1998 Microchip Technology Inc.
Preliminary
DS40143C-page 1
Devices included in this data sheet:
Referred to collectively as PIC16C55X.
• PIC16C554
• PIC16C558
High Performance RISC CPU:
• Only 35 instructions to learn
• All single-cycle instructions (200 ns), except for
program branches which are two-cycle
• Operating speed:
- DC - 20 MHz clock input
- DC - 200 ns instruction cycle
• Interrupt capability
• 16 special function hardware registers
• 8-level deep hardware stack
• Direct, Indirect and Relative addressing modes
Peripheral Features:
• 13 I/O pins with individual direction control
• High current sink/source for direct LED drive
• Timer0: 8-bit timer/counter with 8-bit
programmable prescaler
Special Microcontroller Features:
• Power-on Reset (POR)
• Power-up Timer (PWRT) and Oscillator Start-up
Timer (OST)
• Watchdog Timer (WDT) with its own on-chip RC
oscillator for reliable operation
Device Program
Memory Data
Memory
PIC16C554 512 80
PIC16C558 2K 128
Pin Diagram
Special Microcontroller Features (cont’d)
• Programmable code protection
• Power saving SLEEP mode
• Selectable oscillator options
• Serial in-circuit programming (via two pins)
• Four user programmable ID locations
CMOS Technology:
• Low-power, high-speed CMOS EPROM technology
• Fully static design
• Wide operating voltage range
- 2.5V to 5.5V
• Commercial, industrial and extended tempera-
ture range
• Low power consumption
- < 2.0 mA @ 5.0V, 4.0 MHz
- 15
µ
A typical @ 3.0V, 32 kHz
- < 1.0
µ
A typical standby current @ 3.0V
RA1
RA0
OSC2/CLKOUT
VDD
RB7
RB6
RB5
RB4
OSC1/CLKIN
RA2
RA3
MCLR/ VPP
VSS
RB0/INT
RB1
RB2
RB3
RA4/T0CKI
RA1
RA0
OSC2/CLKOUT
VDD
RB7
RB6
RB5
RB4
OSC1/CLKIN
RA2
RA3
MCLR/ VPP
VSS
VSS
RB0/INT
RB1
RB2
RA4/T0CKI
PIC16C55X
RB3RB3
VDD
PDIP, SOIC, Windowed CERDIP
SSOP
2
3
4
5
6
7
8
9
10
•1
2
3
4
5
6
7
8
9
•1
19
18
16
15
14
13
12
11
17
18
17
15
14
13
12
11
10
16
20
PIC16C55X
EPROM-Based 8-Bit CMOS Microcontrollers
PIC16C55X
PIC16C55X
DS40143C-page 2
Preliminary
1998 Microchip Technology Inc.
Device Differences
Note 1:
If you change from this device to another device, please verify oscillator characteristics in your application.
Device Voltage
Range Oscillator Process
Technology
(Microns)
PIC16C554 2.5 - 5.5 See Note 1 0.9
PIC16C558 2.5 - 5.5 See Note 1 0.9
1998 Microchip Technology Inc.
Preliminary
DS40143C-page 3
PIC16C55X
Table of Contents
1.0 General Description......................................................................................................................................................................5
2.0 PIC16C55X Device Varieties .......................................................................................................................................................7
3.0 Architectural Overview .................................................................................................................................................................9
4.0 Memory Organization................................................................................................................................................................ 13
5.0 I/O Ports.................................................................................................................................................................................... 23
6.0 Timer0 Module .......................................................................................................................................................................... 29
7.0 Special Features of the CPU..................................................................................................................................................... 35
8.0 Instruction Set Summary........................................................................................................................................................... 51
9.0 Development Support................................................................................................................................................................ 63
10.0 Electrical Specifications............................................................................................................................................................. 69
11.0 Packaging Information............................................................................................................................................................... 81
Appendix A: Enhancements............................................................................................................................................................ 87
Appendix B: Compatibility............................................................................................................................................................... 87
INDEX.................................................................................................................................................................................................. 89
PIC16C55X Product Identification System .......................................................................................................................................... 93
To Our Valued Customers
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please check our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number. e.g., DS30000A is version A of document DS30000.
Errata
An errata sheet may exist for current devices, describing minor operational differences (from the data sheet) and recommended
workarounds. As de vice/documentation issues become kno wn to us, we will pub lish an errata sheet. The errata will specify the revi-
sion of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
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When contacting a sales office or the literature center, please specify which device, revision of silicon and data sheet (include lit-
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Corrections to this Data Sheet
We constantly strive to improve the quality of all our products and documentation. We have spent a great deal of time to ensure
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We appreciate your assistance in making this a better document.
PIC16C55X
DS40143C-page 4
Preliminary
1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc.
Preliminary
DS40143C-page 5
PIC16C55X
1.0 GENERAL DESCRIPTION
The PIC16C55X are 18 and 20-Pin EPROM-based
members of the versatile PIC16CXX family of lo w-cost,
high-performance, CMOS, fully-static, 8-bit
microcontrollers.
All PICmicro
®
microcontrollers employ an advanced
RISC architecture. The PIC16C55X have enhanced
core features, eight-le vel deep stack, and multiple inter-
nal and external interrupt sources. The separate
instruction and data buses of the Harvard architecture
allow a 14-bit wide instruction word with the separate
8-bit wide data. The two-stage instruction pipeline
allows all instructions to execute in a single-cycle,
except for program branches (which require two
cycles). A total of 35 instructions (reduced instruction
set) are av ailable. Additionally, a large register set gives
some of the architectural innov ations used to achie v e a
very high performance.
PIC16C55X microcontrollers typically achieve a 2:1
code compression and a 4:1 speed improvement over
other 8-bit microcontrollers in their class.
The PIC16C554 has 80 bytes of RAM. The PIC16C558
has 128 bytes of RAM. Each de vice has 13 I/O pins and
an 8-bit timer/counter with an 8-bit programmab le pres-
caler.
PIC16C55X devices have special features to reduce
external components, thus reducing cost, enhancing
system reliability and reducing power consumption.
There are f our oscillator options, of which the single pin
RC oscillator provides a low-cost solution, the LP
oscillator minimizes power consumption, XT is a
standard crystal, and the HS is f or High Speed crystals.
The SLEEP (power-down) mode offers power saving.
The user can wake up the chip from SLEEP through
several external and internal interrupts and reset.
A highly reliable Watchdog Timer with its own on-chip
RC oscillator provides protection against software
lock-up.
A UV-erasable CERDIP-packaged version is ideal for
code development while the cost-effective One-Time
Programmable (OTP) version is suitable for production
in any volume.
Table 1-1 shows the features of the PIC16C55X
mid-range microcontroller families.
A simplified block diagram of the PIC16C55X is sho wn
in Figure 3-1.
The PIC16C55X series fit perfectly in applications
ranging from motor control to low-power remote sen-
sors. The EPROM technology makes customization of
application programs (detection levels, pulse genera-
tion, timers, etc.) extremely fast and convenient. The
small footprint packages make this microcontroller
series perfect f or all applications with space limitations .
Low-cost, low-power, high-performance, ease of use
and I/O flexibility make the PIC16C55X very versatile.
1.1 Family and Upward Compatibility
Those users familiar with the PIC16C5X family of
microcontrollers will realize that this is an enhanced
version of the PIC16C5X architecture. Please refer to
Appendix A for a detailed list of enhancements. Code
written for PIC16C5X can be easily ported to
PIC16C55X family of devices (Appendix B).
The PIC16C55X f amily fills the niche for users w anting
to migrate up from the PIC16C5X family and not need-
ing various peripheral f eatures of other members of the
PIC16XX mid-range microcontroller family.
1.2 Development Support
The PIC16C55X family is suppor ted by a full-featured
macro assembler, a software simulator, an in-circuit
emulator, a low-cost development programmer and a
full-featured programmer. A “C” compiler and fuzzy
logic support tools are also available.
PIC16C55X
DS40143C-page 6
Preliminary
1998 Microchip Technology Inc.
TABLE 1-1: PIC16C55X FAMILY OF DEVICES
PIC16C554 PIC16C558
Clock
Maximum Frequency of Operation (MHz) 20 20
Memory
EPROM Program Memory (x14 words) 512 2K
Data Memory (bytes) 80 128
Peripherals
Timer Module(s) TMR0 TMR0
Features
Interrupt Sources 3 3
I/O Pins 13 13
Voltage Range (Volts) 2.5-5.5 2.5-5.5
Brown-out Reset — —
Packages 18-pin DIP,
SOIC;
20-pin SSOP
18-pin DIP,
SOIC;
20-pin SSOP
All PICmicro
®
Family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high
I/O current capability. All PIC16C55X Family devices use serial programming with clock pin RB6 and data pin RB7.
1998 Microchip Technology Inc.
Preliminary
DS40143C-page 7
PIC16C55X
2.0 PIC16C55X DEVICE VARIETIES
A variety of frequency ranges and pac kaging options are
available. Depending on application and production
requirements the proper device option can be selected
using the information in the PIC16C55X Product
Identification System section at the end of this data
sheet. When placing orders, please use this page of the
data sheet to specify the correct part number.
2.1 UV Erasable Devices
The UV erasable version, offered in CERDIP package
is optimal for prototype development and pilot
programs. This version can be erased and
reprogrammed to any of the oscillator modes.
Microchip's PICSTART
and PROMATE
programmers both support programming of the
PIC16C55X.
2.2 One-Time-Programmable (OTP)
Devices
The availability of OTP devices is especially useful for
customers who need the flexibility for frequent code
updates and small volume applications. In addition to
the program memory, the configuration bits must also
be programmed.
2.3 Quick-Turnaround-Production (QTP)
Devices
Microchip offers a QTP Programming Service for
factory production orders. This service is made
available for users who choose not to program a
medium to high quantity of units and whose code pat-
terns have stabilized. The devices are identical to the
OTP devices but with all EPROM locations and config-
uration options already programmed by the factory.
Certain code and prototype verification procedures
apply before production shipments are available.
Please contact your Microchip Technology sales office
for more details.
2.4 Serialized
Quick-Turnaround-Production
(SQTP
SM
) Devices
Microchip offers a unique programming service where
a few user-defined locations in each device are
programmed with different serial numbers. The serial
numbers may be random, pseudo-random or
sequential.
Serial programming allows each device to have a
unique number which can serve as an entry-code,
password or ID number.
PIC16C55X
DS40143C-page 8
Preliminary
1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc.
Preliminary
DS40143C-page 9
PIC16C55X
3.0 ARCHITECTURAL OVERVIEW
The high perf ormance of the PIC16C55X family can be
attributed to a number of architectural features
commonly found in RISC microprocessors. To begin
with, the PIC16C55X uses a Harvard architecture, in
which, program and data are accessed from separate
memories using separate busses. This improves
bandwidth over traditional von Neumann architecture
where program and data are fetched from the same
memory. Separating progr am and data memory further
allows instructions to be sized differently than 8-bit
wide data words. Instruction opcodes are 14-bits wide
making it possible to have all single word instructions.
A 14-bit wide program memory access bus fetches a
14-bit instruction in a single cycle. A tw o-stage pipeline
overlaps fetch and execution of instructions.
Consequently, all instructions (35) execute in a sin-
gle-cycle (200 ns @ 20 MHz) except for program
branches. The table belo w lists the memory (EEPROM
and ROM).
The PIC16C554 addresses 512 x 14 on-chip program
memory. The PIC16C558 addresses 2K x 14 program
memory. All program memory is internal.
The PIC16C55X can directly or indirectly address its
register files or data memory. All special function
registers including the program counter are mapped
into the data memory. The PIC16C55X have an
orthogonal (symmetrical) instruction set that makes it
possible to carry out any operation on any register
using any addressing mode. This symmetrical nature
and lack of ‘special optimal situations’ make program-
ming with the PIC16C55X simple yet efficient. In addi-
tion, the learning curve is reduced significantly.
Device Program
Memory Data
Memory
PIC16C554 512 80
PIC16C558 2K 128
The PIC16C55X devices contain an 8-bit ALU and
working register. The ALU is a general purpose
arithmetic unit. It performs arithmetic and Boolean
functions between data in the working register and any
register file.
The ALU is 8-bits wide and capable of addition,
subtraction, shift and logical operations. Unless
otherwise mentioned, arithmetic operations are two's
complement in nature. In two-operand instructions,
typically one operand is the working register
(W register). The other operand is a file register or an
immediate constant. In single oper and instructions, the
operand is either the W register or a file register.
The W register is an 8-bit working register used for ALU
operations. It is not an addressable register.
Depending on the instruction executed, the ALU may
affect the values of the Carry (C), Digit Carry (DC), and
Zero (Z) bits in the STATUS register . The C and DC bits
operate as a Borrow and Digit Borrow out bit,
respectively, in subtraction. See the
SUBLW
and
SUBWF
instructions for examples.
A simplified block diagram is shown in Figure 3-1, with
a description of the device pins in Table 3-1.
PIC16C55X
DS40143C-page 10
Preliminary
1998 Microchip Technology Inc.
FIGURE 3-1: BLOCK DIAGRAM
Note 1: Higher order bits are from the status register.
Device Program
Memory Data Memory
(RAM)
PIC16C554
PIC16C558 512 x 14
2K x 14 80 x 8
128 x 8
EPROM
Program
Memory
2K x 14
13 Data Bus 8
14
Program
Bus
Instruction reg
Program Counter
8 Level Stack
(13-bit)
RAM
File
Registers
128 x 8
Direct Addr 7
8
Addr MUX
Indirect
Addr
8
FSR reg
STATUS reg
MUX
ALU
W reg
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKIN
OSC2/CLKOUT
MCLR VDD, VSS Timer0
3
PORTA
PORTB
RA1
RA4/T0CKI
RB0/INT
RB7:RB1
8
8
RAM Addr(1)
RA0
RA2
RA3
512 x 14
to 80 x 8 to
1998 Microchip Technology Inc.
Preliminary
DS40143C-page 11
PIC16C55X
TABLE 3-1: PIC16C55X PINOUT DESCRIPTION
Name
DIP
SOIC
Pin #
SSOP
Pin # I/O/P
Type Buffer
Type
Description
OSC1/CLKIN 16 18 I ST/CMOS Oscillator crystal input/external clock source input.
OSC2/CLKOUT 15 17 O — Oscillator crystal output. Connects to crystal or resonator
in crystal oscillator mode. In RC mode, OSC2 pin outputs
CLKOUT which has 1/4 the frequency of OSC1, and
denotes the instruction cycle rate.
MCLR/V
PP
4 4 I/P ST Master clear (reset) input/programming voltage input.
This pin is an active low reset to the device.
RA0 17 19 I/O ST Bi-directional I/O port
RA1 18 20 I/O ST Bi-directional I/O port
RA2 1 1 I/O ST Bi-directional I/O port
RA3 2 2 I/O ST Bi-directional I/O port
RA4/T0CKI 3 3 I/O ST Bi-directional I/O port or external clock input for TMR0.
Output is open drain type.
RB0/INT 6 7 I/O TTL/ST
(1)
Bi-directional I/O port can be software programmed for
internal weak pull-up. RB0/INT can also be selected as
an external interrupt pin.
RB1 7 8 I/O TTL Bi-directional I/O port can be software programmed for
internal weak pull-up.
RB2 8 9 I/O TTL Bi-directional I/O port can be software programmed for
internal weak pull-up.
RB3 9 10 I/O TTL Bi-directional I/O port can be software programmed for
internal weak pull-up.
RB4 10 11 I/O TTL Bi-directional I/O port can be software programmed for
internal weak pull-up. Interrupt on change pin.
RB5 11 12 I/O TTL Bi-directional I/O port can be software programmed for
internal weak pull-up. Interrupt on change pin.
RB6 12 13 I/O TTL/ST
(2)
Bi-directional I/O port can be software programmed for
internal weak pull-up. Interrupt on change pin. Serial pro-
gramming clock.
RB7 13 14 I/O TTL/ST
(2)
Bi-directional I/O port can be software programmed for
internal weak pull-up. Interrupt on change pin. Serial pro-
gramming data.
V
SS
5 5,6 P — Ground reference for logic and I/O pins.
V
DD
14 15,16 P — Positive supply for logic and I/O pins.
Legend: O = output I/O = input/output P = power
— = Not used I = Input ST = Schmitt Trigger input
TTL = TTL input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
Note 2: This buffer is a Schmitt Trigger input when used in serial programming mode.
PIC16C55X
DS40143C-page 12
Preliminary
1998 Microchip Technology Inc.
3.1 Clocking Scheme/Instruction Cycle
The clock input (OSC1/CLKIN pin) is internally divided
by four to generate four non-overlapping quadrature
clocks namely Q1, Q2, Q3 and Q4. Internally, the
program counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the instruction register in Q4. The
instruction is decoded and executed during the
following Q1 through Q4. The clocks and instruction
execution flow are shown in Figure 3-2.
3.2 Instruction Flow/Pipelining
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instr uction fetch and execute are
pipelined such that fetch takes one instruction cycle
while decode and execute takes another instruction
cycle. However, due to the pipelining, each instr uction
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
(Example 3-1).
A fetch cycle begins with the program counter (PC)
incrementing in Q1.
In the e xecution 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 3-2: CLOCK/INSTRUCTION CYCLE
EXAMPLE 3-1: INSTRUCTION PIPELINE FLOW
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Q1
Q2
Q3
Q4
PC
OSC2/CLKOUT
(RC mode)
PC PC+1 PC+2
Fetch INST (PC)
Execute INST (PC-1) Fetch INST (PC+1)
Execute INST (PC) Fetch INST (PC+2)
Execute INST (PC+1)
Internal
phase
clock
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.
1. MOVLW 55h Fetch 1 Execute 1
2. MOVWF PORTB Fetch 2 Execute 2
3. CALL SUB_1 Fetch 3 Execute 3
4. BSF PORTA, BIT3 Fetch 4 Flush
Fetch SUB_1 Execute SUB_1
1998 Microchip Technology Inc.
Preliminary
DS40143C-page 13
PIC16C55X
4.0 MEMORY ORGANIZATION
4.1 Program Memory Organization
The PIC16C55X has a 13-bit prog ram counter capab le
of addressing an 8K x 14 program memory space. Only
the first 512 x 14 (0000h - 01FFh) for the PIC16C554
and 2K x 14 (0000h - 07FFh) for the PIC16C558 are
physically implemented. Accessing a location above
these boundaries will cause a wrap-around within the
first 512 x 14 space PIC16C554 or 2K x 14 space
PIC16C558. The reset v ector is at 0000h and the inter-
rupt vector is at 0004h (Figure 4-1, Figure 4-2).
FIGURE 4-1: PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16C554
PC<12:0>
13
000h
0004
0005
01FFh
0200h
1FFFh
Stack Level 1
Stack Level 8
Reset Vector
Interrupt Vector
On-chip Program
Memory
CALL, RETURN
RETFIE, RETLW
Stack Level 2
FIGURE 4-2: PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16C558
4.2 Data Memory Organization
The data memory (Figure 4-3 and Figure 4-4) is
partitioned into two Banks which contain the general
purpose registers and the special function registers.
Bank 0 is selected when the RP0 bit (STATUS <5>) is
cleared. Bank 1 is selected when the RP0 bit is set.
The Special Function Registers are located in the first
32 locations of each Bank. Register locations 20-6Fh
(Bank0) on the PIC16C554 and 20-7Fh (Bank0) and
A0-BFh (Bank1) on the PIC16C558 are general pur-
pose registers implemented as static RAM. Some spe-
cial purpose registers are mapped in Bank 1.
4.2.1 GENERAL PURPOSE REGISTER FILE
The register file is organized as 80 x 8 in the
PIC16C554 and 128 x 8 in the PIC16C558. Each can
be accessed either directly or indirectly through the File
Select Register , FSR (Section 4.4).
PC<12:0>
13
000h
0004
0005
07FFh
0800h
1FFFh
Stack Level 1
Stack Level 8
Reset Vector
Interrupt Vector
On-chip Program
Memory
CALL, RETURN
RETFIE, RETLW
Stack Level 2
PIC16C55X
DS40143C-page 14 Preliminary 1998 Microchip Technology Inc.
FIGURE 4-3: DATA MEMORY MAP FOR
THE PIC16C554
INDF(1)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PCLATH
INTCON
INDF(1)
OPTION
PCL
STATUS
FSR
TRISA
TRISB
PCLATH
INTCON
PCON
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
20h A0h
General
Purpose
Register
7Fh FFh
Bank 0 Bank 1
File
Address
6Fh
70h
Unimplemented data memory locations, read as '0'.
Note 1: Not a physical register.
File
Address
FIGURE 4-4: DATA MEMORY MAP FOR
THE PIC16C558
INDF(1)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PCLATH
INTCON
INDF(1)
OPTION
PCL
STATUS
FSR
TRISA
TRISB
PCLATH
INTCON
PCON
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
20h A0h
General
Purpose
Register
7Fh FFh
Bank 0 Bank 1
File
Address
BFh
C0h
Unimplemented data memory locations, read as '0'.
Note 1: Not a physical register.
