PIC16F7x Datasheet by Microchip Technology

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2002 Microchip Technology Inc. DS30325B
PIC16F7X
Data Sheet
28/40-pin, 8-bit CMOS FLASH
Microcontrollers
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DS30325B - page ii 2002 Microchip Technology Inc.
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and may be superseded by updates.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
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical com-
ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con-
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rights.
Trademarks
The Microchip name and logo, the Microchip logo, FilterLab,
KEELOQ, MPLAB, PIC, PICmicro, PICMASTER, PICSTART,
PRO MATE, SEEVAL and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, microID,
microPort, Migratable Memory, MPASM, MPLIB, MPLINK,
MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select
Mode and Total Endurance are trademarks of Microchip
Technology Incorporated in the U.S.A.
Serialized Quick Term 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.
© 2002, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999. The
Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro® 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs and microperipheral
products. In addition, Microchips quality
system for the design and manufacture of
development systems is ISO 9001 certified.
Note the following details of the code protection feature on PICmicro® MCUs.
The PICmicro family meets the specifications contained in the Microchip Data Sheet.
Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today,
when used in the intended manner and under normal conditions.
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowl-
edge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet.
The person doing so may be engaged in theft of intellectual property.
Microchip is willing to work with the customer who is concerned about the integrity of their code.
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as unbreakable.
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of
our product.
If you have any further questions about this matter, please contact the local sales office nearest to you.
Q ‘MICROCHIP P|C1 6F7X
2002 Microchip Technology Inc. DS30325B-page 1
MPIC16F7X
Devices Included in this Data Sheet:
High Performance RISC CPU:
High performance RISC CPU
Only 35 single word instructions to learn
All single cycle instructions except for program
branches which are two-cycle
Operating speed: DC - 20 MHz clock input
DC - 200 ns instruction cycle
Up to 8K x 14 words of FLASH Program Memory,
Up to 368 x 8 bytes of Data Memory (RAM)
Pinout compatible to the PIC16C73B/74B/76/77
Pinout compatible to the PIC16F873/874/876/877
Interrupt capability (up to 12 sources)
Eight level deep hardware stack
Direct, Indirect and Relative Addressing modes
Processor read access to program memory
Special Microcontroller Features:
Power-on Reset (POR)
Power-up Timer (PWRT) and
Oscillator Start-up Timer (OST)
Watchdog Timer (WDT) with its own on-chip RC
oscillator for reliable operation
Programmable code protection
Power saving SLEEP mode
Selectable oscillator options
In-Circuit Serial Programming(ICSP) via two
pins
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
Two Capture, Compare, PWM modules
- 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
8-bit, up to 8-channel Analog-to-Digital converter
Synchronous Serial Port (SSP) with SPI (Master
mode) and I2C (Slave)
Universal Synchronous Asynchronous Receiver
Transmitter (USART/SCI)
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)
CMOS Technology:
Low power, high speed CMOS FLASH technology
Fully static design
Wide operating voltage range: 2.0V to 5.5V
High Sink/Source Current: 25 mA
Industrial temperature range
Low power consumption:
- < 2 mA typical @ 5V, 4 MHz
-20 µA typical @ 3V, 32 kHz
-< 1 µA typical standby current
PIC16F73
PIC16F74
PIC16F76
PIC16F77
Device Program Memory
(# Single Word
Instructions)
Data
SRAM
(Bytes) I/O Interrupts 8-bit
A/D (ch) CCP
(PWM)
SSP
USART Timers
8/16-bit
SPI
(Master) I2C
(Slave)
PIC16F73 4096 192 22 11 5 2 Yes Yes Yes 2 / 1
PIC16F74 4096 192 33 12 8 2 Yes Yes Yes 2 / 1
PIC16F76 8192 368 22 11 5 2 Yes Yes Yes 2 / 1
PIC16F77 8192 368 33 12 8 2 Yes Yes Yes 2 / 1
28/40-Pin 8-Bit CMOS FLASH Microcontrollers
HHIII
PIC16F7X
DS30325B-page 2 2002 Microchip Technology Inc.
Pin Diagrams
PIC16F76/73
10
11
2
3
4
5
6
1
8
7
9
12
13
14 15
16
17
18
19
20
23
24
25
26
27
28
22
21
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2
RA3/AN3/VREF
RA4/T0CKI
RA5/AN4/SS
VSS
OSC1/CLKIN
OSC2/CLKOUT
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RB7/PGD
RB6/PGC
RB5
RB4
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
DIP, SOIC, SSOP
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/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2
RA3/AN3/VREF
RA4/T0CKI
RA5/AN4/SS
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKIN
OSC2/CLKOUT
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
PIC16F77/74
PDIP
2
3
4
5
6
1
7
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2
RA3/AN3/VREF
RA4/T0CKI
RA5/AN4/SS
15
16
17
18
19
20
21
RB0/INT
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
VSS
OSC1/CLKI
OSC2/CLKO
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
23
24
25
26
27
28 22
RB7/PGD
RB6/PGC
RB5
RB4
RB3/PGM
RB2
RB1
10 11
8912
13 14
MLF
PIC16F73
PIC16F76
fig
2002 Microchip Technology Inc. DS30325B-page 3
PIC16F7X
Pin Diagrams (Continued)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
44
8
7
6
5
4
3
2
1
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
9
PIC16F77
RA4/T0CKI
RA5/AN4/SS
RE0/RD/AN5
OSC1/CLKIN
OSC2/CLKOUT
RC0/T1OSO/T1CK1
NC
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC7/RX/DT
RA3/AN3/VREF
RA2/AN2
RA1/AN1
RA0/AN0
MCLR/VPP
NC
RB7/PGD
RB6/PGC
RB5
RB4
NC
NC
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1
RC1/T1OSI/CCP2
10
11
2
3
4
5
6
1
18
19
20
21
22
12
13
14
15
38
8
7
44
43
42
41
40
39
16
17
29
30
31
32
33
23
24
25
26
27
28
36
34
35
9
PIC16F77
37
RA3/AN3/VREF
RA2/AN2
RA1/AN1
RA0/AN0
MCLR/VPP
NC
RB7/PGD
RB6/PGC
RB5
RB4
NC RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1
RC1/T1OSI/CCP2
NC
NC
RC0/T1OSO/T1CKI
OSC2/CLKOUT
OSC1/CLKIN
VSS
VDD
RE2/AN7/CS
RE1/AN6/WR
RE0/AN5/RD
RA5/AN4/SS
RA4/T0CKI
RC7/RX/DT
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
VSS
VDD
RB0/INT
RB1
RB2
RB3/PGM
PLCC
QFP
PIC16F74
PIC16F74
PIC16F7X
DS30325B-page 4 2002 Microchip Technology Inc.
Table of Contents
1.0 Device Overview......................................................................................................................................................................... 5
2.0 Memory Organization................................................................................................................................................................ 13
3.0 Reading Program Memory........................................................................................................................................................ 29
4.0 I/O Ports.................................................................................................................................................................................... 31
5.0 Timer0 Module.......................................................................................................................................................................... 43
6.0 Timer1 Module.......................................................................................................................................................................... 47
7.0 Timer2 Module.......................................................................................................................................................................... 51
8.0 Capture/Compare/PWM Modules............................................................................................................................................. 53
9.0 Synchronous Serial Port (SSP) Module.................................................................................................................................... 59
10.0 Universal Synchronous Asynchronous Receiver Transmitter (USART) ................................................................................... 69
11.0 Analog-to-Digital Converter (A/D) Module ................................................................................................................................ 83
12.0 Special Features of the CPU .................................................................................................................................................... 89
13.0 Instruction Set Summary......................................................................................................................................................... 105
14.0 Development Support ............................................................................................................................................................. 113
15.0 Electrical Characteristics......................................................................................................................................................... 119
16.0 DC and AC Characteristics Graphs and Tables ..................................................................................................................... 141
17.0 Packaging Information ............................................................................................................................................................ 151
Appendix A: Revision History ........................................................................................................................................................ 161
Appendix B: Device Differences .................................................................................................................................................... 161
Appendix C: Conversion Considerations ....................................................................................................................................... 162
Index ................................................................................................................................................................................................. 163
On-Line Support................................................................................................................................................................................ 169
Reader Response ............................................................................................................................................................................. 170
PIC16F7X Product Identification System .......................................................................................................................................... 171
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2002 Microchip Technology Inc. DS30325B-page 5
PIC16F7X
1.0 DEVICE OVERVIEW
This document contains device specific information
about the following devices:
PIC16F73
PIC16F74
PIC16F76
PIC16F77
PIC16F73/76 devices are available only in 28-pin pack-
ages, while PIC16F74/77 devices are available in
40-pin and 44-pin packages. All devices in the
PIC16F7X family share common architecture, with the
following differences:
The PIC16F73 and PIC16F76 have one-half of
the total on-chip memory of the PIC16F74 and
PIC16F77
The 28-pin devices have 3 I/O ports, while the
40/44-pin devices have 5
The 28-pin devices have 11 interrupts, while the
40/44-pin devices have 12
The 28-pin devices have 5 A/D input channels,
while the 40/44-pin devices have 8
The Parallel Slave Port is implemented only on
the 40/44-pin devices
The available features are summarized in Table 1-1.
Block diagrams of the PIC16F73/76 and PIC16F74/77
devices are provided in Figure 1-1 and Figure 1-2,
respectively. The pinouts for these device families are
listed in Table 1-2 and Table 1-3.
Additional information may be found in the PICmicro
Mid-Range Reference Manual (DS33023), which may
be obtained from your local Microchip Sales Represen-
tative or downloaded from the Microchip website. The
Reference Manual should be considered a complemen-
tary document to this data sheet, and is highly recom-
mended reading for a better understanding of the device
architecture and operation of the peripheral modules.
TABLE 1-1: PIC16F7X DEVICE FEATURES
Key Features PIC16F73 PIC16F74 PIC16F76 PIC16F77
Operating Frequency DC - 20 MHz DC - 20 MHz DC - 20 MHz DC - 20 MHz
RESETS (and Delays) POR, BOR
(PWRT, OST) POR, BOR
(PWRT, OST) POR, BOR
(PWRT, OST) POR, BOR
(PWRT, OST)
FLASH Program Memory
(14-bit words) 4K 4K 8K 8K
Data Memory (bytes) 192 192 368 368
Interrupts 11 12 11 12
I/O Ports Ports A,B,C Ports A,B,C,D,E Ports A,B,C Ports A,B,C,D,E
Timers 3333
Capture/Compare/PWM Modules 2 2 2 2
Serial Communications SSP, USART SSP, USART SSP, USART SSP, USART
Parallel Communications PSP PSP
8-bit Analog-to-Digital Module 5 Input Channels 8 Input Channels 5 Input Channels 8 Input Channels
Instruction Set 35 Instructions 35 Instructions 35 Instructions 35 Instructions
Packaging 28-pin DIP
28-pin SOIC
28-pin SSOP
28-pin MLF
40-pin PDIP
44-pin PLCC
44-pin TQFP
28-pin DIP
28-pin SOIC
28-pin SSOP
28-pin MLF
40-pin PDIP
44-pin PLCC
44-pin TQFP
fr 1? fl} M, H H
PIC16F7X
DS30325B-page 6 2002 Microchip Technology Inc.
FIGURE 1-1: PIC16F73 AND PIC16F76 BLOCK DIAGRAM
FLASH
Program
Memory
13 Data Bus 8
14
Program
Bus
Instruction reg
Program Counter
8 Level Stack
(13-bit)
RAM
File
Registers
Direct Addr 7
RAM Addr(1) 9
Addr MUX
Indirect
Addr
FSR reg
STATUS reg
MUX
ALU
W reg
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKIN
OSC2/CLKOUT
MCLR VDD, VSS
PORTA
PORTB
PORTC
RA4/T0CKI
RA5/AN4/SS
RB0/INT
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
8
8
Brown-out
Reset
Note 1: Higher order bits are from the STATUS register.
USART
CCP2 Synchronous
8-bit A/DTimer0 Timer1 Timer2
Serial Port
RA3/AN3/VREF
RA2/AN2/
RA1/AN1
RA0/AN0
8
3
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
Device Program FLASH Data Memory
PIC16F73 4K 192 Bytes
PIC16F76 8K 368 Bytes
CCP1
L A H ‘. WWWW JL XXX \
2002 Microchip Technology Inc. DS30325B-page 7
PIC16F7X
FIGURE 1-2: PIC16F74 AND PIC16F77 BLOCK DIAGRAM
FLASH
Program
Memory
13 Data Bus 8
14
Program
Bus
Instruction reg
Program Counter
8 Level Stack
(13-bit)
RAM
File
Registers
Direct Addr 7
RAM Addr(1) 9
Addr MUX
Indirect
Addr
FSR reg
STATUS reg
MUX
ALU
W reg
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKIN
OSC2/CLKOUT
MCLR VDD, VSS
PORTA
PORTB
PORTC
PORTD
PORTE
RA4/T0CKI
RA5/AN4/SS
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
RE0/AN5/RD
RE1/AN6/WR
RE2/AN7/CS
8
8
Brown-out
Reset
Note 1: Higher order bits are from the STATUS register.
USART
CCP2 Synchronous
8-bit A/DTimer0 Timer1 Timer2
Serial Port
RA3/AN3/VREF
RA2/AN2
RA1/AN1
RA0/AN0
Parallel Slave Port
8
3
RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
Device Program FLASH Data Memory
PIC16F74 4K 192 Bytes
PIC16F77 8K 368 Bytes
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
CCP1
PIC16F7X
DS30325B-page 8 2002 Microchip Technology Inc.
TABLE 1-2: PIC16F73 AND PIC16F76 PINOUT DESCRIPTION
Pin Name
DIP
SSOP
SOIC
Pin#
MLF
Pin# I/O/P
Type Buffer
Type Description
OSC1/CLKI
OSC1
CLKI
96
I
I
ST/CMOS(3) Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input. ST
buffer when configured in RC mode. Otherwise CMOS.
External clock source input. Always associated with pin
function OSC1 (see OSC1/CLKI, OSC2/CLKO pins).
OSC2/CLKO
OSC2
CLKO
10 7
O
O
Oscillator crystal or clock output.
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
MCLR
VPP
126
I
P
ST Master Clear (input) or programming voltage (output).
Master Clear (Reset) input. This pin is an active low
RESET to the device.
Programming voltage input.
PORTA is a bi-directional I/O port.
RA0/AN0
RA0
AN0
227
I/O
I
TTL
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
328
I/O
I
TTL
Digital I/O.
Analog input 1.
RA2/AN2
RA2
AN2
41
I/O
I
TTL
Digital I/O.
Analog input 2.
RA3/AN3/VREF
RA3
AN3
VREF
52
I/O
I
I
TTL
Digital I/O.
Analog input 3.
A/D reference voltage input.
RA4/T0CKI
RA4
T0CKI
64
I/O
I
ST
Digital I/O Open drain when configured as output.
Timer0 external clock input.
RA5/SS/AN4
RA5
SS
AN4
75
I/O
I
I
TTL
Digital I/O.
SPI slave select input.
Analog input 4.
Legend: I = input O = output I/O = input/output P = power
= Not used TTL = TTL input ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
2002 Microchip Technology Inc. DS30325B-page 9
PIC16F7X
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-up on all inputs.
