Microchip Technology Inc PIC16C71-04-P, PIC16C71-04I-P, PIC16C71-04I-SO, PIC16C710-20-SO, PIC16C710-20I-P Datasheet



1997 Microchip Technology Inc. DS30272A-page 1

PIC16C71X

8-Bit CMOS Microcontrollers with A/D Converter

Devices included in this data sheet:

• PIC16C710

• PIC16C71

• PIC16C711

• PIC16C715

PIC16C71X Microcontroller Core Features:

• High-performance RISC CPU

• Only 35 single word instructions to learn

• All single cycle instructions except for program
branches which are two cycle

• Operating speed: DC - 20 MHz clock input

DC - 200 ns instruction cycle

• Up to 2K x 14 words of Program Memory,
up to 128 x 8 bytes of Data Memory (RAM)

• Interrupt capability

• Eight level deep hardware stack

• Direct, indirect, and relative addressing modes

• 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

• Programmable code-protection

• Power saving SLEEP mode

• Selectable oscillator options

• Low-power, high-speed CMOS EPROM
technology

• Fully static design

• Wide operating voltage range: 2.5V to 6.0V

• High Sink/Source Current 25/25 mA

• Commercial, Industrial and Extended temperature
ranges

• Program Memory Parity Error Checking Circuitry
with Parity Error Reset (PER) (PIC16C715)

• Low-power consumption:

- < 2 mA @ 5V, 4 MHz

- 15 µ A typical @ 3V, 32 kHz

- < 1 µ A typical standby current

PIC16C71X Peripheral Features:

• Timer0: 8-bit timer/counter with 8-bit prescaler

• 8-bit multichannel analog-to-digital converter

• Brown-out detection circuitry for
Brown-out Reset (BOR)

• 13 I/O Pins with Individual Direction Control

Pin Diagrams

PIC16C7X Features 710 71 711 715

Program Memory (EPROM)
x 14

512 1K 1K 2K

Data Memory (Bytes) x 8 36 36 68 128
I/O Pins 13 13 13 13
Timer Modules 1 1 1 1
A/D Channels 4 4 4 4
In-Circuit Serial Programming Yes Yes Yes Yes
Brown-out Reset Yes — Yes Yes
Interrupt Sources 4 4 4 4

RA2/AN2

RA3/AN3/V

REF

RA4/T0CKI

MCLR/VPP

VSS
VSS

RB0/INT

RB1
RB2
RB3

RA1/AN1
RA0/AN0
OSC1/CLKIN
OSC2/CLKOUT

V

DD

RB7
RB6
RB5
RB4

• 1
2
3
4
5
6
7
8
9
10

20
19
18
17
16
15
14
13
12
11

VDD

SSOP

RA2/AN2

RA3/AN3/V

REF

RA4/T0CKI

MCLR/VPP

VSS

RB0/INT

RB1
RB2
RB3

RA1/AN1
RA0/AN0
OSC1/CLKIN
OSC2/CLKOUT
V

DD

RB7
RB6
RB5
RB4

• 1
2
3
4
5
6
7
8
9

18
17
16
15
14
13
12
11
10

PIC16C710

PDIP, SOIC, Windowed CERDIP

PIC16C71

PIC16C711

PIC16C715

PIC16C710

PIC16C711

PIC16C715

PIC16C71X

DS30272A-page 2

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1997 Microchip Technology Inc.

Table of Contents

1.0 General Description.................................................................................................................................................................... 3

2.0 PIC16C71X Device Varieties......................................................................................................................................................5

3.0 Architectural Overview................................................................................................................................................................7

4.0 Memory Organization ............................................................................................................................................................... 11

5.0 I/O Ports.................................................................................................................................................................................... 25

6.0 Timer0 Module..........................................................................................................................................................................31

7.0 Analog-to-Digital Converter (A/D) Module ................................................................................................................................ 37

8.0 Special Features of the CPU .................................................................................................................................................... 47

9.0 Instruction Set Summary .......................................................................................................................................................... 69

10.0 Development Support............................................................................................................................................................... 85

11.0 Electrical Characteristics for PIC16C710 and PIC16C711....................................................................................................... 89

12.0 DC and AC Characteristics Graphs and Tables for PIC16C710 and PIC16C711..................................................................101

13.0 Electrical Characteristics for PIC16C715................................................................................................................................ 111

14.0 DC and AC Characteristics Graphs and Tables for PIC16C715 ............................................................................................ 125

15.0 Electrical Characteristics for PIC16C71.................................................................................................................................. 135

16.0 DC and AC Characteristics Graphs and Tables for PIC16C71 .............................................................................................. 147

17.0 Packaging Information............................................................................................................................................................ 155

Appendix A: ...................................................................................................................................................................................... 161

Appendix B: Compatibility................................................................................................................................................................. 161

Appendix C: What’s New.................................................................................................................................................................. 162

Appendix D: What’s Changed .......................................................................................................................................................... 162

Index .................................................................................................................................................................................................. 163

PIC16C71X Product Identification System......................................................................................................................................... 173

To Our Valued Customers

We constantly strive to improve the quality of all our products and documentation. We have spent an exceptional
amount of time to ensure that these documents are correct. However, we realize that we may have missed a few
things. If you find any information that is missing or appears in error, please use the reader response form in the
back of this data sheet to inform us. We appreciate your assistance in making this a better document.



1997 Microchip Technology Inc. DS30272A-page 3

PIC16C71X

1.0 GENERAL DESCRIPTION

The PIC16C71X is a family of

low-cost, high-perfor­mance, CMOS, fully-static, 8-bit microcontrollers with
integrated analog-to-digital (A/D) converters, in the
PIC16CXX mid-range family.

All PIC16/17 microcontrollers employ an advanced
RISC architecture. The PIC16CXX microcontroller fam­ily has enhanced core features, eight-level deep stack,
and multiple internal 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 available . Additionally , a large register set giv es
some of the architectural innovations used to achie ve a
very high performance.

PIC16CXX microcontrollers typically achieve a 2:1
code compression and a 4:1 speed improvement over
other 8-bit microcontrollers in their class.

The PIC16C710/71 devices have 36 b ytes of RAM, the

PIC16C711 has 68 bytes of RAM and the PIC16C715

has 128 bytes of RAM. Each device has 13 I/O

pins. In
addition a timer/counter is available. Also a 4-channel
high-speed 8-bit A/D is provided. The 8-bit resolution is
ideally suited for applications requiring low-cost analog
interface, e.g. thermostat control, pressure sensing,
etc.

