PIC16F870
PIC16F870/871
Data Sheet
28/40-Pin, 8-Bit CMOS
FLASH Microcontrollers
 2003 Microchip Technology Inc.
DS30569B
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is intended through suggestion 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and may be superseded by updates.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 Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
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Trademarks
The Microchip name and logo, the Microchip logo, KEELOQ,
MPLAB, PIC, PICmicro, PICSTART, PRO MATE and
PowerSmart are registered trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL
and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Accuron, Application Maestro, dsPIC, dsPICDEM,
dsPICDEM.net, ECONOMONITOR, FanSense, FlexROM,
fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC,
microPort, Migratable Memory, MPASM, MPLIB, MPLINK,
MPSIM, PICC, PICkit, PICDEM, PICDEM.net, PowerCal,
PowerInfo, PowerMate, PowerTool, rfLAB, rfPIC, Select
Mode, SmartSensor, SmartShunt, SmartTel and Total
Endurance are trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2003, 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 Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro® 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of development
systems is ISO 9001 certified.
DS30569B-page ii
 2003 Microchip Technology Inc.
PIC16F870/871
28/40-Pin, 8-Bit CMOS FLASH Microcontrollers
• PIC16F870
• PIC16F871
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
• 2K x 14 words of FLASH Program Memory
128 x 8 bytes of Data Memory (RAM)
64 x 8 bytes of EEPROM Data Memory
• Pinout compatible to the PIC16CXXX 28 and
40-pin devices
• Interrupt capability (up to 11 sources)
• 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 FLASH/EEPROM
technology
• Fully static design
• In-Circuit Serial Programming (ICSP) via
two pins
• Single 5V In-Circuit Serial Programming capability
• In-Circuit Debugging via two pins
• Processor read/write access to program memory
• Wide operating voltage range: 2.0V to 5.5V
• High Sink/Source Current: 25 mA
• Commercial and Industrial temperature ranges
• Low power consumption:
- < 1.6 mA typical @ 5V, 4 MHz
- 20 µA typical @ 3V, 32 kHz
- < 1 µA typical standby current
 2003 Microchip Technology Inc.
Pin Diagram
PDIP
MCLR/VPP/THV
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKI
OSC2/CLKO
RC0/T1OSO/T1CKI
RC1/T1OSI
RC2/CCP1
RC3
RD0/PSP0
RD1/PSP1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
PIC16F871
Devices Included in this Data Sheet:
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
RB7/PGD
RB6/PGC
RB5
RB4
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC7/RX/DT
RC6/TX/CK
RC5
RC4
RD3/PSP3
RD2/PSP2
Peripheral Features:
• Timer0: 8-bit timer/counter with 8-bit prescaler
• Timer1: 16-bit timer/counter with prescaler,
can be incremented during SLEEP via external
crystal/clock
• Timer2: 8-bit timer/counter with 8-bit period
register, prescaler and postscaler
• One Capture, Compare, PWM module
- Capture is 16-bit, max. resolution is 12.5 ns
- Compare is 16-bit, max. resolution is 200 ns
- PWM max. resolution is 10-bit
• 10-bit multi-channel Analog-to-Digital converter
• Universal Synchronous Asynchronous Receiver
Transmitter (USART/SCI) with 9-bit address
detection
• Parallel Slave Port (PSP) 8-bits wide, with
external RD, WR and CS controls (40/44-pin only)
• Brown-out detection circuitry for
Brown-out Reset (BOR)
DS30569B-page 1
PIC16F870/871
Pin Diagrams
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RB7/PGD
RB6/PGC
RB5
RB4
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5
RC4
6
5
4
3
2
1
44
43
42
41
40
PLCC
RA3/AN3/VREF+
RA2/AN2/VREFRA1/AN1
RA0/AN0
MCLR/VPP/THV
NC
RB7/PGD
RB6/PGC
RB5
RB4
NC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
MCLR/VPP/THV
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4
VSS
OSC1/CLKI
OSC2/CLKO
RC0/T1OSO/T1CKI
RC1/T1OSI
RC2/CCP1
RC3
PIC16F870
DIP, SOIC, SSOP
18
19
20
21
22
23
24
25
26
27
282
PIC16F871
39
38
37
36
35
34
33
32
31
30
9
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC7/RX/DT
44
43
42
41
40
39
38
37
36
35
34
TQFP
7
8
9
10
11
12
13
14
15
16
17
RC1/T1OSI
RC2/CCP1
RC3
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RC4
RC5
RC6/TX/CK
NC
RC6/TX/CK
RC5
RC4
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3
RC2/CCP1
RC1/T1OSI
NC
RA4/T0CKI
RA5/AN4
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKI
OSC2/CLKO
RC0/T1OSO/T1CK1
NC
PIC16F871
33
32
31
30
29
28
27
26
25
24
23
12
13
14
15
16
17
18
19
20
21
22
1
2
3
4
5
6
7
8
9
10
11
NC
RC0/T1OSO/T1CKI
OSC2/CLKO
OSC1/CLKI
VSS
VDD
RE2/CS/AN7
RE1/WR/AN6
RE0/RD/AN5
RA5/AN4
RA4/T0CKI
NC
NC
RB4
RB5
RB6/PGC
RB7/PGD
MCLR/VPP/THV
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RC7/RX/DT
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
VSS
VDD
RB0/INT
RB1
RB2
RB3/PGM
DS30569B-page 2
 2003 Microchip Technology Inc.
PIC16F870/871
Key Features
PICmicroTM Mid-Range MCU Family Reference Manual
(DS33023)
PIC16F870
PIC16F871
Operating Frequency
DC - 20 MHz
DC - 20 MHz
RESETS (and Delays)
POR, BOR (PWRT, OST)
POR, BOR (PWRT, OST)
FLASH Program Memory (14-bit words)
2K
2K
Data Memory (bytes)
128
128
EEPROM Data Memory
64
64
Interrupts
10
11
I/O Ports
Ports A,B,C
Ports A,B,C,D,E
3
3
Timers
Capture/Compare/PWM modules
Serial Communications
Parallel Communications
10-bit Analog-to-Digital Module
Instruction Set
 2003 Microchip Technology Inc.
1
1
USART
USART
—
PSP
5 input channels
8 input channels
35 Instructions
35 Instructions
DS30569B-page 3
PIC16F870/871
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 5
2.0 Memory Organization ................................................................................................................................................................. 11
3.0 Data EEPROM and Flash Program Memory.............................................................................................................................. 27
4.0 I/O Ports ..................................................................................................................................................................................... 33
5.0 Timer0 Module ........................................................................................................................................................................... 45
6.0 Timer1 Module ........................................................................................................................................................................... 49
7.0 Timer2 Module ........................................................................................................................................................................... 53
8.0 Capture/Compare/PWM Modules .............................................................................................................................................. 55
9.0 Addressable Universal Synchronous Asynchronous Receiver Transmitter (USART)................................................................ 61
10.0 Analog-to-Digital (A/D) Converter Module .................................................................................................................................. 79
11.0 Special Features of the CPU ...................................................................................................................................................... 87
12.0 Instruction Set Summary .......................................................................................................................................................... 103
13.0 Development Support............................................................................................................................................................... 111
14.0 Electrical Characteristics .......................................................................................................................................................... 117
15.0 DC and AC Characteristics Graphs and Tables ....................................................................................................................... 137
16.0 Packaging Information.............................................................................................................................................................. 149
Appendix A: Revision History............................................................................................................................................................. 157
Appendix B: Device Differences......................................................................................................................................................... 157
Appendix C: Conversion Considerations ........................................................................................................................................... 158
Appendix D: Migration from Mid-Range to Enhanced Devices .......................................................................................................... 158
Appendix E: Migration from High-End to Enhanced Devices............................................................................................................. 159
Index .................................................................................................................................................................................................. 161
On-Line Support................................................................................................................................................................................. 167
Systems Information and Upgrade Hot Line ...................................................................................................................................... 167
Reader Response .............................................................................................................................................................................. 168
PIC16F870/871 Product Identification System .................................................................................................................................. 169
TO OUR VALUED CUSTOMERS
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We welcome your feedback.
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The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
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DS30569B-page 4
 2003 Microchip Technology Inc.
PIC16F870/871
1.0
DEVICE OVERVIEW
There are two devices (PIC16F870 and PIC16F871)
covered by this data sheet. The PIC16F870 device
comes in a 28-pin package and the PIC16F871 device
comes in a 40-pin package. The 28-pin device does not
have a Parallel Slave Port implemented.
This document contains device specific information.
Additional information may be found in the PICmicroTM
Mid-Range
MCU
Family
Reference Manual
(DS33023), which may be obtained from your local
Microchip Sales Representative or downloaded from
the Microchip web site. The Reference Manual should
be considered a complementary document to this data
sheet, and is highly recommended reading for a better
understanding of the device architecture and operation
of the peripheral modules.
FIGURE 1-1:
The following two figures are device block diagrams
sorted by pin number: 28-pin for Figure 1-1 and 40-pin
for Figure 1-2. The 28-pin and 40-pin pinouts are listed
in Table 1-1 and Table 1-2, respectively.
PIC16F870 BLOCK DIAGRAM
Device
Program FLASH
Data Memory
Data EEPROM
PIC16F870
2K
128 Bytes
64 Bytes
13
FLASH
Program
Memory
14
PORTA
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4
RAM
File
Registers
8 Level Stack
(13-bit)
Program
Bus
8
Data Bus
Program Counter
RAM Addr (1)
PORTB
9
Addr MUX
Instruction reg
Direct Addr
7
8
Indirect
Addr
FSR reg
STATUS reg
8
3
Power-up
Timer
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKI
OSC2/CLKO
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Brown-out
Reset
In-Circuit
Debugger
MUX
ALU
PORTC
RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
RC0/T1OSO/T1CKI
RC1/T1OSI
RC2/CCP1
RC3
RC4
RC5
RC6/TX/CK
RC7/RX/DT
8
W reg
Low-Voltage
Programming
MCLR
Timer0
Timer1
Data EEPROM
CCP1
Note 1:
VDD, VSS
Timer2
10-bit A/D
USART
Higher order bits are from the STATUS register.
 2003 Microchip Technology Inc.
DS30569B-page 5
PIC16F870/871
FIGURE 1-2:
PIC16F871 BLOCK DIAGRAM
Device
Program FLASH
Data Memory
Data EEPROM
PIC16F871
2K
128 Bytes
64 Bytes
13
Program
Memory
14
PORTA
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4
RAM
File
Registers
8 Level Stack
(13-bit)
Program
Bus
8
Data Bus
Program Counter
FLASH
RAM Addr (1)
PORTB
9
Addr MUX
Instruction reg
Direct Addr
7
8
Indirect
Addr
FSR reg
STATUS reg
8
3
Power-up
Timer
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKI
OSC2/CLKO
Oscillator
Start-up Timer
Power-on
Reset
PORTC
RC0/T1OSO/T1CKI
RC1/T1OSI
RC2/CCP1
RC3
RC4
RC5
RC6/TX/CK
RC7/RX/DT
MUX
ALU
8
Watchdog
Timer
Brown-out
Reset
RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
PORTD
W reg
RD7/PSP7:RD0/PSP0
In-Circuit
Debugger
Low-Voltage
Programming
PORTE
RE0/RD/AN5
RE1/WR/AN6
MCLR
Timer0
Timer1
Data EEPROM
CCP1
Note 1:
VDD, VSS
Timer2
Parallel Slave Port
RE2/CS/AN7
10-bit A/D
USART
Higher order bits are from the STATUS register.
DS30569B-page 6
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 1-1:
PIC16F870 PINOUT DESCRIPTION
DIP
Pin#
SOIC
Pin#
I/O/P
Type
OSC1/CLKI
9
9
I
OSC2/CLKO
10
10
O
—
Oscillator crystal output. Connects to crystal or resonator in
Crystal Oscillator mode. In RC mode, the OSC2 pin outputs
CLKO, which has 1/4 the frequency of OSC1, and denotes the
instruction cycle rate.
MCLR/VPP/THV
1
1
I/P
ST
Master Clear (Reset) input or programming voltage input or High
Voltage Test mode control. This pin is an active low RESET to the
device.
Pin Name
Buffer
Type
Description
ST/CMOS(3) Oscillator crystal input/external clock source input.
PORTA is a bi-directional I/O port.
RA0/AN0
2
2
I/O
TTL
RA1/AN1
3
3
I/O
TTL
RA0 can also be analog input 0.
RA1 can also be analog input 1.
RA2/AN2/VREF-
4
4
I/O
TTL
RA2 can also be analog input 2 or negative analog reference
voltage.
RA3/AN3/VREF+
5
5
I/O
TTL
RA3 can also be analog input 3 or positive analog reference
voltage.
RA4/T0CKI
6
6
I/O
ST/OD
RA4 can also be the clock input to the Timer0 module. Output
is open drain type.
RA5/AN4
7
7
I/O
TTL
RA5 can also be analog input 4.
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-up on all inputs.
RB0/INT
21
21
I/O
TTL/ST(1)
RB1
22
22
I/O
TTL
RB2
23
23
I/O
TTL
RB3/PGM
24
24
I/O
TTL/ST(1)
RB4
25
25
I/O
TTL
Interrupt-on-change pin.
Interrupt-on-change pin.
RB0 can also be the external interrupt pin.
RB3 can also be the low voltage programming input.
RB5
26
26
I/O
TTL
RB6/PGC
27
27
I/O
TTL/ST(2)
Interrupt-on-change pin or In-Circuit Debugger pin. Serial
programming clock.
RB7/PGD
28
28
I/O
TTL/ST(2)
Interrupt-on-change pin or In-Circuit Debugger pin. Serial
programming data.
RC0/T1OSO/T1CKI
11
11
I/O
ST
RC0 can also be the Timer1 oscillator output or Timer1 clock
input.
RC1/T1OSI
12
12
I/O
ST
RC1 can also be the Timer1 oscillator input.
RC2/CCP1
13
13
I/O
ST
RC2 can also be the Capture1 input/Compare1 output/
PWM1 output.
RC3
14
14
I/O
ST
RC4
15
15
I/O
ST
RC5
16
16
I/O
ST
RC6/TX/CK
17
17
I/O
ST
RC6 can also be the USART Asynchronous Transmit or
Synchronous Clock.
RC7/RX/DT
18
18
I/O
ST
RC7 can also be the USART Asynchronous Receive or
Synchronous Data.
VSS
8, 19
8, 19
P
—
Ground reference for logic and I/O pins.
VDD
20
20
P
—
Positive supply for logic and I/O pins.
PORTC is a bi-directional I/O port.
Legend:
Note 1:
2:
3:
I = input
O = output
I/O = input/output
P = power
OD = Open Drain
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as the external interrupt or LVP mode.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
 2003 Microchip Technology Inc.
DS30569B-page 7
PIC16F870/871
TABLE 1-2:
PIC16F871 PINOUT DESCRIPTION
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
OSC1/CLKI
13
14
30
I
ST/CMOS(4)
OSC2/CLKO
14
15
31
O
—
Oscillator crystal output. Connects to crystal or resonator in
Crystal Oscillator mode. In RC mode, OSC2 pin outputs CLKO,
which has 1/4 the frequency of OSC1, and denotes the
instruction cycle rate.
MCLR/VPP/THV
1
2
18
I/P
ST
Master Clear (Reset) input or programming voltage input or
High Voltage Test mode control. This pin is an active low
RESET to the device.
RA0/AN0
2
3
19
I/O
TTL
RA0 can also be analog input 0.
RA1/AN1
3
4
20
I/O
TTL
RA1 can also be analog input 1.
RA2/AN2/VREF-
4
5
21
I/O
TTL
RA2 can also be analog input 2 or negative analog
reference voltage.
RA3/AN3/VREF+
5
6
22
I/O
TTL
RA3 can also be analog input 3 or positive analog
reference voltage.
RA4/T0CKI
6
7
23
I/O
ST
RA4 can also be the clock input to the Timer0
timer/counter. Output is open drain type.
RA5/AN4
7
8
24
I/O
TTL
Pin Name
Description
Oscillator crystal input/external clock source input.
PORTA is a bi-directional I/O port.
RA5 can also be analog input 4.
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-up on all inputs.
RB0/INT
33
36
8
I/O
TTL/ST(1)
RB1
34
37
9
I/O
TTL
RB2
35
38
10
I/O
TTL
RB3/PGM
36
39
11
I/O
TTL/ST(1)
RB4
37
41
14
I/O
TTL
TTL
RB0 can also be the external interrupt pin.
RB3 can also be the low voltage programming input.
Interrupt-on-change pin.
RB5
38
42
15
I/O
RB6/PGC
39
43
16
I/O
TTL/ST
(2)
Interrupt-on-change pin.
Interrupt-on-change pin or In-Circuit Debugger pin.
Serial programming clock.
RB7/PGD
40
44
17
I/O
TTL/ST(2)
Interrupt-on-change pin or In-Circuit Debugger pin.
Serial programming data.
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI
15
16
32
I/O
ST
RC0 can also be the Timer1 oscillator output or a Timer1
clock input.
RC1/T1OSI
16
18
35
I/O
ST
RC1 can also be the Timer1 oscillator input.
RC2/CCP1
17
19
36
I/O
ST
RC2 can also be the Capture1 input/Compare1 output/
PWM1 output.
RC3
18
20
37
I/O
ST
RC4
23
25
42
I/O
ST
RC5
24
26
43
I/O
ST
RC6/TX/CK
25
27
44
I/O
ST
RC6 can also be the USART Asynchronous Transmit or
Synchronous Clock.
RC7/RX/DT
26
29
1
I/O
ST
RC7 can also be the USART Asynchronous Receive or
Synchronous Data.
Legend:
Note 1:
2:
3:
4:
I = input
O = output
I/O = input/output
P = power
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as an external interrupt or LVP mode.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
DS30569B-page 8
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 1-2:
Pin Name
PIC16F871 PINOUT DESCRIPTION (CONTINUED)
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
Description
PORTD is a bi-directional I/O port or parallel slave port when
interfacing to a microprocessor bus.
RD0/PSP0
19
21
38
I/O
ST/TTL(3)
RD1/PSP1
20
22
39
I/O
ST/TTL(3)
RD2/PSP2
21
23
40
I/O
ST/TTL(3)
RD3/PSP3
22
24
41
I/O
ST/TTL(3)
RD4/PSP4
27
30
2
I/O
ST/TTL(3)
RD5/PSP5
28
31
3
I/O
ST/TTL(3)
RD6/PSP6
29
32
4
I/O
ST/TTL(3)
RD7/PSP7
30
33
5
I/O
ST/TTL(3)
RE0/RD/AN5
8
9
25
I/O
ST/TTL
(3)
RE0 can also be read control for the parallel slave port, or
analog input 5.
RE1/WR/AN6
9
10
26
I/O
ST/TTL(3)
RE1 can also be write control for the parallel slave port, or
analog input 6.
RE2/CS/AN7
10
11
27
I/O
ST/TTL(3)
RE2 can also be select control for the parallel slave port,
or analog input 7.
PORTE is a bi-directional I/O port.
VSS
12,31
13,34
6,29
P
—
Ground reference for logic and I/O pins.
VDD
11,32
12,35
7,28
P
—
Positive supply for logic and I/O pins.
NC
—
1,17,28,
40
12,13,
33,34
—
These pins are not internally connected. These pins should be
left unconnected.
Legend:
Note 1:
2:
3:
4:
I = input
O = output
I/O = input/output
P = power
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as an external interrupt or LVP mode.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
 2003 Microchip Technology Inc.
DS30569B-page 9
PIC16F870/871
NOTES:
DS30569B-page 10
 2003 Microchip Technology Inc.
PIC16F870/871
2.0
MEMORY ORGANIZATION
The PIC16F870/871 devices have three memory
blocks. The Program Memory and Data Memory have
separate buses, so that concurrent access can occur,
and is detailed in this section. The EEPROM data
memory block is detailed in Section 3.0.
2.2
The data memory is partitioned into multiple banks
which contain the General Purpose Registers and the
Special Function Registers. Bits RP1 (STATUS<6>)
and RP0 (STATUS<5>) are the bank select bits.
Additional information on device memory may be found
in the PICmicroTM Mid-Range MCU Family Reference
Manual (DS33023).
2.1
Program Memory Organization
The PIC16F870/871 devices have a 13-bit program
counter capable of addressing an 8K x 14 program
memory space. The PIC16F870/871 devices have
2K x 14 words of FLASH 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 2-1:
PIC16F870/871 PROGRAM
MEMORY MAP AND STACK
Bank
00
0
01
1
10
2
11
3
Note:
EEPROM Data Memory description can
be found in Section 3.0 of this Data Sheet.
GENERAL PURPOSE REGISTER
FILE
The register file can be accessed either directly, or
indirectly through the File Select Register FSR.
13
CALL, RETURN
RETFIE, RETLW
RP<1:0>
Each bank extends up to 7Fh (128 bytes). The lower
locations of each bank are reserved for the Special
Function Registers. Above the Special Function Registers are General Purpose Registers, implemented as
static RAM. All implemented banks contain Special
Function Registers. Some “high use” Special Function
Registers from one bank may be mirrored in another
bank for code reduction and quicker access.
2.2.1
PC<12:0>
Data Memory Organization
Stack Level 1
Stack Level 2
Stack Level 8
On-Chip
Program
Memory
RESET Vector
0000h
Interrupt Vector
0004h
0005h
Page 0
07FFh
0800h
1FFFh
 2003 Microchip Technology Inc.
DS30569B-page 11
PIC16F870/871
FIGURE 2-2:
PIC16F870/871 REGISTER FILE MAP
File
Address
Indirect addr.(*)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
PORTD(2)
PORTE(2)
PCLATH
INTCON
PIR1
PIR2
TMR1L
TMR1H
T1CON
TMR2
T2CON
CCPR1L
CCPR1H
CCP1CON
RCSTA
TXREG
RCREG
ADRESH
ADCON0
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
20h
General
Purpose
Register
File
Address
Indirect addr.(*)
80h
OPTION_REG 81h
PCL
82h
STATUS
83h
FSR
84h
TRISA
85h
TRISB
86h
TRISC
87h
88h
TRISD(2)
(2)
TRISE
89h
PCLATH
8Ah
INTCON
8Bh
PIE1
8Ch
PIE2
8Dh
PCON
8Eh
8Fh
90h
91h
PR2
92h
93h
94h
95h
96h
97h
TXSTA
98h
SPBRG
99h
9Ah
9Bh
9Ch
9Dh
ADRESL
9Eh
9Fh
ADCON1
General
Purpose
Register
A0h
32 Bytes
BFh
C0h
96 Bytes
7Fh
Bank 0
accesses
70h-7Fh
Bank 1
Indirect addr.(*) 100h
101h
TMR0
102h
PCL
103h
STATUS
104h
FSR
105h
106h
PORTB
107h
108h
109h
10Ah
PCLATH
10Bh
INTCON
10Ch
EEDATA
EEADR
10Dh
10Eh
EEDATH
10Fh
EEADRH
110h
Indirect addr.(*)
OPTION_REG
PCL
STATUS
FSR
TRISB
PCLATH
INTCON
EECON1
EECON2
Reserved(1)
Reserved(1)
180h
181h
182h
183h
184h
185h
186h
187h
188h
189h
18Ah
18Bh
18Ch
18Dh
18Eh
18Fh
190h
1A0h
120h
accesses
A0h - BFh
accesses
20h-7Fh
EFh
F0h
File
Address
File
Address
1BFh
1C0h
accesses
70h-7Fh
FFh
Bank 2
16Fh
170h
17Fh
accesses
70h-7Fh
1EFh
1F0h
1FFh
Bank 3
Unimplemented data memory locations, read as '0'.
* Not a physical register.
Note 1: These registers are reserved; maintain these registers clear.
2: These registers are not implemented on the PIC16F870.
DS30569B-page 12
 2003 Microchip Technology Inc.
PIC16F870/871
2.2.2
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. A list of these registers is
given in Table 2-1.
TABLE 2-1:
Address
The Special Function Registers can be classified into
two sets: core (CPU) and peripheral. Those registers
associated with the core functions are described in
detail in this section. Those related to the operation of
the peripheral features are described in detail in the
peripheral feature section.
SPECIAL FUNCTION REGISTER SUMMARY
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(2)
Bank 0
00h(4)
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(4)
PCL
Program Counter's (PC) Least Significant Byte
03h(4)
STATUS
04h(4)
FSR
05h
PORTA
06h
PORTB
PORTB Data Latch when written: PORTB pins when read
07h
PORTC
PORTC Data Latch when written: PORTC pins when read
xxxx xxxx uuuu uuuu
08h(5)
PORTD
PORTD Data Latch when written: PORTD pins when read
xxxx xxxx uuuu uuuu
09h(5)
PORTE
—
—
—
0Ah(1,4)
PCLATH
—
—
—
0Bh(4)
INTCON
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0Ch
PIR1
PSPIF(3)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
0000 -000 0000 -000
0Dh
PIR2
—
—
—
EEIF
—
—
—
—
---0 ---- ---0 ----
IRP
RP1
RP0
TO
0000 0000 0000 0000
PD
Z
DC
C
Indirect Data Memory Address Pointer
—
—
xxxx xxxx uuuu uuuu
PORTA Data Latch when written: PORTA pins when read
—
—
RE2
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
10h
T1CON
11h
TMR2
12h
T2CON
T1CKPS1
RE1
RE0
Write Buffer for the upper 5 bits of the Program Counter
0Fh
—
--0x 0000 --0u 0000
xxxx xxxx uuuu uuuu
0Eh
—
---- -xxx ---- -uuu
---0 0000 ---0 0000
0000 000x 0000 000u
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON --00 0000 --uu uuuu
TOUTPS3 TOUTPS2 TOUTPS1
TOUTPS0
TMR2ON
T2CKPS1 T2CKPS0 -000 0000 -000 0000
Timer2 Module’s Register
—
0001 1xxx 000q quuu
0000 0000 0000 0000
13h
—
Unimplemented
—
—
14h
—
Unimplemented
—
—
15h
CCPR1L
Capture/Compare/PWM Register1 (LSB)
16h
CCPR1H
Capture/Compare/PWM Register1 (MSB)
17h
CCP1CON
18h
RCSTA
19h
TXREG
USART Transmit Data Register
0000 0000 0000 0000
1Ah
RCREG
USART Receive Data Register
0000 0000 0000 0000
1Bh
—
Unimplemented
—
—
1Ch
—
Unimplemented
—
—
1Dh
—
Unimplemented
—
—
1Eh
ADRESH
1Fh
ADCON0
Legend:
Note 1:
2:
3:
4:
5:
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
—
—
CCP1X
CCP1Y
CCP1M3
CCP1M2
CCP1M1
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
CCP1M0 --00 0000 --00 0000
RX9D
A/D Result Register High Byte
ADCS1
ADCS0
CHS2
0000 000x 0000 000x
xxxx xxxx uuuu uuuu
CHS1
CHS0
GO/DONE
—
ADON
0000 00-0 0000 00-0
x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as '0', r = reserved.
Shaded locations are unimplemented, read as ‘0’.
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.
Other (non Power-up) Resets include external RESET through MCLR and Watchdog Timer Reset.
Bits PSPIE and PSPIF are reserved on the 28-pin devices; always maintain these bits clear.
These registers can be addressed from any bank.
PORTD, PORTE, TRISD and TRISE are not physically implemented on the 28-pin devices, read as ‘0’.
 2003 Microchip Technology Inc.
DS30569B-page 13
PIC16F870/871
TABLE 2-1:
Address
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
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(2)
Bank 1
80h(4)
INDF
81h
OPTION_REG
82h(4)
PCL
83h(4)
STATUS
84h(4)
FSR
85h
TRISA
86h
TRISB
PORTB Data Direction Register
87h
TRISC
PORTC Data Direction Register
1111 1111 1111 1111
88h(5)
TRISD
PORTD Data Direction Register
1111 1111 1111 1111
89h(5)
TRISE
IBF
OBF
IBOV
8Ah(1,4)
PCLATH
—
—
—
8Bh(4)
INTCON
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
8Ch
PIE1
PSPIE(3)
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
0000 -000 0000 -000
8Dh
PIE2
—
—
—
EEIE
—
—
—
—
---0 ---- ---0 ----
8Eh
PCON
—
—
—
—
—
—
POR
BOR
---- --qq ---- --uu
Addressing this location uses contents of FSR to address data memory (not a physical register)
RBPU
INTEDG
T0CS
T0SE
PS2
PS1
PS0
1111 1111 1111 1111
PD
Z
DC
C
0001 1xxx 000q quuu
Program Counter's (PC) Least Significant Byte
IRP
RP1
RP0
TO
0000 0000 0000 0000
Indirect Data Memory Address Pointer
—
—
0000 0000 0000 0000
PSA
xxxx xxxx uuuu uuuu
PORTA Data Direction Register
--11 1111 --11 1111
1111 1111 1111 1111
PSPMODE
—
PORTE Data Direction Bits
0000 -111 0000 -111
Write Buffer for the upper 5 bits of the Program Counter
---0 0000 ---0 0000
0000 000x 0000 000u
8Fh
—
Unimplemented
—
—
90h
—
Unimplemented
—
—
91h
—
Unimplemented
—
—
92h
PR2
Timer2 Period Register
1111 1111 1111 1111
93h
—
Unimplemented
—
—
94h
—
Unimplemented
—
—
95h
—
Unimplemented
—
—
96h
—
Unimplemented
—
—
97h
—
Unimplemented
—
—
98h
TXSTA
CSRC
TX9
TXEN
SYNC
—
BRGH
TRMT
TX9D
99h
SPBRG
9Ah
—
Unimplemented
—
—
9Bh
—
Unimplemented
—
—
9Ch
—
Unimplemented
—
—
9Dh
—
Unimplemented
—
—
9Eh
ADRESL
9Fh
ADCON1
Legend:
Note 1:
2:
3:
4:
5:
Baud Rate Generator Register
0000 -010 0000 -010
0000 0000 0000 0000
A/D Result Register Low Byte
ADFM
—
—
xxxx xxxx uuuu uuuu
—
PCFG3
PCFG2
PCFG1
PCFG0
0--- 0000
0--- 0000
x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as '0', r = reserved.
Shaded locations are unimplemented, read as ‘0’.
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.
Other (non Power-up) Resets include external RESET through MCLR and Watchdog Timer Reset.
Bits PSPIE and PSPIF are reserved on the 28-pin devices; always maintain these bits clear.
These registers can be addressed from any bank.
PORTD, PORTE, TRISD and TRISE are not physically implemented on the 28-pin devices, read as ‘0’.
DS30569B-page 14
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 2-1:
Address
SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
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(2)
Bank 2
100h(4)
INDF
Addressing this location uses contents of FSR to address data memory (not a physical register)
0000 0000 0000 0000
101h
TMR0
Timer0 Module’s Register
xxxx xxxx uuuu uuuu
102h(4)
PCL
Program Counter's (PC) Least Significant Byte
103h(4)
STATUS
104h(4)
FSR
IRP
RP1
RP0
0000 0000 0000 0000
TO
PD
Z
DC
C
Indirect Data Memory Address Pointer
0001 1xxx 000q quuu
xxxx xxxx uuuu uuuu
105h
—
Unimplemented
106h
PORTB
—
107h
—
Unimplemented
—
—
108h
—
Unimplemented
—
—
109h
—
Unimplemented
—
—
PORTB Data Latch when written: PORTB pins when read
—
xxxx xxxx uuuu uuuu
10Ah(1,4)
PCLATH
10Bh(4)
INTCON
10Ch
EEDATA
EEPROM Data Register
xxxx xxxx uuuu uuuu
10Dh
EEADR
EEPROM Address Register
xxxx xxxx uuuu uuuu
10Eh
EEDATH
—
—
10Fh
EEADRH
—
—
—
—
—
GIE
PEIE
T0IE
Write Buffer for the upper 5 bits of the Program Counter
INTE
RBIE
T0IF
INTF
RBIF
EEPROM Data Register High Byte
—
---0 0000 ---0 0000
0000 000x 0000 000u
xxxx xxxx uuuu uuuu
EEPROM Address Register High Byte
xxxx xxxx uuuu uuuu
Bank 3
180h(4)
INDF
181h
OPTION_REG
182h(4)
PCL
183h(4)
STATUS
184h(4)
FSR
185h
Addressing this location uses contents of FSR to address data memory (not a physical register)
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
PD
Z
DC
C
Program Counter's (PC) Least Significant Byte
IRP
RP1
RP0
TRISB
0000 0000 0000 0000
1111 1111 1111 1111
0000 0000 0000 0000
TO
Indirect Data Memory Address Pointer
—
186h
RBPU
0001 1xxx 000q quuu
xxxx xxxx uuuu uuuu
Unimplemented
—
PORTB Data Direction Register
—
1111 1111 1111 1111
187h
—
Unimplemented
—
—
188h
—
Unimplemented
—
—
189h
—
Unimplemented
—
—
18Ah(1,4)
PCLATH
18Bh(4)
18Ch
18Dh
EECON2
18Eh
18Fh
Legend:
Note 1:
2:
3:
4:
5:
—
—
—
Write Buffer for the upper 5 bits of the Program Counter
INTCON
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
EECON1
EEPGD
—
—
—
WRERR
WREN
WR
RD
x--- x000 x--- u000
---0 0000 ---0 0000
EEPROM Control Register2 (not a physical register)
---- ---- ---- ----
—
Reserved maintain clear
0000 0000 0000 0000
—
Reserved maintain clear
0000 0000 0000 0000
x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as '0', r = reserved.
Shaded locations are unimplemented, read as ‘0’.
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.
Other (non Power-up) Resets include external RESET through MCLR and Watchdog Timer Reset.
Bits PSPIE and PSPIF are reserved on the 28-pin devices; always maintain these bits clear.
These registers can be addressed from any bank.
PORTD, PORTE, TRISD and TRISE are not physically implemented on the 28-pin devices, read as ‘0’.
 2003 Microchip Technology Inc.
DS30569B-page 15
PIC16F870/871
2.2.2.1
STATUS Register
The STATUS register 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 TO and PD bits are not
writable, therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.
REGISTER 2-1:
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as 000u u1uu (where u = unchanged).
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 STATUS register. For
other instructions not affecting any status bits, see the
“Instruction Set Summary”.
Note 1: The C and DC bits operate as a borrow
and digit borrow bit, respectively, in subtraction. See the SUBLW and SUBWF
instructions for examples.
STATUS REGISTER (ADDRESS: 03h, 83h, 103h, 183h)
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
bit 7
bit 0
bit 7-6
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)
11 = Bank 1 (80h - FFh)
10 = Bank 0 (00h - 7Fh)
Each bank is 128 bytes.
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.
Legend:
DS30569B-page 16
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
2.2.2.2
OPTION_REG Register
The OPTION_REG register is a readable and writable
register, which contains various control bits to configure
the TMR0 prescaler/WDT postscaler (single assignable register known also as the prescaler), the External
INT interrupt, TMR0 and the weak pull-ups on PORTB.
Note:
To achieve a 1:1 prescaler assignment for
the TMR0 register, assign the prescaler to
the Watchdog Timer.
REGISTER 2-2:
OPTION_REG 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
bit 7
bit 0
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 (CLKO)
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
Bit Value
000
001
010
011
100
101
110
111
TMR0 Rate
1:2
1:4
1:8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
WDT Rate
1:1
1:2
1:4
1:8
1 : 16
1 : 32
1 : 64
1 : 128
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 17
PIC16F870/871
2.2.2.3
INTCON Register
Note:
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 External
RB0/INT pin interrupts.
REGISTER 2-3:
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.
INTCON REGISTER (ADDRESS: 0Bh, 8Bh, 10Bh, 18Bh)
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
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
bit 7
bit 0
bit 7
GIE: Global Interrupt Enable bit
1 = Enables all unmasked interrupts
0 = Disables all interrupts
bit 6
PEIE: Peripheral Interrupt Enable bit
1 = Enables all unmasked peripheral interrupts
0 = Disables all peripheral interrupts
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
Legend:
DS30569B-page 18
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
2.2.2.4
PIE1 Register
The PIE1 register contains the individual enable bits for
the peripheral interrupts.
Note:
Bit PEIE (INTCON<6>) must be set to
enable any peripheral interrupt.
REGISTER 2-4:
PIE1 REGISTER (ADDRESS: 8Ch)
R/W-0
R/W-0
R/W-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
PSPIE(1)
ADIE
RCIE
TXIE

CCP1IE
TMR2IE
TMR1IE
bit 7
bit 0
bit 7
PSPIE(1): Parallel Slave Port Read/Write Interrupt Enable bit
1 = Enables the PSP read/write interrupt
0 = Disables the PSP read/write interrupt
bit 6
ADIE: A/D Converter Interrupt Enable bit
1 = Enables the A/D converter interrupt
0 = Disables the A/D converter interrupt
bit 5
RCIE: USART Receive Interrupt Enable bit
1 = Enables the USART receive interrupt
0 = Disables the USART receive interrupt
bit 4
TXIE: USART Transmit Interrupt Enable bit
1 = Enables the USART transmit interrupt
0 = Disables the USART transmit interrupt
bit 3
Unimplemented: Read as ‘0’
bit 2
CCP1IE: CCP1 Interrupt Enable bit
1 = Enables the CCP1 interrupt
0 = Disables the CCP1 interrupt
bit 1
TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1 = Enables the TMR2 to PR2 match interrupt
0 = Disables the TMR2 to PR2 match interrupt
bit 0
TMR1IE: TMR1 Overflow Interrupt Enable bit
1 = Enables the TMR1 overflow interrupt
0 = Disables the TMR1 overflow interrupt
Note 1: PSPIE is reserved on the PIC16F870; always maintain this bit clear.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 19
PIC16F870/871
2.2.2.5
PIR1 Register
The PIR1 register contains the individual flag bits for
the peripheral interrupts.
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 bits are clear prior to enabling an
interrupt.
REGISTER 2-5:
PIR1 REGISTER (ADDRESS: 0Ch)
R/W-0
R/W-0
R-0
R-0
U-0
R/W-0
R/W-0
R/W-0
PSPIF(1)
ADIF
RCIF
TXIF

CCP1IF
TMR2IF
TMR1IF
bit 7
bit 0
bit 7
PSPIF(1): Parallel Slave Port Read/Write Interrupt Flag bit
1 = A read or a write operation has taken place (must be cleared in software)
0 = No read or write has occurred
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
RCIF: USART Receive Interrupt Flag bit
1 = The USART receive buffer is full
0 = The USART receive buffer is empty
bit 4
TXIF: USART Transmit Interrupt Flag bit
1 = The USART transmit buffer is empty
0 = The USART transmit buffer is full
bit 3
Unimplemented: Read as ‘0’
bit 2
CCP1IF: CCP1 Interrupt Flag bit
Capture mode:
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare mode:
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM mode:
Unused in this mode.
bit 1
TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1 = TMR2 to PR2 match occurred (must be cleared in software)
0 = No TMR2 to PR2 match occurred
bit 0
TMR1IF: TMR1 Overflow Interrupt Flag bit
1 = TMR1 register overflowed (must be cleared in software)
0 = TMR1 register did not overflow
Note 1: PSPIF is reserved on the PIC16F870; always maintain this bit clear.
Legend:
DS30569B-page 20
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
2.2.2.6
PIE2 Register
The PIE2 register contains the individual enable bit for
the EEPROM write operation interrupt.
REGISTER 2-6:
PIE2 REGISTER (ADDRESS: 8Dh)
U-0
U-0
U-0
R/W-0
U-0
U-0
U-0
U-0
—
—
—
EEIE
—
—
—
—
bit 7
bit 0
bit 7-5
Unimplemented: Read as '0'
bit 4
EEIE: EEPROM Write Operation Interrupt Enable bit
1 = Enable EE write interrupt
0 = Disable EE write interrupt
bit 3-0
Unimplemented: Read as '0'
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 21
PIC16F870/871
2.2.2.7
PIR2 Register
The PIR2 register contains the flag bit for the EEPROM
write operation interrupt.
