© 2009 Microchip Technology Inc. DS39689F
PIC18F2221/2321/4221/4321
Family Data Sheet
Enhanced Flash Microcontrollers with
10-Bit A/D and nanoWatt Technology
DS39689F-page 2 © 2009 Microchip Technology Inc.
Information contained in this publication regarding device
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rfPIC and UNI/O are registered trademarks of Microchip
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© 2009, Microchip Technology Incorporated, Printed in the
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Printed on recycled paper.
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 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
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and India. The Company’s quality system processes and procedures
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and manufacture of development systems is ISO 9001:2000 certified.
© 2009 Microchip Technology Inc. DS39689F-page 3
PIC18F2221/2321/4221/4321 FAMILY
Power-Managed Modes:
Run: CPU On, Peripherals On
Idle: CPU Off, Peripherals On
Sleep: CPU Off, Peripherals Off
Idle mode Currents Down to 2.5 μA Typical
Sleep mode Currents Down to 500 nA Typical
Timer1 Oscillator: 1.8 μA, 32 kHz, 2V Typical
Watchdog Timer: 1.6 μA, 2V Typical
Two-Speed Oscillator Start-up
Flexible Oscillator Structure:
Four Crystal modes, up to 40 MHz
4x Phase Lock Loop (PLL) – Available for Crystal
and Internal Oscillators
Two External RC modes, up to 4 MHz
Two External Clock modes, up to 40 MHz
Internal Oscillator Block:
- 8 user-selectable frequencies, from 31 kHz to
8MHz
- Provides a complete range of clock speeds
from 31 kHz to 32 MHz when used with PLL
- User-tunable to compensate for frequency drift
Secondary Oscillator using Timer1 @ 32 kHz
Fail-Safe Clock Monitor
- Allows for safe shutdown if peripheral clock stops
Peripheral Highlights:
High-Current Sink/Source 25 mA/25 mA
Three Programmable External Interrupts
Four Input Change Interrupts
Up to 2 Capture/Compare/PWM (CCP) modules,
one with Auto-Shutdown (28-pin devices)
Enhanced Capture/Compare/PWM (ECCP)
module (40/44-pin devices only):
- One, two or four PWM outputs
- Selectable polarity
- Programmable dead time
- Auto-shutdown and auto-restart
Peripheral Highlights (Continued):
Master Synchronous Serial Port (MSSP) module
Supporting 3-Wire SPI (all 4 modes) and I2C™
Master and Slave modes
Enhanced Addressable USART module:
- Supports RS-485, RS-232 and LIN/J2602
- Auto-wake-up on Start bit
- Auto-Baud Detect
10-Bit, up to 13-Channel Analog-to-Digital
Converter module (A/D):
- Auto-acquisition capability
- Conversion available during Sleep
Dual Analog Comparators with Input Multiplexing
Programmable 16-Level High/Low-Voltage
Detection (HLVD) module:
- Supports interrupt on High/Low-Voltage Detection
Special Microcontroller Features:
C Compiler Optimized Architecture:
- Optional extended instruction set designed to
optimize re-entrant code
100,000 Erase/Write Cycle Enhanced Flash
Program Memory Typical
1,000,000 Erase/Write Cycle Data EEPROM
Memory Typical
Flash/Data EEPROM Retention: 100 Years Typical
Self-Programmable under Software Control
Priority Levels for Interrupts
8 x 8 Single-Cycle Hardware Multiplier
Extended Watchdog Timer (WDT):
- Programmable period from 4 ms to 131s
Single-Supply 5V In-Circuit Serial
Programming™ (ICSP™) via Two Pins
In-Circuit Debug (ICD) via Two Pins
Wide Operating Voltage Range: 2.0V to 5.5V
Programmable Brown-out Reset (BOR) with
Software Enable Option)
-
Device
Program Memory Data Memory
I/O 10-Bit
A/D (ch)
CCP/
ECCP
(PWM)
MSSP
EUSART
Comp. Timers
8/16-Bit
Flash
(bytes)
# Single-Word
Instructions
SRAM
(bytes)
EEPROM
(bytes) SPI Master
I2C™
PIC18F2221 4K 2048 512 256 25 10 2/0 Y Y 1 2 1/3
PIC18F2321 8K 4096 512 256 25 10 2/0 Y Y 1 2 1/3
PIC18F4221 4K 2048 512 256 36 13 1/1 Y Y 1 2 1/3
PIC18F4321 8K 4096 512 256 36 13 1/1 Y Y 1 2 1/3
28/40/44-Pin Enhanced Flash Microcontrollers with
10-Bit A/D and nanoWatt Technology
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 4 © 2009 Microchip Technology Inc.