The PIC16C71X family has special features to reduce
external components, thus reducing cost, enhancing
system reliability and reducing power consumption.
There are four 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 for High Speed crystals. The
SLEEP (power-down) feature provides a power saving
mode. The user can wake up the chip from SLEEP
through several external and internal interrupts and
resets.

A highly reliable Watchdog Timer with its own on-chip
RC oscillator provides protection against software lock­up.

A UV erasable CERDIP packaged version is ideal for
code development while the cost-effective One-Time­Programmable (OTP) version is suitable for production
in any volume.

The PIC16C71X family fits perfectly in applications
ranging from security and remote sensors to appliance
control and automotive. The EPROM technology
makes customization of application programs (trans­mitter codes, motor speeds, receiver frequencies, etc.)
extremely fast and convenient. The small footprint
packages make this microcontroller series perfect for
all applications with space limitations. Low cost, low
power, high perf ormance, ease of use and I/O fle xibility
make the PIC16C71X very versatile even in areas
where no microcontroller use has been considered
before (e.g. timer functions , serial communication, cap­ture and compare, PWM functions and coprocessor
applications).

1.1 F

amily and Upward Compatibility

Users familiar with the PIC16C5X microcontroller fam­ily 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 the
PIC16C5X can be easily ported to the PIC16CXX fam­ily of devices (Appendix B).

1.2 De

velopment Support

PIC16C71X devices are supported by the complete
line of Microchip Development tools.

Please refer to Section 10.0 for more details about
Microchip’s development tools.

PIC16C71X

DS30272A-page 4

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1997 Microchip Technology Inc.

TABLE 1-1: PIC16C71X FAMILY OF DEVICES

PIC16C710

PIC16C71 PIC16C711 PIC16C715 PIC16C72 PIC16CR72

(1)

Clock

Maximum Frequency
of Operation (MHz)

20 20 20 20 20 20

Memory

EPROM Program Memory
(x14 words)

512 1K 1K 2K 2K —

ROM Program Memory
(14K words)

— — — — — 2K

Data Memory (bytes) 36 36 68 128 128 128

Peripherals

Timer Module(s) TMR0 TMR0 TMR0 TMR0 TMR0,

TMR1,
TMR2

TMR0,
TMR1,
TMR2

Capture/Compare/PWM
Module(s)

— — — — 1 1

Serial Port(s)
(SPI/I

2

C, USART)

— — — — SPI/I

2

C SPI/I

2

C

Parallel Slave Port — — — — — —
A/D Converter (8-bit) Channels 4 4 4 4 5 5

Features

Interrupt Sources 4 4 4 4 8 8
I/O Pins 13 13 13 13 22 22
Voltage Range (Volts) 2.5-6.0 3.0-6.0 2.5-6.0 2.5-5.5 2.5-6.0 3.0-5.5
In-Circuit Serial Programming Yes Yes Yes Yes Yes Yes
Brown-out Reset Yes — Yes Yes Yes Yes
Packages 18-pin DIP,

SOIC;
20-pin SSOP

18-pin DIP,
SOIC

18-pin DIP,
SOIC;
20-pin SSOP

18-pin DIP,
SOIC;
20-pin SSOP

28-pin SDIP,
SOIC, SSOP

28-pin SDIP,
SOIC, SSOP

PIC16C73A

PIC16C74A PIC16C76 PIC16C77

Clock

Maximum Frequency
of Operation (MHz)

20 20 20 20

Memory

EPROM Program Memory
(x14 words)

4K 4K 8K 8K

Data Memory (bytes) 192 192 376 376

Peripherals

Timer Module(s) TMR0,

TMR1,
TMR2

TMR0,
TMR1,
TMR2

TMR0,
TMR1,
TMR2

TMR0,
TMR1,
TMR2

Capture/Compare/PWM
Module(s)

2 2 2 2

Serial Port(s)
(SPI/I

2

C, USART)

SPI/I

2

C, USART SPI/I

2

C, USART SPI/I

2

C, USART SPI/I

2

C, USART

Parallel Slave Port — Yes — Yes
A/D Converter (8-bit) Channels 5 8 5 8

Features

Interrupt Sources 11 12 11 12
I/O Pins 22 33 22 33
Voltage Range (Volts) 2.5-6.0 2.5-6.0 2.5-6.0 2.5-6.0
In-Circuit Serial Programming Yes Yes Yes Yes
Brown-out Reset Yes Yes Yes Yes
Packages 28-pin SDIP,

SOIC

40-pin DIP;
44-pin PLCC,
MQFP, TQFP

28-pin SDIP,
SOIC

40-pin DIP;
44-pin PLCC,
MQFP, TQFP

All PIC16/17 Family devices ha v e Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O current capabil­ity . All PIC16C7XX Family devices use serial programming with clock pin RB6 and data pin RB7.
Note 1: Please contact your local Microchip sales office for availability of these devices.



1997 Microchip Technology Inc. DS30272A-page 5

PIC16C71X

2.0 PIC16C71X DEVICE VARIETIES

A variety of frequency ranges and packaging options
are available . Depending on application and production
requirements, the proper device option can be selected
using the information in the PIC16C71X Product Iden­tification System section at the end of this data sheet.
When placing orders, please use that page of the data
sheet to specify the correct part number.

For the PIC16C71X family, there are two device “types”
as indicated in the device number:

1. C , as in PIC16 C 71. These devices have

EPROM type memory and operate over the
standard voltage range.

2. LC , as in PIC16 LC 71. These devices have

EPROM type memory and operate over an
extended voltage range.

2.1 UV Erasab

le 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



Plus and PRO MATE



II
programmers both support programming of the
PIC16C71X.

2.2 One-Time-Pr

ogrammable (OTP)

Devices

The availability of OTP devices is especially useful for
customers who need the flexibility for frequent code
updates and small volume applications.

The OTP devices, packaged in plastic packages, per­mit the user to program them once. In addition to the
program memory, the configuration bits must also be
programmed.

2.3 Quic

k-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 patterns have stabi­lized. The devices are identical to the OTP devices but
with all EPROM locations and configuration options
already programmed by the factory. Certain code and
prototype verification procedures apply before produc­tion shipments are available. Please contact your local
Microchip Technology sales office for more details.

2.4 Serializ

ed 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.

