controller
W
Instruction Bus <16>
STKPTR Bank
8
State machine
control signals
Decode
8
8
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
OSC1(2)
OSC2(2)
Brown-out
Reset
Internal
Oscillator
Fail-Safe
Clock Monitor
Precision
Reference
Band Gap
MCLR(1)
Block
LFINTOSC
Oscillator
64 MHz
Oscillator
Single-Supply
Programming
In-Circuit
Debugger
SOSCO
SOSCI
FVR
FVR
FVR
DAC
Address Latch
Program Memory
(8/16/32/64 Kbytes)
Data Latch
PORTA
RA<7:0>
PORTB
RB
<7:0>
PORTC
RC<7:0>
PORTD
RD
<7:0>
Timer4
Timer6
Timer3
Timer5
ECWG
PWM4
CCP2
C1/C2
PORTE
RE<2:0>
RE3(1)
DAC
DSM PMD
CRC-Scan
MSSP2 EUSART2
3: PORTD and PORTE<2:0> not implemented on 28-pin devices.
Rev. 30-000131B
6/14/2017
(3)
(3)
FVR
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 19
1.4 Register and Bit Naming Conventions
1.4.1 Register Names
When there are multiple instances of the same peripheral in a device, the Peripheral Control registers will
be depicted as the concatenation of a peripheral identifier, peripheral instance, and control identifier. The
control registers section will show just one instance of all the register names with an ‘x’ in the place of the
peripheral instance number. This naming convention may also be applied to peripherals when there is
only one instance of that peripheral in the device to maintain compatibility with other devices in the family
that contain more than one.
1.4.2 Bit Names
There are two variants for bit names:
Short name: Bit function abbreviation
Long name: Peripheral abbreviation + short name
1.4.2.1 Short Bit Names
Short bit names are an abbreviation for the bit function. For example, some peripherals are enabled with
the EN bit. The bit names shown in the registers are the short name variant.
Short bit names are useful when accessing bits in C programs. The general format for accessing bits by
the short name is RegisterNamebits.ShortName. For example, the enable bit, EN, in the CM1CON0
register can be set in C programs with the instruction CM1CON0bits.EN = 1.
Short names are generally not useful in assembly programs because the same name may be used by
different peripherals in different bit positions. When this occurs, during the include file generation, all
instances of that short bit name are appended with an underscore plus the name of the register in which
the bit resides to avoid naming contentions.
1.4.2.2 Long Bit Names
Long bit names are constructed by adding a peripheral abbreviation prefix to the short name. The prefix is
unique to the peripheral, thereby making every long bit name unique. The long bit name for the COG1
enable bit is the COG1 prefix, G1, appended with the enable bit short name, EN, resulting in the unique
bit name G1EN.
Important:  The COG1 peripheral is used as an example. Not all devices have the COG
peripheral.
Long bit names are useful in both C and assembly programs. For example, in C the COG1CON0 enable
bit can be set with the G1EN = 1 instruction. In assembly, this bit can be set with the BSF
COG1CON0,G1EN instruction.
1.4.2.3 Bit Fields
Bit fields are two or more adjacent bits in the same register. Bit fields adhere only to the short bit naming
convention. For example, the three Least Significant bits of the COG1CON0 register contain the Mode
Control bits. The short name for this field is MD. There is no long bit name variant. Bit field access is only
possible in C programs. The following example demonstrates a C program instruction for setting the
COG1 to the Push-Pull mode:
COG1CON0bits.MD = 0x5;
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 20
Individual bits in a bit field can also be accessed with long and short bit names. Each bit is the field name
appended with the number of the bit position within the field. For example, the Most Significant mode bit
has the short bit name MD2 and the long bit name is G1MD2. The following two examples demonstrate
assembly program sequences for setting the COG1 to Push-Pull mode:
Example 1:
MOVLW ~(1<<G1MD1)
ANDWF COG1CON0,F
MOVLW 1<<G1MD2 | 1<<G1MD0
IORWF COG1CON0,F
Example 2:
BSF COG1CON0,G1MD2
BCF COG1CON0,G1MD1
BSF COG1CON0,G1MD0
1.4.3 Register and Bit Naming Exceptions
1.4.3.1 Status, Interrupt, and Mirror Bits
Status, interrupt enables, Interrupt flags, and Mirror bits are contained in registers that span more than
one peripheral. In these cases, the bit name shown is unique so there is no prefix or short name variant.
1.4.3.2 Legacy Peripherals
There are some peripherals that do not strictly adhere to these naming conventions. Peripherals that
have existed for many years and are present in almost every device are the exceptions. These
exceptions were necessary to limit the adverse impact of the new conventions on legacy code.
Peripherals that do adhere to the new convention will include a table in the registers section indicating the
long name prefix for each peripheral instance. Peripherals that fall into the exception category will not
have this table. These peripherals include, but are not limited to the following:
EUSART
MSSP
1.5 Register Legend
The table below describes the conventions for bit types and bit Reset values used in the current data
sheet.
Table 1-2. Register Legend
Value Description
RO Read-only bit
W Writable bit
U Unimplemented bit, read as ‘0
P Programmable bit
1 Bit is set
0 Bit is cleared
xBit is unknown
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 21
...........continued
Value Description
uBit is unchanged
-n/n Value at POR and BOR/Value at all other Resets
qReset Value is determined by hardware
fReset Value is determined by fuse setting
gReset Value at POR for PPS re-mappable signals
PIC18F26/45/46Q10
Device Overview
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 22
2. Guidelines for Getting Started with PIC18F26/45/46Q10
Microcontrollers
2.1 Basic Connection Requirements
Getting started with the PIC18F26/45/46Q10 family of 8-bit microcontrollers requires attention to a
minimal set of device pin connections before proceeding with development.
The following pins must always be connected:
All VDD and VSS pins (see 2.2 Power Supply Pins)
All VDD pins must have a 0.1 uF bypass capacitor to VSS.
These pins must also be connected if they are being used in the end application:
ICSPCLK/ICSPDAT pins used for In-Circuit Serial Programming (ICSP) and debugging purposes
(see 2.4 In-Circuit Serial Programming (ICSP) Pins)
OSCI and OSCO pins when an external oscillator source is used (see 2.5 External Oscillator Pins)
MCLR pin (see 2.3 Master Clear (MCLR) Pin) when external master clear configuration is selected.
Additionally, the following pins may be required:
VREF+/VREF- pins are used when external voltage reference for analog modules is implemented
The minimum mandatory connections are shown in the figure below.
Figure 2-1. Recommended Minimum Connections
Filename: 10-000249C.vsd
Title: Getting Started on PIC18
Last Edit: 5/1/2018
First Used: PIC18FxxQ10
Note: Generic figure showing the MCLR, VDD and VSS pin connections.
C1
R1
Rev. 10-000249C
5/1/2018
VDD
PIC MCU
R2
MCLR
C2
VDD
Vss
Vss
Key:
C1: 0.1 F, 20V ceramic (recommended)
R1: 10 k (recommended)
R2: 100 to 470 (recommended)
C2: 0.1 F, 20V ceramic (required)
2.2 Power Supply Pins
2.2.1 Decoupling Capacitors
The use of decoupling capacitors on every pair of power supply pins (VDD and VSS) is required.
Consider the following criteria when using decoupling capacitors:
PIC18F26/45/46Q10
Guidelines for Getting Started with PIC18F26/45/46...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 23
Value and type of capacitor: A 0.1 μF (100 nF), 10-20V capacitor is required. The capacitor should be
a low-ESR device, with a resonance frequency in the range of 200 MHz and higher. Ceramic
capacitors are recommended.
Placement on the printed circuit board: The decoupling capacitors should be placed as close to the
pins as possible. It is recommended to place the capacitors on the same side of the board as the
device. If space is constricted, the capacitor can be placed on another layer on the PCB using a via;
however, ensure that the trace length from the pin to the capacitor is no greater than 0.25 inch (6
mm).
Handling high-frequency noise: If the board is experiencing high-frequency noise (upward of tens of
MHz), add a second ceramic type capacitor in parallel to the above described decoupling capacitor.
The value of the second capacitor can be in the range of 0.01 μF to 0.001 μF. Place this second
capacitor next to each primary decoupling capacitor. In high-speed circuit designs, consider
implementing a decade pair of capacitances as close to the power and ground pins as possible (e.g.,
0.1 μF in parallel with 0.001 μF).
Maximizing performance: On the board layout from the power supply circuit, run the power and return
traces to the decoupling capacitors first, and then to the device pins. This ensures that the
decoupling capacitors are first in the power chain. Equally important is to keep the trace length
between the capacitor and the power pins to a minimum, thereby reducing PCB trace inductance.
2.2.2 Tank Capacitors
On boards with power traces running longer than six inches in length, it is suggested to use a tank
capacitor for integrated circuits, including microcontrollers, to supply a local power source. The value of
the tank capacitor should be determined based on the trace resistance that connects the power supply
source to the device, and the maximum current drawn by the device in the application. In other words,
select the tank capacitor that meets the acceptable voltage sag at the device. Typical values range from
4.7 μF to 47 μF.
2.3 Master Clear (MCLR) Pin
The MCLR pin provides two specific device functions: Device Reset, and Device Programming and
Debugging. If programming and debugging are not required in the end application, a direct connection to
VDD may be all that is required. The addition of other components, to help increase the application’s
resistance to spurious Resets from voltage sags, may be beneficial. A typical configuration is shown in
Figure 2-1. Other circuit designs may be implemented, depending on the application’s requirements.
During programming and debugging, the resistance and capacitance that can be added to the pin must
be considered. Device programmers and debuggers drive the MCLR pin. Consequently, specific voltage
levels (VIH and VIL) and fast signal transitions must not be adversely affected. Therefore, specific values
of R1 and C1 will need to be adjusted based on the application and PCB requirements. For example, it is
recommended that the capacitor, C1, be isolated from the MCLR pin during programming and debugging
operations by using a jumper as shown in the following figure. The jumper is replaced for normal run-time
operations.
Any components associated with the MCLR pin should be placed within 0.25 inch (6 mm) of the pin.
PIC18F26/45/46Q10
Guidelines for Getting Started with PIC18F26/45/46...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 24
Figure 2-2. Example of MCLR Pin Connections
Note 1: R1 10 k is recommendedPA suggested
starting value is 10 k P Ensure that the
MCLR pin VIH and VIL specifications are metP
2: R2 470 will limit any current flowing into
MCLR from the external capacitorOC1Oin the
event of MCLR pin breakdownO due to
Electrostatic Discharge DESD( or Electrical
Overstress DEOS(PEnsure that the MCLR pin
VIH and VIL specifications are metP
C1
R2
R1
VDD
JP
MCLR
Rev. 30-000058A
6/23/2017
Note: 
1. R1 ≤ 10 kΩ is recommended. A suggested starting value is 10 kΩ. Ensure that the MCLR pin VIH
and VIL specifications are met.
2. R2 ≤ 470Ω will limit any current flowing into MCLR from the extended capacitor, C1, in the event of
MCLR pin breakdown, due to Electrostatic Discharge (ESD) or Electrical Overstress (EOS). Ensure
that the MCLR pin VIH and VIL specifications are met.
2.4 In-Circuit Serial Programming (ICSP) Pins
The ICSPCLK and ICSPDAT pins are used for ICSP and debugging purposes. It is recommended to keep
the trace length between the ICSP connector and the ICSP pins on the device as short as possible. If the
ICSP connector is expected to experience an ESD event, a series resistor is recommended, with the
value in the range of a few tens of ohms, not to exceed 100Ω.
Pull-up resistors, series diodes and capacitors on the ICSPCLK and ICSPDAT pins are not recommended
as they can interfere with the programmer/debugger communications to the device. If such discrete
components are an application requirement, they should be removed from the circuit during programming
and debugging. Alternatively, refer to the AC/DC characteristics and timing requirements information in
the respective device Flash programming specification for information on capacitive loading limits, and
pin input voltage high (VIH) and input low (VIL) requirements.
For device emulation, ensure that the “Communication Channel Select” (i.e., ICSPCLK/ICSPDAT pins),
programmed into the device, matches the physical connections for the ICSP to the Microchip debugger/
emulator tool.
For more information on available Microchip development tools connection requirements, refer to the
Development Support” section.
Related Links
38. Development Support
2.5 External Oscillator Pins
Many microcontrollers have options for at least two oscillators: a high-frequency primary oscillator and a
low-frequency secondary oscillator.
The oscillator circuit should be placed on the same side of the board as the device. Place the oscillator
circuit close to the respective oscillator pins with no more than 0.5 inch (12 mm) between the circuit
components and the pins. The load capacitors should be placed next to the oscillator itself, on the same
side of the board.
Use a grounded copper pour around the oscillator circuit to isolate it from surrounding circuits. The
grounded copper pour should be routed directly to the MCU ground. Do not run any signal traces or
PIC18F26/45/46Q10
Guidelines for Getting Started with PIC18F26/45/46...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 25
power traces inside the ground pour. Also, if using a two-sided board, avoid any traces on the other side
of the board where the crystal is placed.
Layout suggestions are shown in the following figure. In-line packages may be handled with a single-
sided layout that completely encompasses the oscillator pins. With fine-pitch packages, it is not always
possible to completely surround the pins and components. A suitable solution is to tie the broken guard
sections to a mirrored ground layer. In all cases, the guard trace(s) must be returned to ground.
Figure 2-3. Suggested Placement of the Oscillator Circuit
GND
OSCO
OSCI
Bottom Layer
Copper Pour
Oscillator
Crystal
Top Layer Copper Pour
C2
C1
DEVICE PINS
(tied to ground)
(tied to ground)
(SOSC)
Rev. 30-000059A
4/6/2017
In planning the application’s routing and I/O assignments, ensure that adjacent port pins, and other
signals in close proximity to the oscillator, are benign (i.e., free of high frequencies, short rise and fall
times, and other similar noise).
For additional information and design guidance on oscillator circuits, refer to these Microchip Application
Notes, available at the corporate website (www.microchip.com):
PIC18F26/45/46Q10
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 26
AN826, “Crystal Oscillator Basics and Crystal Selection for rfPIC and PICmicro® Devices”
AN849, “Basic PICmicro® Oscillator Design”
AN943, “Practical PICmicro® Oscillator Analysis and Design”
AN949, “Making Your Oscillator Work”
Related Links
4. Oscillator Module (with Fail-Safe Clock Monitor)
2.6 Unused I/Os
Unused I/O pins should be configured as outputs and driven to a logic low state. Alternatively, connect a 1
kΩ to 10 kΩ resistor to VSS on unused pins to drive the output to logic low.
PIC18F26/45/46Q10
Guidelines for Getting Started with PIC18F26/45/46...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 27
3. Device Configuration
Device configuration consists of Configuration Words, Code Protection, Device ID and Rev ID.
3.1 Configuration Words
There are six Configuration Words that allow the user to select the device oscillator, reset, and memory
protection options. These are implemented as Configuration Word 1 through Configuration Word 6 at
300000h through 30000Bh.
Important:  The DEBUG bit in Configuration Words is managed automatically by device
development tools including debuggers and programmers. For normal device operation, this bit
should be maintained as a ‘1’.
3.2 Code Protection
Code protection allows the device to be protected from unauthorized access. Program memory protection
and data memory protection are controlled independently. Internal access to the program memory is
unaffected by any code protection setting.
3.2.1 Program Memory Protection
The entire program memory space is protected from external reads and writes by the CP bit. When CP =
0, external reads and writes of program memory are inhibited and a read will return all ‘0’s. The CPU can
continue to read program memory, regardless of the protection bit settings. Self-writing the program
memory is dependent upon the write protection setting.
3.2.2 Data Memory Protection
The entire data EEPROM memory space is protected from external reads and writes by the CPD bit.
When CPD = 0, external reads and writes of data EEPROM memory are inhibited and a read will return
all ‘0’s. The CPU can continue to read data EEPROM memory regardless of the protection bit settings.
3.3 Write Protection
Write protection allows the device to be protected from unintended self-writes. Applications, such as boot
loader software, can be protected while allowing other regions of the program memory to be modified.
The WRT bits define the size of the program memory block that is protected.
3.4 User ID
256 bytes in the memory space (200000h-20000FFh) are designated as ID locations where the user can
store checksum or other code identification numbers. These locations are readable and writable during
normal execution. See the “User ID, Device ID and Configuration Word Access” section for more
information on accessing these memory locations. For more information on checksum calculation, see
the “PIC18F26/45/46Q10 Memory Programming Specification”, (DS40001874).
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 28
3.5 Device ID and Revision ID
The 16-bit Device ID word is located at 0x3FFFFE and the 16-bit revision ID is located at 0x3FFFFC.
These locations are read-only and cannot be erased or modified.
Development tools, such as device programmers and debuggers, may be used to read the Device ID,
Revision ID and Configuration Words. Refer to the “Nonvolatile Memory (NVM) Control” section for
more information on accessing these locations.
Related Links
11. (NVM) Nonvolatile Memory Control
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 29
3.6 Register Summary - Configuration Words
Address Name Bit Pos.
0x300000 CONFIG1
7:0 RSTOSC[2:0] FEXTOSC[2:0]
15:8 FCMEN CSWEN CLKOUTEN
0x300002 CONFIG2
7:0 BOREN[1:0] LPBOREN PWRTE MCLRE
15:8 XINST DEBUG STVREN PPS1WAY ZCD BORV[1:0]
0x300004 CONFIG3
7:0 WDTE[1:0] WDTCPS[4:0]
15:8 WDTCCS[2:0] WDTCWS[2:0]
0x300006 CONFIG4
7:0 WRT3 WRT2 WRT1 WRT0
15:8 LVP SCANE WRTD WRTB WRTC
0x300008 CONFIG5
7:0 CPD CP
15:8
0x30000A CONFIG6
7:0 EBTR3 EBTR2 EBTR1 EBTR0
15:8 EBTRB
3.7 Register Definitions: Configuration Words
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 30
3.7.1 CONFIG1
Name:  CONFIG1
Address:  0x300000
Configuration Word 1
Oscillators
Bit 15 14 13 12 11 10 9 8
FCMEN CSWEN CLKOUTEN
Access R/W R/W R/W
Reset 1 1 1
Bit 7 6 5 4 3 2 1 0
RSTOSC[2:0] FEXTOSC[2:0]
Access R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1
Bit 13 – FCMEN Fail-Safe Clock Monitor Enable bit
Value Description
1Fail-Safe Clock Monitor enabled
0Fail-Safe Clock Monitor disabled
Bit 11 – CSWEN Clock Switch Enable bit
Value Description
1Writing to NOSC and NDIV is allowed
0The NOSC and NDIV bits cannot be changed by user software
Bit 8 – CLKOUTEN Clock Out Enable bit
If FEXTOSC = HS, XT, LP, then this bit is ignored.
Otherwise:
Value Description
1CLKOUT function is disabled; I/O function on OSC2
0CLKOUT function is enabled; FOSC/4 clock appears at OSC2
Bits 6:4 – RSTOSC[2:0] Power-up Default Value for COSC bits
This value is the Reset default value for COSC and selects the oscillator first used by user software.
Refer to COSC operation.
Value Description
111 EXTOSC operating per FEXTOSC bits (device manufacturing default)
110 HFINTOSC with HFFRQ = 4 MHz and CDIV = 4:1
101 LFINTOSC
100 SOSC
011 Reserved
010 EXTOSC with 4x PLL, with EXTOSC operating per FEXTOSC bits
001 Reserved
000 HFINTOSC with HFFRQ = 64 MHz and CDIV = 1:1. Resets COSC/NOSC to b'110'.
Bits 2:0 – FEXTOSC[2:0] FEXTOSC External Oscillator Mode Selection bits
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 31
Value Description
111 ECH (external clock) above 16 MHz
110 ECM (external clock) for 500 kHz to 16 MHz
101 ECL (external clock) below 500 kHz
100 Oscillator not enabled
011 Reserved (do not use)
010 HS (crystal oscillator) above 4 MHz
001 XT (crystal oscillator) above 500 kHz, below 4 MHz
000 LP (crystal oscillator) optimized for 32.768 kHz
Related Links
4.6.5 OSCFRQ
4.6.2 OSCCON2
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 32
3.7.2 CONFIG2
Name:  CONFIG2
Address:  0x300002
Configuration Word 2
Supervisor
Bit 15 14 13 12 11 10 9 8
XINST DEBUG STVREN PPS1WAY ZCD BORV[1:0]
Access R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1
Bit 7 6 5 4 3 2 1 0
BOREN[1:0] LPBOREN PWRTE MCLRE
Access R/W R/W R/W R/W R/W
Reset 0 1 1 1 1
Bit 15 – XINST Extended Instruction Set Enable bit
Value Description
1Extended Instruction Set and Indexed Addressing mode disabled (Legacy mode)
0Extended Instruction Set and Indexed Addressing mode enabled
Bit 13 – DEBUG Debugger Enable bit
Value Description
1Background debugger disabled
0Background debugger enabled
Bit 12 – STVREN Stack Overflow/Underflow Reset Enable bit
Value Description
1Stack Overflow or Underflow will cause a Reset
0Stack Overflow or Underflow will not cause a Reset
Bit 11 – PPS1WAY PPSLOCKED bit One-Way Set Enable bit
Value Description
1The PPSLOCKED bit can only be set once after an unlocking sequence is executed; once
PPSLOCK is set, all future changes to PPS registers are prevented
0The PPSLOCKED bit can be set and cleared as needed (provided an unlocking sequence is
executed)
Bit 10 – ZCD ZCD Disable bit
Value Description
1ZCD disabled. ZCD can be enabled by setting the ZCDSEN bit of ZCDCON
0ZCD always enabled, PMDx[ZCDMD] bit is ignored
Bits 9:8 – BORV[1:0] Brown-out Reset Voltage Selection bit
Value Description
11 Brown-out Reset Voltage (VBOR) set to 1.90V
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 33
...........continued
Value Description
10 Brown-out Reset Voltage (VBOR) set to 2.45V
01 Brown-out Reset Voltage (VBOR) set to 2.7V
00 Brown-out Reset Voltage (VBOR) set to 2.85V
Bits 7:6 – BOREN[1:0] Brown-out Reset Enable bits
When enabled, Brown-out Reset Voltage (VBOR) is set by BORV bit
Value Description
11 Brown-out Reset enabled, SBOREN bit is ignored
10 Brown-out Reset enabled while running, disabled in Sleep; SBOREN is ignored
01 Brown-out Reset enabled according to SBOREN
00 Brown-out Reset disabled
Bit 5 – LPBOREN Low-Power BOR Enable bit
Value Description
1Low-Power Brown-out Reset is disabled
0Low-Power Brown-out Reset is enabled
Bit 1 – PWRTE Power-up Timer Enable bit
Value Description
1PWRT disabled
0PWRT enabled
Bit 0 – MCLRE Master Clear (MCLR) Enable bit
Value Condition Description
xIf LVP = 1RE3 pin function is MCLR
1If LVP = 0MCLR pin is MCLR
0If LVP = 0MCLR pin function is port defined function
Note:  BORV - The higher voltage setting is recommended for operation at or above 16 MHz.
Related Links
7.4.3 PMD2
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 34
3.7.3 CONFIG3
Name:  CONFIG3
Address:  0x300004
Configuration Word 3
Windowed Watchdog Timer
Bit 15 14 13 12 11 10 9 8
WDTCCS[2:0] WDTCWS[2:0]
Access R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1
Bit 7 6 5 4 3 2 1 0
WDTE[1:0] WDTCPS[4:0]
Access R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1
Bits 13:11 – WDTCCS[2:0] WDT Input Clock Selector bits
Value Condition Description
xWDTE=00 These bits have no effect
111 WDTE≠00 Software Control
110 to
010
WDTE≠00 Reserved (Default to LFINTOSC)
001 WDTE≠00 WDT reference clock is the 31.25 kHz MFINTOSC
000 WDTE≠00 WDT reference clock is the 31.0 kHz LFINTOSC (default value)
Bits 10:8 – WDTCWS[2:0] WDT Window Select bits
WDTCWS
WDTCON1[WINDOW] at POR
Software control of
WINDOW
Keyed access
required?
Value Window delay
Percent of time
Window opening
Percent of time
111 111 n/a 100 Yes No
110 110 n/a 100
No Yes
101 101 25 75
100 100 37.5 62.5
011 011 50 50
010 010 62.5 37.5
001 001 75 25
000 000 87.5 12.5
Bits 6:5 – WDTE[1:0] WDT Operating Mode bits
Value Description
11 WDT enabled regardless of Sleep; SEN bit in WDTCON0 is ignored
10 WDT enabled while Sleep = 0, suspended when Sleep = 1; SEN bit in WDTCON0 is ignored
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 35
Value Description
01 WDT enabled/disabled by SEN bit in WDTCON0
00 WDT disabled, SEN bit in WDTCON0 is ignored
Bits 4:0 – WDTCPS[4:0] WDT Period Select bits
WDTCPS
WDTCON0[WDTPS] at POR
Software Control of WDTPS?
Value Divider Ratio Typical Time-Out
(FIN = 31 kHz)
11111 01011 1:65536 216 2s Yes
11110
...
10011
11110
...
10011
1:32 251 ms No
10010 10010 1:8388608 223 256s
No
10001 10001 1:4194304 222 128s
10000 10000 1:2097152 221 64s
01111 01111 1:1048576 220 32s
01110 01110 1:524299 219 16s
01101 01101 1:262144 218 8s
01100 01100 1:131072 217 4s
01011 01011 1:65536 216 2s
01010 01010 1:32768 215 1s
01001 01001 1:16384 214 512 ms
01000 01000 1:8192 213 256 ms
00111 00111 1:4096 212 128 ms
00110 00110 1:2048 211 64 ms
00101 00101 1:1024 210 32 ms
00100 00100 1:512 2916 ms
00011 00011 1:256 288 ms
00010 00010 1:128 274 ms
00001 00001 1:64 262 ms
00000 00000 1:32 251 ms
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 36
3.7.4 CONFIG4
Name:  CONFIG4
Address:  0x300006
Configuration Word 4
Memory Write Protection
Bit 15 14 13 12 11 10 9 8
LVP SCANE WRTD WRTB WRTC
Access R/W R/W R/W R/W R/W
Reset 1 1 1 1 1
Bit 7 6 5 4 3 2 1 0
WRT3 WRT2 WRT1 WRT0
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bit 13 – LVP Low-Voltage Programming Enable bit
The LVP bit cannot be written (to zero) while operating from the LVP programming interface. The purpose
of this rule is to prevent the user from dropping out of LVP mode while programming from LVP mode, or
accidentally eliminating LVP mode from the Configuration state.
Value Description
1Low-voltage programming enabled. MCLR/VPP pin function is MCLR. MCLRE Configuration
bit is ignored.
0HV on MCLR/VPP must be used for programming
Bit 12 – SCANE Scanner Enable bit
Value Description
1Scanner module is available for use, PMD0[SCANMD] bit enables the module
0Scanner module is NOT available for use, PMD0[SCANMD] bit is ignored
Bit 10 – WRTD Data EEPROM Write Protection bit
Value Description
1Data EEPROM NOT write-protected
0Data EEPROM write-protected
Bit 9 – WRTB Boot Block Write Protection bit
Value Description
1Boot Block NOT write-protected
0Boot Block write-protected
Bit 8 – WRTC Configuration Register Write Protection bit
Value Description
1Configuration Registers NOT write-protected
0Configuration Registers write-protected
Bits 0, 1, 2, 3 – WRTn User NVM Self-Write Protection bits
Value Description
1Corresponding Memory Block NOT write-protected
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 37
Value Description
0Corresponding Memory Block write-protected
Related Links
10.1 Program Memory Organization
11.3.4 Operation During Code-Protect and Write-Protect
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 38
3.7.5 CONFIG5
Name:  CONFIG5
Address:  0x300008
Configuration Word 5
Code Protection
Bit 15 14 13 12 11 10 9 8
Access
Reset
Bit 7 6 5 4 3 2 1 0
CPD CP
Access RO RO
Reset 1 1
Bit 1 – CPD Data NVM (DFM) Memory Code Protection bit
Value Description
1Data NVM code protection disabled
0Data NVM code protection enabled
Bit 0 – CP User NVM Program Memory Code Protection bit
Value Description
1User NVM code protection disabled
0User NVM code protection enabled
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 39
3.7.6 CONFIG6
Name:  CONFIG6
Address:  0x30000A
Configuration Word 6
Memory Read Protection
Bit 15 14 13 12 11 10 9 8
EBTRB
Access R/W
Reset 1
Bit 7 6 5 4 3 2 1 0
EBTR3 EBTR2 EBTR1 EBTR0
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bit 9 – EBTRB Table Read Protection bit
Value Description
1Memory Boot Block NOT protected from table reads executed in other blocks
0Memory Boot Block protected from table reads executed in other blocks
Bits 0, 1, 2, 3 – EBTRn Table Read Protection bits
Value Description
1Corresponding Memory Block NOT protected from table reads executed in other blocks
0Corresponding Memory Block protected from table reads executed in other blocks
Related Links
10.1 Program Memory Organization
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 40
3.8 Register Summary - Device and Revision
Address Name Bit Pos.
0x3FFFFC REVISION ID
7:0 MJRREV[1:0] MNRREV[5:0]
15:8 1010[3:0] MJRREV[5:2]
0x3FFFFE DEVICE ID
7:0 DEV[7:0]
15:8 DEV[15:8]
3.9 Register Definitions: Device and Revision
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 41
3.9.1 DEVICE ID
Name:  DEVICE ID
Address:  0x3FFFFE
Device ID Register
Bit 15 14 13 12 11 10 9 8
DEV[15:8]
Access RO RO RO RO RO RO RO RO
Reset q q q q q q q q
Bit 7 6 5 4 3 2 1 0
DEV[7:0]
Access RO RO RO RO RO RO RO RO
Reset q q q q q q q q
Bits 15:0 – DEV[15:0]
Device ID bits
Device Device ID
PIC18F26Q10 7180h
PIC18F45Q10 7140h
PIC18F46Q10 7120h
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 42
3.9.2 REVISION ID
Name:  REVISION ID
Address:  0x3FFFFC
Revision ID Register
Bit 15 14 13 12 11 10 9 8
1010[3:0] MJRREV[5:2]
Access RO RO RO RO RO RO RO RO
Reset 1 0 1 0 q q q q
Bit 7 6 5 4 3 2 1 0
MJRREV[1:0] MNRREV[5:0]
Access RO RO RO RO RO RO RO RO
Reset q q q q q q q q
Bits 15:12 – 1010[3:0] Read as ‘1010’
These bits are fixed with value ‘1010’ for all devices in this family.
Bits 11:6 – MJRREV[5:0] Major Revision ID bits
These bits are used to identify a major revision. A major revision is indicated by an all-layer revision (A0,
B0, C0, etc.).
Revision A = b'00 0000'
Bits 5:0 – MNRREV[5:0] Minor Revision ID bits
These bits are used to identify a minor revision.
PIC18F26/45/46Q10
Device Configuration
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 43
4. Oscillator Module (with Fail-Safe Clock Monitor)
4.1 Overview
The oscillator module has multiple clock sources and selection features that allow it to be used in a wide
range of applications while maximizing performance and minimizing power consumption. Figure 4-1
illustrates a block diagram of the oscillator module.
Clock sources can be supplied from external oscillators, quartz-crystal resonators and ceramic
resonators. In addition, the system clock source can be supplied from one of two internal oscillators and
PLL circuits, with a choice of speeds selectable via software. Additional clock features include:
Selectable system clock source between external or internal sources via software.
Fail-Safe Clock Monitor (FSCM) designed to detect a failure of the external clock source (LP, XT, HS,
ECH, ECM, ECL) and switch automatically to the internal oscillator.
Oscillator Start-up Timer (OST) ensures stability of crystal oscillator sources.
The RSTOSC bits of Configuration Word 1 determine the type of oscillator that will be used when the
device runs after Reset, including when it is first powered up.
If an external clock source is selected, the FEXTOSC bits of Configuration Word 1 must be used in
conjunction with the RSTOSC bits to select the External Clock mode.
The external oscillator module can be configured in one of the following clock modes, by setting the
FEXTOSC<2:0> bits of Configuration Word 1:
ECL – External Clock Low-Power mode
(below 100 kHz)
ECM – External Clock Medium Power mode
(100 kHz to 16 MHz)
ECH – External Clock High-Power mode
(above 16 MHz)
LP – 32 kHz Low-Power Crystal mode
XT – Medium Gain Crystal or Ceramic Resonator Oscillator mode (between 500 kHz and 4 MHz)
HS – High Gain Crystal or Ceramic Resonator mode (above 4 MHz)
The ECH, ECM, and ECL Clock modes rely on an external logic level signal as the device clock source.
The LP, XT, and HS Clock modes require an external crystal or resonator to be connected to the device.
Each mode is optimized for a different frequency range. The internal oscillator block produces low and
high-frequency clock sources, designated LFINTOSC and HFINTOSC. Multiple device clock frequencies
may be derived from these clock sources.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 44
Figure 4-1. Simplified PIC® MCU Clock Source Block Diagram
Filename: 10-000208D.vsd
Title: Simplified Clock Source Block Diagram for PIC18(L)F2x/4x/6xK40
Last Edit: 5/10/2016
First Used: PIC18(L)F2x/4x/6xK40 (MVAE,MVAF,MVAB,MVAC,MVAK)
Notes:
Rev. 10-000208D
5/10/2016
FRQ<3:0>
HFINTOSC
Secondary
Oscillator
(SOSC)
External
Oscillator
(EXTOSC)
CLKIN/OSC1
CLKOUT/OSC2
SOSCIN/SOSCI
SOSCO
31 kHz
Oscillator
4x PLL
000
110
011
001
101
100
010
111
COSC<2:0>
LFINTOSC
1,2,4,8,12,16,32,48,64
MHz
Oscillator
Post-Divider
1000
1001
0000
0011
0010
0001
0100
0101
0110
0111
512
256
128
64
32
16
8
4
2
1
CDIV<4:0>
Sleep
Idle
Sleep
SYSCMD
System Clock
Peripheral Clock
FSCM
To Peripherals
To Peripherals
To Peripherals
MFINTOSC
31.25 kHz and 500 kHz
Oscillator
To Peripherals
Reserved
Reserved
Reserved
LFINTOSC is used to
monitor system clock
Related Links
3.7.1 CONFIG1
4.2 Clock Source Types
Clock sources can be classified as external or internal.
External clock sources rely on external circuitry for the clock source to function. Examples are: oscillator
modules (ECH, ECM, ECL mode), quartz crystal resonators or ceramic resonators (LP, XT and HS
modes).
Internal clock sources are contained within the oscillator module. The internal oscillator block has two
internal oscillators that are used to generate internal system clock sources. The High-Frequency Internal
Oscillator (HFINTOSC) can produce 1, 2, 4, 8, 12, 16, 32, 48 and 64 MHz clock. The frequency can be
controlled through the OSCFRQ register. The Low-Frequency Internal Oscillator (LFINTOSC) generates a
fixed 31 kHz frequency.
A 4x PLL is provided that can be used in conjunction with the external clock.
The system clock can be selected between external or internal clock sources via the NOSC bits. The
system clock can be made available on the OSC2/CLKOUT pin for any of the modes that do not use the
OSC2 pin. The clock out functionality is governed by the CLKOUTEN bit in the CONFIG1H register. If
enabled, the clock out signal is always at a frequency of FOSC/4.
Related Links
4.6.5 OSCFRQ
4.2.1.4 4x PLL
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 45
4.3 Clock Switching
4.2.1 External Clock Sources
An external clock source can be used as the device system clock by performing one of the following
actions:
Program the RSTOSC<2:0> and FEXTOSC<2:0> bits in the Configuration Words to select an
external clock source that will be used as the default system clock upon a device Reset.
Write the NOSC<2:0> and NDIV<3:0> bits to switch the system clock source.
Related Links
4.3 Clock Switching
4.2.1.1 EC Mode
The External Clock (EC) mode allows an externally generated logic level signal to be the system clock
source. When operating in this mode, an external clock source is connected to the OSC1 input. OSC2/
CLKOUT is available for general purpose I/O or CLKOUT. The following figure shows the pin connections
for EC mode.
EC mode has three power modes to select from through Configuration Words:
ECH – High power, above 16 MHz
ECM – Medium power, 100 kHz-16 MHz
ECL – Low power, below 100 kHz
The Oscillator Start-up Timer (OST) is disabled when EC mode is selected. Therefore, there is no delay
in operation after a Power-on Reset (POR) or wake-up from Sleep. Because the PIC® MCU design is fully
static, stopping the external clock input will have the effect of halting the device while leaving all data
intact. Upon restarting the external clock, the device will resume operation as if no time had elapsed.
Figure 4-2. External Clock (EC) Mode Operation
OSC1/CLKIN
OSC2/CLKOUT
Clock from
Ext. System
PIC®MCU
FOSC/4 or I/O(1)
Rev. 30-000060A
4/6/2017
Note: 
1. Output depends upon CLKOUTEN bit of the Configuration Words (CONFIG1H).
4.2.1.2 LP, XT, HS Modes
The LP, XT and HS modes support the use of quartz crystal resonators or ceramic resonators connected
to OSC1 and OSC2 (Figure 4-3). The three modes select a low, medium or high gain setting of the
internal inverter-amplifier to support various resonator types and speed.
LP Oscillator mode selects the lowest gain setting of the internal inverter-amplifier. LP mode current
consumption is the least of the three modes. This mode is designed to drive only 32.768 kHz tuning-fork
type crystals (watch crystals).
XT Oscillator mode selects the intermediate gain setting of the internal inverter-amplifier. XT mode current
consumption is the medium of the three modes. This mode is best suited to drive resonators with a
medium drive level specification (between 100 kHz - 4 MHz).
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 46
HS Oscillator mode selects the highest gain setting of the internal inverter-amplifier. HS mode current
consumption is the highest of the three modes. This mode is best suited for resonators that require a high
drive setting (above 4 MHz).
Figure 4-3 and Figure 4-4 show typical circuits for quartz crystal and ceramic resonators, respectively.
Figure 4-3. Quartz Crystal Operation (LP, XT or HS Mode)
C1
C2
Quartz
RS(1)
OSC1/CLKIN
RF(2) Sleep
To Internal
Logic
PIC®MCU
Crystal
OSC2/CLKOUT
Rev. 30-000061A
4/6/2017
Note: 
1. A series resistor (RS) may be required for quartz crystals with low drive level.
2. The value of RF varies with the Oscillator mode selected (typically between 2 MΩ to 10 MΩ).
Figure 4-4. Ceramic Resonator Operation
(XT or HS Mode)
C1
C2 Ceramic RS(1)
OSC1/CLKIN
RF(2) Sleep
To Internal
Logic
PIC®MCU
RP(3)
Resonator
OSC2/CLKOUT
Rev. 30-000062A
4/6/2017
Note: 
1. A series resistor (RS) may be required for ceramic resonators with low drive level.
2. The value of RF varies with the Oscillator mode selected (typically between 2 MΩ to 10 MΩ).
3. An additional parallel feedback resistor (RP) may be required for proper ceramic resonator
operation.
4.2.1.3 Oscillator Start-up Timer (OST)
If the oscillator module is configured for LP, XT or HS modes, the Oscillator Start-up Timer (OST) counts
1024 oscillations from OSC1. This occurs following a Power-on Reset (POR), or a wake-up from Sleep.
The OST ensures that the oscillator circuit, using a quartz crystal resonator or ceramic resonator, has
started and is providing a stable system clock to the oscillator module.
4.2.1.4 4x PLL
The oscillator module contains a 4x PLL that can be used with the external clock sources to provide a
system clock source. The input frequency for the PLL must fall within specifications.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 47
The PLL can be enabled for use by one of two methods:
1. Program the RSTOSC bits in the Configuration Word 1 to ‘010’ (enable EXTOSC with 4x PLL).
2. Write the NOSC bits to ‘010’ (enable EXTOSC with 4x PLL).
Related Links
39.4.3 PLL Specifications
4.2.1.5 Secondary Oscillator
The secondary oscillator is a separate oscillator block that can be used as an alternate system clock
source. The secondary oscillator is optimized for 32.768 kHz, and can be used with an external crystal
oscillator connected to the SOSCI and SOSCO device pins, or an external clock source connected to the
SOSCIN pin. The secondary oscillator can be selected during run-time using clock switching.
Figure 4-5. Quartz Crystal Operation (Secondary Oscillator)
C1
C2
32.768 kHz
SOSCI
To Internal
Logic
PIC®MCU
Crystal
SOSCO
Quartz
Rev. 30-000063A
4/6/2017
Note: 
1. Quartz crystal characteristics vary according to type, package and manufacturer. The user should
consult the manufacturer data sheets for specifications and recommended application.
2. Always verify oscillator performance over the VDD and temperature range that is expected for the
application.
3. For oscillator design assistance, reference the following Microchip Application Notes:
AN826, “Crystal Oscillator Basics and Crystal Selection for PIC® and PIC® Devices” (DS00826)
AN849, “Basic PIC® Oscillator Design” (DS00849)
AN943, “Practical PIC® Oscillator Analysis and Design” (DS00943)
AN949, “Making Your Oscillator Work” (DS00949)
TB097, “Interfacing a Micro Crystal MS1V-T1K 32.768 kHz Tuning Fork Crystal to a
PIC16F690/SS” (DS91097)
AN1288, “Design Practices for Low-Power External Oscillators” (DS01288)
Related Links
4.3 Clock Switching
4.2.2 Internal Clock Sources
The device may be configured to use the internal oscillator block as the system clock by performing one
of the following actions:
Program the RSTOSC<2:0> bits in Configuration Words to select the INTOSC clock as the default
system clock upon a device Reset.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 48
Write the NOSC<2:0> bits to switch the system clock source to the internal oscillator during run-time.
In INTOSC mode, OSC1/CLKIN is available for general purpose I/O. OSC2/CLKOUT is available for
general purpose I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined by the CLKOUTEN bit in Configuration Words.
The internal oscillator block has two independent oscillators that can produce two internal system clock
sources.
1. The HFINTOSC (High-Frequency Internal Oscillator) is factory-calibrated and operates from 1 to 64
MHz. The frequency of HFINTOSC can be selected through the OSCFRQ Frequency Selection
register, and fine-tuning can be done via the OSCTUNE register.
2. The LFINTOSC (Low-Frequency Internal Oscillator) is factory-calibrated and operates at 31 kHz.
Related Links
4.3 Clock Switching
4.6.5 OSCFRQ
4.6.6 OSCTUNE
4.2.2.1 HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is a precision digitally-controlled internal clock
source that produces a stable clock up to 64 MHz. The HFINTOSC can be enabled through one of the
following methods:
Programming the RSTOSC<2:0> bits in Configuration Word 1 to ‘110’ (FOSC = 1 MHz) or ‘000’ (FOSC
= 64 MHz) to set the oscillator upon device Power-up or Reset.
Write to the NOSC<2:0> bits during run-time.
The HFINTOSC frequency can be selected by setting the HFFRQ<3:0> bits.
The NDIV<3:0> bits allow for division of the HFINTOSC output from a range between 1:1 and 1:512.
Related Links
4.3 Clock Switching
4.2.2.2 MFINTOSC
The module provides two (500 kHz and 31.25 kHz) constant clock outputs. These clocks are digital
divisors of the HFINTOSC clock. Dynamic divider logic is used to provide constant MFINTOSC clock
rates for all settings of HFINTOSC.
The MFINTOSC cannot be used to drive the system but it is used to clock certain modules such as the
Timers and WWDT.
4.2.2.3 LFINTOSC
The Low-Frequency Internal Oscillator (LFINTOSC) is a factory-calibrated 31 kHz internal clock source.
The LFINTOSC is the frequency for the Power-up Timer (PWRT), Windowed Watchdog Timer (WWDT)
and Fail-Safe Clock Monitor (FSCM).
The LFINTOSC is enabled through one of the following methods:
Programming the RSTOSC<2:0> bits of Configuration Word 1 to enable LFINTOSC.
Write to the NOSC<2:0> bits during run-time.
Related Links
4.3 Clock Switching
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 49
4.2.2.4 ADCRC (also referred to as FRC)
The ADCRC is an oscillator dedicated to the ADC2 module. The ADCRC oscillator can be manually
enabled using the ADOEN bit. The ADCRC runs at a fixed frequency of 600 kHz. ADCRC is automatically
enabled if it is selected as the clock source for the ADC2 module.
4.2.3 Oscillator Status and Adjustments
4.2.3.1 Internal Oscillator Frequency Adjustment
The internal oscillator is factory-calibrated. This internal oscillator can be adjusted in software by writing
to the OSCTUNE register.
The default value of the OSCTUNE register is 00h. The value is a 6-bit two’s complement number. A
value of 1Fh will provide an adjustment to the maximum frequency. A value of 20h will provide an
adjustment to the minimum frequency.
When the OSCTUNE register is modified, the oscillator frequency will begin shifting to the new frequency.
Code execution continues during this shift. There is no indication that the shift has occurred.
OSCTUNE does not affect the LFINTOSC frequency. Operation of features that depend on the
LFINTOSC clock source frequency, such as the Power-up Timer (PWRT), WWDT, Fail-Safe Clock
Monitor (FSCM) and peripherals, are not affected by the change in frequency.
Related Links
4.6.6 OSCTUNE
4.2.3.2 Oscillator Status and Manual Enable
The Ready status of each oscillator (including the ADCRC oscillator) is displayed in OSCSTAT. The
oscillators (but not the PLL) may be explicitly enabled through OSCEN.
Related Links
4.6.4 OSCSTAT
4.6.7 OSCEN
4.2.3.3 HFOR and MFOR Bits
The HFOR and MFOR bits indicate that the HFINTOSC and MFINTOSC is ready. These clocks are
always valid for use at all times, but only accurate after they are ready.
When a new value is loaded into the OSCFRQ register, the HFOR and MFOR bits will clear, and set
again when the oscillator is ready. During pending OSCFRQ changes the MFINTOSC clock will stall at a
high or a low state, until the HFINTOSC resumes operation.
4.3 Clock Switching
The system clock source can be switched between external and internal clock sources via software using
the New Oscillator Source (NOSC) bits. The following clock sources can be selected using the following:
External oscillator
Internal Oscillator Block (INTOSC)
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 50
Important:  The Clock Switch Enable bit in Configuration Word 1 can be used to enable or
disable the clock switching capability. When cleared, the NOSC and NDIV bits cannot be
changed by user software. When set, writing to NOSC and NDIV is allowed and would
switch the clock frequency.
4.3.1 New Oscillator Source (NOSC) and New Divider Selection Request (NDIV) Bits
The New Oscillator Source (NOSC) and New Divider Selection Request (NDIV) bits select the system
clock source and frequency that are used for the CPU and peripherals.
When new values of NOSC and NDIV are written to OSCCON1, the current oscillator selection will
continue to operate while waiting for the new clock source to indicate that it is stable and ready. In some
cases, the newly requested source may already be in use, and is ready immediately. In the case of a
divider-only change, the new and old sources are the same, so the source will be ready immediately. The
device may enter Sleep while waiting for the switch.
When the new oscillator is ready, the New Oscillator Ready (NOSCR) bit is set and also the Clock Switch
Interrupt Flag (CSWIF) bit of PIR1 sets. If Clock Switch Interrupts are enabled (CSWIE = 1), an interrupt
will be generated at that time. The Oscillator Ready (ORDY) bit can also be polled to determine when the
oscillator is ready in lieu of an interrupt.
Important:  The CSWIF interrupt will not wake the system from Sleep.
If the Clock Switch Hold (CSWHOLD) bit is clear, the oscillator switch will occur when the New Oscillator
is Ready bit (NOSCR) is set, and the interrupt (if enabled) will be serviced at the new oscillator setting.
If CSWHOLD is set, the oscillator switch is suspended, while execution continues using the current (old)
clock source. When the NOSCR bit is set, software should:
Set CSWHOLD = 0 so the switch can complete, or
Copy COSC into NOSC to abandon the switch.
If DOZE is in effect, the switch occurs on the next clock cycle, whether or not the CPU is operating during
that cycle.
Changing the clock post-divider without changing the clock source (i.e., changing FOSC from 1 MHz to 2
MHz) is handled in the same manner as a clock source change, as described previously. The clock
source will already be active, so the switch is relatively quick. CSWHOLD must be clear (CSWHOLD = 0)
for the switch to complete.
The current COSC and CDIV are indicated in the OSCCON2 register up to the moment when the switch
actually occurs, at which time OSCCON2 is updated and ORDY is set. NOSCR is cleared by hardware to
indicate that the switch is complete.
Related Links
4.3.3 Clock Switch and Sleep
4.3.2 PLL Input Switch
Switching between the PLL and any non-PLL source is managed as described above. The input to the
PLL is established when NOSC selects the PLL, and maintained by the COSC setting.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 51
When NOSC and COSC select the PLL with different input sources, the system continues to run using
the COSC setting, and the new source is enabled per NOSC. When the new oscillator is ready (and
CSWHOLD = 0), system operation is suspended while the PLL input is switched and the PLL acquires
lock. This provides a truly glitch-free clock switch operation.
Important:  If the PLL fails to lock, the FSCM will trigger.
4.3.3 Clock Switch and Sleep
If OSCCON1 is written with a new value and the device is put to Sleep before the switch completes, the
switch will not take place and the device will enter Sleep mode.
When the device wakes from Sleep and the CSWHOLD bit is clear, the device will wake with the ‘new’
clock active, and the Clock Switch Interrupt Flag bit (CSWIF) will be set.
When the device wakes from Sleep and the CSWHOLD bit is set, the device will wake with the ‘old’ clock
active and the new clock will be requested again.
Figure 4-6. Clock Switch (CSWHOLD = 0)
Note 1: CSWIF is asserted coincident with NOSCR; interrupt is serviced at OSC#2 speed.
2: The assertion of NOSCR is hidden from the user because it appears only for the duration of the switch.
CSWHOLD
NOSCR
OSC #2
CSWIF
OSCCON1
WRITTEN
NOTE 1
USER
CLEAR
OSC #1
NOTE 2
ORDY
Rev. 30-000064A
4/7/2016
Note: 
1. CSWIF is asserted coincident with NOSCR; interrupt is serviced at OSC#2 speed.
2. The assertion of NOSCR is hidden from the user because it appears only for the duration of the
switch.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 52
Figure 4-7. Clock Switch (CSWHOLD = 1)
Note 1: CSWIF is asserted coincident with NOSCR, and may be cleared before or after clearing CSWHOLD = 0.
CSWHOLD
NOSCR
OSC #1 OSC #2
CSWIF
OSCCON1
WRITTEN
NOTE 1
ORDY
USER
CLEAR
Rev. 30-000065A
4/6/2017
Note: 
1. CSWIF is asserted coincident with NOSCR, and may be cleared before or after clearing
CSWHOLD = 0.
Figure 4-8. Clock Switch Abandoned
CSWHOLD
NOSCR
OSC #1
CSWIF
OSCCON1
WRITTEN
NOTE 1
OSCCON1
WRITTEN
NOTE 2
ORDY
Rev. 30-000066A
4/6/2017
Note: 
1. CSWIF may be cleared before or after rewriting OSCCON1; CSWIF is not automatically cleared.
2. ORDY = 0 if OSCCON1 does not match OSCCON2; a new switch will begin.
4.4 Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) allows the device to continue operating should the external oscillator
fail. The FSCM is enabled by setting the FCMEN bit in the Configuration Words. The FSCM is applicable
to all external Oscillator modes (LP, XT, HS, ECL/M/H and Secondary Oscillator).
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 53
Figure 4-9. FSCM Block Diagram
External
LFINTOSC ÷ 64
S
R
Q
31 kHz
(~32 us)
488 Hz
(~2 ms)
Clock Monitor
Latch
Clock
Failure
Detected
Oscillator
Clock
Q
Sample Clock
Rev. 30-000067A
4/6/2017
4.4.1 Fail-Safe Detection
The FSCM module detects a failed oscillator by comparing the external oscillator to the FSCM sample
clock. The sample clock is generated by dividing the LFINTOSC by 64. See Figure 4-9. Inside the fail
detector block is a latch. The external clock sets the latch on each falling edge of the external clock. The
sample clock clears the latch on each rising edge of the sample clock. A failure is detected when an
entire half-cycle of the sample clock elapses before the external clock goes low.
4.4.2 Fail-Safe Operation
When the external clock fails, the FSCM overwrites the COSC bits to select HFINTOSC (3'b110). The
frequency of HFINTOSC would be determined by the previous state of the HFFRQ bits and the NDIV/
CDIV bits. The bit flag OSCFIF of the PIR1 register is set. Setting this flag will generate an interrupt if the
OSCFIE bit of the PIE1 register is also set. The device firmware can then take steps to mitigate the
problems that may arise from a failed clock. The system clock will continue to be sourced from the
internal clock source until the device firmware successfully restarts the external oscillator and switches
back to external operation, by writing to the NOSC and NDIV bits.
4.4.3 Fail-Safe Condition Clearing
The Fail-Safe condition is cleared after a Reset, executing a SLEEP instruction or changing the NOSC
and NDIV bits. When switching to the external oscillator or PLL, the OST is restarted. While the OST is
running, the device continues to operate from the INTOSC selected in OSCCON1. When the OST times
out, the Fail-Safe condition is cleared after successfully switching to the external clock source. The
OSCFIF bit should be cleared prior to switching to the external clock source. If the Fail-Safe condition still
exists, the OSCFIF flag will again become set by hardware.
4.4.4 Reset or Wake-up from Sleep
The FSCM is designed to detect an oscillator failure after the Oscillator Start-up Timer (OST) has expired.
The OST is used after waking up from Sleep and after any type of Reset. The OST is not used with the
EC Clock modes so that the FSCM will be active as soon as the Reset or wake-up has completed.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 54
Figure 4-10. FSCM Timing Diagram
OSCFIF
System
Clock
Output
Sample Clock
Failure
Detected
Oscillator
Failure
(Q)
Test Test Test
Clock Monitor Output
Rev. 30-000068A
4/6/2017
Note:  The system clock is normally at a much higher frequency than the sample clock. The relative
frequencies in this example have been chosen for clarity.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 55
4.5 Register Summary - OSC
Address Name Bit Pos.
0x0ED3 OSCCON1 7:0 NOSC[2:0] NDIV[3:0]
0x0ED4 OSCCON2 7:0 COSC[2:0] CDIV[3:0]
0x0ED5 OSCCON3 7:0 CSWHOLD SOSCPWR ORDY NOSCR
0x0ED6 OSCSTAT 7:0 EXTOR HFOR MFOR LFOR SOR ADOR PLLR
0x0ED7 OSCEN 7:0 EXTOEN HFOEN MFOEN LFOEN SOSCEN ADOEN
0x0ED8 OSCTUNE 7:0 HFTUN[5:0]
0x0ED9 OSCFRQ 7:0 HFFRQ[3:0]
4.6 Register Definitions: Oscillator Control
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 56
4.6.1 OSCCON1
Name:  OSCCON1
Address:  0xED3
Oscillator Control Register1
Bit 7 6 5 4 3 2 1 0
NOSC[2:0] NDIV[3:0]
Access R/W R/W R/W R/W R/W R/W R/W
Reset f f f f f f f
Bits 6:4 – NOSC[2:0]  New Oscillator Source Request bits(1,2,3)
The setting requests a source oscillator and PLL combination per Table 4-2.
Table 4-1. Default Oscillator Settings
CONFIG1[RSTOSC]
SFR Reset Values (fff ffff)
Initial FOSC Frequency
NOSC/COSC NDIV/CDIV OSCFRQ
111 111 0000
4 MHz
EXTOSC per FEXTOSC
110 110 0010 FOSC = 1 MHz (4 MHz/4)
101 101 0000 LFINTOSC
100 100 0000 SOSC
011 Reserved
010 010 0000 4 MHz EXTOSC + 4xPLL(4)
001 Reserved
000 110 0000 64 MHz FOSC = 64 MHz
Table 4-2. NOSC Bit Settings
NOSC<2:0> Clock Source
111 EXTOSC(5)
110 HFINTOSC(6)
101 LFINTOSC
100 SOSC
011 Reserved
010 EXTOSC + 4x PLL(7)
001 Reserved
000 Reserved
Bits 3:0 – NDIV[3:0]  New Divider Selection Request bits(2,3)
The setting determines the new postscaler division ratio per Table 4-3.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 57
Table 4-3. NDIV Bit Settings
NDIV<3:0> Clock Divider
1111-1010 Reserved
1001 512
1000 256
0111 128
0110 64
0101 32
0100 16
0011 8
0010 4
0001 2
0000 1
Note: 
1. The default value (f/f) is determined by the CONFIG1[RSTOSC] Configuration bits. See Table 4-1.
2. If NOSC is written with a reserved value (Table 4-2), the operation is ignored and NOSC is not
written.
3. When CONFIG1[CSWEN] = 0, this register is read-only and cannot be changed from the POR
value.
4. EXTOSC must meet the PLL specifications.
5. EXTOSC configured by CONFIG1[FEXTOSC].
6. HFINTOSC frequency is set with the HFFRQ bits.
7. EXTOSC must meet the PLL specifications.
Related Links
3.7.1 CONFIG1
39.4.3 PLL Specifications
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
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4.6.2 OSCCON2
Name:  OSCCON2
Address:  0xED4
Oscillator Control Register 2
Bit 7 6 5 4 3 2 1 0
COSC[2:0] CDIV[3:0]
Access R R R R R R R
Reset q q q q q q q
Bits 6:4 – COSC[2:0]  Current Oscillator Source Select bits (read-only)(1,2)
Indicates the current source oscillator and PLL combination as shown in the following table.
Table 4-4. COSC Bit Settings
COSC/NOSC Clock Source
111 EXTOSC(3)
110 HFINTOSC(4)
101 LFINTOSC
100 SOSC
011 Reserved
010 EXTOSC + 4x PLL(5)
001 Reserved
000 Reserved
Bits 3:0 – CDIV[3:0]  Current Divider Select bits (read-only)(1,2)
Indicates the current postscaler division ratio as shown in the follwing table.
Table 4-5. CDIV Bit Settings
CDIV/NDIV Clock Divider
1111-1010 Reserved
1001 512
1000 256
0111 128
0110 64
0101 32
0100 16
0011 8
0010 4
0001 2
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
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...........continued
CDIV/NDIV Clock Divider
0000 1
Note: 
1. The POR value is the value present when user code execution begins.
2. The Reset value (q/q) is the same as the NOSC/NDIV bits.
3. EXTOSC configured by the CONFIG1[FEXTOSC] bits.
4. HFINTOSC frequency is set with the HFFRQ bits.
5. EXTOSC must meet the PLL specifications.
Related Links
3.7.1 CONFIG1
39.4.3 PLL Specifications
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
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4.6.3 OSCCON3
Name:  OSCCON3
Address:  0xED5
Oscillator Control Register 3
Bit 7 6 5 4 3 2 1 0
CSWHOLD SOSCPWR ORDY NOSCR
Access R/W/HC R/W RO RO
Reset 0 0 0 0
Bit 7 – CSWHOLD Clock Switch Hold bit
Value Description
1Clock switch will hold (with interrupt) when the oscillator selected by NOSC is ready
0Clock switch may proceed when the oscillator selected by NOSC is ready; when NOSCR
becomes ‘1’, the switch will occur
Bit 6 – SOSCPWR Secondary Oscillator Power Mode Select bit
Value Description
1Secondary oscillator operating in High-Power mode
0Secondary oscillator operating in Low-Power mode
Bit 4 – ORDY Oscillator Ready bit (read-only)
Value Description
1OSCCON1 = OSCCON2; the current system clock is the clock specified by NOSC
0A clock switch is in progress
Bit 3 – NOSCR  New Oscillator is Ready bit (read-only)(1)
Value Description
1A clock switch is in progress and the oscillator selected by NOSC indicates a ready condition
0A clock switch is not in progress, or the NOSC-selected oscillator is not yet ready
Note: 
1. If CSWHOLD = 0, the user may not see this bit set because the bit is set for less than one
instruction cycle.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 61
4.6.4 OSCSTAT
Name:  OSCSTAT
Address:  0xED6
Oscillator Status Register 1
Bit 7 6 5 4 3 2 1 0
EXTOR HFOR MFOR LFOR SOR ADOR PLLR
Access RO RO RO RO RO RO RO
Reset q q q q q q q
Bit 7 – EXTOR EXTOSC (external) Oscillator Ready bit
Value Description
1The oscillator is ready to be used
0The oscillator is not enabled, or is not yet ready to be used
Bit 6 – HFOR HFINTOSC Oscillator Ready bit
Value Description
1The oscillator is ready to be used
0The oscillator is not enabled, or is not yet ready to be used
Bit 5 – MFOR MFINTOSC Oscillator Ready bit
Value Description
1The oscillator is ready to be used
0The oscillator is not enabled, or is not yet ready to be used
Bit 4 – LFOR LFINTOSC Oscillator Ready bit
Value Description
1The oscillator is ready to be used
0The oscillator is not enabled, or is not yet ready to be used
Bit 3 – SOR Secondary (Timer1) Oscillator Ready bit
Value Description
1The oscillator is ready to be used
0The oscillator is not enabled, or is not yet ready to be used
Bit 2 – ADOR ADC Oscillator Ready bit
Value Description
1The oscillator is ready to be used
0The oscillator is not enabled, or is not yet ready to be used
Bit 0 – PLLR PLL Ready bit
Value Description
1The PLL is ready to be used
0The PLL is not enabled, the required input source is not ready, or the PLL is not locked.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 62
4.6.5 OSCFRQ
Name:  OSCFRQ
Address:  0xED9
HFINTOSC Frequency Selection Register
Bit 7 6 5 4 3 2 1 0
HFFRQ[3:0]
Access R/W R/W R/W R/W
Reset q q q q
Bits 3:0 – HFFRQ[3:0] HFINTOSC Frequency Selection bits
HFFRQ Nominal Freq (MHz)
1001
Reserved
1010
1111
1110
1101
1100
1011
1000(1) 64
0111 48
0110 32
0101 16
0100 12
0011 8
0010(1) 4
0001 2
0000 1
Note: 
1. Refer to Table 4-1 for more information.
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 63
4.6.6 OSCTUNE
Name:  OSCTUNE
Address:  0xED8
HFINTOSC Tuning Register
Bit 7 6 5 4 3 2 1 0
HFTUN[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bits 5:0 – HFTUN[5:0] HFINTOSC Frequency Tuning bits
Value Description
01 1111 Maximum frequency
00 0000 Center frequency. Oscillator module is running at the calibrated frequency (default value).
10 0000 Minimum frequency
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 64
4.6.7 OSCEN
Name:  OSCEN
Address:  0xED7
Oscillator Manual Enable Register
Bit 7 6 5 4 3 2 1 0
EXTOEN HFOEN MFOEN LFOEN SOSCEN ADOEN
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 7 – EXTOEN External Oscillator Manual Request Enable bit
Value Description
1EXTOSC is explicitly enabled, operating as specified by CONFIG1[FEXTOSC]
0EXTOSC is only enabled if requested by a peripheral
Bit 6 – HFOEN HFINTOSC Oscillator Manual Request Enable bit
Value Description
1HFINTOSC is explicitly enabled, operating as specified by OSCFRQ
0HFINTOSC is only enabled if requested by a peripheral
Bit 5 – MFOEN MFINTOSC (500 kHz/31.25 kHz) Oscillator Manual Request Enable bit (Derived from
HFINTOSC)
Value Description
1MFINTOSC is explicitly enabled
0MFINTOSC is only enabled if requested by a peripheral
Bit 4 – LFOEN LFINTOSC (31 kHz) Oscillator Manual Request Enable bit
Value Description
1LFINTOSC is explicitly enabled
0LFINTOSC is only enabled if requested by a peripheral
Bit 3 – SOSCEN Secondary Oscillator Manual Request Enable bit
Value Description
1Secondary Oscillator is explicitly enabled, operating as specified by SOSCPWR
0Secondary Oscillator is only enabled if requested by a peripheral
Bit 2 – ADOEN ADC Oscillator Manual Request Enable bit
Value Description
1ADC oscillator is explicitly enabled
0ADC oscillator is only enabled if requested by a peripheral
PIC18F26/45/46Q10
Oscillator Module (with Fail-Safe Clock Monitor)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 65
5. Reference Clock Output Module
The reference clock output module provides the ability to send a clock signal to the clock reference output
pin (CLKR). The reference clock output can also be routed internally as a signal for other peripherals,
such as the Data Signal Modulator (DSM), memory scanner, and timer module.
The reference clock output module has the following features:
Selectable Clock Source Using the CLKRCLK Register
Programmable Clock Divider
Selectable Duty Cycle
Figure 5-1. Clock Reference Block Diagram
Filename: 10-000261B.vsd
Title: Clock Reference Block Diagram With Selectable Clock Source
Last Edit: 5/11/2016
First Used: PIC18(L)F2x/4x/6xK40 (MVAF,MVAE,MVAB,MVAC,MVAK)
Notes:
Rev. 10-000261B
5/11/2016
000
011
010
001
100
101
110
111
128
64
32
16
8
4
2
EN
DIV
Counter Reset
Duty Cycle PPS
To Peripherals
CLKR
CLK
See
CLKRCLK
Register
EN
Reference Clock Divider
DC RxyPPS
Figure 5-2. Clock Reference Timing
Filename: 10-000264B.vsd
Title: Clock Reference Timing
Last Edit: 5/25/2016
First Used: PIC18(L)F2x/4x/6xK40 (MVAF,MVAE,MVAB,MVAC,MVAK)
Notes:
Rev. 10-000264B
5/25/2016
CLKRCLK
CLKREN
CLKRDIV<2:0> = 001
CLKRDC<1:0> = 10
CLKR Output
Duty Cycle
(50%)
CLKRDIV<2:0> = 001
CLKRDC<1:0> = 01
CLKR Output
Duty Cycle
(25%)
CLKRCLK/2
P1 P2
PIC18F26/45/46Q10
Reference Clock Output Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 66
5.1 Clock Source
The clock source of the reference clock peripheral is selected with the CLK bits. The available clock
sources are listed in the following table:
Table 5-1. CLKR Clock Sources
CLK Clock Source
1111 LC8_out
1110 LC7_out
1101 LC6_out
1100 LC5_out
1011 LC4_out
1010 LC3_out
1001 LC2_out
1000 LC1_out
0111-0101 0101
0100 SOSC
0011 MFINTOSC (500 kHz)
0010 LFINTOSC (31 kHz)
0001 HFINTOSC
0000 FOSC
5.1.1 Clock Synchronization
The CLKR output signal is ensured to be glitch-free when the EN bit is set to start the module and enable
the CLKR output.
When the reference clock output is disabled, the output signal will be disabled immediately.
Clock dividers and clock duty cycles can be changed while the module is enabled but doing so may
cause glitches to occur on the output. To avoid possible glitches, clock dividers and clock duty cycles
should be changed only when the EN bit is clear.
5.2 Programmable Clock Divider
The module takes the clock input and divides it based on the value of the DIV bits.
The following configurations are available:
Base FOSC value
FOSC divided by 2
FOSC divided by 4
FOSC divided by 8
FOSC divided by 16
PIC18F26/45/46Q10
Reference Clock Output Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 67
FOSC divided by 32
FOSC divided by 64
FOSC divided by 128
The clock divider values can be changed while the module is enabled. However, in order to prevent
glitches on the output, the DIV bits should only be changed when the module is disabled (EN = 0).
5.3 Selectable Duty Cycle
The DC bits are used to modify the duty cycle of the output clock. A duty cycle of 0%, 25%, 50%, or 75%
can be selected for all clock rates when the DIV value is not 0b000. When DIV=0b000 then the duty
cycle defaults to 50% for all values of DC except 0b00 in which case the duty cycle is 0% (constant low
output).
The duty cycle can be changed while the module is enabled. However, in order to prevent glitches on the
output, the DC bits should only be changed when the module is disabled (EN = 0).
Important:  The DC value at reset is 10. This makes the default duty cycle 50% and not 0%.
5.4 Operation in Sleep Mode
The reference clock module continues to operate and provide a signal output in Sleep for all clock source
selections except FOSC (CLK=0).
PIC18F26/45/46Q10
Reference Clock Output Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 68
5.5 Register Summary: Reference CLK
Address Name Bit Pos.
0x0F39 CLKRCON 7:0 EN DC[1:0] DIV[2:0]
0x0F3A CLKRCLK 7:0 CLK[3:0]
5.6 Register Definitions: Reference Clock
Long bit name prefixes for the Reference Clock peripherals are shown in the following table. Refer to the
"Long Bit Names" section for more information.
Table 5-2. TABLE 5-1:
Peripheral Bit Name Prefix
CLKR CLKR
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
Reference Clock Output Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 69
5.6.1 CLKRCON
Name:  CLKRCON
Address:  0xF39
Reference Clock Control Register
Bit 7 6 5 4 3 2 1 0
EN DC[1:0] DIV[2:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 1 0 0 0 0
Bit 7 – EN
Reference Clock Module Enable bit
Value Description
1Reference clock module enabled
0Reference clock module is disabled
Bits 4:3 – DC[1:0]
Reference Clock Duty Cycle bits(1)
Value Description
11 Clock outputs duty cycle of 75%
10 Clock outputs duty cycle of 50%
01 Clock outputs duty cycle of 25%
00 Clock outputs duty cycle of 0%
Bits 2:0 – DIV[2:0]
Reference Clock Divider bits
Value Description
111 Base clock value divided by 128
110 Base clock value divided by 64
101 Base clock value divided by 32
100 Base clock value divided by 16
011 Base clock value divided by 8
010 Base clock value divided by 4
001 Base clock value divided by 2
000 Base clock value
Note: 
1. Bits are valid for reference clock divider values of two or larger, the base clock cannot be further
divided.
PIC18F26/45/46Q10
Reference Clock Output Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 70
5.6.2 CLKRCLK
Name:  CLKRCLK
Address:  0xF3A
Clock Reference Clock Selection MUX
Bit 7 6 5 4 3 2 1 0
CLK[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – CLK[3:0] CLKR Clock Selection bits
See the Clock Sources table.
PIC18F26/45/46Q10
Reference Clock Output Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 71
6. Power-Saving Operation Modes
The purpose of the Power-Down modes is to reduce power consumption. There are three Power-Down
modes:
Doze mode
Sleep mode
Idle mode
6.1 Doze Mode
Doze mode allows for power-saving by reducing CPU operation and program memory (PFM) access,
without affecting peripheral operation. Doze mode differs from Sleep mode because the band gap and
system oscillators continue to operate, while only the CPU and PFM are affected. The reduced execution
saves power by eliminating unnecessary operations within the CPU and memory.
When the Doze Enable bit is set (DOZEN = 1), the CPU executes only one instruction cycle out of every
N cycles as defined by the DOZE bits. For example, if DOZE = 001, the instruction cycle ratio is 1:4. The
CPU and memory execute for one instruction cycle and then lay idle for three instruction cycles. During
the unused cycles, the peripherals continue to operate at the system clock speed.
6.1.1 Doze Operation
The Doze operation is illustrated in Figure 6-1 . For this example:
Doze enabled (DOZEN = 1)
DOZE = 001 (1:4) ratio
Recover-on-Interrupt enabled (ROI = 1)
As with normal operation, the PFM fetches for the next instruction cycle. The Q-clocks to the peripherals
continue throughout.
Figure 6-1. DOZE MODE OPERATION EXAMPLE (DOZE<2:0> = 001, 1:4)
Rev. 3000089A
4/11/2017
6.1.2 Interrupts During Doze
If an interrupt occurs and the Recover-On-Interrupt bit is clear (ROI = 0) at the time of the interrupt, the
Interrupt Service Routine (ISR) continues to execute at the rate selected by DOZE<2:0>. Interrupt latency
is extended by the DOZE<2:0> ratio.
If an interrupt occurs and the ROI bit is set (ROI = 1) at the time of the interrupt, the DOZEN bit is cleared
and the CPU executes at full speed. The prefetched instruction is executed and then the interrupt vector
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 72
sequence is executed. In Figure 6-1, the interrupt occurs during the 2nd instruction cycle of the Doze
period, and immediately brings the CPU out of Doze. If the Doze-On-Exit (DOE) bit is set (DOE = 1) when
the RETFIE operation is executed, DOZEN is set, and the CPU executes at the reduced rate based on
the DOZE<2:0> ratio.
Figure 6-2. Doze Software Example
//Mainline operation
bool somethingToDo = FALSE:
void main()
{
initializeSystem();
// DOZE = 64:1 (for example)
// ROI = 1;
GIE = 1; // enable interrupts
while (1)
{
// If ADC completed, process data
if (somethingToDo)
{
doSomething();
DOZEN = 1; // resume low-power
}
}
}
// Data interrupt handler
void interrupt()
{
// DOZEN = 0 because ROI = 1
if (ADIF)
{
somethingToDo = TRUE;
DOE = 0; // make main() go fast
ADIF = 0;
}
// else check other interrupts...
if (TMR0IF)
{
timerTick++;
DOE = 1; // make main() go slow
TMR0IF = 0;
}
}
6.2 Sleep Mode
Sleep mode is entered by executing the SLEEP instruction, while the Idle Enable (IDLEN) bit of the
CPUDOZE register is clear (IDLEN = 0).
Upon entering Sleep mode, the following conditions exist:
1. WDT will be cleared but keeps running if enabled for operation during Sleep
2. The PD bit of the STATUS register is cleared
3. The TO bit of the STATUS register is set
4. The CPU clock is disabled
5. LFINTOSC, SOSC, HFINTOSC and ADCRC are unaffected and peripherals using them may
continue operation in Sleep.
6. I/O ports maintain the status they had before Sleep was executed (driving high, low, or high-
impedance)
7. Resets other than WDT are not affected by Sleep mode
Refer to individual chapters for more details on peripheral operation during Sleep.
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 73
To minimize current consumption, the following conditions should be considered:
I/O pins should not be floating
External circuitry sinking current from I/O pins
Internal circuitry sourcing current from I/O pins
Current draw from pins with internal weak pull-ups
Modules using any oscillator
I/O pins that are high-impedance inputs should be pulled to VDD or VSS externally to avoid switching
currents caused by floating inputs.
Examples of internal circuitry that might be sourcing current include modules such as the DAC and FVR
modules.
Related Links
31. (DAC) 5-Bit Digital-to-Analog Converter Module
29. (FVR) Fixed Voltage Reference
6.2.1 Wake-up from Sleep
The device can wake-up from Sleep through one of the following events:
1. External Reset input on MCLR pin, if enabled
2. BOR Reset, if enabled
3. Low-Power Brown-Out Reset (LPBOR), if enabled
4. POR Reset
5. Windowed Watchdog Timer, if enabled
6. All interrupt sources except clock switch interrupt can wake-up the part.
The first five events will cause a device Reset. The last one event is considered a continuation of
program execution. To determine whether a device Reset or wake-up event occurred, refer to the
"Determining the Cause of a Reset" section.
When the SLEEP instruction is being executed, the next instruction (PC + 2) is prefetched. For the device
to wake-up through an interrupt event, the corresponding Interrupt Enable bit must be enabled, as well as
the Peripheral Interrupt Enable bit (PEIE = 1), for every interrupt not in PIR0. Wake-up will occur
regardless of the state of the GIE bit. If the GIE bit is disabled, the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is enabled, the device executes the instruction after
the SLEEP instruction, the device will then call the Interrupt Service Routine. In cases where the
execution of the instruction following SLEEP is not desirable, the user should have a NOP after the SLEEP
instruction.
The WDT is cleared when the device wakes-up from Sleep, regardless of the source of wake-up.
Upon a wake from a Sleep event, the core will wait for a combination of three conditions before beginning
execution. The conditions are:
PFM Ready
COSC-Selected Oscillator Ready
BOR Ready (unless BOR is disabled)
Related Links
8.11 Determining the Cause of a Reset
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 74
6.2.2 Wake-up Using Interrupts
When global interrupts are disabled (GIE cleared) and any interrupt source, with the exception of the
clock switch interrupt, has both its interrupt enable bit and interrupt flag bit set, one of the following will
occur:
If the interrupt occurs before the execution of a SLEEP instruction
SLEEP instruction will execute as a NOP
WDT and WDT prescaler will not be cleared
TO bit of the STATUS register will not be set
PD bit of the STATUS register will not be cleared
If the interrupt occurs during or after the execution of a SLEEP instruction
SLEEP instruction will be completely executed
Device will immediately wake-up from Sleep
WDT and WDT prescaler will be cleared
TO bit of the STATUS register will be set
PD bit of the STATUS register will be cleared
Even if the flag bits were checked before executing a SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To determine whether a SLEEP instruction executed,
test the PD bit. If the PD bit is set, the SLEEP instruction was executed as a NOP.
Figure 6-3. WAKE-UP FROM SLEEP THROUGH INTERRUPT
CLKIN(1)
CLKOUT(2)
Interrupt flag
GIE bit
(INTCON reg.)
Instruction Flow
PC
Instruction
Fetched
Instruction
Executed
PC PC + 1 PC + 2
Inst(PC) = Sleep
Inst(PC - 1)
Inst(PC + 1)
Sleep
Processor in
Sleep
Interrupt Latency(4)
Inst(PC + 2)
Inst(PC + 1)
Inst(0004h) Inst(0005h)
Inst(0004h)
Forced NOP
PC + 2 0004h 0005h
Forced NOP
TOST(3)
PC + 2
Rev. 3000090A
4/12/2017
Note: 
1. External clock. High, Medium, Low mode assumed.
2. CLKOUT is shown here for timing reference.
3. TOST = 1024 TOSC. This delay does not apply to EC and INTOSC Oscillator modes.
4. GIE = 1 assumed. In this case after wake-up, the processor calls the ISR at 0004h. If GIE = 0,
execution will continue in-line.
6.2.3 Low-Power Sleep Mode
The PIC18F26/45/465Q10 device family contains an internal Low Dropout (LDO) voltage regulator, which
allows the device I/O pins to operate at voltages up to 5.5V while the internal device logic operates at a
lower voltage. The LDO and its associated reference circuitry must remain active when the device is in
Sleep mode.
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 75
The PIC18F26/45/465Q10devices allows the user to optimize the operating current in Sleep, depending
on the application requirements.
Low-Power Sleep mode can be selected by setting the VREGPM bit of the VREGCON register.
6.2.3.1 Sleep Current vs. Wake-up Time
In the default operating mode, the LDO and reference circuitry remain in the normal configuration while in
Sleep. The device is able to exit Sleep mode quickly since all circuits remain active. In Low-Power Sleep
mode, when waking-up from Sleep, an extra delay time is required for these circuits to return to the
normal configuration and stabilize.
The Low-Power Sleep mode is beneficial for applications that stay in Sleep mode for long periods of time.
The Normal mode is beneficial for applications that need to wake from Sleep quickly and frequently.
6.2.3.2 Peripheral Usage in Sleep
Some peripherals that can operate in Sleep mode will not operate properly with the Low-Power Sleep
mode selected. The Low-Power Sleep mode is intended for use with these peripherals:
Brown-out Reset (BOR)
Windowed Watchdog Timer (WWDT)
External interrupt pin/Interrupt-On-Change pins
Peripherals that run off external secondary clock source
It is the responsibility of the end user to determine what is acceptable for their application when setting
the VREGPM settings in order to ensure operation in Sleep.
6.3 Idle Mode
When IDLEN is set (IDLEN = 1), the SLEEP instruction will put the device into Idle mode. In Idle mode,
the CPU and memory operations are halted, but the peripheral clocks continue to run. This mode is
similar to Doze mode, except that in IDLE both the CPU and PFM are shut off.
Important:  If CLKOUTEN is enabled (CLKOUTEN = 0, Configuration Word 1H), the output will
continue operating while in Idle.
6.3.1 Idle and Interrupts
IDLE mode ends when an interrupt occurs (even if GIE = 0), but IDLEN is not changed. The device can
re-enter IDLE by executing the SLEEP instruction.
If Recover-on-Interrupt is enabled (ROI = 1), the interrupt that brings the device out of Idle also restores
full-speed CPU execution when doze is also enabled.
6.3.2 Idle and WWDT
When in Idle, the WWDT Reset is blocked and will instead wake the device. The WWDT wake-up is not
an interrupt, therefore ROI does not apply.
Important:  The WWDT can bring the device out of Idle, in the same way it brings the device
out of Sleep. The DOZEN bit is not affected.
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 76
6.4 Peripheral Operation in Power-Saving Modes
All selected clock sources and the peripherals running off them are active in both IDLE and DOZE mode.
Only in Sleep mode, both the FOSC and FOSC/4 clocks are unavailable. All the other clock sources are
active, if enabled manually or through peripheral clock selection before the part enters Sleep.
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 77
6.5 Register Summary - Power Savings Control
Address Name Bit Pos.
0x0ED2 CPUDOZE 7:0 IDLEN DOZEN ROI DOE DOZE[2:0]
0x0ED3
...
0x0ED9
Reserved
0x0EDA VREGCON 7:0 PMSYS[1:0] VREGPM[1:0]
6.6 Register Definitions: Power Savings Control
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 78
6.6.1 VREGCON
Name:  VREGCON
Address:  0xEDA
Note: 
1. System and peripheral inputs should not exceed 500 kHz in ULP mode.
Voltage Regulator Control Register
Bit 7 6 5 4 3 2 1 0
PMSYS[1:0] VREGPM[1:0]
Access RO RO R/W R/W
Reset g g 1 0
Bits 5:4 – PMSYS[1:0] System Power Mode Status bits
Value Description
11 Reserved
10 ULP regulator is active
01 Main regulator in LP mode is active
00 Main regulator in HP mode is active
Bits 1:0 – VREGPM[1:0] Voltage Regulator Power Mode Selection bit
Value Description
11 Reserved. Do not use.
10 ULP regulator(1)
01 Main regulator in LP mode
00 Main regulator in HP mode
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 79
6.6.2 CPUDOZE
Name:  CPUDOZE
Address:  0xED2
Doze and Idle Register
Bit 7 6 5 4 3 2 1 0
IDLEN DOZEN ROI DOE DOZE[2:0]
Access R/W R/W/HC/HS R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bit 7 – IDLEN Idle Enable bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1A SLEEP instruction inhibits the CPU clock, but not the peripheral clock(s)
0A SLEEP instruction places the device into full Sleep mode
Bit 6 – DOZEN
Doze Enable bit(1)
Value Description
1The CPU executes instruction cycles according to DOZE setting
0The CPU executes all instruction cycles (fastest, highest power operation)
Bit 5 – ROI Recover-On-Interrupt bit
Value Description
1Entering the Interrupt Service Routine (ISR) makes DOZEN = 0, bringing the CPU to full-
speed operation
0Interrupt entry does not change DOZEN
Bit 4 – DOE Doze-On-Exit bit
Value Description
1Executing RETFIE makes DOZEN = 1, bringing the CPU to reduced speed operation
0RETFIE does not change DOZEN
Bits 2:0 – DOZE[2:0] Ratio of CPU Instruction Cycles to Peripheral Instruction Cycles
Value Description
111 1:256
110 1:128
101 1:64
100 1:32
011 1:16
010 1:8
001 1:4
000 1:2
Note: 
1. When ROI = 1 or DOE = 1, DOZEN is changed by hardware interrupt entry and/or exit.
PIC18F26/45/46Q10
Power-Saving Operation Modes
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 80
7. (PMD) Peripheral Module Disable
This module provides the ability to selectively enable or disable a peripheral. Disabling a peripheral
places it in its lowest possible power state. The user can disable unused modules to reduce the overall
power consumption.
The PIC18F26/45/46Q10 devices address this requirement by allowing peripheral modules to be
selectively enabled or disabled. Disabling a peripheral places it in the lowest possible power mode.
Important:  All modules are ON by default following any system Reset.
7.1 Disabling a Module
A peripheral can be disabled by setting the corresponding peripheral disable bit in the PMDx register.
Disabling a module has the following effects:
The module is held in Reset and does not function.
All the SFRs pertaining to that peripheral become “unimplemented”
Writing is disabled
Reading returns 0x00
Module outputs are disabled
Related Links
15.1 I/O Priorities
7.2 Enabling a Module
Clearing the corresponding module disable bit in the PMDx register, re-enables the module and the SFRs
will reflect the Power-on Reset values.
Important:  There should be no reads/writes to the module SFRs for at least two instruction
cycles after it has been re-enabled.
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 81
7.3 Register Summary - PMD
Address Name Bit Pos.
0x0EDC PMD0 7:0 SYSCMD FVRMD HLVDMD CRCMD SCANMD NVMMD CLKRMD IOCMD
0x0EDD PMD1 7:0 TMR6MD TMR5MD TMR4MD TMR3MD TMR2MD TMR1MD TMR0MD
0x0EDE PMD2 7:0 DACMD ADCMD CMP2MD CMP1MD ZCDMD
0x0EDF PMD3 7:0 CLC8MD CLC7MD CLC6MD CLC5MD PWM4MD PWM3MD CCP2MD CCP1MD
0x0EE0 PMD4 7:0 UART2MD UART1MD MSSP2MD MSSP1MD CWG1MD
0x0EE1 PMD5 7:0 CLC4MD CLC3MD CLC2MD CLC1MD DSMMD
7.4 Register Definitions: Peripheral Module Disable
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 82
7.4.1 PMD0
Name:  PMD0
Address:  0xEDC
PMD Control Register 0
Bit 7 6 5 4 3 2 1 0
SYSCMD FVRMD HLVDMD CRCMD SCANMD NVMMD CLKRMD IOCMD
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – SYSCMD Disable Peripheral System Clock Network bit
Disables the System clock network(1)
Value Description
1System clock network disabled (FOSC)
0System clock network enabled
Bit 6 – FVRMD Disable Fixed Voltage Reference bit
Value Description
1FVR module disabled
0FVR module enabled
Bit 5 – HLVDMD Disable High-Low-Voltage Detect bit
Value Description
1HLVD module disabled
0HLVD module enabled
Bit 4 – CRCMD Disable CRC Engine bit
Value Description
1CRC module disabled
0CRC module enabled
Bit 3 – SCANMD Disable NVM Memory Scanner bit
Disables the Scanner module(2)
Value Description
1NVM Memory Scan module disabled
0NVM Memory Scan module enabled
Bit 2 – NVMMD NVM Module Disable bit
Disables the NVM module(3)
Value Description
1All Memory reading and writing is disabled; NVMCON registers cannot be written
0NVM module enabled
Bit 1 – CLKRMD Disable Clock Reference bit
Value Description
1CLKR module disabled
0CLKR module enabled
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 83
Bit 0 – IOCMD Disable Interrupt-on-Change bit, All Ports
Value Description
1IOC module(s) disabled
0IOC module(s) enabled
Note: 
1. Clearing the SYSCMD bit disables the system clock (FOSC) to peripherals, however peripherals
clocked by FOSC/4 are not affected.
2. Subject to SCANE bit in Configuration Word 4.
3. When enabling NVM, a delay of up to 1 µs is required before accessing data.
Related Links
3.7.4 CONFIG4
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 84
7.4.2 PMD1
Name:  PMD1
Address:  0xEDD
PMD Control Register 1
Bit 7 6 5 4 3 2 1 0
TMR6MD TMR5MD TMR4MD TMR3MD TMR2MD TMR1MD TMR0MD
Access R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6 – TMRnMD Disable Timer n bit
Value Description
1TMRn module disabled
0TMRn module enabled
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 85
7.4.3 PMD2
Name:  PMD2
Address:  0xEDE
PMD Control Register 2
Bit 7 6 5 4 3 2 1 0
DACMD ADCMD CMP2MD CMP1MD ZCDMD
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bit 6 – DACMD Disable DAC bit
Value Description
1DAC module disabled
0DAC module enabled
Bit 5 – ADCMD Disable ADC bit
Value Description
1ADC module disabled
0ADC module enabled
Bits 1, 2 – CMPnMD Disable Comparator CMPn bit
Value Description
1CMPn module disabled
0CMPn module enabled
Bit 0 – ZCDMD  Disable Zero-Cross Detect module bit(1)
Value Description
1ZCD module disabled
0ZCD module enabled
Note: 
1. Subject to ZCD bit in Configuration Word 2.
Related Links
3.7.2 CONFIG2
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 86
7.4.4 PMD3
Name:  PMD3
Address:  0xEDF
PMD Control Register 3
Bit 7 6 5 4 3 2 1 0
CLC8MD CLC7MD CLC6MD CLC5MD PWM4MD PWM3MD CCP2MD CCP1MD
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 4, 5, 6, 7 – CLCnMD Disable CLCn bit
Value Description
1CLCn module disabled
0CLCn module enabled
Bits 2, 3 – PWMnMD Disable PWMn bit
Value Description
1PWMn module disabled
0PWMn module enabled
Bits 0, 1 – CCPnMD Disable Capture/Compare/PWMn bit
Value Description
1CCPn module disabled
0CCPn module enabled
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 87
7.4.5 PMD4
Name:  PMD4
Address:  0xEE0
PMD Control Register 4
Bit 7 6 5 4 3 2 1 0
UART2MD UART1MD MSSP2MD MSSP1MD CWG1MD
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 6, 7 – UARTnMD Disable EUSARTn bit
Value Description
1EUSARTn module disabled
0EUSARTn module enabled
Bits 4, 5 – MSSPnMD Disable MSSPn bit
Value Description
1MSSPn module disabled
0MSSPn module enabled
Bit 0 – CWG1MD Disable CWG1 Module bit
Value Description
1CWG1 module disabled
0CWG1 module enabled
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 88
7.4.6 PMD5
Name:  PMD5
Address:  0xEE1
PMD Control Register 5
Bit 7 6 5 4 3 2 1 0
CLC4MD CLC3MD CLC2MD CLC1MD DSMMD
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4, 5, 6, 7 – CLCnMD Disable CLCn bit
Value Description
1CLCn module disabled
0CLCn module enabled
Bit 0 – DSMMD Disable DSM bit
Value Description
1DSM module disabled
0DSM module enabled
PIC18F26/45/46Q10
(PMD) Peripheral Module Disable
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 89
8. Resets
There are multiple ways to reset this device:
Power-on Reset (POR)
Brown-out Reset (BOR)
Low-Power Brown-out Reset (LPBOR)
MCLR Reset
WDT Reset
RESET instruction
Stack Overflow
Stack Underflow
Programming mode exit
To allow VDD to stabilize, an optional Power-up Timer can be enabled to extend the Reset time after a
BOR or POR event.
A simplified block diagram of the On-Chip Reset Circuit is shown in the block diagram below.
Figure 8-1. Simplified Block Diagram of On-Chip Reset Circuit
Filename: 10-000006E.vsd
Title: Simplified block diagram for RESET module
Last Edit: 5/11/2016
First Used: PIC18(L)F2x/4x/6xK40 (MVAF,MVAE,MVAB,MVAC,MVAK)
Note: 1. See Table 8-1 for BOR active conditions
Device
Reset
Power-on
Reset
WWDT Time-out/
Window voilation
Brown-out
Reset(1)
LPBOR
Reset
RESET Instruction
MCLRE
PWRTE
LFINTOSC
VDD
ICSP™ Programming Mode Exit
Stack Underflow
Stack Overflow
RPower-up
Timer
Rev. 10-000006E
5/11/2016
VPP/MCLR
Note:  See “BOR Operating Conditions” table for BOR active conditions.
8.1 Power-on Reset (POR)
The POR circuit holds the device in Reset until VDD has reached an acceptable level for minimum
operation. Slow rising VDD, fast operating speeds or analog performance may require greater than
minimum VDD. The PWRT, BOR or MCLR features can be used to extend the start-up period until all
device operation conditions have been met.
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 90
8.2 Brown-out Reset (BOR)
The BOR circuit holds the device in Reset when VDD reaches a selectable minimum level. Between the
POR and BOR, complete voltage range coverage for execution protection can be implemented.
The Brown-out Reset module has four operating modes controlled by the BOREN<1:0> bits in
Configuration Words. The four operating modes are:
BOR is always on
BOR is off when in Sleep
BOR is controlled by software
BOR is always off
Refer to “BOR Operating Conditions” table for more information.
The Brown-out Reset voltage level is selectable by configuring the BORV<1:0> bits in Configuration
Words.
A VDD noise rejection filter prevents the BOR from triggering on small events. If VDD falls below VBOR for a
duration greater than parameter TBORDC, the device will reset.
Related Links
3.7.2 CONFIG2
39.4.5 Reset, WDT, Oscillator Start-up Timer, Power-up Timer, Brown-Out Reset and Low-Power Brown-
Out Reset Specifications
8.2.1 BOR is Always On
When the BOREN bits of Configuration Words are programmed to ‘11’, the BOR is always on. The device
start-up will be delayed until the BOR is ready and VDD is higher than the BOR threshold.
BOR protection is active during Sleep. The BOR does not delay wake-up from Sleep.
8.2.2 BOR is OFF in Sleep
When the BOREN bits of Configuration Words are programmed to ‘10’, the BOR is on, except in Sleep.
The device start-up will be delayed until the BOR is ready and VDD is higher than the BOR threshold.
BOR protection is not active during Sleep. The device wake-up will be delayed until the BOR is ready.
8.2.3 BOR Controlled by Software
When the BOREN bits of Configuration Words are programmed to ‘01’, the BOR is controlled by the
SBOREN bit. The device start-up is not delayed by the BOR ready condition or the VDD level.
BOR protection begins as soon as the BOR circuit is ready. The status of the BOR circuit is reflected in
the BORRDY bit.
BOR protection is unchanged by Sleep.
Table 8-1. BOR Operating Modes
BOREN<1:0> SBOREN Device
Mode BOR Mode
Instruction Execution upon:
Release of POR Wake-up from Sleep
11 X X Active Wait for release of BOR
(BORRDY = 1)Begins immediately
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 91
...........continued
BOREN<1:0> SBOREN Device
Mode BOR Mode
Instruction Execution upon:
Release of POR Wake-up from Sleep
10 X
Awake Active Wait for release of BOR
(BORRDY = 1)N/A
Sleep Hibernate N/A Wait for release of
BOR (BORRDY = 1)
01
1 X Active Wait for release of BOR
(BORRDY = 1)Begins immediately
0 X Hibernate
00 X X Disabled Begins immediately
Note: 
1. In this specific case, “Release of POR” and “Wake-up from Sleep”, there is no delay in start-up. The
BOR ready flag, (BORRDY = 1), will be set before the CPU is ready to execute instructions
because the BOR circuit is forced on by the BOREN<1:0> bits
Figure 8-2. Brown-out Situations
TPWRT(1)
VBOR
VDD
Internal
Reset
VBOR
VDD
Internal
Reset TPWRT(1)
< TPWRT
TPWRT(1)
VBOR
VDD
Internal
Reset
Rev. 30-000092A
4/12/2017
Note:  TPWRT delay only if PWRTE bit is programmed to ‘0’.
8.2.4 BOR and Bulk Erase
BOR is forced ON during PFM Bulk Erase operations to make sure that the system code protection
cannot be compromised by reducing VDD.
During Bulk Erase, the BOR is enabled at 1.9V, even if it is configured to some other value. If VDD falls,
the erase cycle will be aborted, but the device will not be reset.
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 92
8.3 Low-Power Brown-out Reset (LPBOR)
The Low-Power Brown-out Reset (LPBOR) provides an additional BOR circuit for low-power operation.
Refer to the figure below to see how the BOR interacts with other modules.
The LPBOR is used to monitor the external VDD pin. When too low of a voltage is detected, the device is
held in Reset.
Figure 8-3. LPBOR, BOR, POR Relationship
Reset
POR
logic
LPBOR
To PCON
indicator bit
BOR
BOR Event
REARM POR
Event
POR Event LPBOR Event
Any Reset
Rev. 30-000091B
6/21/2017
8.3.1 Enabling LPBOR
The LPBOR is controlled by the LPBOREN bit of Configuration Word 2. When the device is erased, the
LPBOR module defaults to disabled.
Related Links
3.7.2 CONFIG2
8.3.1.1 LPBOR Module Output
The output of the LPBOR module is a signal indicating whether or not a Reset is to be asserted. This
signal is OR’d together with the Reset signal of the BOR module to provide the generic BOR signal,
which goes to the PCON0 register and to the power control block.
8.4 MCLR Reset
The MCLR is an optional external input that can reset the device. The MCLR function is controlled by the
MCLRE bit of Configuration Words and the LVP bit of Configuration Words (see table below). The
RMCLR bit in the PCON0 register will be set to ‘0’ if a MCLR has occurred.
Table 8-2. MCLR Configuration
MCLRE LVP MCLR
x 1 Enabled
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 93
...........continued
MCLRE LVP MCLR
1 0 Enabled
0 0 Disabled
8.4.1 MCLR Enabled
When MCLR is enabled and the pin is held low, the device is held in Reset. The MCLR pin is connected
to VDD through an internal weak pull-up.
The device has a noise filter in the MCLR Reset path. The filter will detect and ignore small pulses.
Important:  An internal Reset event (RESET instruction, BOR, WWDT, POR, STKOVF,
STKUNF) does not drive the MCLR pin low.
8.4.2 MCLR Disabled
When MCLR is disabled, the MCLR becomes input-only and pin functions such as internal weak pull-ups
are under software control.
Related Links
15.1 I/O Priorities
8.5 Windowed Watchdog Timer (WWDT) Reset
The Windowed Watchdog Timer generates a Reset if the firmware does not issue a CLRWDT instruction
within the time-out period or window set. The TO and PD bits in the STATUS register and the RWDT bit
are changed to indicate a WDT Reset. The WDTWV bit indicates if the WDT Reset has occurred due to a
time-out or a window violation.
Related Links
10.8.5 STATUS
9. (WWDT) Windowed Watchdog Timer
8.6 RESET Instruction
A RESET instruction will cause a device Reset. The RI bit will be set to ‘0’. See Table 8-3 for default
conditions after a RESET instruction has occurred.
8.7 Stack Overflow/Underflow Reset
The device can reset when the Stack Overflows or Underflows. The STKOVF or STKUNF bits register
indicate the Reset condition. These Resets are enabled by setting the STVREN bit in Configuration
Words.
Related Links
3.7.2 CONFIG2
10.1.2.3 Stack Overflow and Underflow Resets
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 94
8.8 Programming Mode Exit
Upon exit of Programming mode, the device will behave as if a POR had just occurred.
8.9 Power-up Timer (PWRT)
The Power-up Timer provides a nominal 66 ms (2048 cycles of LFINTOSC) time-out on POR or Brown-
out Reset.
The device is held in Reset as long as PWRT is active. The PWRT delay allows additional time for the
VDD to rise to an acceptable level. The Power-up Timer is enabled by clearing the PWRTE bit in
Configuration Words.
The Power-up Timer starts after the release of the POR and BOR.
For additional information, refer to Application Note AN607, “Power-up Trouble Shooting” (DS00000607).
8.10 Start-up Sequence
Upon the release of a POR or BOR, the following must occur before the device will begin executing:
1. Power-up Timer runs to completion (if enabled).
2. Oscillator Start-up Timer runs to completion (if required for selected oscillator source).
3. MCLR must be released (if enabled).
The total time-out will vary based on oscillator configuration and Power-up Timer configuration.
The Power-up Timer and Oscillator Start-up Timer run independently of MCLR Reset. If MCLR is kept low
long enough, the Power-up Timer and Oscillator Start-up Timer will expire. Upon bringing MCLR high, the
device will begin execution after 10 FOSC cycles (see figure below). This is useful for testing purposes or
to synchronize more than one device operating in parallel.
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 95
Figure 8-4. Reset Start-up Sequence
TOST
TMCLR
TPWRT
VDD
Internal POR
Power-up Timer
MCLR
Internal RESET
Oscillator Modes
Oscillator Start-up Timer
Oscillator
FOSC
Internal Oscillator
Oscillator
FOSC
External Clock (EC)
CLKIN
FOSC
External Crystal
Rev. 30-000093A
4/12/2017
Related Links
4. Oscillator Module (with Fail-Safe Clock Monitor)
8.11 Determining the Cause of a Reset
Upon any Reset, multiple bits in the STATUS and PCON0 registers are updated to indicate the cause of
the Reset. The following table shows the Reset conditions of these registers.
Table 8-3. Reset Condition for Special Registers
Condition Program
Counter
STATUS
Register(2,3)
PCON0
Register
PCON1
Register
Power-on Reset 0 -110 0000 0011 110x ---- -1-1
Brown-out Reset 0 -110 0000 0011 11u0 ---- -u-u
MCLR Reset
during normal
operation
0-uuu uuuu uuuu 0uuu uuuu-u-u
MCLR Reset
during Sleep
0-10u uuuu uuuu 0uuu uuuu-u-u
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 96
...........continued
Condition Program
Counter
STATUS
Register(2,3)
PCON0
Register
PCON1
Register
WDT Time-out
Reset
0-0uu uuuu uuu0 uuuu uuuu-u-u
WDT Wake-up
from Sleep
PC + 2 -00u uuuu uuuu uuuu uuuu-u-u
WWDT Window
Violation Reset
0-uuu uuuu uu0u uuuu uuuu-u-u
Interrupt Wake-up
from Sleep
PC + 2(1) -10u 0uuu uuuu uuuu uuuu-u-u
RESET Instruction
Executed
0-uuu uuuu uuuu u0uu uuuu-u-u
Stack Overflow
Reset (STVREN =
1)
0-uuu uuuu 1uuu uuuu uuuu-u-u
Stack Underflow
Reset (STVREN =
1)
0-uuu uuuu u1uu uuuu uuuu-u-u
Data Protection
(Fuse Fault)
0---u uuuu uuuu uuuu ---- -u-0
VREG or ULP
Ready Fault
0---1 1000 0011 001u ---- -0-1
Legend: u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’.
Note: 
1. When the wake-up is due to an interrupt and Global Interrupt Enable bit (GIE) is set, the return
address is pushed on the stack and PC is loaded with the corresponding interrupt vector
(depending on source, high or low priority) after execution of PC + 2.
2. If a Status bit is not implemented, that bit will be read as ‘0’.
3. Status bits Z, C, DC are reset by POR/BOR.
Related Links
10.8.5 STATUS
8.12 Power Control (PCON0) Register
The Power Control (PCON0) register contains flag bits to differentiate between a:
Brown-out Reset (BOR)
Power-on Reset (POR)
Reset Instruction Reset (RI)
MCLR Reset (RMCLR)
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 97
Watchdog Timer Reset (RWDT)
Watchdog Window Violation (WDTWV)
Stack Underflow Reset (STKUNF)
Stack Overflow Reset (STKOVF)
The Power Control register bits are shown in 8.14.2 PCON0.
Hardware will change the corresponding register bit during the Reset process; if the Reset was not
caused by the condition, the bit remains unchanged (Table 8-3).
Software should reset the bit to the Inactive state after restart (hardware will not reset the bit).
Software may also set any PCON0 bit to the Active state, so that user code may be tested, but no Reset
action will be generated.
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 98
8.13 Register Summary - BOR Control and Power Control
Address Name Bit Pos.
0x0EDB BORCON 7:0 SBOREN BORRDY
0x0EDC
...
0x0FD5
Reserved
0x0FD6 PCON1 7:0 RVREG RCM
0x0FD7 PCON0 7:0 STKOVF STKUNF WDTWV RWDT RMCLR RI POR BOR
8.14 Register Definitions: Power Control
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 99
8.14.1 BORCON
Name:  BORCON
Address:  0xEDB
Brown-out Reset Control Register
Bit 7 6 5 4 3 2 1 0
SBOREN BORRDY
Access R/W R
Reset 1 q
Bit 7 – SBOREN Software Brown-out Reset Enable bit
Reset States: POR/BOR = 1
All Other Resets = u
Value Condition Description
If BOREN≠ 01 SBOREN is read/write, but has no effect on the BOR.
1If BOREN= 01 BOR Enabled
0If BOREN= 01 BOR Disabled
Bit 0 – BORRDY Brown-out Reset Circuit Ready Status bit
Reset States: POR/BOR = q
All Other Resets = u
Value Description
1The Brown-out Reset Circuit is active and armed
0The Brown-out Reset Circuit is disabled or is warming up
Related Links
3.7.2 CONFIG2
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 100
8.14.2 PCON0
Name:  PCON0
Address:  0xFD7
Power Control Register 0
Bit 7 6 5 4 3 2 1 0
STKOVF STKUNF WDTWV RWDT RMCLR RI POR BOR
Access R/W/HS R/W/HS R/W/HC R/W/HC R/W/HC R/W/HC R/W/HC R/W/HC
Reset 0 0 1 1 1 1 0 q
Bit 7 – STKOVF Stack Overflow Flag bit
Reset States: POR/BOR = 0
All Other Resets = q
Value Description
1A Stack Overflow occurred (more CALLs than fit on the stack)
0A Stack Overflow has not occurred or set to ‘0’ by firmware
Bit 6 – STKUNF Stack Underflow Flag bit
Reset States: POR/BOR = 0
All Other Resets = q
Value Description
1A Stack Underflow occurred (more RETURNs than CALLs)
0A Stack Underflow has not occurred or set to ‘0’ by firmware
Bit 5 – WDTWV Watchdog Window Violation Flag bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1A WDT window violation has not occurred or set to ‘1’ by firmware
0A CLRWDT instruction was issued when the WDT Reset window was closed (set to ‘0’ in
hardware when a WDT window violation Reset occurs)
Bit 4 – RWDT WDT Reset Flag bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1A WDT overflow/time-out Reset has not occurred or set to ‘1’ by firmware
0A WDT overflow/time-out Reset has occurred (set to ‘0’ in hardware when a WDT Reset
occurs)
Bit 3 – RMCLR  MCLR Reset Flag bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1A MCLR Reset has not occurred or set to ‘1’ by firmware
0A MCLR Reset has occurred (set to ‘0’ in hardware when a MCLR Reset occurs)
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 101
Bit 2 – RI  RESET Instruction Flag bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1A RESET instruction has not been executed or set to ‘1’ by firmware
0A RESET instruction has been executed (set to ‘0’ in hardware upon executing a RESET
instruction)
Bit 1 – POR Power-on Reset Status bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1No Power-on Reset occurred or set to ‘1’ by firmware
0A Power-on Reset occurred (set to ‘0’ in hardware when a Power-on Reset occurs)
Bit 0 – BOR Brown-out Reset Status bit
Reset States: POR/BOR = q
All Other Resets = u
Value Description
1No Brown-out Reset occurred or set to ‘1’ by firmware
0A Brown-out Reset occurred (set to ‘0’ in hardware when a Brown-out Reset occurs)
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 102
8.14.3 PCON1
Name:  PCON1
Address:  0xFD6
Power Control Register 1
Bit 7 6 5 4 3 2 1 0
RVREG RCM
Access R/W/HC R/W/HC
Reset 1 1
Bit 2 – RVREG Main LDO Voltage Regulator Reset Flag bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1No LDO or ULP “ready” Reset has occured; or set to ‘1’ by firmware
0LDO or ULP “ready” Reset has occurred (VDDCORE reached its minimum spec)
Bit 0 – RCM Configuration Memory Reset Flag bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1A Reset occurred due to corruption of the configuration and/or calibration data latches
0The configuration and calibration latches have not been corrupted
PIC18F26/45/46Q10
Resets
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 103
9. (WWDT) Windowed Watchdog Timer
The Watchdog Timer (WDT) is a system timer that generates a Reset if the firmware does not issue a
CLRWDT instruction within the time-out period. The Watchdog Timer is typically used to recover the
system from unexpected events. The Windowed Watchdog Timer (WWDT) differs in that CLRWDT
instructions are only accepted when they are performed within a specific window during the time-out
period.
The WWDT has the following features:
Selectable clock source
Multiple operating modes
WWDT is always on
WWDT is off when in Sleep
WWDT is controlled by software
WWDT is always off
Configurable time-out period is from 1 ms to 256s (nominal)
Configurable window size from 12.5% to 100% of the time-out period
Multiple Reset conditions
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 104
Figure 9-1. Windowed Watchdog Timer Block Diagram
Filename: 10-000162A.vsd
Title: Windowed Watchdog Timer Timer Block Diagram
Last Edit: 1/2/2014
First Used: PIC16(L)F1613 (LECQ)
Notes:
Rev. 10-000 162A
1/2/201 4
WINDOW
CLRWDT
RESET
WDT Time-out
WDT
Window
Violation
PS
5-bit
WDT Counter
Overflow
Latch
18-bit Prescale
Counter
000
011
010
001
100
101
110
111Reserved
Reserved
Reserved
Reserved
Reserved
SOSC
MFINTOSC/16
LFINTOSC
R
R
CS
WWDT
Armed
Window
Sizes Comparator
Window Closed
E
WDTE<1:0> = 01
WDTE<1:0> = 11
WDTE<1:0> = 10
SEN
Sleep
9.1 Independent Clock Source
The WWDT can derive its time base from either the 31 kHz LFINTOSC or 31.25 kHz MFINTOSC internal
oscillators, depending on the value of WDTE Configuration bits.
If WDTE = 'b1x, then the clock source will be enabled depending on the WDTCCS Configuration bits.
If WDTE = 'b01, the SEN bit should be set by software to enable WWDT, and the clock source is
enabled by the WDTCS bits.
Time intervals in this chapter are based on a minimum nominal interval of 1 ms. See “Electrical
Specifications” for LFINTOSC and MFINTOSC tolerances.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 105
Related Links
3.7.3 CONFIG3
39.4.2 Internal Oscillator Parameters(1)
9.2 WWDT Operating Modes
The Windowed Watchdog Timer module has four operating modes controlled by the WDTE bits in
Configuration Words. See Table 9-1.
9.2.1 WWDT Is Always On
When the WDTE bits of Configuration Words are set to ‘11’, the WWDT is always on.
WWDT protection is active during Sleep.
9.2.2 WWDT Is Off in Sleep
When the WDTE bits of Configuration Words are set to ‘10’, the WWDT is on, except in Sleep.
WWDT protection is not active during Sleep.
9.2.3 WWDT Controlled by Software
When the WDTE bits of Configuration Words are set to ‘01’, the WWDT is controlled by the SEN bit.
WWDT protection is unchanged by Sleep. See the following table for more details.
Table 9-1. WWDT Operating Modes
WDTE<1:0> SEN Device Mode WWDT Mode
11 X X Active
10 X
Awake Active
Sleep Disabled
01
1X Active
0X Disabled
00 X X Disabled
9.3 Time-out Period
If the WDTCPS Configuration bits default to 0’b11111, then the WDTPS bits set the time-out period
from 1 ms to 256 seconds (nominal). If any value other than the default value is assigned to WDTCPS
Configuration bits, then the timer period will be based on the WDTCPS bits in the CONFIG3 register. After
a Reset, the default time-out period is 2s.
Related Links
3.7.3 CONFIG3
9.4 Watchdog Window
The Windowed Watchdog Timer has an optional Windowed mode that is controlled by the WDTCWS
Configuration bits and WINDOW bits. In the Windowed mode, the CLRWDT instruction must occur within
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 106
the allowed window of the WDT period. Any CLRWDT instruction that occurs outside of this window will
trigger a window violation and will cause a WWDT Reset, similar to a WWDT time-out. See Figure 9-2 for
an example.
The window size is controlled by the WINDOW Configuration bits, or the WINDOW bits, if WDTCWS =
111.
The five Most Significant bits of the WDTTMR register are used to determine whether the window is open,
as defined by the WINDOW bits.
In the event of a window violation, a Reset will be generated and the WDTWV bit of the PCON0 register
will be cleared. This bit is set by a POR or can be set in firmware.
Related Links
8.14.2 PCON0
9.5 Clearing the WWDT
The WWDT is cleared when any of the following conditions occur:
Any Reset
Valid CLRWDT instruction is executed
Device enters Sleep
Exit Sleep by Interrupt
WWDT is disabled
Oscillator Start-up Timer (OST) is running
Any write to the WDTCON0 or 9.8.2 WDTCON1 registers
9.5.1 CLRWDT Considerations (Windowed Mode)
When in Windowed mode, the WWDT must be armed before a CLRWDT instruction will clear the timer.
This is performed by reading the WDTCON0 register. Executing a CLRWDT instruction without performing
such an arming action will trigger a window violation regardless of whether the window is open or not.
See Table 9-2 for more information.
9.6 Operation During Sleep
When the device enters Sleep, the WWDT is cleared. If the WWDT is enabled during Sleep, the WWDT
resumes counting. When the device exits Sleep, the WWDT is cleared again.
The WWDT remains clear until the Oscillator Start-up Timer (OST) completes, if enabled.
When a WWDT time-out occurs while the device is in Sleep, no Reset is generated. Instead, the device
wakes up and resumes operation. The TO and PD bits in the STATUS register are changed to indicate
the event. The RWDT bit in the PCON0 register can also be used.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 107
Table 9-2. WWDT Clearing Conditions
Conditions WWDT
WDTE = 00
Cleared
WDTE = 01 and SEN = 0
WDTE = 10 and enter Sleep
CLRWDT Command
Oscillator Fail Detected
Exit Sleep + System Clock = SOSC, EXTRC, INTOSC, EXTCLK
Exit Sleep + System Clock = XT, HS, LP Cleared until the end of OST
Change INTOSC divider (IRCF bits) Unaffected
Figure 9-2. Window Period and Delay
Filename: 10-000163A.vsd
Title: WDT WINDOW PERIOD AND DELAY
Last Edit: 8/15/2016
First Used: PIC16(L)F1613 (LECQ)
Notes:
Rev. 10-000163A
8/15/2016
Window Period
CLRWDT Instruction
(or other WDT Reset)
Window Delay
(window violation can occur)
Window Closed Window Open
Time-out Event
Related Links
4.2.1.3 Oscillator Start-up Timer (OST)
10.8.5 STATUS
8.14.2 PCON0
10. Memory Organization
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 108
9.7 Register Summary - WDT Control
Address Name Bit Pos.
0x0ECD WDTCON0 7:0 WDTPS[4:0] SEN
0x0ECE WDTCON1 7:0 WDTCS[2:0] WINDOW[2:0]
0x0ECF WDTPSL 7:0 PSCNTL[7:0]
0x0ED0 WDTPSH 7:0 PSCNTH[7:0]
0x0ED1 WDTTMR 7:0 WDTTMR[4:0] STATE PSCNT[1:0]
9.8 Register Definitions: Windowed Watchdog Timer Control
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 109
9.8.1 WDTCON0
Name:  WDTCON0
Address:  0xECD
Watchdog Timer Control Register 0
Bit 7 6 5 4 3 2 1 0
WDTPS[4:0] SEN
Access R/W R/W R/W R/W R/W R/W
Reset q q q q q 0
Bits 5:1 – WDTPS[4:0]  Watchdog Timer Prescale Select bits(1)
Bit Value = Prescale Rate
Value Description
11111
to
10011
Reserved. Results in minimum interval (1 ms)
10010 1:8388608 (223) (Interval 256s nominal)
10001 1:4194304 (222) (Interval 128s nominal)
10000 1:2097152 (221) (Interval 64s nominal)
01111 1:1048576 (220) (Interval 32s nominal)
01110 1:524288 (219) (Interval 16s nominal)
01101 1:262144 (218) (Interval 8s nominal)
01100 1:131072 (217) (Interval 4s nominal)
01011 1:65536 (Interval 2s nominal) (Reset value)
01010 1:32768 (Interval 1s nominal)
01001 1:16384 (Interval 512 ms nominal)
01000 1:8192 (Interval 256 ms nominal)
00111 1:4096 (Interval 128 ms nominal)
00110 1:2048 (Interval 64 ms nominal)
00101 1:1024 (Interval 32 ms nominal)
00100 1:512 (Interval 16 ms nominal)
00011 1:256 (Interval 8 ms nominal)
00010 1:128 (Interval 4 ms nominal)
00001 1:64 (Interval 2 ms nominal)
00000 1:32 (Interval 1 ms nominal)
Bit 0 – SEN Software Enable/Disable for Watchdog Timer bit
Value Condition Description
If WDTE = 1x This bit is ignored
1If WDTE = 01 WDT is turned on
0If WDTE = 01 WDT is turned off
If WDTE = 00 This bit is ignored
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 110
Note: 
1. Times are approximate. WDT time is based on 31 kHz LFINTOSC.
2. When WDTCPS in CONFIG3 = 11111, the Reset value (q) of WDTPS is ‘01011’. Otherwise, the
Reset value of WDTPS is equal to WDTCPS in CONFIG3.
3. When WDTCPS in CONFIG3L ≠ 11111, these bits are read-only.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 111
9.8.2 WDTCON1
Name:  WDTCON1
Address:  0xECE
Watchdog Timer Control Register 1
Bit 7 6 5 4 3 2 1 0
WDTCS[2:0] WINDOW[2:0]
Access R/W R/W R/W R/W R/W R/W
Reset q q q q q q
Bits 6:4 – WDTCS[2:0] Watchdog Timer Clock Select bits
Value Description
111 to
010
Reserved
001 MFINTOSC 31.25 kHz
000 LFINTOSC 31 kHz
Bits 2:0 – WINDOW[2:0] Watchdog Timer Window Select bits
WINDOW Window delay Percent of time Window opening Percent of time
111 N/A 100
110 12.5 87.5
101 25 75
100 37.5 62.5
011 50 50
010 62.5 37.5
001 75 25
000 87.5 12.5
Note: 
1. If WDTCCS in CONFIG3 = 111, the Reset value of WDTCS is ‘000’.
2. The Reset value (q) of WINDOW is determined by the value of WDTCWS in the CONFIG3 register.
3. If WDTCCS in CONFIG3 ≠ 111, these bits are read-only.
4. If WDTCWS in CONFIG3 ≠ 111, these bits are read-only.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 112
9.8.3 WDTPSH
Name:  WDTPSH
Address:  0xED0
WWDT Prescale Select High Register (Read-Only)
Bit 7 6 5 4 3 2 1 0
PSCNTH[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – PSCNTH[7:0]  Prescale Select High Byte bits(1)
Note: 
1. The 18-bit WDT prescale value, PSCNT<17:0> includes the WDTPSL, WDTPSH and the lower bits
of the WDTTMR registers. PSCNT<17:0> is intended for debug operations and should be read
during normal operation.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 113
9.8.4 WDTPSL
Name:  WDTPSL
Address:  0xECF
WWDT Prescale Select Low Register (Read-Only)
Bit 7 6 5 4 3 2 1 0
PSCNTL[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – PSCNTL[7:0]  Prescale Select Low Byte bits(1)
Note: 
1. The 18-bit WDT prescale value, PSCNT<17:0> includes the WDTPSL, WDTPSH and the lower bits
of the WDTTMR registers. PSCNT<17:0> is intended for debug operations and should be read
during normal operation.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 114
9.8.5 WDTTMR
Name:  WDTTMR
Address:  0xED1
WDT Timer Register (Read-Only)
Bit 7 6 5 4 3 2 1 0
WDTTMR[4:0] STATE PSCNT[1:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 7:3 – WDTTMR[4:0] Watchdog Window Value bits
WINDOW WDT Window State Open Percent
Closed Open
111 N/A 00000-11111 100
110 00000-00011 00100-11111 87.5
101 00000-00111 01000-11111 75
100 00000-01011 01100-11111 62.5
011 00000-01111 10000-11111 50
010 00000-10011 10100-11111 37.5
001 00000-10111 11000-11111 25
000 00000-11011 11100-11111 12.5
Bit 2 – STATE WDT Armed Status bit
Value Description
1WDT is armed
0WDT is not armed
Bits 1:0 – PSCNT[1:0]  Prescale Select Upper Byte bits(1)
Note: 
1. The 18-bit WDT prescale value, PSCNT<17:0> includes the WDTPSL, WDTPSH and the lower bits
of the WDTTMR registers. PSCNT<17:0> is intended for debug operations and should be read
during normal operation.
PIC18F26/45/46Q10
(WWDT) Windowed Watchdog Timer
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 115
10. Memory Organization
There are three types of memory in PIC18 enhanced microcontroller devices:
Program Memory
Data RAM
Data EEPROM
In Harvard architecture devices, the data and program memories use separate buses that allows for
concurrent access of the two memory spaces. The data EEPROM, for practical purposes, can be
regarded as a peripheral device, since it is addressed and accessed through a set of control registers.
Additional detailed information on the operation of the Program Flash Memory and data EEPROM
memory is provided in the Nonvolatile Memory (NVM) control section.
10.1 Program Memory Organization
PIC18 microcontrollers implement a 21-bit Program Counter, which is capable of addressing a 2 Mbyte
program memory space. Accessing a location between the upper boundary of the physically implemented
memory and the 2 Mbyte address will return all ‘0’s (a NOP instruction).
Refer to the following tables for device memory maps and code protection Configuration bits associated
with the various sections of PFM.
PIC18 devices have two interrupt vectors. The Reset vector address is at 0000h and the interrupt vector
addresses are at 0008h and 0018h.