.
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.
REGISTER 2-7:
PIR2 REGISTER (ADDRESS: 0Dh)
U-0
U-0
U-0
R/W-0
U-0
U-0
U-0
U-0
—
—
—
EEIF
—
—
—
—
bit 7
bit 0
bit 7-5
Unimplemented: Read as '0'
bit 4
EEIF: EEPROM Write Operation Interrupt Flag bit
1 = The write operation completed (must be cleared in software)
0 = The write operation is not complete or has not been started
bit 3-0
Unimplemented: Read as '0'
Legend:
DS30569B-page 22
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
2.2.2.8
PCON Register
The Power Control (PCON) register contains flag bits
to allow differentiation between a Power-on Reset
(POR), a Brown-out Reset (BOR), a Watchdog Reset
(WDT) and an external MCLR Reset.
Note:
BOR is unknown on POR. It must 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
predictable if the brown-out circuit is disabled (by clearing the BOREN bit in the
configuration word).
REGISTER 2-8:
PCON REGISTER (ADDRESS: 8Eh)
U-0
U-0
U-0
U-0
U-0
U-0
R/W-0
R/W-1
—
—
—
—
—
—
POR
BOR
bit 7
bit 0
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)
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 23
PIC16F870/871
2.3
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 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 2-3 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
(PCLATH<4:0> → PCH). The lower example in the figure shows how the PC is loaded during a CALL or GOTO
instruction (PCLATH<4:3> → PCH).
FIGURE 2-3:
LOADING OF PC IN
DIFFERENT SITUATIONS
PCH
PCL
12
8
7
0
PC
8
PCLATH<4:0>
5
Instruction with
PCL as
Destination
ALU
PCLATH
PCH
12
11 10
PCL
8
0
7
PC
GOTO,CALL
2
PCLATH<4:3>
11
Opcode <10:0>
PCLATH
2.3.1
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 exercised if the table location crosses a PCL
memory boundary (each 256-byte block). Refer to the
application note, “Implementing a Table Read"
(AN556).
2.3.2
STACK
The PIC16FXXX family has an 8-level 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.
DS30569B-page 24
The stack operates as a circular buffer. 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).
Note 1: There are no status bits to indicate stack
overflow or stack underflow conditions.
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.
2.4
Program Memory Paging
The PIC16FXXX architecture is capable of addressing
a continuous 8K word block of program memory. The
CALL and GOTO instructions provide 11 bits of the
address, which allows branches within any 2K program
memory page. Therefore, the 8K words of program
memory are broken into four pages. Since the
PIC16F872 has only 2K words of program memory or
one page, additional code is not required to ensure that
the correct page is selected before a CALL or GOTO
instruction is executed. The PCLATH<4:3> bits should
always be maintained as zeros. If a return from a CALL
instruction (or interrupt) is executed, the entire 13-bit
PC is popped off the stack. Manipulation of the
PCLATH is not required for the return instructions.
2.5
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 2-4.
A simple program to clear RAM locations 20h-2Fh
using indirect addressing is shown in Example 2-1.
EXAMPLE 2-1:
movlw
movwf
NEXT
clrf
incf
btfss
goto
CONTINUE
:
INDIRECT ADDRESSING
0x20
FSR
INDF
FSR,F
FSR,4
NEXT
;initialize pointer
;to RAM
;clear INDF register
;inc pointer
;all done?
;no clear next
;yes continue
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 2-4:
DIRECT/INDIRECT ADDRESSING
Direct Addressing
Indirect Addressing
from opcode
RP1: RP0
6
Bank Select
Location Select
0
IRP
7
Bank Select
00
01
10
FSR Register
0
Location Select
11
00h
80h
100h
180h
7Fh
FFh
17Fh
1FFh
Data
Memory(1)
Bank 0
Note 1:
Bank 1
Bank 2
Bank 3
For register file map detail see Figure 2-2.
 2003 Microchip Technology Inc.
DS30569B-page 25
PIC16F870/871
NOTES:
DS30569B-page 26
 2003 Microchip Technology Inc.
PIC16F870/871
3.0
DATA EEPROM AND FLASH
PROGRAM MEMORY
The Data EEPROM and FLASH Program Memory are
readable and writable during normal operation over the
entire VDD range. A bulk erase operation may not be
issued from user code (which includes removing code
protection). The data memory is not directly mapped in
the register file space. Instead, it is indirectly addressed
through the Special Function Registers (SFR).
There are six SFRs used to read and write the program
and data EEPROM memory. These registers are:
•
•
•
•
•
•
EECON1
EECON2
EEDATA
EEDATH
EEADR
EEADRH
The EEPROM data memory allows byte read and write.
When interfacing to the data memory block, EEDATA
holds the 8-bit data for read/write and EEADR holds the
address of the EEPROM location being accessed. The
registers EEDATH and EEADRH are not used for data
EEPROM access. The PIC16F870/871 devices have
64 bytes of data EEPROM with an address range from
0h to 3Fh.
The value written to program memory does not need to
be a valid instruction. Therefore, up to 14-bit numbers
can be stored in memory for use as calibration parameters, serial numbers, packed 7-bit ASCII, etc. Executing a program memory location containing data that
forms an invalid instruction results in a NOP.
3.1
EEADR
The address registers can address up to a maximum of
256 bytes of data EEPROM or up to a maximum of
8K words of program FLASH. However, the
PIC16F870/871 have 64 bytes of data EEPROM and
2K words of program FLASH.
When selecting a program address value, the MSByte
of the address is written to the EEADRH register and
the LSByte is written to the EEADR register. When
selecting a data address value, only the LSByte of the
address is written to the EEADR register.
On the PIC16F870/871 devices, the upper two bits of
the EEADR must always be cleared to prevent inadvertent access to the wrong location in data EEPROM.
This also applies to the program memory. The upper
five MSbits of EEADRH must always be clear during
program FLASH access.
3.2
EECON1 and EECON2 Registers
The EEPROM data memory is rated for high erase/
write cycles. The write time is controlled by an on-chip
timer. The write time will vary with voltage and temperature, as well as from chip-to-chip. Please refer to the
specifications for exact limits.
The EECON1 register is the control register for configuring and initiating the access. The EECON2 register is
not a physically implemented register, but is used
exclusively in the memory write sequence to prevent
inadvertent writes.
The program memory allows word reads and writes.
Program memory access allows for checksum calculation and calibration table storage. A byte or word write
automatically erases the location and writes the new
data (erase before write). Writing to program memory
will cease operation until the write is complete. The program memory cannot be accessed during the write,
therefore code cannot execute. During the write operation, the oscillator continues to clock the peripherals,
and therefore, they continue to operate. Interrupt
events will be detected and essentially “queued” until
the write is completed. When the write completes, the
next instruction in the pipeline is executed and the
branch to the interrupt vector address will occur.
There are many bits used to control the read and write
operations to EEPROM data and FLASH program
memory. The EEPGD bit determines if the access will
be a program or data memory access. When clear, any
subsequent operations will work on the EEPROM data
memory. When set, all subsequent operations will
operate in the program memory.
When interfacing to the program memory block, the
EEDATH:EEDATA registers form a two-byte word,
which holds the 14-bit data for read/write. The
EEADRH:EEADR registers form a two-byte word,
which holds the 13-bit address of the FLASH location
being accessed. The PIC16F870/871 devices have
2K words of program FLASH with an address range
from 0h to 7FFh. The unused upper bits in both the
EEDATH and EEDATA registers all read as ‘0’s.
 2003 Microchip Technology Inc.
Read operations only use one additional bit, RD, which
initiates the read operation from the desired memory
location. Once this bit is set, the value of the desired
memory location will be available in the data registers.
This bit cannot be cleared by firmware. It is automatically cleared at the end of the read operation. For
EEPROM data memory reads, the data will be available in the EEDATA register in the very next instruction
cycle after the RD bit is set. For program memory
reads, the data will be loaded into the
EEDATH:EEDATA registers, following the second
instruction after the RD bit is set.
DS30569B-page 27
PIC16F870/871
Write operations have two control bits, WR and WREN,
and two status bits, WRERR and EEIF. The WREN bit
is used to enable or disable the write operation. When
WREN is clear, the write operation will be disabled.
Therefore, the WREN bit must be set before executing
a write operation. The WR bit is used to initiate the write
operation. It also is automatically cleared at the end of
the write operation. The interrupt flag EEIF is used to
determine when the memory write completes. This flag
must be cleared in software before setting the WR bit.
For EEPROM data memory, once the WREN bit and
the WR bit have been set, the desired memory address
in EEADR will be erased, followed by a write of the data
in EEDATA. This operation takes place in parallel with
the microcontroller continuing to execute normally.
When the write is complete, the EEIF flag bit will be set.
For program memory, once the WREN bit and the WR
bit have been set, the microcontroller will cease to exe-
REGISTER 3-1:
cute instructions. The desired memory location pointed
to by EEADRH:EEADR will be erased. Then, the data
value in EEDATH:EEDATA will be programmed. When
complete, the EEIF flag bit will be set and the
microcontroller will continue to execute code.
The WRERR bit is used to indicate when the
PIC16F870/871 devices have been reset during a write
operation. WRERR should be cleared after Power-on
Reset. Thereafter, it should be checked on any other
RESET. The WRERR bit is set when a write operation
is interrupted by a MCLR Reset, or a WDT Time-out
Reset, during normal operation. In these situations, following a RESET, the user should check the WRERR bit
and rewrite the memory location, if set. The contents of
the data registers, address registers and EEPGD bit
are not affected by either MCLR Reset, or WDT
Time-out Reset, during normal operation.
EECON1 REGISTER (ADDRESS: 18Ch)
R/W-x
U-0
U-0
U-0
R/W-x
R/W-0
R/S-0
R/S-0
EEPGD
—
—
—
WRERR
WREN
WR
RD
bit 7
bit 0
bit 7
EEPGD: Program/Data EEPROM Select bit
1 = Accesses program memory
0 = Accesses data memory
(This bit cannot be changed while a read or write operation is in progress.)
bit 6-4
Unimplemented: Read as '0'
bit 3
WRERR: EEPROM Error Flag bit
1 = A write operation is prematurely terminated (any MCLR Reset or any WDT Reset during
normal operation)
0 = The write operation completed
bit 2
WREN: EEPROM Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the EEPROM
bit 1
WR: Write Control bit
1 = Initiates a write cycle. (The bit is cleared by hardware once write is complete. The WR bit
can only be set (not cleared) in software.)
0 = Write cycle to the EEPROM is complete
bit 0
RD: Read Control bit
1 = Initiates an EEPROM read. (RD is cleared in hardware. The RD bit can only be set (not
cleared) in software.)
0 = Does not initiate an EEPROM read
Legend:
DS30569B-page 28
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
3.3
Reading the EEPROM Data
Memory
Reading EEPROM data memory only requires that the
desired address to access be written to the EEADR
register and clear the EEPGD bit. After the RD bit is set,
data will be available in the EEDATA register on the
very next instruction cycle. EEDATA will hold this value
until another read operation is initiated or until it is
written by firmware.
The steps to reading the EEPROM data memory are:
1.
2.
3.
4.
Write the address to EEDATA. Make sure that
the address is not larger than the memory size
of the PIC16F870/871 devices.
Clear the EEPGD bit to point to EEPROM data
memory.
Set the RD bit to start the read operation.
Read the data from the EEDATA register.
EXAMPLE 3-1:
EEPROM DATA READ
BSF
BCF
MOVF
MOVWF
BSF
BCF
BSF
BCF
STATUS,
STATUS,
ADDR, W
EEADR
STATUS,
EECON1,
EECON1,
STATUS,
RP1
RP0
MOVF
EEDATA, W
RP0
EEPGD
RD
RP0
;
;Bank 2
;Write address
;to read from
;Bank 3
;Point to Data memory
;Start read operation
;Bank 2
The steps to write to EEPROM data memory are:
1.
If step 10 is not implemented, check the WR bit
to see if a write is in progress.
2. Write the address to EEADR. Make sure that the
address is not larger than the memory size of
the PIC16F870/871 devices.
3. Write the 8-bit data value to be programmed in
the EEDATA register.
4. Clear the EEPGD bit to point to EEPROM data
memory.
5. Set the WREN bit to enable program operations.
6. Disable interrupts (if enabled).
7. Execute the special five instruction sequence:
• Write 55h to EECON2 in two steps (first to W,
then to EECON2)
• Write AAh to EECON2 in two steps (first to
W, then to EECON2)
• Set the WR bit
8. Enable interrupts (if using interrupts).
9. Clear the WREN bit to disable program
operations.
10. At the completion of the write cycle, the WR bit
is cleared and the EEIF interrupt flag bit is set.
(EEIF must be cleared by firmware.) If step 1 is
not implemented, then firmware should check
for EEIF to be set, or WR to clear, to indicate the
end of the program cycle.
;W = EEDATA
EXAMPLE 3-2:
3.4
Writing to the EEPROM Data
Memory
There are many steps in writing to the EEPROM data
memory. Both address and data values must be written
to the SFRs. The EEPGD bit must be cleared, and the
WREN bit must be set, to enable writes. The WREN bit
should be kept clear at all times, except when writing to
the EEPROM data. The WR bit can only be set if the
WREN bit was set in a previous operation (i.e., they
both cannot be set in the same operation). The WREN
bit should then be cleared by firmware after the write.
Clearing the WREN bit before the write actually
completes will not terminate the write in progress.
Writes to EEPROM data memory must also be prefaced with a special sequence of instructions that prevent inadvertent write operations. This is a sequence of
five instructions that must be executed without interruptions. The firmware should verify that a write is not in
progress before starting another cycle.
 2003 Microchip Technology Inc.
EEPROM DATA WRITE
BSF STATUS, RP1 ;
BSF STATUS, RP0 ;Bank 3
BTFSC EECON1, WR
;Wait for
GOTO $-1
;write to finish
BCF STATUS, RP0 ;Bank 2
MOVF ADDR, W
;Address to
MOVWF EEADR
;write to
MOVF VALUE, W
;Data to
MOVWF EEDATA
;write
BSF STATUS, RP0 ;Bank 3
BCF EECON1, EEPGD ;Point to Data memory
BSF EECON1, WREN ;Enable writes
;Only disable interrupts
BCF INTCON, GIE ;if already enabled,
;otherwise discard
MOVLW 0x55
;Write 55h to
MOVWF EECON2
;EECON2
MOVLW 0xAA
;Write AAh to
MOVWF EECON2
;EECON2
BSF EECON1, WR
;Start write operation
;Only enable interrupts
BSF INTCON, GIE ;if using interrupts,
;otherwise discard
BCF EECON1, WREN ;Disable writes
DS30569B-page 29
PIC16F870/871
3.5
Reading the FLASH Program
Memory
3.6
Writing to the FLASH Program
Memory
Reading FLASH program memory is much like that of
EEPROM data memory, only two NOP instructions must
be inserted after the RD bit is set. These two instruction
cycles that the NOP instructions execute, will be used by
the microcontroller to read the data out of program
memory and insert the value into the EEDATH:EEDATA
registers. Data will be available following the second
NOP instruction. EEDATH and EEDATA will hold their
value until another read operation is initiated, or until
they are written by firmware.
Writing to FLASH program memory is unique, in that
the microcontroller does not execute instructions while
programming is taking place. The oscillator continues
to run and all peripherals continue to operate and
queue interrupts, if enabled. Once the write operation
completes (specification D133), the processor begins
executing code from where it left off. The other important difference when writing to FLASH program memory is that the WRT configuration bit, when clear,
prevents any writes to program memory (see Table 3-1).
The steps to reading the FLASH program memory are:
Just like EEPROM data memory, there are many steps
in writing to the FLASH program memory. Both address
and data values must be written to the SFRs. The
EEPGD bit must be set, and the WREN bit must be set
to enable writes. The WREN bit should be kept clear at
all times, except when writing to the FLASH program
memory. The WR bit can only be set if the WREN bit
was set in a previous operation (i.e., they both cannot
be set in the same operation). The WREN bit should
then be cleared by firmware after the write. Clearing the
WREN bit before the write actually completes will not
terminate the write in progress.
1.
2.
3.
4.
5.
Write the address to EEADRH:EEADR. Make
sure that the address is not larger than the
memory size of the PIC16F870/871 devices.
Set the EEPGD bit to point to FLASH program
memory.
Set the RD bit to start the read operation.
Execute two NOP instructions to allow the
microcontroller to read out of program memory.
Read the data from the EEDATH:EEDATA
registers.
EXAMPLE 3-3:
BSF
BCF
MOVF
MOVWF
MOVF
MOVWF
BSF
BSF
BSF
NOP
NOP
BCF
MOVF
MOVWF
MOVF
MOVWF
FLASH PROGRAM READ
STATUS, RP1
STATUS, RP0
ADDRL, W
EEADR
ADDRH,W
EEADRH
STATUS, RP0
EECON1, EEPGD
EECON1, RD
STATUS, RP0
EEDATA, W
DATAL
EEDATH,W
DATAH
;
;Bank 2
;Write the
;address bytes
;for the desired
;address to read
;Bank 3
;Point to Program memory
;Start read operation
;Required two NOPs
;
;Bank 2
;DATAL = EEDATA
;
;DATAH = EEDATH
;
Writes to program memory must also be prefaced with
a special sequence of instructions that prevent inadvertent write operations. This is a sequence of five
instructions that must be executed without interruption
for each byte written. These instructions must then be
followed by two NOP instructions to allow the microcontroller to setup for the write operation. Once the write is
complete, the execution of instructions starts with the
instruction after the second NOP.
The steps to write to program memory are:
1.
2.
3.
4.
5.
6.
7.
8.
9.
DS30569B-page 30
Write the address to EEADRH:EEADR. Make
sure that the address is not larger than the
memory size of the PIC16F870/871 devices.
Write the 14-bit data value to be programmed in
the EEDATH:EEDATA registers.
Set the EEPGD bit to point to FLASH program
memory.
Set the WREN bit to enable program operations.
Disable interrupts (if enabled).
Execute the special five instruction sequence:
• Write 55h to EECON2 in two steps (first to W,
then to EECON2)
• Write AAh to EECON2 in two steps (first to W,
then to EECON2)
• Set the WR bit
Execute two NOP instructions to allow the
microcontroller to setup for write operation.
Enable interrupts (if using interrupts).
Clear the WREN bit to disable program
operations.
 2003 Microchip Technology Inc.
PIC16F870/871
At the completion of the write cycle, the WR bit is
cleared and the EEIF interrupt flag bit is set. (EEIF
must be cleared by firmware.) Since the microcontroller
does not execute instructions during the write cycle, the
firmware does not necessarily have to check either
EEIF, or WR, to determine if the write had finished.
EXAMPLE 3-4:
FLASH PROGRAM WRITE
BSF
BCF
MOVF
MOVWF
MOVF
MOVWF
MOVF
MOVWF
MOVF
MOVWF
BSF
BSF
BSF
STATUS, RP1
STATUS, RP0
ADDRL, W
EEADR
ADDRH, W
EEADRH
VALUEL, W
EEDATA
VALUEH, W
EEDATH
STATUS, RP0
EECON1, EEPGD
EECON1, WREN
BCF
INTCON, GIE
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP
0x55
EECON2
0xAA
EECON2
EECON1, WR
BSF
INTCON, GIE
BCF
EECON1, WREN
3.7
;
;Bank 2
;Write address
;of desired
;program memory
;location
;Write value to
;program at
;desired memory
;location
;Bank 3
;Point to Program memory
;Enable writes
;Only disable interrupts
;if already enabled,
;otherwise discard
;Write 55h to
;EECON2
;Write AAh to
;EECON2
;Start write operation
;Two NOPs to allow micro
;to setup for write
;Only enable interrupts
;if using interrupts,
;otherwise discard
;Disable writes
Write Verify
The PIC16F870/871 devices do not automatically verify the value written during a write operation. Depending on the application, good programming practice may
dictate that the value written to memory be verified
against the original value. This should be used in applications where excessive writes can stress bits near the
specified endurance limits.
 2003 Microchip Technology Inc.
3.8
Protection Against Spurious
Writes
There are conditions when the device may not want to
write to the EEPROM data memory or FLASH program
memory. To protect against these spurious write conditions, various mechanisms have been built into the
PIC16F870/871 devices. On power-up, the WREN bit
is cleared and the Power-up Timer (if enabled)
prevents writes.
The write initiate sequence and the WREN bit together,
help prevent any accidental writes during brown-out,
power glitches, or firmware malfunction.
3.9
Operation While Code Protected
The PIC16F870/871 devices have two code protect
mechanisms, one bit for EEPROM data memory and
two bits for FLASH program memory. Data can be read
and written to the EEPROM data memory, regardless
of the state of the code protection bit, CPD. When code
protection is enabled and CPD cleared, external
access via ICSP is disabled, regardless of the state of
the program memory code protect bits. This prevents
the contents of EEPROM data memory from being read
out of the device.
The state of the program memory code protect bits,
CP0 and CP1, do not affect the execution of instructions out of program memory. The PIC16F870/871
devices can always read the values in program memory, regardless of the state of the code protect bits.
However, the state of the code protect bits and the
WRT bit will have different effects on writing to program
memory. Table 4-1 shows the effect of the code protect
bits and the WRT bit on program memory.
Once code protection has been enabled for either
EEPROM data memory or FLASH program memory,
only a full erase of the entire device will disable code
protection.
DS30569B-page 31
PIC16F870/871
3.10
FLASH Program Memory Write
Protection
The configuration word contains a bit that write protects
the FLASH program memory, called WRT. This bit can
only be accessed when programming the
PIC16F870/871 devices via ICSP. Once write protection is enabled, only an erase of the entire device will
disable it. When enabled, write protection prevents any
writes to FLASH program memory. Write protection
does not affect program memory reads.
TABLE 3-1:
READ/WRITE STATE OF INTERNAL FLASH PROGRAM MEMORY
Configuration Bits
Internal
Read
Memory Location
Internal
Write
ICSP Read ICSP Write
CP1
CP0
WRT
0
0
x
All program memory
Yes
No
No
No
0
1
0
Unprotected areas
Yes
No
Yes
No
0
1
0
Protected areas
Yes
No
No
No
0
1
1
Unprotected areas
Yes
Yes
Yes
No
0
1
1
Protected areas
Yes
No
No
No
1
0
0
Unprotected areas
Yes
No
Yes
No
1
0
0
Protected areas
Yes
No
No
No
1
0
1
Unprotected areas
Yes
Yes
Yes
No
1
0
1
Protected areas
Yes
No
No
No
1
1
0
All program memory
Yes
No
Yes
Yes
1
1
1
All program memory
Yes
Yes
Yes
Yes
TABLE 3-2:
REGISTERS ASSOCIATED WITH DATA EEPROM/PROGRAM FLASH
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
0Bh, 8Bh,
INTCON
10Bh, 18Bh
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x
0000 000u
xxxx xxxx
uuuu uuuu
xxxx xxxx
uuuu uuuu
Address
10Dh
EEADR
10Fh
EEADRH
10Ch
EEDATA
10Eh
EEDATH
—
—
18Ch
EECON1
EEPGD
—
18Dh
EECON2 EEPROM Control Register2 (not a physical register)
Legend:
Note 1:
EEPROM Address Register, Low Byte
—
—
—
EEPROM Address, High Byte
EEPROM Data Register, Low Byte
EEPROM Data Register, High Byte
—
—
WRERR
WREN
WR
RD
xxxx xxxx
uuuu uuuu
xxxx xxxx
uuuu uuuu
x--- x000
x--- u000
—
—
x = unknown, u = unchanged, r = reserved, - = unimplemented, read as '0'.
Shaded cells are not used during FLASH/EEPROM access.
These bits are reserved; always maintain these bits clear.
DS30569B-page 32
 2003 Microchip Technology Inc.
PIC16F870/871
4.0
I/O PORTS
FIGURE 4-1:
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.
Additional information on I/O ports may be found in the
PICmicro™ Mid-Range MCU Family Reference
Manual (DS33023).
4.1
Data
Bus
D
Q
VDD
WR
Port
Q
CK
P
Data Latch
PORTA and the TRISA Register
PORTA is a 6-bit wide bi-directional port. The corresponding data direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
Hi-Impedance mode). Clearing a TRISA bit (= 0) will
make the corresponding PORTA pin an output (i.e., put
the contents of the output latch on the selected pin).
BLOCK DIAGRAM OF
RA3:RA0 AND RA5 PINS
D
WR
TRIS
N
Q
VSS
Analog
Input
Mode
Q
CK
TRIS Latch
Other PORTA pins are multiplexed with analog inputs
and analog VREF input. The operation of each pin is
selected by clearing/setting the control bits in the
ADCON1 register (A/D Control Register 1).
Note:
On a Power-on Reset, these pins are
configured as analog inputs and read as
'0'.
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 4-1:
BCF
BCF
CLRF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
STATUS, RP0
0x06
ADCON1
0xCF
TRISA
Q
;
;Bank0
;Initialize PORTA by
;clearing output
;data latches
;Select Bank 1
;Configure all pins
;as digital inputs
;Value used to
;initialize data
;direction
;Set RA<3:0> as
;inputs
;RA<5:4> as outputs
;TRISA<7:6> are
;always read as '0'.
 2003 Microchip Technology Inc.
D
EN
RD PORT
To A/D Converter
Note 1:
I/O pins have protection diodes to VDD and VSS.
FIGURE 4-2:
Data
Bus
WR
PORT
BLOCK DIAGRAM OF
RA4/T0CKI PIN
D
Q
CK
Q
N
Data Latch
WR
TRIS
INITIALIZING PORTA
STATUS, RP0
STATUS, RP1
PORTA
TTL
Input
Buffer
RD TRIS
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, the
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. The RA4/T0CKI
pin is a Schmitt Trigger input and an open drain output.
All other PORTA pins have TTL input levels and full
CMOS output drivers.
I/O pin(1)
D
Q
CK
Q
I/O pin(1)
VSS
Schmitt
Trigger
Input
Buffer
TRIS Latch
RD TRIS
Q
D
ENEN
RD PORT
TMR0 Clock Input
Note 1:
I/O pin has protection diodes to VSS only.
DS30569B-page 33
PIC16F870/871
TABLE 4-1:
PORTA FUNCTIONS
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/VREF
bit3
TTL
Input/output or analog input or VREF.
RA4/T0CKI
bit4
ST
Input/output or external clock input for Timer0. Output is open drain type.
RA5/AN4
bit5
TTL
Input/output or analog input.
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 4-2:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name
Bit 7
Bit 6
05h
PORTA
—
—
85h
TRISA
—
—
9Fh
ADCON1 ADFM
Legend:
—
Value on
all other
RESETS
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
RA5
RA4
RA3
RA2
RA1
RA0
--0x 0000 --0u 0000
PORTA Data Direction Register
—
—
--11 1111 --11 1111
PCFG3 PCFG2 PCFG1 PCFG0 --0- 0000 --0- 0000
x = unknown, u = unchanged, - = unimplemented locations read as '0'.
Shaded cells are not used by PORTA.
DS30569B-page 34
 2003 Microchip Technology Inc.
PIC16F870/871
4.2
PORTB and the TRISB Register
PORTB is an 8-bit wide, bi-directional port. The corresponding data direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB
pin an input (i.e., put the corresponding output driver in
a Hi-Impedance mode). Clearing a TRISB bit (= 0) will
make the corresponding PORTB pin an output (i.e., put
the contents of the output latch on the selected pin).
Three pins of PORTB are multiplexed with the Low
Voltage Programming function: RB3/PGM, RB6/PGC
and RB7/PGD. The alternate functions of these pins
are described in the Special Features Section.
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_REG<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 4-3:
BLOCK DIAGRAM OF
RB3:RB0 PINS
Data Bus
WR Port
Weak
P Pull-up
Data Latch
D
Q
b)
Any read or write of PORTB. This will end the
mismatch condition.
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.
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.
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).
RB0/INT is discussed in detail in Section 11.10.1.
FIGURE 4-4:
I/O
BLOCK DIAGRAM OF
RB7:RB4 PINS
pin(1)
CK
VDD
RBPU(2)
TRIS Latch
D
Q
WR TRIS
a)
RB0/INT is an external interrupt input pin and is
configured using the INTEDG bit (OPTION_REG<6>).
VDD
RBPU(2)
This interrupt can wake the device from SLEEP. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
TTL
Input
Buffer
CK
Weak
P Pull-up
Data Latch
Data Bus
D
Q
I/O pin(1)
WR Port
CK
TRIS Latch
RD TRIS
D
Q
WR TRIS
RD Port
TTL
Input
Buffer
CK
EN
RB0/INT
RB3/PGM
RD TRIS
Schmitt Trigger
Buffer
Note 1:
2:
Q
D
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
Four of PORTB’s pins, RB7:RB4, have an interrupt-onchange 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 interrupton-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>).
 2003 Microchip Technology Inc.
Latch
Q
RD Port
From other
RB7:RB4 pins
D
EN
RD Port
Set RBIF
ST
Buffer
Q
Q1
D
RD Port
EN
Q3
RB7:RB6 in Serial Programming Mode
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
DS30569B-page 35
PIC16F870/871
TABLE 4-3:
Name
PORTB FUNCTIONS
Bit#
Buffer
(1)
Function
RB0/INT
bit0
TTL/ST
RB1
bit1
TTL
RB2
bit2
TTL
RB3/PGM
bit3
TTL/ST(1)
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/PGC
bit6
TTL/ST(2)
Input/output pin (with interrupt-on-change) or In-Circuit Debugger pin.
Internal software programmable weak pull-up. Serial programming clock.
RB7/PGD
bit7
TTL/ST(2)
Input/output pin (with interrupt-on-change) or In-Circuit Debugger pin.
Internal software programmable weak pull-up. Serial programming data.
Legend:
Note 1:
2:
Input/output pin. Internal software programmable weak pull-up.
Input/output pin. Internal software programmable weak pull-up.
Input/output pin or programming pin in LVP mode. Internal software
programmable weak pull-up.
TTL = TTL input, ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as the external interrupt or LVP mode.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
TABLE 4-4:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Name
06h, 106h
PORTB
86h, 186h
TRISB
81h, 181h
OPTION_REG
Legend:
Input/output pin or external interrupt input. Internal software
programmable weak pull-up.
Value on
all other
RESETS
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0
xxxx xxxx uuuu uuuu
T0SE
PSA
PS2
PS1
PS0
PORTB Data Direction Register
RBPU
INTEDG
T0CS
1111 1111 1111 1111
1111 1111 1111 1111
x = unknown, u = unchanged. Shaded cells are not used by PORTB.
DS30569B-page 36
 2003 Microchip Technology Inc.
PIC16F870/871
4.3
FIGURE 4-5:
PORTC and the TRISC Register
PORTC is an 8-bit wide, bi-directional port. The corresponding data direction register is TRISC. Setting a
TRISC bit (= 1) will make the corresponding PORTC
pin an input (i.e., put the corresponding output driver in
a Hi-Impedance mode). Clearing a TRISC bit (= 0) will
make the corresponding PORTC pin an output (i.e., put
the contents of the output latch on the selected pin).
PORTC BLOCK DIAGRAM
(PERIPHERAL OUTPUT
OVERRIDE)
Port/Peripheral Select(2)
Peripheral Data Out
Data Bus
WR
PORT
PORTC is multiplexed with several peripheral functions
(Table 4-5). PORTC pins have Schmitt Trigger input
buffers.
VDD
0
D
Q
P
1
CK
Q
Data Latch
WR
TRIS
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an output, while other peripherals override the TRIS bit to
make a pin an input. Since the TRIS bit override is in
effect while the peripheral is enabled, read-modifywrite instructions (BSF, BCF, XORWF) with TRISC as
the destination should be avoided. The user should
refer to the corresponding peripheral section for the
correct TRIS bit settings.
D
CK
I/O
pin(1)
Q
Q
N
TRIS Latch
Vss
Schmitt
Trigger
RD TRIS
Peripheral
OE(3)
Q
D
EN
RD
PORT
Peripheral Input
Note 1: I/O pins have diode protection to VDD and VSS.
2: Port/Peripheral Select signal selects between
port data and peripheral output.
3: Peripheral OE (Output Enable) is only activated
if Peripheral Select is active.
TABLE 4-5:
PORTC FUNCTIONS
Name
Bit#
Buffer Type
Function
RC0/T1OSO/T1CKI
bit0
ST
Input/output port pin or Timer1 oscillator output/Timer1 clock input.
RC1/T1OSI
bit1
ST
Input/output port pin or Timer1 oscillator input.
RC2/CCP1
bit2
ST
Input/output port pin or Capture1 input/Compare1 output/
PWM1 output.
RC3
bit3
ST
Input/output port pin.
RC4
bit4
ST
Input/output port pin.
RC5
bit5
ST
Input/output port pin.
RC6/TX/CK
bit6
ST
Input/output port pin or USART Asynchronous Transmit or
Synchronous Clock.
RC7/RX/DT
bit7
ST
Input/output port pin or USART Asynchronous Receive or
Synchronous Data.
Legend:
ST = Schmitt Trigger input
TABLE 4-6:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
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
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx
uuuu uuuu
1111 1111
1111 1111
07h
PORTC
87h
TRISC
Legend:
x = unknown, u = unchanged
PORTC Data Direction Register
 2003 Microchip Technology Inc.
DS30569B-page 37
PIC16F870/871
4.4
FIGURE 4-6:
PORTD and TRISD Registers
PORTD BLOCK DIAGRAM
(IN I/O PORT MODE)
This section is not applicable to the PIC16F870.
Data
Bus
PORTD is an 8-bit port with Schmitt Trigger input buffers. Each pin is individually configurable as an input or
output.
WR
Port
PORTD can be configured as an 8-bit wide microprocessor port (parallel slave port) by setting control bit
PSPMODE (TRISE<4>). In this mode, the input buffers
are TTL.
D
Q
I/O pin(1)
CK
Data Latch
D
WR
TRIS
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRIS
Q
D
ENEN
RD Port
Note 1: I/O pins have protection diodes to VDD and VSS.
TABLE 4-7:
PORTD FUNCTIONS
Name
Bit#
Buffer Type
RD0/PSP0
bit0
ST/TTL(1)
Input/output port pin or parallel slave port bit0.
RD1/PSP1
bit1
ST/TTL
(1)
Input/output port pin or parallel slave port bit1.
RD2/PSP2
bit2
ST/TTL
(1)
Input/output port pin or parallel slave port bit2.
RD3/PSP3
bit3
ST/TTL(1)
Input/output port pin or parallel slave port bit3.
RD4/PSP4
bit4
ST/TTL(1)
Input/output port pin or parallel slave port bit4.
RD5/PSP5
bit5
ST/TTL(1)
Input/output port pin or parallel slave port bit5.
RD6/PSP6
bit6
ST/TTL(1)
Input/output port pin or parallel slave port bit6.
RD7/PSP7
bit7
ST/TTL(1)
Input/output port pin or parallel slave port bit7.
Legend:
Note 1:
ST = Schmitt Trigger input, TTL = TTL input
Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
TABLE 4-8:
Address
Function
SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Name
08h
PORTD
88h
TRISD
89h
TRISE
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
RD7
RD6
RD5
RD4
RD3
RD2
RD1
RD0
xxxx xxxx
uuuu uuuu
1111 1111
1111 1111
0000 -111
0000 -111
PORTD Data Direction Register
IBF
OBF
IBOV
PSPMODE
—
PORTE Data Direction Bits
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PORTD.
DS30569B-page 38
 2003 Microchip Technology Inc.
PIC16F870/871
4.5
PORTE and TRISE Register
This section is not applicable to the PIC16F870.
PORTE has three pins, RE0/RD/AN5, RE1/WR/AN6
and RE2/CS/AN7, which are individually configurable
as inputs or outputs. These pins have Schmitt Trigger
input buffers.
I/O PORTE becomes control inputs for the microprocessor port when bit PSPMODE (TRISE<4>) is set. In
this mode, the user must make sure that the
TRISE<2:0> bits are set (pins are configured as digital
inputs). Ensure ADCON1 is configured for digital I/O. In
this mode, the input buffers are TTL.
FIGURE 4-7:
Data
Bus
WR
PORT
On a Power-on Reset, these pins are
configured as analog inputs.
 2003 Microchip Technology Inc.
Q
I/O pin(1)
CK
D
WR
TRIS
Q
Schmitt
Trigger
input
buffer
CK
TRIS Latch
RD TRIS
PORTE pins are multiplexed with analog inputs. When
selected as an analog input, these pins will read as '0's.
Note:
D
Data Latch
Register 4-1 shows the TRISE register, which also
controls the parallel slave port operation.
TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. The user must
make sure to keep the pins configured as inputs when
using them as analog inputs.
PORTE BLOCK DIAGRAM
(IN I/O PORT MODE)
Q
D
EN
RD PORT
Note 1: I/O pins have protection diodes to VDD and VSS.
DS30569B-page 39
PIC16F870/871
REGISTER 4-1:
TRISE REGISTER (ADDRESS: 89h)
R-0
R-0
R/W-0
R/W-0
U-0
R/W-1
R/W-1
R/W-1
IBF
OBF
IBOV
PSPMODE
—
Bit2
Bit1
Bit0
bit 7
bit 0
bit 7
Parallel Slave Port Status/Control Bits
IBF: Input Buffer Full Status bit
1 = A word has been received and is waiting to be read by the CPU
0 = No word has been received
bit 6
OBF: Output Buffer Full Status bit
1 = The output buffer still holds a previously written word
0 = The output buffer has been read
bit 5
IBOV: Input Buffer Overflow Detect bit (in Microprocessor mode)
1 = A write occurred when a previously input word has not been read
(must be cleared in software)
0 = No overflow occurred
bit 4
PSPMODE: Parallel Slave Port Mode Select bit
1 = Parallel Slave Port mode
0 = General Purpose I/O mode
bit 3
Unimplemented: Read as '0'
PORTE Data Direction Bits
bit 2
Bit2: Direction Control bit for pin RE2/CS/AN7
1 = Input
0 = Output
bit 1
Bit1: Direction Control bit for pin RE1/WR/AN6
1 = Input
0 = Output
bit 0
Bit0: Direction Control bit for pin RE0/RD/AN5
1 = Input
0 = Output
Legend:
DS30569B-page 40
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 4-9:
Name
PORTE FUNCTIONS
Bit#
Buffer Type
Function
RE0/RD/AN5
bit0
ST/TTL(1)
Input/output port pin or read control input in Parallel Slave Port mode or
analog input:
RD
1 = Not a read operation
0 = Read operation. Reads PORTD register (if chip selected.)
RE1/WR/AN6
bit1
ST/TTL(1)
Input/output port pin or write control input in Parallel Slave Port mode
or analog input:
WR
1 = Not a write operation
0 = Write operation. Writes PORTD register (if chip selected).
RE2/CS/AN7
bit2
ST/TTL(1)
Input/output port pin or chip select control input in Parallel Slave Port
mode or analog input:
CS
1 = Device is not selected
0 = Device is selected
Legend:
Note 1:
ST = Schmitt Trigger input, TTL = TTL input
Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
TABLE 4-10:
Addr
Name
SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
09h
PORTE
—
—
—
—
—
89h
TRISE
IBF
OBF
IBOV
PSPMODE
—
9Fh
ADCON1
ADFM
—
—
—
PCFG3
Legend:
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
RESETS
RE2
RE1
RE0
---- -xxx
---- -uuu
0000 -111
0000 -111
--0- 0000
--0- 0000
PORTE Data Direction Bits
PCFG2
PCFG1
PCFG0
x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PORTE.
 2003 Microchip Technology Inc.
DS30569B-page 41
PIC16F870/871
4.6
Parallel Slave Port
FIGURE 4-8:
PORTD AND PORTE
BLOCK DIAGRAM
(PARALLEL SLAVE PORT)
The Parallel Slave Port is not implemented on the
PIC16F870.