File
Address
General
Purpose
Register
1998 Microchip Technology Inc. Preliminary DS40143C-page 15
PIC16C55X
4.2.2 SPECIAL FUNCTION REGISTERS
The Special Function Registers are registers used by
the CPU and peripheral functions for controlling the
desired operation of the device (Table 4-1). These
registers are static RAM.
The special function registers can be classified into two
sets (core and peripheral). The special function regis-
ters associated with the “core” functions are described
in this section. Those related to the operation of the
peripheral features are described in the section of that
peripheral feature.
TABLE 4-1: SPECIAL REGISTERS FOR THE PIC16C55X
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR Reset
Value on
all other
resets(1)
Bank 0
00h INDF Addressing this location uses contents of FSR to address data memory (not a physical
register) xxxx xxxx xxxx xxxx
01h TMR0 Timer0 Module’s Register xxxx xxxx uuuu uuuu
02h PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
03h STATUS IRP(2) RP1(2) RP0 TO PD Z DC C 0001 1xxx 000q quuu
04h FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
05h PORTA — — — RA4 RA3 RA2 RA1 RA0 ---x xxxx ---u uuuu
06h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu
07h Unimplemented — —
08h Unimplemented — —
09h Unimplemented — —
0Ah PCLATH — — — Write buffer for upper 5 bits of program counter ---0 0000 ---0 0000
0Bh INTCON GIE (3) T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
0Ch Unimplemented — —
0Dh-1Eh Unimplemented — —
1Fh Unimplemented — —
Bank 1
80h INDF Addressing this location uses contents of FSR to address data memory (not a physical
register) xxxx xxxx xxxx xxxx
81h OPTION RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
82h PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
83h STATUS — — RP0 TO PD Z DC C 0001 1xxx 000q quuu
84h FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
85h TRISA — — — TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111
86h TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111
87h Unimplemented — —
88h Unimplemented — —
89h Unimplemented — —
8Ah PCLATH — — — Write buffer for upper 5 bits of program counter ---0 0000 ---0 0000
8Bh INTCON GIE (3) T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
8Ch Unimplemented — —
8Dh Unimplemented — —
8Eh PCON — — — — — — POR — ---- --0- ---- --u-
8Fh-9Eh Unimplemented — —
9Fh Unimplemented — —
Legend: — = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition,
shaded = unimplemented
Note 1: Other (non power-up) resets include MCLR reset and Watchdog Timer reset during normal operation.
Note 2: IRP & RP1bits are reserved, always maintain these bits clear.
Note 3: Bit 6 of INTCON register is reserved for future use. Always maintain this bit as clear.
PIC16C55X
DS40143C-page 16 Preliminary 1998 Microchip Technology Inc.
4.2.2.1 STATUS REGISTER
The STATUS register, shown in Figure 4-5, contains
the arithmetic status of the ALU, the RESET status and
the bank select bits for data memory.
The STATUS register can be the destination for any
instruction, like any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Further more, the TO and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as the destination may be different
than intended.
For example, CLRF STATUS will clear the upper-three
bits and set the Z bit. This lea ves the status register as
000uu1uu (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions be used to alter the STA-
TUS register because these instructions do not affect
any status bits . For other instructions, not affecting any
status bits, see the “Instruction Set Summary”.
Note 1: The IRP and RP1 bits (STATUS<7:6>)
are not used by the PIC16C55X and
should be programmed as ’0'. Use of
these bits as general purpose R/W bits is
NOT recommended, since this may
affect upward compatibility with future
products.
Note 2: The C and DC bits operate as a Borrow
and Digit Borrow out bit, respectively, in
subtraction. See the SUBLW and SUBWF
instructions for examples.
FIGURE 4-5: STATUS REGISTER (ADDRESS 03H OR 83H)
Reserved Reserved R/W-0 R-1 R-1 R/W-x R/W-x R/W-x
IRP RP1 RP0 TO PD Z DC C R = Readable bit
W = Writable bit
- n = Value at POR reset
- x = Unknown at POR reset
bit7 bit0
bit 7: IRP: Register Bank Select bit (used for indirect addressing)
1 = Bank 2, 3 (100h - 1FFh)
0 = Bank 0, 1 (00h - FFh)
The IRP bit is reserved on the PIC16C55X, always maintain this bit clear.
bit 6-5: RP1:RP0: Register Bank Select bits (used for direct addressing)
11 = Bank 3 (180h - 1FFh)
10 = Bank 2 (100h - 17Fh)
01 = Bank 1 (80h - FFh)
00 = Bank 0 (00h - 7Fh)
Each bank is 128 bytes. The RP1 bit is reserved on the PIC16C55X, always maintain this bit clear.
bit 4: TO: Time-out bit
1 = After power-up, CLRWDT instruction, or SLEEP instruction
0 = A WDT time-out occurred
bit 3: PD: Power-down bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 2: Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1: DC: Digit carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWF instructions)(for borrow the polarity is reversed)
1 = A carry-out from the 4th low order bit of the result occurred
0 = No carry-out from the 4th low order bit of the result
bit 0: C: Carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWF instructions)
1 = A carry-out from the most significant bit of the result occurred
0 = No carry-out from the most significant bit of the result occurred
Note: For borrow the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low order bit of
the source register.
1998 Microchip Technology Inc. Preliminary DS40143C-page 17
PIC16C55X
4.2.2.2 OPTION REGISTER
The OPTION register is a readable and writable
register which contains various control bits to configure
the TMR0/WDT prescaler, the external RB0/INT
interrupt, TMR0 and the weak pull-ups on PORTB.
Note: To achieve a 1:1 prescaler assignment for
TMR0, assign the prescaler to the WDT
(PSA = 1).
FIGURE 4-6: OPTION REGISTER (ADDRESS 81H)
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 R = Readable bit
W = Writable bit
- n = Value at POR reset
bit7 bit0
bit 7: RBPU: PORTB Pull-up Enable bit
1 = PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual port latch values
bit 6: INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of RB0/INT pin
0 = Interrupt on falling edge of RB0/INT pin
bit 5: T0CS: TMR0 Clock Source Select bit
1 = Transition on RA4/T0CKI pin
0 = Internal instruction cycle clock (CLKOUT)
bit 4: T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on RA4/T0CKI pin
0 = Increment on low-to-high transition on RA4/T0CKI pin
bit 3: PSA: Prescaler Assignment bit
1 = Prescaler is assigned to the WDT
0 = Prescaler is assigned to the Timer0 module
bit 2-0: PS2:PS0: Prescaler Rate Select bits
000
001
010
011
100
101
110
111
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
Bit Value TMR0 Rate WDT Rate
PIC16C55X
DS40143C-page 18 Preliminary 1998 Microchip Technology Inc.
4.2.2.3 INTCON REGISTER
The INTCON register is a readable and writable
register which contains the various enab le and flag bits
for all interrupt sources.
Note: Interrupt flag bits get set when an interrupt
condition occurs regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>).
FIGURE 4-7: INTCON REGISTER (ADDRESS 0BH OR 8BH)
R/W-0 Reserved R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x
GIE — T0IE INTE RBIE T0IF INTF RBIF R = Readable bit
W = Writable bit
- n = Value at POR reset
- x = Unknown at POR reset
bit7 bit0
bit 7: GIE: Global Interrupt Enable bit
1 = Enables all un-masked interrupts
0 = Disables all interrupts
bit 6: — = Reserved for future use. Always maintain this bit clear.
bit 5: T0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 interrupt
0 = Disables the TMR0 interrupt
bit 4: INTE: RB0/INT External Interrupt Enable bit
1 = Enables the RB0/INT external interrupt
0 = Disables the RB0/INT external interrupt
bit 3: RBIE: RB Port Change Interrupt Enable bit
1 = Enables the RB port change interrupt
0 = Disables the RB port change interrupt
bit 2: T0IF: TMR0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed (must be cleared in software)
0 = TMR0 register did not overflow
bit 1: INTF: RB0/INT External Interrupt Flag bit
1 = The RB0/INT external interrupt occurred (must be cleared in software)
0 = The RB0/INT external interrupt did not occur
bit 0: RBIF: RB Port Change Interrupt Flag bit
1 = When at least one of the RB7:RB4 pins changed state (must be cleared in software)
0 = None of the RB7:RB4 pins have changed state
1998 Microchip Technology Inc. Preliminary DS40143C-page 19
PIC16C55X
4.2.2.4 PCON REGISTER
The PCON register contains flag bits to differentiate
between a Po wer-on Reset, an e xternal MCLR reset or
WDT reset. See Section 7.3 and Section 7.4 for
detailed reset operation.
FIGURE 4-8: PCON REGISTER (ADDRESS 8Eh)
U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 U-0
— — — — — — POR — R = Readable bit
W = Writable bit
U = Unimplemented bit,
read as ‘0’
- n = Value at POR reset
bit7 bit0
bit 7-2: Unimplemented: Read as '0'
bit 1: POR: Power-on Reset Status bit
1 = No Power-on Reset occurred
0 = Power-on Reset occurred
bit 0: Unimplemented: Read as '0'
PIC16C55X
DS40143C-page 20 Preliminary 1998 Microchip Technology Inc.
4.3 PCL and PCLATH
The program counter (PC) is 13-bits wide. The low byte
comes from the PCL register, which is a readable and
writable register . The high bits (PC<12:8>) are not directly
readable or writable and come from PCLATH. On any
reset, the PC is cleared. Figure 4-9 shows the two
situations f or the loading of the PC. The upper e xample in
the figure shows ho w the PC is loaded on a write to PCL
(PCLATH<4:0> → PCH). The lower e xample in Figure 4-9
shows how the PC is loaded during a CALL or GOTO
instruction (PCLATH<4:3> → PCH).
FIGURE 4-9: LOADING OF PC IN
DIFFERENT SITUATIONS
4.3.1 COMPUTED GOTO
A computed GOTO is accomplished by adding an
offset to the program counter (ADDWF PCL). When
doing a table read using a computed GOTO method,
care should be e x ercised if the tab le location crosses a
PCL memory boundary (each 256 byte bloc k). Ref er to
the application note
“Implementing a Table Read"
(AN556).
PC 12 8 7 0
5PCLATH<4:0>
PCLATH
Instruction with
ALU result
GOTO, CALL
Opcode <10:0>
8
PC 12 11 10 0
11
PCLATH<4:3>
PCH PCL
8 7
2
PCLATH
PCH PCL
PCL as
Destination
4.3.2 STACK
The PIC16C55X family has an 8 level deep x 13-bit
wide hardware stack (Figure 4-1 and Figure 4-2). The
stack space is not part of either program or data space
and the stack pointer is not readable or writable. The
PC is PUSHed onto the stack when a CALL instruction
is executed or an interrupt causes a branch. The stack
is POP ed in the e vent of a RETURN, RETLW or a RETFIE
instruction execution. PCLATH is not affected by a
PUSH or POP operation.
The stack oper ates as a circular buff er . This means that
after the stack has been PUSHed eight times , the ninth
push ov erwrites the v alue that w as stored from the first
push. The tenth push overwrites the second push (and
so on).
Note 1: There are no STATUS bits to indicate
stack overflow or stack underflow
conditions.
Note 2: There are no instructions mnemonics
called PUSH or POP. These are actions
that occur from the execution of the
CALL, RETURN, RETLW and RETFIE
instructions, or vectoring to an interrupt
address.
1998 Microchip Technology Inc. Preliminary DS40143C-page 21
PIC16C55X
4.4 Indirect Addressing, INDF and FSR
Registers
The INDF register is not a ph ysical register . Addressing
the INDF register will cause indirect addressing.
Indirect addressing is possible by using the INDF reg-
ister. Any instruction using the INDF register actually
accesses data pointed to by the file select register
(FSR). Reading INDF itself indirectly will produce 00h.
Writing to the INDF register indirectly results in a
no-operation (although status bits ma y be aff ected). An
effective 9-bit address is obtained b y concatenating the
8-bit FSR register and the IRP bit (STATUS<7>), as
shown in Figure 4-10. However, IRP is not used in the
PIC16C55X.
A simple program to clear RAM locations 20h-2Fh
using indirect addressing is shown in Example 4-1.
EXAMPLE 4-1: INDIRECT ADDRESSING
movlw 0x20 ;initialize pointer
movwf FSR ;to RAM
N
EXT clrf INDF ;clear INDF register
incf FSR ;inc pointer
btfss FSR,4 ;all done?
goto NEXT ;no clear next
;yes continue
CONTINUE:
FIGURE 4-10: DIRECT/INDIRECT ADDRESSING PIC16C55X
For memory map detail see Figure 4-3 and Figure 4-4.
Note 1: The RP1 and IRP bits are reserved, always maintain these bits clear.
Data
Memory
Indirect AddressingDirect Addressing
bank select location select
(1)RP1 RP0 6 0
from opcode IRP(1) FSR register
70
bank select location select
00 01 10 11 00h
7Fh
00h
7Fh Bank 0 Bank 1 Bank 2 Bank 3
not used
PIC16C55X
DS40143C-page 22 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 23
PIC16C55X
5.0 I/O PORTS
The PIC16C55X hav e tw o ports, PORTA and PORTB .
5.1 PORTA and TRISA Registers
PORTA is a 5-bit wide latch. RA4 is a Schmitt Trigger input
and an open drain output. Port RA4 is multiple xed with the
T0CKI clock input. All other RA port pins have Schmitt
Trigger input lev els and full CMOS output driv ers. All pins
have data direction bits (TRIS registers) which can config-
ure these pins as input or output.
A '1' in the TRISA register puts the corresponding output
driver in a hi- impedance mode. A '0' in the TRISA register
puts the contents of the output latch on the selected pin(s).
Reading the PORTA register reads the status of the pins,
whereas writing to it will wr ite to the por t latch. All write
operations are read-modify-write operations. So a write
to a port implies that the port pins are first read, then this
value is modified and written to the port data latch.
FIGURE 5-1: BLOCK DIAGRAM OF
PORT PINS RA<3:0>
Note: On reset, the TRISA register is set to all inputs.
Data
bus
Q
D
Q
CK
QD
Q
CK
Q D
EN
P
N
WR
PortA
WR
TRISA
Data Latch
TRIS Latch
RD TRISA
RD PORTA
Schmitt
input
buffer
VSS
VDD
I/O pin
Trigger
VSS
VDD
FIGURE 5-2: BLOCK DIA GRAM OF RA4 PIN
Data
bus
WR
PORTA
WR
TRISA
RD PORTA
Data Latch
TRISA Latch
RD TRISA
Schmitt
Trigger
input
buffer
N
VSS
I/O pin(1)
TMR0 clock input
QD
Q
CK
QD
Q
CK
EN
Q D
EN
VSS
PIC16C55X
DS40143C-page 24 Preliminary 1998 Microchip Technology Inc.
TABLE 5-1: PORTA FUNCTIONS
TABLE 5-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name Bit # Buffer
Type Function
RA0 bit0 ST Bi-directional I/O port.
RA1 bit1 ST Bi-directional I/O port.
RA2 bit2 ST Bi-directional I/O port.
RA3 bit3 ST Bi-directional I/O port.
RA4/T0CKI bit4 ST Bi-directional I/O port or external clock input for TMR0. Output is open
drain type.
Legend: ST = Schmitt Trigger input
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR Value on
All Other Resets
05h PORTA — — — RA4 RA3 RA2 RA1 RA0 ---x xxxx ---u uuuu
85h TRISA — — — TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111
Legend: — = Unimplemented locations, read as ‘0’
x = unknown
u = unchanged
Note: Shaded bits are not used by PORTA.
1998 Microchip Technology Inc. Preliminary DS40143C-page 25
PIC16C55X
5.2 PORTB and TRISB Registers
PORTB is an 8-bit wide bi-directional port. The
corresponding data direction register is TRISB. A '1' in
the TRISB register puts the corresponding output driver
in a high impedance mode. A '0' in the TRISB register
puts the contents of the output latch on the selected
pin(s).
Reading PORTB 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. So a write
to a port implies that the port pins are first read, then
this value is modified and written to the port data latch.
Each of the PORTB pins has a weak internal pull-up
(≈200 µA typical). A single control bit can turn on all the
pull-ups. This is done by clearing the RBPU
(OPTION<7>) bit. The weak pull-up is automatically
turned off when the port pin is configured as an output.
The pull-ups are disabled on Power-on Reset.
Four of PORTB’s pins, RB7:RB4, have an interrupt on
change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupt
on change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RBIF interrupt (flag
latched in INTCON<0>). This interrupt can wake the
device from SLEEP. The user, in the interrupt service
routine, can clear the interrupt in the f ollo wing manner:
a) Any read or write of PORTB. This will end the
mismatch condition.
b) Clear flag bit RBIF.
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition, and
allow flag bit RBIF to be cleared.
This interrupt on mismatch feature, together with
software configurable pull-ups on these four pins allow
easy interface to a key pad and make it possible for
wake-up on key-depression. (See AN552 in the
Microchip
Embedded Control Handbook
.)
The interrupt on change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt on change
feature. Polling of PORTB is not recommended while
using the interrupt on change feature.
Note: If a change on the I/O pin should occur when the
read operation is being executed (start of the Q2
cycle), then the RBIF interrupt flag may not
get set.
FIGURE 5-3: BLOCK DIAGRAM OF RB7:RB4 PINS
P
N
VSS
VDD
Data Latch
From other
RBPU(1)
P
VDD
I/O
Data bus
WR PortB
WR TRISB
Set RBIF
TRIS Latch
RD TRISB
RD PortB
RB7:RB4 pins
weak
pull-up
RD Port B
Latch
TTL
Input
Buffer
pin
Note 1: TRISB = 1 enables weak pull-up if RBPU = '0'
(OPTION<7>).
ST
Buffer
RB7:RB6 in serial programming mode
VDD
VSS
QD
CK
QD
Q
CK
EN
QD
EN
Q D
PIC16C55X
DS40143C-page 26 Preliminary 1998 Microchip Technology Inc.
FIGURE 5-4: BLOCK DIAGRAM OF RB3:RB0 PINS
TABLE 5-3: PORTB FUNCTIONS
TABLE 5-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Name Bit # Buffer Type Function
RB0/INT bit0 TTL/ST(1) Input/output or external interrupt input. Internal software programmable
weak pull-up.
RB1 bit1 TTL Input/output pin. Internal software programmable weak pull-up.
RB2 bit2 TTL Input/output pin. Internal software programmable weak pull-up.
RB3 bit3 TTL Input/output pin. Internal software programmable weak pull-up.
RB4 bit4 TTL Input/output pin (with interrupt on change). Internal software
programmable weak pull-up.
RB5 bit5 TTL Input/output pin (with interrupt on change). Internal software
programmable weak pull-up.
RB6 bit6 TTL/ST(2) Input/output pin (with interrupt on change). Internal software
programmable weak pull-up. Serial programming clock pin.
RB7 bit7 TTL/ST(2) Input/output pin (with interrupt on change). Internal software
programmable weak pull-up. Serial programming data pin.
Legend: ST = Schmitt Trigger, TTL = TTL input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
Note 2: This buffer is a Schmitt Trigger input when used in serial programming mode.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR Value on
All Other Rests
06h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu
86h TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111
81h OPTION RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
Legend: x = unknown, u = unchanged
Note: Shaded bits are not used by PORTB.
Note 1: TRISB = 1 enables weak pull-up if RBPU = '0'
(OPTION<7>).
P
N
VSS
VDD
RBPU(1)
P
VDD
I/O
Data bus
WR PortB
WR TRISB
RD TRISB
RD PortB
weak
pull-up
RD Port B
Latch
TTL
Input
Buffer
pin
ST
Buffer
RB0:INT
VDD
VSS
ST
Buffer
EN
QD
Data Latch
TRIS Latch
QD
CK
QD
Q
CK
1998 Microchip Technology Inc. Preliminary DS40143C-page 27
PIC16C55X
5.3 I/O Programming Considerations
5.3.1 BI-DIRECTIONAL I/O PORTS
Any instruction which writes, operates internally as a
read followed by a write operation. The BCF and BSF
instructions, for example, read the register into the
CPU, execute the bit operation and write the result back
to the register. Caution must be used when these
instructions are applied to a por t with both inputs and
outputs defined. For example, a BSF operation on bit5
of POR TB will cause all eight bits of POR TB to be read
into the CPU. Then the BSF operation takes place on
bit5 and PORTB is written to the output latches. If
another bit of PORTB is used as a bidirectional I/O pin
(e.g., bit0) and it is defined as an input at this time, the
input signal present on the pin itself would be read into
the CPU and re-written to the data latch of this
particular pin, ov erwriting the pre vious content. As long
as the pin stays in the input mode, no problem occurs.
However, if bit0 is switched into output mode later on,
the content of the data latch may now be unknown.
Reading the port register, reads the values of the port
pins. Writing to the port register writes the value to the
port latch. When using read modify write instructions
(ex. BCF, BSF, etc.) on a por t, the value of the por t pins
is read, the desired operation is done to this v alue , and
this value is then written to the port latch.
Example 5-1 shows the effect of two sequential
read-modify-write instr uctions (ex., BCF, BSF, etc.) on
an I/O port.
A pin actively outputting a Low or High should not be
driven from external devices at the same time in order
to change the le vel on this pin (“wired-or”, “wired-and”).
The resulting high output currents may damage
the chip.
