PIC16F685/687/689/690 Data Sheet 20-Pin Flash-Based, 8-Bit CMOS Microcontrollers with

PIC16F685/687/689/690 Data Sheet 20-Pin Flash-Based, 8-Bit CMOS Microcontrollers with
PIC16F685/687/689/690
Data Sheet
20-Pin Flash-Based, 8-Bit
CMOS Microcontrollers with
nanoWatt Technology
© 2005 Microchip Technology Inc.
Preliminary
DS41262A
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED,
WRITTEN OR ORAL, STATUTORY OR OTHERWISE,
RELATED TO THE INFORMATION, INCLUDING BUT NOT
LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE,
MERCHANTABILITY OR FITNESS FOR PURPOSE.
Microchip disclaims all liability arising from this information and
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life support systems is not authorized except with express
written approval by Microchip. No licenses are conveyed,
implicitly or otherwise, under any Microchip intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE, PowerSmart, rfPIC, and SmartShunt are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.
AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB,
PICMASTER, SEEVAL, SmartSensor and The Embedded
Control Solutions Company are registered trademarks of
Microchip Technology Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, dsPICDEM,
dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR,
FanSense, FlexROM, fuzzyLAB, In-Circuit Serial
Programming, ICSP, ICEPIC, MPASM, MPLIB, MPLINK,
MPSIM, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail,
PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB,
rfPICDEM, Select Mode, Smart Serial, SmartTel, Total
Endurance and WiperLock are trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
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.
© 2005, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 quality system certification for
its worldwide headquarters, design and wafer fabrication facilities in
Chandler and Tempe, Arizona and Mountain View, California in
October 2003. The Company’s quality system processes and
procedures are for its PICmicro® 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
DS41262A-page ii
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
20-Pin Flash-Based, 8-Bit CMOS Microcontrollers with
nanoWatt Technology
High-Performance RISC CPU:
Low-Power Features:
• Only 35 instructions to learn:
- All single-cycle instructions except branches
• Operating speed:
- DC – 20 MHz oscillator/clock input
- DC – 200 ns instruction cycle
• Interrupt capability
• 8-level deep hardware stack
• Direct, Indirect and Relative Addressing modes
• Standby Current:
- 1 nA @ 2.0V, typical
• Operating Current:
- 20 μA @ 32 kHz, 2.0V, typical
- <1 mA @ 4 MHz, 5.5V, typical
• Watchdog Timer Current:
- <1 μA @ 2.0V, typical
Peripheral Features:
Special Microcontroller Features:
• Precision Internal Oscillator:
- Factory calibrated to ± 1%
- Software selectable frequency range of
8 MHz to 32 kHz
- Software tunable
- Two-Speed Start-up mode
- Crystal fail detect for critical applications
- Clock mode switching during operation for
power savings
• Power-saving Sleep mode
• Wide operating voltage range (2.0V-5.5V)
• Industrial and Extended Temperature range
• Power-on Reset (POR)
• Power-up Timer (PWRTE) and Oscillator Start-up
Timer (OST)
• Brown-out Reset (BOR) with software control
option
• Enhanced low-current Watchdog Timer (WDT)
with on-chip oscillator (software selectable
nominal 268 seconds with full prescaler) with
software enable
• Multiplexed Master Clear/Input pin
• Programmable code protection
• High Endurance Flash/EEPROM cell:
- 100,000 write Flash endurance
- 1,000,000 write EEPROM endurance
- Flash/Data EEPROM retention: > 40 years
• Enhanced USART Module:
- Supports RS-485, RS-232, and LIN 2.0
- Auto-Baud Detect
- Auto-wake-up on Start bit
© 2005 Microchip Technology Inc.
• 17 I/O pins and 1 input only pin:
- High current source/sink for direct LED drive
- Interrupt-on-pin change
- Individually programmable weak pull-ups
- Ultra Low-Power Wake-up (ULPWU)
• Analog comparator module with:
- Two analog comparators
- Programmable on-chip voltage reference
(CVREF) module (% of VDD)
- Comparator inputs and outputs externally
accessible
- SR Latch mode
- Timer 1 Gate Sync Latch
• A/D Converter:
- 10-bit resolution and 12 channels
• Timer0: 8-bit timer/counter with 8-bit
programmable prescaler
• Enhanced Timer1:
- 16-bit timer/counter with prescaler
- External Gate Input mode
- Option to use OSC1 and OSC2 in LP mode
as Timer1 oscillator if INTOSC mode
selected
• Timer2: 8-bit timer/counter with 8-bit period
register, prescaler and postscaler
• Enhanced Capture, Compare, PWM+ module:
- 16-bit Capture, max resolution 12.5 ns
- Compare, max resolution 200 ns
- 10-bit PWM with 1, 2 or 4 output channels,
programmable “dead time”, max frequency
20 kHz
- PWM output steering control
• Synchronous Serial Port (SSP):
- SPI™ mode (Master and Slave)
• I2C™ (Master/Slave modes):
- I2C™ address mask
• In-Circuit Serial ProgrammingTM (ICSPTM) via two
pins
Preliminary
DS41262A-page 1
PIC16F685/687/689/690
Program
Memory
Data Memory
Device
I/O
10-bit A/D
Comparators
(ch)
Timers
8/16-bit
SSP
ECCP+ EUSART
Flash
(words)
SRAM
(bytes)
EEPROM
(bytes)
PIC16F685
PIC16F687
PIC16F689
4096
2048
4096
256
128
256
256
256
256
18
18
18
12
12
12
2
2
2
2/1
1/1
1/1
No
Yes
Yes
Yes
No
No
No
Yes
Yes
PIC16F690
4096
256
256
18
12
2
2/1
Yes
Yes
Yes
Pin Diagrams
VDD
RA5/T1CKI/OSC1/CLKIN
RA4/AN3/T1G/OSC2/CLKOUT
RA3/MCLR/VPP
RC5/CPP1
RC4/C2OUT
RC3/AN7
RC6/AN8/SS
RC7/AN9/SDO
RB7/TX/CK
1
2
3
4
5
6
7
8
9
10
VDD
RA5/T1CKI/OSC1/CLKIN
RA4/AN3/T1G/OSC2/CLKOUT
RA3/MCLR/VPP
RC5/CCP1/P1A
RC4/C2OUT/P1B
RC3/AN7/P1C
RC6/AN8/SS
RC7/AN9/SDO
RB7/TX/CK
1
2
3
4
5
6
7
8
9
10
DS41262A-page 2
20
19
18
17
16
15
14
13
12
11
VSS
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RC0/AN4/C2IN+
RC1/AN5/C12INRC2/AN6/P1D
RB4/AN10
RB5/AN11
RB6
20
19
18
17
16
15
14
13
12
11
VSS
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RC0/AN4/C2IN+
RC1/AN5/C12INRC2/AN6
RB4/AN10/SDI/SDA
RB5/AN11/RX/DT
RB6/SCK/SCL
20
19
18
17
16
15
14
13
12
11
VSS
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RC0/AN4/C2IN+
RC1/AN5/C12INRC2/AN6/P1D
RB4/AN10/SDI/SDA
RB5/AN11/RX/DT
RB6/SCK/SCL
PIC16F685
1
2
3
4
5
6
7
8
9
10
PIC16F687/689
VDD
RA5/T1CKI/OSC1/CLKIN
RA4/AN3/T1G/OSC2/CLKOUT
RA3/MCLR/VPP
RC5/CCP1/P1A
RC4/C2OUT/P1B
RC3/AN7/P1C
RC6/AN8
RC7/AN9
RB7
PIC16F690
20-pin PDIP, SOIC, SSOP
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
Pin Diagrams (Continued)
RA3/MCLR/VPP
1
RC5/CCP1/P1A(1)
2
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
VDD
VSS
RA0/AN0/C1IN+/ICSPDAT/ULPWU
20
19
18
17
16
20-pin QFN
PIC16F685/687/
689/690
14
RA2/AN2/T0CKI/INT/C1OUT
13
RC0/AN4/C2IN+
RC2/AN6/P1D(1)
RB4/AN10/SDI/SDA(2)
RB7/TX/CK
(2)
6
RC7/AN9/SDO(2)
9
11
10
5
RB5/AN11/RX/DT(2)
RC1/AN5/C12IN-
7
12
8
4
RC6/AN8/SS(2)
RB6/SCK/SCL(2)
3
(1)
RC3/AN7/P1C
2:
RA1/AN1/C12IN-/VREF/ICSPCLK
(1)
RC4/C2OUT/P1B
Note 1:
15
P1A, P1B, P1C and P1D are available on PIC16F685/PIC16F690 only.