PIC16C71X

DS30272A-page 6



1997 Microchip Technology Inc.

NOTES:



1997 Microchip Technology Inc. DS30272A-page 7

PIC16C71X

3.0 ARCHITECTURAL OVERVIEW

The high performance of the PIC16CXX family can be
attributed to a number of architectural features com­monly found in RISC microprocessors. To begin with,
the PIC16CXX uses a Harvard architecture, in which,
program and data are accessed from separate memo­ries using separate buses. This improves bandwidth
over traditional von Neumann architecture in which pro­gram and data are fetched from the same memory
using the same bus. Separating program and data
buses further allows instructions to be sized differently
than the 8-bit wide data word. 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 two­stage pipeline overlaps fetch and execution of instruc­tions (Example 3-1). Consequently, all instructions (35)
execute in a single cycle (200 ns @ 20 MHz) e xcept f or
program branches.

The table below lists program memory (EPROM) and
data memory (RAM) for each PIC16C71X device.

The PIC16CXX can directly or indirectly address its
register files or data memory. All special function regis­ters, including the program counter, are mapped in the
data memory. The PIC16CXX has 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 programming with the
PIC16CXX simple yet efficient. In addition, the learning
curve is reduced significantly.

Device

Program

Memory

Data Memory

PIC16C710 512 x 14 36 x 8
PIC16C71 1K x 14 36 x 8
PIC16C711 1K x 14 68 x 8
PIC16C715 2K x 14 128 x 8

PIC16CXX devices contain an 8-bit ALU and working
register. The ALU is a general purpose arithmetic unit.
It performs arithmetic and Boolean functions between
the 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 operand instructions, the operand is
either the W register or a file register.

The W register is an 8-bit working register used f or 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 borro

w bit and a digit borrow out bit,
respectively, in subtraction. See the SUBLW and SUBWF
instructions for examples.

PIC16C71X

DS30272A-page 8



1997 Microchip Technology Inc.

FIGURE 3-1: PIC16C71X BLOCK DIAGRAM

EPROM

Program

Memory

13

Data Bus

8

14

Program

Bus

Instruction reg

Program Counter

8 Level Stack

(13-bit)

RAM

File

Registers

Direct Addr

7

RAM Addr

(1)

9

Addr MUX

Indirect

Addr

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

A/D

PORTA

PORTB

RB0/INT

RB7:RB1

8

8

Brown-out

Reset

(2)

Note 1: Higher order bits are from the STATUS register.

2: Brown-out Reset is not available on the PIC16C71.

Device Program Memory Data Memory (RAM)

PIC16C710
PIC16C71
PIC16C711
PIC16C715

512 x 14

1K x 14
1K x 14
2K x 14

36 x 8
36 x 8
68 x 8

128 x 8

RA4/T0CKI

RA3/AN3/VREF

RA2/AN2

RA1/AN1

RA0/AN0

8

3



1997 Microchip Technology Inc. DS30272A-page 9

PIC16C71X

TABLE 3-1: PIC16C710/71/711/715 PINOUT DESCRIPTION

Pin Name

DIP

Pin#

SSOP

Pin#

(4)

SOIC

Pin#

I/O/P
Type

Buffer

Type

Description

OSC1/CLKIN 16 18 16 I

ST/CMOS

(3)

Oscillator crystal input/external clock source input.

OSC2/CLKOUT 15 17 15 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 4 I/P ST Master clear (reset) input or programming voltage input. This pin is

an active low reset to the device.

PORTA is a bi-directional I/O port.
RA0/AN0 17 19 17 I/O TTL RA0 can also be analog input0
RA1/AN1 18 20 18 I/O TTL RA1 can also be analog input1
RA2/AN2 1 1 1 I/O TTL RA2 can also be analog input2
RA3/AN3/V

REF

2 2 2 I/O TTL RA3 can also be analog input3 or analog reference voltage

RA4/T0CKI 3 3 3 I/O ST RA4 can also be the cloc k input to the Timer0 module . Output is

open drain type.

PORTB is a bi-directional I/O port. PORTB can be software pro-

grammed for internal weak pull-up on all inputs.
RB0/INT 6 7 6 I/O TTL/ST

(1)

RB0 can also be the external interrupt pin.
RB1 7 8 7 I/O TTL
RB2 8 9 8 I/O TTL
RB3 9 10 9 I/O TTL
RB4 10 11 10 I/O TTL Interrupt on change pin.
RB5 11 12 11 I/O TTL Interrupt on change pin.
RB6 12 13 12 I/O TTL/ST

(2)

Interrupt on change pin. Serial programming clock.
RB7 13 14 13 I/O TTL/ST

(2)

Interrupt on change pin. Serial programming data.
V

SS

5 4, 6 5 P — Ground reference for logic and I/O pins.

V

DD

14 15, 16 14 P — Positive supply for logic and I/O pins.

Legend: I = input O = output I/O = input/output P = power

— = Not used TTL = TTL input ST = Schmitt Trigger input

Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.

2: This buffer is a Schmitt Trigger input when used in serial programming mode.
3: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.
4: The PIC16C71 is not available in SSOP package.

PIC16C71X

DS30272A-page 10



1997 Microchip Technology Inc.

3.1 Cloc

king Scheme/Instruction Cycle

The clock input (from OSC1) 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
is shown in Figure 3-2.

3.2 Instruction Flo

w/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 instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g. GOTO ) then
two cycles are required to complete the instruction
(Example 3-1).

A fetch cycle begins with the program counter (PC)
incrementing in Q1.

In the execution cycle, the f etched 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.

Tcy0 Tcy1 Tcy2 Tcy3 Tcy4 Tcy5

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 (Forced NOP)

Fetch 4 Flush

5. Instruction @ address SUB_1

Fetch SUB_1 Execute SUB_1



1997 Microchip Technology Inc. DS30272A-page 11

PIC16C71X

4.0 MEMORY ORGANIZATION

4.1 Pr

ogram Memory Organization

The PIC16C71X family has a 13-bit program counter
capable of addressing an 8K x 14 program memory
space. The amount of program memory available to
each device is listed below:

For those devices with less than 8K program memory,
accessing a location above the physically implemented
address will cause a wraparound.

The reset vector is at 0000h and the interrupt vector is
at 0004h.