EXAMPLE 5-1: READ-MODIFY-WRITE
INSTRUCTIONS ON AN
I/O PORT
5.3.2 SUCCESSIVE OPER ATIONS ON I/O PORTS
The actual write to an I/O port happens at the end of an
instruction cycle, whereas for reading, the data must be
valid at the beginning of the instruction cycle
(Figure 5-5). Therefore, care must be exercised if a
write followed by a read operation is carried out on the
same I/O port. The sequence of instructions should be
such to allow the pin voltage to stabilize (load
dependent) before the next instruction which causes
that file to be read into the CPU is e xecuted. Otherwise ,
the pre vious state of that pin ma y be read into the CPU
rather than the new state. When in doubt, it is better to
separate these instructions with an NOP or another
instruction not accessing this I/O port.
;
;Initial PORT settings: PORTB<7:4> Inputs
; PORTB<3:0> Outputs
;
;PORTB<7:6> have external pull-up and are not
connected to other circuitry
;
; PORT latch PORT pins
;---------- ----------
BCF PORTB, 7 ; 01pp pppp 11pp pppp
BCF PORTB, 6 ; 10pp pppp 11pp pppp
BSF STATUS,RP0 ;
BCF TRISB, 7 ; 10pp pppp 11pp pppp
BCF TRISB, 6 ; 10pp pppp 10pp pppp
;
; Note that the user may have expected the pin
; values to be 00pp pppp. The 2nd BCF caused
; RB7 to be latched as the pin value (High).
FIGURE 5-5: SUCCESSIVE I/O OPERATION
Note:
This example shows write to PORTB
followed by a read from PORTB.
Note that:
data setup time = (0.25 TCY - TPD)
where TCY = instruction cycle and
TPD = propagation delay of Q1 cycle
to output valid.
Therefore, at higher clock frequencies,
a write followed by a read may be
problematic.
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RB <7:0>
Port pin
sampled here
PC PC + 1 PC + 2 PC + 3
NOPNOPMOVF PORTB, W
Read PORTB
MOVWF PORTB
Write to
PORTB
PC
Instruction
fetched
TPD
Execute
MOVWF
PORTB
Execute
MOVF
PORTB, W
Execute
NOP
RB7:RB0
PIC16C55X
DS40143C-page 28 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 29
PIC16C55X
6.0 TIMER0 MODULE
The Timer0 module timer/counter has the following
features:
•8-bit timer/counter
• Readable and writable
• 8-bit software programmable prescaler
• Internal or external clock select
• Interrupt on overflow from FFh to 00h
• Edge select for external clock
Figure 6-1 is a simplified block diagram of the Timer0
module.
Timer mode is selected by clearing the T0CS bit
(OPTION<5>). In timer mode, the TMR0 will increment
every instr uction cycle (without prescaler). If Timer0 is
written, the increment is inhibited for the following two
cycles (Figure 6-2 and Figure 6-3). The user can work
around this by writing an adjusted value to TMR0.
Counter mode is selected by setting the T0CS bit. In
this mode Timer0 will increment either on every rising
or falling edge of pin RA4/T0CKI. The incrementing
edge is determined by the source edge (T0SE) control
bit (OPTION<4>). Clearing the T0SE bit selects the
rising edge. Restrictions on the e xternal clock input are
discussed in detail in Section 6.2.
The prescaler is shared between the Timer0 module
and the WatchdogTimer. The prescaler assignment is
controlled in software by the control bit PSA
(OPTION<3>). Clearing the PSA bit will assign the
prescaler to Timer0. The prescaler is not readable or
writable. When the prescaler is assigned to the Timer0
module, prescale value of 1:2, 1:4, ..., 1:256 are
selectable. Section 6.3 details the operation of the
prescaler.
6.1 TIMER0 Interrupt
Timer0 interrupt is generated when the TMR0 register
timer/counter overflows from FFh to 00h. This overflow
sets the T0IF bit. The interrupt can be masked by
clearing the T0IE bit (INTCON<5>). The T0IF bit
(INTCON<2>) must be cleared in software by the
Timer0 module interrupt service routine before
re-enabling this interrupt. The Timer0 interrupt cannot
wake the processor from SLEEP since the timer is shut
off during SLEEP. See Figure 6-4 for Timer0 interrupt
timing.
FIGURE 6-1: TIMER0 BLOCK DIAGRAM
FIGURE 6-2: TIMER0 (TMR0) TIMING: INTERNAL CLOCK/NO PRESCALER
Note 1: Bits, T0SE, T0CS, PS2, PS1, PS0 and PSA are located in the OPTION register.
2: The prescaler is shared with Watchdog Timer (Figure 6-6)
RA4/T0CKI
T0SE
0
1
1
0
pin
T0CS
FOSC/4
Programmable
Prescaler
Sync with
Internal
clocks TMR0
PSout
(2 Tcy delay)
PSout
Data bus
8
Set Flag bit T0IF
on Overflow
PSA
PS2:PS0
PC-1
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 Q1 Q2 Q3 Q4
PC
(Program
Counter)
Instruction
Fetch
TMR0
PC PC+1 PC+2 PC+3 PC+4 PC+5 PC+6
T0 T0+1 T0+2 NT0 NT0 NT0 NT0+1 NT0+2 T0
MOVWF TMR0 MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W
Write TMR0
executed Read TMR0
reads NT0 Read TMR0
reads NT0 Read TMR0
reads NT0 Read TMR0
reads NT0 + 1 Read TMR0
reads NT0 + 2
Instruction
Executed
PIC16C55X
DS40143C-page 30 Preliminary 1998 Microchip Technology Inc.
FIGURE 6-3: TIMER0 TIMING: INTERNAL CLOCK/PRESCALE 1:2
FIGURE 6-4: TIMER0 INTERRUPT TIMING
PC-1
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 Q1 Q2 Q3 Q4
PC
(Program
Counter)
Instruction
Fetch
TMR0
PC PC+1 PC+2 PC+3 PC+4 PC+5 PC+6
T0 NT0+1
MOVWF TMR0 MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W
Write TMR0
executed Read TMR0
reads NT0 Read TMR0
reads NT0 Read TMR0
reads NT0 Read TMR0
reads NT0 Read TMR0
reads NT0 + 1
T0+1 NT0
Instruction
Execute
Q2Q1 Q3 Q4Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
11
OSC1
CLKOUT(3)
TMR0 timer
T0IF bit
(INTCON<2>)
FEh
GIE bit
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
fetched
PC PC +1 PC +1 0004h 0005h
Instruction
executed
Inst (PC)
Inst (PC-1)
Inst (PC+1)
Inst (PC)
Inst (0004h) Inst (0005h)
Inst (0004h)Dummy cycle Dummy cycle
FFh 00h 01h 02h
Note 1: T0IF interrupt flag is sampled here (every Q1).
2: Interrupt latency = 4Tcy, where Tcy = instruction cycle time.
3: CLKOUT is available only in RC oscillator mode.
Interrupt Latency Time
1998 Microchip Technology Inc. Preliminary DS40143C-page 31
PIC16C55X
6.2 Using Timer0 with External Clock
When an e xternal clock input is used f or Timer0, it must
meet certain requirements. The external clock
requirement is due to internal phase clock (TOSC)
synchronization. Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
6.2.1 EXTERNAL CLOCK SYNCHRONIZATION
When no prescaler is used, the exter nal clock input is
the same as the prescaler output. The synchronization
of T0CKI with the internal phase clocks is
accomplished by sampling the prescaler output on the
Q2 and Q4 cycles of the internal phase clocks
(Figure 6-5). Therefore, it is necessary for T0CKI to be
high f or at least 2TOSC (and a small RC delay of 20 ns)
and low for at least 2TOSC (and a small RC delay of
20 ns). Refer to the electrical specification of the
desired device.
When a prescaler is used, the external clock input is
divided by the asynchronous ripple-counter type
prescaler so that the prescaler output is symmetrical.
For the external clock to meet the sampling
requirement, the ripple-counter must be taken into
account. Therefore, it is necessary for T0CKI to have a
period of at least 4TOSC (and a small RC delay of
40 ns) divided by the prescaler value. The only
requirement on T0CKI high and lo w time is that they do
not violate the minimum pulse width requirement of
10 ns. Refer to parameters 40, 41 and 42 in the
electrical specification of the desired device.
6.2.2 TIMER0 INCREMENT DELAY
Since the prescaler output is synchronized with the
internal clocks, there is a small delay from the time the
external clock edge occurs to the time the TMR0 is
actually incremented. Figure 6-5 shows the delay from
the external clock edge to the timer incrementing.
FIGURE 6-5: TIMER0 TIMING WITH EXTERNAL CLOCK
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
External Clock Input or
Prescaler output (2)
External Clock/Prescaler
Output after sampling
Increment Timer0 (Q4)
Timer0 T0 T0 + 1 T0 + 2
Small pulse
misses sampling
Note 1: Delay from clock input change to Timer0 increment is 3Tosc to 7Tosc. (Duration of Q = Tosc).
Therefore, the error in measuring the interval between two edges on Timer0 input = ±4Tosc max.
2: External clock if no prescaler selected, Prescaler output otherwise.
3: The arrows indicate the points in time where sampling occurs.
(3) (1)
PIC16C55X
DS40143C-page 32 Preliminary 1998 Microchip Technology Inc.
6.3 Prescaler
An 8-bit counter is available as a prescaler for the
Timer0 module, or as a postscaler for the Watchdog
Timer, respectively (Figure 6-6). For simplicity, this
counter is being referred to as “prescaler” throughout
this data sheet. Note that there is only one prescaler
available which is mutually exclusive between the
Timer0 module and the Watchdog Timer. Thus, a
prescaler assignment for the Timer0 module means
that there is no prescaler for the Watchdog Timer, and
vice-versa.
The PSA and PS2:PS0 bits (OPTION<3:0>) determine
the prescaler assignment and prescale ratio.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF 1, MOVWF 1,
BSF 1,x....etc.) will clear the prescaler. When
assigned to WDT, a CLRWDT instruction will clear the
prescaler along with the Watchdog Timer. The
prescaler is not readable or writable.
FIGURE 6-6: BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
T0CKI
T0SE
pin
M
U
X
CLKOUT (=Fosc/4)
SYNC
2
Tcy TMR0 reg
8-bit Prescaler
8-to-1MUX
M
U
X
M U X
Watchdog
Timer
PSA
01
0
1
WDT
Time-out
PS0 - PS2
8
Note: T0SE, T0CS, PSA, PS0-PS2 are bits in the OPTION register.
PSA
WDT Enable bit
M
U
X
0
10
1
Data Bus
Set flag bit T0IF
on Overflow
8
PSA
T0CS
1998 Microchip Technology Inc. Preliminary DS40143C-page 33
PIC16C55X
6.3.1 SWITCHING PRESCALER ASSIGNMENT
The prescaler assignment is fully under software
control (i.e., it can be changed “on the fly” during
program execution). To avoid an unintended device
RESET, the following instruction sequence
(Example 6-1) must be executed when changing the
prescaler assignment from Timer0 to WDT. Lines 5-7
are required only if the desired postscaler rate is 1:1
(PS<2:0> = 000) or 1:2 (PS<2:0> = 001).
EXAMPLE 6-1: CHANGING PRESCALER
(TIMER0→WDT)
1.BCF STATUS, RP0 ;Skip if already in
; Bank 0
2.CLRWDT ;Clear WDT
3.CLRF TMR0 ;Clear TMR0 & Prescaler
4.BSF STATUS, RP0 ;Bank 1
5.MOVLW '00101111’b; ;These 3 lines (5, 6, 7)
6.MOVWF OPTION ; are required only if
; desired PS<2:0> are
7.CLRWDT ; 000 or 001
8.MOVLW '00101xxx’b ;Set Postscaler to
9.MOVWF OPTION ; desired WDT rate
10.BCF STATUS, RP0 ;Return to Bank 0
To change prescaler from the WDT to the TMR0
module use the sequence shown in Example 6-2. This
precaution must be taken even if the WDT is disabled.
EXAMPLE 6-2: CHANGING PRESCALER
(WDT→TIMER0)
CLRWDT ;Clear WDT and
;prescaler
BSF STATUS, RP0
MOVLW b'xxxx0xxx' ;Select TMR0, new
;prescale value and
;clock source
MOVWF OPTION
BCF STATUS, RP0
TABLE 6-1: REGISTERS ASSOCIATED WITH TIMER0
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR Value on
All Other Resets
01h TMR0 Timer0 module’s register xxxx xxxx uuuu uuuu
0Bh/8Bh INTCON GIE + T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000x
81h OPTION RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
85h TRISA — — — TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111
Legend: — = Unimplemented locations, read as ‘0’.
+ = Reserved for future use.
Note: Shaded bits are not used by TMR0 module.
PIC16C55X
DS40143C-page 34 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 35
PIC16C55X
7.0 SPECIAL FEATURES OF THE
CPU
What sets a microcontroller apart from other
processors are special circuits to deal with the needs of
real time applications. The PIC16C55X family has a
host of such features intended to maximize system
reliability, minimize cost through elimination of external
components, provide power saving operating modes
and offer code protection.
These are:
1. OSC selection
2. Reset
Power-on Reset (POR)
Power-up Timer (PWRT)
Oscillator Start-Up Timer (OST)
3. Interrupts
4. Watchdog Timer (WDT)
5. SLEEP
6. Code protection
7. ID Locations
8. In-circuit serial programming™
The PIC16C55X has a Watchdog Timer which is
controlled by configuration bits. It runs off its own RC
oscillator f or added reliability. There are two timers that
offer necessary delays on power-up. One is the
Oscillator Start-up Timer (OST), intended to keep the
chip in reset until the crystal oscillator is stable. The
other is the Po w er-up Timer (PWRT), which pro vides a
fixed delay of 72 ms (nominal) on power-up only,
designed to keep the part in reset while the power
supply stabilizes. With these two functions on-chip,
most applications need no external reset circuitry.
The SLEEP mode is designed to offer a very low
current power-do wn mode . The user can w ak e-up from
SLEEP through external reset, Watchdog Timer
wake-up or through an interrupt. Several oscillator
options are also made available to allow the par t to fit
the application. The RC oscillator option saves system
cost while the LP crystal option saves power. A set of
configuration bits are used to select various options.
PIC16C55X
DS40143C-page 36 Preliminary 1998 Microchip Technology Inc.
7.1 Configuration Bits
The configuration bits can be progr ammed (read as '0')
or left unprogrammed (read as '1') to select various
device configurations. These bits are mapped in
program memory location 2007h.
The user will note that address 2007h is beyond
the user program memory space. In fact, it belongs
to the special test/configuration memory space
(2000h – 3FFFh), which can be accessed only during
programming.
FIGURE 7-1: CONFIGURATION WORD
CP1 CP01CP1 CP01CP1 CP01—Reserved CP1 CP01PWRTE WDTE F0SC1 F0SC0 CONFIG Address
REGISTER: 2007h
bit13 bit0
bit 13-8 CP<1:0>: Code protection bits(1)
5-4: 11 = Program Memory code protection off
10 = 0400h - 07FFh code protected
01 = 0200h - 07FFh code protected
11 = 0000h - 07FFh code protected
bit 7: Unimplemented: Read as '1'
bit 6: Reserved: Do not use
bit 3: PWRTE: Power-up Timer Enable bit
1 = PWRT disabled
0 = PWRT enabled
bit 2: WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled
bit 1-0: FOSC1:FOSC0: Oscillator Selection bits
11 = RC oscillator
10 = HS oscillator
01 = XT oscillator
00 = LP oscillator
Note 1: All of the CP1:CP0 pairs hav e to be giv en the same value to enab le the code protection scheme listed.
1998 Microchip Technology Inc. Preliminary DS40143C-page 37
PIC16C55X
7.2 Oscillator Configurations
7.2.1 OSCILLATOR TYPES
The PIC16C55X can be operated in four different
oscillator options. The user can program two
configuration bits (FOSC1 and FOSC0) to select one of
these four modes:
• LP Low Power Crystal
• XT Crystal/Resonator
• HS High Speed Crystal/Resonator
• RC Resistor/Capacitor
7.2.2 CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
In XT, LP or HS modes a cr ystal or ceramic resonator
is connected to the OSC1 and OSC2 pins to establish
oscillation (Figure 7-2). The PIC16C55X oscillator
design requires the use of a parallel cut crystal. Use of
a series cut crystal may give a frequency out of the
crystal manuf acturers specifications. When in XT, LP or
HS modes, the device can have an external clock
source to drive the OSC1 pin (Figure 7-3).
FIGURE 7-2: CRYSTAL OPERATION
(OR CERAMIC RESONATOR)
(HS, XT OR LP OSC
CONFIGURATION)
FIGURE 7-3: EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
See Table 7-1 and Table 7-2 for recommended
values of C1 and C2.
Note: A series resistor may be required for
AT strip cut crystals.
C1
C2
XTAL
OSC2
RS
OSC1
RF SLEEP
To internal logic
PIC16C55X
see Note
Clock from
ext. system PIC16C55X
OSC1
OSC2
Open
TABLE 7-1: CAPACITOR SELECTION
FOR CERAMIC RESONATORS
(PRELIMINARY)
TABLE 7-2: CAPACITOR SELECTION
FOR CRYSTAL OSCILLATOR
(PRELIMINARY)
Ranges Characterized:
Mode Freq OSC1(C1) OSC2(C2)
XT 455 kHz
2.0 MHz
4.0 MHz
22 - 100 pF
15 - 68 pF
15 - 68 pF
22 - 100 pF
15 - 68 pF
15 - 68 pF
HS 8.0 MHz
16.0 MHz 10 - 68 pF
10 - 22 pF 10 - 68 pF
10 - 22 pF
Higher capacitance increases the stability of the oscillator
but also increases the start-up time. These values are for
design guidance only. Since each resonator has its own
characteristics, the user should consult with the resonator
manufacturer for appropriate values of external compo-
nents.
Mode Freq OSC1(C1) OSC2(C2)
LP 32 kHz
200 kHz 68 - 100 pF
15 - 30 pF 68 - 100 pF
15 - 30 pF
XT 100 kHz
2 MHz
4 MHz
68 - 150 pF
15 - 30 pF
15 - 30 pF
150 - 200 pF
15 - 30 pF
15 - 30 pF
HS 8 MHz
10 MHz
20 MHz
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
Higher capacitance increases the stability of the oscillator
but also increases the start-up time. These values are for
design guidance only. Rs may be required in HS mode as
well as XT mode to avoid overdriving crystals with low drive
level specification. Since each crystal has its own
characteristics, the user should consult with the crystal
manufacturer for appropriate values of external compo-
nents.
PIC16C55X
DS40143C-page 38 Preliminary 1998 Microchip Technology Inc.
7.2.3 EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
Either a pre-packaged oscillator can be used or a sim-
ple oscillator circuit with TTL gates can be built.
Prepackaged oscillators provide a wide operating
range and better stability. A well-designed crystal
oscillator will provide good performance with TTL
gates. Two types of crystal oscillator circuits can be
used; one with series resonance, or one with parallel
resonance.
Figure 7-4 shows implementation of a parallel resonant
oscillator circuit. The circuit is designed to use the
fundamental frequency of the crystal. The 74AS04
inverter performs the 180° phase shift that a parallel
oscillator requires. The 4.7 kΩ resistor provides the
negative feedback for stability. The 10 kΩ
potentiometers bias the 74AS04 in the linear region.
This could be used for external oscillator designs.
FIGURE 7-4: EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
Figure 7-5 shows a series resonant oscillator circuit.
This circuit is also designed to use the fundamental
frequency of the crystal. The inver ter perfor ms a 180°
phase shift in a series resonant oscillator circuit. The
330 Ω resistors provide the negative feedback to bias
the inverters in their linear region.
FIGURE 7-5: EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
20 pF
+5V
20 pF
10k 4.7k
10k
74AS04
XTAL
10k
74AS04 PIC16C55X
CLKIN
To other
Devices
330 Ω
74AS04 74AS04 PIC16C55X
CLKIN
To other
Devices
XTAL
330 Ω
74AS04
0.1 µF
7.2.4 RC OSCILLATOR
For timing insensitive applications the “RC” device
option offers additional cost savings. The RC oscillator
frequency is a function of the supply voltage, the
resistor (Rext) and capacitor (Cext) values, and the
operating temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal
process parameter variation. Furthermore, the
difference in lead frame capacitance between pac kage
types will also affect the oscillation frequency,
especially for low Cext values. The user also needs to
take into account variation due to tolerance of external
R and C components used. Figure 7-6 shows how the
R/C combination is connected to the PIC16C55X. For
Rext values below 2.2 kΩ, the oscillator operation may
become unstable, or stop completely. For very high
Rext values (e.g., 1 MΩ), the oscillator becomes
sensitive to noise, humidity and leakage. Thus, we
recommend to keep Rext between 3 kΩ and 100 kΩ.
Although the oscillator will operate with no external
capacitor (Cext = 0 pF), we recommend using values
above 20 pF for noise and stability reasons. With no or
small external capacitance, the oscillation frequency
can vary dramatically due to changes in external
capacitances, such as PCB trace capacitance or
package lead frame capacitance.