PIC18F26/45/46Q10
Memory Organization
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 116
Figure 10-1. Program and Data Memory Map
Rev. 40-000101C
6/16/2017
PIC18F45Q10
PIC18F26Q10
PIC18F46Q10
Note 1
00 0000h
00 0008h
00 0018h
00 001Ah
00 7FFFh
00 8000h
00 FFFFh
01 0000h
01 FFFFh
02 0000h
1F FFFFh
20 0000h
20 00FFh
20 0100h
2F FFFFh
30 0000h
30 000Bh
30 000Ch
30 02FFh
30 0300h
30 FFFBh
31 0000h
31 00FFh
Data EEPROM
(256 Bytes)
31 0100h
31 03FFh
31 0400h
3F FFFBh
Unimplemented
3F FFFCh
3F FFFDh
3F FFFEh
3F FFFFh
Note 1: The stack is a separate SRAM panel, apart from all user memory panels.
2: The addresses do not roll over. The region is read as ‘0’.
3: Not code-protected.
4: Device/Revision IDs are hard-coded in silicon.
Interrupt Vector Low
User IDs (256 Words)(3)
Reserved
Configuration Words (6 Words)(3)
Not
Present(2)
Program Flash
Memory
(16 KW)
Not
Present(2)
Program Flash
Memory
(32 KW)
Address
Device
Stack (31 Levels)
Reset Vector
Interrupt Vector High
Reserved
Unimplemented
Revision ID (1 Word)(4)
Device ID (1 Word)(4)
Data EEPROM
(1 k Bytes)
Unimplemented
PIC18F26/45/46Q10
Memory Organization
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 117
Figure 10-2. Memory Map and Code Protection Control
Rev. 40-000100C
12/19/2017
PIC18F45Q10 PIC18F26Q10
PIC18F46Q10
00 0000h
to
00 07FFh
Boot Block
1 KW
CP, WRTB, EBTRB
Boot Block
1 KW
CP, WRTB, EBTRB
00 0800h
to
00 1FFFh
Block 0
3 KW
CP, WRT0, EBTR0
00 2000h
to
00 3FFFh
Block 1
4 KW
CP, WRT1, EBTR1
00 4000h
to
00 5FFFh
Block 2
4 KW
CP, WRT2, EBTR2
00 6000h
to
00 7FFFh
Block 3
4 KW
CP, WRT3, EBTR3
00 8000h
to
00 BFFFh
Block 2
8 KW
CP, WRT2, EBTR2
00 C000h
to
00 FFFFh
Block 3
8 KW
CP, WRT3, EBTR3
01 0000h
to
01 3FFFh
01 4000h
to
01 7FFFh
01 8000h
to
01 BFFFh
01 C000h
to
01 FFFFh
CONFIG 30 0000h
to
30 000Bh
31 0000h
to
31 00FFh
256 Words
CPD, WRTD
31 0100h
to
31 01FFh
Region Address
Device
PFM
Block 0
7 KW
CP, WRT0, EBTR0
Block 1
8 KW
CP, WRT1, EBTR1
Configuration Words
WRTC
Data
EEPROM
Not
Present
Not
Present
1 KW
CPD, WRTD
PIC18F26/45/46Q10
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10.1.1 Program Counter
The Program Counter (PC) specifies the address of the instruction to fetch for execution. The PC is 21
bits wide and is contained in three separate 8-bit registers. The low byte, known as the PCL register, is
both readable and writable. The high byte, or PCH register, contains the PC<15:8> bits; it is not directly
readable or writable. Updates to the PCH register are performed through the PCLATH register. The upper
byte is called PCU. This register contains the PC<20:16> bits; it is also not directly readable or writable.
Updates to the PCU register are performed through the PCLATU register.
The contents of PCLATH and PCLATU are transferred to the Program Counter by any operation that
writes PCL. Similarly, the upper two bytes of the Program Counter are transferred to PCLATH and
PCLATU by an operation that reads PCL. This is useful for computed offsets to the PC (see 10.1.3.1
Computed GOTO).
The PC addresses bytes in the program memory. To prevent the PC from becoming misaligned with word
instructions, the Least Significant bit of PCL is fixed to a value of ‘0’. The PC increments by two to
address sequential instructions in the program memory.
The CALL, RCALL, GOTO and program branch instructions write to the Program Counter directly. For
these instructions, the contents of PCLATH and PCLATU are not transferred to the Program Counter.
10.1.2 Return Address Stack
The return address stack allows any combination of up to 31 program calls and interrupts to occur. The
PC is pushed onto the stack when a CALL or RCALL instruction is executed or an interrupt is
Acknowledged. The PC value is pulled off the stack on a RETURN, RETLW or a RETFIE instruction.
PCLATU and PCLATH are not affected by any of the RETURN or CALL instructions.
The stack operates as a 31-word by 21-bit RAM and a 5-bit Stack Pointer, or as a 35-word by 21-bit RAM
with a 6-bit Stack Pointer in ICD mode. The stack space is not part of either program or data space. The
Stack Pointer is readable and writable and the address on the top of the stack is readable and writable
through the Top-of-Stack (TOS) Special File registers. Data can also be pushed to, or popped from the
stack, using these registers.
A CALL type instruction causes a push onto the stack; the Stack Pointer is first incremented and the
location pointed to by the Stack Pointer is written with the contents of the PC (already pointing to the
instruction following the CALL). A RETURN type instruction causes a pop from the stack; the contents of
the location pointed to by the STKPTR are transferred to the PC and then the Stack Pointer is
decremented.
The Stack Pointer is initialized to ‘0b00000’ after all Resets. There is no RAM associated with the location
corresponding to a Stack Pointer value of ‘0b00000’; this is only a Reset value. Status bits in the PCON0
register indicate if the stack is full or has overflowed or has under-flowed.
10.1.2.1 Top-of-Stack Access
Only the top of the return address stack (TOS) is readable and writable. A set of three registers,
TOSU:TOSH:TOSL, hold the contents of the stack location pointed to by the STKPTR register (see
Figure 10-3). This allows users to implement a software stack if necessary. After a CALL, RCALL or
interrupt, the software can read the pushed value by reading the TOSU:TOSH:TOSL registers. These
values can be placed on a user defined software stack. At return time, the software can return these
values to TOSU:TOSH:TOSL and do a return.
The user must disable the Global Interrupt Enable (GIE) bits while accessing the stack to prevent
inadvertent stack corruption.
PIC18F26/45/46Q10
Memory Organization
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Figure 10-3. Return Address Stack and Associated Registers
00011
001A34h
11111
11110
11101
00010
00001
00000
00010
Return Address Stack <20:0>
Top-of-Stack
000D58h
TOSLTOSHTOSU
34h1Ah00h
STKPTR<4:0>
Top-of-Stack Registers Stack Pointer
Rev. 30-00094A
4/12/2017
10.1.2.2 Return Stack Pointer
The 10.8.4 STKPTR register contains the Stack Pointer value. The STKOVF (Stack Overflow) Status bit
and the STKUNF (Stack Underflow) Status bit can be accessed using the PCON0 register. The value of
the Stack Pointer can be 0 through 31. On Reset, the Stack Pointer value will be zero. The user may read
and write the Stack Pointer value. This feature can be used by a Real-Time Operating System (RTOS) for
stack maintenance. After the PC is pushed onto the stack 32 times (without popping any values off the
stack), the STKOVF bit is set. The STKOVF bit is cleared by software or by a POR. The action that takes
place when the stack becomes full depends on the state of the STVREN (Stack Overflow Reset Enable)
Configuration bit.
If STVREN is set (default), a Reset will be generated and a Stack Overflow will be indicated by the
STKOVF bit when the 32nd push is initiated. This includes CALL and CALLW instructions, as well as
stacking the return address during an interrupt response. The STKOVF bit will remain set and the Stack
Pointer will be set to zero.
If STVREN is cleared, the STKOVF bit will be set on the 32nd push and the Stack Pointer will remain at
31 but no Reset will occur. Any additional pushes will overwrite the 31st push but the STKPTR will remain
at 31.
Setting STKOVF = 1 in software will change the bit, but will not generate a Reset.
The STKUNF bit is set when a stack pop returns a value of zero. The STKUNF bit is cleared by software
or by POR. The action that takes place when the stack becomes full depends on the state of the
STVREN (Stack Overflow Reset Enable) Configuration bit.
If STVREN is set (default) and the stack has been popped enough times to unload the stack, the next pop
will return a value of zero to the PC, it will set the STKUNF bit and a Reset will be generated. This
condition can be generated by the RETURN, RETLW and RETFIE instructions.
If STVREN is cleared, the STKUNF bit will be set, but no Reset will occur.
Important:  Returning a value of zero to the PC on an underflow has the effect of vectoring the
program to the Reset vector, where the stack conditions can be verified and appropriate actions
can be taken. This is not the same as a Reset, as the contents of the SFRs are not affected.
Related Links
3.7.2 CONFIG2
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10.1.2.3 Stack Overflow and Underflow Resets
Device Resets on Stack Overflow and Stack Underflow conditions are enabled by setting the STVREN
Configuration bit in Configuration. When STVREN is set, a Full or Underflow condition will set the
respective STKOVF or STKUNF bit and then cause a device Reset. When STVREN is cleared, a Full or
Underflow condition will set the respective STKOVF or STKUNF bit but not cause a device Reset. The
STKOVF or STKUNF bits are cleared by the user software or a Power-on Reset.
10.1.2.4 PUSH and POP Instructions
Since the Top-of-Stack is readable and writable, the ability to push values onto the stack and pull values
off the stack without disturbing normal program execution is a desirable feature. The PIC18 instruction set
includes two instructions, PUSH and POP, that permit the TOS to be manipulated under software control.
TOSU, TOSH and TOSL can be modified to place data or a return address on the stack.
The PUSH instruction places the current PC value onto the stack. This increments the Stack Pointer and
loads the current PC value onto the stack.
The POP instruction discards the current TOS by decrementing the Stack Pointer. The previous value
pushed onto the stack then becomes the TOS value.
10.1.2.5 Fast Register Stack
A Fast Register Stack is provided for the STATUS, WREG and BSR registers, to provide a “fast return”
option for interrupts. The Stack for each register is only one level deep and is neither readable nor
writable. It is loaded with the current value of the corresponding register when the processor vectors for
an interrupt. All interrupt sources will push values into the Fast Register Stack. The values in the registers
are then loaded back into their associated registers if the RETFIE, FAST instruction is used to return
from the interrupt.
Important:  The TO and PD bits of the STATUS register are not copied over in this operation.
If both low and high-priority interrupts are enabled, the Stack registers cannot be used reliably to return
from low-priority interrupts. If a high-priority interrupt occurs while servicing a low-priority interrupt, the
Stack register values stored by the low-priority interrupt will be overwritten. In these cases, users must
save the key registers by software during a low-priority interrupt.
If interrupt priority is not used, all interrupts may use the Fast Register Stack for returns from interrupt. If
no interrupts are used, the Fast Register Stack can be used to restore the STATUS, WREG and BSR
registers at the end of a subroutine call. To use the Fast Register Stack for a subroutine call, a CALL
label, FAST instruction must be executed to save the STATUS, WREG and BSR registers to the Fast
Register Stack. A RETURN, FAST instruction is then executed to restore these registers from the Fast
Register Stack.
The following example shows a source code example that uses the Fast Register Stack during a
subroutine call and return.
Example 10-1. Fast Register Stack Code Example
CALL SUB1, FAST ;STATUS, WREG, BSR SAVED IN FAST REGISTER STACK
SUB1:
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RETURN, FAST ;RESTORE VALUES SAVED IN FAST REGISTER STACK
10.1.3 Look-up Tables in Program Memory
There may be programming situations that require the creation of data structures, or look-up tables, in
program memory. For PIC18 devices, look-up tables can be implemented in two ways:
Computed GOTO
Table Reads
10.1.3.1 Computed GOTO
A computed GOTO is accomplished by adding an offset to the Program Counter. An example is shown in
the following code example.
A look-up table can be formed with an ADDWF PCL instruction and a group of RETLW nn instructions. The
W register is loaded with an offset into the table before executing a call to that table. The first instruction
of the called routine is the ADDWF PCL instruction. The next instruction executed will be one of the RETLW
nn instructions that returns the value ‘nn’ to the calling function.
The offset value (in WREG) specifies the number of bytes that the Program Counter should advance and
must be multiples of two (LSb = 0).
In this method, only one data byte may be stored in each instruction location and room on the return
address stack is required.
Example 10-2. Computed GOTO Using an Offset Value
RLNCF OFFSET, W ; W must be an even number, Max OFFSET = 127
CALL TABLE
ORG nn00h ; 00 in LSByte ensures no addition overflow
TABLE:
ADDWF PCL ; Add OFFSET to program counter
RETLW A ; Value @ OFFSET=0
RETLW B ; Value @ OFFSET=1
RETLW C ; Value @ OFFSET=2
.
.
.
10.1.3.2 Table Reads and Table Writes
A more compact method of storing data in program memory allows two bytes of data to be stored in each
instruction location.
Look-up table data may be stored two bytes per program word by using table reads and writes. The Table
Pointer (TBLPTR) register specifies the byte address and the Table Latch (TABLAT) register contains the
data that is read from or written to program memory. Data is transferred to or from program memory one
byte at a time.
Table read and table write operations are discussed further in the Table Reads and Table Writes section.
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10.2 PIC18 Instruction Cycle
10.2.1 Clocking Scheme
The microcontroller clock input, whether from an internal or external source, is internally divided by four to
generate four non-overlapping quadrature clocks (Q1, Q2, Q3 and Q4). Internally, the Program Counter is
incremented on every Q1; the instruction is fetched from the program memory and latched into the
instruction register during Q4. The instruction is decoded and executed during the following Q1 through
Q4. The clocks and instruction execution flow are shown in the following figure.
Figure 10-4. CLOCK/INSTRUCTION CYCLE
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Q1
Q2
Q3
Q4
PC
OSC2/CLKOUT
(RC mode)
PC PC + 2 PC + 4
Fetch INST (PC)
Execute INST (PC – 2)
Fetch INST (PC + 2)
Execute INST (PC)
Fetch INST (PC + 4)
Execute INST (PC + 2)
Internal
Phase
Clock
Rev. 30-000095A
4/13/2017
10.2.2 Instruction Flow/Pipelining
An “Instruction Cycle” consists of four Q cycles: Q1 through Q4. The instruction fetch and execute are
pipelined in such a manner that a fetch takes one instruction cycle, while the decode and execute take
another instruction cycle. However, due to the pipelining, each instruction effectively executes in one
cycle. If an instruction causes the Program Counter to change (e.g., GOTO), then two cycles are required
to complete the instruction as shown in the figure below.
A fetch cycle begins with the Program Counter (PC) incrementing in Q1.
In the execution cycle, the fetched instruction is latched into the Instruction Register (IR) in cycle Q1. This
instruction is then decoded and executed during the Q2, Q3 and Q4 cycles. Data memory is read during
Q2 (operand read) and written during Q4 (destination write).
Figure 10-5. Instruction Pipeline Flow
Rev. 10-000337A
9/27/2017
TCY0 TCY1TCY2 TCY3 TCY4 TCY5
1. MOVLW 55h
2. MOVWF PORTB
3. BRA Sub_1
4. BSF PORTA, BITS (Forced NOP)
5. Instruction @ address Sub_1
Fetch 1 Execute 1
Fetch 2 Execute 2
Fetch 3 Execute 3
Fetch 4 Flush (NOP)
Fetch Sub_1 Execute Sub_1
All instructions are single cycle except for any program branches. These take two cycles since the fetch instruction
is “flushed” from the pipeline while the new instruction is being fetched and then executed.
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10.2.3 Instructions in Program Memory
The program memory is addressed in bytes. Instructions are stored as either two bytes or four bytes in
program memory. The Least Significant Byte of an instruction word is always stored in a program memory
location with an even address (LSb = 0). To maintain alignment with instruction boundaries, the PC
increments in steps of two and the LSb will always read ‘0’ (see 10.1.1 Program Counter).
The Instructions in Program Memory figure below shows how instruction words are stored in the program
memory.
The CALL and GOTO instructions have the absolute program memory address embedded into the
instruction. Since instructions are always stored on word boundaries, the data contained in the instruction
is a word address. The word address is written to PC<20:1>, which accesses the desired byte address in
program memory. Instruction #2 in the example shows how the instruction GOTO 0006h is encoded in the
program memory. Program branch instructions, which encode a relative address offset, operate in the
same manner. The offset value stored in a branch instruction represents the number of single-word
instructions that the PC will be offset by. The Instruction Set Summary provides further details of the
instruction set.
Figure 10-6. Instructions in Program Memory
Word Address
LSB = 1LSB = 0
Program Memory
Byte Locations
000000h
000002h
000004h
000006h
Instruction 1: MOVLW 055h 0Fh 55h 000008h
Instruction 2: GOTO 0006h EFh 03h 00000Ah
F0h 00h 00000Ch
Instruction 3: MOVFF 123h, 456h C1h 23h 00000Eh
F4h 56h 000010h
000012h
000014h
Rev. 30-000112A4/19/2017
Related Links
37. Instruction Set Summary
10.2.4 Two-Word Instructions
The standard PIC18 instruction set has four two-word instructions: CALL, MOVFF, GOTO and LFSR. In all
cases, the second word of the instruction always has ‘1111’ as its four Most Significant bits; the other 12
bits are literal data, usually a data memory address.
The use of ‘1111’ in the 4 MSbs of an instruction specifies a special form of NOP. If the instruction is
executed in proper sequence – immediately after the first word – the data in the second word is accessed
and used by the instruction sequence. If the first word is skipped for some reason and the second word is
executed by itself, a NOP is executed instead. This is necessary for cases when the two-word instruction
is preceded by a conditional instruction that changes the PC. The Two-Word Instructions figure below
shows how this works.
Important:  See the 10.6 PIC18 Instruction Execution and the Extended Instruction Set
section for information on two-word instructions in the extended instruction set.
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Figure 10-7. Two-Word Instructions
CASE 1:
Object Code Source Code
0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?
1100 0001 0010 0011 MOVFF REG1, REG2 ; No, skip this word
1111 0100 0101 0110 ; Execute this word as a NOP
0010 0100 0000 0000 ADDWF REG3 ; continue code
CASE 2:
Object Code Source Code
0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?
1100 0001 0010 0011 MOVFF REG1, REG2 ; Yes, execute this word
1111 0100 0101 0110 ; 2nd word of instruction
0010 0100 0000 0000 ADDWF REG3 ; continue code
Rev. 30-000113A
4/19/2017
10.3 Data Memory Organization
Important:  The operation of some aspects of data memory are changed when the PIC18
extended instruction set is enabled. See 10.6 PIC18 Instruction Execution and the Extended
Instruction Set for more information.
The data memory in PIC18 devices is implemented as static RAM. Each register in the data memory has
a 12-bit address, allowing up to 4096 bytes of data memory. The memory space is divided into as many
as 16 banks that contain 256 bytes each. The figure below shows the data memory organization for all
devices in the device family.
The data memory contains Special Function Registers (SFRs) and General Purpose Registers (GPRs).
The SFRs are used for control and status of the controller and peripheral functions, while GPRs are used
for data storage and scratchpad operations in the user’s application. Any read of an unimplemented
location will read as ‘0’s.
The instruction set and architecture allow operations across all banks. The entire data memory may be
accessed by Direct, Indirect or Indexed Addressing modes. Addressing modes are discussed later in this
subsection.
To ensure that commonly used registers (SFRs and select GPRs) can be accessed in a single cycle,
PIC18 devices implement an Access Bank. This is a 256-byte memory space that provides fast access to
SFRs and the lower portion of GPR Bank 0 without using the Bank Select Register (BSR). The 10.3.2
Access Bank section provides a detailed description of the Access RAM.
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Figure 10-8. Data Memory Map
Rev. 40-000102C
6/16/2017
45Q10 26Q10 46Q10
00h-5Fh
60h-FFh
1 1h 00h-FFh
2 2h 00h-FFh
3 3h 00h-FFh
4 4h 00h-FFh
5 5h 00h-FFh
6 6h 00h-FFh
7 7h 00h-FFh Virtual Access Bank
8 8h 00h-FFh
9 9h 00h-FFh 00h-5Fh
10 Ah 00h-FFh 60h-FFh
11 Bh 00h-FFh
12 Ch 00h-FFh
13 Dh 00h-FFh
00h-1Eh
1Fh-9Ah
9Bh-FFh
00h-5Fh
60h-FFh
PIC18F
Sector RAM
14 Eh
Unimplemented
GPR
SFR
Fh15
addr<7:0>
0h0
BanK BSR<3:0>
addr<11:8>
10.3.1 Bank Select Register
Large areas of data memory require an efficient addressing scheme to make rapid access to any address
possible. Ideally, this means that an entire address does not need to be provided for each read or write
operation. For PIC18 devices, this is accomplished with a RAM banking scheme. This divides the
memory space into 16 contiguous banks of 256 bytes. Depending on the instruction, each location can be
addressed directly by its full 12-bit address, or an 8-bit low-order address and a 4-bit Bank Pointer.
Most instructions in the PIC18 instruction set make use of the Bank Pointer, known as the Bank Select
Register (10.8.13 BSR). This SFR holds the four Most Significant bits of a location’s address; the
instruction itself includes the eight Least Significant bits. Only the four lower bits of the BSR are
implemented (BSR<3:0>). The upper four bits are unused; they will always read ‘0’ and cannot be written
to. The BSR can be loaded directly by using the MOVLB instruction.
The value of the BSR indicates the bank in data memory; the eight bits in the instruction show the
location in the bank and can be thought of as an offset from the bank’s lower boundary. The relationship
between the BSR’s value and the bank division in data memory is shown in the figure below.
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Since up to 16 registers may share the same low-order address, the user must always be careful to
ensure that the proper bank is selected before performing a data read or write. For example, writing what
should be program data to an 8-bit address of F9h while the BSR is 0Fh will end up resetting the Program
Counter.
While any bank can be selected, only those banks that are actually implemented can be read or written
to. Writes to unimplemented banks are ignored, while reads from unimplemented banks will return ‘0’s.
Even so, the STATUS register will still be affected as if the operation was successful. The data memory
maps in the following figure indicate which banks are implemented.
In the core PIC18 instruction set, only the MOVFF instruction fully specifies the 12-bit address of the
source and target registers. This instruction ignores the BSR completely when it executes. All other
instructions include only the low-order address as an operand and must use either the BSR or the Access
Bank to locate their target registers.
Figure 10-9. Use of the Bank Select Register (Direct Addressing)
Note 1: The Access RAM bit of the instruction can be used to force an override of the selected bank (BSR<3:0>) to
the registers of the Access Bank.
2: The MOVFF instruction embeds the entire 12-bit address in the instruction.
Data Memory
Bank Select(2)
7 0
From Opcode(2)
0 0 0 0
Bank 3
through
Bank 13
0 0 1 0 1 1 1 1 1 1 1 1
7 0
BSR(1)
000h
100h
200h
300h
F00h
E00h
FFFh
Bank 0
Bank 1
Bank 2
Bank 14
Bank 15
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
Rev. 30-000108A
09/07/2017
10.3.2 Access Bank
While the use of the BSR with an embedded 8-bit address allows users to address the entire range of
data memory, it also means that the user must always ensure that the correct bank is selected.
Otherwise, data may be read from or written to the wrong location. This can be disastrous if a GPR is the
intended target of an operation, but an SFR is written to instead. Verifying and/or changing the BSR for
each read or write to data memory can become very inefficient.
To streamline access for the most commonly used data memory locations, the data memory is configured
with an Access Bank, which allows users to access a mapped block of memory without specifying a BSR.
The Access Bank consists of the first 96 bytes of memory (00h-5Fh) in Bank 0 and the last 160 bytes of
memory (60h-FFh) in Block 15. The lower half is known as the “Access RAM” and is composed of GPRs.
This upper half is also where the device’s SFRs are mapped. These two areas are mapped contiguously
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in the Access Bank and can be addressed in a linear fashion by an 8-bit address (see Data Memory
Map).
The Access Bank is used by core PIC18 instructions that include the Access RAM bit (the ‘a’ parameter
in the instruction). When ‘a’ is equal to ‘1’, the instruction uses the BSR and the 8-bit address included in
the opcode for the data memory address. When ‘a’ is ‘0’, however, the instruction is forced to use the
Access Bank address map; the current value of the BSR is ignored entirely.
Using this “forced” addressing allows the instruction to operate on a data address in a single cycle,
without updating the BSR first. For 8-bit addresses of 60h and above, this means that users can evaluate
and operate on SFRs more efficiently. The Access RAM below 60h is a good place for data values that
the user might need to access rapidly, such as immediate computational results or common program
variables. Access RAM also allows for faster and more code efficient context saving and switching of
variables.
The mapping of the Access Bank is slightly different when the extended instruction set is enabled (XINST
Configuration bit = 1). This is discussed in more detail in the 10.5.3 Mapping the Access Bank in Indexed
Literal Offset Mode section.
10.3.3 General Purpose Register File
PIC18 devices may have banked memory in the GPR area. This is data RAM, which is available for use
by all instructions. GPRs start at the bottom of Bank 0 (address 000h) and grow upwards towards the
bottom of the SFR area. GPRs are not initialized by a Power-on Reset and are unchanged on all other
Resets.
10.3.4 Special Function Registers
The Special Function Registers (SFRs) are registers used by the CPU and peripheral modules for
controlling the desired operation of the device. These registers are implemented as static RAM. SFRs
start at the top of data memory (FFFh) and extend downward. A list of these registers is given in the
register summary table.
The SFRs can be classified into two sets: those associated with the “core” device functionality (ALU,
Resets and interrupts) and those related to the peripheral functions. The Reset and Interrupt registers are
described in their respective chapters, while the ALU’s STATUS register is described later in this section.
Registers related to the operation of a peripheral feature are described in the chapter for that peripheral.
The SFRs are typically distributed among the peripherals whose functions they control. Unused SFR
locations are unimplemented and read as ‘0’s.
Related Links
35. Register Summary
10.3.5 Status Register
The 10.8.5 STATUS register contains the arithmetic status of the ALU. As with any other SFR, it can be
the operand for any instruction.
If the STATUS register is the destination for an instruction that affects the Z, DC, C, OV or N bits, the
results of the instruction are not written; instead, the STATUS register is updated according to the
instruction performed. Therefore, the result of an instruction with the STATUS register as its destination
may be different than intended. As an example, CLRF STATUS will set the Z bit and leave the remaining
Status bits unchanged (‘000u u1uu’).
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It is recommended that only BCF, BSF, SWAPF, MOVFF and MOVWF instructions are used to alter the
STATUS register, because these instructions do not affect the Z, C, DC, OV or N bits in the STATUS
register.
For other instructions that do not affect Status bits, see the instruction set summaries.
Important:  The C and DC bits operate as the borrow and digit borrow bits, respectively, in
subtraction.
Related Links
37. Instruction Set Summary
10.4 Data Addressing Modes
Important:  The execution of some instructions in the core PIC18 instruction set are changed
when the PIC18 extended instruction set is enabled. See 10.5 Data Memory and the Extended
Instruction Set for more information.
Information in the data memory space can be addressed in several ways. For most instructions, the
Addressing mode is fixed. Other instructions may use up to three modes, depending on which operands
are used and whether or not the extended instruction set is enabled.
The Addressing modes are:
Inherent
Literal
Direct
Indirect
An additional Addressing mode, Indexed Literal Offset, is available when the extended instruction set is
enabled (XINST Configuration bit = 1). Its operation is discussed in greater detail in 10.5.1 Indexed
Addressing with Literal Offset.
10.4.1 Inherent and Literal Addressing
Many PIC18 control instructions do not need any argument at all; they either perform an operation that
globally affects the device or they operate implicitly on one register. This Addressing mode is known as
Inherent Addressing. Examples include SLEEP, RESET and DAW.
Other instructions work in a similar way but require an additional explicit argument in the opcode. This is
known as Literal Addressing mode because they require some literal value as an argument. Examples
include ADDLW and MOVLW, which respectively, add or move a literal value to the W register. Other
examples include CALL and GOTO, which include a 20-bit program memory address.
10.4.2 Direct Addressing
Direct Addressing specifies all or part of the source and/or destination address of the operation within the
opcode itself. The options are specified by the arguments accompanying the instruction.
In the core PIC18 instruction set, bit-oriented and byte-oriented instructions use some version of Direct
Addressing by default. All of these instructions include some 8-bit literal address as their Least Significant
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Byte. This address specifies either a register address in one of the banks of data RAM (see 10.3.3
General Purpose Register File) or a location in the Access Bank (see 10.3.2 Access Bank) as the data
source for the instruction.
The Access RAM bit ‘a’ determines how the address is interpreted. When ‘a’ is ‘1’, the contents of the
BSR (see 10.3.1 Bank Select Register) are used with the address to determine the complete 12-bit
address of the register. When ‘a’ is ‘0’, the address is interpreted as being a register in the Access Bank.
Addressing that uses the Access RAM is sometimes also known as Direct Forced Addressing mode.
A few instructions, such as MOVFF, include the entire 12-bit address (either source or destination) in their
opcodes. In these cases, the BSR is ignored entirely.
The destination of the operation’s results is determined by the destination bit ‘d’. When ‘d’ is ‘1’, the
results are stored back in the source register, overwriting its original contents. When ‘d’ is ‘0’, the results
are stored in the W register. Instructions without the ‘d’ argument have a destination that is implicit in the
instruction; their destination is either the target register being operated on or the W register.
10.4.3 Indirect Addressing
Indirect Addressing allows the user to access a location in data memory without giving a fixed address in
the instruction. This is done by using File Select Registers (FSRs) as pointers to the locations which are
to be read or written. Since the FSRs are themselves located in RAM as Special File Registers, they can
also be directly manipulated under program control. This makes FSRs very useful in implementing data
structures, such as tables and arrays in data memory.
The registers for Indirect Addressing are also implemented with Indirect File Operands (INDFs) that
permit automatic manipulation of the pointer value with auto-incrementing, auto-decrementing or
offsetting with another value. This allows for efficient code, using loops, such as the following example of
clearing an entire RAM bank.
Example 10-3. How to Clear RAM (Bank 1) Using Indirect Addressing
LFSR FSR0,100h ; Set FSR0 to beginning of Bank1
NEXT:
CLRF POSTINC0 ; Clear location in Bank1 then increment FSR0
BTFSS FSR0H,1 ; Has high FSR0 byte incremented to next bank?
BRA NEXT ; NO, clear next byte in Bank1
CONTINUE: ; YES, continue
10.4.3.1 FSR Registers and the INDF Operand
At the core of Indirect Addressing are three sets of registers: FSR0, FSR1 and FSR2. Each represents a
pair of 8-bit registers, FSRnH and FSRnL. Each FSR pair holds a 12-bit value, therefore, the four upper
bits of the FSRnH register are not used. The 12-bit FSR value can address the entire range of the data
memory in a linear fashion. The FSR register pairs, then, serve as pointers to data memory locations.
Indirect Addressing is accomplished with a set of Indirect File Operands, INDF0 through INDF2. These
can be thought of as “virtual” registers; they are mapped in the SFR space but are not physically
implemented. Reading or writing to a particular INDF register actually accesses its corresponding FSR
register pair. A read from INDF1, for example, reads the data at the address indicated by FSR1H:FSR1L.
Instructions that use the INDF registers as operands actually use the contents of their corresponding FSR
as a pointer to the instruction’s target. The INDF operand is just a convenient way of using the pointer.
Because Indirect Addressing uses a full 12-bit address, the FSR value can target any location in any
bank regardless of the BSR value. However, the Access RAM bit must be cleared to 0 to ensure that the
PIC18F26/45/46Q10
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INDF register in Access space is the object of the operation instead of a register in one of the other
banks. The assembler default value for the Access RAM bit is zero when targeting any of the indirect
operands.
10.4.3.2 FSR Registers and POSTINC, POSTDEC, PREINC and PLUSW
In addition to the INDF operand, each FSR register pair also has four additional indirect operands. Like
INDF, these are “virtual” registers that cannot be directly read or written. Accessing these registers
actually accesses the location to which the associated FSR register pair points, and also performs a
specific action on the FSR value. They are:
POSTDEC: accesses the location to which the FSR points, then automatically decrements the FSR
by 1 afterwards
POSTINC: accesses the location to which the FSR points, then automatically increments the FSR by
1 afterwards
PREINC: automatically increments the FSR by one, then uses the location to which the FSR points in
the operation
PLUSW: adds the signed value of the W register (range of -127 to 128) to that of the FSR and uses
the location to which the result points in the operation.
In this context, accessing an INDF register uses the value in the associated FSR register without
changing it. Similarly, accessing a PLUSW register gives the FSR value an offset by that in the W
register; however, neither W nor the FSR is actually changed in the operation. Accessing the other virtual
registers changes the value of the FSR register.
Figure 10-10. Indirect Addressing
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Rev. 30-000109A
4/18/2017
Operations on the FSRs with POSTDEC, POSTINC and PREINC affect the entire register pair; that is,
rollovers of the FSRnL register from FFh to 00h carry over to the FSRnH register. On the other hand,
results of these operations do not change the value of any flags in the STATUS register (e.g., Z, N, OV,
etc.).
PIC18F26/45/46Q10
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The PLUSW register can be used to implement a form of Indexed Addressing in the data memory space.
By manipulating the value in the W register, users can reach addresses that are fixed offsets from pointer
addresses. In some applications, this can be used to implement some powerful program control structure,
such as software stacks, inside of data memory.
10.4.3.3 Operations by FSRs on FSRs
Indirect Addressing operations that target other FSRs or virtual registers represent special cases. For
example, using an FSR to point to one of the virtual registers will not result in successful operations. As a
specific case, assume that FSR0H:FSR0L contains the address of INDF1. Attempts to read the value of
the INDF1 using INDF0 as an operand will return 00h. Attempts to write to INDF1 using INDF0 as the
operand will result in a NOP.
On the other hand, using the virtual registers to write to an FSR pair may not occur as planned. In these
cases, the value will be written to the FSR pair but without any incrementing or decrementing. Thus,
writing to either the INDF2 or POSTDEC2 register will write the same value to the FSR2H:FSR2L.
Since the FSRs are physical registers mapped in the SFR space, they can be manipulated through all
direct operations. Users should proceed cautiously when working on these registers, particularly if their
code uses Indirect Addressing.
Similarly, operations by Indirect Addressing are generally permitted on all other SFRs. Users should
exercise the appropriate caution that they do not inadvertently change settings that might affect the
operation of the device.
10.5 Data Memory and the Extended Instruction Set
Enabling the PIC18 extended instruction set (XINST Configuration bit = 1) significantly changes certain
aspects of data memory and its addressing. Specifically, the use of the Access Bank for many of the core
PIC18 instructions is different; this is due to the introduction of a new Addressing mode for the data
memory space.
What does not change is just as important. The size of the data memory space is unchanged, as well as
its linear addressing. The SFR map remains the same. Core PIC18 instructions can still operate in both
Direct and Indirect Addressing mode; inherent and literal instructions do not change at all. Indirect
addressing with FSR0 and FSR1 also remain unchanged.
10.5.1 Indexed Addressing with Literal Offset
Enabling the PIC18 extended instruction set changes the behavior of Indirect Addressing using the FSR2
register pair within Access RAM. Under the proper conditions, instructions that use the Access Bank –
that is, most bit-oriented and byte-oriented instructions – can invoke a form of Indexed Addressing using
an offset specified in the instruction. This special Addressing mode is known as Indexed Addressing with
Literal Offset, or Indexed Literal Offset mode.
When using the extended instruction set, this Addressing mode requires the following:
The use of the Access Bank is forced (‘a’ = 0) and
The file address argument is less than or equal to 5Fh.
Under these conditions, the file address of the instruction is not interpreted as the lower byte of an
address (used with the BSR in Direct Addressing), or as an 8-bit address in the Access Bank. Instead,
the value is interpreted as an offset value to an Address Pointer, specified by FSR2. The offset and the
contents of FSR2 are added to obtain the target address of the operation.
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10.5.2 Instructions Affected by Indexed Literal Offset Mode
Any of the core PIC18 instructions that can use Direct Addressing are potentially affected by the Indexed
Literal Offset Addressing mode. This includes all byte-oriented and bit-oriented instructions, or almost
one-half of the standard PIC18 instruction set. Instructions that only use Inherent or Literal Addressing
modes are unaffected.
Additionally, byte-oriented and bit-oriented instructions are not affected if they do not use the Access
Bank (Access RAM bit is ‘1’), or include a file address of 60h or above. Instructions meeting these criteria
will continue to execute as before. A comparison of the different possible Addressing modes when the
extended instruction set is enabled is shown in the following figure.
Those who desire to use byte-oriented or bit-oriented instructions in the Indexed Literal Offset mode
should note the changes to assembler syntax for this mode. This is described in more detail in the
Extended Instruction Syntax section.
PIC18F26/45/46Q10
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Figure 10-11. Comparing Addressing Options for Bit-Oriented and
Byte-Oriented Instructions (Extended Instruction Set Enabled)
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4/18/2017
PIC18F26/45/46Q10
Memory Organization
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 134
Related Links
37.2.1 Extended Instruction Syntax
10.5.3 Mapping the Access Bank in Indexed Literal Offset Mode
The use of Indexed Literal Offset Addressing mode effectively changes how the first 96 locations of
Access RAM (00h to 5Fh) are mapped. Rather than containing just the contents of the bottom section of
Bank 0, this mode maps the contents from a user defined “window” that can be located anywhere in the
data memory space. The value of FSR2 establishes the lower boundary of the addresses mapped into
the window, while the upper boundary is defined by FSR2 plus 95 (5Fh). Addresses in the Access RAM
above 5Fh are mapped as previously described (see 10.3.2 Access Bank). An example of Access Bank
remapping in this Addressing mode is shown in the following figure.
Figure 10-12. Remapping the Access Bank with Indexed Literal Offset Addressing
Data Memory
000h
100h
200h
F60h
F00h
FFFh
Bank 1
Bank 15
Bank 2
through
Bank 14
SFRs
ADDWF f, d, a
FSR2H:FSR2L = 120h
Locations in the region
from the FSR2 pointer
(120h) to the pointer plus
05Fh (17Fh) are mapped
to the bottom of the
Access RAM (000h-05Fh).
Special File Registers at
F60h through FFFh are
mapped to 60h through
FFh, as usual.
Bank 0 addresses below
5Fh can still be addressed
by using the BSR. Access Bank
00h
60h
FFh
SFRs
Bank 1 “Window”
Bank 0
Window
Example Situation:
120h
17Fh
5Fh
Bank 1
Rev. 30-000111A
4/18/2017
Remapping of the Access Bank applies only to operations using the Indexed Literal Offset mode.
Operations that use the BSR (Access RAM bit is ‘1’) will continue to use Direct Addressing as before.
10.6 PIC18 Instruction Execution and the Extended Instruction Set
Enabling the extended instruction set adds eight additional commands to the existing PIC18 instruction
set. These instructions are executed as described in the Extended Instruction Set section.
Related Links
37.2.1 Extended Instruction Syntax
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10.7 Register Summary: Memory and Status
Address Name Bit Pos.
0x0FD8 STATUS 7:0 TO PD N OV Z DC C
0x0FD9 FSR2
7:0 FSRL[7:0]
15:8 FSRH[3:0]
0x0FDB PLUSW2 7:0 PLUSW[7:0]
0x0FDC PREINC2 7:0 PREINC[7:0]
0x0FDD POSTDEC2 7:0 POSTDEC[7:0]
0x0FDE POSTINC2 7:0 POSTINC[7:0]
0x0FDF INDF2 7:0 INDF[7:0]
0x0FE0 BSR 7:0 BSR[3:0]
0x0FE1 FSR1
7:0 FSRL[7:0]
15:8 FSRH[3:0]
0x0FE3 PLUSW1 7:0 PLUSW[7:0]
0x0FE4 PREINC1 7:0 PREINC[7:0]
0x0FE5 POSTDEC1 7:0 POSTDEC[7:0]
0x0FE6 POSTINC1 7:0 POSTINC[7:0]
0x0FE7 INDF1 7:0 INDF[7:0]
0x0FE8 WREG 7:0 WREG[7:0]
0x0FE9 FSR0
7:0 FSRL[7:0]
15:8 FSRH[3:0]
0x0FEB PLUSW0 7:0 PLUSW[7:0]
0x0FEC PREINC0 7:0 PREINC[7:0]
0x0FED POSTDEC0 7:0 POSTDEC[7:0]
0x0FEE POSTINC0 7:0 POSTINC[7:0]
0x0FEF INDF0 7:0 INDF[7:0]
0x0FF0
...
0x0FF8
Reserved
0x0FF9 PCL 7:0 PCL[7:0]
0x0FFA PCLAT
7:0 PCLATH[7:0]
15:8 PCLATU[4:0]
0x0FFC STKPTR 7:0 STKPTR[4:0]
0x0FFD TOS
7:0 TOSL[7:0]
15:8 TOSH[7:0]
23:16 TOSU[4:0]
10.8 Register Definitions: Memory and Status
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10.8.1 PCL
Name:  PCL
Address:  0xFF9
Low byte of the Program Counter
Bit 7 6 5 4 3 2 1 0
PCL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – PCL[7:0]
Provides direct read and write access to the Program Counter
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10.8.2 PCLAT
Name:  PCLAT
Address:  0xFFA
Program Counter Latches. Holding register for bits <21:9> of the Program Counter (PC). Reads of the
PCL register transfer the upper PC bits to the PCLAT register. Writes to PCL register transfer the PCLAT
value to the PC.
Bit 15 14 13 12 11 10 9 8
PCLATU[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
PCLATH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 12:8 – PCLATU[4:0] Upper PC Latch register
Holding register for Program Counter bits <21:17>
Bits 7:0 – PCLATH[7:0] High PC Latch register
Holding register for Program Counter bits <16:8>
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10.8.3 TOS
Name:  TOS
Address:  0xFFD
Top-Of-Stack Registers.
Contents of the stack pointed to by the 10.8.4 STKPTR register. This is the value that will be loaded into
the Program Counter upon a RETURN or RETFIE instruction.
Bit 23 22 21 20 19 18 17 16
TOSU[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bit 15 14 13 12 11 10 9 8
TOSH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
TOSL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 20:16 – TOSU[4:0] Upper byte of TOS register
Bits <21:17> of the TOS
Bits 15:8 – TOSH[7:0] High Byte of the TOS Register
Bits <16:8> of the TOS
Bits 7:0 – TOSL[7:0] Low Byte TOS Register
Bits <7:0> of the TOS
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10.8.4 STKPTR
Name:  STKPTR
Address:  0xFFC
Stack Pointer Register
Bit 7 6 5 4 3 2 1 0
STKPTR[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – STKPTR[4:0] Stack Pointer Location bits
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10.8.5 STATUS
Name:  STATUS
Address:  0xFD8
Status Register
Bit 7 6 5 4 3 2 1 0
TO PD N OV Z DC C
Access R R R/W R/W R/W R/W R/W
Reset 1 1 0 0 0 0 0
Bit 6 – TO Time-Out bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1Set at power-up or by execution of CLRWDT or SLEEP instruction
0A WDT time-out occurred
Bit 5 – PD Power-Down bit
Reset States: POR/BOR = 1
All Other Resets = q
Value Description
1Set at power-up or by execution of CLRWDT instruction
0Cleared by execution of the SLEEP instruction
Bit 4 – N Negative bit
Used for signed arithmetic (2’s complement); indicates if the result is negative,
(ALU MSb = 1).
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1The result is negative
0The result is positive
Bit 3 – OV Overflow bit
Used for signed arithmetic (2’s complement); indicates an overflow of the 7-bit magnitude, which causes
the sign bit (bit 7) to change state.
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Overflow occurred for current signed arithmetic operation
0No overflow occurred
Bit 2 – Z Zero bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1The result of an arithmetic or logic operation is zero
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Value Description
0The result of an arithmetic or logic operation is not zero
Bit 1 – DC Digit Carry/Borrow bit
ADDWF, ADDLW, SUBLW, SUBWF instructions(1)
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1A carry-out from the 4th low-order bit of the result occurred
0No carry-out from the 4th low-order bit of the result
Bit 0 – C Carry/Borrow bit
ADDWF, ADDLW, SUBLW, SUBWF instructions(1,2)
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1A carry-out from the Most Significant bit of the result occurred
0No carry-out from the Most Significant bit of the result occurred
Note: 
1. For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of
the second operand.
2. For Rotate (RRCF, RLCF) instructions, this bit is loaded with either the high or low-order bit of the
Source register.
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10.8.6 WREG
Name:  WREG
Address:  0xFE8
Shadow of Working Data Register
Bit 7 6 5 4 3 2 1 0
WREG[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 7:0 – WREG[7:0]
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10.8.7 INDF
Name:  INDFx
Address:  0xFEF,0xFE7,0xFDF
Indirect Data Register. This is a virtual register. The GPR/SFR register addressed by the FSRx register is
the target for all operations involving the INDFx register.
Bit 7 6 5 4 3 2 1 0
INDF[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – INDF[7:0]
Indirect data pointed to by the FSRx register
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10.8.8 POSTDEC
Name:  POSTDECx
Address:  0xFED,0xFE5,0xFDD
Indirect Data Register with post decrement. This is a virtual register. The GPR/SFR register addressed by
the FSRx register is the target for all operations involving the POSTDECx register. FSRx is decrememted
after the read or write operation.
Bit 7 6 5 4 3 2 1 0
POSTDEC[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – POSTDEC[7:0]
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 145
10.8.9 POSTINC
Name:  POSTINCx
Address:  0xFEE,0xFE6,0xFDE
Indirect Data Register with post increment. This is a virtual register. The GPR/SFR register addressed by
the FSRx register is the target for all operations involving the POSTINCx register. FSRx is incremented
after the read or write operation.
Bit 7 6 5 4 3 2 1 0
POSTINC[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – POSTINC[7:0]
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10.8.10 PREINC
Name:  PREINCx
Address:  0xFEC,0xFE4,0xFDC
Indirect Data Register with pre-increment. This is a virtual register. The GPR/SFR register addressed by
the FSRx register plus 1 is the target for all operations involving the PREINCx register. FSRx is
incremented before the read or write operation.
Bit 7 6 5 4 3 2 1 0
PREINC[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – PREINC[7:0]
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10.8.11 PLUSW
Name:  PLUSWx
Address:  0xFEB,0xFE3,0xFDB
Indirect Data Register with WREG offset. This is a virtual register. The GPR/SFR register addressed by
the sum of the FSRx register plus the signed value of the W register is the target for all operations
involving the PLUSWx register.
Bit 7 6 5 4 3 2 1 0
PLUSW[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – PLUSW[7:0]
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10.8.12 FSR
Name:  FSRx
Address:  0xFE9,0xFE1,0xFD9
Indirect Address Register. The FSR value is the address of the data to which the INDF register points.
Bit 15 14 13 12 11 10 9 8
FSRH[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 6 5 4 3 2 1 0
FSRL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 11:8 – FSRH[3:0]
Most Significant address of INDF data
Bits 7:0 – FSRL[7:0]
Least Significant address of INDF data
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10.8.13 BSR
Name:  BSR
Address:  0xFE0
Bank Select Register
The BSR indicates the data memory bank which is bits 11:8 of the GPR address.
Bit 7 6 5 4 3 2 1 0
BSR[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – BSR[3:0]
Four Most Significant bits of the data memory address
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11. (NVM) Nonvolatile Memory Control
Nonvolatile memory is separated into three categories: Program Flash Memory (PFM) including User IDs,
Configuration Words, and Data Flash Memory (DFM). DFM is also referred to as EEPROM because it is
written one byte at a time and the erase before write is automatic. Although User IDs are above the PFM
section they are included in the PFM category because the read and write access is identical for both.
The write and erase times are controlled by an on-chip timer. The write and erase voltages are generated
by an on-chip charge pump rated to function over the operating voltage range of the device.
PFM and DFM can be protected in two ways: code protection and write protection. Code protection
(Configuration bits CP for PFM and CPD for DFM) disables read and write access through an external
device programmer. Code protection does not affect the self-write and erase functionality whereas write
protection does. Code protection write protection can only be reset by a Bulk Erase performed by an
external device programmer. A PFM Bulk Erase clears the program space, Configuration bits, and User
IDs. A Bulk Erase only clears DFM if the CPD = 0. When CPD = 1 then bulk erasing DFM requires setting
the Program Counter to the DFM area before the Bulk Erase command is issued, and then only the DFM
area is cleared. See the programming specification for more details. Write protection prevents writes to
NVM areas tagged for protection by the WRTn Configuration bits. Attempts to write a protected location
will set the NVMERR bit.
PFM and Configuration Words can be accessed by either the Table Pointer or NVM controls. DFM can be
accessed only by the NVM controls. The PFM access is by single byte, single word, or full sector. A
sector is 256 bytes (128 PFM words). The sector memory occupies one full bank of RAM space located in
the RAM bank following the last occupied GPR bank. Sector memory is also referred to elsewhere in this
document as the write block holding registers. The Table Pointer accesses memory by bytes. The NVM
control accesses the DFM section by bytes and the other sections by words and sectors.
The NVM controls include five independent access functions with five corresponding control bits. The
controls are as follows:
RD – Single byte/word read
WR – single byte/word write
SECRD – Sector read
SECWR – Sector write
SECER – Sector erase
The NVMADR registers determine the address of the memory region being accessed by the NVM control.
The TBLPTR registers determine the address of the memory being accessed by the Table Pointer
functions. The following table indicates which controls operate in each region.
Table 11-1. NVM Organization Table
Region Address
Range
Table
Pointer
TBLRD
NVMCON1
RD WR SECRD SECWR SECER
PFM 00 0000h
01 FFFFh ●●●●●●
User IDs 20 0000h
20 00FFh ●●●●●●
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 151
...........continued
Region Address
Range
Table
Pointer
TBLRD
NVMCON1
RD WR SECRD SECWR SECER
CONFIG 30 0000h
30 000Bh
DFM 31 0000h
31 00FFh
11.1 Program Flash Memory
The Program Flash Memory is readable, writable, and erasable during normal operation over the entire
VDD range.
A read from program memory is executed one byte at a time. A program memory erase is executed on
blocks of n bytes at a time, also referred to as sectors. Refer to the following table for write and erase
block sizes. A Bulk Erase operation cannot be issued from user code. A write to program memory can be
executed by sectors or single words.
Table 11-2. Flash Memory Organization by Device
Device Sector Erase
Size (Words)
Holding
Registers
(Bytes)
TBLPTR LSbs
(Holding
Address)
Program Flash
Memory
(Words)
Data Flash
Memory
(Bytes)
PIC18F26Q10
128 256 8
32768 1024
PIC18F46Q10
PIC18F45Q10 16384 256
Writing or erasing program memory will cease instruction fetches until the operation is complete. The
program memory cannot be accessed during the write or erase, therefore, code cannot execute. An
internal programming timer terminates program memory writes and erases.
A value written to program memory does not need to be a valid instruction. Executing a program memory
location that forms an invalid instruction results in a NOP.
It is important to understand the PFM memory structure for erase and programming operations. Program
memory word size is 16 bits wide. PFM is arranged in sectors. A sector is the minimum size that can be
erased by user software.
After a sector has been erased, all or a portion of this sector can be programmed. Data can be written
directly into PFM one 16-bit word at a time using the NVMADR and NVMCON1 controls or as a full sector
from sector RAM, which is also referred to as the holding registers. These 8-bit registers are located in
the RAM bank following the last GPR RAM bank. The holding registers are directly accessible as any
other SFR/GPR register and also may be loaded via sequential writes using the TABLAT and 11.5.7
TBLPTR registers.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 152
Important:  To modify only a portion of a previously programmed sector the contents of the
entire sector must be read and saved in RAM prior to the sector erase. The SECRD operation is
the easiest way to do this. Then, the new data can be written into the holding registers to
reprogram the sector of PFM. However, any unprogrammed locations can be written using the
single word write operation without first erasing the sector.
11.1.1 Table Pointer Operations
In order to read and write program memory, there are two operations that allow the processor to move
bytes between the program memory space and the data RAM:
Table Read (TBLRD*)
Table Write (TBLWT*)
The SFR registers associated with these operations include:
TABLAT register
TBLPTR registers
The program memory space is 16 bits wide, while the data RAM space is eight bits wide. The TBLPTR
registers determine the address of one byte of the NVM memory. Table reads move one byte of data from
NVM space to the TABLAT register and table writes move the TABLAT data to a holding register ready for
a subsequent write to NVM space with the NVM controls.
11.1.1.1 Table Pointer Register
The Table Pointer (TBLPTR) register addresses a byte within the program memory. The TBLPTR
comprises three SFR registers: Table Pointer Upper Byte, Table Pointer High Byte and Table Pointer Low
Byte (TBLPTRU:TBLPTRH:TBLPTRL). These three registers join to form a 22-bit wide pointer (bits 0
through 21). The bits 0 through 20 allow the device to address up to 2 Mbytes of program memory space.
Bit 21 allows access to the Device ID, the User ID and the Configuration bits.
The Table Pointer register, TBLPTR, is used by the TBLRD and TBLWT instructions. These instructions
can increment and decrement the TBLPTR depending on specific appended characters as shown in the
following table. The increment and decrement operations on the TBLPTR affect only bits 0 through 20.
Table 11-3. Table Pointer Operations with TBLRD and TBLWT Instructions
Example Operation on Table Pointer
TBLRD*
TBLWT* TBLPTR is not modified
TBLRD*+
TBLWT*+ TBLPTR is incremented after the read/write
TBLRD*-
TBLWT*- TBLPTR is decremented after the read/write
TBLRD+*
TBLWT+* TBLPTR is incremented before the read/write
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 153
11.1.1.2 Table Latch Register
The Table Latch (TABLAT) is an 8-bit register mapped into the SFR space. The Table Latch register
receives one byte of NVM data resulting from a TBLRD* instruction and is the source of the 8-bit data
sent to the holding register space as a result of a TBLWT* instruction.
11.1.1.3 Table Read Operations
The table read operation retrieves one byte of data directly from program memory pointed to by the
TBLPTR registers and places it into the TABLAT register. Figure 11-1 shows the operation of a table read.
Figure 11-1. Table Read Operation
Table Pointer(1)
Table Latch (8-bit)
Program Memory
TBLPTRH TBLPTRL
TABLAT
TBLPTRU
Instruction: TBLRD*
Note 1: Table Pointer register points to a byte in program memory.
Program Memory
(TBLPTR)
Rev. 30-000002A
3/22/2017
11.1.1.4 Table Write Operations
The table write operation stores one byte of data from the TABLAT register into a sector RAM holding
register. The following figure shows the operation of a table write from the TABLAT register to the holding
register space. The procedure to write the contents of the holding registers into program memory is
detailed in the "Writing to Program Flash Memory" section.
Figure 11-2. Table Write Operation
Table Pointer(1) Table Latch (8-bit)
TBLPTRH TBLPTRL TABLAT
Program Memory
(TBLPTR<MSbs>)
TBLPTRU
Instruction: TBLWT*
Note 1: During table writes the Table Pointer points to two areas. The LSbs of TBLPRTL point to an address
within the sector RAM space. The MSbs of the Table Pointer determine where the sector will eventually
be written.
Program Memory Sector RAM
Rev. 30-000003B6/23/2017
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 154
Table operations work with byte entities. Tables containing data, rather than program instructions, are not
required to be word-aligned. Therefore, a table can start and end at any byte address. If a table write is
being used to write executable code into program memory, program instructions will need to be word-
aligned.
Related Links
11.1.4 Writing to Program Flash Memory
11.1.1.5 Table Pointer Boundaries
TBLPTR is used in reads, writes and erases of the Program Flash Memory.
When a TBLRD is executed, all 22 bits of the TBLPTR determine which byte is read from program
memory directly into the TABLAT register.
When a TBLWT is executed the byte in the TABLAT register is written, not to Flash memory, but to a
holding register in preparation for a program memory write. The holding registers constitute a write block,
which may vary depending on the device (see the "Flash Memory Organization by Device" table in the
"Program Flash Memory" section). The LSbs of the TBLPTRL register determine which specific address
within the holding register block is written to. The size of the write block determines the number of LSbs.
The MSbs of the Table Pointer have no effect during TBLWT operations.
When a PFM sector write is executed the entire holding register block is written to the Flash memory
sector at the address determined by the MSbs of the NVMADR. The LSbs are ignored during sector
writes. For more detail, see the 11.1.4 Writing to Program Flash Memory section.
The following figure illustrates the relevant boundaries of TBLPTR and NVMADR based on NVM control
operations.
Figure 11-3. Table Pointer Boundaries Based on Operation
21 16 15 8 7 0
TBLPTRL
TBLPTR<n:0>(1)
NVMADR<21:n+1>
(1)
SECTOR ERASE/WRITE
TABLE READ – TBLPTR<21:0>
TABLE WRITE
NVMADRH
NVMADRU
TBLPTRHTBLPTRU
TBLPTRL
Rev. 30-000004B
5/11/2017
Note: 
1. See the "Flash Memory Organization by Device" table in the "Program Flash Memory" section for
the write holding registers block size.
Related Links
11.1 Program Flash Memory
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 155
11.1.1.6 Reading the Program Flash Memory
The TBLRD instruction retrieves data from program memory at the TBLPTR location and places it into the
TABLAT SFR register. Table reads from program memory are performed one byte at a time. In addition,
TBLPTR can be modified automatically for the next table read operation.
The CPU operation is suspended during the read, and it resumes immediately after. From the user point
of view, TABLAT is valid in the next instruction cycle.
The internal program memory is typically organized by words. The Least Significant bit of the address
selects between the high and low bytes of the word. Figure 11-4 shows the interface between the internal
program memory and the TABLAT.
Figure 11-4. Reads from Program Flash Memory
(Even Byte Address)
Program Memory
(Odd Byte Address)
TBLRD TABLAT
TBLPTR = xxxxx1
FETCH
Instruction Register
(IR) Read Register
TBLPTR = xxxxx0
Rev. 30-000006A
3/22/2017
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 156
Figure 11-5. Program Flash Memory Read Flowchart
Filename: 10-000046B.vsd
Title: FLASH PROGRAM MEMORY READ FLOWCHART
Last Edit: 8/10/2016
First Used: PIC16F1508/9
Note:
Start
Read Operation
Select Word Address
(TBLPTR registers)
Initiate Read operation
(TBLRD)
Data read now in
TABLAT register
End
Read Operation
Rev. 10-000 046B
8/10/201 6
Example 11-1. Reading a Program Flash Memory Word
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base
MOVWF TBLPTRU ; address of the word
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
READ_WORD:
TBLRD*+ ; read into TABLAT and increment
MOVF TABLAT, W ; get data
MOVWF WORD_EVEN
TBLRD*+ ; read into TABLAT and increment
MOVFW TABLAT, W ; get data
MOVF WORD_ODD
11.1.2 NVM Unlock Sequence
The unlock sequence is a mechanism that protects the NVM from unintended self-write programming,
sector reads, and erasing. The sequence must be executed and completed without interruption to
successfully complete any of the following operations:
PFM sector erase
PFM sector write from holding registers
PFM sector read into write block holding registers
PFM word write directly to NVM
DFM byte write directly to NVM
Write to Configuration Words
Each of these operations correspond to one of four unlock code sequences as shown in the following
table:
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(NVM) Nonvolatile Memory Control
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Table 11-4. NVM Unlock Codes
Operation First Unlock Byte Second Unlock Byte NVMCON1
Operation Bit
Word/Byte write 55h AAh WR
Sector write DDh 22h SECWR
Sector erase CCh 33h SECER
Sector read BBh 44h SECRD
The general unlock sequence consists of the following steps and must be completed in order:
Write first unlock byte to NVMCON2
Write second unlock byte to NMVCON2
Set the operation control bit of NVMCON1
For PFM and Configuration Word operations, once the control bit is set the processor will stall internal
operations until the operation is complete and then resume with the next instruction. DFM operations do
not stall the CPU.
Since the unlock sequence must not be interrupted, global interrupts should be disabled prior to the
unlock sequence and re-enabled after the unlock sequence is completed.
Figure 11-6. NVM Unlock Sequence Flowchart
End Unlock Operation
Start Unlock Sequence
Set NVMCON1 control bit to
Initiate write or erase operation
Write first unlock byte
to NVMCON2
Write second unlock byte
to NVMCON2
Rev. 30-000005B
4/27/2017
Example 11-2. NVM Unlock Sequence for PFM word write
BCF INTCON,GIE ; Recommended so sequence is not interrupted
MOVF UpperAddr,W ; set the target address
MOVWF NVMADRU
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 158
MOVF HighAddr,W
MOVWF NVMADRH
MOVF LowAddr,W
MOVWF NVMADRL
MOVF HighByte,W ; high byte of word to be written
MOVWF NVMDATH ; store in high byte transfer register
MOVF LowByte,W ; low byte of word to be written
MOVWF NVMDATL ; store in low byte transfer register
BSF NVMCON0,NVMEN ; Enable NVM operation
MOVLW 55h ; Load first unlock byte
; –------------------ Required Sequence –-----------------------------
MOVWF NVMCON2 ; Step 1: Load first byte into NVMCON2
MOVLW AAh ; Step 2: Load W with second unlock byte
MOVWF NVMCON2 ; Step 3: Load second byte into NVMCON2
BSF NVMCON1,WR ; Step 4: Set WR bit to begin write
; –-------------------------------------------------------------------
BSF INTCON,GIE ; Re-enable interrupts
Important: 
1. Sequence begins when NVMCON2 is written; steps 1-4 must occur in the cycle-accurate
order shown. If the timing of the steps 1 to 4 is corrupted by an interrupt or a debugger
halt, the action will not take place.
2. Opcodes shown are illustrative; any instruction that has the indicated effect may be used.
11.1.3 Erasing Program Flash Memory (PFM)
The minimum erase block is always one sector. Only through the use of an external programmer, or
through ICSP control, can larger blocks of program memory be Bulk Erased. Word erase in the Flash
array is not supported.
For example, when initiating an erase sequence from a microcontroller with sector erase size of 128
words, a block of 128 words (256 bytes) of program memory is erased. The NVMADR<21:8> bits point to
the block being erased. The NVMADR<7:0> bits are ignored.
The NVMCON0 and NVMCON1 registers command the erase operation. The NVMEN bit must be set to
enable write operations. The SECER bit is set to initiate the erase operation.
The NVM unlock sequence described in the 11.1.2 NVM Unlock Sequence section must be used, which
guards against accidental writes. This is sometimes referred to as a long write.
A long write is necessary for erasing the internal Flash. Instruction execution is halted during the long
write cycle. The long write is terminated by the internal programming timer.
11.1.3.1 PFM Erase Sequence
The sequence of events for erasing a block of internal program memory is:
1. Set NVMADR to an address within the intended sector.
2. Set the NVMEN bit to enable NVM
3. Perform the unlock sequence as described the 11.1.2 NVM Unlock Sequence section
4. Set the SECER bit
If the PFM address is write-protected, the SECER bit will be cleared and the erase operation will not take
place, NVMERR is signaled in this scenario.
The operation erases the sector indicated by masking the LSbs of the current NVMADR.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 159
While erasing PFM, CPU operation is suspended and it resumes when the operation is complete. Upon
completion the SECER bit is cleared in hardware, the NVMIF is set and an interrupt will occur if the
NVMIE bit is also set.
The holding register data are not affected by erase operations and NVMEN will remain unchanged.
Figure 11-7. PFM Sector Erase Flowchart
Unlock Sequence
End Erase Operation
Disable Write/Erase Operation
Load NVMADR registers with
CPU stalls while Erase operation
Disable Interrupts
Enable Interrupts
Enable Write/Erase Operation
Rev/ 30-000007B
5/1/2017
address of the block being erased
Start Erase Operation
completes (10 ms typical)
Select Erase Operation
(GIE = 1)
(NVMEN =1)
(GIE = 1)
(SECER = 1)
Sector Erase
(NVMEN = 0)
Example 11-3. Erasing a Program Flash Memory block
; This sample sector erase routine assumes that the target address
; specified by CODE_ADDR_UPPER and CODE_ADDR_HIGH contain a value within
; the PFM address range of the device.
MOVLW CODE_ADDR_UPPER ; load NVMADR with the base
MOVWF NVMADRU ; address of the memory block
MOVLW CODE_ADDR_HIGH
MOVWF NVMADRH
ERASE_BLOCK:
BSF NVMCON0, NVMEN ; enable Program Flash Memory
BCF INTCON, GIE ; disable interrupts
Required MOVLW CCh ; first unlock byte for erase
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Sequence MOVWF NVMCON2 ; write CCh
MOVLW 33h ; second unlock byte for erase
MOVWF NVMCON2 ; write 33h
BSF NVMCON1, SECER ; start erase (CPU stalls)
BSF INTCON, GIE ; re-enable interrupts
BCF NVMCON0, NVMEN ; disable writes to memory
Important: 
1. If a write or erase operation is terminated by an unexpected event, NVMERR bit will be
set which the user can check to decide whether a rewrite of the location(s) is needed.
2. NVMERR is set if SECER is written to ‘1’ while NVMADR points to a write-protected
address.
3. NVMERR is set if SECER is written to ‘1’ while NVMADR points to an invalid address
location ( Refer to the device memory map and NVM Organization Table).
Related Links
11. (NVM) Nonvolatile Memory Control
11.1.4 Writing to Program Flash Memory
Program memory can be written either one word at a time or a sector at a time.
A single word is written by setting the NVMADR to the target address and loading NVMDAT with the
desired word. The word is then transferred to Flash memory with the WR unlock and write sequence.
A sector is written by first loading a block of holding registers and then executing a sector write sequence.
The programming write block size is specified as the holding registers, also referred to as sector RAM, in
the Flash memory organization by device table. Table writes are used to write the holding register bytes
that are then transferred to Flash memory with the SECWR unlock and write sequence. There are only as
many holding registers as there are bytes in a write block.
Since the table latch (11.5.6 TABLAT) is only a single byte, the TBLWT instruction needs to be executed
multiple times for each sector programming operation. The write protection state is ignored for table
writes. All of the table write operations will essentially be short writes because only the holding registers
are written. NVMIF is not affected while writing to the holding registers.
After all the holding registers have been written, the programming operation of that sector of memory is
started by setting NVMADR to an address within the target sector and executing a sector write unlock
sequence followed immediately by setting the SECWR bit.
If the PFM address in the NVMADR is write-protected, or if NVMADR points to an invalid location, the
SECWR bit is cleared without any effect and the NVMERR is set.
CPU operation is suspended during a long write cycle and resumes when the operation is complete. The
long write operation completes in one extended instruction cycle. When complete, the SECWR or WR bit
is cleared by hardware and NVMIF is set. An interrupt will occur if NVMIE is also set. The holding
registers are unchanged. NVMEN is not changed.
The internal programming timer controls the write time. The write/erase voltages are generated by an on-
chip charge pump, rated to operate over the voltage range of the device.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 161
Important:  The holding registers are undefined on device Resets and unchanged after write
operations. Individual bytes of program memory may be modified, provided that the modification
does not attempt to change any bit from a ‘0’ to a ‘1’. When modifying individual bytes with a
sector write operation, it is necessary to load all holding registers with either FFh or the existing
contents of memory before executing a long write operation. The fastest way to do this is by
performing a sector read operation.
Figure 11-8. Table Writes to Program Flash Memory
TABLAT
TBLPTR = xxxxYY(1)
TBLPTR = xxxx01TBLPTR = xxxx00
Write Register
TBLPTR = xxxx02
Program Memory
Holding Register Holding Register Holding Register Holding Register
88 8 8
Rev. 30-000008A
3/22/2017
Note:  Refer to Flash memory organization by device table for number of holding registers (e.g. YY =
FFh for 256 holding registers).
Related Links
11.1 Program Flash Memory
11.1.4.1 PFM Sector Write Sequence
The sequence of events for programming a block of internal program memory location should be:
1. Set NVMADR with the target sector address.
2. Read the PFM sector into RAM with the SECRD operation.
3. Execute the sector erase procedure (see 11.1.3.1 PFM Erase Sequence).
4. SECER is set as the last step in the erase sequence.
5. The CPU will stall for the duration of the erase (about 10 ms using internal timer).
6. Load TBLPTR with address of first byte being updated.
7. Write the n-byte block into the holding registers with auto-increment. Refer to the Flash memory
organization by device table for the number of holding registers.
8. Disable interrupts.
9. Execute the sector write unlock sequence (see 11.1.2 NVM Unlock Sequence).
10. SECWR bit is set as last step in the unlock sequence.
11. The CPU will stall for the duration of the write (about 10 ms using internal timer).
12. Re-enable interrupts.
13. Verify the memory (table read).
This procedure will require about 20 ms to update each block of memory. See the "Memory Programming
Specifications" for more detail. An example of the required code is given below.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
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Important:  Before setting the SECWR bit, the NVMADR value needs to be within the intended
address range of the target PFM sector.
Figure 11-9. Program Flash Memory (PFM) Write Flowchart
Start
Write Operation
End
Write Operation
CPU stalls while Write
operation completes
(10 ms typical)
No delay when writing to
PFM Latches
Determine number of
bytes to be written into
PFM. The number of
bytes cannot exceed the
number of bytes per
sector (byte_cnt)
Last byte written?
Set NVMADR to address
within target sector
Perform SECRD operation
Erase target PFM sector
with SECER operation
Load TABLAT with the
value to write
Update the byte counter
(byte_cnt--)
Disable NVM
(NVMEN = 0)
Yes
No
Rev. 10-000049D
12/15/2017
Write byte to sector RAM
with TBLWT*+
Set TBLPTR to PFM
address of first byte
Disable Interrupts
(GIE = 0)
Perform SECWR operation
Re-enable Interrupts
(GIE = 1)
CPU stalls while Erase
operation completes
(10 ms typical)
Example 11-4. Writing a Sector of Program Flash Memory
; Code sequence to modify one word in a programmed sector of PFM
; Calling routine should check WREG for the following errors:
;
; 00h = Successful modification
; 01h = Read error
; 02h = Erase error
; 03h = Write error
;
READ_BLOCK:
MOVLW CODE_ADDR_UPPER ; load NVMADR with the base
MOVWF NVMADRU ; address of the memory sector
MOVLW CODE_ADDR_HIGH
PIC18F26/45/46Q10
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MOVWF NVMADRH
MOVLW CODE_ADDR_LOW
MOVWF NVMADRL
BCF INTCON, GIE ; disable interrupts
BSF NVMCON0, NVMEN ; enable NVM
; ----- Required Sequence -----
MOVLW 0BBh
MOVWF NVMCON2 ; first unlock byte = 0BBh
MOVLW 44h
MOVWF NVMCON2 ; second unlock byte = 44h
BSF NVMCON1, SECRD ; start sector read (CPU stall)
; ------------------------------
BTFSC NVMCON0, NVMERR ; Verify no error occurred during read
BRA NVM_RDERR ; return read error code
ERASE_BLOCK: ; NVMADR is already pointing to target
block
; ----- Required Sequence -----
MOVLW 0CCh
MOVWF NVMCON2 ; first unlock byte = 0CCh
MOVLW 33h
MOVWF NVMCON2 ; second unlock byte = 33h
BSF NVMCON1, SECER ; start sector erase (CPU stall)
; ------------------------------
BTFSC NVMCON0, NVMERR ; Verify no error occurred during erase
BRA NVM_ERERR ; return erase error code
MODIFY_WORD:
MOVLW TARGET_ADDR_UPPER ; load TBLPTR with the target address
MOVWF TBLPTRU ; of the LSByte
MOVLW TARGET_ADDR_HIGH
MOVWF TBLPTRH
MOVLW TARGET_ADDR_LOW
MOVWF TBLPTRL
MOVLW NEW_DATA_LOW ; update holding register
MOVWF TABLAT
TBLWT*+
MOVLW NEW_DATA_HIGH
MOVWF TABLAT
TBLWT*+
PROGRAM_MEMORY: ; NVMADR is already pointing to target
block
; ----- Required Sequence -----
MOVLW 0DDh
MOVWF NVMCON2 ; first unlock byte = 0DDh
MOVLW 22h
MOVWF NVMCON2 ; second unlock byte = 22h
BSF NVMCON1, SECWR ; start sector programming (CPU stall)
; ------------------------------
BTFSC NVMCON0, NVMERR ; Verify no error occurred during write
BRA NVM_WRERR ; return sector write error code
CLRF WREG,F ; return with no error
BRA NVM_EXIT
NVM_RDERR:
MOVLW 01h
BRA NVM_EXIT
NVM_ERERR:
MOVLW 02h
BRA NVM_EXIT
NVM_WRERR:
MOVLW 03h
NVM_EXIT:
BCF NVMCON0, NVMEN ; disable NVM
BSF INTCON, GIE ; re-enable interrupts
RETURN
Related Links
39.3.5 Memory Programming Specifications
11.1.4.2 PFM Word Write Sequence
The sequence of events for programming an erased single word of internal program memory location
should be:
1. Set NVMADR with the target word address.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 164
2. Load NVMDAT with desired word.
3. Disable interrupts.
4. Execute the word/byte write unlock sequence (see 11.1.2 NVM Unlock Sequence).
5. WR bit is set as last step in the unlock sequence.
6. The CPU will stall for the duration of the write (about 50 μs using internal timer).
7. Re-enable interrupts.
8. Verify the memory (word read).
Example 11-5. Writing a Word of Program Flash Memory
; Code sequence to program one erased word of PFM
; Target address is in WORD_ADDR_UPPER:WORD_ADDR_HIGH:WORD_ADDR_LOW
; Target data is in WORD_HIGH_BYTE:WORD_LOW_BYTE
; Calling routine should check WREG for the following errors:
;
; 00h = Successful modification
; 03h = Write error
;
WORD_WRITE:
MOVF WORD_ADDR_UPPER, W ; load NVMADR with the target
MOVWF NVMADRU ; address of the word
MOVF WORD_ADDR_HIGH, W
MOVWF NVMADRH
MOVF WORD_ADDR_LOW, W
MOVWF NVMADRL
MOVF WORD_HIGH_BYTE, W ; load NVMDAT with desired
MOVWF NVMDATH ; word
MOVF WORD_LOW_BYTE, W
MOVWF NVMDATL
BCF INTCON, GIE ; disable interrupts
BSF NVMCON0, NVMEN ; enable NVM
PROGRAM_WORD:
; ----- Required Sequence -----
MOVLW 055h
MOVWF NVMCON2 ; first unlock byte = 055h
MOVLW 0AAh
MOVWF NVMCON2 ; second unlock byte = 0AAh
BSF NVMCON1, WR ; start word programming (CPU stall)
; ------------------------------
BTFSC NVMCON0, NVMERR ; Verify no error occurred during write
BRA NVM_WRERR ; return sector write error code
VERIFY_WORD:
BSF NVMCON0, RD ; Retrieve word from PFM
MOVF WORD_HIGH_BYTE, W ; Verify high byte
CPFSEQ NVMDATH
BRA NVM_RDERR ; not equal - return error code
MOVF WORD_LOW_BYTE, W ; Verify low byte
CPFSEQ NVMDATL
BRA NVM_RDERR ; not equal - return error code
CLRF WREG,F ; return with no error
BRA NVM_EXIT
NVM_RDERR:
MOVLW 01h
BRA NVM_EXIT
NVM_WRERR:
MOVLW 03h
NVM_EXIT:
BCF NVMCON0, NVMEN ; disable NVM
BSF INTCON, GIE ; re-enable interrupts
RETURN
11.1.4.3 Write Verify
Depending on the application, good programming practice may dictate that the value written to the
memory should be verified against the original value. This should be used in applications where
excessive writes can stress bits near the specification limit. Since program memory is stored as a full
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 165
page, the stored program memory contents are compared with the intended data stored in sector RAM
after the last write is complete.
Figure 11-10. Program Flash Memory Verify Flowchart
Filename: 10-000051B.vsd
Title: FLASH PROGRAM MEMORY VERIFY FLOWCHART
Last Edit: 12/4/2015
First Used: PIC18(L)F2x/4xK40
Note: 1: Refer to Figure 11-5, Program Flash Memory Read Flowchart
Start
Verify Operation
This routine assumes that the last
row of data written was from an
image saved on RAM. This image
will be used to verify the data
currently stored in PFM
Fail
Verify Operation
Last word ?
NVMDAT =
RAM image ?
Read Operation(1)
End
Verify Operation
No
No
Yes
Yes
Rev. 10-000051B
12/4/2015
11.1.4.4 Unexpected Termination of Write Operation
If a write is terminated by an unplanned event, such as loss of power or an unexpected Reset, the
memory location just programmed should be verified and reprogrammed if needed. If the write operation
is interrupted by a MCLR Reset or a WDT Time-out Reset during normal operation, the NVMERR bit will
be set which the user can check to decide whether a rewrite of the location(s) is needed.
11.1.4.5 Protection Against Spurious Writes
A write sequence is valid only when both the following conditions are met. This prevents spurious writes
that might lead to data corruption.
1. The WR, RD, SECWR, SECRD, and SECER bits are gated through the NVMEN bit. It is suggested
to have the NVMEN bit cleared at all times except during memory writes and reads. This prevents
memory operations if any of the control bits are set accidentally.
2. The NVM unlock sequence must be performed each time before all but the RD operation.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 166
11.2 User ID, Device ID and Configuration Word Access
The NVMADR value determines which NVM address space is accessed. The User IDs and Configuration
Words areas allow read and write whereas Device and Revision IDs allow read-only (see NVM
organization table).
Reading and writing User ID space is identical to writing to PFM space as described in the preceding
paragraphs.
Writing to the Configuration space can only be done with the SECWR operation. A sector erase operation
on Configuration space cannot be performed with the SECER operation. When a SECWR operation is
performed on the Configuration space a sector erase is performed automatically before the sector write.
Any code protection settings that are not enabled will remain not enabled after the sector write operation
unless the new values enable them. However, any code protection settings that are enabled cannot be
disabled by a self-write of the Configuration space. The user can modify the Configuration space by the
following steps:
1. Read Configuration space with the unlock and SECRD sequence.
2. Modify the desired Configuration Word holding registers using TBLPTR address, TABLAT data, and
TBLWT* instruction.
3. Write the holding registers to Configuration space with the unlock and SECWR sequence.
Related Links
11. (NVM) Nonvolatile Memory Control
11.3 Data Flash Memory (DFM)
The data Flash memory is a nonvolatile memory array, also referred to as EEPROM. The DFM is
separate from the Program Flash Memory, which is used for long-term storage of program data. The DFM
is mapped above program memory space and is indirectly addressed through the NVM Special Function
Registers (SFRs). The DFM is readable and writable during normal operation over the entire VDD range.
Five SFRs are used to read and write to the data DFM. They are:
NVMCON0
NVMCON1
NVMCON2
NVMDAT
NVMADR
The DFM can only be read and written one byte at a time. When interfacing to the data memory block,
NVMDATL holds the 8-bit data for read/write and the 11.5.5 NVMADR register holds the address of the
DFM location being accessed.
The DFM is rated for high erase/write cycle endurance. A byte write automatically erases the location and
writes the new data (erase-before-write). The write time is controlled by an internal programming timer; it
will vary with voltage and temperature as well as from chip-to-chip. Refer to the data EEPROM memory
parameters in the electrical specifications section for the limits.
Related Links
39.3.5 Memory Programming Specifications
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 167
11.3.1 Reading the DFM
To read a DFM location, the user must write the address to the NVMADR register, enable NVM control by
setting the NVMEN bit, and then set the RD control bit. The data is available on the very next instruction
cycle; therefore, the NVMDAT register can be read by the next instruction. NVMDAT will hold this value
until another read operation, or until it is written to by the user (during a write operation).
The basic process is shown in the following flowchart.
Figure 11-11. DFM Read Flowchart
End Read Operation
Initiate Read Operation
(RD = 1)
Data read now in
NVMDAT
Rev. 30-000009B
5/10/2017
Select Word Address
(NVMADRU:NVMADRH:NVMADRL)
Start Read Operation
Example 11-6. DFM Read
; Data Flash Memory Address to read
BSF NVMCON0, NVMEN ; Enable NVM
MOVF DFM_ADDRL, W ;
MOVWF NVMADRL ; Setup Address low byte
MOVF DFM_ADDRH, W ;
MOVWF NVMADRH ; Setup Address high byte
MOVF DFM_ADDRU, W ;
MOVWF NVMADRU ; Setup Address upper byte
BSF NVMCON1, RD ; Issue EE Read
MOVF NVMDAT, W ; W = EE_DATA
BCF NVMCON0, NVMEN ; Disable NVM
Only byte reads are supported for DFM. Reading a block of DFM with a SECRD operation is not
supported.
11.3.2 Writing to DFM
To write a DFM location, the address must first be written to the NVMADR register and the data written to
the NVMDATL register. The sequence shown in 11.1.2 NVM Unlock Sequence must be followed to
initiate the write cycle. Block writes, also referred to as sector writes, are not supported for the DFM.
The write will not begin if NVM Unlock sequence is not exactly followed for each byte. It is strongly
recommended that interrupts be disabled during this code segment.
Additionally, the NVMEN bit must be set to enable NVM control. This mechanism prevents accidental
writes to DFM due to unexpected code execution (i.e., runaway programs). The NVMEN bit should be
kept clear at all times, except when updating the DFM. The NVMEN bit is not cleared by hardware.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 168
After a write sequence has been initiated, NVMCON1, NVMADR and NVMDAT cannot be modified. The
WR bit will be inhibited from being set unless the NVMEN bit is set.
After a write sequence has been initiated, clearing the NVMEN bit will not affect this write cycle. A single
DFM byte is written and the operation includes an implicit erase cycle for that word. CPU execution
continues in parallel and at the completion of the write cycle, the WR bit is cleared in hardware and the
NVM Interrupt Flag bit (NVMIF) is set. The user can either enable this interrupt or poll this bit. NVMIF
must be cleared by software.
Example 11-7. DFM Write
; Data Flash Memory Address to write
MOVF DFM_ADDRL, W ;
MOVWF NVMADRL ; Setup Address low byte
MOVF DFM_ADDRH, W ;
MOVWF NVMADRH ; Setup Address high byte
MOVF DFM_ADDRU, W ;
MOVWF NVMADRU ; Setup Address upper byte
; Data Memory Value to write
MOVF DMF_DATA, W ;
MOVWF NVMDATL ;
; Enable writes
BSF NVMCON0, NVMEN ; Enable NVM
; Disable interrupts
BCF INTCON, GIE ;
; –------- Required Sequence –--------
MOVLW 55h ;
MOVWF NVMCON2 ;
MOVLW AAh ;
MOVWF NVMCON2 ;
BSF NVMCON1, WR ; Set WR bit to begin write
; –------------------------------------
; Wait for write to complete
BTFSC NVMCON1, WR ; DFM writes do not stall the CPU
BRA $-2
; Enable INT
BSF INTCON, GIE ;
; Disable writes
BCF NVMCON0, NVMEN ;
11.3.3 DFM Write Verify
Depending on the application, good programming practice may dictate that the value written to the
memory should be verified against the original value. This should be used in applications where
excessive writes can stress bits near the specification limit.
11.3.4 Operation During Code-Protect and Write-Protect
DFM has its own code-protect bits in the Configuration Words. In-Circuit Serial Programming read and
write operations are disabled when code protection is enabled. However, internal reads operate normally.
Internal writes operate normally provided that write protection is not enabled.
If the DFM is write-protected or if NVMADR points at an invalid address location, the WR bit is cleared
without any effect. NVMERR is signaled in this scenario.
11.3.5 Protection Against Spurious Write
There are conditions when the user may not want to write to the DFM. To protect against spurious DFM
writes, various mechanisms have been implemented. On any Reset, the NVMEN bit is cleared. In
addition, writes to the DFM are blocked during the Power-up Timer period (TPWRT).
The unlock sequence and the NVMEN bit together help prevent an accidental write during brown-out,
power glitch or software malfunction.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 169
11.3.6 Erasing the DFM
DFM can be erased by writing 0xFF to all locations in the memory that need to be erased.
Example 11-8. DFM Erase Routine
CLRF NVMADRL ; Clear address low byte
CLRF NVMADRH ; Clear address high byte
MOVLW 31h ; EEPROM upper address
MOVWF NVMADRU ; Set address upper byte
SETF NVMDAT ; Load 0xFF to data register
BCF INTCON, GIE ; Disable interrupts
BSF NVMCON0, NVMEN ; Enable NVM
Loop: ; Loop to refresh array
MOVLW 0x55 ; Initiate unlock sequence
MOVWF NVMCON2 ;
MOVLW 0xAA ;
MOVWF NVMCON2 ;
BSF NVMCON1, WR ; Set WR bit to begin write
BTFSC NVMCON1, WR ; Wait for write to complete
BRA $-2
INCFSZ NVMADRL, F ; Increment address low byte
BRA Loop ; Not zero, do it again
; The following 4 lines of code are not needed if EEPROM is 256 bytes or less
INCF NVMADRH, F ; Decrement address high byte
MOVLW 0x03 ; Move 0x03 to working register
CPFSGT NVMADRH ; Compare address high byte with working
register
BRA Loop ; Skip if greater than working register
; Else go back to erase loop
BCF NVMCON0, NVMEN ; Disable NVM
BSF INTCON, GIE ; Enable interrupts
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 170
11.4 Register Summary: NVM Control
Address Name Bit Pos.
0x0F79 NVMADR
7:0 NVMADRL[7:0]
15:8 NVMADRH[7:0]
23:16 NVMADRU[5:0]
0x0F7C NVMDAT
7:0 NVMDATL[7:0]
15:8 NVMDATH[7:0]
0x0F7E Reserved
0x0F7F NVMCON0 7:0 NVMEN NVMERR Reserved
0x0F80 NVMCON1 7:0 SECER SECWR WR SECRD RD
0x0F81 NVMCON2 7:0 NVMCON2[7:0]
0x0F82
...
0x0FF4
Reserved
0x0FF5 TABLAT 7:0 TABLAT[7:0]
0x0FF6 TBLPTR
7:0 TBLPTRL[7:0]
15:8 TBLPTRH[7:0]
23:16 TBLPTR21 TBLPTRU[4:0]
11.5 Register Definitions: Nonvolatile Memory
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 171
11.5.1 NVMCON0
Name:  NVMCON0
Address:  0xF7F
Nonvolatile Memory Control 0 Register
Bit 7 6 5 4 3 2 1 0
NVMEN NVMERR Reserved
Access R/W R/W/HS R/W
Reset 0 x 0
Bit 7 – NVMEN NVM Enable bit
Value Description
1NVM is enabled for all operations
0NVM is disabled for all operations except single byte or word read.
Bit 4 – NVMERR
NVM Error Flag bit
Value Description
1An attempted NVM write or sector read did not complete successfully. Must be cleared by
software.
0All NVM operations have completed successfully.
Bit 3 – Reserved
Reserved - Do not use. This bit must be maintained as ‘0’.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 172
11.5.2 NVMCON1
Name:  NVMCON1
Address:  0xF80
Nonvolatile Memory Control 1 Register
Bit 7 6 5 4 3 2 1 0
SECER SECWR WR SECRD RD
Access R/S/HC R/S/HC R/S/HC R/S/HC R/S/HC
Reset 0 0 0 0 0
Bit 6 – SECER
NVM Sector Erase Enable Control bit
Value Condition Description
1NVMADR points to PFM Immediately following the sector erase unlock sequence, perform a
sector erase operation. Stays set until operation is complete.
Cannot be cleared by software.
0NVMADR points to PFM NVM sector erase operation is complete and inactive.
Bit 5 – SECWR
NVM Sector Write Enable Control bit
Value Condition Description
1NVMADR points to PFM or
CONFIG
Immediately following the sector write unlock sequence,
initiates the PFM sector write operation. Stays set until the
write is complete. Cannot be cleared by software.
0NVMADR points to PFM or
CONFIG
NVM sector write operation is complete and inactive.
Bit 4 – WR
NVM Write Control bit
Value Condition Description
1NVMADR points to
DFM
Immediately following the DFM write unlock sequence, initiates a
DFM byte erase/write sequence using data in the NVMDATL register.
Stays set until the operation is complete. Cannot be cleared by
software.
1NVMADR points to
PFM
Immediately following the PFM write unlock sequence, initiates an
NVM word write sequence using data in the NVMDATH:L register
pair. Stays set until the operation is complete. Cannot be cleared by
software.
0NVMADR points to
PFM or DFM
NVM byte/word write operation is complete and inactive.
Bit 1 – SECRD
PFM Sector Read Enable Control bit
Value Condition Description
1NVMADR points to PFM or
CONFIG
Immediately following the sector read unlock sequence, initiates
a read of one full sector from PFM into sector RAM. Stays set
until the read is complete. Cannot be cleared by software.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 173
Value Condition Description
0NVMADR points to PFM or
CONFIG
PFM sector read operation is complete and inactive.
Bit 0 – RD
NVM Read Enable Control bit
Value Condition Description
1NVMADR points to DFM Initiates a read of one byte from DFM into the NVMDATL register.
Stays set until the read is complete. Cannot be cleared by
software.
1NVMADR points to PFM Initiates a read of one word from PFM into the NVMDATH:L
registers. Stays set until the read is complete. Cannot be cleared
by software.
0NVMADR points to PFM
or DFM
NVM read operation is complete and inactive.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 174
11.5.3 NVMCON2
Name:  NVMCON2
Address:  0xF81
Nonvolatile Memory Control 2 Register
Note:  This register always reads zeros, regardless of data written.
Refer to the NVM Unlock Sequence section
Bit 7 6 5 4 3 2 1 0
NVMCON2[7:0]
Access WO WO WO WO WO WO WO WO
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – NVMCON2[7:0]
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 175
11.5.4 NVMDAT
Name:  NVMDAT
Address:  0xF7C
NVM Data Register
Bit 15 14 13 12 11 10 9 8
NVMDATH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
NVMDATL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – NVMDATH[7:0]
NVMDAT Most Significant Byte of data written to and read from PFM.
Bits 7:0 – NVMDATL[7:0]
NVMDAT Least Significant Byte of data written to and read from PFM or DFM.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 176
11.5.5 NVMADR
Name:  NVMADR
Address:  0xF79
NVM Address Register
Bit 23 22 21 20 19 18 17 16
NVMADRU[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 15 14 13 12 11 10 9 8
NVMADRH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
NVMADRL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 21:16 – NVMADRU[5:0]
NVM address bits <21:16> .
Bits 15:8 – NVMADRH[7:0]
High byte of NVM address.
Bits 7:0 – NVMADRL[7:0]
Low byte of NVM address.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 177
11.5.6 TABLAT
Name:  TABLAT
Address:  0xFF5
Program, Configuration, Device ID, and User ID Memory Data
Bit 7 6 5 4 3 2 1 0
TABLAT[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – TABLAT[7:0] The value of the NVM memory byte returned from the address contained in
TBLPTR after a TBLRD command, or the data written to the latch by a TBLWT command.
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 178
11.5.7 TBLPTR
Name:  TBLPTR
Address:  0xFF6
Program, Configuration, Device ID and User ID Memory Address
Bit 23 22 21 20 19 18 17 16
TBLPTR21 TBLPTRU[4:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 15 14 13 12 11 10 9 8
TBLPTRH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
TBLPTRL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 21 – TBLPTR21 NVM Most Significant Address bit
Value Description
1Access Configuration, User ID, Device ID, and Revision ID spaces
0Access Program Flash Memory space
Bits 20:16 – TBLPTRU[4:0] NVM Upper Address bits
Bits 15:8 – TBLPTRH[7:0] High Byte of NVM Address bits
Bits 7:0 – TBLPTRL[7:0] Low Byte of NVM Address bits
PIC18F26/45/46Q10
(NVM) Nonvolatile Memory Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 179
12. 8x8 Hardware Multiplier
12.1 Introduction
All PIC18 devices include an 8x8 hardware multiplier as part of the ALU. The multiplier performs an
unsigned operation and yields a 16-bit result that is stored in the product register pair, PRODH:PRODL.
The multiplier’s operation does not affect any flags in the STATUS register.
Making multiplication a hardware operation allows it to be completed in a single instruction cycle. This
has the advantages of higher computational throughput and reduced code size for multiplication
algorithms and allows the PIC18 devices to be used in many applications previously reserved for digital
signal processors. A comparison of various hardware and software multiply operations, along with the
savings in memory and execution time, is shown in Table 12-1.
12.2 Operation
Example 12-1 shows the instruction sequence for an 8x8 unsigned multiplication. Only one instruction is
required when one of the arguments is already loaded in the WREG register.
Example 12-2 shows the sequence to do an 8x8 signed multiplication. To account for the sign bits of the
arguments, each argument’s Most Significant bit (MSb) is tested and the appropriate subtractions are
done.
Example 12-1. 8x8 Unsigned Multiply Routine
MOVF ARG1, W ;
MULWF ARG2 ; ARG1 * ARG2 -> PRODH:PRODL
Example 12-2. 8x8 Signed Multiply Routine
MOVF ARG1, W
MULWF ARG2 ; ARG1 * ARG2 -> PRODH:PRODL
BTFSC ARG2, SB ; Test Sign Bit
SUBWF PRODH, F ; PRODH = PRODH - ARG1
MOVF ARG2, W
BTFSC ARG1, SB ; Test Sign Bit
SUBWF PRODH, F ; PRODH = PRODH - ARG2
Table 12-1. Performance Comparison for Various Multiply Operations
Routine Multiply Method
Program
Memory
(Words)
Cycles
(Max)
Time
@ 64 MHz @ 40 MHz @ 10 MHz @ 4 MHz
8x8 unsigned
Without hardware
multiply
13 69 4.3 μs 6.9 μs 27.6 μs 69 μs
Hardware multiply 1 1 62.5 ns 100 ns 400 ns 1 μs
PIC18F26/45/46Q10
8x8 Hardware Multiplier
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 180
...........continued
Routine Multiply Method
Program
Memory
(Words)
Cycles
(Max)
Time
@ 64 MHz @ 40 MHz @ 10 MHz @ 4 MHz
8x8 signed
Without hardware
multiply
33 91 5.7 μs 9.1 μs 36.4 μs 91 μs
Hardware multiply 6 6 375 ns 600 ns 2.4 μs 6 μs
16x16 unsigned
Without hardware
multiply
21 242 15.1 μs 24.2 μs 96.8 μs 242 μs
Hardware multiply 28 28 1.8 μs 2.8 μs 11.2 μs 28 μs
16x16 signed
Without hardware
multiply
52 254 15.9 μs 25.4 μs 102.6 μs 254 μs
Hardware multiply 35 40 2.5 μs 4.0 μs 16.0 μs 40 μs
Example 12-3 shows the sequence to do a 16 x 16 unsigned multiplication. The equation below shows
the algorithm that is used. The 32-bit result is stored in four registers (RES<3:0>).
16 x 16 Unsigned Multiplication Algorithm
3:0 = 1:12:2=12 216 +12 28+
12 28+12
Example 12-3. 16 x 16 Unsigned Multiply Routine
MOVF ARG1L, W
MULWF ARG2L ; ARG1L * ARG2L → PRODH:PRODL
MOVFF PRODH, RES1 ;
MOVFF PRODL, RES0 ;
;
MOVF ARG1H, W ;
MULWF ARG2H ; ARG1H * ARG2H → PRODH:PRODL
MOVFF PRODH, RES3 ;
MOVFF PRODL, RES2 ;
;
MOVF ARG1L, W
MULWF ARG2H ; ARG1L * ARG2H → PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross products
MOVF PRODH, W ;
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
MOVF ARG1H, W ;
MULWF ARG2L ; ARG1H * ARG2L → PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross products
MOVF PRODH, W ;
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
Example 12-4 shows the sequence to do a 16 x 16 signed multiply. The equation below shows the
algorithm used. The 32-bit result is stored in four registers (RES<3:0>). To account for the sign bits of the
arguments, the MSb for each argument pair is tested and the appropriate subtractions are done.
PIC18F26/45/46Q10
8x8 Hardware Multiplier
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 181
16 x 16 Signed Multiplication Algorithm
3:0 = 1:12:2=12 216 +12 28+
12 28+12+1 2< 7 > 1:1 216 +1
1< 7 > 2:2 216
Example 12-4. 16 x 16 Signed Multiply Routine
MOVF ARG1L, W
MULW ARG2L ; ARG1L * ARG2L → PRODH:PRODL
MOVF PRODH, RES1 ;
MOVFF PRODL, RES0 ;
;
MOVF ARG1H, W
MULWF ARG2H ; ARG1H * ARG2H → PRODH:PRODL
MOVFF PRODH, RES3 ;
MOVFF PRODL, RES2 ;
;
MOVF ARG1L, W
MULWF ARG2H ; ARG1L * ARG2H → PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross products
MOVF PRODH, W ;
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
MOVF ARG1H, W ;
MULWF ARG2L ; ARG1H * ARG2L → PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross products
MOVF PRODH, W ;
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
BTFSS ARG2H, 7 ; ARG2H:ARG2L neg?
BRA SIGN_ARG1 ; no, check ARG1
MOVF ARG1L, W ;
SUBWF RES2 ;
MOVF ARG1H, W ;
SUBWFB RES3
;
SIGN_ARG1:
BTFSS ARG1H, 7 ; ARG1H:ARG1L neg?
BRA CONT_CODE ; no, done
MOVF ARG2L, W ;
SUBWF RES2 ;
MOVF ARG2H, W ;
SUBWFB RES3
;
CONT_CODE:
:
PIC18F26/45/46Q10
8x8 Hardware Multiplier
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 182
12.3 Register Summary - 8x8 Hardware Multiplier
Address Name Bit Pos.
0x0FF3 PROD
7:0 PRODL[7:0]
15:8 PRODH[7:0]
12.4 Register Definitions: 8x8 Hardware Multiplier
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12.4.1 PROD
Name:  PROD
Address:  0xFF3
Product Register Pair
The PROD register stores the 16-bit result yielded by the unsigned operation performed by the 8x8
hardware multiplier.
Bit 15 14 13 12 11 10 9 8
PRODH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
PRODL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 15:8 – PRODH[7:0]
PROD Most Significant bits
Bits 7:0 – PRODL[7:0]
PROD Least Significant bits
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13. (CRC) Cyclic Redundancy Check Module with Memory Scanner
The Cyclic Redundancy Check (CRC) module provides a software-configurable hardware-implemented
CRC checksum generator. This module includes the following features:
Any standard CRC up to 16 bits can be used
Configurable Polynomial
Any seed value up to 16 bits can be used
Standard and reversed bit order available
Augmented zeros can be added automatically or by the user
Memory scanner for fast CRC calculations on program memory user data
Software loadable data registers for communication CRC’s
13.1 CRC Module Overview
The CRC module provides a means for calculating a check value of program memory. The CRC module
is coupled with a memory scanner for faster CRC calculations. The memory scanner can automatically
provide data to the CRC module. The CRC module can also be operated by directly writing data to SFRs,
without using a scanner.
13.2 CRC Functional Overview
The CRC module can be used to detect bit errors in the Flash memory using the built-in memory scanner
or through user input RAM memory. The CRC module can accept up to a 16-bit polynomial with up to a
16-bit seed value. A CRC calculated check value (or checksum) will then be generated into the 13.12.4
CRCACC registers for user storage. The CRC module uses an XOR shift register implementation to
perform the polynomial division required for the CRC calculation.
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Figure 13-1. CRC Example
Filename: 10-000206A.vsd
Title: CRC EXAMPLE
Last Edit: 1/8/2014
First Used: PIC16(L)F1613
Notes:
Rev. 10-000206A
1/8/2014
CRC-16-ANSI
x16 + x15 + x2+ 1 (17 bits)
CRCXORH = 0b10000000
CRCXORL = 0b0000010- (1)
Standard 16-bit representation = 0x8005
Data Sequence:
0x55, 0x66, 0x77, 0x88
Check Value (ACCM = 1):
SHIFTM = 0: 0x32D6
CRCACCH = 0b00110010
CRCACCL = 0b11010110
SHIFTM = 1: 0x6BA2
CRCACCH = 0b01101011
CRCACCL = 0b10100010
DLEN = 0b0111
PLEN = 0b1111
Data entered into the CRC:
SHIFTM = 0:
01010101 01100110 01110111 10001000
SHIFTM = 1:
10101010 01100110 11101110 00010001
Note 1: Bit 0 is unimplemented. The LSb of any
CRC polynomial is always ‘1’ and will always
be treated as a ‘1’ by the CRC for calculating
the CRC check value. This bit will be read in
software as a ‘0’.
13.3 CRC Polynomial Implementation
Any polynomial can be used. The polynomial and accumulator sizes are determined by the PLEN bits.
For an n-bit accumulator, PLEN = n-1 and the corresponding polynomial is n+1 bits. Therefore, the
accumulator can be any size up to 16 bits with a corresponding polynomial up to 17 bits. The MSb and
LSb of the polynomial are always ‘1’ which is forced by hardware. However, the LSb of the CRCXORL
register is unimplemented and always reads as '0'.
All polynomial bits between the MSb and LSb are specified by the 13.12.6 CRCXOR registers. For
example, when using CRC16-ANSI, the polynomial is defined as X16+X15+X2+1. The X16 and X0 = 1
terms are the MSb and LSb controlled by hardware. The X15 and X2 terms are specified by setting the
corresponding CRCXOR<15:0> bits with the value of 0x8004. The actual value is 0x8005 because the
hardware sets the LSb to 1. Refer to Figure 13-1.
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Figure 13-2. CRC LFSR Example
Filename: 10-000207A.vsd
Title: CRC LFSR EXAMPLE
Last Edit: 5/27/2014
First Used: PIC16F1613 LECQ
Notes:
Rev. 10-000207A
5/27/2014
Data in
b0b1b2b3b4b5b6b7b8b9b10b11b12b13b14b15
Linear Feedback Shift Register for CRC-16-ANSI
x16 + x15 + x2+ 1
b0b1b2b3b4b5b6b7b8b9b10b11b12b13b14b15
Data in
Augmentation Mode OFF
Augmentation Mode ON
13.4 CRC Data Sources
Data can be input to the CRC module in two ways:
User data using the 13.12.3 CRCDAT registers
From Flash memory using the program memory scanner
Up to 16 bits of data per word are specified with the DLEN bits. Only the number of data bits in the
CRCDATA registers specified by DLEN will be used, other data bits in CRCDATA registers will be
ignored.
Data is moved into the 13.12.5 CRCSHIFT as an intermediate to calculate the check value located in the
13.12.4 CRCACC registers.
The SHIFTM bit is used to determine the bit order of the data being shifted into the accumulator. If
SHIFTM is not set, the data will be shifted in MSb first (Big Endian). The value of DLEN will determine the
MSb. If SHIFTM bit is set, the data will be shifted into the accumulator in reversed order, LSb first (Little
Endian).
The CRC module can be seeded with an initial value by setting the CRCACC registers to the appropriate
value before beginning the CRC.
13.4.1 CRC from User Data
To use the CRC module on data input from the user, the user must write the data to the CRCDAT
registers. The data from the CRCDAT registers will be latched into the shift registers on any write to the
CRCDATL register.
13.4.2 CRC from Flash
To use the CRC module on data located in Flash memory, the user can initialize the program memory
scanner as defined in the 13.8 Program Memory Scan Configuration section.
13.5 CRC Check Value
The CRC check value will be located in the CRCACC registers after the CRC calculation has finished.
The check value will depend on the ACCM and SHIFTM mode settings.
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When the ACCM bit is set, the CRC module augments the data with a number of zeros equal to the
length of the polynomial to align the final check value. When the ACCM bit is not set, the CRC will stop at
the end of the data. A number of zeros equal to the length of the polynomial can then be entered into
CRCDAT to find the same check value as augmented mode. Alternatively, the expected check value can
be entered at this point to make the final result equal 0.
When the CRC check value is computed with the SHIFTM bit set, selecting LSb first, and the ACCM bit is
set then the final value in the CRCACC registers will be reversed such that the LSb will be in the MSb
position and vice versa. This is the expected check value in bit reversed form. When creating a check
value to be appended to a data stream, then a bit reversal must be performed on the final value to
achieve the correct checksum. CRC can be used to do this reversal by following the steps below:
1. Save CRCACC value in user RAM space
2. Clear the CRCACC registers
3. Clear the CRCXOR registers
4. Write the saved CRCACC value to the CRCDAT input
The properly oriented check value will be in the CRCACC registers as the result.
13.6 CRC Interrupt
The CRC will generate an interrupt when the BUSY bit transitions from 1 to 0. The CRCIF Interrupt Flag
bit of the PIRx register is set every time the BUSY bit transitions, regardless of whether or not the CRC
interrupt is enabled. The CRCIF bit can only be cleared in software. The CRC interrupt enable is the
CRCIE bit of the PIEx register.
13.7 Configuring the CRC
The following steps illustrate how to properly configure the CRC.
1. Determine if the automatic program memory scan will be used with the scanner or manual
calculation through the SFR interface and perform the actions specified in 13.4 CRC Data
Sources, depending on which decision was made.
2. If desired, seed a starting CRC value into the 13.12.4 CRCACC registers.
3. Program the 13.12.6 CRCXOR registers with the desired generator polynomial.
4. Program the DLENbits with the length of the data word - 1 (refer to Figure 13-1). This determines
how many times the shifter will shift into the accumulator for each data word.
5. Program the PLEN bits with the length of the polynomial -2 (refer to Figure 13-1).
6. Determine whether shifting in trailing zeros is desired and set the ACCM bit accordingly.
7. Likewise, determine whether the MSb or LSb should be shifted first and write the SHIFTM bit
accordingly.
8. Set the GO bit to begin the shifting process.
9. If manual SFR entry is used, monitor the FULL bit. When FULL = 0, another word of data can be
written to the 13.12.3 CRCDAT registers, keeping in mind that Most Significant Byte, CRCDATH,
should be written first if the data has more than eight bits, as the shifter will begin upon the
CRCDATL register being written.
10. If the scanner is used, the scanner will automatically stuff words into the CRCDAT registers as
needed, as long as the SCANGO bit is set.
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11. If using the Flash memory scanner, monitor the PIRx SCANIF bit (or the SCANGO bit) for the
scanner to finish pushing information into the CRCDATA registers. After the scanner is completed,
monitor the BUSY bit to determine that the CRC has been completed and the check value can be
read from the CRCACC registers. If both the interrupt flags are set (or both BUSY and SCANGO
bits are cleared), the completed CRC calculation can be read from the CRCACC registers.
12. If manual entry is used, monitor the BUSY bit to determine when the CRCACC registers hold the
valid check value.
13.8 Program Memory Scan Configuration
The program memory scan module may be used in conjunction with the CRC module to perform a CRC
calculation over a range of program memory addresses. In order to setup the scanner to work with the
CRC the following steps need to performed:
1. Set both the EN and SCANEN bits. If they get disabled, all internal states of the scanner and the
CRC are reset. However, the CRC SFR registers are unaffected.
2. Choose which memory access mode is to be used (see 13.10 Scanning Modes) and set the
MODE bits accordingly.
3. Based on the memory access mode, set the INTM bits to the appropriate Interrupt mode (see
13.10.5 Interrupt Interaction)
4. Set the 13.12.8 SCANLADR and 13.12.9 SCANHADR registers with the respective beginning and
ending locations in memory that are to be scanned.
5. The GO bit must be set before setting the SCANGO bit. Setting the SCANGO bit starts the scan.
Both the EN and GO bits must be enabled to use the scanner. When either of these bits are
disabled, the scan aborts and the INVALID bit is set. The scanner will wait for the signal from the
CRC that it is ready for the first Flash memory location, then begin loading data into the CRC. It will
continue to do so until it either hits the configured end address or an address that is unimplemented
on the device, at which point the SCANGO bit will clear, Scanner functions will cease, and the
SCANIF interrupt will be triggered. Alternately, the SCANGO bit can be cleared in software to
terminate the scan early if desired.
13.9 Scanner Interrupt
The scanner will trigger an interrupt when the SCANGO bit transitions from ‘1’ to ‘0’. The SCANIF
interrupt flag of PIRx is set when the last memory location is reached and the data is entered into the
CRCDATA registers. The SCANIF bit can only be cleared in software. The SCAN interrupt enable is the
SCANIE bit of the PIEx register.
13.10 Scanning Modes
The memory scanner can scan in four modes: Burst, Peek, Concurrent, and Triggered. These modes are
controlled by the MODE bits. The four modes are summarized in Table 13-1.
13.10.1 Burst Mode
When MODE = 01, the scanner is in Burst mode. In Burst mode, CPU operation is stalled beginning with
the operation after the one that sets the SCANGO bit, and the scan begins, using the instruction clock to
execute. The CPU is held in its current state until the scan stops. Note that because the CPU is not
executing instructions, the SCANGO bit cannot be cleared in software, so the CPU will remain stalled
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until one of the hardware end-conditions occurs. Burst mode has the highest throughput for the scanner,
but has the cost of stalling other execution while it occurs.
13.10.2 Concurrent Mode
When MODE = 00, the scanner is in Concurrent mode. Concurrent mode, like Burst mode, stalls the CPU
while performing accesses of memory. However, while Burst mode stalls until all accesses are complete,
Concurrent mode allows the CPU to execute in between access cycles.
13.10.3 Triggered mode
When MODE = 11, the scanner is in Triggered mode. Triggered mode behaves identically to Concurrent
mode, except instead of beginning the scan immediately upon the SCANGO bit being set, it waits for a
rising edge from a separate trigger source which is determined by the 13.12.10 SCANTRIG register.
13.10.4 Peek Mode
When MODE = 10, the scanner is in Peek mode. Peek mode waits for an instruction cycle in which the
CPU does not need to access the NVM (such as a branch instruction) and uses that cycle to do its own
NVM access. This results in the lowest throughput for the NVM access (and can take a much longer time
to complete a scan than the other modes), but does so without any impact on execution times, unlike the
other modes.
Table 13-1. Summary of Scanner Modes
MODE<1:0>
Description
First Scan Access CPU Operation
11 Triggered As soon as possible
following a trigger
Stalled during NVM
access
CPU resumes execution
following each access
10 Peek At the first dead cycle Timing is unaffected CPU continues execution
following each access
01 Burst
As soon as possible Stalled during NVM
access
CPU suspended until scan
completes
00 Concurrent CPU resumes execution
following each access
13.10.5 Interrupt Interaction
The INTM bit controls the scanner’s response to interrupts depending on which mode the NVM scanner is
in, as described in the following table.
Table 13-2. Scan Interrupt Modes
INTM
MODE<1:0>
MODE == Burst MODE == CONCURENT or
TRIGGERED MODE ==PEEK
1
Interrupt overrides SCANGO (to zero) to
pause the burst and the interrupt handler
executes at full speed; Scanner Burst
resumes when interrupt completes.
Scanner suspended during
interrupt response (SCANGO = 0);
interrupt executes at full speed and
scan resumes when the interrupt is
complete.
This bit is
ignored
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...........continued
INTM
MODE<1:0>
MODE == Burst MODE == CONCURENT or
TRIGGERED MODE ==PEEK
0
Interrupts do not override SCANGO, and
the scan (burst) operation will continue;
interrupt response will be delayed until
scan completes (latency will be
increased).
Scanner accesses NVM during
interrupt response.
This bit is
ignored
In general, if INTM = 0, the scanner will take precedence over the interrupt, resulting in decreased
interrupt processing speed and/or increased interrupt response latency. If INTM = 1, the interrupt will take
precedence and have a better speed, delaying the memory scan.
13.10.6 WWDT interaction
Operation of the WWDT is not affected by scanner activity. Hence, it is possible that long scans,
particularly in Burst mode, may exceed the WWDT time-out period and result in an undesired device
Reset. This should be considered when performing memory scans with an application that also utilizes
WWDT.
13.10.7 In-Circuit Debug (ICD) Interaction
The scanner freezes when an ICD halt occurs, and remains frozen until user-mode operation resumes.
The debugger may inspect the SCANCON0 and SCANLADR registers to determine the state of the scan.
The ICD interaction with each operating mode is summarized in the following table.
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Table 13-3. ICD and Scanner Interactions
ICD Halt
Scanner Operating Mode
Peek Concurrent
Triggered Burst
External
Halt
If scanner would peek
an instruction that is
not executed (because
of ICD entry), the peek
will occur after ICD
exit, when the
instruction executes.
If external halt is
asserted during a scan
cycle, the instruction
(delayed by scan) may
or may not execute
before ICD entry,
depending on external
halt timing.
If external halt is asserted during the
BSF(SCANCON.GO), ICD entry
occurs, and the burst is delayed until
ICD exit.
Otherwise, the current NVM-access
cycle will complete, and then the
scanner will be interrupted for ICD
entry.
If external halt is
asserted during the
cycle immediately prior
to the scan cycle, both
scan and instruction
execution happen after
the ICD exits.
If external halt is asserted during the
burst, the burst is suspended and will
resume with ICD exit.
PC
Breakpoint
Scan cycle occurs
before ICD entry and
instruction execution
happens after the ICD
exits.
If PCPB (or single step) is on
BSF(SCANCON.GO), the ICD is
entered before execution; execution of
the burst will occur at ICD exit, and the
burst will run to completion.
Note that the burst can be interrupted
by an external halt.
Data
Breakpoint
The instruction with the
dataBP executes and
ICD entry occurs
immediately after. If
scan is requested
during that cycle, the
scan cycle is
postponed until the ICD
exits.
Single Step
If a scan cycle is ready
after the debug
instruction is executed,
the scan will read PFM
and then the ICD is re-
entered.
SWBP and
ICDINST
If scan would stall a
SWBP, the scan cycle
occurs and the ICD is
entered.
If SWBP replaces
BSF(SCANCON.GO), the ICD will be
entered; instruction execution will occur
at ICD exit (from ICDINSTR register),
and the burst will run to completion.
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13.10.8 Peripheral Module Disable
Both the CRC and scanner module can be disabled individually by setting the CRCMD and SCANMD bits
of the PMD0 register. The SCANMD can be used to enable or disable to the scanner module only if the
SCANE bit of Configuration Word 4 is set. If the SCANE bit is cleared, then the scanner module is not
available for use and the SCANMD bit is ignored.
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13.11 Register Summary - CRC
Address Name Bit Pos.
0x0F44 SCANLADR
7:0 SCANLADRL[7:0]
15:8 SCANLADRH[7:0]
23:16 SCANLADRU[5:0]
0x0F47 SCANHADR
7:0 SCANHADRL[7:0]
15:8 SCANHADRH[7:0]
23:16 SCANHADRU[5:0]
0x0F4A SCANCON0 7:0 SCANEN SCANGO BUSY INVALID INTM MODE[1:0]
0x0F4B SCANTRIG 7:0 TSEL[4:0]
0x0F4C
...
0x0F6E
Reserved
0x0F6F CRCDAT
7:0 CRCDATL[7:0]
15:8 CRCDATH[7:0]
0x0F71 CRCACC
7:0 CRCACCL[7:0]
15:8 CRCACCH[7:0]
0x0F73 CRCSHIFT
7:0 CRCSHIFTL[7:0]
15:8 CRCSHIFTH[7:0]
0x0F75 CRCXOR
7:0 CRCXORL[6:0] CRCXORL0
15:8 CRCXORH[7:0]
0x0F77 CRCCON0 7:0 EN GO BUSY ACCM SHIFTM FULL
0x0F78 CRCCON1 7:0 DLEN[3:0] PLEN[3:0]
13.12 Register Definitions: CRC and Scanner Control
Long bit name prefixes for the CRC are shown in the table below. Refer to the "Long Bit Names Section"
for more information.
Table 13-4. CRC Long Bit Name Prefixes
Peripheral Bit Name Prefix
CRC CRC
Related Links
1.4.2.2 Long Bit Names
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13.12.1 CRCCON0
Name:  CRCCON0
Address:  0xF77
Reset:  0
CRC Control Register 0
Bit 7 6 5 4 3 2 1 0
EN GO BUSY ACCM SHIFTM FULL
Access R/W R/W RO R/W R/W RO
Reset 0 0 0 0 0 0
Bit 7 – EN CRC Enable bit
Value Description
1CRC module is released from Reset
0CRC is disabled and consumes no operating current
Bit 6 – GO CRC Start bit
Value Description
1Start CRC serial shifter
0CRC serial shifter turned off
Bit 5 – BUSY CRC Busy bit
Value Description
1Shifting in progress or pending
0All valid bits in shifter have been shifted into accumulator and EMPTY = 1
Bit 4 – ACCM Accumulator Mode bit
Value Description
1Data is augmented with zeros
0Data is not augmented with zeros
Bit 1 – SHIFTM Shift Mode bit
Value Description
1Shift right (LSb)
0Shift left (MSb)
Bit 0 – FULL Data Path Full Indicator bit
Value Description
1CRCDATH/L registers are full
0CRCDATH/L registers have shifted their data into the shifter
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13.12.2 CRCCON1
Name:  CRCCON1
Address:  0xF78
Reset:  0
CRC Control Register 1
Bit 7 6 5 4 3 2 1 0
DLEN[3:0] PLEN[3:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:4 – DLEN[3:0] Data Length bits
Denotes the length of the data word -1 (See Figure 13-1)
Bits 3:0 – PLEN[3:0] Polynomial Length bits
Denotes the length of the polynomial -1 (See Figure 13-1)
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13.12.3 CRCDAT
Name:  CRCDAT
Address:  0xF6F
CRC Data Register
Bit 15 14 13 12 11 10 9 8
CRCDATH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
CRCDATL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 15:8 – CRCDATH[7:0] CRC Input/Output Data Most Significant Byte
Bits 7:0 – CRCDATL[7:0] CRC Input/Output Data Least Significant Byte
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13.12.4 CRCACC
Name:  CRCACC
Address:  0xF71
Reset:  0
CRC Accumulator Register
Bit 15 14 13 12 11 10 9 8
CRCACCH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
CRCACCL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – CRCACCH[7:0] CRC Accumulator Register most significant byte
Writing to this register writes the Most Significant Byte of the CRC accumulator register. Reading from
this register reads the Most Significant Byte of the CRC accumulator.
Bits 7:0 – CRCACCL[7:0] CRC Accumulator Register least significant byte
Writing to this register writes the Least Significant Byte of the CRC accumulator register. Reading from
this register reads the Least Significant Byte of the CRC accumulator.
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13.12.5 CRCSHIFT
Name:  CRCSHIFT
Address:  0xF73
Reset:  0
CRC Shift Register
Bit 15 14 13 12 11 10 9 8
CRCSHIFTH[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
CRCSHIFTL[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – CRCSHIFTH[7:0] CRC Shifter Register Most Significant Byte
Reading from this register reads the Most Significant Byte of the CRC Shifter.
Bits 7:0 – CRCSHIFTL[7:0] CRC Shifter Register Least Significant Byte
Reading from this register reads the Least Significant Byte of the CRC Shifter.
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13.12.6 CRCXOR
Name:  CRCXOR
Address:  0xF75
CRC XOR Register
Bit 15 14 13 12 11 10 9 8
CRCXORH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
CRCXORL[6:0] CRCXORL0
Access R/W R/W R/W R/W R/W R/W R/W U
Reset x x x x x x x 1
Bits 15:8 – CRCXORH[7:0] XOR of Polynomial Term XN Enable Most Significant Byte
Bits 7:1 – CRCXORL[6:0] XOR of Polynomial Term XN Enable Least Significant Byte
Bit 0 – CRCXORL0 LSbit is unimplemented. Read as 1
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13.12.7 SCANCON0
Name:  SCANCON0
Address:  0xF4A
Scanner Access Control Register 0
Bit 7 6 5 4 3 2 1 0
SCANEN SCANGO BUSY INVALID INTM MODE[1:0]
Access R/W R/W/HC R R R/W R/W R/W
Reset 0 0 0 1 0 0 0
Bit 7 – SCANEN  Scanner Enable bit(1)
Value Description
1Scanner is enabled
0Scanner is disabled, internal states are reset
Bit 6 – SCANGO  Scanner GO bit(2, 3)
Value Description
1When the CRC sends a ready signal, NVM will be accessed according to MDx and data
passed to the client peripheral.
0Scanner operations will not occur
Bit 5 – BUSY  Scanner Busy Indicator bit(4)
Value Description
1Scanner cycle is in process
0Scanner cycle is complete (or never started)
Bit 4 – INVALID Scanner Abort Signal bit
Value Description
1SCANLADRL/H/U has incremented to an invalid address(6) or the scanner was not setup
correctly(7)
0SCANLADRL/H/U points to a valid address
Bit 3 – INTM NVM Scanner Interrupt Management Mode Select bit
Value Condition Description
XMODE = 10 This bit is ignored
1MODE = 01 CPU is stalled until all data is transferred. SCANGO is overridden (to
zero) during interrupt operation; scanner resumes after returning from
interrupt
0MODE = 01 CPU is stalled until all data is transferred. SCANGO is not affected by
interrupts, the interrupt response will be affected
1MODE = 00 OR 11 SCANGO is overridden (to zero) during interrupt operation; scan
operations resume after returning from interrupt
0MODE = 00 OR 11 Interrupts do not prevent NVM access
Bits 1:0 – MODE[1:0]  Memory Access Mode bits(5)
Value Description
11 Triggered mode
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Value Description
10 Peek mode
01 Burst mode
00 Concurrent mode
Note: 
1. Setting SCANEN = 0 (SCANCON0 register) does not affect any other register content.
2. This bit is cleared when LADR > HADR (and a data cycle is not occurring).
3. If INTM = 1, this bit is overridden (to zero, but not cleared) during an interrupt response.
4. BUSY = 1 when the NVM is being accessed, or when the CRC sends a ready signal.
5. See Table 13-1 for more detailed information.
6. An invalid address can occur when the entire range of PFM is scanned and the value of LADR rolls
over. An invalid address can also occur if the value in the Scan Low address registers points to a
location that is not mapped in the memory map of the device.