RB0/INT
RB0
INT
21 18 I/O
I
TTL/ST(1)
Digital I/O.
External interrupt.
RB1 22 19 I/O TTL Digital I/O.
RB2 23 20 I/O TTL Digital I/O.
RB3/PGM
RB3
PGM
24 21 I/O
I/O
TTL
Digital I/O.
Low voltage ICSP programming enable pin.
RB4 25 22 I/O TTL Digital I/O.
RB5 26 23 I/O TTL Digital I/O.
RB6/PGC
RB6
PGC
27 24 I/O
I/O
TTL/ST(2)
Digital I/O.
In-Circuit Debugger and ICSP programming clock.
RB7/PGD
RB7
PGD
28 25 I/O
I/O
TTL/ST(2)
Digital I/O.
In-Circuit Debugger and ICSP programming data.
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI
RC0
T1OSO
T1CKI
11 8
I/O
O
I
ST
Digital I/O.
Timer1 oscillator output.
Timer1 external clock input.
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2
12 9
I/O
I
I/O
ST
Digital I/O.
Timer1 oscillator input.
Capture2 input, Compare2 output, PWM2 output.
RC2/CCP1
RC2
CCP1
13 10
I/O
I/O
ST
Digital I/O.
Capture1 input/Compare1 output/PWM1 output.
RC3/SCK/SCL
RC3
SCK
SCL
14 11
I/O
I/O
I/O
ST
Digital I/O.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C mode.
RC4/SDI/SDA
RC4
SDI
SDA
15 12
I/O
I
I/O
ST
Digital I/O.
SPI data in.
I2C data I/O.
RC5/SDO
RC5
SDO
16 13
I/O
O
ST
Digital I/O.
SPI data out.
RC6/TX/CK
RC6
TX
CK
17 14
I/O
O
I/O
ST
Digital I/O.
USART asynchronous transmit.
USART 1 synchronous clock.
RC7/RX/DT
RC7
RX
DT
18 15
I/O
I
I/O
ST
Digital I/O.
USART asynchronous receive.
USART synchronous data.
VSS 8, 19 5, 16 P Ground reference for logic and I/O pins.
VDD 20 17 P Positive supply for logic and I/O pins.
TABLE 1-2: PIC16F73 AND PIC16F76 PINOUT DESCRIPTION (CONTINUED)
Pin Name
DIP
SSOP
SOIC
Pin#
MLF
Pin# I/O/P
Type Buffer
Type Description
Legend: I = input O = output I/O = input/output P = power
= Not used TTL = TTL input ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
PIC16F7X
DS30325B-page 10 2002 Microchip Technology Inc.
TABLE 1-3: PIC16F74 AND PIC16F77 PINOUT DESCRIPTION
Pin Name DIP
Pin# PLCC
Pin# QFP
Pin# I/O/P
Type Buffer
Type Description
OSC1/CLKI
OSC1
CLKI
13 14 30
I
I
ST/CMOS(4) Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode. Otherwise
CMOS.
External clock source input. Always associated with pin
function OSC1 (see OSC1/CLKI, OSC2/CLKO pins).
OSC2/CLKO
OSC2
CLKO
14 15 31
O
O
Oscillator crystal or clock output.
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
MCLR
VPP
1218
I
P
ST Master Clear (input) or programming voltage (output).
Master Clear (Reset) input. This pin is an active low
RESET to the device.
Programming voltage input.
PORTA is a bi-directional I/O port.
RA0/AN0
RA0
AN0
2319
I/O
I
TTL
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
3420
I/O
I
TTL
Digital I/O.
Analog input 1.
RA2/AN2
RA2
AN2
4521
I/O
I
TTL
Digital I/O.
Analog input 2.
RA3/AN3/VREF
RA3
AN3
VREF
5622
I/O
I
I
TTL
Digital I/O.
Analog input 3.
A/D reference voltage input.
RA4/T0CKI
RA4
T0CKI
6723
I/O
I
ST
Digital I/O Open drain when configured as output.
Timer0 external clock input.
RA5/SS/AN4
RA5
SS
AN4
7824
I/O
I
I
TTL
Digital I/O.
SPI slave select input.
Analog input 4.
Legend: I = input O = output I/O = input/output P = power
= Not used TTL = TTL input ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as an external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3: This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
4: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
2002 Microchip Technology Inc. DS30325B-page 11
PIC16F7X
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-up on all inputs.
RB0/INT
RB0
INT
33 36 8 I/O
I
TTL/ST(1)
Digital I/O.
External interrupt.
RB1 34 37 9 I/O TTL Digital I/O.
RB2 353810I/O TTL Digital I/O.
RB3/PGM
RB3
PGM
36 39 11 I/O
I/O
TTL
Digital I/O.
Low voltage ICSP programming enable pin.
RB4 374114I/O TTL Digital I/O.
RB5 384215I/O TTL Digital I/O.
RB6/PGC
RB6
PGC
39 43 16 I/O
I/O
TTL/ST(2)
Digital I/O.
In-Circuit Debugger and ICSP programming clock.
RB7/PGD
RB7
PGD
40 44 17 I/O
I/O
TTL/ST(2)
Digital I/O.
In-Circuit Debugger and ICSP programming data.
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI
RC0
T1OSO
T1CKI
15 16 32
I/O
O
I
ST
Digital I/O.
Timer1 oscillator output.
Timer1 external clock input.
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2
16 18 35
I/O
I
I/O
ST
Digital I/O.
Timer1 oscillator input.
Capture2 input, Compare2 output, PWM2 output.
RC2/CCP1
RC2
CCP1
17 19 36
I/O
I/O
ST
Digital I/O.
Capture1 input/Compare1 output/PWM1 output
RC3/SCK/SCL
RC3
SCK
SCL
18 20 37
I/O
I/O
I/O
ST
Digital I/O
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C mode.
RC4/SDI/SDA
RC4
SDI
SDA
23 25 42
I/O
I
I/O
ST
Digital I/O.
SPI data in.
I2C data I/O.
RC5/SDO
RC5
SDO
24 26 43
I/O
O
ST
Digital I/O.
SPI data out.
RC6/TX/CK
RC6
TX
CK
25 27 44
I/O
O
I/O
ST
Digital I/O.
USART asynchronous transmit.
USART 1 synchronous clock.
RC7/RX/DT
RC7
RX
DT
26 29 1
I/O
I
I/O
ST
Digital I/O.
USART asynchronous receive.
USART synchronous data.
TABLE 1-3: PIC16F74 AND PIC16F77 PINOUT DESCRIPTION (CONTINUED)
Pin Name DIP
Pin# PLCC
Pin# QFP
Pin# I/O/P
Type Buffer
Type Description
Legend: I = input O = output I/O = input/output P = power
= Not used TTL = TTL input ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as an external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3: This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
4: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
PIC16F7X
DS30325B-page 12 2002 Microchip Technology Inc.
PORTD is a bi-directional I/O port or parallel slave port
when interfacing to a microprocessor bus.
RD0/PSP0
RD0
PSP0
19 21 38
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD1/PSP1
RD1
PSP1
20 22 39 I
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD2/PSP2
RD2
PSP2
21 23 40 I
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD3/PSP3
RD3
PSP3
22 24 41
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD4/PSP4
RD4
PSP4
27 30 2
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD5/PSP5
RD5
PSP5
28 31 3
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD6/PSP6
RD6
PSP6
29 32 4
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
RD7/PSP7
RD7
PSP7
30 33 5
I/O
I/O
ST/TTL(3)
Digital I/O.
Parallel Slave Port data.
PORTE is a bi-directional I/O port.
RE0/RD/AN5
RE0
RD
AN5
8925
I/O
I
I
ST/TTL(3)
Digital I/O.
Read control for parallel slave port .
Analog input 5.
RE1/WR/AN6
RE1
WR
AN6
91026
I/O
I
I
ST/TTL(3)
Digital I/O.
Write control for parallel slave port .
Analog input 6.
RE2/CS/AN7
RE2
CS
AN7
10 11 27
I/O
I
I
ST/TTL(3)
Digital I/O.
Chip select control for parallel slave port .
Analog input 7.
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 1,17,2
8, 40
12,13,
33, 34
These pins are not internally connected. These pins should
be left unconnected.
TABLE 1-3: PIC16F74 AND PIC16F77 PINOUT DESCRIPTION (CONTINUED)
Pin Name DIP
Pin# PLCC
Pin# QFP
Pin# I/O/P
Type Buffer
Type Description
Legend: I = input O = output I/O = input/output P = power
= Not used TTL = TTL input ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as an external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3: This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
4: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
2002 Microchip Technology Inc. DS30325B-page 13
PIC16F7X
2.0 MEMORY ORGANIZATION
There are two memory blocks in each of these
PICmicro® MCUs. The Program Memory and Data
Memory have separate buses so that concurrent
access can occur and is detailed in this section. The
Program Memory can be read internally by user code
(see Section 3.0).
Additional information on device memory may be found
in the PICmicro Mid-Range Reference Manual
(DS33023).
2.1 Program Memory Organization
The PIC16F7X devices have a 13-bit program counter
capable of addressing an 8K word x 14-bit program
memory space. The PIC16F77/76 devices have
8K words of FLASH program memory and the
PIC16F73/74 devices have 4K words. The program
memory maps for PIC16F7X devices are shown in
Figure 2-1. 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.
2.2 Data Memory Organization
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:
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 Regis-
ters are General Purpose Registers, implemented as
static RAM. All implemented banks contain Special
Function Registers. Some frequently used Special
Function Registers from one bank may be mirrored in
another bank for code reduction and quicker access.
2.2.1 GENERAL PURPOSE REGISTER
FILE
The register file (shown in Figure 2-2 and Figure 2-3)
can be accessed either directly, or indirectly, through
the File Select Register FSR.
FIGURE 2-1: PROGRAM MEMORY MAPS AND STACKS FOR PIC16F7X DEVICES
RP1:RP0 Bank
00 0
01 1
10 2
11 3
PC<12:0>
13
0000h
0004h
0005h
Stack Level 1
Stack Level 8
RESET Vector
Interrupt Vector
On-Chip
CALL, RETURN
RETFIE, RETLW
1FFFh
Stack Level 2
Program
Memory
Page 0
Page 1
07FFh
0800h
0FFFh
1000h
17FFh
1800h
RESET Vector
Interrupt Vector
Page 0
Page 1
Page 2
Page 3
0000h
0004h
0005h
1FFFh
07FFh
0800h
0FFFh
1000h
PC<12:0>
13
Stack Level 1
Stack Level 8
CALL, RETURN
RETFIE, RETLW
Stack Level 2
Unimplemented
Read as 0
On-Chip
Program
Memory
PIC16F76/77 PIC16F73/74
FCL STATUS FSR TRISA TRISE TR‘SC PCLATH INTCON FOL STATU S FSR PCLATH INTCON
PIC16F7X
DS30325B-page 14 2002 Microchip Technology Inc.
FIGURE 2-2: PIC16F77/76 REGISTER FILE MAP
Indirect addr.(*)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
PCLATH
INTCON
PIR1
TMR1L
TMR1H
T1CON
TMR2
T2CON
SSPBUF
SSPCON
CCPR1L
CCPR1H
CCP1CON
OPTION_REG
PCL
STATUS
FSR
TRISA
TRISB
TRISC
PCLATH
INTCON
PIE1
PCON
PR2
SSPSTAT
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
20h A0h
7Fh FFh
Bank 0 Bank 1
Unimplemented data memory locations, read as 0.
* Not a physical register.
Note 1: These registers are not implemented on 28-pin devices.
File
Address
Indirect addr.(*) Indirect addr.(*)
PCL
STATUS
FSR
PCLATH
INTCON
PCL
STATUS
FSR
PCLATH
INTCON
100h
101h
102h
103h
104h
105h
106h
107h
108h
109h
10Ah
10Bh
10Ch
10Dh
10Eh
10Fh
110h
111h
112h
113h
114h
115h
116h
117h
118h
119h
11Ah
11Bh
11Ch
11Dh
11Eh
11Fh
180h
181h
182h
183h
184h
185h
186h
187h
188h
189h
18Ah
18Bh
18Ch
18Dh
18Eh
18Fh
190h
191h
192h
193h
194h
195h
196h
197h
198h
199h
19Ah
19Bh
19Ch
19Dh
19Eh
19Fh
120h 1A0h
17Fh 1FFh
Bank 2 Bank 3
Indirect addr.(*)
PORTD(1)
PORTE(1) TRISD(1)
TRISE(1)
TMR0 OPTION_REG
PIR2 PIE2
RCSTA
TXREG
RCREG
CCPR2L
CCPR2H
CCP2CON
ADRES
ADCON0
TXSTA
SPBRG
ADCON1
General
Purpose
Register
General
Purpose
Register
General
Purpose
Register
General
Purpose
Register
1EFh
1F0h
accesses
70h - 7Fh
EFh
F0h
accesses
70h-7Fh
16Fh
170h
accesses
70h-7Fh
General
Purpose
Register
General
Purpose
Register
TRISB
PORTB
96 Bytes 80 Bytes 80 Bytes 80 Bytes
16 Bytes 16 Bytes
PMDATA
PMADR
PMCON1
PMDATH
PMADRH
File
Address
File
Address
File
Address
SSPADD
OPTION REG FCL STATUS FSR TRISA TRISE TRTSC PCLATH INTCON POL STATUS FSR PORTB PCLATH INTCON
2002 Microchip Technology Inc. DS30325B-page 15
PIC16F7X
FIGURE 2-3: PIC16F74/73 REGISTER FILE MAP
Indirect addr.(*)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
PCLATH
INTCON
PIR1
TMR1L
TMR1H
T1CON
TMR2
T2CON
SSPBUF
SSPCON
CCPR1L
CCPR1H
CCP1CON
OPTION_REG
PCL
STATUS
FSR
TRISA
TRISB
TRISC
PCLATH
INTCON
PIE1
PCON
PR2
SSPSTAT
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
20h A0h
7Fh FFh
Bank 0 Bank 1
File
Address
Indirect addr.(*) Indirect addr.(*)
PCL
STATUS
FSR
PCLATH
INTCON
PCL
STATUS
FSR
PCLATH
INTCON
100h
101h
102h
103h
104h
105h
106h
107h
108h
109h
10Ah
10Bh
180h
181h
182h
183h
184h
185h
186h
187h
188h
189h
18Ah
18Bh
17Fh 1FFh
Bank 2 Bank 3
Indirect addr.(*)
PORTD(1)
PORTE(1) TRISD(1)
TRISE(1)
TMR0 OPTION_REG
PIR2 PIE2
RCSTA
TXREG
RCREG
CCPR2L
CCPR2H
CCP2CON
ADRES
ADCON0
TXSTA
SPBRG
ADCON1
General
Purpose
Register
General
Purpose
Register
1EFh
1F0h
accesses
A0h - FFh
16Fh
170h
accesses
20h-7Fh
TRISB
PORTB
96 Bytes 96 Bytes
10Ch
10Dh
10Eh
10Fh
110h
18Ch
18Dh
18Eh
18Fh
190h
PMDATA
PMADR
PMCON1
PMDATH
PMADRH
Unimplemented data memory locations, read as 0.