The oscillator frequency, divided by 4, is available on
the OSC2/CLKOUT pin, and can be used for test
purposes or to synchronize other logic (Figure 3-2 for
waveform).
FIGURE 7-6: RC OSCILLATOR MODE
OSC2/CLKOUT
Cext
Rext
VDD
PIC16C55X
OSC1
Fosc/4
Internal Clock
VDD
1998 Microchip Technology Inc. Preliminary DS40143C-page 39
PIC16C55X
7.3 Reset
The PIC16C55X differentiates between various kinds
of reset:
a) Power-on reset (POR)
b) MCLR reset during normal operation
c) MCLR reset during SLEEP
d) WDT reset (normal operation)
e) WDT wake-up (SLEEP)
Some registers are not affected in any reset condition;
their status is unknown on POR and unchanged in an y
other reset. Most other registers are reset to a “reset
state” on Power-on reset, on MCLR or WDT reset and
on MCLR reset during SLEEP. The y are not aff ected by
a WDT wak e-up , since this is vie wed as the resumption
of normal operation. TO and PD bits are set or cleared
differently in different reset situations as indicated in
Table 7-4. These bits are used in software to determine
the nature of the reset. See Table 7-6 for a full descrip-
tion of reset states of all registers.
A simplified bloc k diagr am of the on-chip reset circuit is
shown in Figure 7-7.
The MCLR reset path has a noise filter to detect and
ignore small pulses. See Table 10-4 for pulse width
specification.
FIGURE 7-7: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
S
RQ
External
Reset
MCLR/
VDD
OSC1/
WDT
Module
VDD rise
detect
OST/PWRT
On-chip(1)
RC OSC
WDT
Time-out
Power-on Reset
OST
PWRT
Chip_Reset
10-bit Ripple-counter
Reset
Enable OST
Enable PWRT
SLEEP
See Table 7-3 for time-out situations.
Note 1: This is a separate oscillator from the RC oscillator of the CLKIN pin.
CLKIN
Pin
VPP Pin
10-bit Ripple-counter
PIC16C55X
DS40143C-page 40 Preliminary 1998 Microchip Technology Inc.
7.4 Power-on Reset (POR), Power-up
Timer (PWRT), Oscillator Start-up
Timer (OST)
7.4.1 POWER-ON RESET (POR)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected (in the range of 1.6 V – 1.8 V). To
take advantage of the POR, just tie the MCLR pin
through a resistor to VDD. This will eliminate external
RC components usually needed to create Power-on
Reset. A maximum rise time for VDD is required. See
Electrical Specifications for details.
The POR circuit does not produce internal reset when
VDD declines.
When the device starts normal operation (exits the
reset condition), de vice operating par ameters (voltage,
frequency, temperature, etc.) must be met to ensure
operation. If these conditions are not met, the device
must be held in reset until the operating conditions are
met.
For additional information, refer to Application Note
AN607 “Power-up Trouble Shooting”.
7.4.2 POWER-UP TIMER (PWRT)
The Power-up Timer provides a fixed 72 ms (nominal)
time-out on power-up only, from POR. The Power-up
Timer operates on an internal RC oscillator . The chip is
kept in reset as long as PWRT is active. The PWRT
delay allows the VDD to rise to an acceptable level. A
configuration bit, PWRTE can disable (if set) or enable
(if cleared or programmed) the Power-up Timer. The
Power-Up Time delay will vary from chip to chip and
due to VDD, temperature and process variation. See
DC parameters for details.
7.4.3 OSCILLATOR START-UP TIMER (OST)
The Oscillator Start-Up Timer (OST) provides a 1024
oscillator cycle (from OSC1 input) delay after the
PWRT delay is over. This ensures that the crystal
oscillator or resonator has started and stabilized.
The OST time-out is invoked only for XT, LP and HS
modes and only on power-on reset or wake-up from
SLEEP.
7.4.4 TIME-OUT SEQUENCE
On power-up, the time-out sequence is as follo ws: First
PWRT time-out is inv oked after POR has expired, then
OST is activated. The total time-out will var y based on
oscillator configuration and PWRTE bit status. For
example, in RC mode with PWRTE bit erased (PWRT
disabled), there will be no time-out at all. Figure 7-8,
Figure 7-9 and Figure 7-10 depict time-out sequences.
Since the time-outs occur from the POR pulse, if MCLR
is kept lo w long enough, the time-outs will expire. Then
bringing MCLR high will begin execution immediately
(see Figure 7-9). This is useful for testing purposes or
to synchronize more than one PIC16C55X de vice oper-
ating in parallel.
Table 7-5 shows the reset conditions for some special
registers, while Table 7-6 shows the reset conditions f or
all the registers.
1998 Microchip Technology Inc. Preliminary DS40143C-page 41
PIC16C55X
7.4.5 POWER CONTROL/STATUS REGISTER
(PCON)
Bit1 is POR (Power-on-reset). It is a ‘0’ on
power-on-reset and unaffected otherwise. The user
must write a ‘1’ to this bit following a power-on-reset.
On a subsequent reset if POR is ‘0’, it will indicate that
a power-on-reset must have occurred (VDD may have
gone too low).
TABLE 7-3: TIME-OUT IN VARIOUS SITUATIONS
TABLE 7-4: STATUS BITS AND THEIR SIGNIFICANCE
Oscillator Configuration Power-up Wake-up from
SLEEP
PWRTE = 0 PWRTE = 1
XT, HS, LP 72 ms + 1024 TOSC 1024 TOSC 1024 TOSC
RC 72 ms — —
POR TO PD
011Power-on-reset
00XIllegal, TO is set on POR
0X0Illegal, PD is set on POR
10uWDT Reset
100WDT Wake-up
1uuMCLR reset during normal operation
110MCLR reset during SLEEP
PIC16C55X
DS40143C-page 42 Preliminary 1998 Microchip Technology Inc.
TABLE 7-5: INITIALIZATION CONDITION FOR SPECIAL REGISTERS
TABLE 7-6: INITIALIZATION CONDITION FOR REGISTERS
Condition Program
Counter STATUS
Register PCON
Register
Power-on Reset 000h 0001 1xxx ---- --0-
MCLR reset during normal operation 000h 000u uuuu ---- --u-
MCLR reset during SLEEP 000h 0001 0uuu ---- --u-
WDT reset 000h 0000 uuuu ---- --u-
WDT Wake-up PC + 1 uuu0 0uuu ---- --u-
Interrupt Wake-up from SLEEP PC + 1(1) uuu1 0uuu ---- --u-
Legend: u = unchanged, x = unknown, - = unimplemented bit, reads as ‘0’.
Note 1: When the wake-up is due to an interrupt and global enable bit, GIE is set, the PC is loaded with the interrupt vector
(0004h) after execution of PC+1.
Register Address Power-on Reset
• MCLR Reset during
normal operation
• MCLR Reset during
SLEEP
• WDT Reset
• Wake up from SLEEP
through interrupt
• Wake up from SLEEP
through WDT time-out
W - xxxx xxxx uuuu uuuu uuuu uuuu
INDF 00h - - -
TMR0 01h xxxx xxxx uuuu uuuu uuuu uuuu
PCL 02h 0000 0000 0000 0000 PC + 1(2)
STATUS 03h 0001 1xxx 000q quuu(3) uuuq quuu(3)
FSR 04h xxxx xxxx uuuu uuuu uuuu uuuu
PORTA 05h ---x xxxx ---u uuuu ---u uuuu
PORTB 06h xxxx xxxx uuuu uuuu uuuu uuuu
PCLATH 0Ah ---0 0000 ---0 0000 ---u uuuu
INTCON 0Bh 0000 000x 0000 000u uuuu uuuu(1)
OPTION 81h 1111 1111 1111 1111 uuuu uuuu
TRISA 85h ---1 1111 ---1 1111 ---u uuuu
TRISB 86h 1111 1111 1111 1111 uuuu uuuu
PCON 8Eh ---- --0- ---- --u- ---- --u-
Legend: u = unchanged, x = unknown, - = unimplemented bit, reads as ‘0’,q = value depends on condition.
Note 1: One or more bits in INTCON will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt
vector (0004h).
3: See Table 7-5 for reset value for specific condition.
1998 Microchip Technology Inc. Preliminary DS40143C-page 43
PIC16C55X
FIGURE 7-8: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
FIGURE 7-9: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
FIGURE 7-10: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD): CASE 3
TPWRT
TOST
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
TPWRT
TOST
TPWRT
TOST
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
PIC16C55X
DS40143C-page 44 Preliminary 1998 Microchip Technology Inc.
FIGURE 7-11: EXTERNAL POWER-ON
RESET CIRCUIT (FOR SLOW
VDD POWER-UP)
Note 1: External power-on reset circuit is required
only if VDD power-up slope is too slow.
The diode D helps discharge the capaci-
tor quickly when VDD powers down.
2: < 40 kΩ is recommended to make sure
that voltage drop across R does not vio-
late the device’s electrical specification.
3: R1 = 100Ω to 1 kΩ will limit any current
flowing into MCLR from external capaci-
tor C in the e v ent of MCLR/VPP pin break-
down due to Electrostatic Discharge
(ESD) or Electrical Overstress (EOS).
C
R1
R
D
VDD
MCLR
PIC16C55X
VDD
1998 Microchip Technology Inc. Preliminary DS40143C-page 45
PIC16C55X
7.5 Interrupts
The PIC16C55X has 3 sources of interrupt:
• External interrupt RB0/INT
• TMR0 overflow interrupt
• PortB change interrupts (pins RB7:RB4)
The interrupt control register (INTCON) records
individual interrupt requests in flag bits. It also has
individual and global interrupt enable bits.
A global interrupt enable bit, GIE (INTCON<7>)
enables (if set) all un-masked interr upts or disables (if
cleared) all interrupts. Individual interrupts can be
disabled through their corresponding enable bits in
INTCON register. GIE is cleared on reset.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine as well as sets the GIE bit, which
re-enables RB0/INT interrupts.
The INT pin interrupt, the RB port change interrupt and
the TMR0 overflow interrupt flags are contained in the
INTCON register.
When an interrupt is responded to, the GIE is cleared
to disable any further interrupt, the return address is
pushed into the stack and the PC is loaded with 0004h.
Once in the interrupt service routine the source(s) of
the interrupt can be determined by polling the interrupt
flag bits. The interrupt flag bit(s) must be cleared in soft-
ware before re-enabling interrupts to avoid RB0/INT
recursive interrupts.
For external interrupt events, such as the INT pin or
PORTB change interrupt, the interrupt latency will be
three or four instruction cycles. The exact latency
depends when the interrupt ev ent occurs (Figure 7-13).
The latency is the same for one or two cycle
instructions. Once in the interrupt service routine the
source(s) of the interrupt can be determined by polling
the interrupt flag bits. The interrupt flag bit(s) must be
cleared in software before re-enabling interrupts to
avoid multiple interrupt requests. Individual interrupt
flag bits are set regardless of the status of their
corresponding mask bit or the GIE bit.
Note 1: Individual interrupt flag bits are set
regardless of the status of their
corresponding mask bit or the GIE bit.
2: When an instruction that clears the GIE
bit is executed, any interrupts that were
pending for execution in the next cycle
are ignored. The CPU will execute a
NOP in the cycle immediately following
the instruction which clears the GIE bit.
The interrupts which were ignored are
still pending to be serviced when the GIE
bit is set again.
FIGURE 7-12: INTERRUPT LOGIC
RBIF
RBIE
T0IF
T0IE
INTF
INTE
GIE
Wake-up
(If in SLEEP mode)
Interrupt
to CPU
PIC16C55X
DS40143C-page 46 Preliminary 1998 Microchip Technology Inc.
7.5.1 RB0/INT INTERRUPT
An e xternal interrupt on RB0/INT pin is edge triggered:
either rising if INTEDG bit (OPTION<6>) is set, or fall-
ing if INTEDG bit is clear. When a valid edge appears
on the RB0/INT pin, the INTF bit (INTCON<1>) is set.
This interrupt can be disabled by clearing the INTE
control bit (INTCON<4>). The INTF bit must be cleared
in software in the interrupt service routine before
re-enabling this interrupt. The RB0/INT interrupt can
wake-up the processor from SLEEP, if the INTE bit was
set prior to going into SLEEP. The status of the GIE bit
decides whether or not the processor branches to the
interrupt vector following wake-up. See Section 7.8 for
details on SLEEP and Figure 7-16 for timing of
wake-up from SLEEP through RB0/INT interrupt.
7.5.2 TMR0 INTERRUPT
An overflow (FFh → 00h) in the TMR0 register will
set the T0IF (INTCON<2>) bit. The interrupt can
be enabled/disabled by setting/clearing T0IE
(INTCON<5>) bit. For operation of the Timer0 module,
see Section 6.0.
7.5.3 PORTB INTERRUPT
An input change on PORTB <7:4> sets the RBIF
(INTCON<0>) bit. The interrupt can be enabled/dis-
abled by setting/clearing the RBIE (INTCON<4>) bit.
For operation of PORTB (Section 5.2).
Note: If a change on the I/O pin should occur
when the read operation is being executed
(start of the Q2 cycle), then the RBIF inter-
rupt flag may get set.
FIGURE 7-13: INT PIN INTERRUPT TIMING
Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
OSC1
CLKOUT
INT pin
INTF flag
(INTCON<1>)
GIE bit
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
fetched
Instruction
executed
Interrupt Latency
PC PC+1 PC+1 0004h 0005h
Inst (0004h) Inst (0005h)
Dummy Cycle
Inst (PC) Inst (PC+1)
Inst (PC-1) Inst (0004h)
Dummy Cycle
Inst (PC)
—
1
4
51
Note 1: INTF flag is sampled here (every Q1).
2: Interrupt latency = 3-4 Tcy where Tcy = instruction cycle time.
Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.
3: CLKOUT is available only in RC oscillator mode.
4: For minimum width of INT pulse, refer to AC specs.
5: INTF is enabled to be set anytime during the Q4-Q1 cycles.
2
3
1998 Microchip Technology Inc. Preliminary DS40143C-page 47
PIC16C55X
7.6 Context Saving During Interrupts
During an interrupt, only the return PC value is saved
on the stack. Typically, users may wish to sa v e k e y reg-
isters during an interr upt, e.g. W register and STATUS
register. This will have to be implemented in software.
Example 7-1 stores and restores the STATUS and W
registers. The user register, W_TEMP, must be defined
in both banks and must be defined at the same offset
from the bank base address (i.e., W_TEMP is defined
at 0x20 in Bank 0 and it must also be defined at 0xA0
in Bank 1). The user register, STATUS_TEMP, must be
defined in Bank 0. The Example 7-1:
• Stores the W register
• Stores the STATUS register in Bank 0
• Executes the ISR code
• Restores the STATUS (and bank select bit
register)
• Restores the W register
EXAMPLE 7-1: SAVING THE STATUS AND
W REGISTERS IN RAM
MOVWF W_TEMP ;copy W to temp register,
;could be in either bank
SWAPF STATUS,W ;swap status to be saved into W
BCF STATUS,RP0 ;change to bank 0 regardless
;of current bank
MOVWF STATUS_TEMP ;save status to bank 0
;register
:
: (ISR)
:
SWAPF STATUS_TEMP,W ;swap STATUS_TEMP register
;into W, sets bank to original
;state
MOVWF STATUS ;move W into STATUS register
SWAPF W_TEMP,F ;swap W_TEMP
SWAPF W_TEMP,W ;swap W_TEMP into W
7.7 Watchdog Timer (WDT)
The watchdog timer is a free running on-chip RC oscil-
lator which does not require any external components.
This RC oscillator is separate from the RC oscillator of
the CLKIN pin. That means that the WDT will run, e v en
if the clock on the OSC1 and OSC2 pins of the device
has been stopped, for example, by execution of a
SLEEP instruction. During normal operation, a WDT
time-out generates a device RESET. If the device is in
SLEEP mode, a WDT time-out causes the device to
wake-up and continue with normal operation. The WDT
can be permanently disabled by prog ramming the con-
figuration bit WDTE as clear (Section 7.1).
7.7.1 WDT PERIOD
The WDT has a nominal time-out period of 18 ms, (with
no prescaler). The time-out periods vary with tempera-
ture, VDD and process variations from part to part (see
DC specs). If longer time-out periods are desired, a
prescaler with a division ratio of up to 1:128 can be
assigned to the WDT under software control by writing
to the OPTION register. Thus, time-out periods up to
2.3 seconds can be realized.
The CLRWDT and SLEEP instr uctions clear the WDT
and the postscaler , if assigned to the WDT, and pre vent
it from timing out and generating a device RESET.
The TO bit in the STATUS register will be cleared upon
a Watchdog Timer time-out.
7.7.2 WDT PROGRAMMING CONSIDERATIONS
It should also be taken in account that under worst case
conditions (VDD = Min., Temperature = Max., max.
WDT prescaler) it may take several seconds before a
WDT time-out occurs.
PIC16C55X
DS40143C-page 48 Preliminary 1998 Microchip Technology Inc.
FIGURE 7-14: WATCHDOG TIMER BLOCK DIAGRAM
FIGURE 7-15: SUMMARY OF WATCHDOG TIMER REGISTERS
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR Value on all
other Resets
2007h Config. bits — + CP1 CP0 PWRTE WDTE FOSC1 FOSC0
81h OPTION RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
Legend: Shaded cells are not used by the Watchdog Timer.
— = Unimplemented location, read as ‘0’.
+ = Reserved for future use.
From TMR0 Clock Source
(Figure 6-6)
To TMR0 (Figure 6-6)
Postscaler
Watchdog
Timer
M
U
X
PSA
8 - to -1 MUX
PSA
WDT
Time-out
1
0
0
1
WDT
Enable Bit
PS<2:0>
•
•
Note: T0SE, T0CS, PSA, PS0-PS2 are bits in the OPTION register.
8
MUX
1998 Microchip Technology Inc. Preliminary DS40143C-page 49
PIC16C55X
7.8 Power-Down Mode (SLEEP)
The Power-down mode is entered by executing a
SLEEP instruction.
If enabled, the Watchdog Timer will be cleared but
keeps running, the PD bit in the STATUS register is
cleared, the TO bit is set, and the oscillator driver is
turned off. The I/O por ts maintain the status they had,
before SLEEP was executed (driving high, low, or
hi-impedance).
For lowest current consumption in this mode, all I/O
pins should be either at VDD, or VSS, with no exter nal
circuitry drawing current from the I/O pin . I/O pins that
are hi-impedance inputs should be pulled high or low
externally to avoid switching currents caused by float-
ing inputs. The T0CKI input should also be at VDD or
VSS for lowest current consumption. The contribution
from on chip pull-ups on P ORTB should be considered.
The MCLR pin must be at a logic high level (VIHMC).
7.8.1 WAKE-UP FROM SLEEP
The device can wake-up from SLEEP through one of
the following events:
1. External reset input on MCLR pin
2. Watchdog Timer Wake-up (if WDT was enab led)
3. Interrupt from RB0/INT pin or RB Port change
The first event will cause a device reset. The two latter
events are considered a continuation of program exe-
cution. The TO and PD bits in the STATUS register can
be used to determine the cause of device reset. PD
bit, which is set on power-up is cleared when SLEEP is
inv ok ed. T O bit is cleared if WDT Wake-up occurred.
When the SLEEP instruction is being executed, the
next instruction (PC + 1) is pre-fetched. For the device
to wak e-up through an interrupt e vent, the correspond-
ing interrupt enable bit must be set (enab led). Wake-up
is regardless of the state of the GIE bit. If the GIE bit is
clear (disabled), the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
set (enabled), the device executes the instr uction after
the SLEEP instr uction and then branches to the inter-
rupt address (0004h). In cases where the execution of
the instruction following SLEEP is not desirable, the
user should have an NOP after the SLEEP instruction.
The WDT is cleared when the device wakes-up from
sleep, regardless of the source of wake-up.
Note: It should be noted that a RESET generated
by a WDT time-out does not drive MCLR
pin low.
Note: If the global interrupts are disabled (GIE is
cleared), but any interrupt source has both
its interrupt enable bit and the correspond-
ing interrupt flag bits set, the device will
immediately wakeup from sleep. The sleep
instruction is completely executed.
FIGURE 7-16: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
CLKOUT(4)
INT pin
INTF flag
(INTCON<1>)
GIE bit
(INTCON<7>)
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
(Note 2)
Inst(PC + 2)
Inst(PC + 1)
Inst(0004h) Inst(0005h)
Inst(0004h)
Dummy cycle
PC + 2 0004h 0005h
Dummy cycle
TOST(2)
PC+2
Note 1: XT, HS or LP oscillator mode assumed.
2: TOST = 1024TOSC (drawing not to scale) This delay will not be there for RC osc mode.
3: GIE = '1' assumed. In this case after wake- up, the processor jumps to the interrupt routine. If GIE = '0', execution will continue in-line.
4: CLKOUT is not available in these osc modes, but shown here for timing reference.
PIC16C55X
DS40143C-page 50 Preliminary 1998 Microchip Technology Inc.
7.9 Code Protection
If the code protection bit(s) have not been
programmed, the on-chip program memory can be
read out for verification purposes.