FIGURE 4-1: PIC16C710 PROGRAM

MEMORY MAP AND STACK

Device

Program

Memory

Address Range

PIC16C710 512 x 14 0000h-01FFh
PIC16C71 1K x 14 0000h-03FFh
PIC16C711 1K x 14 0000h-03FFh
PIC16C715 2K x 14 0000h-07FFh

PC<12:0>

13

0000h

0004h
0005h

01FFh
0200h

1FFFh

Stack Level 1

Stack Level 8

Reset Vector

Interrupt Vector

On-chip Program

Memory

CALL, RETURN
RETFIE, RETLW

User Memory

Space

FIGURE 4-2: PIC16C71/711 PROGRAM

MEMORY MAP AND STACK

FIGURE 4-3: PIC16C715 PROGRAM

MEMORY MAP AND STACK

PC<12:0>

13

0000h

0004h
0005h

03FFh
0400h

1FFFh

Stack Level 1

Stack Level 8

Reset Vector

Interrupt Vector

On-chip Program

Memory

CALL, RETURN
RETFIE, RETLW

User Memory

Space

PC<12:0>

13

0000h

0004h
0005h

07FFh

1FFFh

Stack Level 1

Stack Level 8

Reset Vector

Interrupt Vector

On-chip Program

Memory

CALL, RETURN
RETFIE, RETLW

0800h

PIC16C71X

DS30272A-page 12  1997 Microchip Technology Inc.

4.2 Data Memory Organization

The data memory is partitioned into two Banks which
contain the General Purpose Registers and the Special
Function Registers. Bit RP0 is the bank select bit.

RP0 (STATUS<5>) = 1 → Bank 1
RP0 (STATUS<5>) = 0 → Bank 0
Each Bank extends up to 7Fh (128 bytes). The lower

locations of each Bank are reserved for the Special
Function Registers. Abo ve the Special Function Regis­ters are General Purpose Registers implemented as
static RAM. Both Bank 0 and Bank 1 contain special
function registers. Some "high use" special function
registers from Bank 0 are mirrored in Bank 1 for code
reduction and quicker access.

4.2.1 GENERAL PURPOSE REGISTER FILE
The register file can be accessed either directly , or indi-

rectly through the File Select Register FSR
(Section 4.5).

FIGURE 4-4: PIC16C710/71 REGISTER FILE

MAP

INDF

(1)

TMR0

PCL

ST A TUS

FSR
PORT A
PORTB

PCLA TH
INTCON

ADRES

ADCON0

INDF

(1)

OPTION

PCL

ST A TUS

FSR
TRISA
TRISB

PCLA TH
INTCON

ADCON1

00h
01h
02h
03h
04h
05h
06h
07h
08h

09h
0Ah
0Bh
0Ch

80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch

General
Purpose
Register

7Fh

FFh

Bank 0 Bank 1

File

Address

ADRES

2Fh
30h

AFh
B0h

File

Address

General
Purpose
Register

Mapped

in Bank 0

(3)

PCON

(2)

Unimplemented data memory locations, read

as '0'.

Note 1: Not a physical register.

2: The PCON register is not implemented on the

PIC16C71.

3: These locations are unimplemented in Bank 1.

Any access to these locations will access the
corresponding Bank 0 register.

 1997 Microchip Technology Inc. DS30272A-page 13

PIC16C71X

FIGURE 4-5: PIC16C711 REGISTER FILE

MAP

INDF

(1)

TMR0

PCL

STATUS

FSR

PORTA

PORTB

PCLATH
INTCON

ADRES

ADCON0

INDF

(1)

OPTION

PCL

STATUS

FSR
TRISA
TRISB

PCLATH
INTCON

ADCON1

00h
01h
02h
03h
04h
05h
06h
07h
08h

09h
0Ah
0Bh
0Ch

80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch

General
Purpose
Register

7Fh

FFh

Bank 0 Bank 1

File

Address

ADRES

4Fh
50h

CFh
D0h

File

Address

General
Purpose
Register

Mapped

in Bank 0

(2)

PCON

Unimplemented data memory locations, read

as '0'.

Note 1: Not a physical register.

2: These locations are unimplemented in Bank 1.

Any access to these locations will access the
corresponding Bank 0 register.

FIGURE 4-6: PIC16C715 REGISTER FILE

MAP

INDF

(1)

TMR0

PCL

STATUS

FSR

PORTA

PORTB

PCLATH
INTCON

PIR1

ADRES

ADCON0

INDF

(1)

OPTION

PCL

STATUS

FSR
TRISA
TRISB

PCLATH
INTCON

PIE1

PCON

ADCON1

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

General
Purpose
Register

7Fh

FFh

Bank 0 Bank 1

File

Address

BFh
C0h

File

Address

Unimplemented data memory locations, read

as '0'.

Note 1: Not a physical register.

PIC16C71X

DS30272A-page 14  1997 Microchip Technology Inc.

4.2.2 SPECIAL FUNCTION REGISTERS
The Special Function Registers are registers used by

the CPU and Peripheral Modules for controlling the
desired operation of the device. These registers are
implemented as static RAM.

The special function registers can be classified into two
sets (core and peripheral). Those registers associated
with the “core” functions are described in this section,
and those related to the operation of the peripheral fea­tures are described in the section of that peripheral
feature.

TABLE 4-1: PIC16C710/71/711 SPECIAL FUNCTION REGISTER SUMMARY

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on:

POR,
BOR

Value on all

other resets

(1)

Bank 0

00h

(3)

INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
01h TMR0 Timer0 module’s register xxxx xxxx uuuu uuuu
02h

(3)

PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
03h

(3)

STATUS

IRP

(5)

RP1

(5)

RP0 TO PD Z DC C 0001 1xxx 000q quuu

04h

(3)

FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
05h PORTA

— — — PORTA Data Latch when written: PORTA pins when read ---x 0000 ---u 0000
06h PORTB PORTB Data Latch when written: PORTB pins when read xxxx xxxx uuuu uuuu
07h — Unimplemented — —
08h ADCON0 ADCS1 ADCS0 (6) CHS1 CHS0 GO/DONE ADIF ADON 00-0 0000 00-0 0000

09h

(3)

ADRES A/D Result Register

xxxx xxxx uuuu uuuu

0Ah

(2,3)

PCLATH — — — Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000

0Bh

(3)

INTCON GIE ADIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u

Bank 1

80h

(3)

INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000

81h OPTION RBPU

INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

82h

(3)

PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000

83h

(3)

STATUS

IRP

(5)

RP1

(5)

RP0 TO PD Z DC C 0001 1xxx 000q quuu

84h

(3)

FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu

85h TRISA

— — — PORTA Data Direction Register ---1 1111 ---1 1111
86h TRISB PORTB Data Direction Control Register 1111 1111 1111 1111
87h

(4)

PCON — — — — — — POR BOR ---- --qq ---- --uu

88h ADCON1 — — — — — — PCFG1 PCFG0 ---- --00 ---- --00
89h

(3)

ADRES A/D Result Register

xxxx xxxx uuuu uuuu

8Ah

(2,3)

PCLATH — — — Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000

8Bh

(3)

INTCON GIE ADIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u

Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented read as '0'.