7. CRCEN and CRCGO bits must be set before setting SCANGO bit. Refer to 13.8 Program Memory
Scan Configuration.
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13.12.8 SCANLADR
Name:  SCANLADR
Address:  0xF44
Reset:  0
Scan Low Address Register
Bit 23 22 21 20 19 18 17 16
SCANLADRU[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 15 14 13 12 11 10 9 8
SCANLADRH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
SCANLADRL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 21:16 – SCANLADRU[5:0] Scan Start/Current Address upper byte
Upper bits of the current address to be fetched from, value increments on each fetch of memory.
Bits 15:8 – SCANLADRH[7:0] Scan Start/Current Address high byte
High byte of the current address to be fetched from, value increments on each fetch of memory.
Bits 7:0 – SCANLADRL[7:0] Scan Start/Current Address low byte
Low byte of the current address to be fetched from, value increments on each fetch of memory.
Note: 
1. Registers SCANLADRU/H/L form a 22-bit value, but are not guarded for atomic or asynchronous
access; registers should only be read or written while SCANGO = 0.
2. While SCANGO = 1, writing to this register is ignored.
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13.12.9 SCANHADR
Name:  SCANHADR
Address:  0xF47
Reset:  0
Scan High Address Register
Bit 23 22 21 20 19 18 17 16
SCANHADRU[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1
Bit 15 14 13 12 11 10 9 8
SCANHADRH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bit 7 6 5 4 3 2 1 0
SCANHADRL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 21:16 – SCANHADRU[5:0] Scan End Address bits
Upper bits of the address at the end of the designated scan
Bits 15:8 – SCANHADRH[7:0] Scan End Address bits
High byte of the address at the end of the designated scan
Bits 7:0 – SCANHADRL[7:0] Scan End Address bits
Low byte of the address at the end of the designated scan
Note: 
1. Registers SCANHADRU/H/L form a 22-bit value but are not guarded for atomic or asynchronous
access; registers should only be read or written while SCANGO = 0.
2. While SCANGO = 1, writing to this register is ignored.
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13.12.10 SCANTRIG
Name:  SCANTRIG
Address:  0xF4B
Reset:  0
SCAN Trigger Selection Register
Bit 7 6 5 4 3 2 1 0
TSEL[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – TSEL[4:0] Scanner Data Trigger Input Selection bits
Table 13-5. SCAN Trigger Sources
TSEL Trigger Source
11000 - 11111 Reserved
10111 CLC8_out
10110 CLC7_out
10101 CLC6_out
10100 CLC5_out
10011 CLC4_out
10010 CLC3_out
10001 CLC2_out
10000 CLC1_out
01001 - 01111 Reserved
01000 TMR6_postscaled
00111 TMR5_output
00110 TMR4_postscaled
00101 TMR3_output
00100 TMR2_postscaled
00011 TMR1_output
00010 TMR0_output
00001 CLKREF_output
00000 LFINTOSC
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14. Interrupts
The PIC18F26/45/46Q10 devices have multiple interrupt sources and an interrupt priority feature that
allows most interrupt sources to be assigned a high or low-priority level. The high-priority interrupt vector
is at 0008h and the low-priority interrupt vector is at 0018h. A high-priority interrupt event will interrupt a
low-priority interrupt that may be in progress.
The registers for controlling interrupt operation are:
INTCON
PIRx (Interrupt flags)
PIEx (Interrupt enables)
IPRx (High/Low interrupt priority)
It is recommended that the Microchip header files supplied with MPLAB® IDE be used for the symbolic bit
names in these registers. This allows the assembler/compiler to automatically take care of the placement
of these bits within the specified register.
In general, interrupt sources have three bits to control their operation. They are:
Flag bit to indicate that an interrupt event occurred
Enable bit that allows program execution to branch to the interrupt vector address when the flag bit
is set
Priority bit to select high priority or low priority
14.1 Midrange Compatibility
When the IPEN bit is cleared (default state), the interrupt priority feature is disabled and interrupts are
compatible with PIC® microcontroller midrange devices. In Compatibility mode, the interrupt priority bits of
the IPRx registers have no effect. The PEIE/GIEL bit is the global interrupt enable for the peripherals. The
PEIE/GIEL bit disables only the peripheral interrupt sources and enables the peripheral interrupt sources
when the GIE/GIEH bit is also set. The GIE/GIEH bit is the global interrupt enable which enables all non-
peripheral interrupt sources and disables all interrupt sources, including the peripherals. All interrupts
branch to address 0008h in Compatibility mode.
14.2 Interrupt Priority
The interrupt priority feature is enabled by setting the IPEN bit. When interrupt priority is enabled the GIE/
GIEH and PEIE/GIEL Global Interrupt Enable bits of Compatibility mode are replaced by the GIEH high
priority, and GIEL low priority, global interrupt enables. When the IPEN bit is set, the GIEH bit enables all
interrupts which have their associated bit in the IPRx register set. When the GIEH bit is cleared, then all
interrupt sources including those selected as low priority in the IPRx register are disabled.
When both GIEH and GIEL bits are set, all interrupts selected as low priority sources are enabled.
A high-priority interrupt will vector immediately to address 00 0008h and a low-priority interrupt will vector
to address 00 0018h.
14.3 Interrupt Response
When an interrupt is responded to, the Global Interrupt Enable bit is cleared to disable further interrupts.
The GIE/GIEH bit is the Global Interrupt Enable when the IPEN bit is cleared. When the IPEN bit is set,
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enabling interrupt priority levels, the GIEH bit is the high priority Global Interrupt Enable and the GIEL bit
is the low priority Global Interrupt Enable. High-priority interrupt sources can interrupt a low-priority
interrupt. Low-priority interrupts are not processed while high-priority interrupts are in progress.
The return address is pushed onto the stack and the PC is loaded with the interrupt vector address
(0008h or 0018h). Once in the Interrupt Service Routine, the source(s) of the interrupt can be determined
by polling the interrupt flag bits in the INTCONx and PIRx registers. The interrupt flag bits must be
cleared by software before re-enabling interrupts to avoid repeating the same interrupt.
The “return from interrupt” instruction, RETFIE, exits the interrupt routine and sets the GIE/GIEH bit
(GIEH or GIEL if priority levels are used), which re-enables interrupts.
For external interrupt events, such as the INT pins or the interrupt-on-change pins, the interrupt latency
will be three to four instruction cycles. The exact latency is the same for one-cycle or two-cycle
instructions. Individual interrupt flag bits are set, regardless of the status of their corresponding enable
bits or the Global Interrupt Enable bit.
Important:  Do not use the MOVFF instruction to modify any of the interrupt control registers
while any interrupt is enabled. Doing so may cause erratic microcontroller behavior.
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Figure 14-1. PIC18 Interrupt Logic
Filename: 10-000010B.vsd
Title: Generic Interrupt Logic for PIC18
Last Edit: 5/4/2016
First Used:
Rev. 10-000010B
5/4/2016
IPEN
IPEN
GIEL/PEIE
GIEH/GIE
IPEN
GIEH/GIE
GIEL/PEIE
Interrupt to
CPU Vector at
Location 0008h
Interrupt to
CPU Vector at
Location 0018h
Wake-up if in
Idle or Sleep
modes
High Priority Interrupt Generation
Low Priority Interrupt Generation
PIR0
IPR0
PIE0
PIR0
IPR0
PIE0
PIR1
IPR1
PIE1
PIR2
IPR2
PIE2
PIRx
IPRx
PIEx
PIR1
IPR1
PIE1
PIR2
IPR2
PIE2
PIRx
IPRx
PIEx
14.4 INTCON Registers
The INTCON registers are readable and writable registers, which contain various enable and priority bits.
14.5 PIR Registers
The PIR registers contain the individual flag bits for the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are 8 PIR registers.
14.6 PIE Registers
The PIE registers contain the individual enable bits for the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are 8 Peripheral Interrupt Enable registers. When IPEN = 0, the PEIE/
GIEL bit must be set to enable any of these peripheral interrupts.
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14.7 IPR Registers
The IPR registers contain the individual priority bits for the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are 8 Peripheral Interrupt Priority registers. Using the priority bits
requires that the Interrupt Priority Enable (IPEN) bit be set.
14.8 INTn Pin Interrupts
PIC18F26/45/46Q10 devices have 3 external interrupt sources which can be assigned to any pin on
PORTA and PORTB using PPS. The external interrupt sources are edge-triggered. If the corresponding
INTxEDG bit in the 14.13.1 INTCON register is set (= 1), the interrupt is triggered by a rising edge. It the
bit is clear, the trigger is on the falling edge.
All external interrupts (INT0, INT1, INT2) can wake-up the processor from Idle or Sleep modes if bit
INTxE was set prior to going into those modes. If the Global Interrupt Enable bit (GIE/GIEH) is set, the
processor will branch to the interrupt vector following wake-up.
Interrupt priority is determined by the value contained in the corresponding interrupt priority bit (INT0P,
INT1P, INT2P) of the 14.13.18 IPR0 register.
14.9 TMR0 Interrupt
In 8-bit mode (which is the default), an overflow in the TMR0 register (FFh → 00h) will set flag bit,
TMR0IF. In 16-bit mode, an overflow in the TMR0H:TMR0L register pair (FFFFh → 0000h) will set
TMR0IF. The interrupt can be enabled/disabled by setting/clearing enable bit, TMR0IE. Interrupt priority
for Timer0 is determined by the value contained in the interrupt priority bit, TMR0IP. See “Timer0 Module”
for further details on the Timer0 module.
14.10 Interrupt-on-Change
An input change on any port pins that support IOC sets Flag bit, IOCIF. The interrupt can be enabled/
disabled by setting/clearing the enable bit, IOCIE. Pins must also be individually enabled in the IOCxP
and IOCxN register. IOCIF is a read-only bit and the flag can be cleared by clearing the corresponding
IOCxF registers. For more information, refer to chapter “Interrupt-on-Change”.
Related Links
16. Interrupt-on-Change
14.11 Context Saving During Interrupts
During interrupts, the return PC address is saved on the stack. Additionally, the WREG, STATUS and
BSR registers are saved on the fast return stack. If a fast return from interrupt is not used the user may
need to save the WREG, STATUS and BSR registers on entry to the Interrupt Service Routine.
Depending on the user’s application, other registers may also need to be saved. Saving Status, WREG
and BSR Registers in RAM saves and restores the WREG, STATUS and BSR registers during an
Interrupt Service Routine.
Example 14-1. Saving Status, WREG and BSR Registers in RAM
MOVWF W_TEMP ; W_TEMP is in virtual bank
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MOVFF STATUS, STATUS_TEMP ; STATUS_TEMP located anywhere
MOVFF BSR, BSR_TEMP ; BSR_TEMP located anywhere
;
; USER ISR CODE
;
MOVFF BSR_TEMP, BSR ; Restore BSR
MOVF W_TEMP, W ; Restore WREG
MOVFF STATUS_TEMP, STATUS ; Restore STATUS
Related Links
10.1.2.5 Fast Register Stack
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14.12 Register Summary - Interrupt Control
Address Name Bit Pos.
0x0EB5 IPR0 7:0 TMR0IP IOCIP INT2IP INT1IP INT0IP
0x0EB6 IPR1 7:0 OSCFIP CSWIP ADTIP ADIP
0x0EB7 IPR2 7:0 HLVDIP ZCDIP C2IP C1IP
0x0EB8 IPR3 7:0 RC2IP TX2IP RC1IP TX1IP BCL2IP SSP2IP BCL1IP SSP1IP
0x0EB9 IPR4 7:0 TMR6IP TMR5IP TMR4IP TMR3IP TMR2IP TMR1IP
0x0EBA IPR5 7:0 CLC4IP CLC3IP CLC2IP CLC1IP TMR5GIP TMR3GIP TMR1GIP
0x0EBB IPR6 7:0 CLC8IP CLC7IP CLC6IP CLC5IP CCP2IP CCP1IP
0x0EBC IPR7 7:0 SCANIP CRCIP NVMIP CWG1IP
0x0EBD PIE0 7:0 TMR0IE IOCIE INT2IE INT1IE INT0IE
0x0EBE PIE1 7:0 OSCFIE CSWIE ADTIE ADIE
0x0EBF PIE2 7:0 HLVDIE ZCDIE C2IE C1IE
0x0EC0 PIE3 7:0 RC2IE TX2IE RC1IE TX1IE BCL2IE SSP2IE BCL1IE SSP1IE
0x0EC1 PIE4 7:0 TMR6IE TMR5IE TMR4IE TMR3IE TMR2IE TMR1IE
0x0EC2 PIE5 7:0 CLC4IE CLC3IE CLC2IE CLC1IE TMR5GIE TMR3GIE TMR1GIE
0x0EC3 PIE6 7:0 CLC8IE CLC7IE CLC6IE CLC5IE CCP2IE CCP1IE
0x0EC4 PIE7 7:0 SCANIE CRCIE NVMIE CWG1IE
0x0EC5 PIR0 7:0 TMR0IF IOCIF INT2IF INT1IF INT0IF
0x0EC6 PIR1 7:0 OSCFIF CSWIF ADTIF ADIF
0x0EC7 PIR2 7:0 HLVDIF ZCDIF C2IF C1IF
0x0EC8 PIR3 7:0 RC2IF TX2IF RC1IF TX1IF BCL2IF SSP2IF BCL1IF SSP1IF
0x0EC9 PIR4 7:0 TMR6IF TMR5IF TMR4IF TMR3IF TMR2IF TMR1IF
0x0ECA PIR5 7:0 CLC4IF CLC3IF CLC2IF CLC1IF TMR5GIF TMR3GIF TMR1GIF
0x0ECB PIR6 7:0 CLC8IF CLC7IF CLC6IF CLC5IF CCP2IF CCP1IF
0x0ECC PIR7 7:0 SCANIF CRCIF NVMIF CWG1IF
0x0ECD
...
0x0FF1
Reserved
0x0FF2 INTCON 7:0 GIE/GIEH PEIE/GIEL IPEN INT2EDG INT1EDG INT0EDG
14.13 Register Definitions: Interrupt Control
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14.13.1 INTCON
Name:  INTCON
Address:  0xFF2
Interrupt Control Register
Bit 7 6 5 4 3 2 1 0
GIE/GIEH PEIE/GIEL IPEN INT2EDG INT1EDG INT0EDG
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 1 1 1
Bit 7 – GIE/GIEH Global Interrupt Enable bit
Value Condition Description
1If IPEN = 1 Enables all unmasked interrupts and cleared by hardware for high-priority
interrupts only
0If IPEN = 1 Disables all interrupts
1If IPEN = 0 Enables all unmasked interrupts and cleared by hardware for all interrupts
0If IPEN = 0 Disables all interrupts
Bit 6 – PEIE/GIEL Peripheral Interrupt Enable bit
Value Condition Description
1If IPEN = 1 Enables all low-priority interrupts and cleared by hardware for low-priority
interrupts only
0If IPEN = 1 Disables all low-priority interrupts
1If IPEN = 0 Enables all unmasked peripheral interrupts
0If IPEN = 0 Disables all peripheral interrupts
Bit 5 – IPEN Interrupt Priority Enable bit
Value Description
1Enable priority levels on interrupts
0Disable priority levels on interrupts
Bits 0, 1, 2 – INTxEDG External Interrupt ‘x’ Edge Select bit
Value Description
1Interrupt on rising edge of INTx pin
0Interrupt on falling edge of INTx pin
Important:  Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its
corresponding enable bit or the global enable bit. User software should ensure the appropriate interrupt
flag bits are clear prior to enabling an interrupt. This feature allows for software polling.
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14.13.2 PIR0
Name:  PIR0
Address:  0xEC5
Peripheral Interrupt Request (Flag) Register 0
Bit 7 6 5 4 3 2 1 0
TMR0IF IOCIF INT2IF INT1IF INT0IF
Access R/W R R/W R/W R/W
Reset 0 0 0 0 0
Bit 5 – TMR0IF  Timer0 Interrupt Flag bit(1)
Value Description
1TMR0 register has overflowed (must be cleared by software)
0TMR0 register has not overflowed
Bit 4 – IOCIF  Interrupt-on-Change Flag bit(1,2)
Value Description
1IOC event has occurred (must be cleared by software)
0IOC event has not occurred
Bits 0, 1, 2 – INTxIF  External Interrupt ‘x’ Flag bit(1,3)
Value Description
1External Interrupt ‘x’ has occurred
0External Interrupt ‘x’ has not occurred
Note: 
1. Interrupts are not disabled by the PEIE bit.
2. IOCIF is a read-only bit; to clear the interrupt condition, all bits in the IOCF register must be
cleared.
3. The external interrupt GPIO pin is selected by the INTPPS register.
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14.13.3 PIR1
Name:  PIR1
Address:  0xEC6
Peripheral Interrupt Request (Flag) Register 1
Bit 7 6 5 4 3 2 1 0
OSCFIF CSWIF ADTIF ADIF
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – OSCFIF Oscillator Fail Interrupt Flag bit
Value Description
1Device oscillator failed, clock input has changed to HFINTOSC (must be cleared by
software)
0Device clock operating
Bit 6 – CSWIF  Clock-Switch Interrupt Flag bit(1)
Value Description
1New oscillator is ready for switch (must be cleared by software)
0New oscillator is not ready for switch or has not been started
Bit 1 – ADTIF ADC Threshold Interrupt Flag bit
Value Description
1ADC Threshold interrupt has occurred (must be cleared by software)
0ADC Threshold event is not complete or has not been started
Bit 0 – ADIF ADC Interrupt Flag bit
Value Description
1An A/D conversion completed (must be cleared by software)
0The A/D conversion is not complete or has not been started
Note: 
1. The CSWIF interrupt will not wake the system from Sleep. The system will Sleep until another
interrupt causes the wake-up.
Related Links
4.3.3 Clock Switch and Sleep
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14.13.4 PIR2
Name:  PIR2
Address:  0xEC7
Peripheral Interrupt Request (Flag) Register 2
Bit 7 6 5 4 3 2 1 0
HLVDIF ZCDIF C2IF C1IF
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – HLVDIF HLVD Interrupt Flag bit
Value Description
1HLVD interrupt event has occurred
0HLVD interrupt event has not occurred or has not been set up
Bit 6 – ZCDIF Zero-Cross Detect Interrupt Flag bit
Value Description
1ZCD Output has changed (must be cleared in software)
0ZCD Output has not changed
Bits 0, 1 – CxIF Comparator ‘x’ Interrupt Flag bit
Value Description
1Comparator Cx output has changed (must be cleared by software)
0Comparator Cx output has not changed
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14.13.5 PIR3
Name:  PIR3
Address:  0xEC8
Peripheral Interrupt Request (Flag) Register 3
Bit 7 6 5 4 3 2 1 0
RC2IF TX2IF RC1IF TX1IF BCL2IF SSP2IF BCL1IF SSP1IF
Access R R R R R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 5, 7 – RCxIF EUSARTx Receive Interrupt Flag bit
Value Description
1The EUSARTx receive buffer, RCxREG, is full (cleared by reading RCxREG)
0The EUSARTx receive buffer is empty
Bits 4, 6 – TXxIF EUSARTx Transmit Interrupt Flag bit
Value Description
1The EUSARTx transmit buffer, TXxREG, is empty (cleared by writing TXxREG)
0The EUSARTx transmit buffer is full
Bits 1, 3 – BCLxIF MSSPx Bus Collision Interrupt Flag bit
Value Description
1A bus collision has occurred while the MSSPx module configured in I2C master was
transmitting (must be cleared in software)
0No bus collision occurred
Bits 0, 2 – SSPxIF Synchronous Serial Port ‘x’ Interrupt Flag bit
Value Description
1The transmission/reception is complete (must be cleared in software)
0Waiting to transmit/receive
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14.13.6 PIR4
Name:  PIR4
Address:  0xEC9
Peripheral Interrupt Request (Flag) Register 4
Bit 7 6 5 4 3 2 1 0
TMR6IF TMR5IF TMR4IF TMR3IF TMR2IF TMR1IF
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 5 – TMR6IF TMR6 to PR6 Match Interrupt Flag bit
Value Description
1TMR6 to PR6 match occurred (must be cleared in software)
0No TMR6 to PR6 match occurred
Bit 4 – TMR5IF TMR5 Overflow Interrupt Flag bit
Value Description
1TMR5 register overflowed (must be cleared in software)
0TMR5 register did not overflow
Bit 3 – TMR4IF TMR4 to PR4 Match Interrupt Flag bit
Value Description
1TMR4 to PR4 match occurred (must be cleared in software)
0No TMR4 to PR4 match occurred
Bit 2 – TMR3IF TMR3 Overflow Interrupt Flag bit
Value Description
1TMR3 register overflowed (must be cleared in software)
0TMR3 register did not overflow
Bit 1 – TMR2IF TMR2 to PR2 Match Interrupt Flag bit
Value Description
1TMR2 to PR2 match occurred (must be cleared in software)
0No TMR2 to PR2 match occurred
Bit 0 – TMR1IF TMR1 Overflow Interrupt Flag bit
Value Description
1TMR1 register overflowed (must be cleared in software)
0TMR1 register did not overflow
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14.13.7 PIR5
Name:  PIR5
Address:  0xECA
Peripheral Interrupt Request (Flag) Register 5
Bit 7 6 5 4 3 2 1 0
CLC4IF CLC3IF CLC2IF CLC1IF TMR5GIF TMR3GIF TMR1GIF
Access R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bits 4, 5, 6, 7 – CLCxIF CLCx Interrupt Flag bit
Value Description
1A CLCx interrupt occurred
0No CLCx interrupt occurred
Bit 2 – TMR5GIF TMR5 Gate Interrupt Flag bit
Value Description
1TMR5 gate interrupt occurred (must be cleared in software)
0No TMR5 gate occurred
Bit 1 – TMR3GIF TMR3 Gate Interrupt Flag bit
Value Description
1TMR3 gate interrupt occurred (must be cleared in software)
0No TMR3 gate occurred
Bit 0 – TMR1GIF TMR1 Gate Interrupt Flag bit
Value Description
1TMR1 gate interrupt occurred (must be cleared in software)
0No TMR1 gate occurred
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14.13.8 PIR6
Name:  PIR6
Address:  0xECB
PIR6 Peripheral Interrupt Request (Flag) Register 6
Bit 7 6 5 4 3 2 1 0
CLC8IF CLC7IF CLC6IF CLC5IF CCP2IF CCP1IF
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bits 4, 5, 6, 7 – CLCyIF CLCx Interrupt Flag bit
Value Description
1A CLCx interrupt occurred
0No CLCx interrupt occurred
Bit 1 – CCP2IF ECCP2 Interrupt Flag bit
Value Condition Description
1Capture mode A TMR register capture occurred (must be cleared in software)
0Capture mode No TMR register capture occurred
1Compare mode A TMR register compare match occurred (must be cleared in software)
0Compare mode No TMR register compare match occurred
PWM mode Unused in PWM mode
Bit 0 – CCP1IF ECCP1 Interrupt Flag bit
Value Condition Description
1Capture mode A TMR register capture occurred (must be cleared in software)
0Capture mode No TMR register capture occurred
1Compare mode A TMR register compare match occurred (must be cleared in software)
0Compare mode No TMR register compare match occurred
PWM mode Unused in PWM mode
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14.13.9 PIR7
Name:  PIR7
Address:  0xECC
Peripheral Interrupt Request (Flag) Register 7
Bit 7 6 5 4 3 2 1 0
SCANIF CRCIF NVMIF CWG1IF
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – SCANIF SCAN Interrupt Flag bit
Value Description
1SCAN interrupt has occurred (must be cleared in software)
0SCAN interrupt has not occurred or has not been started
Bit 6 – CRCIF CRC Interrupt Flag bit
Value Description
1CRC interrupt has occurred (must be cleared in software)
0CRC interrupt has not occurred or has not been started
Bit 5 – NVMIF NVM Interrupt Flag bit
Value Description
1NVM interrupt has occurred (must be cleared in software)
0NVM interrupt has not occurred or has not been started
Bit 0 – CWG1IF CWG Interrupt Flag bit
Value Description
1CWG interrupt has occurred (must be cleared in software)
0CWG interrupt has not occurred or has not been started
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 220
14.13.10 PIE0
Name:  PIE0
Address:  0xEBD
Peripheral Interrupt Enable Register 0
Bit 7 6 5 4 3 2 1 0
TMR0IE IOCIE INT2IE INT1IE INT0IE
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bit 5 – TMR0IE  Timer0 Interrupt Enable bit(1)
Value Description
1Enabled
0Disabled
Bit 4 – IOCIE  Interrupt-on-Change Enable bit(1)
Value Description
1Enabled
0Disabled
Bits 0, 1, 2 – INTxIE  External Interrupt ‘x’ Enable bit(1)
Value Description
1Enabled
0Disabled
Note: 
1. PIR0 interrupts are not disabled by the PEIE bit in the INTCON register.
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14.13.11 PIE1
Name:  PIE1
Address:  0xEBE
Peripheral Interrupt Enable Register 1
Bit 7 6 5 4 3 2 1 0
OSCFIE CSWIE ADTIE ADIE
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – OSCFIE Oscillator Fail Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 6 – CSWIE Clock-Switch Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 1 – ADTIE ADC Threshold Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 0 – ADIE ADC Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.12 PIE2
Name:  PIE2
Address:  0xEBF
Peripheral Interrupt Enable Register 2
Bit 7 6 5 4 3 2 1 0
HLVDIE ZCDIE C2IE C1IE
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – HLVDIE HLVD Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 6 – ZCDIE Zero-Cross Detect Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bits 0, 1 – CxIE Comparator ‘x’ Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.13 PIE3
Name:  PIE3
Address:  0xEC0
Peripheral Interrupt Enable Register 3
Bit 7 6 5 4 3 2 1 0
RC2IE TX2IE RC1IE TX1IE BCL2IE SSP2IE BCL1IE SSP1IE
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 5, 7 – RCxIE EUSARTx Receive Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bits 4, 6 – TXxIE EUSARTx Transmit Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bits 1, 3 – BCLxIE MSSPx Bus Collision Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bits 0, 2 – SSPxIE Synchronous Serial Port ‘x’ Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.14 PIE4
Name:  PIE4
Address:  0xEC1
Peripheral Interrupt Enable Register 4
Bit 7 6 5 4 3 2 1 0
TMR6IE TMR5IE TMR4IE TMR3IE TMR2IE TMR1IE
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 5 – TMR6IE TMR6 to PR6 Match Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 4 – TMR5IE TMR5 Overflow Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 3 – TMR4IE TMR4 to PR4 Match Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 2 – TMR3IE TMR3 Overflow Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 1 – TMR2IE TMR2 to PR2 Match Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 0 – TMR1IE TMR1 Overflow Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.15 PIE5
Name:  PIE5
Address:  0xEC2
Peripheral Interrupt Enable Register 5
Bit 7 6 5 4 3 2 1 0
CLC4IE CLC3IE CLC2IE CLC1IE TMR5GIE TMR3GIE TMR1GIE
Access R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bits 4, 5, 6, 7 – CLCxIE CLCx Interrupt Enable bit
Value Description
1CLCx Interrupt Enabled
0CLCx Interrupt Disabled
Bit 2 – TMR5GIE TMR5 Gate Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 1 – TMR3GIE TMR3 Gate Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 0 – TMR1GIE TMR1 Gate Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.16 PIE6
Name:  PIE6
Address:  0xEC3
Peripheral Interrupt Enable Register 6
Bit 7 6 5 4 3 2 1 0
CLC8IE CLC7IE CLC6IE CLC5IE CCP2IE CCP1IE
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bits 4, 5, 6, 7 – CLCyIE CLCx Interrupt Enable bit
Value Description
1CLCx Interrupts Enabled
0CLCx Interrupts Disabled
Bit 1 – CCP2IE ECCP2 Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 0 – CCP1IE ECCP1 Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.17 PIE7
Name:  PIE7
Address:  0xEC4
Peripheral Interrupt Enable Register 7
Bit 7 6 5 4 3 2 1 0
SCANIE CRCIE NVMIE CWG1IE
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – SCANIE SCAN Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 6 – CRCIE CRC Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 5 – NVMIE NVM Interrupt Enable bit
Value Description
1Enabled
0Disabled
Bit 0 – CWG1IE CWG Interrupt Enable bit
Value Description
1Enabled
0Disabled
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14.13.18 IPR0
Name:  IPR0
Address:  0xEB5
Peripheral Interrupt Priority Register 0
Bit 7 6 5 4 3 2 1 0
TMR0IP IOCIP INT2IP INT1IP INT0IP
Access R/W R/W R/W R/W R/W
Reset 1 1 0 0 1
Bit 5 – TMR0IP Timer0 Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 4 – IOCIP Interrupt-on-Change Priority bit
Value Description
1High priority
0Low priority
Bits 0, 1, 2 – INTxIP External Interrupt ‘x’ Priority bit
Value Description
1High priority
0Low priority
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14.13.19 IPR1
Name:  IPR1
Address:  0xEB6
Peripheral Interrupt Priority Register 1
Bit 7 6 5 4 3 2 1 0
OSCFIP CSWIP ADTIP ADIP
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bit 7 – OSCFIP Oscillator Fail Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 6 – CSWIP Clock-Switch Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 1 – ADTIP ADC Threshold Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 0 – ADIP ADC Interrupt Priority bit
Value Description
1High priority
0Low priority
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14.13.20 IPR2
Name:  IPR2
Address:  0xEB7
Peripheral Interrupt Priority Register 2
Bit 7 6 5 4 3 2 1 0
HLVDIP ZCDIP C2IP C1IP
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bit 7 – HLVDIP HLVD Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 6 – ZCDIP Zero-Cross Detect Interrupt Priority bit
Value Description
1High priority
0Low priority
Bits 0, 1 – CxIP Comparator ‘x’ Interrupt Priority bit
Value Description
1High priority
0Low priority
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14.13.21 IPR3
Name:  IPR3
Address:  0xEB8
Peripheral Interrupt Priority Register 3
Bit 7 6 5 4 3 2 1 0
RC2IP TX2IP RC1IP TX1IP BCL2IP SSP2IP BCL1IP SSP1IP
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 1 1 0 0 1 1
Bits 5, 7 – RCxIP EUSARTx Receive Interrupt Priority bit
Value Description
1High priority
0Low priority
Bits 4, 6 – TXxIP EUSARTx Transmit Interrupt Priority bit
Value Description
1High priority
0Low priority
Bits 1, 3 – BCLxIP MSSPx Bus Collision Interrupt Priority bit
Value Description
1High priority
0Low priority
Bits 0, 2 – SSPxIP Synchronous Serial Port 'x' Interrupt Priority bit
Value Description
1High priority
0Low priority
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 232
14.13.22 IPR4
Name:  IPR4
Address:  0xEB9
Peripheral Interrupt Priority Register 4
Bit 7 6 5 4 3 2 1 0
TMR6IP TMR5IP TMR4IP TMR3IP TMR2IP TMR1IP
Access R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1
Bit 5 – TMR6IP TMR6 to PR6 Match Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 4 – TMR5IP TMR5 Overflow Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 3 – TMR4IP TMR4 to PR4 Match Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 2 – TMR3IP TMR3 Overflow Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 1 – TMR2IP TMR2 to PR2 Match Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 0 – TMR1IP TMR1 Overflow Interrupt Priority bit
Value Description
1High priority
0Low priority
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 233
14.13.23 IPR5
Name:  IPR5
Address:  0xEBA
Peripheral Interrupt Priority Register 5
Bit 7 6 5 4 3 2 1 0
CLC4IP CLC3IP CLC2IP CLC1IP TMR5GIP TMR3GIP TMR1GIP
Access R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 1 1 1
Bits 4, 5, 6, 7 – CLCxIP CLCx Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 2 – TMR5GIP TMR5 Gate Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 1 – TMR3GIP TMR3 Gate Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 0 – TMR1GIP TMR1 Gate Interrupt Priority bit
Value Description
1High priority
0Low priority
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 234
14.13.24 IPR6
Name:  IPR6
Address:  0xEBB
Peripheral Interrupt Priority Register
Bit 7 6 5 4 3 2 1 0
CLC8IP CLC7IP CLC6IP CLC5IP CCP2IP CCP1IP
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 1 1
Bits 4, 5, 6, 7 – CLCyIP CLCx Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 1 – CCP2IP ECCP2 Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 0 – CCP1IP ECCP1 Interrupt Priority bit
Value Description
1High priority
0Low priority
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 235
14.13.25 IPR7
Name:  IPR7
Address:  0xEBC
Peripheral Interrupt Priority Register
Bit 7 6 5 4 3 2 1 0
SCANIP CRCIP NVMIP CWG1IP
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bit 7 – SCANIP SCAN Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 6 – CRCIP CRC Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 5 – NVMIP NVM Interrupt Priority bit
Value Description
1High priority
0Low priority
Bit 0 – CWG1IP CWG Interrupt Priority bit
Value Description
1High priority
0Low priority
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 236
15. I/O Ports
Table 15-1. Port Availability per Device
Device PORTA PORTB PORTC PORTD PORTE
PIC18F26Q10
PIC18F45/46Q10
Each port has eight registers to control the operation. These registers are:
PORTx registers (reads the levels on the pins of the device)
LATx registers (output latch)
TRISx registers (data direction)
ANSELx registers (analog select)
WPUx registers (weak pull-up)
INLVLx (input level control)
SLRCONx registers (slew rate control)
ODCONx registers (open-drain control)
Most port pins share functions with device peripherals, both analog and digital. In general, when a
peripheral is enabled on a port pin, that pin cannot be used as a general purpose output; however, the pin
can still be read.
The Data Latch (LATx registers) is useful for read-modify-write operations on the value that the I/O pins
are driving.
A write operation to the LATx register has the same effect as a write to the corresponding PORTx
register. A read of the LATx register reads of the values held in the I/O PORT latches, while a read of the
PORTx register reads the actual I/O pin value.
Ports that support analog inputs have an associated ANSELx register. When an ANSELx bit is set, the
digital input buffer associated with that bit is disabled.
Disabling the input buffer prevents analog signal levels on the pin between a logic high and low from
causing excessive current in the logic input circuitry. A simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in the following figure:
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I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 237
Figure 15-1. Generic I/O Port Operation
QD
CK
Write LATx
Data Register
I/O pin
Read PORTx
Write PORTx
TRISx
Read LATx
Data Bus
To digital peripherals
ANSELx
VDD
VSS
To analog peripherals
15.1 I/O Priorities
Each pin defaults to the PORT data latch after Reset. Other functions are selected with the peripheral pin
select logic. See “Peripheral Pin Select (PPS) Module” for more information.
Analog input functions, such as ADC and comparator inputs, are not shown in the peripheral pin select
lists. These inputs are active when the I/O pin is set for Analog mode using the ANSELx register. Digital
output functions may continue to control the pin when it is in Analog mode.
Analog outputs, when enabled, take priority over digital outputs and force the digital output driver into a
high-impedance state.
The pin function priorities are as follows:
1. Configuration bits
2. Analog outputs (disable the input buffers)
3. Analog inputs
4. Port inputs and outputs from PPS
Related Links
17. (PPS) Peripheral Pin Select Module
15.2 PORTx Registers
In this section the generic names such as PORTx, LATx, TRISx, etc. can be associated with all ports. For
availability of PORTD refer to Table 15-1. The functionality of PORTE is different compared to other ports
and is explained in a separate section.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 238
15.2.1 Data Register
PORTx is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISx. Setting a
TRISx bit (‘1’) will make the corresponding PORTA pin an input (i.e., disable the output driver). Clearing a
TRISx bit (‘0’) will make the corresponding PORTx pin an output (i.e., it enables output driver and puts
the contents of the output latch on the selected pin). Example 15-1 shows how to initialize PORTA.
Reading the PORTx register reads the status of the pins, whereas writing to it will write to the PORT
latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then written to the PORT data latch (LATx).
The PORT data latch LATx holds the output port data and contains the latest value of a LATx or PORTx
write.
Example 15-1. EXAMPLE-1: Initializing PORTA
; This code example illustrates initializing the PORTA register.
; The other ports are initialized in the same manner.
CLRF LATA ; Set all output bits to zero
MOVLW B'11111000' ; Set RA<7:3> as inputs and RA<2:0> as outputs
MOVWF TRISA ;
BANKSEL ANSELA
CLRF ANSELA ; All pins are digital I/O
15.2.2 Direction Control
The TRISx register controls the PORTx pin output drivers, even when they are being used as analog
inputs. The user should ensure the bits in the TRISx register are maintained set when using them as
analog inputs. I/O pins configured as analog inputs always read ‘0’.
Related Links
15.5.6 TRISA
15.5.7 TRISB
15.5.8 TRISC
15.5.9 TRISD
15.5.10 TRISE
15.2.3 Analog Control
The ANSELx register is used to configure the Input mode of an I/O pin to analog. Setting the appropriate
ANSELx bit high will cause all digital reads on the pin to be read as ‘0’ and allow analog functions on the
pin to operate correctly.
The state of the ANSELx bits has no effect on digital output functions. A pin with TRIS clear and ANSEL
set will still operate as a digital output, but the Input mode will be analog. This can cause unexpected
behavior when executing READ-MODIFY-WRITE instructions on the affected port.
Important:  The ANSELx bits default to the Analog mode after Reset. To use any pins as digital
general purpose or peripheral inputs, the corresponding ANSEL bits must be initialized to ‘0’ by
user software.
Related Links
15.5.16 ANSELA
15.5.17 ANSELB
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 239
15.5.19 ANSELD
15.5.20 ANSELE
15.2.4 Open-Drain Control
The ODCONx register controls the open-drain feature of the port. Open-drain operation is independently
selected for each pin. When an ODCONx bit is set, the corresponding port output becomes an open-drain
driver capable of sinking current only. When an ODCONx bit is cleared, the corresponding port output pin
is the standard push-pull drive capable of sourcing and sinking current.
Important:  It is not necessary to set open-drain control when using the pin for I2C; the I2C
module controls the pin and makes the pin open-drain.
Related Links
15.5.26 ODCONA
15.5.27 ODCONB
15.5.28 ODCONC
15.5.29 ODCOND
15.5.30 ODCONE
15.2.5 Slew Rate Control
The SLRCONx register controls the slew rate option for each port pin. Slew rate for each port pin can be
controlled independently. When an SLRCONx bit is set, the corresponding port pin drive is slew rate
limited. When an SLRCONx bit is cleared, The corresponding port pin drive slews at the maximum rate
possible.
Related Links
15.5.31 SLRCONA
15.5.32 SLRCONB
15.5.33 SLRCONC
15.5.34 SLRCOND
15.5.35 SLRCONE
15.2.6 Input Threshold Control
The INLVLx register controls the input voltage threshold for each of the available PORTx input pins. A
selection between the Schmitt Trigger CMOS or the TTL compatible thresholds is available. The input
threshold is important in determining the value of a read of the PORTx register and also the level at which
an interrupt-on-change occurs, if that feature is enabled. See link below for more information on threshold
levels.
Important:  Changing the input threshold selection should be performed while all peripheral
modules are disabled. Changing the threshold level during the time a module is active may
inadvertently generate a transition associated with an input pin, regardless of the actual voltage
level on that pin.
Related Links
15.5.36 INLVLA
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 240
15.5.37 INLVLB
15.5.38 INLVLC
15.5.39 INLVLD
15.5.40 INLVLE
15.2.7 Weak Pull-up Control
The WPUx register controls the individual weak pull-ups for each port pin.
Related Links
15.5.21 WPUA
15.5.22 WPUB
15.5.23 WPUC
15.5.24 WPUD
15.5.25 WPUE
15.2.8 Edge Selectable Interrupt-on-Change
An interrupt can be generated by detecting a signal at the port pin that has either a rising edge or a falling
edge. Individual pins can be independently configured to generate an interrupt. The interrupt-on-change
module is present on all the pins that are common between 28-pin and 40/44-pin devices. For further
details about the IOC module, refer to "Interrupt-on-Change" chapter.
Related Links
16. Interrupt-on-Change
15.3 PORTE Registers
Depending on the device selected, PORTE is implemented in two different ways.
15.3.1 PORTE on 40/44-Pin Devices
For 40/44-pin devices, PORTE is a 4-bit wide port. Three pins (RE0, RE1 and RE2) are individually
configurable as inputs or outputs. These pins have Schmitt Trigger input buffers. When selected as an
analog input, these pins will read as ‘0’s.
The corresponding data direction register is TRISE. Setting a TRISE bit (= 1) will make the corresponding
PORTE pin an input (i.e., disable the output driver). Clearing a TRISE bit (= 0) will make the
corresponding PORTE pin an output (i.e., enable the output driver and put the contents of the output latch
on the selected pin).
TRISE controls the direction of the REx pins, even when they are being used as analog pins. The user
must make sure to keep the pins configured as inputs when using them as analog inputs. RE<2:0> bits
have other registers associated with them (i.e., ANSELE, WPUE, INLVLE, SLRCONE and ODCONE).
The functionality is similar to the other ports.
The Data Latch register (LATE) is also memory-mapped. Read-modify-write operations on the LATE
register read and write the latched output value for PORTE.
Important:  On a Power-on Reset, RE<2:0> are configured as analog inputs.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 241
The fourth pin of PORTE (MCLR/VPP/RE3) is an input-only pin. Its operation is controlled by the MCLRE
Configuration bit. When selected as a port pin (MCLRE = 0), it functions as a digital input-only pin; as
such, it does not have TRIS or LAT bits associated with its operation. Otherwise, it functions as the
device’s Master Clear input. In either configuration, RE3 also functions as the programming voltage input
during programming.
RE3 in PORTE register is a read-only bit and will read ‘1’ when MCLRE = 1 (i.e., Master Clear enabled).
Important:  On a Power-on Reset, RE3 is enabled as a digital input-only if Master Clear
functionality is disabled.
Example 15-2. EXAMPLE-2: Initializing PORTE
CLRF PORTE ; Initialize PORTE by
; clearing output
; data latches
CLRF LATE ; Alternate method
; to clear output
; data latches
CLRF ANSELE ; Configure analog pins
; for digital only
MOVLW 05h ; Value used to
; initialize data
; direction
MOVWF TRISE ; Set RE<0> as input
; RE<1> as output
; RE<2> as input
15.3.2 PORTE on 28-Pin Devices
For 28-pin devices, PORTE is only available when Master Clear functionality is disabled (MCLRE = 0). In
this case, PORTE is a single bit, input-only port comprised of RE3 only. The pin operates as previously
described. RE3 in PORTE register is a read-only bit and will read ‘1’ when MCLRE = 1 (i.e., Master Clear
enabled).
15.3.3 RE3 Weak Pull-Up
The port RE3 pin has an individually controlled weak internal pull-up. When set, the WPUE3 bit enables
the RE3 pin pull-up. When the RE3 port pin is configured as MCLR, (CONFIG2L, MCLRE = 1 and
CONFIG4H, LVP = 0), or configured for Low-Voltage Programming, (MCLRE = x and LVP = 1), the pull-
up is always enabled and the WPUE3 bit has no effect.
15.3.4 PORTE Interrupt-on-Change
The interrupt-on-change feature is available only on the RE3 pin for all devices.
Related Links
16. Interrupt-on-Change
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 242
15.4 Register Summary - Input/Output
Address Name Bit Pos.
0x0F08 INLVLA 7:0 INLVLA7 INLVLA6 INLVLA5 INLVLA4 INLVLA3 INLVLA2 INLVLA1 INLVLA0
0x0F09 SLRCONA 7:0 SLRA7 SLRA6 SLRA5 SLRA4 SLRA3 SLRA2 SLRA1 SLRA0
0x0F0A ODCONA 7:0 ODCA7 ODCA6 ODCA5 ODCA4 ODCA3 ODCA2 ODCA1 ODCA0
0x0F0B WPUA 7:0 WPUA7 WPUA6 WPUA5 WPUA4 WPUA3 WPUA2 WPUA1 WPUA0
0x0F0C ANSELA 7:0 ANSELA7 ANSELA6 ANSELA5 ANSELA4 ANSELA3 ANSELA2 ANSELA1 ANSELA0
0x0F0D
...
0x0F0F
Reserved
0x0F10 INLVLB 7:0 INLVLB7 INLVLB6 INLVLB5 INLVLB4 INLVLB3 INLVLB2 INLVLB1 INLVLB0
0x0F11 SLRCONB 7:0 SLRB7 SLRB6 SLRB5 SLRB4 SLRB3 SLRB2 SLRB1 SLRB0
0x0F12 ODCONB 7:0 ODCB7 ODCB6 ODCB5 ODCB4 ODCB3 ODCB2 ODCB1 ODCB0
0x0F13 WPUB 7:0 WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0
0x0F14 ANSELB 7:0 ANSELB7 ANSELB6 ANSELB5 ANSELB4 ANSELB3 ANSELB2 ANSELB1 ANSELB0
0x0F15
...
0x0F17
Reserved
0x0F18 INLVLC 7:0 INLVLC7 INLVLC6 INLVLC5 INLVLC4 INLVLC3 INLVLC2 INLVLC1 INLVLC0
0x0F19 SLRCONC 7:0 SLRC7 SLRC6 SLRC5 SLRC4 SLRC3 SLRC2 SLRC1 SLRC0
0x0F1A ODCONC 7:0 ODCC7 ODCC6 ODCC5 ODCC4 ODCC3 ODCC2 ODCC1 ODCC0
0x0F1B WPUC 7:0 WPUC7 WPUC6 WPUC5 WPUC4 WPUC3 WPUC2 WPUC1 WPUC0
0x0F1C ANSELC 7:0 ANSELC7 ANSELC6 ANSELC5 ANSELC4 ANSELC3 ANSELC2 ANSELC1 ANSELC0
0x0F1D INLVLD 7:0 INLVLD7 INLVLD6 INLVLD5 INLVLD4 INLVLD3 INLVLD2 INLVLD1 INLVLD0
0x0F1E SLRCOND 7:0 SLRD7 SLRD6 SLRD5 SLRD4 SLRD3 SLRD2 SLRD1 SLRD0
0x0F1F ODCOND 7:0 ODCD7 ODCD6 ODCD5 ODCD4 ODCD3 ODCD2 ODCD1 ODCD0
0x0F20 WPUD 7:0 WPUD7 WPUD6 WPUD5 WPUD4 WPUD3 WPUD2 WPUD1 WPUD0
0x0F21 ANSELD 7:0 ANSELD7 ANSELD6 ANSELD5 ANSELD4 ANSELD3 ANSELD2 ANSELD1 ANSELD0
0x0F22
...
0x0F24
Reserved
0x0F25 INLVLE 7:0 INLVLE3 INLVLE2 INLVLE1 INLVLE0
0x0F26 SLRCONE 7:0 SLRE2 SLRE1 SLRE0
0x0F27 ODCONE 7:0 ODCE2 ODCE1 ODCE0
0x0F28 WPUE 7:0 WPUE3 WPUE2 WPUE1 WPUE0
0x0F29 ANSELE 7:0 ANSELE2 ANSELE1 ANSELE0
0x0F2A
...
0x0F81
Reserved
0x0F82 LATA 7:0 LATA7 LATA6 LATA5 LATA4 LATA3 LATA2 LATA1 LATA0
0x0F83 LATB 7:0 LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0
0x0F84 LATC 7:0 LATC7 LATC6 LATC5 LATC4 LATC3 LATC2 LATC1 LATC0
0x0F85 LATD 7:0 LATD7 LATD6 LATD5 LATD4 LATD3 LATD2 LATD1 LATD0
0x0F86 LATE 7:0 LATE2 LATE1 LATE0
0x0F87 TRISA 7:0 TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0
0x0F88 TRISB 7:0 TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0
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...........continued
Address Name Bit Pos.
0x0F89 TRISC 7:0 TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
0x0F8A TRISD 7:0 TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0
0x0F8B TRISE 7:0 TRISE3 TRISE2 TRISE1 TRISE0
0x0F8C PORTA 7:0 RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0
0x0F8D PORTB 7:0 RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0
0x0F8E PORTC 7:0 RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0
0x0F8F PORTD 7:0 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
0x0F90 PORTE 7:0 RE3 RE2 RE1 RE0
15.5 Register Definitions: Port Control
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15.5.1 PORTA
Name:  PORTA
Address:  0xF8C
PORTA Register
Note:  Writes to PORTA are actually written to the corresponding LATA register.
Reads from PORTA register return actual I/O pin values.
Bit 7 6 5 4 3 2 1 0
RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – RAn Port I/O Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
Value Description
1Port pin is ≥ VIH
0Port pin is ≤ VIL
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 245
15.5.2 PORTB
Name:  PORTB
Address:  0xF8D
PORTB Register
Bit 7 6 5 4 3 2 1 0
RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – RBn Port I/O Value bits
Note:  Bits RB6 and RB7 read ‘1’ while in Debug mode.
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
Value Description
1Port pin is ≥ VIH
0Port pin is ≤ VIL
Note:  Writes to PORTB are actually written to the corresponding LATB register.
Reads from PORTB register return actual I/O pin values.
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15.5.3 PORTC
Name:  PORTC
Address:  0xF8E
PORTC Register
Bit 7 6 5 4 3 2 1 0
RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – RCn Port I/O Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
Value Description
1Port pin is ≥ VIH
0Port pin is ≤ VIL
Note:  Writes to PORTC are actually written to the corresponding LATC register.
Reads from PORTC register return actual I/O pin values.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 247
15.5.4 PORTD
Name:  PORTD
Address:  0xF8F
PORTD Register
Bit 7 6 5 4 3 2 1 0
RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – RDn Port I/O Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
Value Description
1Port pin is ≥ VIH
0Port pin is ≤ VIL
Note:  Writes to PORTD are actually written to the corresponding LATD register.
Reads from PORTD register return actual I/O pin values.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 248
15.5.5 PORTE
Name:  PORTE
Address:  0xF90
PORTE Register
Note:  Writes to PORTE are actually written to the corresponding LATE register.
Reads from PORTE register return actual I/O pin values.
Bit 7 6 5 4 3 2 1 0
RE3 RE2 RE1 RE0
Access R/W R/W R/W R/W
Reset x x x x
Bits 0, 1, 2, 3 – REn Port I/O Value bits
Note: 
1. Bit RE3 is read-only, and will read ‘1’ when MCLRE = 1 (Master Clear enabled).
2. 28-pin package only has RE3 in this register.
Reset States: POR/BOR = xxxx
All Other Resets = uuuu
Value Description
1Port pin is ≥ VIH
0Port pin is ≤ VIL
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 249
15.5.6 TRISA
Name:  TRISA
Address:  0xF87
Tri-State Control Register
Bit 7 6 5 4 3 2 1 0
TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – TRISAn TRISA Port I/O Tri-state Control bits
Value Description
1Port output driver is disabled
0Port output driver is enabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 250
15.5.7 TRISB
Name:  TRISB
Address:  0xF88
Tri-State Control Register
Bit 7 6 5 4 3 2 1 0
TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – TRISBn TRISB Port I/O Tri-state Control bits
Note:  Bits TRISB6 and TRISB7 read ‘1’ while in Debug mode.
Value Description
1Port output driver is disabled
0Port output driver is enabled
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15.5.8 TRISC
Name:  TRISC
Address:  0xF89
Tri-State Control Register
Bit 7 6 5 4 3 2 1 0
TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – TRISCn TRISC Port I/O Tri-state Control bits
Value Description
1Port output driver is disabled
0Port output driver is enabled
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15.5.9 TRISD
Name:  TRISD
Address:  0xF8A
Tri-State Control Register
Bit 7 6 5 4 3 2 1 0
TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – TRISDn TRISD Port I/O Tri-state Control bits
Value Description
1Port output driver is disabled
0Port output driver is enabled
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15.5.10 TRISE
Name:  TRISE
Address:  0xF8B
Tri-State Control Register
Bit 7 6 5 4 3 2 1 0
TRISE3 TRISE2 TRISE1 TRISE0
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bits 0, 1, 2, 3 – TRISEn PortE I/O Tri-state Control bits
Note: 
1. Not available on 28-pin devices.
2. TRISE3 bit is read-only, and will read ‘1’.
Value Description
1Port output driver is disabled
0Port output driver is enabled
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15.5.11 LATA
Name:  LATA
Address:  0xF82
Output Latch Register
Bit 7 6 5 4 3 2 1 0
LATA7 LATA6 LATA5 LATA4 LATA3 LATA2 LATA1 LATA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – LATAn Output Latch A Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuuu
Note:  Writes to LATA are equivalent with writes to the corresponding PORTA register. Reads from LATA
register return register values, not I/O pin values.
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15.5.12 LATB
Name:  LATB
Address:  0xF83
Output Latch Register
Bit 7 6 5 4 3 2 1 0
LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – LATBn Output Latch B Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuuu
Note:  Writes to LATB are equivalent with writes to the corresponding PORTB register. Reads from LATB
register return register values, not I/O pin values.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 256
15.5.13 LATC
Name:  LATC
Address:  0xF84
Output Latch Register
Bit 7 6 5 4 3 2 1 0
LATC7 LATC6 LATC5 LATC4 LATC3 LATC2 LATC1 LATC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – LATCn Output Latch C Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuuu
Note:  Writes to LATC are equivalent with writes to the corresponding PORTC register. Reads from LATC
register return register values, not I/O pin values.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 257
15.5.14 LATD
Name:  LATD
Address:  0xF85
Output Latch Register
Bit 7 6 5 4 3 2 1 0
LATD7 LATD6 LATD5 LATD4 LATD3 LATD2 LATD1 LATD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 0, 1, 2, 3, 4, 5, 6, 7 – LATDn Output Latch D Value bits
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuuu
Note:  Writes to LATD are equivalent with writes to the corresponding PORTD register. Reads from LATD
register return register values, not I/O pin values.
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15.5.15 LATE
Name:  LATE
Address:  0xF86
Output Latch Register
Bit 7 6 5 4 3 2 1 0
LATE2 LATE1 LATE0
Access R/W R/W R/W
Reset x x x
Bits 0, 1, 2 – LATEn Output Latch E Value bits
Reset States: POR/BOR = xxx
All Other Resets = uuu
Note:  Writes to LATE are equivalent with writes to the corresponding PORTE register. Reads from LATE
register return register values, not I/O pin values.
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15.5.16 ANSELA
Name:  ANSELA
Address:  0xF0C
Analog Select Register
Bit 7 6 5 4 3 2 1 0
ANSELA7 ANSELA6 ANSELA5 ANSELA4 ANSELA3 ANSELA2 ANSELA1 ANSELA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ANSELAn Analog Select on Pins RA<7:0>
Value Description
1Digital Input buffers are disabled
0ST and TTL input buffers are enabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 260
15.5.17 ANSELB
Name:  ANSELB
Address:  0xF14
Reset:  0x00
Analog Select Register
Bit 7 6 5 4 3 2 1 0
ANSELB7 ANSELB6 ANSELB5 ANSELB4 ANSELB3 ANSELB2 ANSELB1 ANSELB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ANSELBn Analog Select on Pins RB<7:0>
Value Description
1Digital Input buffers are disabled
0ST and TTL input buffers are enabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 261
15.5.18 ANSELC
Name:  ANSELC
Address:  0xF1C
Analog Select Register
Bit 7 6 5 4 3 2 1 0
ANSELC7 ANSELC6 ANSELC5 ANSELC4 ANSELC3 ANSELC2 ANSELC1 ANSELC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ANSELCn Analog Select on Pins RC<7:0>
Value Description
1Digital Input buffers are disabled
0ST and TTL input buffers are enabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 262
15.5.19 ANSELD
Name:  ANSELD
Address:  0xF21
Analog Select Register
Bit 7 6 5 4 3 2 1 0
ANSELD7 ANSELD6 ANSELD5 ANSELD4 ANSELD3 ANSELD2 ANSELD1 ANSELD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ANSELDn Analog Select on Pins RD<7:0>
Value Description
1Digital Input buffers are disabled
0ST and TTL input buffers are enabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 263
15.5.20 ANSELE
Name:  ANSELE
Address:  0xF29
Analog Select Register
Bit 7 6 5 4 3 2 1 0
ANSELE2 ANSELE1 ANSELE0
Access R/W R/W R/W
Reset 1 1 1
Bits 0, 1, 2 – ANSELEn Analog Select on Pins RE<7:0>
Value Description
1Digital Input buffers are disabled
0ST and TTL input buffers are enabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 264
15.5.21 WPUA
Name:  WPUA
Address:  0xF0B
Weak Pull-up Register
Bit 7 6 5 4 3 2 1 0
WPUA7 WPUA6 WPUA5 WPUA4 WPUA3 WPUA2 WPUA1 WPUA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – WPUAn Weak Pull-up PORTA Control bits
Value Description
1Weak Pull-up enabled
0Weak Pull-up disabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 265
15.5.22 WPUB
Name:  WPUB
Address:  0xF13
Weak Pull-up Register
Bit 7 6 5 4 3 2 1 0
WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – WPUBn Weak Pull-up PORTA Control bits
Value Description
1Weak Pull-up enabled
0Weak Pull-up disabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 266
15.5.23 WPUC
Name:  WPUC
Address:  0xF1B
Weak Pull-up Register
Bit 7 6 5 4 3 2 1 0
WPUC7 WPUC6 WPUC5 WPUC4 WPUC3 WPUC2 WPUC1 WPUC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – WPUCn Weak Pull-up PORTC Control bits
Value Description
1Weak Pull-up enabled
0Weak Pull-up disabled
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 267
15.5.24 WPUD
Name:  WPUD
Address:  0xF20
Weak Pull-up Register
Bit 7 6 5 4 3 2 1 0
WPUD7 WPUD6 WPUD5 WPUD4 WPUD3 WPUD2 WPUD1 WPUD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – WPUDn Weak Pull-up PORTD Control bits
Value Description
1Weak Pull-up enabled
0Weak Pull-up disabled
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15.5.25 WPUE
Name:  WPUE
Address:  0xF28
Weak Pull-up Register
Bit 7 6 5 4 3 2 1 0
WPUE3 WPUE2 WPUE1 WPUE0
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 0, 1, 2, 3 – WPUEn Weak Pull-up PORTE Control bits
Note: 
1. If MCLRE = 1, the weak pull-up in RE3 is always enabled; bit WPUE3 is not affected.
2. 28-pin package only has WPUE3 bit.
Value Description
1Weak Pull-up enabled
0Weak Pull-up disabled
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15.5.26 ODCONA
Name:  ODCONA
Address:  0xF0A
Open-Drain Control Register
Bit 7 6 5 4 3 2 1 0
ODCA7 ODCA6 ODCA5 ODCA4 ODCA3 ODCA2 ODCA1 ODCA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ODCAn Open-Drain Configuration on Pins Rx<7:0>
Value Description
1Output drives only low-going signals (sink current only)
0Output drives both high-going and low-going signals (source and sink current)
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 270
15.5.27 ODCONB
Name:  ODCONB
Address:  0xF12
Open-Drain Control Register
Bit 7 6 5 4 3 2 1 0
ODCB7 ODCB6 ODCB5 ODCB4 ODCB3 ODCB2 ODCB1 ODCB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ODCBn Open-Drain Configuration on Pins Rx<7:0>
Value Description
1Output drives only low-going signals (sink current only)
0Output drives both high-going and low-going signals (source and sink current)
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15.5.28 ODCONC
Name:  ODCONC
Address:  0xF1A
Open-Drain Control Register
Bit 7 6 5 4 3 2 1 0
ODCC7 ODCC6 ODCC5 ODCC4 ODCC3 ODCC2 ODCC1 ODCC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ODCCn Open-Drain Configuration on Pins Rx<7:0>
Value Description
1Output drives only low-going signals (sink current only)
0Output drives both high-going and low-going signals (source and sink current)
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 272
15.5.29 ODCOND
Name:  ODCOND
Address:  0xF1F
Open-Drain Control Register
Bit 7 6 5 4 3 2 1 0
ODCD7 ODCD6 ODCD5 ODCD4 ODCD3 ODCD2 ODCD1 ODCD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ODCDn Open-Drain Configuration on Pins Rx<7:0>
Value Description
1Output drives only low-going signals (sink current only)
0Output drives both high-going and low-going signals (source and sink current)
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15.5.30 ODCONE
Name:  ODCONE
Address:  0xF27
Open-Drain Control Register
Bit 7 6 5 4 3 2 1 0
ODCE2 ODCE1 ODCE0
Access R/W R/W R/W
Reset 0 0 0
Bits 0, 1, 2 – ODCEn Open-Drain Configuration on Pins Rx<7:0>
Value Description
1Output drives only low-going signals (sink current only)
0Output drives both high-going and low-going signals (source and sink current)
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 274
15.5.31 SLRCONA
Name:  SLRCONA
Address:  0xF09
Slew Rate Control Register
Bit 7 6 5 4 3 2 1 0
SLRA7 SLRA6 SLRA5 SLRA4 SLRA3 SLRA2 SLRA1 SLRA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – SLRAn Slew Rate Control on Pins Rx<7:0>, respectively
Value Description
1Port pin slew rate is limited
0Port pin slews at maximum rate
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 275
15.5.32 SLRCONB
Name:  SLRCONB
Address:  0xF11
Slew Rate Control Register
Bit 7 6 5 4 3 2 1 0
SLRB7 SLRB6 SLRB5 SLRB4 SLRB3 SLRB2 SLRB1 SLRB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – SLRBn Slew Rate Control on Pins Rx<7:0>, respectively
Value Description
1Port pin slew rate is limited
0Port pin slews at maximum rate
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 276
15.5.33 SLRCONC
Name:  SLRCONC
Address:  0xF19
Slew Rate Control Register
Bit 7 6 5 4 3 2 1 0
SLRC7 SLRC6 SLRC5 SLRC4 SLRC3 SLRC2 SLRC1 SLRC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – SLRCn Slew Rate Control on Pins Rx<7:0>, respectively
Value Description
1Port pin slew rate is limited
0Port pin slews at maximum rate
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 277
15.5.34 SLRCOND
Name:  SLRCOND
Address:  0xF1E
Slew Rate Control Register
Bit 7 6 5 4 3 2 1 0
SLRD7 SLRD6 SLRD5 SLRD4 SLRD3 SLRD2 SLRD1 SLRD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – SLRDn Slew Rate Control on Pins Rx<7:0>, respectively
Value Description
1Port pin slew rate is limited
0Port pin slews at maximum rate
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 278
15.5.35 SLRCONE
Name:  SLRCONE
Address:  0xF26
Slew Rate Control Register
Bit 7 6 5 4 3 2 1 0
SLRE2 SLRE1 SLRE0
Access R/W R/W R/W
Reset 1 1 1
Bits 0, 1, 2 – SLREn Slew Rate Control on Pins Rx<7:0>, respectively
Value Description
1Port pin slew rate is limited
0Port pin slews at maximum rate
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 279
15.5.36 INLVLA
Name:  INLVLA
Address:  0xF08
Input Level Control Register
Bit 7 6 5 4 3 2 1 0
INLVLA7 INLVLA6 INLVLA5 INLVLA4 INLVLA3 INLVLA2 INLVLA1 INLVLA0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – INLVLAn Input Level Select on Pins Rx<7:0>, respectively
Value Description
1ST input used for port reads and interrupt-on-change
0TTL input used for port reads and interrupt-on-change
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 280
15.5.37 INLVLB
Name:  INLVLB
Address:  0xF10
Input Level Control Register
Bit 7 6 5 4 3 2 1 0
INLVLB7 INLVLB6 INLVLB5 INLVLB4 INLVLB3 INLVLB2 INLVLB1 INLVLB0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – INLVLBn Input Level Select on Pins Rx<7:0>, respectively
Note:  INLVLB2 / INLVLB1: Pins read the I2C ST inputs when MSSP inputs select these pins, and I2C
mode is enabled.
Value Description
1ST input used for port reads and interrupt-on-change
0TTL input used for port reads and interrupt-on-change
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 281
15.5.38 INLVLC
Name:  INLVLC
Address:  0xF18
Input Level Control Register
Bit 7 6 5 4 3 2 1 0
INLVLC7 INLVLC6 INLVLC5 INLVLC4 INLVLC3 INLVLC2 INLVLC1 INLVLC0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – INLVLCn Input Level Select on Pins Rx<7:0>, respectively
Note:  INLVLC4 / INLVLC3: Pins read the I2C ST inputs when MSSP inputs select these pins, and I2C
mode is enabled.
Value Description
1ST input used for port reads and interrupt-on-change
0TTL input used for port reads and interrupt-on-change
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 282
15.5.39 INLVLD
Name:  INLVLD
Address:  0xF1D
Input Level Control Register
Bit 7 6 5 4 3 2 1 0
INLVLD7 INLVLD6 INLVLD5 INLVLD4 INLVLD3 INLVLD2 INLVLD1 INLVLD0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 0, 1, 2, 3, 4, 5, 6, 7 – INLVLDn Input Level Select on Pins Rx<7:0>, respectively
Value Description
1ST input used for port reads and interrupt-on-change
0TTL input used for port reads and interrupt-on-change
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 283
15.5.40 INLVLE
Name:  INLVLE
Address:  0xF25
Input Level Control Register
Bit 7 6 5 4 3 2 1 0
INLVLE3 INLVLE2 INLVLE1 INLVLE0
Access R/W R/W R/W R/W
Reset 1 1 1 1
Bits 0, 1, 2, 3 – INLVLEn Input Level Select on Pins Rx<3:0>, respectively
Note:  28-pin package only has INLVLE3 in this register.
Value Description
1ST input used for port reads and interrupt-on-change
0TTL input used for port reads and interrupt-on-change
PIC18F26/45/46Q10
I/O Ports
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 284
16. Interrupt-on-Change
16.1 Features
Interrupt-on-change Enable (Master Switch)
Individual Pin Configuration
Rising and Falling Edge Detection
Individual Pin Interrupt Flags
16.2 Overview
All the pins of PORTA, PORTB, PORTC, and pin RE3 of PORTE can be configured to operate as
Interrupt-on-Change (IOC) pins on PIC18F26/45/46Q10 family devices. An interrupt can be generated by
detecting a signal that has either a rising edge or a falling edge. Any individual port pin, or combination of
port pins, can be configured to generate an interrupt.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 285
16.3 Block Diagram
Figure 16-1. Interrupt-on-Change Block Diagram (PORTA Example)
IOCANx
IOCAPx
Q2
Q4Q1
data bus =
0 or 1
write IOCAFx
IOCIE
to data bus
IOCAFx
edge
detect
IOC interrupt
to CPU core
from all other
IOCnFx individual
pin detectors
D Q
S
D Q
R
D Q
R
RAx
Q1
Q2
Q3
Q4
Q4Q1
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q4Q1 Q4Q1Q4Q1
FOSC
Rev. 10-000 037A
6/2/201 4
16.4 Enabling the Module
To allow individual port pins to generate an interrupt, the IOCIE bit of the PIE0 register must be set. If the
IOCIE bit is disabled, the edge detection on the pin will still occur, but an interrupt will not be generated.
Related Links
14.13.10 PIE0
16.5 Individual Pin Configuration
For each port pin, a rising edge detector and a falling edge detector are present. To enable a pin to detect
a rising edge, the associated bit of the IOCxP register is set. To enable a pin to detect a falling edge, the
associated bit of the IOCxN register is set.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 286
A pin can be configured to detect rising and falling edges simultaneously by setting both associated bits
of the IOCxP and IOCxN registers, respectively.
16.6 Interrupt Flags
The IOCAFx, IOCBFx, IOCCFx and IOCEF3 bits located in the IOCAF, IOCBF, IOCCF and IOCEF
registers respectively, are status flags that correspond to the interrupt-on-change pins of the associated
port. If an expected edge is detected on an appropriately enabled pin, then the status flag for that pin will
be set, and an interrupt will be generated if the IOCIE bit is set. The IOCIF bit of the PIR0 register reflects
the status of all IOCAFx, IOCBFx, IOCCFx and IOCEF3 bits.
Related Links
14.13.2 PIR0
16.7 Clearing Interrupt Flags
The individual status flags, (IOCAFx, IOCBFx, IOCCFx and IOCEF3) bits, can be cleared by resetting
them to zero. If another edge is detected during this clearing operation, the associated status flag will be
set at the end of the sequence, regardless of the value actually being written.
In order to ensure that no detected edge is lost while clearing flags, only AND operations masking out
known changed bits should be performed. The following sequence is an example of what should be
performed.
Example 16-1. Clearing Interrupt Flags
(PORTA Example)
MOVLW 0xff
XORWF IOCAF, W
ANDWF IOCAF, F
16.8 Operation in Sleep
The interrupt-on-change interrupt sequence will wake the device from Sleep mode, if the IOCIE bit is set.
If an edge is detected while in Sleep mode, the IOCxF register will be updated prior to the first instruction
executed out of Sleep.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 287
16.9 Register Summary - Interrupt-on-Change
Address Name Bit Pos.
0x0F05 IOCAF 7:0 IOCAF7 IOCAF6 IOCAF5 IOCAF4 IOCAF3 IOCAF2 IOCAF1 IOCAF0
0x0F06 IOCAN 7:0 IOCAN7 IOCAN6 IOCAN5 IOCAN4 IOCAN3 IOCAN2 IOCAN1 IOCAN0
0x0F07 IOCAP 7:0 IOCAP7 IOCAP6 IOCAP5 IOCAP4 IOCAP3 IOCAP2 IOCAP1 IOCAP0
0x0F08
...
0x0F0C
Reserved
0x0F0D IOCBF 7:0 IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0
0x0F0E IOCBN 7:0 IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0
0x0F0F IOCBP 7:0 IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0
0x0F10
...
0x0F14
Reserved
0x0F15 IOCCF 7:0 IOCCF7 IOCCF6 IOCCF5 IOCCF4 IOCCF3 IOCCF2 IOCCF1 IOCCF0
0x0F16 IOCCN 7:0 IOCCN7 IOCCN6 IOCCN5 IOCCN4 IOCCN3 IOCCN2 IOCCN1 IOCCN0
0x0F17 IOCCP 7:0 IOCCP7 IOCCP6 IOCCP5 IOCCP4 IOCCP3 IOCCP2 IOCCP1 IOCCP0
0x0F18
...
0x0F21
Reserved
0x0F22 IOCEF 7:0 IOCEF3
0x0F23 IOCEN 7:0 IOCEN3
0x0F24 IOCEP 7:0 IOCEP3
16.10 Register Definitions: Interrupt-on-Change Control
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 288
16.10.1 IOCAF
Name:  IOCAF
Address:  0xF05
PORTA Interrupt-on-Change Flag Register Example
Bit 7 6 5 4 3 2 1 0
IOCAF7 IOCAF6 IOCAF5 IOCAF4 IOCAF3 IOCAF2 IOCAF1 IOCAF0
Access R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCAFn Interrupt-on-Change Flag bits
Value Condition Description
1IOCAP[n]=1A positive edge was detected on the RA[n] pin
1IOCAN[n]=1A negative edge was detected on the RA[n] pin
0IOCAP[n]=x and
IOCAN[n]=x
No change was detected, or the user cleared the detected change
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 289
16.10.2 IOCBF
Name:  IOCBF
Address:  0xF0D
PORTB Interrupt-on-Change Flag Register Example
Bit 7 6 5 4 3 2 1 0
IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0
Access R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCBFn Interrupt-on-Change Flag bits
Value Condition Description
1IOCBP[n]=1A positive edge was detected on the RB[n] pin
1IOCBN[n]=1A negative edge was detected on the RB[n] pin
0IOCBP[n]=x and
IOCBN[n]=x
No change was detected, or the user cleared the detected change
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 290
16.10.3 IOCCF
Name:  IOCCF
Address:  0xF15
PORTC Interrupt-on-Change Flag Register
Bit 7 6 5 4 3 2 1 0
IOCCF7 IOCCF6 IOCCF5 IOCCF4 IOCCF3 IOCCF2 IOCCF1 IOCCF0
Access R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS R/W/HS
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCCFn Interrupt-on-Change Flag bits
Value Condition Description
1IOCCP[n]=1A positive edge was detected on the RC[n] pin
1IOCCN[n]=1A negative edge was detected on the RC[n] pin
0IOCCP[n]=x and
IOCCN[n]=x
No change was detected, or the user cleared the detected
change
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 291
16.10.4 IOCEF
Name:  IOCEF
Address:  0xF22
PORTE Interrupt-on-Change Flag Register
Bit 7 6 5 4 3 2 1 0
IOCEF3
Access R/W/HS
Reset 0
Bit 3 – IOCEF3  PORTE Interrupt-on-Change Flag bits(1)
Value Condition Description
1IOCEP[n]=1A positive edge was detected on the RE[n] pin
1IOCEN[n]=1A negative edge was detected on the RE[n] pin
0IOCEP[n]=x and
IOCEN[n]=x
No change was detected, or the user cleared the detected change
Note: 
1. If MCLRE = 1 or LVP = 1, RE3 port functionality is disabled and IOC on RE3 is not available.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 292
16.10.5 IOCAN
Name:  IOCAN
Address:  0xF06
Interrupt-on-Change Negative Edge Register Example
Bit 7 6 5 4 3 2 1 0
IOCAN7 IOCAN6 IOCAN5 IOCAN4 IOCAN3 IOCAN2 IOCAN1 IOCAN0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCANn Interrupt-on-Change Negative Edge Enable bits
Value Description
1Interrupt-on-Change enabled on the IOCA pin for a negative-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 293
16.10.6 IOCBN
Name:  IOCBN
Address:  0xF0E
Interrupt-on-Change Negative Edge Register Example
Bit 7 6 5 4 3 2 1 0
IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCBNn Interrupt-on-Change Negative Edge Enable bits
Value Description
1Interrupt-on-Change enabled on the IOCA pin for a negative-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 294
16.10.7 IOCCN
Name:  IOCCN
Address:  0xF16
Interrupt-on-Change Negative Edge Register Example
Bit 7 6 5 4 3 2 1 0
IOCCN7 IOCCN6 IOCCN5 IOCCN4 IOCCN3 IOCCN2 IOCCN1 IOCCN0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCCNn Interrupt-on-Change Negative Edge Enable bits
Value Description
1Interrupt-on-Change enabled on the IOCA pin for a negative-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 295
16.10.8 IOCEN
Name:  IOCEN
Address:  0xF23
Interrupt-on-Change Negative Edge Register Example
Bit 7 6 5 4 3 2 1 0
IOCEN3
Access R/W
Reset 0
Bit 3 – IOCEN3  Interrupt-on-Change Negative Edge Enable bits(1)
Value Description
1Interrupt-on-Change enabled on the IOCA pin for a negative-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin
Note: 
1. If MCLRE = 1 or LVP = 1, RE3 port functionality is disabled and IOC on RE3 is not available.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 296
16.10.9 IOCAP
Name:  IOCAP
Address:  0xF07
Interrupt-on-Change Positive Edge Register
Bit 7 6 5 4 3 2 1 0
IOCAP7 IOCAP6 IOCAP5 IOCAP4 IOCAP3 IOCAP2 IOCAP1 IOCAP0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCAPn Interrupt-on-Change Positive Edge Enable bits
Value Description
1Interrupt-on-Change enabled on the IOCA pin for a positive-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 297
16.10.10 IOCBP
Name:  IOCBP
Address:  0xF0F
Interrupt-on-Change Positive Edge Register
Bit 7 6 5 4 3 2 1 0
IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCBPn Interrupt-on-Change Positive Edge Enable bits
Value Description
1Interrupt-on-Change enabled on the IOCB pin for a positive-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 298
16.10.11 IOCCP
Name:  IOCCP
Address:  0xF17
Interrupt-on-Change Positive Edge Register
Bit 7 6 5 4 3 2 1 0
IOCCP7 IOCCP6 IOCCP5 IOCCP4 IOCCP3 IOCCP2 IOCCP1 IOCCP0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – IOCCPn Interrupt-on-Change Positive Edge Enable bits
Value Description
1Interrupt-on-Change enabled on the IOCC pin for a positive-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 299
16.10.12 IOCEP
Name:  IOCEP
Address:  0xF24
Interrupt-on-Change Positive Edge Register
Bit 7 6 5 4 3 2 1 0
IOCEP3
Access R/W
Reset 0
Bit 3 – IOCEP3  Interrupt-on-Change Positive Edge Enable bit(1)
Value Description
1Interrupt-on-Change enabled on the IOCE pin for a positive-going edge. Associated Status
bit and interrupt flag will be set upon detecting an edge.
0Interrupt-on-Change disabled for the associated pin.
Note: 
1. If MCLRE = 1 or LVP = 1, RE3 port functionality is disabled and IOC on RE3 is not available.
PIC18F26/45/46Q10
Interrupt-on-Change
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 300
17. (PPS) Peripheral Pin Select Module
The Peripheral Pin Select (PPS) module connects peripheral inputs and outputs to the device I/O pins.
Only digital signals are included in the selections. All analog inputs and outputs remain fixed to their
assigned pins. Input and output selections are independent as shown in the figure below.
The peripheral input is selected with the peripheral 17.9.1 xxxPPS register, and the peripheral output is
selected with the PORT 17.9.2 RxyPPS register . For example, to select PORTC<7> as the EUSART RX
input, set RXxPPS to 0x17 as shown in the input table, and to select PORTC<6> as the EUSART TX
output set RC6PPS to 0x09 as shown in the output table.
Figure 17-1. Simplified PPS Block Diagram
Rev. 10-000 262B
2/22/201 7
xyzPPS
RC7
abcPPS
RA0
Peripheral xyz
Peripheral abc
RA0PPS
RxyPPS
RC7PPS
RA0
Rxy
RC7
17.1 PPS Inputs
Each peripheral has an xxxPPS register with which the input pin to the peripheral is selected. Not all ports
are available for input as shown in the following table.
Multiple peripherals can operate from the same source simultaneously. Port reads always return the pin
level regardless of peripheral PPS selection. If a pin also has analog functions associated, the ANSEL bit
for that pin must be cleared to enable the digital input buffer.
Important:  The notation “xxx” in the generic register name is a place holder for the peripheral
identifier. For example, xxx = INT for the INTPPS register.
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 301
Table 17-1. PPS Input Selection Register Details
Peripheral PPS Input
Register
Default Pin
Selection
at POR
Register
Reset
Value
at POR
PORT From Which Input Is
Available
28-Pin Devices 40-Pin Devices
Interrupt 0 INT0PPS RB0 0x08 A B A B
Interrupt 1 INT1PPS RB1 0x09 A B A B
Interrupt 2 INT2PPS RB2 0x0A A B A B
Timer0 Clock T0CKIPPS RA4 0x04 A B A B
Timer1 Clock T1CKIPPS RC0 0x10 A C A C
Timer1 Gate T1GPPS RB5 0x0D B C B C
Timer3 Clock T3CKIPPS RC0 0x10 B C B C
Timer3 Gate T3GPPS RC0 0x10 A C A C
Timer5 Clock T5CKIPPS RC2 0x12 A C A C
Timer5 Gate T5GPPS RB4 0x0C B C B D
Timer2 Clock T2INPPS RC3 0x13 A C A C
Timer4 Clock T4INPPS RC5 0x15 B C B C
Timer6 Clock T6INPPS RB7 0x0F B C B D
ADC
Conversion
Trigger
ADACTPPS RB4 0x0C B C B D
CCP1 CCP1PPS RC2 0x12 B C B C
CCP2 CCP2PPS RC1 0x11 B C B C
CWG CWG1PPS RB0 0x08 B C B D
DSM Carrier
Low
MDCARLPPS RA3 0x03 A C A D
DSM Carrier
High
MDCARHPPS RA4 0x04 A C A D
DSM Source MDSRCPPS RA5 0x05 A C A D
EUSART1
Receive
RX1PPS RC7 0x17 B C B C
EUSART1
Clock
CK1PPS RC6 0x16 B C B C
EUSART2
Receive
RX2PPS RB7 0x0F B C B D
EUSART2
Clock
CK2PPS RB6 0x0E B C B D
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 302
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Peripheral PPS Input
Register
Default Pin
Selection
at POR
Register
Reset
Value
at POR
PORT From Which Input Is
Available
28-Pin Devices 40-Pin Devices
MSSP1 Clock SSP1CLKPPS RC3 0x13 B C B C
MSSP1 Data SSP1DATPPS RC4 0x14 B C B C
MSSP1 Slave
Select
SSP1SSPPS RA5 0x05 A C A D
MSSP2 Clock SSP2CLKPPS RB1 0x09 B C B D
MSSP2 Data SSP2DATPPS RB2 0x0A B C B D
MSSP2 Slave
Select
SSP2SSPPS RB0 0x08 B C B D
CLCIN0 CLCIN0PPS RA0 0x00 A C A C
CLCIN1 CLCIN1PPS RA1 0x01 A C A C
CLCIN2 CLCIN2PPS RB6 0x0E B C B D
CLCIN3 CLCIN3PPS RB7 0x0F B C B D
CLCIN4 CLCIN4PPS RA0 0x00 A C A C
CLCIN5 CLCIN5PPS RA1 0x01 A C A C
CLCIN6 CLCIN6PPS RB6 0x0E B C B D
CLCIN7 CLCIN7PPS RB7 0x0F B C B D
17.2 PPS Outputs
Each I/O pin has an RxyPPS register with which the pin output source is selected. With few exceptions,
the port TRIS control associated with that pin retains control over the pin output driver. Peripherals that
control the pin output driver as part of the peripheral operation will override the TRIS control as needed.
These peripherals include:
EUSART (synchronous operation)
MSSP (I2C)
Although every pin has its own RxyPPS peripheral selection register, the selections are identical for every
pin as shown in the following table.
Important:  The notation “Rxy” is a place holder for the pin identifier. The 'x' holds the place of
the PORT letter and the 'y' holds the place of the bit number. For example, Rxy = RA0 for the
RA0PPS register.
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 303
Table 17-2. Peripheral PPS Output Selection Codes
RxyPPS Pin Rxy Output Source
PORT To Which Output Can Be Directed
28-Pin Devices 40-Pin Devices
0x1F CLC8OUT B C B D
0x1E CLC7OUT B C B D
0x1D CLC6OUT A C A C
0x1C CLC5OUT A C A C
0x1B CLC4OUT B C B D
0x1A CLC3OUT B C B D
0x19 CLC2OUT A C A C
0x18 CLC1OUT A C A C
0x17 ADGRDB A C A C
0x16 ADGRDA A C A C
0x15 DSM A C A D
0x14 CLKR B C B C
0x13 TMR0 B C B C
0x12 MSSP2 (SDO/SDA) B C B D
0x11 MSSP2 (SCK/SCL) B C B D
0x10 MSSP1 (SDO/SDA) B C B C
0x0F MSSP1 (SCK/SCL) B C B C
0x0E CMP2 A C A E
0x0D CMP1 A C A D
0x0C EUSART2 (DT) B C B D
0x0B EUSART2 (TX/CK) B C B D
0x0A EUSART1 (DT) B C B C
0x09 EUSART1 (TX/CK) B C B C
0x08 PWM4 A C A C
0x07 PWM3 A C A D
0x06 CCP2 B C B C
0x05 CCP1 B C B C
0x04 CWG1D B C B D
0x03 CWG1C B C B D
0x02 CWG1B B C B D
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...........continued
RxyPPS Pin Rxy Output Source
PORT To Which Output Can Be Directed
28-Pin Devices 40-Pin Devices
0x01 CWG1A B C B C
0x00 LATxy A B C A B C D E
17.3 Bidirectional Pins
PPS selections for peripherals with bidirectional signals on a single pin must be made so that the PPS
input and PPS output select the same pin. Peripherals that have bidirectional signals include:
EUSART (DT/RXxPPS and TX/CKxPPS pins for synchronous operation)
MSSP (I2C SDA/SSPxDATPPS and SCL/SSPxCLKPPS)
Important:  The I2C default inputs, and a limited number of other alternate pins, are I2C and
SMBus compatible. Clock and data signals can be routed to any pin, however pins without I2C
compatibility will operate at standard TTL/ST logic levels as selected by the INLVL register. See
the INLVL register for each port to determine which pins are I2C and SMBus compatible.
17.4 PPS Lock
The PPS includes a mode in which all input and output selections can be locked to prevent inadvertent
changes. PPS selections are locked by setting the PPSLOCKED bit of the PPSLOCK register. Setting
and clearing this bit requires a special sequence as an extra precaution against inadvertent changes.
Examples of setting and clearing the PPSLOCKED bit are shown in the following examples.
Example 17-1. PPS Lock Sequence
; Disable interrupts:
BCF INTCON,GIE
; Bank to PPSLOCK register
BANKSEL PPSLOCK
MOVLW 55h
; Required sequence, next 4 instructions
MOVWF PPSLOCK
MOVLW AAh
MOVWF PPSLOCK
; Set PPSLOCKED bit to disable writes
; Only a BSF instruction will work
BSF PPSLOCK,PPSLOCKED
; Enable Interrupts
BSF INTCON,GIE
Example 17-2. PPS Unlock Sequence
; Disable interrupts:
BCF INTCON,GIE
; Bank to PPSLOCK register
BANKSEL PPSLOCK
MOVLW 55h
; Required sequence, next 4 instructions
MOVWF PPSLOCK
MOVLW AAh
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 305
MOVWF PPSLOCK
; Clear PPSLOCKED bit to enable writes
; Only a BCF instruction will work
BCF PPSLOCK,PPSLOCKED
; Enable Interrupts
BSF INTCON,GIE
17.5 PPS One-Way Lock
Using the PPS1WAY Configuration bit, the PPS settings can be locked in. When this bit is set, the
PPSLOCKED bit can only be cleared and set one time after a device Reset. This allows for clearing the
PPSLOCKED bit so that the input and output selections can be made during initialization. When the
PPSLOCKED bit is set after all selections have been made, it will remain set and cannot be cleared until
after the next device Reset event.
17.6 Operation During Sleep
PPS input and output selections are unaffected by Sleep.
17.7 Effects of a Reset
A device Power-on-Reset (POR) clears all PPS input and output selections to their default values. All
other Resets leave the selections unchanged. Default input selections are shown in the input selection
register table. The PPS one-way is also removed.
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 306
17.8 Register Summary - PPS
Address Name Bit Pos.
0x0E1F CLCIN0PPS 7:0 PORT[1:0] PIN[2:0]
0x0E20 CLCIN1PPS 7:0 PORT[1:0] PIN[2:0]
0x0E21 CLCIN2PPS 7:0 PORT[1:0] PIN[2:0]
0x0E22 CLCIN3PPS 7:0 PORT[1:0] PIN[2:0]
0x0E23 CLCIN4PPS 7:0 PORT[1:0] PIN[2:0]
0x0E24 CLCIN5PPS 7:0 PORT[1:0] PIN[2:0]
0x0E25 CLCIN6PPS 7:0 PORT[1:0] PIN[2:0]
0x0E26 CLCIN7PPS 7:0 PORT[1:0] PIN[2:0]
0x0E27
...
0x0E87
Reserved
0x0E88 RX2PPS 7:0 PORT[1:0] PIN[2:0]
0x0E89 CK2PPS 7:0 PORT[1:0] PIN[2:0]
0x0E8A SSP2CLKPPS 7:0 PORT[1:0] PIN[2:0]
0x0E8B SSP2DATPPS 7:0 PORT[1:0] PIN[2:0]
0x0E8C SSP2SSPPS 7:0 PORT[1:0] PIN[2:0]
0x0E8D
...
0x0E9A
Reserved
0x0E9B PPSLOCK 7:0 PPSLOCKED
0x0E9C INT0PPS 7:0 PORT PIN[2:0]
0x0E9D INT1PPS 7:0 PORT PIN[2:0]
0x0E9E INT2PPS 7:0 PORT PIN[2:0]
0x0E9F T0CKIPPS 7:0 PORT PIN[2:0]
0x0EA0 T1CKIPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA1 T1GPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA2 T3CKIPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA3 T3GPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA4 T5CKIPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA5 T5GPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA6 T2INPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA7 T4INPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA8 T6INPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA9 ADACTPPS 7:0 PORT[1:0] PIN[2:0]
0x0EAA CCP1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EAB CCP2PPS 7:0 PORT[1:0] PIN[2:0]
0x0EAC CWG1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EAD MDCARLPPS 7:0 PORT[1:0] PIN[2:0]
0x0EAE MDCARHPPS 7:0 PORT[1:0] PIN[2:0]
0x0EAF MDSRCPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB0 RX1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EB1 CK1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EB2 SSP1CLKPPS 7:0 PORT[1:0] PIN[2:0]
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...........continued
Address Name Bit Pos.
0x0EB3 SSP1DATPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB4 SSP1SSPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB5
...
0x0EE1
Reserved
0x0EE2 RA0PPS 7:0 PPS[4:0]
0x0EE3 RA1PPS 7:0 PPS[4:0]
0x0EE4 RA2PPS 7:0 PPS[4:0]
0x0EE5 RA3PPS 7:0 PPS[4:0]
0x0EE6 RA4PPS 7:0 PPS[4:0]
0x0EE7 RA5PPS 7:0 PPS[4:0]
0x0EE8 RA6PPS 7:0 PPS[4:0]
0x0EE9 RA7PPS 7:0 PPS[4:0]
0x0EEA RB0PPS 7:0 PPS[4:0]
0x0EEB RB1PPS 7:0 PPS[4:0]
0x0EEC RB2PPS 7:0 PPS[4:0]
0x0EED RB3PPS 7:0 PPS[4:0]
0x0EEE RB4PPS 7:0 PPS[4:0]
0x0EEF RB5PPS 7:0 PPS[4:0]
0x0EF0 RB6PPS 7:0 PPS[4:0]
0x0EF1 RB7PPS 7:0 PPS[4:0]
0x0EF2 RC0PPS 7:0 PPS[4:0]
0x0EF3 RC1PPS 7:0 PPS[4:0]
0x0EF4 RC2PPS 7:0 PPS[4:0]
0x0EF5 RC3PPS 7:0 PPS[4:0]
0x0EF6 RC4PPS 7:0 PPS[4:0]
0x0EF7 RC5PPS 7:0 PPS[4:0]
0x0EF8 RC6PPS 7:0 PPS[4:0]
0x0EF9 RC7PPS 7:0 PPS[4:0]
0x0EFA RD0PPS 7:0 PPS[4:0]
0x0EFB RD1PPS 7:0 PPS[4:0]
0x0EFC RD2PPS 7:0 PPS[4:0]
0x0EFD RD3PPS 7:0 PPS[4:0]
0x0EFE RD4PPS 7:0 PPS[4:0]
0x0EFF RD5PPS 7:0 PPS[4:0]
0x0F00 RD6PPS 7:0 PPS[4:0]
0x0F01 RD7PPS 7:0 PPS[4:0]
0x0F02 RE0PPS 7:0 PPS[4:0]
0x0F03 RE1PPS 7:0 PPS[4:0]
0x0F04 RE2PPS 7:0 PPS[4:0]
17.9 Register Definitions: PPS Input and Output Selection
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 308
17.9.1 Peripheral xxx Input Selection
Name:  xxxPPS
Important:  The Reset value of this register is determined by the device default for each
peripheral.
Refer to the input selection table for a list of available ports and default pin locations.
Bit 7 6 5 4 3 2 1 0
PORT[1:0] PIN[2:0]
Access R/W R/W R/W R/W R/W
Reset g g g g g
Bits 4:3 – PORT[1:0] Peripheral xxx Input PORT Selection bits
See the input selection table for a list of available ports and default pin locations.
Value Description
11 PORTD
10 PORTC
01 PORTB
00 PORTA
Bits 2:0 – PIN[2:0] Peripheral xxx Input Pin Selection bits
Value Description
111 Peripheral input is from PORTx Pin 7 (Rx7)
110 Peripheral input is from PORTx Pin 6 (Rx6)
101 Peripheral input is from PORTx Pin 5 (Rx5)
100 Peripheral input is from PORTx Pin 4 (Rx4)
011 Peripheral input is from PORTx Pin 3 (Rx3)
010 Peripheral input is from PORTx Pin 2 (Rx2)
001 Peripheral input is from PORTx Pin 1 (Rx1)
000 Peripheral input is from PORTx Pin 0 (Rx0)
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 309
17.9.2 Pin Rxy Output Source Selection Register
Name:  RxyPPS
Important:  See 17.8 Register Summary - PPS for the address offset of each individual
register.
Bit 7 6 5 4 3 2 1 0
RxyPPS[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – RxyPPS[4:0] Pin Rxy Output Source Selection bits
See output source selection table for source codes.
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 310
17.9.3 PPS Lock Register
Name:  PPSLOCK
Address:  0xE9B
Bit 7 6 5 4 3 2 1 0
PPSLOCKED
Access R/W
Reset 0
Bit 0 – PPSLOCKED PPS Locked bit
Value Description
1PPS is locked. PPS selections can not be changed.
0PPS is not locked. PPS selections can be changed.
PIC18F26/45/46Q10
(PPS) Peripheral Pin Select Module
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18. Timer0 Module
Timer0 module has the following features:
8-Bit B\Timer with Programmable Period
16-Bit Timer
Selectable Clock Sources
Synchronous and Asynchronous Operation
Programmable Prescaler and Postscaler
Interrupt on Match or Overflow
Output on I/O Pin (via PPS) or to Other Peripherals
Operation During Sleep
Figure 18-1. Timer0 Block Diagram
Rev. 10-000017I
2/8/2018
T0CKIPPS
See T0CON1
Register
T0CS
T0CKPS
Prescaler
FOSC/4
T0ASYNCT016BIT
T0OUTPS T0IF
T0_out
Peripherals
TMR0
1
0Postscaler
TMR0L
COMPARATOR
TMR0 High
Byte
TMR0H
T0_match
Clear
Latch
Enable
8-bit TMR0 Body Diagram (T016BIT = 0)
TMR0L
TMR0H
Internal Data Bus
16-bit TMR0 Body Diagram (T016BIT = 1)
SYNC IN OUT
TMR0
body
Q
Q
D
CK
PPS
RxyPPS
R
IN
OUT
TMR0 High
Byte
IN OUT
Read TMR0L
Write TMR0L
8
8
8
8
8
PPS
PIC18F26/45/46Q10
Timer0 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 312
18.1 Timer0 Operation
Timer0 can operate as either an 8-bit or 16-bit timer. The mode is selected with the T016BIT bit.
18.1.1 8-bit Mode
In this mode Timer0 increments on the rising edge of the selected clock source. A prescaler on the clock
input gives several prescale options (see prescaler control bits, T0CKPS).
In this mode as shown in Figure 18-1, a buffered version of TMR0H is maintained. This is compared with
the value of TMR0L on each cycle of the selected clock source. When the two values match, the following
events occur:
TMR0L is reset
The contents of TMR0H are copied to the TMR0H buffer for next comparison
18.1.2 16-Bit Mode
In this mode Timer0 increments on the rising edge of the selected clock source. A prescaler on the clock
input gives several prescale options (see prescaler control bits, T0CKPS).
In this mode TMR0H:TMR0L form the 16-bit timer value. As shown in Figure 18-1, read and write of the
TMR0H register are buffered. TMR0H register is updated with the contents of the high byte of Timer0
during a read of TMR0L register. Similarly, a write to the high byte of Timer0 takes place through the
TMR0H buffer register. The high byte is updated with the contents of TMR0H register when a write occurs
to TMR0L register. This allows all 16 bits of Timer0 to be read and written at the same time.
Timer0 rolls over to 0x0000 on incrementing past 0xFFFF. This makes the timer free-running. TMR0L/H
registers cannot be reloaded in this mode once started.
18.2 Clock Selection
Timer0 has several options for clock source selections, option to operate synchronously/asynchronously
and a programmable prescaler.
18.2.1 Clock Source Selection
The T0CS bits are used to select the clock source for Timer0. The possible clock sources are listed in the
table below.
Table 18-1. Timer 0 Clock Source Selections
T0CS Clock Source
111 CLC1_out
110 MFINTOSC (500 kHz)
101 SOSC
100 LFINTOSC
011 HFINTOSC
010 FOSC/4
001 Pin selected by T0CKIPPS (Inverted)
000 Pin selected by T0CKIPPS (Non-inverted)
PIC18F26/45/46Q10
Timer0 Module
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18.2.2 Synchronous Mode
When the T0ASYNC bit is clear, Timer0 clock is synchronized to the system clock (FOSC/4). When
operating in Synchronous mode, Timer0 clock frequency cannot exceed FOSC/4. During Sleep mode
system clock is not available and Timer0 cannot operate.
18.2.3 Asynchronous Mode
When the T0ASYNC bit is set, Timer0 increments with each rising edge of the input source (or output of
the prescaler, if used). Asynchronous mode allows Timer0 to continue operation during Sleep mode
provided the selected clock source is available.
18.2.4 Programmable Prescaler
Timer0 has 16 programmable input prescaler options ranging from 1:1 to 1:32768. The prescaler values
are selected using the T0CKPS bits.
The prescaler counter is not directly readable or writable. The prescaler counter is cleared on the
following events:
A write to the TMR0L register
A write to either the T0CON0 or T0CON1 registers
Any device Reset
Related Links
8. Resets
18.3 Timer0 Output and Interrupt
18.3.1 Programmable Postscaler
Timer0 has 16 programmable output postscaler options ranging from 1:1 to 1:16. The postscaler values
are selected using the T0OUTPS bits. The postscaler divides the output of Timer0 by the selected ratio.
The postscaler counter is not directly readable or writable. The postscaler counter is cleared on the
following events:
A write to the TMR0L register
A write to either the T0CON0 or T0CON1 registers
Any device Reset
18.3.2 Timer0 Output
TMR0_out is the output of the postscaler. TMR0_out toggles on every match between TMR0L and
TMR0H in 8-bit mode, or when TMR0H:TMR0L rolls over in 16-bit mode. If the output postscaler is used,
the output is scaled by the ratio selected.
The Timer0 output can be routed to an I/O pin via the RxyPPS output selection register. The Timer0
output can be monitored through software via the T0OUT output bit.
Related Links
17.2 PPS Outputs
18.3.3 Timer0 Interrupt
The Timer0 Interrupt Flag bit (TMR0IF) is set when the TMR0_out toggles. If the Timer0 interrupt is
enabled (TMR0IE), the CPU will be interrupted when the TMR0IF bit is set.
PIC18F26/45/46Q10
Timer0 Module
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When the postscaler bits (T0OUTPS) are set to 1:1 operation (no division), the T0IF flag bit will be set
with every TMR0 match or rollover. In general, the TMR0IF flag bit will be set every T0OUTPS +1
matches or rollovers.
18.3.4 Timer0 Example
Timer0 Configuration:
Timer0 mode = 16-bit
Clock Source = FOSC/4 (250 kHz)
Synchronous operation
Prescaler = 1:1
Postscaler = 1:2 (T0OUTPS = 1)
In this case the TMR0_out toggles every two rollovers of TMR0H:TMR0L. i.e.,
(0xFFFF)*2*(1/250kHz) = 524.28 ms
18.4 Operation During Sleep
When operating synchronously, Timer0 will halt when the device enters Sleep mode.
When operating asynchronously and selected clock source is active, Timer0 will continue to increment
and wake the device from Sleep mode if Timer0 interrupt is enabled.
PIC18F26/45/46Q10
Timer0 Module
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18.5 Register Summary - Timer0
Address Name Bit Pos.
0x0FD2 TMR0L 7:0 TMR0L[7:0]
0x0FD3 TMR0H 7:0 TMR0H[7:0]
0x0FD4 T0CON0 7:0 T0EN T0OUT T016BIT T0OUTPS[3:0]
0x0FD5 T0CON1 7:0 T0CS[2:0] T0ASYNC T0CKPS[3:0]
18.6 Register Definitions: Timer0 Control
PIC18F26/45/46Q10
Timer0 Module
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18.6.1 T0CON0
Name:  T0CON0
Address:  0xFD4
Timer0 Control Register 0
Bit 7 6 5 4 3 2 1 0
T0EN T0OUT T016BIT T0OUTPS[3:0]
Access R/W R R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bit 7 – T0EN TMR0 Enable
Value Description
1The module is enabled and operating
0The module is disabled
Bit 5 – T0OUT TMR0 Output
Bit 4 – T016BIT TMR0 Operating as 16-Bit Timer Select
Value Description
1TMR0 is a 16-bit timer
0TMR0 is an 8-bit timer
Bits 3:0 – T0OUTPS[3:0] TMR0 Output Postscaler (Divider) Select
Value Description
1111 1:16 Postscaler
1110 1:15 Postscaler
1101 1:14 Postscaler
1100 1:13 Postscaler
1011 1:12 Postscaler
1010 1:11 Postscaler
1001 1:10 Postscaler
1000 1:9 Postscaler
0111 1:8 Postscaler
0110 1:7 Postscaler
0101 1:6 Postscaler
0100 1:5 Postscaler
0011 1:4 Postscaler
0010 1:3 Postscaler
0001 1:2 Postscaler
0000 1:1 Postscaler
PIC18F26/45/46Q10
Timer0 Module
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18.6.2 T0CON1
Name:  T0CON1
Address:  0xFD5
Timer0 Control Register 1
Bit 7 6 5 4 3 2 1 0
T0CS[2:0] T0ASYNC T0CKPS[3:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:5 – T0CS[2:0] Timer0 Clock Source Select
Refer the clock source selection table
Bit 4 – T0ASYNC TMR0 Input Asynchronization Enable
Value Description
1The input to the TMR0 counter is not synchronized to system clocks
0The input to the TMR0 counter is synchronized to FOSC/4
Bits 3:0 – T0CKPS[3:0] Prescaler Rate Select
Value Description
1111 1:32768
1110 1:16384
1101 1:8192
1100 1:4096
1011 1:2048
1010 1:1024
1001 1:512
1000 1:256
0111 1:128
0110 1:64
0101 1:32
0100 1:16
0011 1:8
0010 1:4
0001 1:2
0000 1:1
PIC18F26/45/46Q10
Timer0 Module
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18.6.3 TMR0H
Name:  TMR0H
Address:  0xFD3
Timer0 Period/Count High Register
Bit 7 6 5 4 3 2 1 0
TMR0H[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – TMR0H[7:0] TMR0 Most Significant Counter
Value Condition Description
0 to
255
T016BIT = 08-bit Timer0 Period Value. TMR0L continues counting from 0 when this value
is reached.
0 to
255
T016BIT = 116-bit Timer0 Most Significant Byte
PIC18F26/45/46Q10
Timer0 Module
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18.6.4 TMR0L
Name:  TMR0L
Address:  0xFD2
Timer0 Period/Count Low Register
Bit 7 6 5 4 3 2 1 0
TMR0L[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – TMR0L[7:0] TMR0 Least Significant Counter
Value Condition Description
0 to
255
T016BIT = 08-bit Timer0 Counter bits
0 to
255
T016BIT = 116-bit Timer0 Least Significant Byte
PIC18F26/45/46Q10
Timer0 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 320
19. Timer1 Module with Gate Control
Timer1 module is a 16-bit timer/counter with the following features:
16-Bit Timer/Counter Register Pair (TMRxH:TMRxL)
Programmable Internal or External Clock Source
2-Bit Prescaler
Optionally Synchronized Comparator Out
Multiple Timer1 Gate (count enable) Sources
Interrupt-on-Overflow
Wake-Up on Overflow (external clock, Asynchronous mode only)
16-Bit Read/Write Operation
Time Base for the Capture/Compare Function with the CCP modules
Special Event Trigger (with CCP)
Selectable Gate Source Polarity
Gate Toggle mode
Gate Single Pulse mode
Gate Value Status
Gate Event Interrupt
Important:  References to module Timer1 apply to all the odd numbered timers on this device.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 321
Figure 19-1. Timer1 Block Diagram
Rev. 10-000018L
6/26/2017
TxGPPS
GSS<4:0>
GPOL
0
1
Single Pulse
Acq. Control
1
0
GSPM
ON
GTM
GE
ON
DQ
EN
TMRxLTMRxH
Tx_overflow
set flag bit
TMRxIF
TMRx(2)
1
0
CS<4:0>
Prescaler
1,2,4,8
SYNC
Sleep
Input
Fosc/2
Internal
Clock
CKPS<1:0>
Synchronized Clock Input
2
det
Synchronize(3)
(1)
D
QCK
R
Q
GGO/DONE
TxCLK
D Q
set bit
TMRxGIF
GVAL
Q1
det
Interrupt
NOTE (5)
Note (4)
To Comparators (6)
00000
00000
5
5
11111
11111
PPS
TxCKIPPS
PPS
Note: 
1. This signal comes from the pin seleted by TxCKIPPS.
2. TMRx register increments on rising edge.
3. Synchronize does not operate while in Sleep.
4. See TMRxCLK for clock source selections.
5. See TMRxGATE for gate source selection.
6. Synchronized comparator output should not be used in conjunction with synchronized input clock.
19.1 Timer1 Operation
The Timer1 module is a 16-bit incrementing counter that is accessed through the TMRxH:TMRxL register
pair. Writes to TMRxH or TMRxL directly update the counter.
When used with an internal clock source, the module is a timer and increments on every instruction cycle.
When used with an external clock source, the module can be used as either a timer or counter and
increments on every selected edge of the external source.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 322
Timer1 is enabled by configuring the ON and GE bits in the TxCON and TxGCON registers, respectively.
The table below displays the Timer1 enable selections.
Table 19-1. Timer1 Enable Selections
ON GE Timer1 Operation
1 1 Count Enabled
1 0 Always On
0 1 Off
0 0 Off
19.2 Clock Source Selection
The CS bits select the clock source for Timer1. These bits allow the selection of several possible
synchronous and asynchronous clock sources. The table below lists the clock source selections.
Table 19-2. Timer Clock Sources
CS
Clock Source
Timer1 Timer3 Timer5
11000-11111 Reserved Reserved Reserved
10111 CLC8_out CLC8_out CLC8_out
10110 CLC7_out CLC7_out CLC7_out
10101 CLC6_out CLC6_out CLC6_out
10100 CLC5_out CLC5_out CLC5_out
10011 CLC4_out CLC4_out CLC4_out
10010 CLC3_out CLC3_out CLC3_out
10001 CLC2_out CLC2_out CLC2_out
10000 CLC1_out CLC1_out CLC1_out
01111-01100 Reserved Reserved Reserved
01011 TMR5 overflow TMR5 overflow Reserved
01010 TMR3 overflow Reserved TMR3 overflow
01001 Reserved TMR1 overflow TMR1 overflow
01000 TMR0 overflow TMR0 overflow TMR0 overflow
00111 CLKREF CLKREF CLKREF
00110 SOSC SOSC SOSC
00101 MFINTOSC (500 kHz) MFINTOSC (500 kHz) MFINTOSC (500 kHz)
00100 LFINTOSC LFINTOSC LFINTOSC
00011 HFINTOSC HFINTOSC HFINTOSC
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 323
...........continued
CS
Clock Source
Timer1 Timer3 Timer5
00010 FOSC FOSC FOSC
00001 FOSC/4 FOSC/4 FOSC/4
00000 T1CKIPPS T3CKIPPS T5CKIPPS
19.2.1 Internal Clock Source
When the internal clock source is selected the TMRxH:TMRxL register pair will increment on multiples of
FOSC as determined by the Timer1 prescaler.
When the FOSC internal clock source is selected, the Timer1 register value will increment by four counts
every instruction clock cycle. Due to this condition, a 2 LSB error in resolution will occur when reading the
Timer1 value. To utilize the full resolution of Timer1, an asynchronous input signal must be used to gate
the Timer1 clock input.
Important:  In Counter mode, a falling edge must be registered by the counter prior to the first
incrementing rising edge after any one or more of the following conditions:
Timer1 enabled after POR
Write to TMRxH or TMRxL
Timer1 is disabled
Timer1 is disabled (TMRxON = 0) when TxCKI is high then Timer1 is enabled (TMRxON =
1) when TxCKI is low. Refer to the figure below.
Figure 19-2. Timer1 Incrementing Edge
TxCKI = 1
when TMRx
Enabled
TxCKI = 0
when TMRx
Enabled
Rev. 30-000136A
5/24/2017
Note: 
1. Arrows indicate counter increments.
2. In Counter mode, a falling edge must be registered by the counter prior to the first incrementing
rising edge of the clock.
19.2.2 External Clock Source
When the external clock source is selected, the Timer1 module may work as a timer or a counter.
When enabled to count, Timer1 is incremented on the rising edge of the external clock input of the
TxCKIPPS pin. This external clock source can be synchronized to the system clock or it can run
asynchronously.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 324
19.3 Timer1 Prescaler
Timer1 has four prescaler options allowing 1, 2, 4 or 8 divisions of the clock input. The CKPS bits control
the prescale counter. The prescale counter is not directly readable or writable; however, the prescaler
counter is cleared upon a write to TMRxH or TMRxL.
19.4 Secondary Oscillator
A secondary low-power 32.768 kHz oscillator circuit is built-in between pins SOSCI (input) and SOSCO
(amplifier output). This internal circuit is to be used in conjunction with an external 32.768 kHz crystal.
The secondary oscillator is not dedicated only to Timer1; it can also be used by other modules.
The oscillator circuit is enabled by setting the SOSCEN bit of the OSCEN register. This can be used as
one of the Timer1 clock sources selected with the CS bits. The oscillator will continue to run during Sleep.
Important:  The oscillator requires a start-up and stabilization time before use. Thus, the
SOSCEN bit of the OSCEN register should be set and a suitable delay observed prior to
enabling Timer1. A software check can be performed to confirm if the secondary oscillator is
enabled and ready to use. This is done by polling the SOR bit of the OSCSTAT.
Related Links
4.2.1.5 Secondary Oscillator
19.5 Timer1 Operation in Asynchronous Counter Mode
When the SYNC control bit is set, the external clock input is not synchronized. The timer increments
asynchronously to the internal phase clocks. If external clock source is selected then the timer will
continue to run during Sleep and can generate an interrupt on overflow, which will wake-up the processor.
However, special precautions in software are needed to read/write the timer (see 19.5.1 Reading and
Writing Timer1 in Asynchronous Counter Mode).
Important:  When switching from synchronous to asynchronous operation, it is possible to skip
an increment. When switching from asynchronous to synchronous operation, it is possible to
produce an additional increment.
19.5.1 Reading and Writing Timer1 in Asynchronous Counter Mode
Reading TMRxH or TMRxL while the timer is running from an external asynchronous clock will ensure a
valid read (taken care of in hardware). However, the user should keep in mind that reading the 16-bit
timer in two 8-bit values itself, poses certain problems, since the timer may overflow between the reads.
For writes, it is recommended that the user simply stop the timer and write the desired values. A write
contention may occur by writing to the timer registers, while the register is incrementing. This may
produce an unpredictable value in the TMRxH:TMRxL register pair.
19.6 Timer1 16-Bit Read/Write Mode
Timer1 can be configured to read and write all 16 bits of data, to and from, the 8-bit TMRxL and TMRxH
registers, simultaneously. The 16-bit read and write operations are enabled by setting the RD16 bit.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 325
To accomplish this function, the TMRxH register value is mapped to a buffer register called the TMRxH
buffer register. While in 16-Bit mode, the TMRxH register is not directly readable or writable and all read
and write operations take place through the use of this TMRxH buffer register.
When a read from the TMRxL register is requested, the value of the TMRxH register is simultaneously
loaded into the TMRxH buffer register. When a read from the TMRxH register is requested, the value is
provided from the TMRxH buffer register instead. This provides the user with the ability to accurately read
all 16 bits of the Timer1 value from a single instance in time. Refer the figure below for more details.
In contrast, when not in 16-Bit mode, the user must read each register separately and determine if the
values have become invalid due to a rollover that may have occurred between the read operations.
When a write request of the TMRxL register is requested, the TMRxH buffer register is simultaneously
updated with the contents of the TMRxH register. The value of TMRxH must be preloaded into the
TMRxH buffer register prior to the write request for the TMRxL register. This provides the user with the
ability to write all 16 bits to the TMRxL:TMRxH register pair at the same time.
Any requests to write to the TMRxH directly does not clear the Timer1 prescaler value. The prescaler
value is only cleared through write requests to the TMRxL register.
Figure 19-3. Timer1 16-Bit Read/Write Mode Block Diagram
TMR1L
Internal Data Bus
8
Set
TMR1IF
on Overflow
TMR1
TMR1H
High Byte
88
8
Read TMR1L
Write TMR1L
8
From
Timer1
Circuitry
Rev. 30-000135A
5/24/2017
19.7 Timer1 Gate
Timer1 can be configured to count freely or the count can be enabled and disabled using Timer1 gate
circuitry. This is also referred to as Timer1 gate enable.
Timer1 gate can also be driven by multiple selectable sources.
19.7.1 Timer1 Gate Enable
The Timer1 Gate Enable mode is enabled by setting the GE bit. The polarity of the Timer1 Gate Enable
mode is configured using the GPOL bit.
When Timer1 Gate Enable mode is enabled, Timer1 will increment on the rising edge of the Timer1 clock
source. When Timer1 Gate signal is inactive, the timer will not increment and hold the current count.
Enable mode is disabled, no incrementing will occur and Timer1 will hold the current count. See figure
below for timing details.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 326
Table 19-3. Timer1 Gate Enable Selections
TMRxCLK GPOL TxG Timer1 Operation
1 1 Counts
1 0 Holds Count
0 1 Holds Count
0 0 Counts
Figure 19-4. Timer1 Gate Enable Mode
TMRxGE
TxGPOL
TxG_IN
TxCKI
TxGVAL
N N + 1 N + 2 N + 3 N + 4
Timer1/3/5/7
Rev. 30-000137A
5/24/2017
19.7.2 Timer1 Gate Source Selection
The gate source for Timer1 is selected using the GSS bits. The polarity selection for the gate source is
controlled by the GPOL bit. The table below lists the gate source selections.
Table 19-4. Timer Gate Sources
GSS
Gate Source
Timer1 Timer3 Timer5
11000-11111 Reserved Reserved Reserved
10111 CLC8_out CLC8_out CLC8_out
10110 CLC7_out CLC7_out CLC7_out
10101 CLC6_out CLC6_out CLC6_out
10100 CLC5_out CLC5_out CLC5_out
10011 CLC4_out CLC4_out CLC4_out
10010 CLC3_out CLC3_out CLC3_out
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 327
...........continued
GSS
Gate Source
Timer1 Timer3 Timer5
10001 CLC2_out CLC2_out CLC2_out
10000 CLC1_out CLC1_out CLC1_out
01111 Reserved Reserved Reserved
01110 ZCDOUT ZCDOUT ZCDOUT
01101 CMP2OUT CMP2OUT CMP2OUT
01100 CMP1OUT CMP1OUT CMP1OUT
01011 PWM4OUT PWM4OUT PWM4OUT
01010 PWM3OUT PWM3OUT PWM3OUT
01001 CCP2OUT CCP2OUT CCP2OUT
01000 CCP1OUT CCP1OUT CCP1OUT
00111 TMR6OUT (post-scaled) TMR6OUT (post-scaled) TMR6OUT (post-scaled)
00110 TMR5 overflow TMR5 overflow Reserved
00101 TMR4OUT (post-scaled) TMR4OUT (post-scaled) TMR4OUT (post-scaled)
00100 TMR3 overflow Reserved TMR3 overflow
00011 TMR2OUT (post-scaled) TMR2OUT (post-scaled) TMR2OUT (post-scaled)
00010 Reserved TMR1 overflow TMR1 overflow
00001 TMR0 overflow TMR0 overflow TMR0 overflow
00000 Pin selected by T1GPPS Pin selected by T3GPPS Pin selected by T5GPPS
Any of the above mentioned signals can be used to trigger the gate. The output of the CMPx can be
synchronized to the Timer1 clock or left asynchronous. For more information refer to the Comparator
Output Synchronization section.
Related Links
33.4.1 Comparator Output Synchronization
19.7.3 Timer1 Gate Toggle Mode
When Timer1 Gate Toggle mode is enabled, it is possible to measure the full-cycle length of a Timer1
gate signal, as opposed to the duration of a single level pulse.
The Timer1 gate source is routed through a flip-flop that changes state on every incrementing edge of the
signal. See figure below for timing details.
Timer1 Gate Toggle mode is enabled by setting the GTM bit. When the GTM bit is cleared, the flip-flop is
cleared and held clear. This is necessary in order to control which edge is measured.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 328
Important:  Enabling Toggle mode at the same time as changing the gate polarity may result in
indeterminate operation.
Figure 19-5. TIMER1 GATE TOGGLE MODE
TMRxGE
TxGPOL
TxGTM
TxTxG_IN
TxCKI
TxGVAL
N N + 1 N + 2 N + 3 N + 4 N + 5 N + 6 N + 7 N + 8
TIMER1/3/5/7
Rev. 30-000138A
5/25/2017
19.7.4 Timer1 Gate Single Pulse Mode
When Timer1 Gate Single Pulse mode is enabled, it is possible to capture a single pulse gate event.
Timer1 Gate Single Pulse mode is first enabled by setting the GSPM bit. Next, the GGO/DONE must be
set. The Timer1 will be fully enabled on the next incrementing edge. On the next trailing edge of the
pulse, the GGO/DONE bit will automatically be cleared. No other gate events will be allowed to increment
Timer1 until the GGO/DONE bit is once again set in software.
Clearing the GSPM bit will also clear the GGO/DONE bit. See figure below for timing details.
Enabling the Toggle mode and the Single Pulse mode simultaneously will permit both sections to work
together. This allows the cycle times on the Timer1 gate source to be measured. See figure below for
timing details.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 329
Figure 19-6. TIMER1 GATE SINGLE PULSE MODE
TMRxGE
TxGPOL
TxG_IN
TxCKI
TxGVAL
N N + 1 N + 2
TxGSPM
TxGGO/
DONE
Set by software
Cleared by hardware on
falling edge of TxGVAL
Set by hardware on
falling edge of TxGVAL
Cleared by software
Cleared by
software
TMRxGIF
Counting enabled on
rising edge of TxG
TIMER1/3/5/7
Rev. 30-000139A
5/25/2017
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 330
Figure 19-7. TIMER1 GATE SINGLE PULSE AND TOGGLE COMBINED MODE
TMRxGE
TxGPOL
TxG_IN
TxCKI
TxGVAL
N N + 1 N + 2
TxGSPM
TxGGO/
DONE
Set by software
Cleared by hardware on
falling edge of TxGVAL
Set by hardware on
falling edge of TxGVAL
Cleared by software
Cleared by
software
TMRxGIF
TxGTM
Counting enabled on
rising edge of TxG
N + 4
N + 3
TIMER1/3/5/7
Rev. 30-000140A
5/25/2017
19.7.5 Timer1 Gate Value Status
When Timer1 Gate Value Status is utilized, it is possible to read the most current level of the gate control
value. The value is stored in the GVAL bit in the TxGCON register. The GVAL bit is valid even when the
Timer1 gate is not enabled (GE bit is cleared).
19.7.6 Timer1 Gate Event Interrupt
When Timer1 gate event interrupt is enabled, it is possible to generate an interrupt upon the completion
of a gate event. When the falling edge of GVAL occurs, the TMRxGIF flag bit in the PIR5 register will be
set. If the TMRxGIE bit in the PIE5 register is set, then an interrupt will be recognized.
The TMRxGIF flag bit operates even when the Timer1 gate is not enabled (GE bit is cleared).
For more information on selecting high or low priority status for the Timer1 gate event interrupt see the
Interrupts chapter.
Related Links
14.2 Interrupt Priority
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Timer1 Module with Gate Control
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19.8 Timer1 Interrupt
The Timer1 register pair (TMRxH:TMRxL) increments to FFFFh and rolls over to 0000h. When Timer1
rolls over, the Timer1 interrupt flag bit of the PIRx register is set. To enable the interrupt-on-rollover, the
following bits must be set:
TMRxON bit of the TxCON register
TMRxIE bits of the PIEx register
PEIE/GIEL bit of the INTCON register
GIE/GIEH bit of the INTCON register
The interrupt is cleared by clearing the TMRxIF bit in the Interrupt Service Routine.
For more information on selecting high or low priority status for the Timer1 overflow interrupt, see the
Interrupts chapter.
Important:  The TMRxH:TMRxL register pair and the TMRxIF bit should be cleared before
enabling interrupts.
Related Links
14.2 Interrupt Priority
19.9 Timer1 Operation During Sleep
Timer1 can only operate during Sleep when set up in Asynchronous Counter mode. In this mode, an
external crystal or clock source can be used to increment the counter. To set up the timer to wake the
device:
TMRxON bit of the TxCON register must be set
TMRxIE bit of the PIEx register must be set
PEIE/GIEL bit of the INTCON register must be set
TxSYNC bit of the TxCON register must be set
Configure the TMRxCLK register for using secondary oscillator as the clock source
Enable the SOSCEN bit of the OSCEN register
The device will wake-up on an overflow and execute the next instruction. If the GIE/GIEH bit of the
INTCON register is set, the device will call the Interrupt Service Routine.