* Not a physical register.
Note 1: These registers are not implemented on 28-pin devices.
120h 1A0h
File
Address
File
Address
File
Address
SSPADD
PIC16F7X
DS30325B-page 16 2002 Microchip Technology Inc.
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.
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.
TABLE 2-1: SPECIAL FUNCTION REGISTER SUMMARY
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Details
on page
Bank 0
00h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 27, 96
01h TMR0 Timer0 Module Register xxxx xxxx 45, 96
02h(4) PCL Program Counter (PC) Least Significant Byte 0000 0000 26, 96
03h(4) STATUS IRP RP1 RP0 TO PD ZDCC
0001 1xxx 19, 96
04h(4) FSR Indirect Data Memory Address Pointer xxxx xxxx 27, 96
05h PORTA PORTA Data Latch when written: PORTA pins when read --0x 0000 32, 96
06h PORTB PORTB Data Latch when written: PORTB pins when read xxxx xxxx 34, 96
07h PORTC PORTC Data Latch when written: PORTC pins when read xxxx xxxx 35, 96
08h(5) PORTD PORTD Data Latch when written: PORTD pins when read xxxx xxxx 36, 96
09h(5) PORTE RE2 RE1 RE0 ---- -xxx 39, 96
0Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 26, 96
0Bh(4) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 21, 96
0Ch PIR1 PSPIF(3) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 23, 96
0Dh PIR2 CCP2IF ---- ---0 24, 96
0Eh TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx 50, 96
0Fh TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx 50, 96
10h T1CON T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 47, 96
11h TMR2 Timer2 Module Register 0000 0000 52, 96
12h T2CON TOUTPS3 TOUTPS2 TOUTPS TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 52, 96
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx 64, 68, 96
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 61, 96
15h CCPR1L Capture/Compare/PWM Register1 (LSB) xxxx xxxx 56, 96
16h CCPR1H Capture/Compare/PWM Register1 (MSB) xxxx xxxx 56, 96
17h CCP1CON CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 54, 96
18h RCSTA SPEN RX9 SREN CREN FERR OERR RX9D 0000 -00x 70, 96
19h TXREG USART Transmit Data Register 0000 0000 74, 96
1Ah RCREG USART Receive Data Register 0000 0000 76, 96
1Bh CCPR2L Capture/Compare/PWM Register2 (LSB) xxxx xxxx 58, 96
1Ch CCPR2H Capture/Compare/PWM Register2 (MSB) xxxx xxxx 58, 96
1Dh CCP2CON CCP2X CCP2Y CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 54, 96
1Eh ADRES A/D Result Register Byte xxxx xxxx 88, 96
1Fh ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/
DONE ADON 0000 00-0 83, 96
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as '0', r = reserved.
Shaded locations are unimplemented, read as 0.
Note 1: 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 during branches (CALL or GOTO).
2: Other (non power-up) RESETS include external RESET through MCLR and Watchdog Timer Reset.
3: Bits PSPIE and PSPIF are reserved on the 28-pin devices; always maintain these bits clear.
4: These registers can be addressed from any bank.
5: PORTD, PORTE, TRISD, and TRISE are not physically implemented on the 28-pin devices, read as 0.
6: This bit always reads as a 1.
2002 Microchip Technology Inc. DS30325B-page 17
PIC16F7X
Bank 1
80h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 27, 96
81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 20, 44, 96
82h(4) PCL Program Counters (PC) Least Significant Byte 0000 0000 26, 96
83h(4) STATUS IRP RP1 RP0 TO PD ZDCC0001 1xxx 19, 96
84h(4) FSR Indirect data memory address pointer xxxx xxxx 27, 96
85h TRISA PORTA Data Direction Register --11 1111 32, 96
86h TRISB PORTB Data Direction Register 1111 1111 34, 96
87h TRISC PORTC Data Direction Register 1111 1111 35, 96
88h(5) TRISD PORTD Data Direction Register 1111 1111 36, 96
89h(5) TRISE IBF OBF IBOV PSPMODE PORTE Data Direction Bits 0000 -111 38, 96
8Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 21, 96
8Bh(4) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 23, 96
8Ch PIE1 PSPIE(3) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 22, 96
8Dh PIE2 CCP2IE ---- ---0 24, 97
8Eh PCON POR BOR ---- --qq 25, 97
8Fh Unimplemented
90h Unimplemented
91h Unimplemented
92h PR2 Timer2 Period Register 1111 1111 52, 97
93h SSPADD Synchronous Serial Port (I2C mode) Address Register 0000 0000 68, 97
94h SSPSTAT SMP CKE D/A PSR/WUA BF 0000 0000 60, 97
95h Unimplemented
96h Unimplemented
97h Unimplemented
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 69, 97
99h SPBRG Baud Rate Generator Register 0000 0000 71, 97
9Ah Unimplemented
9Bh Unimplemented
9Ch Unimplemented
9Dh Unimplemented
9Eh Unimplemented
9Fh ADCON1 PCFG2 PCFG1 PCFG0 ---- -000 84, 97
TABLE 2-1: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Details
on page
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as '0', r = reserved.
Shaded locations are unimplemented, read as 0.
Note 1: 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 during branches (CALL or GOTO).
2: Other (non power-up) RESETS include external RESET through MCLR and Watchdog Timer Reset.
3: Bits PSPIE and PSPIF are reserved on the 28-pin devices; always maintain these bits clear.
4: These registers can be addressed from any bank.
5: PORTD, PORTE, TRISD, and TRISE are not physically implemented on the 28-pin devices, read as 0.
6: This bit always reads as a 1.
PIC16F7X
DS30325B-page 18 2002 Microchip Technology Inc.
Bank 2
100h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 27, 96
101h TMR0 Timer0 Module Register xxxx xxxx 45, 96
102h(4) PCL Program Counter (PC) Least Significant Byte 0000 0000 26, 96
103h(4) STATUS IRP RP1 RP0 TO PD ZDCC0001 1xxx 19, 96
104h(4) FSR Indirect Data Memory Address Pointer xxxx xxxx 27, 96
105h Unimplemented
106h PORTB PORTB Data Latch when written: PORTB pins when read xxxx xxxx 34, 96
107h Unimplemented
108h Unimplemented
109h Unimplemented
10Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 21, 96
10Bh(4) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 23, 96
10Ch PMDATA Data Register Low Byte xxxx xxxx 29, 97
10Dh PMADR Address Register Low Byte xxxx xxxx 29, 97
10Eh PMDATH Data Register High Byte xxxx xxxx 29, 97
10Fh PMADRH Address Register High Byte xxxx xxxx 29, 97
Bank 3
180h(4) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 27, 96
181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 20, 44, 96
182h(4) PCL Program Counter (PC) Least Significant Byte 0000 0000 26, 96
183h(4) STATUS IRP RP1 RP0 TO PD ZDCC
0001 1xxx 19, 96
184h(4) FSR Indirect Data Memory Address Pointer xxxx xxxx 27, 96
185h Unimplemented
186h TRISB PORTB Data Direction Register 1111 1111 34, 96
187h Unimplemented
188h Unimplemented
189h Unimplemented
18Ah(1,4) PCLATH Write Buffer for the upper 5 bits of the Program Counter ---0 0000 21, 96
18Bh(4) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 23, 96
18Ch PMCON1 (6) RD 1--- ---0 29, 97
18Dh Unimplemented
18Eh Reserved maintain clear 0000 0000
18Fh Reserved maintain clear 0000 0000
TABLE 2-1: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Details
on page
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as '0', r = reserved.
Shaded locations are unimplemented, read as 0.
Note 1: 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 during branches (CALL or GOTO).
2: Other (non power-up) RESETS include external RESET through MCLR and Watchdog Timer Reset.
3: Bits PSPIE and PSPIF are reserved on the 28-pin devices; always maintain these bits clear.
4: These registers can be addressed from any bank.
5: PORTD, PORTE, TRISD, and TRISE are not physically implemented on the 28-pin devices, read as 0.
6: This bit always reads as a 1.
2002 Microchip Technology Inc. DS30325B-page 19
PIC16F7X
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.
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."
REGISTER 2-1: STATUS REGISTER (ADDRESS 03h, 83h, 103h, 183h)
Note 1: The C and DC bits operate as a borrow
and digit borrow bit, respectively, in sub-
traction. See the SUBLW and SUBWF
instructions for examples.
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 ZDC C
bit 7 bit 0
bit 7 IRP: Register Bank Select bit (used for indirect addressing)
1 = Bank 2, 3 (100h - 1FFh)
0 = Bank 0, 1 (00h - FFh)
bit 6-5 RP1:RP0: Register Bank Select bits (used for direct addressing)
11 = Bank 3 (180h - 1FFh)
10 = Bank 2 (100h - 17Fh)
01 = Bank 1 (80h - FFh)
00 = Bank 0 (00h - 7Fh)
Each bank is 128 bytes
bit 4 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)
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 twos
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:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
PIC16F7X
DS30325B-page 20 2002 Microchip Technology Inc.
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 assign-
able register known also as the prescaler), the External
INT Interrupt, TMR0 and the weak pull-ups on PORTB.
REGISTER 2-2: OPTION_REG REGISTER (ADDRESS 81h, 181h)
Note: To achieve a 1:1 prescaler assignment for
the TMR0 register, assign the prescaler to
the Watchdog Timer.
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 (CLKOUT)
bit 4 T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on RA4/T0CKI pin
0 = Increment on low-to-high transition on RA4/T0CKI pin
bit 3 PSA: Prescaler Assignment bit
1 = Prescaler is assigned to the WDT
0 = Prescaler is assigned to the Timer0 module
bit 2-0 PS2:PS0: Prescaler Rate Select bits
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
000
001
010
011
100
101
110
111
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
Bit Value TMR0 Rate WDT Rate
2002 Microchip Technology Inc. DS30325B-page 21
PIC16F7X
2.2.2.3 INTCON Register
The INTCON register is a readable and writable regis-
ter, which contains various enable and flag bits for the
TMR0 register overflow, RB Port change and External
RB0/INT pin interrupts.
REGISTER 2-3: INTCON REGISTER (ADDRESS 0Bh, 8Bh, 10Bh, 18Bh)
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>). User soft-
ware should ensure the appropriate inter-
rupt flag bits are clear prior to enabling an
interrupt.
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 TMR0IE INTE RBIE TMR0IF 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 TMR0IE: 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 TMR0IF: 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
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.
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:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
PIC16F7X
DS30325B-page 22 2002 Microchip Technology Inc.
2.2.2.4 PIE1 Register
The PIE1 register contains the individual enable bits for
the peripheral interrupts.
REGISTER 2-4: PIE1 REGISTER (ADDRESS 8Ch)
Note: Bit PEIE (INTCON<6>) must be set to
enable any peripheral interrupt.
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PSPIE(1) ADIE RCIE TXIE SSPIE 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 SSPIE: Synchronous Serial Port Interrupt Enable bit
1 = Enables the SSP interrupt
0 = Disables the SSP interrupt
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 28-pin devices; always maintain this bit clear.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
fl I20 Slave I20 Master Cagmre mode Comgare mode: PWM mode
2002 Microchip Technology Inc. DS30325B-page 23
PIC16F7X
2.2.2.5 PIR1 Register
The PIR1 register contains the individual flag bits for
the peripheral interrupts.
REGISTER 2-5: PIR1 REGISTER (ADDRESS 0Ch)
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>). User soft-
ware should ensure the appropriate interrupt
bits are clear prior to enabling an interrupt.
R/W-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0
PSPIF(1) ADIF RCIF TXIF SSPIF 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 is completed (must be cleared in software)
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 SSPIF: Synchronous Serial Port (SSP) Interrupt Flag
1 = The SSP interrupt condition has occurred, and must be cleared in software before
returning from the Interrupt Service Routine. The conditions that will set this bit are:
SPI
A transmission/reception has taken place.
I2 C Slave
A transmission/reception has taken place.
I2 C Master
A transmission/reception has taken place.
The initiated START condition was completed by the SSP module.
The initiated STOP condition was completed by the SSP module.
The initiated Restart condition was completed by the SSP module.
The initiated Acknowledge condition was completed by the SSP module.
A START condition occurred while the SSP module was IDLE (multi-master system).
A STOP condition occurred while the SSP module was IDLE (multi-master system).
0 = No SSP interrupt condition has occurred
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 28-pin devices; always maintain this bit clear.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
Caglure mode. Comgare mode. PWM mode.
PIC16F7X
DS30325B-page 24 2002 Microchip Technology Inc.
2.2.2.6 PIE2 Register
The PIE2 register contains the individual enable bits for
the CCP2 peripheral interrupt.
REGISTER 2-6: PIE2 REGISTER (ADDRESS 8Dh)
2.2.2.7 PIR2 Register
The PIR2 register contains the flag bits for the CCP2
interrupt.
REGISTER 2-7: PIR2 REGISTER (ADDRESS 0Dh)
U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0
— — — — CCP2IE
bit 7 bit 0
bit 7-1 Unimplemented: Read as '0'
bit 0 CCP2IE: CCP2 Interrupt Enable bit
1 = Enables the CCP2 interrupt
0 = Disables the CCP2 interrupt
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>). User soft-
ware should ensure the appropriate inter-
rupt flag bits are clear prior to enabling an
interrupt.
U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0
CCP2IF
bit 7 bit 0
bit 7-1 Unimplemented: Read as '0'
bit 0 CCP2IF: CCP2 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
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
2002 Microchip Technology Inc. DS30325B-page 25
PIC16F7X
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.
REGISTER 2-8: PCON REGISTER (ADDRESS 8Eh)
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 not predictable if the brown-out circuit
is disabled (by clearing the BODEN bit in
the configuration word).
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 reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
Instrudmn wnh , Desunauon
PIC16F7X
DS30325B-page 26 2002 Microchip Technology Inc.
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 2-4 shows the two situations
for the loading of the PC. The upper example in the fig-
ure shows how the PC is loaded on a write to PCL
(PCLATH<4:0> PCH). The lower example in the fig-
ure shows how the PC is loaded during a CALL or GOTO
instruction (PCLATH<4:3> PCH).
FIGURE 2-4: LOADING OF PC IN
DIFFERENT SITUATIONS
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 PIC16F7X 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.
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).
2.4 Program Memory Paging
PIC16F7X devices are capable of addressing a contin-
uous 8K word block of program memory. The CALL and
GOTO instructions provide only 11 bits of address to
allow branching within any 2K program memory page.
When doing a CALL or GOTO instruction, the upper 2
bits of the address are provided by PCLATH<4:3>.
When doing a CALL or GOTO instruction, the user must
ensure that the page select bits are programmed so
that the desired program memory page is addressed. If
a return from a CALL instruction (or interrupt) is exe-
cuted, the entire 13-bit PC is popped off the stack.
Therefore, manipulation of the PCLATH<4:3> bits are
not required for the RETURN instructions (which POPs
the address from the stack).
Example 2-1 shows the calling of a subroutine in
page 1 of the program memory. This example assumes
that PCLATH is saved and restored by the Interrupt
Service Routine (if interrupts are used).