7.10 ID Locations
Four memor y locations (2000h-2003h) are designated
as ID locations where the user can store checksum or
other code-identification numbers. These locations are
not accessible during normal execution but are
readable and writable during program/verify. Only the
least significant 4 bits of the ID locations are used.
Note: Microchip does not recommend code
protecting windowed devices.
7.11 In-Circuit Serial Programming™
The PIC16C55X microcontrollers can be serially
programmed while in the end application circuit. This is
simply done with two lines f or clock and data, and three
other lines for power, ground, and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices, and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
The device is placed into a program/verify mode by
holding the RB6 and RB7 pins low while raising the
MCLR (VPP) pin from VIL to VIHH (see programming
specification). RB6 becomes the programming clock
and RB7 becomes the programming data. Both RB6
and RB7 are Schmitt Trigger inputs in this mode.
After reset, to place the de vice into programming/v erify
mode, the program counter (PC) is at location 00h. A
6-bit command is then supplied to the device.
Depending on the command, 14-bits of program data
are then supplied to or from the device, depending if the
command was a load or a read. For complete details of
serial programming, please refer to the PIC16C6X/7X
Programming Specifications (Literature #DS30228).
A typical in-circuit serial programming connection is
shown in Figure 7-17.
FIGURE 7-17: TYPICAL IN-CIRCUIT SERIAL
PROGRAMMING
CONNECTION
External
Connector
Signals
To Normal
Connections
To Normal
Connections
PIC16C55X
VDD
VSS
MCLR/VPP
RB6
RB7
+5V
0V
VPP
CLK
Data I/O
VDD
1998 Microchip Technology Inc. Preliminary DS40143C-page 51
PIC16C55X
8.0 INSTRUCTION SET SUMMARY
Each PIC16C55X instruction is a 14-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 PIC16C55X instruc-
tion set summary in Table 8-2 lists byte-oriented,
bit-oriented, and literal and control operations.
Table 8-1 shows the opcode field descriptions.
For byte-oriented instructions, 'f' represents a file
register designator and 'd' represents a destination
designator. The file register designator specifies which
file register is to be used by the instruction.
The destination designator specifies where the result of
the operation is to be placed. If 'd' is zero, the result is
placed in the W register . If 'd' is one , the result is placed
in the file register specified in the instruction.
For bit-oriented instructions, 'b' represents a bit field
designator which selects the number of the bit aff ected
by the oper ation, while 'f' represents the number of the
file in which the bit is located.
For literal and control operations, 'k' represents an
eight or eleven bit constant or literal value.
TABLE 8-1: OPCODE FIELD
DESCRIPTIONS
Field Description
fRegister file address (0x00 to 0x7F)
WWorking register (accumulator)
bBit address within an 8-bit file register
kLiteral field, constant data or label
xDon't care location (= 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.
dDestination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1
label Label name
TOS Top of Stack
PC Program Counter
PCLATH Program Counter High Latch
GIE Global Interrupt Enable bit
WDT Watchdog Timer/Counter
TO Time-out bit
PD Power-down bit
dest Destination either the W register or the specified
register file location
[ ] Options
( ) Contents
→Assigned to
< > Register bit field
∈In the set of
i
talics
User defined term (font is courier)
The instruction set is highly orthogonal and is grouped
into three basic categories:
•Byte-oriented operations
•Bit-oriented operations
•Literal and control operations
All instructions are executed within one single
instruction cycle, unless a conditional test is true or the
program counter is changed as a result of an
instruction. In this case, the execution takes two
instruction cycles with the second cycle executed as a
NOP. 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.
Table 8-1 lists the instructions recognized by the
MPASM assembler.
Figure 8-1 shows the three general formats that the
instructions can have.
All examples use the following format to represent a
hexadecimal number:
0xhh
where h signifies a hexadecimal digit.
FIGURE 8-1: GENERAL FORMAT FOR
INSTRUCTIONS
Note: To maintain upward compatibility with
future PICmicro® products, do not use the
OPTION and TRIS instructions.
Byte-oriented file register operations
13 8 7 6 0
d = 0 for destination W
OPCODE d f (FILE #)
d = 1 for destination f
f = 7-bit file register address
Bit-oriented file register operations
13 10 9 7 6 0
OPCODE b (BIT #) f (FILE #)
b = 3-bit bit address
f = 7-bit file register address
Literal and control operations
13 8 7 0
OPCODE k (literal)
k = 8-bit immediate value
13 11 10 0
OPCODE k (literal)
k = 11-bit immediate value
General
CALL and GOTO instructions only
PIC16C55X
DS40143C-page 52 Preliminary 1998 Microchip Technology Inc.
TABLE 8-2: PIC16C55X INSTRUCTION SET
Mnemonic,
Operands Description Cycles 14-Bit Opcode Status
Affected Notes
MSb LSb
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF
ANDWF
CLRF
CLRW
COMF
DECF
DECFSZ
INCF
INCFSZ
IORWF
MOVF
MOVWF
NOP
RLF
RRF
SUBWF
SWAPF
XORWF
f, d
f, d
f
-
f, d
f, d
f, d
f, d
f, d
f, d
f, d
f
-
f, d
f, d
f, d
f, d
f, d
Add W and f
AND W with f
Clear f
Clear W
Complement f
Decrement f
Decrement f, Skip if 0
Increment f
Increment f, Skip if 0
Inclusive OR W with f
Move f
Move W to f
No Operation
Rotate Left f through Carry
Rotate Right f through Carry
Subtract W from f
Swap nibbles in f
Exclusive OR W with f
1
1
1
1
1
1
1(2)
1
1(2)
1
1
1
1
1
1
1
1
1
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
0111
0101
0001
0001
1001
0011
1011
1010
1111
0100
1000
0000
0000
1101
1100
0010
1110
0110
dfff
dfff
lfff
0000
dfff
dfff
dfff
dfff
dfff
dfff
dfff
lfff
0xx0
dfff
dfff
dfff
dfff
dfff
ffff
ffff
ffff
0011
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
0000
ffff
ffff
ffff
ffff
ffff
C,DC,Z
Z
Z
Z
Z
Z
Z
Z
Z
C
C
C,DC,Z
Z
1,2
1,2
2
1,2
1,2
1,2,3
1,2
1,2,3
1,2
1,2
1,2
1,2
1,2
1,2
1,2
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
BSF
BTFSC
BTFSS
f, b
f, b
f, b
f, b
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
1
1
1 (2)
1 (2)
01
01
01
01
00bb
01bb
10bb
11bb
bfff
bfff
bfff
bfff
ffff
ffff
ffff
ffff
1,2
1,2
3
3
LITERAL AND CONTROL OPERATIONS
ADDLW
ANDLW
CALL
CLRWDT
GOTO
IORLW
MOVLW
RETFIE
RETLW
RETURN
SLEEP
SUBLW
XORLW
k
k
k
-
k
k
k
-
k
-
-
k
k
Add literal and W
AND literal with W
Call subroutine
Clear Watchdog Timer
Go to address
Inclusive OR literal with W
Move literal to W
Return from interrupt
Return with literal in W
Return from Subroutine
Go into standby mode
Subtract W from literal
Exclusive OR literal with W
1
1
2
1
2
1
1
2
2
2
1
1
1
11
11
10
00
10
11
11
00
11
00
00
11
11
111x
1001
0kkk
0000
1kkk
1000
00xx
0000
01xx
0000
0000
110x
1010
kkkk
kkkk
kkkk
0110
kkkk
kkkk
kkkk
0000
kkkk
0000
0110
kkkk
kkkk
kkkk
kkkk
kkkk
0100
kkkk
kkkk
kkkk
1001
kkkk
1000
0011
kkkk
kkkk
C,DC,Z
Z
TO,PD
Z
TO,PD
C,DC,Z
Z
Note 1: When an I/O register is modified as a function of itself ( e.g., MOVF PORTB, 1), 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 ex ecuted on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned
to the Timer0 Module.
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.
1998 Microchip Technology Inc. Preliminary DS40143C-page 53
PIC16C55X
8.1 Instruction Descriptions
ADDLW Add Literal and W
Syntax: [
label
] ADDLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) + k → (W)
Status Affected: C, DC, Z
Encoding: 11 111x kkkk kkkk
Description: The contents of the W register are
added to the eight bit literal 'k' and the
result is placed in the W register.
Words: 1
Cycles: 1
Example ADDLW 0x15
Before Instruction
W = 0x10
After Instruction
W = 0x25
ADDWF Add W and f
Syntax: [
label
] ADDWF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (W) + (f) → (dest)
Status Affected: C, DC, Z
Encoding: 00 0111 dfff ffff
Description: Add the contents of the W register
with register 'f'. If 'd' is 0 the result is
stored in the W register. If 'd' is 1 the
result is stored back in register 'f'.
Words: 1
Cycles: 1
Example ADDWF FSR, 0
Before Instruction
W = 0x17
FSR = 0xC2
After Instruction
W = 0xD9
FSR = 0xC2
ANDLW AND Literal with W
Syntax: [
label
] ANDLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .AND. (k) → (W)
Status Affected: Z
Encoding: 11 1001 kkkk kkkk
Description: The contents of W register are
AND’ed with the eight bit literal 'k'. The
result is placed in the W register.
Words: 1
Cycles: 1
Example ANDLW 0x5F
Before Instruction
W = 0xA3
After Instruction
W = 0x03
ANDWF AND W with f
Syntax: [
label
] ANDWF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (W) .AND. (f) → (dest)
Status Affected: Z
Encoding: 00 0101 dfff ffff
Description: AND the W register with register 'f'. If
'd' is 0 the result is stored in the W
register. If 'd' is 1 the result is stored
back in register 'f'.
Words: 1
Cycles: 1
Example ANDWF FSR, 1
Before Instruction
W = 0x17
FSR = 0xC2
After Instruction
W = 0x17
FSR = 0x02
PIC16C55X
DS40143C-page 54 Preliminary 1998 Microchip Technology Inc.
BCF Bit Clear f
Syntax: [
label
] BCF f,b
Operands: 0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operation: 0 → (f<b>)
Status Affected: None
Encoding: 01 00bb bfff ffff
Description: Bit 'b' in register 'f' is cleared.
Words: 1
Cycles: 1
Example BCF FLAG_REG, 7
Before Instruction
FLAG_REG = 0xC7
After Instruction
FLAG_REG = 0x47
BSF Bit Set f
Syntax: [
label
] BSF f,b
Operands: 0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operation: 1 → (f<b>)
Status Affected: None
Encoding: 01 01bb bfff ffff
Description: Bit 'b' in register 'f' is set.
Words: 1
Cycles: 1
Example BSF FLAG_REG, 7
Before Instruction
FLAG_REG = 0x0A
After Instruction
FLAG_REG = 0x8A
BTFSC Bit Test, Skip if Clear
Syntax: [
label
] BTFSC f,b
Operands: 0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operation: skip if (f<b>) = 0
Status Affected: None
Encoding: 01 10bb bfff ffff
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
two-cycle instruction.
Words: 1
Cycles: 1(2)
Example HERE
FALSE
TRUE
BTFSC
GOTO
•
•
•
FLAG,1
PROCESS_CODE
Before Instruction
PC = address HERE
After Instruction
if FLAG<1> = 0,
PC = address TRUE
if FLAG<1>=1,
PC = address FALSE
1998 Microchip Technology Inc. Preliminary DS40143C-page 55
PIC16C55X
BTFSS Bit Test f, Skip if Set
Syntax: [
label
] BTFSS f,b
Operands: 0 ≤ f ≤ 127
0 ≤ b < 7
Operation: skip if (f<b>) = 1
Status Affected: None
Encoding: 01 11bb bfff 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
two-cycle instruction.
Words: 1
Cycles: 1(2)
Example HERE
FALSE
TRUE
BTFSS
GOTO
•
•
•
FLAG,1
PROCESS_CODE
Before Instruction
PC = address HERE
After Instruction
if FLAG<1> = 0,
PC = address FALSE
if FLAG<1> = 1,
PC = address TRUE
CALL Call Subroutine
Syntax: [
label
] CALL k
Operands: 0 ≤ k ≤ 2047
Operation: (PC)+ 1→ TOS,
k → PC<10:0>,
(PCLATH<4:3>) → PC<12:11>
Status Affected: None
Encoding: 10 0kkk kkkk kkkk
Description: Call Subroutine. First, return address
(PC+1) is pushed onto the stack. The
eleven bit immediate address is loaded
into PC bits <10:0>. The upper bits of
the PC are loaded from PCLATH.
CALL is a two-cycle instruction.
Words: 1
Cycles: 2
Example HERE CALL THERE
Before Instruction
PC = Address HERE
After Instruction
PC = Address THERE
TOS = Address HERE+1
CLRF Clear f
Syntax: [
label
] CLRF f
Operands: 0 ≤ f ≤ 127
Operation: 00h → (f)
1 → Z
Status Affected: Z
Encoding: 00 0001 1fff ffff
Description: The contents of register 'f' are cleared
and the Z bit is set.
Words: 1
Cycles: 1
Example CLRF FLAG_REG
Before Instruction
FLAG_REG = 0x5A
After Instruction
FLAG_REG = 0x00
Z = 1
CLRW Clear W
Syntax: [
label
] CLRW
Operands: None
Operation: 00h → (W)
1 → Z
Status Affected: Z
Encoding: 00 0001 0000 0011
Description: W register is cleared. Zero bit (Z) is
set.
Words: 1
Cycles: 1
Example CLRW
Before Instruction
W = 0x5A
After Instruction
W = 0x00
Z = 1
PIC16C55X
DS40143C-page 56 Preliminary 1998 Microchip Technology Inc.
CLRWDT Clear Watchdog Timer
Syntax: [
label
] CLRWDT
Operands: None
Operation: 00h → WDT
0 → WDT prescaler,
1 → TO
1 → PD
Status Affected: TO, PD
Encoding: 00 0000 0110 0100
Description: CLRWDT instruction resets the
Watchdog Timer. It also resets the
prescaler of the WDT. Status bits TO
and PD are set.
Words: 1
Cycles: 1
Example CLRWDT
Before Instruction
WDT counter = ?
After Instruction
WDT counter = 0x00
WDT prescaler= 0
TO = 1
PD = 1
COMF Complement f
Syntax: [
label
] COMF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) → (dest)
Status Affected: Z
Encoding: 00 1001 dfff 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'.
Words: 1
Cycles: 1
Example COMF REG1,0
Before Instruction
REG1 = 0x13
After Instruction
REG1 = 0x13
W = 0xEC
DECF Decrement f
Syntax: [
label
] DECF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) - 1 → (dest)
Status Affected: Z
Encoding: 00 0011 dfff ffff
Description: Decrement register 'f'. If 'd' is 0 the
result is stored in the W register. If 'd'
is 1 the result is stored back in register
'f'.
Words: 1
Cycles: 1
Example DECF CNT, 1
Before Instruction
CNT = 0x01
Z = 0
After Instruction
CNT = 0x00
Z = 1
DECFSZ Decrement f, Skip if 0
Syntax: [
label
] DECFSZ f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) - 1 → (dest); skip if result = 0
Status Affected: None
Encoding: 00 1011 dfff ffff
Description: The contents of register 'f' are
decremented. If 'd' is 0 the result is
placed in the W register. If 'd' is 1 the
result is placed back in register 'f'.
If the result is 0, the next instruction,
which is already fetched, is discarded. A
NOP is executed instead making it a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Example HERE DECFSZ CNT, 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+1
1998 Microchip Technology Inc. Preliminary DS40143C-page 57
PIC16C55X
GOTO Unconditional Branch
Syntax: [
label
] GOTO k
Operands: 0 ≤ k ≤ 2047
Operation: k → PC<10:0>
PCLATH<4:3> → PC<12:11>
Status Affected: None
Encoding: 10 1kkk kkkk kkkk
Description: GOTO is an unconditional branch. The
eleven bit immediate value is loaded
into PC bits <10:0>. The upper bits of
PC are loaded from PCLATH<4:3>.
GOTO is a two-cycle instruction.
Words: 1
Cycles: 2
Example GOTO THERE
After Instruction
PC = Address THERE
INCF Increment f
Syntax: [
label
] INCF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) + 1 → (dest)
Status Affected: Z
Encoding: 00 1010 dfff ffff
Description: The contents of register 'f' are
incremented. If 'd' is 0 the result is
placed in the W register. If 'd' is 1 the
result is placed back in register 'f'.
Words: 1
Cycles: 1
Example INCF CNT, 1
Before Instruction
CNT = 0xFF
Z = 0
After Instruction
CNT = 0x00
Z = 1
INCFSZ Increment f, Skip if 0
Syntax: [
label
] INCFSZ f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) + 1 → (dest), skip if result = 0
Status Affected: None
Encoding: 00 1111 dfff ffff
Description: The contents of register 'f' are
incremented. If 'd' is 0 the result is
placed in the W register. If 'd' is 1 the
result is placed back in register 'f'.
If the result is 0, the next instruction,
which is already fetched, is discarded.
A NOP is executed instead making it
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Example HERE INCFSZ CNT, 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 +1
IORLW Inclusive OR Literal with W
Syntax: [
label
] IORLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .OR. k → (W)
Status Affected: Z
Encoding: 11 1000 kkkk kkkk
Description: The contents of the W register is
OR’ed with the eight bit literal 'k'. The
result is placed in the W register.
Words: 1
Cycles: 1
Example IORLW 0x35
Before Instruction
W = 0x9A
After Instruction
W = 0xBF
Z = 1
PIC16C55X
DS40143C-page 58 Preliminary 1998 Microchip Technology Inc.
IORWF Inclusive OR W with f
Syntax: [
label
] IORWF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (W) .OR. (f) → (dest)
Status Affected: Z
Encoding: 00 0100 dfff ffff
Description: Inclusive OR the W register with
register 'f'. If 'd' is 0 the result is placed
in the W register. If 'd' is 1 the result is
placed back in register 'f'.
Words: 1
Cycles: 1
Example IORWF RESULT, 0
Before Instruction
RESULT = 0x13
W = 0x91
After Instruction
RESULT = 0x13
W = 0x93
Z = 1
MOVLW Move Literal to W
Syntax: [
label
] MOVLW k
Operands: 0 ≤ k ≤ 255
Operation: k → (W)
Status Affected: None
Encoding: 11 00xx kkkk kkkk
Description: The eight bit literal 'k' is loaded into W
register. The don’t cares will assemble
as 0’s.
Words: 1
Cycles: 1
Example MOVLW 0x5A
After Instruction
W = 0x5A
MOVF Move f
Syntax: [
label
] MOVF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) → (dest)
Status Affected: Z
Encoding: 00 1000 dfff ffff
Description: The contents of register f is moved to
a destination dependant upon the
status of d. If d = 0, destination is W
register. If d = 1, the destination is file
register f itself. d = 1 is useful to test a
file register since status flag Z is
affected.
Words: 1
Cycles: 1
Example MOVF FSR, 0
After Instruction
W = value in FSR register
Z = 1
MOVWF Move W to f
Syntax: [
label
] MOVWF f
Operands: 0 ≤ f ≤ 127
Operation: (W) → (f)
Status Affected: None
Encoding: 00 0000 1fff ffff
Description: Move data from W register to register
'f'.
Words: 1
Cycles: 1
Example MOVWF OPTION
Before Instruction
OPTION = 0xFF
W = 0x4F
After Instruction
OPTION = 0x4F
W = 0x4F
1998 Microchip Technology Inc. Preliminary DS40143C-page 59
PIC16C55X
NOP No Operation
Syntax: [
label
] NOP
Operands: None
Operation: No operation
Status Affected: None
Encoding: 00 0000 0xx0 0000
Description: No operation.
Words: 1
Cycles: 1
Example NOP
OPTION Load Option Register
Syntax: [
label
] OPTION
Operands: None
Operation: (W) → OPTION
Status Affected: None
Encoding: 00 0000 0110 0010
Description: The contents of the W register are
loaded in the OPTION register. This
instruction is supported for code
compatibility with PIC16C5X products.
Since OPTION is a readable/writable
register, the user can directly
address it.
Words: 1
Cycles: 1
Example To maintain upward compatibility
with future PICmicro™ products,
do not use this instruction.
RETFIE Return from Interrupt
Syntax: [
label
] RETFIE
Operands: None
Operation: TOS → PC,
1 → GIE
Status Affected: None
Encoding: 00 0000 0000 1001
Description: Return from Interrupt. Stac k is POPed
and Top of Stack (TOS) is loaded in
the PC. Interrupts are enabled by
setting Global Interrupt Enable bit,
GIE (INTCON<7>). This is a two-cycle
instruction.
Words: 1
Cycles: 2
Example RETFIE
After Interrupt
PC = TOS
GIE = 1
RETLW Return with Literal in W
Syntax: [
label
] RETLW k
Operands: 0 ≤ k ≤ 255
Operation: k → (W);
TOS → PC
Status Affected: None
Encoding: 11 01xx kkkk kkkk
Description: The W register is loaded with the eight
bit literal 'k'. The program counter is
loaded from the top of the stack (the
return address). This is a two-cycle
instruction.