The secondary oscillator will continue to operate in Sleep regardless of the TxSYNC bit setting.
19.10 CCP Capture/Compare Time Base
The CCP modules use the TMRxH:TMRxL register pair as the time base when operating in Capture or
Compare mode.
In Capture mode, the value in the TMRxH:TMRxL register pair is copied into the CCPRxH:CCPRxL
register pair on a configured event.
In Compare mode, an event is triggered when the value in the CCPRxH:CCPRxL register pair matches
the value in the TMRxH:TMRxL register pair. This event can be a Special Event Trigger.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
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For more information, see Capture/Compare/PWM Module(CCP) chapter.
Related Links
21. Capture/Compare/PWM Module
19.11 CCP Special Event Trigger
When any of the CCPs are configured to trigger a special event, the trigger will clear the TMRxH:TMRxL
register pair. This special event does not cause a Timer1 interrupt. The CCP module may still be
configured to generate a CCP interrupt.
In this mode of operation, the CCPRxH:CCPRxL register pair becomes the period register for Timer1.
Timer1 should be synchronized and FOSC/4 should be selected as the clock source in order to utilize the
Special Event Trigger. Asynchronous operation of Timer1 can cause a Special Event Trigger to be
missed.
In the event that a write to TMRxH or TMRxL coincides with a Special Event Trigger from the CCP, the
write will take precedence.
19.12 Peripheral Module Disable
When a peripheral is not used or inactive, the module can be disabled by setting the Module Disable bit in
the PMD registers. This will reduce power consumption to an absolute minimum. Setting the PMD bits
holds the module in Reset and disconnects the module’s clock source. The Module Disable bits for
Timer1 (TMR1MD) are in the PMD1 register. See Peripheral Module Disable (PMD) chapter for more
information.
Related Links
7.3 Register Summary - PMD
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Timer1 Module with Gate Control
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19.13 Register Summary - Timer1
Address Name Bit Pos.
0x0FC0 TMR5
7:0 TMRxL[7:0]
15:8 TMRxH[7:0]
0x0FC2 T5CON 7:0 CKPS[1:0] SYNC RD16 ON
0x0FC3 T5GCON 7:0 GE GPOL GTM GSPM GGO/DONE GVAL
0x0FC4 TMR5GATE 7:0 GSS[4:0]
0x0FC5 TMR5CLK 7:0 CS[4:0]
0x0FC6 TMR3
7:0 TMRxL[7:0]
15:8 TMRxH[7:0]
0x0FC8 T3CON 7:0 CKPS[1:0] SYNC RD16 ON
0x0FC9 T3GCON 7:0 GE GPOL GTM GSPM GGO/DONE GVAL
0x0FCA TMR3GATE 7:0 GSS[4:0]
0x0FCB TMR3CLK 7:0 CS[4:0]
0x0FCC TMR1
7:0 TMRxL[7:0]
15:8 TMRxH[7:0]
0x0FCE T1CON 7:0 CKPS[1:0] SYNC RD16 ON
0x0FCF T1GCON 7:0 GE GPOL GTM GSPM GGO/DONE GVAL
0x0FD0 TMR1GATE 7:0 GSS[4:0]
0x0FD1 TMR1CLK 7:0 CS[4:0]
19.14 Register Definitions: Timer1
Long bit name prefixes for the odd numbered timers is shown in the following table. Refer to the "Long Bit
Names" section for more information.
Table 19-5. Timer1 prefixes
Peripheral Bit Name Prefix
Timer1 T1
Timer3 T3
Timer5 T5
Related Links
1.4.2.2 Long Bit Names
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Timer1 Module with Gate Control
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19.14.1 TxCON
Name:  TxCON
Address:  0xFCE,0xFC8,0xFC2
Timer Control Register
Bit 7 6 5 4 3 2 1 0
CKPS[1:0] SYNC RD16 ON
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 5:4 – CKPS[1:0] Timer Input Clock Prescale Select bits
Reset States: POR/BOR = 00
All Other Resets = uu
Value Description
11 1:8 Prescale value
10 1:4 Prescale value
01 1:2 Prescale value
00 1:1 Prescale value
Bit 2 – SYNC Timer External Clock Input Synchronization Control bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Condition Description
XCS = FOSC/4 or FOSC This bit is ignored. Timer uses the incoming clock as is.
1Else Do not synchronize external clock input
0Else Synchronize external clock input with system clock
Bit 1 – RD16 16-Bit Read/Write Mode Enable bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Enables register read/write of Timer in one 16-bit operation
0Enables register read/write of Timer in two 8-bit operations
Bit 0 – ON Timer On bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Enables Timer
0Disables Timer
PIC18F26/45/46Q10
Timer1 Module with Gate Control
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19.14.2 TxGCON
Name:  TxGCON
Address:  0xFCF,0xFC9,0xFC3
Timer Gate Control Register
Bit 7 6 5 4 3 2 1 0
GE GPOL GTM GSPM GGO/DONE GVAL
Access R/W R/W R/W R/W R/W RO
Reset 0 0 0 0 0 x
Bit 7 – GE Timer Gate Enable bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Condition Description
1ON = 1Timer counting is controlled by the Timer gate function
0ON = 1Timer is always counting
XON = 0This bit is ignored
Bit 6 – GPOL Timer Gate Polarity bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Timer gate is active-high (Timer counts when gate is high)
0Timer gate is active-low (Timer counts when gate is low)
Bit 5 – GTM Timer Gate Toggle Mode bit
Timer Gate Flip-Flop Toggles on every rising edge when Toggle mode is enabled.
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Timer Gate Toggle mode is enabled
0Timer Gate Toggle mode is disabled and Toggle flip-flop is cleared
Bit 4 – GSPM Timer Gate Single Pulse Mode bit
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Timer Gate Single Pulse mode is enabled and is controlling Timer gate)
0Timer Gate Single Pulse mode is disabled
Bit 3 – GGO/DONE Timer Gate Single Pulse Acquisition Status bit
This bit is automatically cleared when TxGSPM is cleared.
Reset States: POR/BOR = 0
All Other Resets = u
Value Description
1Timer Gate Single Pulse Acquisition is ready, waiting for an edge
0Timer Gate Single Pulse Acquisition has completed or has not been started.
PIC18F26/45/46Q10
Timer1 Module with Gate Control
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Bit 2 – GVAL Timer Gate Current State bit
Indicates the current state of the timer gate that could be provided to TMRxH:TMRxL
Unaffected by Timer Gate Enable (TMRxGE)
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 337
19.14.3 TMRxCLK
Name:  TMRxCLK
Address:  0xFD1,0xFCB,0xFC5
Timer Clock Source Selection Register
Bit 7 6 5 4 3 2 1 0
CS[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – CS[4:0] Timer Clock Source Selection bits
Refer to the clock source selection table.
Reset States: POR/BOR = 00000
All Other Resets = uuuuu
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 338
19.14.4 TMRxGATE
Name:  TMRxGATE
Address:  0xFD0,0xFCA,0xFC4
Timer Gate Source Selection Register
Bit 7 6 5 4 3 2 1 0
GSS[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – GSS[4:0] Timer Gate Source Selection bits
Refer to the gate source selection table.
Reset States: POR/BOR = 00000
All Other Resets = uuuuu
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 339
19.14.5 TMRx
Name:  TMRx
Address:  0xFCC,0xFC6,0xFC0
Timer Low Byte Register
Bit 15 14 13 12 11 10 9 8
TMRxH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
TMRxL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – TMRxH[7:0] Timer Most Significant Byte
Reset States: POR/BOR = 00000000
All Other Resets = uuuuuuuu
Bits 7:0 – TMRxL[7:0] Timer Least Significant Byte
Reset States: POR/BOR = 00000000
All Other Resets = uuuuuuuu
PIC18F26/45/46Q10
Timer1 Module with Gate Control
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 340
20. Timer2 Module
The Timer2 module is a 8-bit timer that incorporates the following features:
8-Bit Timer and Period Registers
Readable and Writable
Software Programmable Prescaler (1:1 to 1:128)
Software Programmable Postscaler (1:1 to 1:16)
Interrupt on T2TMR Match with T2PR
One-Shot Operation
Full Asynchronous Operation
Includes Hardware Limit Timer (HLT)
Alternate Clock Sources
External Timer Reset Signal Sources
Configurable Timer Reset Operation
See Figure 20-1 for a block diagram of Timer2. See table below for the clock source selections.
Important:  References to module Timer2 apply to all the even numbered timers on this device.
(Timer2, Timer4, etc.)
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 341
Figure 20-1. Timer2 with Hardware Limit Timer (HLT) Block Diagram
Rev. 10-000168C
9/10/2015
MODE<3>
Clear ON
TxTMR
Comparator
TxPR
CSYNC
ON
OUTPS<3:0>
Postscaler
Set flag bit
TMRxIF
TMRx_postscaled
CPOL
4
MODE<4:0>
PSYNC
Prescaler
CKPS<2:0>
3
TMRx_clk
RSEL <4:0>
R
Sync
(2 Clocks)
Edge Detector
Level Detector
Mode Control
(2 clock Sync)
TMRx_ers
0
1
1
0
enable
reset
Sync
Fosc/4
D Q
CCP_pset(1)
MODE<4:1>=1011
MODE<4:3>=01
PPS
INPPS
TxIN
External
Reset
Sources
(2)
Note: 
1. Signal to the CCP to trigger the PWM pulse.
2. See TxRST for external Reset sources.
Table 20-1. Clock Source Selection
CS<4:0>
Clock Source
Timer2 Timer4 Timer6
11111-11000 Reserved Reserved Reserved
10111 CLC8_out CLC8_out CLC8_out
10110 CLC7_out CLC7_out CLC7_out
10101 CLC6_out CLC6_out CLC6_out
10100 CLC5_out CLC5_out CLC5_out
10011 CLC4_out CLC4_out CLC4_out
10010 CLC3_out CLC3_out CLC3_out
10001 CLC2_out CLC2_out CLC2_out
10000 CLC1_out CLC1_out CLC1_out
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 342
...........continued
CS<4:0>
Clock Source
Timer2 Timer4 Timer6
01111-01001 Reserved Reserved Reserved
01000 ZCD_OUT ZCD_OUT ZCD_OUT
00111 CLKREF_OUT CLKREF_OUT CLKREF_OUT
00110 SOSC SOSC SOSC
00101 MFINTOSC (31 kHz) MFINTOSC (31 kHz) MFINTOSC (31 kHz)
00100 LFINTOSC LFINTOSC LFINTOSC
00011 HFINTOSC HFINTOSC HFINTOSC
00010 FOSC FOSC FOSC
00001 FOSC/4 FOSC/4 FOSC/4
00000 Pin selected by T2INPPS Pin selected by T4INPPS Pin selected by T6INPPS
20.1 Timer2 Operation
Timer2 operates in three major modes:
Free Running Period
One-shot
Monostable
Within each mode there are several options for starting, stopping, and reset. Table 20-3 lists the options.
In all modes, the T2TMR count register is incremented on the rising edge of the clock signal from the
programmable prescaler. When T2TMR equals T2PR, a high level is output to the postscaler counter.
T2TMR is cleared on the next clock input.
An external signal from hardware can also be configured to gate the timer operation or force a T2TMR
count Reset. In Gate modes the counter stops when the gate is disabled and resumes when the gate is
enabled. In Reset modes the T2TMR count is reset on either the level or edge from the external source.
The T2TMR and T2PR registers are both directly readable and writable. The T2TMR register is cleared
and the T2PR register initializes to FFh on any device Reset. Both the prescaler and postscaler counters
are cleared on the following events:
A write to the T2TMR register
A write to the T2CON register
Any device Reset
External Reset Source event that resets the timer.
Important:  T2TMR is not cleared when T2CON is written.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 343
20.1.1 Free-Running Period Mode
The value of T2TMR is compared to that of the Period register, T2PR, on each clock cycle. When the two
values match, the comparator resets the value of T2TMR to 00h on the next cycle and increments the
output postscaler counter. When the postscaler count equals the value in the OUTPS bits of the T2CON
register then a one clock period wide pulse occurs on the TMR2_postscaled output, and the postscaler
count is cleared.
20.1.2 One-Shot Mode
The One-Shot mode is identical to the Free-Running Period mode except that the ON bit is cleared and
the timer is stopped when T2TMR matches T2PR and will not restart until the ON bit is cycled off and on.
Postscaler (OUTPS) values other than zero are ignored in this mode because the timer is stopped at the
first period event and the postscaler is reset when the timer is restarted.
20.1.3 Monostable Mode
Monostable modes are similar to One-Shot modes except that the ON bit is not cleared and the timer can
be restarted by an external Reset event.
20.2 Timer2 Output
The Timer2 module’s primary output is TMR2_postscaled, which pulses for a single TMR2_clk period
upon each match of the postscaler counter and the OUTPS bits of the T2CON register. The postscaler is
incremented each time the T2TMR value matches the T2PR value. This signal can be selected as an
input to several other input modules:
The ADC module, as an auto-conversion trigger
CWG, as an auto-shutdown source
The CRC memory scanner, as a trigger for triggered mode
Gate source for odd numbered timers (Timer1, Timer3, etc.)
Alternate SPI clock
Reset signals for other instances of even numbered timers (Timer2, Timer4, etc.)
In addition, the Timer2 is also used by the CCP module for pulse generation in PWM mode. See “PWM
Overview” and “Pulse-width Modulation” sections for more details on setting up Timer2 for use with the
CCP and PWM modules.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.3 External Reset Sources
In addition to the clock source, the Timer2 also takes in an external Reset source. This external Reset
source is selected for each timer with the corresponding TxRST register. This source can control starting
and stopping of the timer, as well as resetting the timer, depending on which mode the timer is in. Reset
source selections are shown in the following table.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 344
Table 20-2. External Reset Sources
RSEL[4:0]
Reset Source
TMR2 TMR4 TMR6
11000-11111 Reserved Reserved Reserved
10111 CLC8_out CLC8_out CLC8_out
10110 CLC7_out CLC7_out CLC7_out
10101 CLC6_out CLC6_out CLC6_out
10100 CLC5_out CLC5_out CLC5_out
10011 CLC4_out CLC4_out CLC4_out
10010 CLC3_out CLC3_out CLC3_out
10001 CLC2_out CLC2_out CLC2_out
10000 CLC1_out CLC1_out CLC1_out
01111 EUSART2 TX/CK EUSART2 TX/CK EUSART2 TX/CK
01110 EUSART2 DT EUSART2 DT EUSART2 DT
01101 EUSART1 TX/CK EUSART1 TX/CK EUSART1 TX/CK
01100 EUSART1 DT EUSART1 DT EUSART1 DT
01011 Reserved Reserved Reserved
01010 ZCD_OUT ZCD_OUT ZCD_OUT
1001 CMP2OUT CMP2OUT CMP2OUT
01000 CMP1OUT CMP1OUT CMP1OUT
00111 PWM4OUT PWM4OUT PWM4OUT
00110 PWM3OUT PWM3OUT PWM3OUT
00101 CCP2OUT CCP2OUT CCP2OUT
00100 CCP1OUT CCP1OUT CCP1OUT
00011 TMR6 post-scaled TMR6 post-scaled Reserved
00010 TMR4 post-scaled Reserved TMR4 post-scaled
00001 Reserved TMR2 post-scaled TMR2 post-scaled
00000 Pin selected by T2INPPS Pin selected by T4INPPS Pin selected by T6INPPS
20.4 Timer2 Interrupt
Timer2 can also generate a device interrupt. The interrupt is generated when the postscaler counter
matches with the selected postscaler value (OUTPS bits of T2CON register). The interrupt is enabled by
setting the TMR2IE interrupt enable bit. Interrupt timing is illustrated in the figure below.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 345
Figure 20-2. Timer2 Prescaler, Postscaler, and Interrupt Timing Diagram
Rev. 10-000205A
4/7/2016
TMRx_clk
PRx
TMRx
1
0
CKPS 0b010
TMRx_postscaled
OUTPS 0b0001
101010
TMRxIF (1)(1) (2)
Note: 
1. Setting the interrupt flag is synchronized with the instruction clock.
2. Cleared by software.
20.5 Operating Modes
The mode of the timer is controlled by the MODE bits of the T2HLT register. Edge-Triggered modes
require six Timer clock periods between external triggers. Level-Triggered modes require the triggering
level to be at least three Timer clock periods long. External triggers are ignored while in Debug mode.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 346
Table 20-3. Operating Modes Table
Mode
MODE<4:0> Output
Operation Operation
Timer Control
<4:3> <2:0> Start Reset Stop
Free-
Running
Period
00
000
Period Pulse
Software gate
(Figure 20-3)
ON = 1 ON = 0
001
Hardware
gate, active-
high
(Figure 20-4)
ON = 1 and
TMRx_ers =
1
ON = 0 or
TMRx_ers = 0
010
Hardware
gate, active-
low
ON = 1 and
TMRx_ers =
0
ON = 0 or
TMRx_ers = 1
011
Period
Pulse
with
Hardware
Reset
Rising or
falling edge
Reset
ON = 1
TMRx_ers
ON = 0
100
Rising edge
Reset (Figure
20-5)
TMRx_ers
101 Falling edge
Reset
TMRx_ers
110 Low level
Reset
TMRx_ers
= 0
ON = 0 or
TMRx_ers = 0
111
High level
Reset (Figure
20-6)
TMRx_ers
= 1
ON = 0 or
TMRx_ers = 1
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 347
...........continued
Mode
MODE<4:0> Output
Operation Operation
Timer Control
<4:3> <2:0> Start Reset Stop
One-shot 01
000 One-shot Software start
(Figure 20-7)
ON = 1
ON = 0
or
Next clock after
TMRx = PRx
(Note 2)
001
Edge-
Triggered
Start
(Note 1)
Rising edge
start (Figure
20-8)
ON = 1 and
TMRx_ers ↑
010 Falling edge
start
ON = 1 and
TMRx_ers ↓
011 Any edge
start
ON = 1 and
TMRx_ers ↕
100
Edge-
Triggered
Start
and
Hardware
Reset
(Note 1)
Rising edge
start and
Rising edge
Reset (Figure
20-9)
ON = 1 and
TMRx_ers ↑
TMRx_ers
101
Falling edge
start and
Falling edge
Reset
ON = 1 and
TMRx_ers ↓
TMRx_ers
110
Rising edge
start and
Low level
Reset (Figure
20-10)
ON = 1 and
TMRx_ers ↑
TMRx_ers
= 0
111
Falling edge
start and
High level
Reset
ON = 1 and
TMRx_ers ↓
TMRx_ers
= 1
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 348
...........continued
Mode
MODE<4:0> Output
Operation Operation
Timer Control
<4:3> <2:0> Start Reset Stop
Mono-
stable
10
000 Reserved
001 Edge-
Triggered
Start
(Note 1)
Rising edge
start
(Figure 20-11)
ON = 1 and
TMRx_ers ↑ ON = 0
or
Next clock after
TMRx = PRx
(Note 3)
010 Falling edge
start
ON = 1 and
TMRx_ers ↓
011 Any edge
start
ON = 1 and
TMRx_ers ↕
Reserved 100 Reserved
Reserved 101 Reserved
One-shot
110
Level
Triggered
Start
and
Hardware
Reset
High level
start and
Low level
Reset (Figure
20-12)
ON = 1 and
TMRx_ers =
1
TMRx_ers
= 0ON = 0 or
Held in Reset
(Note 2)
111
Low level
start and
High level
Reset
ON = 1 and
TMRx_ers =
0
TMRx_ers
= 1
Reserved 11 xxx Reserved
Note: 
1. If ON = 0 then an edge is required to restart the timer after ON = 1.
2. When T2TMR = T2PR then the next clock clears ON and stops T2TMR at 00h.
3. When T2TMR = T2PR then the next clock stops T2TMR at 00h but does not clear ON.
20.6 Operation Examples
Unless otherwise specified, the following notes apply to the following timing diagrams:
Both the prescaler and postscaler are set to 1:1 (both the CKPS and OUTPS bits in the T2CON
register are cleared).
The diagrams illustrate any clock except FOSC/4 and show clock-sync delays of at least two full
cycles for both ON and Timer2_ers. When using FOSC/4, the clock-sync delay is at least one
instruction period for Timer2_ers; ON applies in the next instruction period.
ON and Timer2_ers are somewhat generalized, and clock-sync delays may produce results that are
slightly different than illustrated.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 349
The PWM Duty Cycle and PWM output are illustrated assuming that the timer is used for the PWM
function of the CCP module as described in the “PWM Overview” section. The signals are not a part
of the Timer2 module.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.1 Software Gate Mode
This mode corresponds to legacy Timer2 operation. The timer increments with each clock input when ON
= 1 and does not increment when ON = 0. When the TMRx count equals the PRx period count the timer
resets on the next clock and continues counting from 0. Operation with the ON bit software controlled is
illustrated in Figure 20-3. With PRx = 5, the counter advances until TMRx = 5, and goes to zero with the
next clock.
Figure 20-3. Software Gate Mode Timing Diagram (MODE = 00000)
Rev. 10-000195B
5/30/2014
TMRx_clk
Instruction(1)
ON
PRx
TMRx
TMRx_postscaled
BSF BCF BSF
5
0 1 2 3 4 5 0 1 2 2 3 4 5
MODE 0b00000
3 4 5 0 1 0 1
PWM Duty
Cycle 3
PWM Output
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.2 Hardware Gate Mode
The Hardware Gate modes operate the same as the Software Gate mode except the TMRx_ers external
signal can also gate the timer. When used with the CCP, the gating extends the PWM period. If the timer
is stopped when the PWM output is high, then the duty cycle is also extended.
When MODE<4:0> = 00001 then the timer is stopped when the external signal is high. When
MODE<4:0> = 00010, then the timer is stopped when the external signal is low.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 350
Figure 20-4 illustrates the Hardware Gating mode for MODE<4:0> = 00001 in which a high input level
starts the counter.
Figure 20-4. Hardware Gate Mode Timing Diagram (MODE = 00001)
Rev. 10-000 196B
5/30/201 4
TMRx_clk
TMRx_ers
PRx
TMRx
TMRx_postscaled
5
MODE 0b00001
0 1 2 3 4 5 0 1 2 3 4 5 0 1
PWM Duty
Cycle 3
PWM Output
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.3 Edge-Triggered Hardware Limit Mode
In Hardware Limit mode, the timer can be reset by the TMRx_ers external signal before the timer reaches
the period count. Three types of Resets are possible:
Reset on rising or falling edge (MODE<4:0>= 00011)
Reset on rising edge (MODE<4:0> = 00100)
Reset on falling edge (MODE<4:0> = 00101)
When the timer is used in conjunction with the CCP in PWM mode then an early Reset shortens the
period and restarts the PWM pulse after a two clock delay. Refer to Figure 20-5.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 351
Figure 20-5. Edge-Triggered Hardware Limit Mode Timing Diagram
(MODE = 00100)
Rev. 10-000 197B
5/30/201 4
TMRx_clk
ON
PRx
TMRx
BSF BCF BSF
5
0 1 2 0 1 2 3 4 5 0 4 5 0
MODE 0b00100
TMRx_ers
1 2 3 1
TMRx_postscaled
PWM Duty
Cycle 3
PWM Output
Instruction(1)
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.4 Level-Triggered Hardware Limit Mode
In the Level-Triggered Hardware Limit Timer modes the counter is reset by high or low levels of the
external signal TMRx_ers, as shown in Figure 20-6. Selecting MODE<4:0> = 00110 will cause the timer
to reset on a low level external signal. Selecting MODE<4:0> = 00111 will cause the timer to reset on a
high level external signal. In the example, the counter is reset while TMRx_ers = 1. ON is controlled by
BSF and BCF instructions. When ON = 0 the external signal is ignored.
When the CCP uses the timer as the PWM time base then the PWM output will be set high when the
timer starts counting and then set low only when the timer count matches the CCPRx value. The timer is
reset when either the timer count matches the PRx value or two clock periods after the external Reset
signal goes true and stays true.
The timer starts counting, and the PWM output is set high, on either the clock following the PRx match or
two clocks after the external Reset signal relinquishes the Reset. The PWM output will remain high until
the timer counts up to match the CCPRx pulse width value. If the external Reset signal goes true while
the PWM output is high then the PWM output will remain high until the Reset signal is released allowing
the timer to count up to match the CCPRx value.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 352
Figure 20-6. Level-Triggered Hardware Limit Mode Timing Diagram
(MODE = 00111)
Rev. 10-000198B
5/30/2014
TMRx_clk
ON
PRx
TMRx
BSF BCF BSF
5
0 1 2 0 1 2 3 4 5 1 2 3
MODE 0b00111
TMRx_ers
00 4
TMRx_postscaled
5 0
PWM Duty
Cycle 3
PWM Output
Instruction(1)
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.5 Software Start One-Shot Mode
In One-Shot mode the timer resets and the ON bit is cleared when the timer value matches the PRx
period value. The ON bit must be set by software to start another timer cycle. Setting MODE<4:0> =
01000 selects One-Shot mode which is illustrated in Figure 20-7. In the example, ON is controlled by
BSF and BCF instructions. In the first case, a BSF instruction sets ON and the counter runs to completion
and clears ON. In the second case, a BSF instruction starts the cycle, BCF/BSF instructions turn the
counter off and on during the cycle, and then it runs to completion.
When One-Shot mode is used in conjunction with the CCP PWM operation the PWM pulse drive starts
concurrent with setting the ON bit. Clearing the ON bit while the PWM drive is active will extend the PWM
drive. The PWM drive will terminate when the timer value matches the CCPRx pulse width value. The
PWM drive will remain off until software sets the ON bit to start another cycle. If software clears the ON
bit after the CCPRx match but before the PRx match then the PWM drive will be extended by the length
of time the ON bit remains cleared. Another timing cycle can only be initiated by setting the ON bit after it
has been cleared by a PRx period count match.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 353
Figure 20-7. Software Start One-Shot Mode Timing Diagram (MODE = 01000)
Rev. 10-000199B
4/7/2016
TMRx_clk
ON
PRx
TMRx
BSF BSF
5
0 1 2 3 4 5 0 431
MODE 0b01000
2 5 0
TMRx_postscaled
BCF BSF
PWM Duty
Cycle 3
PWM Output
Instruction(1)
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.6 Edge-Triggered One-Shot Mode
The Edge-Triggered One-Shot modes start the timer on an edge from the external signal input, after the
ON bit is set, and clear the ON bit when the timer matches the PRx period value. The following edges will
start the timer:
Rising edge (MODE<4:0> = 01001)
Falling edge (MODE<4:0> = 01010)
Rising or Falling edge (MODE<4:0> = 01011)
If the timer is halted by clearing the ON bit then another TMRx_ers edge is required after the ON bit is set
to resume counting. Figure 20-8 illustrates operation in the rising edge One-Shot mode.
When Edge-Triggered One-Shot mode is used in conjunction with the CCP then the edge-trigger will
activate the PWM drive and the PWM drive will deactivate when the timer matches the CCPRx pulse
width value and stay deactivated when the timer halts at the PRx period count match.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 354
Figure 20-8. Edge-Triggered One-Shot Mode Timing Diagram (MODE = 01001)
Rev. 10-000200B
5/19/2016
TMRx_clk
ON
PRx
TMRx
BSF BSF
5
0 1 2 3 4 5 0 1
MODE 0b01001
2
CCP_pset
TMRx_postscaled
BCF
TMRx_ers
PWM Duty
Cycle 3
PWM Output
Instruction(1)
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.7 Edge-Triggered Hardware Limit One-Shot Mode
In Edge-Triggered Hardware Limit One-Shot modes the timer starts on the first external signal edge after
the ON bit is set and resets on all subsequent edges. Only the first edge after the ON bit is set is needed
to start the timer. The counter will resume counting automatically two clocks after all subsequent external
Reset edges. Edge triggers are as follows:
Rising edge start and Reset (MODE<4:0> = 01100)
Falling edge start and Reset (MODE<4:0> = 01101)
The timer resets and clears the ON bit when the timer value matches the PRx period value. External
signal edges will have no effect until after software sets the ON bit. Figure 20-9 illustrates the rising edge
hardware limit one-shot operation.
When this mode is used in conjunction with the CCP then the first starting edge trigger, and all
subsequent Reset edges, will activate the PWM drive. The PWM drive will deactivate when the timer
matches the CCPRx pulse-width value and stay deactivated until the timer halts at the PRx period match
unless an external signal edge resets the timer before the match occurs.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 355
Figure 20-9. Edge-Triggered Hardware Limit One-Shot Mode Timing Diagram (MODE = 01100)
Rev. 10-000201B
4/7/2016
TMRx_clk
ON
PRx
TMRx
BSF BSF
5
0 1 2 3 4 5 0 01
MODE 0b01100
2
TMRx_postscaled
TMRx_ers
1 2 3 4 5 0
PWM Duty
Cycle 3
PWM Output
Instruction(1)
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.8 Level Reset, Edge-Triggered Hardware Limit One-Shot Modes
In Level -Triggered One-Shot mode the timer count is reset on the external signal level and starts
counting on the rising/falling edge of the transition from Reset level to the active level while the ON bit is
set. Reset levels are selected as follows:
Low Reset level (MODE<4:0> = 01110)
High Reset level (MODE<4:0> = 01111)
When the timer count matches the PRx period count, the timer is reset and the ON bit is cleared. When
the ON bit is cleared by either a PRx match or by software control, a new external signal edge is required
after the ON bit is set to start the counter.
When Level-Triggered Reset One-Shot mode is used in conjunction with the CCP PWM operation, the
PWM drive goes active with the external signal edge that starts the timer. The PWM drive goes inactive
when the timer count equals the CCPRx pulse width count. The PWM drive does not go active when the
timer count clears at the PRx period count match.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 356
Figure 20-10. Low Level Reset, Edge-Triggered Hardware Limit One-Shot Mode Timing Diagram
(MODE = 01110)
Rev. 10-000202B
4/7/2016
TMRx_clk
ON
PRx
TMRx
BSF BSF
5
0 1 2 3 4 5 0 01
MODE 0b01110
TMRx_postscaled
TMRx_ers
1 2 3 4 0
PWM Duty
Cycle 3
PWM Output
5
Instruction(1)
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.9 Edge-Triggered Monostable Modes
The Edge-Triggered Monostable modes start the timer on an edge from the external Reset signal input,
after the ON bit is set, and stop incrementing the timer when the timer matches the PRx period value. The
following edges will start the timer:
Rising edge (MODE<4:0> = 10001)
Falling edge (MODE<4:0> = 10010)
Rising or Falling edge (MODE<4:0> = 10011)
When an Edge-Triggered Monostable mode is used in conjunction with the CCP PWM operation, the
PWM drive goes active with the external Reset signal edge that starts the timer, but will not go active
when the timer matches the PRx value. While the timer is incrementing, additional edges on the external
Reset signal will not affect the CCP PWM.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 357
Figure 20-11. Rising Edge-Triggered Monostable Mode Timing Diagram (MODE = 10001)
Rev. 10-000203A
4/7/2016
TMRx_clk
ON
PRx
TMRx
BSF BCF
5
0 1 2 3 4 5 0 1
MODE 0b10001
TMRx_postscaled
TMRx_ers
2 3 4 5 0
PWM Duty
Cycle 3
PWM Output
Instruction(1) BSF BCF BSF
1 2 3 4 5 0
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.6.10 Level-Triggered Hardware Limit One-Shot Modes
The Level-Triggered Hardware Limit One-Shot modes hold the timer in Reset on an external Reset level
and start counting when both the ON bit is set and the external signal is not at the Reset level. If one of
either the external signal is not in Reset or the ON bit is set, then the other signal being set/made active
will start the timer. Reset levels are selected as follows:
Low Reset level (MODE<4:0> = 10110)
High Reset level (MODE<4:0> = 10111)
When the timer count matches the PRx period count, the timer is reset and the ON bit is cleared. When
the ON bit is cleared by either a PRx match or by software control, the timer will stay in Reset until both
the ON bit is set and the external signal is not at the Reset level.
When Level-Triggered Hardware Limit One-Shot modes are used in conjunction with the CCP PWM
operation, the PWM drive goes active with either the external signal edge or the setting of the ON bit,
whichever of the two starts the timer.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 358
Figure 20-12. Level-Triggered hardware Limit one-Shot Mode Timing Diagram (MODE = 10110)
Rev. 10-000204A
4/7/2016
TMR2_clk
Instruction(1)
ON
PRx
TMRx
BSF BSF
5
0 1 2 3 4 5 0 1
MODE 0b10110
TMR2_postscaled
TMR2_ers
2 1 20
PWM Duty
Cycle ‘D3
PWM Output
3 3 4 5 0
BSFBCF
Note: 
1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or
clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.
Related Links
21.4 PWM Overview
22. (PWM) Pulse-Width Modulation
20.7 Timer2 Operation During Sleep
When PSYNC = 1, Timer2 cannot be operated while the processor is in Sleep mode. The contents of the
T2TMR and T2PR registers will remain unchanged while processor is in Sleep mode.
When PSYNC = 0, Timer2 will operate in Sleep as long as the clock source selected is also still running.
If any internal oscillator is selected as the clock source, it will stay active during Sleep mode.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 359
20.8 Register Summary - Timer2
Address Name Bit Pos.
0x0FAE T6TMR 7:0 TxTMR[7:0]
0x0FAF T6PR 7:0 TxPR[7:0]
0x0FB0 T6CON 7:0 ON CKPS[2:0] OUTPS[3:0]
0x0FB1 T6HLT 7:0 PSYNC CPOL CSYNC MODE[4:0]
0x0FB2 T6CLKCON 7:0 CS[4:0]
0x0FB3 T6RST 7:0 RSEL[4:0]
0x0FB4 T4TMR 7:0 TxTMR[7:0]
0x0FB5 T4PR 7:0 TxPR[7:0]
0x0FB6 T4CON 7:0 ON CKPS[2:0] OUTPS[3:0]
0x0FB7 T4HLT 7:0 PSYNC CPOL CSYNC MODE[4:0]
0x0FB8 T4CLKCON 7:0 CS[4:0]
0x0FB9 T4RST 7:0 RSEL[4:0]
0x0FBA T2TMR 7:0 TxTMR[7:0]
0x0FBB T2PR 7:0 TxPR[7:0]
0x0FBC T2CON 7:0 ON CKPS[2:0] OUTPS[3:0]
0x0FBD T2HLT 7:0 PSYNC CPOL CSYNC MODE[4:0]
0x0FBE T2CLKCON 7:0 CS[4:0]
0x0FBF T2RST 7:0 RSEL[4:0]
20.9 Register Definitions: Timer2 Control
Long bit name prefixes for the Timer2 peripherals are shown in table below. Refer to Section "Long Bit
Names" for more information.
Table 20-4. Timer2 long bit name prefixes
Peripheral Bit Name Prefix
Timer2 T2
Timer4 T4
Timer6 T6
Notice:  References to module Timer2 apply to all the even numbered timers on this device.
(Timer2, Timer4, etc.)
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 360
20.9.1 TxTMR
Name:  TxTMR
Address:  0xFBA,0xFB4,0xFAE
Timer Counter Register
Bit 7 6 5 4 3 2 1 0
TxTMR[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – TxTMR[7:0] Timerx Counter bits
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 361
20.9.2 TxPR
Name:  TxPR
Address:  0xFBB,0xFB5,0xFAF
Timer Period Register
Bit 7 6 5 4 3 2 1 0
TxPR[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 7:0 – TxPR[7:0] Timer Period Register bits
Value Description
0 - 255 The timer restarts at ‘0’ when TxTMR reaches TxPR value
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 362
20.9.3 TxCON
Name:  TxCON
Address:  0xFBC,0xFB6,0xFB0
Timerx Control Register
Bit 7 6 5 4 3 2 1 0
ON CKPS[2:0] OUTPS[3:0]
Access R/W/HC R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – ON
Timer On bit(1)
Value Description
1Timer is on
0Timer is off: all counters and state machines are reset
Bits 6:4 – CKPS[2:0] Timer Clock Prescale Select bits
Value Description
111 1:128 Prescaler
110 1:64 Prescaler
101 1:32 Prescaler
100 1:16 Prescaler
011 1:8 Prescaler
010 1:4 Prescaler
001 1:2 Prescaler
000 1:1 Prescaler
Bits 3:0 – OUTPS[3:0] Timer Output Postscaler Select bits
Value Description
1111 1:16 Postscaler
1110 1:15 Postscaler
1101 1:14 Postscaler
1100 1:13 Postscaler
1011 1:12 Postscaler
1010 1:11 Postscaler
1001 1:10 Postscaler
1000 1:9 Postscaler
0111 1:8 Postscaler
0110 1:7 Postscaler
0101 1:6 Postscaler
0100 1:5 Postscaler
0011 1:4 Postscaler
0010 1:3 Postscaler
0001 1:2 Postscaler
0000 1:1 Postscaler
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 363
Note: 
1. In certain modes, the ON bit will be auto-cleared by hardware. See Table 20-3.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 364
20.9.4 TxHLT
Name:  TxHLT
Address:  0xFBD,0xFB7,0xFB1
Timer Hardware Limit Control Register
Bit 7 6 5 4 3 2 1 0
PSYNC CPOL CSYNC MODE[4:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – PSYNC
Timer Prescaler Synchronization Enable bit(1, 2)
Value Description
1Timer Prescaler Output is synchronized to FOSC/4
0Timer Prescaler Output is not synchronized to FOSC/4
Bit 6 – CPOL
Timer Clock Polarity Selection bit(3)
Value Description
1Falling edge of input clock clocks timer/prescaler
0Rising edge of input clock clocks timer/prescaler
Bit 5 – CSYNC
Timer Clock Synchronization Enable bit(4, 5)
Value Description
1ON bit is synchronized to timer clock input
0ON bit is not synchronized to timer clock input
Bits 4:0 – MODE[4:0]
Timer Control Mode Selection bits(6, 7)
Value Description
00000
to
11111
See Table 20-3
Note: 
1. Setting this bit ensures that reading TxTMR will return a valid data value.
2. When this bit is ‘1’, Timer cannot operate in Sleep mode.
3. CKPOL should not be changed while ON = 1.
4. Setting this bit ensures glitch-free operation when the ON is enabled or disabled.
5. When this bit is set then the timer operation will be delayed by two input clocks after the ON bit is
set.
6. Unless otherwise indicated, all modes start upon ON = 1 and stop upon ON = 0 (stops occur
without affecting the value of TxTMR).
7. When TxTMR = TxPR, the next clock clears TxTMR, regardless of the operating mode.
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 365
20.9.5 TxCLKCON
Name:  TxCLKCON
Address:  0xFBE,0xFB8,0xFB2
Timer Clock Source Selection Register
Bit 7 6 5 4 3 2 1 0
CS[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – CS[4:0] Timer Clock Source Selection bits
Value Description
nSee Clock Source Selection table
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 366
20.9.6 TxRST
Name:  TxRST
Address:  0xFBF,0xFB9,0xFB3
Timer External Reset Signal Selection Register
Bit 7 6 5 4 3 2 1 0
RSEL[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – RSEL[4:0]
External Reset Source Selection Bits
Value Description
nSee External Reset Sources table
PIC18F26/45/46Q10
Timer2 Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 367
21. Capture/Compare/PWM Module
The Capture/Compare/PWM module is a peripheral that allows the user to time and control different
events, and to generate Pulse-Width Modulation (PWM) signals. In Capture mode, the peripheral allows
the timing of the duration of an event. The Compare mode allows the user to trigger an external event
when a predetermined amount of time has expired. The PWM mode can generate Pulse-Width
Modulated signals of varying frequency and duty cycle.
This family of devices contains two standard Capture/Compare/PWM modules (CCP1 and CCP2). Each
individual CCP module can select the timer source that controls the module. Each module has an
independent timer selection which can be accessed using the CxTSEL bits in the CCPTMRS register.
The default timer selection is TMR1 when using Capture/Compare mode and T2TMR when using PWM
mode in the CCPx module.
It should be noted that the Capture/Compare mode operation is described with respect to TMR1 and the
PWM mode operation is described with respect to T2TMR in the following sections.
The Capture and Compare functions are identical for all CCP modules.
Important: 
1. In devices with more than one CCP module, it is very important to pay close attention to
the register names used. A number placed after the module acronym is used to
distinguish between separate modules. For example, the CCP1CON and CCP2CON
control the same operational aspects of two completely different CCP modules.
2. Throughout this section, generic references to a CCP module in any of its operating
modes may be interpreted as being equally applicable to CCPx module. Register names,
module signals, I/O pins, and bit names may use the generic designator ‘x’ to indicate the
use of a numeral to distinguish a particular module, when required.
21.1 CCP Module Configuration
Each Capture/Compare/PWM module is associated with a control register (CCPxCON), a capture input
selection register (CCPxCAP) and a data register (CCPRx). The data register, in turn, is comprised of two
8-bit registers: CCPRxL (low byte) and CCPRxH (high byte).
21.1.1 CCP Modules and Timer Resources
The CCP modules utilize Timers 1 through 6 that vary with the selected mode. Various timers are
available to the CCP modules in Capture, Compare or PWM modes, as shown in the table below.
Table 21-1. CCP Mode - Timer Resources
CCP Mode Timer Resource
Capture
Timer1, Timer3 or Timer5
Compare
PWM Timer2, Timer4 or Timer6
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 368
The assignment of a particular timer to a module is determined by the timer to CCP enable bits in the
CCPTMRS register. All of the modules may be active at once and may share the same timer resource if
they are configured to operate in the same mode (Capture/Compare or PWM) at the same time.
21.1.2 Open-Drain Output Option
When operating in Output mode (the Compare or PWM modes), the drivers for the CCPx pins can be
optionally configured as open-drain outputs. This feature allows the voltage level on the pin to be pulled
to a higher level through an external pull-up resistor and allows the output to communicate with external
circuits without the need for additional level shifters.
21.2 Capture Mode
Capture mode makes use of the 16-bit odd numbered timer resources (Timer1, Timer3, etc.). When an
event occurs on the capture source, the 16-bit CCPRx register captures and stores the 16-bit value of the
TMRx register. An event is defined as one of the following and is configured by the MODE bits:
Every falling edge of CCPx input
Every rising edge of CCPx input
Every 4th rising edge of CCPx input
Every 16th rising edge of CCPx input
Every edge of CCPx input (rising or falling)
When a capture is made, the Interrupt Request Flag bit CCPxIF of the PIRx register is set. The interrupt
flag must be cleared in software. If another capture occurs before the value in the CCPRx register is read,
the old captured value is overwritten by the new captured value.
Important:  If an event occurs during a 2-byte read, the high and low-byte data will be from
different events. It is recommended while reading the CCPRxH:CCPRxL register pair to either
disable the module or read the register pair twice for data integrity.
The following figure shows a simplified diagram of the capture operation.
Figure 21-1. Capture Mode Operation Block Diagram
Rev. 10-000158E
6/26/2017
CCPRxH CCPRxL
TMR1H TMR1L
16
16
Prescaler
1,4,16
CCPx
TRIS Control
set CCPxIF
CCPx MODE <3:0>
and
Edge Detect
RxyPPS
CTS PPS
PPS
CCPxPPS
Capture Trigger Sources
See CCPxCAP register
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 369
21.2.1 Capture Sources
In Capture mode, the CCPx pin should be configured as an input by setting the associated TRIS control
bit.
Important:  If the CCPx pin is configured as an output, a write to the port can cause a capture
condition.
The capture source is selected by configuring the CTS bits as shown in the following table:
Table 21-2. Capture Trigger Sources
CTS Source
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0100-0111 Reserved
0011 IOC Interrupt
0010 CMP2_output
0001 CMP1_output
0000 Pin selected by CCPxPPS
21.2.2 Timer1 Mode Resource
Timer1 must be running in Timer mode or Synchronized Counter mode for the CCP module to use the
capture feature. In Asynchronous Counter mode, the capture operation may not work.
See section "Timer1 Module with Gate Control" for more information on configuring Timer1.
Related Links
19. Timer1 Module with Gate Control
21.2.3 Software Interrupt Mode
When the Capture mode is changed, a false capture interrupt may be generated. The user should keep
the CCPxIE Interrupt Priority bit of the PIEx register clear to avoid false interrupts. Additionally, the user
should clear the CCPxIF interrupt flag bit of the PIRx register following any change in Operating mode.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 370
Important:  Clocking Timer1 from the system clock (FOSC) should not be used in Capture
mode. In order for Capture mode to recognize the trigger event on the CCPx pin, Timer1 must
be clocked from the instruction clock (FOSC/4) or from an external clock source.
21.2.4 CCP Prescaler
There are four prescaler settings specified by the MODE bits. Whenever the CCP module is turned off, or
the CCP module is not in Capture mode, the prescaler counter is cleared. Any Reset will clear the
prescaler counter.
Switching from one capture prescaler to another does not clear the prescaler and may generate a false
interrupt. To avoid this unexpected operation, turn the module off by clearing the CCPxCON register
before changing the prescaler. The example below demonstrates the code to perform this function.
Example 21-1. Changing Between Capture Prescalers
BANKSEL CCP1CON ;(only needed when CCP1CON is not in ACCESS space)
CLRF CCP1CON ;Turn CCP module off
MOVLW NEW_CAPT_PS ;CCP ON and Prescaler select → W
MOVWF CCP1CON ;Load CCP1CON with this value
21.2.5 Capture During Sleep
Capture mode depends upon the Timer1 module for proper operation. There are two options for driving
the Timer1 module in Capture mode. It can be driven by the instruction clock (FOSC/4), or by an external
clock source.
When Timer1 is clocked by FOSC/4, Timer1 will not increment during Sleep. When the device wakes from
Sleep, Timer1 will continue from its previous state.
Capture mode will operate during Sleep when Timer1 is clocked by an external clock source.
21.3 Compare Mode
The Compare mode function described in this section is available and identical for all CCP modules.
Compare mode makes use of the 16-bit odd numbered Timer resources (Timer1, Timer3, etc.). The 16-bit
value of the CCPRx register is constantly compared against the 16-bit value of the TMRx register. When
a match occurs, one of the following events can occur:
Toggle the CCPx output and clear TMRx
Toggle the CCPx output without clearing TMRx
Set the CCPx output
Clear the CCPx output
Pulse output
Pulse output and clear TMRx
The action on the pin is based on the value of the MODE control bits. At the same time, the interrupt flag
CCPxIF bit is set, and an ADC conversion can be triggered, if selected.
All Compare modes can generate an interrupt and trigger an ADC conversion. When MODE = '0001' or
'1011', the CCP resets the TMRx register.
The following figure shows a simplified diagram of the compare operation.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 371
Figure 21-2. Compare Mode Operation Block Diagram
CCPRxH CCPRxL
TMR1H TMR1L
Comparator
Q S
R
Output
Logic
PPS
RxyPPS
Set CCPxIF Interrupt Flag
4
TRIS
CCPx
Auto-conversion Trigger
MODE
Rev. 30-000133A
6/27/2017
21.3.1 CCPx Pin Configuration
The software must configure the CCPx pin as an output by clearing the associated TRIS bit and defining
the appropriate output pin through the RxyPPS registers. See section "Peripheral Pin Select (PPS)
Module" for more details.
The CCP output can also be used as an input for other peripherals.
Important:  Clearing the CCPxCON register will force the CCPx compare output latch to the
default low level. This is not the PORT I/O data latch.
Related Links
17. (PPS) Peripheral Pin Select Module
21.3.2 Timer1 Mode Resource
In Compare mode, Timer1 must be running in either Timer mode or Synchronized Counter mode. The
compare operation may not work in Asynchronous Counter mode.
See Section "Timer1 Module with Gate Control" for more information on configuring Timer1.
Important:  Clocking Timer1 from the system clock (FOSC) should not be used in Compare
mode. In order for Compare mode to generate the trigger event on the CCPx pin, Timer1 must
be clocked from the instruction clock (FOSC/4) or from an external clock source.
21.3.3 Auto-Conversion Trigger
All CCPx modes set the CCP Interrupt Flag (CCPxIF). When this flag is set and a match occurs, an auto-
conversion trigger can take place if the CCP module is selected as the conversion trigger source.
Refer to Section "Auto-Conversion Trigger" for more information.
Important:  Removing the match condition by changing the contents of the CCPRxH and
CCPRxL register pair, between the clock edge that generates the Auto-conversion Trigger and
the clock edge that generates the Timer1 Reset, will preclude the Reset from occurring.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 372
Related Links
32.2.6 Auto-Conversion Trigger
21.3.4 Compare During Sleep
Since FOSC is shut down during Sleep mode, the Compare mode will not function properly during Sleep,
unless the timer is running. The device will wake on interrupt (if enabled).
21.4 PWM Overview
Pulse-Width Modulation (PWM) is a scheme that provides power to a load by switching quickly between
fully ON and fully OFF states. The PWM signal resembles a square wave where the high portion of the
signal is considered the ON state and the low portion of the signal is considered the OFF state. The high
portion, also known as the pulse width, can vary in time and is defined in steps. A larger number of steps
applied, which lengthens the pulse width, also supplies more power to the load. Lowering the number of
steps applied, which shortens the pulse width, supplies less power. The PWM period is defined as the
duration of one complete cycle or the total amount of ON and OFF time combined.
PWM resolution defines the maximum number of steps that can be present in a single PWM period. A
higher resolution allows for more precise control of the pulse-width time and in turn the power that is
applied to the load.
The term duty cycle describes the proportion of the ON time to the OFF time and is expressed in
percentages, where 0% is fully OFF and 100% is fully ON. A lower duty cycle corresponds to less power
applied and a higher duty cycle corresponds to more power applied.
The figure below shows a typical waveform of the PWM signal.
Figure 21-3. CCP PWM Output Signal
Period
Pulse Width
TMR2 = 0
TMR2 = CCPRxH:CCPRxL
TMR2 = PR2
Rev. 30-000134A
5/9/2017
21.4.1 Standard PWM Operation
The standard PWM function described in this section is available and identical for all CCP modules.
The standard PWM mode generates a Pulse-Width Modulation (PWM) signal on the CCPx pin with up to
ten bits of resolution. The period, duty cycle, and resolution are controlled by the following registers:
Even numbered TxPR registers (T2PR, T4PR, etc)
Even numbered TxCON registers (T2CON, T4CON, etc)
16-bit CCPRx registers
CCPxCON registers
It is required to have FOSC/4 as the clock input to TxTMR for correct PWM operation. The following figure
shows a simplified block diagram of PWM operation.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 373
Figure 21-4. Simplified PWM Block Diagram
Rev. 10-000 157C
9/5/201 4
CCPRxH
Duty cycle registers
10-bit Latch(2)
(Not accessible by user)
Comparator
Comparator
PR2
(1)
TMR2
TMR2 Module
CCPx
CCPx_out To Peripherals
R
TRIS Control
R
S
Q
CCPRxL
set CCPIF
CCPx_pset
ERS logic
PPS
RxyPPS
Note: 
1. 8-bit timer is concatenated with two bits generated by FOSC or two bits of the internal prescaler to
create 10-bit time base.
2. The alignment of the 10 bits from the CCPRx register is determined by the CCPxFMT bit.
Important:  The corresponding TRIS bit must be cleared to enable the PWM output on the
CCPx pin.
21.4.2 Setup for PWM Operation
The following steps should be taken when configuring the CCP module for standard PWM operation:
1. Use the desired output pin RxyPPS control to select CCPx as the source and disable the CCPx pin
output driver by setting the associated TRIS bit.
2. Load the T2PR register with the PWM period value.
3. Configure the CCP module for the PWM mode by loading the CCPxCON register with the
appropriate values.
4. Load the CCPRx register with the PWM duty cycle value and configure the FMT bit to set the
proper register alignment.
5. Configure and start Timer2:
Clear the TMR2IF interrupt flag bit of the PIRx register. See Note below.
Select the timer clock source to be as FOSC/4 using the TxCLKCON register. This is required
for correct operation of the PWM module.
Configure the T2CKPS bits of the T2CON register with the timer prescale value.
Enable the timer by setting the T2ON bit.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 374
6. Enable PWM output pin:
Wait until the timer overflows and the TMR2IF bit of the PIRx register is set. See Note below.
Enable the CCPx pin output driver by clearing the associated TRIS bit.
Important:  In order to send a complete duty cycle and period on the first PWM
output, the above steps must be included in the setup sequence. If it is not critical to
start with a complete PWM signal on the first output, then step 6 may be ignored.
Related Links
20.9.3 TxCON
21.4.3 Timer2 Timer Resource
The PWM standard mode makes use of the 8-bit Timer2 timer resources to specify the PWM period.
21.4.4 PWM Period
The PWM period is specified by the T2PR register of Timer2. The PWM period can be calculated using
the formula in the equation below.
Figure 21-5. PWM Period
 =2 + 1 4  2Pr
where TOSC = 1/FOSC
When T2TMR is equal to T2PR, the following three events occur on the next increment cycle:
T2TMR is cleared
The CCPx pin is set. (Exception: If the PWM duty cycle = 0%, the pin will not be set.)
The PWM duty cycle is transferred from the CCPRx register into a 10-bit buffer.
Important:  The Timer postscaler (see "Timer2 Interrupt") is not used in the determination of
the PWM frequency.
Related Links
20.4 Timer2 Interrupt
21.4.5 PWM Duty Cycle
The PWM duty cycle is specified by writing a 10-bit value to the CCPRx register. The alignment of the 10-
bit value is determined by the FMT bit (see Figure 21-6). The CCPRx register can be written to at any
time. However, the duty cycle value is not latched into the 10-bit buffer until after a match between T2PR
and T2TMR.
The equations below are used to calculate the PWM pulse width and the PWM duty cycle ratio.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 375
Figure 21-6. PWM 10-Bit Alignment
Rev. 10-000 160A
12/9/201 3
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
CCPRxH CCPRxL
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
CCPRxH CCPRxL
FMT = 0
FMT = 1
7 6 5 4 3 2 1 09 8
10-bit Duty Cycle
Figure 21-7. Pulse Width
  = :    2 Pr 
Figure 21-8. Duty Cycle
 =:  
42 + 1
The CCPRx register is used to double buffer the PWM duty cycle. This double buffering is essential for
glitchless PWM operation.
The 8-bit timer T2TMR register is concatenated with either the 2-bit internal system clock (FOSC), or two
bits of the prescaler, to create the 10-bit time base. The system clock is used if the Timer2 prescaler is set
to 1:1.
When the 10-bit time base matches the CCPRx register, then the CCPx pin is cleared (see Figure 21-4).
21.4.6 PWM Resolution
The resolution determines the number of available duty cycles for a given period. For example, a 10-bit
resolution will result in 1024 discrete duty cycles, whereas an 8-bit resolution will result in 256 discrete
duty cycles.
The maximum PWM resolution is ten bits when T2PR is 255. The resolution is a function of the T2PR
register value as shown below.
Figure 21-9. PWM Resolution
Re =log 4 2 + 1
log 2 
Important:  If the pulse-width value is greater than the period, the assigned PWM pin(s) will
remain unchanged.
Table 21-3. Example PWM Frequencies and Resolutions (FOSC = 20 MHz)
PWM Frequency 1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
Timer Prescale 16 4 1 1 1 1
T2PR Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 10 10 10 8 7 6.6
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 376
Table 21-4. Example PWM Frequencies and Resolutions (FOSC = 8 MHz)
PWM Frequency 1.22 kHz 4.90 kHz 19.61 kHz 76.92 kHz 153.85 kHz 200.0 kHz
Timer Prescale 16 4 1 1 1 1
T2PR Value 0x65 0x65 0x65 0x19 0x0C 0x09
Maximum Resolution (bits) 8 8 8 6 5 5
21.4.7 Operation in Sleep Mode
In Sleep mode, the T2TMR register will not increment and the state of the module will not change. If the
CCPx pin is driving a value, it will continue to drive that value. When the device wakes up, T2TMR will
continue from the previous state.
21.4.8 Changes in System Clock Frequency
The PWM frequency is derived from the system clock frequency. Any changes in the system clock
frequency will result in changes to the PWM frequency. See the "Oscillator Module (with Fail-Safe Clock
Monitor)" section for additional details.
Related Links
4. Oscillator Module (with Fail-Safe Clock Monitor)
21.4.9 Effects of Reset
Any Reset will force all ports to Input mode and the CCP registers to their Reset states.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 377
21.5 Register Summary - CCP Control
Address Name Bit Pos.
0x0FA5 CCPR2
7:0 CCPRL[7:0]
15:8 CCPRH[7:0]
0x0FA7 CCP2CON 7:0 EN OUT FMT MODE[3:0]
0x0FA8 CCP2CAP 7:0 CTS[3:0]
0x0FA9 CCPR1
7:0 CCPRL[7:0]
15:8 CCPRH[7:0]
0x0FAB CCP1CON 7:0 EN OUT FMT MODE[3:0]
0x0FAC CCP1CAP 7:0 CTS[3:0]
0x0FAD CCPTMRS 7:0 P4TSEL[1:0] P3TSEL[1:0] C2TSEL[1:0] C1TSEL[1:0]
21.6 Register Definitions: CCP Control
Long bit name prefixes for the CCP peripherals are shown in the following table. Refer to the “Long Bit
Names” section for more information.
Table 21-5. CCP Long bit name prefixes
Peripheral Bit Name Prefix
CCP1 CCP1
CCP2 CCP2
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 378
21.6.1 CCPxCON
Name:  CCPxCON
Address:  0xFAB,0xFA7
CCP Control Register
Bit 7 6 5 4 3 2 1 0
EN OUT FMT MODE[3:0]
Access R/W RO R/W R/W R/W R/W R/W
Reset 0 x 0 0 0 0 0
Bit 7 – EN CCP Module Enable bit
Value Description
1CCP is enabled
0CCP is disabled
Bit 5 – OUT CCP Output Data bit (read-only)
Bit 4 – FMT CCPW (pulse-width) Value Alignment bit
Value Condition Description
xCapture mode Not used
xCompare mode Not used
1PWM mode Left-aligned format
0PWM mode Right-aligned format
Bits 3:0 – MODE[3:0] CCP Mode Select bits
Table 21-6. CCPx Mode Select Bits
MODE Operating Mode Operation Set CCPxIF
11xx PWM PWM Operation Yes
1011 Compare Pulse output; clear TMR1(2) Yes
1010 Pulse output Yes
1001 Clear output(1) Yes
1000 Set output(1) Yes
0111 Capture Every 16th rising edge of CCPx input Yes
0110 Every 4th rising edge of CCPx input Yes
0101 Every rising edge of CCPx input Yes
0100 Every falling edge of CCPx input Yes
0011 Every edge of CCPx input Yes
0010 Compare Toggle output Yes
0001 Toggle output; clear TMR1(2) Yes
0000 Disabled
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 379
Note: 
1. The set and clear operations of the Compare mode are Reset by setting MODE = '0000'.
2. When MODE = '0001' or '1011', then the timer associated with the CCP module is cleared.
TMR1 is the default selection for the CCP module, so it is used for indication purpose only.
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 380
21.6.2 CCPxCAP
Name:  CCPxCAP
Address:  0xFAC,0xFA8
Capture Trigger Input Selection Register
Bit 7 6 5 4 3 2 1 0
CTS[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – CTS[3:0] Capture Trigger Input Selection bits
Table 21-7. Capture Trigger Sources
CTS Source
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0100-0111 Reserved
0011 IOC Interrupt
0010 CMP2_output
0001 CMP1_output
0000 Pin selected by CCPxPPS
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 381
21.6.3 CCPRx
Name:  CCPRx
Address:  0xFA9,0xFA5
Capture/Compare/Pulse Width Register
Bit 15 14 13 12 11 10 9 8
CCPRH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
CCPRL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 15:8 – CCPRH[7:0]
Capture/Compare/Pulse Width High byte
Value Condition Description
0 to
255
MODE = Capture High byte of 16-bit captured value
0 to
255
MODE = Compare High byte of 16-bit compare value
0,1,2,3 MODE = PWM and FMT=0CCPRH<1:0>=Bits<9:8> of 10-bit Pulse width value
CCPRH<7:2> not used
0 to
255
MODE = PWM and FMT=1Bits<9:2> of 10-bit Pulse width value
Bits 7:0 – CCPRL[7:0]
Capture/Compare/Pulse Width Low byte
Value Condition Description
0 to
255
MODE = Capture Low byte of 16-bit captured value
0 to
255
MODE = Compare Low byte of 16-bit compare value
0 to
255
MODE = PWM and FMT=0Bits<7:0> of 10-bit Pulse width value
0,64,12
8,192
MODE = PWM and FMT=1CCPRL<7:6>=Bits<1:0> of 10-bit Pulse width value
CCPRL<5:0> not used
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 382
21.6.4 CCPTMRS
Name:  CCPTMRS
Address:  0xFAD
CCP Timers Control Register
Bit 7 6 5 4 3 2 1 0
P4TSEL[1:0] P3TSEL[1:0] C2TSEL[1:0] C1TSEL[1:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 1 0 1 0 1 0 1
Bits 4:5, 6:7 – PnTSEL PWMn Timer Selection bits
Value Description
11 PWMn based on Timer6
10 PWMn based on Timer4
01 PWMn based on Timer2
00 Reserved
Bits 0:1, 2:3 – CnTSEL CCPn Timer Selection bits
Value Description
11 CCPn is based off Timer5 in Capture/Compare mode and Timer6 in PWM mode
10 CCPn is based off Timer3 in Capture/Compare mode and Timer4 in PWM mode
01 CCPn is based off Timer1 in Capture/Compare mode and Timer2 in PWM mode
00 Reserved
PIC18F26/45/46Q10
Capture/Compare/PWM Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 383
22. (PWM) Pulse-Width Modulation
The PWM module generates a Pulse-Width Modulated signal determined by the duty cycle, period, and
resolution that are configured by the following registers:
TxPR
TxCON
PWMxDC
PWMxCON
Important:  The corresponding TRIS bit must be cleared to enable the PWM output on the
PWMx pin.
Each PWM module can select the timer source that controls the module. Each module has an
independent timer selection which can be accessed using the CCPTMRS register. Note that the PWM
mode operation is described with respect to TMR2 in the following sections.
Figure 22-1 shows a simplified block diagram of PWM operation.
Figure 22-2 shows a typical waveform of the PWM signal.
Figure 22-1. Simplified PWM Block Diagram
PWMxDCH
Comparator
TMR2
Comparator
PR2
(1)
R Q
S
Duty Cycle registers PWMxDCL<7:6>
Clear Timer,
PWMx pin and
latch Duty Cycle
PWMx
Note 1: 8-bit timer is concatenated with the two Least Significant bits of 1/FOSC adjusted by the Timer2 prescaler to
create a 10-bit time base.
Latched
(Not visible to user)
Q
Output Polarity (PWMxPOL)
TMR2 Module
0
1
PWMxOUT
to other peripherals
PPS
RxyPPS
Rev. 30-000130A
5/17/2017
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 384
Figure 22-2. PWM Output
Period
Pulse Width
TMR2 = 0
TMR2 =
TMR2 = PR2
PWMxDCH<7:0>:PWMxDCL<7:6>
Rev. 30-000129A
5/17/2017
For a step-by-step procedure on how to set up this module for PWM operation, refer to 22.9 Setup for
PWM Operation using PWMx Output Pins.
22.1 Fundamental Operation
The PWM module produces a 10-bit resolution output. The PWM timer can be selected using the
PxTSEL bits in the CCPTMRS register. The default selection for PWMx is TMR2. Note that the PWM
module operation in the following sections is described with respect to TMR2. Timer2 and T2PR set the
period of the PWM. The PWMxDCL and PWMxDCH registers configure the duty cycle. The period is
common to all PWM modules, whereas the duty cycle is independently controlled.
Important:  The Timer2 postscaler is not used in the determination of the PWM frequency. The
postscaler could be used to have a servo update rate at a different frequency than the PWM
output.
All PWM outputs associated with Timer2 are set when T2TMR is cleared. Each PWMx is cleared when
TxTMR is equal to the value specified in the corresponding PWMxDCH (8 MSb) and PWMxDCL<7:6> (2
LSb) registers. When the value is greater than or equal to T2PR, the PWM output is never cleared (100%
duty cycle).
Important:  The PWMxDCH and PWMxDCL registers are double-buffered. The buffers are
updated when T2TMR matches T2PR. Care should be taken to update both registers before the
timer match occurs.
22.2 PWM Output Polarity
The output polarity is inverted by setting the POL bit.
22.3 PWM Period
The PWM period is specified by the TxPR register The PWM period can be calculated using the formula
of 22.3 PWM Period. It is required to have FOSC/4 as the selected clock input to the timer for correct
PWM operation.
Figure 22-3. PWM Period
 =2 + 1 4  2 Pr
Note:  TOSC = 1/FOSC
When T2TMR is equal to T2PR, the following three events occur on the next increment cycle:
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 385
T2TMR is cleared
The PWM output is active. (Exception: When the PWM duty cycle = 0%, the PWM output will remain
inactive.)
The PWMxDCH and PWMxDCL register values are latched into the buffers.
Important:  The Timer2 postscaler has no effect on the PWM operation.
22.4 PWM Duty Cycle
The PWM duty cycle is specified by writing a 10-bit value to the PWMxDCH and PWMxDCL register pair.
The PWMxDCH register contains the eight MSbs and the PWMxDCL<7:6>, the two LSbs. The
PWMxDCH and PWMxDCL registers can be written to at any time.
The formulas below are used to calculate the PWM pulse width and the PWM duty cycle ratio.
Figure 22-4. Pulse Width
 = : < 7: 6 >  2Pr
Note:  TOSC = 1/FOSC
Figure 22-5. Duty Cycle Ratio
 =: < 7:6 >
42 + 1
The 8-bit timer T2TMR register is concatenated with the two Least Significant bits of 1/FOSC, adjusted by
the Timer2 prescaler to create the 10-bit time base. The system clock is used if the Timer2 prescaler is
set to 1:1.
22.5 PWM Resolution
The resolution determines the number of available duty cycles for a given period. For example, a 10-bit
resolution will result in 1024 discrete duty cycles, whereas an 8-bit resolution will result in 256 discrete
duty cycles.
The maximum PWM resolution is ten bits when T2PR is 255. The resolution is a function of the T2PR
register value as shown below.
Figure 22-6. PWM Resolution
Re =log 4 2 + 1
log 2 
Important:  If the pulse-width value is greater than the period, the assigned PWM pin(s) will
remain unchanged.
Table 22-1. Example PWM Frequencies and Resolutions (FOSC = 20 MHz)
PWM Frequency 0.31 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
Timer Prescale 64 4 1 1 1 1
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 386
...........continued
PWM Frequency 0.31 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
T2PR Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 10 10 10 8 7 6.6
Table 22-2. Example PWM Frequencies and Resolutions (FOSC = 8 MHz)
PWM Frequency 0.31 kHz 4.90 kHz 19.61 kHz 76.92 kHz 153.85 kHz 200.0 kHz
Timer Prescale 64 4 1 1 1 1
T2PR Value 0x65 0x65 0x65 0x19 0x0C 0x09
Maximum Resolution (bits) 8 8 8 6 5 5
22.6 Operation in Sleep Mode
In Sleep mode, the T2TMR register will not increment and the state of the module will not change. If the
PWMx pin is driving a value, it will continue to drive that value. When the device wakes up, T2TMR will
continue from its previous state.
22.7 Changes in System Clock Frequency
The PWM frequency is derived from the system clock frequency (FOSC). Any changes in the system clock
frequency will result in changes to the PWM frequency.
Related Links
4. Oscillator Module (with Fail-Safe Clock Monitor)
22.8 Effects of Reset
Any Reset will force all ports to Input mode and the PWM registers to their Reset states.
22.9 Setup for PWM Operation using PWMx Output Pins
The following steps should be taken when configuring the module for PWM operation using the PWMx
pins:
1. Disable the PWMx pin output driver(s) by setting the associated TRIS bit(s).
2. Clear the PWMxCON register.
3. Load the T2PR register with the PWM period value.
4. Load the PWMxDCH register and bits <7:6> of the PWMxDCL register with the PWM duty cycle
value.
5. Configure and start Timer2:
Clear the TMR2IF interrupt flag bit of the PIRx register.(1)
Select the timer clock source to be as FOSC/4 using the TxCLKCON register. This is required
for correct operation of the PWM module.
Configure the T2CKPS bits of the T2CON register with the Timer2 prescale value.
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 387
Enable Timer2 by setting the T2ON bit of the T2CON register.
6. Enable PWM output pin and wait until Timer2 overflows, TMR2IF bit of the PIRx register is set.(2)
7. Enable the PWMx pin output driver(s) by clearing the associated TRIS bit(s) and setting the desired
pin PPS control bits.
8. Configure the PWM module by loading the PWMxCON register with the appropriate values.
Note: 
1. In order to send a complete duty cycle and period on the first PWM output, the above steps must
be followed in the order given. If it is not critical to start with a complete PWM signal, then move
Step 8 to replace Step 4.
2. For operation with other peripherals only, disable PWMx pin outputs.
22.9.1 PWMx Pin Configuration
All PWM outputs are multiplexed with the PORT data latch. The user must configure the pins as outputs
by clearing the associated TRIS bits.
22.10 Setup for PWM Operation to Other Device Peripherals
The following steps should be taken when configuring the module for PWM operation to be used by other
device peripherals:
1. Disable the PWMx pin output driver(s) by setting the associated TRIS bit(s).
2. Clear the PWMxCON register.
3. Load the T2PR register with the PWM period value.
4. Load the PWMxDCH register and bits <7:6> of the PWMxDCL register with the PWM duty cycle
value.
5. Configure and start Timer2:
Clear the TMR2IF interrupt flag bit of the PIRx register.(1)
Select the timer clock source to be as FOSC/4 using the TxCLKCON register. This is required
for correct operation of the PWM module.
Configure the T2CKPS bits of the T2CON register with the Timer2 prescale value.
Enable Timer2 by setting the T2ON bit of the T2CON register.
6. Wait until Timer2 overflows, TMR2IF bit of the PIRx register is set.(1)
7. Configure the PWM module by loading the PWMxCON register with the appropriate values.
Note: 
1. In order to send a complete duty cycle and period on the first PWM output, the above steps must
be included in the setup sequence. If it is not critical to start with a complete PWM signal on the first
output, then step 6 may be ignored.
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 388
22.11 Register Summary - Registers Associated with PWM
Address Name Bit Pos.
0x0F9F PWM4DC
7:0 DCL[1:0]
15:8 DCH[7:0]
0x0FA1 PWM4CON 7:0 EN OUT POL
0x0FA2 PWM3DC
7:0 DCL[1:0]
15:8 DCH[7:0]
0x0FA4 PWM3CON 7:0 EN OUT POL
0x0FA5
...
0x0FAC
Reserved
0x0FAD CCPTMRS 7:0 P4TSEL[1:0] P3TSEL[1:0] C2TSEL[1:0] C1TSEL[1:0]
22.12 Register Definitions: PWM Control
Long bit name prefixes for the PWM peripherals are shown in the table below. Refer to the "Long Bit
Names Section" for more information.
Table 22-3. PWM Bit Name Prefixes
Peripheral Bit Name Prefix
PWM3 PWM3
PWM4 PWM4
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 389
22.12.1 PWMxCON
Name:  PWMxCON
Address:  0xFA4,0xFA1
PWM Control Register
Bit 7 6 5 4 3 2 1 0
EN OUT POL
Access R/W RO R/W
Reset 0 0 0
Bit 7 – EN PWM Module Enable bit
Value Description
1PWM module is enabled
0PWM module is disabled
Bit 5 – OUT PWM Module Output Level When Bit is Read
Bit 4 – POL PWM Output Polarity Select bit
Value Description
1PWM output is inverted
0PWM output is normal
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 390
22.12.2 CCPTMRS
Name:  CCPTMRS
Address:  0xFAD
CCP Timers Control Register
Bit 7 6 5 4 3 2 1 0
P4TSEL[1:0] P3TSEL[1:0] C2TSEL[1:0] C1TSEL[1:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 1 0 1 0 1 0 1
Bits 7:6 – P4TSEL[1:0] PWM4 Timer Selection bits
Value Description
11 PWM4 based on TMR6
10 PWM4 based on TMR4
01 PWM4 based on TMR2
00 Reserved
Bits 5:4 – P3TSEL[1:0] PWM3 Timer Selection bits
Value Description
11 PWM3 based on TMR6
10 PWM3 based on TMR4
01 PWM3 based on TMR2
00 Reserved
Bits 3:2 – C2TSEL[1:0] CCP2 Timer Selection bits
Value Description
11 CCP2 is based off Timer5 in Capture/Compare mode and Timer6 in PWM mode
10 CCP2 is based off Timer3 in Capture/Compare mode and Timer4 in PWM mode
01 CCP2 is based off Timer1 in Capture/Compare mode and Timer2 in PWM mode
00 Reserved
Bits 1:0 – C1TSEL[1:0] CCP1 Timer Selection bits
Value Description
11 CCP1 is based off Timer5 in Capture/Compare mode and Timer6 in PWM mode
10 CCP1 is based off Timer3 in Capture/Compare mode and Timer4 in PWM mode
01 CCP1 is based off Timer1 in Capture/Compare mode and Timer2 in PWM mode
00 Reserved
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 391
22.12.3 PWMxDC
Name:  PWMxDC
Address:  0xFA2,0xF9F
PWM Duty Cycle Register
Bit 15 14 13 12 11 10 9 8
DCH[7:0]
Access
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
DCL[1:0]
Access
Reset x x
Bits 15:8 – DCH[7:0] PWM Duty Cycle Most Significant bits
These bits are the MSbs of the PWM duty cycle.
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
Bits 7:6 – DCL[1:0] PWM Duty Cycle Least Significant bits
These bits are the LSbs of the PWM duty cycle.
Reset States: POR/BOR = xx
All Other Resets = uu
PIC18F26/45/46Q10
(PWM) Pulse-Width Modulation
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 392
23. (ZCD) Zero-Cross Detection Module
The ZCD module detects when an A/C signal crosses through the ground potential. The actual zero
crossing threshold is the zero crossing reference voltage, ZCPINV, which is typically 0.75V above ground.
The connection to the signal to be detected is through a series current-limiting resistor. The module
applies a current source or sink to the ZCD pin to maintain a constant voltage on the pin, thereby
preventing the pin voltage from forward biasing the ESD protection diodes. When the applied voltage is
greater than the reference voltage, the module sinks current. When the applied voltage is less than the
reference voltage, the module sources current. The current source and sink action keeps the pin voltage
constant over the full range of the applied voltage. The ZCD module is shown in the following simplified
block diagram.
Figure 23-1. Simplified ZCD Block Diagram
Filename: 10-000194B.vsd
Title: ZERO CROSS DETECT BLOCK DIAGRAM
Last Edit: 5/14/2014
First Used: PIC16(L)F1615
Notes:
Rev. 10-000194B
5/14/2014
-
+
Zcpinv
VDD
ZCDxIN
VPULLUP
External
voltage
source
RPULLDOWN
optional
optional
RPULLUP
ZCDxPOL
D Q
ZCDx_output
ZCDxOUT bit
Q1
ZCDxINTP
ZCDxINTN
Interrupt
det
Interrupt
det
Set
ZCDIF
flag
RSERIES
The ZCD module is useful when monitoring an A/C waveform for, but not limited to, the following
purposes:
A/C period measurement
Accurate long term time measurement
Dimmer phase delayed drive
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 393
Low EMI cycle switching
23.1 External Resistor Selection
The ZCD module requires a current-limiting resistor in series with the external voltage source. The
impedance and rating of this resistor depends on the external source peak voltage. Select a resistor
value that will drop all of the peak voltage when the current through the resistor is nominally 300 μA.
Make sure that the ZCD I/O pin internal weak pull-up is disabled so it does not interfere with the current
source and sink.
Figure 23-2. External Resistor
 =
3 × 104
Figure 23-3. External Voltage Source
VPEAK
ZCPINV
VMAXPEAK
VMINPEAK
Rev. 30-000001A
7/18/2017
23.2 ZCD Logic Output
The ZCD module includes a Status bit, which can be read to determine whether the current source or
sink is active. The OUT bit is set when the current sink is active, and cleared when the current source is
active. The OUT bit is affected by the polarity bit.
The OUT signal can also be used as input to other modules. This is controlled by the registers of the
corresponding module. OUT can be used as follows:
Gate source for TMR1/3/5
Clock source for TMR2/4/6
Reset source for TMR2/4/6
23.3 ZCD Logic Polarity
The POL bit inverts the OUT bit relative to the current source and sink output. When the POL bit is set, a
OUT high indicates that the current source is active, and a low output indicates that the current sink is
active.
The POL bit affects the ZCD interrupts.
23.4 ZCD Interrupts
An interrupt will be generated upon a change in the ZCD logic output when the appropriate interrupt
enables are set. A rising edge detector and a falling edge detector are present in the ZCD for this
purpose.
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 394
The ZCDIF bit of the PIRx register will be set when either edge detector is triggered and its associated
enable bit is set. The INTP enables rising edge interrupts and the INTN bit enables falling edge interrupts.
Priority of the interrupt can be changed if the IPEN bit of the INTCON register is set. The ZCD interrupt
can be made high or low priority by setting or clearing the ZCDIP bit of the IPRx register.
To fully enable the interrupt, the following bits must be set:
ZCDIE bit of the PIEx register
INTP bit for rising edge detection
INTN bit for falling edge detection
PEIE and GIE bits of the INTCON register
Changing the POL bit will cause an interrupt, regardless of the level of the SEN bit.
The ZCDIF bit of the PIRx register must be cleared in software as part of the interrupt service. If another
edge is detected while this flag is being cleared, the flag will still be set at the end of the sequence.
23.5 Correction for ZCPINV Offset
The actual voltage at which the ZCD switches is the reference voltage at the non-inverting input of the
ZCD op amp. For external voltage source waveforms other than square waves, this voltage offset from
zero causes the zero-cross event to occur either too early or too late.
23.5.1 Correction by AC Coupling
When the external voltage source is sinusoidal, the effects of the ZCPINV offset can be eliminated by
isolating the external voltage source from the ZCD pin with a capacitor, in addition to the voltage reducing
resistor. The capacitor will cause a phase shift resulting in the ZCD output switch in advance of the actual
zero crossing event. The phase shift will be the same for both rising and falling zero crossings, which can
be compensated for by either delaying the CPU response to the ZCD switch by a timer or other means, or
selecting a capacitor value large enough that the phase shift is negligible.
To determine the series resistor and capacitor values for this configuration, start by computing the
impedance, Z, to obtain a peak current of 300 μA. Next, arbitrarily select a suitably large non-polar
capacitor and compute its reactance, Xc, at the external voltage source frequency. Finally, compute the
series resistor, capacitor peak voltage, and phase shift by the formulas shown below.
When this technique is used and the input signal is not present, the ZCD will tend to oscillate. To avoid
this oscillation, connect the ZCD pin to VDD or GND with a high-impedance resistor such as 200K.
Figure 23-4. R-C Equations
VPEAK = external voltage source peak voltage
f = external voltage source frequency
C = series capacitor
R = series resistor
VC = Peak capacitor voltage
Φ = Capacitor induced zero crossing phase advance in radians
TΦ = Time ZC event occurs before actual zero crossing
=
3 × 104
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 395
=1
2
=2 2
=3 × 104
Φ = tan 1
Φ=Φ
2
Figure 23-5. R-C Calcuation Example
 = 120
 = × 2 = 169.7
= 60 
= 0.1 
=
3 × 104=169.7
3 × 104= 565.7 Ω
=1
2 =1
2× 60 × 107= 26.53 Ω
=2 2= 565.1 Ω
= 560 Ω
=2+2= 560.6 Ω
 =
= 302.7 × 106
=× = 8.0
Φ = tan 1
= 0.047
Φ=Φ
2 = 125.6
23.5.2 Correction By Offset Current
When the waveform is varying relative to VSS, then the zero cross is detected too early as the waveform
falls and too late as the waveform rises. When the waveform is varying relative to VDD, then the zero
cross is detected too late as the waveform rises and too early as the waveform falls. The actual offset
time can be determined for sinusoidal waveforms with the corresponding equations shown below.
Figure 23-6. ZCD Event Offset
When External Voltage source is relative to VSS
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 396
 =
sin1

2
When External Voltage source is relative to VDD
 =
sin1 

2
This offset time can be compensated for by adding a pull-up or pull-down biasing resistor to the ZCD pin.
A pull-up resistor is used when the external voltage source is varying relative to VSS. A pull-down resistor
is used when the voltage is varying relative to VDD. The resistor adds a bias to the ZCD pin so that the
target external voltage source must go to zero to pull the pin voltage to the ZCPINV switching voltage. The
pull-up or pull-down value can be determined with the equations shown below.
Figure 23-7. ZCD Pull-up/Pull-down Resistor
When External Voltage source is relative to VSS
 =  

When External Voltage source is relative to VDD
 = 
 
23.6 Handling VPEAK Variations
If the peak amplitude of the external voltage is expected to vary, the series resistor must be selected to
keep the ZCD current source and sink below the design maximum range of ± 600 μA and above a
reasonable minimum range. A general rule of thumb is that the maximum peak voltage can be no more
than six times the minimum peak voltage. To ensure that the maximum current does not exceed ± 600 μA
and the minimum is at least ± 100 μA, compute the series resistance as shown in Figure 23-8. The
compensating pull-up for this series resistance can be determined with the equations shown in Figure
23-7 because the pull-up value is independent from the peak voltage.
Figure 23-8. Series R for V range
 =_ +_
7 × 104
23.7 Operation During Sleep
The ZCD current sources and interrupts are unaffected by Sleep.
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 397
23.8 Effects of a Reset
The ZCD circuit can be configured to default to the Active or Inactive state on Power-on Reset (POR).
When the ZCD Configuration bit is cleared, the ZCD circuit will be active at POR. When the ZCD
Configuration bit is set, the SEN bit must be set to enable the ZCD module.
23.9 Disabling the ZCD Module
The ZCD module can be disabled in two ways:
1. The ZCD Configuration bit disables the ZCD module when set. When this is the case then the ZCD
module will be enabled by setting the SEN bit. When the ZCD bit is clear, the ZCD is always
enabled and the SEN bit has no effect.
2. The ZCD can also be disabled using the ZCDMD bit of the PMDx register. This is subject to the
status of the ZCD bit.
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 398
23.10 Register Summary: ZCD Control
Address Name Bit Pos.
0x0F2D ZCDCON 7:0 SEN OUT POL INTP INTN
23.11 Register Definitions: ZCD Control
Long bit name prefixes for the ZCD peripherals are shown in the table below. Refer to the "Long Bit
Names Section" for more information.
Table 23-1. ZCD Long Bit Name Prefixes
Peripheral Bit Name Prefix
ZCD ZCD
Related Links
1.4.2.2 Long Bit Names
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 399
23.11.1 ZCDCON
Name:  ZCDCON
Address:  0xF2D
Zero-Cross Detect Control Register
Bit 7 6 5 4 3 2 1 0
SEN OUT POL INTP INTN
Access R/W RO R/W R/W R/W
Reset 0 x 0 0 0
Bit 7 – SEN Zero-Cross Detect Software Enable bit
This bit is ignored when ZCD fuse is cleared.
Value Condition Description
XZCD Config fuse = 0Zero-cross detect is always enabled. This bit is ignored.
1ZCD Config fuse = 1Zero-cross detect is enabled. ZCD pin is forced to output to source
and sink current.
0ZCD Config fuse = 1Zero-cross detect is disabled. ZCD pin operates according to PPS and
TRIS controls.
Bit 5 – OUT Zero-Cross Detect Data Output bit
Value Condition Description
1POL = 0ZCD pin is sinking current
0POL = 0ZCD pin is sourcing current
1POL = 1ZCD pin is sourcing current
0POL = 1ZCD pin is sinking current
Bit 4 – POL Zero-Cross Detect Polarity bit
Value Description
1ZCD logic output is inverted
0ZCD logic output is not inverted
Bit 1 – INTP Zero-Cross Detect Positive-Going Edge Interrupt Enable bit
Value Description
1ZCDIF bit is set on low-to-high ZCD_output transition
0ZCDIF bit is unaffected by low-to-high ZCD_output transition
Bit 0 – INTN Zero-Cross Detect Negative-Going Edge Interrupt Enable bit
Value Description
1ZCDIF bit is set on high-to-low ZCD_output transition
0ZCDIF bit is unaffected by high-to-low ZCD_output transition
PIC18F26/45/46Q10
(ZCD) Zero-Cross Detection Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 400
24. (CWG) Complementary Waveform Generator Module
The Complementary Waveform Generator (CWG) produces half-bridge, full-bridge, and steering of PWM
waveforms. It is backwards compatible with previous CCP functions. The PIC18F26/45/46Q10 family has
1 instance(s) of the CWG module.
The CWG has the following features:
Six Operating modes:
Synchronous Steering mode
Asynchronous Steering mode
Full-Bridge mode, Forward
Full-Bridge mode, Reverse
Half-Bridge mode
Push-Pull mode
Output Polarity Control
Output Steering
Independent 6-Bit Rising and Falling Event Dead-Band Timers:
Clocked dead band
Independent rising and falling dead-band enables
Auto-Shutdown Control With:
Selectable shutdown sources
Auto-restart option
Auto-shutdown pin override control
24.1 Fundamental Operation
The CWG generates two output waveforms from the selected input source.
The off-to-on transition of each output can be delayed from the on-to-off transition of the other output,
thereby, creating a time delay immediately where neither output is driven. This is referred to as dead time
and is covered in 24.7 Dead-Band Control.
It may be necessary to guard against the possibility of circuit faults or a feedback event arriving too late or
not at all. In this case, the active drive must be terminated before the Fault condition causes damage.
This is referred to as auto-shutdown and is covered in 24.11 Auto-Shutdown.
24.2 Operating Modes
The CWG module can operate in six different modes, as specified by the MODE bits:
Half-Bridge mode
Push-Pull mode
Asynchronous Steering mode
Synchronous Steering mode
Full-Bridge mode, Forward
Full-Bridge mode, Reverse
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 401
All modes accept a single pulse data input, and provide up to four outputs as described in the following
sections.
All modes include auto-shutdown control as described in 24.11 Auto-Shutdown
Important:  Except as noted for Full-Bridge mode (24.2.3 Full-Bridge Modes), mode changes
should only be performed while EN = 0.
24.2.1 Half-Bridge Mode
In Half-Bridge mode, two output signals are generated as true and inverted versions of the input as
illustrated in Figure 24-1. A non-overlap (dead-band) time is inserted between the two outputs to prevent
shoot-through current in various power supply applications. Dead-band control is described in 24.7
Dead-Band Control. The output steering feature cannot be used in this mode. A basic block diagram of
this mode is shown in Figure 24-2.
The unused outputs CWGxC and CWGxD drive similar signals, with polarity independently controlled by
the POLC and POLD bits, respectively.
Figure 24-1. CWG Half-Bridge Mode Operation
Rising Event D
Falling Event Dead Band
Rising Event Dead Band
Falling Event Dead Band
CWGx_clock
CWGxA
CWGxB
CWGx_data
CWGxC
CWGxD
Rev. 30-000097A
4/14/2017
Note:  CWGx_rising_src = CCP1_out, CWGx_falling_src = ~CCP1_out
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 402
Figure 24-2. Simplified CWG Block Diagram (Half-Bridge Mode, MODE<2:0> = 100)
Filename: 10-000209D.vsd
Title: SIMPLIFIED CWG BLOCK DIAGRAM (HALF-BRIDGE MODE)
Last Edit: 2/2/2016
First Used: PIC18(L)F6xK40
Notes:
Rev. 10-000209D
2/2/2016
1
0
1
0
1
0
1
0
00
11
10
01
00
11
10
01
00
11
10
01
00
11
10
01
LSAC<1:0>
LSBD<1:0>
LSAC<1:0>
LSBD<1:0>
CWG Clock clock
data in data out
clock
data in data out
CWG Data Input
E
DQ
REN
SHUTDOWN = 0
S
R
Q
POLA
POLB
POLC
POLD
CWG
Data
FREEZE D Q
CWG Data
CWGxD
CWGxC
CWGxB
CWGxA
1
1
0
1
1
0
0
0
High-Z
High-Z
High-Z
High-Z
Rising Dead-Band Block
Falling Dead-Band Block
CWG Data A
CWG Data B
EN
SHUTDOWN
CWG Data
Auto-shutdown source
(CWGxAS1 register)
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 403
24.2.2 Push-Pull Mode
In Push-Pull mode, two output signals are generated, alternating copies of the input as illustrated in
Figure 24-3. This alternation creates the push-pull effect required for driving some transformer-based
power supply designs. Steering modes are not used in Push-Pull mode. A basic block diagram for the
Push-Pull mode is shown in Figure 24-4.
The push-pull sequencer is reset whenever EN = 0 or if an auto-shutdown event occurs. The sequencer
is clocked by the first input pulse, and the first output appears on CWG1A.
The unused outputs CWGxC and CWGxD drive copies of CWGxA and CWGxB, respectively, but with
polarity controlled by the POLC and POLD bits of the CWGxCON1 register, respectively.
Figure 24-3. CWG Push-Pull Mode Operation
CWGx
clock
CWGxA
Input
source
CWGxB
Rev. 30-000098A
4/14/2017
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 404
Figure 24-4. Simplified CWG Block Diagram (Push-Pull Mode, MODE<2:0> = 101)
Filename: 10-000210D.vsd
Title: SIMPLIFIED CWG BLOCK DIAGRAM (PUSH-PULL MODE)
Last Edit: 2/2/2016
First Used: PIC18(L)F6xK40
Notes:
Rev. 10-000210D
2/2/2016
1
0
1
0
1
0
1
0
00
11
10
01
00
11
10
01
00
11
10
01
00
11
10
01
LSAC<1:0>
LSBD<1:0>
LSAC<1:0>
LSBD<1:0>
CWG Data
CWG Data Input
E
DQ
POLA
POLB
POLC
POLD
CWG
Data
FREEZE D Q
CWG Data
CWGxD
CWGxC
CWGxB
CWGxA
1
1
0
1
1
0
0
0
High-Z
High-Z
High-Z
High-Z
D Q
Q
CWG Data A
CWG Data B
EN
SHUTDOWN
REN
SHUTDOWN = 0
S
R
Q
Auto-shutdown source
(CWGxAS1 register)
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 405
24.2.3 Full-Bridge Modes
In Forward and Reverse Full-Bridge modes, three outputs drive static values while the fourth is
modulated by the input data signal. The mode selection may be toggled between forward and reverse by
toggling the MODE<0> bit of the CWGxCON0 while keeping MODE<2:1> static, without disabling the
CWG module. When connected, as shown in Figure 24-5, the outputs are appropriate for a full-bridge
motor driver. Each CWG output signal has independent polarity control, so the circuit can be adapted to
high-active and low-active drivers. A simplified block diagram for the Full-Bridge modes is shown in
Figure 24-6.
Figure 24-5. Example of Full-Bridge Application
Filename: 10-000263A.vsd
Title: Example of Full-Bridge Application
Last Edit: 12/8/2015
First Used: PIC18(L)F2x/4xK40
Note:
Rev. 10-000263A
12/8/2015
CWGxA
CWGxB
CWGxC
CWGxD
FET
Driver
FET
Driver
FET
Driver
FET
Driver
VDD
QA QC
QB QD
LOAD
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 406
Figure 24-6. Simplified CWG Block Diagram (Forward and Reverse Full-Bridge Modes)
Filename: 10-000212D.vsd
Title: SIMPLIFIED CWG BLOCK DIAGRAM (FULL-BRIDGE MODES)
Last Edit: 2/2/2016
First Used: PIC18(L)F6xK40
Notes:
Rev. 10-000212D
2/2/2016
1
0
1
0
1
0
1
0
00
11
10
01
00
11
10
01
00
11
10
01
00
11
10
01
LSAC<1:0>
LSBD<1:0>
LSAC<1:0>
LSBD<1:0>
CWG Clock clock
signal in
signal out
clock
signal insignal out
CWG Data Input
E
DQ
POLA
POLB
POLC
POLD
CWG Data
FREEZE D Q
CWG Data
CWGxD
CWGxC
CWGxB
CWGxA
1
1
0
1
1
0
0
0
High-Z
High-Z
High-Z
High-Z
Rising Dead-Band Block
Falling Dead-Band Block
CWG Data A
CWG Data B
EN
SHUTDOWN
MODE<2:0> = 010: Forward
MODE<2:0> = 011: Reverse
CWG Clock
MODE<2:0>
CWG
Data
cwg data
CWG Data C
CWG Data D
D Q
Q
CWG
Data
REN
SHUTDOWN = 0
S
R
Q
Auto-shutdown source
(CWGxAS1 register)
PIC18F26/45/46Q10
(CWG) Complementary Waveform Generator Modul...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 407
In Forward Full-Bridge mode (MODE = 010), CWGxA is driven to its Active state, CWGxB and CWGxC
are driven to their Inactive state, and CWGxD is modulated by the input signal, as shown in Figure 24-7.
In Reverse Full-Bridge mode (MODE = 011), CWGxC is driven to its Active state, CWGxA and CWGxD
are driven to their Inactive states, and CWGxB is modulated by the input signal, as shown in Figure 24-7.
In Full-Bridge mode, the dead-band period is used when there is a switch from forward to reverse or vice
versa. This dead-band control is described in 24.7 Dead-Band Control, with additional details in 24.8
Rising Edge and Reverse Dead Band and 24.9 Falling Edge and Forward Dead Band. Steering modes
are not used with either of the Full-Bridge modes. The mode selection may be toggled between forward
and reverse toggling the MODE<0> bit of the CWGxCON0 while keeping MODE<2:1> static, without
disabling the CWG module.
Figure 24-7. Example of Full-Bridge Output
CWGxA(2)
CWGxB(2)
CWGxC(2)
CWGxD(2)
Period
Pulse Width
(1) (1)
Forward
Mode
Pulse Width
Period
Reverse
Mode
CWGxA(2)
CWGxB(2)
CWGxC(2)
CWGxD(2)
(1) (1)
Rev. 30-000099A
4/14/2017
Note: 
1. A rising CWG data input creates a rising event on the modulated output.
2. Output signals shown as active-high; all POLy bits are clear.
24.2.3.1 Direction Change in Full-Bridge Mode
In Full-Bridge mode, changing MODE controls the forward/reverse direction. Direction changes occur on
the next rising edge of the modulated input.
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A direction change is initiated in software by changing the MODE bits. The sequence is illustrated in
Figure 24-8.
The associated active output CWGxA and the inactive output CWGxC are switched to drive in the
opposite direction.
The previously modulated output CWGxD is switched to the Inactive state, and the previously
inactive output CWGxB begins to modulate.
CWG modulation resumes after the direction-switch dead band has elapsed.
24.2.3.2 Dead-Band Delay in Full-Bridge Mode
Dead-band delay is important when either of the following conditions is true:
1. The direction of the CWG output changes when the duty cycle of the data input is at or near 100%,
or
2. The turn-off time of the power switch, including the power device and driver circuit, is greater than
the turn-on time.
The dead-band delay is inserted only when changing directions, and only the modulated output is
affected. The statically-configured outputs (CWGxA and CWGxC) are not afforded dead band, and switch
essentially simultaneously.
The following figure shows an example of the CWG outputs changing directions from forward to reverse,
at near 100% duty cycle. In this example, at time t1, the output of CWGxA and CWGxD become inactive,
while output CWGxC becomes active. Since the turn-off time of the power devices is longer than the turn-
on time, a shoot-through current will flow through power devices QC and QD for the duration of ‘t’. The
same phenomenon will occur to power devices QA and QB for the CWG direction change from reverse to
forward.
When changing the CWG direction at high duty cycle is required for an application, two possible solutions
for eliminating the shoot-through current are:
1. Reduce the CWG duty cycle for one period before changing directions.
2. Use switch drivers that can drive the switches off faster than they can drive them on.
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Figure 24-8. Example of PWM Direction Change at Near 100% Duty Cycle
Forward Period Reverse Period
t1
Pulse Width
Pulse Width
T
ON
TOFF
T = TOFF - TON
CWGxA
External Switch C
External Switch D
Potential Shoot-
Through Current
CWGxB
CWGxD
CWGxC
Rev. 30-000100A
4/14/2017
24.2.4 Steering Modes
In both Synchronous and Asynchronous Steering modes, the modulated input signal can be steered to
any combination of four CWG outputs. A fixed-value will be presented on all the outputs not used for the
PWM output. Each output has independent polarity, steering, and shutdown options. Dead-band control is
not used in either steering mode.
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Figure 24-9. Simplified CWG Block Diagram (Output Steering Modes)
Filename: 10-000211D.vsd
Title: SIMPLIFIED CWG BLO CK DIA GR AM (OU TP UT STEERING MODES)
Last Edit: 5/30/2017
First Used: PIC18(L)F6xK40
Notes:
Rev. 10-000211D
5/30/2017
1
0
1
0
1
0
1
0
00
11
10
01
00
11
10
01
00
11
10
01
00
11
10
01
LSAC<1:0>
LSBD<1:0>
LSAC<1:0>
LSBD<1:0>
CWG Data
Input
E
DQ
POLA
POLB
POLC
POLD
CWG
Data
FREEZE DQ
CWGxD
CWGxC
CWGxB
CWGxA
‘1’
‘1’
‘0’
‘1’
‘1’
‘0’
‘0’
‘0’
High-Z
High-Z
High-Z
High-Z
1
0
OVRD
STRD
1
0
OVRC
STRC
1
0
OVRB
STRB
1
0
OVRA
STRA
CWG Data
SHUTDOWN
CWG Data D
CWG Data C
CWG Data B
CWG Data A
EN
MODE<2:0> = 000: Asynchronous
MODE<2:0> = 001: Synchronous
REN
SHUTDOWN = 0
S
R
Q
Auto-shutdown source
(CWGxAS1 register)
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For example, when STRA = 0 then the corresponding pin is held at the level defined by OVRA. When
STRA = 1, then the pin is driven by the modulated input signal.
The POLy bits control the signal polarity only when STRy = 1.
The CWG auto-shutdown operation also applies in Steering modes as described in 24.11 Auto-
Shutdown”. An auto-shutdown event will only affect pins that have STRy = 1.
24.2.4.1 Synchronous Steering Mode
In Synchronous Steering mode (MODE=001), changes to steering selection registers take effect on the
next rising edge of the modulated data input (see figure below). In Synchronous Steering mode, the
output will always produce a complete waveform.
Important:  Only the STRx bits are synchronized; the OVRx bits are not synchronized.
Figure 24-10. Example of Synchronous Steering (MODE = 001)
CWGx
clock
CWGxA
Input
source
CWGxB
Rev. 30-000101A
4/14/2017
24.2.4.2 Asynchronous Steering Mode
In Asynchronous mode (MODE = 000), steering takes effect at the end of the instruction cycle that writes
to STRx. In Asynchronous Steering mode, the output signal may be an incomplete waveform (see figure
below). This operation may be useful when the user firmware needs to immediately remove a signal from
the output pin.
Figure 24-11. Example of Asynchronous Steering (MODE = 000)
CWGx
INPUT
STRA
End of Instruction Cycle End of Instruction Cycle
CWGxA
CWGxA Follows CWGx data input
Rev. 30-000102A
4/14/2017
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24.3 Start-up Considerations
The application hardware must use the proper external pull-up and/or pull-down resistors on the CWG
output pins. This is required because all I/O pins are forced to high-impedance at Reset.
The polarity control bits (POLy) allow the user to choose whether the output signals are active-high or
active-low.
24.4 Clock Source
The clock source is used to drive the dead-band timing circuits. The CWG module allows the following
clock sources to be selected:
FOSC (system clock)
HFINTOSC
When the HFINTOSC is selected, the HFINTOSC will be kept running during Sleep. Therefore, CWG
modes requiring dead band can operate in Sleep, provided that the CWG data input is also active during
Sleep. The clock sources are selected using the CS bit. The system clock FOSC, is disabled in Sleep and
thus dead-band control cannot be used.
24.5 Selectable Input Sources
The CWG generates the output waveforms from the input sources which are selected with the ISM bits as
shown below.
Table 24-1. CWG Data Input Sources
ISM Data Source
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0111 DSM_out
0110 CMP2_out
0101 CMP1_out
0100 PWM4_out
0011 PWM3_out
0010 CCP2_out
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...........continued
ISM Data Source
0001 CCP1_out
0000 Pin selected by CWGxPPS
24.6 Output Control
24.6.1 CWG Outputs
Each CWG output can be routed to a Peripheral Pin Select (PPS) output via the RxyPPS register.
Related Links
17. (PPS) Peripheral Pin Select Module
24.6.2 Polarity Control
The polarity of each CWG output can be selected independently. When the output polarity bit is set, the
corresponding output is active-high. Clearing the output polarity bit configures the corresponding output
as active-low. However, polarity does not affect the override levels. Output polarity is selected with the
POLy bits. Auto-shutdown and steering options are unaffected by polarity.
24.7 Dead-Band Control
The dead-band control provides non-overlapping PWM signals to prevent shoot-through current in PWM
switches. Dead-band operation is employed for Half-Bridge and Full-Bridge modes. The CWG contains
two 6-bit dead-band counters. One is used for the rising edge of the input source control in Half-Bridge
mode or for reverse dead-band Full-Bridge mode. The other is used for the falling edge of the input
source control in Half-Bridge mode or for forward dead band in Full-Bridge mode.
Dead band is timed by counting CWG clock periods from zero up to the value in the rising or falling dead-
band counter registers.
24.7.1 Dead-Band Functionality in Half-Bridge mode
In Half-Bridge mode, the dead-band counters dictate the delay between the falling edge of the normal
output and the rising edge of the inverted output. This can be seen in Figure 24-1.
24.7.2 Dead-Band Functionality in Full-Bridge mode
In Full-Bridge mode, the dead-band counters are used when undergoing a direction change. The
MODE<0> bit can be set or cleared while the CWG is running, allowing for changes from Forward to
Reverse mode. The CWGxA and CWGxC signals will change immediately upon the first rising input edge
following a direction change, but the modulated signals (CWGxB or CWGxD, depending on the direction
of the change) will experience a delay dictated by the dead-band counters.
24.8 Rising Edge and Reverse Dead Band
In Half-Bridge mode, the rising edge dead band delays the turn-on of the CWGxA output after the rising
edge of the CWG data input. In Full-Bridge mode, the reverse dead-band delay is only inserted when
changing directions from Forward mode to Reverse mode, and only the modulated output CWGxB is
affected.
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The 24.15.8 CWGxDBR register determines the duration of the dead-band interval on the rising edge of
the input source signal. This duration is from 0 to 64 periods of the CWG clock.
Dead band is always initiated on the edge of the input source signal. A count of zero indicates that no
dead band is present.
If the input source signal reverses polarity before the dead-band count is completed, then no signal will
be seen on the respective output.
The CWGxDBR register value is double-buffered. When EN = 0, the buffer is loaded when CWGxDBR is
written. When EN = 1, then the buffer will be loaded at the rising edge following the first falling edge of the
data input, after the LD bit is set. Refer to the following figure for an example.
Figure 24-12. Dead-Band Operation, CWGxDBR = 0x01, CWGxDBF = 0x02
Input Source
CWGxA
CWGxB
cwg_clock
Rev. 30-000103A
4/14/2017
24.9 Falling Edge and Forward Dead Band
In Half-Bridge mode, the falling edge dead band delays the turn-on of the CWGxB output at the falling
edge of the CWG data input. In Full-Bridge mode, the forward dead-band delay is only inserted when
changing directions from Reverse mode to Forward mode, and only the modulated output CWGxD is
affected.
The 24.15.9 CWGxDBF register determines the duration of the dead-band interval on the falling edge of
the input source signal. This duration is from zero to 64 periods of CWG clock.
Dead-band delay is always initiated on the edge of the input source signal. A count of zero indicates that
no dead band is present.
If the input source signal reverses polarity before the dead-band count is completed, then no signal will
be seen on the respective output.
The CWGxDBF register value is double-buffered. When EN = 0, the buffer is loaded when CWGxDBF is
written. When EN = 1, then the buffer will be loaded at the rising edge following the first falling edge of the
data input after the LD is set. Refer to the following figure for an example.
Figure 24-13. Dead-Band Operation, CWGxDBR = 0x03, CWGxDBF = 0x06, Source Shorter Than
Dead Band
source shorter than dead band
Input Source
CWGxA
CWGxB
cwg_clock
Rev. 30-000104A
4/14/2017
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24.10 Dead-Band Jitter
When the rising and falling edges of the input source are asynchronous to the CWG clock, it creates jitter
in the dead-band time delay. The maximum jitter is equal to one CWG clock period. Refer to the
equations below for more details.
Figure 24-14. Dead-Band Delay Time Calculation
 _ =1
_
 < 5:0 > _ =1
_
 < 5: 0 > + 1
 = _  _ =1
_
 _ = _ +
Figure 24-15. Dead-Band Delay Example Calculation
 < 5:0 > = 00= 10
_ = 8 
 =1
8 = 125
 _ = 125 10 = 125
 _ = 1.25 + 0.125  = 1.37
24.11 Auto-Shutdown
Auto-shutdown is a method to immediately override the CWG output levels with specific overrides that
allow for safe shutdown of the circuit. The shutdown state can be either cleared automatically or held until
cleared by software. The auto-shutdown circuit is illustrated in the following figure.
Figure 24-16. CWG Shutdown Block Diagram
Filename: 10-000172C.vsd
Title: CWG SHUTDOWN BLOCK DIAGRAM
Last Edit: 8/7/2015
First Used: PIC16(L)F1614/5/8/9 LECW
Notes:
Rev. 10-000172C
8/7/2015
S
R
Q
Write 1 to
SHUTDOWN bit
AS0E
C1OUT_sync
C2OUT_sync
TMR2_postscaled
TMR4_postscaled
TMR6_postscaled
REN
Write 0 to
SHUTDOWN bit
SHUTDOWN
FREEZE D
CK
Q
S
CWG_data
CWG_shutdown
PPS
CWGxINPPS
AS4E
AS5E
AS1E
AS2E
AS3E
24.11.1 Shutdown
The shutdown state can be entered by either of the following two methods:
Software Generated
External Input
24.11.1.1 Software Generated Shutdown
Setting the SHUTDOWN bit will force the CWG into the shutdown state.
When the auto-restart is disabled, the shutdown state will persist as long as the SHUTDOWN bit is set.
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When auto-restart is enabled, the SHUTDOWN bit will clear automatically and resume operation on the
next rising edge event. The SHUTDOWN bit indicates when a shutdown condition exists. The bit may be
set or cleared in software or by hardware.
24.11.1.2 External Input Source
External shutdown inputs provide the fastest way to safely suspend CWG operation in the event of a
Fault condition. When any of the selected shutdown inputs goes active, the CWG outputs will immediately
go to the selected override levels without software delay. The override levels are selected by the LSBD
and LSAC bits. Several input sources can be selected to cause a shutdown condition. All input sources
are active-low. The shutdown input sources are individually enabled by the ASyE bits as shown in the
following table:
Table 24-2. Shutdown Sources
ASyE Source
AS7E CLC6_out (low causes shutdown)
AS6E CLC2_out (low causes shutdown)
AS5E CMP2_out (low causes shutdown)
AS4E CMP1_out (low causes shutdown)
AS3E TMR6_postscaled (high causes shutdown)
AS2E TMR4_postscaled (high causes shutdown)
AS1E TMR2_postscaled (high causes shutdown)
AS0E Pin selected by CWGxPPS (low causes shutdown)
Important:  Shutdown inputs are level sensitive, not edge sensitive. The shutdown state
cannot be cleared, except by disabling auto-shutdown, as long as the shutdown input level
persists.
24.11.1.3 Pin Override Levels
The levels driven to the CWG outputs during an auto-shutdown event are controlled by the LSBD and
LSAC bits. The LSBD bits control CWGxB/D output levels, while the LSAC bits control the CWGxA/C
output levels.
24.11.1.4 Auto-Shutdown Interrupts
When an auto-shutdown event occurs, either by software or hardware setting SHUTDOWN, the CWGxIF
flag bit of the PIRx register is set.
Related Links
14.13.9 PIR7
24.11.2 Auto-Shutdown Restart
After an auto-shutdown event has occurred, there are two ways to resume operation:
Software controlled
Auto-restart
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In either case, the shutdown source must be cleared before the restart can take place. That is, either the
shutdown condition must be removed, or the corresponding ASyE bit must be cleared.
24.11.2.1 Software-Controlled Restart
When the REN bit is clear (REN = 0), the CWG module must be restarted after an auto-shutdown event
through software.
Once all auto-shutdown sources are removed, the software must clear SHUTDOWN. Once SHUTDOWN
is cleared, the CWG module will resume operation upon the first rising edge of the CWG data input.
Important:  The SHUTDOWN bit cannot be cleared in software if the auto-shutdown condition
is still present.
Figure 24-17. SHUTDOWN FUNCTIONALITY, AUTO-RESTART DISABLED (REN = 0, LSAC = 01,
LSBD = 01)
Shutdown
REN Cleared by Software
Output Resumes
No Shutdown
CWG Input
SHUTDOWN
Source
Shutdown Source
Shutdown Event Ceases
Tri-State (No Pulse)
Tri-State (No Pulse)
CWGxC
Rev. 30-000105A
4/14/2017
CWGxD
CWGxA
CWGxB
24.11.2.2 Auto-Restart
When the REN bit is set (REN = 1), the CWG module will restart from the shutdown state automatically.
Once all auto-shutdown conditions are removed, the hardware will automatically clear SHUTDOWN.
Once SHUTDOWN is cleared, the CWG module will resume operation upon the first rising edge of the
CWG data input.
Important:  The SHUTDOWN bit cannot be cleared in software if the auto-shutdown condition
is still present.
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Figure 24-18. SHUTDOWN FUNCTIONALITY, AUTO-RESTART ENABLED (REN = 1, LSAC = 01,
LSBD = 01)
Shutdown
Tri-State (No Pulse)
REN auto-cleared by hardware
Output Resumes
No Shutdown
CWG Input
SHUTDOWN
Source
Shutdown Source
Shutdown Event Ceases
Tri-State (No Pulse)
Rev. 30-000106A
4/14/2017
CWGxA
CWGxB
CWGxC
CWGxD
24.12 Operation During Sleep
The CWG module operates independently from the system clock and will continue to run during Sleep,
provided that the clock and input sources selected remain active.
The HFINTOSC remains active during Sleep when all the following conditions are met:
CWG module is enabled
Input source is active
HFINTOSC is selected as the clock source, regardless of the system clock source selected.
In other words, if the HFINTOSC is simultaneously selected as the system clock and the CWG clock
source, when the CWG is enabled and the input source is active, then the CPU will go idle during Sleep,
but the HFINTOSC will remain active and the CWG will continue to operate. This will have a direct effect
on the Sleep mode current.
24.13 Configuring the CWG
1. Ensure that the TRIS control bits corresponding to CWG outputs are set so that all are configured
as inputs, ensuring that the outputs are inactive during setup. External hardware should ensure that
pin levels are held to safe levels.
2. Clear the EN bit, if not already cleared.
3. Configure the MODE bits to set the output operating mode.
4. Configure the POLy bits to set the output polarities.
5. Configure the ISM bits to select the data input source.
6. If a steering mode is selected, configure the STRy bits to select the desired output on the CWG
outputs.
7. Configure the LSBD and LSAC bits to select the auto-shutdown output override states (this is
necessary even if not using auto-shutdown because start-up will be from a shutdown state).
8. If auto-restart is desired, set the REN bit.
9. If auto-shutdown is desired, configure the ASyE bits to select the shutdown source.
10. Set the desired rising and falling dead-band times with the CWGxDBR and CWGxDBF registers.
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11. Select the clock source with the CS bits.
12. Set the EN bit to enable the module.
13. Clear the TRIS bits that correspond to the CWG outputs to set them as outputs.
If auto-restart is to be used, set the REN bit and the SHUTDOWN bit will be cleared automatically.
Otherwise, clear the SHUTDOWN bit in software to start the CWG.
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24.14 Register Summary - CWG Control
Address Name Bit Pos.
0x0F3B CWG1CLK 7:0 CS
0x0F3C CWG1ISM 7:0 ISM[3:0]
0x0F3D CWG1DBR 7:0 DBR[5:0]
0x0F3E CWG1DBF 7:0 DBF[5:0]
0x0F3F CWG1CON0 7:0 EN LD MODE[2:0]
0x0F40 CWG1CON1 7:0 IN POLD POLC POLB POLA
0x0F41 CWG1AS0 7:0 SHUTDOWN REN LSBD[1:0] LSAC[1:0]
0x0F42 CWG1AS1 7:0 AS7E AS6E AS5E AS4E AS3E AS2E AS1E AS0E
0x0F43 CWG1STR 7:0 OVRD OVRC OVRB OVRA STRD STRC STRB STRA
24.15 Register Definitions: CWG Control
Long bit name prefixes for the CWG peripherals are shown in the table below. Refer to the "Long Bit
Names Section" for more information.
Table 24-3. CWG Bit Name Prefixes
Peripheral Bit Name Prefix
CWG1 CWG1
Related Links
1.4.2.2 Long Bit Names
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24.15.1 CWGxCON0
Name:  CWGxCON0
Address:  0x0F3F
CWG Control Register 0
Bit 7 6 5 4 3 2 1 0
EN LD MODE[2:0]
Access R/W R/W/HC R/W R/W R/W
Reset 0 0 0 0 0
Bit 7 – EN CWG1 Enable bit
Value Description
1Module is enabled
0Module is disabled
Bit 6 – LD  CWG1 Load Buffers bit(1)
Value Description
1Dead-band count buffers to be loaded on CWG data rising edge, following first falling edge
after this bit is set
0Buffers remain unchanged
Bits 2:0 – MODE[2:0] CWG1 Mode bits
Value Description
111 Reserved
110 Reserved
101 CWG outputs operate in Push-Pull mode
100 CWG outputs operate in Half-Bridge mode
011 CWG outputs operate in Reverse Full-Bridge mode
010 CWG outputs operate in Forward Full-Bridge mode
001 CWG outputs operate in Synchronous Steering mode
000 CWG outputs operate in Asynchronous Steering mode
Note: 
1. This bit can only be set after EN = 1; it cannot be set in the same cycle when EN is set.
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24.15.2 CWGxCON1
Name:  CWGxCON1
Address:  0x0F40
CWG Control Register 1
Bit 7 6 5 4 3 2 1 0
IN POLD POLC POLB POLA
Access RO R/W R/W R/W R/W
Reset x 0 0 0 0
Bit 5 – IN CWG Input Value bit (read-only)
Value Description
1CWG input is a logic 1
0CWG input is a logic 0
Bits 0, 1, 2, 3 – POLy CWG Output 'y' Polarity bit
Value Description
1Signal output is inverted polarity
0Signal output is normal polarity
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24.15.3 CWGxCLK
Name:  CWGxCLK
Address:  0x0F3B
CWGx Clock Input Selection Register
Bit 7 6 5 4 3 2 1 0
CS
Access R/W
Reset 0
Bit 0 – CS Clock Source
CWG Clock Source Selection Select bits
Value Description
1HFINTOSC (remains operating during Sleep)
0FOSC
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24.15.4 CWGxISM
Name:  CWGxISM
Address:  0x0F3C
CWGx Input Selection Register
Bit 7 6 5 4 3 2 1 0
ISM[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – ISM[3:0] CWG Data Input Source Select bits
Table 24-4. CWG Data Input Sources
ISM Data Source
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0111 DSM_out
0110 CMP2_out
0101 CMP1_out
0100 PWM4_out
0011 PWM3_out
0010 CCP2_out
0001 CCP1_out
0000 Pin selected by CWGxPPS
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24.15.5 CWGxSTR
Name:  CWGxSTR
Address:  0x0F43
CWG Steering Control Register (1)
Bit 7 6 5 4 3 2 1 0
OVRD OVRC OVRB OVRA STRD STRC STRB STRA
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 4, 5, 6, 7 – OVRy Steering Data OVR'y' bit
Value Condition Description
xSTRy = 1CWGx'y' output has the CWG data input waveform with polarity
control from POLy bit
1STRy = 0 and POLy = xCWGx'y' output is high
0STRy = 0 and POLy = xCWGx'y' output is low
Bits 0, 1, 2, 3 – STRy  STR'y' Steering Enable bit(2)
Value Description
1CWGx'y' output has the CWG data input waveform with polarity control from POLy bit
0CWGx'y' output is assigned to value of OVRy bit
Note: 
1. The bits in this register apply only when MODE = '00x' (24.15.1 CWGxCON0, Steering modes).
2. This bit is double-buffered when MODE = '001'.
PIC18F26/45/46Q10
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 426
24.15.6 CWGxAS0
Name:  CWGxAS0
Address:  0x0F41
CWG Auto-Shutdown Control Register 0
Bit 7 6 5 4 3 2 1 0
SHUTDOWN REN LSBD[1:0] LSAC[1:0]
Access R/W/HS/HC R/W R/W R/W R/W R/W
Reset 0 0 0 1 0 1
Bit 7 – SHUTDOWN  Auto-Shutdown Event Status bit(1,2)
Value Description
1An auto-shutdown state is in effect
0No auto-shutdown event has occurred
Bit 6 – REN Auto-Restart Enable bit
Value Description
1Auto-restart is enabled
0Auto-restart is disabled
Bits 5:4 – LSBD[1:0] CWGxB and CWGxD Auto-Shutdown State Control bits
Value Description
11 A logic ‘1’ is placed on CWGxB/D when an auto-shutdown event occurs.
10 A logic ‘0’ is placed on CWGxB/D when an auto-shutdown event occurs.
01 Pin is tri-stated on CWGxB/D when an auto-shutdown event occurs.
00 The Inactive state of the pin, including polarity, is placed on CWGxB/D after the required
dead-band interval when an auto-shutdown event occurs.
Bits 3:2 – LSAC[1:0] CWGxA and CWGxC Auto-Shutdown State Control bits
Value Description
11 A logic ‘1’ is placed on CWGxA/C when an auto-shutdown event occurs.
10 A logic ‘0’ is placed on CWGxA/C when an auto-shutdown event occurs.
01 Pin is tri-stated on CWGxA/C when an auto-shutdown event occurs.
00 The Inactive state of the pin, including polarity, is placed on CWGxA/C after the required
dead-band interval when an auto-shutdown event occurs.
Note: 
1. This bit may be written while EN = 0 (24.15.1 CWGxCON0), to place the outputs into the shutdown
configuration.
2. The outputs will remain in auto-shutdown state until the next rising edge of the CWG data input
after this bit is cleared.
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24.15.7 CWGxAS1
Name:  CWGxAS1
Address:  0x0F42
CWG Auto-Shutdown Control Register 1
Bit 7 6 5 4 3 2 1 0
AS7E AS6E AS5E AS4E AS3E AS2E AS1E AS0E
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – ASyE CWG Auto-shutdown Source ASyE Enable bit(1)
Table 24-5. Shutdown Sources
ASyE Source
AS7E CLC6_out (low causes shutdown)
AS6E CLC2_out (low causes shutdown)
AS5E CMP2_out (low causes shutdown)
AS4E CMP1_out (low causes shutdown)
AS3E TMR6_postscaled (high causes shutdown)
AS2E TMR4_postscaled (high causes shutdown)
AS1E TMR2_postscaled (high causes shutdown)
AS0E Pin selected by CWGxPPS (low causes shutdown)
Value Description
1Auto-shutdown for source ASyE is enabled
0Auto-shutdown for source ASyE is disabled
Note:  This bit may be written while EN = 0 (24.15.1 CWGxCON0), to place the outputs into the
shutdown configuration.
The outputs will remain in auto-shutdown state until the next rising edge of the CWG data input after this
bit is cleared.
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24.15.8 CWGxDBR
Name:  CWGxDBR
Address:  0x0F3D
CWG Rising Dead-Band Count Register
Bit 7 6 5 4 3 2 1 0
DBR[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset x x x x x x
Bits 5:0 – DBR[5:0] CWG Rising Edge-Triggered Dead-Band Count bits
Reset States: POR/BOR = xxxxxx
All Other Resets = uuuuuu
Value Description
nDead band is active no less than n, and no more than n+1, CWG clock periods after the
rising edge
00 CWG clock periods. Dead-band generation is bypassed
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24.15.9 CWGxDBF
Name:  CWGxDBF
Address:  0x0F3E
CWG Falling Dead-Band Count Register
Bit 7 6 5 4 3 2 1 0
DBF[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset x x x x x x
Bits 5:0 – DBF[5:0] CWG Falling Edge-Triggered Dead-Band Count bits
Reset States: POR/BOR = xxxxxx
All Other Resets = uuuuuu
Value Description
nDead band is active no less than n, and no more than n+1, CWG clock periods after the
falling edge
00 CWG clock periods. Dead-band generation is bypassed
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25. (CLC) Configurable Logic Cell
The Configurable Logic Cell (CLCx) module provides programmable logic that operates outside the
speed limitations of software execution. The logic cell takes up to 64input signals and, through the use of
configurable gates, reduces the 64inputs to four logic lines that drive one of eight selectable single-output
logic functions.