SS, SDO, SDA, RX and DT available on PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 3
PIC16F685/687/689/690
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 5
2.0 Memory Organization ................................................................................................................................................................. 15
3.0 Clock Sources ............................................................................................................................................................................ 35
4.0 I/O Ports ..................................................................................................................................................................................... 47
5.0 Timer0 Module ........................................................................................................................................................................... 69
6.0 Timer1 Module with Gate Control............................................................................................................................................... 73
7.0 Timer2 Module ........................................................................................................................................................................... 77
8.0 Comparator Module.................................................................................................................................................................... 79
9.0 Analog-to-Digital Converter (A/D) Module .................................................................................................................................. 93
10.0 Data EEPROM and Flash Program Memory Control ............................................................................................................... 105
11.0 Enhanced Capture/Compare/PWM+ (ECCP+) Module ........................................................................................................... 113
12.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 131
13.0 SSP Module Overview ............................................................................................................................................................. 155
14.0 Special Features of the CPU .................................................................................................................................................... 173
15.0 Instruction Set Summary .......................................................................................................................................................... 193
16.0 Development Support............................................................................................................................................................... 203
17.0 Electrical Specifications............................................................................................................................................................ 209
18.0 DC and AC Characteristics Graphs and Tables ....................................................................................................................... 237
19.0 Packaging Information.............................................................................................................................................................. 239
Appendix A: Data Sheet Revision History.......................................................................................................................................... 245
Appendix B: Migrating from other PICmicro® Devices ...................................................................................................................... 245
The Microchip Web Site ..................................................................................................................................................................... 253
Customer Change Notification Service .............................................................................................................................................. 253
Customer Support .............................................................................................................................................................................. 253
Reader Response .............................................................................................................................................................................. 254
Product Identification System............................................................................................................................................................. 255
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and
enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via Email at [email protected] or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of
silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
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• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
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DS41262A-page 4
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
1.0
DEVICE OVERVIEW
Block Diagrams and pinout descriptions of the devices
are as follows:
The PIC16F685/687/689/690 devices are covered by
this data sheet. They are available in 20-pin PDIP,
SOIC, TSSOP and QFN packages.
FIGURE 1-1:
• PIC16F685 (Figure 1-1, Table 1-1)
• PIC16F687/PIC16F689 (Figure 1-2, Table 1-2)
• PIC16F690 (Figure 1-3, Table 1-3)
PIC16F685 BLOCK DIAGRAM
INT
Configuration
13
8
Data Bus
PORTA
Program Counter
Flash
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
4k x 14
Program
RAM
256 bytes
File
Registers
8-Level Stack (13-bit)
Memory
Program 14
Bus
RAM Addr
9
PORTB
Addr MUX
Instruction Reg
7
Direct Addr
8
Indirect
Addr
RB4/AN10
RB5/AN11
RB6
RB7
FSR Reg
Status Reg
8
PORTC
3
Power-up
Timer
Instruction
Decode and
Control
Oscillator
Start-up Timer
OSC1/CLKI
OSC2/CLKO
ALU
Power-on
Reset
Timing
Generation
RC0/AN4/C2IN+
RC1/AN5/C12INRC2/AN6/P1D
RC3/AN7/P1C
RC4/C2OUT/P1B
RC5/CCP1/P1A
RC6/AN8
RC7/AN9
MUX
8
Watchdog
Timer
W Reg
Brown-out
Reset
Internal
Oscillator
Block
MCLR VDD
T0CKI
Timer0
VSS
T1G
CCP1/
P1A
T1CKI
Timer1
Timer2
P1B P1C P1D
ECCP+
AN8 AN9 AN10 AN11
Analog-To-Digital Converter
2
Analog Comparators
and Reference
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
© 2005 Microchip Technology Inc.
Preliminary
EEDAT
8
256 Bytes
Data
EEPROM
EEADR
DS41262A-page 5
PIC16F685/687/689/690
FIGURE 1-2:
PIC16F687/PIC16F689 BLOCK DIAGRAM
INT
Configuration
13
8
Data Bus
PORTA
Program Counter
Flash
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
2k(1)/4k x 14
Program
RAM
128(1)/256 bytes
File
Registers
8-Level Stack (13-bit)
Memory
Program 14
Bus
RAM Addr
9
PORTB
Addr MUX
Instruction Reg
7
Direct Addr
8
Indirect
Addr
RB4/AN10/SDI/SDA
RB5/AN11/RX/DT
RB6/SCK/SCL
RB7/TX/CK
FSR Reg
Status Reg
8
PORTC
3
Power-up
Timer
Instruction
Decode and
Control
Oscillator
Start-up Timer
OSC1/CLKI
OSC2/CLKO
ALU
Power-on
Reset
Timing
Generation
RC0/AN4/C2IN+
RC1/AN5/C12INRC2/AN6
RC3/AN7
RC4/C2OUT
RC5/CCP1
RC6/AN8/SS
RC7/AN9/SDO
MUX
8
Watchdog
Timer
W Reg
Brown-out
Reset
Internal
Oscillator
Block
MCLR VDD
T0CKI
Timer0
VSS
T1G
T1CKI
Timer1
TX/CK RX/DT
SDI/ SCK/
SDO SDA SCL SS
EUSART
Synchronous
Serial Port
AN8 AN9 AN10 AN11
Analog-To-Digital Converter
2
Analog Comparators
and Reference
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
EEDAT
8
256 Bytes
Data
EEPROM
EEADR
Note 1: PIC16F687 only.
DS41262A-page 6
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 1-3:
PIC16F690 BLOCK DIAGRAM
INT
Configuration
13
8
Data Bus
PORTA
Program Counter
Flash
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
4k x 14
Program
RAM
256 bytes
File
Registers
8-Level Stack (13-bit)
Memory
Program 14
Bus
RAM Addr
9
PORTB
Addr MUX
Instruction Reg
Direct Addr
7
8
Indirect
Addr
RB4/AN10/SDI/SDA
RB5/AN11/RX/DT
RB6/SCK/SCL
RB7/TX/CK
FSR Reg
Status Reg
8
PORTC
3
Power-up
Timer
Instruction
Decode and
Control
Oscillator
Start-up Timer
OSC1/CLKI
OSC2/CLKO
Power-on
Reset
Timing
Generation
Watchdog
Timer
RC0/AN4/C2IN+
RC1/AN5/C12INRC2/AN6/P1D
RC3/AN7/P1C
RC4/C2OUT/P1B
RC5/CCP1/P1A
RC6/AN8/SS
RC7/AN9/SDO
MUX
ALU
8
W Reg
Brown-out
Reset
Internal
Oscillator
Block
MCLR VDD
T0CKI
Timer0
T1G
VSS
TX/CK RX/DT
T1CKI
Timer1
Timer2
CCP1/
P1A
P1B P1C P1D
ECCP+
EUSART
SDI/ SCK/
SDO SDA SCL SS
Synchronous
Serial Port
AN8 AN9 AN10 AN11
Analog-To-Digital Converter
2
Analog Comparators
and Reference
VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT
© 2005 Microchip Technology Inc.
Preliminary
EEDAT
8
256 Bytes
Data
EEPROM
EEADR
DS41262A-page 7
PIC16F685/687/689/690
TABLE 1-1:
PINOUT DESCRIPTION – PIC16F685
Name
RA0/AN0/C1IN+/ICSPDAT/
ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
RB4/AN10
RB5/AN11
Function
Input
Type
Output
Type
RA0
TTL
—
Description
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
AN0
AN
—
A/D Channel 0 input.
C1IN+
AN
—
Comparator 1 positive input.
ICSPDAT
TTL
CMOS
ULPWU
AN
—
RA1
TTL
CMOS
ICSP™ Data I/O.
Ultra Low-Power Wake-up input.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
AN1
AN
—
A/D Channel 1 input.
C12IN-
AN
—
Comparator 1 or 2 negative input.
VREF
AN
—
External Voltage Reference for A/D.
ICSPCLK
ST
—
ICSP™ clock.
RA2
ST
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
AN2
AN
—
A/D Channel 2 input.
T0CKI
ST
—
Timer0 clock input.
External interrupt pin.
INT
ST
—
C1OUT
—
CMOS
RA3
TTL
—
General purpose input. Individually controlled interrupt-onchange.
MCLR
ST
—
Master Clear with internal pull-up.
Programming voltage.
Comparator 1 output.
VPP
HV
—
RA4
TTL
CMOS
AN3
AN
—
A/D Channel 3 input.
T1G
ST
—
Timer1 gate input.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
OSC2
—
XTAL
Crystal/Resonator.
CLKOUT
—
CMOS
FOSC/4 output.
RA5
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
T1CKI
ST
—
Timer1 clock input.
OSC1
XTAL
—
Crystal/Resonator.
CLKIN
ST
—
External clock input/RC oscillator connection.
RB4
TTL
CMOS
AN10
AN
—
RB5
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
A/D Channel 10 input.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
AN11
AN
—
RB6
RB6
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
RB7
RB7
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
RC0/AN4/C2IN+
RC0
ST
CMOS
General purpose I/O.
AN4
AN
—
A/D Channel 4 input.