EXAMPLE 2-1: CALL OF A SUBROUTINE
IN PAGE 1 FROM PAGE 0
PC
12 8 7 0
5PCLATH<4:0>
PCLATH
Instruction with
ALU
GOTO,CALL
Opcode <10:0>
8
PC
12 11 10 0
11
PCLATH<4:3>
PCH PCL
87
2
PCLATH
PCH PCL
PCL as
Destination
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 inter-
rupt address.
Note: The contents of the PCLATH are
unchanged after a RETURN or RETFIE
instruction is executed. The user must
setup the PCLATH for any subsequent
CALLS or GOTOS.
ORG 0x500
BCF PCLATH,4
BSF PCLATH,3 ;Select page 1
;(800h-FFFh)
CALL SUB1_P1 ;Call subroutine in
: ;page 1 (800h-FFFh)
:
ORG 0x900 ;page 1 (800h-FFFh)
SUB1_P1
: ;called subroutine
: ;page 1 (800h-FFFh)
:
RETURN ;return to Call
;subroutine in page 0
;(000h-7FFh)
Um
2002 Microchip Technology Inc. DS30325B-page 27
PIC16F7X
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 reg-
ister. Any instruction using the INDF register actually
accesses the register pointed to by the File Select Reg-
ister, 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 2-5.
A simple program to clear RAM locations 20h-2Fh
using indirect addressing is shown in Example 2-2.
EXAMPLE 2-2: INDIRECT ADDRESSING
FIGURE 2-5: DIRECT/INDIRECT ADDRESSING
MOVLW 0x20 ;initialize pointer
MOVWF FSR ;to RAM
NEXT CLRF INDF ;clear INDF register
INCF FSR,F ;inc pointer
BTFSS FSR,4 ;all done?
GOTO NEXT ;no clear next
CONTINUE
: ;yes continue
Note 1: For register file map detail, see Figure 2-2.
Data
Memory(1)
Indirect AddressingDirect Addressing
Bank Select Location Select
RP1:RP0 6 0
From Opcode IRP FSR Register
70
Bank Select Location Select
00 01 10 11
Bank 0 Bank 1 Bank 2 Bank 3
FFh
80h
7Fh
00h
17Fh
100h
1FFh
180h
PIC16F7X
DS30325B-page 28 2002 Microchip Technology Inc.
NOTES:
2002 Microchip Technology Inc. DS30325B-page 29
PIC16F7X
3.0 READING PROGRAM MEMORY
The FLASH Program Memory is readable during nor-
mal operation over the entire VDD range. It is indirectly
addressed through Special Function Registers (SFR).
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 con-
taining data that forms an invalid instruction results in a
NOP.
There are five SFRs used to read the program and
memory. These registers are:
PMCON1
PMDATA
PMDATH
PMADR
PMADRH
The program memory allows word reads. Program
memory access allows for checksum calculation and
reading calibration tables.
When interfacing to the program memory block, the
PMDATH:PMDATA registers form a two-byte word,
which holds the 14-bit data for reads. The
PMADRH:PMADR registers form a two-byte word,
which holds the 13-bit address of the FLASH location
being accessed. These devices can have up to 8K
words of program FLASH, with an address range from
0h to 3FFFh. The unused upper bits in both the
PMDATH and PMADRH registers are not implemented
and read as 0s.
3.1 PMADR
The address registers can address up to a maximum of
8K words of program FLASH.
When selecting a program address value, the MSByte
of the address is written to the PMADRH register and
the LSByte is written to the PMADR register. The upper
MSbits of PMADRH must always be clear.
3.2 PMCON1 Register
PMCON1 is the control register for memory accesses.
The control bit RD initiates read operations. This bit
cannot be cleared, only set, in software. It is cleared in
hardware at the completion of the read operation.
REGISTER 3-1: PMCON1 REGISTER (ADDRESS 18Ch)
R-1 U-0 U-0 U-0 U-x U-0 U-0 R/S-0
reserved — — — — — — RD
bit 7 bit 0
bit 7 Reserved: Read as 1
bit 6-1 Unimplemented: Read as '0'
bit 0 RD: Read Control bit
1 = Initiates a FLASH read, RD is cleared in hardware. The RD bit can only be set (not cleared)
in software.
0 = FLASH read completed
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
PIC16F7X
DS30325B-page 30 2002 Microchip Technology Inc.
3.3 Reading the FLASH Program
Memory
A program memory location may be read by writing two
bytes of the address to the PMADR and PMADRH reg-
isters and then setting control bit RD (PMCON1<0>).
Once the read control bit is set, the microcontroller will
use the next two instruction cycles to read the data. The
data is available in the PMDATA and PMDATH regis-
ters after the second NOP instruction. Therefore, it can
be read as two bytes in the following instructions. The
PMDATA and PMDATH registers will hold this value
until the next read operation.
3.4 Operation During Code Protect
FLASH program memory has its own code protect
mechanism. External Read and Write operations by
programmers are disabled if this mechanism is
enabled.
The microcontroller can read and execute instructions
out of the internal FLASH program memory, regardless
of the state of the code protect configuration bits.
EXAMPLE 3-1: FLASH PROGRAM READ
TABLE 3-1: REGISTERS ASSOCIATED WITH PROGRAM FLASH
BSF STATUS, RP1 ;
BCF STATUS, RP0 ; Bank 2
MOVF ADDRH, W ;
MOVWF PMADRH ; MSByte of Program Address to read
MOVF ADDRL, W ;
MOVWF PMADR ; LSByte of Program Address to read
BSF STATUS, RP0 ; Bank 3 Required
Required BSF PMCON1, RD ; EEPROM Read Sequence
Sequence NOP ; memory is read in the next two cycles after BSF PMCON1,RD
NOP ;
BCF STATUS, RP0 ; Bank 2
MOVF PMDATA, W ; W = LSByte of Program PMDATA
MOVF PMDATH, W ; W = MSByte of Program PMDATA
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
10Dh PMADR Address Register Low Byte xxxx xxxx uuuu uuuu
10Fh PMADRH Address Register High Byte xxxx xxxx uuuu uuuu
10Ch PMDATA Data Register Low Byte xxxx xxxx uuuu uuuu
10Eh PMDATH Data Register High Byte xxxx xxxx uuuu uuuu
18Ch PMCON1 (1) — — — — — — RD 1--- ---0 1--- ---0
Legend: x = unknown, u = unchanged, r = reserved, - = unimplemented read as '0'. Shaded cells are not used during FLASH access.
Note 1: This bit always reads as a 1.
Da|aBus WRPORT E I
2002 Microchip Technology Inc. DS30325B-page 31
PIC16F7X
4.0 I/O PORTS
Some pins for these I/O ports are multiplexed with an
alternate function for the peripheral features on the
device. In general, when a peripheral is enabled, that
pin may not be used as a general purpose I/O pin.
Additional information on I/O ports may be found in the
PICmicro Mid-Range Reference Manual,
(DS33023).
4.1 PORTA and the TRISA Register
PORTA is a 6-bit wide, bi-directional port. The corre-
sponding 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).
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.
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 Register1).
The TRISA register controls the direction of the RA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set, when using them as analog inputs.
EXAMPLE 4-1: INITIALIZING PORTA
FIGURE 4-1: BLOCK DIAGRAM OF
RA3:RA0 AND RA5 PINS
FIGURE 4-2: BLOCK DIAGRAM OF
RA4/T0CKI PIN
Note: On a Power-on Reset, these pins are con-
figured as analog inputs and read as '0'.
BCF STATUS, RP0 ;
BCF STATUS, RP1 ; Bank0
CLRF PORTA ; Initialize PORTA by
; clearing output
; data latches
BSF STATUS, RP0 ; Select Bank 1
MOVLW 0x06 ; Configure all pins
MOVWF ADCON1 ; as digital inputs
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISA ; Set RA<3:0> as inputs
; RA<5:4> as outputs
; TRISA<7:6>are always
; read as ’0’.
Data Bus
P
N
WR Port
WR TRIS
RD TRIS
RD PORT
VSS
VDD
I/O pin(1)
Note 1: I/O pins have protection diodes to VDD and VSS.
Analog
Input
Mode
TTL
Input
Buffer
To A/D Converter
EN
QD
EN
Data Latch
TRIS Latch
QD
Q
CK
QD
Q
CK
Data Bus
WR PORT
WRTRIS
RD PORT
Data Latch
TRIS Latch
RD TRIS
Schmitt
Trigger
Input
Buffer
N
VSS
I/O pin(1)
TMR0 Clock Input
QD
Q
CK
QD
Q
CK
EN
QD
EN
Note 1: I/O pin has protection diodes to VSS only.
PIC16F7X
DS30325B-page 32 2002 Microchip Technology Inc.
TABLE 4-1: PORTA FUNCTIONS
TABLE 4-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name Bit# Buffer Function
RA0/AN0 bit0 TTL Input/output or analog input.
RA1/AN1 bit1 TTL Input/output or analog input.
RA2/AN2 bit2 TTL Input/output or analog input.
RA3/AN3/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/SS/AN4 bit5 TTL Input/output or slave select input for synchronous serial port or analog input.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on all
other
RESETS
05h PORTA RA5 RA4 RA3 RA2 RA1 RA0 --0x 0000 --0u 0000
85h TRISA PORTA Data Direction Register --11 1111 --11 1111
9Fh ADCON1 PCFG2 PCFG1 PCFG0 ---- -000 ---- -000
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by PORTA.
Note: When using the SSP module in SPI Slave mode and SS enabled, the A/D converter must be set to one of
the following modes where PCFG2:PCFG0 = 100, 101, 11x.
mg RD Pun
2002 Microchip Technology Inc. DS30325B-page 33
PIC16F7X
4.2 PORTB and the TRISB Register
PORTB is an 8-bit wide, bi-directional port. The corre-
sponding 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).
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is per-
formed 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 dis-
abled on a Power-on Reset.
FIGURE 4-3: BLOCK DIAGRAM OF
RB3:RB0 PINS
Four of the PORTB pins (RB7:RB4) have an inter-
rupt-on-change feature. Only pins configured as inputs
can cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the inter-
rupt-on-change comparison). The input pins (of
RB7:RB4) are compared with the old value latched on
the last read of PORTB. The mismatch outputs of
RB7:RB4 are ORed together to generate the RB Port
Change Interrupt with flag bit RBIF (INTCON<0>).
This interrupt can wake the device from SLEEP. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a) Any read or write of PORTB. This will end the
mismatch condition.
b) Clear flag bit RBIF.
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
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 soft-
ware configureable 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 an external interrupt input pin and is config-
ured using the INTEDG bit (OPTION_REG<6>).
RB0/INT is discussed in detail in Section 12.11.1.
FIGURE 4-4: BLOCK DIAGRAM OF
RB7:RB4 PINS
Data Latch
RBPU(2)
P
VDD
QD
CK
QD
CK
QD
EN
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
Weak
Pull-up
RD Port
RB0/INT
I/O
pin(1)
TTL
Input
Buffer
Schmitt Trigger
Buffer
TRIS Latch
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
Data Latch
From other
RBPU(2)
P
VDD
I/O
QD
CK
QD
CK
QD
EN
QD
EN
Data Bus
WR Port
WR TRIS
Set RBIF
TRIS Latch
RD TRIS
RD Port
RB7:RB4 pins
Weak
Pull-up
RD Port
Latch
TTL
Input
Buffer
pin(1)
ST
Buffer
RB7:RB6 in Serial Programming mode
Q3
Q1
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (OPTION_REG<7>).
PIC16F7X
DS30325B-page 34 2002 Microchip Technology Inc.
TABLE 4-3: PORTB FUNCTIONS
TABLE 4-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Name Bit# Buffer Function
RB0/INT bit0 TTL/ST(1) Input/output pin or external interrupt input. Internal software
programmable weak pull-up.
RB1 bit1 TTL Input/output pin. Internal software programmable weak pull-up.
RB2 bit2 TTL Input/output pin. Internal software programmable weak pull-up.
RB3 bit3 TTL Input/output pin. Internal software programmable weak pull-up.
RB4 bit4 TTL Input/output pin (with interrupt-on-change). Internal software programmable
weak pull-up.
RB5 bit5 TTL Input/output pin (with interrupt-on-change). Internal software programmable
weak pull-up.
RB6 bit6 TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up. Serial programming clock.
RB7 bit7 TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up. Serial programming data.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
06h, 106h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu
86h, 186h TRISB PORTB Data Direction Register 1111 1111 1111 1111
81h, 181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.
Pan. enghera‘ Se‘ed WR Pan x i WF! Tms x
2002 Microchip Technology Inc. DS30325B-page 35
PIC16F7X
4.3 PORTC and the TRISC Register
PORTC is an 8-bit wide, bi-directional port. The corre-
sponding 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 is multiplexed with several peripheral functions
(Table 4-5). PORTC pins have Schmitt Trigger input
buffers.
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-modify-write instructions (BSF, BCF, XORWF)
with TRISC as destination should be avoided. The user
should refer to the corresponding peripheral section for
the correct TRIS bit settings, and to Section 13.1 for
additional information on read-modify-write operations.
FIGURE 4-5: PORTC BLOCK DIAGRAM
(PERIPHERAL OUTPUT
OVERRIDE)
TABLE 4-5: PORTC FUNCTIONS
TABLE 4-6: SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Port/Peripheral Select(2)
Data Bus
WR Port
WR TRIS
RD Port
Data Latch
TRIS Latch
RD TRIS Schmitt
Trigger
QD
Q
CK
QD
EN
Peripheral Data Out 0
1
QD
Q
CK
P
N
VDD
VSS
Peripheral
OE(3)
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.
I/O
pin(1)
Name Bit# Buffer Type Function
RC0/T1OSO/T1CKI bit0 ST Input/output port pin or Timer1 oscillator output/Timer1 clock input.
RC1/T1OSI/CCP2 bit1 ST Input/output port pin or Timer1 oscillator input or Capture2
input/Compare2 output/PWM2 output.
RC2/CCP1 bit2 ST Input/output port pin or Capture1 input/Compare1 output/PWM1 output.
RC3/SCK/SCL bit3 ST RC3 can also be the synchronous serial clock for both SPI and I2C
modes.
RC4/SDI/SDA bit4 ST RC4 can also be the SPI Data In (SPI mode) or Data I/O (I2C mode).
RC5/SDO bit5 ST Input/output port pin or Synchronous Serial Port data output.
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
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
07h PORTC RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0 xxxx xxxx uuuu uuuu
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
Legend: x = unknown, u = unchanged
RD TRIS J
PIC16F7X
DS30325B-page 36 2002 Microchip Technology Inc.
4.4 PORTD and TRISD Registers
This section is not applicable to the PIC16F73 or
PIC16F76.
PORTD is an 8-bit port with Schmitt Trigger input buff-
ers. Each pin is individually configureable as an input or
output.
PORTD can be configured as an 8-bit wide micro-
processor port (parallel slave port) by setting control bit
PSPMODE (TRISE<4>). In this mode, the input buffers
are TTL.
FIGURE 4-6: PORTD BLOCK DIAGRAM
(IN I/O PORT MODE)
TABLE 4-7: PORTD FUNCTIONS
TABLE 4-8: SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Data Bus
WR Port
WR TRIS
RD Port
Data Latch
TRIS Latch
RD TRIS
Schmitt
Trigger
Input
Buffer
I/O pin(1)
Note 1: I/O pins have protection diodes to VDD and VSS.