Input sources are a combination of the following:
I/O pins
Internal clocks
Peripherals
Register bits
The output can be directed internally to peripherals and to an output pin.
Important:  There are several CLC instances on this device. Throughout this section, the lower
case ‘x’ in register names is a generic reference to the CLC instance number. For example, the
first instance of the control register is CLC1CON and is generically described in this chapter as
CLCxCON.
The following figure is a simplified diagram showing signal flow through the CLC. Possible configurations
include:
Combinatorial Logic:
AND
NAND
AND-OR
AND-OR-INVERT
OR-XOR
OR-XNOR
Latches:
S-R
Clocked D with Set and Reset
Transparent D with Set and Reset
Clocked J-K with Reset
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 431
Figure 25-1. CLC Simplified Block Diagram
Input Data Selection Gates(1)
Logic
Function
(2)
lcxg2
lcxg1
lcxg3
lcxg4
MODE<2:0>
lcxq
EN
POL
det
Interrupt
det
Interrupt
set bit
CLCxIF
INTN
INTP
CLCx
to Peripherals
Q1
CLCx_out
OUT
CLCxOUT
D Q
PPS
LCx_in[0]
LCx_in[1]
LCx_in[2]
LCx_in[n-2]
LCx_in[n-1]
LCx_in[n]
.
.
.
Rev. 10-000025H
11/9/2016
CLCxPPS
TRIS
Note: 
1. See Figure 25-2 for input data selection and gating.
2. See Figure 25-3 for programmable logic functions.
25.1 CLC Setup
Programming the CLC module is performed by configuring the four stages in the logic signal flow. The
four stages are:
Data selection
Data gating
Logic function selection
Output polarity
Each stage is setup at run time by writing to the corresponding CLC Special Function Registers. This has
the added advantage of permitting logic reconfiguration on-the-fly during program execution.
25.1.1 Data Selection
There are 64signals available as inputs to the configurable logic. Four 64-input multiplexers are used to
select the inputs to pass on to the next stage.
Data selection is through four multiplexers as indicated on the left side of the following diagram. Data
inputs in the figure are identified by a generic numbered input name.
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 432
Figure 25-2. Input Data Selection and Gating
lcxg1
G1POL
Data GATE 1
G 1 D1 T
lcxg2
lcxg3
lcxg4
Data GATE 2
Data GATE 3
Data GATE 4
G 1 D1 N
G 1 D2 T
G 1 D2 N
G 1 D3 T
G 1 D3 N
G 1 D4 T
G 1 D4 N
D1S<5:0>
D2S<5:0>
D3S<5:0>
D4S<5:0>
LCx_in[0]
LCx_in[n]
000000
111111
Data Selection
Note: All controls are undefined at power-up.
d1T
d1N
d2T
d2N
d3T
d3N
d4T
d4N
(Same as Data GATE 1)
(Same as Data GATE 1)
(Same as Data GATE 1)
LCx_in[0]
LCx_in[n]
000000
111111
LCx_in[0]
LCx_in[n]
000000
111111
LCx_in[0]
LCx_in[n]
000000
111111
Rev. 30-000149A
6/12/2017
The following table correlates the generic input name to the actual signal for each CLC module. The
column labeled ‘DyS Value’ indicates the MUX selection code for the selected data input. DyS is an
abbreviation for the MUX select input codes: D1S through D4S where 'y' is the gate number.
PIC18F26/45/46Q10
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CLC Data Input Sources
DyS Value CLC Input Source DyS Value CLC Input Source
111111 [63] Reserved 011111 [31] IOC_flag
111110 [62] Reserved 011110 [30] ZCD_out
111101 [61] Reserved 011101 [29] CMP2_out
111100 [60] Reserved 011100 [28] CMP1_out
111011 [59] Reserved 011011 [27] PWM4_out
111010 58] Reserved 011010 [26] PWM3_out
111001 [57] Reserved 011001 [25] CCP2_out
111000 [56] Reserved 011000 [24] CCP1 _out
110111 [55] Reserved 010111 [23] TMR6_out
110110 [54] Reserved 010110 [22] TMR5 _overflow
110101 [53] Reserved 010101 [21] TMR4 _out
110100 [52] Reserved 010100 [20] TMR3 _overflow
110011 [51] Reserved 010011 [19] TMR2 _out
110010 [50] CWG1B_out 010010 [18] TMR1 _overflow
110001 [49] CWG1A_out 010001 [17] TMR0 _overflow
110000 [48] SCK2 010000 [16] CLKR _out
101111 [47] SDO2 001111 [15] ADCRC
101110 [46] SCK1 001110 [14] SOSC
101101 [45] SDO1 001101 [13] SFINTOSC (1MHz)
101100 [44] EUSART2_TX/CK_out 001100 [12] MFINTOSC (32 kHz)
101011 [43] EUSART2_DT_out 001011 [11] MFINTOSC (500 kHz)
101010 [42] EUSART1_TX/CK_out 001010 [10] LFINTOSC
101001 [41] EUSART1_DT_out 001001 [9] HFINTOSC
101000 [40] CLC8_out 001000 [8] FOSC
100111 [39] CLC7_out 000111 [7] CLCIN7PPS
100110 [38] CLC6_out 000110 [6] CLCIN6PPS
100101 [37] CLC5_out 000101 [5] CLCIN5PPS
100100 [36] CLC4_out 000100 [4] CLCIN4PPS
100011 [35] CLC3_out 000011 [3] CLCIN3PPS
100010 [34] CLC2_out 000010 [2] CLCIN2PPS
100001 [33] CLC1_out 000001 [1] CLCIN1PPS
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...........continued
DyS Value CLC Input Source DyS Value CLC Input Source
100000 [32] DSM1_out 000000 [0] CLCIN0PPS
Data inputs are selected with CLCxSEL0 through CLCxSEL3 registers.
Important:  Data selections are undefined at power-up.
25.1.2 Data Gating
Outputs from the input multiplexers are directed to the desired logic function input through the data gating
stage. Each data gate can direct any combination of the four selected inputs.
The gate stage is more than just signal direction. The gate can be configured to direct each input signal
as inverted or non-inverted data. Directed signals are ANDed together in each gate. The output of each
gate can be inverted before going on to the logic function stage.
The gating is in essence a 1-to-4 input AND/NAND/OR/NOR gate. When every input is inverted and the
output is inverted, the gate is an AND of all enabled data inputs. When the inputs and output are not
inverted, the gate is an OR or all enabled inputs.
The following table summarizes the basic logic that can be obtained in gate 1 by using the gate logic
select bits. The table shows the logic of four input variables, but each gate can be configured to use less
than four. If no inputs are selected, the output will be zero or one, depending on the gate output polarity
bit.
Table 25-1. Data Gating Logic
CLCxGLSy GyPOL Gate Logic
0x55 1AND
0x55 0NAND
0xAA 1NOR
0xAA 0OR
0x00 0Logic 0
0x00 1Logic 1
It is possible (but not recommended) to select both the true and negated values of an input. When this is
done, the gate output is zero, regardless of the other inputs, but may emit logic glitches (transient-
induced pulses). If the output of the channel must be zero or one, the recommended method is to set all
gate bits to zero and use the gate polarity bit to set the desired level.
Data gating is configured with the logic gate select registers as follows:
Gate 1: CLCxGLS0
Gate 2: CLCxGLS1
Gate 3: CLCxGLS2
Gate 4: CLCxGLS3
PIC18F26/45/46Q10
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Register number suffixes are different than the gate numbers because other variations of this module
have multiple gate selections in the same register.
Data gating is indicated in the right side of Figure 25-2. Only one gate is shown in detail. The remaining
three gates are configured identically with the exception that the data enables correspond to the enables
for that gate.
25.1.3 Logic Function
There are eight available logic functions including:
AND-OR
OR-XOR
AND
S-R Latch
D Flip-Flop with Set and Reset
D Flip-Flop with Reset
J-K Flip-Flop with Reset
Transparent Latch with Set and Reset
Logic functions are shown in the following diagram. Each logic function has four inputs and one output.
The four inputs are the four data gate outputs of the previous stage. The output is fed to the inversion
stage and from there to other peripherals, an output pin, and back to the CLC itself.
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 436
Figure 25-3. Programmable Logic Functions
lcxg
1
lcxg
2
lcxg
3
lcxg
4
lcxq
AND
-
OR
OR
-
XOR
MODE
<
2
:
0
>
=
000
MODE
<
2
:
0
>
=
001
4
-
input AND
S
-
R Latch
MODE
<
2
:
0
>
=
010
MODE
<
2
:
0
>
=
011
lcxg
1
lcxg
2
lcxg
3
lcxg
4
lcxq
S
R
Q
lcxq
lcxg
1
lcxg
2
lcxg
3
lcxg
4
lcxg
1
lcxg
2
lcxg
3
lcxg
4
lcxq
1
-
Input D Flip
-
Flop with S and R
2
-
Input D Flip
-
Flop with R
J
-
K Flip
-
Flop with R
1
-
Input Transparent Latch with S and R
MODE
<
2
:
0
>
=
100
MODE
<
2
:
0
>
=
101
MODE
<
2
:
0
>
=
110
MODE
<
2
:
0
>
=
111
D
R
Q
lcxq
lcxg
1
lcxg
2
lcxg
3
lcxg
4
D
R
Q
S
lcxg
1
lcxg
2
lcxg
3
lcxg
4
lcxq
J
R
Q
K
lcxg
1
lcxg
2
lcxg
3
lcxg
4
lcxq
D
R
Q
S
LE
lcxq
lcxg
1
lcxg
2
lcxg
3
lcxg
4
Rev. 10-000122B
9/13/2016
25.1.4 Output Polarity
The last stage in the CLC is the output polarity. Setting the POL bit inverts the output signal from the logic
stage. Changing the polarity while the interrupts are enabled will cause an interrupt for the resulting
output transition.
25.2 CLC Interrupts
An interrupt will be generated upon a change in the output value of the CLCx when the appropriate
interrupt enables are set. A rising edge detector and a falling edge detector are present in each CLC for
this purpose.
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
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The CLCxIF bit of the associated PIR register will be set when either edge detector is triggered and its
associated enable bit is set. The INTP enables rising edge interrupts and the INTN bit enables falling
edge interrupts.
To fully enable the interrupt, set the following bits:
CLCxIE bit of the respective PIE register
INTP bit (for a rising edge detection)
INTN bit (for a falling edge detection)
If priority interrupts are not used
Clear the IPEN bit of the INTCON register
Set the GIE bit of the INTCON register
Set the PEIE bit of the INTCON register
If the CLC is a high-priority interrupt
Set the IPEN bit of the INTCON register
Set the CLCxIP bit of the respective IPR register
Set the GIEH bit of the INTCON register
If the CLC is a low-priority interrupt
Set the IPEN bit of the INTCON register
Clear the CLCxIP bit of the respective IPR register
Set the GIEL bit of the INTCON register
The CLCxIF bit of the respective PIR register, must be cleared in software as part of the interrupt service.
If another edge is detected while this flag is being cleared, the flag will still be set at the end of the
sequence.
25.3 Output Mirror Copies
Mirror copies of all CLCxOUT bits are contained in the 25.8.11 CLCDATA register. Reading this register
reads the outputs of all CLCs simultaneously. This prevents any reading skew introduced by testing or
reading the OUT bits in the individual CLCxCON registers.
25.4 Effects of a Reset
The CLCxCON register is cleared to zero as the result of a Reset. All other selection and gating values
remain unchanged.
25.5 Operation During Sleep
The CLC module operates independently from the system clock and will continue to run during Sleep,
provided that the input sources selected remain active.
The HFINTOSC remains active during Sleep when the CLC module is enabled and the HFINTOSC is
selected as an input source, regardless of the system clock source selected.
In other words, if the HFINTOSC is simultaneously selected as the system clock and as a CLC input
source, when the CLC is enabled, the CPU will go idle during Sleep, but the CLC will continue to operate
and the HFINTOSC will remain active.
This will have a direct effect on the Sleep mode current.
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 438
25.6 CLC Setup Steps
The following steps should be followed when setting up the CLC:
Disable CLC by clearing the EN bit.
Select desired inputs using the CLCxSEL0 through CLCxSEL3 registers (See CLC Data Input Table).
Clear any associated ANSEL bits.
Set all TRIS bits associated with inputs.
Enable the chosen inputs through the four gates using the CLCxGLS0 through CLCxGLS3 registers.
Select the gate output polarities with the GyPOL bits
Select the desired logic function with the MODE bits
Select the desired polarity of the logic output with the POL bit. (This step may be combined with the
previous gate output polarity step).
If driving a device pin, set the desired pin PPS control register and also clear the TRIS bit
corresponding to that output.
Configure the interrupts (optional). See 25.2 CLC Interrupts
Enable the CLC by setting the EN bit.
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 439
25.7 Register Summary - CLC Control
Address Name Bit Pos.
0x0E27 CLC1CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E28 CLC1POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E29 CLC1SEL0 7:0 D1S[5:0]
0x0E2A CLC1SEL1 7:0 D2S[5:0]
0x0E2B CLC1SEL2 7:0 D3S[5:0]
0x0E2C CLC1SEL3 7:0 D4S[5:0]
0x0E2D CLC1GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E2E CLC1GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E2F CLC1GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E30 CLC1GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E31 CLC2CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E32 CLC2POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E33 CLC2SEL0 7:0 D1S[5:0]
0x0E34 CLC2SEL1 7:0 D2S[5:0]
0x0E35 CLC2SEL2 7:0 D3S[5:0]
0x0E36 CLC2SEL3 7:0 D4S[5:0]
0x0E37 CLC2GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E38 CLC2GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E39 CLC2GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E3A CLC2GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E3B CLC3CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E3C CLC3POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E3D CLC3SEL0 7:0 D1S[5:0]
0x0E3E CLC3SEL1 7:0 D2S[5:0]
0x0E3F CLC3SEL2 7:0 D3S[5:0]
0x0E40 CLC3SEL3 7:0 D4S[5:0]
0x0E41 CLC3GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E42 CLC3GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E43 CLC3GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E44 CLC3GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E45 CLC4CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E46 CLC4POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E47 CLC4SEL0 7:0 D1S[5:0]
0x0E48 CLC4SEL1 7:0 D2S[5:0]
0x0E49 CLC4SEL2 7:0 D3S[5:0]
0x0E4A CLC4SEL3 7:0 D4S[5:0]
0x0E4B CLC4GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E4C CLC4GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E4D CLC4GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E4E CLC4GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E4F CLC5CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E50 CLC5POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E51 CLC5SEL0 7:0 D1S[5:0]
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 440
...........continued
Address Name Bit Pos.
0x0E52 CLC5SEL1 7:0 D2S[5:0]
0x0E53 CLC5SEL2 7:0 D3S[5:0]
0x0E54 CLC5SEL3 7:0 D4S[5:0]
0x0E55 CLC5GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E56 CLC5GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E57 CLC5GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E58 CLC5GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E59 CLC6CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E5A CLC6POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E5B CLC6SEL0 7:0 D1S[5:0]
0x0E5C CLC6SEL1 7:0 D2S[5:0]
0x0E5D CLC6SEL2 7:0 D3S[5:0]
0x0E5E CLC6SEL3 7:0 D4S[5:0]
0x0E5F CLC6GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E60 CLC6GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E61 CLC6GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E62 CLC6GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E63 CLC7CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E64 CLC7POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E65 CLC7SEL0 7:0 D1S[5:0]
0x0E66 CLC7SEL1 7:0 D2S[5:0]
0x0E67 CLC7SEL2 7:0 D3S[5:0]
0x0E68 CLC7SEL3 7:0 D4S[5:0]
0x0E69 CLC7GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E6A CLC7GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E6B CLC7GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E6C CLC7GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E6D CLC8CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E6E CLC8POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E6F CLC8SEL0 7:0 D1S[5:0]
0x0E70 CLC8SEL1 7:0 D2S[5:0]
0x0E71 CLC8SEL2 7:0 D3S[5:0]
0x0E72 CLC8SEL3 7:0 D4S[5:0]
0x0E73 CLC8GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E74 CLC8GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E75 CLC8GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E76 CLC8GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E77 CLCDATA 7:0 MLC8OUT MLC7OUT MLC6OUT MLC5OUT MLC4OUT MLC3OUT MLC2OUT MLC1OUT
25.8 Register Definitions: Configurable Logic Cell
Long bit name prefixes for the CLC peripherals are shown in the table below. Refer to the "Long Bit
Names Section" for more information.
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 441
Table 25-2. CLC Bit Name Prefixes
Peripheral Bit Name Prefix
CLC1 LC1
CLC2 LC2
CLC3 LC3
CLC4 LC4
CLC5 LC5
CLC6 LC6
CLC7 LC7
CLC8 LC8
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 442
25.8.1 CLCxCON
Name:  CLCxCON
Address:  0xE27,0xE31,0xE3B,0xE45,0xE4F,0xE59,0xE63,0xE6D
Configurable Logic Cell Control Register
Bit 7 6 5 4 3 2 1 0
EN OUT INTP INTN MODE[2:0]
Access R/W RO R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bit 7 – EN
CLC Enable bit
Value Description
1Configurable logic cell is enabled and mixing signals
0Configurable logic cell is disabled and has logic zero output
Bit 5 – OUT
Logic cell output data, after LCPOL. Sampled from CLCxOUT
Bit 4 – INTP
Configurable Logic Cell Positive Edge Going Interrupt Enable bit
Value Description
1CLCxIF will be set when a rising edge occurs on CLCxOUT
0Rising edges on CLCxOUT have no effect on CLCxIF
Bit 3 – INTN
Configurable Logic Cell Negative Edge Going Interrupt Enable bit
Value Description
1CLCxIF will be set when a falling edge occurs on CLCxOUT
0Falling edges on CLCxOUT have no effect on CLCxIF
Bits 2:0 – MODE[2:0]
Configurable Logic Cell Functional Mode Selection bits
Value Description
111 Cell is 1-input transparent latch with Set and Reset
110 Cell is J-K flip-flop with Reset
101 Cell is 2-input D flip-flop with Reset
100 Cell is 1-input D flip-flop with Set and Reset
011 Cell is S-R latch
010 Cell is 4-input AND
001 Cell is OR-XOR
000 Cell is AND-OR
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 443
25.8.2 CLCxPOL
Name:  CLCxPOL
Address:  0xE28,0xE32,0xE3C,0xE46,0xE50,0xE5A,0xE64,0xE6E
Signal Polarity Control Register
Bit 7 6 5 4 3 2 1 0
POL G4POL G3POL G2POL G1POL
Access R/W R/W R/W R/W R/W
Reset 0 x x x x
Bit 7 – POL
CLCxOUT Output Polarity Control bit
Value Description
1The output of the logic cell is inverted
0The output of the logic cell is not inverted
Bits 0, 1, 2, 3 – GyPOL
Gate Output Polarity Control bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1The gate output is inverted when applied to the logic cell
0The output of the gate is not inverted
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 444
25.8.3 CLCxSEL0
Name:  CLCxSEL0
Address:  0xE29,0xE33,0xE3D,0xE47,0xE51,0xE5B,0xE65,0xE6F
Generic CLCx Data 1 Select Register
Bit 7 6 5 4 3 2 1 0
D1S[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset x x x x x x
Bits 5:0 – D1S[5:0]
CLCx Data1 Input Selection bits
Reset States: POR/BOR = xxxxxx
All Other Resets = uuuuuu
Value Description
nRefer to CLC Input Sources for input selections
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 445
25.8.4 CLCxSEL1
Name:  CLCxSEL1
Address:  0xE2A,0xE34,0xE3E,0xE48,0xE52,0xE5C,0xE66,0xE70
Generic CLCx Data 1 Select Register
Bit 7 6 5 4 3 2 1 0
D2S[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset x x x x x x
Bits 5:0 – D2S[5:0]
CLCx Data2 Input Selection bits
Reset States: POR/BOR = xxxxxx
All Other Resets = uuuuuu
Value Description
nRefer to CLC Input Sources for input selections
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 446
25.8.5 CLCxSEL2
Name:  CLCxSEL2
Address:  0xE2B,0xE35,0xE3F,0xE49,0xE53,0xE5D,0xE67,0xE71
Generic CLCx Data 1 Select Register
Bit 7 6 5 4 3 2 1 0
D3S[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset x x x x x x
Bits 5:0 – D3S[5:0]
CLCx Data3 Input Selection bits
Reset States: POR/BOR = xxxxxx
All Other Resets = uuuuuu
Value Description
nRefer to CLC Input Sources for input selections
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 447
25.8.6 CLCxSEL3
Name:  CLCxSEL3
Address:  0xE2C,0xE36,0xE40,0xE4A,0xE54,0xE5E,0xE68,0xE72
Generic CLCx Data 4 Select Register
Bit 7 6 5 4 3 2 1 0
D4S[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset x x x x x x
Bits 5:0 – D4S[5:0]
CLCx Data4 Input Selection bits
Reset States: POR/BOR = xxxxxx
All Other Resets = uuuuuu
Value Description
nRefer to CLC Input Sources for input selections
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 448
25.8.7 CLCxGLS0
Name:  CLCxGLS0
Address:  0xE2D,0xE37,0xE41,0xE4B,0xE55,0xE5F,0xE69,0xE73
CLCx Gate1 Logic Select Register
Bit 7 6 5 4 3 2 1 0
G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 1, 3, 5, 7 – G1DyT
dyT: Gate1 Data 'y' True (non-inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyT is gated into g1
0dyT is not gated into g1
Bits 0, 2, 4, 6 – G1DyN
dyN: Gate1 Data 'y' Negated (inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyN is gated into g1
0dyN is not gated into g1
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 449
25.8.8 CLCxGLS1
Name:  CLCxGLS1
Address:  0xE2E,0xE38,0xE42,0xE4C,0xE56,0xE60,0xE6A,0xE74
CLCx Gate2 Logic Select Register
Bit 7 6 5 4 3 2 1 0
G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 1, 3, 5, 7 – G2DyT
dyT: Gate2 Data 'y' True (non-inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyT is gated into g2
0dyT is not gated into g2
Bits 0, 2, 4, 6 – G2DyN
dyN: Gate2 Data 'y' Negated (inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyN is gated into g2
0dyN is not gated into g2
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 450
25.8.9 CLCxGLS2
Name:  CLCxGLS2
Address:  0xE2F,0xE39,0xE43,0xE4D,0xE57,0xE61,0xE6B,0xE75
CLCx Gate3 Logic Select Register
Bit 7 6 5 4 3 2 1 0
G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 1, 3, 5, 7 – G3DyT
dyT: Gate3 Data 'y' True (non-inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyT is gated into g3
0dyT is not gated into g3
Bits 0, 2, 4, 6 – G3DyN
dyN: Gate3 Data 'y' Negated (inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyN is gated into g3
0dyN is not gated into g3
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 451
25.8.10 CLCxGLS3
Name:  CLCxGLS3
Address:  0xE30,0xE3A,0xE44,0xE4E,0xE58,0xE62,0xE6C,0xE76
CLCx Gate4 Logic Select Register
Bit 7 6 5 4 3 2 1 0
G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 1, 3, 5, 7 – G4DyT
dyT: Gate4 Data 'y' True (non-inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyT is gated into g4
0dyT is not gated into g4
Bits 0, 2, 4, 6 – G4DyN
dyN: Gate4 Data 'y' Negated (inverted) bit
Reset States: Default = xxxx
POR/BOR = x
All Other Resets = u
Value Description
1dyN is gated into g4
0dyN is not gated into g4
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 452
25.8.11 CLCDATA
Name:  CLCDATA
Address:  0xE77
CLC Data Ouput Register
Mirror copy of
Bit 7 6 5 4 3 2 1 0
MLC8OUT MLC7OUT MLC6OUT MLC5OUT MLC4OUT MLC3OUT MLC2OUT MLC1OUT
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 0, 1, 2, 3, 4, 5, 6, 7 – MLCxOUT
Mirror copy of CLCx_out bit
Value Description
1CLCx_out is 1
0CLCx_out is 0
PIC18F26/45/46Q10
(CLC) Configurable Logic Cell
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 453
26. (DSM) Data Signal Modulator Module
The Data Signal Modulator (DSM) is a peripheral that allows the user to mix a data stream, also known
as a modulator signal, with a carrier signal to produce a modulated output.
Both the carrier and the modulator signals are supplied to the DSM module either internally, from the
output of a peripheral, or externally through an input pin.
The modulated output signal is generated by performing a logical “AND” operation of both the carrier and
modulator signals and then provided to the MDOUT pin.
The carrier signal is comprised of two distinct and separate signals. A Carrier High (CARH) signal and a
Carrier Low (CARL) signal. During the time in which the modulator (MOD) signal is in a logic high state,
the DSM mixes the CARH signal with the modulator signal. When the modulator signal is in a logic low
state, the DSM mixes the CARL signal with the modulator signal.
Using this method, the DSM can generate the following types of key modulation schemes:
Frequency-Shift Keying (FSK)
Phase-Shift Keying (PSK)
On-Off Keying (OOK)
Additionally, the following features are provided within the DSM module:
Carrier Synchronization
Carrier Source Polarity Select
Programmable Modulator Data
Modulated Output Polarity Select
Peripheral Module Disable, which provides the ability to place the DSM module in the lowest power
consumption mode
The figure below shows a simplified block diagram of the data signal modulator peripheral.
PIC18F26/45/46Q10
(DSM) Data Signal Modulator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 454
Figure 26-1. Simplified Block Diagram of the Data Signal Modulator
Rev. 10-000248E
8/7/2015
D
Q
D
Q
SYNC
SYNC
MDOPOL
MDCHPOL
MDCLPOL
MDCLSYNC
MDCHSYNC
CARL
CARH
MOD
MDCHS<2:0>
MDCLS<2:0>
Data Signal Modulator
1
0
1
0
000
See
MDCARH
Register
111
000
See
MDCARL
Register
111
MDSRCS<3:0>
0000
See
MDSRC
Register
1111
PPS
RxyPPS
PIC18F26/45/46Q10
(DSM) Data Signal Modulator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 455
26.1 DSM Operation
The DSM module can be enabled by setting the EN bit in the MDCON0 register. Clearing the EN bit,
disables the output of the module but retain the carrier and source signal selections. The module will
resume operation when the EN bit is set again. The output of the DSM module can be rerouted to several
pins using the RxyPPS register. When the EN bit is cleared the output pin is held low.
26.2 Modulator Signal Sources
The modulator signal can be supplied from the following sources selected with the SRCS bits:
Table 26-1. MDSRC Selection MUX Connections
SRCS[3:0] Connection
11000-11111 Reserved
10111 CLC8_out
10110 CLC7_out
10101 CLC6_out
10100 CLC5_out
10011 CLC4_out
10010 CLC3_out
10001 CLC2_out
10000 CLC1_out
01111 Reserved
01110 Reserved
01101 EUSART2 TX (TX/CK output)
01100 EUSART2 RX (DT output)
01011 MSSP2 - SDO
01010 MSSP1 - SDO
01001 EUSART1 TX (TX/CK output)
01000 EUSART1 RX (DT output)
00111 CMP2 OUT
00110 CMP1 OUT
00101 PWM4 OUT
00100 PWM3 OUT
00011 CCP2 OUT
00010 CCP1 OUT
00001 MDBIT
PIC18F26/45/46Q10
(DSM) Data Signal Modulator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 456
...........continued
SRCS[3:0] Connection
00000 Pin selected by MDSRCPPS
26.3 Carrier Signal Sources
The carrier high signal and carrier low signal can be supplied from the following sources.
The carrier high signal is selected by configuring the CHS bits.
Table 26-2. MDCARH Source Selections
MDCARH
CHS[2:0] Connection
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0111 PWM4 OUT
0110 PWM3 OUT
0101 CCP2 OUT
0100 CCP1 OUT
0011 CLKREF output
0010 HFINTOSC
0001 FOSC (system clock)
0000 Pin selected by MDCARHPPS
The carrier low signal is selected by configuring the CLS bits.
Table 26-3. MDCARL Source Selections
MDCARL
CLS[2:0] Connection
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
PIC18F26/45/46Q10
(DSM) Data Signal Modulator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 457
...........continued
MDCARL
CLS[2:0] Connection
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0111 PWM4 OUT
0110 PWM3 OUT
0101 CCP2 OUT
0100 CCP1 OUT
0011 CLKREF output
0010 HFINTOSC
0001 FOSC (system clock)
0000 Pin selected by MDCARLPPS
26.4 Carrier Synchronization
During the time when the DSM switches between carrier high and carrier low signal sources, the carrier
data in the modulated output signal can become truncated. To prevent this, the carrier signal can be
synchronized to the modulator signal. When synchronization is enabled, the carrier pulse that is being
mixed at the time of the transition is allowed to transition low before the DSM switches over to the next
carrier source.
Synchronization is enabled separately for the carrier high and carrier low signal sources. Synchronization
for the carrier high signal is enabled by setting the CHSYNC bit. Synchronization for the carrier low signal
is enabled by setting the CLSYNC bit.
The figures below show the timing diagrams of using various synchronization methods.
PIC18F26/45/46Q10
(DSM) Data Signal Modulator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 458
Figure 26-2. On Off Keying (OOK) Synchronization
modulator
carrier_high
carrier_low
MDCHSYNC = 1
MDCLSYNC = 0
MDCHSYNC = 1
MDCLSYNC = 1
MDCHSYNC = 0
MDCLSYNC = 0
MDCHSYNC = 0
MDCLSYNC = 1
Rev. 30-000144A
5/26/2017
Figure 26-3. No Synchronization (MDCHSYNC = 0, MDCLSYNC = 0)
MDCHSYNC = 0
MDCLSYNC = 0
modulator
carrier_high
carrier_low
Active Carrier carrier_high carrier_low carrier_low
carrier_high
State
Rev. 30-000145A
5/26/2017
Figure 26-4. Carrier High Synchronization (MDCHSYNC = 1, MDCLSYNC = 0)
MDCHSYNC = 1
MDCLSYNC = 0
modulator
carrier_high
carrier_low
Active Carrier
carrier_high carrier_low carrier_low
carrier_high
State
both both
Rev. 30-000146A
5/26/2017
PIC18F26/45/46Q10
(DSM) Data Signal Modulator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 459
Figure 26-5. Carrier Low Synchronization (MDCHSYNC = 0, MDCLSYNC = 1)
MDCHSYNC = 0
MDCLSYNC = 1
modulator
carrier_high
carrier_low
Active Carrier carrier_high carrier_low carrier_low
carrier_high
State
Rev. 30-000147A
5/26/2017
Figure 26-6. Full Synchronization (MDCHSYNC = 1, MDCLSYNC = 1)
MDCHSYNC = 1
MDCLSYNC = 1
modulator
carrier_high
carrier_low
Active Carrier carrier_high carrier_low CL
carrier_high
State
Falling edges
used to sync
Rev. 30-000148A
5/26/2017
26.5 Carrier Source Polarity Select
The signal provided from any selected input source for the carrier high and carrier low signals can be
inverted. Inverting the signal for the carrier high and low source is enabled by setting the CHPOL bit and
the CLPOL bit, respectively.
26.6 Programmable Modulator Data
The BIT control bit can be selected as the modulation source. This gives the user the ability to provide
software driven modulation.
26.7 Modulated Output Polarity
The modulated output signal provided on the DSM pin can also be inverted. Inverting the modulated
output signal is enabled by setting the OPOL bit.
26.8 Operation in Sleep Mode
The DSM can still operate during Sleep, if the carrier and modulator input sources are also still operable
during Sleep. Refer to “Power-Saving Operation Modes” for more details.
Related Links
6.4 Peripheral Operation in Power-Saving Modes
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26.9 Effects of a Reset
Upon any device Reset, the DSM module is disabled. The user’s firmware is responsible for initializing
the module before enabling the output. All the registers are reset to their default values.
26.10 Peripheral Module Disable
The DSM module can be completely disabled using the PMD module to achieve maximum power saving.
When the DSMMD bit of PMDx register is set, the DSM module is completely disabled. This puts the
module in its lowest power consumption state. When enabled again all the registers of the DSM module
default to POR status.
Related Links
7.4 Register Definitions: Peripheral Module Disable
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26.11 Register Summary - DSM
Address Name Bit Pos.
0x0F4C MDCON0 7:0 EN OUT OPOL BIT
0x0F4D MDCON1 7:0 CHPOL CHSYNC CLPOL CLSYNC
0x0F4E MDSRC 7:0 SRCS[4:0]
0x0F4F MDCARL 7:0 CLS[3:0]
0x0F50 MDCARH 7:0 CHS[3:0]
26.12 Register Definitions: Modulation Control
Long bit name prefixes for the modulation control peripherals are shown in the table below. Refer to the
"Long Bit Names Section" for more information.
Table 26-4. Modulation Control Long Bit Name Prefixes
Peripheral Bit Name Prefix
MD MD
Related Links
1.4.2.2 Long Bit Names
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26.12.1 MDCON0
Name:  MDCON0
Address:  0xF4C
Modulation Control Register 0
Bit 7 6 5 4 3 2 1 0
EN OUT OPOL BIT
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – EN Modulator Module Enable bit
Value Description
1Modulator module is enabled and mixing input signals
0Modulator module is disabled and has no output
Bit 5 – OUT Modulator Output bit
Displays the current output value of the modulator module.
Bit 4 – OPOL Modulator Output Polarity Select bit
Value Description
1Modulator output signal is inverted; idle high output
0Modulator output signal is not inverted; idle low output
Bit 0 – BIT Modulation Source Select Input bit
Allows software to manually set modulation source input to module
Note: 
1. The modulated output frequency can be greater and asynchronous from the clock that updates this
register bit, the bit value may not be valid for higher speed modulator or carrier signals.
2. MDBIT must be selected as the modulation source in the MDSRC register for this operation.
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26.12.2 MDCON1
Name:  MDCON1
Address:  0xF4D
Modulation Control Register 1
Bit 7 6 5 4 3 2 1 0
CHPOL CHSYNC CLPOL CLSYNC
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 5 – CHPOL Modulator High Carrier Polarity Select bit
Value Description
1Selected high carrier signal is inverted
0Selected high carrier signal is not inverted
Bit 4 – CHSYNC Modulator High Carrier Synchronization Enable bit
Value Description
1Modulator waits for a falling edge on the high time carrier signal before allowing a switch to
the low time carrier
0Modulator output is not synchronized to the high time carrier signal
Bit 1 – CLPOL Modulator Low Carrier Polarity Select bit
Value Description
1Selected low carrier signal is inverted
0Selected low carrier signal is not inverted
Bit 0 – CLSYNC Modulator Low Carrier Synchronization Enable bit
Value Description
1Modulator waits for a falling edge on the low time carrier signal before allowing a switch to
the high time carrier
0Modulator output is not synchronized to the low time carrier signal
Note: 
1. Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not
synchronized.
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26.12.3 MDCARH
Name:  MDCARH
Address:  0xF50
Modulation High Carrier Control Register
Bit 7 6 5 4 3 2 1 0
CHS[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – CHS[3:0] Modulator Carrier High Selection bits
Table 26-5. MDCARH Source Selections
MDCARH
CHS[2:0] Connection
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0111 PWM4 OUT
0110 PWM3 OUT
0101 CCP2 OUT
0100 CCP1 OUT
0011 CLKREF output
0010 HFINTOSC
0001 FOSC (system clock)
0000 Pin selected by MDCARHPPS
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26.12.4 MDCARL
Name:  MDCARL
Address:  0xF4F
Modulation Low Carrier Control Register
Bit 7 6 5 4 3 2 1 0
CLS[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – CLS[3:0] Modulator Carrier Low Input Selection bits
Table 26-6. MDCARL Source Selections
MDCARL
CLS[2:0] Connection
1111 CLC8_out
1110 CLC7_out
1101 CLC6_out
1100 CLC5_out
1011 CLC4_out
1010 CLC3_out
1001 CLC2_out
1000 CLC1_out
0111 PWM4 OUT
0110 PWM3 OUT
0101 CCP2 OUT
0100 CCP1 OUT
0011 CLKREF output
0010 HFINTOSC
0001 FOSC (system clock)
0000 Pin selected by MDCARLPPS
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26.12.5 MDSRC
Name:  MDSRC
Address:  0xF4E
Modulation Source Control Register
Bit 7 6 5 4 3 2 1 0
SRCS[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – SRCS[4:0] Modulator Source Selection bits
Table 26-7. MDSRC Selection MUX Connections
SRCS[3:0] Connection
11000-11111 Reserved
10111 CLC8_out
10110 CLC7_out
10101 CLC6_out
10100 CLC5_out
10011 CLC4_out
10010 CLC3_out
10001 CLC2_out
10000 CLC1_out
01111 Reserved
01110 Reserved
01101 EUSART2 TX (TX/CK output)
01100 EUSART2 RX (DT output)
01011 MSSP2 - SDO
01010 MSSP1 - SDO
01001 EUSART1 TX (TX/CK output)
01000 EUSART1 RX (DT output)
00111 CMP2 OUT
00110 CMP1 OUT
00101 PWM4 OUT
00100 PWM3 OUT
00011 CCP2 OUT
PIC18F26/45/46Q10
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...........continued
SRCS[3:0] Connection
00010 CCP1 OUT
00001 MDBIT
00000 Pin selected by MDSRCPPS
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27. (MSSP) Master Synchronous Serial Port Module
The Master Synchronous Serial Port (MSSP) module is a serial interface useful for communicating with
other peripheral or microcontroller devices. These peripheral devices may be serial EEPROMs, Shift
registers, display drivers, A/D converters, etc. The MSSP module can operate in one of two modes:
Serial Peripheral Interface (SPI)
Inter-Integrated Circuit (I2C)
The SPI interface supports the following modes and features:
Master mode
Slave mode
Clock Parity
Slave Select Synchronization (Slave mode only)
Daisy-chain connection of slave devices
The I2C interface supports the following modes and features:
Master mode
Slave mode
Byte NACKing (Slave mode)
Limited multi-master support
7-bit and 10-bit addressing
Start and Stop interrupts
Interrupt masking
Clock stretching
Bus collision detection
General call address matching
Address masking
Address Hold and Data Hold modes
Selectable SDA hold times
27.1 SPI Mode Overview
The Serial Peripheral Interface (SPI) bus is a synchronous serial data communication bus that operates
in Full-Duplex mode. Devices communicate in a master/slave environment where the master device
initiates the communication. A slave device is controlled through a Chip Select known as Slave Select.
The SPI bus specifies four signal connections:
Serial Clock (SCK)
Serial Data Out (SDO)
Serial Data In (SDI)
Slave Select (SS)
The following figure shows the block diagram of the MSSP module when operating in SPI mode.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
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Figure 27-1. MSSP Block Diagram (SPI mode)
( )
Read Write
Data Bus
SSPSR Reg
SSPM<3:0>
bit 0 Shift
Clock
SS Control
Enable
Edge
Select
Clock Select
T2_match
2
Edge
Select
2 (CKP, CKE)
4
TRIS bit
SDO
SSPxBUF Reg
SDI
SS
SCK
TOSC
Prescaler
4, 16, 64
Baud Rate
Generator
(SSPxADD)
PPS
PPS
PPS
PPS
SSPxDATPPS
RxyPPS
SSPxCLKPPS(2)
PPS
RxyPPS(1)
SSPxSSPPS
Note 1: Output selection for master mode
2: Input selection for slave and master mode
Rev. 30-000011A
3/31/2017
The SPI bus operates with a single master device and one or more slave devices. When multiple slave
devices are used, an independent Slave Select connection is required from the master device to each
slave device.
The figure below shows a typical connection between a master device and multiple slave devices.
The master selects only one slave at a time. Most slave devices have tri-state outputs so their output
signal appears disconnected from the bus when they are not selected.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
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Figure 27-2. SPI Master and Multiple Slave Connection
SPI Master SCK
SDO
SDI
General I/O
General I/O
General I/O
SCK
SDI
SDO
SS
SPI Slave
#1
SCK
SDI
SDO
SS
SPI Slave
#2
SCK
SDI
SDO
SS
SPI Slave
#3
Rev. 30-000012A
3/31/2017
27.1.1 SPI Mode Registers
The MSSP module has five registers for SPI mode operation. These are:
MSSP STATUS register (SSPxSTAT)
MSSP Control register 1 (SSPxCON1)
MSSP Control register 3 (SSPxCON3)
MSSP Data Buffer register (SSPxBUF)
MSSP Address register (SSPxADD)
MSSP Shift register (SSPSR)
(Not directly accessible)
SSPxCON1 and SSPxSTAT are the control and STATUS registers for SPI mode operation. The
SSPxCON1 register is readable and writable. The lower six bits of the SSPxSTAT are read-only. The
upper two bits of the SSPxSTAT are read/write.
One of the five SPI Master modes uses the SSPxADD value to determine the Baud Rate Generator clock
frequency. More information on the Baud Rate Generator is available in 27.7 Baud Rate Generator.
SSPSR is the Shift register used for shifting data in and out. SSPxBUF provides indirect access to the
SSPSR register. SSPxBUF is the Buffer register to which data bytes are written, and from which data
bytes are read.
In receive operations, SSPSR and SSPxBUF together create a buffered receiver. When SSPSR receives
a complete byte, it is transferred to SSPxBUF and the SSPxIF interrupt is set.
During transmission, the SSPxBUF is not buffered. A write to SSPxBUF will write to both SSPxBUF and
SSPSR.
27.2 SPI Mode Operation
Transmissions involve two Shift registers, eight bits in size, one in the master and one in the slave. With
either the master or the slave device, data is always shifted out one bit at a time, with the Most Significant
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
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bit (MSb) shifted out first. At the same time, a new Least Significant bit (LSb) is shifted into the same
register.
The following figure shows a typical connection between two processors configured as master and slave
devices.
Figure 27-3. SPI Master/Slave Connection
Serial Input Buffer
(BUF)
Shift Register
(SSPSR)
MSb LSb
SDO
SDI
Processor 1
SCK
SPI Master SSPM<3:0> = 00xx
Serial Input Buffer
(SSPxBUF)
Shift Register
Processor 2
SCK
SPI Slave SSPM<3:0> = 010x
Serial Clock
SS
Slave Select
General I/O (optional)
=1010
(SSPSR)
LSb
MSb
SDI
SDO
Rev/ 30-000013A
3/31/2017
Data is shifted out of both Shift registers on the programmed clock edge and latched on the opposite
edge of the clock.
The master device transmits information out on its SDO output pin, which is connected to and received by
the slave’s SDI input pin. The slave device transmits information out on its SDO output pin, which is
connected to and received by the master’s SDI input pin.
To begin communication the master device first sends out the clock signal. Both the master and the slave
devices should be configured for the same clock polarity.
The master device starts a transmission by sending out the MSb from its Shift register. The slave device
reads this bit from that same line and saves it into the LSb position of its Shift register.
During each SPI clock cycle, a full-duplex data transmission occurs. This means that while the master
device is sending out the MSb from its Shift register (on its SDO pin) and the slave device is reading this
bit and saving it as the LSb of its Shift register, the slave device is also sending out the MSb from its Shift
register (on its SDO pin) and the master device is reading this bit and saving it as the LSb of its Shift
register.
After eight bits have been shifted out, the master and slave have exchanged register values.
If there is more data to exchange, the Shift registers are loaded with new data and the process repeats
itself.
Whether the data is meaningful or not (dummy data), depends on the application software. This leads to
three scenarios for data transmission:
Master sends useful data and slave sends dummy data.
Master sends useful data and slave sends useful data.
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Master sends dummy data and slave sends useful data.
Transmissions may involve any number of clock cycles. When there is no more data to be transmitted,
the master stops sending the clock signal and it deselects the slave.
Every slave device connected to the bus that has not been selected through its slave select line must
disregard the clock and transmission signals and must not transmit out any data of its own.
When initializing the SPI several options need to be specified. This is done by programming the
appropriate control bits (SSPxCON1<5:0> and SSPxSTAT<7:6>). These control bits allow the following to
be specified:
Master mode (SCK is the clock output)
Slave mode (SCK is the clock input)
Clock Polarity (Idle state of SCK)
Data Input Sample Phase (middle or end of data output time)
Clock Edge (output data on rising/falling edge of SCK)
Clock Rate (Master mode only)
Slave Select mode (Slave mode only)
To enable the serial port the SSP Enable bit, SSPEN, must be set. To reset or reconfigure SPI mode,
clear the SSPEN bit, re-initialize the SSPxCONx registers and then set the SSPEN bit. The SDI, SDO,
SCK and SS serial port pins are selected with the PPS controls. For the pins to behave as the serial port
function, some must have their data direction bits (in the TRIS register) appropriately programmed as
follows:
SDI must have corresponding TRIS bit set
SDO must have corresponding TRIS bit cleared
SCK (Master mode) must have corresponding TRIS bit cleared
SCK (Slave mode) must have corresponding TRIS bit set
The RxyPPS and SSPxCLKPPS controls must select the same pin
SS must have corresponding TRIS bit set
Any serial port function that is not desired may be overridden by programming the corresponding data
direction (TRIS) register to the opposite value.
The MSSP consists of a transmit/receive shift register (SSPSR) and a buffer register (SSPxBUF). The
SSPSR shifts the data in and out of the device, MSb first. The SSPxBUF holds the data that was written
to the SSPSR until the received data is ready. Once the eight bits of data have been received, that byte is
moved to the SSPxBUF register. Then, the Buffer Full Detect bit, BF, and the Interrupt Flag bit, SSPxIF,
are set. This double-buffering of the received data (SSPxBUF) allows the next byte to start reception
before reading the data that was just received. Any write to the SSPxBUF register during transmission/
reception of data will be ignored and the write collision detect bit, WCOL, will be set. User software must
clear the WCOL bit to allow the following write(s) to the SSPxBUF register to complete successfully.
When the application software is expecting to receive valid data, the SSPxBUF should be read before the
next byte of data to transfer is written to the SSPxBUF. The Buffer Full bit, BF, indicates when SSPxBUF
has been loaded with the received data (transmission is complete). When the SSPxBUF is read, the BF
bit is cleared. This data may be irrelevant if the SPI is only a transmitter. Generally, the MSSP interrupt is
used to determine when the transmission/reception has completed. If the interrupt method is not going to
be used, then software polling can be done to ensure that a write collision does not occur.
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The SSPSR is not directly readable or writable and can only be accessed by addressing the SSPxBUF
register. Additionally, the SSPxSTAT register indicates the various Status conditions.
27.2.1 SPI Master Mode
The master can initiate the data transfer at any time because it controls the SCK line. The master
determines when the slave (Processor 2, Figure 27-3) is to broadcast data by the software protocol.
In Master mode, the data is transmitted/received as soon as the SSPxBUF register is written to. If the SPI
is only going to receive, the SDO output could be disabled (programmed as an input). The SSPSR
register will continue to shift in the signal present on the SDI pin at the programmed clock rate. As each
byte is received, it will be loaded into the SSPxBUF register as if a normal received byte (interrupts and
Status bits appropriately set).
The clock polarity is selected by appropriately programming the CKP bit and the CKE bit. This then,
would give waveforms for SPI communication as shown in Figure 27-4, Figure 27-6, Figure 27-7 and
Figure 27-8, where the MSB is transmitted first. In Master mode, the SPI clock rate (bit rate) is user
programmable to be one of the following:
FOSC/4 (or TCY)
FOSC/16 (or 4 * TCY)
FOSC/64 (or 16 * TCY)
Timer2 output/2
FOSC/(4 * (SSPxADD + 1))
Figure 27-4 shows the waveforms for Master mode.
When the CKE bit is set, the SDO data is valid before there is a clock edge on SCK. The change of the
input sample is shown based on the state of the SMP bit. The time when the SSPxBUF is loaded with the
received data is shown.
Important:  In Master mode the clock signal output to the SCK pin is also the clock signal input
to the peripheral. The pin selected for output with the RxyPPS register must also be selected as
the peripheral input with the SSPxCLKPPS register. The pin that is selected using the
SSPxCLKPPS register should also be made a digital I/O. This is done by clearing the
corresponding ANSEL bit.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
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Figure 27-4. SPI Mode Waveform (Master Mode)
SCK
(CKP = 0
SCK
(CKP = 1
SCK
(CKP = 0
SCK
(CKP = 1
4 Clock
Modes
Input
Sample
Input
Sample
SDI
bit 7 bit 0
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
bit 7
SDI
SSPxIF
(SMP = 1)
(SMP = 0)
(SMP = 1)
CKE = 1)
CKE = 0)
CKE = 1)
CKE = 0)
(SMP = 0)
Write to
SSPxBUF
SSPSR to
SSPxBUF
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
(CKE = 0)
(CKE = 1)
bit 0
Rev. 30-000014A
3/13/2017
27.2.2 SPI Slave Mode
In Slave mode, the data is transmitted and received as external clock pulses appear on SCK. When the
last bit is latched, the SSPxIF Interrupt Flag bit is set.
Before enabling the module in SPI Slave mode, the clock line must match the proper Idle state. The clock
line can be observed by reading the SCK pin. The Idle state is determined by the CKP bit.
While in Slave mode, the external clock is supplied by the external clock source on the SCK pin. This
external clock must meet the minimum high and low times as specified in the electrical specifications.
While in Sleep mode, the slave can transmit/receive data. The Shift register is clocked from the SCK pin
input and when a byte is received, the device will generate an interrupt. If enabled, the device will wake-
up from Sleep.
27.2.3 Daisy-Chain Configuration
The SPI bus can sometimes be connected in a daisy-chain configuration. The first slave output is
connected to the second slave input, the second slave output is connected to the third slave input, and so
on. The final slave output is connected to the master input. Each slave sends out, during a second group
of clock pulses, an exact copy of what was received during the first group of clock pulses. The whole
PIC18F26/45/46Q10
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chain acts as one large communication shift register. The daisy-chain feature only requires a single Slave
Select line from the master device.
The following figure shows the block diagram of a typical daisy-chain connection when operating in SPI
mode.
Figure 27-5. SPI Daisy-Chain Connection
SPI Master SCK
SDO
SDI
General I/O
SCK
SDI
SDO
SS
SPI Slave
#1
SCK
SDI
SDO
SS
SPI Slave
#2
SCK
SDI
SDO
SS
SPI Slave
#3
Rev. 30-000015A
3/31/2017
In a daisy-chain configuration, only the most recent byte on the bus is required by the slave. Setting the
BOEN bit will enable writes to the SSPxBUF register, even if the previous byte has not been read. This
allows the software to ignore data that may not apply to it.
27.2.4 Slave Select Synchronization
The Slave Select can also be used to synchronize communication. The Slave Select line is held high until
the master device is ready to communicate. When the Slave Select line is pulled low, the slave knows
that a new transmission is starting.
If the slave fails to receive the communication properly, it will be reset at the end of the transmission,
when the Slave Select line returns to a high state. The slave is then ready to receive a new transmission
when the Slave Select line is pulled low again. If the Slave Select line is not used, there is a risk that the
slave will eventually become out of sync with the master. If the slave misses a bit, it will always be one bit
off in future transmissions. Use of the Slave Select line allows the slave and master to align themselves at
the beginning of each transmission.
The SS pin allows a Synchronous Slave mode. The SPI must be in Slave mode with SS pin control
enabled (SSPM = 0100).
When the SS pin is low, transmission and reception are enabled and the SDO pin is driven.
When the SS pin goes high, the SDO pin is no longer driven, even if in the middle of a transmitted byte
and becomes a floating output. External pull-up/pull-down resistors may be desirable depending on the
application.
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Note: 
1. When the SPI is in Slave mode with SS pin control enabled (SSPM = 0100), the SPI module will
reset if the SS pin is set to VDD.
2. When the SPI is used in Slave mode with CKE set; the user must enable SS pin control.
3. While operated in SPI Slave mode the SMP bit must remain clear.
When the SPI module resets, the bit counter is forced to ‘0’. This can be done by either forcing the SS pin
to a high level or clearing the SSPEN bit.
Figure 27-6. Slave Select Synchronous Waveform
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit 7
SDO bit 7 bit 6 bit 7
SSPxIF
Interrupt
CKE = 0)
CKE = 0)
Write to
SSPxBUF
SSPSR to
SSPxBUF
SS
Flag
bit 0
bit 7
bit 0
bit 6
SSPxBUF to
SSPSR
Shift register SSPSR
and bit count are reset
Rev. 30-000016A
4/10/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 477
Figure 27-7. SPI Mode Waveform (Slave Mode with CKE = 0)
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit 7
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SSPxIF
Interrupt
CKE = 0)
CKE = 0)
Write to
SSPxBUF
SSPSR to
SSPxBUF
SS
Flag
Optional
bit 0
detection active
Write Collision
Valid
Rev. 30-000017A
4/3/2017
Figure 27-8. SPI Mode Waveform (Slave Mode with CKE = 1)
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit 7 bit 0
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SSPxIF
Interrupt
CKE = 1)
CKE = 1)
Write to
SSPxBUF
SSPSR to
SSPxBUF
SS
Flag
Not Optional
Write Collision
detection active
Valid
Rev. 30-000018A
4/1/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 478
27.2.5 SPI Operation in Sleep Mode
In SPI Master mode, module clocks may be operating at a different speed than when in Full-Power mode;
in the case of the Sleep mode, all clocks are halted.
Special care must be taken by the user when the MSSP clock is much faster than the system clock.
In Slave mode, when MSSP interrupts are enabled, after the master completes sending data, an MSSP
interrupt will wake the controller from Sleep.
If an exit from Sleep mode is not desired, MSSP interrupts should be disabled.
In SPI Master mode, when the Sleep mode is selected, all module clocks are halted and the
transmission/reception will remain in that state until the device wakes. After the device returns to Run
mode, the module will resume transmitting and receiving data.
In SPI Slave mode, the SPI Transmit/Receive Shift register operates asynchronously to the device. This
allows the device to be placed in Sleep mode and data to be shifted into the SPI Transmit/Receive Shift
register. When all eight bits have been received, the MSSP interrupt flag bit will be set and if enabled, will
wake the device.
27.3 I2C Mode Overview
The Inter-Integrated Circuit (I2C) bus is a multi-master serial data communication bus. Devices
communicate in a master/slave environment where the master devices initiate the communication. A
slave device is controlled through addressing. The following two diagrams show block diagrams of the I2C
Master and Slave modes, respectively.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 479
Figure 27-9. MSSP Block Diagram (I2C Master mode)
Read Write
SSPSR
Start bit, Stop bit,
Start bit detect,
SSPxBUF
Internal
data bus
Set/Reset: S, P, SSPxSTAT, WCOL, SSPOV
Shift
Clock
MSb LSb
SDA
Acknowledge
Generate (SSPxCON2)
Stop bit detect
Write collision detect
Clock arbitration
State counter for
end of XMIT/RCV
SCL
SCL in
Bus Collision
SDA in
Receive Enable (RCEN)
Clock Cntl
Clock arbitrate/BCOL detect
(Hold off clock source)
[SSPM<3:0>]
Baud Rate
Reset SEN, PEN (SSPxCON2)
Generator
(SSPxADD)
Address Match detect
Set SSP1IF, BCL1IF
PPS
SSPxDATPPS(1)
PPS
Note 1: SDA pin selections must be the same for input and output
2: SCL pin selections must be the same for input and output
PPS
RxyPPS(1)
PPS
SSPxCLKPPS(2)
RxyPPS(1)
RxyPPS(2)
Rev. 30-000019A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 480
Figure 27-10. MSSP Block Diagram (I2C Slave mode)
Read Write
SSPSR Reg
Match Detect
SSPxADD Reg
Start and
Stop bit Detect
SSPxBUF Reg
Internal
Data Bus
Addr Match
Set, Reset
S, P bits
(SSPxSTAT Reg)
SCL
Shift
Clock
MSb LSb
SSPxMSK Reg
PPS
PPS
SSPxCLKPPS(2)
RxyPPS(2)
Clock
Stretching
SDA
PPS
PPS
SSPxDATPPS(1)
RxyPPS(1)
Note 1: SDA pin selections must be the same for input and output
2: SCL pin selections must be the same for input and output
Rev. 30-000020A
4/3/2017
The I2C bus specifies two signal connections:
Serial Clock (SCL)
Serial Data (SDA)
Both the SCL and SDA connections are bidirectional open-drain lines, each requiring pull-up resistors for
the supply voltage. Pulling the line to ground is considered a logical zero and letting the line float is
considered a logical one.
The following diagram shows a typical connection between two processors configured as master and
slave devices.
Figure 27-11. I2C Master/
Slave Connection
Master
SCL
SDA
SCL
SDA
Slave
VDD
VDD
Rev. 30-000021A
4/3/2017
The I2C bus can operate with one or more master devices and one or more slave devices.
There are four potential modes of operation for a given device:
Master Transmit mode
(master is transmitting data to a slave)
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 481
Master Receive mode
(master is receiving data from a slave)
Slave Transmit mode
(slave is transmitting data to a master)
Slave Receive mode
(slave is receiving data from the master)
To begin communication, a master device starts out in Master Transmit mode. The master device sends
out a Start bit followed by the address byte of the slave it intends to communicate with. This is followed by
a single Read/Write bit, which determines whether the master intends to transmit to or receive data from
the slave device.
If the requested slave exists on the bus, it will respond with an Acknowledge bit, otherwise known as an
ACK. The master then continues in either Transmit mode or Receive mode and the slave continues in the
complement, either in Receive mode or Transmit mode, respectively.
A Start bit is indicated by a high-to-low transition of the SDA line while the SCL line is held high. Address
and data bytes are sent out, Most Significant bit (MSb) first. The Read/Write bit is sent out as a logical
one when the master intends to read data from the slave, and is sent out as a logical zero when it intends
to write data to the slave.
The Acknowledge bit (ACK) is an active-low signal, which holds the SDA line low to indicate to the
transmitter that the slave device has received the transmitted data and is ready to receive more.
The transition of a data bit is always performed while the SCL line is held low. Transitions that occur while
the SCL line is held high are used to indicate Start and Stop bits.
If the master intends to write to the slave, then it repeatedly sends out a byte of data, with the slave
responding after each byte with an ACK bit. In this example, the master device is in Master Transmit
mode and the slave is in Slave Receive mode.
If the master intends to read from the slave, then it repeatedly receives a byte of data from the slave, and
responds after each byte with an ACK bit. In this example, the master device is in Master Receive mode
and the slave is Slave Transmit mode.
On the last byte of data communicated, the master device may end the transmission by sending a Stop
bit. If the master device is in Receive mode, it sends the Stop bit in place of the last ACK bit. A Stop bit is
indicated by a low-to-high transition of the SDA line while the SCL line is held high.
In some cases, the master may want to maintain control of the bus and re-initiate another transmission. If
so, the master device may send another Start bit in place of the Stop bit or last ACK bit when it is in
Receive mode.
The I2C bus specifies three message protocols:
Single message where a master writes data to a slave.
Single message where a master reads data from a slave.
Combined message where a master initiates a minimum of two writes, or two reads, or a combination
of writes and reads, to one or more slaves.
When one device is transmitting a logical one, or letting the line float, and a second device is transmitting
a logical zero, or holding the line low, the first device can detect that the line is not a logical one. This
detection, when used on the SCL line, is called clock stretching. Clock stretching gives slave devices a
mechanism to control the flow of data. When this detection is used on the SDA line, it is called arbitration.
Arbitration ensures that there is only one master device communicating at any single time.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 482
27.3.1 Register Definitions: I2C Mode
The MSSPx module has seven registers for I2C operation.
These are:
MSSP Status register (SSPxSTAT)
MSSP Control register 1 (SSPxCON1)
MSSP Control register 2 (SSPxCON2)
MSSP Control register 3 (SSPxCON3)
Serial Receive/Transmit Buffer register (SSPxBUF)
MSSP Address register (SSPxADD)
I2C Slave Address Mask register (SSPxMSK)
MSSP Shift register (SSPSR) – not directly accessible
SSPxCON1, SSPxCON2, SSPxCON3 and SSPxSTAT are the Control and STATUS registers in I2C mode
operation. The SSPxCON1, SSPxCON2, and SSPxCON3 registers are readable and writable. The lower
six bits of the SSPxSTAT are read-only. The upper two bits of the SSPxSTAT are read/write. SSPSR is
the Shift register used for shifting data in or out. SSPxBUF is the buffer register to which data bytes are
written to or read from. SSPxADD contains the slave device address when the MSSP is configured in I2C
Slave mode. When the MSSP is configured in Master mode, the lower seven bits of SSPxADD act as the
Baud Rate Generator reload value.
SSPxMSK holds the slave address mask value when the module is configured for 7-Bit Address Masking
mode. While it is a separate register, it shares the same SFR address as SSPxADD; it is only accessible
when the SSPM<3:0> bits are specifically set to permit access. In receive operations, SSPSR and
SSPxBUF together, create a double-buffered receiver. When SSPSR receives a complete byte, it is
transferred to SSPxBUF and the SSPxIF interrupt is set. During transmission, the SSPxBUF is not
double-buffered. A write to SSPxBUF will write to both SSPxBUF and SSPSR.
27.4 I2C Mode Operation
All MSSP I2C communication is byte oriented and shifted out MSb first. Six SFR registers and two
interrupt flags interface the module with the PIC® microcontroller and user software. Two pins, SDA and
SCL, are exercised by the module to communicate with other external I2C devices.
27.4.1 Clock Stretching
When a slave device has not completed processing data, it can delay the transfer of more data through
the process of clock stretching. An addressed slave device may hold the SCL clock line low after
receiving or sending a bit, indicating that it is not yet ready to continue. The master that is communicating
with the slave will attempt to raise the SCL line in order to transfer the next bit, but will detect that the
clock line has not yet been released. Because the SCL connection is open-drain, the slave has the ability
to hold that line low until it is ready to continue communicating.
Clock stretching allows receivers that cannot keep up with a transmitter to control the flow of incoming
data.
27.4.2 Arbitration
Each master device must monitor the bus for Start and Stop bits. If the device detects that the bus is
busy, it cannot begin a new message until the bus returns to an Idle state.
However, two master devices may try to initiate a transmission on or about the same time. When this
occurs, the process of arbitration begins. Each transmitter checks the level of the SDA data line and
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 483
compares it to the level that it expects to find. The first transmitter to observe that the two levels do not
match, loses arbitration, and must stop transmitting on the SDA line.
For example, if one transmitter holds the SDA line to a logical one (lets it float) and a second transmitter
holds it to a logical zero (pulls it low), the result is that the SDA line will be low. The first transmitter then
observes that the level of the line is different than expected and concludes that another transmitter is
communicating.
The first transmitter to notice this difference is the one that loses arbitration and must stop driving the
SDA line. If this transmitter is also a master device, it also must stop driving the SCL line. It then can
monitor the lines for a Stop condition before trying to reissue its transmission. In the meantime, the other
device that has not noticed any difference between the expected and actual levels on the SDA line
continues with its original transmission. It can do so without any complications, because so far, the
transmission appears exactly as expected with no other transmitter disturbing the message.
Slave Transmit mode can also be arbitrated, when a master addresses multiple slaves, but this is less
common.
If two master devices are sending a message to two different slave devices at the address stage, the
master sending the lower slave address always wins arbitration. When two master devices send
messages to the same slave address, and addresses can sometimes refer to multiple slaves, the
arbitration process must continue into the data stage.
Arbitration usually occurs very rarely, but it is a necessary process for proper multi-master support.
27.4.3 Byte Format
All communication in I2C is done in 9-bit segments. A byte is sent from a master to a slave or vice versa,
followed by an Acknowledge bit sent back. After the eighth falling edge of the SCL line, the device
outputting data on the SDA changes that pin to an input and reads in an acknowledge value on the next
clock pulse.
The clock signal, SCL, is provided by the master. Data is valid to change while the SCL signal is low, and
sampled on the rising edge of the clock. Changes on the SDA line while the SCL line is high define
special conditions on the bus, explained below.
27.4.4 Definition of I2C Terminology
There is language and terminology in the description of I2C communication that have definitions specific
to I2C. That word usage is defined below and may be used in the rest of this document without
explanation. This table was adapted from the Philips I2C specification.
TERM Description
Transmitter The device that shifts data out onto the bus.
Receiver The device that shifts data in from the bus.
Master The device that initiates a transfer, generates clock signals and terminates a
transfer.
Slave The device addressed by the master.
Multi-master A bus with more than one device that can initiate data transfers.
Arbitration Procedure to ensure that only one master at a time controls the bus. Winning
arbitration ensures that the message is not corrupted.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 484
...........continued
TERM Description
Synchronization Procedure to synchronize the clocks of two or more devices on the bus.
Idle No master is controlling the bus, and both SDA and SCL lines are high.
Active Any time one or more master devices are controlling the bus.
Addressed Slave Slave device that has received a matching address and is actively being clocked by
a master.
Matching Address Address byte that is clocked into a slave that matches the value stored in SSPxADD.
Write Request Slave receives a matching address with R/W bit clear, and is ready to clock in data.
Read Request Master sends an address byte with the R/W bit set, indicating that it wishes to clock
data out of the Slave. This data is the next and all following bytes until a Restart or
Stop.
Clock Stretching When a device on the bus hold SCL low to stall communication.
Bus Collision Any time the SDA line is sampled low by the module while it is outputting and
expected high state.
27.4.5 SDA and SCL Pins
Selection of any I2C mode with the SSPEN bit set, forces the SCL and SDA pins to be open-drain. These
pins should be set by the user to inputs by setting the appropriate TRIS bits.
Note: 
1. SDA is tied to output zero when an I2C mode is enabled.
2. Any device pin can be selected for SDA and SCL functions with the PPS peripheral. These
functions are bidirectional. The SDA input is selected with the SSPxDATPPS registers. The SCL
input is selected with the SSPxCLKPPS registers. Outputs are selected with the RxyPPS registers.
It is the user’s responsibility to make the selections so that both the input and the output for each
function is on the same pin.
27.4.6 SDA Hold Time
The hold time of the SDA pin is selected by the SDAHT bit. Hold time is the time SDA is held valid after
the falling edge of SCL. Setting the SDAHT bit selects a longer 300 ns minimum hold time and may help
on buses with large capacitance.
I2C Bus Terms
27.4.7 Start Condition
The I2C specification defines a Start condition as a transition of SDA from a high to a low state while SCL
line is high. A Start condition is always generated by the master and signifies the transition of the bus
from an Idle to an Active state. Figure 27-12 shows wave forms for Start and Stop conditions.
A bus collision can occur on a Start condition if the module samples the SDA line low before asserting it
low. This does not conform to the I2C Specification that states no bus collision can occur on a Start.
27.4.8 Stop Condition
A Stop condition is a transition of the SDA line from low-to-high state while the SCL line is high.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 485
Important:  At least one SCL low time must appear before a Stop is valid, therefore, if the SDA
line goes low then high again while the SCL line stays high, only the Start condition is detected.
Figure 27-12. I2C Start and Stop Conditions
SDA
SCL
P
Stop
Condition
S
Start
Condition
Change of
Data Allowed
Change of
Data Allowed
Rev. 30-000022A
4/3/2017
27.4.9 Restart Condition
A Restart is valid any time that a Stop would be valid. A master can issue a Restart if it wishes to hold the
bus after terminating the current transfer. A Restart has the same effect on the slave that a Start would,
resetting all slave logic and preparing it to clock in an address. The master may want to address the
same or another slave. Figure 27-13 shows the wave form for a Restart condition.
In 10-bit Addressing Slave mode a Restart is required for the master to clock data out of the addressed
slave. Once a slave has been fully addressed, matching both high and low address bytes, the master can
issue a Restart and the high address byte with the R/W bit set. The slave logic will then hold the clock
and prepare to clock out data.
After a full match with R/W clear in 10-bit mode, a prior match flag is set and maintained until a Stop
condition, a high address with R/W clear, or high address match fails.
Figure 27-13. I2C Restart Condition
Restart
Condition
Sr
Change of
Data Allowed
Change of
Data Allowed
Rev. 30-000023A
4/3/2017
27.4.10 Start/Stop Condition Interrupt Masking
The SCIE and PCIE bits can enable the generation of an interrupt in Slave modes that do not typically
support this function. These bits will have no effect in Slave modes where interrupt on Start and Stop
detect are already enabled.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 486
27.4.11 Acknowledge Sequence
The ninth SCL pulse for any transferred byte in I2C is dedicated as an Acknowledge. It allows receiving
devices to respond back to the transmitter by pulling the SDA line low. The transmitter must release
control of the line during this time to shift in the response. The Acknowledge (ACK) is an active-low
signal, pulling the SDA line low indicates to the transmitter that the device has received the transmitted
data and is ready to receive more.
The result of an ACK is placed in the ACKSTAT bit.
Slave software, when the AHEN and DHEN bits are set, allow the user to set the ACK value sent back to
the transmitter. The ACKDT bit is set/cleared to determine the response.
Slave hardware will generate an ACK response if both the AHEN and DHEN bits are clear. However, tf
the BF bit or the SSPOV bit are set when a byte is received then the ACK will not be sent by the slave.
When the module is addressed, after the eighth falling edge of SCL on the bus, the ACKTIM bit is set.
The ACKTIM bit indicates the acknowledge time of the active bus. The ACKTIM Status bit is only active
when either the AHEN bit or DHEN bit is enabled.
27.5 I2C Slave Mode Operation
The MSSP Slave mode operates in one of four modes selected by the SSPM bits. The modes can be
divided into 7-bit and 10-bit Addressing mode. 10-bit Addressing modes operate the same as 7-bit with
some additional overhead for handling the larger addresses.
Modes with Start and Stop bit interrupts operate the same as the other modes with SSPxIF additionally
getting set upon detection of a Start, Restart, or Stop condition.
27.5.1 Slave Mode Addresses
The SSPxADD register contains the Slave mode address. The first byte received after a Start or Restart
condition is compared against the value stored in this register. If the byte matches, the value is loaded
into the SSPxBUF register and an interrupt is generated. If the value does not match, the module goes
idle and no indication is given to the software that anything happened.
The SSPxMSK register affects the address matching process. See 27.5.9 SSP Mask Register for more
information.
27.5.1.1 I2C Slave 7-bit Addressing Mode
In 7-bit Addressing mode, the LSb of the received data byte is ignored when determining if there is an
address match.
27.5.1.2 I2C Slave 10-bit Addressing Mode
In 10-bit Addressing mode, the first received byte is compared to the binary value of ‘1 1 1 1 0 A9 A8 0’.
A9 and A8 are the two MSb’s of the 10-bit address and stored in bits 2 and 1 of the SSPxADD register.
After the acknowledge of the high byte the UA bit is set and SCL is held low until the user updates
SSPxADD with the low address. The low address byte is clocked in and all eight bits are compared to the
low address value in SSPxADD. Even if there is not an address match; SSPxIF and UA are set, and SCL
is held low until SSPxADD is updated to receive a high byte again. When SSPxADD is updated the UA bit
is cleared. This ensures the module is ready to receive the high address byte on the next communication.
A high and low address match as a write request is required at the start of all 10-bit addressing
communication. A transmission can be initiated by issuing a Restart once the slave is addressed, and
clocking in the high address with the R/W bit set. The slave hardware will then acknowledge the read
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 487
request and prepare to clock out data. This is only valid for a slave after it has received a complete high
and low address byte match.
27.5.2 Slave Reception
When the R/W bit of a matching received address byte is clear, the R/W bit is cleared. The received
address is loaded into the SSPxBUF register and acknowledged.
When the overflow condition exists for a received address, then Not Acknowledge (NACK) is given. An
overflow condition is defined as either bit BF is set, or bit SSPOV is set. The BOEN bit modifies this
operation. For more information see SSPxCON3.
An MSSP interrupt is generated for each transferred data byte. Flag bit, SSPxIF, must be cleared by
software.
When the SEN bit is set, SCL will be held low (clock stretch) following each received byte. The clock must
be released by setting the CKP bit, except sometimes in 10-bit mode. See 27.5.6.2 10-bit Addressing
Mode for more detail.
27.5.2.1 7-bit Addressing Reception
This section describes a standard sequence of events for the MSSP module configured as an I2C slave in
7-bit Addressing mode. Figure 27-14 and Figure 27-15 is used as a visual reference for this description.
This is a step by step process of what typically must be done to accomplish I2C communication.
1. Start bit detected.
2. S bit is set; SSPxIF is set if interrupt on Start detect is enabled.
3. Matching address with R/W bit clear is received.
4. The slave pulls SDA low sending an ACK to the master, and sets SSPxIF bit.
5. Software clears the SSPxIF bit.
6. Software reads received address from SSPxBUF clearing the BF flag.
7. If SEN = 1; Slave software sets CKP bit to release the SCL line.
8. The master clocks out a data byte.
9. Slave drives SDA low sending an ACK to the master, and sets SSPxIF bit.
10. Software clears SSPxIF.
11. Software reads the received byte from SSPxBUF clearing BF.
12. Steps 8-12 are repeated for all received bytes from the master.
13. Master sends Stop condition, setting P bit, and the bus goes idle.
27.5.2.2 7-bit Reception with AHEN and DHEN
Slave device reception with AHEN and DHEN set operate the same as without these options with extra
interrupts and clock stretching added after the eighth falling edge of SCL. These additional interrupts
allow the slave software to decide whether it wants to ACK the receive address or data byte, rather than
the hardware. This functionality adds support for PMBus that was not present on previous versions of
this module.
This list describes the steps that need to be taken by slave software to use these options for I2C
communication. Figure 27-16 displays a module using both address and data holding. Figure 27-17
includes the operation with the SEN bit of the SSPxCON2 register set.
1. S bit is set; SSPxIF is set if interrupt on Start detect is enabled.
2. Matching address with R/W bit clear is clocked in. SSPxIF is set and CKP cleared after the eighth
falling edge of SCL.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 488
3. Slave clears the SSPxIF.
4. Slave can look at the ACKTIM bit to determine if the SSPxIF was after or before the ACK.
5. Slave reads the address value from SSPxBUF, clearing the BF flag.
6. Slave sets ACK value clocked out to the master by setting ACKDT.
7. Slave releases the clock by setting CKP.
8. SSPxIF is set after an ACK, not after a NACK.
9. If SEN = 1, the slave hardware will stretch the clock after the ACK.
10. Slave clears SSPxIF.
Important:  SSPxIF is still set after the ninth falling edge of SCL even if there is no clock
stretching and BF has been cleared. Only if NACK is sent to master is SSPxIF not set
11. SSPxIF set and CKP cleared after eighth falling edge of SCL for a received data byte.
12. Slave looks at ACKTIM bit to determine the source of the interrupt.
13. Slave reads the received data from SSPxBUF clearing BF.
14. Steps 7-14 are the same for each received data byte.
15. Communication is ended by either the slave sending an ACK = 1, or the master sending a Stop
condition. If a Stop is sent and Interrupt on Stop Detect is disabled, the slave will only know by
polling the P bit.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 489
Figure 27-14. I2C Slave, 7-bit Address, Reception (SEN = 0, AHEN = 0, DHEN = 0)rotatethispage90
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PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 490
Figure 27-15. I2C Slave, 7-bit Address, Reception (SEN = 1, AHEN = 0, DHEN = 0)rotatethispage90
SEN SEN
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0SDA
SCL 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P
SSPxIF set on 9th
SCL is not held
CKP is written to ‘1’ in software,
CKP is written to ‘1’ in software,
ACK
low because
falling edge of SCL
releasing SCL
ACK is not sent.
Bus Master sends
CKP
SSPOV
BF
SSPxIF
SSPOV set because
SSPxBUF is still full.
Cleared by software
First byte
of dat a is
avai labl e
in SSPx BUF
ACK=1
Cleared by software
SSPxBUF is read
Clock is held low until CKP is set to ‘1
releasing SCL
Stop condition
S
ACK
ACK
Receive Address Receive Data Receive Data
R/W=0
Rev. 30-000025A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 491
Figure 27-16. I2C Slave, 7-bit Address, Reception (SEN = 0, AHEN = 1, DHEN = 1)rotatethispage90
Receiving Address Receiving Data Received Data
P
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
BF
CKP
S
P
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8
Master sends
Stop condition
S
Data is read from SSPxBUF
Cleared by software
SSPxIF is set on
9th falling edge of
SCL, after ACK
CKP set by software,
SCL is released
Slave software
9
ACKTIM cleared by
hardware in 9th
rising edge of SCL
sets ACKDT to
not ACK
When DHEN=1:
CKP is cleared by
hardware on 8th falling
edge of SCL
Slave software
clears ACKDT to
ACK the received
byte
ACKTIM set by hardware
on 8th falling edge of SCL
When AHEN=1:
CKP is cleared by hardware
and SCL is stretched
Address is
read from
SSBUF
ACKTIM set by hardware
on 8th falling edge of SCL
ACK
Master Releases SDA
to slave for ACK sequence
No interrupt
after not ACK
from Slave
ACK=1
ACK
ACKDT
ACKTIM
SSPxIF
If AHEN = 1:
SSPxIF is set
Rev. 30-000026A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 492
Figure 27-17. I2C Slave, 7-bit Address, Reception (SEN = 1, AHEN = 1, DHEN = 1)rotatethispage90
Receiving Address Receive Data Receive Data
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
SSPxIF
BF
ACKDT
CKP
S
P
ACK
S1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
ACK
ACK
Cleared by software
ACKTIM is cleared by hardware
SSPxBUF can be
Set by software,
read any time before
next byte is loaded
release SCL
on 9th rising edge of SCL
Received
address is loaded into
SSPxBUF
Slave software clears
ACKDT to ACK
R/W = 0Master releases
SDA to slave for ACK sequence
the received byte
When AHEN = 1;
on the 8th falling edge
of SCL of an address
byte, CKP is cleared
ACKTIM is set by hardware
on 8th falling edge of SCL
When DHEN = 1;
on the 8th falling edge
of SCL of a received
data byte, CKP is cleared
Received data is
available on SSPxBUF
Slave sends
not ACK
CKP is not cleared
if not ACK
P
Master sends
Stop condition
No interrupt after
if not ACK
from Slave
ACKTIM
Rev. 30-000027A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 493
27.5.3 Slave Transmission
When the R/W bit of the incoming address byte is set and an address match occurs, the R/W bit is set.
The received address is loaded into the SSPxBUF register, and an ACK pulse is sent by the slave on the
ninth bit.
Following the ACK, slave hardware clears the CKP bit and the SCL pin is held low (see 27.5.6 Clock
Stretchingfor more detail). By stretching the clock, the master will be unable to assert another clock pulse
until the slave is done preparing the transmit data.
The transmit data must be loaded into the SSPxBUF register, which also loads the SSPSR register. Then
the SCL pin should be released by setting the CKP bit. The eight data bits are shifted out on the falling
edge of the SCL input. This ensures that the SDA signal is valid during the SCL high time.
The ACK pulse from the master receiver is latched on the rising edge of the ninth SCL input pulse. This
ACK value is copied to the ACKSTAT bit. If ACKSTAT is set (not ACK), then the data transfer is complete.
In this case, when the not ACK is latched by the slave, the slave goes idle and waits for another
occurrence of the Start bit. If the SDA line was low (ACK), the next transmit data must be loaded into the
SSPxBUF register. Again, the SCL pin must be released by setting bit CKP.
An MSSP interrupt is generated for each data transfer byte. The SSPxIF bit must be cleared by software
and the SSPxSTAT register is used to determine the status of the byte. The SSPxIF bit is set on the
falling edge of the ninth clock pulse.
27.5.3.1 Slave Mode Bus Collision
A slave receives a read request and begins shifting data out on the SDA line. If a bus collision is detected
and the SBCDE bit is set, the BCLxIF bit of the PIRx register is set. Once a bus collision is detected, the
slave goes idle and waits to be addressed again. User software can use the BCLxIF bit to handle a slave
bus collision.
27.5.3.2 7-bit Transmission
A master device can transmit a read request to a slave, and then clock data out of the slave. The list
below outlines what software for a slave will need to do to accomplish a standard transmission. Figure
27-18 can be used as a reference to this list.
1. Master sends a Start condition on SDA and SCL.
2. S bit is set; SSPxIF is set if interrupt on Start detect is enabled.
3. Matching address with R/W bit set is received by the Slave setting SSPxIF bit.
4. Slave hardware generates an ACK and sets SSPxIF.
5. SSPxIF bit is cleared by user.
6. Software reads the received address from SSPxBUF, clearing BF.
7. R/W is set so CKP was automatically cleared after the ACK.
8. The slave software loads the transmit data into SSPxBUF.
9. CKP bit is set releasing SCL, allowing the master to clock the data out of the slave.
10. SSPxIF is set after the ACK response from the master is loaded into the ACKSTAT register.
11. SSPxIF bit is cleared.
12. The slave software checks the ACKSTAT bit to see if the master wants to clock out more data.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 494
Important: 
1. If the master ACKs then the clock will be stretched.
2. ACKSTAT is the only bit updated on the rising edge of the ninth SCL clock
instead of the falling edge.
13. Steps 9-13 are repeated for each transmitted byte.
14. If the master sends a not ACK; the clock is not held, but SSPxIF is still set.
15. The master sends a Restart condition or a Stop.
16. The slave is no longer addressed.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 495
Figure 27-18. I2C Slave, 7-bit Address, Transmission (AHEN = 0)rotatethispage90
Receiving Address Automatic Transmitting Data Automatic Transmitting Data
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
SDA
SCL
SSPxIF
BF
CKP
ACKSTAT
R/W
D/A
S
P
Received address
When R/W is set
R/W is copied from the
Indicates an address
is read from SSPxBUF
SCL is always
held low after 9th SCL
falling edge
matching address byte
has been received
Masters not ACK
is copied to
ACKSTAT
CKP is not
held for not
ACK
BF is automatically
cleared after 8th falling
edge of SCL
Data to transmit is
loaded into SSPxBUF
Set by software
Cleared by software
ACK
ACK
ACK
R/W = 1
SP
Master sends
Stop condition
Rev. 30-000028A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 496
27.5.3.3 7-bit Transmission with Address Hold Enabled
Setting the AHEN bit enables additional clock stretching and interrupt generation after the eighth falling
edge of a received matching address. Once a matching address has been clocked in, CKP is cleared and
the SSPxIF interrupt is set.
Figure 27-19 displays a standard waveform of a 7-bit address slave transmission with AHEN enabled.
1. Bus starts Idle.
2. Master sends Start condition; the S bit is set; SSPxIF is set if interrupt on Start detect is enabled.
3. Master sends matching address with R/W bit set. After the eighth falling edge of the SCL line the
CKP bit is cleared and SSPxIF interrupt is generated.
4. Slave software clears SSPxIF.
5. Slave software reads the ACKTIM, R/W and D/A bits to determine the source of the interrupt.
6. Slave reads the address value from the SSPxBUF register clearing the BF bit.
7. Slave software decides from this information if it wishes to ACK or not ACK and sets the ACKDT bit
accordingly.
8. Slave sets the CKP bit releasing SCL.
9. Master clocks in the ACK value from the slave.
10. Slave hardware automatically clears the CKP bit and sets SSPxIF after the ACK if the R/W bit is
set.
11. Slave software clears SSPxIF.
12. Slave loads value to transmit to the master into SSPxBUF setting the BF bit.
Important:  SSPxBUF cannot be loaded until after the ACK.
13. Slave sets the CKP bit releasing the clock.
14. Master clocks out the data from the slave and sends an ACK value on the ninth SCL pulse.
15. Slave hardware copies the ACK value into the ACKSTAT bit.
16. Steps 10-15 are repeated for each byte transmitted to the master from the slave.
17. If the master sends a not ACK the slave releases the bus allowing the master to send a Stop and
end the communication.
Important:  Master must send a not ACK on the last byte to ensure that the slave
releases the SCL line to receive a Stop.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 497
Figure 27-19. I2C Slave, 7-bit Address, Transmission (AHEN = 1)rotatethispage90
Receiving Address Automatic Transmitting Data Automatic Transmitting Data
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
SDA
SCL
SSPxIF
BF
ACKDT
ACKSTAT
CKP
R/W
D/A
Received address
is read from SSPxBUF
BF is automatically
cleared after 8th falling
edge of SCL
Data to transmit is
loaded into SSPxBUF
Cleared by software
Slave clears
ACKDT to ACK
address
Master’s ACK
response is copied
to SSPxSTAT
CKP not cleared
after not ACK
Set by software,
releases SCL
ACKTIM is cleared
on 9th rising edge of SCL
ACKTIM is set on 8th falling
edge of SCL
When AHEN = 1;
CKP is cleared by hardware
after receiving matching
address.
When R/W = 1;
CKP is always
cleared after ACK
SP
Master sends
Stop condition
ACK
R/W = 1
Master releases SDA
to slave for ACK sequence
ACK
ACK
ACKTIM
Rev. 30-00029A
4/10/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 498
27.5.4 Slave Mode 10-bit Address Reception
This section describes a standard sequence of events for the MSSP module configured as an I2C slave in
10-bit Addressing mode.
Figure 27-20 is used as a visual reference for this description.
This is a step-by-step process of what must be done by the slave software to accomplish I2C
communication.
1. Bus starts Idle.
2. Master sends Start condition; S bit is set; SSPxIF is set if interrupt on Start detect is enabled.
3. Master sends matching high address with R/W bit clear; UA bit is set.
4. Slave sends ACK and SSPxIF is set.
5. Software clears the SSPxIF bit.
6. Software reads received address from SSPxBUF clearing the BF flag.
7. Slave loads low address into SSPxADD, releasing SCL.
8. Master sends matching low address byte to the slave; UA bit is set.
Important:  Updates to the SSPxADD register are not allowed until after the ACK
sequence.
9. Slave sends ACK and SSPxIF is set.
Important:  If the low address does not match, SSPxIF and UA are still set so that the
slave software can set SSPxADD back to the high address. BF is not set because there is
no match. CKP is unaffected.
10. Slave clears SSPxIF.
11. Slave reads the received matching address from SSPxBUF clearing BF.
12. Slave loads high address into SSPxADD.
13. Master clocks a data byte to the slave and clocks out the slaves ACK on the ninth SCL pulse;
SSPxIF is set.
14. If SEN bit is set, CKP is cleared by hardware and the clock is stretched.
15. Slave clears SSPxIF.
16. Slave reads the received byte from SSPxBUF clearing BF.
17. If SEN is set the slave sets CKP to release the SCL.
18. Steps 13-17 repeat for each received byte.
19. Master sends Stop to end the transmission.
27.5.5 10-bit Addressing with Address or Data Hold
Reception using 10-bit addressing with AHEN or DHEN set is the same as with 7-bit modes. The only
difference is the need to update the SSPxADD register using the UA bit. All functionality, specifically when
the CKP bit is cleared and SCL line is held low are the same. Figure 27-21 can be used as a reference of
a slave in 10-bit addressing with AHEN set.
Figure 27-22 shows a standard waveform for a slave transmitter in 10-bit Addressing mode.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 499
Figure 27-20. I2C Slave, 10-bit Address, Reception (SEN = 1, AHEN = 0, DHEN = 0)rotatethispage90
S
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Rev. 30-000030A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 500
Figure 27-21. I2C Slave, 10-bit Address, Reception (SEN = 0, AHEN = 1, DHEN = 0)rotatethispage90
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Rev. 30-000031A
4/3/2017
is read from
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 501
Figure 27-22. I2C Slave, 10-bit Address, Transmission (SEN = 0, AHEN = 0, DHEN = 0)rotatethispage90
Receiving Address
ACK
Receiving Second Address Byte
Sr
Receive First Address Byte
ACK
Transmitting Data Byte
1 1 1 1 0
A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
1 1 1 1 0
A9 A8 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
SSPxIF
BF
UA
CKP
R/W
D/A
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
ACK =1
P
Master sends
Stop condition
Master sends
not ACK
Master sends
Restart event
ACK
R/W = 0
S
Cleared by software
After SSPxADD is
updated, UA is cleared
and SCL is released
High address is loaded
Received address is Data to transmit is
Set by software
Indicates an address
When R/W = 1;
R/W is copied from the
Set by hardware
UA indicates SSPxADD
SSPxBUF loaded
with received address
must be updated
has been received
loaded into SSPxBUF
releases SCL
Masters not ACK
is copied
matching address byte
CKP is cleared on
9th falling edge of SCL
read from SSPxBUF
back into SSPxADD
ACKSTAT
Set by hardware
Rev. 30-000032A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 502
27.5.6 Clock Stretching
Clock stretching occurs when a device on the bus holds the SCL line low, effectively pausing
communication. The slave may stretch the clock to allow more time to handle data or prepare a response
for the master device. A master device is not concerned with stretching as anytime it is active on the bus
and not transferring data it is stretching. Any stretching done by a slave is invisible to the master software
and handled by the hardware that generates SCL.
The CKP bit is used to control stretching in software. Any time the CKP bit is cleared, the module will wait
for the SCL line to go low and then hold it. Setting CKP will release SCL and allow more communication.
27.5.6.1 Normal Clock Stretching
Following an ACK if the R/W bit is set, a read request, the slave hardware will clear CKP. This allows the
slave time to update SSPxBUF with data to transfer to the master. If the SEN bit is set, the slave
hardware will always stretch the clock after the ACK sequence. Once the slave is ready; CKP is set by
software and communication resumes.
Important: 
1. The BF bit has no effect on whether or not the clock will be stretched. This is different
than previous versions of the module that would not stretch the clock, clear CKP, if
SSPxBUF was read before the ninth falling edge of SCL.
2. Previous versions of the module did not stretch the clock for a transmission if SSPxBUF
was loaded before the ninth falling edge of SCL. It is now always cleared for read
requests.
27.5.6.2 10-bit Addressing Mode
In 10-bit Addressing mode, when the UA bit is set, the clock is always stretched. This is the only time the
SCL is stretched without CKP being cleared. SCL is released immediately after a write to SSPxADD.
Important:  Previous versions of the module did not stretch the clock if the second address
byte did not match.
27.5.6.3 Byte NACKing
When the AHEN bit is set, CKP is cleared by hardware after the eighth falling edge of SCL for a received
matching address byte. When the DHEN bit is set, CKP is cleared after the eighth falling edge of SCL for
received data.
Stretching after the eighth falling edge of SCL allows the slave to look at the received address or data
and decide if it wants to ACK the received data.
27.5.7 Clock Synchronization and the CKP bit
Any time the CKP bit is cleared, the module will wait for the SCL line to go low and then hold it. However,
clearing the CKP bit will not assert the SCL output low until the SCL output is already sampled low.
Therefore, the CKP bit will not assert the SCL line until an external I2C master device has already
asserted the SCL line. The SCL output will remain low until the CKP bit is set and all other devices on the
I2C bus have released SCL. This ensures that a write to the CKP bit will not violate the minimum high
time requirement for SCL (see the following figure).
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 503
Figure 27-23. Clock Synchronization Timing
SDA
SCL
DX ‚ 1DX
WR
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SSPxCON1
CKP
Master device
releases clock
Master device
asserts clock
Rev. 30-000033A
4/3/2017
27.5.8 General Call Address Support
The addressing procedure for the I2C bus is such that the first byte after the Start condition usually
determines which device will be the slave addressed by the master device. The exception is the general
call address that can address all devices. When this address is used, all devices should, in theory,
respond with an acknowledge.
The general call address is a reserved address in the I2C protocol, defined as address 0x00. When the
GCEN bit is set, the slave module will automatically ACK the reception of this address regardless of the
value stored in SSPxADD. After the slave clocks in an address of all zeros with the R/W bit clear, an
interrupt is generated and slave software can read SSPxBUF and respond. The following figure shows a
general call reception sequence.
Figure 27-24. Slave Mode General Call Address Sequence
SDA
SCL
S
SSPxIF
BF (SSPxSTAT<0>)
Cleared by software
SSPxBUF is read
R/W =0
ACK
General Call Address
Address is compared to General Call Address
Receiving Data ACK
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
D7 D6 D5 D4 D3 D2 D1 D0
after ACK, set interrupt
GCEN (SSPxCON2<7>)
1
Rev. 30-000034A
4/3/2017
In 10-bit Address mode, the UA bit will not be set on the reception of the general call address. The slave
will prepare to receive the second byte as data, just as it would in 7-bit mode.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 504
If the AHEN bit is set, just as with any other address reception, the slave hardware will stretch the clock
after the eighth falling edge of SCL. The slave must then set its ACKEN value and release the clock with
communication progressing as it would normally.
27.5.9 SSP Mask Register
An SSP Mask register (SSPxMSK) is available in I2C Slave mode as a mask for the value held in the
SSPSR register during an address comparison operation. A zero (‘0’) bit in the SSPxMSK register has
the effect of making the corresponding bit of the received address a “don’t care”.
This register is reset to all ‘1’s upon any Reset condition and, therefore, has no effect on standard SSP
operation until written with a mask value.
The SSP Mask register is active during:
7-bit Address mode: address compare of A<7:1>.
10-bit Address mode: address compare of A<7:0> only. The SSP mask has no effect during the
reception of the first (high) byte of the address.
27.6 I2C Master Mode
Master mode is enabled by setting and clearing the appropriate SSPM bits and setting the SSPEN bit. In
Master mode, the SDA and SCK pins must be configured as inputs. The MSSP peripheral hardware will
override the output driver TRIS controls when necessary to drive the pins low.
Master mode of operation is supported by interrupt generation on the detection of the Start and Stop
conditions. The Stop (P) and Start (S) bits are cleared from a Reset or when the MSSP module is
disabled. Control of the I2C bus may be taken when the P bit is set, or the bus is Idle.
In Firmware Controlled Master mode, user code conducts all I2C bus operations based on Start and Stop
bit condition detection. Start and Stop condition detection is the only active circuitry in this mode. All other
communication is done by the user software directly manipulating the SDA and SCL lines.
The following events will cause the SSP Interrupt Flag bit, SSPxIF, to be set (SSP interrupt, if enabled):
Start condition detected
Stop condition detected
Data transfer byte transmitted/received
Acknowledge transmitted/received
Repeated Start generated
Important: 
1. The MSSP module, when configured in I2C Master mode, does not allow queuing of
events. For instance, the user is not allowed to initiate a Start condition and immediately
write the SSPxBUF register to initiate transmission before the Start condition is complete.
In this case, the SSPxBUF will not be written to and the WCOL bit will be set, indicating
that a write to the SSPxBUF did not occur.
2. Master mode suspends Start/Stop detection when sending the Start/Stop condition by
means of the SEN/PEN control bits. The SSPxIF bit is set at the end of the Start/Stop
generation when hardware clears the control bit.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 505
27.6.1 I2C Master Mode Operation
The master device generates all of the serial clock pulses and the Start and Stop conditions. A transfer is
ended with a Stop condition or with a Repeated Start condition. Since the Repeated Start condition is
also the beginning of the next serial transfer, the I2C bus will not be released.
In Master Transmitter mode, serial data is output through SDA, while SCL outputs the serial clock. The
first byte transmitted contains the slave address of the receiving device (7 bits) and the R/W bit. In this
case, the R/W bit will be logic ‘0’. Serial data is transmitted eight bits at a time. After each byte is
transmitted, an Acknowledge bit is received. Start and Stop conditions are output to indicate the
beginning and the end of a serial transfer.
In Master Receive mode, the first byte transmitted contains the slave address of the transmitting device
(7 bits) and the R/W bit. In this case, the R/W bit will be logic ‘1’. Thus, the first byte transmitted is a 7-bit
slave address followed by a ‘1’ to indicate the receive bit. Serial data is received via SDA, while SCL
outputs the serial clock. Serial data is received eight bits at a time. After each byte is received, an
Acknowledge bit is transmitted. Start and Stop conditions indicate the beginning and end of transmission.
A Baud Rate Generator is used to set the clock frequency output on SCL. See 27.7 Baud Rate
Generator for more detail.
27.6.2 Clock Arbitration
Clock arbitration occurs when the master, during any receive, transmit or Repeated Start/Stop condition,
releases the SCL pin (SCL allowed to float high). When the SCL pin is allowed to float high, the Baud
Rate Generator (BRG) is suspended from counting until the SCL pin is actually sampled high. When the
SCL pin is sampled high, the Baud Rate Generator is reloaded with the contents of 27.9.6 SSPxADD
and begins counting. This ensures that the SCL high time will always be at least one BRG rollover count
in the event that the clock is held low by an external device as shown in the following figure.
Figure 27-25. Baud Rate Generator Timing with Clock Arbitration
SDA
SCL
SCL deasserted but slave holds
DX ‚ 1DX
BRG
SCL is sampled high, reload takes
place and BRG starts its count
03h 02h 01h 00h (hold off) 03h 02h
Reload
BRG
Value
SCL low (clock arbitration)
SCL allowed to transition high
BRG decrements on
Q2 and Q4 cycles
Rev. 30-000035A
4/3/2017
27.6.3 WCOL Status Flag
If the user writes the SSPxBUF when a Start, Restart, Stop, Receive or Transmit sequence is in progress,
the WCOL bit is set and the contents of the buffer are unchanged (the write does not occur). Any time the
WCOL bit is set it indicates that an action on SSPxBUF was attempted while the module was not idle.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 506
Important:  Because queuing of events is not allowed, writing to the lower five bits of
SSPxCON2 is disabled until the Start condition is complete.
27.6.4 I2C Master Mode Start Condition Timing
To initiate a Start condition (Figure 27-26), the user sets the SEN Start Enable bit. If the SDA and SCL
pins are sampled high, the Baud Rate Generator is reloaded with the contents of SSPxADD and starts its
count. If SCL and SDA are both sampled high when the Baud Rate Generator times out (TBRG), the SDA
pin is driven low. The action of the SDA being driven low while SCL is high is the Start condition and
causes the S bit to be set. Following this, the Baud Rate Generator is reloaded with the contents of
SSPxADD and resumes its count. When the Baud Rate Generator times out (TBRG), the SEN bit will be
automatically cleared by hardware; the Baud Rate Generator is suspended, leaving the SDA line held low
and the Start condition is complete.
Important: 
1. If at the beginning of the Start condition, the SDA and SCL pins are already sampled low,
or if during the Start condition, the SCL line is sampled low before the SDA line is driven
low, a bus collision occurs, the Bus Collision Interrupt Flag, BCLxIF, is set, the Start
condition is aborted and the I2C module is reset into its Idle state.
2. The Philips I2C specification states that a bus collision cannot occur on a Start.
Figure 27-26. First Start Bit Timing
SDA
SCL
S
TBRG
1st bit 2nd bit
TBRG
SDA = 1, At completion of Start bit,
SCL = 1
Write to SSPxBUF occurs here
TBRG
hardware clears SEN bit
TBRG
Write to SEN bit occurs here Set S bit (SSPxSTAT<3>)
a nd set s SSPx I F bi t
Rev. 30-000036A
4/3/2017
27.6.5 I2C Master Mode Repeated Start Condition Timing
A Repeated Start condition (Figure 27-27) occurs when the RSEN bit is programmed high and the master
state machine is no longer active. When the RSEN bit is set, the SCL pin is asserted low. When the SCL
pin is sampled low, the Baud Rate Generator is loaded and begins counting. The SDA pin is released
(brought high) for one Baud Rate Generator count (TBRG). When the Baud Rate Generator times out, if
SDA is sampled high, the SCL pin will be deasserted (brought high). When SCL is sampled high, the
Baud Rate Generator is reloaded and begins counting. SDA and SCL must be sampled high for one
TBRG. This action is then followed by assertion of the SDA pin (SDA = 0) for one TBRG while SCL is high.
SCL is asserted low. Following this, the RSEN bit will be automatically cleared and the Baud Rate
Generator will not be reloaded, leaving the SDA pin held low. As soon as a Start condition is detected on
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 507
the SDA and SCL pins, the S bit will be set. The SSPxIF bit will not be set until the Baud Rate Generator
has timed out.
Important: 
1. If RSEN is programmed while any other event is in progress, it will not take effect.
2. A bus collision during the Repeated Start condition occurs if:
SDA is sampled low when SCL goes from low-to-high.
SCL goes low before SDA is asserted low. This may indicate that another master is
attempting to transmit a data ‘1’.
Figure 27-27. Repeated Start Condition Waveform
SDA
SCL
Repeated Start
Write to SSPxCON2
Write to SSPxBUF occurs here
At completion of Start bit,
hardware clears the RSEN bit
1st bit
S bit set by hardware
TBRG
TBRG
SDA = 1, SDA = 1,
SCL (no change) SCL = 1
occurs here
TBRG TBRG TBRG
and sets SSPxIF
Sr
Rev. 30-000037A
4/10/2017
27.6.6 I2C Master Mode Transmission
Transmission of a data byte, a 7-bit address or the other half of a 10-bit address is accomplished by
simply writing a value to the SSPxBUF register. This action will set the Buffer Full flag bit, BF, and allow
the Baud Rate Generator to begin counting and start the next transmission. Each bit of address/data will
be shifted out onto the SDA pin after the falling edge of SCL is asserted. SCL is held low for one Baud
Rate Generator rollover count (TBRG). Data should be valid before SCL is released high. When the SCL
pin is released high, it is held that way for TBRG. The data on the SDA pin must remain stable for that
duration and some hold time after the next falling edge of SCL. After the eighth bit is shifted out (the
falling edge of the eighth clock), the BF flag is cleared and the master releases SDA. This allows the
slave device being addressed to respond with an ACK bit during the ninth bit time if an address match
occurred, or if data was received properly. The status of ACK is written into the ACKSTAT bit on the rising
edge of the ninth clock. If the master receives an Acknowledge, the Acknowledge Status bit, ACKSTAT, is
cleared. If not, the bit is set. After the ninth clock, the SSPxIF bit is set and the master clock (Baud Rate
Generator) is suspended until the next data byte is loaded into the SSPxBUF, leaving SCL low and SDA
unchanged (Figure 27-28).
After the write to the SSPxBUF, each bit of the address will be shifted out on the falling edge of SCL until
all seven address bits and the R/W bit are completed. On the falling edge of the eighth clock, the master
will release the SDA pin, allowing the slave to respond with an Acknowledge. On the falling edge of the
ninth clock, the master will sample the SDA pin to see if the address was recognized by a slave. The
status of the ACK bit is loaded into the ACKSTAT Status bit of the SSPxCON2 register. Following the
falling edge of the ninth clock transmission of the address, the SSPxIF is set, the BF flag is cleared and
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 508
the Baud Rate Generator is turned off until another write to the SSPxBUF takes place, holding SCL low
and allowing SDA to float.
27.6.6.1 BF Status Flag
In Transmit mode, the BF bit is set when the CPU writes to SSPxBUF and is cleared when all eight bits
are shifted out.
27.6.6.2 WCOL Status Flag
If the user writes the SSPxBUF when a transmit is already in progress (i.e., SSPSR is still shifting out a
data byte), the WCOL bit is set and the contents of the buffer are unchanged (the write does not occur).
The WCOL bit must be cleared by software before the next transmission.
27.6.6.3 ACKSTAT Status Flag
In Transmit mode, the ACKSTAT bit is cleared when the slave has sent an Acknowledge (ACK = 0) and is
set when the slave does not Acknowledge (ACK = 1). A slave sends an Acknowledge when it has
recognized its address (including a general call), or when the slave has properly received its data.
27.6.6.4 Typical transmit sequence:
1. The user generates a Start condition by setting the SEN bit.
2. SSPxIF is set by hardware on completion of the Start.
3. SSPxIF is cleared by software.
4. The MSSP module will wait the required start time before any other operation takes place.
5. The user loads the SSPxBUF with the slave address to transmit.
6. Address is shifted out the SDA pin until all eight bits are transmitted. Transmission begins as soon
as SSPxBUF is written to.
7. The MSSP module shifts in the ACK bit from the slave device and writes its value into the
ACKSTAT bit.
8. The MSSP module generates an interrupt at the end of the ninth clock cycle by setting the SSPxIF
bit.
9. The user loads the SSPxBUF with eight bits of data.
10. Data is shifted out the SDA pin until all eight bits are transmitted.
11. The MSSP module shifts in the ACK bit from the slave device and writes its value into the
ACKSTAT bit.
12. Steps 8-11 are repeated for all transmitted data bytes.
13. The user generates a Stop or Restart condition by setting the PEN or RSEN bits. Interrupt is
generated once the Stop/Restart condition is complete.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 509
Figure 27-28. I2C Master Mode Waveform (Transmission, 7 or 10-bit Address)
SDA
SCL
SSPxIF
BF (SSPxSTAT<0>)
SEN
A7 A6 A5 A4 A3 A2 A1 ACK =0D7 D6 D5 D4 D3 D2 D1 D0
ACK
Transmitting Data or Second Half
R/W = 0
Transmit Address to Slave
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 P
Cleared by software service routine
SSPxBUF is written by software
from SSP interrupt
After Start condition, SEN cleared by hardware
S
SSPxBUF written with 7-bit address and R/W
start transmit
SCL held low
while CPU
responds to SSPxIF
SEN = 0
of 10-bit Address
Write SSPxCON2<0> SEN = 1
Start condition begins From slave, clear ACKSTAT bit SSPxCON2<6>
ACKSTAT in
SSPxCON2 = 1
Cleared by software
SSPxBUF written
PEN
R/W
Cleared by software
Rev. 30-000038A
4/3/2017
27.6.7 I2C Master Mode Reception
Master mode reception (Figure 27-29) is enabled by programming the RCEN Receive Enable bit.
Important:  The MSSP module must be in an Idle state before the RCEN bit is set or the
RCEN bit will be disregarded.
The Baud Rate Generator begins counting and on each rollover, the state of the SCL pin changes (high-
to-low/low-to-high) and data is shifted into the SSPSR. After the falling edge of the eighth clock all the
following events occur:
The receive enable flag is automatically cleared
The contents of the SSPSR are loaded into the SSPxBUF
The BF flag bit is set
The SSPxIF flag bit is set
The Baud Rate Generator is suspended from counting
The SCL pin is held low
The MSSP is now in Idle state awaiting the next command. When the buffer is read by the CPU, the BF
flag bit is automatically cleared. The user can then send an Acknowledge bit at the end of reception by
setting the Acknowledge Sequence Enable, ACKEN bit.
27.6.7.1 BF Status Flag
In receive operation, the BF bit is set when an address or data byte is loaded into SSPxBUF from
SSPSR. It is cleared when the SSPxBUF register is read.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 510
27.6.7.2 SSPOV Status Flag
In receive operation, the SSPOV bit is set when eight bits are received into the SSPSR while the BF flag
bit is already set from a previous reception.
27.6.7.3 WCOL Status Flag
If the user writes the SSPxBUF when a receive is already in progress (i.e., SSPSR is still shifting in a data
byte), the WCOL bit is set and the contents of the buffer are unchanged (the write does not occur).
27.6.7.4 Typical Receive Sequence:
1. The user generates a Start condition by setting the SEN bit.
2. SSPxIF is set by hardware on completion of the Start.
3. SSPxIF is cleared by software.
4. User writes SSPxBUF with the slave address to transmit and the R/W bit set.
5. Address is shifted out the SDA pin until all eight bits are transmitted. Transmission begins as soon
as SSPxBUF is written to.
6. The MSSP module shifts in the ACK bit from the slave device and writes its value into the
ACKSTAT bit.
7. The MSSP module generates an interrupt at the end of the ninth clock cycle by setting the SSPxIF
bit.
8. User sets the RCEN bit and the master clocks in a byte from the slave.
9. After the eighth falling edge of SCL, SSPxIF and BF are set.
10. Master clears SSPxIF and reads the received byte from SSPUF which clears BF.
11. Master sets the ACK value to be sent to slave in the ACKDT bit and initiates the ACK by setting the
ACKEN bit.
12. Master’s ACK is clocked out to the slave and SSPxIF is set.
13. User clears SSPxIF.
14. Steps 8-13 are repeated for each received byte from the slave.
15. Master sends a not ACK or Stop to end communication.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 511
Figure 27-29. I2C Master Mode Waveform (Reception, 7-bit Address)rotatethispage90
P
9
87
6
5
D0
D1
D2
D3D4
D5
D6D7
S
A7 A6 A5 A4 A3 A2 A1
SDA
SCL 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4
Bus master
terminates
transfer
ACK
Receiving Data from Slave
Receiving Data from Slave
D0
D1
D2
D3D4
D5
D6D7
ACK
R/W
Transmit Address to Slave
SSPxIF
BF
ACK is not sent
Write to SSPxCON2<0>(SEN = 1),
Write to SSPxBUF occurs here, ACK from Slave
Master configured as a receiver
by programming SSPxCON2<3> (RCEN = 1)
PEN bit = 1
written here
Data shifted in on falling edge of CLK
Cleared by software
start XMIT
SEN = 0
SSPOV
SDA = 0, SCL = 1
while CPU
(SSPxSTAT<0>)
ACK
Cleared by software
Cleared by software
Set SSPxIF interrupt
at end of receive
Set P bit
(SSPxSTAT<4>)
and SSPxIF
Cleared in
software
ACK from Master
Set SSPxIF at end
Set SSPxIF interrupt
at end of Acknowledge
sequence
Set SSPxIF interrupt
at end of Acknow-
ledge sequence
of receive
Set ACKEN, start Acknowledge sequence
SSPOV is set because
SSPxBUF is still full
SDA = ACKDT = 1
RCEN cleared
automatically
RCEN = 1, start
next receive
Write to SSPxCON2<4>
to start Acknowledge sequence
SDA = ACKDT (SSPxCON2<5>) = 0
RCEN cleared
automatically
responds to SSPxIF
ACKEN
begin Start condition
Cleared by software
SDA = ACKDT = 0
Last bit is shifted into SSPSR and
contents are unloaded into SSPxBUF
RCEN
Master configured as a receiver
by programming SSPxCON2<3> (RCEN = 1)
RCEN cleared
automatically
ACK from Master
SDA = ACKDT = 0RCEN cleared
automatically
Rev. 30-000039A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 512
27.6.8 Acknowledge Sequence Timing
An Acknowledge sequence is enabled by setting the Acknowledge Sequence Enable ACKEN bit. When
this bit is set, the SCL pin is pulled low and the contents of the Acknowledge data bit are presented on
the SDA pin. If the user wishes to generate an Acknowledge, then the ACKDT bit should be cleared. If
not, the user should set the ACKDT bit before starting an Acknowledge sequence. The Baud Rate
Generator then counts for one rollover period (TBRG) and the SCL pin is deasserted (pulled high). When
the SCL pin is sampled high (clock arbitration), the Baud Rate Generator counts for TBRG. The SCL pin is
then pulled low. Following this, the ACKEN bit is automatically cleared, the Baud Rate Generator is
turned off and the MSSP module then goes into Idle mode.
Figure 27-30. Acknowledge Sequence Waveform
Note: TBRG = one Baud Rate Generator period.
SDA
SCL
SSPxIF set at
Acknowledge sequence starts here,
write to SSPxCON2 ACKEN automatically cleared
Cleared in
TBRG TBRG
the end of receive
8
ACKEN = 1, ACKDT = 0
D0
9
SSPxIF
software SSPxIF set at the end
of Acknowledge sequence
Cleared in
software
ACK
Rev. 30-000040A
4/3/2017
27.6.8.1 Acknowledge Write Collision
If the user writes the SSPxBUF when an Acknowledge sequence is in progress, then the WCOL bit is set
and the contents of the buffer are unchanged (the write does not occur).
27.6.9 Stop Condition Timing
A Stop bit is asserted on the SDA pin at the end of a receive/transmit by setting the Stop Sequence
Enable PEN bit. At the end of a receive/transmit, the SCL line is held low after the falling edge of the ninth
clock. When the PEN bit is set, the master will assert the SDA line low. When the SDA line is sampled
low, the Baud Rate Generator is reloaded and counts down to ‘0’. When the Baud Rate Generator times
out, the SCL pin will be brought high and one TBRG (Baud Rate Generator rollover count) later, the SDA
pin will be deasserted. When the SDA pin is sampled high while SCL is high, the P bit is set. One TBRG
later, the PEN bit is cleared and the SSPxIF bit is set.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 513
Figure 27-31. Stop Condition in Receive or Transmit Mode
SCL
SDA
SDA asserted low before rising edge of clock
Write to SSPxCON2,
set PEN
Falling edge of
SCL = 1for TBRG, followed by SDA = 1for TBRG
9th clock
SCL brought high after TBRG
Note: TBRG = one Baud Rate Generator period.
TBRG TBRG
after SDA sampled high. P bit (SSPxSTAT<4>) is set.
TBRG
to setup Stop condition
ACK
P
TBRG
PEN bit (SSPxCON2<2>) is cleared by
hardware and the SSPxIF bit is set
Rev. 30-000041A
4/3/2017
27.6.9.1 Write Collision on Stop
If the user writes the SSPxBUF when a Stop sequence is in progress, then the WCOL bit is set and the
contents of the buffer are unchanged (the write does not occur).
27.6.10 Sleep Operation
While in Sleep mode, the I2C slave module can receive addresses or data and when an address match or
complete byte transfer occurs, wake the processor from Sleep (if the MSSP interrupt is enabled).
27.6.11 Effects of a Reset
A Reset disables the MSSP module and terminates the current transfer.
27.6.12 Multi-Master Mode
In Multi-Master mode, the interrupt generation on the detection of the Start and Stop conditions allows the
determination of when the bus is free. The Stop (P) and Start (S) bits are cleared from a Reset or when
the MSSP module is disabled. Control of the I2C bus may be taken when the P bit is set, or the bus is
Idle, with both the S and P bits clear. When the bus is busy, enabling the SSP interrupt will generate the
interrupt when the Stop condition occurs.
In multi-master operation, the SDA line must be monitored for arbitration to see if the signal level is the
expected output level. This check is performed by hardware with the result placed in the BCLxIF bit.
The states where arbitration can be lost are:
Address Transfer
Data Transfer
A Start Condition
A Repeated Start Condition
An Acknowledge Condition
27.6.13 Multi-Master Communication, Bus Collision and Bus Arbitration
Multi-Master mode support is achieved by bus arbitration. When the master outputs address/data bits
onto the SDA pin, arbitration takes place when the master outputs a ‘1’ on SDA, by letting SDA float high
and another master asserts a ‘0’. When the SCL pin floats high, data should be stable. If the expected
data on SDA is a ‘1’ and the data sampled on the SDA pin is ‘0’, then a bus collision has taken place. The
master will set the Bus Collision Interrupt Flag, BCLxIF and reset the I2C port to its Idle state (Figure
27-32).
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 514
If a transmit was in progress when the bus collision occurred, the transmission is halted, the BF flag is
cleared, the SDA and SCL lines are deasserted and the SSPxBUF can be written to. When the user
services the bus collision Interrupt Service Routine and if the I2C bus is free, the user can resume
communication by asserting a Start condition.
If a Start, Repeated Start, Stop or Acknowledge condition was in progress when the bus collision
occurred, the condition is aborted, the SDA and SCL lines are deasserted and the respective control bits
in the SSPxCON2 register are cleared. When the user services the bus collision Interrupt Service Routine
and if the I2C bus is free, the user can resume communication by asserting a Start condition.
The master will continue to monitor the SDA and SCL pins. If a Stop condition occurs, the SSPxIF bit will
be set.
A write to the SSPxBUF will start the transmission of data at the first data bit, regardless of where the
transmitter left off when the bus collision occurred.
In Multi-Master mode, the interrupt generation on the detection of Start and Stop conditions allows the
determination of when the bus is free. Control of the I2C bus can be taken when the P bit is set, or the
bus is Idle and the S and P bits are cleared.
Figure 27-32. Bus Collision Timing for Transmit and Acknowledge
SDA
SCL
BCLxIF
SDA released
SDA line pulled low
by another source
Sample SDA. While SCL is high,
data does not match what is driven
Bus collision has occurred.
Set bus collision
interrupt (BCLxIF)
by the master.
by master
Data changes
while SCL = 0
Rev. 30-000042A
4/3/2017
27.6.13.1 Bus Collision During a Start Condition
During a Start condition, a bus collision occurs if:
1. SDA or SCL are sampled low at the beginning of the Start condition (Figure 27-33).
2. SCL is sampled low before SDA is asserted low (Figure 27-34).
During a Start condition, both the SDA and the SCL pins are monitored.
If the SDA pin is already low, or the SCL pin is already low, then all of the following occur:
the Start condition is aborted,
the BCLxIF flag is set and
the MSSP module is reset to its Idle state (Figure 27-33).
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 515
Figure 27-33. Bus Collision During Start Condition (SDA Only)
SDA
SCL
SEN
SDA sampled low before
SDA goes low before the SEN bit is set.
S bit and SSPxIF set because
SSPx module reset into Idle state.
SEN cleared automatically because of bus collision.
S bit and SSPxIF set because
Set SEN, enable Start
condition if SDA = 1, SCL = 1
SDA = 0, SCL = 1.
BCLxIF
S
SSPxIF
SDA = 0, SCL = 1.
SSPxIF and BCLxIF are
cleared by software
SSPxIF and BCLxIF are
cleared by software
Set BCLxIF,
Start condition. Set BCLxIF.
Rev. 30-000043A
4/3/2017
The Start condition begins with the SDA and SCL pins deasserted. When the SDA pin is sampled high,
the Baud Rate Generator is loaded and counts down. If the SCL pin is sampled low while SDA is high, a
bus collision occurs because it is assumed that another master is attempting to drive a data ‘1’ during the
Start condition.
Figure 27-34. Bus Collision During Start Condition (SCL = 0)
SDA
SCL
SEN bus collision occurs. Set BCLxIF.
SCL = 0before SDA = 0,
Set SEN, enable Start
sequence if SDA = 1, SCL = 1
TBRG TBRG
SDA = 0, SCL = 1
BCLxIF
S
SSPxIF
Interrupt cleared
by software
bus collision occurs. Set BCLxIF.
SCL = 0before BRG time-out,
0 0
00
Rev. 30-000044A
4/3/2017
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 516
If the SDA pin is sampled low during this count, the BRG is reset and the SDA line is asserted early
(Figure 27-35). If, however, a ‘1’ is sampled on the SDA pin, the SDA pin is asserted low at the end of the
BRG count. The Baud Rate Generator is then reloaded and counts down to zero; if the SCL pin is
sampled as ‘0’ during this time, a bus collision does not occur. At the end of the BRG count, the SCL pin
is asserted low.
Figure 27-35. BRG Reset Due to SDA Arbitration During Start Condition
SDA
SCL
SEN
Set S
Less than TBRG TBRG
SDA = 0, SCL = 1
BCLxIF
S
SSPxIF
S
Interrupts cleared
by software
set SSPxIF
SDA = 0, SCL = 1,
SCL pulled low after BRG
time out
Set SSPxIF
0
SDA pulled low by other master.
Reset BRG and assert SDA.
Set SEN, enable Start
sequence if SDA = 1, SCL = 1
Rev. 30-000045A
4/10/2017
-
Important:  The reason that bus collision is not a factor during a Start condition is that no two
bus masters can assert a Start condition at the exact same time. Therefore, one master will
always assert SDA before the other. This condition does not cause a bus collision because the
two masters must be allowed to arbitrate the first address following the Start condition. If the
address is the same, arbitration must be allowed to continue into the data portion, Repeated
Start or Stop conditions.
27.6.13.2 Bus Collision During a Repeated Start Condition
During a Repeated Start condition, a bus collision occurs if:
1. A low level is sampled on SDA when SCL goes from low level to high level (Case 1).
2. SCL goes low before SDA is asserted low, indicating that another master is attempting to transmit a
data ‘1’ (Case 2).
When the user releases SDA and the pin is allowed to float high, the BRG is loaded with SSPxADD and
counts down to zero. The SCL pin is then deasserted and when sampled high, the SDA pin is sampled.
If SDA is low, a bus collision has occurred (i.e., another master is attempting to transmit a data ‘0’, Figure
27-36). If SDA is sampled high, the BRG is reloaded and begins counting. If SDA goes from high-to-low
before the BRG times out, no bus collision occurs because no two masters can assert SDA at exactly the
same time.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 517
Figure 27-36. Bus Collision During a Repeated Start Condition (Case 1)
SDA
SCL
RSEN
BCLxIF
S
SSPxIF
Sample SDA when SCL goes high.
If SDA = 0, set BCLxIF and release SDA and SCL.
Cleared by software
0
0
Rev. 30-000046A
4/3/2017
If SCL goes from high-to-low before the BRG times out and SDA has not already been asserted, a bus
collision occurs. In this case, another master is attempting to transmit a data ‘1’ during the Repeated Start
condition, see Figure 27-37.
If, at the end of the BRG time-out, both SCL and SDA are still high, the SDA pin is driven low and the
BRG is reloaded and begins counting. At the end of the count, regardless of the status of the SCL pin, the
SCL pin is driven low and the Repeated Start condition is complete.
Figure 27-37. Bus Collision During Repeated Start Condition (Case 2)
SDA
SCL
BCLxIF
RSEN
S
SSPxIF
Interrupt cleared
by software
SCL goes low before SDA,
set BCLxIF. Release SDA and SCL.