Pin Diagrams
PIC18F2321
10
11
2
3
4
5
6
1
8
7
9
12
13
14 15
16
17
18
19
20
23
24
25
26
27
28
22
21
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
VSS
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RB7/KBI3/PGD
RB6//KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2
RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
28-Pin SPDIP, SOIC, SSOP
PIC18F2221
28-Pin QFN
10 11
2
3
6
1
18
19
20
21
22
12 13 14 15
8
7
16
17
232425262728
9
PIC18F2221
RC0/T1OSO/T13CKI
5
4
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2(1)
RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
VSS
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC1/T1OSI/CCP2(1)
RC2/CCP1
RC3/SCK/SCL
Note 1: RB3 is the alternate pin for CCP2 multiplexing.
PIC18F2321
© 2009 Microchip Technology Inc. DS39689F-page 5
PIC18F2221/2321/4221/4321 FAMILY
Pin Diagrams (Continued)
10
11
2
3
4
5
6
1
18
19
20
21
22
12
13
14
15
38
8
7
44
43
42
41
40
39
16
17
29
30
31
32
33
23
24
25
26
27
28
36
34
35
9
PIC18F4221
37
RA3/AN3/VREF+
RA2/AN2/VREF-/CVREF
RA1/AN1
RA0/AN0
MCLR/VPP/RE3
RB3/AN9/CCP2(1)
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
NC
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1/P1A
RC1/T1OSI/CCP2(1)
RC0/T1OSO/T13CKI
OSC2/CLKO/RA6
OSC1/CLKI/RA7
VSS
VSS
VDD
VDD
RE2/CS/AN7
RE1/WR/AN6
RE0/RD/AN5
RA5/AN4/SS/HLVDIN/C2OUT
RA4/T0CKI/C1OUT
RC7/RX/DT
RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D
VSS
VDD
VDD
RB0/INT0/FLT0/AN12
RB1/INT1/AN10
RB2/INT2/AN8
44-Pin QFN(2)
PIC18F4321
Note 1: RB3 is the alternate pin for CCP2 multiplexing.
2: For the QFN package, it is recommended that the bottom pad be connected to VSS.
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2
RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
VDD
VSS
RD7/PSP7/P1D
RD6/PSP6/P1C
RD5/PSP5/P1B
RD4/PSP4
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2
RC2/CCP1/P1A
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
PIC18F4321
40-Pin PDIP
PIC18F4221
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 6 © 2009 Microchip Technology Inc.
Pin Diagrams (Continued)
10
11
2
3
4
5
6
1
18
19
20
21
22
12
13
14
15
38
8
7
44
43
42
41
40
39
16
17
29
30
31
32
33
23
24
25
26
27
28
36
34
35
9
PIC18F4221
37
RA3/AN3/VREF+
RA2/AN2/VREF-/CVREF
RA1/AN1
RA0/AN0
MCLR/VPP/RE3
NC
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
NC
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1/P1A
RC1/T1OSI/CCP2(1)
NC
NC
RC0/T1OSO/T13CKI
OSC2/CLKO/RA6
OSC1/CLKI/RA7
VSS
VDD
RE2/CS/AN7
RE1/WR/AN6
RE0/RD/AN5
RA5/AN4/SS/HLVDIN/C2OUT
RA4/T0CKI/C1OUT
RC7/RX/DT
RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D
VSS
VDD
RB0/INT0/FLT0/AN12
RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2(1)
44-Pin TQFP
PIC18F4321
Note 1: RB3 is the alternate pin for CCP2 multiplexing.