PORTD operates as an 8-bit wide Parallel Slave Port or
microprocessor port when control bit PSPMODE
(TRISE<4>) is set. In Slave mode, it is asynchronously
readable and writable by the external world through RD
control input pin RE0/RD and WR control input pin
RE1/WR.
It can directly interface to an 8-bit microprocessor data
bus. The external microprocessor can read or write the
PORTD latch as an 8-bit latch. Setting bit PSPMODE
enables port pin RE0/RD to be the RD input, RE1/WR
to be the WR input and RE2/CS to be the CS (chip
select) input. For this functionality, the corresponding
data direction bits of the TRISE register (TRISE<2:0>)
must be configured as inputs (set). The A/D port configuration bits PCFG3:PCFG0 (ADCON1<3:0>) must be
set to configure pins RE2:RE0 as digital I/O.
There are actually two 8-bit latches. One for data output and one for data input. The user writes 8-bit data to
the PORTD data latch and reads data from the port pin
latch (note that they have the same address). In this
mode, the TRISD register is ignored, since the
microprocessor is controlling the direction of data flow.
A write to the PSP occurs when both the CS and WR
lines are first detected low. When either the CS or WR
lines become high (level triggered), the Input Buffer Full
(IBF) status flag bit (TRISE<7>) is set on the Q4 clock
cycle, following the next Q2 cycle, to signal the write is
complete (Figure 4-9). The interrupt flag bit, PSPIF
(PIR1<7>), is also set on the same Q4 clock cycle. IBF
can only be cleared by reading the PORTD input latch.
The Input Buffer Overflow (IBOV) status flag bit
(TRISE<5>) is set if a second write to the PSP is
attempted when the previous byte has not been read
out of the buffer.
Data Bus
D
WR
Port
Q
RDx
pin
CK
TTL
Q
RD
Port
D
ENEN
One bit of PORTD
Set Interrupt Flag
PSPIF (PIR1<7>)
Read
TTL
RD
Chip Select
TTL
CS
Write
TTL
WR
Note: I/O pin has protection diodes to VDD and VSS.
A read from the PSP occurs when both the CS and RD
lines are first detected low. The Output Buffer Full
(OBF) status flag bit (TRISE<6>) is cleared immediately (Figure 4-10), indicating that the PORTD latch is
waiting to be read by the external bus. When either the
CS or RD pin becomes high (level triggered), the interrupt flag bit PSPIF is set on the Q4 clock cycle, following the next Q2 cycle, indicating that the read is
complete. OBF remains low until data is written to
PORTD by the user firmware.
When not in PSP mode, the IBF and OBF bits are held
clear. However, if flag bit IBOV was previously set, it
must be cleared in firmware.
An interrupt is generated and latched into flag bit
PSPIF when a read or write operation is completed.
PSPIF must be cleared by the user in firmware and the
interrupt can be disabled by clearing the interrupt
enable bit PSPIE (PIE1<7>).
DS30569B-page 42
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 4-9:
PARALLEL SLAVE PORT WRITE WAVEFORMS
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q4
Q1
Q2
Q3
Q4
CS
WR
RD
PORTD<7:0>
IBF
OBF
PSPIF
FIGURE 4-10:
PARALLEL SLAVE PORT READ WAVEFORMS
Q1
Q2
Q3
Q4
Q1
Q2
Q3
CS
WR
RD
PORTD<7:0>
IBF
OBF
PSPIF
TABLE 4-11:
Address
REGISTERS ASSOCIATED WITH PARALLEL SLAVE PORT
Name
08h
PORTD
09h
PORTE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
Value on:
POR, BOR
xxxx xxxx
uuuu uuuu
RE1
RE0
---- -xxx
---- -uuu
Port Data Latch when written: Port pins when read
—
—
—
—
—
IBF
RE2
Value on
all other
RESETS
Bit 1
89h
TRISE
OBF
IBOV
PSPMODE
—
PORTE Data Direction bits
0000 -111
0000 -111
0Ch
PIR1
PSPIF ADIF
RCIF
TXIF
—
CCP1IF TMR2IF
TMR1IF
0000 0000
0000 0000
RCIE
TXIE
—
CCP1IE TMR2IE TMR1IE
0000 0000
0000 0000
—
—
PCFG3
PCFG2
--0- 0000
--0- 0000
8Ch
PIE1
PSPIE ADIE
9Fh
ADCON1
ADFM
Legend:
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Parallel Slave Port.
 2003 Microchip Technology Inc.
—
PCFG1
PCFG0
DS30569B-page 43
PIC16F870/871
NOTES:
DS30569B-page 44
 2003 Microchip Technology Inc.
PIC16F870/871
5.0
TIMER0 MODULE
Counter mode is selected by setting bit T0CS
(OPTION_REG<5>). In Counter mode, Timer0 will
increment either on every rising, or falling edge of pin
RA4/T0CKI. The incrementing edge is determined by
the Timer0 Source Edge Select bit, T0SE
(OPTION_REG<4>). Clearing bit T0SE selects the rising edge. Restrictions on the external clock input are
discussed in detail in Section 5.2.
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
The prescaler is mutually exclusively shared between
the Timer0 module and the Watchdog Timer. The prescaler is not readable or writable. Section 5.3 details the
operation of the prescaler.
Figure 5-1 is a block diagram of the Timer0 module and
the prescaler shared with the WDT.
5.1
Additional information on the Timer0 module is available in the PICmicro™ Mid-Range MCU Family
Reference Manual (DS33023).
The TMR0 interrupt is generated when the TMR0 register overflows from FFh to 00h. This overflow sets bit
T0IF (INTCON<2>). The interrupt can be masked by
clearing bit T0IE (INTCON<5>). Bit T0IF must be
cleared in software by the Timer0 module Interrupt Service Routine before re-enabling this interrupt. The
TMR0 interrupt cannot awaken the processor from
SLEEP, since the timer is shut-off during SLEEP.
Timer mode is selected by clearing bit T0CS
(OPTION_REG<5>). In Timer mode, the Timer0 module will increment every instruction cycle (without prescaler). If the TMR0 register is written, the increment is
inhibited for the following two instruction cycles. The
user can work around this by writing an adjusted value
to the TMR0 register.
FIGURE 5-1:
Timer0 Interrupt
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
Data Bus
CLKO (= FOSC/4)
0
RA4/T0CKI
pin
8
M
U
X
1
M
U
X
0
1
SYNC
2
Cycles
TMR0 Reg
T0SE
T0CS
Set Flag Bit T0IF
on Overflow
PSA
PRESCALER
0
Watchdog
Timer
1
M
U
X
8-bit Prescaler
8
8 - to - 1MUX
PS2:PS0
PSA
WDT Enable bit
1
0
MUX
PSA
WDT
Time-out
Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION_REG<5:0>).
 2003 Microchip Technology Inc.
DS30569B-page 45
PIC16F870/871
5.2
Using Timer0 with an External
Clock
5.3
When no prescaler is used, the external 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. Therefore, it is
necessary for T0CKI to be high for at least 2 TOSC (and
a small RC delay of 20 ns) and low for at least 2 TOSC
(and a small RC delay of 20 ns). Refer to the electrical
specification of the desired device.
There is only one prescaler available, which is mutually
exclusively shared between the Timer0 module and the
Watchdog Timer. A prescaler assignment for the
Timer0 module means that there is no prescaler for the
Watchdog Timer, and vice-versa. This prescaler is not
readable or writable (see Figure 5-1).
The PSA and PS2:PS0 bits (OPTION_REG<3:0>)
determine the prescaler assignment and prescale ratio.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF1, MOVWF1,
BSF1,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.
Note:
REGISTER 5-1:
Prescaler
Writing to TMR0 when the prescaler is
assigned to Timer0, will clear the
prescaler count, but will not change the
prescaler assignment.
OPTION_REG REGISTER
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
bit 7
bit 0
bit 7
RBPU
bit 6
INTEDG
bit 5
T0CS: TMR0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKO)
bit 4
T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on 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
Bit Value TMR0 Rate WDT Rate
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
Legend:
Note:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
To avoid an unintended device RESET, the instruction sequence shown in the PICmicro™ Mid-Range MCU
Family Reference Manual (DS33023) must be executed when changing the prescaler assignment from
Timer0 to the WDT. This sequence must be followed even if the WDT is disabled.
DS30569B-page 46
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 5-1:
Address
01h,101h
REGISTERS ASSOCIATED WITH TIMER0
Name
TMR0
Bit 7
Legend:
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Timer0 Module’s Register
0Bh,8Bh,
INTCON
10Bh,18Bh
81h,181h
Bit 6
GIE
PEIE
T0IE
Value on:
POR, BOR
Value on
all other
RESETS
xxxx xxxx uuuu uuuu
INTE RBIE
OPTION_REG RBPU INTEDG T0CS T0SE
PSA
T0IF
INTF
RBIF 0000 000x 0000 000u
PS2
PS1
PS0
1111 1111 1111 1111
x = unknown, u = unchanged, - = unimplemented locations read as '0'.
Shaded cells are not used by Timer0.
 2003 Microchip Technology Inc.
DS30569B-page 47
PIC16F870/871
NOTES:
DS30569B-page 48
 2003 Microchip Technology Inc.
PIC16F870/871
6.0
TIMER1 MODULE
The Timer1 module is a 16-bit timer/counter consisting
of two 8-bit registers (TMR1H and TMR1L), which are
readable and writable. The TMR1 register pair
(TMR1H:TMR1L) increments from 0000h to FFFFh
and rolls over to 0000h. The TMR1 interrupt, if enabled,
is generated on overflow, which is latched in interrupt
flag bit, TMR1IF (PIR1<0>). This interrupt can be
enabled/disabled by setting/clearing TMR1 interrupt
enable bit, TMR1IE (PIE1<0>).
Timer1 can operate in one of two modes:
• As a timer
• As a counter
The Operating mode is determined by the clock select
bit, TMR1CS (T1CON<1>).
REGISTER 6-1:
In Timer mode, Timer1 increments every instruction
cycle. In Counter mode, it increments on every rising
edge of the external clock input.
Timer1 can be enabled/disabled by setting/clearing
control bit, TMR1ON (T1CON<0>).
Timer1 also has an internal “RESET input”. This
RESET can be generated by either of the two CCP
modules (Section 8.0). Register 6-1 shows the Timer1
control register.
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T1CKI pins
become inputs. That is, the TRISC<1:0> value is
ignored, and these pins read as ‘0’.
Additional information on timer modules is available in
the PICmicro™ Mid-Range MCU Family Reference
Manual (DS33023).
T1CON: TIMER1 CONTROL REGISTER (ADDRESS: 10h)
U-0
U-0
—
—
R/W-0
R/W-0
T1CKPS1 T1CKPS0
R/W-0
T1OSCEN
R/W-0
R/W-0
bit 7
bit 0
bit 7-6
Unimplemented: Read as '0'
bit 5-4
T1CKPS1:T1CKPS0: Timer1 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 3
T1OSCEN: Timer1 Oscillator Enable Control bit
1 = Oscillator is enabled
0 = Oscillator is shut-off (the oscillator inverter is turned off to eliminate power drain)
bit 2
T1SYNC: Timer1 External Clock Input Synchronization Control bit
When TMR1CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR1CS = 0:
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
bit 1
TMR1CS: Timer1 Clock Source Select bit
1 = External clock from pin RC0/T1OSO/T1CKI (on the rising edge)
0 = Internal clock (FOSC/4)
bit 0
R/W-0
T1SYNC TMR1CS TMR1ON
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 49
PIC16F870/871
6.1
Timer1 Operation in Timer Mode
Timer mode is selected by clearing the TMR1CS
(T1CON<1>) bit. In this mode, the input clock to the
timer is FOSC/4. The synchronize control bit, T1SYNC
(T1CON<2>), has no effect, since the internal clock is
always in sync.
FIGURE 6-1:
6.2
Timer1 Counter Operation
Timer1 may operate in either a Synchronous, or an
Asynchronous mode, depending on the setting of the
TMR1CS bit.
When Timer1 is being incremented via an external
source, increments occur on a rising edge. After Timer1
is enabled in Counter mode, the module must first have
a falling edge before the counter begins to increment.
TIMER1 INCREMENTING EDGE
T1CKI
(Default High)
T1CKI
(Default Low)
Note: Arrows indicate counter increments.
6.3
Timer1 Operation in Synchronized
Counter Mode
Counter mode is selected by setting bit TMR1CS. In
this mode, the timer increments on every rising edge of
clock input on pin RC1/T1OSI, when bit T1OSCEN is
set, or on pin RC0/T1OSO/T1CKI, when bit T1OSCEN
is cleared.
FIGURE 6-2:
If T1SYNC is cleared, then the external clock input is
synchronized with internal phase clocks. The synchronization is done after the prescaler stage. The
prescaler stage is an asynchronous ripple counter.
In this configuration, during SLEEP mode, Timer1 will
not increment even if the external clock is present,
since the synchronization circuit is shut-off. The
prescaler, however, will continue to increment.
TIMER1 BLOCK DIAGRAM
Set Flag bit
TMR1IF on
Overflow
TMR1H
Synchronized
Clock Input
0
TMR1
TMR1L
1
TMR1ON
On/Off
T1SYNC
T1OSC
RC0/T1OSO/T1CKI
RC1/T1OSI
1
T1OSCEN FOSC/4
Enable
Internal
Oscillator(1) Clock
Synchronize
Prescaler
1, 2, 4, 8
det
0
2
T1CKPS1:T1CKPS0
Q Clock
TMR1CS
Note 1: When the T1OSCEN bit is cleared, the inverter is turned off. This eliminates power drain.
DS30569B-page 50
 2003 Microchip Technology Inc.
PIC16F870/871
6.4
Timer1 Operation in
Asynchronous Counter Mode
TABLE 6-1:
CAPACITOR SELECTION FOR
THE TIMER1 OSCILLATOR
If control bit T1SYNC (T1CON<2>) is set, the external
clock input is not synchronized. The timer continues to
increment asynchronous to the internal phase clocks.
The timer will continue to run during SLEEP and can
generate an interrupt-on-overflow, which will wake-up
the processor. However, special precautions in
software are needed to read/write the timer
(Section 6.4.1).
Osc Type
In Asynchronous Counter mode, Timer1 cannot be
used as a time base for capture or compare operations.
32.768 kHz
Epson C-001R32.768K-A
± 20 PPM
100 kHz
Epson C-2 100.00 KC-P
± 20 PPM
200 kHz
STD XTL 200.000 kHz
± 20 PPM
6.4.1
READING AND WRITING TIMER1 IN
ASYNCHRONOUS COUNTER
MODE
Reading TMR1H or TMR1L while the timer is running
from an external asynchronous clock, will ensure a
valid read (taken care of in hardware). However, the
user should keep in mind that reading the 16-bit timer
in two 8-bit values itself, poses certain problems, since
the timer may overflow between the reads.
For writes, it is recommended that the user simply stop
the timer and write the desired values. A write contention may occur by writing to the timer registers, while
the register is incrementing. This may produce an
unpredictable value in the timer register.
Reading the 16-bit value requires some care.
Examples 12-2 and 12-3 in the PICmicro™ Mid-Range
MCU Family Reference Manual (DS33023) show how
to read and write Timer1 when it is running in
Asynchronous mode.
6.5
Timer1 Oscillator
A crystal oscillator circuit is built-in between pins T1OSI
(input) and T1OSO (amplifier output). It is enabled by
setting control bit, T1OSCEN (T1CON<3>). The oscillator is a low power oscillator, rated up to 200 kHz. It will
continue to run during SLEEP. It is primarily intended
for use with a 32 kHz crystal. Table 6-1 shows the
capacitor selection for the Timer1 oscillator.
LP
Freq.
C1
C2
32 kHz
33 pF
33 pF
100 kHz
15 pF
15 pF
200 kHz
15 pF
15 pF
These values are for design guidance only.
Crystals Tested:
Note 1:
2:
6.6
Higher capacitance increases the stability
of oscillator, but also increases the start-up
time.
Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for
appropriate values of external components.
Resetting Timer1 Using a CCP
Trigger Output
If the CCP1 module is configured in Compare mode to
generate a “special event trigger” (CCP1M3:CCP1M0
= 1011), this signal will reset Timer1.
Note:
The special event triggers from the CCP1
module will not set interrupt flag bit
TMR1IF (PIR1<0>).
Timer1 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature.
If Timer1 is running in Asynchronous Counter mode,
this RESET operation may not work.
In the event that a write to Timer1 coincides with a
special event trigger from CCP1, the write will take
precedence.
In this mode of operation, the CCPRH:CCPRL register
pair effectively becomes the period register for Timer1.
The Timer1 oscillator is identical to the LP oscillator.
The user must provide a software time delay to ensure
proper oscillator start-up.
 2003 Microchip Technology Inc.
DS30569B-page 51
PIC16F870/871
6.7
Resetting of Timer1 Register Pair
(TMR1H, TMR1L)
6.8
Timer1 Prescaler
The prescaler counter is cleared on writes to the
TMR1H or TMR1L registers.
TMR1H and TMR1L registers are not reset to 00h on a
POR, or any other RESET, except by the CCP1 special
event trigger.
T1CON register is reset to 00h on a Power-on Reset,
or a Brown-out Reset, which shuts off the timer and
leaves a 1:1 prescale. In all other RESETS, the register
is unaffected.
TABLE 6-2:
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Value on
all other
RESETS
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
CCP1IE TMR2IE TMR1IE 0000 -000 0000 -000
0Eh
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
0Fh
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
10h
T1CON
Legend:
Note 1:
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer1 module.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
Address
Name
0Bh,8Bh,
INTCON
10Bh, 18Bh
0Ch
DS30569B-page 52
—
—
TMR1IF 0000 -000 0000 -000
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
 2003 Microchip Technology Inc.
PIC16F870/871
7.0
TIMER2 MODULE
Register 7-1 shows the Timer2 control register.
Timer2 is an 8-bit timer with a prescaler and a
postscaler. It can be used as the PWM time base for the
PWM mode of the CCP module(s). The TMR2 register
is readable and writable, and is cleared on any device
RESET.
Additional information on timer modules is available in
the PICmicro™ Mid-Range MCU Family Reference
Manual (DS33023).
FIGURE 7-1:
The input clock (FOSC/4) has a prescale option of 1:1,
1:4,
or
1:16,
selected
by
control
bits
T2CKPS1:T2CKPS0 (T2CON<1:0>).
Sets Flag
bit TMR2IF
TIMER2 BLOCK DIAGRAM
TMR2
Output(1)
RESET
The Timer2 module has an 8-bit period register, PR2.
Timer2 increments from 00h until it matches PR2 and
then resets to 00h on the next increment cycle. PR2 is
a readable and writable register. The PR2 register is
initialized to FFh upon RESET.
Postscaler
1:1 to 1:16
EQ
4
The match output of TMR2 goes through a 4-bit
postscaler (which gives a 1:1 to 1:16 scaling inclusive)
to generate a TMR2 interrupt (latched in flag bit
TMR2IF (PIR1<1>)).
TMR2 Reg
Prescaler
1:1, 1:4, 1:16
2
Comparator
PR2 Reg
FOSC/4
T2CKPS1:
T2CKPS0
T2OUTPS3:
T2OUTPS0
Note 1: TMR2 register output can be software selected by the
SSP module as a baud clock.
Timer2 can be shut-off by clearing control bit, TMR2ON
(T2CON<2>), to minimize power consumption.
REGISTER 7-1:
T2CON: TIMER2 CONTROL REGISTER (ADDRESS 12h)
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0
bit 7
bit 0
bit 7
Unimplemented: Read as '0'
bit 6-3
TOUTPS3:TOUTPS0: Timer2 Output Postscale Select bits
0000 = 1:1 Postscale
0001 = 1:2 Postscale
0010 = 1:3 Postscale
•
•
•
1111 = 1:16 Postscale
bit 2
TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
bit 1-0
T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
1x = Prescaler is 16
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 53
PIC16F870/871
7.1
Timer2 Prescaler and Postscaler
The prescaler and postscaler counters are cleared
when any of the following occurs:
• a write to the TMR2 register
• a write to the T2CON register
• any device RESET (POR, MCLR Reset, WDT
Reset, or BOR)
7.2
Output of TMR2
The output of TMR2 (before the postscaler) is fed to the
SSP module, which optionally uses it to generate shift
clock.
TMR2 is not cleared when T2CON is written.
TABLE 7-1:
Address
REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Name
0Bh,8Bh, INTCON
10Bh,18Bh
Value on
all other
RESETS
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
0Ch
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF 0000 -000 0000 -000
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE 0000 -000 0000 -000
11h
TMR2
Timer2 Module’s Register
12h
T2CON
92h
PR2
Legend:
Note 1:
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer2 module.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
DS30569B-page 54
—
0000 0000 0000 0000
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Timer2 Period Register
1111 1111 1111 1111
 2003 Microchip Technology Inc.
PIC16F870/871
8.0
CAPTURE/COMPARE/PWM
MODULES
Each Capture/Compare/PWM (CCP) module contains
a 16-bit register which can operate as a:
Additional information on CCP modules is available in
the PICmicro™ Mid-Range MCU Family Reference
Manual (DS33023) and in application note AN594,
“Using the CCP Modules” (DS00594).
TABLE 8-1:
• 16-bit Capture register
• 16-bit Compare register
• PWM Master/Slave Duty Cycle register
Table 8-1 shows the resources and interactions of the
CCP module. In the following sections, the operation of
a CCP module is described.
8.1
CCP MODE - TIMER
RESOURCES REQUIRED
CCP Mode
Timer Resource
Capture
Compare
PWM
Timer1
Timer1
Timer2
CCP1 Module
Capture/Compare/PWM Register1 (CCPR1) is comprised of two 8-bit registers: CCPR1L (low byte) and
CCPR1H (high byte). The CCP1CON register controls
the operation of CCP1. The special event trigger is
generated by a compare match and will reset Timer1
and start an A/D conversion (if the A/D module is
enabled).
REGISTER 8-1:
CCP1CON REGISTER REGISTER (ADDRESS: 17h/1Dh)
U-0
U-0
R/W-0
R/W-0
R/W-0
—
—
CCP1X
CCP1Y
CCP1M3
R/W-0
R/W-0
CCP1M2 CCP1M1
R/W-0
CCP1M0
bit 7
bit 0
bit 7-6
Unimplemented: Read as '0'
bit 5-4
CCP1X:CCP1Y: PWM Least Significant bits
Capture mode:
Unused
Compare mode:
Unused
PWM mode:
These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L.
bit 3-0
CCP1M3:CCP1M0: CCP1 Mode Select bits
0000 = Capture/Compare/PWM disabled (resets CCP1 module)
0100 = Capture mode, every falling edge
0101 = Capture mode, every rising edge
0110 = Capture mode, every 4th rising edge
0111 = Capture mode, every 16th rising edge
1000 = Compare mode, set output on match (CCP1IF bit is set)
1001 = Compare mode, clear output on match (CCP1IF bit is set)
1010 = Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin is
unaffected)
1011 = Compare mode, trigger special event (CCP1IF bit is set, CCP1 pin is unaffected);
CCP1resets TMR1, and starts an A/D conversion (if A/D module is enabled)
11xx = PWM mode
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 55
PIC16F870/871
8.2
8.2.2
Capture Mode
TIMER1 MODE SELECTION
In Capture mode, CCPR1H:CCPR1L captures the
16-bit value of the TMR1 register when an event occurs
on pin RC2/CCP1. An event is defined as one of the
following:
Timer1 must be running in Timer mode, or Synchronized Counter mode, for the CCP module to use the
capture feature. In Asynchronous Counter mode, the
capture operation may not work.
•
•
•
•
8.2.3
Every falling edge
Every rising edge
Every 4th rising edge
Every 16th rising edge
The type of event is configured by control bits
CCP1M3:CCP1M0 (CCP1CON<3:0>). When a capture is made, the interrupt request flag bit CCP1IF
(PIR1<2>) is set. The interrupt flag must be cleared in
software. If another capture occurs before the value in
register CCPR1 is read, the old captured value is
overwritten by the new value.
8.2.1
CCP PIN CONFIGURATION
In Capture mode, the RC2/CCP1 pin should be
configured as an input by setting the TRISC<2> bit.
Note:
If the RC2/CCP1 pin is configured as an
output, a write to the port can cause a
capture condition.
FIGURE 8-1:
RC2/CCP1
pin
CAPTURE MODE
OPERATION BLOCK
DIAGRAM
Prescaler
÷ 1, 4, 16
Set Flag bit CCP1IF
(PIR1<2>)
CCPR1H
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep bit
CCP1IE (PIE1<2>) clear to avoid false interrupts and
should clear the flag bit, CCP1IF, following any such
change in Operating mode.
8.2.4
Switching from one capture prescaler to another may
generate an interrupt. Also, the prescaler counter will
not be cleared, therefore, the first capture may be from
a non-zero prescaler. Example 8-1 shows the recommended method for switching between capture prescalers. This example also clears the prescaler counter
and will not generate the “false” interrupt.
EXAMPLE 8-1:
CLRF
MOVLW
CCPR1L
Capture
Enable
TMR1H
CCP PRESCALER
There are four prescaler settings, specified by bits
CCP1M3:CCP1M0. Whenever the CCP module is
turned off, or the CCP module is not in Capture mode,
the prescaler counter is cleared. Any RESET will clear
the prescaler counter.
MOVWF
and
Edge Detect
SOFTWARE INTERRUPT
CHANGING BETWEEN
CAPTURE PRESCALERS
CCP1CON
; Turn CCP module off
NEW_CAPT_PS ; Load the W reg with
; the new prescaler
; move value and CCP ON
CCP1CON
; Load CCP1CON with this
; value
TMR1L
CCP1CON<3:0>
Qs
DS30569B-page 56
 2003 Microchip Technology Inc.
PIC16F870/871
8.3
8.3.2
Compare Mode
In Compare mode, the 16-bit CCPR1 register value is
constantly compared against the TMR1 register pair
value. When a match occurs, the RC2/CCP1 pin is:
• Driven high
• Driven low
• Remains unchanged
FIGURE 8-2:
COMPARE MODE
OPERATION BLOCK
DIAGRAM
Special event trigger will:
reset Timer1, but not set interrupt flag bit TMR1IF (PIR1<0>),
and set bit GO/DONE (ADCON0<2>).
Special Event Trigger
RC2/CCP1
pin
CCPR1H CCPR1L
S
R
TRISC<2>
Output Enable
8.3.1
Output
Logic
Match
CCP1CON<3:0>
Mode Select
SOFTWARE INTERRUPT MODE
When Generate Software Interrupt mode is chosen, the
CCP1 pin is not affected. The CCPIF bit is set, causing
a CCP interrupt (if enabled).
8.3.4
SPECIAL EVENT TRIGGER
In this mode, an internal hardware trigger is generated,
which may be used to initiate an action.
The special event trigger output of CCP1 resets the
TMR1 register pair, and starts an A/D conversion (if A/D
module is enabled). This allows the CCPR1 register to
effectively be a 16-bit programmable period register for
Timer1.
Note:
Set Flag bit CCP1IF
(PIR1<2>)
Q
Timer1 must be running in Timer mode, or Synchronized Counter mode, if the CCP module is using the
compare feature. In Asynchronous Counter mode, the
compare operation may not work.
8.3.3
The action on the pin is based on the value of control
bits, CCP1M3:CCP1M0 (CCP1CON<3:0>). At the
same time, interrupt flag bit CCP1IF is set.
TIMER1 MODE SELECTION
The special event trigger from the CCP1
module will not set interrupt flag bit
TMR1IF (PIR1<0>).
Comparator
TMR1H
TMR1L
CCP PIN CONFIGURATION
The user must configure the RC2/CCP1 pin as an
output by clearing the TRISC<2> bit.
Note:
Clearing the CCP1CON register will force
the RC2/CCP1 compare output latch to
the default low level. This is not the
PORTC I/O data latch.
 2003 Microchip Technology Inc.
DS30569B-page 57
PIC16F870/871
8.4
8.4.1
PWM Mode (PWM)
In Pulse Width Modulation mode, the CCP1 pin produces up to a 10-bit resolution PWM output. Since the
CCP1 pin is multiplexed with the PORTC data latch, the
TRISC<2> bit must be cleared to make the CCP1 pin
an output.
Note:
Clearing the CCP1CON register will force
the CCP1 PWM output latch to the default
low level. This is not the PORTC I/O data
latch.
Figure 8-3 shows a simplified block diagram of the
CCP module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 8.4.3.
FIGURE 8-3:
SIMPLIFIED PWM BLOCK
DIAGRAM
Duty Cycle Registers
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
PWM period = [(PR2) + 1] • 4 • TOSC •
(TMR2 prescale value)
PWM frequency is defined as 1 / [PWM period].
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCP1 pin is set (exception: if PWM duty
cycle = 0%, the CCP1 pin will not be set)
• The PWM duty cycle is latched from CCPR1L into
CCPR1H
Note:
CCP1CON<5:4>
CCPR1L
8.4.2
CCPR1H (Slave)
RC2/CCP1
R
Comparator
TMR2
Q
(Note 1)
S
TRISC<2>
Comparator
Clear Timer,
CCP1 pin and
latch D.C.
PR2
Note 1:
The 8-bit timer is concatenated with 2-bit internal Q
clock, or 2 bits of the prescaler, to create 10-bit time
base.
A PWM output (Figure 8-4) has a time base (period)
and a time that the output stays high (duty cycle). The
frequency of the PWM is the inverse of the period
(1/period).
FIGURE 8-4:
PWM OUTPUT
Period
PWM PERIOD
The Timer2 postscaler (see Section 7.1) is
not used in the determination of the PWM
frequency. The postscaler could be used
to have a servo update rate at a different
frequency than the PWM output.
PWM DUTY CYCLE
The PWM duty cycle is specified by writing to the
CCPR1L register and to the CCP1CON<5:4> bits. Up
to 10-bit resolution is available. The CCPR1L contains
the eight MSbs and the CCP1CON<5:4> contains the
two LSbs. This 10-bit value is represented by
CCPR1L:CCP1CON<5:4>. The following equation is
used to calculate the PWM duty cycle in time:
PWM duty cycle = (CCPR1L:CCP1CON<5:4>) •
TOSC • (TMR2 prescale value)
CCPR1L and CCP1CON<5:4> can be written to at any
time, but the duty cycle value is not latched into
CCPR1H until after a match between PR2 and TMR2
occurs (i.e., the period is complete). In PWM mode,
CCPR1H is a read-only register.
The CCPR1H register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitch-free PWM operation.
When the CCPR1H and 2-bit latch match TMR2, concatenated with an internal 2-bit Q clock, or 2 bits of the
TMR2 prescaler, the CCP1 pin is cleared.
The maximum PWM resolution (bits) for a given PWM
frequency is given by the formula:
Resolution
Duty Cycle
TMR2 = PR2
TMR2 = Duty Cycle
Note:
=
FOSC
log FPWM
(
log(2)
)
bits
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
TMR2 = PR2
DS30569B-page 58
 2003 Microchip Technology Inc.
PIC16F870/871
8.4.3
SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the CCP module for PWM operation:
1.
2.
3.
4.
5.
Set the PWM period by writing to the PR2
register.
Set the PWM duty cycle by writing to the
CCPR1L register and CCP1CON<5:4> bits.
Make the CCP1 pin an output by clearing the
TRISC<2> bit.
Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
Configure the CCP1 module for PWM operation.
TABLE 8-2:
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 20 MHz
PWM Frequency
1.22 kHz
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
TABLE 8-3:
4.88 kHz
19.53 kHz
78.12kHz
156.3 kHz
208.3 kHz
16
4
1
1
1
1
0xFFh
0xFFh
0xFFh
0x3Fh
0x1Fh
0x17h
10
10
10
8
7
6.5
REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, AND TIMER1
Value on
all other
RESETS
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
0Bh,8Bh,
INTCON
10Bh, 18Bh
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
TMR2IF
Address
0Ch
PIR1
PSPIF(1) ADIF
RCIF
TXIF
—
CCP1IF
8Ch
PIE1
PSPIE(1) ADIE
RCIE
TXIE
—
CCP1IE TMR2IE TMR1IE 0000 -000 0000 -000
87h
TRISC
PORTC Data Direction Register
1111 1111 1111 1111
0Eh
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
0Fh
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
10h
T1CON
15h
CCPR1L
Capture/Compare/PWM Register1 (LSB)
16h
CCPR1H
Capture/Compare/PWM Register1 (MSB)
17h
CCP1CON
Legend:
Note 1:
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by Capture and Timer1.
The PSP is not implemented on the PIC16F870; always maintain these bits clear.
—
—
 2003 Microchip Technology Inc.
—
—
TMR1IF 0000 -000 0000 -000
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
CCP1X
CCP1Y
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
DS30569B-page 59
PIC16F870/871
TABLE 8-4:
REGISTERS ASSOCIATED WITH PWM AND TIMER2
Value on
all other
RESETS
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
0Bh,8Bh,
INTCON
10Bh, 18Bh
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
Address
0Ch
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF 0000 -000 0000 -000
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE 0000 -000 0000 -000
87h
TRISC
PORTC Data Direction Register
1111 1111 1111 1111
11h
TMR2
Timer2 Module’s Register
0000 0000 0000 0000
92h
PR2
Timer2 Module’s Period Register
1111 1111 1111 1111
12h
T2CON
15h
CCPR1L
Capture/Compare/PWM Register1 (LSB)
xxxx xxxx uuuu uuuu
16h
CCPR1H
Capture/Compare/PWM Register1 (MSB)
xxxx xxxx uuuu uuuu
—
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
—
CCP1X
CCP1Y
CCP1M3
CCP1M2
CCP1M1 CCP1M0 --00 0000 --00 0000
17h
CCP1CON
Legend:
Note 1:
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PWM and Timer2.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
DS30569B-page 60
 2003 Microchip Technology Inc.
PIC16F870/871
9.0
ADDRESSABLE UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (USART)
The USART can be configured in the following modes:
• Asynchronous (full-duplex)
• Synchronous - Master (half-duplex)
• Synchronous - Slave (half-duplex)
The Universal Synchronous Asynchronous Receiver
Transmitter (USART) module is one of the two serial
I/O modules. (USART is also known as a Serial Communications Interface or SCI.) The USART can be configured as a full duplex asynchronous system that can
communicate with peripheral devices, such as CRT terminals and personal computers, or it can be configured
as a half-duplex synchronous system that can communicate with peripheral devices, such as A/D or D/A
integrated circuits, serial EEPROMs, etc.
REGISTER 9-1:
Bit SPEN (RCSTA<7>) and bits TRISC<7:6> have to
be set in order to configure pins RC6/TX/CK and
RC7/RX/DT
as
the
Universal
Synchronous
Asynchronous Receiver Transmitter.
The USART module also has a multi-processor
communication capability using 9-bit address
detection.
TXSTA: TRANSMIT STATUS AND CONTROL REGISTER (ADDRESS: 98h)
R/W-0
R/W-0
R/W-0
R/W-0
U-0
R/W-0
R-1
R/W-0
CSRC
TX9
TXEN
SYNC
—
BRGH
TRMT
TX9D
bit 7
bit 0
bit 7
CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6
TX9: 9-bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5
TXEN: Transmit Enable bit
1 = Transmit enabled
0 = Transmit disabled
Note:
SREN/CREN overrides TXEN in Sync mode.
bit 4
SYNC: USART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3
Unimplemented: Read as '0'
bit 2
BRGH: High Baud Rate Select bit
Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode
bit 1
TRMT: Transmit Shift Register Status bit
1 = TSR empty
0 = TSR full
bit 0
TX9D: 9th bit of Transmit Data, can be parity bit
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 61
PIC16F870/871
REGISTER 9-2:
RCSTA: RECEIVE STATUS AND CONTROL REGISTER (ADDRESS 18h)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R-0
R-x
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
bit 7
bit 0
bit 7
SPEN: Serial Port Enable bit
1 = Serial port enabled (configures RC7/RX/DT and RC6/TX/CK pins as serial port pins)
0 = Serial port disabled
bit 6
RX9: 9-bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5
SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care
Synchronous mode - master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode - slave:
Don’t care
bit 4
CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables continuous receive
0 = Disables continuous receive
Synchronous mode:
1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3
ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, enables interrupt and load of the receive buffer when
RSR<8> is set
0 = Disables address detection, all bytes are received, and ninth bit can be used as parity bit
bit 2
FERR: Framing Error bit
1 = Framing error (can be updated by reading RCREG register and receive next valid byte)
0 = No framing error
bit 1
OERR: Overrun Error bit
1 = Overrun error (can be cleared by clearing bit CREN)
0 = No overrun error
bit 0
RX9D: 9th bit of Received Data (can be parity bit, but must be calculated by user firmware)
Legend:
DS30569B-page 62
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
 2003 Microchip Technology Inc.
PIC16F870/871
9.1
USART Baud Rate Generator
(BRG)
It may be advantageous to use the high baud rate
(BRGH = 1), even for slower baud clocks. This is
because the FOSC/(16(X + 1)) equation can reduce the
baud rate error in some cases.
The BRG supports both the Asynchronous and Synchronous modes of the USART. It is a dedicated 8-bit
baud rate generator. The SPBRG register controls the
period of a free running 8-bit timer. In Asynchronous
mode, bit BRGH (TXSTA<2>) also controls the baud
rate. In Synchronous mode, bit BRGH is ignored.
Table 9-1 shows the formula for computation of the
baud rate for different USART modes which only apply
in Master mode (internal clock).
Writing a new value to the SPBRG register causes the
BRG timer to be reset (or cleared). This ensures the
BRG does not wait for a timer overflow before
outputting the new baud rate.
9.1.1
The data on the RC7/RX/DT pin is sampled three times
by a majority detect circuit to determine if a high or a
low level is present at the RX pin.
Given the desired baud rate and FOSC, the nearest
integer value for the SPBRG register can be calculated
using the formula in Table 9-1. From this, the error in
baud rate can be determined.
TABLE 9-1:
SAMPLING
BAUD RATE FORMULA
SYNC
BRGH = 0 (Low Speed)
BRGH = 1 (High Speed)
0
1
(Asynchronous) Baud Rate = FOSC/(64(X+1))
(Synchronous) Baud Rate = FOSC/(4(X+1))
Baud Rate = FOSC/(16(X+1))
N/A
Legend:
X = value in SPBRG (0 to 255)
TABLE 9-2:
Address
REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
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
98h
TXSTA
CSRC
TX9
TXEN
SYNC
—
BRGH
TRMT
TX9D
0000 -010
0000 -010
18h
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
99h
SPBRG
0000 0000
0000 0000
Legend:
x = unknown, - = unimplemented, read as '0'. Shaded cells are not used by the BRG.