TBRG TBRG
0
Rev. 30-000047A
4/3/2017
27.6.13.3 Bus Collision During a Stop Condition
Bus collision occurs during a Stop condition if:
1. After the SDA pin has been deasserted and allowed to float high, SDA is sampled low after the
BRG has timed out (Case 1).
2. After the SCL pin is deasserted, SCL is sampled low before SDA goes high (Case 2).
The Stop condition begins with SDA asserted low. When SDA is sampled low, the SCL pin is allowed to
float. When the pin is sampled high (clock arbitration), the Baud Rate Generator is loaded with SSPxADD
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 518
and counts down to zero. After the BRG times out, SDA is sampled. If SDA is sampled low, a bus
collision has occurred. This is due to another master attempting to drive a data ‘0’ (Figure 27-38). If the
SCL pin is sampled low before SDA is allowed to float high, a bus collision occurs. This is another case of
another master attempting to drive a data ‘0’ (Figure 27-39).
Figure 27-38. Bus Collision During a Stop Condition (Case 1)
SDA
SCL
BCLxIF
PEN
P
SSPxIF
TBRG TBRG TBRG
SDA asserted low
SDA sampled
low after TBRG,
set BCLxIF
0
0
Rev. 30-000048A
4/3/2017
Figure 27-39. Bus Collision During a Stop Condition (Case 2)
SDA
SCL
BCLxIF
PEN
P
SSPxIF
TBRG TBRG TBRG
Assert SDA SCL goes low before SDA goes high,
set BCLxIF
0
0
Rev. 30-000049A
4/3/2017
27.7 Baud Rate Generator
The MSSP module has a Baud Rate Generator available for clock generation in both I2C and SPI Master
modes. The Baud Rate Generator (BRG) reload value is placed in the SSPxADD register. When a write
occurs to SSPxBUF, the Baud Rate Generator will automatically begin counting down.
Once the given operation is complete, the internal clock will automatically stop counting and the clock pin
will remain in its last state.
An internal signal “Reload” shown in Figure 27-40 triggers the value from SSPxADD to be loaded into the
BRG counter. This occurs twice for each oscillation of the module clock line. The logic dictating when the
reload signal is asserted depends on the mode in which the MSSP is being operated.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 519
Table 27-1 illustrates clock rates based on instruction cycles and the BRG value loaded into SSPxADD.
Example 27-1. MSSP Baud Rate Generator Frequency Equation
 =
4 ×  + 1`
Figure 27-40. Baud Rate Generator Block Diagram
SSPM<3:0>
BRG Down Counter
SSPCLK FOSC/2
SSPxADD<7:0>
SSPM<3:0>
SCL
Reload
Control
Reload
Rev. 30-000050A
4/3/2017
Important:  Values of 0x00, 0x01 and 0x02 are not valid for SSPxADD when used as a Baud
Rate Generator for I2C. This is an implementation limitation.
Table 27-1. MSSP Clock Rate w/BRG
FOSC FCY BRG Value Fclock
(2 Rollovers of BRG)
32 MHz 8 MHz 13h 400 kHz
32 MHz 8 MHz 19h 308 kHz
32 MHz 8 MHz 4Fh 100 kHz
16 MHz 4 MHz 09h 400 kHz
16 MHz 4 MHz 0Ch 308 kHz
16 MHz 4 MHz 27h 100 kHz
4 MHz 1 MHz 09h 100 kHz
Note:  Refer to the I/O port electrical specifications in the "Electrical Specifications" section, Internal
Oscillator Parameters, to ensure the system is designed to support Iol requirements.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 520
27.8 Register Summary: MSSP Control
Address Name Bit Pos.
0x0E8D SSP2BUF 7:0 BUF[7:0]
0x0E8E SSP2ADD 7:0 ADD[7:0]
0x0E8F SSP2MSK 7:0 MSK[6:0] MSK0
0x0E90 SSP2STAT 7:0 SMP CKE D/A P S R/W UA BF
0x0E91 SSP2CON1 7:0 WCOL SSPOV SSPEN CKP SSPM[3:0]
0x0E92 SSP2CON2 7:0 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
0x0E93 SSP2CON3 7:0 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
0x0E94
...
0x0F90
Reserved
0x0F91 SSP1BUF 7:0 BUF[7:0]
0x0F92 SSP1ADD 7:0 ADD[7:0]
0x0F93 SSP1MSK 7:0 MSK[6:0] MSK0
0x0F94 SSP1STAT 7:0 SMP CKE D/A P S R/W UA BF
0x0F95 SSP1CON1 7:0 WCOL SSPOV SSPEN CKP SSPM[3:0]
0x0F96 SSP1CON2 7:0 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
0x0F97 SSP1CON3 7:0 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
27.9 Register Definitions: MSSP Control
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 521
27.9.1 SSPxSTAT
Name:  SSPxSTAT
Address:  0xF94,0xE90
MSSP Status Register
Bit 7 6 5 4 3 2 1 0
SMP CKE D/A P S R/W UA BF
Access R/W R/W RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bit 7 – SMP Slew Rate Control bit
Value Mode Description
1SPI Master Input data is sampled at the end of data output time
0SPI Master Input data is sampled at the middle of data output time
0SPI Slave Keep this bit cleared in SPI Slave mode
1I2C Slew rate control is disabled for Standard Speed mode (100 kHz and 1 MHz)
0I2C Slew rate control is enabled for High-Speed mode (400 kHz)
Bit 6 – CKE
SPI: Clock select bit(4) I2C: SMBus Select bit
Value Mode Description
1SPI Transmit occurs on the transition from active to Idle clock state
0SPI Transmit occurs on the transition from Idle to active clock state
1I2C Enables SMBus-specific inputs
0I2C Disables SMBus-specific inputs
Bit 5 – D/A
Data/Address bit
Value Mode Description
xSPI or I2C Master Reserved
1I2C Slave Indicates that the last byte received or transmitted was data
0I2C Slave Indicates that the last byte received or transmitted was address
Bit 4 – P
Stop bit(1)
Value Mode Description
xSPI Reserved
1I2C Stop bit was detected last
0I2C Stop bit was not detected last
Bit 3 – S
Start bit(1)
Value Mode Description
xSPI Reserved
1I2C Start bit was detected last
0I2C Start bit was not detected last
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
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Bit 2 – R/W
Read/Write Information bit(2,3)
Value Mode Description
xSPI Reserved
1I2C Slave Read
0I2C Slave Write
1I2C Master Transmit is in progress
0I2C Master Transmit is not in progress
Bit 1 – UA Update Address bit (10-Bit Slave mode only)
Value Mode Description
xAll other modes Reserved
1I2C 10-bit Slave Indicates that the user needs to update the address in the SSPxADD
register
0I2C 10-bit Slave Address does not need to be updated
Bit 0 – BF
Buffer Full Status bit(5)
Value Mode Description
1I2C Transmit Character written to SSPxBUF has not been sent
0I2C Transmit SSPxBUF is ready for next character
1SPI and I2C Receive Received character in SSPxBUF has not been read
0SPI and I2C Receive Received character in SSPxBUF has been read
Note: 
1. This bit is cleared on Reset and when SSPEN is cleared.
2. In I2C Slave mode this bit holds the R/W bit information following the last address match. This bit is
only valid from the address match to the next Start bit, Stop bit or not ACK bit.
3. ORing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSP is in Active mode.
4. Polarity of clock state is set by the CKP bit.
5. I2C receive status does not include ACK and Stop bits.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 523
27.9.2 SSPxCON1
Name:  SSPxCON1
Address:  0xF95,0xE91
MSSP Control Register 1
Bit 7 6 5 4 3 2 1 0
WCOL SSPOV SSPEN CKP SSPM[3:0]
Access R/W/HS R/W/HS R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – WCOL
Write Collision Detect bit
Value Mode Description
1SPI A write to the SSPxBUF register was attempted while the previous
byte was still transmitting (must be cleared by software)
1I2C Master transmit A write to the SSPxBUF register was attempted while the I2C
conditions were not valid for a transmission to be started (must be
cleared by software)
1I2C Slave transmit The SSPxBUF register is written while it is still transmitting the
previous word (must be cleared in software)
0SPI or I2C Master or
Slave transmit
No collision
xMaster or Slave
receive
Don't care
Bit 6 – SSPOV
Receive Overflow Indicator bit(1)
Value Mode Description
1SPI Slave A byte is received while the SSPxBUF register is still holding the
previous byte. The user must read SSPxBUF, even if only
transmitting data, to avoid setting overflow. (must be cleared in
software)
1I2C Receive A byte is received while the SSPxBUF register is still holding the
previous byte (must be cleared in software)
0SPI Slave or I2C
Receive
No overflow
xSPI Master or I2C
Master transmit
Don't care
Bit 5 – SSPEN
Master Synchronous Serial Port Enable bit.(2)
Value Mode Description
1SPI Enables the serial port. The SCKx, SDOx, SDIx, and SSx pin selections must be
made with the PPS controls. Each signal must be configured with the corresponding
TRIS control to the direction appropriate for the mode selected.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 524
Value Mode Description
1I2C Enables the serial port. The SDAx and SCLx pin selections must be made with the
PPS controls. Since both signals are bidirectional the PPS input pin and PPS output
pin selections must be made that specify the same pin. Both pins must be configured
as inputs with the corresponding TRIS controls.
0All Disables serial port and configures these pins as I/O port pins
Bit 4 – CKP
SCK Release Control bit
Value Mode Description
1SPI Idle state for the clock is a high level
0SPI Idle state for the clock is a low level
1I2C Slave Releases clock
0I2C Slave Holds clock low (clock stretch), used to ensure data setup time
xI2C Master Unused in this mode
Bits 3:0 – SSPM[3:0]
Master Synchronous Serial Port Mode Select bits(4)
Value Description
1111 I2C Slave mode: 10-bit address with Start and Stop bit interrupts enabled
1110 I2C Slave mode: 7-bit address with Start and Stop bit interrupts enabled
1101 Reserved - do not use
1100 Reserved - do not use
1011 I2C Firmware Controlled Master mode (slave Idle)
1010 SPI Master mode: Clock = FOSC/(4*(SSPxADD+1)). SSPxADD must be greater than 0.(3)
1001 Reserved - do not use
1000 I2C Master mode: Clock = FOSC/(4 * (SSPxADD + 1))
0111 I2C Slave mode: 10-bit address
0110 I2C Slave mode: 7-bit address
0101 SPI Slave mode: Clock = SCKx pin. SSx pin control is disabled
0100 SPI Slave mode: Clock = SCKx pin. SSx pin control is enabled
0011 SPI Master mode: Clock = TMR2 output/2
0010 SPI Master mode: Clock = Fosc/64
0001 SPI Master mode: Clock = Fosc/16
0000 SPI Master mode: Clock = Fosc/4
Note: 
1. In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated
by writing to the SSPxBUF register.
2. When enabled, these pins must be properly configured as inputs or outputs.
3. SSPxADD = 0 is not supported.
4. Bit combinations not specifically listed here are either reserved or implemented in I2C mode only.
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 525
27.9.3 SSPxCON2
Name:  SSPxCON2
Address:  0xF96,0xE92
Control Register for I2C Operation Only
MSSP Control Register 2
Bit 7 6 5 4 3 2 1 0
GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
Access R/W R/W/HC R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – GCEN
General Call Enable bit (Slave mode only)
Value Mode Description
xMaster mode Don't care
1Slave mode General call is enabled
0Slave mode General call is not enabled
Bit 6 – ACKSTAT Acknowledge Status bit (Master Transmit mode only)
Value Description
1Acknowledge was not received from slave
0Acknowledge was received from slave
Bit 5 – ACKDT
Acknowledge Data bit (Master Receive mode only)(1)
Value Description
1Not Acknowledge
0Acknowledge
Bit 4 – ACKEN
Acknowledge Sequence Enable bit(2)
Value Description
1Initiates Acknowledge sequence on SDAx and SCLx pins and transmits ACKDT data bit;
automatically cleared by hardware
0Acknowledge sequence is Idle
Bit 3 – RCEN
Receive Enable bit (Master Receive mode only)(2)
Value Description
1Enables Receive mode for I2C
0Receive is Idle
Bit 2 – PEN
Stop Condition Enable bit (Master mode only)(2)
Value Description
1Initiates Stop condition on SDAx and SCLx pins; automatically cleared by hardware
0Stop condition is Idle
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(MSSP) Master Synchronous Serial Port Module
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Bit 1 – RSEN
Repeated Start Condition Enable bit (Master mode only)(2)
Value Description
1Initiates Repeated Start condition on SDAx and SCLx pins; automatically cleared by
hardware
0Repeated Start condition is Idle
Bit 0 – SEN
Start Condition Enable bit (Master mode only)(2)
Value Description
1Initiates Start condition on SDAx and SCLx pins; automatically cleared by hardware
0Start condition is Idle
Note: 
1. The value that will be transmitted when the user initiates an Acknowledge sequence at the end of a
receive.
2. If the I2C module is active, these bits may not be set (no spooling) and the SSPxBUF may not be
written (or writes to the SSPxBUF are disabled).
PIC18F26/45/46Q10
(MSSP) Master Synchronous Serial Port Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 527
27.9.4 SSPxCON3
Name:  SSPxCON3
Address:  0xF97,0xE93
MSSP Control Register 3
Bit 7 6 5 4 3 2 1 0
ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
Access R/HS/HC R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – ACKTIM Acknowledge Time Status bit
Unused in Master mode.
Value Mode Description
xSPI or I2C Master This bit is not used
1I2C Slave and AHEN = 1 or
DHEN = 1
Eighth falling edge of SCL has occurred and the ACK/
NACK state is active
0I2C Slave ACK/NACK state is not active. Transitions low on ninth
rising edge of SCL.
Bit 6 – PCIE
Stop Condition Interrupt Enable bit(1)
Value Mode Description
xSPI or SSPM = 1111 or 0111 Don't care
1SSPM1111 and SSPM0111 Enable interrupt on detection of Stop condition
0SSPM1111 and SSPM0111 Stop detection interrupts are disabled
Bit 5 – SCIE Start Condition Interrupt Enable bit
Value Mode Description
xSPI or SSPM = 1111 or 0111 Don't care
1SSPM1111 and SSPM0111 Enable interrupt on detection of Start condition
0SSPM1111 and SSPM0111 Start detection interrupts are disabled
Bit 4 – BOEN
Buffer Overwrite Enable bit(2)
Value Mode Description
1SPI SSPxBUF is updated every time a new data byte is available, ignoring the BF bit
0SPI If a new byte is receive with BF set then SSPOV is set and SSPxBUF is not updated
1I2C SSPxBUF is updated every time a new data byte is available, ignoring the SSPOV
effect on updating the buffer
0I2C SSPxBUF is only updated when SSPOV is clear
Bit 3 – SDAHT SDA Hold Time Selection bit
Value Mode Description
xSPI Not used in SPI mode
1I2C Minimum of 300ns hold time on SDA after the falling edge of SCL
0I2C Minimum of 100ns hold time on SDA after the falling edge of SCL
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Bit 2 – SBCDE Slave Mode Bus Collision Detect Enable bit
Unused in Master mode.
Value Mode Description
xSPI or I2C Master Don't care
1I2C Slave Collision detection is enabled
0I2C Slave Collision detection is not enabled
Bit 1 – AHEN Address Hold Enable bit
Value Mode Description
xSPI or I2C Master Don't care
1I2C Slave Address hold is enabled. As a result CKP is cleared after the eighth
falling SCL edge of an address byte reception. Software must set the
CKP bit to resume operation.
0I2C Slave Address hold is not enabled
Bit 0 – DHEN Data Hold Enable bit
Value Mode Description
xSPI or I2C Master Don't care
1I2C Slave Data hold is enabled. As a result CKP is cleared after the eighth falling
SCL edge of a data byte reception. Software must set the CKP bit to
resume operation.
0I2C Slave Data hold is not enabled
Note: 
1. This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as
enabled.
2. For daisy-chained SPI operation; allows the user to ignore all but the last received byte. SSPOV is
still set when a new byte is received and BF = 1, but hardware continues to write the most recent
byte to SSPxBUF.
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27.9.5 SSPxBUF
Name:  SSPxBUF
Address:  0xF91,0xE8D
MSSP Data Buffer Register
Bit 7 6 5 4 3 2 1 0
BUF[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 7:0 – BUF[7:0] MSSP Input and Output Data Buffer bits
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27.9.6 SSPxADD
Name:  SSPxADD
Address:  0xF92,0xE8E
MSSP Baud Rate Divider and Address Register
Bit 7 6 5 4 3 2 1 0
ADD[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – ADD[7:0]
SPI and I2C Master: Baud rate divider
I2C Slave: Address bits
Value Mode Description
3 to
255
SPI and I2C Master Baud rate divider. SCK/SCL pin clock period = ((n + 1) *4)/FOSC.
Values less than 3 are not valid.
2,4,6,8 I2C 10-bit Slave MS
Address
Bits 7-3 and Bit 0 are not used and are don't care. Bits 2:1 are bits
9:8 of the 10-bit Slave Most Significant Address
nI2C 10-bit Slave LS
Address
Bits 7:0 of 10-Bit Slave Least Significant Address
2*(1 to
127)
I2C 7-bit Slave Bit 0 is not used and is don't care. Bits 7:1 are the 7-bit Slave
Address
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27.9.7 SSPxMSK
Name:  SSPxMSK
Address:  0xF93,0xE8F
MSSP Address Mask Register
Bit 7 6 5 4 3 2 1 0
MSK[6:0] MSK0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 1 1 1 1 1 1 1 1
Bits 7:1 – MSK[6:0] Mask bits
Value Mode Description
1I2C Slave The received address bit n is compared to SSPxADD bit n to detect I2C address
match
0I2C Slave The received address bit n is not used to detect I2C address match
Bit 0 – MSK0
Mask bit for I2C 10-bit Slave mode
Value Mode Description
1I2C 10-bit Slave The received address bit 0 is compared to SSPxADD bit 0 to detect I2C
address match
0I2C 10-bit Slave The received address bit 0 is not used to detect I2C address match
xSPI or I2C 7-bit Don't care
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28. (EUSART) Enhanced Universal Synchronous Asynchronous Receiver
Transmitter
The Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) module is a serial
I/O communications peripheral. It contains all the clock generators, shift registers and data buffers
necessary to perform an input or output serial data transfer independent of device program execution.
The EUSART, also known as a Serial Communications Interface (SCI), can be configured as a full-duplex
asynchronous system or half-duplex synchronous system. Full-Duplex mode is useful for communications
with peripheral systems, such as CRT terminals and personal computers. Half-Duplex Synchronous
mode is intended for communications with peripheral devices, such as A/D or D/A integrated circuits,
serial EEPROMs or other microcontrollers. These devices typically do not have internal clocks for baud
rate generation and require the external clock signal provided by a master synchronous device.
The EUSART module includes the following capabilities:
Full-duplex asynchronous transmit and receive
Two-character input buffer
One-character output buffer
Programmable 8-bit or 9-bit character length
Address detection in 9-bit mode
Input buffer overrun error detection
Received character framing error detection
Half-duplex synchronous master
Half-duplex synchronous slave
Programmable clock polarity in Synchronous modes
Sleep operation
The EUSART module implements the following additional features, making it ideally suited for use in
Local Interconnect Network (LIN) bus systems:
Automatic detection and calibration of the baud rate
Wake-up on Break reception
13-bit Break character transmit
Block diagrams of the EUSART transmitter and receiver are shown in Figure 28-1 and Figure 28-2.
The operation of the EUSART module consists of six registers:
Transmit Status and Control (28.6.2 TXxSTA)
Receive Status and Control (28.6.1 RCxSTA)
Baud Rate Control (28.6.3 BAUDxCON)
Baud Rate Value (28.6.4 SPxBRG)
Receive Data Register (28.6.5 RCxREG)
Transmit Data Register (28.6.6 TXxREG)
The RXx/DTx and TXx/CKx input pins are selected with the RXxPPS and TXxPPS registers, respectively.
TXx, CKx, and DTx output pins are selected with each pin’s RxyPPS register. Since the RX input is
coupled with the DT output in Synchronous mode, it is the user’s responsibility to select the same pin for
both of these functions when operating in Synchronous mode. The EUSART control logic will control the
data direction drivers automatically.
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Figure 28-1. EUSART Transmit Block Diagram
TXREG register
8
Pin Buffer
and Control
TXIF
TRMT
TX9D
Data bus
8TXIE
Inte rrupt
RXx/DTx Pin
TX_out
TX9
TXEN
Transmit Shift Register (TSR)
(8) 0
MSb LSb
÷ n
Multiplier x4
SYNC
BRGH
BRG16
x16 x64
1
1
1
1
1
x
x
x 0
0
0
0
0
0
0
n
+ 1
SPBRG H SPBRGL
Baud Rate Generator FOSC
BRG16
Rev. 10-000 113C
2/15/201 7
PPS
RxyPPS(1)
0
1
1
0
SYNC
CSRC
PPS
CKx Pin
CKPPS(2)
PPS
RxyPPS(2)
SYNC
CSRC
TXx/CKx Pi n
Not e 1: In Synchronous mod e, the DT output and RX input PPS
selections should enable the same pin.
2: In Master Syn chronous mode the TX output and CK inpu t
PPS selections shou ld enable the sa me pin.
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Figure 28-2. EUSART Receive Block Diagram
÷ n
Multiplier x4
SYNC
BRGH
BRG16
x16 x64
1
1
1
1
1
x
x
x 0
0
0
0
0
0
0
n
+ 1
SPBRG H SPBRGL
Baud Rate Generator FOSC
BRG16
SPEN
CRE N OERR RCIDL
Pin Buffer
and Control
Data
Recovery
RXx/DTx pin
Stop (8) 7 Start01
MSb LSb
RSR Register
RX9
FERR RX9D RCREG Register
FIFO
8
Data B us
RCxIE
RCxIF Inte rrupt
Rev. 10-000 114B
2/15/201 7
PPS
RXPPS(1)
Not e 1: In S ynchronous mod e, the DT output and RX input PPS
selectio ns should en able the same pin.
2: In Master S ynchr onous mode the TX output and CK input
PPS selections shou ld enable the sa me pin.
1
0
SYNC
CSRC
PPS
CKx Pin
CKPPS(2)
28.1 EUSART Asynchronous Mode
The EUSART transmits and receives data using the standard non-return-to-zero (NRZ) format. NRZ is
implemented with two levels: a VOH Mark state which represents a ‘1’ data bit, and a VOL Space state
which represents a ‘0’ data bit. NRZ refers to the fact that consecutively transmitted data bits of the same
value stay at the output level of that bit without returning to a neutral level between each bit transmission.
An NRZ transmission port idles in the Mark state. Each character transmission consists of one Start bit
followed by eight or nine data bits and is always terminated by one or more Stop bits. The Start bit is
always a space and the Stop bits are always marks. The most common data format is eight bits. Each
transmitted bit persists for a period of 1/(Baud Rate). An on-chip dedicated 8-bit/16-bit Baud Rate
Generator is used to derive standard baud rate frequencies from the system oscillator. See Table 28-2 for
examples of baud rate configurations.
The EUSART transmits and receives the LSb first. The EUSART’s transmitter and receiver are
functionally independent, but share the same data format and baud rate. Parity is not supported by the
hardware, but can be implemented in software and stored as the ninth data bit.
28.1.1 EUSART Asynchronous Transmitter
The Figure 28-1 is a simplified representation of the transmitter. The heart of the transmitter is the serial
Transmit Shift Register (TSR), which is not directly accessible by software. The TSR obtains its data from
the transmit buffer, which is the TXxREG register.
28.1.1.1 Enabling the Transmitter
The EUSART transmitter is enabled for asynchronous operations by configuring the following three
control bits:
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TXEN = 1 (enables the transmitter circuitry of the EUSART)
SYNC = 0 (configures the EUSART for asynchronous operation)
SPEN = 1 (enables the EUSART and automatically enables the output drivers for the RxyPPS
selected as the TXx/CKx output)
All other EUSART control bits are assumed to be in their default state.
If the TXx/CKx pin is shared with an analog peripheral, the analog I/O function must be disabled by
clearing the corresponding ANSEL bit.
Important:  The TXxIF Transmitter Interrupt flag is set when the TXEN enable bit is set and the
TSR is idle.
28.1.1.2 Transmitting Data
A transmission is initiated by writing a character to the TXxREG register. If this is the first character, or the
previous character has been completely flushed from the TSR, the data in the TXxREG is immediately
transferred to the TSR register. If the TSR still contains all or part of a previous character, the new
character data is held in the TXxREG until the Stop bit of the previous character has been transmitted.
The pending character in the TXxREG is then transferred to the TSR in one TCY immediately following the
Stop bit transmission. The transmission of the Start bit, data bits and Stop bit sequence commences
immediately following the transfer of the data to the TSR from the TXxREG.
28.1.1.3 Transmit Data Polarity
The polarity of the transmit data can be controlled with the SCKP bit of the BAUDxCON register. The
default state of this bit is ‘0’ which selects high true transmit idle and data bits. Setting the SCKP bit to ‘1
will invert the transmit data resulting in low true idle and data bits. The SCKP bit controls transmit data
polarity in Asynchronous mode only. In Synchronous mode, the SCKP bit has a different function. See the
28.3.1.2 Clock Polarity section for more detail.
28.1.1.4 Transmit Interrupt Flag
The TXxIF interrupt flag bit of the PIRx register is set whenever the EUSART transmitter is enabled and
no character is being held for transmission in the TXxREG. In other words, the TXxIF bit is only clear
when the TSR is busy with a character and a new character has been queued for transmission in the
TXxREG. The TXxIF flag bit is not cleared immediately upon writing TXxREG. TXxIF becomes valid in the
second instruction cycle following the write execution. Polling TXxIF immediately following the TXxREG
write will return invalid results. The TXxIF bit is read-only, it cannot be set or cleared by software.
The TXxIF interrupt can be enabled by setting the TXxIE interrupt enable bit of the PIEx register.
However, the TXxIF flag bit will be set whenever the TXxREG is empty, regardless of the state of TXxIE
enable bit.
To use interrupts when transmitting data, set the TXxIE bit only when there is more data to send. Clear
the TXxIE interrupt enable bit upon writing the last character of the transmission to the TXxREG.
28.1.1.5 TSR Status
The TRMT bit of the TXxSTA register indicates the status of the TSR register. This is a read-only bit. The
TRMT bit is set when the TSR register is empty and is cleared when a character is transferred to the TSR
register from the TXxREG. The TRMT bit remains clear until all bits have been shifted out of the TSR
register. No interrupt logic is tied to this bit, so the user needs to poll this bit to determine the TSR status.
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Important:  The TSR register is not mapped in data memory, so it is not available to the user.
28.1.1.6 Transmitting 9-Bit Characters
The EUSART supports 9-bit character transmissions. When the TX9 bit of the TXxSTA register is set, the
EUSART will shift nine bits out for each character transmitted. The TX9D bit of the TXxSTA register is the
ninth, and Most Significant data bit. When transmitting 9-bit data, the TX9D data bit must be written
before writing the eight Least Significant bits into the TXxREG. All nine bits of data will be transferred to
the TSR shift register immediately after the TXxREG is written.
A special 9-bit Address mode is available for use with multiple receivers. See the 28.1.2.7 Address
Detection section for more information on the Address mode.
28.1.1.7 Asynchronous Transmission Setup
1. Initialize the SPxBRGH, SPxBRGL register pair and the BRGH and BRG16 bits to achieve the
desired baud rate (see 28.2 EUSART Baud Rate Generator (BRG)).
2. Select the transmit output pin by writing the appropriate value to the RxyPPS register.
3. Enable the asynchronous serial port by clearing the SYNC bit and setting the SPEN bit.
4. If 9-bit transmission is desired, set the TX9 control bit. A set ninth data bit will indicate that the eight
Least Significant data bits are an address when the receiver is set for address detection.
5. Set SCKP bit if inverted transmit is desired.
6. Enable the transmission by setting the TXEN control bit. This will cause the TXxIF interrupt bit to be
set.
7. If interrupts are desired, set the TXxIE interrupt enable bit of the PIEx register
8. An interrupt will occur immediately provided that the GIE and PEIE bits of the INTCON register are
also set.
9. If 9-bit transmission is selected, the ninth bit should be loaded into the TX9D data bit.
10. Load 8-bit data into the TXxREG register. This will start the transmission.
Figure 28-3. Asynchronous Transmission
Rev. 10-000 115A
2/7/201 7
Write to TXxREG
BRG Output
(Shift Clock)
TXx/CKx pin
TXxIF bit
(Transmit Buffer
Reg Empty Flag)
TRMT bit
(Transmit Shift
Reg Empty Flag)
Start bit bit 0 bit 1 bit 7/8 Stop bit
1 TCY
Word 1
Word 1
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Figure 28-4. Asynchronous Transmission (Back-to-Back)
Rev. 10-000 116A
2/7/201 7
Write to TXxREG
BRG Output
(Shift Clock)
TXx/CKx pin
TXxIF bit
(Transmit Buffer
Reg Empty Flag)
TRMT bit
(Transmit Shift
Reg Empty Flag)
Start bit bit 0 bit 1 bit 7/8 Stop bit
1 TCY
Word 1
Start bit bit 0
Word 2
Word 1 Word 2
28.1.2 EUSART Asynchronous Receiver
The Asynchronous mode is typically used in RS-232 systems. A simplified representation of the receiver
is shown in the Figure 28-2. The data is received on the RXx/DTx pin and drives the data recovery block.
The data recovery block is actually a high-speed shifter operating at 16 times the baud rate, whereas the
serial Receive Shift Register (RSR) operates at the bit rate. When all eight or nine bits of the character
have been shifted in, they are immediately transferred to a two character First-In-First-Out (FIFO)
memory. The FIFO buffering allows reception of two complete characters and the start of a third character
before software must start servicing the EUSART receiver. The FIFO and RSR registers are not directly
accessible by software. Access to the received data is via the RCxREG register.
28.1.2.1 Enabling the Receiver
The EUSART receiver is enabled for asynchronous operation by configuring the following three control
bits:
CREN = 1 (enables the receiver circuitry of the EUSART)
SYNC = 0 (configures the EUSART for asynchronous operation)
SPEN = 1 (enables the EUSART)
All other EUSART control bits are assumed to be in their default state.
The user must set the RXxPPS register to select the RXx/DTx I/O pin and set the corresponding TRIS bit
to configure the pin as an input.
Important:  If the RX/DT function is on an analog pin, the corresponding ANSEL bit must be
cleared for the receiver to function.
28.1.2.2 Receiving Data
The receiver data recovery circuit initiates character reception on the falling edge of the first bit. The first
bit, also known as the Start bit, is always a zero. The data recovery circuit counts one-half bit time to the
center of the Start bit and verifies that the bit is still a zero. If it is not a zero then the data recovery circuit
aborts character reception, without generating an error, and resumes looking for the falling edge of the
Start bit. If the Start bit zero verification succeeds then the data recovery circuit counts a full bit time to
the center of the next bit. The bit is then sampled by a majority detect circuit and the resulting ‘0’ or ‘1’ is
shifted into the RSR. This repeats until all data bits have been sampled and shifted into the RSR. One
final bit time is measured and the level sampled. This is the Stop bit, which is always a ‘1’. If the data
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recovery circuit samples a ‘0’ in the Stop bit position then a framing error is set for this character,
otherwise the framing error is cleared for this character. See the 28.1.2.4 Receive Framing Error section
for more information on framing errors.
Immediately after all data bits and the Stop bit have been received, the character in the RSR is
transferred to the EUSART receive FIFO and the RCxIF interrupt flag bit of the PIRx register is set. The
top character in the FIFO is transferred out of the FIFO by reading the RCxREG register.
Important:  If the receive FIFO is overrun, no additional characters will be received until the
overrun condition is cleared. See the 28.1.2.5 Receive Overrun Error section for more
information.
28.1.2.3 Receive Interrupts
The RCxIF interrupt flag bit of the PIRx register is set whenever the EUSART receiver is enabled and
there is an unread character in the receive FIFO. The RCxIF interrupt flag bit is read-only, it cannot be set
or cleared by software.
RCxIF interrupts are enabled by setting all of the following bits:
RCxIE, Interrupt Enable bit of the PIEx register
PEIE, Peripheral Interrupt Enable bit of the INTCON register
GIE, Global Interrupt Enable bit of the INTCON register
The RCxIF interrupt flag bit will be set when there is an unread character in the FIFO, regardless of the
state of interrupt enable bits.
28.1.2.4 Receive Framing Error
Each character in the receive FIFO buffer has a corresponding framing error Status bit. A framing error
indicates that a Stop bit was not seen at the expected time. The framing error status is accessed via the
FERR bit of the RCxSTA register. The FERR bit represents the status of the top unread character in the
receive FIFO. Therefore, the FERR bit must be read before reading the RCxREG.
The FERR bit is read-only and only applies to the top unread character in the receive FIFO. A framing
error (FERR = 1) does not preclude reception of additional characters. It is not necessary to clear the
FERR bit. Reading the next character from the FIFO buffer will advance the FIFO to the next character
and the next corresponding framing error.
The FERR bit can be forced clear by clearing the SPEN bit of the RCxSTA register which resets the
EUSART. Clearing the CREN bit of the RCxSTA register does not affect the FERR bit. A framing error by
itself does not generate an interrupt.
Important:  If all receive characters in the receive FIFO have framing errors, repeated reads of
the RCxREG will not clear the FERR bit.
28.1.2.5 Receive Overrun Error
The receive FIFO buffer can hold two characters. An overrun error will be generated if a third character, in
its entirety, is received before the FIFO is accessed. When this happens the OERR bit of the RCxSTA
register is set. The characters already in the FIFO buffer can be read but no additional characters will be
received until the error is cleared. The error must be cleared by either clearing the CREN bit of the
RCxSTA register or by resetting the EUSART by clearing the SPEN bit of the RCxSTA register.
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28.1.2.6 Receiving 9-Bit Characters
The EUSART supports 9-bit character reception. When the RX9 bit of the RCxSTA register is set the
EUSART will shift nine bits into the RSR for each character received. The RX9D bit of the RCxSTA
register is the ninth and Most Significant data bit of the top unread character in the receive FIFO. When
reading 9-bit data from the receive FIFO buffer, the RX9D data bit must be read before reading the eight
Least Significant bits from the RCxREG.
28.1.2.7 Address Detection
A special Address Detection mode is available for use when multiple receivers share the same
transmission line, such as in RS-485 systems. Address detection is enabled by setting the ADDEN bit of
the RCxSTA register.
Address detection requires 9-bit character reception. When address detection is enabled, only characters
with the ninth data bit set will be transferred to the receive FIFO buffer, thereby setting the RCxIF interrupt
bit. All other characters will be ignored.
Upon receiving an address character, user software determines if the address matches its own. Upon
address match, user software must disable address detection by clearing the ADDEN bit before the next
Stop bit occurs. When user software detects the end of the message, determined by the message
protocol used, software places the receiver back into the Address Detection mode by setting the ADDEN
bit.
28.1.2.8 Asynchronous Reception Setup
1. Initialize the SPxBRGH:SPxBRGL register pair and the BRGH and BRG16 bits to achieve the
desired baud rate (see the 28.2 EUSART Baud Rate Generator (BRG) section).
2. Set the RXxPPS register to select the RXx/DTx input pin.
3. Clear the ANSEL bit for the RXx pin (if applicable).
4. Enable the serial port by setting the SPEN bit. The SYNC bit must be clear for asynchronous
operation.
5. If interrupts are desired, set the RCxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
6. If 9-bit reception is desired, set the RX9 bit.
7. Enable reception by setting the CREN bit.
8. The RCxIF interrupt flag bit will be set when a character is transferred from the RSR to the receive
buffer. An interrupt will be generated if the RCxIE interrupt enable bit was also set.
9. Read the RCxSTA register to get the error flags and, if 9-bit data reception is enabled, the ninth
data bit.
10. Get the received eight Least Significant data bits from the receive buffer by reading the RCxREG
register.
11. If an overrun occurred, clear the OERR flag by clearing the CREN receiver enable bit.
28.1.2.9 9-Bit Address Detection Mode Setup
This mode would typically be used in RS-485 systems. To set up an Asynchronous Reception with
Address Detect Enable follow these steps:
1. Initialize the SPxBRGH:SPxBRGL register pair and the BRGH and BRG16 bits to achieve the
desired baud rate (see the 28.2 EUSART Baud Rate Generator (BRG) section).
2. Set the RXxPPS register to select the RXx input pin.
3. Clear the ANSEL bit for the RXx pin (if applicable).
4. Enable the serial port by setting the SPEN bit. The SYNC bit must be clear for asynchronous
operation.
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5. If interrupts are desired, set the RCxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
6. Enable 9-bit reception by setting the RX9 bit.
7. Enable address detection by setting the ADDEN bit.
8. Enable reception by setting the CREN bit.
9. The RCxIF interrupt flag bit will be set when a character with the ninth bit set is transferred from the
RSR to the receive buffer. An interrupt will be generated if the RCxIE Interrupt Enable bit is also
set.
10. Read the RCxSTA register to get the error flags. The ninth data bit will always be set.
11. Get the received eight Least Significant data bits from the receive buffer by reading the RCxREG
register. Software determines if this is the device’s address.
12. If an overrun occurred, clear the OERR flag by clearing the CREN receiver enable bit.
13. If the device has been addressed, clear the ADDEN bit to allow all received data into the receive
buffer and generate interrupts.
Figure 28-5. Asynchronous Reception
Rev. 10-000 117A
2/8/201 7
RXx/DTx
pin
Start
bit bit 0
Word 1
bit 7/8 Stop
bit
Start
bit bit 0 bit 7/8 Stop
bit
Start
bit bit 0 bit 7/8 Stop
bit
Word 3Word 2
Rcv Shift Reg
Rcv Buffer Reg
Word 1
RCxREG
Word 2
RCxREG
RCIDL
Read
RCxREG
OERR Flag
CREN
(software clear)
RCxIF
(Interrupt flag)
Note: This timing diagram shows three bytes appearing on the RXx input. The OERR flag is set because the
RCxREG is not read before the third word is received.
28.1.3 Clock Accuracy with Asynchronous Operation
The factory calibrates the internal oscillator block output (INTOSC). However, the INTOSC frequency may
drift as VDD or temperature changes, and this directly affects the asynchronous baud rate. Two methods
may be used to adjust the baud rate clock, but both require a reference clock source of some kind.
The first (preferred) method uses the OSCTUNE register to adjust the INTOSC output. Adjusting the
value in the OSCTUNE register allows for fine resolution changes to the system clock source.
The other method adjusts the value in the Baud Rate Generator. This can be done automatically with the
Auto-Baud Detect feature (see 28.2.1 Auto-Baud Detect). There may not be fine enough resolution when
adjusting the Baud Rate Generator to compensate for a gradual change in the peripheral clock frequency.
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28.2 EUSART Baud Rate Generator (BRG)
The Baud Rate Generator (BRG) is an 8-bit or 16-bit timer that is dedicated to the support of both the
asynchronous and synchronous EUSART operation. By default, the BRG operates in 8-bit mode. Setting
the BRG16 bit of the BAUDxCON register selects 16-bit mode.
The SPxBRGH, SPxBRGL register pair determines the period of the free-running baud rate timer. In
Asynchronous mode the multiplier of the baud rate period is determined by both the BRGH bit of the
TXxSTA register and the BRG16 bit of the BAUDxCON register. In Synchronous mode, the BRGH bit is
ignored.
Table 28-1 contains the formulas for determining the baud rate. Figure 28-6 provides a sample calculation
for determining the baud rate and baud rate error.
Typical baud rates and error values for various asynchronous modes have been computed and are
shown in Table 28-2. It may be advantageous to use the high baud rate (BRGH = 1), or the 16-bit BRG
(BRG16 = 1) to reduce the baud rate error. The 16-bit BRG mode is used to achieve slow baud rates for
fast oscillator frequencies. The BRGH bit is used to achieve very high baud rates.
Writing a new value to the SPxBRGH, SPxBRGL register pair causes the BRG timer to be reset (or
cleared). This ensures that the BRG does not wait for a timer overflow before outputting the new baud
rate.
If the system clock is changed during an active receive operation, a receive error or data loss may result.
To avoid this problem, check the status of the RCIDL bit to make sure that the receive operation is idle
before changing the system clock.
Figure 28-6. Calculating Baud Rate Error
For a device with Fosc of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG:
 =
6 + 1
Solving for SPxBRG:
 =
6 1
 =16000000
64 × 9600 1
 = 25.042 25
 =16000000
64 × 25 + 1
 = 9615
 = 

 =9615 9600
9600
 = 0.16 %
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Table 28-1. Baud Rate Formulas
Configuration Bits
BRG/EUSART Mode Baud Rate Formula
SYNC BRG16 BRGH
0 0 0 8-bit/Asynchronous FOSC/[64 (n+1)]
0 0 1 8-bit/Asynchronous
FOSC/[16 (n+1)]
0 1 0 16-bit/Asynchronous
0 1 1 16-bit/Asynchronous
FOSC/[4 (n+1)]
1 0 x 8-bit/Synchronous
1 1 x 16-bit/Synchronous
Note: x = Don’t care, n = value of SPxBRGH:SPxBRGL register pair.
Table 28-2. Sample Baud Rates for Asynchronous Modes
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 0
FOSC = 32.000 MHz FOSC = 20.000 MHz FOSC = 18.432 MHz FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300
1200 1221 1.73 255 1200 0.00 239 1200 0.00 143
2400 2404 0.16 207 2404 0.16 129 2400 0.00 119 2400 0.00 71
9600 9615 0.16 51 9470 -1.36 32 9600 0.00 29 9600 0.00 17
10417 10417 0.00 47 10417 0.00 29 10286 -1.26 27 10165 -2.42 16
19.2k 19.23k 0.16 25 19.53k 1.73 15 19.20k 0.00 14 19.20k 0.00 8
57.6k 55.55k -3.55 3 57.60k 0.00 7 57.60k 0.00 2
115.2k
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 0
Fosc = 8.000 MHz Fosc = 4.000 MHz Fosc = 3.6864 MHz Fosc = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300 0.16 207 300 0.00 191 300 0.16 51
1200 1202 0.16 103 1202 0.16 51 1200 0.00 47 1202 0.16 12
2400 2404 0.16 51 2404 0.16 25 2400 0.00 23
9600 9615 0.16 12 9600 0.00 5
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10417 10417 0.00 11 10417 0.00 5
19.2k 19.20k 0.00 2
57.6k 57.60k 0.00 0
115.2k
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 0
Fosc = 32.000 MHz Fosc = 20.000 MHz Fosc = 18.432 MHz Fosc = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300
1200
2400
9600 9615 0.16 207 9615 0.16 129 9600 0.00 119 9600 0.00 71
10417 10417 0.00 191 10417 0.00 119 10378 -0.37 110 10473 0.53 65
19.2k 19.23k 0.16 103 19.23k 0.16 64 19.20k 0.00 59 19.20k 0.00 35
57.6k 57.14k -0.79 34 56.82k -1.36 21 57.60k 0.00 19 57.60k 0.00 11
115.2k 117.64k 2.12 16 113.64k -1.36 10 115.2k 0.00 9 115.2k 0.00 5
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 0
Fosc = 8.000 MHz Fosc = 4.000 MHz Fosc = 3.6864 MHz Fosc = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300 0.16 207
1200 1202 0.16 207 1200 0.00 191 1202 0.16 51
2400 2404 0.16 207 2404 0.16 103 2400 0.00 95 2404 0.16 25
9600 9615 0.16 51 9615 0.16 25 9600 0.00 23
10417 10417 0.00 47 10417 0.00 23 10473 0.53 21 10417 0.00 5
19.2k 19231 0.16 25 19.23k 0.16 12 19.2k 0.00 11
57.6k 55556 -3.55 8 57.60k 0.00 3
115.2k 115.2k 0.00 1
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BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 1
Fosc = 32.000 MHz Fosc = 20.000 MHz Fosc = 18.432 MHz Fosc = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300.0 0.00 6666 300.0 -0.01 4166 300.0 0.00 3839 300.0 0.00 2303
1200 1200 -0.02 3332 1200 -0.03 1041 1200 0.00 959 1200 0.00 575
2400 2401 -0.04 832 2399 -0.03 520 2400 0.00 479 2400 0.00 287
9600 9615 0.16 207 9615 0.16 129 9600 0.00 119 9600 0.00 71
10417 10417 0.00 191 10417 0.00 119 10378 -0.37 110 10473 0.53 65
19.2k 19.23k 0.16 103 19.23k 0.16 64 19.20k 0.00 59 19.20k 0.00 35
57.6k 57.14k -0.79 34 56.818 -1.36 21 57.60k 0.00 19 57.60k 0.00 11
115.2k 117.6k 2.12 16 113.636 -1.36 10 115.2k 0.00 9 115.2k 0.00 5
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 1
Fosc = 8.000 MHz Fosc = 4.000 MHz Fosc = 3.6864 MHz Fosc = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 299.9 -0.02 1666 300.1 0.04 832 300.0 0.00 767 300.5 0.16 207
1200 1199 -0.08 416 1202 0.16 207 1200 0.00 191 1202 0.16 51
2400 2404 0.16 207 2404 0.16 103 2400 0.00 95 2404 0.16 25
9600 9615 0.16 51 9615 0.16 25 9600 0.00 23
10417 10417 0.00 47 10417 0.00 23 10473 0.53 21 10417 0.00 5
19.2k 19.23k 0.16 25 19.23k 0.16 12 19.20k 0.00 11
57.6k 55556 -3.55 8 57.60k 0.00 3
115.2k 115.2k 0.00 1
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
Fosc = 32.000 MHz Fosc = 20.000 MHz Fosc = 18.432 MHz Fosc = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300.0 0.00 26666 300.0 0.00 16665 300.0 0.00 15359 300.0 0.00 9215
1200 1200 0.00 6666 1200 -0.01 4166 1200 0.00 3839 1200 0.00 2303
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2400 2400 0.01 3332 2400 0.02 2082 2400 0.00 1919 2400 0.00 1151
9600 9604 0.04 832 9597 -0.03 520 9600 0.00 479 9600 0.00 287
10417 10417 0.00 767 10417 0.00 479 10425 0.08 441 10433 0.16 264
19.2k 19.18k -0.08 416 19.23k 0.16 259 19.20k 0.00 239 19.20k 0.00 143
57.6k 57.55k -0.08 138 57.47k -0.22 86 57.60k 0.00 79 57.60k 0.00 47
115.2k 115.9k 0.64 68 116.3k 0.94 42 115.2k 0.00 39 115.2k 0.00 23
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
Fosc = 8.000 MHz Fosc = 4.000 MHz Fosc = 3.6864 MHz Fosc = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300.0 0.00 6666 300.0 0.01 3332 300.0 0.00 3071 300.1 0.04 832
1200 1200 -0.02 1666 1200 0.04 832 1200 0.00 767 1202 0.16 207
2400 2401 0.04 832 2398 0.08 416 2400 0.00 383 2404 0.16 103
9600 9615 0.16 207 9615 0.16 103 9600 0.00 95 9615 0.16 25
10417 10417 0 191 10417 0.00 95 10473 0.53 87 10417 0.00 23
19.2k 19.23k 0.16 103 19.23k 0.16 51 19.20k 0.00 47 19.23k 0.16 12
57.6k 57.14k -0.79 34 58.82k 2.12 16 57.60k 0.00 15
115.2k 117.6k 2.12 16 111.1k -3.55 8 115.2k 0.00 7
28.2.1 Auto-Baud Detect
The EUSART module supports automatic detection and calibration of the baud rate.
In the Auto-Baud Detect (ABD) mode, the clock to the BRG is reversed. Rather than the BRG clocking
the incoming RX signal, the RX signal is timing the BRG. The Baud Rate Generator is used to time the
period of a received 55h (ASCII “U”) which is the Sync character for the LIN bus. The unique feature of
this character is that it has five rising edges including the Stop bit edge.
Setting the ABDEN bit of the BAUDxCON register starts the auto-baud calibration sequence. While the
ABD sequence takes place, the EUSART state machine is held in Idle. On the first rising edge of the
receive line, after the Start bit, the SPxBRG begins counting up using the BRG counter clock as shown in
Figure 28-7. The fifth rising edge will occur on the RXx pin at the end of the eighth bit period. At that time,
an accumulated value totaling the proper BRG period is left in the SPxBRGH, SPxBRGL register pair, the
ABDEN bit is automatically cleared and the RCxIF interrupt flag is set. The value in the RCxREG needs
to be read to clear the RCxIF interrupt. RCxREG content should be discarded. When calibrating for
modes that do not use the SPxBRGH register the user can verify that the SPxBRGL register did not
overflow by checking for 00h in the SPxBRGH register.
The BRG auto-baud clock is determined by the BRG16 and BRGH bits as shown in Table 28-3. During
ABD, both the SPxBRGH and SPxBRGL registers are used as a 16-bit counter, independent of the
BRG16 bit setting. While calibrating the baud rate period, the SPxBRGH and SPxBRGL registers are
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clocked at 1/8th the BRG base clock rate. The resulting byte measurement is the average bit time when
clocked at full speed.
Note: 
1. If the WUE bit is set with the ABDEN bit, auto-baud detection will occur on the byte following the
Break character (see 28.2.3 Auto-Wake-up on Break).
2. It is up to the user to determine that the incoming character baud rate is within the range of the
selected BRG clock source. Some combinations of oscillator frequency and EUSART baud rates
are not possible.
3. During the auto-baud process, the auto-baud counter starts counting at one. Upon completion of
the auto-baud sequence, to achieve maximum accuracy, subtract 1 from the SPxBRGH:SPxBRGL
register pair.
Table 28-3. BRG Counter Clock Rates
BRG16 BRGH BRG Base Clock BRG ABD Clock
1 1 FOSC/4 FOSC/32
1 0 FOSC/16 FOSC/128
0 1 FOSC/16 FOSC/128
0 0 FOSC/64 FOSC/512
Note:  During the ABD sequence, SPxBRGL and SPxBRGH registers are both used as a 16-bit
counter, independent of the BRG16 setting.
Figure 28-7. Automatic Baud Rate Calibration
Rev. 10-000 120A
2/13/201 7
BRG Value
RXx/DTx pin
RCxIF bit
(Interrupt Flag)
Read
RCxREG
Edge #1
BRG Clock
SPxBRGH:L
Auto cleared
XXXXh 0000h 001Ch
ABDEN
start bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7
Edge #2 Edge #3 Edge #4 Edge #5
Set by user
001Ch
XXXXh
28.2.2 Auto-Baud Overflow
During the course of automatic baud detection, the ABDOVF bit of the BAUDxCON register will be set if
the baud rate counter overflows before the fifth rising edge is detected on the RXx pin. The ABDOVF bit
indicates that the counter has exceeded the maximum count that can fit in the 16 bits of the
SPxBRGH:SPxBRGL register pair. After the ABDOVF bit has been set, the counter continues to count
until the fifth rising edge is detected on the RXx pin. Upon detecting the fifth RX edge, the hardware will
set the RCxIF interrupt flag and clear the ABDEN bit of the BAUDxCON register. The RCxIF flag can be
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subsequently cleared by reading the RCxREG register. The ABDOVF flag of the BAUDxCON register can
be cleared by software directly.
To terminate the auto-baud process before the RCxIF flag is set, clear the ABDEN bit then clear the
ABDOVF bit of the BAUDxCON register. The ABDOVF bit will remain set if the ABDEN bit is not cleared
first.
28.2.3 Auto-Wake-up on Break
During Sleep mode, all clocks to the EUSART are suspended. Because of this, the Baud Rate Generator
is inactive and a proper character reception cannot be performed. The Auto-Wake-up feature allows the
controller to wake-up due to activity on the RX/DT line. This feature is available only in Asynchronous
mode.
The Auto-Wake-up feature is enabled by setting the WUE bit of the BAUDxCON register. Once set, the
normal receive sequence on RX/DT is disabled, and the EUSART remains in an Idle state, monitoring for
a wake-up event independent of the CPU mode. A wake-up event consists of a high-to-low transition on
the RX/DT line. (This coincides with the start of a Sync Break or a wake-up signal character for the LIN
protocol.)
The EUSART module generates an RCxIF interrupt coincident with the wake-up event. The interrupt is
generated synchronously to the Q clocks in normal CPU operating modes as shown in Figure 28-8, and
asynchronously if the device is in Sleep mode as shown in Figure 28-9. The interrupt condition is cleared
by reading the RCxREG register.
The WUE bit is automatically cleared by the low-to-high transition on the RX line at the end of the Break.
This signals to the user that the Break event is over. At this point, the EUSART module is in Idle mode
waiting to receive the next character.
28.2.3.1 Special Considerations
Break Character
To avoid character errors or character fragments during a wake-up event, the wake-up character must be
all zeros.
When the wake-up is enabled the function works independent of the low time on the data stream. If the
WUE bit is set and a valid non-zero character is received, the low time from the Start bit to the first rising
edge will be interpreted as the wake-up event. The remaining bits in the character will be received as a
fragmented character and subsequent characters can result in framing or overrun errors.
Therefore, the initial character in the transmission must be all ‘0’s. This must be ten or more bit times, 13-
bit times recommended for LIN bus, or any number of bit times for standard RS-232 devices.
Oscillator Start-up Time
Oscillator start-up time must be considered, especially in applications using oscillators with longer start-up
intervals (i.e., LP, XT or HS/PLL mode). The Sync Break (or wake-up signal) character must be of
sufficient length, and be followed by a sufficient interval, to allow enough time for the selected oscillator to
start and provide proper initialization of the EUSART.
WUE Bit
The wake-up event causes a receive interrupt by setting the RCxIF bit. The WUE bit is cleared in
hardware by a rising edge on RX/DT. The interrupt condition is then cleared in software by reading the
RCxREG register and discarding its contents.
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To ensure that no actual data is lost, check the RCIDL bit to verify that a receive operation is not in
process before setting the WUE bit. If a receive operation is not occurring, the WUE bit may then be set
just prior to entering the Sleep mode.
Figure 28-8. Auto-Wake-up Bit (WUE) Timing During Normal Operation
Rev. 10-000 326A
2/13/201 7
FOSC
q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q2 q3 q4
q1 q2 q3 q4q1
WUE bit
RXx/DTx
line
RCxIF
Bit set by user
Cleared due to user read of RCxREG
Auto cleared
Note 1: The EUSART remains in idle while the WUE bit is set.
Figure 28-9. Auto-Wake-up Bit (WUE) Timings During Sleep
Rev. 10-000 327A
2/13/201 7
FOSC
q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q2 q3 q4
q1 q2 q3 q4q1
WUE bit
RXx/DTx
line
RCxIF
Bit set by user
Cleared due to user read of RCxREG
Auto cleared
Note 1: The EUSART remains in idle while the WUE bit is set.
Sleep command executed Sleep ends
28.2.4 Break Character Sequence
The EUSART module has the capability of sending the special Break character sequences that are
required by the LIN bus standard. A Break character consists of a Start bit, followed by 12 ‘0’ bits and a
Stop bit.
To send a Break character, set the SENDB and TXEN bits of the TXxSTA register. The Break character
transmission is then initiated by a write to the TXxREG. The value of data written to TXxREG will be
ignored and all ‘0’s will be transmitted.
The SENDB bit is automatically reset by hardware after the corresponding Stop bit is sent. This allows
the user to preload the transmit FIFO with the next transmit byte following the Break character (typically,
the Sync character in the LIN specification).
The TRMT bit of the TXxSTA register indicates when the transmit operation is active or idle, just as it
does during normal transmission. See Figure 28-10 for more detail.
28.2.4.1 Break and Sync Transmit Sequence
The following sequence will start a message frame header made up of a Break, followed by an auto-baud
Sync byte. This sequence is typical of a LIN bus master.
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1. Configure the EUSART for the desired mode.
2. Set the TXEN and SENDB bits to enable the Break sequence.
3. Load the TXxREG with a dummy character to initiate transmission (the value is ignored).
4. Write ‘55h’ to TXxREG to load the Sync character into the transmit FIFO buffer.
5. After the Break has been sent, the SENDB bit is reset by hardware and the Sync character is then
transmitted.
When the TXxREG becomes empty, as indicated by the TXxIF, the next data byte can be written to
TXxREG.
28.2.5 Receiving a Break Character
The EUSART module can receive a Break character in two ways.
The first method to detect a Break character uses the FERR bit of the RCxSTA register and the received
data as indicated by RCxREG. The Baud Rate Generator is assumed to have been initialized to the
expected baud rate.
A Break character has been received when all three of the following conditions are true:
RCxIF bit is set
FERR bit is set
RCxREG = 00h
The second method uses the Auto-Wake-up feature described in 28.2.3 Auto-Wake-up on Break. By
enabling this feature, the EUSART will sample the next two transitions on RX/DT, cause an RCxIF
interrupt, and receive the next data byte followed by another interrupt.
Note that following a Break character, the user will typically want to enable the Auto-Baud Detect feature.
For both methods, the user can set the ABDEN bit of the BAUDxCON register before placing the
EUSART in Sleep mode.
Figure 28-10. Send Break Character Sequence
Rev. 10-000 118A
2/13/201 7
Write to TXxREG
BRG Output
(Shift Clock)
TXx/CKx pin
TXxIF bit
(Transmit Buffer
Reg Empty Flag)
TRMT bit
(Transmit Shift
Reg Empty Flag)
Start bit bit 0 bit 1 bit 11 Stop bit
Break
Dummy
Write
SENDB
(send break
control bit)
SENDB sampled here Auto cleared
28.3 EUSART Synchronous Mode
Synchronous serial communications are typically used in systems with a single master and one or more
slaves. The master device contains the necessary circuitry for baud rate generation and supplies the
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clock for all devices in the system. Slave devices can take advantage of the master clock by eliminating
the internal clock generation circuitry.
There are two signal lines in Synchronous mode: a bidirectional data line and a clock line. Slaves use the
external clock supplied by the master to shift the serial data into and out of their respective receive and
transmit shift registers. Since the data line is bidirectional, synchronous operation is half-duplex only. Half-
duplex refers to the fact that master and slave devices can receive and transmit data but not both
simultaneously. The EUSART can operate as either a master or slave device.
Start and Stop bits are not used in synchronous transmissions.
28.3.1 Synchronous Master Mode
The following bits are used to configure the EUSART for synchronous master operation:
SYNC = 1 (configures the EUSART for synchronous operation)
CSRC = 1 (configures the EUSART as the master)
SREN = 0 (for transmit); SREN = 1 (recommended setting to receive 1 byte)
CREN = 0 (for transmit); CREN = 1 (to receive continuously)
SPEN = 1 (enables the EUSART)
Important:  Clearing the SREN and CREN bits of the RCxSTA register ensures that the device
is in the Transmit mode, otherwise the device will be configured to receive.
28.3.1.1 Master Clock
Synchronous data transfers use a separate clock line, which is synchronous with the data. A device
configured as a master transmits the clock on the TX/CK line. The TXx/CKx pin output driver is
automatically enabled when the EUSART is configured for synchronous transmit or receive operation.
Serial data bits change on the leading edge to ensure they are valid at the trailing edge of each clock.
One clock cycle is generated for each data bit. Only as many clock cycles are generated as there are
data bits.
28.3.1.2 Clock Polarity
A clock polarity option is provided for Microwire compatibility. Clock polarity is selected with the SCKP bit
of the BAUDxCON register. Setting the SCKP bit sets the clock Idle state as high. When the SCKP bit is
set, the data changes on the falling edge of each clock. Clearing the SCKP bit sets the Idle state as low.
When the SCKP bit is cleared, the data changes on the rising edge of each clock.
28.3.1.3 Synchronous Master Transmission
Data is transferred out of the device on the RXx/DTx pin. The RXx/DTx and TXx/CKx pin output drivers
are automatically enabled when the EUSART is configured for synchronous master transmit operation.
A transmission is initiated by writing a character to the TXxREG register. If the TSR still contains all or
part of a previous character the new character data is held in the TXxREG until the last bit of the previous
character has been transmitted. If this is the first character, or the previous character has been
completely flushed from the TSR, the data in the TXxREG is immediately transferred to the TSR. The
transmission of the character commences immediately following the transfer of the data to the TSR from
the TXxREG.
Each data bit changes on the leading edge of the master clock and remains valid until the subsequent
leading clock edge.
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Note:  The TSR register is not mapped in data memory, so it is not available to the user.
28.3.1.4 Synchronous Master Transmission Setup
1. Initialize the SPxBRGH, SPxBRGL register pair and the BRG16 bit to achieve the desired baud rate
(see 28.2 EUSART Baud Rate Generator (BRG)).
2. Select the transmit output pin by writing the appropriate values to the RxyPPS register and
RXxPPS register. Both selections should enable the same pin.
3. Select the clock output pin by writing the appropriate values to the RxyPPS register and CKxPPS
register. Both selections should enable the same pin.
4. Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC.
5. Disable Receive mode by clearing bits SREN and CREN.
6. Enable Transmit mode by setting the TXEN bit.
7. If 9-bit transmission is desired, set the TX9 bit.
8. If interrupts are desired, set the TXxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
9. If 9-bit transmission is selected, the ninth bit should be loaded in the TX9D bit.
10. Start transmission by loading data to the TXxREG register.
Figure 28-11. Synchronous Transmission
Rev. 10-000 115A
2/7/201 7
Write to TXxREG
BRG Output
(Shift Clock)
TXx/CKx pin
TXxIF bit
(Transmit Buffer
Reg Empty Flag)
TRMT bit
(Transmit Shift
Reg Empty Flag)
Start bit bit 0 bit 1 bit 7/8 Stop bit
1 TCY
Word 1
Word 1
28.3.1.5 Synchronous Master Reception
Data is received at the RXx/DTx pin. The RXx/DTx pin output driver is automatically disabled when the
EUSART is configured for synchronous master receive operation.
In Synchronous mode, reception is enabled by setting either the Single Receive Enable bit (SREN of the
RCxSTA register) or the Continuous Receive Enable bit (CREN of the RCxSTA register).
When SREN is set and CREN is clear, only as many clock cycles are generated as there are data bits in
a single character. The SREN bit is automatically cleared at the completion of one character. When
CREN is set, clocks are continuously generated until CREN is cleared. If CREN is cleared in the middle of
a character the CK clock stops immediately and the partial character is discarded. If SREN and CREN
are both set, then SREN is cleared at the completion of the first character and CREN takes precedence.
To initiate reception, set either SREN or CREN. Data is sampled at the RXx/DTx pin on the trailing edge
of the TX/CK clock pin and is shifted into the Receive Shift Register (RSR). When a complete character is
received into the RSR, the RCxIF bit is set and the character is automatically transferred to the two
character receive FIFO. The Least Significant eight bits of the top character in the receive FIFO are
available in RCxREG. The RCxIF bit remains set as long as there are unread characters in the receive
FIFO.
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Note:  If the RX/DT function is on an analog pin, the corresponding ANSEL bit must be cleared for the
receiver to function.
28.3.1.6 Receive Overrun Error
The receive FIFO buffer can hold two characters. An overrun error will be generated if a third character, in
its entirety, is received before RCxREG is read to access the FIFO. When this happens the OERR bit of
the RCxSTA register is set. Previous data in the FIFO will not be overwritten. The two characters in the
FIFO buffer can be read, however, no additional characters will be received until the error is cleared. The
OERR bit can only be cleared by clearing the overrun condition. If the overrun error occurred when the
SREN bit is set and CREN is clear then the error is cleared by reading RCxREG. If the overrun occurred
when the CREN bit is set then the error condition is cleared by either clearing the CREN bit of the
RCxSTA register or by clearing the SPEN bit which resets the EUSART.
28.3.1.7 Receiving 9-Bit Characters
The EUSART supports 9-bit character reception. When the RX9 bit of the RCxSTA register is set the
EUSART will shift nine bits into the RSR for each character received. The RX9D bit of the RCxSTA
register is the ninth, and Most Significant, data bit of the top unread character in the receive FIFO. When
reading 9-bit data from the receive FIFO buffer, the RX9D data bit must be read before reading the eight
Least Significant bits from the RCxREG.
28.3.1.8 Synchronous Master Reception Setup
1. Initialize the SPxBRGH:SPxBRGL register pair and set or clear the BRG16 bit, as required, to
achieve the desired baud rate.
2. Select the receive input pin by writing the appropriate values to the RxyPPS register and RXxPPS
register. Both selections should enable the same pin.
3. Select the clock output pin by writing the appropriate values to the RxyPPS register and CKxPPS
register. Both selections should enable the same pin.
4. Clear the ANSEL bit for the RXx pin (if applicable).
5. Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC.
6. Ensure bits CREN and SREN are clear.
7. If interrupts are desired, set the RCxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
8. If 9-bit reception is desired, set bit RX9.
9. Start reception by setting the SREN bit or for continuous reception, set the CREN bit.
10. Interrupt flag bit RCxIF will be set when reception of a character is complete. An interrupt will be
generated if the enable bit RCxIE was set.
11. Read the RCxSTA register to get the ninth bit (if enabled) and determine if any error occurred
during reception.
12. Read the 8-bit received data by reading the RCxREG register.
13. If an overrun error occurs, clear the error by either clearing the CREN bit of the RCxSTA register or
by clearing the SPEN bit which resets the EUSART.
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Figure 28-12. Synchronous Reception (Master Mode, SREN)
Rev. 10-000 121A
2/13/201 7
RXx/DTx pin bit 0
TXx/CKx pin
SCKP = 0
TXx/CKx pin
SCKP = 1
bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7
Write to SREN
SREN bit
CREN bit ‘0’ ‘0’
RCxIF
(Interrupt)
Read
RCxREG
28.3.2 Synchronous Slave Mode
The following bits are used to configure the EUSART for synchronous slave operation:
SYNC = 1 (configures the EUSART for synchronous operation.)
CSRC = 0 (configures the EUSART as a slave)
SREN = 0 (for transmit); SREN = 1 (for single byte receive)
CREN = 0 (for transmit); CREN = 1 (recommended setting for continuous receive)
SPEN = 1 (enables the EUSART)
Important:  Clearing the SREN and CREN bits of the RCxSTA register ensures that the device
is in the Transmit mode, otherwise the device will be configured to receive.
28.3.2.1 Slave Clock
Synchronous data transfers use a separate clock line, which is synchronous with the data. A device
configured as a slave receives the clock on the TX/CK line. The TXx/CKx pin output driver is
automatically disabled when the device is configured for synchronous slave transmit or receive operation.
Serial data bits change on the leading edge to ensure they are valid at the trailing edge of each clock.
One data bit is transferred for each clock cycle. Only as many clock cycles should be received as there
are data bits.
Important:  If the device is configured as a slave and the TX/CK function is on an analog pin,
the corresponding ANSEL bit must be cleared.
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28.3.2.2 EUSART Synchronous Slave Transmit
The operation of the Synchronous Master and Slave modes are identical (see 28.3.1.3 Synchronous
Master Transmission), except in the case of the Sleep mode.
If two words are written to the TXxREG and then the SLEEP instruction is executed, the following will
occur:
1. The first character will immediately transfer to the TSR register and transmit.
2. The second word will remain in the TXxREG register.
3. The TXxIF bit will not be set.
4. After the first character has been shifted out of TSR, the TXxREG register will transfer the second
character to the TSR and the TXxIF bit will now be set.
5. If the PEIE and TXxIE bits are set, the interrupt will wake the device from Sleep and execute the
next instruction. If the GIE bit is also set, the program will call the Interrupt Service Routine.
28.3.2.3 Synchronous Slave Transmission Setup
1. Set the SYNC and SPEN bits and clear the CSRC bit.
2. Select the transmit output pin by writing the appropriate values to the RxyPPS register and
RXxPPS register. Both selections should enable the same pin.
3. Select the clock input pin by writing the appropriate value to the CKxPPS register.
4. Clear the ANSEL bit for the CKx pin (if applicable).
5. Clear the CREN and SREN bits.
6. If interrupts are desired, set the TXxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
7. If 9-bit transmission is desired, set the TX9 bit.
8. Enable transmission by setting the TXEN bit.
9. If 9-bit transmission is selected, insert the Most Significant bit into the TX9D bit.
10. Prepare for transmission by writing the Least Significant eight bits to the TXxREG register. The
word will be transmitted in response to the Master clocks at the CKx pin.
28.3.2.4 EUSART Synchronous Slave Reception
The operation of the Synchronous Master and Slave modes is identical (see 28.3.1.5 Synchronous
Master Reception), with the following exceptions:
Sleep
CREN bit is always set, therefore the receiver is never idle
SREN bit, which is a “don’t care” in Slave mode
A character may be received while in Sleep mode by setting the CREN bit prior to entering Sleep. Once
the word is received, the RSR register will transfer the data to the RCxREG register. If the RCxIE enable
bit is set, the interrupt generated will wake the device from Sleep and execute the next instruction. If the
GIE bit is also set, the program will branch to the interrupt vector.
28.3.2.5 Synchronous Slave Reception Setup:
1. Set the SYNC and SPEN bits and clear the CSRC bit.
2. Select the receive input pin by writing the appropriate value to the RXxPPS register.
3. Select the clock input pin by writing the appropriate values to the CKxPPS register.
4. Clear the ANSEL bit for both the TXx/CKx and RXx/DTx pins (if applicable).
5. If interrupts are desired, set the RCxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
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6. If 9-bit reception is desired, set the RX9 bit.
7. Set the CREN bit to enable reception.
8. The RCxIF bit will be set when reception is complete. An interrupt will be generated if the RCxIE bit
was set.
9. If 9-bit mode is enabled, retrieve the Most Significant bit from the RX9D bit of the RCxSTA register.
10. Retrieve the eight Least Significant bits from the receive FIFO by reading the RCxREG register.
11. If an overrun error occurs, clear the error by either clearing the CREN bit of the RCxSTA register or
by clearing the SPEN bit which resets the EUSART.
28.4 EUSART Operation During Sleep
The EUSART will remain active during Sleep only in the Synchronous Slave mode. All other modes
require the system clock and therefore cannot generate the necessary signals to run the Transmit or
Receive Shift registers during Sleep.
Synchronous Slave mode uses an externally generated clock to run the Transmit and Receive Shift
registers.
28.4.1 Synchronous Receive During Sleep
To receive during Sleep, all the following conditions must be met before entering Sleep mode:
RCxSTA and TXxSTA Control registers must be configured for Synchronous Slave Reception (see
28.3.2.5 Synchronous Slave Reception Setup:).
If interrupts are desired, set the RCxIE bit of the PIEx register and the GIE and PEIE bits of the
INTCON register.
The RCxIF interrupt flag must be cleared by reading RCxREG to unload any pending characters in
the receive buffer.
Upon entering Sleep mode, the device will be ready to accept data and clocks on the RXx/DTx and
TXx/CKx pins, respectively. When the data word has been completely clocked in by the external device,
the RCxIF interrupt flag bit of the PIRx register will be set. Thereby, waking the processor from Sleep.
Upon waking from Sleep, the instruction following the SLEEP instruction will be executed. If the Global
Interrupt Enable (GIE) bit of the INTCON register is also set, then the Interrupt Service Routine at
address 004h will be called.
28.4.2 Synchronous Transmit During Sleep
To transmit during Sleep, all the following conditions must be met before entering Sleep mode:
The RCxSTA and TXxSTA Control registers must be configured for synchronous slave transmission
(see 28.3.2.3 Synchronous Slave Transmission Setup).
The TXxIF interrupt flag must be cleared by writing the output data to the TXxREG, thereby filling the
TSR and transmit buffer.
Interrupt enable bits TXxIE of the PIEx register and PEIE of the INTCON register must set.
If interrupts are desired, set the GIEx bit of the INTCON register.
Upon entering Sleep mode, the device will be ready to accept clocks on the TXx/CKx pin and transmit
data on the RXx/DTx pin. When the data word in the TSR has been completely clocked out by the
external device, the pending byte in the TXxREG will transfer to the TSR and the TXxIF flag will be set.
Thereby, waking the processor from Sleep. At this point, the TXxREG is available to accept another
character for transmission. Writing TXxREG will clear the TXxIF flag.
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Upon waking from Sleep, the instruction following the SLEEP instruction will be executed. If the Global
Interrupt Enable (GIE) bit is also set then the Interrupt Service Routine at address 0004h will be called.
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28.5 Register Summary - EUSART
Address Name Bit Pos.
0x0E94 RC2REG 7:0 RCREG[7:0]
0x0E95 TX2REG 7:0 TXREG[7:0]
0x0E96 SP2BRG
7:0 SPBRGL[7:0]
15:8 SPBRGH[7:0]
0x0E98 RC2STA 7:0 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
0x0E99 TX2STA 7:0 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
0x0E9A BAUD2CON 7:0 ABDOVF RCIDL SCKP BRG16 WUE ABDEN
0x0E9B
...
0x0F97
Reserved
0x0F98 RC1REG 7:0 RCREG[7:0]
0x0F99 TX1REG 7:0 TXREG[7:0]
0x0F9A SP1BRG
7:0 SPBRGL[7:0]
15:8 SPBRGH[7:0]
0x0F9C RC1STA 7:0 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
0x0F9D TX1STA 7:0 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
0x0F9E BAUD1CON 7:0 ABDOVF RCIDL SCKP BRG16 WUE ABDEN
28.6 Register Definitions: EUSART Control
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28.6.1 RCxSTA
Name:  RCxSTA
Address:  0xF9C,0xE98
Receive Status and Control Register
Bit 7 6 5 4 3 2 1 0
SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
Access R/W R/W R/W R/W R/W RO R/HC R/HC
Reset 0 0 0 0 0 0 0 0
Bit 7 – SPEN Serial Port Enable bit
Value Description
1Serial port enabled
0Serial port disabled (held in Reset)
Bit 6 – RX9 9-Bit Receive Enable bit
Value Description
1Selects 9-bit reception
0Selects 8-bit reception
Bit 5 – SREN Single Receive Enable bit
Controls reception. This bit is cleared by hardware when reception is complete
Value Condition Description
1SYNC = 1 AND CSRC = 1Start single receive
0SYNC = 1 AND CSRC = 1Single receive is complete
XSYNC = 0 OR CSRC = 0Don't care
Bit 4 – CREN Continuous Receive Enable bit
Value Condition Description
1SYNC = 1Enables continuous receive until enable bit CREN is cleared (CREN overrides
SREN)
0SYNC = 1Disables continuous receive
1SYNC = 0Enables receiver
0SYNC = 0Disables receiver
Bit 3 – ADDEN Address Detect Enable bit
Value Condition Description
1SYNC = 0 AND RX9 = 1The receive buffer is loaded and the interrupt occurs only when the
ninth received bit is set
0SYNC = 0 AND RX9 = 1All bytes are received and interrupt always occurs. Ninth bit can be
used as parity bit
XRX9 = 0 OR SYNC = 1Don't care
Bit 2 – FERR Framing Error bit
Value Description
1Unread byte in 28.6.5 RCxREG has a framing error
0Unread byte in 28.6.5 RCxREG does not have a framing error
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Bit 1 – OERR Overrun Error bit
Value Description
1Overrun error (can be cleared by clearing either SPEN or CREN bit)
0No overrun error
Bit 0 – RX9D Ninth bit of Received Data
This can be address/data bit or a parity bit which is determined by user firmware.
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28.6.2 TXxSTA
Name:  TXxSTA
Address:  0xF9D,0xE99
Transmit Status and Control Register
Bit 7 6 5 4 3 2 1 0
CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
Access R/W R/W R/W R/W R/W R/W RO R/W
Reset 0 0 0 0 0 0 1 0
Bit 7 – CSRC Clock Source Select bit
Value Condition Description
1SYNC= 1Master mode (clock generated internally from BRG)
0SYNC= 1Slave mode (clock from external source)
XSYNC= 0Don't care
Bit 6 – TX9 9-bit Transmit Enable bit
Value Description
1Selects 9-bit transmission
0Selects 8-bit transmission
Bit 5 – TXEN Transmit Enable bit
Enables transmitter(1)
Value Description
1Transmit enabled
0Transmit disabled
Bit 4 – SYNC EUSART Mode Select bit
Value Description
1Synchronous mode
0Asynchronous mode
Bit 3 – SENDB Send Break Character bit
Value Condition Description
1SYNC= 0Send Sync Break on next transmission (cleared by hardware upon completion)
0SYNC= 0Sync Break transmission disabled or completed
XSYNC= 1Don't care
Bit 2 – BRGH High Baud Rate Select bit
Value Condition Description
1SYNC= 0High speed, if BRG16 = 1, baud rate is baudclk/4; else baudclk/16
0SYNC= 0Low speed
XSYNC= 1Don't care
Bit 1 – TRMT Transmit Shift Register (TSR) Status bit
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Value Description
1TSR is empty
0TSR is not empty
Bit 0 – TX9D Ninth bit of Transmit Data
Can be address/data bit or a parity bit.
Note: 
1. SREN and CREN bits override TXEN in Sync mode.
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28.6.3 BAUDxCON
Name:  BAUDxCON
Address:  0xF9E,0xE9A
Baud Rate Control Register
Bit 7 6 5 4 3 2 1 0
ABDOVF RCIDL SCKP BRG16 WUE ABDEN
Access RO RO RW RW RW RW
Reset 0 0 0 0 0 0
Bit 7 – ABDOVF Auto-Baud Detect Overflow bit
Value Condition Description
1SYNC= 0Auto-baud timer overflowed
0SYNC= 0Auto-baud timer did not overflow
XSYNC= 1Don't care
Bit 6 – RCIDL Receive Idle Flag bit
Value Condition Description
1SYNC= 0Receiver is Idle
0SYNC= 0Start bit has been received and the receiver is receiving
XSYNC= 1Don't care
Bit 4 – SCKP Synchronous Clock Polarity Select bit
Value Condition Description
1SYNC= 0Idle state for transmit (TX) is a low level (transmit data inverted)
0SYNC= 0Idle state for transmit (TX) is a high level (transmit data is non-inverted)
1SYNC= 1Data is clocked on rising edge of the clock
0SYNC= 1Data is clocked on falling edge of the clock
Bit 3 – BRG16 16-bit Baud Rate Generator Select bit
Value Description
116-bit Baud Rate Generator is used
08-bit Baud Rate Generator is used
Bit 1 – WUE Wake-up Enable bit
Value Condition Description
1SYNC= 0Receiver is waiting for a falling edge. Upon falling edge no character will be
received and flag RCxIF will be set. WUE will automatically clear after RCxIF is
set.
0SYNC= 0Receiver is operating normally
XSYNC= 1Don't care
Bit 0 – ABDEN Auto-Baud Detect Enable bit
Value Condition Description
1SYNC= 0Auto-Baud Detect mode is enabled (clears when auto-baud is complete)
0SYNC= 0Auto-Baud Detect is complete or mode is disabled
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Value Condition Description
XSYNC= 1Don't care
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28.6.4 SPxBRG
Name:  SPxBRG
Address:  0xF9A,0xE96
Baud Rate Determination Register
Bit 15 14 13 12 11 10 9 8
SPBRGH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
SPBRGL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – SPBRGH[7:0] Baud Rate High Byte Register
Bits 7:0 – SPBRGL[7:0] Baud Rate Low Byte Register
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28.6.5 RCxREG
Name:  RCxREG
Address:  0xF98,0xE94
Receive Data Register
Bit 7 6 5 4 3 2 1 0
RCREG[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – RCREG[7:0] Receive data
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28.6.6 TXxREG
Name:  TXxREG
Address:  0xF99,0xE95
Transmit Data Register
Bit 7 6 5 4 3 2 1 0
TXREG[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – TXREG[7:0] Transmit Data
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29. (FVR) Fixed Voltage Reference
The Fixed Voltage Reference (FVR) is a stable voltage reference, independent of VDD, with the following
selectable output levels:
1.024V
2.048V
4.096V
The output of the FVR can be configured to supply a reference voltage to the following:
ADC input channel
ADC positive reference
Comparator input
Digital-to-Analog Converter (DAC)
The FVR can be enabled by setting the FVREN bit of the FVRCON register.
Important:  Fixed Voltage Reference output cannot exceed VDD.
29.1 Independent Gain Amplifiers
The output of the FVR, which is connected to the ADC, Comparators, and DAC, is routed through two
independent programmable gain amplifiers. Each amplifier can be programmed for a gain of 1x, 2x or 4x,
to produce the three possible voltage levels.
The ADFVR<1:0> bits of the FVRCON register are used to enable and configure the gain amplifier
settings for the reference supplied to the ADC module. Reference the ADC chapter for additional
information.
The CDAFVR<1:0> bits of the FVRCON register are used to enable and configure the gain amplifier
settings for the reference supplied to the DAC and comparator module.
Related Links
32. (ADC2) Analog-to-Digital Converter with Computation Module
33. (CMP) Comparator Module
31. (DAC) 5-Bit Digital-to-Analog Converter Module
29.2 FVR Stabilization Period
When the Fixed Voltage Reference module is enabled, it requires time for the reference and amplifier
circuits to stabilize. Once the circuits stabilize and are ready for use, the FVRRDY bit of the FVRCON
register will be set.
PIC18F26/45/46Q10
(FVR) Fixed Voltage Reference
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 568
Figure 29-1. Voltage Reference Block Diagram
Filename: 10-000053C.vsd
Title: VOLTAGE REFERENCE BLOCK DIAGRAM (ADC, Comp and DAC)
Last Edit: 12/9/2013
First Used: PIC16F1613 (LECQ)
Note: Any peripheral requiring the Fixed Reference (See Table 13-1)
1x
2x
4x
1x
2x
4x
ADFVR<1:0>
CDAFVR<1:0>
FVR_buffer1
(To ADC Module)
FVR_buffer2
(To Comparators
and DAC)
+
_
FVREN FVRRDY
Note 1
2
2
Rev. 10-000 053C
12/9/201 3
Note: 
1. Any peripheral requiring the FVR
PIC18F26/45/46Q10
(FVR) Fixed Voltage Reference
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 569
29.3 Register Summary - FVR
Address Name Bit Pos.
0x0F2C FVRCON 7:0 FVREN FVRRDY TSEN TSRNG CDAFVR[1:0] ADFVR[1:0]
29.4 Register Definitions: FVR Control
PIC18F26/45/46Q10
(FVR) Fixed Voltage Reference
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 570
29.4.1 FVRCON
Name:  FVRCON
Address:  0xF2C
Fixed Voltage Reference Control Register
Bit 7 6 5 4 3 2 1 0
FVREN FVRRDY TSEN TSRNG CDAFVR[1:0] ADFVR[1:0]
Access R/W R R/W R/W R/W R/W R/W R/W
Reset 0 q 0 0 0 0 0 0
Bit 7 – FVREN Fixed Voltage Reference Enable bit
Value Description
1Fixed Voltage Reference is enabled
0Fixed Voltage Reference is disabled
Bit 6 – FVRRDY Fixed Voltage Reference Ready Flag bit
Value Description
1Fixed Voltage Reference output is ready for use
0Fixed Voltage Reference output is not ready or not enabled
Bit 5 – TSEN
Temperature Indicator Enable bit(2)
Value Description
1Temperature Indicator is enabled
0Temperature Indicator is disabled
Bit 4 – TSRNG
Temperature Indicator Range Selection bit(2)
Value Description
1VOUT = VDD - 4Vt (High Range)
0VOUT = VDD - 2Vt (Low Range)
Bits 3:2 – CDAFVR[1:0] Comparator FVR Buffer Gain Selection bits
Value Description
11 Comparator FVR Buffer Gain is 4x, (4.096V)(1)
10 Comparator FVR Buffer Gain is 2x, (2.048V)(1)
01 Comparator FVR Buffer Gain is 1x, (1.024V)
00 Comparator FVR Buffer is off
Bits 1:0 – ADFVR[1:0] ADC FVR Buffer Gain Selection bit
Value Description
11 ADC FVR Buffer Gain is 4x, (4.096V)(1)
10 ADC FVR Buffer Gain is 2x, (2.048V)(1)
01 ADC FVR Buffer Gain is 1x, (1.024V)
00 ADC FVR Buffer is off
PIC18F26/45/46Q10
(FVR) Fixed Voltage Reference
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 571
Note: 
1. Fixed Voltage Reference output cannot exceed VDD.
2. See Temperature Indicator Module section for additional information.
Related Links
30. Temperature Indicator Module
PIC18F26/45/46Q10
(FVR) Fixed Voltage Reference
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 572
30. Temperature Indicator Module
This family of devices is equipped with a temperature circuit designed to measure the operating
temperature of the silicon die. The circuit’s range of operating temperature falls between -40°C and
+85°C. The output is a voltage that is proportional to the device temperature. The output of the
temperature indicator is internally connected to the device ADC.
The circuit may be used as a temperature threshold detector or a more accurate temperature indicator,
depending on the level of calibration performed. A one-point calibration allows the circuit to indicate a
temperature closely surrounding that point. A two-point calibration allows the circuit to sense the entire
range of temperature more accurately. Refer to Application Note AN1333, “Use and Calibration of the
Internal Temperature Indicator” (DS00001333) for more details regarding the calibration process.
30.1 Circuit Operation
Figure 30-2 shows a simplified block diagram of the temperature circuit. The proportional voltage output
is achieved by measuring the forward voltage drop across multiple silicon junctions.
The following equation describes the output characteristics of the temperature indicator.
Figure 30-1. VOUT Ranges
: = 4 : = 2
The temperature sense circuit is integrated with the Fixed Voltage Reference (FVR) module. See “Fixed
Voltage Reference (FVR)” chapter for more information.
The circuit is enabled by setting the TSEN bit of the FVRCON register. When disabled, the circuit draws
no current.
The circuit operates in either high or low range. The high range, selected by setting the TSRNG bit of the
FVRCON register, provides a wider output voltage. This provides more resolution over the temperature
range, but may be less consistent from part to part. This range requires a higher bias voltage to operate
and thus, a higher VDD is needed.
The low range is selected by clearing the TSRNG bit of the FVRCON register. The low range generates a
lower voltage drop and thus, a lower bias voltage is needed to operate the circuit. The low range is
provided for low voltage operation.
PIC18F26/45/46Q10
Temperature Indicator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 573
Figure 30-2. Temperature Circuit Diagram
VOUT
Temp. Indicator To ADC
TSRNG
TSEN
Rev. 10-000069A
7/31/2013
VDD
Related Links
29. (FVR) Fixed Voltage Reference
30.2 Minimum Operating VDD
When the temperature circuit is operated in low range, the device may be operated at any operating
voltage that is within specifications.
When the temperature circuit is operated in high range, the device operating voltage, VDD, must be high
enough to ensure that the temperature circuit is correctly biased.
Table 30-1 shows the recommended minimum VDD vs. range setting.
Table 30-1. Recommended VDD vs. Range
Min. VDD, TSRNG = 1Min. VDD, TSRNG = 0
3.6V 1.8V
30.3 Temperature Output
The output of the circuit is measured using the internal Analog-to-Digital Converter. A channel is reserved
for the temperature circuit output. Refer to “Analog-to-Digital Converter with Computation (ADC2) Module”
chapter for detailed information.
Related Links
32. (ADC2) Analog-to-Digital Converter with Computation Module
PIC18F26/45/46Q10
Temperature Indicator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 574
30.4 ADC Acquisition Time
To ensure accurate temperature measurements, the user must wait at least 200 μs after the ADC input
multiplexer is connected to the temperature indicator output before the conversion is performed. In
addition, the user must wait 200 μs between consecutive conversions of the temperature indicator output.
PIC18F26/45/46Q10
Temperature Indicator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 575
31. (DAC) 5-Bit Digital-to-Analog Converter Module
The Digital-to-Analog Converter supplies a variable voltage reference, ratiometric with the input source,
with 32 selectable output levels.
The positive input source (VSOURCE+) of the DAC can be connected to:
FVR Buffer
External VREF+ pin
VDD supply voltage
The negative input source (VSOURCE-) of the DAC can be connected to:
External VREF- pin
VSS
The output of the DAC (DACx_output) can be selected as a reference voltage to the following:
Comparator positive input
ADC input channel
DACxOUT1 pin
DACxOUT2 pin
The Digital-to-Analog Converter (DAC) can be enabled by setting the EN bit.
PIC18F26/45/46Q10
(DAC) 5-Bit Digital-to-Analog Converter Modu...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 576
Figure 31-1. Digital-to-Analog Converter Block Diagram
Filename: 10-000026F.vsd
Title: 5bit_DAC Block Diagram
Last Edit: 8/7/2015
First Used: PIC16(L)F1508/9 (LECD)
Note 1: The unbuffered DACx_output is provided on the DACxOUT pin(s).
VREF+
AVDD
DACPSS
VSOURCE+
VSOURCE-
AVSS
R
32
Steps
R
R
R
R
R
R
32-to-1 MUX
To Peripherals
DACxOUT1(1)
DACOE1
DACx_output
DACEN
DACR<4:0>
5
DACxOUT2(1)
DACOE2
Rev. 10-000026F
8/7/2015
00
11
10
01
FVR Buffer
Reserved
1
0
VREF-
DACNSS
Note: 
1. The unbuffered DACx_output is provided on the DACxOUT pin(s).
31.1 Output Voltage Selection
The DAC has 32 voltage level ranges. The 32 levels are set with the DAC1R bits.
The DAC output voltage can be determined by using the following equation.
Figure 31-2. DAC Output Voltage
When EN = 1:
_ = +   4: 0
25+
Note:  See the DAC1CON0 register for the available VSOURCE+ and VSOURCE- selections.
PIC18F26/45/46Q10
(DAC) 5-Bit Digital-to-Analog Converter Modu...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 577
31.2 Ratiometric Output Level
The DAC output value is derived using a resistor ladder with each end of the ladder tied to a positive and
negative voltage reference input source. If the voltage of either input source fluctuates, a similar
fluctuation will result in the DAC output value.
The value of the individual resistors within the ladder can be found in the “5-Bit DAC Specifications” table
from the “Electrical Specifications” chapter.
Related Links
39.4.10 5-Bit DAC Specifications
31.3 DAC Voltage Reference Output
The unbuffered DAC voltage can be output to the DACxOUTn pin(s) by setting the respective OEn bit(s).
Selecting the DAC reference voltage for output on either DACxOUTn pin automatically overrides the
digital output buffer, the weak pull-up and digital input threshold detector functions of that pin.
Reading the DACxOUTn pin when it has been configured for DAC reference voltage output will always
return a ‘0’.
Important:  The unbuffered DAC output (DACxOUTn) is not intended to drive an external load.
31.4 Operation During Sleep
When the device wakes up from Sleep through an interrupt or a Windowed Watchdog Timer Time-out, the
contents of the DACxCON0 register are not affected. To minimize current consumption in Sleep mode,
the voltage reference should be disabled.
31.5 Effects of a Reset
A device Reset affects the following:
DACx is disabled.
DACx output voltage is removed from the DACxOUTn pin(s).
The DAC1R range select bits are cleared.
PIC18F26/45/46Q10
(DAC) 5-Bit Digital-to-Analog Converter Modu...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 578
31.6 Register Summary - DAC Control
Address Name Bit Pos.
0x0F2E DAC1CON0 7:0 EN OE1 OE2 PSS[1:0] NSS
0x0F2F DAC1CON1 7:0 DAC1R[4:0]
31.7 Register Definitions: DAC Control
Long bit name prefixes for the DAC are shown in the table below. Refer to the "Long Bit Names Section"
for more information.
Table 31-1.  DAC Long Bit Name Prefixes
Peripheral Bit Name Prefix
DAC DAC
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
(DAC) 5-Bit Digital-to-Analog Converter Modu...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 579
31.7.1 DAC1CON0
Name:  DAC1CON0
Address:  0xF2E
DAC Control Register
Bit 7 6 5 4 3 2 1 0
EN OE1 OE2 PSS[1:0] NSS
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bit 7 – EN DAC Enable bit
Value Description
1DAC is enabled
0DAC is disabled
Bit 5 – OE1 DAC Voltage Output Enable bit
Value Description
1DAC voltage level is output on the DAC1OUT1 pin
0DAC voltage level is disconnected from the DAC1OUT1 pin
Bit 4 – OE2 DAC Voltage Output Enable bit
Value Description
1DAC voltage level is output on the DAC1OUT2 pin
0DAC voltage level is disconnected from the DAC1OUT2 pin
Bits 3:2 – PSS[1:0] DAC Positive Source Select bit
Value Description
11 Reserved
10 FVR buffer
01 VREF+
00 AVDD
Bit 0 – NSS DAC Negative Source Select bit
Value Description
1VREF-
0AVSS
PIC18F26/45/46Q10
(DAC) 5-Bit Digital-to-Analog Converter Modu...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 580
31.7.2 DAC1CON1
Name:  DAC1CON1
Address:  0xF2F
DAC Data Register
Bit 7 6 5 4 3 2 1 0
DAC1R[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – DAC1R[4:0] Data Input Register for DAC bits
PIC18F26/45/46Q10
(DAC) 5-Bit Digital-to-Analog Converter Modu...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 581
32. (ADC2) Analog-to-Digital Converter with Computation Module
The Analog-to-Digital Converter with Computation (ADC2) allows conversion of an analog input signal to
a 10-bit binary representation of that signal. This device uses analog inputs that are multiplexed into a
single Sample-and-Hold circuit. The output of the Sample-and-Hold is connected to the input of the
converter. The converter generates a 10-bit binary result via successive approximation and stores the
conversion result into the ADC result registers (32.7.15 ADRES).
Additionally, the following features are provided within the ADC module:
8-bit Acquisition Timer
Hardware Capacitive Voltage Divider (CVD) support:
8-bit precharge timer
Adjustable Sample-and-Hold capacitor array
Guard ring digital output drive
Automatic Repeat and Sequencing:
Automated double sample conversion for CVD
Two sets of Result registers (Result and Previous Result)
Auto-conversion trigger
Internal retrigger
Computation Features:
Averaging and low-pass filter functions
Reference comparison
2-level threshold comparison
Selectable interrupts
Figure 32-1 shows the block diagram of the ADC.
The ADC voltage reference is software selectable to be either internally generated or externally supplied.
The ADC can generate an interrupt upon completion of a conversion and upon threshold comparison.
These interrupts can be used to wake-up the device from Sleep.
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 582
Figure 32-1. ADC2 Block Diagram
Filename: 10-000034C.vsd
Title: 10-Bit ADC Block Diagram
Last Edit: 5/10/2016
First Used: PIC16(L)F188X5 (MFAF)
Vref+Vref-
Enable
DACx_output
FVR_buffer1
Temp Indicator
CHS<x:0>
External
Channel
Inputs
GO/DONE
complete
start
ADC
Sample Circuit
Write to bit
GO/DONE
VSS
VDD
VREF+ pin
ADPREF<1:0>
10-bit Result
ADRESH ADRESL
16
ADFM
10
Internal
Channel
Inputs
.
.
.
AN0
ANa
ANz
set bit ADIF
VSS
ADON
sampled
input
Q1
Q2
Q4
Fosc
Divider FOSC
FOSC/n
FRC
ADC
Clock
Select
ADC_clk
ADCS<2:0>
FRC
ADC CLOCK SOURCE
Trigger Select
Trigger Sources
. . .
TRIGSEL<x:0>
AUTO CONVERSION
TRIGGER
Rev. 10-000034C
5/10/2016
Positive
Reference
Select
00
11
10
01Reserved
FVR_buffer1
1
0
ADNREF
VREF- pin
VSS
To Computation
module
32.1 ADC Configuration
When configuring and using the ADC the following functions must be considered:
Port Configuration
Channel Selection
ADC Voltage Reference Selection
ADC Conversion Clock Source
Interrupt Control
Result Formatting
Conversion Trigger Selection
ADC Acquisition Time
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 583
ADC Precharge Time
Additional Sample-and-Hold Capacitor
Single/Double Sample Conversion
Guard Ring Outputs
32.1.1 Port Configuration
The ADC can be used to convert both analog and digital signals. When converting analog signals, the I/O
pin should be configured for analog by setting the associated TRIS and ANSEL bits. Refer to the "I/O
Ports" section for more information.
Important:  Analog voltages on any pin that is defined as a digital input may cause the input
buffer to conduct excess current.
Related Links
15. I/O Ports
32.1.2 Channel Selection
The 32.7.8 ADPCH register determines which channel is connected to the Sample-and-Hold circuit.
There are several channel selections available as shown in the following selection table:
Table 32-1. ADC Positive Input Channel Selections
ADPCH ADC Positive Channel Input
111111 Fixed Voltage Reference (FVR)(2)
111110 DAC1 output(1)
111101 Temperature Indicator(3)
111100 AVSS (Analog Ground)
100011-111011 Reserved. No channel connected.
100010 RE2/ANE2(1)
100001 RE1/ANE1(1)
100000 RE0/ANE0(1)
011111 RD7/AND7(1)
011110 RD6/AND6(1)
011101 RD5/AND5(1)
011100 RD4/AND4(1)
011011 RD3/AND3(1)
011010 RD2/AND2(1)
011001 RD1/AND1(1)
011000 RD0/AND0(1)
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 584
...........continued
ADPCH ADC Positive Channel Input
010111 RC7/ANC7
010110 RC6/ANC6
010101 RC5/ ANC5
010100 RC4/ ANC4
010011 RC3/ANC3
010010 RC2/ANC2
010001 RC1/ ANC1
010000 RC0/ANC0
001111 RB7/ANB7
001110 RB6/ANB6
001101 RB5/ANB5
001100 RB4/ ANB4
001011 RB3/ANB3
001010 RB2/ ANB2
001001 RB1/ ANB1
001000 RB0/ANB0
000111 RA7/ANA7
000110 RA6/ANA6
000101 RA5/ANA5
000100 RA4/ ANA4
000011 RA3/ ANA3
000010 RA2/ ANA2
000001 RA1/ ANA1
000000 RA0/ANA0
Note: 
1. 40/44-pin devices only.
When changing channels, a delay is required before starting the next conversion.
Refer to Section “ADC Operation” for more information.
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 585
Important:  It is recommended to discharge the Sample-and-Hold capacitor when switching
between ADC channels by starting a conversion on a channel connected to VSS and terminating
the conversion after the acquisition time has elapsed. If the ADC does not have a dedicated VSS
input channel, the VSS selection (DAC1R<4:0> = b'00000') through the DAC output channel can
be used. If the DAC is in use, a free input channel can be connected to VSS, and can be used in
place of the DAC.
32.1.3 ADC Voltage Reference
The ADPREF bits provide control of the positive voltage reference. The positive voltage reference can be:
VREF+ pin
VDD
FVR 1.024V
FVR 2.048V
FVR 4.096V
The ADNREF bit provides control of the negative voltage reference. The negative voltage reference can
be:
VREF- pin
VSS
32.1.4 Conversion Clock
The conversion clock source is software selected with the ADCS bit. When ADCS = 1 the ADC clock
source is an internal fixed-frequency clock referred to as FRC. When ADCS = 0 the ADC clock
frequencies are derived from FOSC. The 32.7.6 ADCLK register selects one of 64 possible clock options
from FOSC/2 to FOSC/128:
FOSC/2
FOSC/4
FOSC/6
FOSC/8
FOSC/10
...
FOSC/128
The time to complete one bit conversion is defined as the TAD. One full 10-bit conversion requires 11.5
TAD periods as shown in Figure 32-2.
For correct conversion, the appropriate TAD specification must be met. Refer to the "ADC Timing
Specifications" for more information. The "ADC Clock Period" table below gives examples of appropriate
ADC clock selections.
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 586
Important: 
1. Except for the FRC clock source, any changes in the system clock frequency will change
the ADC clock frequency, which may adversely affect the ADC result.
2. The internal control logic of the ADC runs off of the clock selected by ADCS. When the
ADCS is set to ‘1’ (ADC runs on FRC), there may be unexpected delays in operation
when setting ADC control bits.
Table 32-2. ADC Clock Period (TAD) Vs. Device Operating Frequencies(1,4)
ADC Clock Period
(TAD)Device Frequency (FOSC)
ADC
Clock
Source
ADCLK 64 MHz 32 MHz 20 MHz 16 MHz 8 MHz 4 MHz 1 MHz
FOSC/2 000000 31.25
ns(2)
62.5 ns(2) 100 ns(2) 125 ns(2) 250 ns(2) 500 ns(2) 2.0 μs
FOSC/4 000001 62.5 ns(2) 125 ns(2) 200 ns(2) 250 ns(2) 500 ns(2) 1.0 μs 4.0 μs
FOSC/6 000010 125 ns(2) 187.5
ns(2)
300 ns(2) 375 ns(2) 750 ns(2) 1.5 μs 6.0 μs
FOSC/8 000011 187.5
ns(2)
250 ns(2) 400 ns(2) 500 ns(2) 1.0 μs 2.0 μs 8.0 μs(3)
... ... ... ... ... ... ... ... ...
FOSC/16 000111 250 ns(2) 500 ns(2) 800 ns(2) 1.0 μs 2.0 μs 4.0 μs 16.0 μs(3)
... ... ... ... ... ... ... ... ...
FOSC/128 111111 2.0 μs 4.0 μs 6.4 μs 8.0 μs 16.0 μs(3) 32.0 μs(2) 128.0
μs(2)
FRC ADCS=11.0-6.0
μs
1.0-6.0
μs
1.0-6.0
μs
1.0-6.0
μs
1.0-6.0
μs
1.0-6.0
μs
1.0-6.0
μs
Note: 
1. See TAD parameter in the "Electrical Specifications" section for FRC source typical TAD value.
2. These values violate the required TAD time.
3. Outside the recommended TAD time.
4. The ADC clock period (TAD) and total ADC conversion time can be minimized when the ADC
clock is derived from the system clock FOSC. However, the FRC oscillator source must be used
when conversions are to be performed with the device in Sleep mode.
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
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Figure 32-2. Analog-to-Digital Conversion TAD Cycles
On the following cycle:
ADRESH:ADRESL is loaded,
GO bit is cleared,
ADIF bit is set,
Rev. 10-000035B
11/3/2016
Set GO bit
External and Internal
Channels are
charged/discharged
If ADPRE 0If ADACQ 0
External and Internal
Channels share
charge
If ADPRE = 0
If ADACQ = 0
(Traditional Operation Start)
TAD1
TCY TCY-TAD TAD2TAD3TAD4TAD5TAD6TAD7TAD8TAD9TAD10TAD11
Holding capacitor CHOLD is disconnected from analog input (typically 100ns)
2 TCY
Conversion starts
b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Precharge
Time
1-255 TCY
(TPRE)
Acquisition/
Sharing Time
1-255 TCY
(TACQ)
Conversion Time
(Traditional Timing of ADC Conversion)
Related Links
39.4.8 Analog-to-Digital Converter (ADC) Conversion Timing Specifications
32.1.5 Interrupts
The ADC module allows for the ability to generate an interrupt upon completion of an Analog-to-Digital
Conversion. The ADC Interrupt Flag is the ADIF bit in the PIRx register. The ADC Interrupt Enable is the
ADIE bit in the PIEx register. The ADIF bit must be cleared in software.
Important: 
1. The ADIF bit is set at the completion of every conversion, regardless of whether or not the
ADC interrupt is enabled.
2. The ADC operates during Sleep only when the FRC oscillator is selected.
This interrupt can be generated while the device is operating or while in Sleep. If the device is in Sleep,
the interrupt will wake-up the device. Upon waking from Sleep, the next instruction following the SLEEP
instruction is always executed. If the user is attempting to wake-up from Sleep and resume in-line code
execution, the ADIE bit and the PEIE bit of the INTCON register must both be set and the GIE bit of the
INTCON register must be cleared. If all three of these bits are set, the execution will switch to the
Interrupt Service Routine.
32.1.6 Result Formatting
The 10-bit ADC conversion result can be supplied in two formats, left justified or right justified. The ADFM
bit controls the output format as shown in the following figure.
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Figure 32-3. 10-Bit ADC Conversion Result Format
ADRESH ADRESL
(ADFM = 0) MSB LSB
bit 7 bit 0 bit 7 bit 0
10-bit ADC Result Unimplemented: Read as ‘0
(ADFM = 1)MSB LSB
bit 7 bit 0 bit 7 bit 0
Unimplemented: Read as ‘0 10-bit ADC Result
Rev. 30-000116A
5/16/2017
32.2 ADC Operation
32.2.1 Starting a Conversion
To enable the ADC module, the ADON must be set to a ‘1’. A conversion may be started by any of the
following:
Software setting the ADGO bit to '1'
An external trigger (source selected by 32.7.22 ADACT)
A continuous-mode retrigger (see section 32.5.8 Continuous Sampling Mode)
.
Important:  The ADGO bit should not be set in the same instruction that turns on the ADC.
Refer to 32.2.7 ADC Conversion Procedure (Basic Mode).
32.2.2 Completion of a Conversion
When any individual conversion is complete, the value already in 32.7.15 ADRES is written into 32.7.16
ADPREV (if ADPSIS = 0) and the new conversion results appear in ADRES. When the conversion
completes, the ADC module will:
Clear the ADGO bit (unless the ADCONT bit is set)
Set the ADIF Interrupt Flag bit
Set the ADMATH bit
Update 32.7.17 ADACC
After every conversion when ADDSEN = 0, or after every other conversion when ADDSEN = 1, the
following events occur:
32.7.19 ADERR is calculated
ADTIF interrupt is set if ADERR calculation meets threshold comparison
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Important:  Filter and threshold computations occur after the conversion itself is complete. As
such, interrupt handlers responding to ADIF should check ADTIF before reading filter and
threshold results.
32.2.3 Terminating a Conversion
If a conversion must be terminated before completion, the ADGO bit can be cleared in software. The
partial conversion results will be discarded and the ADRES registers will retain the value from the
previous conversion.
Important:  A device Reset forces all registers to their Reset state. Thus, the ADC module is
turned off and any pending conversion is terminated.
32.2.4 ADC Operation During Sleep
The ADC module can operate during Sleep. This requires the ADC clock source to be set to the FRC
option. When the FRC oscillator source is selected, the ADC waits one additional instruction before
starting the conversion. This allows the SLEEP instruction to be executed, which can reduce system noise
during the conversion. If the ADC interrupt is enabled, the device will wake-up from Sleep when the
conversion completes. If the ADC interrupt is disabled, the ADC module is turned off after the conversion
completes, although the ADON bit remains set.
32.2.5 External Trigger During Sleep
If the external trigger is received during Sleep while the ADC clock source is set to the FRC, the ADC
module will perform the conversion and set the ADIF bit upon completion.
If an external trigger is received when the ADC clock source is something other than FRC, the trigger will
be recorded, but the conversion will not begin until the device exits Sleep.
32.2.6 Auto-Conversion Trigger
The auto-conversion trigger allows periodic ADC measurements without software intervention. When a
rising edge of the selected source occurs, the ADGO bit is set by hardware.
The auto-conversion trigger source is selected with the ADACT bits.
Using the auto-conversion trigger does not assure proper ADC timing. It is the user’s responsibility to
ensure that the ADC timing requirements are met. See the following table for auto-conversion sources.
Table 32-3.  ADC Auto-Conversion Trigger Sources
ADACT Auto-conversioin Trigger Source
11111 Software write to ADPCH
11110 Reserved, do not use
11101 Software read of ADRESH
11100 Software read of ADERRH
11000 to 11011 Reserved, do not use
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...........continued
ADACT Auto-conversioin Trigger Source
10111 CLC8_out
10110 CLC7_out
10101 CLC6_out
10100 CLC5_out
10011 CLC4_out
10010 CLC3_out
10001 CLC2_out
10000 CLC1_out
01111 Interrupt-on-change Interrupt Flag
01110 C2_out
01101 C1_out
01100 PWM4_out
01011 PWM3_out
01010 CCP2_trigger
01001 CCP1_trigger
01000 TMR6_postscaled
00111 TMR5_overflow
00110 TMR4_postscaled
00101 TMR3_overflow
00100 TMR2_postscaled
00011 TMR1_overflow
00010 TMR0_overflow
00001 Pin selected by ADACTPPS
00000 External Trigger Disabled
32.2.7 ADC Conversion Procedure (Basic Mode)
This is an example procedure for using the ADC to perform an Analog-to-Digital Conversion:
1. Configure Port:
1.1. Disable pin output driver (Refer to the TRISx register)
1.2. Configure pin as analog (Refer to the ANSELx register)
2. Configure the ADC module:
2.1. Select ADC conversion clock
2.2. Configure voltage reference
2.3. Select ADC input channel (precharge+acquisition)
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2.4. Turn on ADC module
3. Configure ADC interrupt (optional):
3.1. Clear ADC interrupt flag
3.2. Enable ADC interrupt
3.3. Enable peripheral interrupt (PEIE bit)
3.4. Enable global interrupt (GIE bit)(1)
4. If ADACQ = 0, software must wait the required acquisition time(2).
5. Start conversion by setting the ADGO bit.
6. Wait for ADC conversion to complete by one of the following:
6.1. Polling the ADGO bit
6.2. Waiting for the ADC interrupt (interrupts enabled)
7. Read ADC Result.
8. Clear the ADC interrupt flag (required if interrupt is enabled).
Important: 
1. With global interrupts disabled, the device will wake from Sleep but will not enter an
Interrupt Service Routine.
2. Refer to 32.3 ADC Acquisition Requirements.
Example 32-1. ADC Conversion (assembly)
; This code block configures the ADC for polling, Vdd and Vss references,
; FRC oscillator, and AN0 input.
; Conversion start & polling for completion are included.
BANKSEL ADCON1
clrf ADCON1 ;
clrf ADCON2 ; Legacy mode, no filtering, ADRES->ADPREV
clrf ADCON3 ; no math functions
clrf ADREF ; Vref = Vdd & Vss
clrf ADPCH ; select RA0/AN0
clrf ADACQ ; software controlled acquisition time
clrf ADCAP ; default S&H capacitance
clrf ADRPT ; no repeat measurements
clrf ADACT ; auto-conversion disabled
movlw B'10010100' ; ADC On, right-justified, FRC clock
movwf ADCON0
BANKSEL TRISA ;
bsf TRISA,0 ; Set RA0 to input
BANKSEL ANSEL ;
bsf ANSEL,0 ; Set RA0 to analog
call SampleTime ; Acquisiton delay
BANKSEL ADCON0
bsf ADCON0,ADGO ; Start conversion
btfsc ADCON0,ADGO ; Is conversion done?
goto $-2 ; No, test again
BANKSEL ADRESH ;
movf ADRESH,W ; Read upper 2 bits
movwf RESULTHI ; store in GPR space
movf ADRESL,W ; Read lower 8 bits
movwf RESULTLO ; Store in GPR space
Example 32-2. ADC Conversion (C)
/*This code block configures the ADC
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for polling, VDD and VSS references, ADCRC
oscillator and AN0 input.
Conversion start & polling for completion
are included.
*/
void main() {
//System Initialize
initializeSystem();
//Setup ADC
ADCON0bits.FM = 1; //right justify
ADCON0bits.CS = 1; //FRC Clock
ADPCH = 0x00; //RA0 is Analog channel
TRISAbits.TRISA0 = 1; //Set RA0 to input
ANSELAbits.ANSELA0 = 1; //Set RA0 to analog
ADCON0bits.ON = 1; //Turn ADC On
while (1) {
ADCON0bits.GO = 1; //Start conversion
while (ADCON0bits.GO); //Wait for conversion done
resultHigh = ADRESH; //Read result
resultLow = ADRESL; //Read result
}
}
32.3 ADC Acquisition Requirements
For the ADC to meet its specified accuracy, the charge holding capacitor (CHOLD) must be allowed to fully
charge to the input channel voltage level. The analog input model is shown in Figure 32-5. The source
impedance (RS) and the internal sampling switch (RSS) impedance directly affect the time required to
charge the capacitor CHOLD. The sampling switch (RSS) impedance varies over the device voltage (VDD),
refer to Figure 32-5. The maximum recommended impedance for analog sources is 10 kΩ. As the source
impedance is decreased, the acquisition time may be decreased. After the analog input channel is
selected (or changed), an ADC acquisition must be completed before the conversion can be started. To
calculate the minimum acquisition time, Figure 32-4 may be used. This equation assumes that 1/2 LSb
error is used (1024 steps for the ADC). The 1/2 LSb error is the maximum error allowed for the ADC to
meet its specified resolution.
Figure 32-4. Acquisition Time Example
Assumptions: Temperature = 50°C; External impedance = 10kΩ; VDD = 5.0V
TACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
 = ++
 = 2 ++ 25°0.05/°
The value for TC can be approximated with the following equations:
 11
2+ 1 1= ; [1] VCHOLD charged to within ½ lsb
 1
 = ; [2] VCHOLD charge response to VAPPLIED
 1
 = 11
2+ 1 1 ; Combining [1] and [2]
Note: Where n = ADC resolution in bits
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Solving for TC:
=   + + 1/2047
=10 1Ω + 7Ω + 10Ω 0.0004885
= 1.37
Therefore:
 = 2 + 892 + 50° 25°0.05/°
 = 4.62 
Note: 
1. The reference voltage (VREF) has no effect on the equation, since it cancels itself out.
2. The charge holding capacitor (CHOLD) is not discharged after each conversion.
3. The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the
pin leakage specification.
Figure 32-5. Analog Input Model
CPIN
VA
Rs
Analog
5 pF
V
DD
VT0.6V
V
T0.6V ILEAKAGE(1)
RIC 1k
Sampling
Switch
SS Rss
C
HOLD = 10 pF
Ref-
6V
Sampling Switch
5V
4V
3V
2V
5 6 7 8 9 10 11
(k)
VDD
Legend:
CPIN
VT
ILEAKAGE
RIC
SS
C
HOLD
= Input Capacitance
= Threshold Voltage
= Leakage current at the pin due to
= Interconnect Resistance
= Sampling Switch
= Sample/Hold Capacitance
various junctions
RSS
SS = Resistance of Sampling Switch
Input
pin
Rev. 30-000114A
5/16/2017
R
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Figure 32-6. ADC Transfer Function
3FFh
3FEh
ADC Output Code
3FDh
3FCh
03h
02h
01h
00h
Full-Scale
3FBh
0.5 LSB
REF- Zero-Scale
Transition REF+
Transition
1.5 LSB
Full-Scale Range
Analog Input Voltage
Rev. 30-000115A
5/16/2017
32.4 Capacitive Voltage Divider (CVD) Features
The ADC module contains several features that allow the user to perform a relative capacitance
measurement on any ADC channel using the internal ADC Sample-and-Hold capacitance as a reference.
This relative capacitance measurement can be used to implement capacitive touch or proximity sensing
applications. The following figure shows the basic block diagram of the CVD portion of the ADC module.
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Figure 32-7. Hardware Capacitive Voltage Divider Block Diagram
Rev. 10-000322B
10/4/2017
ANx
ANx
Multiplexer
Additional
Sample
Capacitors
ADPPOL & Precharge
VDD
ADC
ADCAP
ADPPOL & Precharge
ADPPOL & Precharge
ADPPOL & Precharge
Precharge
VDD
32.4.1 CVD Operation
A CVD operation begins with the ADC’s internal Sample-and-Hold capacitor (CHOLD) being disconnected
from the path which connects it to the external capacitive sensor node. While disconnected, CHOLD is
precharged to VDD or VSS the sensor node is also charged to VSS or VDD, respectively to the level
opposite that of CHOLD. When the precharge phase is complete, the VDD/VSS bias paths for the two nodes
are shut off and the paths between CHOLD and the external sensor node is reconnected, at which time the
acquisition phase of the CVD operation begins. During acquisition, a capacitive voltage divider is formed
between the precharged CHOLD and sensor nodes, which results in a final voltage level setting on CHOLD
which is determined by the capacitances and precharge levels of the two nodes. After acquisition, the
ADC converts the voltage level on CHOLD. This process is then repeated with the selected precharge
levels inverted for both the CHOLD and the sensor nodes. The waveform for two CVD measurements,
which is known as differential CVD measurement, is shown in the following figure.
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Figure 32-8. Differential CVD Measurement Waveform
Rev. 10-000335A
10/2/2017
Precharge Acquire Convert Precharge Acquire Convert
First Sample Second Sample
External Capacitive Sensor
VDD
VSS
Time
Voltage
ADC Sample-and-Hold Capacitor
32.4.2 Precharge Control
The Precharge stage is an optional period of time that brings the external channel and internal Sample-
and-Hold capacitor to known voltage levels. Precharge is enabled by writing a nonzero value to the
ADPRE register. This stage is initiated when an ADC conversion begins, either from setting the ADGO
bit, a Special Event Trigger, or a conversion restart from the computation functionality. If the ADPRE
register is cleared when an ADC conversion begins, this stage is skipped.
During the precharge time, CHOLD is disconnected from the outer portion of the sample path that leads to
the external capacitive sensor and is connected to either VDD or VSS, depending on the value of the
ADPPOL bit. At the same time, the port pin logic of the selected analog channel is overridden to drive a
digital high or low out, in order to precharge the outer portion of the ADC’s sample path, which includes
the external sensor. The output polarity of this override is also determined by the ADPPOL bit such that
the external sensor cap is charged opposite that of the internal CHOLD cap. The amount of time that this
charging needs is controlled by the ADPRE register.
Important:  The external charging overrides the TRIS setting of the respective I/O pin. If there
is a device attached to this pin, precharge should not be used.
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32.4.3 Acquisition Control for CVD (ADPRE > 0)
The Acquisition stage allows time for the voltage on the internal Sample-and-Hold capacitor to charge or
discharge from the selected analog channel. This acquisition time is controlled by the ADACQ register.
When ADPRE = 0, acquisition starts at the beginning of conversion. When ADPRE > 0, the acquisition
stage begins when precharge ends.
At the start of the acquisition stage, the port pin logic of the selected analog channel is overridden to turn
off the digital high/low output drivers so they do not affect the final result of the charge averaging. Also,
the selected ADC channel is connected to CHOLD. This allows charge averaging to proceed between the
precharged channel and the CHOLD capacitor.
Important:  When ADPRE > 0 setting ADACQ to ‘0’ will set a maximum acquisition time (256
ADC clock cycles). When precharge is disabled, setting ADACQ to ‘0’ will disable hardware
acquisition time control.
32.4.4 Guard Ring Outputs
Figure 32-9 shows a typical guard ring circuit. CGUARD represents the capacitance of the guard ring trace
placed on the PCB board. The user selects values for RA and RB that will create a voltage profile on
CGUARD, which will match the selected acquisition channel.
The purpose of the guard ring is to generate a signal in phase with the CVD sensing signal to minimize
the effects of the parasitic capacitance on sensing electrodes. It also can be used as a mutual drive for
mutual capacitive sensing. For more information about active guard and mutual drive, see Application
Note AN1478, “mTouchTM Sensing Solution Acquisition Methods Capacitive Voltage Divider”.
The ADC has two guard ring drive outputs, ADGRDA and ADGRDB. These outputs can be routed
through PPS controls to I/O pins (see “Peripheral Pin Select (PPS) Module” for details). The polarity of
these outputs are controlled by the ADGPOL and ADIPEN bits.
At the start of the first precharge stage, both outputs are set to match the ADGPOL bit. Once the
acquisition stage begins, ADGRDA changes polarity, while ADGRDB remains unchanged. When
performing a double sample conversion, setting the ADIPEN bit causes both guard ring outputs to
transition to the opposite polarity of ADGPOL at the start of the second precharge stage, and ADGRDA
toggles again for the second acquisition. For more information on the timing of the guard ring output, refer
to Figure 32-9 and Figure 32-10.
Figure 32-9. Guard Ring Circuit
CGUARD
RA
RB
ADGRDA
ADGRDB
Rev. 30-000120A
5/16/2017
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Figure 32-10. Differential CVD with Guard Ring Output Waveform
Rev. 10-000336A
10/2/2017
Precharge Acquire Convert Precharge Acquire Convert
First Sample Second Sample
External Capacitive Sensor
VDD
VSS
Time
Voltage
ADGRDA
ADGRDB
Guard Ring Capacitance
Figure 32-11. Hardware CVD Sequence Timing Diagram
T
AD
1T
AD
2T
AD
3 T
AD
4 T
AD
5T
AD
6 T
AD
7T
AD
8 T
AD
11
Set GO/DONE bit
Holding capacitor C
HOLD
is disconnected from analog input (typically 100 ns)
T
AD
9 T
AD
10
T
CY
- T
AD
AADRES0H:AADRES0L is loaded,
ADIF bit is set,
Conversion starts
b0
b9 b6 b5 b4 b3 b2 b1
b8 b7
On the following cycle:
1-255 T
INST
1-255 T
INST
Precharge Acquisition/
Sharing Time
Time Conversion Time
If ADPRE
0
If ADACQ
0
If ADPRE =
0
If ADACQ =
0
GO/DONE bit is cleared
(Traditional Timing of ADC Conversion)
External and Internal
Channels are
charged/discharged
External and Internal
Channels share
charge
(Traditional Operation Start)
(T
PRE
) (T
ACQ
)T
AD
1T
AD
2T
AD
3 T
AD
4 T
AD
5T
AD
6 T
AD
7T
AD
8 T
AD
11
Set GO/DONE bit
Holding capacitor C
HOLD
is disconnected from analog input (typically 100 ns)
T
AD
9 T
AD
10
T
CY
- T
AD
AADRES0H:AADRES0L is loaded,
ADIF bit is set,
Conversion starts
b0
b9 b6 b5 b4 b3 b2 b1
b8 b7
On the following cycle:
1-255 T
INST
1-255 T
INST
Precharge Acquisition/
Sharing Time
Time Conversion Time
If ADPRE
0
If ADACQ
0
If ADPRE =
0
If ADACQ =
0
GO/DONE bit is cleared
(Traditional Timing of ADC Conversion)
External and Internal
Channels are
charged/discharged
External and Internal
Channels share
charge
(Traditional Operation Start)
(T
PRE
) (T
ACQ
)
Rev. 30-000122A
5/16/2017
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32.4.5 Additional Sample-and-Hold Capacitance
Additional capacitance can be added in parallel with the internal Sample-and-Hold capacitor (CHOLD) by
using the ADCAP register. This register selects a digitally programmable capacitance that is added to the
ADC conversion bus, increasing the effective internal capacitance of the Sample-and-Hold capacitor in
the ADC module. This is used to improve the match between internal and external capacitance for a
better sensing performance. The additional capacitance does not affect analog performance of the ADC
because it is not connected during conversion. See Figure 32-12.