C2IN+
AN
—
Comparator 2 positive input.
Legend:
AN = Analog input or output
TTL = TTL compatible input
HV = High Voltage
DS41262A-page 8
A/D Channel 11 input.
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
XTAL = Crystal
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 1-1:
PINOUT DESCRIPTION – PIC16F685 (CONTINUED)
Name
RC1/AN5/C12IN-
RC2/AN6/P1D
RC3/AN7/P1C
RC4/C2OUT/P1B
Function
Input
Type
Output
Type
RC1
ST
CMOS
Description
General purpose I/O.
AN5
AN
—
A/D Channel 5 input.
C12IN-
AN
—
Comparator 1 or 2 negative input.
RC2
ST
CMOS
General purpose I/O.
AN6
AN
—
A/D Channel 6 input.
P1D
—
CMOS
PWM output.
RC3
ST
CMOS
General purpose I/O.
AN7
AN
—
P1C
—
CMOS
PWM output.
A/D Channel 7 input.
RC4
ST
CMOS
General purpose I/O.
C2OUT
—
CMOS
Comparator 2 output.
P1B
—
CMOS
PWM output.
RC5
ST
CMOS
General purpose I/O.
CCP1
ST
CMOS
Capture/Compare input.
P1A
ST
CMOS
PWM output.
RC6
ST
CMOS
General purpose I/O.
AN8
AN
—
A/D Channel 8 input.
RC7
ST
CMOS
General purpose I/O.
AN9
AN
—
A/D Channel 9 input.
VSS
VSS
Power
—
Ground reference.
VDD
VDD
Power
—
Positive supply.
RC5/CCP1/P1A
RC6/AN8
RC7/AN9
Legend:
AN = Analog input or output
TTL = TTL compatible input
HV = High Voltage
© 2005 Microchip Technology Inc.
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
XTAL = Crystal
Preliminary
DS41262A-page 9
PIC16F685/687/689/690
TABLE 1-2:
PINOUT DESCRIPTION – PIC16F687/PIC16F689
Name
RA0/AN0/C1IN+/ICSPDAT/
ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
RB4/AN10/SDI/SDA
RB5/AN11/RX/DT
Function
Input
Type
Output
Type
RA0
TTL
—
AN0
AN
—
A/D Channel 0 input.
AN
—
Comparator 1 positive input.
ICSPDAT
TTL
CMOS
ULPWU
AN
—
RA1
TTL
CMOS
ICSP Data I/O.
Ultra Low-Power Wake-up input.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
AN1
AN
—
A/D Channel 1 input.
C12IN-
AN
—
Comparator 1 or 2 negative input.
VREF
AN
—
External Voltage Reference for A/D.
ICSPCLK
ST
—
ICSP™ clock.
RA2
ST
CMOS
AN2
AN
—
A/D Channel 2 input.
T0CKI
ST
—
Timer0 clock input.
INT
ST
—
C1OUT
—
CMOS
RA3
TTL
—
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
External Interrupt.
Comparator 1 output.
General purpose input. Individually controlled interrupt-onchange.
MCLR
ST
—
Master Clear with internal pull-up.
VPP
HV
—
Programming voltage.
RA4
TTL
CMOS
AN3
AN
—
T1G
ST
—
Timer1 gate input.
OSC2
—
XTAL
Crystal/Resonator.
CLKOUT
—
CMOS
FOSC/4 output.
RA5
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
T1CKI
ST
—
Timer1 clock input.
OSC1
XTAL
—
Crystal/Resonator.
External clock input/RC oscillator connection.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
A/D Channel 3 input.
CLKIN
ST
—
RB4
TTL
CMOS
AN10
AN
—
A/D Channel 10 input.
SDI
ST
—
SPI™ data input.
SDA
ST
OD
I2C data input/output.
RB5
TTL
CMOS
AN11
AN
—
A/D Channel 11 input.
RX
ST
—
EUSART asynchronous input.
ST
CMOS
AN = Analog input or output
TTL = TTL compatible input
HV = High Voltage
DS41262A-page 10
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
C1IN+
DT
Legend:
Description
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
EUSART synchronous data.
CMOS = CMOS compatible input or output
OD = Open Drain
ST
= Schmitt Trigger input with CMOS levels
XTAL = Crystal
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 1-2:
PINOUT DESCRIPTION – PIC16F687/PIC16F689 (CONTINUED)
Name
RB6/SCK/SCL
RB7/TX/CK
RC0/AN4/C2IN+
Function
Input
Type
Output
Type
RB6
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
SCK
ST
CMOS
SPI™ clock.
SCL
ST
OD
I2C™ clock.
RB7
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
TX
—
CMOS
EUSART asynchronous output.
Description
CK
ST
CMOS
EUSART synchronous clock.
RC0
ST
CMOS
General purpose I/O.
AN4
AN
—
A/D Channel 4 input.
C2IN+
AN
—
Comparator 2 positive input.
RC1
ST
CMOS
AN5
AN
—
A/D Channel 5 input.
C12IN-
AN
—
Comparator 1 or 2 negative input.
RC2/AN6
RC2
ST
CMOS
AN6
AN
—
A/D Channel 6 input.
RC3/AN7
RC3
ST
CMOS
General purpose I/O.
AN7
AN
—
A/D Channel 7 input.
RC4/C2OUT
RC4
ST
CMOS
General purpose I/O.
RC1/AN5/C12IN-
RC5/CCP1
RC6/AN8/SS
RC7/AN9/SDO
VSS
Legend:
—
CMOS
Comparator 2 output.
RC5
ST
CMOS
General purpose I/O.
CCP1
ST
CMOS
Capture/Compare input.
RC6
ST
CMOS
General purpose I/O.
AN8
AN
—
A/D Channel 8 input.
SS
ST
—
Slave Select input.
RC7
ST
CMOS
General purpose I/O.
AN9
AN
—
A/D Channel 9 input.
SDO
—
CMOS
VSS
Power
—
Ground reference.
Power
—
Positive supply.
AN = Analog input or output
TTL = TTL compatible input
HV = High Voltage
© 2005 Microchip Technology Inc.
General purpose I/O.
C2OUT
VDD
VDD
General purpose I/O.
SPI data output.
CMOS = CMOS compatible input or output
OD = Open Drain
ST
= Schmitt Trigger input with CMOS levels
XTAL = Crystal
Preliminary
DS41262A-page 11
PIC16F685/687/689/690
TABLE 1-3:
PINOUT DESCRIPTION – PIC16F690
Name
RA0/AN0/C1IN+/ICSPDAT/
ULPWU
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
RA5/T1CKI/OSC1/CLKIN
RB4/AN10/SDI/SDA
RB5/AN11/RX/DT
Function
Input
Type
Output
Type
RA0
TTL
—
AN0
AN
—
A/D Channel 0 input.
AN
—
Comparator 1 positive input.
ICSPDAT
TTL
CMOS
ULPWU
AN
—
RA1
TTL
CMOS
ICSP Data I/O.
Ultra Low-Power Wake-up input.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
AN1
AN
—
A/D Channel 1 input.
C12IN-
AN
—
Comparator 1 or 2 negative input.
VREF
AN
—
External Voltage Reference for A/D.
ICSPCLK
ST
—
ICSP™ clock.
RA2
ST
CMOS
AN2
AN
—
A/D Channel 2 input.
T0CKI
ST
—
Timer0 clock input.
INT
ST
—
C1OUT
—
CMOS
RA3
TTL
—
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
External Interrupt.
Comparator 1 output.
General purpose input. Individually controlled interrupt-onchange.
MCLR
ST
—
Master Clear with internal pull-up.
VPP
HV
—
Programming voltage.
RA4
TTL
CMOS
AN3
AN
—
T1G
ST
—
Timer1 gate input.
OSC2
—
XTAL
Crystal/Resonator.
CLKOUT
—
CMOS
FOSC/4 output.
RA5
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
T1CKI
ST
—
Timer1 clock input.
OSC1
XTAL
—
Crystal/Resonator.
External clock input/RC oscillator connection.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
A/D Channel 3 input.
CLKIN
ST
—
RB4
TTL
CMOS
AN10
AN
—
A/D Channel 10 input.
SDI
ST
—
SPI data input.
SDA
ST
OD
I2C data input/output.
RB5
TTL
CMOS
AN11
AN
—
A/D Channel 11 input.
RX
ST
—
EUSART asynchronous input.
ST
CMOS
AN = Analog input or output
TTL = TTL compatible input
HV = High Voltage
DS41262A-page 12
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
C1IN+
DT
Legend:
Description
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
EUSART synchronous data.