© 2009 Microchip Technology Inc. DS39689F-page 7
PIC18F2221/2321/4221/4321 FAMILY
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 9
2.0 Guidelines for Getting Started with PIC18F Microcontrollers ..................................................................................................... 25
3.0 Oscillator Configurations ............................................................................................................................................................ 29
4.0 Power-Managed Modes ............................................................................................................................................................. 39
5.0 Reset .......................................................................................................................................................................................... 47
6.0 Memory Organization ................................................................................................................................................................. 59
7.0 Flash Program Memory.............................................................................................................................................................. 79
8.0 Data EEPROM Memory ............................................................................................................................................................. 89
9.0 8 x 8 Hardware Multiplier............................................................................................................................................................ 95
10.0 Interrupts .................................................................................................................................................................................... 97
11.0 I/O Ports ................................................................................................................................................................................... 111
12.0 Timer0 Module ......................................................................................................................................................................... 129
13.0 Timer1 Module ......................................................................................................................................................................... 133
14.0 Timer2 Module ......................................................................................................................................................................... 139
15.0 Timer3 Module ......................................................................................................................................................................... 141
16.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 145
17.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................ 153
18.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 167
19.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 211
20.0 10-Bit Analog-to-Digital Converter (A/D) Module ..................................................................................................................... 233
21.0 Comparator Module.................................................................................................................................................................. 243
22.0 Comparator Voltage Reference Module................................................................................................................................... 249
23.0 High/Low-Voltage Detect (HLVD)............................................................................................................................................. 253
24.0 Special Features of the CPU.................................................................................................................................................... 259
25.0 Instruction Set Summary .......................................................................................................................................................... 279
26.0 Development Support............................................................................................................................................................... 329
27.0 Electrical Characteristics.......................................................................................................................................................... 333
28.0 Packaging Information.............................................................................................................................................................. 373
Appendix A: Revision History............................................................................................................................................................. 385
Appendix B: Device Differences ........................................................................................................................................................ 386
Appendix C: Conversion Considerations ........................................................................................................................................... 387
Appendix D: Migration from Baseline to Enhanced Devices.............................................................................................................. 387
Appendix E: Migration From Mid-Range to Enhanced Devices ......................................................................................................... 388
Appendix F: Migration From High-End to Enhanced Devices............................................................................................................ 388
Index ................................................................................................................................................................................................. 389
The Microchip Web Site..................................................................................................................................................................... 399
Customer Change Notification Service .............................................................................................................................................. 399
Customer Support .............................................................................................................................................................................. 399
Reader Response .............................................................................................................................................................................. 400
PIC18F2221/2321/4221/4321 Product Identification System ............................................................................................................ 401
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 8 © 2009 Microchip Technology Inc.
TO OUR VALUED CUSTOMERS
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© 2009 Microchip Technology Inc. DS39689F-page 9
PIC18F2221/2321/4221/4321 FAMILY
1.0 DEVICE OVERVIEW
This document contains device specific information for
the following devices:
This family offers the advantages of all PIC18 micro-
controllers – namely, high computational performance at
an economical price – with the addition of high-
endurance, Enhanced Flash program memory. On top of
these features, the PIC18F2221/2321/4221/4321 family
introduces design enhancements that make these micro-
controllers a logical choice for many high-performance,
power sensitive applications.
1.1 New Core Features
1.1.1 nanoWatt TECHNOLOGY
All of the devices in the PIC18F2221/2321/4221/4321
family incorporate a range of features that can signifi-
cantly reduce power consumption during operation.
Key items include:
Alternate Run Modes: By clocking the controller
from the Timer1 source 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 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.
Low Consumption in Key Modules: The
power requirements for both Timer1 and the
Watchdog Timer are minimized. See
Section 27.0 “Electrical Characteristics” for
values.
1.1.2 MULTIPLE OSCILLATOR OPTIONS
AND FEATURES
All of the devices in the PIC18F2221/2321/4221/4321
family offer ten different oscillator options, allowing
users a wide range of choices in developing application
hardware. These include:
Four Crystal modes, using crystals or ceramic
resonators.
Two External Clock modes, offering the option of
using two pins (oscillator input and a divide-by-4
clock output) or one pin (oscillator input, with the
second pin reassigned as general I/O).
Two External RC Oscillator modes with the same
pin options as the External Clock modes.
Two Internal Oscillator modes which provide
an 8 MHz clock and an INTRC source
(approximately 31 kHz), as well as a range of
6 user-selectable clock frequencies, between
125 kHz to 4 MHz, for a total of 8 clock frequencies.
One or both of the oscillator pins can be used for
general purpose I/O.
A Phase Lock Loop (PLL) frequency multiplier,
available to both the high-speed crystal and
internal oscillator modes, which allows clock
speeds of up to 40 MHz. Used with the internal
oscillator, the PLL gives users a complete selection
of clock speeds, from 31 kHz to 32 MHz – all
without using an external crystal or clock circuit.
Besides its availability as a clock source, the internal
oscillator block provides a stable reference source that
gives the family additional features for robust
operation:
Fail-Safe Clock Monitor: This option constantly
monitors the main clock source against a reference
signal provided by the internal oscillator. If a clock
failure occurs, the controller is switched to the
internal oscillator block, allowing for continued
low-speed operation or a safe application
shutdown.
Two-Speed Start-up: This option allows the
internal oscillator to serve as the clock source
from Power-on Reset, or wake-up from Sleep
mode, until the primary clock source is available.
PIC18F2221 PIC18LF2221
PIC18F2321 PIC18LF2321
PIC18F4221 PIC18LF4221
PIC18F4321 PIC18LF4321
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 10 © 2009 Microchip Technology Inc.