32.5 Computation Operation
The ADC module hardware is equipped with post conversion computation features. These features
provide data post-processing functions that can be operated on the ADC conversion result, including
digital filtering/averaging and threshold comparison functions.
Figure 32-12. Computational Features Simplified Block Diagram
Rev. 10-000260B
8/4/2015
ADRES
Average/
Filter 1
0
ADPREV
Error
Calculation
ADSTPT
ADFILT
Threshold
Logic
ADPSIS
ADCALC<2:0>
ADMD<2:0>
ADUTHR ADLTHR
Set
Interrupt
Flag
ADERR
The operation of the ADC computational features is controlled by the ADMD bits.
The module can be operated in one of five modes:
Basic: This is a legacy mode. In this mode, ADC conversion occurs on single (ADDSEN = 0) or
double (ADDSEN = 1) samples. ADIF is set after each conversion is complete.
Accumulate: With each trigger, the ADC conversion result is added to the accumulator and ADCNT
increments. ADIF is set after each conversion. ADTIF is set according to the calculation mode.
Average: With each trigger, the ADC conversion result is added to the accumulator. When the
ADRPT number of samples have been accumulated, a threshold test is performed. Upon the next
trigger, the accumulator is cleared. For the subsequent tests, additional ADRPT samples are required
to be accumulated.
Burst Average: At the trigger, the accumulator is cleared. The ADC conversion results are then
collected repetitively until ADRPT samples are accumulated and finally the threshold is tested.
Low-Pass Filter (LPF): With each trigger, the ADC conversion result is sent through a filter. When
ADRPT samples have occurred, a threshold test is performed. Every trigger after that the ADC
conversion result is sent through the filter and another threshold test is performed.
The five modes are summarized in the following table.
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Table 32-4. Computation Modes
rotatethispage90 Register Clear
Event
Value after Cycle(2)
Completion
Threshold Operations Value at ADTIF Interrupt
Mode ADMD ADACC and
ADCNT
ADACC(1) ADCNT Retrigger Threshold Test Interrupt ADAOV ADFLTR ADCNT
Basic 0 ADACLR = 1Unchanged Unchanged No Every Sample If
threshold=true
N/A N/A count
Accumulate 1 ADACLR = 1S1 + ADACC
or
(S2-S1) +
ADACC
If (ADCNT=FF):
ADCNT,
otherwise:
ADCNT+1
No Every Sample If
threshold=true
ADACC
Overflow
ADACC/
2ADCRS
count
Average 2 ADACLR = 1 or
ADCNT>=ADRPT
at ADGO or
retrigger
S1 + ADACC
or
(S2-S1) +
ADACC
If (ADCNT=FF):
ADCNT,
otherwise:
ADCNT+1
No If
ADCNT>=ADRPT
If
threshold=true
ADACC
Overflow
ADACC/
2ADCRS
count
Burst
Average
3 ADACLR = 1 or
ADGO set or
retrigger
Each
repetition:
same as
Average
End with
sum of all
samples
Each repetition:
same as
Average
End with
ADCNT=ADRPT
Repeat while
ADCNT<ADRPT
If
ADCNT>=ADRPT
If
threshold=true
ADACC
Overflow
ADACC/
2ADCRS
ADRPT
Low-pass
Filter
4 ADACLR = 1S1+ADACC-
ADACC/
2ADCRS
or
(S2-
S1)+ADACC-
ADACC/
2ADCRS
If (ADCNT=FF):
ADCNT,
otherwise:
ADCNT+1
No If
ADCNT>=ADRPT
If
threshold=true
ADACC
Overflow
Filtered
Value
count
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...........continued
rotatethispage90 Register Clear
Event
Value after Cycle(2)
Completion
Threshold Operations Value at ADTIF Interrupt
Mode ADMD ADACC and
ADCNT
ADACC(1) ADCNT Retrigger Threshold Test Interrupt ADAOV ADFLTR ADCNT
Note: 
1. S1 and S2 are abbreviations for Sample 1 and Sample 2, respectively. When ADDSEN = 0, S1 = ADRES; When ADDSEN = 1, S1 =
ADPREV and S2 = ADRES.
2. When ADDSEN = 0 then Cycle means one conversion. When ADDSEN = 1 then Cycle means two conversions.
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32.5.1 Digital Filter/Average
The digital filter/average module consists of an accumulator with data feedback options, and control logic
to determine when threshold tests need to be applied. The accumulator is a 16-bit wide register that can
be accessed through the 32.7.17 ADACC registers.
Upon each trigger event (the ADGO bit set or external event trigger), the ADC conversion result is added
to the accumulator. If the accumulated value exceeds 2(accumulator_width)-1 = 216 = 65535, the ADAOV
overflow bit is set.
The number of samples to be accumulated is determined by the ADRPT (A/D Repeat Setting) register.
Each time a sample is added to the accumulator, the ADCNT register is incremented. Once ADRPT
samples are accumulated (ADCNT = ADRPT), an accumulator clear command can be issued by the
software by setting the ADACLR bit. Setting the ADACLR bit will also clear the ADAOV (Accumulator
overflow) bit, as well as the ADCNT register. The ADACLR bit is cleared by the hardware when
accumulator clearing action is complete.
Important:  When ADC is operating from FRC, five FRC clock cycles are required to execute
the ADACC clearing operation.
The ADCRS bits control the data shift on the accumulator result, which effectively divides the value in
accumulator (32.7.17 ADACC) registers. For the Accumulate mode of the digital filter, the shift provides a
simple scaling operation. For the Average/Burst Average mode, the shift bits are used to determine
number of samples for averaging. For the Low-pass Filter mode, the shift is an integral part of the filter,
and determines the cutoff frequency of the filter. Table 32-5 shows the -3 dB cutoff frequency in ωT
(radians) and the highest signal attenuation obtained by this filter at nyquist frequency (ωT = π).
Table 32-5. Low-pass Filter -3 dB Cutoff Frequency
ADCRS ωT (radians) @ -3 dB Frequency dB @ Fnyquist=1/(2T)
1 0.72 -9.5
2 0.284 -16.9
3 0.134 -23.5
4 0.065 -29.8
5 0.032 -36.0
6 0.016 -42.0
32.5.2 Basic Mode
Basic mode (ADMD = 000) disables all additional computation features. In this mode, no accumulation
occurs but threshold error comparison is performed. Double sampling, Continuous mode, and all CVD
features are still available, but no features involving the digital filter/average features are used.
32.5.3 Accumulate Mode
In Accumulate mode (ADMD = 001), after every conversion, the ADC result is added to the ADACC
register. The ADACC register is right-shifted by the value of the ADCRS bits. This right-shifted value is
copied in to the ADFLT register. The Formatting mode does not affect the right-justification of the ADACC
value. Upon each sample, ADCNT is also incremented, incrementing the number of samples
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accumulated. After each sample and accumulation, the ADACC value has a threshold comparison
performed on it (see 32.5.7 Threshold Comparison) and the ADTIF interrupt may trigger.
32.5.4 Average Mode
In Average Mode (ADMD = 010), the ADACC registers accumulate with each ADC sample, much as in
Accumulate mode, and the ADCNT register increments with each sample. The ADFLT register is also
updated with the right-shifted value of the ADACC register. The value of the ADCRS bits governs the
number of right shifts. However, in Average mode, the threshold comparison is performed upon ADCNT
being greater than or equal to a user-defined ADRPT value. In this mode when ADRPT = 2^ADCNT, then
the final accumulated value will be divided by number of samples, allowing for a threshold comparison
operation on the average of all gathered samples.
32.5.5 Burst Average Mode
The Burst Average mode (ADMD = 011) acts the same as the Average mode in most respects. The one
way it differs is that it continuously retriggers ADC sampling until the ADCNT value is greater than or
equal to ADRPT, even if Continuous Sampling mode (see 32.5.8 Continuous Sampling Mode) is not
enabled. This allows for a threshold comparison on the average of a short burst of ADC samples.
32.5.6 Low-pass Filter Mode
The Low-pass Filter mode (ADMD = 100) acts similarly to the Average mode in how it handles samples
(accumulates samples until ADCNT value greater than or equal to ADRPT, then triggers threshold
comparison), but instead of a simple average, it performs a low-pass filter operation on all of the samples,
reducing the effect of high-frequency noise on the average, then performs a threshold comparison on the
results. (see 32.5 Computation Operation for a more detailed description of the mathematical operation).
In this mode, the ADCRS bits determine the cutoff frequency of the low-pass filter (as demonstrated by
32.5.1 Digital Filter/Average).
32.5.7 Threshold Comparison
At the end of each computation:
The conversion results are latched and held stable at the end-of-conversion.
The error (32.7.19 ADERR) is calculated based on a difference calculation which is selected by the
ADCALC bits. The value can be one of the following calculations (see Table 32-6 for more details):
The first derivative of single measurements
The CVD result when double-sampling is enabled
The current result vs. a setpoint
The current result vs. the filtered/average result
The first derivative of the filtered/average value
Filtered/average value vs. a setpoint
The result of the calculation (ADERR) is compared to the upper and lower thresholds, 32.7.21
ADUTH and 32.7.20 ADLTH registers, to set the ADUTHR and ADLTHR flag bits. The threshold
logic is selected by ADTMD bits. The threshold trigger option can be one of the following:
Never interrupt
Error is less than lower threshold
Error is greater than or equal to lower threshold
Error is between thresholds (inclusive)
Error is outside of thresholds
Error is less than or equal to upper threshold
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Error is greater than upper threshold
Always interrupt regardless of threshold test results
If the threshold condition is met, the threshold interrupt flag ADTIF is set.
Note: 
1. The threshold tests are signed operations.
2. If ADAOV is set, a threshold interrupt is signaled. It is good practice for threshold interrupt handlers
to verify the validity of the threshold by checking ADAOV.
Table 32-6. ADC Error Calculation Mode
ADCALC
ADERR
Application
ADDSEN = 0 Single-
Sample Mode
ADDSEN = 1 CVD
Double-Sample Mode(1)
111 ADFLTR ADFLTR Filtered results above or below the
threshold.
110 ADRES ADRES Measurement above or below the
threshold
101 ADLFTR-ADSTPT ADFLTR-ADSTPT Average/filtered value vs. setpoint
100 ADPREV-ADFLTR ADPREV-ADFLTR First derivative of filtered value(3)
(negative)
011 Reserved Reserved Reserved
010 ADRES-ADFLTR (ADRES-ADPREV)-
ADFLTR
Actual result vs. averaged/filtered
value
001 ADRES-ADSTPT (ADRES-ADPREV)-
ADSTPT
Actual result vs.setpoint
000 ADRES-ADPREV ADRES-ADPREV First derivative of single
measurement(2)
Actual CVD result(1,2)
Note: 
1. When ADDSEN=1, ADERR is computed only after every second sample.
2. When ADPSIS = 0.
3. When ADPSIS = 1.
32.5.8 Continuous Sampling Mode
Setting the ADCONT bit register automatically retriggers a new conversion cycle after updating the
ADACC register. That means the ADGO bit is set to generate automatic retriggering, until the device
Reset occurs or the ADSOI A/D Stop-on-interrupt bit is set (correct logic).
32.5.9 Double Sample Conversion
Double sampling is enabled by setting the ADDSEN bit. When this bit is set, two conversions are required
before the module will calculate threshold error. Each conversion must still be triggered separately when
ADCONT = 0. The first conversion will set the ADMATH bit and update ADACC, but will not calculate
ADERR or trigger ADTIF. When the second conversion completes, the first value is transferred to
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ADPREV (depending on the setting of ADPSIS) and the value of the second conversion is placed into
ADRES. Only upon the completion of the second conversion is ADERR calculated and ADTIF triggered
(depending on the value of ADCALC).
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32.6 Register Summary - ADC Control
Address Name Bit Pos.
0x0F51 ADACT 7:0 ADACT[4:0]
0x0F52 ADCLK 7:0 ADCS[5:0]
0x0F53 ADREF 7:0 ADNREF ADPREF[1:0]
0x0F54 ADCON1 7:0 ADPPOL ADIPEN ADGPOL ADDSEN
0x0F55 ADCON2 7:0 ADPSIS ADCRS[2:0] ADACLR ADMD[2:0]
0x0F56 ADCON3 7:0 ADCALC[2:0] ADSOI ADTMD[2:0]
0x0F57 ADACQ 7:0 ADACQ[7:0]
0x0F58 ADCAP 7:0 ADCAP[4:0]
0x0F59 ADPRE 7:0 ADPRE[7:0]
0x0F5A ADPCH 7:0 ADPCH[5:0]
0x0F5B ADCON0 7:0 ADON ADCONT ADCS ADFM ADGO
0x0F5C ADPREV
7:0 ADPREVL[7:0]
15:8 ADPREVH[7:0]
0x0F5E ADRES
7:0 ADRESL[7:0]
15:8 ADRESH[7:0]
0x0F60 ADSTAT 7:0 ADAOV ADUTHR ADLTHR ADMATH ADSTAT[2:0]
0x0F61 ADRPT 7:0 ADRPT[7:0]
0x0F62 ADCNT 7:0 ADCNT[7:0]
0x0F63 ADSTPT
7:0 ADSTPTL[7:0]
15:8 ADSTPTH[7:0]
0x0F65 ADLTH
7:0 ADLTHL[7:0]
15:8 ADLTHH[7:0]
0x0F67 ADUTH
7:0 ADUTHL[7:0]
15:8 ADUTHH[7:0]
0x0F69 ADERR
7:0 ADERRL[7:0]
15:8 ADERRH[7:0]
0x0F6B ADACC
7:0 ADACCL[7:0]
15:8 ADACCH[7:0]
0x0F6D ADFLTR
7:0 ADFLTRL[7:0]
15:8 ADFLTRH[7:0]
32.7 Register Definitions: ADC Control
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32.7.1 ADCON0
Name:  ADCON0
Address:  0xF5B
ADC Control Register 0
Bit 7 6 5 4 3 2 1 0
ADON ADCONT ADCS ADFM ADGO
Access R/W R/W R/W R/W R/W/HC
Reset 0 0 0 0 0
Bit 7 – ADON ADC Enable bit
Value Description
1ADC is enabled
0ADC is disabled
Bit 6 – ADCONT ADC Continuous Operation Enable bit
Value Description
1ADGO is retriggered upon completion of each conversion trigger until ADTIF is set (if ADSOI
is set) or until ADGO is cleared (regardless of the value of ADSOI)
0ADC is cleared upon completion of each conversion trigger
Bit 4 – ADCS ADC Clock Selection bit
Value Description
1Clock supplied from FRC dedicated oscillator
0Clock supplied by Fosc, divided according to ADCLK register
Bit 2 – ADFM ADC results Format/alignment Selection
Value Description
1ADRES and ADPREV data are right justified
0ADRES and ADPREV data are left justified, zero-filled
Bit 0 – ADGO ADC Conversion Status bit
Value Description
1ADC conversion cycle in progress. Setting this bit starts an ADC conversion cycle. The bit is
cleared by hardware as determined by the ADCONT bit
0ADC conversion completed/not in progress
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32.7.2 ADCON1
Name:  ADCON1
Address:  0xF54
ADC Control Register 1
Bit 7 6 5 4 3 2 1 0
ADPPOL ADIPEN ADGPOL ADDSEN
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bit 7 – ADPPOL Precharge Polarity bit
Action During 1st Precharge Stage
Value Condition Description
xADPRE=0 Bit has no effect
1ADPRE>0 and ADC input is I/O pin Pin shorted to AVDD
0ADPRE>0 and ADC input is I/O pin Pin shorted to VSS
1ADPRE>0 and ADC input is internal CHOLD Shorted to AVDD
0ADPRE>0 and ADC input is internal CHOLD Shorted to VSS
Bit 6 – ADIPEN A/D Inverted Precharge Enable bit
Value Condition Description
xADDSEN = 0 Bit has no effect
1ADDSEN = 1 The precharge and guard signals in the second conversion cycle are the
opposite polarity of the first cycle
0ADDSEN = 1 Both Conversion cycles use the precharge and guards specified by ADPPOL
and ADGPOL
Bit 5 – ADGPOL Guard Ring Polarity Selection bit
Value Description
1ADC guard Ring outputs start as digital high during Precharge stage
0ADC guard Ring outputs start as digital low during Precharge stage
Bit 0 – ADDSEN Double-Sample Enable bit
Value Description
1Two conversions are processed as a pair. The selected computation is performed after every
second conversion.
0Selected computation is performed after every conversion
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32.7.3 ADCON2
Name:  ADCON2
Address:  0xF55
ADC Control Register 2
Bit 7 6 5 4 3 2 1 0
ADPSIS ADCRS[2:0] ADACLR ADMD[2:0]
Access R/W R/W R/W R/W R/W/HC R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 – ADPSIS ADC Previous Sample Input Select bits
Value Description
1ADFLTR is transferred to ADPREV at start-of-conversion
0ADRES is transferred to ADPREV at start-of-conversion
Bits 6:4 – ADCRS[2:0] ADC Accumulated Calculation Right Shift Select bits
Value Condition Description
1 to 6 ADMD = 'b100 Low-pass filter time constant is 2ADCRS, filter gain is 1:1(2)
1 to 6 ADMD =' b011 to 'b001 The accumulated value is right-shifted by ADCRS (divided by
2ADCRS)(1,2)
xADMD ='b000 These bits are ignored
Bit 3 – ADACLR  A/D Accumulator Clear Command bit(3)
Value Description
1ADACC, ADAOV and ADCNT registers are cleared
0Clearing action is complete (or not started)
Bits 2:0 – ADMD[2:0]  ADC Operating Mode Selection bits(4)
Value Description
111-101 Reserved
100 Low-pass Filter mode
011 Burst Average mode
010 Average mode
001 Accumulate mode
000 Basic (Legacy) mode
Note: 
1. To correctly calculate an average, the number of samples (set in ADRPT) must be 2ADCRS.
2. ADCRS = 'b111 and 'b000 are reserved.
3. This bit is cleared by hardware when the accumulator operation is complete; depending on
oscillator selections, the delay may be many instructions.
4. See Table 32-4 for Full mode descriptions.
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32.7.4 ADCON3
Name:  ADCON3
Address:  0xF56
ADC Control Register 3
Bit 7 6 5 4 3 2 1 0
ADCALC[2:0] ADSOI ADTMD[2:0]
Access R/W R/W R/W R/W/HC R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bits 6:4 – ADCALC[2:0] ADC Error Calculation Mode Select bits
See Table 32-6 table for selection details.
Bit 3 – ADSOI ADC Stop-on-Interrupt bit
Value Condition Description
1ADCONT = 1ADGO is cleared when the threshold conditions are met, otherwise the
conversion is retriggered
0ADCONT = 1ADGO is not cleared by hardware, must be cleared by software to stop
retriggers
xADCONT = 0This bit is not used
Bits 2:0 – ADTMD[2:0] Threshold Interrupt Mode Select bits
Value Description
111 Interrupt regardless of threshold test results
110 Interrupt if ADERR>ADUTH
101 Interrupt if ADERR≤ADUTH
100 Interrupt if ADERR<ADLTH or ADERR>ADUTH
011 Interrupt if ADERR>ADLTH and ADERR<ADUTH
010 Interrupt if ADERR≥ADLTH
001 Interrupt if ADERR<ADLTH
000 Never interrupt
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32.7.5 ADSTAT
Name:  ADSTAT
Address:  0xF60
ADC Status Register
Bit 7 6 5 4 3 2 1 0
ADAOV ADUTHR ADLTHR ADMATH ADSTAT[2:0]
Access R/C/HS/HC RO RO R/C/HS/HC RO RO RO
Reset 0 0 0 0 0 0 0
Bit 7 – ADAOV ADC Accumulator Overflow bit
Value Description
1ADC accumulator or ADERR calculation have overflowed
0ADC accumulator and ADERR calculation have not overflowed
Bit 6 – ADUTHR ADC Module Greater-than Upper Threshold Flag bit
Value Description
1ADERR >ADUTH
0ADERR≤ADUTH
Bit 5 – ADLTHR ADC Module Less-than Lower Threshold Flag bit
Value Description
1ADERR<ADLTH
0ADERR≥ADLTH
Bit 4 – ADMATH ADC Module Computation Status bit
Value Description
1Registers ADACC, ADFLTR, ADUTH, ADLTH and the ADAOV bit are updating or have
already updated
0Associated registers/bits have not changed since this bit was last cleared
Bits 2:0 – ADSTAT[2:0]
ADC Module Cycle Multi-Stage Status bits(1)
Value Description
111 ADC module is in 2nd conversion stage
110 ADC module is in 2nd acquisition stage
101 ADC module is in 2nd precharge stage
100 Not used
011 ADC module is in 1st conversion stage
010 ADC module is in 1st acquisition stage
001 ADC module is in 1st precharge stage
000 ADC module is not converting
Note: 
1. If ADCS = 1, and FOSC<FRC, the indicated status may not be valid.
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32.7.6 ADCLK
Name:  ADCLK
Address:  0xF52
ADC Clock Selection Register
Bit 7 6 5 4 3 2 1 0
ADCS[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bits 5:0 – ADCS[5:0] ADC Conversion Clock Select bits
Value Description
nADC Clock frequency = FOSC/(2*(n+1))
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32.7.7 ADREF
Name:  ADREF
Address:  0xF53
ADC Reference Selection Register
Bit 7 6 5 4 3 2 1 0
ADNREF ADPREF[1:0]
Access R/W R/W R/W
Reset 0 0 0
Bit 4 – ADNREF ADC Negative Voltage Reference Selection bit
Value Description
1VREF- is connected to external VREF-
0VREF- is connected to AVSS
Bits 1:0 – ADPREF[1:0] ADC Positive Voltage Reference Selection bits
Value Description
11 VREF+ is connected to internal Fixed Voltage Reference (FVR) module
10 VREF+ is connected to external VREF+
01 Reserved
00 VREF+ is connected to VDD
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32.7.8 ADPCH
Name:  ADPCH
Address:  0xF5A
ADC Positive Channel Selection Register
Bit 7 6 5 4 3 2 1 0
ADPCH[5:0]
Access R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0
Bits 5:0 – ADPCH[5:0] ADC Positive Input Channel Selection bits
See Channel Selection Table for input selection details.
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32.7.9 ADPRE
Name:  ADPRE
Address:  0xF59
ADC Precharge Time Control Register
Bit 7 6 5 4 3 2 1 0
ADPRE[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – ADPRE[7:0] Precharge Time Select bits
Value Description
1 to
255
Number of ADC clocks in the precharge time.
0Precharge time is not included in the data conversion cycle
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32.7.10 ADACQ
Name:  ADACQ
Address:  0xF57
ADC Acquisition Time Control Register
Bit 7 6 5 4 3 2 1 0
ADACQ[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – ADACQ[7:0] Acquisition (charge share time) Select bits
Value Description
0x01 to
0xFF
Number of ADC clock periods in the acquisition time
0x00 Acquisition time is not included in the data conversion cycle
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32.7.11 ADCAP
Name:  ADCAP
Address:  0xF58
ADC Additional Sample Capacitor Selection Register
Bit 7 6 5 4 3 2 1 0
ADCAP[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – ADCAP[4:0] ADC Additional Sample Capacitor Selection bits
Value Description
1 to 31 Number of pF in the additional capacitance
0No additional capacitance
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32.7.12 ADRPT
Name:  ADRPT
Address:  0xF61
ADC Repeat Setting Register
Bit 7 6 5 4 3 2 1 0
ADRPT[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – ADRPT[7:0] ADC Repeat Threshold bits
Determines the number of times that the ADC is triggered for a threshold check. When ADCNT reaches
this value the error threshold is checked. Used when the computation mode is Low-pass Filter, Burst
Average, or Average. See Table 32-4 for more details.
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32.7.13 ADCNT
Name:  ADCNT
Address:  0xF62
ADC Repeat Counter Register
Bit 7 6 5 4 3 2 1 0
ADCNT[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:0 – ADCNT[7:0] ADC Repeat Count bits
Counts the number of times that the ADC is triggered before the threshold is checked. When this value
reaches ADPRT then the threshold is checked. Used when the computation mode is Low-pass Filter,
Burst Average, or Average. See Table 32-4 for more details.
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32.7.14 ADFLTR
Name:  ADFLTR
Address:  0xF6D
ADC Filter Register. In Accumulate, Average, and Burst Average mode, this is equal to ADACC right
shifted by the ADCRS bits of ADCON2. In LPF mode, this is the output of the low-pass filter.
Bit 15 14 13 12 11 10 9 8
ADFLTRH[7:0]
Access RO RO RO RO RO RO RO RO
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
ADFLTRL[7:0]
Access RO RO RO RO RO RO RO RO
Reset x x x x x x x x
Bits 15:8 – ADFLTRH[7:0] ADC Filter Output Most Significant bits
Bits 7:0 – ADFLTRL[7:0] ADC Filter Output Least Significant bits
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32.7.15 ADRES
Name:  ADRES
Address:  0xF5E
ADC Result Register
Bit 15 14 13 12 11 10 9 8
ADRESH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
ADRESL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – ADRESH[7:0] ADC Result Register bits. High bits
Value Condition Description
0x00,0x
01,0x02
,0x03
ADFM=1Upper 2 bits of result
0 to
0xFF
ADFM=0Upper 8 bits of result
Bits 7:0 – ADRESL[7:0] ADC Result Register bits. Lower bits
Value Condition Description
0 to
0xFF
ADFM=1Lower 8 bits of result
0x00,0x
40,0x80
,0xC0
ADFM=0Lower 2 bits of result
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32.7.16 ADPREV
Name:  ADPREV
Address:  0xF5C
ADC Previous Result Register
Bit 15 14 13 12 11 10 9 8
ADPREVH[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
ADPREVL[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – ADPREVH[7:0] Previous ADC Result Most Significant bits
Value Condition Description
0 to
0xFF
ADPSIS=1Upper byte of ADFLTR at the start of current ADC conversion
varies ADPSIS=0Upper bits of ADRES at the start of current ADC conversion(1)
Bits 7:0 – ADPREVL[7:0] Previous ADC Result Least Significant bits
Value Condition Description
0 to
0xFF
ADPSIS=1Lower byte of ADFLTR at the start of current ADC conversion
varies ADPSIS=0Lower bits of ADRES at the start of current ADC conversion(1)
Note:  If ADPSIS = 0, ADPREVH and ADPREVL are formatted the same way as ADRES is, depending
on the ADFM bit.
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32.7.17 ADACC
Name:  ADACC
Address:  0xF6B
ADC Accumulator Register
See Table 32-4 for more details.
Bit 15 14 13 12 11 10 9 8
ADACCH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bit 7 6 5 4 3 2 1 0
ADACCL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset x x x x x x x x
Bits 15:8 – ADACCH[7:0]
ADC Accumulator Most Significant Byte.
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
Bits 7:0 – ADACCL[7:0]
ADC Accumulator Least Significant Byte.
Reset States: POR/BOR = xxxxxxxx
All Other Resets = uuuuuuuu
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32.7.18 ADSTPT
Name:  ADSTPT
Address:  0xF63
ADC Threshold Setpoint Register
Depending on ADCALC, may be used to determine ADERR. See Table 32-6 for more details.
Bit 15 14 13 12 11 10 9 8
ADSTPTH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
ADSTPTL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – ADSTPTH[7:0]
ADC Threshold Setpoint Most Significant Byte.
Bits 7:0 – ADSTPTL[7:0]
ADC Threshold Setpoint Least Significant Byte.
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32.7.19 ADERR
Name:  ADERR
Address:  0xF69
ADC Setpoint Error Register. ADC Setpoint Error calculation is determined by the ADCALC bits.
Bit 15 14 13 12 11 10 9 8
ADERRH[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
ADERRL[7:0]
Access RO RO RO RO RO RO RO RO
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – ADERRH[7:0]
ADC Setpoint Error MSB
Bits 7:0 – ADERRL[7:0]
ADC Setpoint Error LSB
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32.7.20 ADLTH
Name:  ADLTH
Address:  0xF65
ADC Lower Threshold Register
ADLTH and ADUTH are compared with ADERR to set the ADUTHR and ADLTHR bits of ADSTAT.
Depending on the setting of ADTMD, an interrupt may be triggered by the results of this comparison.
Bit 15 14 13 12 11 10 9 8
ADLTHH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
ADLTHL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – ADLTHH[7:0] ADC Lower Threshold MSB
Bits 7:0 – ADLTHL[7:0] ADC Lower Threshold LSB
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 627
32.7.21 ADUTH
Name:  ADUTH
Address:  0xF67
ADC Upper Threshold Register
ADLTH and ADUTH are compared with ADERR to set the ADUTHR and ADLTHR bits of ADSTAT.
Depending on the setting of ADTMD, an interrupt may be triggered by the results of this comparison.
Bit 15 14 13 12 11 10 9 8
ADUTHH[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
ADUTHL[7:0]
Access R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 15:8 – ADUTHH[7:0] ADC Upper Threshold MSB
Bits 7:0 – ADUTHL[7:0] ADC Upper Threshold LSB
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 628
32.7.22 ADACT
Name:  ADACT
Address:  0xF51
ADC AUTO Conversion Trigger Source Selection Register
Bit 7 6 5 4 3 2 1 0
ADACT[4:0]
Access R/W R/W R/W R/W R/W
Reset 0 0 0 0 0
Bits 4:0 – ADACT[4:0] Auto-Conversion Trigger Select Bits
Value Description
00000
to
11111
See Auto-Conversion Trigger Sources table.
PIC18F26/45/46Q10
(ADC2) Analog-to-Digital Converter with Comp...
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 629
33. (CMP) Comparator Module
Comparators are used to interface analog circuits to a digital circuit by comparing two analog voltages
and providing a digital indication of their relative magnitudes. Comparators are very useful mixed-signal
building blocks because they provide analog functionality independent of program execution. The
PIC18F26/45/46Q10 devices have two comparators (C1/C2).
The analog comparator module includes the following features:
Programmable Input Selection
Programmable Output Polarity
Rising/Falling Output Edge Interrupts
Wake-up from Sleep
CWG Auto-shutdown Source
Selectable Voltage Reference
ADC Auto-Trigger
Odd Numbered Timers (Timer1, Timer3, etc.) Gate
Even Numbered Timers (Timer2, Timer4, etc.) Reset
CCP Capture Mode Input
DSM Modulator Source
Input and Window Signal-to-Signal Measurement Timer
33.1 Comparator Overview
A single comparator is shown in Figure 33-1 along with the relationship between the analog input levels
and the digital output. When the analog voltage at VIN+ is less than the analog voltage at VIN-, the output
of the comparator is a digital low level. When the analog voltage at VIN+ is greater than the analog
voltage at VIN-, the output of the comparator is a digital high level.
Figure 33-1. Single Comparator
+
VIN+
VIN- Output
Output
VIN+
VIN-
Rev. 30-000125A
5/17/2017
Note: 
1. The black areas of the output of the comparator represent the uncertainty due to input offsets and
response time.
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 630
Figure 33-2. Comparator Module Simplified Block Diagram
Rev. 10-000027R
7/19/2017
+
PCH
NCH
EN(1)
EN(1)
EN(1)
HYS
Interrupt
Rising
Edge
D Q
Q1
INTP
INTN
Cx_out
CMxCON0.OUT
CMOUT.MCxOUT
D Q
0
1
SYNC
set bit
CxIF
TRIS bit
CxOUT
CxOUT_sync
-
Interrupt
Falling
Edge
POL
Cx
(From Timer1 Module) T1CLK
To Other
Peripherals
Note 1: When EN = 0, all multiplexer inputs are disconnected and the Comparator will produce a ‘0’ at the output.
PPS
RxyPPS
CxVP
CxVN
See CMxNCH
Register
See CMxPCH
Register
Related Links
33.15.3 CMxNCH
33.15.4 CMxPCH
33.2 Comparator Control
Each comparator has two control registers: CMxCON0 and CMxCON1.
The CMxCON0 register contains Control and Status bits for the following:
Enable
Output
Output Polarity
Hysteresis Enable
Timer1 Output Synchronization
The CMxCON1 register contains Control bits for the following:
Interrupt on Positive/Negative Edge Enables
Positive Input Channel Selection
Negative Input Channel Selection
33.2.1 Comparator Enable
Setting the EN bit enables the comparator for operation. Clearing the CxEN bit disables the comparator,
resulting in minimum current consumption.
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 631
33.2.2 Comparator Output
The output of the comparator can be monitored by reading either the CxOUT bit or the MCxOUT bit.
The comparator output can also be routed to an external pin through the RxyPPS register. The
corresponding TRIS bit must be clear to enable the pin as an output.
Note: 
1. The internal output of the comparator is latched with each instruction cycle. Unless otherwise
specified, external outputs are not latched.
Related Links
17.9.2 RxyPPS
33.2.3 Comparator Output Polarity
Inverting the output of the comparator is functionally equivalent to swapping the comparator inputs. The
polarity of the comparator output can be inverted by setting the CxPOL bit. Clearing the CxPOL bit results
in a non-inverted output.
Table 33-1 shows the output state versus input conditions, including polarity control.
Table 33-1. Comparator Output State vs. Input Conditions
Input Condition CxPOL CxOUT
CxVn > CxVp 0 0
CxVn < CxVp 0 1
CxVn > CxVp 1 1
CxVn < CxVp 1 0
33.3 Comparator Hysteresis
A selectable amount of separation voltage can be added to the input pins of each comparator to provide a
hysteresis function to the overall operation. Hysteresis is enabled by setting the CxHYS bit.
See Comparator Specifications for more information.
Related Links
39.4.9 Comparator Specifications
33.4 Operation With Timer1 Gate
The output resulting from a comparator operation can be used as a source for gate control of the odd
numbered timers (Timer1, Timer3, etc.). See the timer gate section for more information. This feature is
useful for timing the duration or interval of an analog event.
It is recommended that the comparator output be synchronized to the timer by setting the SYNC bit. This
ensures that the timer does not increment while a change in the comparator is occurring. However,
synchronization is only possible with the Timer1 clock source. Synchronization with the other odd
numbered timers is only possible when they use the same clock source as Timer1.
Related Links
19.7 Timer1 Gate
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 632
33.4.1 Comparator Output Synchronization
The output from a comparator can be synchronized with Timer1 by setting the SYNC bit.
Once enabled, the comparator output is latched on the falling edge of the Timer1 source clock. If a
prescaler is used with Timer1, the comparator output is latched after the prescaling function. To prevent a
race condition, the comparator output is latched on the falling edge of the Timer1 clock source and
Timer1 increments on the rising edge of its clock source. See the Figure 33-2 Comparator Block Diagram
and the Timer1 Block Diagram for more information.
Related Links
19. Timer1 Module with Gate Control
33.5 Comparator Interrupt
An interrupt can be generated upon a change in the output value of the comparator for each comparator;
a rising edge detector and a falling edge detector are present.
When either edge detector is triggered and its associated enable bit is set (CxINTP and/or CxINTN bits),
the Corresponding Interrupt Flag bit (CxIF bit of the PIR2 register) will be set.
To enable the interrupt, the following bits must be set:
EN and POL bits
CxIE bit of the PIE2 register
INTP bit (for a rising edge detection)
INTN bit (for a falling edge detection)
PEIE and GIE bits of the INTCON register
The associated interrupt flag bit, CxIF bit of the PIR2 register, must be cleared in software. If another
edge is detected while this flag is being cleared, the flag will still be set at the end of the sequence.
Important:  Although a comparator is disabled, an interrupt can be generated by changing the
output polarity with the CxPOL bit, or by switching the comparator on or off with the CxEN bit.
33.6 Comparator Positive Input Selection
Configuring the PCH bits direct an internal voltage reference or an analog pin to the non-inverting input of
the comparator:
PCH Positive Input Source
111 AVSS
110 FVR_Buffer2
101 DAC_Output
100 CxPCH not connected
011 CxPCH not connected
010 CxPCH not connected
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 633
...........continued
PCH Positive Input Source
001 CxIN1+
000 CxIN0+
Important:  To use CxINy+ pins as analog input, the appropriate bits must be set in the ANSEL
register and the corresponding TRIS bits must also be set to disable the output drivers.
See Fixed Voltage Reference (FVR) for more information on the Fixed Voltage Reference module.
See 5-Bit Digital-to-Analog Converter (DAC) module for more information on the DAC input signal.
Any time the comparator is disabled (CxEN = 0), all comparator inputs are disabled.
Related Links
29. (FVR) Fixed Voltage Reference
31. (DAC) 5-Bit Digital-to-Analog Converter Module
33.7 Comparator Negative Input Selection
The NCH bits direct an analog input pin and internal reference voltage or analog ground to the inverting
input of the comparator:
NCH Negative Input Sources
111 AVSS
110 FVR_Buffer2
101 CxNCH not connected
100 CxNCH not connected
011 CxIN3-
010 CxIN2-
001 CxIN1-
000 CxIN0-
Important:  To use CxINy- pins as analog input, the appropriate bits must be set in the ANSEL
register and the corresponding TRIS bits must also be set to disable the output drivers.
33.8 Comparator Response Time
The comparator output is indeterminate for a period of time after the change of an input source or the
selection of a new reference voltage. This period is referred to as the response time. The response time
of the comparator differs from the settling time of the voltage reference. Therefore, both of these times
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 634
must be considered when determining the total response time to a comparator input change. See the
Comparator and Voltage Reference Specifications in Comparator Specifications and Fixed Voltage
Reference (FVR) Specifications for more details.
Related Links
39.4.9 Comparator Specifications
39.4.11 Fixed Voltage Reference (FVR) Specifications
33.9 Analog Input Connection Considerations
A simplified circuit for an analog input is shown in Figure 33-3. Since the analog input pins share their
connection with a digital input, they have reverse biased ESD protection diodes to VDD and VSS. The
analog input, therefore, must be between VSS and VDD. If the input voltage deviates from this range by
more than 0.6V in either direction, one of the diodes is forward biased and a latch-up may occur.
A maximum source impedance of 10 kΩ is recommended for the analog sources. Also, any external
component connected to an analog input pin, such as a capacitor or a Zener diode, should have very little
leakage current to minimize inaccuracies introduced.
Note: 
1. When reading a PORT register, all pins configured as analog inputs will read as a ‘0’. Pins
configured as digital inputs will convert as an analog input, according to the input specification.
2. Analog levels on any pin defined as a digital input, may cause the input buffer to consume more
current than is specified.
Figure 33-3. Analog Input Model
VA
RS< 10K
VDD
Analog
Input pin
CPIN
5pF VT0.6V
VT0.6V
ILEAKAGE(1)
VSS
RIC
To Comparator
Legend: CPIN = Input Capacitance
ILEAKAGE = Leakage Current at the pin due to various junctions
RIC = Interconnect Resistance
RS= Source Impedance
VA= Analog Voltage
VT= Threshold Voltage
Rev. 10-000071A
8/2/2013
Note:  See Electrical Specifications chapter.
Related Links
39. Electrical Specifications
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 635
33.10 CWG1 Auto-Shutdown Source
The output of the comparator module can be used as an auto-shutdown source for the CWG1 module.
When the output of the comparator is active and the corresponding WGASxE is enabled, the CWG
operation will be suspended immediately.
Related Links
24.11.1.2 External Input Source
33.11 ADC Auto-Trigger Source
The output of the comparator module can be used to trigger an ADC conversion. When the ADACT
register is set to trigger on a comparator output, an ADC conversion will trigger when the comparator
output goes high.
33.12 Even Numbered Timers Reset
The output of the comparator module can be used to reset the even numbered timers (Timer2, Timer4,
etc.). When the TxERS register is appropriately set, the timer will reset when the comparator output goes
high.
33.13 Operation in Sleep Mode
The comparator module can operate during Sleep. The comparator clock source is based on the Timer1
clock source. If the Timer1 clock source is either the system clock (FOSC) or the instruction clock (FOSC/4),
Timer1 will not operate during Sleep, and synchronized comparator outputs will not operate.
A comparator interrupt will wake the device from Sleep. The CxIE bits of the PIEx register must be set to
enable comparator interrupts.
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 636
33.14 Register Summary - Comparator
Address Name Bit Pos.
0x0F30 CM2CON0 7:0 EN OUT POL HYS SYNC
0x0F31 CM2CON1 7:0 INTP INTN
0x0F32 CM2NCH 7:0 NCH[2:0]
0x0F33 CM2PCH 7:0 PCH[2:0]
0x0F34 CM1CON0 7:0 EN OUT POL HYS SYNC
0x0F35 CM1CON1 7:0 INTP INTN
0x0F36 CM1NCH 7:0 NCH[2:0]
0x0F37 CM1PCH 7:0 PCH[2:0]
0x0F38 CMOUT 7:0 MC2OUT MC1OUT
33.15 Register Definitions: Comparator Control
Long bit name prefixes for the comparator peripherals are shown in the table below. Refer to the "Long
Bit Names Section" for more information.
Table 33-2. Comparator Bit Name Prefixes
Peripheral Bit Name Prefix
C1 C1
C2 C2
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 637
33.15.1 CMxCON0
Name:  CMxCON0
Address:  0xF34,0xF30
Comparator x Control Register 0
Bit 7 6 5 4 3 2 1 0
EN OUT POL HYS SYNC
Access R/W RO R/W R/W R/W
Reset 0 0 0 0 0
Bit 7 – EN Comparator Enable bit
Value Description
1Comparator is enabled
0Comparator is disabled and consumes no active power
Bit 6 – OUT Comparator Output bit
Value Condition Description
1If POL = 0 (non-inverted polarity): CxVP > CxVN
0If POL = 0 (non-inverted polarity): CxVP < CxVN
1If POL = 1 (inverted polarity): CxVP < CxVN
0If POL = 1 (inverted polarity): CxVP > CxVN
Bit 4 – POL Comparator Output Polarity Select bit
Value Description
1Comparator output is inverted
0Comparator output is not inverted
Bit 1 – HYS Comparator Hysteresis Enable bit
Value Description
1Comparator hysteresis enabled
0Comparator hysteresis disabled
Bit 0 – SYNC Comparator Output Synchronous Mode bit
Output updated on the falling edge of prescaled Timer1 clock.
Value Description
1Comparator output to Timer1 and I/O pin is synchronous to changes on the prescaled
Timer1 clock.
0Comparator output to Timer1 and I/O pin is asynchronous
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 638
33.15.2 CMxCON1
Name:  CMxCON1
Address:  0xF35,0xF31
Comparator x Control Register 1
Bit 7 6 5 4 3 2 1 0
INTP INTN
Access R/W R/W
Reset 0 0
Bit 1 – INTP Comparator Interrupt on Positive-Going Edge Enable bit
Value Description
1The CxIF interrupt flag will be set upon a positive-going edge of the CxOUT bit
0No interrupt flag will be set on a positive-going edge of the CxOUT bit
Bit 0 – INTN Comparator Interrupt on Negative-Going Edge Enable bit
Value Description
1The CxIF interrupt flag will be set upon a negative-going edge of the CxOUT bit
0No interrupt flag will be set on a negative-going edge of the CxOUT bit
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 639
33.15.3 CMxNCH
Name:  CMxNCH
Address:  0xF36,0xF32
Comparator x Inverting Channel Select Register
Bit 7 6 5 4 3 2 1 0
NCH[2:0]
Access R/W R/W R/W
Reset 0 0 0
Bits 2:0 – NCH[2:0] Comparator Inverting Input Channel Select bits
NCH Negative Input Sources
111 AVSS
110 FVR_Buffer2
101 CxNCH not connected
100 CxNCH not connected
011 CxIN3-
010 CxIN2-
001 CxIN1-
000 CxIN0-
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 640
33.15.4 CMxPCH
Name:  CMxPCH
Address:  0xF37,0xF33
Comparator x Non-Inverting Channel Select Register
PCH Positive Input Source
111 AVSS
110 FVR_Buffer2
101 DAC_Output
100 CxPCH not connected
011 CxPCH not connected
010 CxPCH not connected
001 CxIN1+
000 CxIN0+
Bit 7 6 5 4 3 2 1 0
PCH[2:0]
Access R/W R/W R/W
Reset 0 0 0
Bits 2:0 – PCH[2:0] Comparator Non-Inverting Input Channel Select bits
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 641
33.15.5 CMOUT
Name:  CMOUT
Address:  0xF38
Comparator Output Register
Bit 7 6 5 4 3 2 1 0
MC2OUT MC1OUT
Access RO RO
Reset 0 0
Bits 0, 1 – MCxOUT Mirror copy of CxOUT bit
PIC18F26/45/46Q10
(CMP) Comparator Module
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 642
34. (HLVD) High/Low-Voltage Detect
The HLVD module can be configured to monitor the device voltage. This is useful in battery monitoring
applications.
Complete control of the HLVD module is provided through the HLVDCON0 and HLVDCON1 registers.
The module’s block diagram is shown in the figure below.
Figure 34-1. HLVD Module Block Diagram
Filename: 10-000256A.vsd
Title: HLVD MODULE BLOCK DIAGRAM (WITHOUT EXTERNAL INPUT)
Last Edit: 8/8/2018
First Used: 18(L)F2x/4xK40 (MFAE)
Notes:
Rev. 10-000256A
8/8/2018
HLVDSEL<3:0>
4
+
-
16-to-1 MUX
VDD
HLVDEN
HLVDEN
Band gap
Reference
Volatge
Trigger/
Interrupt
Generation
HLVDINTH HLVDINTL
HLVDIF
HLVDRDY
HLVDOUT
Since the HLVD can be software enabled through the HLVDEN bit, setting and clearing the enable bit
does not produce a false HLVD event glitch. Each time the HLVD module is enabled, the RDY bit can be
used to detect when the module is stable and ready to use.
The INTH and INTL bits determine the overall operation of the module. When INTH is set, the module
monitors for rises in VDD above the trip point set by the bits. When INTL is set, the module monitors for
drops in VDD below the trip point set by the SEL bits. When both the INTH and INTL bits are set, any
changes above or below the trip point set by the SEL bits can be monitored.
The OUT bit can be read to determine if the voltage is greater than or less than the selected trip point.
34.1 Operation
When the HLVD module is enabled, a comparator uses an internally generated voltage reference as the
set point. The set point is compared with the trip point, where each node in the resistor divider represents
a trip point voltage. The “trip point” voltage is the voltage level at which the device detects a high or low-
voltage event, depending on the configuration of the module.
When the supply voltage is equal to the trip point, the voltage tapped off of the resistor array is equal to
the internal reference voltage generated by the voltage reference module. The comparator then
generates an interrupt signal by setting the HLVDIF bit.
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 643
The trip point voltage is software programmable to any of 16 values. The trip point is selected by
programming the SEL bits.
34.2 Setup
To set up the HLVD module:
1. Select the desired HLVD trip point by writing the value to the SEL bits of the HLVDCON1 register.
2. Depending on the application to detect high-voltage peaks or low-voltage drops or both, set the
INTH or INTL bit appropriately.
3. Enable the HLVD module by setting the EN bit.
4. Clear the HLVD interrupt flag (HLVDIF), which may have been set from a previous interrupt.
5. If interrupts are desired, enable the HLVD interrupt by setting the HLVDIE and GIE bits.
An interrupt will not be generated until the RDY bit is set.
Important:  Before changing any module settings (interrupts and tripping point), first
disable the module (EN = 0), make the changes and re-enable the module. This prevents
the generation of false HLVD events.
Related Links
14.13.4 PIR2
14.13.13 PIE3
34.3 Current Consumption
When the module is enabled, the HLVD comparator and voltage divider are enabled and consume static
current. The total current consumption, when enabled, is specified in electrical specification Parameter
D206.
Depending on the application, the HLVD module does not need to operate constantly. To reduce current
consumption, the module can be enabled for short periods where the voltage is checked. After such a
check, the module could be disabled.
Related Links
39.3.3 Power-Down Current (IPD)(1,2)
34.4 HLVD Start-up Time
If the HLVD or other circuits using the internal voltage reference are disabled to lower the device’s current
consumption, the reference voltage circuit will require time to become stable before a low or high-voltage
condition can be reliably detected. This start-up time, TFVRST, is an interval that is independent of device
clock speed. It is specified in electrical specification.
The HLVD interrupt flag is not enabled until TFVRST has expired and a stable reference voltage is reached.
For this reason, brief excursions beyond the set point may not be detected during this interval (see the
figures below).
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 644
Figure 34-2. Low-Voltage Detect Operation (INTL = 1)
VHLVD
VDD
HLVDIF
VHLVD
VDD
Enable HLVD
TFVRST
HLVDIF may not be Set
Enable HLVD
HLVDIF
HLVDIF Cleared in Software
HLVDIF Cleared in Software
HLVDIF Cleared in Software,
CASE 1:
CASE 2:
HLVDIF Remains Set since HLVD Condition still Exists
TFVRST
Band Gap Reference Voltage is Stable
Band Gap Reference Voltage is Stable
HLVDRDY
HLVDRDY
Rev. 30-000141A
5/26/2017
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 645
Figure 34-3. High-Voltage Detect Operation (INTH = 1)
VHLVD
VDD
HLVDIF
VHLVD
VDD
Enable HLVD
TIRVST
HLVDIF may not be Set
Enable HLVD
HLVDIF
HLVDIF Cleared in Software
HLVDIF Cleared in Software
HLVDIF Cleared in Software,
CASE 1:
CASE 2:
HLVDIF Remains Set since HLVD Condition still Exists
TIRVST
HLVDRDY
Band Gap Reference Voltage is Stable
Band Gap Reference Voltage is Stable
HLVDRDY
Rev. 30-000142A
5/26/2017
34.5 Applications
In many applications, it is desirable to detect a drop below, or rise above, a particular voltage threshold.
For example, the HLVD module could be periodically enabled to detect Universal Serial Bus (USB) attach
or detach. This assumes the device is powered by a lower voltage source than the USB when detached.
An attach would indicate a High-Voltage Detect from, for example, 3.3V to 5V (the voltage on USB) and
vice versa for a detach. This feature could save a design a few extra components and an attach signal
(input pin).
For general battery applications, the figure below shows a possible voltage curve. Over time, the device
voltage decreases. When the device voltage reaches voltage, Va, the HLVD logic generates an interrupt
at time, Ta. The interrupt could cause the execution of an Interrupt Service Routine (ISR), which would
allow the application to perform “housekeeping tasks” and a controlled shutdown before the device
voltage exits the valid operating range at TB. This would give the application a time window, represented
by the difference between TA and TB, to safely exit.
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 646
Figure 34-4. Typical Low-Voltage Detect Application
Time
Voltage
VA
VB
TATB
VA= HLVD trip point
VB= Minimum valid device
o per at ing vol tage
Legend:
Rev. 30-000143A
5/26/2017
34.6 Operation During Sleep
When enabled, the HLVD circuitry continues to operate during Sleep. If the device voltage crosses the trip
point, the HLVDIF bit will be set and the device will wake-up from Sleep. Device execution will continue
from the interrupt vector address if interrupts have been globally enabled.
34.7 Operation During Idle and Doze Modes
In both Idle and Doze modes, the module is active and events are generated if peripheral is enabled.
34.8 Effects of a Reset
A device Reset forces all registers to their Reset state. This forces the HLVD module to be turned off.
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 647
34.9 Register Summary - HLVD
Address Name Bit Pos.
0x0F2A HLVDCON0 7:0 EN OUT RDY INTH INTL
0x0F2B HLVDCON1 7:0 SEL[3:0]
34.10 Register Definitions: HLVD Control
Long bit name prefixes for the HLVD peripheral is shown in the following table. Refer to the "Long Bit
Names" section for more information.
Table 34-1. HLVD Long Bit Name Prefixes
Peripheral Bit Name Prefix
HLVD HLVD
Related Links
1.4.2.2 Long Bit Names
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 648
34.10.1 HLVDCON0
Name:  HLVDCON0
Address:  0xF2A
High/Low-Voltage Detect Control Register 0
Bit 7 6 5 4 3 2 1 0
EN OUT RDY INTH INTL
Access R/W RO RO R/W R/W
Reset 0 x x 0 0
Bit 7 – EN High/Low-voltage Detect Power Enable bit
Value Description
1Enables the HLVD module
0Disables the HLVD module
Bit 5 – OUT HLVD Comparator Output bit
Value Description
1Voltage ≤ selected detection limit (SEL)
0Voltage ≥ selected detection limit (SEL)
Bit 4 – RDY Band Gap Reference Voltages Stable Status Flag bit
Value Description
1Indicates HLVD Module is ready and output is stable
0Indicates HLVD Module is not ready
Bit 1 – INTH HLVD Positive going (High Voltage) Interrupt Enable
Value Description
1HLVDIF will be set when voltage ≥ selected detection limit (SEL)
0HLVDIF will not be set
Bit 0 – INTL HLVD Negative going (Low Voltage) Interrupt Enable
Value Description
1HLVDIF will be set when voltage ≤ selected detection limit (SEL)
0HLVDIF will not be set
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 649
34.10.2 HLVDCON1
Name:  HLVDCON1
Address:  0xF2B
Low-Voltage Detect Control Register 1
Bit 7 6 5 4 3 2 1 0
SEL[3:0]
Access R/W R/W R/W R/W
Reset 0 0 0 0
Bits 3:0 – SEL[3:0] High/Low-Voltage Detection Limit Selection bits
Table 34-2. HLVD Detection Limits
SEL Detection Limit
1111 Reserved
1110 to 0000 See High/Low-voltage detect characteristics
Reset States: POR/BOR = 0000
All other resets = uuuu
Related Links
39.4.6 High/Low-Voltage Detect Characteristics
PIC18F26/45/46Q10
(HLVD) High/Low-Voltage Detect
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 650
35. Register Summary
Address Name Bit Pos.
0x0E1F CLCIN0PPS 7:0 PORT[1:0] PIN[2:0]
0x0E20 CLCIN1PPS 7:0 PORT[1:0] PIN[2:0]
0x0E21 CLCIN2PPS 7:0 PORT[1:0] PIN[2:0]
0x0E22 CLCIN3PPS 7:0 PORT[1:0] PIN[2:0]
0x0E23 CLCIN4PPS 7:0 PORT[1:0] PIN[2:0]
0x0E24 CLCIN5PPS 7:0 PORT[1:0] PIN[2:0]
0x0E25 CLCIN6PPS 7:0 PORT[1:0] PIN[2:0]
0x0E26 CLCIN7PPS 7:0 PORT[1:0] PIN[2:0]
0x0E27 CLC1CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E28 CLC1POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E29 CLC1SEL0 7:0 D1S[5:0]
0x0E2A CLC1SEL1 7:0 D2S[5:0]
0x0E2B CLC1SEL2 7:0 D3S[5:0]
0x0E2C CLC1SEL3 7:0 D4S[5:0]
0x0E2D CLC1GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E2E CLC1GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E2F CLC1GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E30 CLC1GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E31 CLC2CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E32 CLC2POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E33 CLC2SEL0 7:0 D1S[5:0]
0x0E34 CLC2SEL1 7:0 D2S[5:0]
0x0E35 CLC2SEL2 7:0 D3S[5:0]
0x0E36 CLC2SEL3 7:0 D4S[5:0]
0x0E37 CLC2GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E38 CLC2GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E39 CLC2GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E3A CLC2GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E3B CLC3CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E3C CLC3POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E3D CLC3SEL0 7:0 D1S[5:0]
0x0E3E CLC3SEL1 7:0 D2S[5:0]
0x0E3F CLC3SEL2 7:0 D3S[5:0]
0x0E40 CLC3SEL3 7:0 D4S[5:0]
0x0E41 CLC3GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E42 CLC3GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E43 CLC3GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E44 CLC3GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E45 CLC4CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E46 CLC4POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E47 CLC4SEL0 7:0 D1S[5:0]
0x0E48 CLC4SEL1 7:0 D2S[5:0]
0x0E49 CLC4SEL2 7:0 D3S[5:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 651
...........continued
Address Name Bit Pos.
0x0E4A CLC4SEL3 7:0 D4S[5:0]
0x0E4B CLC4GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E4C CLC4GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E4D CLC4GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E4E CLC4GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E4F CLC5CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E50 CLC5POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E51 CLC5SEL0 7:0 D1S[5:0]
0x0E52 CLC5SEL1 7:0 D2S[5:0]
0x0E53 CLC5SEL2 7:0 D3S[5:0]
0x0E54 CLC5SEL3 7:0 D4S[5:0]
0x0E55 CLC5GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E56 CLC5GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E57 CLC5GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E58 CLC5GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E59 CLC6CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E5A CLC6POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E5B CLC6SEL0 7:0 D1S[5:0]
0x0E5C CLC6SEL1 7:0 D2S[5:0]
0x0E5D CLC6SEL2 7:0 D3S[5:0]
0x0E5E CLC6SEL3 7:0 D4S[5:0]
0x0E5F CLC6GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E60 CLC6GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E61 CLC6GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E62 CLC6GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E63 CLC7CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E64 CLC7POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E65 CLC7SEL0 7:0 D1S[5:0]
0x0E66 CLC7SEL1 7:0 D2S[5:0]
0x0E67 CLC7SEL2 7:0 D3S[5:0]
0x0E68 CLC7SEL3 7:0 D4S[5:0]
0x0E69 CLC7GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E6A CLC7GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E6B CLC7GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E6C CLC7GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
0x0E6D CLC8CON 7:0 EN OUT INTP INTN MODE[2:0]
0x0E6E CLC8POL 7:0 POL G4POL G3POL G2POL G1POL
0x0E6F CLC8SEL0 7:0 D1S[5:0]
0x0E70 CLC8SEL1 7:0 D2S[5:0]
0x0E71 CLC8SEL2 7:0 D3S[5:0]
0x0E72 CLC8SEL3 7:0 D4S[5:0]
0x0E73 CLC8GLS0 7:0 G1D4T G1D4N G1D3T G1D3N G1D2T G1D2N G1D1T G1D1N
0x0E74 CLC8GLS1 7:0 G2D4T G2D4N G2D3T G2D3N G2D2T G2D2N G2D1T G2D1N
0x0E75 CLC8GLS2 7:0 G3D4T G3D4N G3D3T G3D3N G3D2T G3D2N G3D1T G3D1N
0x0E76 CLC8GLS3 7:0 G4D4T G4D4N G4D3T G4D3N G4D2T G4D2N G4D1T G4D1N
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 652
...........continued
Address Name Bit Pos.
0x0E77 CLCDATA 7:0 MLC8OUT MLC7OUT MLC6OUT MLC5OUT MLC4OUT MLC3OUT MLC2OUT MLC1OUT
0x0E78
...
0x0E87
Reserved
0x0E88 RX2PPS 7:0 PORT[1:0] PIN[2:0]
0x0E89 CK2PPS 7:0 PORT[1:0] PIN[2:0]
0x0E8A SSP2CLKPPS 7:0 PORT[1:0] PIN[2:0]
0x0E8B SSP2DATPPS 7:0 PORT[1:0] PIN[2:0]
0x0E8C SSP2SSPPS 7:0 PORT[1:0] PIN[2:0]
0x0E8D SSP2BUF 7:0 BUF[7:0]
0x0E8E SSP2ADD 7:0 ADD[7:0]
0x0E8F SSP2MSK 7:0 MSK[6:0] MSK0
0x0E90 SSP2STAT 7:0 SMP CKE D/A P S R/W UA BF
0x0E91 SSP2CON1 7:0 WCOL SSPOV SSPEN CKP SSPM[3:0]
0x0E92 SSP2CON2 7:0 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
0x0E93 SSP2CON3 7:0 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
0x0E94 RC2REG 7:0 RCREG[7:0]
0x0E95 TX2REG 7:0 TXREG[7:0]
0x0E96 SP2BRG
7:0 SPBRGL[7:0]
15:8 SPBRGH[7:0]
0x0E98 RC2STA 7:0 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
0x0E99 TX2STA 7:0 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
0x0E9A BAUD2CON 7:0 ABDOVF RCIDL SCKP BRG16 WUE ABDEN
0x0E9B PPSLOCK 7:0 PPSLOCKED
0x0E9C INT0PPS 7:0 PORT PIN[2:0]
0x0E9D INT1PPS 7:0 PORT PIN[2:0]
0x0E9E INT2PPS 7:0 PORT PIN[2:0]
0x0E9F T0CKIPPS 7:0 PORT PIN[2:0]
0x0EA0 T1CKIPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA1 T1GPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA2 T3CKIPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA3 T3GPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA4 T5CKIPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA5 T5GPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA6 T2INPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA7 T4INPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA8 T6INPPS 7:0 PORT[1:0] PIN[2:0]
0x0EA9 ADACTPPS 7:0 PORT[1:0] PIN[2:0]
0x0EAA CCP1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EAB CCP2PPS 7:0 PORT[1:0] PIN[2:0]
0x0EAC CWG1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EAD MDCARLPPS 7:0 PORT[1:0] PIN[2:0]
0x0EAE MDCARHPPS 7:0 PORT[1:0] PIN[2:0]
0x0EAF MDSRCPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB0 RX1PPS 7:0 PORT[1:0] PIN[2:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 653
...........continued
Address Name Bit Pos.
0x0EB1 CK1PPS 7:0 PORT[1:0] PIN[2:0]
0x0EB2 SSP1CLKPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB3 SSP1DATPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB4 SSP1SSPPS 7:0 PORT[1:0] PIN[2:0]
0x0EB5 IPR0 7:0 TMR0IP IOCIP INT2IP INT1IP INT0IP
0x0EB6 IPR1 7:0 OSCFIP CSWIP ADTIP ADIP
0x0EB7 IPR2 7:0 HLVDIP ZCDIP C2IP C1IP
0x0EB8 IPR3 7:0 RC2IP TX2IP RC1IP TX1IP BCL2IP SSP2IP BCL1IP SSP1IP
0x0EB9 IPR4 7:0 TMR6IP TMR5IP TMR4IP TMR3IP TMR2IP TMR1IP
0x0EBA IPR5 7:0 CLC4IP CLC3IP CLC2IP CLC1IP TMR5GIP TMR3GIP TMR1GIP
0x0EBB IPR6 7:0 CLC8IP CLC7IP CLC6IP CLC5IP CCP2IP CCP1IP
0x0EBC IPR7 7:0 SCANIP CRCIP NVMIP CWG1IP
0x0EBD PIE0 7:0 TMR0IE IOCIE INT2IE INT1IE INT0IE
0x0EBE PIE1 7:0 OSCFIE CSWIE ADTIE ADIE
0x0EBF PIE2 7:0 HLVDIE ZCDIE C2IE C1IE
0x0EC0 PIE3 7:0 RC2IE TX2IE RC1IE TX1IE BCL2IE SSP2IE BCL1IE SSP1IE
0x0EC1 PIE4 7:0 TMR6IE TMR5IE TMR4IE TMR3IE TMR2IE TMR1IE
0x0EC2 PIE5 7:0 CLC4IE CLC3IE CLC2IE CLC1IE TMR5GIE TMR3GIE TMR1GIE
0x0EC3 PIE6 7:0 CLC8IE CLC7IE CLC6IE CLC5IE CCP2IE CCP1IE
0x0EC4 PIE7 7:0 SCANIE CRCIE NVMIE CWG1IE
0x0EC5 PIR0 7:0 TMR0IF IOCIF INT2IF INT1IF INT0IF
0x0EC6 PIR1 7:0 OSCFIF CSWIF ADTIF ADIF
0x0EC7 PIR2 7:0 HLVDIF ZCDIF C2IF C1IF
0x0EC8 PIR3 7:0 RC2IF TX2IF RC1IF TX1IF BCL2IF SSP2IF BCL1IF SSP1IF
0x0EC9 PIR4 7:0 TMR6IF TMR5IF TMR4IF TMR3IF TMR2IF TMR1IF
0x0ECA PIR5 7:0 CLC4IF CLC3IF CLC2IF CLC1IF TMR5GIF TMR3GIF TMR1GIF
0x0ECB PIR6 7:0 CLC8IF CLC7IF CLC6IF CLC5IF CCP2IF CCP1IF
0x0ECC PIR7 7:0 SCANIF CRCIF NVMIF CWG1IF
0x0ECD WDTCON0 7:0 WDTPS[4:0] SEN
0x0ECE WDTCON1 7:0 WDTCS[2:0] WINDOW[2:0]
0x0ECF WDTPSL 7:0 PSCNTL[7:0]
0x0ED0 WDTPSH 7:0 PSCNTH[7:0]
0x0ED1 WDTTMR 7:0 WDTTMR[4:0] STATE PSCNT[1:0]
0x0ED2 CPUDOZE 7:0 IDLEN DOZEN ROI DOE DOZE[2:0]
0x0ED3 OSCCON1 7:0 NOSC[2:0] NDIV[3:0]
0x0ED4 OSCCON2 7:0 COSC[2:0] CDIV[3:0]
0x0ED5 OSCCON3 7:0 CSWHOLD SOSCPWR ORDY NOSCR
0x0ED6 OSCSTAT 7:0 EXTOR HFOR MFOR LFOR SOR ADOR PLLR
0x0ED7 OSCEN 7:0 EXTOEN HFOEN MFOEN LFOEN SOSCEN ADOEN
0x0ED8 OSCTUNE 7:0 HFTUN[5:0]
0x0ED9 OSCFRQ 7:0 HFFRQ[3:0]
0x0EDA VREGCON 7:0 PMSYS[1:0] VREGPM[1:0]
0x0EDB BORCON 7:0 SBOREN BORRDY
0x0EDC PMD0 7:0 SYSCMD FVRMD HLVDMD CRCMD SCANMD NVMMD CLKRMD IOCMD
0x0EDD PMD1 7:0 TMR6MD TMR5MD TMR4MD TMR3MD TMR2MD TMR1MD TMR0MD
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 654
...........continued
Address Name Bit Pos.
0x0EDE PMD2 7:0 DACMD ADCMD CMP2MD CMP1MD ZCDMD
0x0EDF PMD3 7:0 CLC8MD CLC7MD CLC6MD CLC5MD PWM4MD PWM3MD CCP2MD CCP1MD
0x0EE0 PMD4 7:0 UART2MD UART1MD MSSP2MD MSSP1MD CWG1MD
0x0EE1 PMD5 7:0 CLC4MD CLC3MD CLC2MD CLC1MD DSMMD
0x0EE2 RA0PPS 7:0 PPS[4:0]
0x0EE3 RA1PPS 7:0 PPS[4:0]
0x0EE4 RA2PPS 7:0 PPS[4:0]
0x0EE5 RA3PPS 7:0 PPS[4:0]
0x0EE6 RA4PPS 7:0 PPS[4:0]
0x0EE7 RA5PPS 7:0 PPS[4:0]
0x0EE8 RA6PPS 7:0 PPS[4:0]
0x0EE9 RA7PPS 7:0 PPS[4:0]
0x0EEA RB0PPS 7:0 PPS[4:0]
0x0EEB RB1PPS 7:0 PPS[4:0]
0x0EEC RB2PPS 7:0 PPS[4:0]
0x0EED RB3PPS 7:0 PPS[4:0]
0x0EEE RB4PPS 7:0 PPS[4:0]
0x0EEF RB5PPS 7:0 PPS[4:0]
0x0EF0 RB6PPS 7:0 PPS[4:0]
0x0EF1 RB7PPS 7:0 PPS[4:0]
0x0EF2 RC0PPS 7:0 PPS[4:0]
0x0EF3 RC1PPS 7:0 PPS[4:0]
0x0EF4 RC2PPS 7:0 PPS[4:0]
0x0EF5 RC3PPS 7:0 PPS[4:0]
0x0EF6 RC4PPS 7:0 PPS[4:0]
0x0EF7 RC5PPS 7:0 PPS[4:0]
0x0EF8 RC6PPS 7:0 PPS[4:0]
0x0EF9 RC7PPS 7:0 PPS[4:0]
0x0EFA RD0PPS 7:0 PPS[4:0]
0x0EFB RD1PPS 7:0 PPS[4:0]
0x0EFC RD2PPS 7:0 PPS[4:0]
0x0EFD RD3PPS 7:0 PPS[4:0]
0x0EFE RD4PPS 7:0 PPS[4:0]
0x0EFF RD5PPS 7:0 PPS[4:0]
0x0F00 RD6PPS 7:0 PPS[4:0]
0x0F01 RD7PPS 7:0 PPS[4:0]
0x0F02 RE0PPS 7:0 PPS[4:0]
0x0F03 RE1PPS 7:0 PPS[4:0]
0x0F04 RE2PPS 7:0 PPS[4:0]
0x0F05 IOCAF 7:0 IOCAF7 IOCAF6 IOCAF5 IOCAF4 IOCAF3 IOCAF2 IOCAF1 IOCAF0
0x0F06 IOCAN 7:0 IOCAN7 IOCAN6 IOCAN5 IOCAN4 IOCAN3 IOCAN2 IOCAN1 IOCAN0
0x0F07 IOCAP 7:0 IOCAP7 IOCAP6 IOCAP5 IOCAP4 IOCAP3 IOCAP2 IOCAP1 IOCAP0
0x0F08 INLVLA 7:0 INLVLA7 INLVLA6 INLVLA5 INLVLA4 INLVLA3 INLVLA2 INLVLA1 INLVLA0
0x0F09 SLRCONA 7:0 SLRA7 SLRA6 SLRA5 SLRA4 SLRA3 SLRA2 SLRA1 SLRA0
0x0F0A ODCONA 7:0 ODCA7 ODCA6 ODCA5 ODCA4 ODCA3 ODCA2 ODCA1 ODCA0
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 655
...........continued
Address Name Bit Pos.
0x0F0B WPUA 7:0 WPUA7 WPUA6 WPUA5 WPUA4 WPUA3 WPUA2 WPUA1 WPUA0
0x0F0C ANSELA 7:0 ANSELA7 ANSELA6 ANSELA5 ANSELA4 ANSELA3 ANSELA2 ANSELA1 ANSELA0
0x0F0D IOCBF 7:0 IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0
0x0F0E IOCBN 7:0 IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0
0x0F0F IOCBP 7:0 IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0
0x0F10 INLVLB 7:0 INLVLB7 INLVLB6 INLVLB5 INLVLB4 INLVLB3 INLVLB2 INLVLB1 INLVLB0
0x0F11 SLRCONB 7:0 SLRB7 SLRB6 SLRB5 SLRB4 SLRB3 SLRB2 SLRB1 SLRB0
0x0F12 ODCONB 7:0 ODCB7 ODCB6 ODCB5 ODCB4 ODCB3 ODCB2 ODCB1 ODCB0
0x0F13 WPUB 7:0 WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0
0x0F14 ANSELB 7:0 ANSELB7 ANSELB6 ANSELB5 ANSELB4 ANSELB3 ANSELB2 ANSELB1 ANSELB0
0x0F15 IOCCF 7:0 IOCCF7 IOCCF6 IOCCF5 IOCCF4 IOCCF3 IOCCF2 IOCCF1 IOCCF0
0x0F16 IOCCN 7:0 IOCCN7 IOCCN6 IOCCN5 IOCCN4 IOCCN3 IOCCN2 IOCCN1 IOCCN0
0x0F17 IOCCP 7:0 IOCCP7 IOCCP6 IOCCP5 IOCCP4 IOCCP3 IOCCP2 IOCCP1 IOCCP0
0x0F18 INLVLC 7:0 INLVLC7 INLVLC6 INLVLC5 INLVLC4 INLVLC3 INLVLC2 INLVLC1 INLVLC0
0x0F19 SLRCONC 7:0 SLRC7 SLRC6 SLRC5 SLRC4 SLRC3 SLRC2 SLRC1 SLRC0
0x0F1A ODCONC 7:0 ODCC7 ODCC6 ODCC5 ODCC4 ODCC3 ODCC2 ODCC1 ODCC0
0x0F1B WPUC 7:0 WPUC7 WPUC6 WPUC5 WPUC4 WPUC3 WPUC2 WPUC1 WPUC0
0x0F1C ANSELC 7:0 ANSELC7 ANSELC6 ANSELC5 ANSELC4 ANSELC3 ANSELC2 ANSELC1 ANSELC0
0x0F1D INLVLD 7:0 INLVLD7 INLVLD6 INLVLD5 INLVLD4 INLVLD3 INLVLD2 INLVLD1 INLVLD0
0x0F1E SLRCOND 7:0 SLRD7 SLRD6 SLRD5 SLRD4 SLRD3 SLRD2 SLRD1 SLRD0
0x0F1F ODCOND 7:0 ODCD7 ODCD6 ODCD5 ODCD4 ODCD3 ODCD2 ODCD1 ODCD0
0x0F20 WPUD 7:0 WPUD7 WPUD6 WPUD5 WPUD4 WPUD3 WPUD2 WPUD1 WPUD0
0x0F21 ANSELD 7:0 ANSELD7 ANSELD6 ANSELD5 ANSELD4 ANSELD3 ANSELD2 ANSELD1 ANSELD0
0x0F22 IOCEF 7:0 IOCEF3
0x0F23 IOCEN 7:0 IOCEN3
0x0F24 IOCEP 7:0 IOCEP3
0x0F25 INLVLE 7:0 INLVLE3 INLVLE2 INLVLE1 INLVLE0
0x0F26 SLRCONE 7:0 SLRE2 SLRE1 SLRE0
0x0F27 ODCONE 7:0 ODCE2 ODCE1 ODCE0
0x0F28 WPUE 7:0 WPUE3 WPUE2 WPUE1 WPUE0
0x0F29 ANSELE 7:0 ANSELE2 ANSELE1 ANSELE0
0x0F2A HLVDCON0 7:0 EN OUT RDY INTH INTL
0x0F2B HLVDCON1 7:0 SEL[3:0]
0x0F2C FVRCON 7:0 FVREN FVRRDY TSEN TSRNG CDAFVR[1:0] ADFVR[1:0]
0x0F2D ZCDCON 7:0 SEN OUT POL INTP INTN
0x0F2E DAC1CON0 7:0 EN OE1 OE2 PSS[1:0] NSS
0x0F2F DAC1CON1 7:0 DAC1R[4:0]
0x0F30 CM2CON0 7:0 EN OUT POL HYS SYNC
0x0F31 CM2CON1 7:0 INTP INTN
0x0F32 CM2NCH 7:0 NCH[2:0]
0x0F33 CM2PCH 7:0 PCH[2:0]
0x0F34 CM1CON0 7:0 EN OUT POL HYS SYNC
0x0F35 CM1CON1 7:0 INTP INTN
0x0F36 CM1NCH 7:0 NCH[2:0]
0x0F37 CM1PCH 7:0 PCH[2:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 656
...........continued
Address Name Bit Pos.
0x0F38 CMOUT 7:0 MC2OUT MC1OUT
0x0F39 CLKRCON 7:0 EN DC[1:0] DIV[2:0]
0x0F3A CLKRCLK 7:0 CLK[3:0]
0x0F3B CWG1CLK 7:0 CS
0x0F3C CWG1ISM 7:0 ISM[3:0]
0x0F3D CWG1DBR 7:0 DBR[5:0]
0x0F3E CWG1DBF 7:0 DBF[5:0]
0x0F3F CWG1CON0 7:0 EN LD MODE[2:0]
0x0F40 CWG1CON1 7:0 IN POLD POLC POLB POLA
0x0F41 CWG1AS0 7:0 SHUTDOWN REN LSBD[1:0] LSAC[1:0]
0x0F42 CWG1AS1 7:0 AS7E AS6E AS5E AS4E AS3E AS2E AS1E AS0E
0x0F43 CWG1STR 7:0 OVRD OVRC OVRB OVRA STRD STRC STRB STRA
0x0F44 SCANLADR
7:0 SCANLADRL[7:0]
15:8 SCANLADRH[7:0]
23:16 SCANLADRU[5:0]
0x0F47 SCANHADR
7:0 SCANHADRL[7:0]
15:8 SCANHADRH[7:0]
23:16 SCANHADRU[5:0]
0x0F4A SCANCON0 7:0 SCANEN SCANGO BUSY INVALID INTM MODE[1:0]
0x0F4B SCANTRIG 7:0 TSEL[4:0]
0x0F4C MDCON0 7:0 EN OUT OPOL BIT
0x0F4D MDCON1 7:0 CHPOL CHSYNC CLPOL CLSYNC
0x0F4E MDSRC 7:0 SRCS[4:0]
0x0F4F MDCARL 7:0 CLS[3:0]
0x0F50 MDCARH 7:0 CHS[3:0]
0x0F51 ADACT 7:0 ADACT[4:0]
0x0F52 ADCLK 7:0 ADCS[5:0]
0x0F53 ADREF 7:0 ADNREF ADPREF[1:0]
0x0F54 ADCON1 7:0 ADPPOL ADIPEN ADGPOL ADDSEN
0x0F55 ADCON2 7:0 ADPSIS ADCRS[2:0] ADACLR ADMD[2:0]
0x0F56 ADCON3 7:0 ADCALC[2:0] ADSOI ADTMD[2:0]
0x0F57 ADACQ 7:0 ADACQ[7:0]
0x0F58 ADCAP 7:0 ADCAP[4:0]
0x0F59 ADPRE 7:0 ADPRE[7:0]
0x0F5A ADPCH 7:0 ADPCH[5:0]
0x0F5B ADCON0 7:0 ADON ADCONT ADCS ADFM ADGO
0x0F5C ADPREV
7:0 ADPREVL[7:0]
15:8 ADPREVH[7:0]
0x0F5E ADRES
7:0 ADRESL[7:0]
15:8 ADRESH[7:0]
0x0F60 ADSTAT 7:0 ADAOV ADUTHR ADLTHR ADMATH ADSTAT[2:0]
0x0F61 ADRPT 7:0 ADRPT[7:0]
0x0F62 ADCNT 7:0 ADCNT[7:0]
0x0F63 ADSTPT
7:0 ADSTPTL[7:0]
15:8 ADSTPTH[7:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 657
...........continued
Address Name Bit Pos.
0x0F65 ADLTH
7:0 ADLTHL[7:0]
15:8 ADLTHH[7:0]
0x0F67 ADUTH
7:0 ADUTHL[7:0]
15:8 ADUTHH[7:0]
0x0F69 ADERR
7:0 ADERRL[7:0]
15:8 ADERRH[7:0]
0x0F6B ADACC
7:0 ADACCL[7:0]
15:8 ADACCH[7:0]
0x0F6D ADFLTR
7:0 ADFLTRL[7:0]
15:8 ADFLTRH[7:0]
0x0F6F CRCDAT
7:0 CRCDATL[7:0]
15:8 CRCDATH[7:0]
0x0F71 CRCACC
7:0 CRCACCL[7:0]
15:8 CRCACCH[7:0]
0x0F73 CRCSHIFT
7:0 CRCSHIFTL[7:0]
15:8 CRCSHIFTH[7:0]
0x0F75 CRCXOR
7:0 CRCXORL[6:0] CRCXORL0
15:8 CRCXORH[7:0]
0x0F77 CRCCON0 7:0 EN GO BUSY ACCM SHIFTM FULL
0x0F78 CRCCON1 7:0 DLEN[3:0] PLEN[3:0]
0x0F79 NVMADR
7:0 NVMADRL[7:0]
15:8 NVMADRH[7:0]
23:16 NVMADRU[5:0]
0x0F7C NVMDAT
7:0 NVMDATL[7:0]
15:8 NVMDATH[7:0]
0x0F7E Reserved
0x0F7F NVMCON0 7:0 NVMEN NVMERR Reserved
0x0F80 NVMCON1 7:0 SECER SECWR WR SECRD RD
0x0F81 NVMCON2 7:0 NVMCON2[7:0]
0x0F82 LATA 7:0 LATA7 LATA6 LATA5 LATA4 LATA3 LATA2 LATA1 LATA0
0x0F83 LATB 7:0 LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0
0x0F84 LATC 7:0 LATC7 LATC6 LATC5 LATC4 LATC3 LATC2 LATC1 LATC0
0x0F85 LATD 7:0 LATD7 LATD6 LATD5 LATD4 LATD3 LATD2 LATD1 LATD0
0x0F86 LATE 7:0 LATE2 LATE1 LATE0
0x0F87 TRISA 7:0 TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0
0x0F88 TRISB 7:0 TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0
0x0F89 TRISC 7:0 TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
0x0F8A TRISD 7:0 TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0
0x0F8B TRISE 7:0 TRISE3 TRISE2 TRISE1 TRISE0
0x0F8C PORTA 7:0 RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0
0x0F8D PORTB 7:0 RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0
0x0F8E PORTC 7:0 RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0
0x0F8F PORTD 7:0 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
0x0F90 PORTE 7:0 RE3 RE2 RE1 RE0
0x0F91 SSP1BUF 7:0 BUF[7:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 658
...........continued
Address Name Bit Pos.
0x0F92 SSP1ADD 7:0 ADD[7:0]
0x0F93 SSP1MSK 7:0 MSK[6:0] MSK0
0x0F94 SSP1STAT 7:0 SMP CKE D/A P S R/W UA BF
0x0F95 SSP1CON1 7:0 WCOL SSPOV SSPEN CKP SSPM[3:0]
0x0F96 SSP1CON2 7:0 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
0x0F97 SSP1CON3 7:0 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
0x0F98 RC1REG 7:0 RCREG[7:0]
0x0F99 TX1REG 7:0 TXREG[7:0]
0x0F9A SP1BRG
7:0 SPBRGL[7:0]
15:8 SPBRGH[7:0]
0x0F9C RC1STA 7:0 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
0x0F9D TX1STA 7:0 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
0x0F9E BAUD1CON 7:0 ABDOVF RCIDL SCKP BRG16 WUE ABDEN
0x0F9F PWM4DC
7:0 DCL[1:0]
15:8 DCH[7:0]
0x0FA1 PWM4CON 7:0 EN OUT POL
0x0FA2 PWM3DC
7:0 DCL[1:0]
15:8 DCH[7:0]
0x0FA4 PWM3CON 7:0 EN OUT POL
0x0FA5 CCPR2
7:0 CCPRL[7:0]
15:8 CCPRH[7:0]
0x0FA7 CCP2CON 7:0 EN OUT FMT MODE[3:0]
0x0FA8 CCP2CAP 7:0 CTS[3:0]
0x0FA9 CCPR1
7:0 CCPRL[7:0]
15:8 CCPRH[7:0]
0x0FAB CCP1CON 7:0 EN OUT FMT MODE[3:0]
0x0FAC CCP1CAP 7:0 CTS[3:0]
0x0FAD CCPTMRS 7:0 P4TSEL[1:0] P3TSEL[1:0] C2TSEL[1:0] C1TSEL[1:0]
0x0FAD CCPTMRS 7:0 P4TSEL[1:0] P3TSEL[1:0] C2TSEL[1:0] C1TSEL[1:0]
0x0FAE T6TMR 7:0 TxTMR[7:0]
0x0FAF T6PR 7:0 TxPR[7:0]
0x0FB0 T6CON 7:0 ON CKPS[2:0] OUTPS[3:0]
0x0FB1 T6HLT 7:0 PSYNC CPOL CSYNC MODE[4:0]
0x0FB2 T6CLKCON 7:0 CS[4:0]
0x0FB3 T6RST 7:0 RSEL[4:0]
0x0FB4 T4TMR 7:0 TxTMR[7:0]
0x0FB5 T4PR 7:0 TxPR[7:0]
0x0FB6 T4CON 7:0 ON CKPS[2:0] OUTPS[3:0]
0x0FB7 T4HLT 7:0 PSYNC CPOL CSYNC MODE[4:0]
0x0FB8 T4CLKCON 7:0 CS[4:0]
0x0FB9 T4RST 7:0 RSEL[4:0]
0x0FBA T2TMR 7:0 TxTMR[7:0]
0x0FBB T2PR 7:0 TxPR[7:0]
0x0FBC T2CON 7:0 ON CKPS[2:0] OUTPS[3:0]
0x0FBD T2HLT 7:0 PSYNC CPOL CSYNC MODE[4:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 659
...........continued
Address Name Bit Pos.
0x0FBE T2CLKCON 7:0 CS[4:0]
0x0FBF T2RST 7:0 RSEL[4:0]
0x0FC0 TMR5
7:0 TMRxL[7:0]
15:8 TMRxH[7:0]
0x0FC2 T5CON 7:0 CKPS[1:0] SYNC RD16 ON
0x0FC3 T5GCON 7:0 GE GPOL GTM GSPM GGO/DONE GVAL
0x0FC4 TMR5GATE 7:0 GSS[4:0]
0x0FC5 TMR5CLK 7:0 CS[4:0]
0x0FC6 TMR3
7:0 TMRxL[7:0]
15:8 TMRxH[7:0]
0x0FC8 T3CON 7:0 CKPS[1:0] SYNC RD16 ON
0x0FC9 T3GCON 7:0 GE GPOL GTM GSPM GGO/DONE GVAL
0x0FCA TMR3GATE 7:0 GSS[4:0]
0x0FCB TMR3CLK 7:0 CS[4:0]
0x0FCC TMR1
7:0 TMRxL[7:0]
15:8 TMRxH[7:0]
0x0FCE T1CON 7:0 CKPS[1:0] SYNC RD16 ON
0x0FCF T1GCON 7:0 GE GPOL GTM GSPM GGO/DONE GVAL
0x0FD0 TMR1GATE 7:0 GSS[4:0]
0x0FD1 TMR1CLK 7:0 CS[4:0]
0x0FD2 TMR0L 7:0 TMR0L[7:0]
0x0FD3 TMR0H 7:0 TMR0H[7:0]
0x0FD4 T0CON0 7:0 T0EN T0OUT T016BIT T0OUTPS[3:0]
0x0FD5 T0CON1 7:0 T0CS[2:0] T0ASYNC T0CKPS[3:0]
0x0FD6 PCON1 7:0 RVREG RCM
0x0FD7 PCON0 7:0 STKOVF STKUNF WDTWV RWDT RMCLR RI POR BOR
0x0FD8 STATUS 7:0 TO PD N OV Z DC C
0x0FD9 FSR2
7:0 FSRL[7:0]
15:8 FSRH[3:0]
0x0FDB PLUSW2 7:0 PLUSW[7:0]
0x0FDC PREINC2 7:0 PREINC[7:0]
0x0FDD POSTDEC2 7:0 POSTDEC[7:0]
0x0FDE POSTINC2 7:0 POSTINC[7:0]
0x0FDF INDF2 7:0 INDF[7:0]
0x0FE0 BSR 7:0 BSR[3:0]
0x0FE1 FSR1
7:0 FSRL[7:0]
15:8 FSRH[3:0]
0x0FE3 PLUSW1 7:0 PLUSW[7:0]
0x0FE4 PREINC1 7:0 PREINC[7:0]
0x0FE5 POSTDEC1 7:0 POSTDEC[7:0]
0x0FE6 POSTINC1 7:0 POSTINC[7:0]
0x0FE7 INDF1 7:0 INDF[7:0]
0x0FE8 WREG 7:0 WREG[7:0]
0x0FE9 FSR0
7:0 FSRL[7:0]
15:8 FSRH[3:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 660
...........continued
Address Name Bit Pos.
0x0FEB PLUSW0 7:0 PLUSW[7:0]
0x0FEC PREINC0 7:0 PREINC[7:0]
0x0FED POSTDEC0 7:0 POSTDEC[7:0]
0x0FEE POSTINC0 7:0 POSTINC[7:0]
0x0FEF INDF0 7:0 INDF[7:0]
0x0FF0
...
0x0FF1
Reserved
0x0FF2 INTCON 7:0 GIE/GIEH PEIE/GIEL IPEN INT2EDG INT1EDG INT0EDG
0x0FF3 PROD
7:0 PRODL[7:0]
15:8 PRODH[7:0]
0x0FF5 TABLAT 7:0 TABLAT[7:0]
0x0FF6 TBLPTR
7:0 TBLPTRL[7:0]
15:8 TBLPTRH[7:0]
23:16 TBLPTR21 TBLPTRU[4:0]
0x0FF9 PCL 7:0 PCL[7:0]
0x0FFA PCLAT
7:0 PCLATH[7:0]
15:8 PCLATU[4:0]
0x0FFC STKPTR 7:0 STKPTR[4:0]
0x0FFD TOS
7:0 TOSL[7:0]
15:8 TOSH[7:0]
23:16 TOSU[4:0]
PIC18F26/45/46Q10
Register Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 661
36. In-Circuit Serial Programming (ICSP)
ICSP programming allows customers to manufacture circuit boards with unprogrammed devices.
Programming can be done after the assembly process, allowing the device to be programmed with the
most recent firmware or a custom firmware. Five pins are needed for ICSP programming:
ICSPCLK
ICSPDAT
MCLR/VPP
VDD
VSS
In Program/Verify mode the program memory, User IDs and the Configuration Words are programmed
through serial communications. The ICSPDAT pin is a bidirectional I/O used for transferring the serial
data and the ICSPCLK pin is the clock input. For more information on ICSP refer to the “ Memory
Programming Specification” (DS40001874).
36.1 High-Voltage Programming Entry Mode
The device is placed into High-Voltage Programming Entry mode by holding the ICSPCLK and ICSPDAT
pins low then raising the voltage on MCLR/VPP to VIHH.
36.2 Low-Voltage Programming Entry Mode
The Low-Voltage Programming Entry mode allows the PIC® Flash MCUs to be programmed using VDD
only, without high voltage. When the LVP bit of Configuration Words is set to ‘1’, the low-voltage ICSP
programming entry is enabled. To disable the Low-Voltage ICSP mode, the LVP bit must be programmed
to ‘0’.
Entry into the Low-Voltage Programming Entry mode requires the following steps:
1. MCLR is brought to Vil.
2. A 32-bit key sequence is presented on ICSPDAT, while clocking ICSPCLK.
Once the key sequence is complete, MCLR must be held at VIL for as long as Program/Verify mode is to
be maintained.
If low-voltage programming is enabled (LVP = 1), the MCLR Reset function is automatically enabled and
cannot be disabled. See the MCLR Section for more information.
The LVP bit can only be reprogrammed to ‘0’ by using the High-Voltage Programming mode.
Related Links
8.4 MCLR Reset
36.3 Common Programming Interfaces
Connection to a target device is typically done through an ICSP header. A commonly found connector
on development tools is the RJ-11 in the 6P6C (6-pin, 6-connector) configuration. See Figure 36-1.
PIC18F26/45/46Q10
In-Circuit Serial Programming (ICSP)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 662
Figure 36-1. ICD RJ-11 Style Connector Interface
1
2
3
4
5
6
Target
Bottom Side
PC Board
VPP/MCLR VSS
ICSPCLK
VDD
ICSPDAT
NC
Pin Description*
1 = VPP/MCLR
2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
5 = ICSPCLK
6 = No Connect
Another connector often found in use with the PICkit programmers is a standard 6-pin header with 0.1
inch spacing. Refer to Figure 36-2.
For additional interface recommendations, refer to the specific device programmer manual prior to PCB
design.
It is recommended that isolation devices be used to separate the programming pins from other circuitry.
The type of isolation is highly dependent on the specific application and may include devices such as
resistors, diodes, or even jumpers. See Figure 36-3 for more information.
Figure 36-2. PICkit Programmer Style Connector Interface
1
2
3
4
5
6
Pin 1 Indicator
Pin Description1
1 = VPP/MCLR
2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
PIC18F26/45/46Q10
In-Circuit Serial Programming (ICSP)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 663
5 = ICSPCLK
6 = No Connect
Note: 
1. Note:  The 6-pin header (0.100" spacing) accepts 0.025" square pins.
Figure 36-3. Typical Connection for ICSP Programming
VDD
VPP
VSS
External
Device to be
Data
Clock
VDD
MCLR/VPP
VSS
ICSPDAT
ICSPCLK
**
*
To Normal Connections
*Isolation devices (as required).
Programming
Signals Programmed
VDD
PIC18F26/45/46Q10
In-Circuit Serial Programming (ICSP)
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 664
37. Instruction Set Summary
PIC18F26/45/46Q10 devices incorporate the standard set of 75 PIC18 core instructions, as well as an
extended set of eight new instructions, for the optimization of code that is recursive or that utilizes a
software stack. The extended set is discussed later in this section.
37.1 Standard Instruction Set
The standard PIC18 instruction set adds many enhancements to the previous PIC® MCU instruction sets,
while maintaining an easy migration from these PIC® MCU instruction sets. Most instructions are a single
program memory word (16 bits), but there are four instructions that require two program memory
locations.
Each single-word instruction is a 16-bit word divided into an opcode, which specifies the instruction type
and one or more operands, which further specify the operation of the instruction.
The instruction set is highly orthogonal and is grouped into four basic categories:
Byte-oriented operations
Bit-oriented operations
Literal operations
Control operations
The PIC18 instruction set summary in Table 37-2 lists byte-oriented, bit-oriented, literal and control
operations. Table 37-1 shows the opcode field descriptions.
Most byte-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The destination of the result (specified by ‘d’)
3. The accessed memory (specified by ‘a’)
The file register designator ‘f’ specifies which file register is to be used by the instruction. The destination
designator ‘d’ specifies where the result of the operation is to be placed. If ‘d’ is zero, the result is placed
in the WREG register. If ‘d’ is one, the result is placed in the file register specified in the instruction.
All bit-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The bit in the file register (specified by ‘b’)
3. The accessed memory (specified by ‘a’)
The bit field designator ‘b’ selects the number of the bit affected by the operation, while the file register
designator ‘f’ represents the number of the file in which the bit is located.
The literal instructions may use some of the following operands:
A literal value to be loaded into a file register (specified by ‘k’)
The desired FSR register to load the literal value into (specified by ‘f’)
No operand required
(specified by ‘—’)
The control instructions may use some of the following operands:
A program memory address (specified by ‘n’)
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 665
The mode of the CALL or RETURN instructions
(specified by ‘s’)
The mode of the table read and table write instructions (specified by ‘m’)
No operand required
(specified by ‘—’)
All instructions are a single word, except for four double-word instructions. These instructions were made
double-word to contain the required information in 32 bits. In the second word, the four MSbs are ‘1’s. If
this second word is executed as an instruction (by itself), it will execute as a NOP.
All single-word instructions are executed in a single instruction cycle, unless a conditional test is true or
the Program Counter is changed as a result of the instruction. In these cases, the execution takes two
instruction cycles, with the additional instruction cycle(s) executed as a NOP.
The double-word instructions execute in two instruction cycles.
One instruction cycle consists of four oscillator periods. Thus, for an oscillator frequency of 4 MHz, the
normal instruction execution time is 1 μs. If a conditional test is true, or the Program Counter is changed
as a result of an instruction, the instruction execution time is 2 μs. Two-word branch instructions (if true)
would take 3 μs.
Figure 37-1 shows the general formats that the instructions can have. All examples use the convention
‘nnh’ to represent a hexadecimal number.
The Instruction Set Summary, shown in Table 37-2, lists the standard instructions recognized by the
Microchip Assembler (MPASMTM).
37.1.1 Standard Instruction Set
provides a description of each instruction.
Table 37-1. Opcode Field Descriptions
Field Description
aRAM access bit
a = 0: RAM location in Access RAM (BSR register is ignored)
a = 1: RAM bank is specified by BSR register
bbb Bit address within an 8-bit file register (0 to 7).
BSR Bank Select Register. Used to select the current RAM bank.
C, DC, Z, OV, N ALU Status bits: Carry, Digit Carry, Zero, Overflow, Negative.
dDestination select bit
d = 0: store result in WREG
d = 1: store result in file register f
dest Destination: either the WREG register or the specified register file location.
f8-bit Register file address (00h to FFh) or 2-bit FSR designator (0h to 3h).
fs12-bit Register file address (000h to FFFh). This is the source address.
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 666
...........continued
Field Description
fd12-bit Register file address (000h to FFFh). This is the destination address.
GIE Global Interrupt Enable bit.
kLiteral field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value).
label Label name.
mm The mode of the TBLPTR register for the table read and table write instructions.
Only used with table read and table write instructions:
* No change to register (such as TBLPTR with table reads and writes)
*+ Post-Increment register (such as TBLPTR with table reads and writes)
*- Post-Decrement register (such as TBLPTR with table reads and writes)
+* Pre-Increment register (such as TBLPTR with table reads and writes)
nThe relative address (2’s complement number) for relative branch instructions or
the direct address for
CALL/BRANCH and RETURN instructions.
PC Program Counter.
PCL Program Counter Low Byte.
PCH Program Counter High Byte.
PCLATH Program Counter High Byte Latch.
PCLATU Program Counter Upper Byte Latch.
PD Power-down bit.
PRODH Product of Multiply High Byte.
PRODL Product of Multiply Low Byte.
sFast Call/Return mode select bit
s = 0: do not update into/from shadow registers
s = 1: certain registers loaded into/from shadow registers (Fast mode)
TBLPTR 21-bit Table Pointer (points to a Program Memory location).
TABLAT 8-bit Table Latch.
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 667
...........continued
Field Description
TO Time-out bit.
TOS Top-of-Stack.
uUnused or unchanged.
WDT Watchdog Timer.
WREG Working register (accumulator).
xDon’t care (‘0’ or ‘1’). The assembler will generate code with x = 0. It is the
recommended form of use for compatibility with all Microchip software tools.
zs7-bit offset value for Indirect Addressing of register files (source).
zd7-bit offset value for Indirect Addressing of register files (destination).
{ } Optional argument.
[text] Indicates an indexed address.
(text) The contents of text.
[expr]<n> Specifies bit n of the register indicated by the pointer expr.
Assigned to.
< > Register bit field.
In the set of.
italics User defined term (font is Courier).
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 668
Figure 37-1. General Format for Instructions
Byte-oriented file register operations
15 10 9 8 7 0
d = 0for result destination to be WREG register
OPCODE d a f (FILE #)
d = 1for result destination to be file register (f)
a = 0to force Access Bank
Bit-oriented file register operations
15 12 11 9 8 7 0
OPCODE b (BIT #) a f (FILE #)
b = 3-bit position of bit in file register (f)
Literal operations
15 8 7 0
OPCODE k (liter al )
k = 8-bit immediate value
Byte to Byte move operations (2-word)
15 12 11 0
OPCODE f (Source FILE #)
CALL,GOTO and Branch operations
15 8 7 0
OPCODE n<7:0> (literal)
n = 20-bit immediate value
a = 1for BSR to select bank
f = 8-bit file register address
a = 0to force Access Bank
a = 1for BSR to select bank
f = 8-bit file register address
15 12 11 0
1111 n<19:8> (literal)
15 12 11 0
1111 f (Destination FILE #)
f = 12-bit file register address
Control operations
Example Instruction
ADDWF MYREG, W, B
MOVFF MYREG1, MYREG2
BSF MYREG, bit, B
MOVLW 7Fh
GOTO Label
15 8 7 0
OPCODE n<7:0> (literal)
15 12 11 0
1111 n<19:8> (literal)
CALL MYFUNC
15 11 10 0
OP CODE n <10: 0> (liter al )
S = Fast bit
BRA MYFUNC
15 8 7 0
OPCODE n<7:0> (literal) BC MYFUNC
S
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 669
Table 37-2. Instruction Set
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
BYTE-ORIENTED OPERATIONS
ADDWF f, d,
a
Add WREG and f 1 0010 01da ffff ffff C, DC, Z,
OV, N
1, 2
ADDWFC f, d,
a
Add WREG and
CARRY bit to f
10010 00da ffff ffff C, DC, Z,
OV, N
1, 2
ANDWF f, d,
a
AND WREG with f 1 0001 01da ffff ffff Z, N 1, 2
CLRF f, a Clear f 1 0110 101a ffff ffff Z 2
COMF f, d,
a
Complement f 1 0001 11da ffff ffff Z, N 1, 2
CPFSEQ f, a Compare f with
WREG, skip =
1 (2 or 3) 0110 001a ffff ffff None 4
CPFSGT f, a Compare f with
WREG, skip >
1 (2 or 3) 0110 010a ffff ffff None 4
CPFSLT f, a Compare f with
WREG, skip <
1 (2 or 3) 0110 000a ffff ffff None 1, 2
DECF f, d,
a
Decrement f 1 0000 01da ffff ffff C, DC, Z,
OV, N
1, 2, 3,
4
DECFSZ f, d,
a
Decrement f, Skip if
0
1 (2 or 3) 0010 11da ffff ffff None 1, 2, 3,
4
DCFSNZ f, d,
a
Decrement f, Skip if
Not 0
1 (2 or 3) 0100 11da ffff ffff None 1, 2
INCF f, d,
a
Increment f 1 0010 10da ffff ffff C, DC, Z,
OV, N
1, 2, 3,
4
INCFSZ f, d,
a
Increment f, Skip if
0
1 (2 or 3) 0011 11da ffff ffff None 4
INFSNZ f, d,
a
Increment f, Skip if
Not 0
1 (2 or 3) 0100 11da ffff ffff None 1, 2
IORWF f, d,
a
Inclusive OR
WREG with f
10001 00da ffff ffff Z, N 1, 2
MOVF f, d,
a
Move f 1 0101 00da ffff ffff Z, N 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 670
...........continued
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
MOVFF fs, fdMove fs (source) to
1st word
21100 ffff ffff ffff None
fd (destination) 2nd
word
1111 ffff ffff ffff
MOVWF f, a Move WREG to f 1 0110 111a ffff ffff None
MULWF f, a Multiply WREG
with f
10000 001a ffff ffff None 1, 2
NEGF f, a Negate f 1 0110 110a ffff ffff C, DC, Z,
OV, N
RLCF f, d,
a
Rotate Left f
through Carry
10011 01da ffff ffff C, Z, N 1, 2
RLNCF f, d,
a
Rotate Left f (No
Carry)
10100 01da ffff ffff Z, N
RRCF f, d,
a
Rotate Right f
through Carry
10011 00da ffff ffff C, Z, N
RRNCF f, d,
a
Rotate Right f (No
Carry)
10100 00da ffff ffff Z, N
SETF f, a Set f 1 0110 00da ffff ffff None 1, 2
SUBFWB f, d,
a
Subtract f from
WREG with
borrow
10101 01da ffff ffff C, DC, Z,
OV, N
SUBWF f, d,
a
Subtract WREG
from f
10101 11da ffff ffff C, DC, Z,
OV, N
1, 2
SUBWFB f, d,
a
Subtract WREG
from f with
borrow
10101 10da ffff ffff C, DC, Z,
OV, N
SWAPF f, d,
a
Swap nibbles in f 1 0011 10da ffff ffff None 4
TSTFSZ f, a Test f, skip if 0 1 (2 or 3) 0110 011a ffff ffff None 1, 2
XORWF f, d,
a
Exclusive OR
WREG with f
10001 10da ffff ffff Z, N
BIT-ORIENTED OPERATIONS
BCF f, b,
a
Bit Clear f 1 1001 bbba ffff ffff None 1, 2
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 671
...........continued
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
BSF f, b,
a
Bit Set f 1 1000 bbba ffff ffff None 1, 2
BTFSC f, b,
a
Bit Test f, Skip if
Clear
1 (2 or 3) 1011 bbba ffff ffff None 3, 4
BTFSS f, b,
a
Bit Test f, Skip if
Set
1 (2 or 3) 1010 bbba ffff ffff None 3, 4
BTG f, b,
a
Bit Toggle f 1 0111 bbba ffff ffff None 1, 2
CONTROL OPERATIONS
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 672
...........continued
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
BC n Branch if Carry 1 (2) 1110 0010 nnnn nnnn None 4
BN n Branch if Negative 1 (2) 1110 0110 nnnn nnnn None
BNC n Branch if Not Carry 1 (2) 1110 0011 nnnn nnnn None
BNN n Branch if Not
Negative
1 (2) 1110 0111 nnnn nnnn None
BNOV n Branch if Not
Overflow
1 (2) 1110 0101 nnnn nnnn None
BNZ n Branch if Not Zero 1 (2) 1110 0001 nnnn nnnn None
BOV n Branch if Overflow 1 (2) 1110 0100 nnnn nnnn None
BRA n Branch
Unconditionally
21101 0nnn nnnn nnnn None
BZ n Branch if Zero 1 (2) 1110 0000 nnnn nnnn None
CALL k, s Call
subroutine 1st word
21110 110s kkkk kkkk None
2nd word 1111 kkkk kkkk kkkk
CLRWDT Clear Watchdog
Timer
10000 0000 0000 0100 TO, PD
DAW Decimal Adjust
WREG
10000 0000 0000 0111 C
GOTO k Go to address 1st
word
21110 1111 kkkk kkkk None
2nd word 1111 kkkk kkkk kkkk
NOP No Operation 1 0000 0000 0000 0000 None
NOP No Operation 1 1111 xxxx xxxx xxxx None
POP Pop top of return
stack (TOS)
10000 0000 0000 0110 None
PUSH Push top of return
stack (TOS)
10000 0000 0000 0101 None
RCALL n Relative Call 2 1101 1nnn nnnn nnnn None
RESET Software device
Reset
10000 0000 1111 1111 All
RETFIE s Return from
interrupt enable
20000 0000 0001 000s GIE/GIEH,
PEIE/GIEL
RETLW k Return with literal in
WREG
20000 1100 kkkk kkkk None
RETURN s Return from
Subroutine
20000 0000 0001 001s None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 673
...........continued
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
SLEEP Go into Standby
mode
10000 0000 0000 0011 TO, PD
LITERAL OPERATIONS
ADDLW k Add literal and
WREG
10000 1111 kkkk kkkk C, DC, Z,
OV, N
ANDLW k AND literal with
WREG
10000 1011 kkkk kkkk Z, N
IORLW k Inclusive OR literal
with WREG
10000 1001 kkkk kkkk Z, N
LFSR f, k Move literal (12-bit)
2nd word
21110 1110 00ff kkkk None
to FSR(f) 1st word 1111 0000 kkkk kkkk
MOVLB k Move literal to
BSR<3:0>
10000 0001 0000 kkkk None
MOVLW k Move literal to
WREG
10000 1110 kkkk kkkk None
MULLW k Multiply literal with
WREG
10000 1101 kkkk kkkk None
RETLW k Return with literal in
WREG
20000 1100 kkkk kkkk None
SUBLW k Subtract WREG
from literal
10000 1000 kkkk kkkk C, DC, Z,
OV, N
XORLW k Exclusive OR literal
with WREG
10000 1010 kkkk kkkk Z, N
DATA MEMORY ↔ PROGRAM MEMORY OPERATIONS
TBLRD* Table Read 2 0000 0000 0000 1000 None
TBLRD*+ Table Read with
post-increment
0000 0000 0000 1001 None
TBLRD*- Table Read with
post-decrement
0000 0000 0000 1010 None
TBLRD+* Table Read with
pre-increment
0000 0000 0000 1011 None
TBLWT* Table Write 2 0000 0000 0000 1100 None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 674
...........continued
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
TBLWT*+ Table Write with
post-increment
0000 0000 0000 1101 None
TBLWT*- Table Write with
post-decrement
0000 0000 0000 1110 None
TBLWT+* Table Write with
pre-increment
0000 0000 0000 1111 None
Note: 
1. When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used
will be that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin
configured as input and is driven low by an external device, the data will be written back with a ‘0’.
2. If this instruction is executed on the TMR0 register (and where applicable, ‘d’ = 1), the prescaler will
be cleared if assigned.
3. If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles.
The second cycle is executed as a NOP.
4. Some instructions are two-word instructions. The second word of these instructions will be
executed as a NOP unless the first word of the instruction retrieves the information embedded in
these 16 bits. This ensures that all program memory locations have a valid instruction.
37.1.1 Standard Instruction Set
ADDLW ADD literal to W
Syntax: ADDLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) + k → W
Status Affected: N, OV, C, DC, Z
Encoding: 0000 1111 kkkk kkkk
Description: The contents of W are added to the
8-bit literal ‘k’ and the result is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write to W
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 675
Example: ADDLW 15h
Before Instruction
W = 10h
After Instruction
W = 25h
ADDWF ADD W to f
Syntax: ADDWF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (W) + (f) → dest
Status
Affected:
N, OV, C, DC, Z
Encoding: 0010 01da ffff ffff
Description: Add W to register ‘f’. If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored
back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: ADDWF REG, 0, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 676
Before Instruction
W = 17h
REG = 0C2h
After Instruction
W = 0D9h
REG = 0C2h
Important:  All PIC18 instructions may take an optional label argument preceding the
instruction mnemonic for use in symbolic addressing. If a label is used, the instruction format
then becomes: {label} instruction argument(s).
ADDWFC ADD W and CARRY bit to f
Syntax: ADDWFC f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (W) + (f) + (C) → dest
Status
Affected:
N,OV, C, DC, Z
Encoding: 0010 00da ffff ffff
Description: Add W, the CARRY flag and data memory location ‘f’. If ‘d’ is ‘0’, the result is placed in W.
If ‘d’ is ‘1’, the result is placed in data memory location ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh).See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: ADDWFC REG, 0, 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 677
Before Instruction
CARRY bit = 1
REG = 02h
W = 4Dh
After Instruction
CARRY bit = 0
REG = 02h
W = 50h
ANDLW AND literal with W
Syntax: ANDLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .AND. k → W
Status Affected: N, Z
Encoding: 0000 1011 kkkk kkkk
Description: The contents of W are AND’ed with the 8-bit literal ‘k’. The result is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal ‘k’ Process Data Write to W
Example: ANDLW 05Fh
Before Instruction
W = A3h
After Instruction
W = 03h
ANDWF AND W with f
Syntax: ANDWF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (W) .AND. (f) → dest
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 678
...........continued
ANDWF AND W with f
Status
Affected:
N, Z
Encoding: 0001 01da ffff ffff
Description: The contents of W are AND’ed with
register ‘f’. If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored back in
register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: ANDWF REG, 0, 0
Before Instruction
W = 17h
REG = C2h
After Instruction
W = 02h
REG = C2h
BC Branch if Carry
Syntax: BC n
Operands: -128 ≤ n ≤ 127
Operation: if CARRY bit is ‘1’
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1110 0010 nnnn nnnn
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 679
...........continued
BC Branch if Carry
Description: If the CARRY bit is ‘1’, then the program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BC 5
Before Instruction
PC = address (HERE)
After Instruction
If CARRY = 1;
PC = address (HERE + 12)
If CARRY = 0;
PC = address (HERE + 2)
BCF Bit Clear f
Syntax: BCF f, b {,a}
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a [0,1]
Operation: 0 → f<b>
Status
Affected:
None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 680
...........continued
BCF Bit Clear f
Encoding: 1001 bbba ffff ffff
Description: Bit ‘b’ in register ‘f’ is cleared.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
Example: BCF FLAG_REG, 7, 0
Before Instruction
FLAG_REG = C7h
After Instruction
FLAG_REG = 47h
BN Branch if Negative
Syntax: BN n
Operands: -128 ≤ n ≤ 127
Operation: if NEGATIVE bit is ‘1’
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1110 0110 nnnn nnnn
Description: If the NEGATIVE bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 681
...........continued
BN Branch if Negative
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BN Jump
Before Instruction
PC = address (HERE)
After Instruction
If NEGATIVE = 1;
PC = address (Jump)
If NEGATIVE = 0;
PC = address (HERE + 2)
BNC Branch if Not Carry
Syntax: BNC n
Operands: -128 ≤ n ≤ 127
Operation: if CARRY bit is ‘0’
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1110 0011 nnnn nnnn
Description: If the CARRY bit is ‘0’, then the program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 682
...........continued
BNC Branch if Not Carry
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BNC Jump
Before Instruction
PC = address (HERE)
After Instruction
If CARRY = 0;
PC = address (Jump)
If CARRY = 1;
PC = address (HERE + 2)
BNN Branch if Not Negative
Syntax: BNN n
Operands: -128 ≤ n ≤ 127
Operation: if NEGATIVE bit is ‘0’
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1110 0111 nnnn nnnn
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 683
...........continued
BNN Branch if Not Negative
Description: If the NEGATIVE bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BNN Jump
Before Instruction
PC = address (HERE)
After Instruction
If NEGATIVE = 0;
PC = address (Jump)
If NEGATIVE = 1;
PC = address (HERE + 2)
BNOV Branch if Not Overflow
Syntax: BNOV n
Operands: -128 ≤ n ≤ 127
Operation: if OVERFLOW bit is ‘0’
(PC) + 2 + 2n → PC
Status
Affected:
None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 684
...........continued
BNOV Branch if Not Overflow
Encoding: 1110 0101 nnnn nnnn
Description: If the OVERFLOW bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BNOV Jump
Before Instruction
PC = address (HERE)
After Instruction
If OVERFLOW = 0;
PC = address (Jump)
If OVERFLOW = 1;
PC = address (HERE + 2)
BNZ Branch if Not Zero
Syntax: BNZ n
Operands: -128 ≤ n ≤ 127
Operation: if ZERO bit is ‘0’
(PC) + 2 + 2n → PC
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 685
...........continued
BNZ Branch if Not Zero
Status
Affected:
None
Encoding: 1110 0001 nnnn nnnn
Description: If the ZERO bit is ‘0’, then the program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BNZ Jump
Before Instruction
PC = address (HERE)
After Instruction
If ZERO = 0;
PC = address (Jump)
If ZERO = 1;
PC = address (HERE + 2)
BRA Unconditional Branch
Syntax: BRA n
Operands: -1024 ≤ n ≤ 1023
Operation: (PC) + 2 + 2n → PC
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 686
...........continued
BRA Unconditional Branch
Status
Affected:
None
Encoding: 1101 0nnn nnnn nnnn
Description: Add the 2’s complement number ‘2n’ to the PC. Since the PC will have incremented to
fetch the next instruction, the new address will be PC + 2 + 2n. This instruction is a 2-
cycle instruction.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE BRA Jump
Before Instruction
PC = address (HERE)
After Instruction
PC = address (Jump)
BSF Bit Set f
Syntax: BSF f, b {,a}
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a [0,1]
Operation: 1 → f<b>
Status
Affected:
None
Encoding: 1000 bbba ffff ffff
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 687
...........continued
BSF Bit Set f
Description: Bit ‘b’ in register ‘f’ is set.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
Example: BSF FLAG_REG, 7, 1
Before Instruction
FLAG_REG = 0Ah
After Instruction
FLAG_REG = 8Ah
BTFSC Bit Test File, Skip if Clear
Syntax: BTFSC f, b {,a}
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a [0,1]
Operation: skip if (f<b>) = 0
Status
Affected:
None
Encoding: 1011 bbba ffff ffff
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 688
...........continued
BTFSC Bit Test File, Skip if Clear
Description: If bit ‘b’ in register ‘f’ is ‘0’, then the next instruction is skipped. If bit ‘b’ is ‘0’, then the next
instruction fetched during the current instruction execution is discarded and a NOP is
executed instead, making this a 2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh).
See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE
FALSE
TRUE
BTFSC
:
:
FLAG, 1, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 689
Before Instruction
PC = address (HERE)
After Instruction
If FLAG<1> = 0;
PC = address (TRUE)
If FLAG<1> = 1;
PC = address (FALSE)
BTFSS Bit Test File, Skip if Set
Syntax: BTFSS f, b {,a}
Operands: 0 ≤ f ≤ 255
0 ≤ b < 7
a [0,1]
Operation: skip if (f<b>) = 1
Status
Affected:
None
Encoding: 1010 bbba ffff ffff
Description: If bit ‘b’ in register ‘f’ is ‘1’, then the next instruction is skipped. If bit ‘b’ is ‘1’, then the next
instruction fetched during the current instruction execution is discarded and a NOP is
executed instead, making this a 2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates
in Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh).
See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 690
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE
FALSE
TRUE
BTFSS
:
:
FLAG, 1, 0
Before Instruction
PC = address (HERE)
After Instruction
If FLAG<1> = 0;
PC = address (FALSE)
If FLAG<1> = 1;
PC = address (TRUE)
BTG Bit Toggle f
Syntax: BTG f, b {,a}
Operands: 0 ≤ f ≤ 255
0 ≤ b < 7
a [0,1]
Operation: (f<b>) → f<b>
Status
Affected:
None
Encoding: 0111 bbba ffff ffff
Description: Bit ‘b’ in data memory location ‘f’ is inverted.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 691
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
Example: BTG PORTC, 4, 0
Before Instruction:
PORTC = 0111 0101 [75h]
After Instruction:
PORTC = 0110 0101 [65h]
BOV Branch if Overflow
Syntax: BOV n
Operands: -128 ≤ n ≤ 127
Operation: if OVERFLOW bit is ‘1’
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1110 0100 nnnn nnnn
Description: If the OVERFLOW bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be PC + 2 + 2n. This instruction is then a 2-cycle
instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 692
Decode Read literal ‘n’ Process Data No
operation
Example: HERE BOV Jump
Before Instruction
PC = address (HERE)
After Instruction
If OVERFLOW = 1;
PC = address (Jump)
If OVERFLOW = 0;
PC = address (HERE + 2)
BZ Branch if Zero
Syntax: BZ n
Operands: -128 ≤ n ≤ 127
Operation: if ZERO bit is ‘1’
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1110 0000 nnnn nnnn
Description: If the ZERO bit is ‘1’, then the program will branch.
The 2’s complement number ‘2n’ is added to the PC. Since the PC will
have incremented to fetch the next instruction, the new address will be PC + 2 + 2n.
This instruction is then a 2-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’ Process Data No
operation
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 693
Example: HERE BZ Jump
Before Instruction
PC = address (HERE)
After Instruction
If ZERO = 1;
PC = address (Jump)
If ZERO = 0;
PC = address (HERE + 2)
CALL Subroutine Call
Syntax: CALL k {,s}
Operands: 0 ≤ k ≤ 1048575
s [0,1]
Operation: (PC) + 4 → TOS,
k → PC<20:1>,
if s = 1
(W) → WS,
(Status) → STATUSS,
(BSR) → BSRS
Status Affected: None
Encoding:
1st word
(k<7:0>)
2nd
word(k<19:8>)
1110
1111
110s
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
Description: Subroutine call of entire 2-Mbyte
memory range. First, return address (PC + 4) is pushed onto the return stack. If ‘s’ =
1, the W, Status and BSR
registers are also pushed into their respective shadow registers, WS, STATUSS and
BSRS. If ‘s’ = 0, no update occurs (default). Then, the
20-bit value ‘k’ is loaded into PC<20:1>. CALL is a 2-cycle instruction.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal ‘k’<7:0>, PUSH PC to stack Read literal ‘k’<19:8>, Write to PC
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 694
No
operation
No
operation
No
operation
No
operation
Example: HERE CALL THERE, 1
Before Instruction
PC = address (HERE)
After Instruction
PC = address (THERE)
TOS = address (HERE + 4)
WS = W
BSRS = BSR
STATUSS = Status
CLRF Clear f
Syntax: CLRF f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: 000h → f
1 → Z
Status
Affected:
Z
Encoding: 0110 101a ffff ffff
Description: Clears the contents of the specified
register.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 695
Example: CLRF FLAG_REG, 1
Before Instruction
FLAG_REG = 5Ah
After Instruction
FLAG_REG = 00h
CLRWDT Clear Watchdog Timer
Syntax: CLRWDT
Operands: None
Operation: 000h → WDT,
000h → WDT postscaler,
1 → TO,
1 → PD
Status Affected: TO, PD
Encoding: 0000 0000 0000 0100
Description: CLRWDT instruction resets the
Watchdog Timer. It also resets the postscaler of the WDT. Status bits, TO and PD, are
set.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
No
operation
Example: CLRWDT
Before Instruction
WDT Counter = ?
After Instruction
WDT Counter = 00h
WDT Postscaler = 0
TO = 1
PD = 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 696
COMF Complement f
Syntax: COMF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) → dest
Status
Affected:
N, Z
Encoding: 0001 11da ffff ffff
Description: The contents of register ‘f’ are
complemented. If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored back in
register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: COMF REG, 0, 0
Before Instruction
REG = 13h
After Instruction
REG = 13h
W = ECh
CPFSEQ Compare f with W, skip if f = W
Syntax: CPFSEQ f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 697
...........continued
CPFSEQ Compare f with W, skip if f = W
Operation: (f) – (W),
skip if (f) = (W)
(unsigned comparison)
Status
Affected:
None
Encoding: 0110 001a ffff ffff
Description: Compares the contents of data memory location ‘f’ to the contents of W by
performing an unsigned subtraction.