CMOS = CMOS compatible input or output
OD = Open Drain
ST
= Schmitt Trigger input with CMOS levels
XTAL = Crystal
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 1-3:
PINOUT DESCRIPTION – PIC16F690 (CONTINUED)
Name
RB6/SCK/SCL
RB7/TX/CK
RC0/AN4/C2IN+
RC1/AN5/C12IN-
RC2/AN6/P1D
RC3/AN7/P1C
RC4/C2OUT/P1B
RC5/CCP1/P1A
RC6/AN8/SS
RC7/AN9/SDO
VSS
Input
Type
Output
Type
RB6
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
SCK
ST
CMOS
SPI™ clock.
SCL
ST
OD
I2C™ clock.
RB7
TTL
CMOS
General purpose I/O. Individually controlled interrupt-onchange. Individually enabled pull-up.
TX
—
CMOS
EUSART asynchronous output.
CK
ST
CMOS
EUSART synchronous clock.
ST
CMOS
General purpose I/O.
AN4
AN
—
A/D Channel 4 input.
C2IN+
AN
—
Comparator 2 positive input.
RC1
ST
CMOS
AN5
AN
—
A/D Channel 5 input.
C12IN-
AN
—
Comparator 1 or 2 negative input.
RC2
ST
CMOS
AN6
AN
—
P1D
—
CMOS
PWM output.
RC3
ST
CMOS
General purpose I/O.
AN7
AN
—
A/D Channel 7 input.
General purpose I/O.
General purpose I/O.
A/D Channel 6 input.
P1C
—
CMOS
PWM output.
RC4
ST
CMOS
General purpose I/O.
C2OUT
—
CMOS
Comparator 2 output.
P1B
—
CMOS
PWM output.
RC5
ST
CMOS
General purpose I/O.
CCP1
ST
CMOS
Capture/Compare input.
P1A
ST
CMOS
PWM output.
RC6
ST
CMOS
General purpose I/O.
AN8
AN
—
A/D Channel 8 input.
SS
ST
—
Slave Select input.
RC7
ST
CMOS
General purpose I/O.
AN9
AN
—
A/D Channel 9 input.
SDO
—
CMOS
VSS
Power
—
Ground reference.
Power
—
Positive supply.
AN = Analog input or output
TTL = TTL compatible input
HV = High Voltage
© 2005 Microchip Technology Inc.
Description
RC0
VDD
VDD
Legend:
Function
SPI data output.
CMOS = CMOS compatible input or output
OD = Open Drain
ST
= Schmitt Trigger input with CMOS levels
XTAL = Crystal
Preliminary
DS41262A-page 13
PIC16F685/687/689/690
NOTES:
DS41262A-page 14
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
2.0
MEMORY ORGANIZATION
2.1
Program Memory Organization
FIGURE 2-2:
The PIC16F685/687/689/690 has a 13-bit program
counter capable of addressing an 8k x 14 program
memory space. Only the first 2k x 14 (0000h-07FFh) for
the PIC16F687 is physically implemented and first 4k x
14 (0000h-0FFFh) for the PIC16F685/PIC16F689/
PIC16F690. Accessing a location above these
boundaries will cause a wrap around. The Reset vector
is at 0000h and the interrupt vector is at 0004h (see
Figures 2-1 and 2-2).
PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16F687
PC<12:0>
CALL, RETURN
RETFIE, RETLW
13
Stack Level 1
Stack Level 2
Stack Level 8
FIGURE 2-1:
PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16F685/689/690
Reset Vector
0000h
Interrupt Vector
0004h
0005h
PC<12:0>
CALL, RETURN
RETFIE, RETLW
On-chip Program
13
Memory
07FFh
Stack Level 1
0800h
Stack Level 2
Access 0-7FFh
1FFFh
Stack Level 8
Reset Vector
0000h
Interrupt Vector
0004h
0005h
On-chip Program
Memory
0FFFh
1000h
Access 0-FFFh
1FFFh
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 15
PIC16F685/687/689/690
2.2
Data Memory Organization
The data memory (see Figures 2-3, 2-4 and 2-5) is
partitioned into four banks which contain the General
Purpose Registers (GPR) and the Special Function
Registers (SFR). The Special Function Registers are
located in the first 32 locations of each bank. Register
locations 20h-7Fh in Bank 0 and A0h-EFh (A0-BF,
PIC16F687 only) in Bank 1 are General Purpose
Registers, implemented as static RAM. Register
locations F0h-FFh in Bank 1, 170h-17Fh in Bank 2 and
1F0h-1FFh in Bank 3 point to addresses 70h-7Fh in
Bank 0. Other General Purpose Resisters (GPR) are
also available in Bank 1 and Bank 2, depending on the
device. Details are shown in Figures 2-3, 2-4 and 2-5.
All other RAM is unimplemented and returns ‘0’ when
read. RP<1:0> (STATUS<6:5>) are the bank select
bits:
RP1
RP0
0
0
→
Bank 0 is selected
0
1
→
Bank 1 is selected
1
0
→
Bank 2 is selected
1
1
→
Bank 3 is selected
2.2.1
GENERAL PURPOSE REGISTER
FILE
The register file is organized as 128 x 8 in the
PIC16F687 and 256 x 8 in the PIC16F685/PIC16F689/
PIC16F690. Each register is accessed, either directly or
indirectly, through the File Select Register (FSR) (see
Section 2.4 “Indirect Addressing, INDF and FSR
Registers”).
2.2.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers are registers used by
the CPU and peripheral functions for controlling the
desired operation of the device (see Tables 2-1, 2-2, 2-3
and 2-4). These registers are static RAM.
The special registers can be classified into two sets:
core and peripheral. The Special Function Registers
associated with the “core” are described in this section.
Registers related to the operation of peripheral features
are described in the section of that peripheral feature.
DS41262A-page 16
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 2-3:
PIC16F685 SPECIAL FUNCTION REGISTERS
File
Address
Indirect addr. (1)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
PCLATH
INTCON
PIR1
PIR2
TMR1L
TMR1H
T1CON
TMR2
T2CON
CCPR1L
CCPR1H
CCP1CON
PWM1CON
ECCPAS
ADRESH
ADCON0
File
Address
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
Indirect addr. (1)
OPTION_REG
PCL
STATUS
FSR
TRISA
TRISB
TRISC
0Dh
0Eh
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
20h
PIE2
PCON
OSCCON
OSCTUNE
PCLATH
INTCON
PIE1
PR2
WPUA
IOCA
WDTCON
ADRESL
ADCON1
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
Indirect addr. (1)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
8Dh
8Eh
8Fh
90h
91h
92h
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
A0h
EEADR
EEDATH
EEADRH
General
Purpose
Register
General
Purpose
Register
7Fh
Bank 0
Note 1:
accesses
70h-7Fh
Bank1
PCLATH
INTCON
EEDAT
WPUB
IOCB
VRCON
CM1CON0
CM2CON0
CM2CON1
ANSEL
ANSELH
File
Address
100h
101h
102h
103h
104h
105h
106h
107h
108h
109h
10Ah
10Bh
10Ch
Indirect addr. (1)
OPTION_REG
PCL
STATUS
FSR
TRISA
TRISB
TRISC
10Dh
10Eh
10Fh
110h
111h
112h
113h
114h
115h
116h
117h
118h
119h
11Ah
11Bh
11Ch
11Dh
11Eh
11Fh
120h
EECON2(1)
PCLATH
INTCON
EECON1
PSTRCON
SRCON
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
1A0h
General
Purpose
Register
80 Bytes
96 Bytes
File
Address
80 Bytes
EFh
F0h
FFh
accesses
70h-7Fh
Bank2
16Fh
170h
17Fh
accesses
70h-7Fh
1F0h
1FFh
Bank3
Unimplemented data memory locations, read as ‘0’.