1.2 Other Special Features
Memory Endurance: The Enhanced Flash cells
for both program memory and data EEPROM are
rated to last for many thousands of erase/write
cycles – up to 100,000 for program memory and
1,000,000 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 bootloader 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 PIC18F2221/
2321/4221/4321 family introduces an optional
extension to the PIC18 instruction set, which adds
8 new instructions and an Indexed Addressing
mode. This extension, enabled as a device con-
figuration option, has been specifically designed
to optimize re-entrant application code originally
developed in high-level languages, such as C.
Enhanced CCP Module: In PWM mode, this
module provides 1, 2 or 4 modulated outputs for
controlling half-bridge and full-bridge drivers.
Other features include auto-shutdown, for
disabling PWM outputs on interrupt or other select
conditions and auto-restart, to reactivate outputs
once the condition has cleared.
Enhanced Addressable USART: This serial
communication module is capable of standard
RS-232 operation and provides support for the
LIN/J2602 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: 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, reducing code overhead.
Extended Watchdog Timer (WDT): This
Enhanced version incorporates a 16-bit prescaler,
allowing an extended time-out range that is stable
across operating voltage and temperature. See
Section 27.0 “Electrical Characteristics” for
time-out periods.
1.3 Details on Individual Family
Members
Devices in the PIC18F2221/2321/4221/4321 family are
available in 28-pin and 40/44-pin packages. Block
diagrams for the two groups are shown in Figure 1-1 and
Figure 1-2.
The devices are differentiated from each other in five
ways:
1. Flash program memory (4 Kbytes for
PIC18F2221/4221 devices, 8 Kbytes for
PIC18F2321/4321).
2. A/D channels (10 for 28-pin devices, 13 for
40/44-pin devices).
3. I/O ports (3 bidirectional ports on 28-pin devices,
5 bidirectional ports on 40/44-pin devices).
4. CCP and Enhanced CCP implementation
(28-pin devices have 2 standard CCP
modules, 40/44-pin devices have one standard
CCP module and one ECCP module).
5. Parallel Slave Port (present only on 40/44-pin
devices).
All other features for devices in this family are identical.
These are summarized in Table 1-1.
The pinouts for all devices are listed in Table 1-2 and
Table 1-3.
Like all Microchip PIC18 devices, members of the
PIC18F2221/2321/4221/4321 family are available as
both standard and low-voltage devices. Standard
devices with Enhanced Flash memory, designated with
an “F” in the part number (such as PIC18F2321),
accommodate an operating VDD range of 4.2V to 5.5V.
Low-voltage parts, designated by “LF” (such as
PIC18LF2321), function over an extended VDD range
of 2.0V to 5.5V.
© 2009 Microchip Technology Inc. DS39689F-page 11
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-1: DEVICE FEATURES
Features PIC18F2221 PIC18F2321 PIC18F4221 PIC18F4321
Operating Frequency DC – 40 MHz DC – 40 MHz DC – 40 MHz DC – 40 MHz
Program Memory (Bytes) 4096 8192 4096 8192
Program Memory (Instructions) 2048 4096 2048 4096
Data Memory (Bytes) 512 512 512 512
Data EEPROM Memory (Bytes) 256 256 256 256
Interrupt Sources 19 19 20 20
I/O Ports Ports A, B, C, (E) Ports A, B, C, (E) Ports A, B, C, D, E Ports A, B, C, D, E
Timers 4 4 4 4
Capture/Compare/PWM Modules 2 2 1 1
Enhanced Capture/Compare/
PWM Modules
0011
Serial Communications MSSP,
Enhanced USART
MSSP,
Enhanced USART
MSSP,
Enhanced USART
MSSP,
Enhanced USART
Parallel Communications (PSP) No No Yes Yes
10-bit Analog-to-Digital Module 10 Input Channels 10 Input Channels 13 Input Channels 13 Input Channels
Resets (and Delays) POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST),
MCLR (optional),
WDT
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST),
MCLR (optional),
WDT
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST),
MCLR (optional),
WDT
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST),
MCLR (optional),
WDT
Programmable Low-Voltage
Detect
Yes Yes Yes Yes
Programmable Brown-out Reset Yes Yes Yes Yes
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
75 Instructions;
83 with Extended
Instruction Set
enabled
Packages 28-pin SPDIP
28-pin SOIC
28-pin SSOP
28-pin QFN
28-pin SPDIP
28-pin SOIC
28-pin SSOP
28-pin QFN
40-pin PDIP
44-pin QFN
44-pin TQFP
40-pin PDIP
44-pin QFN
44-pin TQFP
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 12 © 2009 Microchip Technology Inc.