If ‘f’ = W, then the fetched instruction is discarded and a NOP is executed instead, making
this a 2-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 698
Example: HERE CPFSEQ REG, 0
NEQUAL :
EQUAL :
Before Instruction
PC Address = HERE
W = ?
REG = ?
After Instruction
If REG = W;
PC = Address (EQUAL)
If REG ≠ ;
PC = Address (NEQUAL)
CPFSGT Compare f with W, skip if f > W
Syntax: CPFSGT f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: (f) – (),
skip if (f) > (W)
(unsigned comparison)
Status
Affected:
None
Encoding: 0110 010a ffff ffff
Description: Compares the contents of data memory location ‘f’ to the contents of the W by
performing an unsigned subtraction.
If the contents of ‘f’ are greater than the contents of WREG, then the fetched instruction
is discarded and a NOP is executed instead, making this a
2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 699
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSGT REG, 0
NGREATER :
GREATER :
Before Instruction
PC = Address (HERE)
W = ?
After Instruction
If REG > W;
PC = Address (GREATER)
If REG ≤ W;
PC = Address (NGREATER)
CPFSLT Compare f with W, skip if f < W
Syntax: CPFSLT f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: (f) – (),
skip if (f) < (W)
(unsigned comparison)
Status
Affected:
None
Encoding: 0110 000a ffff ffff
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 700
...........continued
CPFSLT Compare f with W, skip if f < W
Description: Compares the contents of data memory location ‘f’ to the contents of W by
performing an unsigned subtraction.
If the contents of ‘f’ are less than the contents of W, then the fetched
instruction is discarded and a NOP is executed instead, making this a
2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSLT REG, 1
NLESS :
LESS :
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 701
Before Instruction
PC = Address (HERE)
W = ?
After Instruction
If REG < W;
PC = Address (LESS)
If REG ≥ W;
PC = Address (NLESS)
DAW Decimal Adjust W Register
Syntax: DAW
Operands: None
Operation: If [W<3:0> > 9] or [DC = 1] then
(W<3:0>) + 6 → W<3:0>;
else
(W<3:0>) → W<3:0>;
If [W<7:4> + DC > 9] or [C = 1] then
(W<7:4>) + 6 + DC → W<7:4> ;
else
(W<7:4>) + DC → W<7:4>
Status
Affected:
C
Encoding: 0000 0000 0000 0111
Description: DAW adjusts the 8-bit value in W, resulting from the earlier addition of two variables
(each in packed BCD format) and produces a correct packed BCD result.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register W
Process Data Write
W
Example1: DAW
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 702
Before Instruction
W = A5h
C = 0
DC = 0
After Instruction
W = 05h
C = 1
DC = 0
Example 2:
Before Instruction
W = CEh
C = 0
DC = 0
After Instruction
W = 34h
C = 1
DC = 0
DECF Decrement f
Syntax: DECF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) – 1 → dest
Status
Affected:
C, DC, N, OV, Z
Encoding: 0000 01da ffff ffff
Description: Decrement register ‘f’. If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored
back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 703
...........continued
DECF Decrement f
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: DECF CNT, 1, 0
Before Instruction
CNT = 01h
Z = 0
After Instruction
CNT = 00h
Z = 1
DECFSZ Decrement f, skip if 0
Syntax: DECFSZ f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) – 1 → dest,
skip if result = 0
Status
Affected:
None
Encoding: 0010 11da ffff ffff
Description: The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default).
If the result is ‘0’, the next instruction, which is already fetched, is discarded and a NOP is
executed instead, making it a 2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 704
...........continued
DECFSZ Decrement f, skip if 0
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE DECFSZ CNT, 1, 1
GOTO LOOP
CONTINUE
Before Instruction
PC = Address (HERE)
After Instruction
CNT = CNT - 1
If CNT = 0;
PC = Address (CONTINUE)
If CNT ≠ 0;
PC = Address (HERE + 2)
DCFSNZ Decrement f, skip if not 0
Syntax: DCFSNZ f {,d {,a}}
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 705
...........continued
DCFSNZ Decrement f, skip if not 0
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) – 1 → dest,
skip if result ≠ 0
Status
Affected:
None
Encoding: 0100 11da ffff ffff
Description: The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default).
If the result is not ‘0’, the next
instruction, which is already fetched, is discarded and a NOP is executed instead, making
it a 2-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 706
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE DCFSNZ TEMP, 1, 0
ZERO :
NZERO :
Before Instruction
TEMP = ?
After Instruction
TEMP = TEMP – 1,
If TEMP = 0;
PC = Address (ZERO)
If TEMP ≠ 0;
PC = Address (NZERO)
GOTO Unconditional Branch
Syntax: GOTO k
Operands: 0 ≤ k ≤ 1048575
Operation: k → PC<20:1>
Status Affected: None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
1110
1111
1111
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
Description: GOTO allows an unconditional branch anywhere within entire
2-Mbyte memory range. The 20-bit value ‘k’ is loaded into PC<20:1>. GOTO is
always a 2-cycle
instruction.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal ‘k’<7:0>, No
operation
Read literal ‘k’<19:8>, Write to PC
No
operation
No
operation
No
operation
No
operation
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 707
Example: GOTO THERE
After Instruction
PC = Address (THERE)
INCF Increment f
Syntax: INCF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) + 1 → dest
Status
Affected:
C, DC, N, OV, Z
Encoding: 0010 10da ffff ffff
Description: The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: INCF CNT, 1, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 708
Before Instruction
CNT = FFh
Z = 0
C = ?
DC = ?
After Instruction
CNT = 00h
Z = 1
C = 1
DC = 1
INCFSZ Increment f, skip if 0
Syntax: INCFSZ f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) + 1 → dest,
skip if result = 0
Status
Affected:
None
Encoding: 0011 11da ffff ffff
Description: The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default).
If the result is ‘0’, the next instruction, which is already fetched, is discarded and a NOP is
executed instead, making it a 2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 709
Decode Read
register ‘f’
Process Data Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE INCFSZ CNT, 1, 0
NZERO :
ZERO :
Before Instruction
PC = Address (HERE)
After Instruction
CNT = CNT + 1
If CNT = 0;
PC = Address (ZERO)
If CNT ≠ 0;
PC = Address (NZERO)
INFSNZ Increment f, skip if not 0
Syntax: INFSNZ f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) + 1 → dest,
skip if result ≠ 0
Status
Affected:
None
Encoding: 0100 10da ffff ffff
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 710
...........continued
INFSNZ Increment f, skip if not 0
Description: The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default).
If the result is not ‘0’, the next
instruction, which is already fetched, is discarded and a NOP is executed instead, making
it a 2-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE INFSNZ REG, 1, 0
ZERO
NZERO
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 711
Before Instruction
PC = Address (HERE)
After Instruction
REG = REG + 1
If REG ≠ 0;
PC = Address (NZERO)
If REG = 0;
PC = Address (ZERO)
IORLW Inclusive OR literal with W
Syntax: IORLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .OR. k → W
Status Affected: N, Z
Encoding: 0000 1001 kkkk kkkk
Description: The contents of W are ORed with the 8-bit literal ‘k’. The result is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write to W
Example: IORLW 35h
Before Instruction
W = 9Ah
After Instruction
W = BFh
IORWF Inclusive OR W with f
Syntax: IORWF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 712
...........continued
IORWF Inclusive OR W with f
Operation: (W) .OR. (f) → dest
Status
Affected:
N, Z
Encoding: 0001 00da ffff ffff
Description: Inclusive OR W with register ‘f’. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: IORWF RESULT, 0, 1
Before Instruction
RESULT = 13h
W = 91h
After Instruction
RESULT = 13h
W = 93h
LFSR Load FSR
Syntax: LFSR f, k
Operands: 0 ≤ f ≤ 2
0 ≤ k ≤ 4095
Operation: k → FSRf
Status Affected: None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 713
...........continued
LFSR Load FSR
Encoding: 1110
1111
1110
0000
00ff
k7kkk
k11kkk
kkkk
Description: The 12-bit literal ‘k’ is loaded into the File Select Register pointed to by ‘f’.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal ‘k’ MSB Process Data Write
literal ‘k’ MSB to FSRfH
Decode Read literal ‘k’ LSB Process Data Write literal ‘k’ to FSRfL
Example: LFSR 2, 3ABh
After Instruction
FSR2H = 03h
FSR2L = ABh
MOVF Move f
Syntax: MOVF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: f → dest
Status
Affected:
N, Z
Encoding: 0101 00da ffff ffff
Description: The contents of register ‘f’ are moved to a destination dependent upon the
status of ‘d’. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default). Location ‘f’ can be anywhere in the
256-byte bank.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 714
...........continued
MOVF Move f
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write W
Example: MOVF REG, 0, 0
Before Instruction
REG = 22h
W = FFh
After Instruction
REG = 22h
W = 22h
MOVFF Move f to f
Syntax: MOVFF fs,fd
Operands: 0 ≤ fs ≤ 4095
0 ≤ fd ≤ 4095
Operation: (fs) → fd
Status
Affected:
None
Encoding:
1st word
(source)
2nd word
(destin.)
1100
1111
ffff
ffff
ffff
ffff
ffffs
ffffd
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 715
...........continued
MOVFF Move f to f
Description: The contents of source register ‘fs’ are moved to destination register ‘fd’.
Location of source ‘fs’ can be anywhere in the 4096-byte data space (000h to FFFh)
and location of destination ‘fd’ can also be anywhere from 000h to FFFh.
Either source or destination can be W (a useful special situation).
MOVFF is particularly useful for
transferring a data memory location to a peripheral register (such as the transmit buffer
or an I/O port).
The MOVFF instruction cannot use the PCL, TOSU, TOSH or TOSL as the destination
register.
Words: 2
Cycles: 2 (3)
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’ (src)
Process Data No
operation
Decode No
operation
No dummy read
No
operation
Write
register ‘f’ (dest)
Example: MOVFF REG1, REG2
Before Instruction
REG1 = 33h
REG2 = 11h
After Instruction
REG1 = 33h
REG2 = 33h
MOVLB Move literal to low nibble in BSR
Syntax: MOVLW k
Operands: 0 ≤ k ≤ 255
Operation: k → BSR
Status Affected: None
Encoding: 0000 0001 kkkk kkkk
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 716
...........continued
MOVLB Move literal to low nibble in BSR
Description: The 8-bit literal ‘k’ is loaded into the Bank Select Register (BSR). The value of
BSR<7:4> always remains ‘0’, regardless of the value of k7:k4.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write literal ‘k’ to BSR
Example: MOVLB 5
Before Instruction
BSR Register = 02h
After Instruction
BSR Register = 05h
MOVLW Move literal to W
Syntax: MOVLW k
Operands: 0 ≤ k ≤ 255
Operation: k → W
Status Affected: None
Encoding: 0000 1110 kkkk kkkk
Description: The 8-bit literal ‘k’ is loaded into W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write to W
Example: MOVLW 5Ah
After Instruction
W = 5Ah
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 717
MOVWF Move W to f
Syntax: MOVWF f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: (W) → f
Status
Affected:
None
Encoding: 0110 111a ffff ffff
Description: Move data from W to register ‘f’.
Location ‘f’ can be anywhere in the
256-byte bank.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
Example: MOVWF REG, 0
Before Instruction
W = 4Fh
REG = FFh
After Instruction
W = 4Fh
REG = 4Fh
MULLW Multiply literal with W
Syntax: MULLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) x k → PRODH:PRODL
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 718
...........continued
MULLW Multiply literal with W
Status
Affected:
None
Encoding: 0000 1101 kkkk kkkk
Description: An unsigned multiplication is carried out between the contents of W and the 8-bit literal
‘k’. The 16-bit result is placed in the PRODH:PRODL register pair. PRODH contains the
high byte.
W is unchanged.
None of the Status flags are affected.
Note that neither overflow nor carry is possible in this operation. A zero result is
possible but not detected.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write
registers PRODH:
PRODL
Example: MULLW 0C4h
Before Instruction
W = E2h
PRODH = ?
PRODL = ?
After Instruction
W = E2h
PRODH = ADh
PRODL = 08h
MULWF Multiply W with f
Syntax: MULWF f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: (W) x (f) → PRODH:PRODL
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 719
...........continued
MULWF Multiply W with f
Status
Affected:
None
Encoding: 0000 001a ffff ffff
Description: An unsigned multiplication is carried out between the contents of W and the register file
location ‘f’. The 16-bit result is stored in the PRODH:PRODL register pair. PRODH
contains the high byte. Both W and ‘f’ are unchanged.
None of the Status flags are affected.
Note that neither overflow nor carry is possible in this operation. A zero result is possible
but not detected.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction
operates in Indexed Literal Offset Addressing mode whenever
f ≤ 95 (5Fh). See Section 35.2.3 “Byte-Oriented and Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
registers PRODH:
PRODL
Example: MULWF REG, 1
Before Instruction
W = C4h
REG = B5h
PRODH = ?
PRODL = ?
After Instruction
W = C4h
REG = B5h
PRODH = 8Ah
PRODL = 94h
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 720
NEGF Negate f
Syntax: NEGF f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: ( f ) + 1 → f
Status
Affected:
N, OV, C, DC, Z
Encoding: 0110 110a ffff ffff
Description: Location ‘f’ is negated using two’s
complement. The result is placed in the data memory location ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
Example: NEGF REG, 1
Before Instruction
REG = 0011 1010 [3Ah]
After Instruction
REG = 1100 0110 [C6h]
NOP No Operation
Syntax: NOP
Operands: None
Operation: No operation
Status Affected: None
Encoding: 0000
1111
0000
xxxx
0000
xxxx
0000
xxxx
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 721
...........continued
NOP No Operation
Description: No operation.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
Example:
None.
POP Pop Top of Return Stack
Syntax: POP
Operands: None
Operation: (TOS) → bit bucket
Status
Affected:
None
Encoding: 0000 0000 0000 0110
Description: The TOS value is pulled off the return stack and is discarded. The TOS value then
becomes the previous value that was pushed onto the return stack.
This instruction is provided to enable the user to properly manage the return stack to
incorporate a software stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
POP TOS value No
operation
Example: POP
GOTO
NEW
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 722
Before Instruction
TOS = 0031A2h
Stack (1 level down) = 014332h
After Instruction
TOS = 014332h
PC = NEW
PUSH Push Top of Return Stack
Syntax: PUSH
Operands: None
Operation: (PC + 2) → TOS
Status
Affected:
None
Encoding: 0000 0000 0000 0101
Description: The PC + 2 is pushed onto the top of the return stack. The previous TOS value is
pushed down on the stack.
This instruction allows implementing a software stack by modifying TOS and then
pushing it onto the return stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode PUSH PC + 2 onto return stack No
operation
No
operation
Example: PUSH
Before Instruction
TOS = 345Ah
PC = 0124h
After Instruction
PC = 0126h
TOS = 0126h
Stack (1 level down) = 345Ah
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 723
RCALL Relative Call
Syntax: RCALL n
Operands: -1024 ≤ n ≤ 1023
Operation: (PC) + 2 → TOS,
(PC) + 2 + 2n → PC
Status
Affected:
None
Encoding: 1101 1nnn nnnn nnnn
Description: Subroutine call with a jump up to 1K from the current location. First, return address (PC
+ 2) is pushed onto the stack. Then, add the 2’s complement number ‘2n’ to the PC.
Since the PC will have incremented to fetch the next instruction, the new address will be
PC + 2 + 2n. This instruction is a
2-cycle instruction.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal ‘n’
PUSH PC to stack
Process Data Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE RCALL Jump
Before Instruction
PC = Address (HERE)
After Instruction
PC = Address (Jump)
TOS = Address (HERE + 2)
RESET Reset
Syntax: RESET
Operands: None
Operation: Reset all registers and flags that are affected by a MCLR Reset.
Status Affected: All
Encoding: 0000 0000 1111 1111
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 724
...........continued
RESET Reset
Description: This instruction provides a way to
execute a MCLR Reset by software.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Start
Reset
No
operation
No
operation
Example: RESET
After Instruction
Registers = Reset Value
Flags* = Reset Value
RETFIE Return from Interrupt
Syntax: RETFIE {s}
Operands: s [0,1]
Operation: (TOS) → PC,
1 → GIE/GIEH or PEIE/GIEL,
if s = 1
(WS) → W,
(STATUSS) → Status,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged.
Status
Affected:
GIE/GIEH, PEIE/GIEL.
Encoding: 0000 0000 0001 000s
Description: Return from interrupt. Stack is popped and Top-of-Stack (TOS) is loaded into the PC.
Interrupts are enabled by
setting either the high or low priority
global interrupt enable bit. If ‘s’ = 1, the contents of the shadow registers, WS, STATUSS
and BSRS, are loaded into their corresponding registers, W,
Status and BSR. If ‘s’ = 0, no update of these registers occurs (default).
Words: 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 725
...........continued
RETFIE Return from Interrupt
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
POP PC from stack
Set GIEH or GIEL
No
operation
No
operation
No
operation
No
operation
Example: RETFIE 1
After Interrupt
PC = TOS
W = WS
BSR = BSRS
Status = STATUSS
GIE/GIEH, PEIE/GIEL = 1
RETLW Return literal to W
Syntax: RETLW k
Operands: 0 ≤ k ≤ 255
Operation: k → W,
(TOS) → PC,
PCLATU, PCLATH are unchanged
Status
Affected:
None
Encoding: 0000 1100 kkkk kkkk
Description: W is loaded with the 8-bit literal ‘k’. The Program Counter is loaded from the top of the
stack (the return address). The high address latch (PCLATH) remains unchanged.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data POP PC from stack, Write to W
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 726
No
operation
No
operation
No
operation
No
operation
Example:
CALL TABLE ; contains table
; offset value
; W now has
; table value
:
TABLE
ADDWF PCL ; W = offset
RETLW k0 ; Begin table
RETLW k1 ;
:
:
RETLW kn ; End of table
Before Instruction
W = 07h
After Instruction
W = value of kn
RETURN Return from Subroutine
Syntax: RETURN {s}
Operands: s [0,1]
Operation: (TOS) → PC,
if s = 1
(WS) → W,
(STATUSS) → Status,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged
Status
Affected:
None
Encoding: 0000 0000 0001 001s
Description: Return from subroutine. The stack is popped and the top of the stack (TOS) is loaded
into the Program Counter. If ‘s’= 1, the contents of the shadow
registers, WS, STATUSS and BSRS, are loaded into their corresponding
registers, W, Status and BSR. If
‘s’ = 0, no update of these registers occurs (default).
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 727
Decode No
operation
Process Data POP PC from stack
No
operation
No
operation
No
operation
No
operation
Example: RETURN
After Instruction:
PC = TOS
RLCF Rotate Left f through Carry
Syntax: RLCF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f<n>) → dest<n + 1>,
(f<7>) → C,
(C) → dest<0>
Status
Affected:
C, N, Z
Encoding: 0011 01da ffff ffff
Description: The contents of register ‘f’ are rotated one bit to the left through the CARRY flag. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is stored back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction
operates in Indexed Literal Offset Addressing mode whenever
f ≤ 95 (5Fh). See Section 35.2.3 “Byte-Oriented and Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Cregister f
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 728
Example: RLCF REG, 0, 0
Before Instruction
REG = 1110 0110
C = 0
After Instruction
REG = 1110 0110
W = 1100 1100
C = 1
RLNCF Rotate Left f (No Carry)
Syntax: RLNCF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f<n>) → dest<n + 1>,
(f<7>) → dest<0>
Status
Affected:
N, Z
Encoding: 0100 01da ffff ffff
Description: The contents of register ‘f’ are rotated one bit to the left. If ‘d’ is ‘0’, the result is placed in
W. If ‘d’ is ‘1’, the result is stored back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in Indexed
Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
register f
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: RLNCF REG, 1, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 729
Before Instruction
REG = 1010 1011
After Instruction
REG = 0101 0111
RRCF Rotate Right f through Carry
Syntax: RRCF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f<n>) → dest<n – 1>,
(f<0>) → C,
(C) → dest<7>
Status
Affected:
C, N, Z
Encoding: 0011 00da ffff ffff
Description: The contents of register ‘f’ are rotated one bit to the right through the CARRY flag. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Cregister f
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: RRCF REG, 0, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 730
Before Instruction
REG = 1110 0110
C = 0
After Instruction
REG = 1110 0110
W = 0111 0011
C = 0
RRNCF Rotate Right f (No Carry)
Syntax: RRNCF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f<n>) → dest<n – 1>,
(f<0>) → dest<7>
Status
Affected:
N, Z
Encoding: 0100 00da ffff ffff
Description: The contents of register ‘f’ are rotated one bit to the right. If ‘d’ is ‘0’, the result is placed
in W. If ‘d’ is ‘1’, the result is placed back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank will be selected (default), overriding the BSR value. If ‘a’ is
‘1’, then the bank will be selected as per the BSR value.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
register f
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example 1: RRNCF REG, 1, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 731
Before Instruction
REG = 1101 0111
After Instruction
REG = 1110 1011
Example 2: RRNCF REG, 0, 0
Before Instruction
W = ?
REG = 1101 0111
After Instruction
W = 1110 1011
REG = 1101 0111
SETF Set f
Syntax: SETF f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: FFh → f
Status
Affected:
None
Encoding: 0110 100a ffff ffff
Description: The contents of the specified register are set to FFh.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write
register ‘f’
Example: SETF REG, 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 732
Before Instruction
REG = 5Ah
After Instruction
REG = FFh
SLEEP Enter Sleep mode
Syntax: SLEEP
Operands: None
Operation: 00h → WDT,
0 → WDT postscaler,
1 → TO,
0 → PD
Status
Affected:
TO, PD
Encoding: 0000 0000 0000 0011
Description: The Power-down Status bit (PD) is cleared. The Time-out Status bit (TO) is set.
Watchdog Timer and its postscaler are cleared.
The processor is put into Sleep mode with the oscillator stopped.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process Data Go to
Sleep
Example: SLEEP
Before Instruction
TO = ?
PD = ?
After Instruction
TO = 1 †
PD = 0
† If WDT causes wake-up, this bit is cleared.
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 733
SUBFWB Subtract f from W with borrow (Continued)
Syntax: SUBFWB f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (W) – (f) – (C) → dest
Status
Affected:
N, OV, C, DC, Z
Encoding: 0101 01da ffff ffff
Description: Subtract register ‘f’ and CARRY flag (borrow) from W (2’s complement method). If ‘d’ is
‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction
operates in Indexed Literal Offset Addressing mode whenever
f ≤ 95 (5Fh). See Section 35.2.3 “Byte-Oriented and Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example 1: SUBFWB REG, 1, 0
Before Instruction
REG = 3
W = 2
C = 1
After Instruction
REG = FF
W = 2
C = 0
Z = 0
N = 1 ; result is negative
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 734
Example 2: SUBFWB REG, 0, 0
Before Instruction
REG = 2
W = 5
C = 1
After Instruction
REG = 2
W = 3
C = 1
Z = 0
N = 0 ; result is positive
Example 3: SUBFWB REG, 1, 0
Before Instruction
REG = 1
W = 2
C = 0
After Instruction
REG = 0
W = 2
C = 1
Z = 1 ; result is zero
N = 0
SUBLW Subtract W from literal
Syntax: SUBLW k
Operands: 0 ≤ k ≤ 255
Operation: k – (W) →
Status Affected: N, OV, C, DC, Z
Encoding: 0000 1000 kkkk kkkk
Description W is subtracted from the 8-bit
literal ‘k’. The result is placed in W.
Words: 1
Cycles: 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 735
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write to W
Example 1: SUBLW 02h
Before Instruction
W = 01h
C = ?
After Instruction
W = 01h
C = 1 ; result is positive
Z = 0
N = 0
Example 2: SUBLW 02h
Before Instruction
W = 02h
C = ?
After Instruction
W = 00h
C = 1 ; result is zero
Z = 1
N = 0
Example 3: SUBLW 02h
Before Instruction
W = 03h
C = ?
After Instruction
W = FFh ; (2’s complement)
C = 0 ; result is negative
Z = 0
N = 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 736
SUBWF Subtract W from f
Syntax: SUBWF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) – (W) → dest
Status
Affected:
N, OV, C, DC, Z
Encoding: 0101 11da ffff ffff
Description: Subtract W from register ‘f’ (2’s
complement method). If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored
back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction
operates in Indexed Literal Offset Addressing mode whenever
f ≤ 95 (5Fh). See Section 35.2.3 “Byte-Oriented and Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example 1: SUBWF REG, 1, 0
Before Instruction
REG = 3
W = 2
C = ?
After Instruction
REG = 1
W = 2
C = 1 ; result is positive
Z = 0
N = 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 737
Example 2: SUBWF REG, 0, 0
Before Instruction
REG = 2
W = 2
C = ?
After Instruction
REG = 2
W = 0
C = 1 ; result is zero
Z = 1
N = 0
Example 3: SUBWF REG, 1, 0
Before Instruction
REG = 1
W = 2
C = ?
After Instruction
REG = FFh ;(2’s complement)
W = 2
C = 0 ; result is negative
Z = 0
N = 1
SUBWFB Subtract W from f with Borrow
Syntax: SUBWFB f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f) – (W) – (C) → dest
Status
Affected:
N, OV, C, DC, Z
Encoding: 0101 10da ffff ffff
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 738
...........continued
SUBWFB Subtract W from f with Borrow
Description: Subtract W and the CARRY flag (borrow) from register ‘f’ (2’s complement method). If ‘d’
is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example 1: SUBWFB REG, 1, 0
Before Instruction
REG = 19h (0001 1001)
W = 0Dh (0000 1101)
C = 1
After Instruction
REG = 0Ch (0000 1100)
W = 0Dh (0000 1101)
C = 1
Z = 0
N = 0 ; result is positive
Example 2: SUBWFB REG, 0, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 739
Before Instruction
REG = 1Bh (0001 1011)
W = 1Ah (0001 1010)
C = 0
After Instruction
REG = 1Bh (0001 1011)
W = 00h
C = 1
Z = 1 ; result is zero
N = 0
Example 3: SUBWFB REG, 1, 0
Before Instruction
REG = 03h (0000 0011)
W = 0Eh (0000 1110)
C = 1
After Instruction
REG = F5h (1111 0101)
; [2’s comp]
W = 0Eh (0000 1110)
C = 0
Z = 0
N = 1 ; result is negative
SWAPF Swap f
Syntax: SWAPF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (f<3:0>) → dest<7:4>,
(f<7:4>) → dest<3:0>
Status
Affected:
None
Encoding: 0011 10da ffff ffff
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 740
...........continued
SWAPF Swap f
Description: The upper and lower nibbles of register ‘f’ are exchanged. If ‘d’ is ‘0’, the result is placed
in W. If ‘d’ is ‘1’, the result is placed in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: SWAPF REG, 1, 0
Before Instruction
REG = 53h
After Instruction
REG = 35h
TBLRD Table Read
Syntax: TBLRD ( *; *+; *-; +*)
Operands: None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 741
...........continued
TBLRD Table Read
Operation: if TBLRD *,
(Prog Mem (TBLPTR)) → TABLAT;
TBLPTR – No Change;
if TBLRD *+,
(Prog Mem (TBLPTR)) → TABLAT;
(TBLPTR) + 1 → TBLPTR;
if TBLRD *-,
(Prog Mem (TBLPTR)) → TABLAT;
(TBLPTR) – 1 → TBLPTR;
if TBLRD +*,
(TBLPTR) + 1 → TBLPTR;
(Prog Mem (TBLPTR)) → TABLAT;
Status
Affected:
None
Encoding:
0000 0000 0000
10nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description: This instruction is used to read the contents of Program Memory (P.M.). To address the
program memory, a pointer called Table Pointer (TBLPTR) is used.
The TBLPTR (a 21-bit pointer) points to each byte in the program memory. TBLPTR has
a 2-Mbyte address range.
TBLPTR[0] = 0: Least Significant Byte of Program Memory Word
TBLPTR[0] = 1: Most Significant Byte of Program Memory Word
The TBLRD instruction can modify the value of TBLPTR as follows:
no change
post-increment
post-decrement
pre-increment
Words: 1
Cycles: 2
Q Cycle Activity:
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 742
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
No
operation
No operation
(Read Program Memory)
No
operation
No operation
(Write TABLAT)
TBLRD Table Read (Continued)
Example1: TBLRD *+ ;
Before Instruction
TABLAT = 55h
TBLPTR = 00A356h
MEMORY (00A356h) = 34h
After Instruction
TABLAT = 34h
TBLPTR = 00A357h
Example2: TBLRD +* ;
Before Instruction
TABLAT = AAh
TBLPTR = 01A357h
MEMORY (01A357h) = 12h
MEMORY (01A358h) = 34h
After Instruction
TABLAT = 34h
TBLPTR = 01A358h
TBLWT
(Continued) Table Write
Syntax: TBLWT ( *; *+; *-; +*)
Operands: None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 743
...........continued
TBLWT
(Continued) Table Write
Operation: if TBLWT*,
(TABLAT) → Holding Register;
TBLPTR – No Change;
if TBLWT*+,
(TABLAT) → Holding Register;
(TBLPTR) + 1 → TBLPTR;
if TBLWT*-,
(TABLAT) → Holding Register;
(TBLPTR) – 1 → TBLPTR;
if TBLWT+*,
(TBLPTR) + 1 → TBLPTR;
(TABLAT) → Holding Register;
Status
Affected:
None
Encoding:
0000 0000 0000
11nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description: This instruction uses the LSBs of TBLPTR to determine which of the holding registers
the TABLAT is written to. The holding registers are used to program the contents of
Program Memory (P.M.). (Refer to the “Program Flash Memory” section for additional
details on programming Flash memory.)
The TBLPTR (a 21-bit pointer) points to each byte in the program memory. TBLPTR has
a 2-MByte address range. The LSb of the TBLPTR selects which byte of the program
memory location to access.
TBLPTR[0] = 0: Least Significant Byte of Program Memory Word
TBLPTR[0] = 1: Most Significant Byte of Program Memory Word
The TBLWT instruction can modify the value of TBLPTR as follows:
no change
post-increment
post-decrement
pre-increment
Words: 1
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 744
...........continued
TBLWT
(Continued) Table Write
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
No
operation
No
operation
(Read
TABLAT)
No
operation
No
operation
(Write to Holding
Register )
TBLWT Table Write (Continued)
Example1: TBLWT *+;
Before Instruction
TABLAT = 55h
TBLPTR = 00A356h
HOLDING REGISTER
(00A356h) = FFh
After Instructions (table write completion)
TABLAT = 55h
TBLPTR = 00A357h
HOLDING REGISTER
(00A356h) = 55h
Example 2: TBLWT +*;
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 745
Before Instruction
TABLAT = 34h
TBLPTR = 01389Ah
HOLDING REGISTER
(01389Ah) = FFh
HOLDING REGISTER
(01389Bh) = FFh
After Instruction (table write completion)
TABLAT = 34h
TBLPTR = 01389Bh
HOLDING REGISTER
(01389Ah) = FFh
HOLDING REGISTER
(01389Bh) = 34h
TSTFSZ Test f, skip if 0
Syntax: TSTFSZ f {,a}
Operands: 0 ≤ f ≤ 255
a [0,1]
Operation: skip if f = 0
Status
Affected:
None
Encoding: 0110 011a ffff ffff
Description: If ‘f’ = 0, the next instruction fetched during the current instruction execution is discarded
and a NOP is executed, making this a 2-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1(2)
Note: Three cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 746
Decode Read
register ‘f’
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE TSTFSZ CNT, 1
NZERO :
ZERO :
Before Instruction
PC = Address (HERE)
After Instruction
If CNT = 00h,
PC = Address (ZERO)
If CNT ≠ 00h,
PC = Address (NZERO)
XORLW Exclusive OR literal with W
Syntax: XORLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .XOR. k →
Status Affected: N, Z
Encoding: 0000 1010 kkkk kkkk
Description: The contents of W are XORed with the 8-bit literal ‘k’. The result is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 747
Decode Read
literal ‘k’
Process Data Write to W
Example: XORLW 0AFh
Before Instruction
W = B5h
After Instruction
W = 1Ah
XORWF Exclusive OR W with f
Syntax: XORWF f {,d {,a}}
Operands: 0 ≤ f ≤ 255
d [0,1]
a [0,1]
Operation: (W) .XOR. (f) → dest
Status
Affected:
N, Z
Encoding: 0001 10da ffff ffff
Description: Exclusive OR the contents of W with register ‘f’. If ‘d’ is ‘0’, the result is stored in W. If ‘d’
is ‘1’, the result is stored back in the register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected. If ‘a’ is ‘1’, the BSR is used to select the GPR
bank.
If ‘a’ is ‘0’ and the extended instruction set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode whenever f ≤ 95 (5Fh). See 37.2.3 Byte-
Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: XORWF REG, 1, 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 748
Before Instruction
REG = AFh
W = B5h
After Instruction
REG = 1Ah
W = B5h
37.2 Extended Instruction Set
In addition to the standard 75 instructions of the PIC18 instruction set, PIC18F26/45/46Q10 devices also
provide an optional extension to the core CPU functionality. The added features include eight additional
instructions that augment Indirect and Indexed Addressing operations and the implementation of Indexed
Literal Offset Addressing mode for many of the standard PIC18 instructions.
The additional features of the extended instruction set are disabled by default. To enable them, users
must set the XINST Configuration bit.
The instructions in the extended set can all be classified as literal operations, which either manipulate the
File Select Registers, or use them for Indexed Addressing. Two of the instructions, ADDFSR and
SUBFSR, each have an additional special instantiation for using FSR2. These versions (ADDULNK and
SUBULNK) allow for automatic return after execution.
The extended instructions are specifically implemented to optimize re-entrant program code (that is, code
that is recursive or that uses a software stack) written in high-level languages, particularly C. Among
other things, they allow users working in high-level languages to perform certain operations on data
structures more efficiently. These include:
dynamic allocation and deallocation of software stack space when entering and leaving subroutines
function pointer invocation
software Stack Pointer manipulation
manipulation of variables located in a software stack
A summary of the instructions in the extended instruction set is provided in 37.2.1 Extended Instruction
Syntax. Detailed descriptions are provided in 37.2.2 Extended Instruction Set. The opcode field
descriptions in 37.1 Standard Instruction Set apply to both the standard and extended PIC18 instruction
sets.
Important:  The instruction set extension and the Indexed Literal Offset Addressing mode were
designed for optimizing applications written in C; the user may likely never use these
instructions directly in assembler. The syntax for these commands is provided as a reference for
users who may be reviewing code that has been generated by a compiler.
37.2.1 Extended Instruction Syntax
Most of the extended instructions use indexed arguments, using one of the File Select Registers and
some offset to specify a source or destination register. When an argument for an instruction serves as
part of Indexed Addressing, it is enclosed in square brackets (“[ ]”). This is done to indicate that the
PIC18F26/45/46Q10
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 749
argument is used as an index or offset. MPASM Assembler will flag an error if it determines that an
index or offset value is not bracketed.
When the extended instruction set is enabled, brackets are also used to indicate index arguments in byte-
oriented and bit-oriented instructions. This is in addition to other changes in their syntax. For more details,
see 37.2.3.1 Extended Instruction Syntax with Standard PIC18 Commands.
Important:  In the past, square brackets have been used to denote optional arguments in the
PIC18 and earlier instruction sets. In this text and going forward, optional arguments are
denoted by braces (“{ }”).
Table 37-3. Extensions to the PIC18 Instruction Set
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected
MSb LSb
ADDFSR f, k Add literal to FSR 1 1110 1000 ffkk kkkk None
ADDULNK k Add literal to FSR2 and return 2 1110 1000 11kk kkkk None
CALLW Call subroutine using WREG 2 0000 0000 0001 0100 None
MOVSF zs, fdMove zs (source) to 1st word 2 1110 1011 0zzz zzzz None
fd (destination) 2nd word 1111 ffff ffff ffff
MOVSS zs, zdMove zs (source) to 1st word 2 1110 1011 1zzz zzzz None
zd (destination) 2nd word 1111 xxxx xzzz zzzz
PUSHL k Store literal at FSR2,
decrement FSR2
11110 1010 kkkk kkkk None
SUBFSR f, k Subtract literal from FSR 1 1110 1001 ffkk kkkk None
SUBULNK k Subtract literal from FSR2 and
return
21110 1001 11kk kkkk None
37.2.2 Extended Instruction Set
ADDFSR Add Literal to FSR
Syntax: ADDFSR f, k
Operands: 0 ≤ k ≤ 63
f [ 0, 1, 2 ]
Operation: FSR(f) + k → FSR(f)
Status Affected: None
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...........continued
ADDFSR Add Literal to FSR
Encoding: 1110 1000 ffkk kkkk
Description: The 6-bit literal ‘k’ is added to the contents of the FSR specified by ‘f’.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process Data Write to
FSR
Example: ADDFSR 2, 23h
Before Instruction
FSR2 = 03FFh
After Instruction
FSR2 = 0422h
ADDULNK Add Literal to FSR2 and Return
Syntax: ADDULNK k
Operands: 0 ≤ k ≤ 63
Operation: FSR2 + k → FSR2,
(TOS) → PC
Status
Affected:
None
Encoding: 1110 1000 11kk kkkk
Description: The 6-bit literal ‘k’ is added to the contents of FSR2. A RETURN is then executed by
loading the PC with the TOS.
The instruction takes two cycles to execute; a NOP is performed during the second
cycle.
This may be thought of as a special case of the ADDFSR instruction, where f = 3 (binary
‘11’); it operates only on FSR2.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
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Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 751
Decode Read
literal ‘k’
Process Data Write to
FSR
No
Operation
No
Operation
No
Operation
No
Operation
Example: ADDULNK 23h
Before Instruction
FSR2 = 03FFh
PC = 0100h
After Instruction
FSR2 = 0422h
PC = (TOS)
Important:  All PIC18 instructions may take an optional label argument preceding the
instruction mnemonic for use in symbolic addressing. If a label is used, the instruction syntax
then becomes: {label} instruction argument(s).
CALLW Subroutine Call Using WREG
Syntax: CALLW
Operands: None
Operation: (PC + 2) → TOS,
(W) → PCL,
(PCLATH) → PCH,
(PCLATU) → PCU
Status
Affected:
None
Encoding: 0000 0000 0001 0100
Description First, the return address (PC + 2) is pushed onto the return stack. Next, the contents of
W are written to PCL; the existing value is discarded. Then, the contents of PCLATH and
PCLATU are latched into PCH and PCU,
respectively. The second cycle is
executed as a NOP instruction while the new next instruction is fetched.
Unlike CALL, there is no option to update W, Status or BSR.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 752
Decode Read
WREG
PUSH PC to stack No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CALLW
Before Instruction
PC = address (HERE)
PCLATH = 10h
PCLATU = 00h
W = 06h
After Instruction
PC = 001006h
TOS = address (HERE + 2)
PCLATH = 10h
PCLATU = 00h
W = 06h
MOVSF Move Indexed to f
Syntax: MOVSF [zs], fd
Operands: 0 ≤ zs ≤ 127
0 ≤ fd ≤ 4095
Operation: ((FSR2) + zs) → fd
Status
Affected:
None
Encoding:
1st word
(source)
2nd word
(destin.)
1110
1111
1011
ffff
0zzz
ffff
zzzzs
ffffd
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Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 753
...........continued
MOVSF Move Indexed to f
Description: The contents of the source register are moved to destination register ‘fd’. The actual
address of the source register is determined by adding the 7-bit literal offset ‘zs’ in the
first word to the value of FSR2. The address of the destination register is specified by
the 12-bit literal ‘fd’ in the second word. Both addresses can be anywhere in the 4096-
byte data space (000h to FFFh).
The MOVSF instruction cannot use the PCL, TOSU, TOSH or TOSL as the destination
register.
If the resultant source address points to an Indirect Addressing register, the value
returned will be 00h.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Determine source addr Determine
source addr
Read
source reg
Decode No
operation
No dummy read
No
operation
Write
register ‘f’ (dest)
Example: MOVSF [05h], REG2
Before Instruction
FSR2 = 80h
Contents
of 85h = 33h
REG2 = 11h
After Instruction
FSR2 = 80h
Contents
of 85h = 33h
REG2 = 33h
MOVSS Move Indexed to Indexed
Syntax: MOVSS [zs], [zd]
Operands: 0 ≤ zs ≤ 127
0 ≤ zd ≤ 127
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...........continued
MOVSS Move Indexed to Indexed
Operation: ((FSR2) + zs) → ((FSR2) + zd)
Status
Affected:
None
Encoding:
1st word
(source)
2nd word
(dest.)
1110
1111
1011
xxxx
1zzz
xzzz
zzzzs
zzzzd
Description The contents of the source register are moved to the destination register. The addresses
of the source and destination registers are determined by adding the 7-bit literal offsets
‘zs’ or ‘zd’,
respectively, to the value of FSR2. Both registers can be located anywhere in the 4096-
byte data memory space (000h to FFFh).
The MOVSS instruction cannot use the PCL, TOSU, TOSH or TOSL as the destination
register.
If the resultant source address points to an Indirect Addressing register, the value
returned will be 00h. If the
resultant destination address points to an Indirect Addressing register, the instruction will
execute as a NOP.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Determine source addr Determine
source addr
Read
source reg
Decode Determine
dest addr
Determine
dest addr
Write
to dest reg
Example: MOVSS [05h], [06h]
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Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 755
Before Instruction
FSR2 = 80h
Contents
of 85h = 33h
Contents
of 86h = 11h
After Instruction
FSR2 = 80h
Contents
of 85h = 33h
Contents
of 86h = 33h
PUSHL Store Literal at FSR2, Decrement FSR2
Syntax: PUSHL k
Operands: 0 ≤ k ≤ 255
Operation: k → (FSR2),
FSR2 – 1 → FSR2
Status
Affected:
None
Encoding: 1111 1010 kkkk kkkk
Description: The 8-bit literal ‘k’ is written to the data memory address specified by FSR2. FSR2 is
decremented by 1 after the operation.
This instruction allows users to push values onto a software stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read ‘k’ Process
data
Write to
destination
Example: PUSHL 08h
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Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 756
Before Instruction
FSR2H:FSR2L = 01ECh
Memory (01ECh) = 00h
After Instruction
FSR2H:FSR2L = 01EBh
Memory (01ECh) = 08h
SUBFSR Subtract Literal from FSR
Syntax: SUBFSR f, k
Operands: 0 ≤ k ≤ 63
f [ 0, 1, 2 ]
Operation: FSR(f) – k → FSRf
Status Affected: None
Encoding: 1110 1001 ffkk kkkk
Description: The 6-bit literal ‘k’ is subtracted from the contents of the FSR specified by ‘f’.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: SUBFSR 2, 23h
Before Instruction
FSR2 = 03FFh
After Instruction
FSR2 = 03DCh
SUBULNK Subtract Literal from FSR2 and Return
Syntax: SUBULNK k
Operands: 0 ≤ k ≤ 63
Operation: FSR2 – k → FSR2
(TOS) → PC
Status
Affected:
None
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 757
...........continued
SUBULNK Subtract Literal from FSR2 and Return
Encoding: 1110 1001 11kk kkkk
Description: The 6-bit literal ‘k’ is subtracted from the contents of the FSR2. A RETURN is then
executed by loading the PC with the TOS.
The instruction takes two cycles to
execute; a NOP is performed during the second cycle.
This may be thought of as a special case of the SUBFSR instruction, where f = 3 (binary
‘11’); it operates only on FSR2.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
No
Operation
No
Operation
No
Operation
No
Operation
Example: SUBULNK 23h
Before Instruction
FSR2 = 03FFh
PC = 0100h
After Instruction
FSR2 = 03DCh
PC = (TOS)
37.2.3 Byte-Oriented and
Bit-Oriented Instructions in Indexed Literal Offset Mode
Important:  Enabling the PIC18 instruction set extension may cause legacy applications to
behave erratically or fail entirely.
In addition to eight new commands in the extended set, enabling the extended instruction set also
enables Indexed Literal Offset Addressing mode (Section “Indexed Addressing with Literal Offset”). This
has a significant impact on the way that many commands of the standard PIC18 instruction set are
interpreted.
When the extended set is disabled, addresses embedded in opcodes are treated as literal memory
locations: either as a location in the Access Bank (‘a’ = 0), or in a GPR bank designated by the BSR (‘a’ =
1). When the extended instruction set is enabled and ‘a’ = 0, however, a file register argument of 5Fh or
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 758
less is interpreted as an offset from the pointer value in FSR2 and not as a literal address. For practical
purposes, this means that all instructions that use the Access RAM bit as an argument – that is, all byte-
oriented and bit-oriented instructions, or almost half of the core PIC18 instructions – may behave
differently when the extended instruction set is enabled.
When the content of FSR2 is 00h, the boundaries of the Access RAM are essentially remapped to their
original values. This may be useful in creating backward compatible code. If this technique is used, it may
be necessary to save the value of FSR2 and restore it when moving back and forth between C and
assembly routines in order to preserve the Stack Pointer. Users must also keep in mind the syntax
requirements of the extended instruction set (see 37.2.3.1 Extended Instruction Syntax with Standard
PIC18 Commands).
Although the Indexed Literal Offset Addressing mode can be very useful for dynamic stack and pointer
manipulation, it can also be very annoying if a simple arithmetic operation is carried out on the wrong
register. Users who are accustomed to the PIC18 programming must keep in mind that, when the
extended instruction set is enabled, register addresses of 5Fh or less are used for Indexed Literal Offset
Addressing.
Representative examples of typical byte-oriented and bit-oriented instructions in the Indexed Literal Offset
Addressing mode are provided on the following page to show how execution is affected. The operand
conditions shown in the examples are applicable to all instructions of these types.
Related Links
10.5 Data Memory and the Extended Instruction Set
37.2.3.1 Extended Instruction Syntax with Standard PIC18 Commands
When the extended instruction set is enabled, the file register argument, ‘f’, in the standard byte-oriented
and bit-oriented commands is replaced with the literal offset value, ‘k’. As already noted, this occurs only
when ‘f’ is less than or equal to 5Fh. When an offset value is used, it must be indicated by square
brackets (“[ ]”). As with the extended instructions, the use of brackets indicates to the compiler that the
value is to be interpreted as an index or an offset. Omitting the brackets, or using a value greater than
5Fh within brackets, will generate an error in the MPASM assembler.
If the index argument is properly bracketed for Indexed Literal Offset Addressing, the Access RAM
argument is never specified; it will automatically be assumed to be ‘0’. This is in contrast to standard
operation (extended instruction set disabled) when ‘a’ is set on the basis of the target address. Declaring
the Access RAM bit in this mode will also generate an error in the MPASM assembler.
The destination argument, ‘d’, functions as before.
In the latest versions of the MPASM assembler, language support for the extended instruction set must
be explicitly invoked. This is done with either the command-line option, /y, or the PE directive in the
source listing.
Related Links
10.5 Data Memory and the Extended Instruction Set
37.2.4 Considerations when Enabling the Extended Instruction Set
It is important to note that the extensions to the instruction set may not be beneficial to all users. In
particular, users who are not writing code that uses a software stack may not benefit from using the
extensions to the instruction set.
Additionally, the Indexed Literal Offset Addressing mode may create issues with legacy applications
written to the PIC18 assembler. This is because instructions in the legacy code may attempt to address
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Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 759
registers in the Access Bank below 5Fh. Since these addresses are interpreted as literal offsets to FSR2
when the instruction set extension is enabled, the application may read or write to the wrong data
addresses.
When porting an application to the PIC18F26/45/46Q10 it is very important to consider the type of code.
A large, re-entrant application that is written in ‘C’ and would benefit from efficient compilation will do well
when using the instruction set extensions. Legacy applications that heavily use the Access Bank will most
likely not benefit from using the extended instruction set.
ADDWF ADD W to Indexed
(Indexed Literal Offset mode)
Syntax: ADDWF [k] {,d}
Operands: 0 ≤ k ≤ 95
d [0,1]
Operation: (W) + ((FSR2) + k) → dest
Status
Affected:
N, OV, C, DC, Z
Encoding: 0010 01d0 kkkk kkkk
Description: The contents of W are added to the contents of the register indicated by FSR2, offset by
the value ‘k’.
If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored back in
register ‘f’ (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read ‘k’ Process Data Write to
destination
Example: ADDWF [OFST] , 0
PIC18F26/45/46Q10
Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 760
Before Instruction
W = 17h
OFST = 2Ch
FSR2 = 0A00h
Contents
of 0A2Ch = 20h
After Instruction
W = 37h
Contents
of 0A2Ch = 20h
BSF Bit Set Indexed
(Indexed Literal Offset mode)
Syntax: BSF [k], b
Operands: 0 ≤ f ≤ 95
0 ≤ b ≤ 7
Operation: 1 → ((FSR2) + k)<b>
Status Affected: None
Encoding: 1000 bbb0 kkkk kkkk
Description: Bit ‘b’ of the register indicated by FSR2, offset by the value ‘k’, is set.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process Data Write to
destination
Example: BSF [FLAG_OFST], 7
Before Instruction
FLAG_OFST = 0Ah
FSR2 = 0A00h
Contents
of 0A0Ah = 55h
After Instruction
Contents
of 0A0Ah = D5h
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Instruction Set Summary
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 761
SETF Set Indexed
(Indexed Literal Offset mode)
Syntax: SETF [k]
Operands: 0 ≤ k ≤ 95
Operation: FFh → ((FSR2) + k)
Status Affected: None
Encoding: 0110 1000 kkkk kkkk
Description: The contents of the register indicated by FSR2, offset by ‘k’, are set to FFh.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read ‘k’ Process Data Write
register
Example: SETF [OFST]
Before Instruction
OFST = 2Ch
FSR2 = 0A00h
Contents
of 0A2Ch = 00h
After Instruction
Contents
of 0A2Ch = FFh
37.2.5 Special Considerations with Microchip MPLAB® IDE Tools
The latest versions of Microchip’s software tools have been designed to fully support the extended
instruction set of the PIC18F26/45/46Q10 family of devices. This includes the MPLAB C18 C compiler,
MPASM assembly language and MPLAB Integrated Development Environment (IDE).
When selecting a target device for software development, MPLAB IDE will automatically set default
Configuration bits for that device. The default setting for the XINST Configuration bit is ‘0’, disabling the
extended instruction set and Indexed Literal Offset Addressing mode. For proper execution of
applications developed to take advantage of the extended instruction set, XINST must be set during
programming.
To develop software for the extended instruction set, the user must enable support for the instructions
and the Indexed Addressing mode in their language tool(s). Depending on the environment being used,
this may be done in several ways:
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A menu option, or dialog box within the environment, that allows the user to configure the language
tool and its settings for the project
A command-line option
A directive in the source code
These options vary between different compilers, assemblers and development environments. Users are
encouraged to review the documentation accompanying their development systems for the appropriate
information.
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© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 763
38. Development Support
The PIC® microcontrollers (MCU) and dsPIC® digital signal controllers (DSC) are supported with a full
range of software and hardware development tools:
Integrated Development Environment
MPLAB® X IDE Software
Compilers/Assemblers/Linkers
MPLAB XC Compiler
MPASM Assembler
MPLINK Object Linker/
MPLIB Object Librarian
MPLAB Assembler/Linker/Librarian for
Various Device Families
Simulators
MPLAB X SIM Software Simulator
Emulators
MPLAB REAL ICE In-Circuit Emulator
In-Circuit Debuggers/Programmers
MPLAB ICD 3
PICkit 3 In-Circuit Debugger
Device Programmers
MPLAB PM3 Device Programmer
Low-Cost Demonstration/Development Boards, Evaluation Kits and Starter Kits
Third-party development tools
38.1 MPLAB X Integrated Development Environment Software
The MPLAB X IDE is a single, unified graphical user interface for Microchip and third-party software, and
hardware development tool that runs on Windows®, Linux and Mac OS® X. Based on the NetBeans IDE,
MPLAB X IDE is an entirely new IDE with a host of free software components and plug-ins for high-
performance application development and debugging. Moving between tools and upgrading from
software simulators to hardware debugging and programming tools is simple with the seamless user
interface.
With complete project management, visual call graphs, a configurable watch window and a feature-rich
editor that includes code completion and context menus, MPLAB X IDE is flexible and friendly enough for
new users. With the ability to support multiple tools on multiple projects with simultaneous debugging,
MPLAB X IDE is also suitable for the needs of experienced users.
Feature-Rich Editor:
Color syntax highlighting
Smart code completion makes suggestions and provides hints as you type
Automatic code formatting based on user-defined rules
Live parsing
User-Friendly, Customizable Interface:
PIC18F26/45/46Q10
Development Support
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 764
Fully customizable interface: toolbars, toolbar buttons, windows, window placement, etc.
Call graph window
Project-Based Workspaces:
Multiple projects
Multiple tools
Multiple configurations
Simultaneous debugging sessions
File History and Bug Tracking:
Local file history feature
Built-in support for Bugzilla issue tracker
38.2 MPLAB XC Compilers
The MPLAB XC Compilers are complete ANSI C compilers for all of Microchip’s 8, 16, and 32-bit MCU
and DSC devices. These compilers provide powerful integration capabilities, superior code optimization
and ease of use. MPLAB XC Compilers run on Windows, Linux or MAC OS X.
For easy source level debugging, the compilers provide debug information that is optimized to the
MPLAB X IDE.
The free MPLAB XC Compiler editions support all devices and commands, with no time or memory
restrictions, and offer sufficient code optimization for most applications.
MPLAB XC Compilers include an assembler, linker and utilities. The assembler generates relocatable
object files that can then be archived or linked with other relocatable object files and archives to create an
executable file. MPLAB XC Compiler uses the assembler to produce its object file. Notable features of the
assembler include:
Support for the entire device instruction set
Support for fixed-point and floating-point data
Command-line interface
Rich directive set
Flexible macro language
MPLAB X IDE compatibility
38.3 MPASM Assembler
The MPASM Assembler is a full-featured, universal macro assembler for PIC10/12/16/18 MCUs.
The MPASM Assembler generates relocatable object files for the MPLINK Object Linker, Intel® standard
HEX files, MAP files to detail memory usage and symbol reference, absolute LST files that contain source
lines and generated machine code, and COFF files for debugging.
The MPASM Assembler features include:
Integration into MPLAB X IDE projects
User-defined macros to streamline
assembly code
PIC18F26/45/46Q10
Development Support
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 765
Conditional assembly for multipurpose
source files
Directives that allow complete control over the assembly process
38.4 MPLINK Object Linker/MPLIB Object Librarian
The MPLINK Object Linker combines relocatable objects created by the MPASM Assembler. It can link
relocatable objects from precompiled libraries, using directives from a linker script.
The MPLIB Object Librarian manages the creation and modification of library files of precompiled code.
When a routine from a library is called from a source file, only the modules that contain that routine will be
linked in with the application. This allows large libraries to be used efficiently in many different
applications.
The object linker/library features include:
Efficient linking of single libraries instead of many smaller files
Enhanced code maintainability by grouping related modules together
Flexible creation of libraries with easy module listing, replacement, deletion and extraction
38.5 MPLAB Assembler, Linker and Librarian for Various Device Families
MPLAB Assembler produces relocatable machine code from symbolic assembly language for PIC24,
PIC32 and dsPIC DSC devices. MPLAB XC Compiler uses the assembler to produce its object file. The
assembler generates relocatable object files that can then be archived or linked with other relocatable
object files and archives to create an executable file. Notable features of the assembler include:
Support for the entire device instruction set
Support for fixed-point and floating-point data
Command-line interface
Rich directive set
Flexible macro language
MPLAB X IDE compatibility
38.6 MPLAB X SIM Software Simulator
The MPLAB X SIM Software Simulator allows code development in a PC-hosted environment by
simulating the PIC MCUs and dsPIC DSCs on an instruction level. On any given instruction, the data
areas can be examined or modified and stimuli can be applied from a comprehensive stimulus controller.
Registers can be logged to files for further run-time analysis. The trace buffer and logic analyzer display
extend the power of the simulator to record and track program execution, actions on I/O, most peripherals
and internal registers.
The MPLAB X SIM Software Simulator fully supports symbolic debugging using the MPLAB XC
Compilers, and the MPASM and MPLAB Assemblers. The software simulator offers the flexibility to
develop and debug code outside of the hardware laboratory environment, making it an excellent,
economical software development tool.
PIC18F26/45/46Q10
Development Support
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 766
38.7 MPLAB REAL ICE In-Circuit Emulator System
The MPLAB REAL ICE In-Circuit Emulator System is Microchip’s next generation high-speed emulator for
Microchip Flash DSC and MCU devices. It debugs and programs all 8, 16 and 32-bit MCU, and DSC
devices with the easy-to-use, powerful graphical user interface of the MPLAB X IDE.
The emulator is connected to the design engineer’s PC using a high-speed USB 2.0 interface and is
connected to the target with either a connector compatible with in-circuit debugger systems (RJ-11) or
with the new high-speed, noise tolerant, Low-Voltage Differential Signal (LVDS) interconnection (CAT5).
The emulator is field upgradable through future firmware downloads in MPLAB X IDE. MPLAB REAL ICE
offers significant advantages over competitive emulators including full-speed emulation, run-time variable
watches, trace analysis, complex breakpoints, logic probes, a ruggedized probe interface and long (up to
three meters) interconnection cables.
38.8 MPLAB ICD 3 In-Circuit Debugger System
The MPLAB ICD 3 In-Circuit Debugger System is Microchip’s most cost-effective, high-speed hardware
debugger/programmer for Microchip Flash DSC and MCU devices. It debugs and programs PIC Flash
microcontrollers and dsPIC DSCs with the powerful, yet easy-to-use graphical user interface of the
MPLAB IDE.
The MPLAB ICD 3 In-Circuit Debugger probe is connected to the design engineer’s PC using a high-
speed USB 2.0 interface and is connected to the target with a connector compatible with the MPLAB ICD
2 or MPLAB REAL ICE systems (RJ-11). MPLAB ICD 3 supports all MPLAB ICD 2 headers.
38.9 PICkit 3 In-Circuit Debugger/Programmer
The MPLAB PICkit 3 allows debugging and programming of PIC and dsPIC Flash microcontrollers at a
most affordable price point using the powerful graphical user interface of the MPLAB IDE. The MPLAB
PICkit 3 is connected to the design engineer’s PC using a full-speed USB interface and can be connected
to the target via a Microchip debug (RJ-11) connector (compatible with MPLAB ICD 3 and MPLAB REAL
ICE). The connector uses two device I/O pins and the Reset line to implement in-circuit debugging and
In-Circuit Serial Programming (ICSP).
38.10 MPLAB PM3 Device Programmer
The MPLAB PM3 Device Programmer is a universal, CE compliant device programmer with
programmable voltage verification at Vddmin and Vddmax for maximum reliability. It features a large LCD
display (128 x 64) for menus and error messages, and a modular, detachable socket assembly to support
various package types. The ICSP cable assembly is included as a standard item. In Stand-Alone mode,
the MPLAB PM3 Device Programmer can read, verify and program PIC devices without a PC connection.
It can also set code protection in this mode. The MPLAB PM3 connects to the host PC via an RS-232 or
USB cable. The MPLAB PM3 has high-speed communications and optimized algorithms for quick
programming of large memory devices, and incorporates an MMC card for file storage and data
applications.
38.11 Demonstration/Development Boards, Evaluation Kits, and Starter Kits
A wide variety of demonstration, development and evaluation boards for various PIC MCUs and dsPIC
DSCs allows quick application development on fully functional systems. Most boards include prototyping
PIC18F26/45/46Q10
Development Support
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 767
areas for adding custom circuitry and provide application firmware and source code for examination and
modification.
The boards support a variety of features, including LEDs, temperature sensors, switches, speakers,
RS-232 interfaces, LCD displays, potentiometers and additional EEPROM memory.
The demonstration and development boards can be used in teaching environments, for prototyping
custom circuits and for learning about various microcontroller applications.
In addition to the PICDEM and dsPICDEM demonstration/development board series of circuits,
Microchip has a line of evaluation kits and demonstration software for analog filter design, KeeLoq®
security ICs, CAN, IrDA®, PowerSmart battery management, SEEVAL® evaluation system, Sigma-Delta
ADC, flow rate sensing, plus many more.
Also available are starter kits that contain everything needed to experience the specified device. This
usually includes a single application and debug capability, all on one board.
Check the Microchip webpage (www.microchip.com) for the complete list of demonstration, development
and evaluation kits.
38.12 Third-Party Development Tools
Microchip also offers a great collection of tools from third-party vendors. These tools are carefully
selected to offer good value and unique functionality.
Device Programmers and Gang Programmers from companies, such as SoftLog and CCS
Software Tools from companies, such as Gimpel and Trace Systems
Protocol Analyzers from companies, such as Saleae and Total Phase
Demonstration Boards from companies, such as MikroElektronika, Digilent® and Olimex
Embedded Ethernet Solutions from companies, such as EZ Web Lynx, WIZnet and IPLogika®
PIC18F26/45/46Q10
Development Support
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 768
39. Electrical Specifications
39.1 Absolute Maximum Ratings(†)
Parameter Rating
Ambient temperature under bias -40°C to +125°C
Storage temperature -65°C to +150°C
Voltage on pins with respect to VSS
on VDD pin: -0.3V to +6.5V
on MCLR pin: -0.3V to +9.0V
on all other pins: -0.3V to (VDD + 0.3V)
Maximum current(1)
on VSS pin -40°C ≤ TA ≤ +85°C 350 mA
85°C < TA ≤ +125°C 120 mA
on VDD pin (28-pin devices) -40°C ≤ TA ≤ +85°C 250 mA
85°C < TA ≤ +125°C 85 mA
on VDD pin (40-pin devices) -40°C ≤ TA ≤ +85°C 350 mA
85°C < TA ≤ +125°C 120 mA
on any standard I/O pin ±50 mA
Clamp current, IK (VPIN < 0 or VPIN > VDD)±20 mA
Total power dissipation(2) 800 mW
Important: 
1. Maximum current rating requires even load distribution across I/O pins. Maximum current
rating may be limited by the device package power dissipation characterizations, see
Thermal Characteristics to calculate device specifications.
2. Power dissipation is calculated as follows:
PDIS = VDD x {IDD - Σ IOH} + Σ {(VDD - VOH) x IOH} + Σ (VOI x IOL)
3. Internal Power Dissipation is calculated as follows: PINTERNAL = IDD x VDD where IDD is
current to run the chip alone without driving any load on the output pins.
4. I/O Power Dissipation is calculated as follows: PI/O =Σ(IOL*VOL)+Σ(IOH*(VDD-VOH))
5. Derated Power is calculated as follows: PDER = PDMAX(TJ-TA)/θJA where TA=Ambient
Temperature, TJ = Junction Temperature.
NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage
to the device. This is a stress rating only and functional operation of the device at those or any other
conditions above those indicated in the operation listings of this specification is not implied. Exposure
above maximum rating conditions for extended periods may affect device reliability.
39.2 Standard Operating Conditions
The standard operating conditions for any device are defined as:
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 769
Operating Voltage: VDDMIN ≤ VDD ≤ VDDMAX
Operating Temperature:
TA_MIN ≤ TA ≤ TA_MAX
Parameter Ratings
VDD — Operating Supply Voltage(1) VDDMIN +1.8V
VDDMAX +5.5V
TA — Operating Ambient Temperature Range
Industrial Temperature TA_MIN -40°C
TA_MAX +85°C
Extended Temperature TA_MIN -40°C
TA_MAX +125°C
Figure 39-1. Voltage Frequency Graph, -40°C ≤ TA≤ +125°C
0
Frequency (MHz)
VDD (V)
1.8
64
5.5
3216104
Rev. 30-000069B
6/1/2017
Note: 
1. The shaded region indicates the permissible combinations of voltage and frequency.
2. Refer to 39.4.1 External Clock/Oscillator Timing Requirements for each Oscillator mode’s
supported frequencies.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 770
39.3 DC Characteristics
39.3.1 Supply Voltage
Table 39-1. 
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Characteristic Min. Typ.† Max. Units Conditions
Supply Voltage
D002 VDD 1.8 5.5 V
RAM Data Retention(1)
D003 VDR 1.7 V Device in
SLEEP mode
Power-on Reset Release Voltage(2)
D004 VPOR 1.6 V BOR and
LPBOR
disabled(3)
Power-on Reset Rearm Voltage(2)
D005 VPORR 1 V BOR and
LPBOR
disabled(3)
VDD Rise Rate to ensure internal Power-on Reset signal(2)
D006 SVDD 0.05 V/ms BOR and
LPBOR
disabled(3)
Data in “Typ.” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
2. See the following figure, POR and POR REARM with Slow Rising VDD.
3. See 39.4.5 Reset, WDT, Oscillator Start-up Timer, Power-up Timer, Brown-Out Reset and Low-
Power Brown-Out Reset Specifications for BOR and LPBOR trip point information.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 771
Figure 39-2. POR and POR Rearm with Slow Rising VDD
VDD
VPOR
VPORR
VSS
VSS
NPOR(1)
TPOR(2)
POR REARM
TVLOW(3)
SVDD
Rev. 30-000071A
4/6/2017
Note: 
1. When NPOR is low, the device is held in Reset.
2. TPOR 1 μs typical.
3. TVLOW 2.7 μs typical.
39.3.2 Supply Current (IDD)(1,2,4)
Table 39-2. 
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Device
Characteristics
Min. Typ.† Max. Units Conditions
VDD Note
D100 IDDXT4 XT = 4 MHz 490 770 μA 3.0V
D100A IDDXT4 XT = 4 MHz 410 μA 3.0V PMD’s all
1’s
D101 IDDHFO16 HFINTOSC = 16
MHz
1.3 1.7 mA 3.0V
D101A IDDHFO16 HFINTOSC = 16
MHz
1.1 mA 3.0V PMD’s all
1’s
D102 IDDHFOPLL HFINTOSC = 64
MHz
4.4 5.8 mA 3.0V
D102A IDDHFOPLL HFINTOSC = 64
MHz
3.4 mA 3.0V PMD’s all
1’s
D103 IDDHSPLL64 HS+PLL = 64 MHz 4.3 5.7 mA 3.0V
D103A IDDHSPLL64 HS+PLL = 64 MHz 3.3 mA 3.0V PMD’s all
1’s
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 772
...........continued
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Device
Characteristics
Min. Typ.† Max. Units Conditions
VDD Note
D104 IDDIDLE IDLE mode,
HFINTOSC = 16
MHz
0.6 mA 3.0V
D105 IDDDOZE
(3) DOZE mode,
HFINTOSC = 16
MHz, Doze Ratio =
16
0.7 mA 3.0V
Data in “Typ.” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. The test conditions for all IDD measurements in active operation mode are: OSC1 = external
square wave, from
rail-to-rail; all I/O pins are outputs driven low; MCLR = VDD; WDT disabled.
2. The supply current is mainly a function of the operating voltage and frequency. Other factors, such
as I/O pin loading and switching rate, oscillator type, internal code execution pattern and
temperature, also have an impact on the current consumption.
3. IDDDOZE = [IDDIDLE*(N-1)/N] + IDDHFO16/N where N = DOZE Ratio (see CPUDOZE register).
4. PMD bits are all in the default state, no modules are disabled.
Related Links
6.6.2 CPUDOZE
39.3.3 Power-Down Current (IPD)(1,2)
Table 39-3. 
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Device
Characteristics
Min. Typ.† Max.
+85°C
Max.
+125°C
Units Conditions
VDD VREGPM Note
D200 IPD IPD Base b'11' Reserved
D200A IPD IPD Base 0.6 4.0 12 μA 3.0V b'10'
D200B 50 90 μA 3.0V b'01'
D200C 170 280 μA 3.0V b'00'
D201 IPD_WDT Low-Frequency
Internal
Oscillator/WDT
0.9 5.0 13 μA 3.0V b'10'
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 773
...........continued
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Device
Characteristics
Min. Typ.† Max.
+85°C
Max.
+125°C
Units Conditions
VDD VREGPM Note
D202* IPD_SOSC Secondary
Oscillator
(SOSC)
1.6 4.3 10 μA 3.0V b'10'
D203 IPD_LPBOR Low-Power
Brown-out
Reset (LPBOR)
0.9 5.0 13 μA 3.0V b'10'
D204 IPD_FVR FVR 70 105 110 μA 3.0V b'10' or
b'01'
FVRCON
= 0x81 or
0x84
D205 IPD_BOR Brown-out
Reset (BOR)
30 60 63 μA 3.0V b'10'
D206 IPD_HLVD High/Low
Voltage Detect
(HLVD)
22 μA 3.0V b'10'
D207 IPD_ADCA ADC - Active 330 μA 3.0V b'10' or
b'01'
ADC is
converting
(4)
D208 IPD_CMP Comparator 60 85 90 μA 3.0V b'10'
* - These parameters are characterized but not tested.
† - Data in “Typ.” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. The peripheral current is the sum of the base IDD and the additional current consumed when this
peripheral is enabled. The peripheral ∆ current can be determined by subtracting the base IDD or
IPDcurrent from this limit. Max. values should be used when calculating total current consumption.
2. The power-down current in Sleep mode does not depend on the oscillator type. Power-down
current is measured with the part in Sleep mode with all I/O pins in high-impedance state and tied
to VSS.
3. All peripheral currents listed are on a per-peripheral basis if more than one instance of a
peripheral is available.
4. ADC clock source is FRC.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 774
39.3.4 I/O Ports
Table 39-4. 
Standard Operating Conditions (unless otherwise stated)
Param. No. Sym. Device
Characteristics
Min. Typ.† Max. Units Conditions
Input Low Voltage
VIL I/O PORT:
D300 with TTL buffer 0.8 V 4.5V≤VDD≤5.5V
D301 0.15 VDD V 1.8V≤VDD<4.5V
D302 with Schmitt
Trigger buffer
0.2 VDD V 2.0V≤VDD≤5.5V
D303 with I2C levels 0.3 VDD V
D304 with SMBus levels 0.8 V 2.7V≤VDD≤5.5V
D305 MCLR 0.2 VDD V
High Low Voltage
VIH I/O PORT:
D320 with TTL buffer 2.0 V 4.5V≤VDD≤5.5V
D321 0.25 VDD+0.8 V 1.8V≤VDD<4.5V
D322 with Schmitt
Trigger buffer
0.8VDD V 2.0V≤VDD≤5.5V
D323 with I2C levels 0.7 VDD V
D324 with SMBus levels 2.1 V 2.7V≤VDD≤5.5V
D325 MCLR 0.7 VDD V
Input Leakage Current(1)
D340 IIL I/O PORTS ±5 ±125 nA VSS≤VPIN≤VDD,
Pin at high-
impedance, 85°C
D341 ±5 ±1000 nA VSS≤VPIN≤VDD,
Pin at high-
impedance, 125°C
D342 MCLR(2) ±50 ±200 nA VSS≤VPIN≤VDD,
Pin at high-
impedance, 85°C
Weak Pull-up Current
D350 IPUR 80 140 200 μA VDD=3.0V, VPIN=VSS
Output Low Voltage
D360 VOL I/O PORTS 0.6 V IOL=10.0 mA,
VDD=3.0V
Output High Voltage
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 775
...........continued
Standard Operating Conditions (unless otherwise stated)
Param. No. Sym. Device
Characteristics
Min. Typ.† Max. Units Conditions
D370 VOH I/O PORTS VDD-0.7 V IOH=6.0 mA,
VDD=3.0V
All I/O Pins
D380 CIO 5 50 pF
Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note: 
1. Negative current is defined as current sourced by the pin.
2. The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels
represent normal operating conditions. Higher leakage current may be measured at different input voltages.
39.3.5 Memory Programming Specifications
Table 39-5. 
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Device Characteristics Min. Typ† Max. Units Conditions
Data EEPROM Memory Specifications
MEM20 EDDataEE Byte Endurance 100k E/W -40°C≤TA≤+85°C
MEM21 TD_RET Characteristic Retention
40 Year
Provided no other
specifications are
violated
MEM22 ND_REF Total Erase/Write Cycles
before Refresh
1M 10M E/W -40°C≤ TA≤+85°C
MEM23 VD_RW VDD for Read or Erase/Write
operation VDDMIN VDDMAX V
MEM24 TD_BEW Byte Erase and Write Cycle
Time
10 11 ms
Program Flash Memory Specifications
MEM30 EPFlash Memory Cell
Endurance 10k E/W -40°C≤Ta≤+85°C
(Note 1)
MEM32 TP_RET Characteristic Retention
40 Year
Provided no other
specifications are
violated
MEM33 VP_RD VDD for Read operation VDDMIN VDDMAX V
MEM34 VP_REW VDD for Row Erase or Write
operation VDDMIN VDDMAX V
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 776
...........continued
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Device Characteristics Min. Typ† Max. Units Conditions
MEM35 TP_REW Self-Timed Sector Write 6 10 ms
MEM36 TSE Self-Timed Sector Erase 10 14 ms
MEM37 TP_WRD Self-Timed Word Write 55 80 μs
Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. Flash Memory Cell Endurance for the Flash memory is defined as: One Row Erase operation and
one Self-Timed Write.
39.3.6 Thermal Characteristics
Table 39-6. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Typ. Units Conditions
TH01 θJA Thermal Resistance Junction to
Ambient
60 °C/W 28-pin SPDIP package
80 °C/W 28-pin SOIC package
90 °C/W 28-pin SSOP package
27.5 °C/W 28-pin VQFN 4x4 mm package
27.5 °C/W 28-pin QFN 6x6 mm package
47.2 °C/W 40-pin PDIP package
28.9 °C/W 40-pin QFN package
46 °C/W 44-pin TQFP package
TH03 TJMAX Maximum Junction Temperature 150 °C
Note: 
1. See "Absolute Maximum Ratings" for total power dissipation.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 777
39.4 AC Characteristics
Figure 39-3. Load Conditions
Filename: 10-000133A.vsd
Title: LOAD CONDITION
Last Edit: 8/1/2013
First Used: PIC16F1508/9
Note:
Load Condition
Legend: CL=50 pF for all pins
Pin
CL
VSS
Rev. 10-000133A
8/1/2013
39.4.1 External Clock/Oscillator Timing Requirements
Figure 39-4. Clock Timing
CLKIN
CLKOUT
Q4 Q1 Q2 Q3 Q4 Q1
OS1
OS20
(CLKOUT Mode)
OS2
OS2
Rev. 30-000072A
4/6/2017
Note:  See table below.
Table 39-7. 
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
ECL Oscillator
OS1 FECL Clock Frequency 1 MHz
OS2 TECL_DC Clock Duty Cycle 40 60 %
ECM Oscillator
OS3 FECM Clock Frequency 16 MHz
OS4 TECM_DC Clock Duty Cycle 40 60 %
ECH Oscillator
OS5 FECH Clock Frequency 64 MHz
OS6 TECH_DC Clock Duty Cycle 40 60 %
LP Oscillator
OS7 FLP Clock Frequency 100 kHz Note 4
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 778
...........continued
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
XT Oscillator
OS8 FXT Clock Frequency 4 MHz Note 4
HS Oscillator
OS9 FHS Clock Frequency 20 MHz VDD>2.5V
Note 4
Secondary Oscillator
OS10 FSEC Clock Frequency 32.4 32.768 33.1 kHz Note 4
System Oscillator
OS20 FOSC System Clock
Frequency
64 MHz (Note 2, Note
3)
OS21 FCY Instruction
Frequency
FOSC/4 MHz
OS22 TCY Instruction Period 62.5 1/FCY ns
Note: 
1. Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified
values are based on characterization data for that particular oscillator type under standard
operating conditions with the device executing code. Exceeding these specified limits may result
in an unstable oscillator operation and/or higher than expected current consumption. All devices
are tested to operate at “min” values with an external clock applied to OSC1 pin. When an
external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices.
2. The system clock frequency (FOSC) is selected by the “main clock switch controls” as described
in the “Power Saving Operation Modes” section.
3. The system clock frequency (FOSC) must meet the voltage requirements defined in the "Standard
Operating Conditions" section.
4. LP, XT and HS oscillator modes require an appropriate crystal or resonator to be connected to the
device. For clocking the device with the external square wave, one of the EC mode selections
must be used.
Related Links
39.2 Standard Operating Conditions
6. Power-Saving Operation Modes
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 779
39.4.2 Internal Oscillator Parameters(1)
Table 39-8. 
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
OS50 FHFOSC Precision
Calibrated
HFINTOSC
Frequency
4
8
12
16
32
48
64
MHz (Note 2)
OS51 FHFOSCLP Low-Power
Optimized
HFINTOSC
Frequency
1
2
MHz
MHz
Fundamental
Freq.1 MHz
Fundamental
Freq. 2 MHz
OS52 FMFOSC Internal Calibrated
MFINTOSC
Frequency
500 kHz
OS53* FLFOSC Internal LFINTOSC
Frequency
31 kHz
OS54* THFOSCST HFINTOSC Wake-
up from Sleep
Start-up Time
11
100
20
μs
μs
VREGPM=0x
VREGPM=1x
OS56 TLFOSCST LFINTOSC Wake-
up from Sleep
Start-up Time
0.3 ms
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as
close to the device as possible. 0.1 μF and 0.01 μF values in parallel are recommended.
2. See the figure below.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 780
Figure 39-5. Precision Calibrated HFINTOSC Frequency Accuracy Over Device VDD and
Temperature
125
2.0
0
60
85
VDD (V)
4.0 5.04.5
Temperature (°C)
2.3 3.0 3.5 5.5
1.8
-40
± 5%
± 2%
± 5%
± 3%
Rev. 30-000073A
9/7/2017
39.4.3 PLL Specifications
Table 39-9. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
PLL01 FPLLIN PLL Input
Frequency Range
4 16 MHz
PLL02 FPLLOUT PLL Output
Frequency Range
16 64 MHz (Note 1)
PLL03* FPLLST PLL Lock Time 10 μs
PLL04* FPLLJIT PLL Output
Frequency Stability
-0.25 0.25 %
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. The output frequency of the PLL must meet the FOSC requirements listed in Parameter D002.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 781
39.4.4 I/O and CLKOUT Timing Specifications
Figure 39-6. CLKOUT and I/O Timing
FOSC
CLKOUT
I/O pin
(Input)
I/O pin
(Output)
Q4 Q1 Q2 Q3
IO1
IO8
IO3
IO7, IO8
IO10
IO5
IO4
IO2
IO7
Old Value New Value
Write Fetch Read ExecuteCycle
Rev. 30-000074A
4/6/2017
Table 39-10. I/O and CLKOUT Timing Specifications
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
IO1* TCLKOUTH CLKOUT rising edge delay (rising
edge FOSC (Q1 cycle) to falling edge
CLKOUT
70 ns
IO2* TCLKOUTL CLKOUT falling edge delay (rising
edge FOSC (Q3 cycle) to rising edge
CLKOUT
72 ns
IO3* TIO_VALID Port output valid time (rising edge
FOSC (Q1 cycle) to port valid)
50 70 ns
IO4* TIO_SETUP Port input setup time (Setup time
before rising edge FOSC – Q2 cycle)
20 ns
IO5* TIO_HOLD Port input hold time (Hold time after
rising edge FOSC – Q2 cycle)
50 ns
IO6* TIOR_SLREN Port I/O rise time, slew rate enabled 25 ns VDD=3.0V
IO7* TIOR_SLRDIS Port I/O rise time, slew rate disabled 5 ns VDD=3.0V
IO8* TIOF_SLREN Port I/O fall time, slew rate enabled 25 ns VDD=3.0V
IO9* TIOF_SLRDIS Port I/O fall time, slew rate disabled 5 ns VDD=3.0V
IO10* TINT INT pin high or low time to trigger an
interrupt
25 ns
IO11* TIOC Interrupt-on-Change minimum high or
low time to trigger interrupt
25 ns
* - These parameters are characterized but not tested.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 782
39.4.5 Reset, WDT, Oscillator Start-up Timer, Power-up Timer, Brown-Out Reset and Low-Power Brown-
Out Reset Specifications
Figure 39-7. Reset, Watchdog Timer, Oscillator Start-up Timer and Power-up Timer Timing
VDD
MCLR
Internal
POR
PWRT
Time-out
OSC
Start-up Time
Internal Reset(1)
Watchdog Timer
RST04
RST05
RST01
RST03
RST02
I/O pins
RST02
Reset(1)
Rev. 30-000075A
4/6/2017
Note: 
1. Asserted low.
Figure 39-8. Brown-out Reset Timing and Characteristics
VBOR
VDD
(Device in Brown-out Reset) (Device not in Brown-out Reset)
RST04(1)
Reset
(due to BOR)
VBOR and VHYST
RST08
Rev. 30-000076A
4/6/2017
Note: 
1. Only if PWRTE bit in the Configuration Word register is programmed to ‘1’; 2 ms delay if PWRTE =
0.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 783
Table 39-11. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
RST01* TMCLR MCLR Pulse Width
Low to ensure
Reset
2 μs
RST02* TIOZ I/O high-impedance
from Reset
detection
2 μs
RST03 TWDT Watchdog Timer
Time-out Period
16 ms WDTCPS=00100
RST04* TPWRT Power-up Timer
Period
65 ms
RST05 TOST Oscillator Start-up
Timer Period(1,2)
1024 TOSC
RST06 VBOR Brown-out Reset
Voltage
2.7
2.55
2.3
1.8
2.85
2.7
2.45
1.9
3.0
2.85
2.6
2.1
V
V
V
V
BORV=00
BORV=01
BORV=10
BORV=11
RST07 VBORHYS Brown-out Reset
Hysteresis
60 mV BORV=00
RST08 TBORDC Brown-out Reset
Response Time
3 μs
RST09 VLPBOR Low-Power Brown-
out Reset Voltage
1.8 1.9 2.2 V
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. By design, the Oscillator Start-up Timer (OST) counts the first 1024 cycles, independent of
frequency.
2. To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the
device as possible. 0.1 μF and 0.01 μF values in parallel are recommended.
39.4.6 High/Low-Voltage Detect Characteristics
Table 39-12. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. Max. Units Conditions
HLVD01 VDET Voltage Detect 1.90 V HLVDSEL=b'0000'
2.10 V HLVDSEL=b'0001'
2.25 V HLVDSEL=b'0010'
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 784
...........continued
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. Max. Units Conditions
2.50 V HLVDSEL=b'0011'
2.60 V HLVDSEL=b'0100'
2.75 V HLVDSEL=b'0101'
2.90 V HLVDSEL=b'0110'
3.15 V HLVDSEL=b'0111'
3.35 V HLVDSEL=b'1000'
3.60 V HLVDSEL=b'1001'
3.75 V HLVDSEL=b'1010'
4.00 V HLVDSEL=b'1011'
4.20 V HLVDSEL=b'1100'
4.35 V HLVDSEL=b'1101'
4.65 V HLVDSEL=b'1110'
39.4.7 Analog-to-Digital Converter (ADC) Accuracy Specifications(1,2)
Table 39-13. 
Standard Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = 25°C, TAD = 1μs
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
AD01 NRResolution 10 bit
AD02 EIL Integral Non-Linearity
Error
±0.1 ±1.0 LSb ADCREF+=3.0V,
ADCREF- = 0V
AD03 EDL Differential Non-Linearity
Error
±0.1 ±1.0 LSb ADCREF+=3.0V,
ADCREF- = 0V
AD04 EOFF Offset Error 0.5 ±2.0 LSb ADCREF+=3.0V,
ADCREF- = 0V
AD05 EGN Gain Error ±0.2 ±2.0 LSb ADCREF+=3.0V,
ADCREF- = 0V
AD06 VADREF ADC Reference Voltage
(ADREF+ - ADREF-)
1.8 VDD V
AD07 VAIN Full-Scale Range ADREF- ADREF+ V
AD08 ZAIN Recommended
Impedance of Analog
Voltage Source
10
AD09 RVREF ADC Voltage Reference
Ladder Impedance
50 (Note 3)
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 785
...........continued
Standard Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = 25°C, TAD = 1μs
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. Total Absolute Error is the sum of the offset, gain and integral non-linearity (INL) errors.
2. The ADC conversion result never decreases with an increase in the input and has no missing
codes.
3. This is the impedance seen by the VREF pads when the external reference pads are selected.
39.4.8 Analog-to-Digital Converter (ADC) Conversion Timing Specifications
Table 39-14. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
AD20 TAD ADC Clock Period 1 9 μs Using FOSC as the ADC
clock source ADOCS = 0
AD21 1 2 6 μs Using FRC as the ADC
clock source ADOCS = 1
AD22 TCNV Conversion Time(1) 11+3TCY TAD Set of GO/DONE bit to
Clear of GO/ DONE bit
AD23 TACQ Acquisition Time 2 μs
AD24 THCD Sample-and-Hold
Capacitor Disconnect
Time
μs FOSC-based clock source
FRC-based clock source
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. Does not apply for the ADCRC oscillator.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 786
Figure 39-9. ADC Conversion Timing (ADC Clock FOSC-Based)
Rev. 10-000321B
4/16/2019
BSF ADCON0, GO
GO
Sample
ADC_clk
ADIF
ADRES OLD DATA
AD20
NEW DATA
AD22
1 TCY
DONE
Sampling Stopped
AD24
1 TCY
1 TCY
Figure 39-10. ADC Conversion Timing (ADC Clock from ADCRC)
Rev. 10-000328B
4/16/2019
BSF ADCON0, GO
GO
Sample
ADC_clk
ADIF
ADRES OLD DATA
AD21
NEW DATA
AD22
1 TCY
DONE
Sampling Stopped
AD24
2 TCY
(1)
Note: 
1. If the ADC clock source is selected as ADCRC, a time of TCY is added before the ADC clock starts.
This allows the SLEEP instruction to be executed.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 787
39.4.9 Comparator Specifications
Table 39-15. 
Standard Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = 25°C
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
CM01 VIOFF Input Offset
Voltage
±30 mV VICM=VDD/2
CM02 VICM Input Common
Mode Range
GND VDD V
CM03 CMRR Common Mode
Input Rejection
Ratio
50 dB
CM04 VHYST Comparator
Hysteresis
10 25 40 mV
CM05 TRESP(1) Response Time,
Rising Edge
300 600 ns
Response Time,
Falling Edge
220 500 ns
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. Response time measured with one comparator input at VDD/2, while the other input transitions
from VSS to VDD.
39.4.10 5-Bit DAC Specifications
Table 39-16. 
Standard Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = 25°C
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
DSB01 VLSB Step-Size (VDACREF+-
VDACREF-)/32
V
DSB02 VACC Absolute Accuracy ±0.5 LSb
DSB03* RUNIT Unit Resistor
Value
5000 Ω
DSB04* TST Settling Time(1) 10 μs
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 788
...........continued
Standard Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = 25°C
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. Settling time measured while DACR<4:0> transitions from ‘00000’ to ‘01111’.
39.4.11 Fixed Voltage Reference (FVR) Specifications
Table 39-17. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
FVR01 VFVR1 1x Gain (1.024V) -4 +4 % VDD≥2.5V, -40°C to 85°C
FVR02 VFVR2 2x Gain (2.048V) -4 +4 % VDD≥2.5V, -40°C to 85°C
FVR03 VFVR4 4x Gain (4.096V) -4 +4 % VDD≥4.75V, -40°C to 85°C
FVR04 TFVRST FVR Start-up Time 25 μs
39.4.12 Zero-Cross Detect (ZCD) Specifications
Table 39-18. 
Standard Operating Conditions (unless otherwise stated)
VDD = 3.0V, TA = 25°C
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
ZC01 VPINZC Voltage on Zero
Cross Pin
0.9 V
ZC02 IZCD_MAX Maximum source or
sink current
600 μA
ZC03 TRESPH Response Time,
Rising Edge
1 μs
TRESPL Response Time,
Falling Edge
1 μs
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 789
39.4.13 Timer0 and Timer1 External Clock Requirements
Table 39-19. 
Standard Operating Conditions (unless otherwise stated)
Operating Temperature: -40°C≤TA≤+125°C
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
40* TT0H T0CKI
High
Pulse
Width
No Prescaler 0.5TCY
+20
ns
With Prescaler 10 ns
41* TT0L T0CKI
Low
Pulse
Width
No Prescaler 0.5TCY
+20
ns
With Prescaler 10 ns
42* TT0P T0CKI Period Greater
of: 20 or
(TCY
+40)/N
ns N = Prescale
value
45* TT1H T1CKI
High
Time
Synchronous,
No Prescaler
0.5TCY
+20
ns
Synchronous,
with Prescaler
15 ns
Asynchronous 30 ns
46* TT1L T1CKI
Low Time
Synchronous,
No Prescaler
0.5TCY
+20
ns
Synchronous,
with Prescaler
15 ns
Asynchronous 30 ns
47* TT1P T1CKI
Input
Period
Synchronous Greater
of: 30 or
(TCY
+40)/N
ns N = Prescale
value
Asynchronous 60 ns
49* TCKEZTMR1 Delay from External Clock
Edge to Timer Increment
2 TOSC 7 TOSC Timers in
Sync mode
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 790
Figure 39-11. Timer0 and Timing1 External Clock Timings
T0CKI
T1CKI
40 41
42
45 46
47 49
TMR0 or
TMR1
Rev. 30-000079A
4/6/2017
39.4.14 Capture/Compare/PWM Requirements (CCP)
Table 39-20. 
Standard Operating Conditions (unless otherwise stated)
Operating Temperature: -40°C≤TA≤+125°C
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
CC01* TCCL CCPx
Input Low
Time
No Prescaler 0.5TCY+20 ns
With
Prescaler
20 ns
CC02* TCCH CCPx
Input High
Time
No Prescaler 0.5TCY+20 ns
With
Prescaler
20 ns
CC03* TCCP CCPx
Input
Period
(3TCY
+40)/N
ns N = Prescale
value
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 791
Figure 39-12. Capture/Compare/PWM Timings (CCP)
(Capture mode)
CC01 CC02
CC03
CCPx
Rev. 30-000080A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
39.4.15 EUSART Synchronous Transmission Requirements
Table 39-21. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Max. Units Conditions
US120 TCKH2DTV SYNC XMIT (Master and Slave)
Clock high to data-out valid
80 ns 3.0V≤VDD≤5.5V
100 ns 1.8V≤VDD≤5.5V
US121 TCKRF Clock out rise time and fall time
(Master mode)
45 ns 3.0V≤VDD≤5.5V
50 ns 1.8V≤VDD≤5.5V
US122 TDTRF Data-out rise time and fall time 45 ns 3.0V≤VDD≤5.5V
50 ns 1.8V≤VDD≤5.5V
Figure 39-13. EUSART Synchronous Transmission (Master/Slave) Timing
US121 US121
US120 US122
CK
DT
Rev. 30-000081A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
39.4.16 EUSART Synchronous Receive Requirements
Table 39-22. 
Standard Operating Conditions (unless otherwise stated)
Param No. Sym. Characteristic Min. Max. Units Conditions
US125 TDTV2CKL SYNC RCV (Master and Slave)
Data-setup before CK ↓ (DT hold time)
10 ns
US126 TCKL2DTL Data-hold after CK ↓ (DT hold time) 15 ns
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 792
Figure 39-14. EUSART Synchronous Receive (Master/Slave) Timing
US125
US126
CK
DT
Rev. 30-000082A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
39.4.17 SPI Mode Requirements
Table 39-23. 
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
SP70* TSSL2SCH,
TSSL2SCL
SS↓ to SCK↓ or
SCK↑ input
2.25*TCY ns
SP71* TSCH SCK input high time
(Slave mode)
TCY + 20 ns
SP72* TSCL SCK input low time
(Slave mode)
TCY + 20 ns
SP73* TDIV2SCH,
TDIV2SCL
Setup time of SDI
data input to SCK
edge
100 ns
SP74* TSCH2DIL,
TSCL2DIL
Hold time of SDI data
input to SCK edge
100 ns
SP75* TDOR SDO data output rise
time
10 25 ns 3.0V≤VDD≤5.5V
25 50 ns 1.8V≤VDD≤5.5V
SP76* TDOF SDO data output fall
time
10 25 ns
SP77* TSSH2DOZ SS↑ to SDO output
high-impedance
10 50 ns
SP78* TSCR SCK output rise time
(Master mode)
10 25 ns 3.0V≤VDD≤5.5V
25 50 ns 1.8V≤VDD≤5.5V
SP79* TSCF SCK output fall time
(Master mode)
10 25 ns
SP80* TSCH2DOV,
TSCL2DOV
SDO data output
valid after SCK edge
50 ns 3.0V≤VDD≤5.5V
145 ns 1.8V≤VDD≤5.5V
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 793
...........continued
Standard Operating Conditions (unless otherwise stated)
Param
No.
Sym. Characteristic Min. Typ. † Max. Units Conditions
SP81* TDOV2SCH,
TDOV2SCL
SDO data output
setup to SCK edge
1 TCY ns
SP82* TSSL2DOV SDO data output
valid after SS↓ edge
50 ns
SP83* TSCH2SSH,
TSCL2SSH
SS ↑after SCK
edge
1.5 TCY
+ 40
ns
* - These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Figure 39-15. SPI Master Mode Timing (CKE = 0, SMP = 0)
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
SP81
SP71 SP72
SP73
SP74
SP75, SP76
SP78
SP79
SP80
SP79
SP78
MSb LSb
bit 6 - - - - - -1
MSb In LSb In
bit 6 - - - -1
Rev. 30-000083A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 794
Figure 39-16. SPI Master Mode Timing (CKE = 1, SMP = 1)
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
SP81
SP71 SP72
SP74
SP75, SP76
SP78
SP80
MSb
SP79
SP73
MSb In
bit 6 - - - - - -1
LSb In
bit 6 - - - -1
LSb
Rev. 30-000084A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
Figure 39-17. SPI Slave Mode Timing (CKE = 0)
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
SP70
SP71 SP72
SP73
SP74
SP75, SP76 SP77
SP78
SP79
SP80
SP79
SP78
MSb LSb
bit 6 - - - - - -1
MSb In bit 6 - - - -1 LSb In
SP83
Rev. 30-000085A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 795
Figure 39-18. SPI Slave Mode Timing (CKE = 1)
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
SP70
SP71 SP72
SP82
SP74
SP75, SP76
MSb bit 6 - - - - - -1 LSb
SP77
MSb In bit 6 - - - -1 LSb In
SP80
SP83
Rev. 30-000086A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
39.4.18 I2C Bus Start/Stop Bits Requirements
Table 39-24. 
Standard Operating Conditions (unless otherwise stated)
Param. No. Sym. Characteristic Min. Typ. † Max. Units Conditions
SP90* TSU:STA Start condition
Setup time
100 kHz
mode
4700 ns Only relevant for
Repeated Start Setup
time 400 kHz mode
600 condition
400 kHz
mode
600
SP91* THD:STA Start condition
Hold time
100 kHz
mode
4000 ns After this period, the
first clock Hold time
400 kHz mode 600
— — pulse is
generated
400 kHz
mode
600
SP92* TSU:STO Stop condition
Setup time
100 kHz
mode
4700 ns
400 kHz
mode
600
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 796
...........continued
Standard Operating Conditions (unless otherwise stated)
Param. No. Sym. Characteristic Min. Typ. † Max. Units Conditions
SP93* THD:STO Stop condition
Hold time
100 kHz
mode
4000 ns
400 kHz
mode
600
* - These parameters are characterized but not tested.
Figure 39-19. I2C Bus Start/Stop Bits Timing
SP91
SP92
SP93
SCL
SDA
Start
Condition
Stop
Condition
SP90
Rev. 30-000087A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
39.4.19 I2C Bus Data Requirements
Table 39-25. 
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Characteristic Min. Max. Units Conditions
SP100* THIGH Clock high
time
100 kHz
mode
4.0 μs Device must
operate at a
minimum of 1.5
MHz
400 kHz
mode
0.6 μs Device must
operate at a
minimum of 10
MHz
SSP
module
1.5TCY
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 797
...........continued
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Characteristic Min. Max. Units Conditions
SP101* TLOW Clock low
time
100 kHz
mode
4.7 μs Device must
operate at a
minimum of 1.5
MHz
400 kHz
mode
1.3 μs Device must
operate at a
minimum of 10
MHz
SSP
module
1.5TCY
SP102* TRSDA and
SCL rise
time
100 kHz
mode
1000 ns
400 kHz
mode
20
+ 0.1CB
300 ns CB is specified to
be from 10-400
pF
SP103* TFSDA and
SCL fall
time
100 kHz
mode
250 ns
400 kHz
mode
20
+ 0.1CB
250 ns CB is specified to
be from 10-400
pF
SP106* THD:DAT Data input
hold time
100 kHz
mode
0 ns
400 kHz
mode
0 0.9 μs
SP107* TSU:DAT Data input
setup time
100 kHz
mode
250 ns (Note 2)
400 kHz
mode
100 ns
SP109* TAA Output
valid from
clock
100 kHz
mode
3500 ns (Note 1)
400 kHz
mode
ns
SP110* TBUF Bus free
time
100 kHz
mode
4.7 μs Time the bus
must be free
before a new
transmission can
start
400 kHz
mode
1.3 μs
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 798
...........continued
Standard Operating Conditions (unless otherwise stated)
Param.
No.
Sym. Characteristic Min. Max. Units Conditions
SP111 CBBus capacitive loading pF
* - These parameters are characterized but not tested.
Note: 
1. As a transmitter, the device must provide this internal minimum delay time to bridge the undefined
region (min. 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop
conditions.
2. A Fast mode (400 kHz) I2C bus device can be used in a Standard mode (100 kHz) I2C bus
system, but the requirement TSU:DAT≥250 ns must then be met. This will automatically be the case
if the device does not stretch the low period of the SCL signal. If such a device does stretch the
low period of the SCL signal, it must output the next data bit to the SDA line TR max. + TSU:DAT =
1000 + 250 = 1250 ns (according to the Standard mode I2C bus specification), before the SCL line
is released.
Figure 39-20. I2C Bus Data Timing
SP90
SP91 SP92
SP100
SP101
SP103
SP106 SP107
SP109 SP109
SP110
SP102
SCL
SDA
In
SDA
Out
Rev. 30-000088A
4/6/2017
Note:  Refer to Figure 39-3 for load conditions.
39.4.20 Configurable Logic Cell (CLC) Characteristics
Table 39-26. 
Standard Operating Conditions (unless otherwise stated)
Operating Temperature: -40°C≤TA≤+125°C
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
CLC01* TCLCIN CLC input time 7 OS17 ns (Note1)
CLC02* TCLC CLC module input to
output propagation time
24 ns VDD = 1.8V
12 ns VDD > 3.6V
CLC03* TCLCOUT CLC output
time
Rise Time OS18 (Note1)
Fall Time OS19 (Note1)
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 799
...........continued
Standard Operating Conditions (unless otherwise stated)
Operating Temperature: -40°C≤TA≤+125°C
Param No. Sym. Characteristic Min. Typ. † Max. Units Conditions
CLC04* FCLCMAX CLC maximum
switching frequency
OS20
* - These parameters are characterized but not tested.
† - Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design
guidance only and are not tested.
Note: 
1. See “I/O and CLKOUT Timing Specifications” for OS7, OS8 and OS9 rise and fall times.
Figure 39-21. CLC Propagation Timing
LCx_in[n](1)
CLC
Output time
CLC
Input time LCx_out(1) CLCx
CLCxINn CLC
Module
CLC01 CLC02 CLC03
LCx_in[n](1) CLC
Output time
CLC
Input time LCx_out(1) CLCx
CLCxINn CLC
Module
Rev. 30-000153A
10/27/2017
PIC18F26/45/46Q10
Electrical Specifications
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 800
40. DC and AC Characteristics Graphs and Tables
Graphs and tables are not available at this time.
PIC18F26/45/46Q10
DC and AC Characteristics Graphs and Tables
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 801
41. Packaging Information
Package Marking Information
Legend: XX...X Customer-specific information or Microchip part number
Y Year code (last digit of calendar year)
YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code
P b- free JEDEC ®designator for Matte Tin (Sn)
*This package is Pb-free. The Pb-free JEDEC designator ( )
can be found on the outer packaging for this package.
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
3
e
3
e
Rev. 30-009000A
5/17/2017
28-Lead SPDIP (.300”) Example
PIC18F27Q10
1526017
3
e
/SP
Rev. 30-009028A
5/17/2017
28-Lead SOIC (7.50 mm) Example
YYWWNNN
XXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXX
PIC18F27Q10
3
e
/S
O
1526017
Rev. 30-009028B
5/17/2017
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 802
28-Lead SSOP (5.30 mm) Example
PIC18F27Q10
1526017
3
e
/SS
Rev. 30-009028C5/17/2017
28-Lead QFN (6x6 mm) Example
XXXXXXXX
XXXXXXXX
YYWWNNN
PIN 1 PIN 1
18F27Q10
/ML
1526017
3
e
Rev. 30-009028D
5/17/2017
28-Lead VQFN (4x4x1 mm) Example
PIN 1 PIN 1
/MV
526017
3
e
PIC18
F27Q10
Rev. 30-009028F4/2/2018
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 803
40-Lead PDIP (600 mil) Example
XXXXXXXXXXXXXXXXXX
YYWWNNN
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
PIC18F45Q10
/P
3
e
1526017
Rev. 30-009040A5/17/2017
PIN 1 PIN 1
PIC18
/MP
1526017
3
e
F47Q10
40-Lead QFN (5x5x0.9 mm)
Rev. 30-009040D6/25/2018
Example
XXXXXXXXXX
YYWWNNN
XXXXXXXXXX
XXXXXXXXXX
18F47Q10
/PT
1526017
3
e
Rev. 30-009044B
5/18/2017
44-Lead TQFP (10x10x1 mm) Example
41.1 Package Details
The following sections give the technical details of the packages.
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 804
©2007 Microchip Technology Inc. DS00049AR-page 57
M
Packaging Diagrams and Parameters
28-Lead Skinny Plastic Dual In-Line (SP) – 300 mil Body [SPDIP]
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. § Significant Characteristic.
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" per side.
4. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Units INCHES
Dimension Limits MIN NOM MAX
Number of Pins N 28
Pitch e .100 BSC
Top to Seating Plane A .200
Molded Package Thickness A2 .120 .135 .150
Base to Seating Plane A1 .015
Shoulder to Shoulder Width E .290 .310 .335
Molded Package Width E1 .240 .285 .295
Overall Length D 1.345 1.365 1.400
Tip to Seating Plane L .110 .130 .150
Lead Thickness c .008 .010 .015
Upper Lead Width b1 .040 .050 .070
Lower Lead Width b .014 .018 .022
Overall Row Spacing § eB .430
NOTE 1
N
1 2
D
E1
eB
c
E
L
A2
eb
b1
A1
A
3
Microchip Technology Drawing C04-070B
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 805
DS00049BC-page 110 2009 Microchip Technology Inc.
M
Packaging Diagrams and Parameters
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 806
2009 Microchip Technology Inc. DS00049BC-page 109
M
Packaging Diagrams and Parameters
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 807
DS00049BC-page 104 2009 Microchip Technology Inc.
M
Packaging Diagrams and Parameters
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 808
Microchip Technology Drawing C04-073 Rev C Sheet 1 of 2
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
28-Lead Plastic Shrink Small Outline (SS) - 5.30 mm Body [SSOP]
© 2017 Microchip Technology Inc.
R
B
A
(DATUM B)
(DATUM A)
12
N
TOP VIEW
SIDE VIEW
E
0.15 C A B
C
SEATING
PLANE
D
A
28X b
E1
e
A2
A
A
0.10 C
28X
A1
VIEW A-A
L
H
(L1)
c
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 809
RECOMMENDED LAND PATTERN
Microchip Technology Drawing C04-2073 Rev B
28-Lead Plastic Shrink Small Outline (SS) - 5.30 mm Body [SSOP]
SILK SCREEN
12
28
C
E
X1
Y1
G1
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Notes:
Dimensioning and tolerancing per ASME Y14.5M
For best soldering results, thermal vias, if used, should be filled or tented to avoid solder loss during
reflow process
1.
2.
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
© 2017 Microchip Technology Inc.
R
Dimension Limits
Units
Contact Pitch
MILLIMETERS
0.65 BSC
MIN
E
MAX
Contact Pad Length (X28)
Contact Pad Width (X28)
Y1
X1
1.85
0.45
NOM
CContact Pad Spacing 7.00
Contact Pad to Center Pad (X26) G1 0.20
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 810
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 811
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 812
©2007 Microchip Technology Inc. DS00049AR-page 101
M
28-Lead Plastic Quad Flat, No Lead Package (ML) – 6x6 mm Body [QFN]
with 0.55 mm Contact Length
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Land Pattern (Footprint)
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 813
B
A
0.10 C
0.10 C
0.07 C A B
(DATUM B)
(DATUM A)
C
SEATING
PLANE
NOTE 1
1
2
N
2X TOP VIEW
SIDE VIEW
BOTTOM VIEW
NOTE 1
1
2
N
0.10 C A B
0.10 C A B
Microchip Technology Drawing C04-456 Rev A Sheet 1 of 2
2X
For the most current package drawings, please see the Microchip Packaging Specification locate d a t
http://www.microchip.com/packaging
Note:
28-Lead Very Thin Pla stic Quad Flat, No Lead (STX) - 4x4 mm Body [VQFN]
© 2017 Microchip Technology Inc.
D
E
(A3)
AA
0.08 C
28X
D2
(K)
28X b
e
L
CH
E2
0.10 C
With 2.65x2.65 mm Exposed Pad
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 814
Microchip Technology Drawing C04-456 Rev A Sheet 2 of 2
REF: Reference Dimension, usually without tolerance, for information purposes only.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
1.
2.
3.
Notes:
Pin 1 visual index feature may vary, but must be located within the hatched area.
Package is saw singulated
Dimensioning and tolera ncing per ASME Y14.5M
28-Lead Very Thin Pla stic Quad Flat, No Lead (STX) - 4x4 mm Body [VQFN]
For the most current package drawings, please see the Microchip Packaging Specification locate d a t
http://www.microchip.com/packaging
Note:
© 2017 Microchip Technology Inc.
Number of Ter m inals
Overall He ig ht
Terminal Width
Overall Width
Terminal Length
Exposed Pad Width
Terminal Thickness
Pitch
Standoff
Units
Dimension Limit s
A1
A
b
E2
A3
e
L
E
N0.40 BSC
0.127 REF
2.55
0.30
0.15
0.80
0.00
0.20
0.40
2.65
0.90
0.02
4.00 BSC
MILLIMETERS
MIN NOM
28
2.75
0.50
0.25
1.00
0.05
MAX
K 0.275 REFTerminal-to-Exposed-Pad
Overall Length
Expos ed Pad Length D
D2 2.55 4.00 BSC
2.65 2.75
CH 0.25Exposed Pa d Co rn er Chamf e r - -
With 2.65x2.65 mm Exposed Pad
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 815
RECOMMENDED LAND PATTERN
Dimension Limit s
Units
C2
Optional Center Pad Width
Contact Pad Spacing
Optional Center Pad Length
Contact Pitch
Y2
X2 2.75
2.75
MILLIMETERS
0.40 BSC
MIN
EMAX
4.00
Cont act Pad Length (X28)
Contact Pa d Width (X28) Y1
X1 0.80
0.20
NOM
C1Contact Pad Spacing 4.00
Cont act Pad to Center Pad (X28) G1 0.23
Thermal Via Diamete r V
Thermal Via Pitch EV 0.30
1.00
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Notes:
Dimensi oning and tolera ncing per ASME Y14.5M
For best soldering results, thermal vias, if used, should be filled or t e n ted to avoid s o ld er loss during
reflow process
1.
2.
For the most current package drawings, please see the Microchip Packaging Specification locate d a t
http://www.microchip.com/packaging
Note:
© 2017 Microchip Technology Inc.
Microchip Technology Drawing C04-2456 Rev A
28-Lead Very Thin Plastic Quad Flat, No Lead (STX) - 4x4 mm Body [VQFN]
C1
C2 EV
Y2
X2
EV
E
X1
Y1
G1
G2
ØV
SILK SCREEN
Contact Pad to Contact Pad (X24) G2 0.20
With 2.65x2.65 mm Exposed Pad
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 816
©2007 Microchip Technology Inc. DS00049AR-page 61
M
Packaging Diagrams and Parameters
40-Lead Plastic Dual In-Line (P) – 600 mil Body [PDIP]
Notes:
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. § Significant Characteristic.
3. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" per side.
4. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Units INCHES
Dimension Limits MIN NOM MAX
Number of Pins N 40
Pitch e .100 BSC
Top to Seating Plane A .250
Molded Package Thickness A2 .125 .195
Base to Seating Plane A1 .015
Shoulder to Shoulder Width E .590 .625
Molded Package Width E1 .485 .580
Overall Length D 1.980 2.095
Tip to Seating Plane L .115 .200
Lead Thickness c .008 .015
Upper Lead Width b1 .030 .070
Lower Lead Width b .014 .023
Overall Row Spacing § eB .700
N
NOTE 1
E1
D
1 2 3
A
A1 b1
b e
c
eB
E
L
A2
Microchip Technology Drawing C04-016B
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 817
0.20 C
0.20 C
(DATUM B)
(DATUM A)
C
SEATING
PLANE
1
2
N
2X
TOP VIEW
SIDE VIEW
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
NOTE 1
1
2
N
0.10 C A B
0.10 C A B
0.08 C
Microchip Technology Drawing C04-047-002A Sheet 1 of 2
40-Lead Plastic Quad Flat, No Lead Package (MP) - 5x5 mm Body [QFN]
D2
D
E
AB
40X b
e0.07 C A B
0.05 C
A
(A3)
With 3.7x3.7 mm Exposed Pad
E2
A1
0.10 C
K
L
2X
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 818
Microchip Technology Drawing C04-047-002A Sheet 2 of 2
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
Number of Terminals
Overall Height
Terminal Width
Overall Width
Overall Length
Terminal Length
Exposed Pad Width
Exposed Pad Length
Terminal Thickness
Pitch
Standoff
Units
Dimension Limits
A1
A
b
D
E2
D2
A3
e
L
E
N
0.40 BSC
0.20 REF
0.30
0.15
0.80
0.00
0.20
5.00 BSC
0.40
3.70 BSC
3.70 BSC
0.85
0.02
5.00 BSC
MILLIMETERS
MIN NOM
40
0.50
0.25
0.90
0.05
MAX
K -0.20 -
REF: Reference Dimension, usually without tolerance, for information purposes only.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
1.
2.
3.
No te s :
Pin 1 visual index feature may vary, but must be located within the hatched area.
Package is saw singulated
Dimensioning and tolerancing per ASME Y14.5M
Terminal-to-Exposed-Pad
40-Lead Plastic Quad Flat, No Lead Package (MP) - 5x5 mm Body [QFN]
With 3.7x3.7 mm Exposed Pad
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 819
RECOMMENDED LAND PATTERN
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
SILK SCREEN
Dimension Limits
Units
C1
Optional Center Pad Width
Contact Pad Spacing
Optional Center Pad Length
Contact Pitch
Y2
X2
3.80
3.80
MILLIMETERS
0.40 BSC
MIN
E
MAX
5.00
Contact Pad Length (X40)
Contact Pad Width (X40)
Y1
X1
0.80
0.20
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Notes:
1. Dimensioning and tolerancing per ASME Y14.5M
Microchip Technology Drawing C04-2047-002A
NOM
40-Lead Plastic Quad Flat, No Lead Package (MP) - 5x5 mm Body [QFN]
With 3.7x3.7 mm Exposed Pad
E
C1
C2 Y2
X2
Y1
X1
C2Contact Pad Spacing 5.00
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 820
B
A
0.20 H A B
0.20 H A B
44 X b
0.20 C A B
(DATUM B)
(DATUM A)
C
SEATING PLANE
2X
TOP VIEW
SIDE VIEW
BOTTOM VIEW
Microchip Technology Drawing C04-076C Sheet 1 of 2
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
e
NOTE 1
1 2
N
D
D1
EE1
2X
A2
A1
A
0.10 C
3
N
A A
0.20 C A B
4X 11 TIPS
1 2 3
44-Lead Plastic Thin Quad Flatpack (PT) - 10x10x1.0 mm Body [TQFP]
NOTE 1
NOTE 2
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 821
Microchip Technology Drawing C04-076C Sheet 2 of 2
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
L
(L1)
c
θ
SECTION A-A
H
Number of Leads
Overall Height
Lead Width
Overall Width
Overall Length
Lead Length
Molded Package Width
Molded Package Length
Molded Package Thickness
Lead Pitch
Standoff
Units
Dimension Limits
A1
A
b
D
E1
D1
A2
e
L
E
N
0.80 BSC
0.45
0.30
-
0.05
0.37
12.00 BSC
0.60
10.00 BSC
10.00 BSC
-
-
12.00 BSC
MILLIMETERS
MIN NOM
44
0.75
0.45
1.20
0.15
MAX
0.95 1.00 1.05
REF: Reference Dimension, usually without tolerance, for information purposes only.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
1.
2.
3.
No te s :
Pin 1 visual index feature may vary, but must be located within the hatched area.
Exact shape of each corner is optional.
Dimensioning and tolerancing per ASME Y14.5M
Footprint L1 1.00 REF
θ3.5° Foot Angle
Lead Thickness c0.09 - 0.20
44-Lead Plastic Thin Quad Flatpack (PT) - 10x10x1.0 mm Body [TQFP]
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 822
RECOMMENDED LAND PATTERN
44-Lead Plastic Thin Quad Flatpack (PT) - 10X10X1 mm Body, 2.00 mm Footprint [TQFP]
SILK SCREEN
1
2
44
C1
E
G
Y1
X1
C2
Contact Pad Width (X44)
0.25
Contact Pad Length (X44)
Distance Between Pads
X1
Y1
G
1.50
Contact Pad Spacing
Contact Pitch
C1
E
Units
Dimension Limits
11.40
0.55
0.80 BSC
MILLIMETERS
MAX
MIN NOM
11.40C2Contact Pad Spacing
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
1. Dimensioning and tolerancing per ASME Y14.5M
Notes:
Microchip Technology Drawing No. C04-2076B
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Note:
PIC18F26/45/46Q10
Packaging Information
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 823
42. Revision History
Doc Rev. Date Comments
C 5/2019 Removed 44-pin QFN packages
Corrected Tables 1, 2, 39-3, 39-5, 39-6, 39-8, 39-13, 39-15, and 39-18; Corrected
Figures 39-9 and 39-10
B 11/2018 Corrected capitalization and hyphens.
Changes to:
Sections 14.12.7, 22.3.2 (note), 22.6.1(note), 24.11.1, 25.11.1.3, 26, 26.4.5(note1),
33.1.2(note)
Figures 1, 25-3 through 25-11, 25-14, 25-15
Tables 2, 39-4, 39-6
Trademarks
A 03/2018 Initial document release.
PIC18F26/45/46Q10
Revision History
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 824
The Microchip Web Site
Microchip provides online support via our web site at http://www.microchip.com/. This web site is used as
a means to make files and information easily available to customers. Accessible by using your favorite
Internet browser, the web site contains the following information:
Product Support – Data sheets and errata, application notes and sample programs, design
resources, user’s guides and hardware support documents, latest software releases and archived
software
General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online
discussion groups, Microchip consultant program member listing
Business of Microchip – Product selector and ordering guides, latest Microchip press releases,
listing of seminars and events, listings of Microchip sales offices, distributors and factory
representatives
Customer Change Notification Service
Microchip’s customer notification service helps keep customers current on Microchip products.
Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata
related to a specified product family or development tool of interest.
To register, access the Microchip web site at http://www.microchip.com/. Under “Support”, click on
“Customer Change Notification” and follow the registration instructions.
Customer Support
Users of Microchip products can receive assistance through several channels:
Distributor or Representative
Local Sales Office
Field Application Engineer (FAE)
Technical Support
Customers should contact their distributor, representative or Field Application Engineer (FAE) for support.
Local sales offices are also available to help customers. A listing of sales offices and locations is included
in the back of this document.
Technical support is available through the web site at: http://www.microchip.com/support
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 825
Product Identification System
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO. –X /XX
Package
[X](1)
Tape
and Reel
Device Temperature
Range
Device: PIC18F26Q10, PIC18F45Q10, PIC18F46Q10
Tape & Reel Option: Blank = Tube
T = Tape & Reel
Temperature Range: I = -40°C to +85°C (Industrial)
E = -40°C to +125°C (Extended)
Package: STX = 28-lead VQFN 4x4x1 mm
ML = 28-lead QFN 6x6x0.9 mm
SO = 28-lead SOIC
SP = 28-lead Skinny Plastic DIP
SS = 28-lead SSOP
P = 40-lead PDIP
MP = 40-lead QFN 5x5x0.9 mm
PT = 44-lead TQFP
Examples:
PIC18F26Q10-E/P 301: Extended temp., PDIP package, QTP pattern #301.
PIC18F45Q10-E/PT = Extended temp., TQFP package.
PIC18F46Q10T-I/MP = Tape and reel, Industrial temp., QFN package.
Note: 
1. Tape and Reel identifier only appears in the catalog part number description. This identifier is used
for ordering purposes and is not printed on the device package. Check with your Microchip Sales
Office for package availability with the Tape and Reel option.
2. Small form-factor packaging options may be available. Please check http://www.microchip.com/
packaging for small-form factor package availability, or contact your local Sales Office.
Microchip Devices Code Protection Feature
Note the following details of the code protection feature on Microchip devices:
Microchip products meet the specification contained in their particular Microchip Data Sheet.
Microchip believes that its family of products is one of the most secure families of its kind on the
market today, when used in the intended manner and under normal conditions.
There are dishonest and possibly illegal methods used to breach the code protection feature. All of
these methods, to our knowledge, require using the Microchip products in a manner outside the
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 826
operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is
engaged in theft of intellectual property.
Microchip is willing to work with the customer who is concerned about the integrity of their code.
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their
code. Code protection does not mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the
code protection features of our products. Attempts to break Microchip’s code protection feature may be a
violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software
or other copyrighted work, you may have a right to sue for relief under that Act.
Legal Notice
Information contained in this publication regarding device applications and the like is provided only for
your convenience and may be superseded by updates. It is your responsibility to ensure that your
application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY
OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS
CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE.
Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life
support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend,
indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting
from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual
property rights unless otherwise stated.
Trademarks
The Microchip name and logo, the Microchip logo, AnyRate, AVR, AVR logo, AVR Freaks, BitCloud,
chipKIT, chipKIT logo, CryptoMemory, CryptoRF, dsPIC, FlashFlex, flexPWR, Heldo, JukeBlox, KeeLoq,
Kleer, LANCheck, LINK MD, maXStylus, maXTouch, MediaLB, megaAVR, MOST, MOST logo, MPLAB,
OptoLyzer, PIC, picoPower, PICSTART, PIC32 logo, Prochip Designer, QTouch, SAM-BA, SpyNIC, SST,
SST Logo, SuperFlash, tinyAVR, UNI/O, and XMEGA are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
ClockWorks, The Embedded Control Solutions Company, EtherSynch, Hyper Speed Control, HyperLight
Load, IntelliMOS, mTouch, Precision Edge, and Quiet-Wire are registered trademarks of Microchip
Technology Incorporated in the U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any Capacitor, AnyIn, AnyOut, BodyCom,
CodeGuard, CryptoAuthentication, CryptoAutomotive, CryptoCompanion, CryptoController, dsPICDEM,
dsPICDEM.net, Dynamic Average Matching, DAM, ECAN, EtherGREEN, In-Circuit Serial Programming,
ICSP, INICnet, Inter-Chip Connectivity, JitterBlocker, KleerNet, KleerNet logo, memBrain, Mindi, MiWi,
motorBench, MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient
Code Generation, PICDEM, PICDEM.net, PICkit, PICtail, PowerSmart, PureSilicon, QMatrix, REAL ICE,
Ripple Blocker, SAM-ICE, Serial Quad I/O, SMART-I.S., SQI, SuperSwitcher, SuperSwitcher II, Total
Endurance, TSHARC, USBCheck, VariSense, ViewSpan, WiperLock, Wireless DNA, and ZENA are
trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated in the U.S.A.
Silicon Storage Technology is a registered trademark of Microchip Technology Inc. in other countries.
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 827
GestIC is a registered trademark of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of
Microchip Technology Inc., in other countries.
All other trademarks mentioned herein are property of their respective companies.
© 2019, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved.
ISBN: 978-1-5224-4460-2
Quality Management System Certified by DNV
ISO/TS 16949
Microchip received ISO/TS-16949:2009 certification for its worldwide headquarters, design and wafer
fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC®
DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design and manufacture of development
systems is ISO 9001:2000 certified.
PIC18F26/45/46Q10
© 2019 Microchip Technology Inc. Datasheet Preliminary DS40001996C-page 828
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