Not a physical register.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 17
PIC16F685/687/689/690
FIGURE 2-4:
PIC16F687/PIC16F689 SPECIAL FUNCTION REGISTERS
File
Address
File
Address
File
Address
File
Address
Indirect addr. (1)
TMR0
PCL
STATUS
00h
01h
02h
03h
Indirect addr. (1)
OPTION_REG
PCL
STATUS
80h
81h
82h
83h
Indirect addr. (1)
TMR0
PCL
STATUS
100h
101h
102h
103h
Indirect addr. (1)
OPTION_REG
PCL
STATUS
180h
181h
182h
183h
FSR
PORTA
PORTB
PORTC
04h
05h
06h
07h
08h
09h
FSR
TRISA
TRISB
TRISC
84h
85h
86h
87h
88h
89h
FSR
PORTA
PORTB
PORTC
104h
105h
106h
107h
108h
109h
FSR
TRISA
TRISB
TRISC
184h
185h
186h
187h
188h
189h
PCLATH
INTCON
PIR1
0Ah
0Bh
0Ch
PCLATH
INTCON
PIE1
8Ah
8Bh
8Ch
PCLATH
INTCON
EEDAT
10Ah
10Bh
10Ch
PCLATH
INTCON
EECON1
18Ah
18Bh
18Ch
PIR2
0Dh
PIE2
8Dh
EEADR
10Dh
EECON2(1)
18Dh
TMR1L
0Eh
PCON
8Eh
EEDATH
(3)
10Eh
18Eh
EEADRH(3)
10Fh
110h
111h
112h
18Fh
190h
191h
192h
113h
114h
115h
116h
117h
118h
119h
193h
194h
195h
196h
197h
198h
199h
19Ah
19Bh
19Ch
19Dh
19Eh
TMR1H
T1CON
0Fh
10h
11h
12h
OSCCON
OSCTUNE
8Fh
90h
91h
92h
SSPBUF
SSPCON
13h
14h
15h
16h
17h
18h
19h
SSPADD(2)
SSPSTAT
WPUA
IOCA
WDTCON
TXSTA
SPBRG
93h
94h
95h
96h
97h
98h
99h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
20h
SPBRGH
BAUDCTL
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
RCSTA
TXREG
RCREG
ADRESH
ADCON0
General
Purpose
Register
General
Purpose
Register
32 Bytes
48 Bytes
(PIC16F689 only)
96 Bytes
7Fh
Bank 0
ADRESL
ADCON1
accesses
70h-7Fh
WPUB
IOCB
VRCON
CM1CON0
CM2CON0
CM2CON1
ANSEL
ANSELH
A0h
BFh
C0h
11Ah
11Bh
11Ch
11Dh
11Eh
11Fh
SRCON
19Fh
1A0h
120h
General
Purpose
Register
80 Bytes
(PIC16F689 only)
EFh
F0h
FFh
Bank1
accesses
70h-7Fh
Bank2
170h
17Fh
accesses
70h-7Fh
1F0h
1FFh
Bank3
Unimplemented data memory locations, read as ‘0’.
Note 1:
2:
3:
Not a physical register.
Address 93h also accesses the SSP Mask (SSPMSK) register under certain conditions.
See Registers 13-2 and 13-3 for more details.
PIC16F689 only.
DS41262A-page 18
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 2-5:
PIC16F690 SPECIAL FUNCTION REGISTERS
File
Address
Indirect addr. (1)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
File
Address
Indirect addr. (1)
OPTION_REG
PCL
STATUS
FSR
TRISA
TRISB
TRISC
PCLATH
INTCON
PIR1
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
PIR2
TMR1L
TMR1H
T1CON
TMR2
T2CON
0Dh
0Eh
0Fh
10h
11h
12h
PIE2
PCON
OSCCON
OSCTUNE
SSPBUF
SSPCON
CCPR1L
CCPR1H
CCP1CON
RCSTA
TXREG
RCREG
13h
14h
15h
16h
17h
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh
1Fh
20h
SSPADD(2)
SSPSTAT
WPUA
IOCA
WDTCON
TXSTA
SPBRG
SPBRGH
BAUDCTL
PWM1CON
ECCPAS
ADRESH
ADCON0
PCLATH
INTCON
PIE1
PR2
ADRESL
ADCON1
80h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
Indirect addr. (1)
TMR0
PCL
STATUS
FSR
PORTA
PORTB
PORTC
8Dh
8Eh
8Fh
90h
91h
92h
EEADR
EEDATH
EEADRH
93h
94h
95h
96h
97h
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
9Fh
A0h
General
Purpose
Register
General
Purpose
Register
7Fh
Bank 0
Note 1:
2:
accesses
70h-7Fh
Bank1
PCLATH
INTCON
EEDAT
WPUB
IOCB
VRCON
CM1CON0
CM2CON0
CM2CON1
ANSEL
ANSELH
File
Address
100h
101h
102h
103h
104h
105h
106h
107h
108h
109h
10Ah
10Bh
10Ch
Indirect addr. (1)
OPTION_REG
PCL
STATUS
FSR
TRISA
TRISB
TRISC
10Dh
10Eh
10Fh
110h
111h
112h
EECON2(1)
113h
114h
115h
116h
117h
118h
119h
11Ah
11Bh
11Ch
11Dh
11Eh
11Fh
120h
PCLATH
INTCON
EECON1
PSTRCON
SRCON
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
1A0h
General
Purpose
Register
80 Bytes
96 Bytes
File
Address
80 Bytes
EFh
F0h
FFh
accesses
70h-7Fh
Bank2
16Fh
170h
17Fh
accesses
70h-7Fh
1F0h
1FFh
Bank3
Unimplemented data memory locations, read as ‘0’.
Not a physical register.
Address 93h also accesses the SSP Mask (SSPMSK) register under certain conditions.
See Registers 13-2 and 13-3 for more details.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 19
PIC16F685/687/689/690
TABLE 2-1:
Addr
PIC16F685/687/689/690 SPECIAL REGISTERS SUMMARY BANK 0
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR/BOR
Reset
Value on
all other
Resets(1)
Bank 0
00h
INDF
Addressing this location uses contents of FSR to address data memory (not a physical register)
xxxx xxxx xxxx xxxx
01h
TMR0
Timer0 Module Register
xxxx xxxx uuuu uuuu
02h
PCL
Program Counter’s (PC) Least Significant Byte
03h
STATUS
04h
FSR
05h
PORTA
—
—
06h
PORTB
RB7
07h
PORTC
RC7
08h
—
Unimplemented
—
—
09h
—
Unimplemented
—
—
0Ah
PCLATH
—
—
—
0Bh
INTCON
GIE
PEIE
T0IE
INTE
RABIE
0Ch
PIR1
—
ADIF
RCIF(3)
TXIF(3)
SSPIF(3)
0Dh
PIR2
OSFIF
C2IF
C1IF
EEIF
—
0Eh
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1
xxxx xxxx uuuu uuuu
0Fh
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1
xxxx xxxx uuuu uuuu
IRP
RP1
RP0
0000 0000 0000 0000
TO
PD
Z
DC
C
RA5
RA4
RA3
RA2
RA1
RA0
--xx xxxx --uu uuuu
RB6
RB5
RB4
—
—
—
—
xxxx ---- uuuu ----
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx uuuu uuuu
Indirect Data Memory Address Pointer
Write Buffer for upper 5 bits of Program Counter
T0IF
INTF
CCP1IF(4) TMR2IF(4)
—
—
---0 0000 ---0 0000
RABIF(2)
0000 000x 0000 000x
TMR1IF
-000 0000 -000 0000
—
0000 ---- 0000 ----
10h
T1CON
TMR2
12h
T2CON
13h
SSPBUF(3)
14h
SSPCON(3, 5)
15h
CCPR1L(4)
16h
CCPR1H
(4)
17h
CCP1CON(4)
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
0000 0000 0000 0000
18h
RCSTA(3)
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x 0000 000x
19h
TXREG(3)
1Ah
(3)
RCREG
1Bh
—
1Ch
PWM1CON(4)
1Dh
ECCPAS(4)
ECCPASE ECCPAS2
1Eh
ADRESH
A/D Result Register High Byte
1Fh
ADCON0
3:
4:
5:
TMR1GE
xxxx xxxx uuuu uuuu
11h
Legend:
Note 1:
2:
T1GINV
0001 1xxx 000q quuu
T1CKPS1
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON 0000 0000 uuuu uuuu
TOUTPS2
TOUTPS1
TOUTPS0
TMR2ON
T2CKPS1
T2CKPS0 -000 0000 -000 0000
SSPM2
SSPM1
Timer2 Module Register
—
TOUTPS3
0000 0000 0000 0000
Synchronous Serial Port Receive Buffer/Transmit Register
WCOL
SSPOV
SSPEN
CKP
SSPM3
xxxx xxxx uuuu uuuu
SSPM0
Capture/Compare/PWM Register 1 (LSB)
0000 0000 0000 0000
xxxx xxxx uuuu uuuu
Capture/Compare/PWM Register 1 (MSB)
xxxx xxxx uuuu uuuu
EUSART Transmit Data Register
0000 0000 0000 0000
EUSART Receive Data Register
0000 0000 0000 0000
Unimplemented
PRSEN
ADFM
PDC6
VCFG
—
—
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
0000 0000 0000 0000
ECCPAS1
ECCPAS0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
0000 0000 0000 0000
CHS2
CHS1
CHS0
GO/DONE
ADON
0000 0000 0000 0000
CHS3
xxxx xxxx uuuu uuuu
– = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented
Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
MCLR and WDT Reset do not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the
mismatched exists.
PIC16F687/PIC16F689/PIC16F690 only.
PIC16F685/PIC16F690 only.
When SSPCON bits SSPM<3:0> = 1001, any reads or writes to the SSPADD SFR address are accessed through the SSPMSK register.
See Registers 13-2 and 13-3 for more detail.