Shaded locations are unimplemented, read as ‘0’.

Note 1: Other (non power-up) resets include external reset through MCLR and Watchdog Timer Reset.

2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8> whose

contents are transferred to the upper byte of the program counter.
3: These registers can be addressed from either bank.
4: The PCON register is not physically implemented in the PIC16C71, read as ’0’.
5: The IRP and RP1 bits are reserved on the PIC16C710/71/711, always maintain these bits clear.
6: Bit5 of ADCON0 is a General Purpose R/W bit for the PIC16C710/711 only. For the PIC16C71, this bit is unimplemented,

read as '0'.

 1997 Microchip Technology Inc. DS30272A-page 15

PIC16C71X

TABLE 4-2: PIC16C715 SPECIAL FUNCTION REGISTER SUMMARY

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on:

POR,

BOR, PER

Value on all

other resets

(3)

Bank 0

00h

(1)

INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
01h TMR0 Timer0 module’s register xxxx xxxx uuuu uuuu
02h

(1)

PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
03h

(1)

STATUS IRP

(4)

RP1

(4)

RP0 TO PD Z DC C 0001 1xxx 000q quuu

04h

(1)

FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
05h PORTA — — — PORTA Data Latch when written: PORTA pins when read ---x 0000 ---u 0000
06h PORTB PORTB Data Latch when written: PORTB pins when read xxxx xxxx uuuu uuuu
07h — Unimplemented — —
08h — Unimplemented — —
09h — Unimplemented — —
0Ah

(1,2)

PCLATH — — — Write Buffer for the upper 5 bits of the Program Counter ---0 0000 ---0 0000
0Bh

(1)

INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 — ADIF — — — — — — -0-- ---- -0-- ----
0Dh — Unimplemented — —
0Eh — Unimplemented — —
0Fh — Unimplemented — —
10h — Unimplemented — —
11h — Unimplemented — —
12h — Unimplemented — —
13h — Unimplemented — —
14h — Unimplemented — —
15h — Unimplemented — —
16h — Unimplemented — —
17h — Unimplemented — —
18h — Unimplemented — —
19h — Unimplemented — —
1Ah — Unimplemented — —
1Bh — Unimplemented — —
1Ch — Unimplemented — —
1Dh — Unimplemented — —
1Eh ADRES A/D Result Register xxxx xxxx uuuu uuuu
1Fh ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE — ADON 0000 00-0 0000 00-0

Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented read as '0'.

Shaded locations are unimplemented, read as ‘0’.

Note 1: These registers can be addressed from either bank.

2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8> whose

contents are transferred to the upper byte of the program counter.
3: Other (non power-up) resets include external reset through MCLR and Watchdog Timer Reset.
4: The IRP and RP1 bits are reserved on the PIC16C715, always maintain these bits clear.

PIC16C71X

DS30272A-page 16  1997 Microchip Technology Inc.

Bank 1

80h

(1)

INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 0000 0000
81h OPTION RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
82h

(1)

PCL Program Counter's (PC) Least Significant Byte 0000 0000 0000 0000
83h

(1)

STATUS IRP

(4)

RP1

(4)

RP0 TO PD Z DC C 0001 1xxx 000q quuu

84h

(1)

FSR Indirect data memory address pointer xxxx xxxx uuuu uuuu
85h TRISA — — PORTA Data Direction Register --11 1111 --11 1111
86h TRISB PORTB Data Direction Register 1111 1111 1111 1111
87h — Unimplemented — —
88h — Unimplemented — —
89h — Unimplemented — —
8Ah

(1,2)

PCLATH — — — Write Buffer for the upper 5 bits of the PC ---0 0000 ---0 0000
8Bh

(1)

INTCON GIE PEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
8Ch PIE1 — ADIE — — — — — — -0-- ---- -0-- ----
8Dh — Unimplemented — —
8Eh PCON MPEEN — — — — PER POR BOR u--- -1qq u--- -1uu
8Fh — Unimplemented — —
90h — Unimplemented — —
91h — Unimplemented — —
92h — Unimplemented — —
93h — Unimplemented — —
94h — Unimplemented — —
95h — Unimplemented — —
96h — Unimplemented — —
97h — Unimplemented — —
98h — Unimplemented — —
99h — Unimplemented — —
9Ah — Unimplemented — —
9Bh — Unimplemented — —
9Ch — Unimplemented — —
9Dh — Unimplemented — —
9Eh — Unimplemented — —
9Fh ADCON1 — — — — — — PCFG1 PCFG0 ---- --00 ---- --00

TABLE 4-2: PIC16C715 SPECIAL FUNCTION REGISTER SUMMARY (Cont.’d)

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on:

POR,

BOR, PER

Value on all

other resets

(3)

Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented read as '0'.

Shaded locations are unimplemented, read as ‘0’.

Note 1: These registers can be addressed from either bank.

2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8> whose

contents are transferred to the upper byte of the program counter.
3: Other (non power-up) resets include external reset through MCLR and Watchdog Timer Reset.
4: The IRP and RP1 bits are reserved on the PIC16C715, always maintain these bits clear.

 1997 Microchip Technology Inc. DS30272A-page 17

PIC16C71X

4.2.2.1 STATUS REGISTER

The STATUS register, shown in Figure 4-7, 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, as with 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. Furthermore, the T

O and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.

For example, CLRF STATUS will clear the upper-three
bits and set the Z bit. This leaves the ST ATUS register
as 000u u1uu (where u = unchanged).

Applicable Devices 710 71 711 715

It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions are used to alter the
STATUS register because these instructions do not
affect the Z, C or DC bits from the STA TUS register . For
other instructions, not affecting any status bits, see the
"Instruction Set Summary."

Note 1: For those devices that do not use bits IRP

and RP1 (STATUS<7:6>), maintain these
bits clear to ensure upward compatibility
with future products.

Note 2: The C and DC bits operate as a borro

w
and digit borrow bit, respectively, in sub­traction. See the SUBLW and SUBWF
instructions for examples.

FIGURE 4-7: STATUS REGISTER (ADDRESS 03h, 83h)

R/W-0 R/W-0 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
U = Unimplemented bit,
read as ‘0’

- n = Value 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)

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

bit 4: T

O: 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/borro

w 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/borro

w 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 borro

w 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.

PIC16C71X

DS30272A-page 18  1997 Microchip Technology Inc.

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 INT Interrupt,
TMR0, and the weak pull-ups on PORTB.