Words: 1
Cycles: 2
Example
TABLE
CALL TABLE ;W contains table
;offset value
• ;W now has table
value
•
•
ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2 ;
•
•
•
RETLW kn ; End of table
Before Instruction
W = 0x07
After Instruction
W = value of k8
PIC16C55X
DS40143C-page 60 Preliminary 1998 Microchip Technology Inc.
RETURN Return from Subroutine
Syntax: [
label
] RETURN
Operands: None
Operation: TOS → PC
Status Affected: None
Encoding: 00 0000 0000 1000
Description: Return from subroutine. The stack is
POPed and the top of the stack (T OS)
is loaded into the program counter.
This is a two cycle instruction.
Words: 1
Cycles: 2
Example RETURN
After Interrupt
PC = TOS
RLF Rotate Left f through Carry
Syntax: [
label
] RLF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: See description below
Status Affected: C
Encoding: 00 1101 dfff 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
the W register. If 'd' is 1 the result is
stored back in register 'f'.
Words: 1
Cycles: 1
Example RLF REG1,0
Before Instruction
REG1 = 1110 0110
C= 0
After Instruction
REG1 = 1110 0110
W= 1100 1100
C= 1
Register fC
RRF Rotate Right f through Carry
Syntax: [
label
] RRF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: See description below
Status Affected: C
Encoding: 00 1100 dfff 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
the W register. If 'd' is 1 the result is
placed back in register 'f'.
Words: 1
Cycles: 1
Example RRF REG1,0
Before Instruction
REG1 = 1110 0110
C= 0
After Instruction
REG1 = 1110 0110
W= 0111 0011
C= 0
SLEEP
Syntax: [
label
] SLEEP
Operands: None
Operation: 00h → WDT,
0 → WDT prescaler,
1 → TO,
0 → PD
Status Affected: TO, PD
Encoding: 00 0000 0110 0011
Description: The power-down status bit, PD is
cleared. Time-out status bit, TO is
set. Watchdog Timer and its
prescaler are cleared.
The processor is put into SLEEP
mode with the oscillator stopped.
See Section 7.8 for more details.
Words: 1
Cycles: 1
Example: SLEEP
Register fC
1998 Microchip Technology Inc. Preliminary DS40143C-page 61
PIC16C55X
SUBLW Subtract W from Literal
Syntax: [
label
] SUBLW k
Operands: 0 ≤ k ≤ 255
Operation: k - (W) → (W)
Status
Affected: C, DC, Z
Encoding: 11 110x kkkk kkkk
Description: The W register is subtracted (2’s com-
plement method) from the eight bit literal
'k'. The result is placed in the W register.
Words: 1
Cycles: 1
Example 1: SUBLW 0x02
Before Instruction
W = 1
C = ?
After Instruction
W = 1
C = 1; result is posi-
tive
Example 2: Before Instruction
W = 2
C = ?
After Instruction
W = 0
C = 1; result is zero
Example 3: Before Instruction
W = 3
C = ?
After Instruction
W = 0xFF
C = 0; result is nega-
tive
SUBWF Subtract W from f
Syntax: [
label
] SUBWF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f) - (W) → (dest)
Status
Affected: C, DC, Z
Encoding: 00 0010 dfff ffff
Description: Subtract (2’s complement method)
W register from register 'f'. If 'd' is 0 the
result is stored in the W register. If 'd' is 1
the result is stored back in register 'f'.
Words: 1
Cycles: 1
Example 1: SUBWF REG1,1
Before Instruction
REG1 = 3
W = 2
C = ?
After Instruction
REG1 = 1
W = 2
C = 1; result is positive
Example 2: Before Instruction
REG1 = 2
W = 2
C = ?
After Instruction
REG1 = 0
W = 2
C = 1; result is zero
Example 3: Before Instruction
REG1 = 1
W = 2
C = ?
After Instruction
REG1 = 0xFF
W = 2
C = 0; result is negative
PIC16C55X
DS40143C-page 62 Preliminary 1998 Microchip Technology Inc.
SWAPF Swap Nibbles in f
Syntax: [
label
] SWAPF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (f<3:0>) → (dest<7:4>),
(f<7:4>) → (dest<3:0>)
Status Affected: None
Encoding: 00 1110 dfff ffff
Description: The upper and lower nibbles of
register 'f' are exchanged. If 'd' is 0
the result is placed in W register. If 'd'
is 1 the result is placed in register 'f'.
Words: 1
Cycles: 1
Example SWAPF REG, 0
Before Instruction
REG1 = 0xA5
After Instruction
REG1 = 0xA5
W = 0x5A
TRIS Load TRIS Register
Syntax: [
label
] TRIS f
Operands: 5 ≤ f ≤ 7
Operation: (W) → TRIS register f;
Status Affected: None
Encoding: 00 0000 0110 0fff
Description: The instruction is supported for code
compatibility with the PIC16C5X
products. Since TRIS registers are
readable and writable, the user can
directly address them.
Words: 1
Cycles: 1
Example To maintain upward compatibility
with future PICmicro™ products,
do not use this instruction.
XORLW Exclusive OR Literal with W
Syntax: [
label
] XORLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .XOR. k → (W)
Status Affected: Z
Encoding: 11 1010 kkkk kkkk
Description: The contents of the W register are
XOR’ed with the eight bit literal 'k'.
The result is placed in the
W register.
Words: 1
Cycles: 1
Example: XORLW 0xAF
Before Instruction
W = 0xB5
After Instruction
W = 0x1A
XORWF Exclusive OR W with f
Syntax: [
label
] XORWF f,d
Operands: 0 ≤ f ≤ 127
d ∈ [0,1]
Operation: (W) .XOR. (f) → (dest)
Status Affected: Z
Encoding: 00 0110 dfff ffff
Description: Exclusive OR the contents of the
W register with register 'f'. If 'd' is 0 the
result is stored in the W register. If 'd'
is 1 the result is stored back in register
'f'.
Words: 1
Cycles: 1
Example XORWF REG 1
Before Instruction
REG = 0xAF
W = 0xB5
After Instruction
REG = 0x1A
W = 0xB5
1998 Microchip Technology Inc. Preliminary DS40143C-page 63
PIC16C55X
9.0 DEVELOPMENT SUPPORT
9.1 Development Tools
The PICmicrο microcontrollers are supported with a
full range of hardware and softw are de velopment tools:
• MPLAB™-ICE Real-Time In-Circuit Emulator
• ICEPIC Low-Cost PIC16C5X and PIC16CXXX
In-Circuit Emulator
• PRO MATE II Universal Programmer
• PICSTART Plus Entry-Level Prototype
Programmer
• SIMICE
• PICDEM-1 Low-Cost Demonstration Board
• PICDEM-2 Low-Cost Demonstration Board
• PICDEM-3 Low-Cost Demonstration Board
• MPASM Assembler
• MPLAB SIM Software Simulator
• MPLAB-C17 (C Compiler)
•Fuzzy Logic De velopment System
(
fuzzy
TECH−MP)
• KEELOQ® Evaluation Kits and Programmer
9.2 MPLAB-ICE: High Performance
Universal In-Circuit Emulator with
MPLAB IDE
The MPLAB-ICE Universal In-Circuit Emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for
PICmicro microcontrollers (MCUs). MPLAB-ICE is sup-
plied with the MPLAB Integrated De velopment En viron-
ment (IDE), which allows editing, “make” and
download, and source debugging from a single envi-
ronment.
Interchangeable processor modules allow the system
to be easily reconfigured for emulation of different pro-
cessors. The universal architecture of the MPLAB-ICE
allows expansion to support all new Microchip micro-
controllers.
The MPLAB-ICE Emulator System has been designed
as a real-time emulation system with advanced fea-
tures that are generally found on more expensive
development tools . The PC compatible 386 (and higher)
machine platform and Microsoft Windows 3.x or
Windows 95 environment were chosen to best make
these features available to you, the end user.
MPLAB-ICE is available in two versions.
MPLAB-ICE 1000 is a basic, lo w-cost emulator system
with simple trace capabilities. It shares processor mod-
ules with the MPLAB-ICE 2000. This is a full-featured
emulator system with enhanced trace , trigger, and data
monitoring features. Both systems will operate across
the entire operating speed reange of the PICmicro
MCU.
9.3 ICEPIC: Low-Cost PICmicro
In-Circuit Emulator
ICEPIC is a low-cost in-circuit emulator solution for the
Microchip PIC12CXXX, PIC16C5X and PIC16CXXX
families of 8-bit OTP microcontrollers.
ICEPIC is designed to operate on PC-compatible
machines ranging from 386 through Pentium based
machines under Windows 3.x, Windows 95, or Win-
dows NT environment. ICEPIC features real time,
non-intrusive emulation.
9.4 PRO MATE II: Universal Programmer
The PRO MATE II Universal Programmer is a full-fea-
tured programmer capable of operating in stand-alone
mode as well as PC-hosted mode. PRO MATE II is CE
compliant.
The PRO MATE II has programmable VDD and VPP
supplies which allows it to verify programmed memory
at VDD min and VDD max for maximum reliability. It has
an LCD display for displaying error messages, keys to
enter commands and a modular detachable socket
assembly to support various package types. In stand-
alone mode the PRO MATE II can read, verify or pro-
gram PIC12CXXX, PIC14C000, PIC16C5X,
PIC16CXXX and PIC17CXX devices. It can also set
configuration and code-protect bits in this mode.
9.5 PICSTART Plus Entry Level
Development System
The PICSTART programmer is an easy-to-use,
low-cost prototype programmer. It connects to the PC
via one of the COM (RS-232) ports. MPLAB Integrated
Development Environment software makes using the
programmer simple and efficient. PICSTART Plus is
not recommended for production programming.
PICSTART Plus supports all PIC12CXXX, PIC14C000,
PIC16C5X, PIC16CXXX and PIC17CXX devices with
up to 40 pins. Larger pin count devices such as the
PIC16C923, PIC16C924 and PIC17C756 ma y be sup-
ported with an adapter socket. PICSTART Plus is CE
compliant.
PIC16C55X
DS40143C-page 64 Preliminary 1998 Microchip Technology Inc.
9.6 SIMICE Entry-Level Hardware
Simulator
SIMICE is an entry-level hardware development sys-
tem designed to operate in a PC-based environment
with Microchip’s simulator MPLAB™-SIM. Both SIM-
ICE and MPLAB-SIM run under Microchip Technol-
ogy’s MPLAB Integrated Development Environment
(IDE) software . Specifically, SIMICE provides hardware
simulation for Microchip’s PIC12C5XX, PIC12CE5XX,
and PIC16C5X f amilies of PICmicro 8-bit microcontrol-
lers. SIMICE works in conjunction with MPLAB-SIM to
provide non-real-time I/O port emulation. SIMICE
enables a developer to run simulator code for driving
the target system. In addition, the target system can
provide input to the simulator code. This capability
allows for simple and interactive debugging without
having to manually generate MPLAB-SIM stimulus
files. SIMICE is a valuable debugging tool for
entry-level system development.
9.7 PICDEM-1 Low-Cost PICmicro
Demonstration Board
The PICDEM-1 is a simple board which demonstrates
the capabilities of several of Microchip’s microcontrol-
lers. The microcontrollers supported are: PIC16C5X
(PIC16C54 to PIC16C58A), PIC16C61, PIC16C62X,
PIC16C71, PIC16C8X, PIC17C42, PIC17C43 and
PIC17C44. All necessary hardware and software is
included to run basic demo programs. The users can
program the sample microcontrollers provided with
the PICDEM-1 board, on a PRO MATE II or
PICSTART-Plus programmer, and easily test firm-
ware. The user can also connect the PICDEM-1
board to the MPLAB-ICE emulator and do wnload the
firmware to the emulator for testing. Additional proto-
type area is available for the user to build some addi-
tional hardware and connect it to the microcontroller
socket(s). Some of the features include an RS-232
interface, a potentiometer for simulated analog input,
push-button switches and eight LEDs connected to
PORTB.
9.8 PICDEM-2 Low-Cost PIC16CXX
Demonstration Board
The PICDEM-2 is a simple demonstration board that
supports the PIC16C62, PIC16C64, PIC16C65,
PIC16C73 and PIC16C74 microcontrollers. All the
necessary hardware and software is included to
run the basic demonstration programs. The user
can program the sample microcontrollers provided
with the PICDEM-2 board, on a PRO MATE II pro-
grammer or PICSTART-Plus, and easily test firmware .
The MPLAB-ICE emulator may also be used with the
PICDEM-2 board to test firmware. Additional prototype
area has been provided to the user for adding addi-
tional hardware and connecting it to the microcontroller
socket(s). Some of the features include a RS-232 inter-
face, push-button switches, a potentiometer for simu-
lated analog input, a Serial EEPROM to demonstrate
usage of the I2C b us and separate headers f or connec-
tion to an LCD module and a keypad.
9.9 PICDEM-3 Low-Cost PIC16CXXX
Demonstration Board
The PICDEM-3 is a simple demonstration board that
supports the PIC16C923 and PIC16C924 in the PLCC
package. It will also support future 44-pin PLCC
microcontrollers with a LCD Module. All the neces-
sary hardware and software is included to r un the
basic demonstration programs. The user can pro-
gram the sample microcontrollers provided with
the PICDEM-3 board, on a PRO MATE II program-
mer or PICSTART Plus with an adapter socket, and
easily test firmware. The MPLAB-ICE emulator may
also be used with the PICDEM-3 board to test firm-
ware. Additional prototype area has been provided to
the user for adding hardware and connecting it to the
microcontroller sock et(s). Some of the f eatures include
an RS-232 interface, push-button switches, a potenti-
ometer for simulated analog input, a thermistor and
separate headers for connection to an external LCD
module and a ke ypad. Also provided on the PICDEM-3
board is an LCD panel, with 4 commons and 12 seg-
ments, that is capable of displaying time, temperature
and da y of the w eek. The PICDEM-3 provides an addi-
tional RS-232 interface and Windows 3.1 software for
showing the demultiple xed LCD signals on a PC . A sim-
ple serial interface allows the user to construct a hard-
ware demultiplexer for the LCD signals.
1998 Microchip Technology Inc. Preliminary DS40143C-page 65
PIC16C55X
9.10 MPLAB Integrated Development
Environment Software
The MPLAB IDE Software brings an ease of software
development previously unseen in the 8-bit microcon-
troller market. MPLAB is a windows based application
which contains:
• A full featured editor
• Three operating modes
- editor
- emulator
- simulator
• A project manager
• Customizable tool bar and key mapping
• A status bar with project information
• Extensive on-line help
MPLAB allows you to:
• Edit your source files (either assembly or ‘C’)
• One touch assemble (or compile) and download
to PICmicro tools (automatically updates all
project information)
• Debug using:
- source files
- absolute listing file
The ability to use MPLAB with Microchip’s simulator
allows a consistent platform and the ability to easily
switch from the low cost simulator to the full featured
emulator with minimal retraining due to development
tools.
9.11 Assembler (MPASM)
The MPASM Universal Macro Assembler is a
PC-hosted symbolic assembler. It supports all micro-
controller series including the PIC12C5XX, PIC14000,
PIC16C5X, PIC16CXXX, and PIC17CXX families.
MPASM offers full featured Macro capabilities, condi-
tional assembly, and sev eral source and listing f ormats.
It generates various object code formats to support
Microchip's development tools as well as third party
programmers.
MPASM allows full symbolic debugging from
MPLAB-ICE, Microchip’s Universal Emulator System.
MPASM has the follo wing features to assist in dev elop-
ing software for specific use applications.
• Provides translation of Assembler source code to
object code for all Microchip microcontrollers.
• Macro assembly capability.
• Produces all the files (Object, Listing, Symbol, and
special) required for symbolic debug with
Microchip’s emulator systems.
• Supports Hex (default), Decimal and Octal source
and listing formats.
MPASM provides a rich directive language to support
programming of the PICmicro. Directives are helpful in
making the development of y our assemble source code
shorter and more maintainable.
9.12 Software Simulator (MPLAB-SIM)
The MPLAB-SIM Software Simulator allows code
development in a PC host environment. It allows the
user to simulate the PICmicro series microcontrollers
on an instruction level. On any given instruction, the
user may examine or modify any of the data areas or
provide external stimulus to any of the pins. The
input/output radix can be set by the user and the exe-
cution can be performed in; single step, execute until
break, or in a trace mode.
MPLAB-SIM fully supports symbolic debugging using
MPLAB-C17 and MPASM. The Software Simulator
offers the low cost fle xibility to de v elop and debug code
outside of the laboratory environment making it an
excellent multi-project software development tool.
9.13 MPLAB-C17 Compiler
The MPLAB-C17 Code Development System is a
complete ANSI ‘C’ compiler and integrated develop-
ment environment f or Microchip’ s PIC17CXXX family of
microcontrollers. The compiler provides powerful inte-
gration capabilities and ease of use not found with
other compilers.
For easier source level debugging, the compiler pro-
vides symbol information that is compatible with the
MPLAB IDE memory display.
9.14 Fuzzy Logic Development System
(
fuzzy
TECH-MP)
fuzzy
TECH-MP fuzzy logic development tool is avail-
able in two versions - a low cost introductory version,
MP Explorer, for designers to gain a comprehensive
working knowledge of fuzzy logic system design; and a
full-featured version,
fuzzy
TECH-MP, Edition for imple-
menting more complex systems.
Both versions include Microchip’s
fuzzy
LAB demon-
stration board f or hands-on experience with fuzzy logic
systems implementation.
9.15 SEEVAL Evaluation and
Programming System
The SEEVAL SEEPROM Designer’s Kit supports all
Microchip 2-wire and 3-wire Serial EEPROMs. The kit
includes everything necessar y to read, write, erase or
program special features of any Microchip SEEPROM
product including Smart Serials and secure serials.
The Total Endurance Disk is included to aid in
trade-off analysis and reliability calculations. The total
kit can significantly reduce time-to-market and result in
an optimized system.
PIC16C55X
DS40143C-page 66 Preliminary 1998 Microchip Technology Inc.
9.16 KEELOQ Evaluation and
Programming Tools
KEELOQ evaluation and programming tools support
Microchips HCS Secure Data Products. The HCS e v al-
uation kit includes an LCD display to show changing
codes, a decoder to decode transmissions, and a pro-
gramming interface to program test transmitters.
1998 Microchip Technology Inc. Preliminary DS40143C-page 67
PIC16C55X
TABLE 9-1: DEVELOPMENT TOOLS FROM MICROCHIP
PIC12C5XX PIC14000 PIC16C5X PIC16CXXX PIC16C6X PIC16C7XX PIC16C8X PIC16C9XX PIC17C4X PIC17C7XX 24CXX
25CXX
93CXX
HCS200
HCS300
HCS301
Emulator Products
MPLAB™-ICE üüüüüüüüüü
ICEPIC Low-Cost
In-Circuit Emulator üüüüüü
Software Tools
MPLAB
Integrated
Development
Environment
üüüüüüüüüü
MPLAB C17*
Compiler ü ü
fuzzy
TECH-MP
Explorer/Edition
Fuzzy Logic
Dev. Tool
üüüüüüüüü
Total Endurance
Software Model ü
Programmers
PICSTARTPlus
Low-Cost
Universal Dev. Kit üüüüüüüüüü
PRO MATE II
Universal
Programmer üüüüüüüüüüüü
KEELOQ
Programmer ü
Demo Boards
SEEVAL
Designers Kit ü
SIMICE ü ü
PICDEM-14A ü
PICDEM-1 ü ü ü ü
PICDEM-2 ü ü
PICDEM-3 ü
KEELOQ®
Evaluation Kit ü
KEELOQ
Transponder Kit ü
PIC16C55X
DS40143C-page 68 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 69
PIC16C55X
10.0 ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings †
Ambient Temperature under bias ............................................................................................................. –40° to +125°C
Storage Temperature................................................................................................................................ –65° to +150°C
Voltage on any pin with respect to VSS (except VDD and MCLR)...................................................... –0.6V to VDD +0.6V
Voltage on VDD with respect to VSS ............................................................................................................... 0 to +7.5V
Voltage on MCLR with respect to VSS (Note 2)................................................................................................. 0 to +14V
Total power Dissipation (Note 1) ...............................................................................................................................1.0W
Maximum Current out of VSS pin...........................................................................................................................300 mA
Maximum Current into VDD pin..............................................................................................................................250 mA
Input Clamp Current, IIK (VI<0 or VI> VDD)...................................................................................................................... ±20 mA
Output Clamp Current, IOK (V0 <0 or V0>VDD)............................................................................................................... ±20 mA
Maximum Output Current sunk by any I/O pin........................................................................................................25 mA
Maximum Output Current sourced by any I/O pin...................................................................................................25 mA
Maximum Current sunk by PORTA and PORTB...................................................................................................200 mA
Maximum Current sourced by PORTA and PORTB..............................................................................................200 mA
Note 1: Power dissipation is calculated as follows: PDIS = VDD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL)
† 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 to maximum rating conditions
for extended periods may affect device reliability.
PIC16C55X
DS40143C-page 70 Preliminary 1998 Microchip Technology Inc.
TABLE 10-1: CROSS REFERENCE OF DEVICE SPECS FOR OSCILLATOR CONFIGURATIONS
AND FREQUENCIES OF OPERATION (COMMERCIAL DEVICES)
OSC PIC16C55X-04 PIC16C55X-20 PIC16LC55X-04 PIC16C55X
JW Devices
RC VDD: 3.0V to
5.5V
IDD: 3.3 mA
max.@5.5V
IPD: 20 µA max.