FIGURE 1-1: PIC18F2221/2321 (28-PIN) BLOCK DIAGRAM
Instruction
Decode &
Control
PORTA
PORTB
PORTC
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
RB0/INT0/FLT0/AN12
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
RA3/AN3/VREF+
RA2/AN2/VREF-/CVREF
RA1/AN1
RA0/AN0
RB1/INT1/AN10
Data Latch
Data Memory
(3.9 Kbytes)
Address Latch
Data Address<12>
12
Access
BSR FSR0
FSR1
FSR2
inc/dec
logic
Address
412 4
PCH PCL
PCLATH
8
31 Level Stack
Program Counter
PRODLPRODH
8 x 8 Multiply
8
BITOP
8
8
ALU<8>
Address Latch
Program Memory
(4 Kbytes)
Data Latch
20
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
IR
12
3
ROM Latch
RB2/INT2/AN8
RB3/AN9/CCP2(1)
PCLATU
PCU
OSC2/CLKO(3)/RA6
Note 1: CCP2 is multiplexed with RC1 when Configuration bit, CCP2MX, is set, or RB3 when CCP2MX is not set.
2: RE3 is only available when MCLR functionality is disabled.
3: OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.
Refer to Section 3.0 “Oscillator Configurations” for additional information.
RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
EUSARTComparator MSSP 10-Bit
ADC
Timer2Timer1 Timer3Timer0
CCP2
LVD
CCP1
BOR Data
EEPROM
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(3)
OSC2(3)
VDD,
Brown-out
Reset
Internal
Oscillator
Fail-Safe
Clock Monitor
Precision
Reference
Band Gap
VSS
MCLR(2)
Block
INTRC
Oscillator
8 MHz
Oscillator
Single-Supply
Programming
In-Circuit
Debugger
T1OSO
OSC1/CLKI(3)/RA7
T1OSI
PORTE
MCLR/VPP/RE3(2)
© 2009 Microchip Technology Inc. DS39689F-page 13
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 1-2: PIC18F4221/4321 (40/44-PIN) BLOCK DIAGRAM
Instruction
Decode &
Control
Data Latch
Data Memory
(3.9 Kbytes)
Address Latch
Data Address<12>
12
Access
BSR FSR0
FSR1
FSR2
inc/dec
logic
Address
412 4
PCH PCL
PCLATH
8
31 Level Stack
Program Counter
PRODLPRODH
8 x 8 Multiply
8
BITOP
8
8
ALU<8>
Address Latch
Program Memory
(8 Kbytes)
Data Latch
20
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
IR
12
3
ROM Latch
PORTD
RD0/PSP0
PCLATU
PCU
PORTE
MCLR/VPP/RE3(2)
RE2/CS/AN7
RE0/RD/AN5
RE1/WR/AN6
Note 1: CCP2 is multiplexed with RC1 when Configuration bit, CCP2MX, is set, or RB3 when CCP2MX is not set.
2: RE3 is only available when MCLR functionality is disabled.
3: OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.
Refer to Section 3.0 “Oscillator Configurations” for additional information.
:RD4/PSP4
EUSARTComparator MSSP 10-Bit
ADC
Timer2Timer1 Timer3Timer0
CCP2
LVD
ECCP1
BOR Data
EEPROM
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(3)
OSC2(3)
VDD,
Brown-out
Reset
Internal
Oscillator
Fail-Safe
Clock Monitor
Precision
Reference
Band Gap
VSS
MCLR(2)
Block
INTRC
Oscillator
8 MHz
Oscillator
Single-Supply
Programming
In-Circuit
Debugger
T1OSI
T1OSO
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D
PORTA
PORTB
PORTC
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
RB0/INT0/FLT0/AN12
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1/P1A
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
RA3/AN3/VREF+
RA2/AN2/VREF-/CVREF
RA1/AN1
RA0/AN0
RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2(1)
OSC2/CLKO(3)/RA6
RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
OSC1/CLKI(3)/RA7
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 14 © 2009 Microchip Technology Inc.
TABLE 1-2: PIC18F2221/2321 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type Description
SPDIP,
SOIC,
SSOP
QFN
MCLR/VPP/RE3
MCLR
VPP
RE3
126
I
P
I
ST
ST
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage input.
Digital input.
OSC1/CLKI/RA7
OSC1
CLKI
RA7
96
I
I
I/O
Analog
CMOS
TTL
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode; CMOS otherwise.
External clock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
General purpose I/O pin.
OSC2/CLKO/RA6
OSC2
CLKO
RA6
10 7
O
O
I/O
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC, EC and INTIO modes, OSC2 pin outputs CLKO
which has one-fourth the frequency of OSC1 and denotes
the instruction cycle rate.
General purpose I/O pin.
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc. DS39689F-page 15
PIC18F2221/2321/4221/4321 FAMILY
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
227
I/O
I
TTL
Analog
Digital I/O.
Analog Input 0.