Applicable Devices 710 71 711 715

Note: To achieve a 1:1 prescaler assignment for

the TMR0 register, assign the prescaler to
the Watchdog Timer by setting bit PSA
(OPTION<3>).

FIGURE 4-8: OPTION REGISTER (ADDRESS 81h, 181h)

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
U = Unimplemented bit,

read as ‘0’

- 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

 1997 Microchip Technology Inc. DS30272A-page 19

PIC16C71X

4.2.2.3 INTCON REGISTER

The INTCON Register is a readable and writable regis­ter which contains various enable and flag bits for the
TMR0 register overflow, RB Port change and Exter nal
RB0/INT pin interrupts.

Applicable Devices 710 71 711 715

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 4-9: INTCON REGISTER (ADDRESS 0Bh, 8Bh)

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x

GIE ADIE T0IE INTE RBIE T0IF INTF RBIF R = Readable bit

W = Writable bit
U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

bit7 bit0

bit 7: GIE:

(1)

Global Interrupt Enable bit

1 = Enables all un-masked interrupts
0 = Disables all interrupts

bit 6: ADIE: A/D Converter Interrupt Enable bit

1 = Enables A/D interrupt
0 = Disables A/D interrupt

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 = 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

Note 1: For the PIC16C71, if an interrupt occurs while the GIE bit is being cleared, the GIE bit may be uninten-

tionally re-enabled by the RETFIE instruction in the user’ s Interrupt Service Routine. Ref er to Section 8.5
for a detailed description.

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>). User software should ensure the appropriate interrupt flag bits are clear prior to
enabling an interrupt.

PIC16C71X

DS30272A-page 20  1997 Microchip Technology Inc.

4.2.2.4 PIE1 REGISTER

This register contains the individual enable bits for the
Peripheral interrupts.

Applicable Devices 710 71 711 715

Note: Bit PEIE (INTCON<6>) must be set to

enable any peripheral interrupt.

FIGURE 4-10: PIE1 REGISTER (ADDRESS 8Ch)

U-0 R/W-0 U-0 U-0 U-0 U-0 U-0 U-0

— ADIE — — — — — — R = Readable bit

W = Writable bit
U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

bit7 bit0

bit 7: Unimplemented: Read as '0'
bit 6: ADIE: A/D Converter Interrupt Enable bit

1 = Enables the A/D interrupt
0 = Disables the A/D interrupt

bit 5-0: Unimplemented: Read as '0'

 1997 Microchip Technology Inc. DS30272A-page 21

PIC16C71X

4.2.2.5 PIR1 REGISTER

This register contains the individual flag bits for the
Peripheral interrupts.

Applicable Devices 710 71 711 715

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>). User soft­ware should ensure the appropriate inter­rupt flag bits are clear prior to enabling an
interrupt.

FIGURE 4-11: PIR1 REGISTER (ADDRESS 0Ch)

U-0 R/W-0 U-0 U-0 U-0 U-0 U-0 U-0

— ADIF — — — — — — R = Readable bit

W = Writable bit
U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

bit7 bit0

bit 7: Unimplemented: Read as '0'
bit 6: ADIF: A/D Converter Interrupt Flag bit

1 = An A/D conversion completed
0 = The A/D conversion is not complete

bit 5-0: Unimplemented: Read as '0'

PIC16C71X

DS30272A-page 22  1997 Microchip Technology Inc.

4.2.2.6 PCON REGISTER

The Power Control (PCON) register contains a flag bit
to allow differentiation between a Power-on Reset
(POR) to an external MCLR

Reset or WDT Reset.
Those devices with brown-out detection circuitry con­tain an additional bit to differentiate a Brown-out Reset
(BOR) condition from a Power-on Reset condition. For
the PIC16C715 the PCON register also contains status
bits MPEEN and PER. MPEEN reflects the v alue of the
MPEEN bit in the configuration word. PER indicates a
parity error reset has occurred.

Applicable Devices 710 71 711 715

Note: BOR is unknown on Power-on Reset. It

must then be set by the user and checked
on subsequent resets to see if BOR

is
clear, indicating a brown-out has occurred.
The BOR

status bit is a don't care and is
not necessarily predictable if the brown-out
circuit is disabled (by clearing the BODEN
bit in the Configuration word).

FIGURE 4-12: PCON REGISTER (ADDRESS 8Eh), PIC16C710/711

FIGURE 4-13: PCON REGISTER (ADDRESS 8Eh), PIC16C715

U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-q

— — — — — — POR BOR 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 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)

bit 0: BOR

: Brown-out Reset Status bit
1 = No Brown-out Reset occurred
0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs)

R-U U-0 U-0 U-0 U-0 R/W-1 R/W-0 R/W-q

MPEEN — — — — PER POR BOR

(1)

R = Readable bit
W = Writable bit
U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

bit7 bit0

bit 7: MPEEN: Memory Parity Error Circuitry Status bit

Reflects the value of configuration word bit, MPEEN

bit 6-3: Unimplemented: Read as '0'
bit 2: PER

: Memory Parity Error Reset Status bit
1 = No Error occurred
0 = Program Memory Fetch Parity Error occurred (must be set in software after a Parity Error Reset)

bit 1: POR

: Power-on Reset Status bit
1 = No Power-on Reset occurred
0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)

bit 0: BOR

: Brown-out Reset Status bit
1 = No Brown-out Reset occurred
0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs)

 1997 Microchip Technology Inc. DS30272A-page 23

PIC16C71X

4.3 PCL and PCLATH

The program counter (PC) is 13-bits wide. The lo w byte
comes from the PCL register, which is a readable and
writable register. The upper bits (PC<12:8>) are not
readable, but are indirectly writable through the
PCLATH register. On any reset, the upper bits of the
PC will be cleared. Figure 4-14 shows the two situa­tions for the loading of the PC. The upper example in
the figure shows how the PC is loaded on a write to
PCL (PCLA TH<4:0> → PCH). The low er example in the
figure shows how the PC is loaded during a CALL or
GOTO instruction (PCLATH<4:3> → PCH).

FIGURE 4-14: LOADING OF PC IN

DIFFERENT SITUATIONS

4.3.1 COMPUTED GOTO
A computed GOTO is accomplished by adding an off-

set to the program counter (ADDWF PCL). When doing a
table read using a computed GOTO method, care
should be exercised if the tab le location crosses a PCL
memory boundary (each 256 byte block). Refer to the
application note

“Implementing a Table Read"

(AN556).