QD
CK
QD
CK
EN
QD
EN
Name Bit# Buffer Type Function
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: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
08h PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 xxxx xxxx uuuu uuuu
88h TRISD PORTD Data Direction Register 1111 1111 1111 1111
89h TRISE IBF OBF IBOV PSPMODE PORTE Data Direction bits 0000 -111 0000 -111
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PORTD.
HD Pan
2002 Microchip Technology Inc. DS30325B-page 37
PIC16F7X
4.5 PORTE and TRISE Register
This section is not applicable to the PIC16F73 or
PIC16F76.
PORTE has three pins, RE0/RD/AN5, RE1/WR/AN6
and RE2/CS/AN7, which are individually configureable
as inputs or outputs. These pins have Schmitt Trigger
input buffers.
I/O PORTE becomes control inputs for the micro-
processor 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.
Register 4-1 shows the TRISE register, which also con-
trols the parallel slave port operation.
PORTE pins are multiplexed with analog inputs. When
selected as an analog input, these pins will read as 0s.
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.
FIGURE 4-7: PORTE BLOCK DIAGRAM
(IN I/O PORT MODE)
Note: On a Power-on Reset, these pins are con-
figured as analog inputs and read as 0.
Data Bus
WR Port
WR TRIS
RD Port
Data Latch
TRIS Latch
RD TRIS
Schmitt
Trigger
Input
Buffer
I/O pin(1)
Note 1: I/O pins have protection diodes to VDD and VSS.
QD
CK
QD
CK
EN
QD
EN
Farallel Slave Porl Slams/Control bits: FORTE Dala Direclion bils:
PIC16F7X
DS30325B-page 38 2002 Microchip Technology Inc.
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'
bit 2 PORTE Data Direction bits:
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:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
2002 Microchip Technology Inc. DS30325B-page 39
PIC16F7X
TABLE 4-9: PORTE FUNCTIONS
TABLE 4-10: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
Name 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.
For RD (PSP mode):
1 = IDLE
0 = Read operation. Contents of PORTD register output to PORTD I/O
pins (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.
For WR (PSP mode):
1 =IDLE
0 = Write operation. Value of PORTD I/O pins latched into 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.
For CS (PSP mode):
1 = Device is not selected
0 = Device is selected
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
Addr 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
09h PORTE — — — RE2 RE1 RE0 ---- -xxx ---- -uuu
89h TRISE IBF OBF IBOV PSPMODE PORTE Data Direction bits 0000 -111 0000 -111
9Fh ADCON1 PCFG2 PCFG1 PCFG0 ---- -000 ---- -000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PORTE.
PIC16F7X
DS30325B-page 40 2002 Microchip Technology Inc.
4.6 Parallel Slave Port
The Parallel Slave Port (PSP) is not implemented on
the PIC16F73 or PIC16F76.
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 an external system using the
read control input pin RE0/RD, the write control input
pin RE1/WR, and the chip select control input pin
RE2/CS.
The PSP can directly interface to an 8-bit micro-
processor 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 cor-
responding data direction bits of the TRISE register
(TRISE<2:0>) must be configured as inputs (i.e., 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
(external reads) and one for data input (external
writes). The firmware writes 8-bit data to the PORTD
output data latch and reads data from the PORTD input
data latch (note that they have the same address). In
this mode, the TRISD register is ignored, since the
external device is controlling the direction of data flow.
An external write to the PSP occurs when the CS and
WR lines are both detected low. Firmware can read the
actual data on the PORTD pins during this time. When
either the CS or WR lines become high (level trig-
gered), the data on the PORTD pins is latched, and the
Input Buffer Full (IBF) status flag bit (TRISE<7>) and
interrupt flag bit PSPIF (PIR1<7>) are set on the Q4
clock cycle, following the next Q2 cycle to signal the
write is complete (Figure 4-9). Firmware clears the IBF
flag by reading the latched PORTD data, and clears the
PSPIF bit.
The Input Buffer Overflow (IBOV) status flag bit
(TRISE<5>) is set if an external write to the PSP occurs
while the IBF flag is set from a previous external write.
The previous PORTD data is overwritten with the new
data. IBOV is cleared by reading PORTD and clearing
IBOV.
A read from the PSP occurs when both the CS and RD
lines are detected low. The data in the PORTD output
latch is output to the PORTD pins. The Output Buffer
Full (OBF) status flag bit (TRISE<6>) is cleared imme-
diately (Figure 4-10), indicating that the PORTD latch is
being read, or has been read by the external bus. If
firmware writes new data to the output latch during this
time, it is immediately output to the PORTD pins, but
OBF will remain cleared.
When either the CS or RD pins are detected high, the
PORTD outputs are disabled, and 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 firmware writes new data to PORTD.
When not in PSP mode, the IBF and OBF bits are held
clear. Flag bit IBOV remains unchanged. The PSPIF bit
must be cleared by the user in firmware; the interrupt
can be disabled by clearing the interrupt enable bit
PSPIE (PIE1<7>).
FIGURE 4-8: PORTD AND PORTE
BLOCK DIAGRAM
(PARALLEL SLAVE PORT)
Data Bus
WR
Port
RD
RDx
QD
CK
EN
QD
EN
Port
pin
One bit of PORTD
Set Interrupt Flag
PSPIF (PIR1<7>)
Read
Chip Select
Write
RD
CS
WR
Note: I/O pin has protection diodes to VDD and VSS.
TTL
TTL
TTL
TTL
2002 Microchip Technology Inc. DS30325B-page 41
PIC16F7X
FIGURE 4-9: PARALLEL SLAVE PORT WRITE WAVEFORMS
FIGURE 4-10: PARALLEL SLAVE PORT READ WAVEFORMS
TABLE 4-11: REGISTERS ASSOCIATED WITH PARALLEL SLAVE PORT
Q1 Q2 Q3 Q4
CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
WR
RD
IBF
OBF
PSPIF
PORTD<7:0>
Q1 Q2 Q3 Q4
CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
WR
IBF
PSPIF
RD
OBF
PORTD<7:0>
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
08h PORTD Port data latch when written: Port pins when read xxxx xxxx uuuu uuuu
09h PORTE — — RE2 RE1 RE0 ---- -xxx ---- -uuu
89h TRISE IBF OBF IBOV PSPMODE PORTE Data Direction Bits 0000 -111 0000 -111
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
9Fh ADCON1 PCFG2 PCFG1 PCFG0 ---- -000 ---- -000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Parallel Slave Port.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16F73/76; always maintain these bits clear.
PIC16F7X
DS30325B-page 42 2002 Microchip Technology Inc.
NOTES:
fiD r7777, iiiiiii L777”, 7777777
2002 Microchip Technology Inc. DS30325B-page 43
PIC16F7X
5.0 TIMER0 MODULE
The Timer0 module timer/counter has the following
features:
8-bit timer/counter
Readable and writable
8-bit software programmable prescaler
Internal or external clock select
Interrupt on overflow from FFh to 00h
Edge select for external clock
Additional information on the Timer0 module is avail-
able in the PICmicro Mid-Range MCU Family Refer-
ence Manual (DS33023).
Figure 5-1 is a block diagram of the Timer0 module and
the prescaler shared with the WDT.
Timer0 operation is controlled through the
OPTION_REG register (Register 5-1 on the following
page). Timer mode is selected by clearing bit T0CS
(OPTION_REG<5>). In Timer mode, the Timer0 mod-
ule will increment every instruction cycle (without pres-
caler). 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.
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 ris-
ing edge. Restrictions on the external clock input are
discussed in detail in Section 5.2.
The prescaler is mutually exclusively shared between
the Timer0 module and the Watchdog Timer. The pres-
caler is not readable or writable. Section 5.3 details the
operation of the prescaler.
5.1 Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0 reg-
ister overflows from FFh to 00h. This overflow sets bit
TMR0IF (INTCON<2>). The interrupt can be masked
by clearing bit TMR0IE (INTCON<5>). Bit TMR0IF
must be cleared in software by the Timer0 module
Interrupt Service Routine, before re-enabling this inter-
rupt. The TMR0 interrupt cannot awaken the processor
from SLEEP, since the timer is shut-off during SLEEP.
FIGURE 5-1: BLOCK DIAGRAM OF THE TIMER0 MODULE AND PRESCALER
RA4/T0CKI
T0SE
pin
M
U
X
CLKOUT (= FOSC/4)
SYNC
2
Cycles TMR0 reg
8-bit Prescaler
8 - to - 1MUX
M
U
X
M U X
Watchdog
Timer
PSA
01
0
1
WDT
Time-out
PS2:PS0
8
Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION_REG<5:0>).
PSA
WDT Enable bit
M
U
X
0
10
1
Data Bus
Set Flag bit TMR0IF
on Overflow
8
PSA
T0CS
PRESCALER
PIC16F7X
DS30325B-page 44 2002 Microchip Technology Inc.
5.2 Using Timer0 with an External
Clock
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 accom-
plished 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 2Tosc (and
a small RC delay of 20 ns) and low for at least 2Tosc
(and a small RC delay of 20 ns). Refer to the electrical
specification of the desired device.
REGISTER 5-1: 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: PORTB Pull-up Enable bit (see Section 2.2.2.2)
bit 6 INTEDG: Interrupt Edge Select bit (see Section 2.2.2.2)
bit 5 T0CS: TMR0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKOUT)
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
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
000
001
010
011
100
101
110
111
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
Bit Value TMR0 Rate WDT Rate
Note: To avoid an unintended device RESET, the instruction sequences shown in
Example 5-1 and Example 5-2 (page 45) must be executed when changing the pres-
caler assignment between Timer0 and the WDT. This sequence must be followed
even if the WDT is disabled.
2002 Microchip Technology Inc. DS30325B-page 45
PIC16F7X
5.3 Prescaler
There is only one prescaler available on the microcon-
troller; it is shared exclusively between the Timer0
module and the Watchdog Timer. The usage of the
prescaler is also mutually exclusive: that is, 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.
Examples of code for assigning the prescaler assign-
ment are shown in Example 5-1 and Example 5-2.
Note that when the prescaler is being assigned to the
WDT with ratios other than 1:1, lines 2 and 3 (high-
lighted) are optional. If a prescale ratio of 1:1 is to used,
however, these lines must be used to set a temporary
value. The final 1:1 value is then set in lines 10 and 11
(highlighted). (Line numbers are included in the exam-
ple for illustrative purposes only, and are not part of the
actual code.)
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g. CLRF 1, MOVWF 1,
BSF 1,x....etc.) will clear the prescaler. When assigned
to WDT, a CLRWDT instruction will clear the prescaler
along with the Watchdog Timer.
EXAMPLE 5-1: CHANGING THE PRESCALER ASSIGNMENT FROM TIMER0 TO WDT
EXAMPLE 5-2: CHANGING THE PRESCALER ASSIGNMENT FROM WDT TO TIMER0
TABLE 5-1: REGISTERS ASSOCIATED WITH TIMER0
Note: Writing to TMR0 when the prescaler is
assigned to Timer0, will clear the prescaler
count but will not change the prescaler
assignment.
1) BSF STATUS, RP0 ; Bank1
2) MOVLW b’xx0x0xxx’ ; Select clock source and prescale value of
3) MOVWF OPTION_REG ; other than 1:1
4) BCF STATUS, RP0 ; Bank0
5) CLRF TMR0 ; Clear TMR0 and prescaler
6) BSF STATUS, RP1 ; Bank1
7) MOVLW b’xxxx1xxx’ ; Select WDT, do not change prescale value
8) MOVWF OPTION_REG
9) CLRWDT ; Clears WDT and prescaler
10) MOVLW b’xxxx1xxx’ ; Select new prescale value and WDT
11) MOVWF OPTION_REG
12) BCF STATUS, RP0 ; Bank0
CLRWDT ; Clear WDT and prescaler
BSF STATUS, RP0 ; Bank1
MOVLW b’xxxx0xxx’ ; Select TMR0, new prescale
MOVWF OPTION_REG ; value and clock source
BCF STATUS, RP0 ; Bank0
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
01h,101h TMR0 Timer0 Module Register xxxx xxxx uuuu uuuu
0Bh,8Bh,
10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
81h,181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented locations read as 0. Shaded cells are not used by Timer0.
PIC16F7X
DS30325B-page 46 2002 Microchip Technology Inc.
NOTES:
TMRTCS:1. TMRTCS : 0.
2002 Microchip Technology Inc. DS30325B-page 47
PIC16F7X
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>).
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 as the special event trigger (see Sections 8.1
and 8.2). Register 6-1 shows the Timer1 Control
register.
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI/CCP2 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).
REGISTER 6-1: T1CON: TIMER1 CONTROL REGISTER (ADDRESS 10h)
U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON
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
TMR1CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
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 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 reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
PIC16F7X
DS30325B-page 48 2002 Microchip Technology Inc.
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.
6.2 Timer1 Counter Operation
Timer1 may operate in Asynchronous or Synchronous
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.
FIGURE 6-1: TIMER1 INCREMENTING EDGE
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/CCP2, when bit
T1OSCEN is set, or on pin RC0/T1OSO/T1CKI, when
bit T1OSCEN is cleared.
If T1SYNC is cleared, then the external clock input is
synchronized with internal phase clocks. The synchro-
nization is done after the prescaler stage. The pres-
caler 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.
FIGURE 6-2: TIMER1 BLOCK DIAGRAM
T1CKI
(Default high)
T1CKI
(Default low)
Note: Arrows indicate counter increments.
TMR1H TMR1L
T1OSC T1SYNC
TMR1CS
T1CKPS1:T1CKPS0 Q Clock
T1OSCEN
Enable
Oscillator(1)
FOSC/4
Internal
Clock
TMR1ON
On/Off
Prescaler
1, 2, 4, 8
Synchronize
det
1
0
0
1
Synchronized
Clock Input
2
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2(2)
Note 1: When the T1OSCEN bit is cleared, the inverter is turned off. This eliminates power drain.
2: For the PIC16F73/76, the Schmitt Trigger is not implemented in External Clock mode.
Set Flag bit
TMR1IF on
Overflow TMR1
(2)
2002 Microchip Technology Inc. DS30325B-page 49
PIC16F7X
6.4 Timer1 Operation in
Asynchronous Counter Mode
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 soft-
ware are needed to read/write the timer (Section 6.4.1).
In Asynchronous Counter mode, Timer1 cannot be
used as a time-base for capture or compare operations.
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 conten-
tion 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. The
example code provided in Example 6-1 and
Example 6-2 demonstrates how to write to and read
Timer1 while it is running in Asynchronous mode.
EXAMPLE 6-1: WRITING A 16-BIT FREE-RUNNING TIMER
EXAMPLE 6-2: READING A 16-BIT FREE-RUNNING TIMER
; All interrupts are disabled
CLRF TMR1L ; Clear Low byte, Ensures no rollover into TMR1H
MOVLW HI_BYTE ; Value to load into TMR1H
MOVWF TMR1H, F ; Write High byte
MOVLW LO_BYTE ; Value to load into TMR1L
MOVWF TMR1H, F ; Write Low byte
; Re-enable the Interrupt (if required)
CONTINUE ; Continue with your code
; All interrupts are disabled
MOVF TMR1H, W ; Read high byte
MOVWF TMPH
MOVF TMR1L, W ; Read low byte
MOVWF TMPL
MOVF TMR1H, W ; Read high byte
SUBWF TMPH, W ; Sub 1st read with 2nd read
BTFSC STATUS,Z ; Is result = 0
GOTO CONTINUE ; Good 16-bit read
; TMR1L may have rolled over between the read of the high and low bytes.