RA1/AN1
RA1
AN1
328
I/O
I
TTL
Analog
Digital I/O.
Analog Input 1.
RA2/AN2/VREF-/CVREF
RA2
AN2
VREF-
CVREF
41
I/O
I
I
O
TTL
Analog
Analog
Analog
Digital I/O.
Analog Input 2.
A/D reference voltage (low) input.
Comparator reference voltage output.
RA3/AN3/VREF+
RA3
AN3
VREF+
52
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog Input 3.
A/D reference voltage (high) input.
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
63
I/O
I
O
ST
ST
Digital I/O. Open-collector output.
Timer0 external clock input.
Comparator 1 output.
RA5/AN4/SS/HLVDIN/
C2OUT
RA5
AN4
SS
HLVDIN
C2OUT
74
I/O
I
I
I
O
TTL
Analog
TTL
Analog
Digital I/O.
Analog Input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.
RA6 See the OSC2/CLKO/RA6 pin.
RA7 See the OSC1/CLKI/RA7 pin.
TABLE 1-2: PIC18F2221/2321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
Pin
Type
Buffer
Type Description
SPDIP,
SOIC,
SSOP
QFN
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 16 © 2009 Microchip Technology Inc.
PORTB is a bidirectional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.
RB0/INT0/FLT0/AN12
RB0
INT0
FLT0
AN12
21 18
I/O
I
I
I
TTL
ST
ST
Analog
Digital I/O.
External Interrupt 0.
PWM Fault input for CCP1.
Analog Input 12.
RB1/INT1/AN10
RB1
INT1
AN10
22 19
I/O
I
I
TTL
ST
Analog
Digital I/O.
External Interrupt 1.
Analog Input 10.
RB2/INT2/AN8
RB2
INT2
AN8
23 20
I/O
I
I
TTL
ST
Analog
Digital I/O.
External Interrupt 2.
Analog Input 8.
RB3/AN9/CCP2
RB3
AN9
CCP2(2)
24 21
I/O
I
I/O
TTL
Analog
ST
Digital I/O.
Analog Input 9.
Capture 2 input/Compare 2 output/PWM2 output.
RB4/KBI0/AN11
RB4
KBI0
AN11
25 22
I/O
I
I
TTL
TTL
Analog
Digital I/O.
Interrupt-on-change pin.
Analog Input 11.
RB5/KBI1/PGM
RB5
KBI1
PGM
26 23
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP™ programming enable pin.
RB6/KBI2/PGC
RB6
KBI2
PGC
27 24
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming clock pin.
RB7/KBI3/PGD
RB7
KBI3
PGD
28 25
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming data pin.
TABLE 1-2: PIC18F2221/2321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
Pin
Type
Buffer
Type Description
SPDIP,
SOIC,
SSOP
QFN
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc. DS39689F-page 17
PIC18F2221/2321/4221/4321 FAMILY
PORTC is a bidirectional I/O port.
RC0/T1OSO/T13CKI
RC0
T1OSO
T13CKI
11 8
I/O
O
I
ST
ST
Digital I/O.
Timer1 oscillator analog output.
Timer1/Timer3 external clock input.
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2(1)
12 9
I/O
I
I/O
ST
Analog
ST
Digital I/O.
Timer1 oscillator analog input.
Capture 2 input/Compare 2 output/PWM2 output.
RC2/CCP1
RC2
CCP1
13 10
I/O
I/O
ST
ST
Digital I/O.
Capture 1 input/Compare 1 output/PWM1 output.
RC3/SCK/SCL
RC3
SCK
SCL
14 11
I/O
I/O
I/O
ST
ST
I2C
Digital I/O.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C™ mode.
RC4/SDI/SDA
RC4
SDI
SDA
15 12
I/O
I
I/O
ST
ST
I2C
Digital I/O.
SPI data in.
I2C data I/O.
RC5/SDO
RC5
SDO
16 13
I/O
O
ST
Digital I/O.
SPI data out.
RC6/TX/CK
RC6
TX
CK
17 14
I/O
O
I/O
ST
ST
Digital I/O.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).
RC7/RX/DT
RC7
RX
DT
18 15
I/O
I
I/O
ST
ST
ST
Digital I/O.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).
RE3 See MCLR/VPP/RE3 pin.
VSS 8, 19 5, 16 P Ground reference for logic and I/O pins.
VDD 20 17 P Positive supply for logic and I/O pins.
TABLE 1-2: PIC18F2221/2321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
Pin
Type
Buffer
Type Description
SPDIP,
SOIC,
SSOP
QFN
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 18 © 2009 Microchip Technology Inc.