DS41262A-page 20
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 2-2:
Addr
PIC16F685/687/689/690 SPECIAL FUNCTION REGISTERS SUMMARY BANK 1
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR/BOR
Reset
Value on
all other
Resets(1)
xxxx xxxx
xxxx xxxx
1111 1111
1111 1111
Bank 1
80h
INDF
Addressing this location uses contents of FSR to address data memory (not a physical
register)
81h
OPTION_REG
82h
PCL
83h
STATUS
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
Program Counter’s (PC) Least Significant Byte
IRP
RP1
RP0
0000 0000
0000 0000
000q quuu
TO
PD
Z
DC
C
0001 1xxx
xxxx xxxx
uuuu uuuu
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
--11 1111
--11 1111
84h
FSR
85h
TRISA
Indirect Data Memory Address Pointer
86h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
87h
TRISC
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111
1111 1111
—
—
—
TRISA5
88h
—
Unimplemented
—
89h
—
Unimplemented
—
—
8Ah
PCLATH
—
—
—
---0 0000
---0 0000
8Bh
INTCON
GIE
PEIE
T0IE
0000 000x
0000 000x
(3)
INTE
RABIE
PIE1
—
ADIE
PIE2
OSFIE
C2IE
8Eh
PCON
—
—
8Fh
OSCCON
—
IRCF2
IRCF1
IRCF0
90h
OSCTUNE
—
—
—
TUN4
TUN3
—
EEIE
ULPWUE SBOREN
SSPIE
(3)
8Ch
C1IE
TXIE
(3)
8Dh
91h
RCIE
Write Buffer for the upper 5 bits of the Program Counter
T0IF
CCP1IE
RABIF(2)
INTF
(4)
TMR1IE
-000 0000
-000 0000
—
—
—
0000 ----
0000 ----
—
—
POR
BOR
--01 --qq
--0u --uu
OSTS
HTS
LTS
SCS
-110 q000
-110 x000
TUN2
TUN1
TUN0
---0 0000
---u uuuu
—
TMR2IE
(4)
Unimplemented
92h
PR2(4)
Timer2 Period Register
93h
SSPADD(3, 6)
Synchronous Serial Port (I2C mode) Address Register
93h
SSPMSK(3, 6)
(3)
MSK7
MSK6
MSK5
MSK4
MSK3
MSK2
MSK1
—
—
1111 1111
1111 1111
0000 0000
0000 0000
MSK0
1111 1111
1111 1111
0000 0000
94h
SSPSTAT
SMP
CKE
D/A
P
S
R/W
UA
BF
0000 0000
95h
WPUA(5)
—
—
WPUA5
WPUA4
—
WPUA2
WPUA1
WPUA0
--11 -111
--11 -111
96h
IOCA
—
—
IOCA5
IOCA4
IOCA3
IOCA2
IOCA1
IOCA0
--00 0000
--00 0000
97h
WDTCON
—
—
—
WDTPS3
WDTPS2
WDTPS1
WDTPS0
SWDTEN
---0 1000
---0 1000
98h
TXSTA(3)
CSRC
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
99h
SPBRG(3)
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
BRG15
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
—
(3)
9Ah
SPBRGH
9Bh
BAUDCTL(3)
9Ch
—
Unimplemented
—
9Dh
—
Unimplemented
—
—
9Eh
ADRESL
xxxx xxxx
uuuu uuuu
9Fh
ADCON1
-000 ----
-000 ---
Legend:
Note 1:
2:
3:
4:
5:
6:
A/D Result Register Low Byte
—
ADCS2
ADCS1
ADCS0
—
—
—
—
– = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented
Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
MCLR and WDT Reset do not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the
mismatched exists.
PIC16F687/PIC16F689/PIC16F690 only.
PIC16F685/PIC16F690 only.
RA3 pull-up is enabled when pin is configured as MCLR in Configuration Word.
Accessible only when SSPM<3:0> = 1001.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 21
PIC16F685/687/689/690
TABLE 2-3:
Addr
PIC16F685/687/689/690 SPECIAL REGISTERS SUMMARY BANK 2
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR/BOR
Reset
Value on
all other
Resets(1)
Bank 2
100h
INDF
Addressing this location uses contents of FSR to address data memory (not a physical register)
xxxx xxxx xxxx xxxx
101h
TMR0
Timer0 Module Register
xxxx xxxx uuuu uuuu
102h
PCL
Program Counter’s (PC) Least Significant Byte
103h
STATUS
IRP
RP1
RP0
0000 0000 0000 0000
TO
PD
Z
DC
C
0001 1xxx 000q quuu
RA4
RA3
RA2
RA1
RA0
--xx xxxx --uu uuuu
104h
FSR
105h
PORTA
Indirect Data Memory Address Pointer
106h
PORTB
RB7
RB6
RB5
RB4
—
—
—
—
xxxx ---- uuuu ----
107h
PORTC
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx uuuu uuuu
108h
—
Unimplemented
—
—
109h
—
Unimplemented
—
—
—
—
RA5
xxxx xxxx uuuu uuuu
10Ah PCLATH
—
—
—
10Bh INTCON
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF(2)
0000 000x 0000 000x
10Ch EEDAT
EEDAT7
EEDAT6
EEDAT5
EEDAT4
EEDAT3
EEDAT2
EEDAT1
EEDAT0
0000 0000 0000 0000
10Dh EEADR
EEADR7
EEADR6
EEADR5
EEADR4
EEADR3
EEADR2
EEADR1
EEADR0
0000 0000 0000 0000
(3)
—
—
EEDATH3
EEDATH2
EEDATH1
EEDATH0 --00 0000 --00 0000
10Fh EEADRH(3)
—
—
10Eh EEDATH
Write Buffer for the upper 5 bits of the Program Counter
EEDATH5 EEDATH4
—
—
---0 0000 ---0 0000
EEADRH3 EEADRH2 EEADRH1 EEADRH0 ---- 0000 ---- 0000
110h
—
Unimplemented
—
—
111h
—
Unimplemented
—
—
112h
—
Unimplemented
—
—
113h
—
Unimplemented
—
—
114h
—
Unimplemented
—
—
115h
WPUB
116h
IOCB
117h
—
118h
VRCON
WPUB7
WPUB6
WPUB5
WPUB4
—
—
—
—
1111 ---- 1111 ----
IOCB7
IOCB6
IOCB5
IOCB4
—
—
—
—
0000 ---- 0000 ----
C2VREN
VRR
VP6EN
VR3
VR2
VR1
VR0
0000 0000 0000 0000
Unimplemented
C1VREN
—
—
119h
CM1CON0
C1ON
C1OUT
C1OE
C1POL
—
C1R
C1CH1
C1CH0
0000 -000 0000 -000
11Ah
CM2CON0
C2ON
C2OUT
C2OE
C2POL
—
C2R
C2CH1
C2CH0
0000 -000 0000 -000
11Bh
CM2CON1
MC1OUT
MC2OUT
—
—
—
—
T1GSS
C2SYNC
00-- --10 00-- --10
11Ch
—
Unimplemented
—
—
11Dh
—
Unimplemented
—
—
11Eh
ANSEL
11Fh
ANSELH
Legend:
Note 1:
2:
3:
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
1111 1111 1111 1111
—
—
—
—
ANS11
ANS10
ANS9
ANS8
---- 1111 ---- 1111
– = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented
Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
MCLR and WDT Reset does not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the
mismatched exists.
PIC16F685/PIC16F689/PIC16F690 only.
DS41262A-page 22
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 2-4:
Addr
PIC16F685/687/689/690 SPECIAL FUNCTION REGISTERS SUMMARY BANK 3
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR/BOR
Reset
Value on
all other
Resets(1)
xxxx xxxx
xxxx xxxx
1111 1111
1111 1111
0000 0000
0000 0000
0001 1xxx
000q quuu
Bank 3
180h
INDF
Addressing this location uses contents of FSR to address data memory (not a physical
register)
181h
OPTION_REG
182h
PCL
183h
STATUS
184h
FSR
185h
TRISA
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
Program Counter’s (PC) Least Significant Byte
IRP
RP1
RP0
TO
PD
Z
DC
C
Indirect Data Memory Address Pointer
—
—
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
xxxx xxxx
uuuu uuuu
--11 1111
--11 1111
186h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
187h
TRISC
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111
1111 1111
—
188h
—
Unimplemented
—
189h
—
Unimplemented
—
—
18Ah
PCLATH
—
—
—
---0 0000
---0 0000
18Bh
INTCON
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF(2)
0000 000x
0000 000x
18Ch
EECON1
EEPGD
—
—
—
WRERR
WREN
WR
RD
x--- x000
0--- q000
18Dh
EECON2
---- ----
---- ----
Write Buffer for the upper 5 bits of the Program Counter
EEPROM Control Register 2 (not a physical register)
18Eh
—
Unimplemented
—
—
18Fh
—
Unimplemented
—
—
190h
—
Unimplemented
—
—
191h
—
Unimplemented
—
—
192h
—
Unimplemented
—
—
193h
—
Unimplemented
—
—
194h
—
Unimplemented
—
—
195h
—
Unimplemented
—
—
196h
—
Unimplemented
—
—
197h
—
Unimplemented
—
—
198h
—
Unimplemented
—
—
199h
—
Unimplemented
—
—
19Ah
—
Unimplemented
—
—
19Bh
—
Unimplemented
—
—
19Ch
—
Unimplemented
—
—
19Dh
PSTRCON(3)
19Eh
SRCON
19Fh
—
Legend:
Note 1:
2:
3:
—
—
—
STRSYNC
STRD
STRC
STRB
STRA
---0 0001
---0 0001
SR1
SR0
C1SEN
C2REN
PULSS
PULSR
—
—
0000 00--
0000 00--
—
—
Unimplemented
– = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented
Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
MCLR and WDT Reset does not affect the previous value data latch. The RABIF bit will be cleared upon Reset but will set again if the
mismatched exists.