; Reading the high and low bytes now will read a good value.
MOVF TMR1H, W ; Read high byte
MOVWF TMPH
MOVF TMR1L, W ; Read low byte
MOVWF TMPL ; Re-enable the Interrupt (if required)
CONTINUE ; Continue with your code
PIC16F7X
DS30325B-page 50 2002 Microchip Technology Inc.
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 oscilla-
tor 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.
The Timer1 oscillator is identical to the LP oscillator.
The user must provide a software time delay to ensure
proper oscillator start-up.
6.6 Resetting Timer1 using a CCP
Trigger Output
If the CCP1 or CCP2 module is configured in Compare
mode to generate a special event trigger
(CCP1M3:CCP1M0 = 1011), this signal will reset
Timer1.
Timer1 must be configured for either Timer or Synchro-
nized 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 spe-
cial event trigger from CCP1 or CCP2, the write will
take precedence.
In this mode of operation, the CCPRxH:CCPRxL regis-
ter pair effectively becomes the period register for
Timer1.
6.7 Resetting of Timer1 Register Pair
(TMR1H, TMR1L)
TMR1H and TMR1L registers are not reset to 00h on a
POR, or any other RESET, except by the CCP1 and
CCP2 special event triggers.
TABLE 6-1: CAPACITOR SELECTION FOR
THE TIMER1 OSCILLATOR
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.
6.8 Timer1 Prescaler
The prescaler counter is cleared on writes to the
TMR1H or TMR1L registers.
TABLE 6-2: REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Note: The special event triggers from the CCP1
and CCP2 modules will not set interrupt
flag bit TMR1IF (PIR1<0>).
Osc Type Frequency Capacitors Used:
OSC1 OSC2
LP 32 kHz 47 pF 47 pF
100 kHz 33 pF 33 pF
200 kHz 15 pF 15 pF
Capacitor values are for design guidance only.
These capacitors were tested with the crystals listed
below for basic start-up and operation. These values
were not optimized.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
VDD and temperature range for the application.
See the notes (below) table for additional information.
Commonly Used Crystals:
32.768 kHz Epson C-001R32.768K-A
100 kHz Epson C-2 100.00 KC-P
200 kHz STD XTL 200.000 kHz
Note 1: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
2: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appro-
priate values of external components.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
0Bh,8Bh,
10Bh,18Bh
INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
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 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer1 module.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16F73/76; always maintain these bits clear.
2002 Microchip Technology Inc. DS30325B-page 51
PIC16F7X
7.0 TIMER2 MODULE
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 reg-
ister is readable and writable, and is cleared on any
device RESET.
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>).
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.
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>)).
Timer2 can be shut-off by clearing control bit TMR2ON
(T2CON<2>) to minimize power consumption.
Register 7-1 shows the Timer2 control register.
Additional information on timer modules is available in
the PICmicro Mid-Range MCU Family Reference
Manual (DS33023).
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)
TMR2 is not cleared when T2CON is written.
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.
FIGURE 7-1: TIMER2 BLOCK DIAGRAM
Comparator
TMR2
Sets Flag
TMR2 reg
Output(1)
Reset
Postscaler
Prescaler
PR2 reg
2
FOSC/4
1:1, 1:4, 1:16
EQ
4
bit TMR2IF
Note 1: TMR2 register output can be software selected by the
SSP module as a baud clock.
1:1 to 1:16
T2OUTPS3:
T2OUTPS0
T2CKPS1:
T2CKPS0
PIC16F7X
DS30325B-page 52 2002 Microchip Technology Inc.
REGISTER 7-1: T2CON: TIMER2 CONTROL REGISTER (ADDRESS 12h)
TABLE 7-1: REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
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 reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
0Bh,8Bh,
10Bh, 18Bh
INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
11h TMR2 Timer2 Module Register 0000 0000 0000 0000
12h T2CON TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
92h PR2 Timer2 Period Register 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer2 module.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16F73/76; always maintain these bits clear.
2002 Microchip Technology Inc. DS30325B-page 53
PIC16F7X
8.0 CAPTURE/COMPARE/PWM
MODULES
Each Capture/Compare/PWM (CCP) module contains
a 16-bit register which can operate as a:
16-bit Capture register
16-bit Compare register
PWM Master/Slave Duty Cycle register
Both the CCP1 and CCP2 modules are identical in
operation, with the exception being the operation of the
special event trigger. Table 8-1 and Table 8-2 show the
resources and interactions of the CCP module(s). In
the following sections, the operation of a CCP module
is described with respect to CCP1. CCP2 operates the
same as CCP1, except where noted.
8.1 CCP1 Module
Capture/Compare/PWM Register1 (CCPR1) is com-
prised 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 clear both
TMR1H and TMR1L registers.
8.2 CCP2 Module
Capture/Compare/PWM Register1 (CCPR1) is com-
prised of two 8-bit registers: CCPR1L (low byte) and
CCPR1H (high byte). The CCP2CON register controls
the operation of CCP2. The special event trigger is
generated by a compare match; it will clear both
TMR1H and TMR1L registers, and start an A/D conver-
sion (if the A/D module is enabled).
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: CCP MODE - TIMER
RESOURCES REQUIRED
TABLE 8-2: INTERACTION OF TWO CCP MODULES
CCP Mode Timer Resource
Capture
Compare
PWM
Timer1
Timer1
Timer2
CCPx Mode CCPy Mode Interaction
Capture Capture Same TMR1 time-base.
Capture Compare Same TMR1 time-base.
Compare Compare Same TMR1 time-base.
PWM PWM The PWMs will have the same frequency and update rate (TMR2 interrupt).
The rising edges are aligned.
PWM Capture None.
PWM Compare None.
Cagture mode. Comgave mode. PWM mode.
PIC16F7X
DS30325B-page 54 2002 Microchip Technology Inc.
REGISTER 8-1: CCP1CON REGISTER/CCP2CON REGISTER (ADDRESS: 17h/1Dh)
U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CCPxX CCPxY CCPxM3 CCPxM2 CCPxM1 CCPxM0
bit 7 bit 0
bit 7-6 Unimplemented: Read as '0'
bit 5-4 CCPxX:CCPxY: 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 CCPRxL.
bit 3-0 CCPxM3:CCPxM0: CCPx Mode Select bits
0000 = Capture/Compare/PWM disabled (resets CCPx 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 (CCPxIF bit is set)
1001 = Compare mode, clear output on match (CCPxIF bit is set)
1010 = Compare mode, generate software interrupt on match (CCPxIF bit is set, CCPx pin is
unaffected)
1011 = Compare mode, trigger special event (CCPxIF bit is set, CCPx pin is unaffected);
CCP1 clears Timer1; CCP2 clears Timer1 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 reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
2002 Microchip Technology Inc. DS30325B-page 55
PIC16F7X
8.3 Capture Mode
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 fol-
lowing and is configured by CCPxCON<3:0>:
Every falling edge
Every rising edge
Every 4th rising edge
Every 16th rising edge
An event is selected by control bits CCP1M3:CCP1M0
(CCP1CON<3:0>). When a capture is made, the inter-
rupt 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
captured value.
8.3.1 CCP PIN CONFIGURATION
In Capture mode, the RC2/CCP1 pin should be config-
ured as an input by setting the TRISC<2> bit.
FIGURE 8-1: CAPTURE MODE
OPERATION BLOCK
DIAGRAM
8.3.2 TIMER1 MODE SELECTION
Timer1 must be running in Timer mode or Synchro-
nized Counter mode for the CCP module to use the
capture feature. In Asynchronous Counter mode, the
capture operation may not work.
8.3.3 SOFTWARE INTERRUPT
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.
8.3.4 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.
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 recom-
mended method for switching between capture pres-
calers. This example also clears the prescaler counter
and will not generate the false interrupt.
EXAMPLE 8-1: CHANGING BETWEEN
CAPTURE PRESCALERS
8.4 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
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.
FIGURE 8-2: COMPARE MODE
OPERATION BLOCK
DIAGRAM
Note: If the RC2/CCP1 pin is configured as an
output, a write to the port can cause a
capture condition.
CCPR1H CCPR1L
TMR1H TMR1L
Set Flag bit CCP1IF
(PIR1<2>)
Capture
Enable
QsCCP1CON<3:0>
RC2/CCP1
Prescaler
÷ 1, 4, 16
and
Edge Detect
pin
CLRF CCP1CON ;Turn CCP module off
MOVLW NEW_CAPT_PS ;Load the W reg with
;the new prescaler
;move value and CCP ON
MOVWF CCP1CON ;Load CCP1CON with this
;value
CCPR1H CCPR1L
TMR1H TMR1L
Comparator
QS
R
Output
Logic
Special Event Trigger
Set Flag bit CCP1IF
(PIR1<2>)
Match
RC2/CCP1
TRISC<2>
CCP1CON<3:0>
Mode Select
Output Enable
Pin
Special Event Trigger will:
clear TMR1H and TMR1L registers
NOT set interrupt flag bit TMR1F (PIR1<0>)
(for CCP2 only) set the GO/DONE bit (ADCON0<2>)
PIC16F7X
DS30325B-page 56 2002 Microchip Technology Inc.
8.4.1 CCP PIN CONFIGURATION
The user must configure the RC2/CCP1 pin as an out-
put by clearing the TRISC<2> bit.
8.4.2 TIMER1 MODE SELECTION
Timer1 must be running in Timer mode or Synchro-
nized Counter mode if the CCP module is using the
compare feature. In Asynchronous Counter mode, the
compare operation may not work.
8.4.3 SOFTWARE INTERRUPT MODE
When Generate Software Interrupt mode is chosen, the
CCP1 pin is not affected. The CCP1IF or CCP2IF bit is
set, causing a CCP interrupt (if enabled).
8.4.4 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. This allows the CCPR1 register to
effectively be a 16-bit programmable period register for
Timer1.
The special event trigger output of CCP2 resets the
TMR1 register pair and starts an A/D conversion (if the
A/D module is enabled).
TABLE 8-3: REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, AND TIMER1
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.
Note: The special event trigger from the CCP1
and CCP2 modules will not set interrupt
flag bit TMR1IF (PIR1<0>).
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
0Bh,8Bh,
10Bh,18Bh
INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
0Dh PIR2 CCP2IF ---- ---0 ---- ---0
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
8Dh PIE2 CCP2IE ---- ---0 ---- ---0
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 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu
15h CCPR1L Capture/Compare/PWM Register1 (LSB) xxxx xxxx uuuu uuuu
16h CCPR1H Capture/Compare/PWM Register1 (MSB) xxxx xxxx uuuu uuuu
17h CCP1CON CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
1Bh CCPR2L Capture/Compare/PWM Register2 (LSB) xxxx xxxx uuuu uuuu
1Ch CCPR2H Capture/Compare/PWM Register2 (MSB) xxxx xxxx uuuu uuuu
1Dh CCP2CON CCP2X CCP2Y CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by Capture and Timer1.
Note 1: The PSP is not implemented on the PIC16F73/76; always maintain these bits clear.
2002 Microchip Technology Inc. DS30325B-page 57
PIC16F7X
8.5 PWM Mode (PWM)
In Pulse Width Modulation mode, the CCPx pin pro-
duces 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.
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 8.5.3.
FIGURE 8-3: SIMPLIFIED PWM BLOCK
DIAGRAM
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
8.5.1 PWM PERIOD
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
8.5.2 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 glitchless PWM operation.
When the CCPR1H and 2-bit latch match TMR2, con-
catenated 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:
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.
CCPR1L
CCPR1H (Slave)
Comparator
TMR2
Comparator
PR2
(1)
RQ
S
Duty Cycle Registers CCP1CON<5:4>
Clear Timer,
CCP1 pin and
latch D.C.
TRISC<2>
RC2/CCP1
(Note 1)
Note 1: The 8-bit timer is concatenated with the 2-bit inter-
nal Q clock or the 2 bits of the prescaler to create the
10-bit time-base.
Period
Duty Cycle
TMR2 = PR2
TMR2 = Duty Cycle
TMR2 = PR2
TMR2
RESET TMR2
RESET
Note: The Timer2 postscaler (see Section 8.3) is
not used in the determination of the PWM
frequency. The postscaler could be used to
have a servo update rate at a different fre-
quency than the PWM output.
Note: If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
log(FPWM
log(2)
FOSC )bits
=
Resolution
PIC16F7X
DS30325B-page 58 2002 Microchip Technology Inc.
8.5.3 SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the CCP module for PWM operation:
1. Set the PWM period by writing to the PR2 register.
2. Set the PWM duty cycle by writing to the
CCPR1L register and CCP1CON<5:4> bits.
3. Make the CCP1 pin an output by clearing the
TRISC<2> bit.
4. Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
5. Configure the CCP1 module for PWM operation.
TABLE 8-4: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
TABLE 8-5: REGISTERS ASSOCIATED WITH PWM AND TIMER2
PWM Frequency 1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
Timer Prescale (1, 4, 16) 16 4 1 1 1 1
PR2 Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 10 10 10 8 7 5.5
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
0Bh,8Bh,
10Bh,18Bh
INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
0Dh PIR2 — — — — CCP2IF ---- ---0 ---- ---0
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
8Dh PIE2 — — — — CCP2IE ---- ---0 ---- ---0
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
11h TMR2 Timer2 Module Register 0000 0000 0000 0000
92h PR2 Timer2 Module Period Register 1111 1111 1111 1111
12h T2CON TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
15h CCPR1L Capture/Compare/PWM Register1 (LSB) xxxx xxxx uuuu uuuu
16h CCPR1H Capture/Compare/PWM Register1 (MSB) xxxx xxxx uuuu uuuu
17h CCP1CON CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
1Bh CCPR2L Capture/Compare/PWM Register2 (LSB) xxxx xxxx uuuu uuuu
1Ch CCPR2H Capture/Compare/PWM Register2 (MSB) xxxx xxxx uuuu uuuu
1Dh CCP2CON CCP2X CCP2Y CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PWM and Timer2.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16F73/76; always maintain these bits clear.
2002 Microchip Technology Inc. DS30325B-page 59
PIC16F7X
9.0 SYNCHRONOUS SERIAL PORT
(SSP) MODULE
9.1 SSP Module Overview
The Synchronous Serial Port (SSP) module is a serial
interface useful for communicating with other periph-
eral or microcontroller devices. These peripheral
devices may be Serial EEPROMs, shift registers, dis-
play drivers, A/D converters, etc. The SSP module can
operate in one of two modes:
Serial Peripheral Interface (SPI)
Inter-Integrated Circuit (I2C)
An overview of I2C operations and additional informa-
tion on the SSP module can be found in the PICmicro
Mid-Range MCU Family Reference Manual
(DS33023).
Refer to Application Note AN578, Use of the SSP
Module in the I 2C Multi-Master Environment
(DS00578).