PC

12 8 7 0

5

PCLA TH<4:0>

PCLA TH

Instr

uction with

ALU

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 PIC16CXX family has an 8 lev el deep x 13-bit wide

hardware stack. 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 POPed in the event of a
RETURN, RETLW or a RETFIE instruction execution.
PCLATH is not affected by a PUSH or POP operation.

The stack operates as a circular buff er . This means that
after the stack has been PUSHed eight times, the ninth
push overwrites the value that was stored from the first
push. The tenth push overwrites the second push (and
so on).

4.4 Program Memory Paging

The PIC16C71X devices ignore both paging bits
(PCLATH<4:3>, which are used to access program
memory when more than one page is available. The
use of PCLATH<4:3> as general purpose read/write
bits for the PIC16C71X is not recommended since this
may affect upward compatibility with future products.

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 the vectoring to an interrupt
address.

PIC16C71X

DS30272A-page 24  1997 Microchip Technology Inc.

Example 4-1 shows the calling of a subroutine in
page 1 of the program memory. This e xample assumes
that PCLA TH is sa ved and restored by the interrupt ser­vice routine (if interrupts are used).

EXAMPLE 4-1: CALL OF A SUBROUTINE IN

PAGE 1 FROM PAGE 0

ORG 0x500
BSF PCLATH,3 ;Select page 1 (800h-FFFh)
BCF PCLATH,4 ;Only on >4K devices
CALL SUB1_P1 ;Call subroutine in
: ;page 1 (800h-FFFh)
:
:
ORG 0x900
SUB1_P1: ;called subroutine
: ;page 1 (800h-FFFh)
:
RETURN ;return to Call subroutine
;in page 0 (000h-7FFh)

4.5 Indirect Addressing, INDF and FSR
Registers

The INDF register is not a physical register . Addressing
the INDF register will cause indirect addressing.

Indirect addressing is possible by using the INDF reg­ister. Any instruction using the INDF register actually
accesses the register pointed to by the File Select Reg­ister, FSR. Reading the INDF register itself indirectly
(FSR = '0') will read 00h. Writing to the INDF register
indirectly results in a no-operation (although status bits
may be affected). An effective 9-bit address is obtained
by concatenating the 8-bit FSR register and the IRP bit
(STATUS<7>), as shown in Figure 4-15. However, IRP
is not used in the PIC16C71X devices.

A simple program to clear RAM locations 20h-2Fh
using indirect addressing is shown in Example 4-2.

EXAMPLE 4-2: INDIRECT ADDRESSING

movlw 0x20 ;initialize pointer
movwf FSR ;to RAM
NEXT clrf INDF ;clear INDF register
incf FSR,F ;inc pointer
btfss FSR,4 ;all done?
goto NEXT ;no clear next
CONTINUE
: ;yes continue

FIGURE 4-15: DIRECT/INDIRECT ADDRESSING

For register file map detail see 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

RP1:RP0 6

0

from opcode

IRP

(1)

FSR register

7

0

bank select

location select

00 01 10 11

Bank 0 Bank 1 Bank 2 Bank 3

FFh

80h

7Fh

00h

17Fh

100h

1FFh

180h

Not

Used

 1997 Microchip Technology Inc. DS30272A-page 25

PIC16C71X

5.0 I/O PORTS

Some pins for these I/O ports are multiplexed with an
alternate function for the peripheral features on the
device. In general, when a peripheral is enabled, that
pin may not be used as a general purpose I/O pin.

5.1 PORTA and TRISA Registers

PORTA is a 5-bit latch.
The RA4/T0CKI pin is a Schmitt Trigger input and an

open drain output. All other RA port pins have TTL
input levels and full CMOS output drivers . All pins have
data direction bits (TRIS registers) which can configure
these pins as output or input.

Setting a TRISA register bit puts the corresponding out­put driver in a hi-impedance mode. Clearing a bit 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 write to the port latch. All
write operations are read-modify-write operations.
Therefore a write to a port implies that the port pins are
read, this value is modified, and then written to the port
data latch.

Pin RA4 is multiplexed with the Timer0 module clock
input to become the RA4/T0CKI pin.

Other PORTA pins are multiplexed with analog inputs
and analog V

REF input. The operation of each pin is

selected by clearing/setting the control bits in the
ADCON1 register (A/D Control Register1).

The TRISA register controls the direction of the RA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.

EXAMPLE 5-1: INITIALIZING PORTA

BCF STATUS, RP0 ;
CLRF PORTA ; Initialize PORTA by
; clearing output
; data latches
BSF STATUS, RP0 ; Select Bank 1
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISA ; Set RA<3:0> as inputs
; RA<4> as outputs
; TRISA<7:5> are always
; read as '0'.

Applicable Devices 710 71 711 715

Note: On a Power-on Reset, these pins are con-

figured as analog inputs and read as '0'.

FIGURE 5-1: BLOCK DIAGRAM OF

RA3:RA0 PINS

FIGURE 5-2: BLOCK DIAGRAM OF RA4/

T0CKI PIN

Data
bus

QD

Q

CK

QD

Q

CK

Q D

EN

P

N

WR
Port

WR
TRIS

Data Latch

TRIS Latch

RD TRIS

RD PORT

V

SS

VDD

I/O pin

(1)

Note 1: I/O pins have protection diodes to VDD and

VSS.

Analog
input
mode

TTL
input
buffer

To A/D Converter

Data
bus

WR
PORT

WR
TRIS

RD PORT

Data Latch

TRIS Latch

RD TRIS

Schmitt
Trigger
input
buffer

N

V

SS

I/O pin

(1)

TMR0 clock input

Note 1: I/O pin has protection diodes to VSS only.

QD

Q

CK

QD

Q

CK

EN

Q D

EN

PIC16C71X

DS30272A-page 26  1997 Microchip Technology Inc.

TABLE 5-1: PORTA FUNCTIONS

TABLE 5-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

Name Bit# Buffer Function

RA0/AN0 bit0 TTL Input/output or analog input
RA1/AN1 bit1 TTL Input/output or analog input
RA2/AN2 bit2 TTL Input/output or analog input
RA3/AN3/V

REF bit3 TTL Input/output or analog input/VREF

RA4/T0CKI bit4 ST Input/output or external clock input for Timer0

Output is open drain type

Legend: TTL = TTL input, 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,
BOR

Value on all

other resets

05h PORTA — — — RA4 RA3 RA2 RA1 RA0 ---x 0000 ---u 0000
85h TRISA — — — PORTA Data Direction Register ---1 1111 ---1 1111
9Fh ADCON1 — — — — — — PCFG1 PCFG0 ---- --00 ---- --00

Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by PORTA.