Baud Rate Generator Register
 2003 Microchip Technology Inc.
DS30569B-page 63
PIC16F870/871
TABLE 9-3:
BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 0)
FOSC = 20 MHz
BAUD
RATE
(K)
%
ERROR
KBAUD
FOSC = 16 MHz
SPBRG
value
(decimal)
KBAUD
%
ERROR
FOSC = 10 MHz
SPBRG
value
(decimal)
KBAUD
%
ERROR
SPBRG
value
(decimal)
0.3
-
-
-
-
-
-
-
-
-
1.2
1.221
1.75
255
1.202
0.17
207
1.202
0.17
129
2.4
2.404
0.17
129
2.404
0.17
103
2.404
0.17
64
9.6
9.766
1.73
31
9.615
0.16
25
9.766
1.73
15
19.2
19.531
1.72
15
19.231
0.16
12
19.531
1.72
7
28.8
31.250
8.51
9
27.778
3.55
8
31.250
8.51
4
33.6
34.722
3.34
8
35.714
6.29
6
31.250
6.99
4
57.6
62.500
8.51
4
62.500
8.51
3
52.083
9.58
2
HIGH
1.221
-
255
0.977
-
255
0.610
-
255
LOW
312.500
-
0
250.000
-
0
156.250
-
0
FOSC = 4 MHz
BAUD
RATE
(K)
KBAUD
FOSC = 3.6864 MHz
%
ERROR
SPBRG
value
(decimal)
KBAUD
%
ERROR
SPBRG
value
(decimal)
0.3
0.300
0
207
0.3
0
191
1.2
1.202
0.17
51
1.2
0
47
2.4
2.404
0.17
25
2.4
0
23
9.6
8.929
6.99
6
9.6
0
5
19.2
20.833
8.51
2
19.2
0
2
28.8
31.250
8.51
1
28.8
0
1
33.6
-
-
-
-
-
-
57.6
62.500
8.51
0
57.6
0
0
HIGH
0.244
-
255
0.225
-
255
LOW
62.500
-
0
57.6
-
0
DS30569B-page 64
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 9-4:
BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 1)
FOSC = 20 MHz
FOSC = 16 MHz
BAUD
RATE
(K)
KBAUD
%
ERROR
SPBRG
value
(decimal)
0.3
-
-
1.2
-
-
2.4
-
FOSC = 10 MHz
KBAUD
%
ERROR
SPBRG
value
(decimal)
-
-
-
-
-
-
-
-
-
KBAUD
%
ERROR
SPBRG
value
(decimal)
-
-
-
-
-
-
-
-
-
-
2.441
1.71
255
9.6
9.615
0.16
129
9.615
0.16
103
9.615
0.16
64
19.2
19.231
0.16
64
19.231
0.16
51
19.531
1.72
31
28.8
29.070
0.94
42
29.412
2.13
33
28.409
1.36
21
33.6
33.784
0.55
36
33.333
0.79
29
32.895
2.10
18
57.6
59.524
3.34
20
58.824
2.13
16
56.818
1.36
10
HIGH
4.883
-
255
3.906
-
255
2.441
-
255
LOW
1250.000
-
0
1000.000
0
625.000
-
0
FOSC = 4 MHz
BAUD
RATE
(K)
KBAUD
FOSC = 3.6864 MHz
%
ERROR
SPBRG
value
(decimal)
KBAUD
%
ERROR
SPBRG
value
(decimal)
0.3
-
-
-
-
-
-
1.2
1.202
0.17
207
1.2
0
191
2.4
2.404
0.17
103
2.4
0
95
9.6
9.615
0.16
25
9.6
0
23
19.2
19.231
0.16
12
19.2
0
11
28.8
27.798
3.55
8
28.8
0
7
33.6
35.714
6.29
6
32.9
2.04
6
57.6
62.500
8.51
3
57.6
0
3
HIGH
0.977
-
255
0.9
-
255
LOW
250.000
-
0
230.4
-
0
 2003 Microchip Technology Inc.
DS30569B-page 65
PIC16F870/871
9.2
USART Asynchronous Mode
enabled/disabled by setting/clearing enable bit TXIE
( PIE1<4>). Flag bit TXIF will be set, regardless of the
state of enable bit TXIE and cannot be cleared in software. It will reset only when new data is loaded into the
TXREG register. While flag bit TXIF indicates the status
of the TXREG register, another bit, TRMT (TXSTA<1>),
shows the status of the TSR register. Status bit TRMT
is a read only bit, which is set when the TSR register is
empty. No interrupt logic is tied to this bit, so the user
has to poll this bit in order to determine if the TSR
register is empty.
In this mode, the USART uses standard non-return-tozero (NRZ) format (one START bit, eight or nine data
bits, and one STOP bit). The most common data format
is 8-bits. An on-chip, dedicated, 8-bit baud rate generator can be used to derive standard baud rate frequencies from the oscillator. The USART transmits and
receives the LSb first. The transmitter and receiver are
functionally independent, but use the same data format
and baud rate. The baud rate generator produces a
clock, either x16 or x64 of the bit shift rate, depending
on bit BRGH (TXSTA<2>). Parity is not supported by
the hardware, but can be implemented in software (and
stored as the ninth data bit). Asynchronous mode is
stopped during SLEEP.
Note 1: The TSR register is not mapped in data
memory, so it is not available to the user.
2: Flag bit TXIF is set when enable bit TXEN
is set. TXIF is cleared by loading TXREG.
Asynchronous mode is selected by clearing bit SYNC
(TXSTA<4>).
Transmission is enabled by setting enable bit TXEN
(TXSTA<5>). The actual transmission will not occur
until the TXREG register has been loaded with data
and the baud rate generator (BRG) has produced a
shift clock (Figure 9-2). The transmission can also be
started by first loading the TXREG register and then
setting enable bit TXEN. Normally, when transmission
is first started, the TSR register is empty. At that point,
transfer to the TXREG register will result in an immediate transfer to TSR, resulting in an empty TXREG. A
back-to-back transfer is thus possible (Figure 9-3).
Clearing enable bit TXEN during a transmission will
cause the transmission to be aborted and will reset the
transmitter. As a result, the RC6/TX/CK pin will revert
to hi-impedance.
The USART Asynchronous module consists of the
following important elements:
•
•
•
•
Baud Rate Generator
Sampling Circuit
Asynchronous Transmitter
Asynchronous Receiver
9.2.1
USART ASYNCHRONOUS
TRANSMITTER
The USART transmitter block diagram is shown in
Figure 9-1. The heart of the transmitter is the Transmit
(Serial) Shift register (TSR). The Shift register obtains
its data from the read/write transmit buffer, TXREG. The
TXREG register is loaded with data in software. The
TSR register is not loaded until the STOP bit has been
transmitted from the previous load. As soon as the
STOP bit is transmitted, the TSR is loaded with new
data from the TXREG register (if available). Once the
TXREG register transfers the data to the TSR register
(occurs in one TCY), the TXREG register is empty and
flag bit TXIF (PIR1<4>) is set. This interrupt can be
FIGURE 9-1:
In order to select 9-bit transmission, transmit bit TX9
(TXSTA<6>) should be set and the ninth bit should be
written to TX9D (TXSTA<0>). The ninth bit must be
written before writing the 8-bit data to the TXREG register. This is because a data write to the TXREG register can result in an immediate transfer of the data to the
TSR register (if the TSR is empty). In such a case, an
incorrect ninth data bit may be loaded in the TSR
register.
USART TRANSMIT BLOCK DIAGRAM
Data Bus
TXIF
TXREG Register
TXIE
8
MSb
(8)
• • •
LSb
0
Pin Buffer
and Control
TSR Register
RC6/TX/CK pin
Interrupt
TXEN
Baud Rate CLK
TRMT
SPEN
SPBRG
Baud Rate Generator
TX9
TX9D
DS30569B-page 66
 2003 Microchip Technology Inc.
PIC16F870/871
When setting up an Asynchronous Transmission,
follow these steps:
5.
1.
6.
Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH (Section 9.1).
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, then set enable bit
TXIE.
If 9-bit transmission is desired, then set transmit
bit TX9.
2.
3.
4.
FIGURE 9-2:
Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Load data to the TXREG register (starts
transmission).
If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
7.
8.
ASYNCHRONOUS MASTER TRANSMISSION
Write to TXREG
Word 1
BRG Output
(Shift Clock)
RC6/TX/CK (pin)
START Bit
Bit 0
Bit 1
Word 1
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
FIGURE 9-3:
Bit 7/8
STOP Bit
Word 1
Transmit Shift Reg
ASYNCHRONOUS MASTER TRANSMISSION (BACK TO BACK)
Write to TXREG
Word 2
Word 1
BRG Output
(Shift Clock)
RC6/TX/CK (pin)
START Bit
Bit 0
TXIF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Note:
Bit 7/8
Word 1
Transmit Shift Reg.
STOP Bit START Bit
Word 2
Bit 0
Word 2
Transmit Shift Reg.
This timing diagram shows two consecutive transmissions.
TABLE 9-5:
Address
Bit 1
Word 1
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
0000 -000
0000 -000
SPEN
RX9
SREN
CREN
—
FERR
OERR
RX9D
0000 -00x
0000 -00x
0Ch
PIR1
18h
RCSTA
19h
TXREG
8Ch
PIE1
98h
TXSTA
99h
SPBRG Baud Rate Generator Register
Legend:
Note 1:
x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for asynchronous transmission.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
USART Transmit Register
0000 0000
0000 0000
PSPIE(1)
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
0000 -000
0000 -000
CSRC
TX9
TXEN
SYNC
—
BRGH
TRMT
TX9D
0000 -010
0000 -010
0000 0000
0000 0000
 2003 Microchip Technology Inc.
DS30569B-page 67
PIC16F870/871
9.2.2
USART ASYNCHRONOUS
RECEIVER
is possible for two bytes of data to be received and
transferred to the RCREG FIFO and a third byte to
begin shifting to the RSR register. On the detection of
the STOP bit of the third byte, if the RCREG register is
still full, the overrun error bit OERR (RCSTA<1>) will be
set. The word in the RSR will be lost. The RCREG register can be read twice to retrieve the two bytes in the
FIFO. Overrun bit OERR has to be cleared in software.
This is done by resetting the receive logic (CREN is
cleared and then set). If bit OERR is set, transfers from
the RSR register to the RCREG register are inhibited,
and no further data will be received. It is therefore,
essential to clear error bit OERR if it is set. Framing
error bit FERR (RCSTA<2>) is set if a STOP bit is
detected as clear. Bit FERR and the 9th receive bit are
buffered the same way as the receive data. Reading
the RCREG will load bits RX9D and FERR with new
values, therefore, it is essential for the user to read the
RCSTA register before reading the RCREG register in
order not to lose the old FERR and RX9D information.
The receiver block diagram is shown in Figure 9-4. The
data is received on the RC7/RX/DT pin and drives the
data recovery block. The data recovery block is actually
a high speed shifter, operating at x16 times the baud
rate; whereas, the main receive serial shifter operates
at the bit rate or at FOSC.
Once Asynchronous mode is selected, reception is
enabled by setting bit CREN (RCSTA<4>).
The heart of the receiver is the Receive (Serial) Shift
register (RSR). After sampling the STOP bit, the
received data in the RSR is transferred to the RCREG
register (if it is empty). If the transfer is complete, flag
bit RCIF (PIR1<5>) is set. The actual interrupt can be
enabled/disabled by setting/clearing enable bit RCIE
(PIE1<5>). Flag bit RCIF is a read only bit, which is
cleared by the hardware. It is cleared when the RCREG
register has been read and is empty. The RCREG is a
double-buffered register (i.e., it is a two-deep FIFO). It
FIGURE 9-4:
USART RECEIVE BLOCK DIAGRAM
x64 Baud Rate CLK
OERR
FERR
CREN
FOSC
SPBRG
Baud Rate Generator
÷64
or
÷16
RSR Register
MSb
STOP (8)
• • •
7
1
LSb
0 START
RC7/RX/DT
Pin Buffer
and Control
Data
Recovery
RX9
RX9D
SPEN
Interrupt
RCREG Register
8
RCIF
Data Bus
RCIE
FIGURE 9-5:
RX (pin)
Rcv Shift
Reg
Rcv Buffer Reg
Read Rcv
Buffer Reg
RCREG
FIFO
ASYNCHRONOUS RECEPTION
START
bit
bit0
bit1
bit7/8 STOP
bit
START
bit
bit0
Word 1
RCREG
bit7/8 STOP
bit
START
bit
bit7/8
STOP
bit
Word 2
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN
Note:
This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
causing the OERR (overrun) bit to be set.
DS30569B-page 68
 2003 Microchip Technology Inc.
PIC16F870/871
When setting up an Asynchronous Reception, follow
these steps:
1.
2.
3.
4.
5.
6.
Flag bit RCIF will be set when reception is complete and an interrupt will be generated if enable
bit RCIE is set.
7. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
8. Read the 8-bit received data by reading the
RCREG register.
9. If any error occurred, clear the error by clearing
enable bit CREN.
10. If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH (Section 9.1).
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, then set enable bit
RCIE.
If 9-bit reception is desired, then set bit RX9.
Enable the reception by setting bit CREN.
TABLE 9-6:
Address
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
0Ch
PIR1
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
-000 0000
-000 0000
SPEN
RX9
SREN
CREN
—
0000 -00x
0000 -00x
0000 0000
0000 0000
0000 -000
0000 -000
0000 -010
0000 -010
0000 0000
0000 0000
18h
RCSTA
1Ah
RCREG USART Receive Register
8Ch
PIE1
98h
TXSTA
PSPIE(1)
ADIE
RCIE
TXIE
—
CSRC
TX9
TXEN
SYNC
—
Baud Rate Generator Register
CCP1IF TMR2IF TMR1IF
FERR
OERR
RX9D
CCP1IE TMR2IE TMR1IE
BRGH
TRMT
TX9D
99h
SPBRG
Legend:
Note 1:
x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for asynchronous reception.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
 2003 Microchip Technology Inc.
DS30569B-page 69
PIC16F870/871
9.2.3
SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
When setting up an Asynchronous Reception with
Address Detect enabled:
• Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired, set
bit BRGH.
• Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
• If interrupts are desired, then set enable bit RCIE.
• Set bit RX9 to enable 9-bit reception.
• Set ADDEN to enable address detect.
• Enable the reception by setting enable bit CREN.
FIGURE 9-6:
• Flag bit RCIF will be set when reception is complete, and an interrupt will be generated if enable
bit RCIE was set.
• Read the RCSTA register to get the ninth bit and
determine if any error occurred during reception.
• Read the 8-bit received data by reading the
RCREG register, to determine if the device is
being addressed.
• If any error occurred, clear the error by clearing
enable bit CREN.
• If the device has been addressed, clear the
ADDEN bit to allow data bytes and address bytes
to be read into the receive buffer, and interrupt the
CPU.
USART RECEIVE BLOCK DIAGRAM
x64 Baud Rate CLK
FERR
OERR
CREN
FOSC
SPBRG
÷ 64
Baud Rate Generator
RSR Register
MSb
or
÷ 16
STOP (8)
7
• • •
1
LSb
0 START
RC7/RX/DT
Pin Buffer
and Control
Data
Recovery
RX9
8
SPEN
RX9
ADDEN
Enable
Load of
RX9
ADDEN
RSR<8>
Receive
Buffer
8
RX9D
RCREG Register
FIFO
8
Interrupt
RCIF
Data Bus
RCIE
DS30569B-page 70
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 9-7:
ASYNCHRONOUS RECEPTION WITH ADDRESS DETECT
START
bit
bit0
RC7/RX/DT (pin)
bit1
bit8
STOP
bit
START
bit
bit0
bit8
STOP
bit
Load RSR
Bit8 = 0, Data Byte
Word 1
RCREG
Bit8 = 1, Address Byte
Read
RCIF
Note:
This timing diagram shows a data byte followed by an address byte. The data byte is not read into the RCREG (receive buffer)
because ADDEN = 1.
FIGURE 9-8:
ASYNCHRONOUS RECEPTION WITH ADDRESS BYTE FIRST
START
bit
bit0
RC7/RX/DT (pin)
bit1
bit8
STOP
bit
START
bit
bit0
bit8
STOP
bit
Load RSR
Bit8 = 1, Address Byte
Word 1
RCREG
Bit8 = 0, Data Byte
Read
RCIF
Note:
This timing diagram shows a data byte followed by an address byte. The data byte is not read into the RCREG (receive buffer)
because ADDEN was not updated and still = 0.
TABLE 9-7:
Address
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
0Ch
PIR1
18h
RCSTA
1Ah
RCREG
8Ch
PIE1
98h
TXSTA
99h
Legend:
Note 1:
SPBRG
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF TMR2IF TMR1IF 0000 -000
0000 -000
SPEN
RX9
SREN
CREN ADDEN
FERR
OERR
RX9D
USART Receive Register
PSPIE(1)
ADIE
RCIE
TXIE
—
CSRC
TX9
TXEN
SYNC
—
Baud Rate Generator Register
0000 000x
0000 000x
0000 0000
0000 0000
CCP1IE TMR2IE TMR1IE 0000 -000
0000 -000
BRGH
TRMT
TX9D
0000 -010
0000 -010
0000 0000
0000 0000
x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for asynchronous reception.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
 2003 Microchip Technology Inc.
DS30569B-page 71
PIC16F870/871
9.3
USART Synchronous
Master Mode
In Synchronous Master mode, the data is transmitted in
a half-duplex manner (i.e., transmission and reception
do not occur at the same time). When transmitting data,
the reception is inhibited and vice versa. Synchronous
mode is entered by setting bit SYNC (TXSTA<4>). In
addition, enable bit SPEN (RCSTA<7>) is set in order
to configure the RC6/TX/CK and RC7/RX/DT I/O pins
to CK (clock) and DT (data) lines, respectively. The
Master mode indicates that the processor transmits the
master clock on the CK line. The Master mode is
entered by setting bit CSRC (TXSTA<7>).
9.3.1
USART SYNCHRONOUS MASTER
TRANSMISSION
Clearing enable bit TXEN during a transmission will
cause the transmission to be aborted and will reset the
transmitter. The DT and CK pins will revert to hiimpedance. If either bit CREN or bit SREN is set during
a transmission, the transmission is aborted and the DT
pin reverts to a hi-impedance state (for a reception).
The CK pin will remain an output if bit CSRC is set
(internal clock). The transmitter logic, however, is not
reset, although it is disconnected from the pins. In order
to reset the transmitter, the user has to clear bit TXEN.
If bit SREN is set (to interrupt an on-going transmission
and receive a single word), then after the single word is
received, bit SREN will be cleared and the serial port
will revert back to transmitting, since bit TXEN is still
set. The DT line will immediately switch from HiImpedance Receive mode to transmit and start driving.
To avoid this, bit TXEN should be cleared.
The USART transmitter block diagram is shown in
Figure 9-6. The heart of the transmitter is the Transmit
(Serial) Shift register (TSR). The Shift register obtains
its data from the Read/Write Transmit Buffer register
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREG (if available). Once the
TXREG register transfers the data to the TSR register
(occurs in one TCYCLE), the TXREG is empty and interrupt bit TXIF (PIR1<4>) is set. The interrupt can be
enabled/disabled by setting/clearing enable bit TXIE
(PIE1<4>). Flag bit TXIF will be set, regardless of the
state of enable bit TXIE and cannot be cleared in software. It will reset only when new data is loaded into the
TXREG register. While flag bit TXIF indicates the status
of the TXREG register, another bit TRMT (TXSTA<1>)
shows the status of the TSR register. TRMT is a read
only bit which is set when the TSR is empty. No interrupt logic is tied to this bit, so the user has to poll this
bit in order to determine if the TSR register is empty.
The TSR is not mapped in data memory, so it is not
available to the user.
In order to select 9-bit transmission, the TX9
(TXSTA<6>) bit should be set and the ninth bit should
be written to bit TX9D (TXSTA<0>). The ninth bit must
be written before writing the 8-bit data to the TXREG
register. This is because a data write to the TXREG can
result in an immediate transfer of the data to the TSR
register (if the TSR is empty). If the TSR was empty and
the TXREG was written before writing the “new” TX9D,
the “present” value of bit TX9D is loaded.
Transmission is enabled by setting enable bit TXEN
(TXSTA<5>). The actual transmission will not occur
until the TXREG register has been loaded with data.
The first data bit will be shifted out on the next available
rising edge of the clock on the CK line. Data out is stable around the falling edge of the synchronous clock
(Figure 9-9). The transmission can also be started by
first loading the TXREG register and then setting bit
TXEN (Figure 9-10). This is advantageous when slow
baud rates are selected, since the BRG is kept in
RESET when bits TXEN, CREN and SREN are clear.
Setting enable bit TXEN will start the BRG, creating a
shift clock immediately. Normally, when transmission is
first started, the TSR register is empty, so a transfer to
the TXREG register will result in an immediate transfer
to TSR, resulting in an empty TXREG. Back-to-back
transfers are possible.
8.
DS30569B-page 72
Steps to follow when setting up a Synchronous Master
Transmission:
1.
2.
3.
4.
5.
6.
7.
Initialize the SPBRG register for the appropriate
baud rate (Section 9.1).
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set bit TX9.
Enable the transmission by setting bit TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 9-8:
Address
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
0000 -000
0000 -000
SPEN
RX9
SREN CREN
—
FERR
OERR
RX9D
0000 -00x
0000 -00x
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
0Ch
PIR1
18h
RCSTA
19h
TXREG
USART Transmit Register
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
98h
TXSTA
CSRC
TX9
TXEN
SYNC
—
99h
SPBRG
Legend:
Note 1:
CCP1IE TMR2IE TMR1IE
BRGH
TRMT
TX9D
Baud Rate Generator Register
0000 0000
0000 0000
0000 -000
0000 -000
0000 -010
0000 -010
0000 0000
0000 0000
x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for synchronous master transmission.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
FIGURE 9-9:
SYNCHRONOUS TRANSMISSION
Q1Q2 Q3Q4 Q1 Q2Q3 Q4Q1 Q2Q3 Q4Q1 Q2Q3 Q4Q1 Q2 Q3Q4
RC7/RX/DT pin
bit 0
bit 1
Q3Q4 Q1Q2 Q3Q4 Q1Q2 Q3Q4 Q1Q2 Q3 Q4Q1 Q2Q3 Q4Q1 Q2Q3 Q4Q1 Q2Q3 Q4
bit 2
bit 7
bit 0
bit 1
bit 7
Word 2
Word 1
RC6/TX/CK pin
Write to
TXREG reg
Write Word1
TXIF bit
(Interrupt Flag)
Write Word2
TRMT bit
'1'
TXEN bit
'1'
Note: Sync Master mode; SPBRG = 0. Continuous transmission of two 8-bit words.
FIGURE 9-10:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
RC7/RX/DT pin
bit0
bit1
bit2
bit6
bit7
RC6/TX/CK pin
Write to
TXREG Reg
TXIF bit
TRMT bit
TXEN bit
 2003 Microchip Technology Inc.
DS30569B-page 73
PIC16F870/871
9.3.2
USART SYNCHRONOUS MASTER
RECEPTION
Once Synchronous mode is selected, reception is
enabled by setting either enable bit SREN
(RCSTA<5>), or enable bit CREN (RCSTA<4>). Data is
sampled on the RC7/RX/DT pin on the falling edge of
the clock. If enable bit SREN is set, then only a single
word is received. If enable bit CREN is set, the reception is continuous until CREN is cleared. If both bits are
set, CREN takes precedence. After clocking the last bit,
the received data in the Receive Shift register (RSR) is
transferred to the RCREG register (if it is empty). When
the transfer is complete, interrupt flag bit RCIF
(PIR1<5>) is set. The actual interrupt can be enabled/
disabled by setting/clearing enable bit RCIE
(PIE1<5>). Flag bit RCIF is a read only bit, which is
reset by the hardware. In this case, it is reset when the
RCREG register has been read and is empty. The
RCREG is a double-buffered register (i.e., it is a twodeep FIFO). It is possible for two bytes of data to be
received and transferred to the RCREG FIFO and a
third byte to begin shifting into the RSR register. On the
clocking of the last bit of the third byte, if the RCREG
register is still full, then overrun error bit OERR
(RCSTA<1>) is set. The word in the RSR will be lost.
The RCREG register can be read twice to retrieve the
two bytes in the FIFO. Bit OERR has to be cleared in
software (by clearing bit CREN). If bit OERR is set,
transfers from the RSR to the RCREG are inhibited, so
it is essential to clear bit OERR if it is set. The ninth
receive bit is buffered the same way as the receive
data. Reading the RCREG register will load bit RX9D
with a new value, therefore, it is essential for the user
to read the RCSTA register before reading RCREG, in
order not to lose the old RX9D information.
DS30569B-page 74
When setting up a Synchronous Master Reception:
1.
Initialize the SPBRG register for the appropriate
baud rate (Section 9.1).
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
3. Ensure bits CREN and SREN are clear.
4. If interrupts are desired, then set enable bit
RCIE.
5. If 9-bit reception is desired, then set bit RX9.
6. If a single reception is required, set bit SREN.
For continuous reception, set bit CREN.
7. Interrupt flag bit RCIF will be set when reception
is complete and an interrupt will be generated if
enable bit RCIE was set.
8. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
10. If any error occurred, clear the error by clearing
bit CREN.
11. If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 9-9:
Address
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
0000 -000
0000 -000
SPEN
RX9
SREN CREN
—
FERR
OERR
RX9D
0000 -00x
0000 -00x
0Ch
PIR1
18h
RCSTA
1Ah
RCREG
USART Receive Register
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
98h
TXSTA
CSRC
TX9
TXEN
SYNC
—
99h
SPBRG
Legend:
Note 1:
CCP1IE TMR2IE TMR1IE
BRGH
TRMT
TX9D
Baud Rate Generator Register
0000 0000
0000 0000
0000 -000
0000 -000
0000 -010
0000 -010
0000 0000
0000 0000
x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for synchronous master reception.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
FIGURE 9-11:
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX/DT pin
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
RC6/TX/CK pin
Write to
bit SREN
SREN bit
CREN bit
'0'
'0'
RCIF bit
(Interrupt)
Read
RXREG
Note: Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRG = 0.
 2003 Microchip Technology Inc.
DS30569B-page 75
PIC16F870/871
9.4
USART Synchronous Slave Mode
When setting up a Synchronous Slave Transmission,
follow these steps:
Synchronous Slave mode differs from the Master mode
in the fact that the shift clock is supplied externally at
the RC6/TX/CK pin (instead of being supplied internally
in Master mode). This allows the device to transfer or
receive data while in SLEEP mode. Slave mode is
entered by clearing bit CSRC (TXSTA<7>).
9.4.1
1.
2.
3.
USART SYNCHRONOUS SLAVE
TRANSMIT
4.
5.
The operation of the Synchronous Master and Slave
modes is identical, except in the case of the SLEEP mode.
6.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
7.
a)
b)
c)
d)
e)
The first word will immediately transfer to the
TSR register and transmit.
The second word will remain in TXREG register.
Flag bit TXIF will not be set.
When the first word has been shifted out of TSR,
the TXREG register will transfer the second word
to the TSR and flag bit TXIF will now be set.
If enable bit TXIE is set, the interrupt will wake
the chip from SLEEP and if the global interrupt
is enabled, the program will branch to the
interrupt vector (0004h).
TABLE 9-10:
Address
8.
REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
SPEN
RX9
SREN
CREN
ADDEN
0Ch
PIR1
18h
RCSTA
19h
TXREG
USART Transmit Register
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
98h
TXSTA
CSRC
TX9
TXEN
SYNC
—
99h
Legend:
Note 1:
Enable the synchronous slave serial port by setting bits SYNC and SPEN and clearing bit
CSRC.
Clear bits CREN and SREN.
If interrupts are desired, then set enable bit
TXIE.
If 9-bit transmission is desired, then set bit TX9.
Enable the transmission by setting enable bit
TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
SPBRG
Baud Rate Generator Register
CCP1IF TMR2IF TMR1IF 0000 -000
FERR
OERR
RX9D
0000 000x
0000 -000
0000 000x
0000 0000
0000 0000
CCP1IE TMR2IE TMR1IE 0000 -000
0000 -000
BRGH
TRMT
TX9D
0000 -010
0000 -010
0000 0000
0000 0000
x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for synchronous slave transmission.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
DS30569B-page 76
 2003 Microchip Technology Inc.
PIC16F870/871
9.4.2
USART SYNCHRONOUS SLAVE
RECEPTION
When setting up a Synchronous Slave Reception,
follow these steps:
The operation of the Synchronous Master and Slave
modes is identical, except in the case of the SLEEP
mode. Bit SREN is a “don't care” in Slave mode.
1.
If receive is enabled by setting bit CREN prior to the
SLEEP instruction, then a word may be received during
SLEEP. On completely receiving the word, the RSR
register will transfer the data to the RCREG register
and if enable bit RCIE bit is set, the interrupt generated
will wake the chip from SLEEP. If the global interrupt is
enabled, the program will branch to the interrupt vector
(0004h).
2.
3.
4.
5.
6.
7.
8.
9.
TABLE 9-11:
Address
REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name
0Bh, 8Bh, INTCON
10Bh,18Bh
0Ch
PIR1
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
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
R0IF
0000 000x
0000 000u
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
18h
RCSTA
1Ah
RCREG
USART Receive Register
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
98h
TXSTA
CSRC
TX9
TXEN
SYNC
—
99h
Legend:
Note 1:
Enable the synchronous master serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
If interrupts are desired, set enable bit RCIE.
If 9-bit reception is desired, set bit RX9.
To enable reception, set enable bit CREN.
Flag bit RCIF will be set when reception is complete and an interrupt will be generated, if
enable bit RCIE was set.
Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
Read the 8-bit received data by reading the
RCREG register.
If any error occurred, clear the error by clearing
bit CREN.
If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
SPBRG
TMR1IF 0000 -000 0000 -000
RX9D
0000 000x 0000 000x
0000 0000 0000 0000
Baud Rate Generator Register
CCP1IE TMR2IE TMR1IE 0000 -000 0000 -000
BRGH
TRMT
TX9D
0000 -010 0000 -010
0000 0000 0000 0000
x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for synchronous slave reception.
Bits PSPIE and PSPIF are reserved on the PIC16F870, always maintain these bits clear.
 2003 Microchip Technology Inc.
DS30569B-page 77
PIC16F870/871
NOTES:
DS30569B-page 78
 2003 Microchip Technology Inc.
PIC16F870/871
10.0
ANALOG-TO-DIGITAL (A/D)
CONVERTER MODULE
The A/D module has four registers. These registers
are:
The Analog-to-Digital (A/D) Converter module has five
inputs for the 28-pin devices and eight for the other
devices.
The analog input charges a sample and hold capacitor.
The output of the sample and hold capacitor is the input
into the converter. The converter then generates a digital result of this analog level via successive approximation. The A/D conversion of the analog input signal
results in a corresponding 10-bit digital number. The
A/D module has high and low voltage reference input
that is software selectable to some combination of VDD,
VSS, RA2, or RA3.
The A/D converter has a unique feature of being able
to operate while the device is in SLEEP mode. To operate in SLEEP, the A/D clock must be derived from the
A/D’s internal RC oscillator.
REGISTER 10-1:
•
•
•
•
A/D Result High Register (ADRESH)
A/D Result Low Register (ADRESL)
A/D Control Register0 (ADCON0)
A/D Control Register1 (ADCON1)
The ADCON0 register, shown in Register 10-1, controls the operation of the A/D module. The ADCON1
register, shown in Register 10-2, configures the functions of the port pins. The port pins can be configured
as analog inputs (RA3 can also be the voltage
reference), or as digital I/O.
Additional information on using the A/D module can be
found in the PICmicro™ Mid-Range MCU Family
Reference Manual (DS33023).
ADCON0 REGISTER (ADDRESS: 1Fh)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
U-0
R/W-0
ADCS1
ADCS0
CHS2
CHS1
CHS0
GO/DONE
—
ADON
bit 7
bit 0
bit 7-6
ADCS1:ADCS0: A/D Conversion Clock Select bits
00 = FOSC/2
01 = FOSC/8
10 = FOSC/32
11 = FRC (clock derived from the internal A/D module RC oscillator)
bit 5-3
CHS2:CHS0: Analog Channel Select bits
000 = Channel 0, (RA0/AN0)
010 = Channel 2, (RA2/AN2)
011 = Channel 3, (RA3/AN3)
100 = Channel 4, (RA5/AN4)
101 = Channel 5, (RE0/AN5)(1)
110 = Channel 6, (RE1/AN6)(1)
111 = Channel 7, (RE2/AN7)(1)
bit 2
GO/DONE: A/D Conversion Status bit
If ADON = 1:
1 = A/D conversion in progress (setting this bit starts the A/D conversion)
0 = A/D conversion not in progress (this bit is automatically cleared by hardware when the A/D
conversion is complete)
bit 1
Unimplemented: Read as '0'
bit 0
ADON: A/D On bit
1 = A/D converter module is operating
0 = A/D converter module is shut-off and consumes no operating current
Note 1: These channels are not available on the PIC16F870 device.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
 2003 Microchip Technology Inc.
x = Bit is unknown
DS30569B-page 79
PIC16F870/871
REGISTER 10-2:
ADCON1 REGISTER (ADDRESS: 9Fh)
U-0
U-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
ADFM
—
—
—
PCFG3
PCFG2
PCFG1
PCFG0
bit 7
bit 0
bit 7
ADFM: A/D Result Format Select bit
1 = Right justified. 6 Most Significant bits of ADRESH are read as ‘0’.
0 = Left justified. 6 Least Significant bits of ADRESL are read as ‘0’.
bit 6-4
Unimplemented: Read as '0'
bit 3-0
PCFG3:PCFG0: A/D Port Configuration Control bits:
PCFG3: AN7(1) AN6(1) AN5(1)
RE2
RE1
RE0
PCFG0
AN4
RA5
AN3
RA3
AN2
RA2
AN1
RA1
AN0
RA0
VREF+
VREF-
CHAN/
Refs(2)
0000
A
A
A
A
A
A
A
A
VDD
VSS
8/0
0001
A
A
A
A
VREF+
A
A
A
RA3
VSS
7/1
0010
D
D
D
A
A
A
A
A
VDD
VSS
5/0
0011
D
D
D
A
VREF+
A
A
A
RA3
VSS
4/1
0100
D
D
D
D
A
D
A
A
VDD
VSS
3/0
0101
D
D
D
D
VREF+
D
A
A
RA3
VSS
2/1
011x
D
D
D
D
D
D
D
D
VDD
VSS
0/0
1000
A
A
A
A
VREF+
VREF-
A
A
RA3
RA2
6/2
1001
D
D
A
A
A
A
A
A
VDD
VSS
6/0
1010
D
D
A
A
VREF+
A
A
A
RA3
VSS
5/1
1011
D
D
A
A
VREF+
VREF-
A
A
RA3
RA2
4/2
1100
D
D
D
A
VREF+
VREF-
A
A
RA3
RA2
3/2
1101
D
D
D
D
VREF+
VREF-
A
A
RA3
RA2
2/2
1110
D
D
D
D
D
D
D
A
VDD
VSS
1/0
1111
D
D
D
D
VREF+
VREF-
D
A
RA3
RA2
1/2
A = Analog input
D = Digital I/O
Note 1: These channels are not available on the PIC16F870 device.
2: This column indicates the number of analog channels available as A/D inputs and
the number of analog channels used as voltage reference inputs.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
The ADRESH:ADRESL registers contain the 10-bit
result of the A/D conversion. When the A/D conversion
is complete, the result is loaded into this A/D result register pair, the GO/DONE bit (ADCON0<2>) is cleared
and the A/D interrupt flag bit ADIF is set. The block
diagram of the A/D module is shown in Figure 10-1.
x = Bit is unknown
To determine sample time, see Section 10.1. After this
acquisition time has elapsed, the A/D conversion can
be started.
After the A/D module has been configured as desired,
the selected channel must be acquired before the conversion is started. The analog input channels must
have their corresponding TRIS bits selected as inputs.
DS30569B-page 80
 2003 Microchip Technology Inc.
PIC16F870/871
These steps should be followed for doing an A/D
Conversion:
1.
2.
3.
4.
Configure the A/D module:
• Configure analog pins/voltage reference and
digital I/O (ADCON1)
• Select A/D input channel (ADCON0)
• Select A/D conversion clock (ADCON0)
• Turn on A/D module (ADCON0)
Configure A/D interrupt (if desired):
• Clear ADIF bit
• Set ADIE bit
• Set PEIE bit
• Set GIE bit
FIGURE 10-1:
5.
6.
7.
Wait the required acquisition time.
Start conversion:
• Set GO/DONE bit (ADCON0)
Wait for A/D conversion to complete, by either:
• Polling for the GO/DONE bit to be cleared
(with interrupts enabled); OR
• Waiting for the A/D interrupt
Read
A/D
Result
register
pair
(ADRESH:ADRESL), clear bit ADIF if required.
For the next conversion, go to step 1 or step 2,
as required. The A/D conversion time per bit is
defined as TAD. A minimum wait of 2 TAD is
required before the next acquisition starts.
A/D BLOCK DIAGRAM
CHS2:CHS0
111
110
101
RE2/AN7(1)
RE1/AN6(1)
RE0/AN5(1)
100
RA5/AN4
VAIN
011
(Input Voltage)
RA3/AN3/VREF+
010
RA2/AN2/VREF-
A/D
Converter
001
RA1/AN1
VDD
000
RA0/AN0
VREF+
(Reference
Voltage)
PCFG3:PCFG0
VREF(Reference
Voltage)
VSS
PCFG3:PCFG0
Note 1: Not available on the PIC16F870 device.
 2003 Microchip Technology Inc.
DS30569B-page 81
PIC16F870/871
10.1
A/D Acquisition Requirements
For the A/D converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 10-2. The
source impedance (RS) and the internal sampling
switch (RSS) impedance directly affect the time
required to charge the capacitor CHOLD. The sampling
switch (RSS) impedance varies over the device voltage
(VDD), see Figure 10-2. The maximum recommended impedance for analog sources is 10 kΩ. As
the impedance is decreased, the acquisition time may
EQUATION 10-1:
TACQ
TC
TACQ
be decreased. After the analog input channel is
selected (changed), this acquisition must be done
before the conversion can be started.
To calculate the minimum acquisition time,
Equation 10-1 may be used. This equation assumes
that 1/2 LSb error is used (1024 steps for the A/D). The
1/2 LSb error is the maximum error allowed for the A/D
to meet its specified resolution.
To calculate the minimum acquisition time, TACQ, see
the PICmicro™ Mid-Range MCU Family Reference
Manual (DS33023).
ACQUISITION TIME
= Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
=
=
=
=
=
=
=
TAMP + TC + TCOFF
2 µs + TC + [(Temperature – 25°C)(0.05 µs/°C)]
CHOLD (RIC + RSS + RS) In(1/2047)
- 120 pF (1 kΩ + 7 kΩ + 10 kΩ) In(0.0004885)
16.47 µs
2 µs + 16.47 µs + [(50°C – 25°C)(0.05 µs/°C)
19.72 µs
Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out.
2: The charge holding capacitor (CHOLD) is not discharged after each conversion.
3: The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the pin
leakage specification.
4: After a conversion has completed, a 2.0 TAD delay must complete before acquisition can begin again.
During this time, the holding capacitor is not connected to the selected A/D input channel.
FIGURE 10-2:
ANALOG INPUT MODEL
VDD
RS
VA
ANx
CPIN
5 pF
VT = 0.6V
VT = 0.6V
RIC ≤ 1k
Sampling
Switch
SS RSS
CHOLD
= DAC capacitance
= 120 pF
I LEAKAGE
± 500 nA
VSS
Legend CPIN
= input capacitance
VT
= threshold voltage
I LEAKAGE = leakage current at the pin due to
various junctions
RIC
= interconnect resistance
SS
= sampling switch
CHOLD
= sample/hold capacitance (from DAC)
DS30569B-page 82
6V
5V
VDD 4V
3V
2V
5 6 7 8 9 10 11
Sampling Switch
(kΩ)
 2003 Microchip Technology Inc.
PIC16F870/871
10.2
Selecting the A/D Conversion
Clock
For correct A/D conversions, the A/D conversion clock
(TAD) must be selected to ensure a minimum TAD time
of 1.6 µs.
The A/D conversion time per bit is defined as TAD. The
A/D conversion requires a minimum 12 TAD per 10-bit
conversion. The source of the A/D conversion clock is
software selected. The four possible options for TAD
are:
•
•
•
•
Table 10-1 shows the resultant TAD times derived from
the device operating frequencies and the A/D clock
source selected.
2 TOSC
8 TOSC
32 TOSC
Internal A/D module RC oscillator (2-6 µs)
TABLE 10-1:
TAD vs. MAXIMUM DEVICE OPERATING FREQUENCIES (STANDARD DEVICES (C))
AD Clock Source (TAD)
Note 1:
2:
3:
10.3
Maximum Device Frequency
Operation
ADCS1:ADCS0
Max.