TABLE 1-3: PIC18F4221/4321 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number Pin
Type
Buffer
Type Description
PDIP QFN TQFP
MCLR/VPP/RE3
MCLR
VPP
RE3
11818
I
P
I
ST
ST
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage input.
Digital input.
OSC1/CLKI/RA7
OSC1
CLKI
RA7
13 32 30
I
I
I/O
Analog
Analog
TTL
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode;
analog otherwise.
External clock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
General purpose I/O pin.
OSC2/CLKO/RA6
OSC2
CLKO
RA6
14 33 31
O
O
I/O
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal
or resonator in Crystal Oscillator mode.
In RC, EC and INTIO modes, OSC2 pin outputs
CLKO which has one-fourth the frequency of OSC1
and denotes the instruction cycle rate.
General purpose I/O pin.
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc. DS39689F-page 19
PIC18F2221/2321/4221/4321 FAMILY
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
21919
I/O
I
TTL
Analog
Digital I/O.
Analog Input 0.
RA1/AN1
RA1
AN1
32020
I/O
I
TTL
Analog
Digital I/O.
Analog Input 1.
RA2/AN2/VREF-/CVREF
RA2
AN2
VREF-
CVREF
42121
I/O
I
I
O
TTL
Analog
Analog
Analog
Digital I/O.
Analog Input 2.
A/D reference voltage (low) input.
Comparator reference voltage output.
RA3/AN3/VREF+
RA3
AN3
VREF+
52222
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog Input 3.
A/D reference voltage (high) input.
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
62323
I/O
I
O
ST
ST
Digital I/O.
Timer0 external clock input.
Comparator 1 output.
RA5/AN4/SS/HLVDIN/
C2OUT
RA5
AN4
SS
HLVDIN
C2OUT
72424
I/O
I
I
I
O
TTL
Analog
TTL
Analog
Digital I/O.
Analog Input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.
RA6 See the OSC2/CLKO/RA6 pin.
RA7 See the OSC1/CLKI/RA7 pin.
TABLE 1-3: PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
PDIP QFN TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 20 © 2009 Microchip Technology Inc.
PORTB is a bidirectional I/O port. PORTB can be
software programmed for internal weak pull-ups on all
inputs.
RB0/INT0/FLT0/AN12
RB0
INT0
FLT0
AN12
33 9 8
I/O
I
I
I
TTL
ST
ST
Analog
Digital I/O.
External Interrupt 0.
PWM Fault input for Enhanced CCP1.
Analog input 12.
RB1/INT1/AN10
RB1
INT1
AN10
34 10 9
I/O
I
I
TTL
ST
Analog
Digital I/O.
External Interrupt 1.
Analog Input 10.
RB2/INT2/AN8
RB2
INT2
AN8
35 11 10
I/O
I
I
TTL
ST
Analog
Digital I/O.
External Interrupt 2.
Analog Input 8.
RB3/AN9/CCP2
RB3
AN9
CCP2(2)
36 12 11
I/O
I
I/O
TTL
Analog
ST
Digital I/O.
Analog Input 9.
Capture 2 input/Compare 2 output/PWM2 output.
RB4/KBI0/AN11
RB4
KBI0
AN11
37 14 14
I/O
I
I
TTL
TTL
Analog
Digital I/O.
Interrupt-on-change pin.
Analog input 11.
RB5/KBI1/PGM
RB5
KBI1
PGM
38 15 15
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP™ Programming enable pin.
RB6/KBI2/PGC
RB6
KBI2
PGC
39 16 16
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming
clock pin.
RB7/KBI3/PGD
RB7
KBI3
PGD
40 17 17
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming
data pin.
TABLE 1-3: PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
PDIP QFN TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc. DS39689F-page 21
PIC18F2221/2321/4221/4321 FAMILY
PORTC is a bidirectional I/O port.
RC0/T1OSO/T13CKI
RC0
T1OSO
T13CKI
15 34 32
I/O
O
I
ST
ST
Digital I/O.
Timer1 oscillator analog output.
Timer1/Timer3 external clock input.
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2(1)
16 35 35
I/O
I
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator analog input.
Capture 2 input/Compare 2 output/PWM2 output.
RC2/CCP1/P1A
RC2
CCP1
P1A
17 36 36
I/O
I/O
O
ST
ST
Digital I/O.
Capture 1 input/Compare 1 output/PWM1 output.
Enhanced CCP1 output.
RC3/SCK/SCL
RC3
SCK
SCL
18 37 37
I/O
I/O
I/O
ST
ST
I2C
Digital I/O.
Synchronous serial clock input/output for
SPI mode.
Synchronous serial clock input/output for I2C™
mode.
RC4/SDI/SDA
RC4
SDI
SDA
23 42 42
I/O
I
I/O
ST
ST
I2C
Digital I/O.