@4.0V
Freq: 4.0 MHz
max.
VDD: 4.5V to 5.5V
IDD: 1.8 mA typ.
@5.5V
IPD: 1.0 µA typ.
@4.5V
Freq: 4.0 MHz
max.
VDD: 2.5V to 5.5V
IDD: 1.4 mA typ.
@3.0V
IPD: 0.7 µA typ.
@3.0V
Freq: 4.0 MHz
max.
VDD: 3.0V to 5.5V
IDD: 3.3 mA max.
@5.5V
IPD: 20 µA max.
@4.0V
Freq: 4.0 MHz
max.
XT VDD: 3.0V to
5.5V
IDD: 3.3 mA
max.@5.5V
IPD: 20 µA max.
@4.0V
Freq: 4.0 MHz
max.
VDD: 4.5V to 5.5V
IDD: 1.8 mA typ.
@5.5V
IPD: 1.0 µA typ.
@4.5V
Freq: 4.0 MHz
max.
VDD: 2.5V to 5.5V
IDD: 1.4 mA typ.
@3.0V
IPD: 0.7 µA typ.
@3.0V
Freq: 4.0 MHz
max.
VDD: 3.0V to 5.5V
IDD: 3.3 mA max.
@5.5V
IPD: 20 µA max.
@4.0V
Freq: 4.0 MHz
max.
HS VDD: 4.5V to
5.5V
IDD: 9.0 mA typ.
@5.5V
IPD: 1.0 µA typ.
@4.0V
Freq: 4.0 MHz
max.
VDD: 4.5V to
5.5V
IDD: 20 mA
max. @5.5V
IPD: 1.0 µA typ.
@4.5V
Freq: 20 MHz
max.
Do not use in
HS mode
VDD: 4.5V to
5.5V
IDD: 20 mA
max.@5.5V
IPD: 1.0 µA typ.
@4.5V
Freq: 20 MHz
max.
LP VDD: 3.0V to
5.5V
IDD: 35 µA typ.
@32 kHz,
3.0V
IPD: 1.0 µA typ.
@4.0 V
Freq: 200 kHz
maxi.
Do not use in LP mode
VDD: 2.5V to
5.5V
IDD: 32 µA max.
@32 kHz,
3.0V
IPD: 9.0 µA
max. @3.0V
Freq: 200 kHz
max.
VDD: 2.5V to
5.5V
IDD: 32 µA max.
@32 kHz,
3.0V
IPD: 9.0 µA
max. @3.0V
Freq: 200 kHz
max.
The shaded sections indicate oscillator selections which are tested for functionality, but not for MIN/MAX specifications.
It is recommended that the user select the device type that ensures the specifications required.
1998 Microchip Technology Inc. Preliminary DS40143C-page 71
PIC16C55X
(A)
10.1 DC CHARACTERISTICS: PIC16C55X-04 (Commercial, Industrial, Extended)
PIC16C55X-20 (Commercial, Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature –40°C≤ TA ≤ +85°C for industrial and
0°C ≤ TA ≤ +70°C for commercial and
–40°C≤ TA ≤ +125°C for extended
Param
No. Sym Characteristic Min Typ† Max Units Conditions
D001
D001A VDD Supply Voltage 3.0
4.5 -
-5.5
5.5 V
VXT, RC and LP osc configuration
HS osc configuration
D002 VDR RAM Data Retention
Voltage (Note 1) – 1.5* – V Device in SLEEP mode
D003 VPOR VDD start voltage to
ensure Power-on Reset – VSS – V See section on power-on reset for
details
D004 SVDD VDD rise rate to ensure
Power-on Reset 0.05* – – V/ms See section on power-on reset for
details
D010
D010A
D013
IDD Supply Current (Note 2) –
–
–
1.8
35
9.0
3.3
70
20
mA
µA
mA
XT and RC osc configuration
FOSC = 4 MHz, VDD = 5.5V, WDT
disabled (Note 4)
LP osc configuration,
PIC16C55X-04 only
FOSC = 32 kHz, VDD = 4.0V, WDT
disabled
HS osc configuration
FOSC = 20 MHz, VDD = 5.5V, WDT
disabled
D020 IPD Power Down Current (Note 3) – 1.0 2.5
15 µA
µAVDD=4.0V, WDT disabled
(+85°C to +125°C)
∆IWDT WDT Current (Note 5) – 6.0 20 µA VDD=4.0V
(+85°C to +125°C)
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5.0V, 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: The supply current is mainly a function of the operating v oltage 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.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail to rail; all I/O pins configured as input, pulled to VDD,
MCLR = VDD; WDT enabled/disabled as specified.
3: 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 configured as input and tied to VDD or VSS.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be
estimated by the formula Ir = VDD/2Rext (mA) with Rext in kΩ.
5: The ∆ current is the additional current consumed when this peripheral is enabled. This current should be
added to the base IDD or IPD measurement.
PIC16C55X
DS40143C-page 72 Preliminary 1998 Microchip Technology Inc.
10.2 DC CHARACTERISTICS: PIC16LC55X-04 (Commercial, Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature –40˚C ≤ TA ≤ +85˚C for industrial and
0˚C ≤ TA ≤ +70˚C for commercial and
–40˚C ≤ TA ≤ +125˚C for extended
Param
No. Sym Characteristic Min Typ† Max Units Conditions
D001 VDD Supply Voltage 3.0
2.5 - 5.5
5.5 V XT and RC osc configuration
LP osc configuration
D002 VDR RAM Data Retention
Voltage (Note 1) – 1.5* – V Device in SLEEP mode
D003 VPOR VDD start voltage to
ensure Power-on Reset – VSS – V See section on Power-on Reset for
details
D004 SVDD VDD rise rate to ensure
Power-on Reset 0.05* – – V/ms See section on Power-on Reset for
details
D010
D010A
IDD Supply Current (Note 2) –
–
1.4
26
2.5
53
mA
µA
XT and RC osc configuration
FOSC = 2.0 MHz, VDD = 3.0V, WDT
disabled (Note 4)
LP osc configuration
FOSC = 32 kHz, VDD = 3.0V, WDT
disabled
D020 IPD Power Down Current (Note 3) – 0.7 2 µA VDD=3.0V, WDT disabled
∆IWDT WDT Current (Note 5) – 6.0 15 µA VDD=3.0V
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5.0V, 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: The supply current is mainly a function of the operating v oltage 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.
The test conditions for all IDD measurements in active operation mode are:
OSC1=external square wave, from rail to rail; all I/O pins configured as input, pulled to VDD,
MCLR = VDD; WDT enabled/disabled as specified.
3: 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 configured as input and tied to VDD or VSS.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be
estimated by the formula Ir = VDD/2Rext (mA) with Rext in kΩ.
5: The ∆ current is the additional current consumed when this peripheral is enabled. This current should be
added to the base IDD or IPD measurement.
1998 Microchip Technology Inc. Preliminary DS40143C-page 73
PIC16C55X
10.3 DC CHARACTERISTICS: PIC16C55X (Commercial, Industrial, Extended)
PIC16LC55X (Commercial, Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature –40˚C ≤ TA ≤ +85˚C for industrial and
0˚C ≤ TA ≤ +70˚C for commercial and
–40˚C ≤ TA ≤ +125˚C for automotive
Operating voltage VDD range as described in DC spec Table 10-1
Param.
No. Sym Characteristic Min Typ† Max Unit Conditions
VIL Input Low Voltage
I/O ports
D030 with TTL buffer VSS - 0.8V
0.15VDD V VDD = 4.5V to 5.5V
otherwise
D031 with Schmitt Trigger input VSS 0.2VDD V
D032 MCLR, RA4/T0CKI,OSC1 (in
RC mode) Vss - 0.2VDD V Note1
D033 OSC1 (in XT* and HS) Vss - 0.3VDD V
OSC1 (in LP*) Vss - 0.6VDD-1.0 V
VIH Input High Voltage
I/O ports -
D040 with TTL buffer 2.0V - VDD V VDD = 4.5V to 5.5V
D041 with Schmitt Trigger input 0.25VDD
+ 0.8V VDD otherwise
D042 MCLR RA4/T0CKI 0.8VDD - VDD V
D043
D043A OSC1 (XT*, HS and LP*)
OSC1 (in RC mode) 0.7VDD
0.9VDD - VDD VNote1
D070 IPURB PORTB weak pull-up current 50 200 400 µA VDD = 5.0V, VPIN = VSS
IIL Input Leakage Current
(Notes 2, 3)
I/O ports (Except PORTA) ±1.0 µA VSS ≤ VPIN ≤ VDD, pin at hi-impedance
D060 PORTA - - ±0.5 µA Vss ≤ VPIN ≤ VDD, pin at hi-impedance
D061 RA4/T0CKI - - ±1.0 µA Vss ≤ VPIN ≤ VDD
D063 OSC1, MCLR - - ±5.0 µA Vss ≤ VPIN ≤ VDD, XT, HS and LP osc
configuration
VOL Output Low Voltage
D080 I/O ports - - 0.6 V IOL=8.5 mA, VDD=4.5V, -40° to +85°C
- - 0.6 V IOL=7.0 mA, VDD=4.5V, +125°C
D083 OSC2/CLKOUT - - 0.6 V IOL=1.6 mA, VDD=4.5V, -40° to +85°C
(RC only) - - 0.6 V IOL=1.2 mA, VDD=4.5V, +125°C
VOH Output High Voltage (Note 3)
D090 I/O ports (Except RA4) VDD-0.7 - - V IOH=-3.0 mA, VDD=4.5V, -40° to +85°C
VDD-0.7 - - V IOH=-2.5 mA,
VDD=4.5V, +125°C
D092 OSC2/CLKOUT VDD-0.7 - - V IOH=-1.3 mA, VDD=4.5V, -40° to +85°C
(RC only) VDD-0.7 - - V IOH=-1.0 mA,
VDD=4.5V, +125°C
*VOD Open-Drain High Voltage 10* V RA4 pin
* These parameters are characterized but not tested.
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: In RC oscillator configuration, the OSC1 pin is a Schmitt Trigger input. It is not recommended that the
PIC16C55X be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on applied voltage level. The specified levels
represent normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Negative current is defined as coming out of the pin.
PIC16C55X
DS40143C-page 74 Preliminary 1998 Microchip Technology Inc.
Capacitive Loading Specs
on Output Pins
D100 COSC2 OSC2 pin 15 pF In XT, HS and LP modes when external
clock used to drive OSC1.
D101 Cio All I/O pins/OSC2 (in RC
mode) 50 pF
10.3 DC CHARACTERISTICS: PIC16C55X (Commercial, Industrial, Extended)
PIC16LC55X (Commercial, Industrial, Extended) (Cont.)
Standard Operating Conditions (unless otherwise stated)
Operating temperature –40˚C ≤ TA ≤ +85˚C for industrial and
0˚C ≤ TA ≤ +70˚C for commercial and
–40˚C ≤ TA ≤ +125˚C for automotive
Operating voltage VDD range as described in DC spec Table 10-1
Param.
No. Sym Characteristic Min Typ† Max Unit Conditions
* These parameters are characterized but not tested.
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: In RC oscillator configuration, the OSC1 pin is a Schmitt Trigger input. It is not recommended that the
PIC16C55X be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on applied voltage level. The specified levels
represent normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Negative current is defined as coming out of the pin.
1998 Microchip Technology Inc. Preliminary DS40143C-page 75
PIC16C55X
10.4 Timing Parameter Symbology
The timing parameter symbols have been created with one of the following formats:
FIGURE 10-1: LOAD CONDITIONS
1. TppS2ppS
2. TppS
TF Frequency T Time
Lowercase subscripts (pp) and their meanings:
pp
ck CLKOUT os OSC1
io I/O port t0 T0CKI
mc MCLR
Uppercase letters and their meanings:
SF Fall P Period
H High R Rise
I Invalid (Hi-impedance) V Valid
L Low Z Hi-Impedance
VDD/2
CL
RL
Pin Pin
VSS VSS
CL
RL= 464Ω
CL= 50 pF for all pins except OSC2
15 pF for OSC2 output
Load condition 1 Load condition 2
PIC16C55X
DS40143C-page 76 Preliminary 1998 Microchip Technology Inc.
10.5 Timing Diagrams and Specifications
FIGURE 10-2: EXTERNAL CLOCK TIMING
TABLE 10-2: EXTERNAL CLOCK TIMING REQUIREMENTS
Parameter
No. Sym Characteristic Min Typ† Max Units Conditions
Fos External CLKIN Frequency
(Note 1) DC — 4 MHz XT and RC osc mode, VDD=5.0V
DC — 20 MHz HS osc mode
DC — 200 kHz LP osc mode
Oscillator Frequency
(Note 1) DC — 4 MHz RC osc mode, VDD=5.0V
0.1 — 4 MHz XT osc mode
1 — 20 MHz HS osc mode
DC – 200 kHz LP osc mode
1 Tosc External CLKIN Period
(Note 1) 250 — — ns XT and RC osc mode
50 — — ns HS osc mode
5 — — µs LP osc mode
Oscillator Period
(Note 1) 250 — — ns RC osc mode
250 — 10,000 ns XT osc mode
50 — 1,000 ns HS osc mode
5 — — µs LP osc mode
2 TCY Instruction Cycle Time (Note 1) 1.0 Fos/4 DC µsTCY=FOS/4
3* TosL,
TosH External Clock in (OSC1) High or
Low Time 100* — — ns XT osc mode
2* — — µs LP osc mode
20* — — ns HS osc mode
4* TosR,
TosF External Clock in (OSC1) Rise or
Fall Time 25* — — ns XT osc mode
50* — — ns LP osc mode
15* — — ns HS osc mode
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Instruction cycle period (TCY) equals f our 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 e xpected current consumption. All devices are tested to operate at "min." values with an
external clock applied to the OSC1 pin.
When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices.
OSC1
CLKOUT
Q4 Q1 Q2 Q3 Q4 Q1
1 3 3 4 4
2
1998 Microchip Technology Inc. Preliminary DS40143C-page 77
PIC16C55X
FIGURE 10-3: CLKOUT AND I/O TIMING
TABLE 10-3: CLKOUT AND I/O TIMING REQUIREMENTS
Parameter # Sym Characteristic Min Typ† Max Units
10* TosH2ckL OSC1↑ to CLKOUT↓ (Note1) —
—75
—200
400 ns
ns
11* TosH2ckH OSC1↑ to CLKOUT↑ (Note1) —
—75
—200
400 ns
ns
12* TckR CLKOUT rise time (Note1) —
—35
—100
200 ns
ns
13* TckF CLKOUT fall time (Note1) —
—35
—100
200 ns
ns
14* TckL2ioV CLKOUT ↓ to Port out valid (Note1) — — 20 ns
15* TioV2ckH Port in valid before CLKOUT ↑ (Note1) Tosc +200 ns
Tosc +400 ns —
——
—ns
ns
16* TckH2ioI Port in hold after CLKOUT ↑ (Note1) 0 — — ns
17* TosH2ioV OSC1↑ (Q1 cycle) to Port out valid —
—50 150
300 ns
ns
18* TosH2ioI OSC1↑ (Q2 cycle) to P ort input invalid (I/O in hold
time) 100
200 —
——
—ns
ns
19* TioV2osH Port input valid to OSC1↑ (I/O in setup time) 0 — — ns
20* TioR Port output rise time —
—10
—40
80 ns
ns
21* TioF Port output fall time —
—10
—40
80 ns
ns
22* Tinp RB0/INT pin high or low time 25
40 —
——
—ns
ns
23 Trbp RB<7:4> change interrupt high or low time Tcy — — ns
* These parameters are characterized but not tested
†Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These par ameters are for design guidance only and are not tested.
Note 1: Measurements are taken in RC Mode where CLKOUT output is 4 x TOSC
22
23
Note: All tests must be do with specified capacitance loads (Figure 10-1) 50 pF on I/O pins and CLKOUT
OSC1
CLKOUT
I/O Pin
(input)
I/O Pin
(output)
Q4 Q1 Q2 Q3
10
13 14
17
20, 21
19 18
15
11
12 16
old value new value
PIC16C55X
DS40143C-page 78 Preliminary 1998 Microchip Technology Inc.
FIGURE 10-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
TABLE 10-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER REQUIREMENTS
Parameter
No. Sym Characteristic Min Typ† Max Units Conditions
30 TmcL MCLR Pulse Width (low) 2000 — — ns -40° to +85°C
31 Twdt Watchdog Timer Time-out Period
(No Prescaler) 7* 18 33* ms VDD = 5.0V, -40° to +85°C
32 Tost Oscillation Start-up Timer Period — 1024 TOSC — — TOSC = OSC1 period
33 Tpwrt Power-up Timer Period 28* 72 132* ms VDD = 5.0V, -40° to +85°C
34 TIOZ I/O hi-impedance from MCLR low — 2.0 µs
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
VDD
MCLR
Internal
POR
PWRT
Timeout
OSC
Timeout
Internal
RESET
Watchdog
Timer
RESET
33
32
30
31
34
I/O Pins
34
1998 Microchip Technology Inc. Preliminary DS40143C-page 79
PIC16C55X
FIGURE 10-5: TIMER0 CLOCK TIMING
TABLE 10-5: TIMER0 CLOCK REQUIREMENTS
FIGURE 10-6: LOAD CONDITIONS
Parameter
No. Sym Characteristic Min Typ† Max Units Conditions
40 Tt0H T0CKI High Pulse Width No Prescaler 0.5 TCY + 20* — — ns
With Prescaler 10* — — ns
41 Tt0L T0CKI Low Pulse Width No Prescaler 0.5 TCY + 20* — — ns
With Prescaler 10* — — ns
42 Tt0P T0CKI Period TCY + 40*
N— — ns N = prescale value
(1, 2, 4, ..., 256)
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
41
42
40
RA4/T0CKI
TMR0
VDD/2
CL
RL
Pin Pin
VSS VSS
CL
RL= 464Ω
CL= 50 pF for all pins except OSC2
15 pF for OSC2 output
Load condition 1 Load condition 2
PIC16C55X
DS40143C-page 80 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 81
PIC16C55X
11.0 PACKAGING INFORMATION
11.1 Package Marking Information
20-Lead SSOP
XXXXXXXXXXX
AABBCDE
XXXXXXXXXXX
XXXXXXXX
XXXXXXXX
AABBCDE
18-Lead CERDIP Windowed
18-Lead SOIC (.300")
XXXXXXXXXXXX
AABBCDE
XXXXXXXXXXXX
XXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
AABBCDE
18-Lead PDIP
Example
-04I / 218
9851 CBP
PIC16C558
16C558
/JW
9801 CBA
Example
Example
-04I / S0218
9818 CDK
PIC16C558
PIC16C558
-04I / P456
9823 CBA
Example
Legend: MM...M Microchip part number information
XX...X Customer specific information*
AA Year code (last 2 digits of calendar year)
BB Week code (week of January 1 is week ‘01’)
C Facility code of the plant at which wafer is manufactured
O = Outside Vendor
C = 5” Line
S = 6” Line
H = 8” Line
D Mask revision number
E Assembly code of the plant or country of origin in which
part was assembled
Note:In the e v ent the full Microchip part number cannot be mark ed on one line, it will
be carried over to the next line thus limiting the number of available characters
for customer specific information.
PIC16C55X
DS40143C-page 82 Preliminary 1998 Microchip Technology Inc.
Package Type: K04-010 18-Lead Ceramic Dual In-line with Window (JW) – 300 mil
* Controlling Parameter.
JEDEC equivalent: MO-036 AE
n
2
1
R
MIN
Window Length
Window Width
Overall Row Spacing
Radius to Radius Width
Package Width
Package Length
Tip to Seating Plane
Base to Seating Plane
Top of Lead to Seating Plane
Top to Seating Plane
Lead Thickness
Shoulder Radius
Upper Lead Width
Lower Lead Width
Number of Pins
PCB Row Spacing
Dimension Limits
Pitch
Units
eB
W2
W1
L
E
E1
D
A1
A2
A
B
c
R
B1
n
p
0.15
7.24
7.87
0.76
3.33
4.83
0.30
0.38
1.52
0.53
2.59
0.200
0.140
0.385
0.270
0.298
0.900
0.138
0.023
0.111
0.183
0.190
0.130
0.345
0.125
0.255
0.285
0.880
0.015
0.091
0.175
0.210
0.150
0.425
0.150
0.285
0.310
0.920
0.030
0.131
0.190
0.010
0.013
0.055
0.019
0.100
0.300
NOM
0.016
0.008
0.010
0.050
0.098
INCHES* MAX
18
0.021
0.012
0.015
0.060
0.102
22.86
0.19
0.13
8.76
6.48
7.24
22.35
3.18
0.00
2.31
4.45
0.2
0.14
9.78 10.80
0.21
3.49
6.86
7.56
0.57
2.82
4.64
3.81
23.37
NOM
MILLIMETERS
MIN
0.20
0.25
1.27
0.41
2.49
MAX
0.47
0.25
0.32
1.40
2.54
18
7.62
D
W2
E
W1
c
eB
E1
p
L
A1
B
B1
A
A2
1998 Microchip Technology Inc. Preliminary DS40143C-page 83
PIC16C55X
Package Type: K04-007 18-Lead Plastic Dual In-line (P) – 300 mil
* Controlling Parameter.