PIC16F685/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 23
PIC16F685/687/689/690
2.2.2.1
Status Register
The Status register, shown in Register 2-1, contains:
• the arithmetic status of the ALU
• the Reset status
• the bank select bits for data memory (GPR and
SFR)
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).
The Status register can be the destination for any
instruction, like any other register. If the Status register
is the destination for an instruction that affects the Z,
DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not
REGISTER 2-1:
writable. Therefore, the result of an instruction with the
Status register as destination may be different than
intended.
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
any Status bits. For other instructions not affecting any
Status bits, see the “Instruction Set Summary.”
Note 1: The C and DC bits operate as a Borrow
and Digit Borrow out bit, respectively, in
subtraction. See the SUBLW and SUBWF
instructions for examples.
STATUS – STATUS REGISTER (ADDRESS: 03h, 83h, 103h OR 183h)
R/W-0
R/W-0
R/W-0
R-1
R-1
R/W-x
R/W-x
R/W-x
IRP
RP1
RP0
TO
PD
Z
DC(1)
C(1)
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
RP<1:0>: Register Bank Select bits (used for direct addressing)
00 = Bank 0 (00h-7Fh)
01 = Bank 1 (80h-FFh)
10 = Bank 2 (100h-17Fh)
11 = Bank 3 (180h-1FFh)
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)
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)
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 1: For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s
complement of the second operand. For rotate (RRF, RLF) instructions, this bit is
loaded with either the high or low-order bit of the source register.
Legend:
DS41262A-page 24
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
2.2.2.2
OPTION Register
Note:
The OPTION register is a readable and writable
register, which contains various control bits to
configure:
•
•
•
•
To achieve a 1:1 prescaler assignment for
TMR0, assign the prescaler to the WDT by
setting PSA bit to ‘1’ (OPTION_REG<3>).
See Section 5.4 “Prescaler”.
TMR0/WDT prescaler
External RA2/INT interrupt
TMR0
Weak pull-ups on PORTA/PORTB
REGISTER 2-2:
OPTION_REG – OPTION REGISTER (ADDRESS: 81h OR 181h)
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
bit 7
bit 0
bit 7
RABPU: PORTA/PORTB Pull-up Enable bit
1 = PORTA/PORTB pull-ups are disabled
0 = PORTA/PORTB pull-ups are enabled by individual port latch values
bit 6
INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of RA2/AN2/T0CKI/INT/C1OUT pin
0 = Interrupt on falling edge of RA2/AN2/T0CKI/INT/C1OUT pin
bit 5
T0CS: TMR0 Clock Source Select bit
1 = Transition on RA2/AN2/T0CKI/INT/C1OUT pin
0 = Internal instruction cycle clock (CLKOUT)
bit 4
T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on RA2/AN2/T0CKI/INT/C1OUT pin
0 = Increment on low-to-high transition on RA2/AN2/T0CKI/INT/C1OUT 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
PS<2:0>: Prescaler Rate Select bits
Bit Value
000
001
010
011
100
101
110
111
TMR0 Rate
WDT Rate(1)
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
Note 1: A dedicated 16-bit WDT postscaler is available. See Section 14.5 “Watchdog
Timer (WDT)” for more information.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 25
PIC16F685/687/689/690
2.2.2.3
INTCON Register
Note:
The INTCON register is a readable and writable
register, which contains the various enable and flag bits
for TMR0 register overflow, PORTA change and
external RA2/AN2/T0CKI/INT/C1OUT pin interrupts.
REGISTER 2-3:
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
software should ensure the appropriate
interrupt flag bits are clear prior to
enabling an interrupt.
INTCON – INTERRUPT CONTROL REGISTER (ADDRESS: 0Bh, 8Bh, 10Bh OR
18Bh)
R/W-0
GIE
R/W-0
PEIE
R/W-0
T0IE
R/W-0
INTE
R/W-0
(1,3)
RABIE
R/W-0
R/W-0
R/W-x
T0IF(2)
INTF
RABIF
bit 7
bit 0
bit 7
GIE: Global Interrupt Enable bit
1 = Enables all unmasked interrupts
0 = Disables all interrupts
bit 6
PEIE: Peripheral Interrupt Enable bit
1 = Enables all unmasked peripheral interrupts
0 = Disables all peripheral interrupts
bit 5
T0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 interrupt
0 = Disables the TMR0 interrupt
bit 4
INTE: RA2/INT External Interrupt Enable bit
1 = Enables the RA2/INT external interrupt
0 = Disables the RA2/INT external interrupt
bit 3
RABIE: PORTA/PORTB Change Interrupt Enable bit(1, 3)
1 = Enables the PORTA/PORTB change interrupt
0 = Disables the PORTA/PORTB change interrupt
bit 2
T0IF: TMR0 Overflow Interrupt Flag bit(2)
1 = TMR0 register has overflowed (must be cleared in software)
0 = TMR0 register did not overflow
bit 1
INTF: RA2/INT External Interrupt Flag bit
1 = The RA2/INT external interrupt occurred (must be cleared in software)
0 = The RA2/INT external interrupt did not occur
bit 0
RABIF: PORTA/PORTB Change Interrupt Flag bit
1 = When at least one of the PORTA or PORTB general purpose I/O pins changed state (must
be cleared in software)
0 = None of the PORTA or PORTB general purpose I/O pins have changed state
Note 1: IOCA or IOCB register must also be enabled.
2: T0IF bit is set when Timer0 rolls over. Timer0 is unchanged on Reset and should
be initialized before clearing T0IF bit.
3: Includes ULPWU interrupt.
Legend:
DS41262A-page 26
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
2.2.2.4
PIE1 Register
The PIE1 register contains the interrupt enable bits, as
shown in Register 2-4.
REGISTER 2-4:
Note:
Bit PEIE (INTCON<6>) must be set to
enable any peripheral interrupt.
PIE1 – PERIPHERAL INTERRUPT ENABLE REGISTER 1 (ADDRESS: 8Ch)
U-0
R/W-0
R/W-0
R/W-0
R/W-0
—
ADIE
RCIE(2)
TXIE(2)
SSPIE(2)
R/W-0
R/W-0
CCP1IE(1) TMR2IE(1)
bit 7
R/W-0
TMR1IE
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
ADIE: A/D Converter Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 5
RCIE: EUSART Receive Interrupt Enable bit(2)
1 = Enabled
0 = Disabled
bit 4
TXIE: EUSART Transmit Interrupt Enable bit(2)
1 = Enabled
0 = Disabled
bit 3
SSPIE: Synchronous Serial Port (SSP) Interrupt Enable bit(2)
1 = Enabled
0 = Disabled
bit 2
CCP1IE: CCP1 Interrupt Enable bit(1)
1 = Enabled
0 = Disabled
bit 1
TMR2IE: TMR2 to PR2 Match Interrupt Enable bit(1)
1 = Enabled
0 = Disabled
bit 0
TMR1IE: TMR1 Overflow Interrupt Enable bit
1 = Enabled
0 = Disabled
Note 1: PIC16F685/PIC16F690 only.
2: PIC16F687/PIC16F689/PIC16F690 only.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 27
PIC16F685/687/689/690
2.2.2.5
PIE2 Register
The PIE2 register contains the interrupt enable bits, as
shown in Register 2-5.
REGISTER 2-5:
Note:
Bit PEIE (INTCON<6>) must be set to
enable any peripheral interrupt.
PIE2 – PERIPHERAL INTERRUPT ENABLE REGISTER 2 (ADDRESS: 8Dh)
R/W-0
R/W-0
R/W-0
R/W-0
U-0
U-0
U-0
U-0
OSFIE
C2IE
C1IE
EEIE
—
—
—
—
bit 7
bit 0
bit 7
OSFIE: Oscillator Fail Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 6
C2IE: Comparator 2 Interrupt Enable bit
1 = Enables Comparator 2 interrupt
0 = Disables Comparator 2 interrupt
bit 5
C1IE: Comparator 1 Interrupt Enable bit
1 = Enables Comparator 1 interrupt
0 = Disables Comparator 1 interrupt
bit 4
EEIE: EE Write Operation Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 3-0
Unimplemented: Read as ‘0’
Legend:
DS41262A-page 28
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
2.2.2.6
PIR1 Register
The PIR1 register contains the interrupt flag bits, as
shown in Register 2-6.