9.2 SPI Mode
This section contains register definitions and opera-
tional characteristics of the SPI module. Additional
information on the SPI module can be found in the
PICmicro Mid-Range MCU Family Reference Man-
ual (DS33023A).
SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. To accom-
plish communication, typically three pins are used:
Serial Data Out (SDO) RC5/SDO
Serial Data In (SDI) RC4/SDI/SDA
Serial Clock (SCK) RC3/SCK/SCL
Additionally, a fourth pin may be used when in a Slave
mode of operation:
Slave Select (SS) RA5/SS/AN4
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits in the SSPCON register (SSPCON<5:0>)
and SSPSTAT<7:6>. These control bits allow the fol-
lowing to be specified:
Master mode (SCK is the clock output)
Slave mode (SCK is the clock input)
Clock Polarity (IDLE state of SCK)
Clock edge (output data on rising/falling edge of
SCK)
Clock Rate (Master mode only)
Slave Select mode (Slave mode only)
SP‘ Master mode. SFI Slave mode. ‘20 mode. SPI mode CKF : 0. SPI mode CKF : . \ZC mode. Receive SFI and ‘20 modes . Transmit IZC mode on‘y .
PIC16F7X
DS30325B-page 60 2002 Microchip Technology Inc.
REGISTER 9-1: SSPSTAT: SYNC SERIAL PORT STATUS REGISTER (ADDRESS 94h)
R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0
SMP CKE D/A PSR/WUA BF
bit 7 bit 0
bit 7 SMP: SPI Data Input Sample Phase bit
SPI Master mode:
1 = Input data sampled at end of data output time
0 = Input data sampled at middle of data output time (Microwire®)
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode
I2 C mode:
This bit must be maintained clear
bit 6 CKE: SPI Clock Edge Select bit (Figure 9-2, Figure 9-3, and Figure 9-4)
SPI mode, CKP = 0:
1 = Data transmitted on rising edge of SCK (Microwire® alternate)
0 = Data transmitted on falling edge of SCK
SPI mode, CKP = 1:
1 = Data transmitted on falling edge of SCK (Microwire® default)
0 = Data transmitted on rising edge of SCK
I2 C mode:
This bit must be maintained clear
bit 5 D/A: Data/Address bit (I2C mode only)
1 = Indicates that the last byte received or transmitted was data
0 = Indicates that the last byte received or transmitted was address
bit 4 P: STOP bit (I2C mode only)
This bit is cleared when the SSP module is disabled, or when the START bit is detected last.
SSPEN is cleared.
1 = Indicates that a STOP bit has been detected last (this bit is 0 on RESET)
0 = STOP bit was not detected last
bit 3 S: START bit (I2C mode only)
This bit is cleared when the SSP module is disabled, or when the STOP bit is detected last.
SSPEN is cleared.
1 = Indicates that a START bit has been detected last (this bit is 0 on RESET)
0 = START bit was not detected last
bit 2 R/W: Read/Write bit Information (I2C mode only)
This bit holds the R/W bit information following the last address match. This bit is only valid from
the address match to the next START bit, STOP bit, or ACK bit.
1 = Read
0 = Write
bit 1 UA: Update Address bit (10-bit I2C mode only)
1 = Indicates that the user needs to update the address in the SSPADD register
0 = Address does not need to be updated
bit 0 BF: Buffer Full Status bit
Receive (SPI and I2 C modes):
1 = Receive complete, SSPBUF is full
0 = Receive not complete, SSPBUF is empty
Transmit (I2 C mode only):
1 = Transmit in progress, SSPBUF is full
0 = Transmit complete, SSPBUF is empty
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
\n SP‘ mode. \n ‘20 mode. \n SP‘ mode. \n ‘20 mode. \n SP‘ mode. \n ‘20 mode.
2002 Microchip Technology Inc. DS30325B-page 61
PIC16F7X
REGISTER 9-2: SSPCON: SYNC SERIAL PORT CONTROL REGISTER (ADDRESS 14h)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0
bit 7 bit 0
bit 7 WCOL: Write Collision Detect bit
1 = The SSPBUF register is written while it is still transmitting the previous word
(must be cleared in software)
0 = No collision
bit 6 SSPOV: Receive Overflow Indicator bit
In SPI mode:
1 = A new byte is received while the SSPBUF register is still holding the previous data. In case
of overflow, the data in SSPSR is lost. Overflow can only occur in Slave mode. The user
must read the SSPBUF, even if only transmitting data, to avoid setting overflow. In
Master mode, the overflow bit is not set since each new reception (and transmission) is
initiated by writing to the SSPBUF register.
0 = No overflow
In I2 C mode:
1 = A byte is received while the SSPBUF register is still holding the previous byte. SSPOV
is a dont care in Transmit mode. SSPOV must be cleared in software in either mode.
0 = No overflow
bit 5 SSPEN: Synchronous Serial Port Enable bit
In SPI mode:
1 = Enables serial port and configures SCK, SDO, and SDI as serial port pins
0 = Disables serial port and configures these pins as I/O port pins
In I2 C mode:
1 = Enables the serial port and configures the SDA and SCL pins as serial port pins
0 = Disables serial port and configures these pins as I/O port pins
In both modes, when enabled, these pins must be properly configured as input or output.
bit 4 CKP: Clock Polarity Select bit
In SPI mode:
1 = IDLE state for clock is a high level (Microwire® default)
0 = IDLE state for clock is a low level (Microwire® alternate)
In I2 C mode:
SCK release control
1 = Enable clock
0 = Holds clock low (clock stretch). (Used to ensure data setup time.)
bit 3-0 SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
0000 = SPI Master mode, clock = FOSC/4
0001 = SPI Master mode, clock = FOSC/16
0010 = SPI Master mode, clock = FOSC/64
0011 = SPI Master mode, clock = TMR2 output/2
0100 = SPI Slave mode, clock = SCK pin. SS pin control enabled.
0101 = SPI Slave mode, clock = SCK pin. SS pin control disabled. SS can be used as I/O pin.
0110 = I2C Slave mode, 7-bit address
0111 = I2C Slave mode, 10-bit address
1011 = I2C Firmware Controlled Master mode (slave IDLE)
1110 = I2C Slave mode, 7-bit address with START and STOP bit interrupts enabled
1111 = I2C Slave mode, 10-bit address with START and STOP bit interrupts enabled
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
PIC16F7X
DS30325B-page 62 2002 Microchip Technology Inc.
FIGURE 9-1: SSP BLOCK DIAGRAM
(SPI MODE)
To enable the serial port, SSP enable bit, SSPEN
(SSPCON<5>) must be set. To reset or reconfigure SPI
mode, clear bit SSPEN, re-initialize the SSPCON reg-
ister, and then set bit SSPEN. This configures the SDI,
SDO, SCK, and SS pins as serial port pins. For the pins
to behave as the serial port function, they must have
their data direction bits (in the TRISC register) appro-
priately programmed. That is:
SDI must have TRISC<4> set
SDO must have TRISC<5> cleared
SCK (Master mode) must have TRISC<3>
cleared
SCK (Slave mode) must have TRISC<3> set
SS must have TRISA<5> set and ADCON must
be configured such that RA5 is a digital I/O
.
Read Write
Internal
Data Bus
RC4/SDI/SDA
RC5/SDO
RA5/SS/AN4
RC3/SCK/
SSPSR reg
SSPBUF reg
SSPM3:SSPM0
bit0 Shift
Clock
SS Control
Enable
Edge
Select
Clock Select
TMR2 Output
TCY
Prescaler
4, 16, 64
TRISC<3>
2
Edge
Select
2
4
SCL
Peripheral OE
Note 1: When the SPI is in Slave mode with SS pin
control enabled (SSPCON<3:0> = 0100),
the SPI module will reset if the SS pin is set
to VDD.
2: If the SPI is used in Slave mode with
CKE = '1', then the SS pin control must be
enabled.
3: When the SPI is in Slave mode with SS
pin control enabled (SSPCON<3:0> =
0100), the state of the SS pin can affect
the state read back from the TRISC<5>
bit. The Peripheral OE signal from the
SSP module into PORTC controls the
state that is read back from the
TRISC<5> bit (see Section 4.3 for infor-
mation on PORTC). If Read-Modify-Write
instructions, such as BSF are performed
on the TRISC register while the SS pin is
high, this will cause the TRISC<5> bit to
be set, thus disabling the SDO output.
2002 Microchip Technology Inc. DS30325B-page 63
PIC16F7X
FIGURE 9-2: SPI MODE TIMING, MASTER MODE
FIGURE 9-3: SPI MODE TIMING (SLAVE MODE WITH CKE = 0)
FIGURE 9-4: SPI MODE TIMING (SLAVE MODE WITH CKE = 1)
SCK (CKP = 0,
SDI (SMP = 0)
SSPIF
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
SDI (SMP = 1)
SCK (CKP = 0,
SCK (CKP = 1,
SCK (CKP = 1,
SDO
bit7
bit7 bit0
bit0
CKE = 0)
CKE = 1)
CKE = 0)
CKE = 1)
SCK (CKP = 0)
SDI (SMP = 0)
SSPIF
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
SCK (CKP = 1)
SDO
bit7 bit0
SS (optional)
SCK (CKP = 0)
SDI (SMP = 0)
SSPIF
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
SCK (CKP = 1)
SDO
bit7 bit0
SS
PIC16F7X
DS30325B-page 64 2002 Microchip Technology Inc.
TABLE 9-1: REGISTERS ASSOCIATED WITH SPI OPERATION
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
0Bh,8Bh.
10Bh,18Bh
INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
85h TRISA PORTA Data Direction Register --11 1111 --11 1111
94h SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the SSP in SPI mode.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16F73/76; always maintain these bits clear.
2002 Microchip Technology Inc. DS30325B-page 65
PIC16F7X
9.3 SSP I2 C Operation
The SSP module in I2C mode, fully implements all slave
functions, except general call support, and provides
interrupts on START and STOP bits in hardware to facil-
itate firmware implementations of the master functions.
The SSP module implements the standard mode speci-
fications as well as 7-bit and 10-bit addressing.
Two pins are used for data transfer. These are the RC3/
SCK/SCL pin, which is the clock (SCL), and the RC4/
SDI/SDA pin, which is the data (SDA). The user must
configure these pins as inputs or outputs through the
TRISC<4:3> bits.
The SSP module functions are enabled by setting SSP
enable bit SSPEN (SSPCON<5>).
FIGURE 9-5: SSP BLOCK DIAGRAM
(I2C MODE)
The SSP module has five registers for I2C operation.
These are the:
SSP Control Register (SSPCON)
SSP Status Register (SSPSTAT)
Serial Receive/Transmit Buffer (SSPBUF)
SSP Shift Register (SSPSR) - Not directly accessible
SSP Address Register (SSPADD)
The SSPCON register allows control of the I2C opera-
tion. Four mode selection bits (SSPCON<3:0>) allow
one of the following I2C modes to be selected:
I2C Slave mode (7-bit address)
I2C Slave mode (10-bit address)
I2C Slave mode (7-bit address), with START and
STOP bit interrupts enabled to support Firmware
Master mode
I2C Slave mode (10-bit address), with START and
STOP bit interrupts enabled to support Firmware
Master mode
I2C START and STOP bit interrupts enabled to
support Firmware Master mode, Slave is IDLE
Selection of any I2C mode with the SSPEN bit set,
forces the SCL and SDA pins to be open drain, pro-
vided these pins are programmed to inputs by setting
the appropriate TRISC bits. Pull-up resistors must be
provided externally to the SCL and SDA pins for proper
operation of the I2C module.
Additional information on SSP I2C operation can be
found in the PICmicro Mid-Range MCU Family Ref-
erence Manual (DS33023A).
9.3.1 SLAVE MODE
In Slave mode, the SCL and SDA pins must be config-
ured as inputs (TRISC<4:3> set). The SSP module will
override the input state with the output data when
required (slave-transmitter).
When an address is matched, or the data transfer after
an address match is received, the hardware automati-
cally will generate the Acknowledge (ACK) pulse, and
then load the SSPBUF register with the received value
currently in the SSPSR register.
There are certain conditions that will cause the SSP
module not to give this ACK pulse. They include (either
or both):
a) The buffer full bit BF (SSPSTAT<0>) was set
before the transfer was received.
b) The overflow bit SSPOV (SSPCON<6>) was set
before the transfer was received.
In this case, the SSPSR register value is not loaded
into the SSPBUF, but bit SSPIF (PIR1<3>) is set.
Table 9-2 shows what happens when a data transfer
byte is received, given the status of bits BF and
SSPOV. The shaded cells show the condition where
user software did not properly clear the overflow condi-
tion. Flag bit BF is cleared by reading the SSPBUF reg-
ister, while bit SSPOV is cleared through software.
The SCL clock input must have a minimum high and
low for proper operation. The high and low times of the
I2C specification, as well as the requirements of the
SSP module, are shown in timing parameter #100 and
parameter #101.
Read Write
SSPSR reg
Match Detect
SSPADD reg
START and
STOP bit Detect
SSPBUF reg
Internal
Data Bus
Addr Match
Set, RESET
S, P bits
(SSPSTAT reg)
RC3/SCK/SCL
RC4/
Shift
Clock
MSb
SDI/ LSb
SDA
PIC16F7X
DS30325B-page 66 2002 Microchip Technology Inc.
9.3.1.1 Addressing
Once the SSP module has been enabled, it waits for a
START condition to occur. Following the START condi-
tion, the 8-bits are shifted into the SSPSR register. All
incoming bits are sampled with the rising edge of the
clock (SCL) line. The value of register SSPSR<7:1> is
compared to the value of the SSPADD register. The
address is compared on the falling edge of the eighth
clock (SCL) pulse. If the addresses match, and the BF
and SSPOV bits are clear, the following events occur:
a) The SSPSR register value is loaded into the
SSPBUF register.
b) The buffer full bit, BF is set.
c) An ACK pulse is generated.
d) SSP interrupt flag bit, SSPIF (PIR1<3>) is set
(interrupt is generated if enabled) - on the falling
edge of the ninth SCL pulse.
In 10-bit Address mode, two address bytes need to be
received by the slave (Figure 9-7). The five Most Sig-
nificant bits (MSbs) of the first address byte specify if
this is a 10-bit address. Bit R/W (SSPSTAT<2>) must
specify a write so the slave device will receive the sec-
ond address byte. For a 10-bit address, the first byte
would equal 1111 0 A9 A8 0, where A9 and A8 are
the two MSbs of the address.
The sequence of events for 10-bit address is as fol-
lows, with steps 7 - 9 for slave-transmitter:
1. Receive first (high) byte of address (bits SSPIF,
BF, and bit UA (SSPSTAT<1>) are set).
2. Update the SSPADD register with second (low)
byte of address (clears bit UA and releases the
SCL line).
3. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
4. Receive second (low) byte of address (bits
SSPIF, BF, and UA are set).
5. Update the SSPADD register with the first (high)
byte of address, if match releases SCL line, this
will clear bit UA.
6. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
7. Receive Repeated START condition.
8. Receive first (high) byte of address (bits SSPIF
and BF are set).
9. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
TABLE 9-2: DATA TRANSFER RECEIVED BYTE ACTIONS
9.3.1.2 Reception
When the R/W bit of the address byte is clear and an
address match occurs, the R/W bit of the SSPSTAT
register is cleared. The received address is loaded into
the SSPBUF register.