 1997 Microchip Technology Inc. DS30272A-page 27

PIC16C71X

5.2 PORTB and TRISB Registers

PORTB is an 8-bit wide bi-directional port. The corre­sponding data direction register is TRISB. Setting a bit
in the TRISB register puts the corresponding output
driver in a hi-impedance input mode. Clearing a bit in
the TRISB register puts the contents of the output latch
on the selected pin(s).

EXAMPLE 5-2: INITIALIZING PORTB

BCF STATUS, RP0 ;
CLRF PORTB ; Initialize PORTB by
; clearing output
; data latches
BSF STATUS, RP0 ; Select Bank 1
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISB ; Set RB<3:0> as inputs
; RB<5:4> as outputs
; RB<7:6> as inputs

Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is
performed by clearing bit RBPU

(OPTION<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are dis­abled on a Power-on Reset.

FIGURE 5-3: BLOCK DIAGRAM OF

RB3:RB0 PINS

Data Latch

RBPU

(2)

P

V

DD

QD

CK

QD

CK

Q D

EN

Data bus

WR Port

WR TRIS

RD TRIS

RD Port

weak
pull-up

RD Port

RB0/INT

I/O
pin

(1)

TTL
Input
Buffer

Note 1: I/O pins have diode protection to V

DD and VSS.

2: TRISB = ’1’ enables weak pull-up if

RBPU

= ’0’ (OPTION<7>).

Schmitt Trigger
Buffer

TRIS Latch

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. an y 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 RB Port Change Inter­rupt with flag bit RBIF (INTCON<0>).

This interrupt can wake the device from SLEEP. The
user, in the interrupt service routine, can clear the inter­rupt in the following 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 keypad and make it possible for
wake-up on key-depression. Refer to the Embedded
Control Handbook,

"Implementing Wake-Up on Key

Stroke"

(AN552).

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: For the PIC16C71

if a change on the I/O pin should occur
when the read operation is being executed
(start of the Q2 cycle), then interrupt flag bit
RBIF may not get set.

PIC16C71X

DS30272A-page 28  1997 Microchip Technology Inc.

FIGURE 5-4: BLOCK DIAGRAM OF

RB7:RB4 PINS
(PIC16C71)

Data Latch

From other

RBPU

(2)

P

V

DD

I/O

QD

CK

QD

CK

Q D

EN

Q D

EN

Data bus

WR Port

WR TRIS

Set RBIF

TRIS Latch

RD TRIS

RD Port

RB7:RB4 pins

weak
pull-up

RD Port

Latch

TTL
Input
Buffer

pin

(1)

ST

Buffer

RB7:RB6 in serial programming mode
Note 1: I/O pins have diode protection to VDD and VSS.

2: TRISB = ’1’ enables weak pull-up if

RBPU

= ’0’ (OPTION<7>).

FIGURE 5-5: BLOCK DIAGRAM OF

RB7:RB4 PINS
(PIC16C710/711/715)

Data Latch

From other

RBPU

(2)

P

V

DD

I/O

QD

CK

QD

CK

Q D

EN

Q D

EN

Data bus

WR Port

WR TRIS

Set RBIF

TRIS Latch

RD TRIS

RD Port

RB7:RB4 pins

weak
pull-up

RD Port

Latch

TTL
Input
Buffer

pin

(1)

ST

Buffer

RB7:RB6 in serial programming mode

Q3

Q1

Note 1: I/O pins have diode protection to V

DD and VSS.

2: TRISB = ’1’ enables weak pull-up if

RBPU

= ’0’ (OPTION<7>).

TABLE 5-3: PORTB FUNCTIONS

Name Bit# Buffer Function

RB0/INT bit0 TTL/ST

(1)

Input/output pin 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.
RB7 bit7 TTL/ST

(2)

Input/output pin (with interrupt on change). Internal software programmable

weak pull-up. Serial programming data.
Legend: TTL = TTL input, ST = Schmitt Trigger input

Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.

2: This buffer is a Schmitt Trigger input when used in serial programming mode.

 1997 Microchip Technology Inc. DS30272A-page 29

PIC16C71X

TABLE 5-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Value on:

POR,

BOR

Value on all

other resets

06h, 106h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu
86h, 186h TRISB PORTB Data Direction Register 1111 1111 1111 1111
81h, 181h OPTION RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.

PIC16C71X

DS30272A-page 30  1997 Microchip Technology Inc.

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 port with both inputs and
outputs defined. For example, a BSF operation on bit5
of PORTB will cause all eight bits of PORTB 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 bi-directional 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 rewritten to the data latch of this particular
pin, overwriting the previous content. As long as the pin
stays in the input mode, no problem occurs. However,
if bit0 is switched to an output, 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 port, the value of the port pins
is read, the desired operation is done to this value, and
this value is then written to the port latch.

Example 5-3 shows the effect of two sequential read­modify-write instructions on an I/O port.

EXAMPLE 5-3: READ-MODIFY-WRITE

INSTRUCTIONS ON AN I/O
PORT

;Initial PORT settings: PORTB<7:4> Inputs
; PORTB<3:0> Outputs
;PORTB<7:6> have external pull-ups 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 ppp. The 2nd BCF
;caused RB7 to be latched as the pin value
;(high).

A pin actively outputting a Low or High should not be
driven from external devices at the same time in order
to change the level on this pin (“wired-or”, “wired-and”).
The resulting high output currents may damage the
chip.

5.3.2 SUCCESSIVE OPERATIONS 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 5-6). 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 executed. Otherwise, the
previous state of that pin may be read into the CPU
rather than the new state. When in doubt, it is better to
separate these instructions with a NOP or another
instruction not accessing this I/O port.

FIGURE 5-6: SUCCESSIVE I/O OPERATION

PC PC + 1 PC + 2

PC + 3

Q1 Q2

Q3

Q4

Q1 Q2

Q3

Q4

Q1 Q2

Q3

Q4

Q1 Q2

Q3

Q4

Instruction

fetched

RB7:RB0

MOVWF PORTB

write to
PORTB

NOP

Port pin
sampled here

NOP

MOVF PORTB,W

Instruction

executed

MOVWF PORTB

write to
PORTB

NOP

MOVF PORTB,W

PC

TPD

Note:
This example shows a write to PORTB

followed by a read from PORTB.
Note that:
data setup time = (0.25TCY - TPD)
where TCY = instruction cycle

TPD = propagation delay

Therefore, at higher clock frequencies,
a write followed by a read may be
problematic.