SPI data in.
I2C data I/O.
RC5/SDO
RC5
SDO
24 43 43
I/O
O
ST
Digital I/O.
SPI data out.
RC6/TX/CK
RC6
TX
CK
25 44 44
I/O
O
I/O
ST
ST
Digital I/O.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).
RC7/RX/DT
RC7
RX
DT
26 1 1
I/O
I
I/O
ST
ST
ST
Digital I/O.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).
TABLE 1-3: PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
PDIP QFN TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 22 © 2009 Microchip Technology Inc.
PORTD is a bidirectional I/O port or a Parallel Slave
Port (PSP) for interfacing to a microprocessor port.
These pins have TTL input buffers when the PSP
module is enabled.
RD0/PSP0
RD0
PSP0
19 38 38
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
RD1/PSP1
RD1
PSP1
20 39 39
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
RD2/PSP2
RD2
PSP2
21 40 40
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
RD3/PSP3
RD3
PSP3
22 41 41
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
RD4/PSP4
RD4
PSP4
27 2 2
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
RD5/PSP5/P1B
RD5
PSP5
P1B
28 3 3
I/O
I/O
O
ST
TTL
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
RD6/PSP6/P1C
RD6
PSP6
P1C
29 4 4
I/O
I/O
O
ST
TTL
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
RD7/PSP7/P1D
RD7
PSP7
P1D
30 5 5
I/O
I/O
O
ST
TTL
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
TABLE 1-3: PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
PDIP QFN TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc. DS39689F-page 23
PIC18F2221/2321/4221/4321 FAMILY
PORTE is a bidirectional I/O port.
RE0/RD/AN5
RE0
RD
AN5
82525
I/O
I
I
ST
TTL
Analog
Digital I/O.
Read control for Parallel Slave Port
(see also WR and CS pins).
Analog Input 5.
RE1/WR/AN6
RE1
WR
AN6
92626
I/O
I
I
ST
TTL
Analog
Digital I/O.
Write control for Parallel Slave Port
(see CS and RD pins).
Analog Input 6.
RE2/CS/AN7
RE2
CS
AN7
10 27 27
I/O
I
I
ST
TTL
Analog
Digital I/O.
Chip Select control for Parallel Slave Port
(see related RD and WR).
Analog Input 7.
RE3 See MCLR/VPP/RE3 pin.
VSS 12, 31 6, 30,
31
6, 29 P Ground reference for logic and I/O pins.
VDD 11, 32 7, 8,
28, 29
7, 28 P Positive supply for logic and I/O pins.
NC 13 12, 13,
33, 34
No Connect.
TABLE 1-3: PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
PDIP QFN TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input P = Power
I2C = ST with I2C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 24 © 2009 Microchip Technology Inc.
NOTES:
© 2009 Microchip Technology Inc. DS39689F-page 25
PIC18F2221/2321/4221/4321 FAMILY
2.0 GUIDELINES FOR GETTING
STARTED WITH PIC18F
MICROCONTROLLERS
2.1 Basic Connection Requirements
Getting started with the PIC18F2221/2321/4221/4321
family 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 V
DD and VSS pins
(see Section 2.2 “Power Supply Pins”)
•All AV
DD and AVSS pins, regardless of whether or
not the analog device features are used
(see Section 2.2 “Power Supply Pins”)
•M
CLR pin
(see Section 2.3 “Master Clear (MCLR) Pin”)
These pins must also be connected if they are being
used in the end application:
PGC/PGD pins used for In-Circuit Serial
Programming™ (ICSP™) and debugging purposes
(see Section 2.4 “ICSP Pins”)
OSCI and OSCO pins when an external oscillator
source is used
(see Section 2.5 “External Oscillator Pins”)
Additionally, the following pins may be required:
•V
REF+/VREF- pins used when external voltage
reference for analog modules is implemented
The minimum mandatory connections are shown in
Figure 2-1.
FIGURE 2-1: RECOMMENDED
MINIMUM CONNECTIONS
Note: The AVDD and AVSS pins must always be
connected, regardless of whether any of
the analog modules are being used.
PIC18FXXXX
VDD
VSS
VDD
VSS
VSS
VDD
AVDD
AVSS
VDD
VSS
C1
R1
VDD
MCLR
R2
C2(1)
C3(1)
C4(1)
C5(1)
C6(1)
Key (all values are recommendations):
C1 through C6: 0.1 μF, 20V ceramic
C7: 10 μF, 16V tantalum or ceramic
R1: 10 k
R2: 100 to 470
Note 1: The example shown is for a PIC18F device
with five VDD/VSS and AVDD/AVSS pairs.
Other devices may have more or less pairs;
adjust the number of decoupling capacitors
appropriately.