When the address byte overflow condition exists, then
no Acknowledge (ACK) pulse is given. An overflow
condition is defined as either bit BF (SSPSTAT<0>) is
set, or bit SSPOV (SSPCON<6>) is set. This is an error
condition due to the users firmware.
An SSP interrupt is generated for each data transfer
byte. Flag bit SSPIF (PIR1<3>) must be cleared in soft-
ware. The SSPSTAT register is used to determine the
status of the byte.
Status Bits as Data
Transfer is Received SSPSR SSPBUF Generate ACK
Pulse
Set bit SSPIF
(SSP Interrupt occurs
if enabled)
BF SSPOV
00 Yes Yes Yes
10 No No Yes
11 No No Yes
0 1 No No Yes
Note: Shaded cells show the conditions where the user software did not properly clear the overflow condition.
W wwwwww Wm; %
2002 Microchip Technology Inc. DS30325B-page 67
PIC16F7X
FIGURE 9-6: I2C WAVEFORMS FOR RECEPTION (7-BIT ADDRESS)
9.3.1.3 Transmission
When the R/W bit of the incoming address byte is set
and an address match occurs, the R/W bit of the
SSPSTAT register is set. The received address is
loaded into the SSPBUF register. The ACK pulse will
be sent on the ninth bit, and pin RC3/SCK/SCL is held
low. The transmit data must be loaded into the
SSPBUF register, which also loads the SSPSR regis-
ter. Then, pin RC3/SCK/SCL should be enabled by set-
ting bit CKP (SSPCON<4>). The master must monitor
the SCL pin prior to asserting another clock pulse. The
slave devices may be holding off the master by stretch-
ing the clock. The eight data bits are shifted out on the
falling edge of the SCL input. This ensures that the
SDA signal is valid during the SCL high time (Figure 9-7).
An SSP interrupt is generated for each data transfer
byte. Flag bit SSPIF must be cleared in software, and
the SSPSTAT register is used to determine the status
of the byte. Flag bit SSPIF is set on the falling edge of
the ninth clock pulse.
As a slave-transmitter, the ACK pulse from the master-
receiver is latched on the rising edge of the ninth SCL
input pulse. If the SDA line was high (not ACK), then
the data transfer is complete. When the ACK is latched
by the slave, the slave logic is reset (resets SSPSTAT
register) and the slave then monitors for another occur-
rence of the START bit. If the SDA line was low (ACK),
the transmit data must be loaded into the SSPBUF reg-
ister, which also loads the SSPSR register. Then pin
RC3/SCK/SCL should be enabled by setting bit CKP.
FIGURE 9-7: I2C WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)
P
9
8
7
6
5
D0
D1
D2
D3D4
D5
D6D7
S
A7 A6 A5 A4 A3 A2 A1SDA
SCL 123456789123456789123
4
Bus Master
terminates
transfer
Bit SSPOV is set because the SSPBUF register is still full.
Cleared in software
SSPBUF register is read
ACK Receiving Data
Receiving Data
D0
D1
D2
D3D4
D5
D6D7
ACK
R/W=0
Receiving Address
SSPIF (PIR1<3>)
BF (SSPSTAT<0>)
SSPOV (SSPCON<6>)
ACK
ACK is not sent.
SDA
SCL
SSPIF (PIR1<3>)
BF (SSPSTAT<0>)
CKP (SSPCON<4>)
A7 A6 A5 A4 A3 A2 A1 ACK D7 D6 D5 D4 D3 D2 D1 D0
ACK
Transmitting DataR/W = 1Receiving Address
123456789 123456789 P
Cleared in software
SSPBUF is written in software From SSP Interrupt
Service Routine
Set bit after writing to SSPBUF
SData in
sampled SCL held low
while CPU
responds to SSPIF
(the SSPBUF must be written to
before the CKP bit can be set)
PIC16F7X
DS30325B-page 68 2002 Microchip Technology Inc.
9.3.2 MASTER MODE
Master mode of operation is supported in firmware
using interrupt generation on the detection of the
START and STOP conditions. The STOP (P) and
START (S) bits are cleared from a RESET or when the
SSP module is disabled. The STOP (P) and START (S)
bits will toggle based on the START and STOP condi-
tions. Control of the I2C bus may be taken when the P
bit is set, or the bus is IDLE and both the S and P bits
are clear.
In Master mode, the SCL and SDA lines are manipu-
lated by clearing the corresponding TRISC<4:3> bit(s).
The output level is always low, irrespective of the
value(s) in PORTC<4:3>. So when transmitting data, a
1 data bit must have the TRISC<4> bit set (input) and
a 0 data bit must have the TRISC<4> bit cleared (out-
put). The same scenario is true for the SCL line with the
TRISC<3> bit. Pull-up resistors must be provided
externally to the SCL and SDA pins for proper opera-
tion of the I2C module.
The following events will cause SSP Interrupt Flag bit,
SSPIF, to be set (SSP Interrupt will occur if enabled):
START condition
STOP condition
Data transfer byte transmitted/received
Master mode of operation can be done with either the
Slave mode IDLE (SSPM3:SSPM0 = 1011), or with the
Slave active. When both Master and Slave modes are
enabled, the software needs to differentiate the
source(s) of the interrupt.
9.3.3 MULTI-MASTER MODE
In Multi-Master mode, the interrupt generation on the
detection of the START and STOP conditions, allows
the determination of when the bus is free. The STOP
(P) and START (S) bits are cleared from a RESET or
when the SSP module is disabled. The STOP (P) and
START (S) bits will toggle based on the START and
STOP conditions. Control of the I2C bus may be taken
when bit P (SSPSTAT<4>) is set, or the bus is IDLE
and both the S and P bits clear. When the bus is busy,
enabling the SSP Interrupt will generate the interrupt
when the STOP condition occurs.
In Multi-Master operation, the SDA line must be moni-
tored to see if the signal level is the expected output
level. This check only needs to be done when a high
level is output. If a high level is expected and a low level
is present, the device needs to release the SDA and
SCL lines (set TRISC<4:3>). There are two stages
where this arbitration can be lost, these are:
Address Transfer
Data Transfer
When the slave logic is enabled, the slave continues to
receive. If arbitration was lost during the address trans-
fer stage, communication to the device may be in
progress. If addressed, an ACK pulse will be gener-
ated. If arbitration was lost during the data transfer
stage, the device will need to retransfer the data at a
later time.
TABLE 9-3: REGISTERS ASSOCIATED WITH I2C OPERATION
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
0Bh, 8Bh,
10Bh,18Bh
INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
8Ch PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
93h SSPADD Synchronous Serial Port (I2C mode) Address Register 0000 0000 0000 0000
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
94h SSPSTAT SMP(2) CKE(2) D/A PSR/WUA BF 0000 0000 0000 0000
87h TRISC PORTC Data Direction Register 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented locations read as 0. Shaded cells are not used by SSP module in I2C mode.
Note 1: PSPIF and PSPIE are reserved on the PIC16F73/76; always maintain these bits clear.
2: Maintain these bits clear in I2C mode.
Asynchronous mode. Synchronous mode. Asynchronous mode. Synchronous mode.
2002 Microchip Technology Inc. DS30325B-page 69
PIC16F7X
10.0 UNIVERSAL SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (USART)
The Universal Synchronous Asynchronous Receiver
Transmitter (USART) module is one of the two serial
I/O modules. (USART is also known as a Serial Com-
munications Interface or SCI.) The USART can be con-
figured as a full duplex asynchronous system that can
communicate with peripheral devices, such as CRT ter-
minals and personal computers, or it can be configured
as a half duplex synchronous system that can commu-
nicate with peripheral devices, such as A/D or D/A inte-
grated circuits, serial EEPROMs, etc.
The USART can be configured in the following modes:
Asynchronous (full duplex)
Synchronous - Master (half duplex)
Synchronous - Slave (half duplex)
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 Asynchro-
nous Receiver Transmitter.
REGISTER 10-1: 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:
Dont 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 reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
Asynchronous mode. Synchronous mode - Masler. Synchronous mode - S‘ave. Asynchronous mode. Synchronous mode.
PIC16F7X
DS30325B-page 70 2002 Microchip Technology Inc.
REGISTER 10-2: RCSTA: RECEIVE STATUS AND CONTROL REGISTER (ADDRESS 18h)
R/W-0 R/W-0 R/W-0 R/W-0 U-0 R-0 R-0 R-x
SPEN RX9 SREN CREN 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:
Dont care
Synchronous mode - Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode - Slave:
Dont 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 Unimplemented: Read as '0'
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 (parity to be calculated by firmware)
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as 0
- n = Value at POR reset 1 = Bit is set 0 = Bit is cleared x = Bit is unknown
2002 Microchip Technology Inc. DS30325B-page 71
PIC16F7X
10.1 USART Baud Rate Generator
(BRG)
The BRG supports both the Asynchronous and Syn-
chronous 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 10-1 shows the formula for computation of the
baud rate for different USART modes which only apply
in Master mode (internal clock).
Given the desired baud rate and FOSC, the nearest
integer value for the SPBRG register can be calculated
using the formula in Table 10-1. From this, the error in
baud rate can be determined.
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.
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 output-
ting the new baud rate.
10.1.1 SAMPLING
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.
TABLE 10-1: BAUD RATE FORMULA
TABLE 10-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
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
X = value in SPBRG (0 to 255)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR,
BOR
Value on
all other
RESETS
98h TXSTA CSRC TX9 TXEN SYNC BRGH TRMT TX9D 0000 -010 0000 -010
18h RCSTA SPEN RX9 SREN CREN FERR OERR RX9D 0000 -00x 0000 -00x
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used by the BRG.
PIC16F7X
DS30325B-page 72 2002 Microchip Technology Inc.
TABLE 10-3: BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 0)
BAUD
RATE
FOSC = 20 MHz FOSC = 16 MHz FOSC = 10 MHz
BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL)
1200 1,221 1.73% 255 1,202 0.16% 207 1,202 0.16% 129
2400 2,404 0.16% 129 2,404 0.16% 103 2,404 0.16% 64
9600 9,470 -1.36% 32 9,615 0.16% 25 9,766 1.73% 15
19,200 19,531 1.73% 15 19,231 0.16% 12 19,531 1.73% 7
38,400 39,063 1.73% 7 35,714 -6.99% 6 39,063 1.73% 3
57,600 62,500 8.51% 4 62,500 8.51% 3 52,083 -9.58% 2
76,800 78,125 1.73% 3 83,333 8.51% 2 78,125 1.73% 1
96,000 104,167 8.51% 2 83,333 -13.19% 2 78,125 -18.62% 1
115,200 104,167 -9.58% 2 125,000 8.51% 1 78,125 -32.18% 1
250,000 312,500 25.00% 0 250,000 0.00% 0 156,250 -37.50% 0
BAUD
RATE
FOSC = 4 MHz FOSC = 3.6864 MHz FOSC = 3.579545 MHz
BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL)
300 300 0.16% 207 300 0.00% 191 301 0.23% 185
1200 1,202 0.16% 51 1,200 0.00% 47 1,190 -0.83% 46
2400 2,404 0.16% 25 2,400 0.00% 23 2,432 1.32% 22
9600 8,929 -6.99% 6 9,600 0.00% 5 9,322 -2.90% 5
19,200 20,833 8.51% 2 19,200 0.00% 2 18,643 -2.90% 2
38,400 31,250 -18.62% 1 28,800 -25.00% 1 27,965 -27.17% 1
57,600 62,500 8.51% 0 57,600 0.00% 0 55,930 -2.90% 0
76,800 62,500 -18.62% 0 —— — —
TABLE 10-4: BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 1)
BAUD
RATE
FOSC = 20 MHz FOSC = 16 MHz FOSC = 10 MHz
BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL)
2400 —— —— —2,441 1.73% 255
9600 9,615 0.16% 129 9,615 0.16% 103 9,615 0.16% 64
19,200 19,231 0.16% 64 19,231 0.16% 51 18,939 -1.36% 32
38,400 37,879 -1.36% 32 38,462 0.16% 25 39,063 1.73% 15
57,600 56,818 -1.36% 21 58,824 2.12% 16 56,818 -1.36% 10
76,800 78,125 1.73% 15 76,923 0.16% 12 78,125 1.73% 7
96,000 96,154 0.16% 12 100,000 4.17% 9 89,286 -6.99% 6
115,200 113,636 -1.36% 10 111,111 -3.55% 8 125,000 8.51% 4
250,000 250,000 0.00% 4 250,000 0.00% 3 208,333 -16.67% 2
300,000 312,500 4.17% 3 333,333 11.11% 2 312,500 4.17% 1
BAUD
RATE
(K)
FOSC = 4 MHz FOSC = 3.6864 MHz FOSC = 3.579545 MHz
BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL) BAUD %
ERROR
SPBRG
VALUE
(DECIMAL)
1200 1,202 0.16% 207 1,200 0.00% 191 1,203 0.23% 185
2400 2,404 0.16% 103 2,400 0.00% 95 2,406 0.23% 92
9600 9,615 0.16% 25 9,600 0.00% 23 9,727 1.32% 22
19,200 19,231 0.16% 12 19,200 0.00% 11 18,643 -2.90% 11
38,400 35,714 -6.99% 6 38,400 0.00% 5 37,287 -2.90% 5
57,600 62,500 8.51% 3 57,600 0.00% 3 55,930 -2.90% 3
76,800 83,333 8.51% 2 76,800 0.00% 2 74,574 -2.90% 2
96,000 83,333 -13.19% 2 115,200 20.00% 1 111,861 16.52% 1
115,200 125,000 8.51% 1 115,200 0.00% 1 111,861 -2.90% 1
250,000 250,000 0.00% 0 230,400 -7.84% 0 223,722 -10.51% 0
2002 Microchip Technology Inc. DS30325B-page 73
PIC16F7X
10.2 USART Asynchronous Mode
In this mode, the USART uses standard non-return-to-
zero (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 gener-
ator can be used to derive standard baud rate frequen-
cies from the oscillator. The USART transmits and
receives the LSb first. The USART’s transmitter and
receiver are functionally independent, but use the
same data format and baud rate. The baud rate gener-
ator 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). Asynchro-
nous mode is stopped during SLEEP.
Asynchronous mode is selected by clearing bit SYNC
(TXSTA<4>).
The USART Asynchronous module consists of the fol-
lowing important elements:
Baud Rate Generator
Sampling Circuit
Asynchronous Transmitter
Asynchronous Receiver
10.2.1 USART ASYNCHRONOUS
TRANSMITTER
The USART transmitter block diagram is shown in
Figure 10-1. 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 by firmware. 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, the
TXREG register is empty. One instruction cycle later,
flag bit TXIF (PIR1<4>) and flag bit TRMT (TXSTA<1>)
are set. The TXIF 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 reg-
ister. Status bit TRMT is a read only bit, which is set one
instruction cycle after the TSR register becomes empty,
and is cleared one instruction cycle after the TSR regis-
ter is loaded. 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.
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 10-2). 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 10-3). Clearing enable
bit TXEN during a transmission will cause the transmis-
sion to be aborted and will reset the transmitter. As a
result, the RC6/TX/CK pin will revert to hi-impedance.
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 writ-
ten 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