2 TOSC
00
1.25 MHz
8 TOSC
01
5 MHz
32 TOSC
10
20 MHz
RC(1, 2, 3)
11
(Note 1)
The RC source has a typical TAD time of 4 µs, but can vary between 2-6 µs.
When the device frequencies are greater than 1 MHz, the RC A/D conversion clock source is only
recommended for SLEEP operation.
For extended voltage devices (LC), please refer to the Electrical Characteristics (Section 14.1 and 14.2).
Configuring Analog Port Pins
The ADCON1 and TRIS registers control the operation
of the A/D port pins. The port pins that are desired as
analog inputs must have their corresponding TRIS bits
set (input). If the TRIS bit is cleared (output), the digital
output level (VOH or VOL) will be converted.
The A/D operation is independent of the state of the
CHS2:CHS0 bits and the TRIS bits.
 2003 Microchip Technology Inc.
Note 1: When reading the port register, any pin
configured as an analog input channel will
read as cleared (a low level). Pins configured as digital inputs will convert an analog input. Analog levels on a digitally
configured input will not affect the
conversion accuracy.
2: Analog levels on any pin that is defined as
a digital input (including the AN7:AN0
pins), may cause the input buffer to consume current that is out of the device
specifications.
DS30569B-page 83
PIC16F870/871
10.4
A/D Conversions
acquisition is started. After this 2 TAD wait, acquisition
on the selected channel is automatically started. The
GO/DONE bit can then be set to start the conversion.
Clearing the GO/DONE bit during a conversion will
abort the current conversion. The A/D result register
pair will NOT be updated with the partially completed
A/D conversion sample. That is, the ADRESH:ADRESL
registers will continue to contain the value of the last
completed conversion (or the last value written to the
ADRESH:ADRESL registers). After the A/D conversion
is aborted, a 2 TAD wait is required before the next
FIGURE 10-3:
In Figure 10-3, after the GO bit is set, the first time
segment has a minimum of TCY and a maximum of TAD.
Note:
The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
A/D CONVERSION TAD CYCLES
TCY to TAD TAD1
TAD2
TAD3
TAD4
TAD5
TAD6
TAD7
TAD8
b9
b8
b7
b6
b5
b4
b3
TAD9 TAD10 TAD11
b2
b1
b0
Conversion starts
Holding capacitor is disconnected from analog input (typically 100 ns)
Set GO bit
10.4.1
ADRES is loaded
GO bit is cleared
ADIF bit is set
Holding capacitor is connected to analog input
A/D RESULT REGISTERS
The ADRESH:ADRESL register pair is the location
where the 10-bit A/D result is loaded at the completion of
the A/D conversion. This register pair is 16-bits wide.
The A/D module gives the flexibility to left or right justify
the 10-bit result in the 16-bit result register. The A/D For-
FIGURE 10-4:
mat Select bit (ADFM) controls this justification.
Figure 10-4 shows the operation of the A/D result justification. The extra bits are loaded with ‘0’. When an A/D
result will not overwrite these locations (A/D disable),
these registers may be used as two general purpose
8-bit registers.
A/D RESULT JUSTIFICATION
10-bit Result
ADFM = 0
ADFM = 1
7
0
2107
7
0765
0000 00
0000 00
ADRESH
ADRESL
10-bit Result
Right Justified
DS30569B-page 84
0
ADRESH
ADRESL
10-bit Result
Left Justified
 2003 Microchip Technology Inc.
PIC16F870/871
10.5
A/D Operation During SLEEP
Turning off the A/D places the A/D module in its lowest
current consumption state.
The A/D module can operate during SLEEP mode. This
requires that the A/D clock source be set to RC
(ADCS1:ADCS0 = 11). When the RC clock source is
selected, the A/D module waits one instruction cycle
before starting the conversion. This allows the SLEEP
instruction to be executed, which eliminates all digital
switching noise from the conversion. When the conversion is completed, the GO/DONE bit will be cleared and
the result loaded into the ADRES register. If the A/D
interrupt is enabled, the device will wake-up from
SLEEP. If the A/D interrupt is not enabled, the A/D module will then be turned off, although the ADON bit will
remain set.
Note:
10.6
Effects of a RESET
A device RESET forces all registers to their RESET
state. This forces the A/D module to be turned off, and
any conversion is aborted. All A/D input pins are
configured as analog inputs.
When the A/D clock source is another clock option (not
RC), a SLEEP instruction will cause the present conversion to be aborted and the A/D module to be turned off,
though the ADON bit will remain set.
TABLE 10-2:
For the A/D module to operate in SLEEP,
the A/D clock source must be set to RC
(ADCS1:ADCS0 = 11). To allow the conversion to occur during SLEEP, ensure the
SLEEP instruction immediately follows the
instruction that sets the GO/DONE bit.
The value that is in the ADRESH:ADRESL registers is
not modified for a Power-on Reset. The
ADRESH:ADRESL registers will contain unknown data
after a Power-on Reset.
REGISTERS/BITS ASSOCIATED WITH A/D
Value on
MCLR,
WDT
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
0Bh,8Bh,
INTCON
10Bh,18Bh
GIE
PEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
Address
0Ch
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF TMR1IF 0000 -000 0000 -000
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE TMR1IE 0000 -000 0000 -000
1Eh
ADRESH
A/D Result Register High Byte
xxxx xxxx uuuu uuuu
9Eh
ADRESL
A/D Result Register Low Byte
xxxx xxxx uuuu uuuu
CHS0
GO/DONE
—
ADON
0000 00-0 0000 00-0
—
PCFG3
PCFG2
PCFG1
PCFG0
--0- 0000
ADCON0
ADCS1
ADCON1
ADFM
—
85h
TRISA
—
—
PORTA Data Direction Register
--11 1111 --11 1111
05h
PORTA
—
—
PORTA Data Latch when written: PORTA pins when read
--0x 0000 --0u 0000
89h(1)
TRISE
IBF
OBF
IBOV
PSPMODE
—
09h(1)
PORTE
—
—
—
—
—
Legend:
Note 1:
x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used for A/D conversion.
These registers/bits are not available on the 28-pin devices.
 2003 Microchip Technology Inc.
ADCS0 CHS2
CHS1
1Fh
9Fh
—
PORTE Data Direction bits
RE2
RE1
RE0
--0- 0000
0000 -111 0000 -111
---- -xxx ---- -uuu
DS30569B-page 85
PIC16F870/871
NOTES:
DS30569B-page 86
 2003 Microchip Technology Inc.
PIC16F870/871
11.0
SPECIAL FEATURES OF THE
CPU
The PIC16F870/871 devices have a host of features
intended to maximize system reliability, minimize cost
through elimination of external components, provide
Power Saving Operating modes and offer code
protection. These are:
• Oscillator Selection
• RESET
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• SLEEP
• Code Protection
• ID Locations
• In-Circuit Serial Programming
• Low Voltage In-Circuit Serial Programming
• In-Circuit Debugger
SLEEP mode is designed to offer a very low current
Power-down mode. The user can wake-up from
SLEEP through external RESET, Watchdog Timer
Wake-up, or through an interrupt.
Several oscillator options are also made available to
allow the part to fit the application. The RC oscillator
option saves system cost while the LP crystal option
saves power. A set of configuration bits is used to
select various options.
Additional information on special features is available
in the PICmicro™ Mid-Range MCU Family Reference
Manual (DS33023).
11.1
Configuration Bits
The configuration bits can be programmed (read as '0'),
or left unprogrammed (read as '1'), to select various
device configurations. The erased, or unprogrammed
value of the configuration word is 3FFFh. These bits
are mapped in program memory location 2007h.
It is important to note that address 2007h is beyond the
user program memory space, which can be accessed
only during programming.
PIC16F870/871 devices have a Watchdog Timer,
which can be shut-off only through configuration bits. It
runs off its own RC oscillator for 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 Power-up Timer
(PWRT), which provides a fixed delay of 72 ms (nominal) on power-up only. It is designed to keep the part in
RESET while the power supply stabilizes. With these
two timers on-chip, most applications need no external
RESET circuitry.
 2003 Microchip Technology Inc.
DS30569B-page 87
PIC16F870/871
REGISTER 11-1:
CP1
CP0
CONFIGURATION WORD (ADDRESS 2007h)(1)
DEBUG
—
WRT CPD LVP
BOREN
CP1
CP0
PWRTEN WDTEN FOSC1 FOSC0
bit 13
bit 0
(2)
bit 13-12,
bit 5-4
CP1:CP0: FLASH Program Memory Code Protection bits
11 = Code protection off
10 = Not supported
01 = Not supported
00 = Code protection on
bit 11
DEBUG: In-Circuit Debugger Mode
1 = In-Circuit Debugger disabled, RB6 and RB7 are general purpose I/O pins
0 = In-Circuit Debugger enabled, RB6 and RB7 are dedicated to the debugger
bit 10
Unimplemented: Read as ‘1’
bit 9
WRT: FLASH Program Memory Write Enable
1 = Unprotected program memory may be written to by EECON control
0 = Unprotected program memory may not be written to by EECON control
bit 8
CPD: Data EE Memory Code Protection
1 = Code protection off
0 = Data EEPROM memory code protected
bit 7
LVP: Low Voltage In-Circuit Serial Programming Enable bit
1 = RB3/PGM pin has PGM function, low voltage programming enabled
0 = RB3 is digital I/O, HV on MCLR must be used for programming
bit 6
BOREN: Brown-out Reset Enable bit(3)
1 = BOR enabled
0 = BOR disabled
bit 3
PWRTEN: Power-up Timer Enable bit(3)
1 = PWRT disabled
0 = PWRT enabled
bit 2
WDTEN: 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
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
Note 1: The erased (unprogrammed) value of the configuration word is 3FFFh.
2: All of the CP1:CP0 pairs have to be given the same value to enable the code protection scheme listed.
3: Enabling Brown-out Reset automatically enables Power-up Timer (PWRT), regardless of the value of bit
PWRTEN. Ensure the Power-up Timer is enabled any time Brown-out Reset is enabled.
DS30569B-page 88
 2003 Microchip Technology Inc.
PIC16F870/871
11.2
FIGURE 11-2:
Oscillator Configurations
11.2.1
OSCILLATOR TYPES
The PIC16F870/871 can be operated in four different
Oscillator modes. The user can program two configuration bits (FOSC1 and FOSC0) to select one of these
four modes:
•
•
•
•
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
LP
XT
HS
RC
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
11.2.2
In XT, LP or HS modes, a crystal or ceramic resonator
is connected to the OSC1/CLKI and OSC2/CLKO pins
to establish oscillation (Figure 11-1). The PIC16F870/
871 oscillator design requires the use of a parallel cut
crystal. Use of a series cut crystal may give a frequency
out of the crystal manufacturers specifications. When in
XT, LP or HS modes, the device can have an external
clock source to drive the OSC1/CLKI pin (Figure 11-2).
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
OSC CONFIGURATION)
C1(1)
OSC1
XTAL
RF(3)
OSC2
C2(1)
Note 1:
2:
3:
Rs
(2)
PIC16F870/871
OSC2
Open
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
FIGURE 11-1:
OSC1
Clock from
Ext. System
To
Internal
Logic
SLEEP
TABLE 11-1:
CERAMIC RESONATORS
Ranges Tested:
Mode
Freq.
OSC1
OSC2
XT
455 kHz
2.0 MHz
4.0 MHz
68 - 100 pF
15 - 68 pF
15 - 68 pF
68 - 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
These values are for design guidance only.
See notes following Table 11-2.
Resonators Used:
455 kHz
Panasonic EFO-A455K04B
± 0.3%
2.0 MHz
Murata Erie CSA2.00MG
± 0.5%
4.0 MHz
Murata Erie CSA4.00MG
± 0.5%
8.0 MHz
Murata Erie CSA8.00MT
± 0.5%
16.0 MHz
Murata Erie CSA16.00MX
± 0.5%
All resonators used did not have built-in capacitors.
PIC16F870/871
See Table 11-1 and Table 11-2 for
recommended values of C1 and C2.
A series resistor (Rs) may be required for
AT strip cut crystals.
RF varies with the crystal chosen.
 2003 Microchip Technology Inc.
DS30569B-page 89
PIC16F870/871
TABLE 11-2:
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Osc Type
Crystal
Freq.
Cap. Range
C1
Cap. Range
C2
LP
32 kHz
33 pF
33 pF
200 kHz
15 pF
15 pF
200 kHz
47-68 pF
47-68 pF
1 MHz
15 pF
15 pF
4 MHz
15 pF
15 pF
4 MHz
15 pF
15 pF
8 MHz
15-33 pF
15-33 pF
20 MHz
15-33 pF
15-33 pF
XT
HS
These values are for design guidance only.
See notes following this table.
11.2.3
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 package 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 11-3 shows how the R/C
combination is connected to the PIC16F870/871.
FIGURE 11-3:
RC OSCILLATOR MODE
VDD
Crystals Used
32 kHz
Epson C-001R32.768K-A
± 20 PPM
200 kHz
STD XTL 200.000KHz
± 20 PPM
1 MHz
ECS ECS-10-13-1
± 50 PPM
4 MHz
ECS ECS-40-20-1
± 50 PPM
CEXT
VSS
8 MHz
EPSON CA-301 8.000M-C
± 30 PPM
20 MHz
EPSON CA-301 20.000M-C
± 30 PPM
Note 1: Higher capacitance increases the stability
of oscillator, but also increases the
start-up time.
REXT
OSC1
Internal
Clock
PIC16F870/871
FOSC/4
OSC2/CLKO
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
CEXT > 20pF
2: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate values of external components.
3: Rs may be required in HS mode, as well
as XT mode, to avoid overdriving crystals
with low drive level specification.
4: When migrating from other PICmicro®
devices, oscillator performance should be
verified.
DS30569B-page 90
 2003 Microchip Technology Inc.
PIC16F870/871
11.3
RESET
The PIC16F870/871 differentiates between various
kinds of RESET:
•
•
•
•
•
•
Power-on Reset (POR)
MCLR Reset during normal operation
MCLR Reset during SLEEP
WDT Reset (during normal operation)
WDT Wake-up (during SLEEP)
Brown-out Reset (BOR)
Some registers are not affected in any RESET condition. Their status is unknown on POR and unchanged
in any other RESET. Most other registers are reset to a
“RESET state” on Power-on Reset (POR), on the
MCLR and WDT Reset, on MCLR Reset during
FIGURE 11-4:
SLEEP, and Brown-out Reset (BOR). They are not
affected by a WDT Wake-up, which is viewed as the
resumption of normal operation. The TO and PD bits
are set or cleared differently in different RESET situations, as indicated in Table 11-4. These bits are used in
software to determine the nature of the RESET. See
Table 11-6 for a full description of RESET states of all
registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 11-4.
These devices have a MCLR noise filter in the MCLR
Reset path. The filter will detect and ignore small
pulses.
It should be noted that a WDT Reset does not drive
MCLR pin low.
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External
RESET
MCLR
WDT
Module
WDT
SLEEP
Time-out
Reset
VDD Rise
Detect
Power-on Reset
VDD
Brown-out
Reset
BOREN
S
OST/PWRT
OST
Chip_Reset
10-bit Ripple Counter
R
Q
OSC1
(1)
On-chip
RC OSC
PWRT
10-bit Ripple Counter
Enable PWRT
Enable OST
Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin.
 2003 Microchip Technology Inc.
DS30569B-page 91
PIC16F870/871
11.4
Power-on Reset (POR)
11.7
A Power-on Reset pulse is generated on-chip when
VDD rise is detected (in the range of 1.2V - 1.7V). To
take advantage of the POR, tie the MCLR pin directly
(or through a resistor) to VDD. This will eliminate
external RC components usually needed to create a
Power-on Reset. A maximum rise time for VDD is
specified. See Electrical Specifications for details.
When the device starts normal operation (exits the
RESET condition), device operating parameters (voltage, frequency, temperature,...) 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. Brown-out Reset may be used to meet the
start-up conditions. For additional information, refer to
Application Note, AN007, “Power-up Trouble Shooting”
(DS00007).
The configuration bit, BOREN, can enable or disable
the Brown-out Reset circuit. If VDD falls below VBOR
(parameter D005, about 4V) for longer than TBOR
(parameter #35, about 100 µS), the brown-out situation
will reset the device. If VDD falls below VBOR for less
than TBOR, a RESET may not occur.
Once the brown-out occurs, the device will remain in
Brown-out Reset until VDD rises above VBOR. The
Power-up Timer then keeps the device in RESET for
TPWRT (parameter #33, about 72 ms). If VDD should fall
below VBOR during TPWRT, the Brown-out Reset process will restart when VDD rises above VBOR with the
Power-up Timer Reset. The Power-up Timer is always
enabled when the Brown-out Reset circuit is enabled,
regardless of the state of the PWRT configuration bit.
11.8
11.5
Power-up Timer (PWRT)
The Power-up Timer provides a fixed 72 ms nominal
time-out on power-up only from the POR. The Powerup Timer operates on an internal RC oscillator. The
chip is kept in RESET as long as the PWRT is active.
The PWRT’s time delay allows VDD to rise to an
acceptable level. A configuration bit is provided to
enable/disable the PWRT.
The power-up time delay will vary from chip to chip due
to VDD, temperature and process variation. See DC
parameters for details (TPWRT, parameter #33).
11.6
Oscillator Start-up Timer (OST)
The Oscillator Start-up Timer (OST) provides a delay of
1024 oscillator cycles (from OSC1 input) after the
PWRT delay is over (if PWRT is enabled). This helps to
ensure 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.
Brown-out Reset (BOR)
Time-out Sequence
On power-up, the time-out sequence is as follows: The
PWRT delay starts (if enabled) when a POR Reset
occurs. Then OST starts counting 1024 oscillator
cycles when PWRT ends (LP, XT, HS). When the OST
ends, the device comes out of RESET.
If MCLR is kept low long enough, the time-outs will
expire. Bringing MCLR high will begin execution immediately. This is useful for testing purposes or to synchronize more than one PIC16F870/871 device operating in
parallel.
Table 11-5 shows the RESET conditions for the
STATUS, PCON and PC registers, while Table 11-6
shows the RESET conditions for all the registers.
11.9
Power Control/Status Register
(PCON)
The Power Control/Status Register, PCON, has up to
two bits depending upon the device.
Bit0 is Brown-out Reset Status bit, BOR. Bit BOR is
unknown on a Power-on Reset. It must then be set by
the user and checked on subsequent RESETS to see if
bit BOR cleared, indicating a BOR occurred. When the
Brown-out Reset is disabled, the state of the BOR bit is
unpredictable and is, therefore, not valid at any time.
Bit1 is POR (Power-on Reset Status bit). It is cleared on
a Power-on Reset and unaffected otherwise. The user
must set this bit following a Power-on Reset.
TABLE 11-3:
Oscillator
Configuration
XT, HS, LP
RC
DS30569B-page 92
TIME-OUT IN VARIOUS SITUATIONS
Power-up
Brown-out
Wake-up from SLEEP
1024 TOSC
72 ms + 1024 TOSC
1024 TOSC
—
72 ms
—
PWRTEN = 0
PWRTEN = 1
72 ms + 1024 TOSC
72 ms
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 11-4:
STATUS BITS AND THEIR SIGNIFICANCE
POR
BOR
TO
PD
0
x
1
1
Power-on Reset
0
x
0
x
Illegal, TO is set on POR
0
x
x
0
Illegal, PD is set on POR
1
0
1
1
Brown-out Reset
1
1
0
1
WDT Reset
1
1
0
0
WDT Wake-up
1
1
u
u
MCLR Reset during normal operation
1
1
0
MCLR Reset during SLEEP or interrupt wake-up from SLEEP
1
Legend:
x = don’t care, u = unchanged
TABLE 11-5:
RESET CONDITION FOR SPECIAL REGISTERS
Program
Counter
STATUS
Register
PCON
Register
Power-on Reset
000h
0001 1xxx
---- --0x
MCLR Reset during normal operation
000h
000u uuuu
---- --uu
MCLR Reset during SLEEP
000h
0001 0uuu
---- --uu
000h
0000 1uuu
---- --uu
PC + 1
uuu0 0uuu
---- --uu
Condition
WDT Reset
WDT Wake-up
Brown-out Reset
Interrupt wake-up from SLEEP
Legend:
Note 1:
000h
0001 1uuu
---- --u0
PC + 1(1)
uuu1 0uuu
---- --uu
u = unchanged, x = unknown, - = unimplemented bit, read as '0'
When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).
TABLE 11-6:
INITIALIZATION CONDITIONS FOR ALL REGISTERS
Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
Wake-up via WDT or
Interrupt
W
INDF
TMR0
PIC16F870 PIC16F871
PIC16F870 PIC16F871
PIC16F870 PIC16F871
xxxx xxxx
N/A
xxxx xxxx
uuuu uuuu
N/A
uuuu uuuu
uuuu uuuu
N/A
uuuu uuuu
PCL
PIC16F870 PIC16F871
0000h
0000h
PC + 1(2)
STATUS
FSR
PORTA
PORTB
PORTC
PORTD
PORTE
PCLATH
PIC16F870
PIC16F870
PIC16F870
PIC16F870
PIC16F870
PIC16F870
PIC16F870
PIC16F870
Register
PIC16F871
PIC16F871
PIC16F871
PIC16F871
PIC16F871
PIC16F871
PIC16F871
PIC16F871
0001
xxxx
--0x
xxxx
xxxx
xxxx
------0
1xxx
xxxx
0000
xxxx
xxxx
xxxx
-xxx
0000
000q
uuuu
--0u
uuuu
uuuu
uuuu
------0
quuu(3)
uuuu
0000
uuuu
uuuu
uuuu
-uuu
0000
uuuq
uuuu
--uu
uuuu
uuuu
uuuu
------u
quuu(3)
uuuu
uuuu
uuuu
uuuu
uuuu
-uuu
uuuu
INTCON
PIC16F870 PIC16F871
0000 000x
0000 000u
uuuu uuuu(1)
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition,
r = reserved, maintain clear
Note 1: One or more bits in INTCON, PIR1 and/or PIR2 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 11-5 for RESET value for specific condition.
 2003 Microchip Technology Inc.
DS30569B-page 93
PIC16F870/871
TABLE 11-6:
Register
PIR1
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
PIC16F871
r000 -000
r000 -000
ruuu -uuu(1)
PIC16F870 PIC16F871
0000 -000
0000 -000
uuuu -uuu(1)
Devices
PIC16F870
Wake-up via WDT or
Interrupt
PIC16F870 PIC16F871
---0 ------0 ------u ----(1)
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
--00 0000
--uu uuuu
--uu uuuu
PIC16F870 PIC16F871
0000 0000
0000 0000
uuuu uuuu
PIC16F870 PIC16F871
-000 0000
-000 0000
-uuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
--00 0000
--00 0000
--uu uuuu
PIC16F870 PIC16F871
0000 000x
0000 000x
uuuu uuuu
PIC16F870 PIC16F871
0000 0000
0000 0000
uuuu uuuu
PIC16F870 PIC16F871
0000 0000
0000 0000
uuuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
0000 00-0
0000 00-0
uuuu uu-u
PIC16F870 PIC16F871
1111 1111
1111 1111
uuuu uuuu
PIC16F870 PIC16F871
--11 1111
--11 1111
--uu uuuu
PIC16F870 PIC16F871
1111 1111
1111 1111
uuuu uuuu
PIC16F870 PIC16F871
1111 1111
1111 1111
uuuu uuuu
PIC16F870 PIC16F871
1111 1111
1111 1111
uuuu uuuu
PIC16F870 PIC16F871
0000 -111
0000 -111
uuuu -uuu
PIC16F870 PIC16F871
r000 -000
r000 -000
ruuu -uuu
PIC16F870 PIC16F871
0000 0000
0000 0000
uuuu uuuu
PIC16F870 PIC16F871
---0 ------0 ------u ---PIC16F870 PIC16F871
---- --qq
---- --uu
---- --uu
PIC16F870 PIC16F871
1111 1111
1111 1111
1111 1111
PIC16F870 PIC16F871
0000 -010
0000 -010
uuuu -uuu
PIC16F870 PIC16F871
0000 0000
0000 0000
uuuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
0--- 0000
0--- 0000
u--- uuuu
PIC16F870 PIC16F871
0--- 0000
0--- 0000
u--- uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
xxxx xxxx
uuuu uuuu
uuuu uuuu
PIC16F870 PIC16F871
x--- x000
u--- u000
u--- uuuu
PIC16F870 PIC16F871
---- ------- ------- ---u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition,
r = reserved, maintain clear
One or more bits in INTCON, PIR1 and/or PIR2 will be affected (to cause wake-up).
When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector
(0004h).
See Table 11-5 for RESET value for specific condition.
PIR2
TMR1L
TMR1H
T1CON
TMR2
T2CON
CCPR1L
CCPR1H
CCP1CON
RCSTA
TXREG
RCREG
ADRESH
ADCON0
OPTION_REG
TRISA
TRISB
TRISC
TRISD
TRISE
PIE1
PIE2
PCON
PR2
TXSTA
SPBRG
ADRESL
ADCON1
EEDATA
EEADR
EEDATH
EEADRH
EECON1
EECON2
Legend:
Note 1:
2:
3:
DS30569B-page 94
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 11-5:
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD)
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
FIGURE 11-6:
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
FIGURE 11-7:
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
 2003 Microchip Technology Inc.
DS30569B-page 95
PIC16F870/871
FIGURE 11-8:
SLOW RISE TIME (MCLR TIED TO VDD)
5V
VDD
1V
0V
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
11.10 Interrupts
The PIC16F870/871 family has up to 14 sources of
interrupt. The Interrupt Control register (INTCON)
records individual interrupt requests in flag bits. It also
has individual and global interrupt enable bits.
Note:
Individual interrupt flag bits are set,
regardless of the status of their
corresponding mask bit, or the GIE bit.
A global interrupt enable bit, GIE (INTCON<7>),
enables (if set) all unmasked interrupts, or disables (if
cleared) all interrupts. When bit GIE is enabled, and an
interrupt’s flag bit and mask bit are set, the interrupt will
vector immediately. Individual interrupts can be disabled through their corresponding enable bits in various registers. Individual interrupt bits are set,
regardless of the status of the GIE bit. The GIE bit is
cleared on RESET.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine as well as sets the GIE bit, which
re-enables interrupts.
The peripheral interrupt flags are contained in the special function registers, PIR1 and PIR2. The corresponding interrupt enable bits are contained in special
function registers, PIE1 and PIE2, and the peripheral
interrupt enable bit is contained in special function
register, INTCON.
When an interrupt is responded to, the GIE bit is
cleared to disable any further interrupt, the return
address is pushed onto 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 software before re-enabling interrupts to
avoid 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 event occurs. The latency
is the same for one or two-cycle instructions. Individual
interrupt flag bits are set, regardless of the status of
their corresponding mask bit, PEIE bit, or GIE bit.
The RB0/INT pin interrupt, the RB port change
interrupt, and the TMR0 overflow interrupt flags are
contained in the INTCON register.
DS30569B-page 96
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 11-9:
INTERRUPT LOGIC
EEIF
EEIE
PSPIF
PSPIE
ADIF
ADIE
Wake-up (If in SLEEP mode)
T0IF
T0IE
INTF
INTE
RCIF
RCIE
TXIF
TXIE
Interrupt to CPU
RBIF
RBIE
PEIE
CCP1IF
CCP1IE
GIE
TMR2IF
TMR2IE
TMR1IF
TMR1IE
The following table shows which devices have which interrupts.
Device
T0IF
INTF
RBIF
PIC18F870
Yes
Yes
Yes
—
Yes
Yes
Yes
Yes
PIC18F871
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
11.10.1
PSPIF
ADIF
INT INTERRUPT
External interrupt on the RB0/INT pin is edge triggered,
either rising, if bit INTEDG (OPTION_REG<6>) is set,
or falling, if the INTEDG bit is clear. When a valid edge
appears on the RB0/INT pin, flag bit INTF
(INTCON<1>) is set. This interrupt can be disabled by
clearing enable bit INTE (INTCON<4>). Flag bit INTF
must be cleared in software in the Interrupt Service
Routine before re-enabling this interrupt. The INT interrupt can wake-up the processor from SLEEP, if bit INTE
was set prior to going into SLEEP. The status of global
interrupt enable bit, GIE, decides whether or not the
processor branches to the interrupt vector following
wake-up. See Section 11.13 for details on SLEEP
mode.
 2003 Microchip Technology Inc.
RCIF
TXIF
11.10.2
CCP1IF
TMR2IF
TMR1IF
EEIF
Yes
Yes
Yes
Yes
Yes
Yes
TMR0 INTERRUPT
An overflow (FFh → 00h) in the TMR0 register will set
flag bit T0IF (INTCON<2>). The interrupt can be
enabled/disabled by setting/clearing enable bit T0IE
(INTCON<5>) (Section 5.0).
11.10.3
PORTB INTCON CHANGE
An input change on PORTB<7:4> sets flag bit RBIF
(INTCON<0>). The interrupt can be enabled/disabled
by setting/clearing enable bit RBIE (INTCON<4>)
(Section 4.2).
DS30569B-page 97
PIC16F870/871
11.11 Context Saving During Interrupts
During an interrupt, only the return PC value is saved
on the stack. Typically, users may wish to save key registers during an interrupt, (i.e., W register and STATUS
register). This will have to be implemented in software.
For the PIC16F870/871 devices, the register W_TEMP
must be defined in both banks 0 and 1 and must be
defined at the same offset from the bank base address
(i.e., If W_TEMP is defined at 0x20 in bank 0, it must
also be defined at 0xA0 in bank 1). The registers,
PCLATH_TEMP and STATUS_TEMP, are only defined
in bank 0.
EXAMPLE 11-1:
Since the upper 16 bytes of each bank are common in
the PIC16F870/871 devices, temporary holding registers W_TEMP, STATUS_TEMP, and PCLATH_TEMP
should be placed in here. These 16 locations don’t
require banking and therefore, make it easier for context save and restore. The same code shown in
Example 11-1 can be used.
SAVING STATUS, W, AND PCLATH REGISTERS IN RAM
MOVWF
SWAPF
CLRF
MOVWF
MOVF
MOVWF
CLRF
:
:(ISR)
:
MOVF
MOVWF
SWAPF
W_TEMP
STATUS,W
STATUS
STATUS_TEMP
PCLATH, W
PCLATH_TEMP
PCLATH
MOVWF
SWAPF
SWAPF
STATUS
W_TEMP,F
W_TEMP,W
;Copy
;Swap
;bank
;Save
;Only
;Save
;Page
W to TEMP register
status to be saved into W
0, regardless of current bank, Clears IRP,RP1,RP0
status to bank zero STATUS_TEMP register
required if using pages 1, 2 and/or 3
PCLATH into W
zero, regardless of current page
;(Insert user code here)
PCLATH_TEMP, W
PCLATH
STATUS_TEMP,W
DS30569B-page 98
;Restore PCLATH
;Move W into PCLATH
;Swap STATUS_TEMP register into W
;(sets bank to original state)
;Move W into STATUS register
;Swap W_TEMP
;Swap W_TEMP into W
 2003 Microchip Technology Inc.
PIC16F870/871
11.12 Watchdog Timer (WDT)
WDT time-out period values may be found in the Electrical Specifications section under parameter #31. Values for the WDT prescaler (actually a postscaler, but
shared with the Timer0 prescaler) may be assigned
using the OPTION_REG register.
The Watchdog Timer is a free running on-chip RC oscillator which does not require any external components.
This RC oscillator is separate from the RC oscillator of
the OSC1/CLKI pin. That means that the WDT will run,
even if the clock on the OSC1/CLKI and OSC2/CLKO
pins of the device has been stopped, for example, by
execution of a SLEEP instruction.
Note 1: The CLRWDT and SLEEP instructions
clear the WDT and the postscaler, if
assigned to the WDT, and prevent it from
timing out and generating a device
RESET condition.
During normal operation, a WDT time-out generates a
device RESET (Watchdog Timer Reset). If the device is
in SLEEP mode, a WDT time-out causes the device to
wake-up and continue with normal operation
(Watchdog Timer Wake-up). The TO bit in the STATUS
register will be cleared upon a Watchdog Timer
time-out.
2: When a CLRWDT instruction is executed
and the prescaler is assigned to the WDT,
the prescaler count will be cleared, but
the prescaler assignment is not changed.
The WDT can be permanently disabled by clearing
configuration bit WDTEN (Section 11.1).
FIGURE 11-10:
WATCHDOG TIMER BLOCK DIAGRAM
From TMR0 Clock Source
(Figure 5-1)
0
WDT Timer
1
Postscaler
M
U
X
8
8 - to - 1 MUX
PS2:PS0
PSA
WDT
Enable Bit
To TMR0 (Figure 5-1)
0
1
MUX
PSA
WDT
Time-out
Note:
PSA and PS2:PS0 are bits in the OPTION_REG register.
TABLE 11-7:
Address
2007h
81h,181h
Legend:
Note 1:
SUMMARY OF WATCHDOG TIMER REGISTERS
Name
Config. bits
OPTION_REG
Bit 7
Bit 6
Bit 5
Bit 4
(1)
BOREN(1)
CP1
CP0
RBPU
INTEDG
T0CS
T0SE
Bit 3
Bit 2
PWRTEN(1) WDTEN
PSA
PS2
Bit 1
Bit 0
FOSC1
FOSC0
PS1
PS0
Shaded cells are not used by the Watchdog Timer.
See Register 11-1 for operation of these bits.
 2003 Microchip Technology Inc.
DS30569B-page 99
PIC16F870/871
11.13 Power-down Mode (SLEEP)
Power-down mode is entered by executing a SLEEP
instruction.
If enabled, the Watchdog Timer will be cleared but
keeps running, the PD bit (STATUS<3>) is cleared, the
TO (STATUS<4>) bit is set, and the oscillator driver is
turned off. The I/O ports maintain the status they had
before the SLEEP instruction was executed (driving
high, low, or hi-impedance).
For lowest current consumption in this mode, place all
I/O pins at either VDD or VSS, ensure no external circuitry is drawing current from the I/O pin, power-down
the A/D and disable external clocks. Pull all I/O pins
that are hi-impedance inputs, high or low externally, to
avoid switching currents caused by floating inputs. The
T0CKI input should also be at VDD or VSS for lowest
current consumption. The contribution from on-chip
pull-ups on PORTB should also be considered.
The MCLR pin must be at a logic high level (VIHMC).
11.13.1
WAKE-UP FROM SLEEP
The device can wake-up from SLEEP through one of
the following events:
1.
2.
3.
External RESET input on MCLR pin.
Watchdog Timer Wake-up (if WDT was
enabled).
Interrupt from INT pin, RB port change or
peripheral interrupt.
External MCLR Reset will cause a device RESET. All
other events are considered a continuation of program
execution and cause a “wake-up”. The TO and PD bits
in the STATUS register can be used to determine the
cause of device RESET. The PD bit, which is set on
power-up, is cleared when SLEEP is invoked. The TO
bit is cleared if a WDT time-out occurred and caused
wake-up.
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is pre-fetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). 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 instruction after
the SLEEP instruction and then branches to the interrupt address (0004h). In cases where the execution of
the instruction following SLEEP is not desirable, the
user should have a NOP after the SLEEP instruction.
11.13.2
WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
SLEEP instruction, the SLEEP instruction will complete as a NOP. Therefore, the WDT and WDT
postscaler will not be cleared, the TO bit will not
be set and PD bits will not be cleared.
• If the interrupt occurs during or after the
execution of a SLEEP instruction, the device will
immediately wake-up from SLEEP. The SLEEP
instruction will be completely executed before the
wake-up. Therefore, the WDT and WDT
postscaler will be cleared, the TO bit will be set
and the PD bit will be cleared.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT
instruction should be executed before a SLEEP
instruction.
The following peripheral interrupts can wake the device
from SLEEP:
1.
2.
3.
4.
5.
6.
7.
8.
9.
PSP read or write (PIC16F874/877 only).
TMR1 interrupt. Timer1 must be operating as an
asynchronous counter.
CCP Capture mode interrupt.
Special event trigger (Timer1 in Asynchronous
mode using an external clock).
SSP (START/STOP) bit detect interrupt.
SSP transmit or receive in Slave mode
(SPI/I2C).
USART RX or TX (Synchronous Slave mode).
A/D conversion (when A/D clock source is RC).
EEPROM write operation completion
Other peripherals cannot generate interrupts, since
during SLEEP, no on-chip clocks are present.
DS30569B-page 100
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 11-11:
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
TOST(2)
CLKO(4)
INT pin
INTF Flag
(INTCON<1>)
Interrupt Latency(2)
GIE bit
(INTCON<7>)
Processor in
SLEEP
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
Note 1:
2:
3:
4:
PC
PC+1
Inst(PC) = SLEEP
Inst(PC - 1)
PC+2
PC+2
Inst(PC + 1)
Inst(PC + 2)
SLEEP
Inst(PC + 1)
PC + 2
Dummy cycle
0004h
0005h
Inst(0004h)
Inst(0005h)
Dummy cycle
Inst(0004h)
XT, HS or LP Oscillator mode assumed.
TOST = 1024 TOSC (drawing not to scale). This delay will not be there for RC Osc mode.
GIE = 1 assumed. In this case, after wake- up, the processor jumps to the interrupt routine. If GIE = 0, execution will continue in-line.
CLKO is not available in these Osc modes, but shown here for timing reference.
11.14 In-Circuit Debugger
When the DEBUG bit in the configuration word is programmed to a '0', the In-Circuit Debugger functionality
is enabled. This function allows simple debugging functions when used with MPLAB® ICD. When the microcontroller has this feature enabled, some of the
resources are not available for general use. Table 11-8
shows which features are consumed by the
background debugger.
TABLE 11-8:
DEBUGGER RESOURCES
I/O pins
RB6, RB7
Stack
1 level
Program Memory
Address 0000h must be NOP
11.15 Program Verification/Code
Protection
If the code protection bit(s) have not been programmed, the on-chip program memory can be read
out for verification purposes.
11.16 ID Locations
Four memory 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. It is recommended that only the 4 Least Significant bits of the ID
location are used.
Last 100h words
Data Memory
0x070 (0x0F0, 0x170, 0x1F0)
0x1EB - 0x1EF
To use the In-Circuit Debugger function of the microcontroller, the design must implement In-Circuit Serial
Programming connections to MCLR/VPP, VDD, GND,
RB7 and RB6. This will interface to the In-Circuit
Debugger module available from Microchip, or one of
the third party development tool companies.
 2003 Microchip Technology Inc.
DS30569B-page 101
PIC16F870/871
11.17
In-Circuit Serial Programming
PIC16F870/871 microcontrollers can be serially programmed while in the end application circuit. This is
simply done with two lines for 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.
When using ICSP, the part must be supplied at 4.5V to
5.5V, if a bulk erase will be executed. This includes
reprogramming of the code protect, both from an onstate to off-state. For all other cases of ICSP, the part
may be programmed at the normal operating voltages.
This means calibration values, unique user IDs, or user
code can be reprogrammed or added.
For complete details of serial programming, please
refer to the EEPROM Memory Programming
Specification for the PIC16F87X (DS39025).
11.18 Low Voltage ICSP Programming
The LVP bit of the configuration word enables low voltage ICSP programming. This mode allows the microcontroller to be programmed via ICSP, using a VDD
source in the operating voltage range. This only means
that VPP does not have to be brought to VIHH, but can
instead be left at the normal operating voltage. In this
mode, the RB3/PGM pin is dedicated to the programming function and ceases to be a general purpose I/O
pin. During programming, VDD is applied to the MCLR
pin. To enter Programming mode, VDD must be applied
to the RB3/PGM pin, provided the LVP bit is set. The
LVP bit defaults to on (‘1’) from the factory.
Note 1: The High Voltage Programming mode is
always available, regardless of the state
of the LVP bit, by applying VIHH to the
MCLR pin.
2: While in Low Voltage ICSP mode, the
RB3 pin can no longer be used as a
general purpose I/O pin.