†Dimension “B1” does not include dam-bar protrusions. Dam-bar protrusions shall not exceed 0.003”
(0.076 mm) per side or 0.006” (0.152 mm) more than dimension “B1.”
‡Dimensions “D” and “E” do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed 0.010” (0.254 mm) per side or 0.020” (0.508 mm) more than dimensions “D” or “E.”
JEDEC equivalent: MS-001 AC
Units INCHES* MILLIMETERS
Dimension Limits MIN NOM MAX MIN NOM MAX
PCB Row Spacing 0.300 7.62
Number of Pins n 18 18
Pitch p 0.100 2.54
Lower Lead Width B 0.013 0.018 0.023 0.33 0.46 0.58
Upper Lead Width B1†0.055 0.060 0.065 1.40 1.52 1.65
Shoulder Radius R 0.000 0.005 0.010 0.00 0.13 0.25
Lead Thickness c 0.005 0.010 0.015 0.13 0.25 0.38
Top to Seating Plane A 0.110 0.155 0.155 2.79 3.94 3.94
Top of Lead to Seating Plane A1 0.075 0.095 0.115 1.91 2.41 2.92
Base to Seating Plane A2 0.000 0.020 0.020 0.00 0.51 0.51
Tip to Seating Plane L 0.125 0.130 0.135 3.18 3.30 3.43
Package Length D‡0.890 0.895 0.900 22.61 22.73 22.86
Molded Package Width E‡0.245 0.255 0.265 6.22 6.48 6.73
Radius to Radius Width E1 0.230 0.250 0.270 5.84 6.35 6.86
Overall Row Spacing eB 0.310 0.349 0.387 7.87 8.85 9.83
Mold Draft Angle Top α5 10 15 5 10 15
Mold Draft Angle Bottom β5 10 15 5 10 15
R
n
2
1
D
E
c
eB
β
E1
α
p
A1
L
B1
B
A
A2
PIC16C55X
DS40143C-page 84 Preliminary 1998 Microchip Technology Inc.
Package Type: K04-051 18-Lead Plastic Small Outline (SO) – Wide, 300 mil
0.014
0.009
0.010
0.011
0.005
0.005
0.010
0.394
0.292
0.450
0.004
0.048
0.093
MIN
nNumber of Pins
Mold Draft Angle Bottom
Mold Draft Angle Top
Lower Lead Width
Chamfer Distance
Outside Dimension
Molded Package Width
Molded Package Length
Overall Pack. Height
Lead Thickness
Radius Centerline
Foot Angle
Foot Length
Gull Wing Radius
Shoulder Radius
Standoff
Shoulder Height
β
α
R2
R1
E1
A2
A1
X
φ
B†
c
L1
L
E‡
D‡
A
Dimension Limits
Pitch
Units
p1818
0
012
12 15
15
4
0.020
0
0.017
0.011
0.015
0.016
0.005
0.005
0.407
0.296
0.456
0.008
0.058
0.099
0.029
0.019
0.012
0.020
0.021
0.010
0.010
8
0.419
0.299
0.462
0.011
0.068
0.104
0
012
12 15
15
0.42
0.27
0.38
0.41
0.13
0.13
0.50
10.33
7.51
11.58
0.19
1.47
2.50
0.25
0
0.36
0.23
0.25
0.28
0.13
0.13
10.01
7.42
11.43
0.10
1.22
2.36
0.74
4 8
0.48
0.30
0.51
0.53
0.25
0.25
10.64
7.59
11.73
0.28
1.73
2.64
INCHES*
0.050
NOM MAX 1.27
MILLIMETERS
MIN NOM MAX
n2
1
R2
R1
L1
L
β
c
φ
X
45°
D
p
B
E
E1
α
A1
A2
A
* Controlling Parameter.
†Dimension “B” does not include dam-bar protrusions. Dam-bar protrusions shall not exceed 0.003”
(0.076 mm) per side or 0.006” (0.152 mm) more than dimension “B.”
‡Dimensions “D” and “E” do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed 0.010” (0.254 mm) per side or 0.020” (0.508 mm) more than dimensions “D” or “E.”
JEDEC equivalent: MS-013 AB
1998 Microchip Technology Inc. Preliminary DS40143C-page 85
PIC16C55X
Package Type: K04-072 20-Lead Plastic Shrink Small Outine (SS) – 5.30 mm
MIN
pPitch
Mold Draft Angle Bottom
Mold Draft Angle Top
Lower Lead Width
Radius Centerline
Gull Wing Radius
Shoulder Radius
Outside Dimension
Molded Package Width
Molded Package Length
Shoulder Height
Overall Pack. Height
Lead Thickness
Foot Angle
Foot Length
Standoff
Number of Pins
β
α
c
φ
A2
A1
A
n
E1
B†
L1
R2
L
R1
E‡
D‡
Dimension Limits
Units
0.650.026
8
0
05
5 10
10
0.012
0.007
0.005
0.020
0.005
0.005
0.306
0.208
0.283
0.005
0.036
0.073
20
0.301
0
0.010
0.005
0.000
0.015
0.005
0.005
0.205
0.278
0.002
0.026
0.068
0.311
0.015
0.009
0.010
0.025
0.010
0.010
4 8
0.212
0.289
0.008
0.046
0.078
0
0 5
5 10
10
7.65
0.25
0.13
0.00
0.38
0.13
0.13
0
5.20
7.07
0.05
0.66
1.73
7.907.78
4
0.32
0.18
0.13
0.13
0.51
0.13
0.38
0.22
0.25
0.25
0.64
0.25
5.29
7.20
0.13
20
1.86
0.91
5.38
7.33
0.21
1.99
1.17
NOM
INCHES MAX NOM
MILLIMETERS*
MIN MAX
n1
2
R1
R2
D
p
B
E1
E
L1
L
c
β
φ
α
A1
A
A2
* Controlling Parameter.
†Dimension “B” does not include dam-bar protrusions. Dam-bar protrusions shall not exceed 0.003”
(0.076 mm) per side or 0.006” (0.152 mm) more than dimension “B.”
‡Dimensions “D” and “E” do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed 0.010” (0.254 mm) per side or 0.020” (0.508 mm) more than dimensions “D” or “E.”
JEDEC equivalent: MO-150 AE
PIC16C55X
DS40143C-page 86 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 87
PIC16C55X
APPENDIX A: ENHANCEMENTS
The following are the list of enhancements over the
PIC16C5X microcontroller family:
1. Instruction word length is increased to 14 bits.
This allows larger page sizes both in program
memory (4K now as opposed to 512 bef ore) and
register file (up to 128 bytes now versus 32
bytes before).
2. A PC high latch register (PCLATH) is added to
handle program memory paging. PA2, PA1, PA0
bits are removed from STATUS register.
3. Data memory paging is slightly redefined.
STATUS register is modified.
4. Four new instructions have been added:
RETURN, RETFIE, ADDLW, and SUBLW.
Two instructions TRIS and OPTION are being
phased out although they are kept for
compatibility with PIC16C5X.
5. OPTION and TRIS registers are made
addressable.
6. Interrupt capability is added. Interrupt vector is
at 0004h.
7. Stack size is increased to 8 deep.
8. Reset vector is changed to 0000h.
9. Reset of all registers is revised. Three different
reset (and wake-up) types are recognized.
Registers are reset differently.
10. Wake up from SLEEP through interrupt is
added.
11. Two separate timers, Oscillator Start-up Timer
(OST) and Power-up Timer (PWRT) are
included for more reliable power-up. These
timers are invoked selectively to avoid
unnecessary delays on power-up and wake-up.
12. PORTB has weak pull-ups and interrupt on
change feature.
13. Timer0 clock input, T0CKI pin is also a por t pin
(RA4/T0CKI) and has a TRIS bit.
14. FSR is made a full 8-bit register.
15. “In-circuit programming” is made possible. The
user can program PIC16C55X devices using
only five pins: VDD, VSS, VPP, RB6 (clock) and
RB7 (data in/out).
16. PCON status register is added with a
Power-on-Reset (POR) status bit.
17. Code protection scheme is enhanced such that
portions of the program memory can be
protected, while the remainder is unprotected.
18. PORTA inputs are now Schmitt Trigger inputs.
APPENDIX B: COMPATIBILITY
To conver t code wr itten for PIC16C5X to PIC16C55X,
the user should take the following steps:
1. Remove any program memory page select
operations (PA2, PA1, PA0 bits) for CALL, GOTO.
2. Revisit any computed jump operations (write to
PC or add to PC, etc.) to make sure page bits
are set properly under the new scheme.
3. Eliminate any data memory page switching.
Redefine data variables to reallocate them.
4. Verify all writes to STATUS, OPTION, and FSR
registers since these have changed.
5. Change reset vector to 0000h.
PIC16C55X
DS40143C-page 88 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 89
PIC16C55X
INDEX
A
ADDLW Instruction .............................................................53
ADDWF Instruction.............................................................53
ANDLW Instruction .............................................................53
ANDWF Instruction.............................................................53
Architectural Overview..........................................................9
Assembler
MPASM Assembler.....................................................65
B
BCF Instruction...................................................................54
Block Diagram
TIMER0.......................................................................29
TMR0/WDT PRESCALER..........................................32
BSF Instruction ...................................................................54
BTFSC Instruction...............................................................54
BTFSS Instruction...............................................................55
C
CALL Instruction .................................................................55
Clocking Scheme/Instruction Cycle ....................................12
CLRF Instruction.................................................................55
CLRW Instruction................................................................55
CLRWDT Instruction...........................................................56
Code Protection..................................................................50
COMF Instruction................................................................56
Configuration Bits................................................................36
D
Data Memory Organization.................................................13
DECF Instruction.................................................................56
DECFSZ Instruction............................................................56
Development Support.........................................................63
Development Tools.............................................................63
E
Errata....................................................................................3
External Crystal Oscillator Circuit .......................................38
F
Fuzzy Logic Dev. System (
fuzzy
TECH-MP) ....................65
G
General purpose Register File............................................13
GOTO Instruction................................................................57
I
I/O Ports..............................................................................23
I/O Programming Considerations........................................27
ICEPIC Low-Cost PIC16CXXX In-Circuit Emulator............63
ID Locations........................................................................50
INCF Instruction..................................................................57
INCFSZ Instruction .............................................................57
In-Circuit Serial Programming.............................................50
Indirect Addressing, INDF and FSR Registers ...................21
Instruction Flow/Pipelining..................................................12
Instruction Set
ADDLW.......................................................................53
ADDWF.......................................................................53
ANDLW.......................................................................53
ANDWF.......................................................................53
BCF.............................................................................54
BSF.............................................................................54
BTFSC........................................................................54
BTFSS ........................................................................55
CALL...........................................................................55
CLRF...........................................................................55
CLRW .........................................................................55
CLRWDT.................................................................... 56
COMF......................................................................... 56
DECF.......................................................................... 56
DECFSZ..................................................................... 56
GOTO......................................................................... 57
INCF........................................................................... 57
INCFSZ....................................................................... 57
IORLW........................................................................ 57
IORWF........................................................................ 58
MOVF......................................................................... 58
MOVLW...................................................................... 58
MOVWF...................................................................... 58
NOP............................................................................ 59
OPTION...................................................................... 59
RETFIE....................................................................... 59
RETLW....................................................................... 59
RETURN..................................................................... 60
RLF............................................................................. 60
RRF............................................................................ 60
SLEEP........................................................................ 60
SUBLW....................................................................... 61
SUBWF....................................................................... 61
SWAPF....................................................................... 62
TRIS ........................................................................... 62
XORLW ...................................................................... 62
XORWF...................................................................... 62
Instruction Set Summary .................................................... 51
INT Interrupt ....................................................................... 46
INTCON Register ............................................................... 18
Interrupts ............................................................................ 45
IORLW Instruction .............................................................. 57
IORWF Instruction.............................................................. 58
K
KeeLoq Evaluation and Programming Tools................... 66
M
MOVF Instruction................................................................ 58
MOVLW Instruction ............................................................ 58
MOVWF Instruction ............................................................ 58
MPLAB Integrated Development Environment Software.... 65
N
NOP Instruction .................................................................. 59
O
One-Time-Programmable (OTP) Devices .............................7
OPTION Instruction ............................................................ 59
OPTION Register ............................................................... 17
Oscillator Configurations .................................................... 37
Oscillator Start-up Timer (OST).......................................... 40
P
Package Marking Information............................................. 81
Packaging Information........................................................ 81
PCL and PCLATH .............................................................. 20
PCON Register................................................................... 19
PICDEM-1 Low-Cost PICmicro Demo Board ..................... 64
PICDEM-2 Low-Cost PIC16CXX Demo Board................... 64
PICDEM-3 Low-Cost PIC16CXXX Demo Board ................ 64
PICSTART Plus Entry Level Development System......... 63
Pinout Description .............................................................. 11
Port RB Interrupt................................................................. 46
PORTA ............................................................................... 23
PORTB ............................................................................... 25
Power Control/Status Register (PCON) ............................. 41
Power-Down Mode (SLEEP).............................................. 49
Power-On Reset (POR)...................................................... 40
Power-up Timer (PWRT).................................................... 40
PIC16C55X
DS40143C-page 90 Preliminary 1998 Microchip Technology Inc.
Prescaler.............................................................................32
PRO MATE II Universal Programmer...............................63
Program Memory Organization...........................................13
Q
Quick-Turnaround-Production (QTP) Devices......................7
R
RC Oscillator.......................................................................38
Reset...................................................................................39
RETFIE Instruction..............................................................59
RETLW Instruction..............................................................59
RETURN Instruction............................................................60
RLF Instruction....................................................................60
RRF Instruction...................................................................60
S
SEEVAL Evaluation and Programming System...............65
Serialized Quick-Turnaround-Production (SQTP) Devices...7
SLEEP Instruction...............................................................60
Software Simulator (MPLAB-SIM).......................................65
Special Features of the CPU...............................................35
Special Function Registers .................................................15
Stack...................................................................................20
Status Register....................................................................16
SUBLW Instruction..............................................................61
SUBWF Instruction..............................................................61
SWAPF Instruction..............................................................62
T
Timer0
TIMER0.......................................................................29
TIMER0 (TMR0) Interrupt...........................................29
TIMER0 (TMR0) Module.............................................29
TMR0 with External Clock...........................................31
Timer1
Switching Prescaler Assignment.................................33
Timing Diagrams and Specifications...................................76
TMR0 Interrupt....................................................................46
TRIS Instruction ..................................................................62
TRISA..................................................................................23
TRISB..................................................................................25
W
Watchdog Timer (WDT)......................................................47
WWW, On-Line Support........................................................3
X
XORLW Instruction .............................................................62
XORWF Instruction.............................................................62
1998 Microchip Technology Inc. DS40143C-page 91
PIC16C55X
Systems Information and Upgrade Hot Line
The Systems Information and Upgrade Line provides
system users a listing of the latest versions of all of
Microchip's development systems software products.
Plus, this line provides information on how customers
can receive any currently available upgrade kits.The
Hot Line Numbers are:
1-800-755-2345 for U.S. and most of Canada, and
1-602-786-7302 for the rest of the world.
Trademarks: The Microchip name, logo, PIC, PICmicro,
PICSTART, PICMASTER and PRO MATE are registered
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
Flex
ROM, MPLAB and
fuzzy-
LAB are trademarks and SQTP is a service mark of Micro-
chip in the U.S.A.
All other trademarks mentioned herein are the property of
their respective companies.
ON-LINE SUPPORT
Microchip provides on-line support on the Microchip
World Wide Web (WWW) site.
The web site is used b y Microchip as a means to mak e
files and information easily available to customers. To
view the site , the user must ha ve access to the Internet
and a web browser, such as Netscape or Microsoft
Explorer. Files are also available for FTP download
from our FTP site.
Connecting to the Microchip Internet Web Site
The Microchip web site is available by using your
favorite Internet browser to attach to:
www.microchip.com
The file transfer site is available by using an FTP ser-
vice to connect to:
ftp://ftp.microchip.com
The web site and file transf er site pro vide a v ariety of
services. Users may download files for the latest
Development Tools, Data Sheets, Application Notes,
User's Guides, Articles and Sample Programs. A vari-
ety of Microchip specific business information is also
available, including listings of Microchip sales offices,
distributors and factory representatives. Other data
available for consideration is:
• Latest Microchip Press Releases
• Technical Support Section with Frequently Asked
Questions
• Design Tips
• Device Errata
• Job Postings
• Microchip Consultant Program Member Listing
• Links to other useful web sites related to
Microchip Products
• Conferences for products , De velopment Systems ,
technical information and more
• Listing of seminars and events
981103
PIC16C55X
DS40143C-page 92 1998 Microchip Technology Inc.
READER RESPONSE
It is our intention to provide y ou with the best documentation possible to ensure successful use of your Microchip prod-
uct. If you wish to provide y our comments on organization, clarity, subject matter , and wa ys in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (602) 786-7578.
Please list the following information, and use this outline to provide us with your comments about this Data Sheet.
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this data sheet easy to follow? If not, why?
4. What additions to the data sheet do you think would enhance the structure and subject?
5. What deletions from the data sheet could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
8. How would you improve our software, systems, and silicon products?
To: Technical Publications Manager
RE: Reader Response Total Pages Sent
From: Name
Company
Address
City / State / ZIP / Country
Telephone: (_______) _________ - _________
Application (optional):
Would you like a reply? Y N
Device: Literature Number:
Questions:
FAX: (______) _________ - _________
DS40143C
PIC16C55X
1998 Microchip Technology Inc. Preliminary DS40143C-page 93
PIC16C55X
PIC16C55X Product Identification System
To order or to obtain information, e.g., on pricing or delivery, please use the listed part numbers, and refer to the factor y or the listed
sales offices.
* JW Devices are UV erasable and can be programmed to any device configuration. JW Devices meet the electrical requirement of
each oscillator type (including LC devices).
Pattern: 3-Digit Pattern Code for QTP (blank otherwise)
Package: P = PDIP
SO = SOIC (Gull Wing, 300 mil body)
SS = SSOP (209 mil)
JW* = Windowed CERDIP
Temperature - = 0˚C to +70˚C
Range: I = –40˚C to +85˚C
E = –40˚C to +125˚C
Frequency 04 = 200kHz (LP osc)
Range: 04 = 4 MHz (XT and RC osc)
20 = 20 MHz (HS osc)
Device: PIC16C55X :VDD range 3.0V to 5.5V
PIC16C55XT:VDD range 3.0V to 5.5V (Tape and Reel)
PIC16LC55X:VDD range 2.5V to 5.5V
PIC16LC55XT:VDD range 2.5V to 5.5V (Tape and Reel)
Examples:
f) PIC16C554 - 04/P 301 =
Commercial temp., PDIP pack-
age, 4 MHz, normal VDD limits,
QTP pattern #301.
g) PIC16LC558- 04I/SO =
Industrial temp., SOIC pack-
age, 200kHz, extended VDD
limits.
PART
NO
. -
XX
X
/XX
XXX
Sales and Support
Products supported by a preliminary Data Sheet may possibly have an errata sheet describing minor operational differences and
recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
Your local Microchip sales office (see below)
The Microchip Corporate Literature Center U.S. FAX: (602) 786-7277
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
For latest version information and upgrade kits for Microchip Development Tools, please call 1-800-755-2345 or 1-602-786-7302.
1.
2.
.
PIC16C55X
DS40143C-page 94 Preliminary 1998 Microchip Technology Inc.
NOTES:
1998 Microchip Technology Inc. Preliminary DS40143C-page 95
PIC16C55X
NOTES:
2002 Microchip Technology Inc.
Information contained in this publication regarding device
applications and the like is intended through sug gestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microc hip Technology Incorporated with respect
to the accuracy or use of such inf orm ation, or inf ringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical com-
ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con-
veyed, implicitly or otherwise, under any intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, FilterLab,
KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER,
PICSTART, PRO MATE, SEEVAL and The Embedded Control
Solutions Company are registered trademarks of Microchip T ech-
nology Incorporated in the U.S.A. and other countries.
dsPIC, ECONOMONITOR, FanSense, FlexRO M, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, microPort,
Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM,
MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode
and Total Endurance are trademarks of Microchip Technology
Incorporated in the U.S.A.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorpora ted in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2002, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and T empe, Arizona in July 1999. The
Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro® 8-bit MCUs, KEELOQ® code ho pp in g
devices, Serial EEPROMs and microperipheral
products. In addition, Microchip’s quality
system for the design and manufacture of
development systems is ISO 9001 certified.
Note the following details of the code protection feature on PICmicro® MCUs.
•The PICmicro family meets the specifications contained in the Microchip Data Sheet.
•Microchip believes that its family of PICmicro microcontrollers is one of the most secure product s 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 knowl-
edge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet.
The person doing so may be 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 product.
If you have any further questions about this matter, please contact the local sales office nearest to you.
2002 Microchip Technology Inc.
M
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WORLDWIDE SALES AND SERVICE