3: When using low voltage ICSP programming (LVP) and the pull-ups on PORTB
are enabled, bit 3 in the TRISB register
must be cleared to disable the pull-up on
RB3 and ensure the proper operation of
the device.
4: RB3 should not be allowed to float if LVP
is enabled. An external pull-down device
should be used to default the device to
normal Operating mode. If RB3 floats
high, the PIC16F870/871 devices will
enter Programming mode.
5: LVP mode is enabled by default on all
devices shipped from Microchip. It can be
disabled by clearing the LVP bit in the
CONFIG register.
6: Disabling LVP will provide maximum
compatibility to other PIC16CXXX
devices.
If Low Voltage Programming mode is not used, the LVP
bit can be programmed to a '0' and RB3/PGM becomes
a digital I/O pin. However, the LVP bit may only be programmed when programming is entered with VIHH on
MCLR. The LVP bit can only be charged when using
high voltage on MCLR.
It should be noted, that once the LVP bit is programmed
to 0, only the High Voltage Programming mode is available and only High Voltage Programming mode can be
used to program the device.
When using low voltage ICSP, the part must be supplied
at 4.5V to 5.5V, if a bulk erase will be executed. This
includes reprogramming of the code protect bits from an
on-state to off-state. For all other cases of low voltage
ICSP, the part may be programmed at the normal operating voltage. This means calibration values, unique
user IDs, or user code can be reprogrammed or added.
DS30569B-page 102
 2003 Microchip Technology Inc.
PIC16F870/871
12.0
INSTRUCTION SET SUMMARY
Each PIC16F870/871 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
PIC16F870/871 instruction set summary in Table 12-2
lists byte-oriented, bit-oriented, and literal and control operations. Table 12-1 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 affected
by the operation, while 'f' represents the address 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 12-1:
OPCODE FIELD
DESCRIPTIONS
Field
Description
f
Register file address (0x00 to 0x7F)
W
Working register (accumulator)
b
Bit address within an 8-bit file register
k
Literal field, constant data or label
x
Don'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.
d
Destination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1.
PC
Program Counter
TO
Time-out bit
PD
Power-down bit
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 12-2 lists the instructions recognized by the
MPASMTM assembler.
Figure 12-1 shows the general formats that the
instructions can have.
Note:
To maintain upward compatibility with
future PIC16F870/871 products, do not
use the OPTION and TRIS instructions.
All examples use the following format to represent a
hexadecimal number:
0xhh
where h signifies a hexadecimal digit.
FIGURE 12-1:
GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
13
8 7 6
OPCODE
d
f (FILE #)
0
d = 0 for destination W
d = 1 for destination f
f = 7-bit file register address
Bit-oriented file register operations
13
10 9
7 6
OPCODE
b (BIT #)
0
f (FILE #)
b = 3-bit bit address
f = 7-bit file register address
Literal and control operations
General
13
8
7
OPCODE
0
k (literal)
k = 8-bit immediate value
CALL and GOTO instructions only
13
11
OPCODE
10
0
k (literal)
k = 11-bit immediate value
A description of each instruction is available in the
PICmicro™ Mid-Range MCU Family Reference Manual
(DS33023).
 2003 Microchip Technology Inc.
DS30569B-page 103
PIC16F870/871
TABLE 12-2:
PIC16F870/871 INSTRUCTION SET
Mnemonic,
Operands
14-Bit Opcode
Description
Cycles
MSb
LSb
Status
Affected
Notes
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
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
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
0xxx
dfff
dfff
dfff
dfff
dfff
dfff
dfff
lfff
0xx0
dfff
dfff
dfff
dfff
dfff
ffff
ffff
ffff
xxxx
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
0000
ffff
ffff
ffff
ffff
ffff
00bb
01bb
10bb
11bb
bfff
bfff
bfff
bfff
ffff
ffff
ffff
ffff
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
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
1
1
1 (2)
1 (2)
01
01
01
01
1,2
1,2
3
3
LITERAL AND CONTROL OPERATIONS
ADDLW
ANDLW
CALL
CLRWDT
GOTO
IORLW
MOVLW
RETFIE
RETLW
RETURN
SLEEP
SUBLW
XORLW
Note 1:
2:
3:
Note:
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
C,DC,Z
Z
TO,PD
Z
TO,PD
C,DC,Z
Z
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'.
If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if
assigned to the Timer0 module.
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.
Additional information on the mid-range instruction set is available in the PICmicro™ Mid-Range MCU
Family Reference Manual (DS33023).
DS30569B-page 104
 2003 Microchip Technology Inc.
PIC16F870/871
12.1
Instruction Descriptions
ADDLW
Add Literal and W
BCF
Bit Clear f
Syntax:
[ label ] ADDLW
Syntax:
[ label ] BCF
Operands:
0 ≤ k ≤ 255
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
(W) + k → (W)
Status Affected:
C, DC, Z
Operation:
0 → (f<b>)
Description:
The contents of the W register
are added to the eight-bit literal 'k'
and the result is placed in the W
register.
Status Affected:
None
Description:
Bit 'b' in register 'f' is cleared.
ADDWF
Add W and f
BSF
Bit Set f
Syntax:
[ label ] ADDWF
Syntax:
[ label ] BSF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
(W) + (f) → (destination)
Operation:
1 → (f<b>)
Status Affected:
C, DC, Z
Status Affected:
None
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'.
Description:
Bit 'b' in register 'f' is set.
ANDLW
AND Literal with W
BTFSS
Bit Test f, Skip if Set
Syntax:
[ label ] ANDLW
Syntax:
[ label ] BTFSS f,b
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
(W) .AND. (k) → (W)
0 ≤ f ≤ 127
0≤b<7
Status Affected:
Z
Operation:
skip if (f<b>) = 1
Description:
The contents of W register are
AND’ed with the eight-bit literal
'k'. The result is placed in the W
register.
Status Affected:
None
Description:
If bit 'b' in register 'f' is '0', the next
instruction is executed.
If bit 'b' is '1', then the next instruction is discarded and a NOP is
executed instead, making this a
2 TCY instruction.
BTFSC
Bit Test, Skip if Clear
Syntax:
[ label ] BTFSC f,b
k
f,d
k
f,b
f,b
ANDWF
AND W with f
Syntax:
[ label ] ANDWF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
(W) .AND. (f) → (destination)
Operation:
skip if (f<b>) = 0
Status Affected:
Z
Status Affected:
None
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'.
Description:
If bit 'b' in register 'f' is '1', the next
instruction is executed.
If bit 'b', in register 'f', is '0', the
next instruction is discarded, and
a NOP is executed instead, making
this a 2 TCY instruction.
 2003 Microchip Technology Inc.
f,d
DS30569B-page 105
PIC16F870/871
CALL
Call Subroutine
CLRWDT
Clear Watchdog Timer
Syntax:
[ label ] CALL k
Syntax:
[ label ] CLRWDT
Operands:
0 ≤ k ≤ 2047
Operands:
None
Operation:
(PC)+ 1→ TOS,
k → PC<10:0>,
(PCLATH<4:3>) → PC<12:11>
Operation:
Status Affected:
None
00h → WDT
0 → WDT prescaler,
1 → TO
1 → PD
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.
Status Affected:
TO, PD
Description:
CLRWDT instruction resets the
Watchdog Timer. It also resets
the prescaler of the WDT. Status
bits TO and PD are set.
Clear f
COMF
Complement f
CLRF
Syntax:
[ label ] CLRF
Syntax:
[ label ] COMF
Operands:
0 ≤ f ≤ 127
Operands:
Operation:
00h → (f)
1→Z
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) → (destination)
Status Affected:
Z
Status Affected:
Z
Description:
The contents of register 'f' are
cleared and the Z bit is set.
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'.
CLRW
Clear W
DECF
Decrement f
Syntax:
[ label ] CLRW
Syntax:
[ label ] DECF f,d
Operands:
None
Operands:
Operation:
00h → (W)
1→Z
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) - 1 → (destination)
Status Affected:
Z
Status Affected:
Z
Description:
W register is cleared. Zero bit (Z)
is set.
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'.
DS30569B-page 106
f
f,d
 2003 Microchip Technology Inc.
PIC16F870/871
DECFSZ
Decrement f, Skip if 0
INCFSZ
Increment f, Skip if 0
Syntax:
[ label ] DECFSZ f,d
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) - 1 → (destination);
skip if result = 0
Operation:
(f) + 1 → (destination),
skip if result = 0
Status Affected:
None
Status Affected:
None
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 1, the next instruction is executed. If the result is 0,
then a NOP is executed instead
making it a 2 TCY instruction.
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 1, the next instruction is executed. If the result is 0,
a NOP is executed instead, making
it a 2 TCY instruction.
GOTO
Unconditional Branch
IORLW
Inclusive OR Literal with W
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 2047
Operands:
0 ≤ k ≤ 255
Operation:
k → PC<10:0>
PCLATH<4:3> → PC<12:11>
Operation:
(W) .OR. k → (W)
Status Affected:
Z
Status Affected:
None
Description:
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.
The contents of the W register are
OR’ed with the eight bit literal 'k'.
The result is placed in the W
register.
INCF
Increment f
IORWF
Inclusive OR W with f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) + 1 → (destination)
Operation:
(W) .OR. (f) → (destination)
Status Affected:
Z
Status Affected:
Z
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'.
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'.
GOTO k
INCF f,d
 2003 Microchip Technology Inc.
INCFSZ f,d
IORLW k
IORWF
f,d
DS30569B-page 107
PIC16F870/871
MOVF
Move f
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
No operation
Operation:
(f) → (destination)
Status Affected:
None
Status Affected:
Z
Description:
No operation.
Description:
The contents of register f are
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.
MOVLW
Move Literal to W
RETFIE
Return from Interrupt
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 255
Operands:
None
Operation:
k → (W)
Operation:
TOS → PC,
1 → GIE
MOVF f,d
MOVLW k
NOP
No Operation
Syntax:
[ label ]
Operands:
None
NOP
RETFIE
Status Affected:
None
Description:
The eight-bit literal 'k' is loaded
into W register. The don’t cares
will assemble as 0’s.
Status Affected:
None
MOVWF
Move W to f
RETLW
Return with Literal in W
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
Operands:
0 ≤ k ≤ 255
Operation:
(W) → (f)
Operation:
Status Affected:
None
k → (W);
TOS → PC
Description:
Move data from W register to
register 'f'.
Status Affected:
None
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.
DS30569B-page 108
MOVWF
f
RETLW k
 2003 Microchip Technology Inc.
PIC16F870/871
RLF
Rotate Left f through Carry
SLEEP
Syntax:
[ label ] RLF
Syntax:
[ label ] SLEEP
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
None
Operation:
Operation:
See description below
Status Affected:
C
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'.
00h → WDT,
0 → WDT prescaler,
1 → TO,
0 → PD
Status Affected:
TO, PD
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.
C
f,d
Register f
RETURN
Return from Subroutine
SUBLW
Subtract W from Literal
Syntax:
[ label ]
Syntax:
[ label ] SUBLW k
Operands:
None
Operands:
0 ≤ k ≤ 255
Operation:
TOS → PC
Operation:
k - (W) → (W)
Status Affected:
None
Status Affected: C, DC, Z
Description:
Return from subroutine. The stack
is POPed and the top of the stack
(TOS) is loaded into the program
counter. This is a two-cycle
instruction.
Description:
The W register is subtracted (2’s
complement method) from the
eight-bit literal 'k'. The result is
placed in the W register.
RRF
Rotate Right f through Carry
SUBWF
Subtract W from f
Syntax:
[ label ]
Syntax:
[ label ] SUBWF f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
See description below
Operation:
(f) - (W) → (destination)
Status Affected:
C
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'.
Status
Affected:
C, DC, Z
Description:
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'.
RETURN
RRF f,d
C
 2003 Microchip Technology Inc.
Register f
DS30569B-page 109
PIC16F870/871
SWAPF
Swap Nibbles in f
XORWF
Exclusive OR W with f
Syntax:
[ label ] SWAPF f,d
Syntax:
[ label ] XORWF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f<3:0>) → (destination<7:4>),
(f<7:4>) → (destination<3:0>)
Operation:
(W) .XOR. (f) → (destination)
Status Affected:
Z
Status Affected:
None
Description:
Description:
The upper and lower nibbles of
register 'f' are exchanged. If 'd' is
0, the result is placed in the W
register. If 'd' is 1, the result is
placed in register 'f'.
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'.
XORLW
Exclusive OR Literal with W
Syntax:
[ label ] XORLW k
Operands:
0 ≤ k ≤ 255
Operation:
(W) .XOR. k → (W)
Status Affected:
Z
Description:
The contents of the W register
are XOR’ed with the eight-bit
literal 'k'. The result is placed in
the W register.
DS30569B-page 110
f,d
 2003 Microchip Technology Inc.
PIC16F870/871
13.0
DEVELOPMENT SUPPORT
The PICmicro® microcontrollers are supported with a
full range of hardware and software development tools:
• Integrated Development Environment
- MPLAB® IDE Software
• Assemblers/Compilers/Linkers
- MPASMTM Assembler
- MPLAB C17 and MPLAB C18 C Compilers
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
- MPLAB C30 C Compiler
- MPLAB ASM30 Assembler/Linker/Library
• Simulators
- MPLAB SIM Software Simulator
- MPLAB dsPIC30 Software Simulator
• Emulators
- MPLAB ICE 2000 In-Circuit Emulator
- MPLAB ICE 4000 In-Circuit Emulator
• In-Circuit Debugger
- MPLAB ICD 2
• Device Programmers
- PRO MATE® II Universal Device Programmer
- PICSTART® Plus Development Programmer
• Low Cost Demonstration Boards
- PICDEMTM 1 Demonstration Board
- PICDEM.netTM Demonstration Board
- PICDEM 2 Plus Demonstration Board
- PICDEM 3 Demonstration Board
- PICDEM 4 Demonstration Board
- PICDEM 17 Demonstration Board
- PICDEM 18R Demonstration Board
- PICDEM LIN Demonstration Board
- PICDEM USB Demonstration Board
• Evaluation Kits
- KEELOQ®
- PICDEM MSC
- microID®
- CAN
- PowerSmart®
- Analog
13.1
MPLAB Integrated Development
Environment Software
The MPLAB IDE software brings an ease of software
development previously unseen in the 8/16-bit microcontroller market. The MPLAB IDE is a Windows®
based application that contains:
• An interface to debugging tools
- simulator
- programmer (sold separately)
- emulator (sold separately)
- in-circuit debugger (sold separately)
• A full-featured editor with color coded context
• A multiple project manager
• Customizable data windows with direct edit of
contents
• High level source code debugging
• Mouse over variable inspection
• Extensive on-line help
The MPLAB IDE allows you to:
• Edit your source files (either assembly or C)
• One touch assemble (or compile) and download
to PICmicro emulator and simulator tools
(automatically updates all project information)
• Debug using:
- source files (assembly or C)
- absolute listing file (mixed assembly and C)
- machine code
MPLAB IDE supports multiple debugging tools in a
single development paradigm, from the cost effective
simulators, through low cost in-circuit debuggers, to
full-featured emulators. This eliminates the learning
curve when upgrading to tools with increasing flexibility
and power.
13.2
MPASM Assembler
The MPASM assembler is a full-featured, universal
macro assembler for all PICmicro MCUs.
The MPASM assembler generates relocatable object
files for the MPLINK object linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol reference, absolute LST files that contain source lines and
generated machine code and COFF files for
debugging.
The MPASM assembler features include:
• Integration into MPLAB IDE projects
• User defined macros to streamline assembly code
• Conditional assembly for multi-purpose source
files
• Directives that allow complete control over the
assembly process
 2003 Microchip Technology Inc.
DS30569B-page 111
PIC16F870/871
13.3
MPLAB C17 and MPLAB C18
C Compilers
The MPLAB C17 and MPLAB C18 Code Development
Systems are complete ANSI C compilers for
Microchip’s PIC17CXXX and PIC18CXXX family of
microcontrollers. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use not found with other compilers.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
13.4
MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK object linker combines relocatable
objects created by the MPASM assembler and the
MPLAB C17 and MPLAB C18 C compilers. It can link
relocatable objects from pre-compiled libraries, using
directives from a linker script.
The MPLIB object librarian manages the creation and
modification of library files of pre-compiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:
• Efficient linking of single libraries instead of many
smaller files
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
13.5
MPLAB C30 C Compiler
The MPLAB C30 C compiler is a full-featured, ANSI
compliant, optimizing compiler that translates standard
ANSI C programs into dsPIC30F assembly language
source. The compiler also supports many commandline options and language extensions to take full
advantage of the dsPIC30F device hardware capabilities, and afford fine control of the compiler code
generator.
MPLAB C30 is distributed with a complete ANSI C
standard library. All library functions have been validated and conform to the ANSI C library standard. The
library includes functions for string manipulation,
dynamic memory allocation, data conversion, timekeeping, and math functions (trigonometric, exponential and hyperbolic). The compiler provides symbolic
information for high level source debugging with the
MPLAB IDE.
DS30569B-page 112
13.6
MPLAB ASM30 Assembler, Linker,
and Librarian
MPLAB ASM30 assembler produces relocatable
machine code from symbolic assembly language for
dsPIC30F devices. MPLAB C30 compiler uses the
assembler to produce it’s object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:
•
•
•
•
•
•
Support for the entire dsPIC30F instruction set
Support for fixed-point and floating-point data
Command line interface
Rich directive set
Flexible macro language
MPLAB IDE compatibility
13.7
MPLAB SIM Software Simulator
The MPLAB SIM software simulator allows code development in a PC hosted environment by simulating the
PICmicro series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any pin. The execution can be performed in Single-Step, Execute Until
Break, or Trace mode.
The MPLAB SIM simulator fully supports symbolic
debugging using the MPLAB C17 and MPLAB C18
C Compilers, as well as the MPASM assembler. The
software simulator offers the flexibility to develop and
debug code outside of the laboratory environment,
making it an excellent, economical software
development tool.
13.8
MPLAB SIM30 Software Simulator
The MPLAB SIM30 software simulator allows code
development in a PC hosted environment by simulating
the dsPIC30F series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any of the pins.
The MPLAB SIM30 simulator fully supports symbolic
debugging using the MPLAB C30 C Compiler and
MPLAB ASM30 assembler. The simulator runs in either
a Command Line mode for automated tasks, or from
MPLAB IDE. This high speed simulator is designed to
debug, analyze and optimize time intensive DSP
routines.
 2003 Microchip Technology Inc.
PIC16F870/871
13.9
MPLAB ICE 2000
High Performance Universal
In-Circuit Emulator
The MPLAB ICE 2000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for
PICmicro microcontrollers. Software control of the
MPLAB ICE 2000 in-circuit emulator is advanced by
the MPLAB Integrated Development Environment,
which allows editing, building, downloading and source
debugging from a single environment.
The MPLAB ICE 2000 is a full-featured emulator system with enhanced trace, trigger and data monitoring
features. Interchangeable processor modules allow the
system to be easily reconfigured for emulation of different processors. The universal architecture of the
MPLAB ICE in-circuit emulator allows expansion to
support new PICmicro microcontrollers.
The MPLAB ICE 2000 in-circuit emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft® Windows 32-bit operating system were
chosen to best make these features available in a
simple, unified application.
13.10 MPLAB ICE 4000
High Performance Universal
In-Circuit Emulator
The MPLAB ICE 4000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for highend PICmicro microcontrollers. Software control of the
MPLAB ICE in-circuit emulator is provided by the
MPLAB Integrated Development Environment, which
allows editing, building, downloading and source
debugging from a single environment.
The MPLAB ICD 4000 is a premium emulator system,
providing the features of MPLAB ICE 2000, but with
increased emulation memory and high speed performance for dsPIC30F and PIC18XXXX devices. Its
advanced emulator features include complex triggering
and timing, up to 2 Mb of emulation memory, and the
ability to view variables in real-time.
13.11 MPLAB ICD 2 In-Circuit Debugger
Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a
powerful, low cost, run-time development tool,
connecting to the host PC via an RS-232 or high speed
USB interface. This tool is based on the FLASH
PICmicro MCUs and can be used to develop for these
and other PICmicro microcontrollers. The MPLAB
ICD 2 utilizes the in-circuit debugging capability built
into the FLASH devices. This feature, along with
Microchip’s In-Circuit Serial ProgrammingTM (ICSPTM)
protocol, offers cost effective in-circuit FLASH debugging from the graphical user interface of the MPLAB
Integrated Development Environment. This enables a
designer to develop and debug source code by setting
breakpoints, single-stepping and watching variables,
CPU status and peripheral registers. Running at full
speed enables testing hardware and applications in
real-time. MPLAB ICD 2 also serves as a development
programmer for selected PICmicro devices.
13.12 PRO MATE II Universal Device
Programmer
The PRO MATE II is a universal, CE compliant device
programmer with programmable voltage verification at
VDDMIN and VDDMAX for maximum reliability. It features
an LCD display for instructions and error messages
and a modular detachable socket assembly to support
various package types. In Stand-Alone mode, the
PRO MATE II device programmer can read, verify, and
program PICmicro devices without a PC connection. It
can also set code protection in this mode.
13.13 PICSTART Plus Development
Programmer
The PICSTART Plus development programmer is an
easy-to-use, low cost, prototype programmer. It connects to the PC via a COM (RS-232) port. MPLAB
Integrated Development Environment software makes
using the programmer simple and efficient. The
PICSTART Plus development programmer supports
most PICmicro devices up to 40 pins. Larger pin count
devices, such as the PIC16C92X and PIC17C76X,
may be supported with an adapter socket. The
PICSTART Plus development programmer is CE
compliant.
The MPLAB ICE 4000 in-circuit emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft Windows 32-bit operating system were chosen to best make these features available in a simple,
unified application.
 2003 Microchip Technology Inc.
DS30569B-page 113
PIC16F870/871
13.14 PICDEM 1 PICmicro
Demonstration Board
13.17 PICDEM 3 PIC16C92X
Demonstration Board
The PICDEM 1 demonstration board demonstrates the
capabilities of the 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 sample microcontrollers
provided with the PICDEM 1 demonstration board can
be programmed with a PRO MATE II device programmer, or a PICSTART Plus development programmer.
The PICDEM 1 demonstration board can be connected
to the MPLAB ICE in-circuit emulator for testing. A prototype area extends the circuitry for additional application components. Features include an RS-232
interface, a potentiometer for simulated analog input,
push button switches and eight LEDs.
The PICDEM 3 demonstration board supports the
PIC16C923 and PIC16C924 in the PLCC package. All
the necessary hardware and software is included to run
the demonstration programs.
13.15 PICDEM.net Internet/Ethernet
Demonstration Board
The PICDEM.net demonstration board is an Internet/
Ethernet demonstration board using the PIC18F452
microcontroller and TCP/IP firmware. The board
supports any 40-pin DIP device that conforms to the
standard pinout used by the PIC16F877 or
PIC18C452. This kit features a user friendly TCP/IP
stack, web server with HTML, a 24L256 Serial
EEPROM for Xmodem download to web pages into
Serial EEPROM, ICSP/MPLAB ICD 2 interface connector, an Ethernet interface, RS-232 interface, and a
16 x 2 LCD display. Also included is the book and
CD-ROM “TCP/IP Lean, Web Servers for Embedded
Systems,” by Jeremy Bentham
13.16 PICDEM 2 Plus
Demonstration Board
The PICDEM 2 Plus demonstration board supports
many 18-, 28-, and 40-pin microcontrollers, including
PIC16F87X and PIC18FXX2 devices. All the necessary hardware and software is included to run the demonstration programs. The sample microcontrollers
provided with the PICDEM 2 demonstration board can
be programmed with a PRO MATE II device programmer, PICSTART Plus development programmer, or
MPLAB ICD 2 with a Universal Programmer Adapter.
The MPLAB ICD 2 and MPLAB ICE in-circuit emulators
may also be used with the PICDEM 2 demonstration
board to test firmware. A prototype area extends the
circuitry for additional application components. Some
of the features include an RS-232 interface, a 2 x 16
LCD display, a piezo speaker, an on-board temperature
sensor, four LEDs, and sample PIC18F452 and
PIC16F877 FLASH microcontrollers.
DS30569B-page 114
13.18 PICDEM 4 8/14/18-Pin
Demonstration Board
The PICDEM 4 can be used to demonstrate the capabilities of the 8-, 14-, and 18-pin PIC16XXXX and
PIC18XXXX MCUs, including the PIC16F818/819,
PIC16F87/88, PIC16F62XA and the PIC18F1320 family of microcontrollers. PICDEM 4 is intended to showcase the many features of these low pin count parts,
including LIN and Motor Control using ECCP. Special
provisions are made for low power operation with the
supercapacitor circuit, and jumpers allow on-board
hardware to be disabled to eliminate current draw in
this mode. Included on the demo board are provisions
for Crystal, RC or Canned Oscillator modes, a five volt
regulator for use with a nine volt wall adapter or battery,
DB-9 RS-232 interface, ICD connector for programming via ICSP and development with MPLAB ICD 2,
2x16 liquid crystal display, PCB footprints for H-Bridge
motor driver, LIN transceiver and EEPROM. Also
included are: header for expansion, eight LEDs, four
potentiometers, three push buttons and a prototyping
area. Included with the kit is a PIC16F627A and a
PIC18F1320. Tutorial firmware is included along with
the User’s Guide.
13.19 PICDEM 17 Demonstration Board
The PICDEM 17 demonstration board is an evaluation
board that demonstrates the capabilities of several
Microchip microcontrollers, including PIC17C752,
PIC17C756A, PIC17C762 and PIC17C766. A programmed sample is included. The PRO MATE II device
programmer, or the PICSTART Plus development programmer, can be used to reprogram the device for user
tailored application development. The PICDEM 17
demonstration board supports program download and
execution from external on-board FLASH memory. A
generous prototype area is available for user hardware
expansion.
 2003 Microchip Technology Inc.
PIC16F870/871
13.20 PICDEM 18R PIC18C601/801
Demonstration Board
13.23 PICDEM USB PIC16C7X5
Demonstration Board
The PICDEM 18R demonstration board serves to assist
development of the PIC18C601/801 family of Microchip
microcontrollers. It provides hardware implementation
of both 8-bit Multiplexed/De-multiplexed and 16-bit
Memory modes. The board includes 2 Mb external
FLASH memory and 128 Kb SRAM memory, as well as
serial EEPROM, allowing access to the wide range of
memory types supported by the PIC18C601/801.
The PICDEM USB Demonstration Board shows off the
capabilities of the PIC16C745 and PIC16C765 USB
microcontrollers. This board provides the basis for
future USB products.
13.21 PICDEM LIN PIC16C43X
Demonstration Board
The powerful LIN hardware and software kit includes a
series of boards and three PICmicro microcontrollers.
The small footprint PIC16C432 and PIC16C433 are
used as slaves in the LIN communication and feature
on-board LIN transceivers. A PIC16F874 FLASH
microcontroller serves as the master. All three microcontrollers are programmed with firmware to provide
LIN bus communication.
13.22 PICkitTM 1 FLASH Starter Kit
A complete "development system in a box", the PICkit
FLASH Starter Kit includes a convenient multi-section
board for programming, evaluation, and development
of 8/14-pin FLASH PIC® microcontrollers. Powered via
USB, the board operates under a simple Windows GUI.
The PICkit 1 Starter Kit includes the user's guide (on
CD ROM), PICkit 1 tutorial software and code for various applications. Also included are MPLAB® IDE (Integrated Development Environment) software, software
and hardware "Tips 'n Tricks for 8-pin FLASH PIC®
Microcontrollers" Handbook and a USB Interface
Cable. Supports all current 8/14-pin FLASH PIC
microcontrollers, as well as many future planned
devices.
 2003 Microchip Technology Inc.
13.24 Evaluation and
Programming Tools
In addition to the PICDEM series of circuits, Microchip
has a line of evaluation kits and demonstration software
for these products.
• KEELOQ evaluation and programming tools for
Microchip’s HCS Secure Data Products
• CAN developers kit for automotive network
applications
• Analog design boards and filter design software
• PowerSmart battery charging evaluation/
calibration kits
• IrDA® development kit
• microID development and rfLabTM development
software
• SEEVAL® designer kit for memory evaluation and
endurance calculations
• PICDEM MSC demo boards for Switching mode
power supply, high power IR driver, delta sigma
ADC, and flow rate sensor
Check the Microchip web page and the latest Product
Line Card for the complete list of demonstration and
evaluation kits.
DS30569B-page 115
PIC16F870/871
NOTES:
DS30569B-page 116
 2003 Microchip Technology Inc.
PIC16F870/871
14.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings †
Ambient temperature under bias................................................................................................................ .-55 to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on any pin with respect to VSS (except VDD, MCLR. and RA4) ......................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ............................................................................................................ -0.3 to +7.5V
Voltage on MCLR with respect to VSS (Note 2) ............................................................................................0 to +13.25V
Voltage on RA4 with respect to Vss ..................................................................................................................0 to +8.5V
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 (VO < 0 or VO > 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, PORTB, and PORTE (combined) (Note 3) ...................................................200 mA
Maximum current sourced by PORTA, PORTB, and PORTE (combined) (Note 3)..............................................200 mA
Maximum current sunk by PORTC and PORTD (combined) (Note 3) .................................................................200 mA
Maximum current sourced by PORTC and PORTD (combined) (Note 3) ............................................................200 mA
Note 1: Power dissipation is calculated as follows: Pdis = VDD x {IDD - ∑ IOH} + ∑ {(VDD - VOH) x IOH} + ∑(VOl x IOL)
2: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100Ω should be used when applying a “low” level to the MCLR pin, rather than
pulling this pin directly to VSS.
3: PORTD and PORTE are not implemented on the 28-pin devices.
† 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.
 2003 Microchip Technology Inc.
DS30569B-page 117
PIC16F870/871
FIGURE 14-1:
PIC16FXXX VOLTAGE-FREQUENCY GRAPH
6.0V
5.5V
Voltage
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
20 MHz
Frequency
FIGURE 14-2:
PIC16LFXXX VOLTAGE-FREQUENCY GRAPH
6.0V
5.5V
Voltage
5.0V
4.5V
4.0V
3.5V
3.0V
Eq
2.5V
2.0V
Eq
4 MHz
ti
ua
on
n
tio
ua
2
1
10 MHz
20 MHz
Frequency
Equation 1: FMAX = (6.0 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz; VDDAPPMIN = 2.0V - 3.0V
Equation 2: FMAX = (10.0 MHz/V) (VDDAPPMIN – 3.0V) + 10 MHz; VDDAPPMIN = 3.0V - 4.0V
Note 1: VDDAPPMIN is the minimum voltage of the PICmicro® device in the application.
Note 2: FMAX has a maximum frequency of 10 MHz.
DS30569B-page 118
 2003 Microchip Technology Inc.
PIC16F870/871
14.1
DC Characteristics: PIC16F870/871 (Industrial, Extended)
PIC16LF870/871 (Commercial, Industrial)
PIC16LF870/871
(Commercial, Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for Industrial
0°C ≤ TA ≤ +70°C for Commercial
PIC16F870/871
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for Industrial
-40°C ≤ TA ≤ +125°C for Extended
Param
No.
Sym
VDD
D001
D001
D001A
Characteristic
Min
Typ† Max Units
Conditions
Supply Voltage
PIC16LF870/871
2.0
—
5.5
V
All configurations. See Figure 14-2 for
details.
PIC16F870/871
4.0
VBOR*
—
—
5.5
5.5
V
V
VBOR
—
5.5
V
All configurations.
BOR enabled, FMAX = 14 MHz (Note 7),
-40°C to +85°C
BOR enabled, FMAX = 10 MHz (Note 7),
-40°C to +125°C
D002*
VDR
RAM Data Retention
Voltage(1)
—
1.5
—
V
D003
VPOR
VDD Start Voltage to
ensure internal Power-on
Reset signal
—
Vss
—
V
D004*
SVDD
VDD Rise Rate to ensure
internal Power-on Reset
signal
0.05
—
—
D005
VBOR
Brown-out Reset
Voltage
3.7
4.0
4.35
See section on Power-on Reset for details
V/ms See section on Power-on Reset for details
V
BOREN bit in configuration word enabled
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 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 without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature also have
an impact on the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail to rail; all I/O pins tri-stated, 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 in hi-impedance state and tied to VDD and 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: Timer1 oscillator (when enabled) adds approximately 20 µA to the specification. This value is from
characterization and is for design guidance only. This is not tested.
6: The ∆ current is the additional current consumed when this peripheral is enabled. This current should be
added to the base IDD or IPD measurement.
7: When BOR is enabled, the device will operate correctly until the VBOR voltage trip point is reached.
 2003 Microchip Technology Inc.
DS30569B-page 119
PIC16F870/871
14.1
DC Characteristics: PIC16F870/871 (Industrial, Extended)
PIC16LF870/871 (Commercial, Industrial) (Continued)
PIC16LF870/871
(Commercial, Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for Industrial
0°C ≤ TA ≤ +70°C for Commercial
PIC16F870/871
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for Industrial
-40°C ≤ TA ≤ +125°C for Extended
Param
No.
Sym
IDD
Characteristic
PIC16LF870/871
D010A
D010
PIC16F870/871
D013
∆IBOR Brown-out Reset
Current(6)
IPD
Typ† Max Units
Conditions
Supply Current(2,5)
D010
D015*
Min
—
0.6
2.0
mA
XT, RC osc configuration
FOSC = 4 MHz, VDD = 3.0V (Note 4)
LP osc configuration
FOSC = 32 kHz, VDD = 3.0V, WDT disabled
—
20
35
µA
—
1.6
4
mA
—
7
15
mA
—
7
15
mA
—
85
200
µA
BOR enabled, VDD = 5.0V
XT, RC osc configuration
FOSC = 4 MHz, VDD = 5.5V (Note 4)
HS osc configuration
FOSC = 20 MHz, VDD = 5.5V, -40°C to +85°C
HS osc configuration
FOSC = 10 MHz, VDD = 5.5V, -40°C to +125°C
Power-down Current(3,5)
D020
D021
D021A
PIC16LF870/871
—
—
—
7.5
0.8
0.9
30
4.5
5
µA
µA
µA
VDD = 3.0V, WDT enabled, -40°C to +85°C
VDD = 3.0V, WDT disabled, 0°C to +70°C
VDD = 3.0V, WDT disabled, -40°C to +85°C
D020
D20A
D021
D021A
D21B
PIC16F870/871
—
—
—
—
—
10.5
10.5
1.5
1.5
1.5
42
60
16
19
30
µA
µA
µA
µA
µA
VDD = 4.0V, WDT enabled, -40°C to +85°C
VDD = 4.0V, WDT enabled, -40°C to +125°C
VDD = 4.0V, WDT disabled, -0°C to +70°C
VDD = 4.0V, WDT disabled, -40°C to +85°C
VDD = 4.0V, WDT disabled, -40°C to +125°C
—
85
200
µA
BOR enabled, VDD = 5.0V
D023*
∆IBOR Brown-out Reset
Current(6)
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 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 without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature also have
an impact on the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail to rail; all I/O pins tri-stated, 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 in hi-impedance state and tied to VDD and 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: Timer1 oscillator (when enabled) adds approximately 20 µA to the specification. This value is from
characterization and is for design guidance only. This is not tested.
6: The ∆ current is the additional current consumed when this peripheral is enabled. This current should be
added to the base IDD or IPD measurement.
7: When BOR is enabled, the device will operate correctly until the VBOR voltage trip point is reached.
DS30569B-page 120
 2003 Microchip Technology Inc.
PIC16F870/871
14.2
DC Characteristics: PIC16F870/871 (Industrial)
DC CHARACTERISTICS
Param
No.
Sym
VIL
Characteristic
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for Industrial
Operating voltage VDD range as described in DC spec Section 14.1
and Section 14.2.
Min
Typ†
Max
Units
Conditions
with TTL buffer
VSS
—
0.15 VDD
V
For entire VDD range
VSS
—
0.8V
V
4.5V ≤ VDD ≤ 5.5V
with Schmitt Trigger buffer
VSS
—
0.2 VDD
V
Input Low Voltage
I/O ports:
D030
D030A
D031
D032
MCLR, OSC1 (in RC mode)
VSS
—
0.2 VDD
V
D033
OSC1 (in XT, HS and LP)
VSS
—
0.3 VDD
V
(Note 1)
with Schmitt Trigger buffer
VSS
—
0.3 VDD
V
For entire VDD range
with SMBus
-0.5
—
0.6
V
For VDD = 4.5 to 5.5V
Ports RC3 and RC4:
D034
D034A
VIH
Input High Voltage
I/O ports:
D040
with TTL buffer
D040A
—
2.0
—
VDD
V
4.5V ≤ VDD ≤ 5.5V
0.25 VDD +
—
VDD
V
For entire VDD range
For entire VDD range
0.8V
0.8 VDD
—
VDD
V
D042
MCLR
0.8 VDD
—
VDD
V
D042A
OSC1 (XT, HS and LP)
0.7 VDD
—
VDD
V
D043
OSC1 (in RC mode)
0.9 VDD
—
VDD
V
0.7 VDD
—
VDD
V
D041
with Schmitt Trigger buffer
(Note 1)
Ports RC3 and RC4:
D044
with Schmitt Trigger buffer
D044A
D070
with SMBus
IPURB PORTB Weak Pull-up
Current
IIL
For entire VDD range
1.4
—
5.5
V
for VDD = 4.5 to 5.5V
50
250
400
µA
VDD = 5V, VPIN = VSS
Input Leakage Current
(Notes 2, 3)
D060
I/O ports
—
—
±1
µA
Vss ≤ VPIN ≤ VDD,
Pin at hi-impedance
D061
MCLR, RA4/T0CKI
—
—
±5
µA
Vss ≤ VPIN ≤ VDD
D063
OSC1
—
—
±5
µA
Vss ≤ VPIN ≤ VDD, XT, HS and
LP osc configuration
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PIC16F870/871 be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
 2003 Microchip Technology Inc.
DS30569B-page 121
PIC16F870/871
14.2
DC Characteristics: PIC16F870/871 (Industrial) (Continued)
DC CHARACTERISTICS
Param
No.
Sym
VOL
Characteristic
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for Industrial
Operating voltage VDD range as described in DC spec Section 14.1
and Section 14.2.
Min
Typ†
Max
Units
Conditions
Output Low Voltage
D080
I/O ports
—
—
0.6
V
IOL = 8.5 mA, VDD = 4.5V,
-40°C to +85°C
D083
OSC2/CLKO (RC osc config)
—
—
0.6
V
IOL = 1.6 mA, VDD = 4.5V,
-40°C to +85°C
VOH
Output High Voltage
D090
I/O ports (Note 3)
VDD – 0.7
—
—
V
IOH = -3.0 mA, VDD = 4.5V,
-40°C to +85°C
D092
OSC2/CLKO (RC osc config)
VDD – 0.7
—
—
V
IOH = -1.3 mA, VDD = 4.5V,
-40°C to +85°C
—
—
8.5
V
RA4 pin
—
—
15
pF
In XT, HS and LP modes when
external clock is used to drive
OSC1.
—
—
50
pF
—
—
400
pF
D150*
VOD
Open Drain High Voltage
Capacitive Loading Specs
on Output Pins
D100
COSC2 OSC2 pin
D101
CIO
D102
CB
D120
ED
Endurance
100K
—
—
D121
VDRW VDD for read/write
VMIN
—
5.5
V
D122
TDEW Erase/write cycle time
—
4
8
ms
E/W 25°C at 5V
All I/O pins and OSC2
(in RC mode)
SCL, SDA in I2C mode
Data EEPROM Memory
E/W 25°C at 5V
Using EECON to read/write
VMIN = min operating voltage
Program FLASH Memory
D130
EP
Endurance
1000
—
—
D131
VPR
VDD for read
VMIN
—
5.5
V
VMIN = min operating voltage
VDD for erase/write
VMIN
—
5.5
V
Using EECON to read/write,
VMIN = min operating voltage
—
4
8
ms
D132a
D133
TPEW Erase/Write cycle time
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PIC16F870/871 be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
DS30569B-page 122
 2003 Microchip Technology Inc.
PIC16F870/871
14.3
DC Characteristics: PIC16F870/871 (Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +125°C
Operating voltage VDD range as described in DC specification
(Section )
DC CHARACTERISTICS
Param
No.
Sym
VIL
Characteristic
Min
Typ†
Max
Units
Conditions
VSS
—
0.15 VDD
V
For entire VDD range
VSS
—
0.8V
V
4.5V ≤ VDD ≤ 5.5V
VSS
—
0.2 VDD
V
Input Low Voltage
I/O ports:
D030
with TTL buffer
D030A
D031
with Schmitt Trigger buffer
D032
MCLR, OSC1 (in RC mode)
VSS
—
0.2 VDD
V
D033
OSC1 (in XT, HS and LP)
VSS
—
0.3 VDD
V
(Note 1)
with Schmitt Trigger buffer
VSS
—
0.3 VDD
V
For entire VDD range
with SMBus
-0.5
—
0.6
V
For VDD = 4.5 to 5.5V
Ports RC3 and RC4:
D034
D034A
VIH
Input High Voltage
I/O ports:
D040
with TTL buffer
D040A
—
2.0
—
VDD
V
4.5V ≤ VDD ≤ 5.5V
0.25 VDD
—
VDD
V
For entire VDD range
0.8 VDD
—
VDD
V
For entire VDD range
0.8 VDD
—
VDD
V
+ 0.8V
D041
with Schmitt Trigger buffer
D042
MCLR
D042A
OSC1 (XT, HS and LP)
0.7 VDD
—
VDD
V
D043
OSC1 (in RC mode)
0.9 VDD
—
VDD
V
0.7 VDD
—
VDD
V
For entire VDD range
(Note 1)
Ports RC3 and RC4:
D044
with Schmitt Trigger buffer
D044A
with SMBus
D070A IPURB PORTB Weak Pull-up Current
IIL
1.4
—
5.5
V
For VDD = 4.5 to 5.5V
50
250
400
µA
VDD = 5V, VPIN = VSS
Input Leakage Current(2,3)
D060
I/O ports
—
—
±1
µA
Vss ≤ VPIN ≤ VDD,
Pin at hi-impedance
D061
MCLR, RA4/T0CKI
—
—
±5
µA
Vss ≤ VPIN ≤ VDD
D063
OSC1
—
—
±5
µA
Vss ≤ VPIN ≤ VDD, XT, HS
and LP osc configuration
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PIC16F87X be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
 2003 Microchip Technology Inc.
DS30569B-page 123
PIC16F870/871
14.3
DC Characteristics: PIC16F870/871 (Extended) (Continued)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +125°C
Operating voltage VDD range as described in DC specification
(Section )
DC CHARACTERISTICS
Param
No.
Sym
VOL
Characteristic
Min
Typ†
Max
Units
Conditions
Output Low Voltage
D080A
I/O ports
—
—
0.6
V
IOL = 7.0 mA, VDD = 4.5V
D083A
OSC2/CLKO (RC osc config)
—
—
0.6
V
IOL = 1.2 mA, VDD = 4.5V
I/O ports(3)
VDD – 0.7
—
—
V
IOH = -2.5 mA, VDD = 4.5V
OSC2/CLKO (RC osc config)
VDD – 0.7
—
—
V
IOH = -1.0 mA, VDD = 4.5V
—
—
8.5
V
RA4 pin
In XT, HS and LP modes when
external clock is used to drive
OSC1
VOH
D090A
D092A
D150*
VOD
Output High Voltage
Open Drain High Voltage
Capacitive Loading Specs on
Output Pins
D100
COSC2 OSC2 pin
—
—
15
pF
D101
CIO
—
—
50
pF
D102
CB
—
—
400
pF
All I/O pins and OSC2
(RC mode)
SCL, SDA (I2C mode)
Data EEPROM Memory
D120
ED
Endurance
100K
—
—
E/W 25°C at 5V
D121
VDRW VDD for read/write
VMIN
—
5.5
V
D122
TDEW Erase/write cycle time
—
4
8
ms
D130
EP
Endurance
1000
—
—
E/W 25°C at 5V
D131
VPR
VDD for read
VMIN
—
5.5
V
VMIN = min operating voltage
VDD for erase/write
VMIN
—
5.5
V
Using EECON to read/write,
VMIN = min. operating voltage
—
4
8
ms
Using EECON to read/write,
VMIN = min. operating voltage
Program FLASH Memory
D132A
D133
TPEW
Erase/Write cycle time
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PIC16F87X be driven with external clock in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
DS30569B-page 124
 2003 Microchip Technology Inc.
PIC16F870/871
14.4
Timing Parameter Symbology
The timing parameter symbols have been created
following one of the following formats:
1. TppS2ppS
3. TCC:ST
(I2C specifications only)
2. TppS
4. Ts
(I2C specifications only)
T
F
Frequency
Lowercase letters (pp) and their meanings:
pp
cc
CCP1
ck
CLKO
cs
CS
di
SDI
do
SDO
dt
Data in
io
I/O port
mc
MCLR
Uppercase letters and their meanings:
S
F
Fall
H
High
I
Invalid (Hi-impedance)
L
Low
I2C only
AA
BUF
output access
Bus free
TCC:ST (I2C specifications only)
CC
HD
Hold
ST
DAT
DATA input hold
STA
START condition
 2003 Microchip Technology Inc.
T
Time
osc
rd
rw
sc
ss
t0
t1
wr
OSC1
RD
RD or WR
SCK
SS
T0CKI
T1CKI
WR
P
R
V
Z
Period
Rise
Valid
Hi-impedance
High
Low
High
Low
SU
Setup
STO
STOP condition
DS30569B-page 125
PIC16F870/871
FIGURE 14-3:
LOAD CONDITIONS
Load condition 2
Load condition 1
VDD/2
RL
CL
Pin
CL
Pin
VSS
VSS
RL = 464Ω
CL = 50 pF
15 pF
Note:
FIGURE 14-4:
for all pins except OSC2, but including PORTD and PORTE outputs as ports
for OSC2 output
PORTD and PORTE are not implemented on the PIC16F870.
EXTERNAL CLOCK TIMING
Q4
Q1
Q2
Q3
Q4
Q1
OSC1
1
3
3
4
4
2
CLKO
DS30569B-page 126
 2003 Microchip Technology Inc.
PIC16F870/871
TABLE 14-1:
Param
No.
Sym
FOSC
EXTERNAL CLOCK TIMING REQUIREMENTS
Characteristic
External CLKI Frequency
(Note 1)
Oscillator Frequency
(Note 1)
1
TOSC
External CLKI Period
(Note 1)
Oscillator Period
(Note 1)
Min
Typ†
Max
Units
Conditions
DC
—
4
MHz XT and RC Osc mode
DC
—
4
MHz HS Osc mode (-04)
DC
—
20
MHz HS Osc mode (-20)
DC
—
200
kHz
DC
—
4
MHz RC Osc mode
0.1
—
4
MHz XT Osc mode
4
5
—
—
20
200
MHz HS Osc mode
kHz LP Osc mode
LP Osc mode
250
—
—
ns
XT and RC Osc mode
250
—
—
ns
HS Osc mode (-04)
50
—
—
ns
HS Osc mode (-20)
5
—
—
µs
LP Osc mode
250
—
—
ns
RC Osc mode
250
—
10,000
ns
XT Osc mode
250
—
250
ns
HS Osc mode (-04)
50
—
250
ns
HS Osc mode (-20)
5
—
—
µs
LP Osc mode
2
TCY
Instruction Cycle Time
(Note 1)
200
TCY
DC
ns
TCY = 4/FOSC
3
TosL,
TosH
External Clock in (OSC1) High
or Low Time
100
—
—
ns
XT oscillator
2.5
—
—
µs
LP oscillator
15
—
—
ns
HS oscillator
TosR,
TosF
External Clock in (OSC1) Rise
or Fall Time
—
—
25
ns
XT oscillator
4
—
—
50
ns
LP oscillator
—
—
15
ns
HS oscillator
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values
are based on characterization data for that particular oscillator type under standard operating conditions
with the device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at "min." values
with an external clock applied to the OSC1/CLKI pin. When an external clock input is used, the "Max."
cycle time limit is "DC" (no clock) for all devices.
 2003 Microchip Technology Inc.
DS30569B-page 127
PIC16F870/871
FIGURE 14-5:
CLKO AND I/O TIMING
Q1
Q4
Q2
Q3
OSC1
11
10
CLKO
13
19
14
12
18
16
I/O Pin
(Input)
15
17
I/O Pin
(Output)
New Value
Old Value
20, 21
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-2:
Param
No.
CLKO AND I/O TIMING REQUIREMENTS
Min
Typ†
Max
TosH2ckL OSC1↑ to CLKO↓
—
75
200
ns
(Note 1)
11*
TosH2ckH OSC1↑ to CLKO↑
—
75
200
ns
(Note 1)
12*
TckR
CLKO rise time
—
35
100
ns
(Note 1)
13*
TckF
CLKO fall time
—
35
100
ns
(Note 1)
14*
TckL2ioV
CLKO↓ to Port out valid
—
—
0.5 TCY + 20
ns
(Note 1)
15*
TioV2ckH Port in valid before CLKO↑
TOSC + 200
—
—
ns
(Note 1)
16*
TckH2ioI
0
—
—
ns
(Note 1)
17*
TosH2ioV OSC1↑ (Q1 cycle) to Port out valid
—
100
255
ns
18*
TosH2ioI
Standard (F)
100
—
—
ns
Extended (LF)
200
—
—
ns
19*
TioV2osH Port input valid to OSC1↑ (I/O in setup time)
0
—
—
ns
20*
TIOR
Standard (F)
—
10
40
ns
Extended (LF)
—
—
145
ns
Standard (F)
—
10
40
ns
Extended (LF)
—
—
145
ns
10*
21*
Sym
TIOF
Characteristic
Port in hold after CLKO↑
OSC1↑ (Q2 cycle) to Port input
invalid (I/O in hold time)
Port output rise time
Port output fall time
Units Conditions
22††*
TINP
INT pin high or low time
TCY
—
—
ns
23††*
TRBP
RB7:RB4 change INT high or low time
TCY
—
—
ns
*
†
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
†† These parameters are asynchronous events not related to any internal clock edges.
Note 1: Measurements are taken in RC mode where CLKO output is 4 x TOSC.
DS30569B-page 128
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 14-6:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
Osc
Time-out
Internal
RESET
Watchdog
Timer
Reset
31
34
34
I/O Pins
Note: Refer to Figure 14-3 for load conditions.
FIGURE 14-7:
BROWN-OUT RESET TIMING
VBOR
VDD
35
TABLE 14-3:
Param
No.
Sym
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER,
AND BROWN-OUT RESET REQUIREMENTS
Characteristic
Min
Typ†
Max
Units
Conditions
30
TmcL
MCLR Pulse Width (low)
2
—
—
µs
VDD = 5V, -40°C to +85°C
31*
TWDT
Watchdog Timer Time-out Period
(No Prescaler)
7
18
33
ms
VDD = 5V, -40°C 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 = 5V, -40°C to +85°C
34
TIOZ
I/O Hi-impedance from MCLR Low or
Watchdog Timer Reset
—
—
2.1
µs
TBOR
Brown-out Reset pulse width
100
—
—
µs
35
VDD ≤ VBOR (D005)
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
 2003 Microchip Technology Inc.
DS30569B-page 129
PIC16F870/871
FIGURE 14-8:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
RA4/T0CKI
41
40
42
RC0/T1OSO/T1CKI
46
45
47
48
TMR0 or
TMR1
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-4:
Param
No.
TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Sym
Characteristic
40*
Tt0H
T0CKI High Pulse Width
41*
Tt0L
T0CKI Low Pulse Width
No Prescaler
With Prescaler
No Prescaler
With Prescaler
42*
Tt0P
T0CKI Period
No Prescaler
With Prescaler
45*
46*
Tt1H
Tt1L
T1CKI High Time
T1CKI Low Time
Synchronous, Prescaler = 1
Tt1P
48
Units
0.5 TCY + 20
—
—
ns
—
—
ns
—
—
ns
10
—
—
ns
TCY + 40
—
—
ns
—
—
ns
N = prescale value
(2, 4, ..., 256)
Must also meet
parameter 47
Greater of:
20 or TCY + 40
N
—
ns
—
—
ns
25
—
—
ns
Asynchronous
Standard(F)
30
—
—
ns
Extended(LF)
50
—
—
ns
0.5 TCY + 20
—
—
ns
Synchronous,
Standard(F)
Prescaler = 2,4,8 Extended(LF)
15
—
—
ns
25
—
—
ns
Asynchronous
30
—
—
ns
Standard(F)
T1CKI input period Synchronous
50
Standard(F)
Greater of:
30 or TCY + 40
N
Extended(LF)
Greater of:
50 or TCY + 40
N
—
—
ns
—
—
ns
Must also meet
parameter 42
Must also meet
parameter 47
N = prescale value
(1, 2, 4, 8)
N = prescale value
(1, 2, 4, 8)
Standard(F)
60
—
—
Extended(LF)
100
—
—
ns
DC
—
200
kHz
2 TOSC
—
7 TOSC
—
Timer1 oscillator input frequency range
(oscillator enabled by setting bit T1OSCEN)
Must also meet
parameter 42
10
—
Synchronous, Prescaler = 1
Conditions
0.5 TCY + 20
15
TCKEZtmr1 Delay from external clock edge to timer increment
*
†
Max
0.5 TCY + 20
Asynchronous
Ft1
Typ†
Synchronous,
Standard(F)
Prescaler = 2,4,8 Extended(LF)
Extended(LF)
47*
Min
ns
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested.
DS30569B-page 130
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 14-9:
CAPTURE/COMPARE/PWM TIMINGS (CCP1)
RC2/CCP1
(Capture Mode)
50
51
52
RC2/CCP1
(Compare or PWM Mode)
53
54
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-5:
Param
No.
50*
51*
CAPTURE/COMPARE/PWM REQUIREMENTS (CCP1)
Sym
TccL
TccH
Characteristic
*
CCP1
input low
time
CCP1 input high time
Min
No Prescaler
With Prescaler
Standard(F)
Extended(LF)
0.5 TCY + 20
—
—
ns
10
—
—
ns
20
—
—
ns
0.5 TCY + 20
—
—
ns
Standard(F)
10
—
—
ns
Extended(LF)
20
—
—
ns
3 TCY + 40
N
—
—
ns
No Prescaler
With Prescaler
Typ† Max Units
52*
TccP
CCP1 input period
53*
TccR
CCP1 output rise time
Standard(F)
—
10
25
ns
Extended(LF)
—
25
50
ns
54*
TccF
CCP1 output fall time
Standard(F)
—
10
25
ns
Extended(LF)
—
25
45
ns
*
†
Conditions
N = prescale value
(1,4 or 16)
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
 2003 Microchip Technology Inc.
DS30569B-page 131
PIC16F870/871
FIGURE 14-10:
PARALLEL SLAVE PORT TIMING (PIC16F871 ONLY)
RE2/CS
RE0/RD
RE1/WR
65
RD7:RD0
62
64
63
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-6:
Param
No.
PARALLEL SLAVE PORT REQUIREMENTS (PIC16F871 ONLY)
Sym
Characteristic
Min Typ† Max Units
62
TdtV2wrH
Data in valid before WR↑ or CS↑ (setup time)
20
25
—
—
—
—
ns
ns
63*
TwrH2dtI
WR↑ or CS↑ to data–in invalid (hold time) Standard(F)
20
—
—
ns
35
—
—
ns
64
TrdL2dtV
RD↓ and CS↓ to data–out valid
—
—
—
—
80
90
ns
ns
10
—
30
ns
Extended(LF)
65
TrdH2dtI
*
†
RD↑ or CS↓ to data–out invalid
Conditions
Extended range only
Extended range only
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS30569B-page 132
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 14-11:
USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RC6/TX/CK
pin
121
121
RC7/RX/DT
pin
120
122
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-7:
Param
No.
120
121
122
USART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Sym
Characteristic
TckH2dtV
SYNC XMIT (MASTER & SLAVE)
Clock high to data out valid
Tckrf
Tdtrf
†
Min
Typ†
Max
Units Conditions
Standard(F)
—
—
80
ns
Extended(LF)
—
—
100
ns
Clock out rise time and fall time
(Master mode)
Standard(F)
—
—
45
ns
Extended(LF)
—
—
50
ns
Data out rise time and fall time
Standard(F)
—
—
45
ns
Extended(LF)
—
—
50
ns
Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
FIGURE 14-12:
USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
RC6/TX/CK
pin
RC7/RX/DT
pin
125
126
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-8:
Param
No.
USART SYNCHRONOUS RECEIVE REQUIREMENTS
Sym
125
TdtV2ckL
126
TckL2dtl
†
Characteristic
Min
Typ†
Max
Units
SYNC RCV (MASTER & SLAVE)
Data setup before CK ↓ (DT setup time)
15
—
—
ns
Data hold after CK ↓ (DT hold time)
15
—
—
ns
Conditions
Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
 2003 Microchip Technology Inc.
DS30569B-page 133
PIC16F870/871
TABLE 14-9:
PIC16F870/871 (INDUSTRIAL)
PIC16LF870/871 (INDUSTRIAL)
Param
Sym
No.
Characteristic
Min
Typ†
Max
Units
Conditions
A01
NR
Resolution
—
—
10-bits
bit
VREF = VDD = 5.12V,
VSS ≤ VAIN ≤ VREF
A03
EIL
Integral linearity error
—
—
<±1
LSb
VREF = VDD = 5.12V,
VSS ≤ VAIN ≤ VREF
A04
EDL
Differential linearity error
—
—
<±1
LSb
VREF = VDD = 5.12V,
VSS ≤ VAIN ≤ VREF
A06
EOFF
Offset error
—
—
<±1
LSb
VREF = VDD = 5.12V,
VSS ≤ VAIN ≤ VREF
A07
EGN
Gain error
—
—
<±1
LSb
VREF = VDD = 5.12V,
VSS ≤ VAIN ≤ VREF
A10
—
Monotonicity(3)
—
guaranteed
—
—
A20
VREF
Reference voltage (VREF+ – VREF-)
2.0V
—
VDD + 0.3
V
VSS ≤ VAIN ≤ VREF
A21
VREF+ Reference voltage High
VDD – 2.5V
VDD + 0.3V
V
Must meet spec. A20
A22
VREF- Reference voltage Low
VSS – 0.3V
VREF+ – 2.0V
V
Must meet spec. A20
A25
VAIN
Analog input voltage
A30
ZAIN
Recommended impedance of
analog voltage source
A40
IAD
A/D conversion
current (VDD)
A50
IREF
*
†
Note 1:
2:
3:
VSS – 0.3
—
VREF + 0.3
V
—
—
10.0
kΩ
Standard(F)
—
220
—
µA
Extended(LF)
—
90
—
µA
10
—
1000
µA
—
—
10
µA
VREF input current (Note 2)
Average current consumption
when A/D is on (Note 1).
During VAIN acquisition.
Based on differential of VHOLD
to VAIN to charge CHOLD, see
Section 10.1.
During A/D Conversion cycle
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
When A/D is off, it will not consume any current other than minor leakage current. The power-down current spec includes
any such leakage from the A/D module.
VREF current is from RA3 pin or VDD pin, whichever is selected as reference input.
The A/D conversion result never decreases with an increase in the input voltage, and has no missing codes.
DS30569B-page 134
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 14-13:
A/D CONVERSION TIMING
1 TCY
BSF ADCON0, GO
(TOSC/2)(1)
131
Q4
130
A/D CLK
132
9
A/D DATA
8
...
7
...
2
1
0
NEW_DATA
OLD_DATA
ADRES
ADIF
GO
DONE
SAMPLING STOPPED
SAMPLE
Note 1:
If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
TABLE 14-10: A/D CONVERSION REQUIREMENTS
Param
No.
130
Sym
TAD
Characteristic
A/D clock period
Min
Typ†
Max
Units
Standard(F)
1.6
—
—
µs
TOSC based, VREF ≥ 3.0V
Extended(LF)
3.0
—
—
µs
TOSC based, VREF ≥ 2.0V
Standard(F)
2.0
4.0
6.0
µs
A/D RC Mode
Extended(LF)
3.0
6.0
9.0
µs
A/D RC Mode
—
12
TAD
(Note 2)
40
—
µs
10*
—
—
µs
The minimum time is the amplifier settling time. This may be
used if the "new" input voltage
has not changed by more than
1 LSb (i.e., 20.0 mV @ 5.12V)
from the last sampled voltage
(as stated on CHOLD).
—
TOSC/2 §
—
—
If the A/D clock source is
selected as RC, a time of TCY is
added before the A/D clock
starts. This allows the SLEEP
instruction to be executed.
131
TCNV
Conversion time (not including S/H time)
(Note 1)
132
TACQ
Acquisition time
134
TGO
*
†
§
Note 1:
2:
Q4 to A/D clock start
Conditions
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
This specification ensured by design.
ADRES register may be read on the following TCY cycle.
See Section 10.1 for min conditions.
 2003 Microchip Technology Inc.
DS30569B-page 135
PIC16F870/871
NOTES:
DS30569B-page 136
 2003 Microchip Technology Inc.
PIC16F870/871
15.0
DC AND AC CHARACTERISTICS GRAPHS AND TABLES
Note:
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore, outside the warranted range.
“Typical” represents the mean of the distribution at 25°C. “Maximum” or “minimum” represents (mean + 3σ) or (mean - 3σ)
respectively, where σ is a standard deviation, over the whole temperature range.
FIGURE 15-1:
TYPICAL IDD vs. FOSC OVER VDD (HS MODE)
7
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
6
5
5.5V
I DD (mA)
4
5.0V
4.5V
3
4.0V
2
3.5V
3.0V
1
2 .5 V
2 .0 V
0
4
6
8
10
12
14
16
18
20
F O S C (M H z )
FIGURE 15-2:
MAXIMUM IDD vs. FOSC OVER VDD (HS MODE)
8
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
7
6
5.5V
5
I DD (mA)
5.0V
4
4.5V
4.0V
3
3.5V
2
3.0V
1
2.5V
2.0V
0
4
6
8
10
12
14
16
18
20
F O S C (M H z )
 2003 Microchip Technology Inc.
DS30569B-page 137
PIC16F870/871
FIGURE 15-3:
TYPICAL IDD vs. FOSC OVER VDD (XT MODE)
1.6
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
1.4
5.5V
1.2
5.0V
1.0
I DD (mA)
4.5V
0.8
4.0V
3.5V
0.6
3.0V
0.4
2.5V
2.0V
0.2
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
3.5
4.0
F OSC (MHz)
FIGURE 15-4:
MAXIMUM IDD vs. FOSC OVER VDD (LP MODE)
2.0
1.8
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
1.6
5.5V
1.4
5.0V
I DD (mA)
1.2
4.5V
1.0
4.0V
0.8
3.5V
0.6
3.0V
2.5V
0.4
2.0V
0.2
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
F OSC (MHz)
DS30569B-page 138
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 15-5:
TYPICAL IDD vs. FOSC OVER VDD (LP MODE)
90
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
80
5.5V
70
5.0V
60
IDD (uA)
4.5V
50
4.0V
3.5V
40
3.0V
30
2.5V
20
2.0V
10
0
20
30
40
50
60
70
80
90
100
F OS C (kH z )
FIGURE 15-6:
MAXIMUM IDD vs. FOSC OVER VDD (XT MODE)
120
110
5.5V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
100
5.0V
90
80
4.5V
IDD (uA)
70
4.0V
60
3.5V
50
3.0V
40
2.5V
30
2.0V
20
10
0
20
30
40
50
60
70
80
90
100
F OSC (kH z )
 2003 Microchip Technology Inc.
DS30569B-page 139
PIC16F870/871
FIGURE 15-7:
AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R (RC MODE, C = 20 pF, 25°C)
4.0
3.3kΩ
3.5
3.0
5.1kΩ
Freq (MHz)
2.5
2.0
10kΩ
1.5
1.0
0.5
100kΩ
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
FIGURE 15-8:
AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R (RC MODE, C = 100 pF, 25°C)
2.0
1.8
1.6
3.3 kΩ
Freq (MHz)
1.4
1.2
5.1 kΩ
1.0
0.8
0.6
10 kΩ
0.4
0.2
100 kΩ
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V D D (V )
DS30569B-page 140
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 15-9:
AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R (RC MODE, C = 300 pF, 25°C)
1.0
0.9
0.8
3.3 kΩ
Freq (MHz)
0.7
0.6
5.1 kΩ
0.5
0.4
0.3
10 kΩ
0.2
0.1
100 kΩ
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
5.0
5.5
V D D (V)
FIGURE 15-10:
IPD vs. VDD (SLEEP MODE, ALL PERIPHERALS DISABLED)
100.00
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
Max (125C)
10.00
I PD (µ A)
Max (85C)
1.00
0.10
Typ (25C)
0.01
2.0
2.5
3.0
3.5
4.0
4.5
VDD (V)
 2003 Microchip Technology Inc.
DS30569B-page 141
PIC16F870/871
FIGURE 15-11:
∆IBOR vs. VDD OVER TEMPERATURE
1.2
Note:
1.0
Device current in RESET
depends on Oscillator mode,
frequency and circuit.
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
Max RESET
0.6
∆I
(mA)
0.8
Indeterminate
State
Typ RESET (25°C)
0.4
Device in SLEEP
Device in RESET
0.2
Max SLEEP
Typ SLEEP (25°C)
0.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V D D (V)
FIGURE 15-12:
TYPICAL AND MAXIMUM ∆ITMR1 vs. VDD OVER TEMPERATURE
(-10°C TO 70°C, TIMER1 WITH OSCILLATOR, XTAL=32 kHZ, C1 AND C2=50 pF)
90
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
80
70
∆ ITMR1 (uA)
60
50
40
Max
30
Ty p (25C)
20
10
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V )
DS30569B-page 142
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 15-13:
TYPICAL AND MAXIMUM ∆IWDT vs. VDD OVER TEMPERATURE
14
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
12
10
∆ I WDT (uA)
Max (85C)
8
Typ (25C)
6
4
2
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
FIGURE 15-14:
TYPICAL, MINIMUM AND MAXIMUM WDT PERIOD vs. VDD (-40°C TO 125°C)
60
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
50
WDT Period (ms)
40
Max (125C)
30
20
Typ (25C)
Min (-40C)
10
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
 2003 Microchip Technology Inc.
DS30569B-page 143
PIC16F870/871
FIGURE 15-15:
AVERAGE WDT PERIOD vs. VDD OVER TEMPERATURE (-40°C TO 125°C)
50
45
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
40
125C
35
WDT Period (ms)
85C
30
25
25C
20
-40C
15
10
5
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
FIGURE 15-16:
TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 5V, -40°C TO 125°C)
5.0
Max (-40C)
4.5
Typ (25C)
VOH (V)
4.0
3.5
Min (125C)
3.0
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
2.5
2.0
0
5
10
15
20
25
I OH (-mA)
DS30569B-page 144
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 15-17:
TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 3V, -40°C TO 125°C)
3.0
Max (-40C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
2.5
Typ (25C)
VOH (V)
2.0
1.5
Min (125C)
1.0
0.5
0.0
0
5
10
15
20
25
I OH (-mA)
FIGURE 15-18:
TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 5V, -40°C TO 125°C)
2.0
1.8
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
1.6
1.4
VOL (V)
1.2
1.0
Max (125C)
0.8
0.6
Typ (25C)
0.4
Min (-40C)
0.2
0.0
0
5
10
15
20
25
I OL (-mA)
 2003 Microchip Technology Inc.
DS30569B-page 145
PIC16F870/871
FIGURE 15-19:
TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 3V, -40°C TO 125°C)
3.0
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
2.5
VOL (V)
2.0
1.5
Max (125C)
1.0
Typ (25C)
0.5
Min (-40C)
0.0
0
5
10
15
20
25
I OL (-mA)
FIGURE 15-20:
MINIMUM AND MAXIMUM VIN vs. VDD, (TTL INPUT, -40°C TO 125°C)
1.8
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
1.6
Max (-40C)
1.4
1.2
VIN (V)
Min (125C)
1.0
0.8
0.6
0.4
0.2
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
DS30569B-page 146
 2003 Microchip Technology Inc.
PIC16F870/871
FIGURE 15-21:
MINIMUM AND MAXIMUM VIN vs. VDD (ST INPUT, -40°C TO 125°C)
4.5
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
4.0
3.5
Max High (125C)
3.0
Min High (-40C)
VIN (V)
2.5
2.0
Max Low (125C)
1.5
Min Low (-40C)
1.0
0.5
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
FIGURE 15-22:
MINIMUM AND MAXIMUM VIN vs. VDD (I2C INPUT, -40°C TO 125°C)
3.5
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
3.0
Max High (125C)
2.5
Min High (-40C)
Max Low (125C)
V IN (V)
2.0
Min Low (25C)
1.5
1.0
0.5
0.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V DD (V)
 2003 Microchip Technology Inc.
DS30569B-page 147
PIC16F870/871
NOTES:
DS30569B-page 148
 2003 Microchip Technology Inc.
PIC16F870/871
16.0
PACKAGING INFORMATION
16.1
Package Marking Information
28-Lead PDIP (Skinny DIP)
Example
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN
28-Lead SOIC
28-Lead SSOP
XXXXXXXXXXXX
XXXXXXXXXXXX
YYWWNNN
Legend: XX...X
Y
YY
WW
NNN
*
0317017
Example
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN
Note:
PIC16F870-I/SP
PIC16F870-I/SO
0310017
Example
PIC16F870-I/SS
0320017
Customer specific information*
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line thus limiting the number of available characters
for customer specific information.
Standard PICmicro device marking consists of Microchip part number, year code, week code, and
traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check
with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP
price.
 2003 Microchip Technology Inc.
DS30569B-page 149
PIC16F870/871
Package Marking Information (Cont’d)
40-Lead PDIP
Example
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
YYWWNNN
44-Lead TQFP
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
44-Lead PLCC
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
DS30569B-page 150
PIC16F871-I/P
0312017
Example
PIC16F871
-I/PT
0320017
Example
PIC16F871
-I/L
0320017
 2003 Microchip Technology Inc.
PIC16F870/871
28-Lead Skinny Plastic Dual In-line (SP) – 300 mil (PDIP)
E1
D
2
n
1
α
E
A2
A
L
c
β
B1
A1
eB
Units
Number of Pins
Pitch
p
B
Dimension Limits
n
p
INCHES*
MIN
NOM
MILLIMETERS
MAX
MIN
NOM
28
MAX
28
.100
2.54
Top to Seating Plane
A
.140
.150
.160
3.56
3.81
4.06
Molded Package Thickness
A2
.125
.130
.135
3.18
3.30
3.43
8.26
Base to Seating Plane
A1
.015
Shoulder to Shoulder Width
E
.300
.310
.325
7.62
7.87
Molded Package Width
E1
.275
.285
.295
6.99
7.24
7.49
Overall Length
D
1.345
1.365
1.385
34.16
34.67
35.18
Tip to Seating Plane
L
c
.125
.130
.135
3.18
3.30
3.43
.008
.012
.015
0.20
0.29
0.38
B1
.040
.053
.065
1.02
1.33
1.65
Lead Thickness
Upper Lead Width
Lower Lead Width
Overall Row Spacing
Mold Draft Angle Top
Mold Draft Angle Bottom
§
0.38
B
.016
.019
.022
0.41
0.48
0.56
eB
α
.320
.350
.430
8.13
8.89
10.92
β
5
10
15
5
10
15
5
10
15
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimension D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MO-095
Drawing No. C04-070
 2003 Microchip Technology Inc.
DS30569B-page 151
PIC16F870/871
28-Lead Plastic Small Outline (SO) – Wide, 300 mil (SOIC)
E
E1
p
D
B
2
1
n
h
α
45°
c
A2
A
φ
β
L
Units
Dimension Limits
n
p
Number of Pins
Pitch
Overall Height
Molded Package Thickness
Standoff §
Overall Width
Molded Package Width
Overall Length
Chamfer Distance
Foot Length
Foot Angle Top
Lead Thickness
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
A
A2
A1
E
E1
D
h
L
φ
c
B
α
β
A1
MIN
.093
.088
.004
.394
.288
.695
.010
.016
0
.009
.014
0
0
INCHES*
NOM
28
.050
.099
.091
.008
.407
.295
.704
.020
.033
4
.011
.017
12
12
MAX
.104
.094
.012
.420
.299
.712
.029
.050
8
.013
.020
15
15
MILLIMETERS
NOM
28
1.27
2.36
2.50
2.24
2.31
0.10
0.20
10.01
10.34
7.32
7.49
17.65
17.87
0.25
0.50
0.41
0.84
0
4
0.23
0.28
0.36
0.42
0
12
0
12
MIN
MAX
2.64
2.39
0.30
10.67
7.59
18.08
0.74
1.27
8
0.33
0.51
15
15
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-013
Drawing No. C04-052
DS30569B-page 152
 2003 Microchip Technology Inc.
PIC16F870/871
28-Lead Plastic Shrink Small Outline (SS) – 209 mil, 5.30 mm (SSOP)
E
E1
p
D
B
2
1
n
α
A
c
A2
φ
A1
L
β
Units
Dimension Limits
n
p
Number of Pins
Pitch
Overall Height
Molded Package Thickness
Standoff §
Overall Width
Molded Package Width
Overall Length
Foot Length
Lead Thickness
Foot Angle
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
A
A2
A1
E
E1
D
L
c
φ
B
α
β
MIN
.068
.064
.002
.299
.201
.396
.022
.004
0
.010
0
0
INCHES
NOM
28
.026
.073
.068
.006
.309
.207
.402
.030
.007
4
.013
5
5
MAX
.078
.072
.010
.319
.212
.407
.037
.010
8
.015
10
10
MILLIMETERS*
NOM
MAX
28
0.65
1.73
1.85
1.98
1.63
1.73
1.83
0.05
0.15
0.25
7.59
7.85
8.10
5.11
5.25
5.38
10.06
10.20
10.34
0.56
0.75
0.94
0.10
0.18
0.25
0.00
101.60
203.20
0.25
0.32
0.38
0
5
10
0
5
10
MIN
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-150
Drawing No. C04-073
 2003 Microchip Technology Inc.
DS30569B-page 153
PIC16F870/871
40-Lead Plastic Dual In-line (P) – 600 mil (PDIP)
E1
D
α
2
1
n
E
A2
A
L
c
β
B1
A1
eB
p
B
Units
Dimension Limits
n
p
MIN
INCHES*
NOM
40
.100
.175
.150
MAX
MILLIMETERS
NOM
40
2.54
4.06
4.45
3.56
3.81
0.38
15.11
15.24
13.46
13.84
51.94
52.26
3.05
3.30
0.20
0.29
0.76
1.27
0.36
0.46
15.75
16.51
5
10
5
10
MIN
Number of Pins
Pitch
Top to Seating Plane
A
.160
.190
Molded Package Thickness
A2
.140
.160
Base to Seating Plane
.015
A1
Shoulder to Shoulder Width
E
.595
.600
.625
Molded Package Width
E1
.530
.545
.560
Overall Length
D
2.045
2.058
2.065
Tip to Seating Plane
L
.120
.130
.135
c
Lead Thickness
.008
.012
.015
Upper Lead Width
B1
.030
.050
.070
Lower Lead Width
B
.014
.018
.022
Overall Row Spacing
§
eB
.620
.650
.680
α
Mold Draft Angle Top
5
10
15
β
Mold Draft Angle Bottom
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MO-011
Drawing No. C04-016
DS30569B-page 154
MAX
4.83
4.06
15.88
14.22
52.45
3.43
0.38
1.78
0.56
17.27
15
15
 2003 Microchip Technology Inc.
PIC16F870/871
44-Lead Plastic Thin Quad Flatpack (PT) 10x10x1 mm Body, 1.0/0.10 mm Lead Form (TQFP)
E
E1
#leads=n1
p
D1
D
2
1
B
n
CH x 45 °
α
A
c
φ
β
L
A1
A2
(F)
Units
Dimension Limits
n
p
Number of Pins
Pitch
Pins per Side
Overall Height
Molded Package Thickness
Standoff §
Foot Length
Footprint (Reference)
Foot Angle
Overall Width
Overall Length
Molded Package Width
Molded Package Length
Lead Thickness
Lead Width
Pin 1 Corner Chamfer
Mold Draft Angle Top
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
n1
A
A2
A1
L
(F)
φ
E
D
E1
D1
c
B
CH
α
β
MIN
.039
.037
.002
.018
0
.463
.463
.390
.390
.004
.012
.025
5
5
INCHES
NOM
44
.031
11
.043
.039
.004
.024
.039
3.5
.472
.472
.394
.394
.006
.015
.035
10
10
MAX
.047
.041
.006
.030
7
.482
.482
.398
.398
.008
.017
.045
15
15
MILLIMETERS*
NOM
44
0.80
11
1.00
1.10
0.95
1.00
0.05
0.10
0.45
0.60
1.00
0
3.5
11.75
12.00
11.75
12.00
9.90
10.00
9.90
10.00
0.09
0.15
0.30
0.38
0.64
0.89
5
10
5
10
MIN
MAX
1.20
1.05
0.15
0.75
7
12.25
12.25
10.10
10.10
0.20
0.44
1.14
15
15
Notes:
Dimensions D1 and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-026
Drawing No. C04-076
 2003 Microchip Technology Inc.
DS30569B-page 155
PIC16F870/871
44-Lead Plastic Leaded Chip Carrier (L) – Square (PLCC)
E
E1
#leads=n1
D1 D
n 1 2
CH2 x 45 °
CH1 x 45 °
α
A3
A2
35°
A
B1
B
c
β
E2
Units
Dimension Limits
n
p
A1
p
D2
INCHES*
MIN
NOM
44
.050
11
.165
.173
.145
.153
.020
.028
.024
.029
.040
.045
.000
.005
.685
.690
.685
.690
.650
.653
.650
.653
.590
.620
.590
.620
.008
.011
.026
.029
.013
.020
0
5
0
5
MAX
MILLIMETERS
NOM
44
1.27
11
4.19
4.39
3.68
3.87
0.51
0.71
0.61
0.74
1.02
1.14
0.00
0.13
17.40
17.53
17.40
17.53
16.51
16.59
16.51
16.59
14.99
15.75
14.99
15.75
0.20
0.27
0.66
0.74
0.33
0.51
0
5
0
5
MIN
Number of Pins
Pitch
Pins per Side
n1
Overall Height
A
.180
.160
Molded Package Thickness
A2
Standoff §
A1
.035
A3
Side 1 Chamfer Height
.034
Corner Chamfer 1
CH1
.050
Corner Chamfer (others)
CH2
.010
Overall Width
E
.695
Overall Length
D
.695
Molded Package Width
E1
.656
Molded Package Length
D1
.656
Footprint Width
E2
.630
Footprint Length
.630
D2
c
Lead Thickness
.013
Upper Lead Width
B1
.032
B
.021
Lower Lead Width
α
Mold Draft Angle Top
10
β
Mold Draft Angle Bottom
10
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MO-047
Drawing No. C04-048
DS30569B-page 156
MAX
4.57
4.06
0.89
0.86
1.27
0.25
17.65
17.65
16.66
16.66
16.00
16.00
0.33
0.81
0.53
10
10
 2003 Microchip Technology Inc.
PIC16F870/871
APPENDIX A:
REVISION HISTORY
APPENDIX B:
Revision A (December 1999)
DEVICE
DIFFERENCES
The differences between the devices listed in this data
sheet are shown in Table B-1.
Original data sheet for the PIC16F870/871 family.
Revision B (April 2003)
This revision includes the DC and AC Characteristics
Graphs and Tables. The Electrical Specifications in
Section 14.0 have been updated and there have been
minor corrections to the data sheet text.
TABLE B-1:
DEVICE DIFFERENCES
Feature
PIC16F870
PIC16F871
On-chip Program Memory (Kbytes)
2K
2K
Data Memory (bytes)
128
128
Boot Block (bytes)
2048
512
Timer1 Low Power Option
Yes
No
Ports A, B, C
Ports A, B, C, D, E
5
8
I/O Ports
A/D Channels
External Memory Interface
Package Types
 2003 Microchip Technology Inc.
No
No
28-pin DIP, SOIC, SSOP
40-pin PDIP, 44-pin PLCC, TQFP
DS30569B-page 157
PIC16F870/871
APPENDIX C:
CONVERSION
CONSIDERATIONS
This appendix discusses the considerations for converting from previous versions of a device to the ones
listed in this data sheet. Typically, these changes are
due to the differences in the process technology used.
An example of this type of conversion is from a
PIC17C756 to a PIC18F8720.
Not Applicable
APPENDIX D:
MIGRATION FROM
MID-RANGE TO
ENHANCED DEVICES
A detailed discussion of the differences between the
mid-range MCU devices (i.e., PIC16CXXX) and the
enhanced devices (i.e., PIC18FXXX) is provided in
AN716, “Migrating Designs from PIC16C74A/74B to
PIC18C442.” The changes discussed, while device
specific, are generally applicable to all mid-range to
enhanced device migrations.
This Application Note is available as Literature Number
DS00716.
DS30569B-page 158
 2003 Microchip Technology Inc.
PIC16F870/871
APPENDIX E:
MIGRATION FROM
HIGH-END TO
ENHANCED DEVICES
A detailed discussion of the migration pathway and differences between the high-end MCU devices (i.e.,
PIC17CXXX) and the enhanced devices (i.e.,
PIC18FXXXX) is provided in AN726, “PIC17CXXX to
PIC18CXXX Migration.” This Application Note is
available as Literature Number DS00726.
 2003 Microchip Technology Inc.
DS30569B-page 159
PIC16F870/871
NOTES:
DS30569B-page 160
 2003 Microchip Technology Inc.
PIC16F870/871
INDEX
A
A/D ...................................................................................... 79
Acquisition Requirements ........................................... 82
ADCON0 Register....................................................... 79
ADCON1 Register....................................................... 79
ADIF Bit....................................................................... 80
ADRESH Register....................................................... 79
ADRESL Register ....................................................... 79
Analog Port Pins ................................................... 41, 42
Associated Registers and Bits .................................... 85
Calculating Acquisition Time....................................... 82
Configuring Analog Port Pins...................................... 83
Configuring the Interrupt ............................................. 81
Configuring the Module............................................... 81
Conversion Clock........................................................ 83
Conversions ................................................................ 84
Delays ......................................................................... 82
Effects of a RESET ..................................................... 85
GO/DONE Bit.............................................................. 80
Internal Sampling Switch (Rss) Impedance ................ 82
Operation During SLEEP ............................................ 85
Result Registers.......................................................... 84
Source Impedance...................................................... 82
Time Delays ................................................................ 82
Absolute Maximum Ratings .............................................. 117
ADCON0 Register............................................................... 13
ADCON1 Register............................................................... 14
ADRESH Registers ............................................................. 13
ADRESL Register ............................................................... 14
Analog-to-Digital Converter. See A/D.
Application Notes
AN552 (Implementing Wake-up on Key Stroke) ......... 35
AN556 (Implementing a Table Read) ......................... 24
Assembler
MPASM Assembler................................................... 111
Asynchronous Reception
Associated Registers .................................................. 69
Asynchronous Reception (9-bit Mode)
Associated Registers .................................................. 71
B
Banking, Data Memory ....................................................... 11
Baud Rate Generator (BRG)
Associated Registers .................................................. 63
Block Diagrams
A/D .............................................................................. 81
Analog Input Model ..................................................... 82
Capture Mode Operation ............................................ 56
Compare Mode Operation .......................................... 57
Interrupt Logic ............................................................. 97
On-Chip RESET Circuit .............................................. 91
PIC16F870.................................................................... 5
PIC16F871.................................................................... 6
PORTC (Peripheral Output Override) ......................... 37
PORTD (In I/O Port Mode).......................................... 38
PORTD and PORTE (Parallel Slave Port) .................. 42
PORTE (In I/O Port Mode).......................................... 39
PWM Mode ................................................................. 58
RA3:RA0 and RA5 Pins .............................................. 33
RA4/T0CKI Pin............................................................ 33
RB3:RB0 Pins ............................................................. 35
RB7:RB4 Pins ............................................................. 35
Timer0/WDT Prescaler ............................................... 45
 2003 Microchip Technology Inc.
Timer1 ........................................................................ 50
Timer2 ........................................................................ 53
USART Asynchronous Receive.................................. 68
USART Asynchronous Receive (9-bit Mode) ............. 70
USART Transmit ........................................................ 66
Watchdog Timer ......................................................... 99
BOR. See Brown-out Reset.
BRGH Bit ............................................................................ 63
Brown-out Reset (BOR).................................... 87, 91, 92, 93
BOR Status (BOR Bit) ................................................ 23
C
C Compilers
MPLAB C17.............................................................. 112
MPLAB C18.............................................................. 112
MPLAB C30.............................................................. 112
Capture/Compare/PWM (CCP) .......................................... 55
Associated Registers
Capture, Compare and Timer1........................... 59
PWM and Timer2................................................ 60
Capture Mode............................................................. 56
CCP1IF............................................................... 56
Prescaler ............................................................ 56
CCP Timer Resources................................................ 55
Compare
Special Trigger Output of CCP1 ......................... 57
Compare Mode........................................................... 57
Software Interrupt Mode ..................................... 57
Special Event Trigger ......................................... 57
PWM Mode................................................................. 58
Duty Cycle .......................................................... 58
Example Frequencies/Resolutions (table).......... 59
PWM Period ....................................................... 58
Setup for PWM Operation .................................. 59
Special Event Trigger and A/D Conversions .............. 57
CCP. See Capture/Compare/PWM.
CCP1CON Register............................................................ 13
CCP1M0 Bit ........................................................................ 55
CCP1M1 Bit ........................................................................ 55
CCP1M2 Bit ........................................................................ 55
CCP1M3 Bit ........................................................................ 55
CCP1X Bit .......................................................................... 55
CCP1Y Bit .......................................................................... 55
CCPR1H Register......................................................... 13, 55
CCPR1L Register ......................................................... 13, 55
Code Examples
Changing Between Capture Prescalers ..................... 56
EEPROM Data Read.................................................. 29
EEPROM Data Write .................................................. 29
FLASH Program Read................................................ 30
FLASH Program Write................................................ 31
Indirect Addressing..................................................... 24
Initializing PORTA ...................................................... 33
Saving STATUS, W and PCLATH Registers
in RAM................................................................ 98
Code Protected Operation
Data EEPROM and FLASH Program Memory ........... 31
Code Protection .......................................................... 87, 101
Computed GOTO................................................................ 24
Configuration Bits ............................................................... 87
Configuration Word............................................................. 88
Conversion Considerations............................................... 158
DS30569B-page 161
PIC16F870/871
D
Data EEPROM .................................................................... 27
Associated Registers .................................................. 32
Code Protection .......................................................... 31
Reading....................................................................... 29
Spurious Write Protection ........................................... 31
Write Verify ................................................................. 31
Writing to ..................................................................... 29
Data Memory....................................................................... 11
Bank Select (RP1:RP0 Bits) ....................................... 11
General Purpose Registers......................................... 11
Register File Map ........................................................ 12
Special Function Registers ......................................... 13
DC and AC Characteristics Graphs and Tables................ 137
DC Characteristics
PIC16F870/871 (Extended) ...................................... 123
PIC16F870/871 (Industrial) ....................................... 121
PIC16F870/871 (Industrial, Extended) and
PIC16LF870/871 (Commercial, Industrial)........ 119
Demonstration Boards
PICDEM 1 ................................................................. 114
PICDEM 17 ............................................................... 114
PICDEM 18R PIC18C601/801 .................................. 115
PICDEM 2 Plus ......................................................... 114
PICDEM 3 PIC16C92X ............................................. 114
PICDEM 4 ................................................................. 114
PICDEM LIN PIC16C43X ......................................... 115
PICDEM USB PIC16C7X5........................................ 115
PICDEM.net Internet/Ethernet .................................. 114
Development Support ....................................................... 111
Device Differences ............................................................ 157
Device Overview ................................................................... 5
Direct Addressing................................................................ 25
E
EEADR Register ................................................................. 15
EEADRH Register............................................................... 15
EECON1 Register ......................................................... 15, 27
EECON2 Register ......................................................... 15, 27
EEDATA Register ............................................................... 15
EEDATH Register ............................................................... 15
Electrical Characteristics................................................... 117
Errata .................................................................................... 4
Evaluation and Programming Tools .................................. 115
F
Firmware Instructions........................................................ 103
FLASH Program Memory.................................................... 27
Associated Registers .................................................. 32
Code Protection .......................................................... 31
Configuration Bits and Read/Write State .................... 32
Reading....................................................................... 30
Spurious Write Protection ........................................... 31
Write Protection .......................................................... 32
Write Verify ................................................................. 31
Writing to ..................................................................... 30
FSR Register........................................................... 13, 14, 15
I
Indirect Addressing ............................................................. 25
FSR Register ........................................................ 11, 24
INDF Register ............................................................. 24
Instruction Descriptions .................................................... 105
Instruction Format............................................................. 103
Instruction Set................................................................... 103
ADDLW..................................................................... 105
ADDWF..................................................................... 105
ANDLW..................................................................... 105
ANDWF..................................................................... 105
BCF .......................................................................... 105
BSF........................................................................... 105
BTFSC ...................................................................... 105
BTFSS ...................................................................... 105
CALL......................................................................... 106
CLRF ........................................................................ 106
CLRW ....................................................................... 106
CLRWDT .................................................................. 106
COMF ....................................................................... 106
DECF ........................................................................ 106
DECFSZ ................................................................... 107
GOTO ....................................................................... 107
INCF ......................................................................... 107
INCFSZ..................................................................... 107
IORLW ...................................................................... 107
IORWF...................................................................... 107
MOVF ....................................................................... 108
MOVLW .................................................................... 108
MOVWF .................................................................... 108
NOP .......................................................................... 108
RETFIE ..................................................................... 108
RETLW ..................................................................... 108
RETURN................................................................... 109
RLF ........................................................................... 109
RRF .......................................................................... 109
SLEEP ...................................................................... 109
SUBLW ..................................................................... 109
SUBWF..................................................................... 109
SWAPF ..................................................................... 110
XORLW .................................................................... 110
XORWF .................................................................... 110
Summary Table ........................................................ 104
INT Interrupt (RB0/INT). See Interrupt Sources.
INTCON .............................................................................. 15
INTCON Register.......................................................... 13, 15
GIE Bit ........................................................................ 18
INTE Bit ...................................................................... 18
INTF Bit ...................................................................... 18
PEIE Bit ...................................................................... 18
RBIE Bit ...................................................................... 18
RBIF Bit ................................................................ 18, 35
T0IE Bit ....................................................................... 18
Internal Sampling Switch (Rss) Impedance........................ 82
Interrupt Sources .......................................................... 87, 96
Interrupt-on-Change (RB7:RB4) ................................. 35
RB0/INT Pin, External................................................. 97
TMR0 Overflow........................................................... 97
USART Receive/Transmit Complete .......................... 61
Interrupts, Context Saving During....................................... 98
I/O Ports .............................................................................. 33
ID Locations ................................................................ 87, 101
In-Circuit Debugger ..................................................... 87, 101
In-Circuit Serial Programming (ICSP) ......................... 87, 102
INDF Register ......................................................... 13, 14, 15
DS30569B-page 162
 2003 Microchip Technology Inc.
PIC16F870/871
Interrupts, Enable Bits
Global Interrupt Enable (GIE Bit) .......................... 18, 96
Interrupt-on-Change (RB7:RB4) Enable
(RBIE Bit) ...................................................... 18, 97
Peripheral Interrupt Enable (PEIE Bit) ........................ 18
RB0/INT Enable (INTE Bit) ......................................... 18
TMR0 Overflow Enable (T0IE Bit)............................... 18
Interrupts, Flag Bits
Interrupt-on-Change (RB7:RB4)
Flag (RBIF Bit) ........................................ 18, 35, 97
RB0/INT Flag (INTF Bit).............................................. 18
TMR0 Overflow Flag (T0IF Bit) ................................... 97
L
Loading of PC ..................................................................... 24
Low Voltage In-Circuit Serial Programming ................ 87, 102
M
Master Clear (MCLR)
MCLR Reset, Normal Operation ........................... 91, 93
MCLR Reset, SLEEP............................................ 91, 93
MCLR/VPP/THV Pin .......................................................... 7, 8
Memory Organization
Data Memory .............................................................. 11
Program Memory ........................................................ 11
Migration from High-End to Enhanced Devices ................ 159
Migration from Mid-Range to Enhanced Devices ............. 158
MPLAB ASM30 Assembler, Linker, Librarian ................... 112
MPLAB ICD 2 In-Circuit Debugger ................................... 113
MPLAB ICE 2000 High Performance Universal
In-Circuit Emulator .................................................... 113
MPLAB ICE 4000 High Performance Universal
In-Circuit Emulator .................................................... 113
MPLAB Integrated Development
Environment Software............................................... 111
MPLINK Object Linker/MPLIB Object Librarian ................ 112
O
OPCODE Field Descriptions ............................................. 103
OPTION .............................................................................. 15
OPTION Register ................................................................ 15
OPTION_REG Register ................................................ 14, 17
INTEDG Bit ................................................................. 17
PSA Bit........................................................................ 17
RBPU Bit..................................................................... 17
T0CS Bit...................................................................... 17
T0SE Bit...................................................................... 17
OSC1/CLKI Pin ................................................................. 7, 8
OSC2/CLKO Pin ............................................................... 7, 8
Oscillator Configuration....................................................... 87
HS ......................................................................... 89, 92
LP.......................................................................... 89, 92
RC................................................................... 89, 90, 92
XT ......................................................................... 89, 92
Oscillator, WDT ................................................................... 99
Oscillators
Capacitor Selection..................................................... 90
Crystal and Ceramic Resonators ................................ 89
RC............................................................................... 90
 2003 Microchip Technology Inc.
P
Packaging ......................................................................... 149
Marking Information.................................................. 149
Parallel Slave Port (PSP).......................................... 9, 38, 42
Associated Registers.................................................. 43
RE0/RD/AN5 Pin .................................................. 41, 42
RE1/WR/AN6 Pin ................................................. 41, 42
RE2/CS/AN7 Pin .................................................. 41, 42
Select (PSPMODE Bit) ............................. 38, 39, 40, 42
PCL Register .................................................... 13, 14, 15, 24
PCLATH Register ............................................. 13, 14, 15, 24
PCON Register ....................................................... 14, 15, 92
BOR Bit....................................................................... 23
POR Bit....................................................................... 23
PICkit 1 FLASH Starter Kit................................................ 115
PICSTART Plus Development Programmer..................... 113
PIE1 Register ............................................................... 14, 15
PIE2 Register ............................................................... 14, 15
Pinout Descriptions
PIC16F870 ................................................................... 7
PIC16F871 ................................................................... 8
PIR1 Register ..................................................................... 13
PIR2 Register ..................................................................... 13
POP .................................................................................... 24
POR. See Power-on Reset.
PORTA ............................................................................. 7, 8
Associated Registers.................................................. 34
PORTA Register......................................................... 33
RA0/AN0 Pin ............................................................ 7, 8
RA1/AN1 Pin ............................................................ 7, 8
RA2/AN2/VREF- Pin ...................................................... 7
RA2/AN2/VREF- Pin ...................................................... 8
RA3/AN3/VREF+ Pin ..................................................... 7
RA3/AN3/VREF+ Pin ..................................................... 8
RA4/T0CKI Pin ......................................................... 7, 8
RA5/AN4 Pin ............................................................ 7, 8
TRISA Register........................................................... 33
PORTA Register ................................................................. 13
PORTB ............................................................................. 7, 8
PORTB Register......................................................... 35
Pull-up Enable (RBPU Bit).......................................... 17
RB0/INT Edge Select (INTEDG Bit) ........................... 17
RB0/INT Pin.............................................................. 7, 8
RB0/INT Pin, External ................................................ 97
RB1 Pin .................................................................... 7, 8
RB2 Pin .................................................................... 7, 8
RB3/PGM Pin ........................................................... 7, 8
RB4 Pin .................................................................... 7, 8
RB5 Pin .................................................................... 7, 8
RB6/PGC Pin............................................................ 7, 8
RB7/PGD Pin............................................................ 7, 8
RB7:RB4 Interrupt-on-Change ................................... 97
RB7:RB4 Interrupt-on-Change
Enable (RBIE Bit) ......................................... 18, 97
RB7:RB4 Interrupt-on-Change
Flag (RBIF Bit)........................................ 18, 35, 97
TRISB Register........................................................... 35
PORTB Register ........................................................... 13, 15
DS30569B-page 163
PIC16F870/871
PORTC.............................................................................. 7, 8
Associated Registers .................................................. 37
PORTC Register ......................................................... 37
RC0/T1OSO/T1CKI Pin ............................................ 7, 8
RC1/T1OSI Pin ......................................................... 7, 8
RC2/CCP1 Pin .......................................................... 7, 8
RC3 Pin..................................................................... 7, 8
RC4 Pin..................................................................... 7, 8
RC5 Pin..................................................................... 7, 8
RC6/TX/CK Pin ................................................... 7, 8, 62
RC7/RX/DT Pin ............................................. 7, 8, 62, 63
TRISC Register ..................................................... 37, 61
PORTC Register ................................................................. 13
PORTD............................................................................ 9, 42
Associated Registers .................................................. 38
Parallel Slave Port (PSP) Function ............................. 38
PORTD Register ......................................................... 38
RD0/PSP0 Pin .............................................................. 9
RD1/PSP1 Pin .............................................................. 9
RD2/PSP2 Pin .............................................................. 9
RD3/PSP3 Pin .............................................................. 9
RD4/PSP4 Pin .............................................................. 9
RD5/PSP5 Pin .............................................................. 9
RD6/PSP6 Pin .............................................................. 9
RD7/PSP7 Pin .............................................................. 9
TRISD Register ........................................................... 38
PORTD Register ................................................................. 13
PORTE.................................................................................. 9
Analog Port Pins ................................................... 41, 42
Associated Registers .................................................. 41
Input Buffer Full Status (IBF Bit) ................................. 40
Input Buffer Overflow (IBOV Bit) ................................. 40
Output Buffer Full Status (OBF Bit)............................. 40
PORTE Register ......................................................... 39
PSP Mode Select (PSPMODE Bit) ........... 38, 39, 40, 42
RE0/RD/AN5 Pin............................................... 9, 41, 42
RE1/WR/AN6 Pin .............................................. 9, 41, 42
RE2/CS/AN7 Pin............................................... 9, 41, 42
TRISE Register ........................................................... 39
PORTE Register ................................................................. 13
Postscaler, WDT
Assignment (PSA Bit) ................................................. 17
Power-down Mode. See SLEEP.
Power-on Reset (POR) ..................................... 87, 91, 92, 93
Oscillator Start-up Timer (OST) ............................ 87, 92
POR Status (POR Bit)................................................. 23
Power Control (PCON) Register ................................. 92
Power-down (PD Bit) .................................................. 91
Power-up Timer (PWRT) ...................................... 87, 92
Time-out (TO Bit) ........................................................ 91
PR2 ..................................................................................... 15
PR2 Register................................................................. 14, 53
Prescaler, Timer0
Assignment (PSA Bit) ................................................. 17
PRO MATE II Universal Device Programmer ................... 113
Product Identification System............................................ 169
Program Counter
RESET Conditions ...................................................... 93
Program Memory ................................................................ 11
Interrupt Vector ........................................................... 11
Map and Stack ............................................................ 11
Paging ......................................................................... 24
RESET Vector............................................................. 11
Program Verification.......................................................... 101
Programming, Device Instructions .................................... 103
DS30569B-page 164
Pulse Width Modulation.
See Capture/Compare/PWM, PWM Mode.
PUSH.................................................................................. 24
R
RAM. See Data Memory.
RCREG Register ................................................................ 13
RCSTA Register ................................................................. 13
ADDEN Bit .................................................................. 62
CREN Bit .................................................................... 62
FERR Bit..................................................................... 62
OERR Bit .................................................................... 62
RX9 Bit ....................................................................... 62
RX9D Bit ..................................................................... 62
SPEN Bit............................................................... 61, 62
SREN Bit .................................................................... 62
Register File........................................................................ 11
Register File Map................................................................ 12
Registers
ADCON0 (A/D Control 0)............................................ 79
ADCON1 (A/D Control 1)............................................ 80
CCP1CON (CCP Control 1)........................................ 55
EECON1 (EEPROM Control 1) .................................. 28
INTCON ...................................................................... 18
OPTION_REG ...................................................... 17, 46
PCON (Power Control) ............................................... 23
PIE1 (Peripheral Interrupt Enable 1)........................... 19
PIE2 (Peripheral Interrupt Enable 2)........................... 21
PIR1 (Peripheral Interrupt Request Flag 1) ................ 20
PIR2 (Peripheral Interrupt Request Flag 2) ................ 22
RCSTA (Receive Status and Control) ........................ 62
STATUS ..................................................................... 16
T1CON (Timer1 Control) ............................................ 49
T2CON (Timer 2 Control) ........................................... 53
TRISE ......................................................................... 40
TXSTA (Transmit Status and Control) ........................ 61
Reset ............................................................................ 87, 91
MCLR Reset. See MCLR.
RESET Conditions for All Registers ........................... 93
RESET Conditions for PCON Register....................... 93
RESET Conditions for Program Counter .................... 93
RESET Conditions for STATUS Register ................... 93
Reset
Brown-out Reset (BOR). See Brown-out Reset (BOR).
Power-on Reset (POR). See Power-on Reset (POR).
WDT Reset. See Watchdog Timer (WDT).
Revision History................................................................ 157
S
SCI. See USART
Serial Communication Interface. See USART.
SLEEP .................................................................. 87, 91, 100
Software Simulator (MPLAB SIM) .................................... 112
Software Simulator (MPLAB SIM30) ................................ 112
SPBRG ............................................................................... 15
SPBRG Register................................................................. 14
Special Features of the CPU .............................................. 87
Special Function Registers ................................................. 13
Special Function Register Summary .......................... 13
Speed, Operating.................................................................. 1
SSPADD Register............................................................... 15
SSPSTAT Register ............................................................. 15
Stack................................................................................... 24
Overflows.................................................................... 24
Underflow ................................................................... 24
 2003 Microchip Technology Inc.
PIC16F870/871
STATUS Register ......................................................... 13, 15
PD Bit.......................................................................... 91
TO Bit.......................................................................... 91
Synchronous Master Reception
Associated Registers .................................................. 75
Synchronous Master Transmission
Associated Registers .................................................. 73
Synchronous Slave Reception
Associated Registers .................................................. 77
Synchronous Slave Transmission
Associated Registers .................................................. 76
T
T1CKPS0 Bit ....................................................................... 49
T1CKPS1 Bit ....................................................................... 49
T1CON Register ................................................................. 13
T1OSCEN Bit ...................................................................... 49
T1SYNC Bit......................................................................... 49
T2CKPS0 Bit ....................................................................... 53
T2CKPS1 Bit ....................................................................... 53
T2CON Register ................................................................. 13
TAD ...................................................................................... 83
Time-out Sequence............................................................. 92
Timer0 ................................................................................. 45
Associated Registers .................................................. 47
Clock Source Edge Select (T0SE Bit)......................... 17
Clock Source Select (T0CS Bit).................................. 17
External Clock............................................................. 46
Interrupt....................................................................... 45
Overflow Enable (T0IE Bit) ......................................... 18
Overflow Flag (T0IF Bit).............................................. 97
Overflow Interrupt ....................................................... 97
Prescaler..................................................................... 46
T0CKI.......................................................................... 46
Timer1 ................................................................................. 49
Associated Registers .................................................. 52
Asynchronous Counter Mode
Reading and Writing to ....................................... 51
Counter Operation ...................................................... 50
Incrementing Edge (figure) ......................................... 50
Operation in Asynchronous Counter Mode................. 51
Operation in Synchronized Counter Mode.................. 50
Operation in Timer Mode ............................................ 50
Oscillator ..................................................................... 51
Capacitor Selection............................................. 51
Prescaler..................................................................... 52
Resetting of Timer1 Register Pair
(TMR1H, TMR1L) ............................................... 52
Resetting Timer1 Using a CCP Trigger Output........... 51
TMR1H........................................................................ 51
TMR1L ........................................................................ 51
Timer2 ................................................................................. 53
Associated Registers .................................................. 54
Output ......................................................................... 54
Postscaler ................................................................... 53
Prescaler..................................................................... 53
Prescaler and Postscaler ............................................ 54
Timing Diagrams
A/D Conversion......................................................... 135
Asynchronous Master Transmission........................... 67
Asynchronous Master Transmission
(Back to Back) .................................................... 67
Asynchronous Reception with
Address Byte First .............................................. 71
 2003 Microchip Technology Inc.
Asynchronous Reception with
Address Detect ................................................... 71
Brown-out Reset....................................................... 129
Capture/Compare/PWM (CCP1) .............................. 131
CLKO and I/O ........................................................... 128
External Clock .......................................................... 126
Parallel Slave Port (PSP) Read.................................. 43
Parallel Slave Port (PSP) Write .................................. 43
RESET, Watchdog Timer, Oscillator
Start-up Timer and Power-up Timer ................. 129
Slow Rise Time (MCLR Tied to VDD) ......................... 96
Time-out Sequence on Power-up
(MCLR Not Tied to VDD)
Case 1 ................................................................ 95
Case 2 ................................................................ 95
Time-out Sequence on Power-up
(MCLR Tied to VDD) ........................................... 95
Timer0 and Timer1 External Clock ........................... 130
USART Asynchronous Reception .............................. 68
USART Synchronous Receive (Master/Slave) ......... 133
USART Synchronous Reception
(Master Mode, SREN) ........................................ 75
USART Synchronous Transmission ........................... 73
USART Synchronous Transmission
(Master/Slave) .................................................. 133
Wake-up from SLEEP via Interrupt .......................... 101
Timing Parameter Symbology .......................................... 125
TMR0 Register.............................................................. 13, 15
TMR1CS Bit........................................................................ 49
TMR1H Register ................................................................. 13
TMR1L Register.................................................................. 13
TMR1ON Bit ....................................................................... 49
TMR2 Register.................................................................... 13
TMR2ON Bit ....................................................................... 53
TOUTPS0 Bit ...................................................................... 53
TOUTPS1 Bit ...................................................................... 53
TOUTPS2 Bit ...................................................................... 53
TOUTPS3 Bit ...................................................................... 53
TRISA ................................................................................. 15
TRISA Register................................................................... 14
TRISB ................................................................................. 15
TRISB Register............................................................. 14, 15
TRISC ................................................................................. 15
TRISC Register................................................................... 14
TRISD ................................................................................. 15
TRISD Register................................................................... 14
TRISE ................................................................................. 15
TRISE Register................................................................... 14
IBF Bit......................................................................... 40
IBOV Bit...................................................................... 40
OBF Bit ....................................................................... 40
PSPMODE Bit .......................................... 38, 39, 40, 42
TXREG Register ................................................................. 13
TXSTA ................................................................................ 15
TXSTA Register.................................................................. 14
BRGH Bit .................................................................... 61
CSRC Bit .................................................................... 61
TRMT Bit .................................................................... 61
TX9 Bit........................................................................ 61
TX9D Bit ..................................................................... 61
TXEN Bit ..................................................................... 61
DS30569B-page 165
PIC16F870/871
U
W
Universal Synchronous Asynchronous Receiver Transmitter.
See USART
USART ................................................................................ 61
Address Detect Enable (ADDEN Bit) .......................... 62
Asynchronous Mode ................................................... 66
Asynchronous Receive ............................................... 68
Asynchronous Receive (9-bit Mode) ........................... 70
Asynchronous Receive with Address Detect.
See Asynchronous Receive (9-bit Mode).
Asynchronous Reception ............................................ 69
Asynchronous Transmitter .......................................... 66
Baud Rate Generator (BRG)....................................... 63
Baud Rate Formula............................................. 63
Baud Rates, Asynchronous Mode
(BRGH = 0) ................................................. 64
Baud Rates, Asynchronous Mode
(BRGH = 1) ................................................. 65
High Baud Rate Select (BRGH Bit)..................... 61
Sampling ............................................................. 63
Clock Source Select (CSRC Bit) ................................. 61
Continuous Receive Enable (CREN Bit) ..................... 62
Framing Error (FERR Bit) ........................................... 62
Overrun Error (OERR Bit) ........................................... 62
Receive Data, 9th bit (RX9D Bit) ................................ 62
Receive Enable, 9-bit (RX9 Bit) .................................. 62
Serial Port Enable (SPEN Bit)............................... 61, 62
Single Receive Enable (SREN Bit) ............................. 62
Synchronous Master Mode ......................................... 72
Synchronous Master Reception .................................. 74
Synchronous Master Transmission............................. 72
Synchronous Slave Mode ........................................... 76
Synchronous Slave Reception .................................... 77
Synchronous Slave Transmit ...................................... 76
Transmit Data, 9th Bit (TX9D)..................................... 61
Transmit Enable (TXEN Bit)........................................ 61
Transmit Enable, Nine-bit (TX9 Bit) ............................ 61
Transmit Shift Register Status (TRMT Bit).................. 61
Wake-up from SLEEP................................................. 87, 100
Interrupts .................................................................... 93
MCLR Reset ............................................................... 93
Timing Diagram ........................................................ 101
WDT Reset ................................................................. 93
Watchdog Timer
Register Summary ...................................................... 99
Watchdog Timer (WDT)................................................ 87, 99
Enable (WDTEN Bit)................................................... 99
Postscaler. See Postscaler, WDT.
Programming Considerations ..................................... 99
RC Oscillator............................................................... 99
Time-out Period .......................................................... 99
WDT Reset, Normal Operation............................. 91, 93
WDT Reset, SLEEP.............................................. 91, 93
Write Verify
Data EEPROM and FLASH Program Memory ........... 31
WWW, On-Line Support ....................................................... 4
DS30569B-page 166
 2003 Microchip Technology Inc.
PIC16F870/871
ON-LINE SUPPORT
Microchip provides on-line support on the Microchip
World Wide Web site.
The web site is used by Microchip as a means to make
files and information easily available to customers. To
view the site, the user must have access to the Internet
and a web browser, such as Netscape® or Microsoft®
Internet Explorer. Files are also available for FTP
download from our FTP site.
Connecting to the Microchip Internet
Web Site
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 the most current upgrade kits.The Hot Line
Numbers are:
1-800-755-2345 for U.S. and most of Canada, and
1-480-792-7302 for the rest of the world.
042003
The Microchip web site is available at the following
URL:
www.microchip.com
The file transfer site is available by using an FTP service to connect to:
ftp://ftp.microchip.com
The web site and file transfer site provide a variety of
services. Users may download files for the latest
Development Tools, Data Sheets, Application Notes,
User's Guides, Articles and Sample Programs. A variety 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, Development Systems,
technical information and more
• Listing of seminars and events
 2003 Microchip Technology Inc.
DS30569B-page 167
PIC16F870/871
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150.
Please list the following information, and use this outline to provide us with your comments about this document.
To:
Technical Publications Manager
RE:
Reader Response
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Address
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Telephone: (_______) _________ - _________
FAX: (______) _________ - _________
Application (optional):
Would you like a reply?
Device: PIC16F870/871
Y
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Literature Number: DS30569B
Questions:
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 document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
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6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
DS30569B-page 168
 2003 Microchip Technology Inc.
PIC16F870/871
PIC16F870/871 PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
-X
/XX
XXX
Device
Temperature
Range
Package
Pattern
Examples:
a)
b)
Device
PIC16F870, PIC16F870T; VDD range 4.0V to 5.5V
PIC16F871, PIC16F871T ; VDD range 4.0V to 5.5V
PIC16LF870X, PIC16LF870T; VDD range 2.0V to 5.5V
PIC16LF871X, PIC16LF871T; VDD range 2.0V to 5.5V
F
LP
T
=
=
=
Normal VDD limits
Extended VDD limits
In Tape and Reel - SOIC, SSOP, TQFP and
PLCC packages only.
Temperature Range
blank(3) =
I
=
Package
PQ
PT
SO
SP
SS
P
L
Pattern
QTP, Code or Special Requirements
(blank otherwise)
=
=
=
=
=
=
=
c)
d)
PIC16F870-I/SP 301 = Industrial temp., PDIP
package, 20 MHz, normal VDD limits, QTP
pattern #301.
PIC16F871-I/PT = Industrial temp., TQFP
package, 20 MHz, Extended VDD limits.
PIC16F871-I/P = Industrial temp., PDIP
package, 20 MHz, normal VDD limits.
PIC16LF870-I/SS = Industrial temp., SSOP
package, DC - 20 MHz, extended VDD limits.
0°C to +70°C (Commercial)
-40°C to +85°C (Industrial)
MQFP (Metric PQFP)
TQFP (Thin Quad Flatpack)
SOIC
Skinny Plastic Dip
SSOP
PDIP
PLCC
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may 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:
1.
2.
3.
Your local Microchip sales office
The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277
The Microchip Worldwide Site (www.microchip.com)
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
New Customer Notification System
Register on our web site (www.microchip.com/cn) to receive the most current information on our products.
 2003 Microchip Technology Inc.
DS30569B-page 169
WORLDWIDE SALES AND SERVICE
AMERICAS
ASIA/PACIFIC
Japan
Corporate Office
Australia
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200 Fax: 480-792-7277
Technical Support: 480-792-7627
Web Address: http://www.microchip.com
Microchip Technology Australia Pty Ltd
Marketing Support Division
Suite 22, 41 Rawson Street
Epping 2121, NSW
Australia
Tel: 61-2-9868-6733 Fax: 61-2-9868-6755
Microchip Technology Japan K.K.
Benex S-1 6F
3-18-20, Shinyokohama
Kohoku-Ku, Yokohama-shi
Kanagawa, 222-0033, Japan
Tel: 81-45-471- 6166 Fax: 81-45-471-6122
Atlanta
3780 Mansell Road, Suite 130
Alpharetta, GA 30022
Tel: 770-640-0034 Fax: 770-640-0307
China - Beijing
2 Lan Drive, Suite 120
Westford, MA 01886
Tel: 978-692-3848 Fax: 978-692-3821
Microchip Technology Consulting (Shanghai)
Co., Ltd., Beijing Liaison Office
Unit 915
Bei Hai Wan Tai Bldg.
No. 6 Chaoyangmen Beidajie
Beijing, 100027, No. China
Tel: 86-10-85282100 Fax: 86-10-85282104
Chicago
China - Chengdu
333 Pierce Road, Suite 180
Itasca, IL 60143
Tel: 630-285-0071 Fax: 630-285-0075
Microchip Technology Consulting (Shanghai)
Co., Ltd., Chengdu Liaison Office
Rm. 2401-2402, 24th Floor,
Ming Xing Financial Tower
No. 88 TIDU Street
Chengdu 610016, China
Tel: 86-28-86766200 Fax: 86-28-86766599
Boston
Dallas
4570 Westgrove Drive, Suite 160
Addison, TX 75001
Tel: 972-818-7423 Fax: 972-818-2924
Detroit
Tri-Atria Office Building
32255 Northwestern Highway, Suite 190
Farmington Hills, MI 48334
Tel: 248-538-2250 Fax: 248-538-2260
Kokomo
2767 S. Albright Road
Kokomo, IN 46902
Tel: 765-864-8360 Fax: 765-864-8387
Los Angeles
18201 Von Karman, Suite 1090
Irvine, CA 92612
Tel: 949-263-1888 Fax: 949-263-1338
Phoenix
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7966 Fax: 480-792-4338
San Jose
Microchip Technology Inc.
2107 North First Street, Suite 590
San Jose, CA 95131
Tel: 408-436-7950 Fax: 408-436-7955
Toronto
6285 Northam Drive, Suite 108
Mississauga, Ontario L4V 1X5, Canada
Tel: 905-673-0699 Fax: 905-673-6509
China - Fuzhou
Microchip Technology Consulting (Shanghai)
Co., Ltd., Fuzhou Liaison Office
Unit 28F, World Trade Plaza
No. 71 Wusi Road
Fuzhou 350001, China
Tel: 86-591-7503506 Fax: 86-591-7503521
China - Hong Kong SAR
Microchip Technology Hongkong Ltd.
Unit 901-6, Tower 2, Metroplaza
223 Hing Fong Road
Kwai Fong, N.T., Hong Kong
Tel: 852-2401-1200 Fax: 852-2401-3431
China - Shanghai
Microchip Technology Consulting (Shanghai)
Co., Ltd.
Room 701, Bldg. B
Far East International Plaza
No. 317 Xian Xia Road
Shanghai, 200051
Tel: 86-21-6275-5700 Fax: 86-21-6275-5060
China - Shenzhen
Microchip Technology Consulting (Shanghai)
Co., Ltd., Shenzhen Liaison Office
Rm. 1812, 18/F, Building A, United Plaza
No. 5022 Binhe Road, Futian District
Shenzhen 518033, China
Tel: 86-755-82901380 Fax: 86-755-82966626
China - Qingdao
Rm. B505A, Fullhope Plaza,
No. 12 Hong Kong Central Rd.
Qingdao 266071, China
Tel: 86-532-5027355 Fax: 86-532-5027205
India
Microchip Technology Inc.
India Liaison Office
Marketing Support Division
Divyasree Chambers
1 Floor, Wing A (A3/A4)
No. 11, O’Shaugnessey Road
Bangalore, 560 025, India
Tel: 91-80-2290061 Fax: 91-80-2290062
Korea
Microchip Technology Korea
168-1, Youngbo Bldg. 3 Floor
Samsung-Dong, Kangnam-Ku
Seoul, Korea 135-882
Tel: 82-2-554-7200 Fax: 82-2-558-5934
Singapore
Microchip Technology Singapore Pte Ltd.
200 Middle Road
#07-02 Prime Centre
Singapore, 188980
Tel: 65-6334-8870 Fax: 65-6334-8850
Taiwan
Microchip Technology (Barbados) Inc.,
Taiwan Branch
11F-3, No. 207
Tung Hua North Road
Taipei, 105, Taiwan
Tel: 886-2-2717-7175 Fax: 886-2-2545-0139
EUROPE
Austria
Microchip Technology Austria GmbH
Durisolstrasse 2
A-4600 Wels
Austria
Tel: 43-7242-2244-399
Fax: 43-7242-2244-393
Denmark
Microchip Technology Nordic ApS
Regus Business Centre
Lautrup hoj 1-3
Ballerup DK-2750 Denmark
Tel: 45-4420-9895 Fax: 45-4420-9910
France
Microchip Technology SARL
Parc d’Activite du Moulin de Massy
43 Rue du Saule Trapu
Batiment A - ler Etage
91300 Massy, France
Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79
Germany
Microchip Technology GmbH
Steinheilstrasse 10
D-85737 Ismaning, Germany
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Italy
Microchip Technology SRL
Via Quasimodo, 12
20025 Legnano (MI)
Milan, Italy
Tel: 39-0331-742611 Fax: 39-0331-466781
United Kingdom
Microchip Ltd.
505 Eskdale Road
Winnersh Triangle
Wokingham
Berkshire, England RG41 5TU
Tel: 44-118-921-5869 Fax: 44-118-921-5820
03/25/03
DS30569B-page 170
 2003 Microchip Technology Inc.
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