REGISTER 2-6:
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
software should ensure the appropriate
interrupt flag bits are clear prior to
enabling an interrupt.
PIR1 – PERIPHERAL INTERRUPT REQUEST REGISTER 1 (ADDRESS: 0Ch)
U-0
R/W-0
R-0
R-0
R/W-0
—
ADIF
RCIF(1)
TXIF(1)
SSPIF(1)
R/W-0
R/W-0
CCP1IF(2) TMR2IF(2)
R/W-0
TMR1IF
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
ADIF: A/D Converter Interrupt Flag bit
1 = The A/D conversion completed (must be cleared in software)
0 = The A/D conversion is not complete
bit 5
RCIF: EUSART Receive Interrupt Flag bit(1)
1 = The EUSART receive buffer is full (cleared by reading RCREG)
0 = The EUSART receive buffer is not full
bit 4
TXIF: EUSART Transmit Interrupt Flag bit(1)
1 = The EUSART transmit buffer is empty (cleared by writing to TXREG)
0 = The EUSART transmit buffer is full
bit 3
SSPIF: Synchronous Serial Port (SSP) Interrupt Flag bit(1)
1 = The Transmission/Reception is complete (must be cleared in software)
0 = Waiting to Transmit/Receive
bit 2
CCP1IF: CCP1 Interrupt Flag bit(2)
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 Interrupt Flag bit(2)
1 = A 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 = The TMR1 register overflowed (must be cleared in software)
0 = The TMR1 register did not overflow
Note 1: PIC16F687/PIC16F689/PIC16F690 only.
2: PIC16F685/PIC16F690 only.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 29
PIC16F685/687/689/690
2.2.2.7
PIR2 Register
The PIR2 register contains the interrupt flag bits, as
shown in Register 2-7.
REGISTER 2-7:
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
software should ensure the appropriate
interrupt flag bits are clear prior to enabling
an interrupt.
PIR2 – PERIPHERAL INTERRUPT REQUEST REGISTER 2 (ADDRESS: 0Dh)
R/W-0
R/W-0
R/W-0
R/W-0
U-0
U-0
U-0
U-0
OSFIF
C2IF
C1IF
EEIF
—
—
—
—
bit 7
bit 0
bit 7
OSFIF: Oscillator Fail Interrupt Flag bit
1 = System oscillator failed, clock input has changed to INTOSC (must be cleared in software)
0 = System clock operating
bit 6
C2IF: Comparator 2 Interrupt Flag bit
1 = Comparator output (C2OUT bit) has changed (must be cleared in software)
0 = Comparator output (C2OUT bit) has not changed
bit 5
C1IF: Comparator 1 Interrupt Flag bit
1 = Comparator output (C1OUT bit) has changed (must be cleared in software)
0 = Comparator output (C1OUT bit) has not changed
bit 4
EEIF: EE Write Operation Interrupt Flag bit
1 = Write operation completed (must be cleared in software)
0 = Write operation has not completed or has not started
bit 3-0
Unimplemented: Read as ‘0’
Legend:
DS41262A-page 30
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
2.2.2.8
PCON Register
The Power Control (PCON) register (see Register 2-8)
contains flag bits to differentiate between a:
•
•
•
•
Power-on Reset (POR)
Brown-out Reset (BOR)
Watchdog Timer Reset (WDT)
External MCLR Reset
The PCON register also controls the Ultra Low-Power
Wake-up and software enable of the BOR.
REGISTER 2-8:
PCON — POWER CONTROL REGISTER (ADDRESS: 8Eh)
U-0
—
U-0
—
R/W-0
R/W-1
ULPWUE SBOREN
(1)
U-0
U-0
R/W-0
R/W-x
—
—
POR
BOR
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5
ULPWUE: Ultra Low-Power Wake-up Enable bit
1 = Ultra Low-Power Wake-up enabled
0 = Ultra Low-Power Wake-up disabled
bit 4
SBOREN: Software BOR Enable bit(1)
1 = BOR enabled
0 = BOR disabled
bit 3-2
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)
Note 1: BOREN<1:0> = 01 in the Configuration Word register for this bit to control the BOR.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 31
PIC16F685/687/689/690
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 high byte (PC<12:8>) is not directly
readable or writable and comes from PCLATH. On any
Reset, the PC is cleared. Figure 2-6 shows the two
situations for the loading of the PC. The upper example
in Figure 2-6 shows how the PC is loaded on a write to
PCL (PCLATH<4:0> → PCH). The lower example in
Figure 2-6 shows how the PC is loaded during a CALL or
GOTO instruction (PCLATH<4:3> → PCH).
FIGURE 2-6:
12
8
7
0
Instruction with
PCL as
Destination
8
PCLATH<4:0>
ALU Result
PCLATH
PCH
11 10
PCL
8
0
7
PC
GOTO, CALL
2
PCLATH<4:3>
11
OPCODE<10:0>
COMPUTED GOTO
A computed GOTO is accomplished by adding an offset
to the program counter (ADDWF PCL). When performing
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 AN556, “Implementing a Table Read”
(DS00556).
2.3.2
Indirect Addressing, INDF and
FSR Registers
The INDF register is not a physical register. Addressing
the INDF register will cause indirect addressing.
Indirect addressing is possible by using the INDF
register. Any instruction using the INDF register actually
accesses data pointed to by the File Select Register
(FSR). Reading INDF itself indirectly will produce 00h.
Writing to the INDF register indirectly results in a no
operation (although Status bits may be affected). An
effective 9-bit address is obtained by concatenating the
8-bit FSR and the IRP bit (STATUS<7>), as shown in
Figure 2-7.
A simple program to clear RAM location 20h-2Fh using
indirect addressing is shown in Example 2-1.
PCLATH
2.3.1
2: There are no instructions/mnemonics
called PUSH or POP. These are actions
that occur from the execution of the
CALL, RETURN, RETLW and RETFIE
instructions or the vectoring to an
interrupt address.
2.4
PCL
PC
12
Note 1: There are no Status bits to indicate stack
overflow or stack underflow conditions.
LOADING OF PC IN
DIFFERENT SITUATIONS
PCH
5
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).
EXAMPLE 2-1:
MOVLW
MOVWF
NEXT
CLRF
INCF
BTFSS
GOTO
CONTINUE
INDIRECT ADDRESSING
0x20
FSR
INDF
FSR
FSR,4
NEXT
;initialize pointer
;to RAM
;clear INDF register
;inc pointer
;all done?
;no clear next
;yes continue
STACK
The PIC16F685/687/689/690 devices have an
8-level x 13-bit wide hardware stack (see Figures 2-1
and 2-2). The stack space is not part of either program
or data space and the Stack Pointer is not readable or
writable. The PC is PUSHed onto the stack when a
CALL instruction is executed or an interrupt causes a
branch. The stack is POPed in the event of a RETURN,
RETLW or a RETFIE instruction execution. PCLATH is
not affected by a PUSH or POP operation.
DS41262A-page 32
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 2-7:
DIRECT/INDIRECT ADDRESSING PIC16F685/687/689/690
Direct Addressing
RP1 RP0
Bank Select
6
From Opcode
Indirect Addressing
0
IRP
7
Bank Select
Location Select
00
01
10
File Select Register
0
Location Select
11
00h
180h
Data
Memory
7Fh
1FFh
Bank 0
Bank 1
Bank 2
Bank 3
For memory map detail, see Figures 2-3, 2-4 and 2-5.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 33
PIC16F685/687/689/690
NOTES:
DS41262A-page 34
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
3.0
CLOCK SOURCES
The PIC16F685/687/689/690 can be configured in one
of eight clock modes.
3.1
Overview
1.
2.
3.
The PIC16F685/687/689/690 devices have a wide
variety of clock sources and selection features to allow
it to be used in a wide range of applications while
maximizing performance and minimizing power
consumption. Figure 3-1 illustrates a block diagram of
the PIC16F685/687/689/690 clock sources.
4.
5.
Clock sources can be configured from external
oscillators, quartz crystal resonators, ceramic resonators
and Resistor-Capacitor (RC) circuits. In addition, the
system clock source can be configured from one of two
internal oscillators, with a choice of speeds selectable via
software. Additional clock features include:
6.
7.
8.
• Selectable system clock source between external
or internal via software.
• Two-Speed Clock Start-up mode, which
minimizes latency between external oscillator
start-up and code execution.
• Fail-Safe Clock Monitor (FSCM) designed to
detect a failure of the external clock source (LP,
XT, HS, EC or RC modes) and switch to the
internal oscillator.
FIGURE 3-1:
EC – External clock with I/O on RA4.
LP – 32 kHz low-power Crystal mode.
XT – Medium gain Crystal or Ceramic Resonator
Oscillator mode.
HS – High gain Crystal or Ceramic Resonator
mode.
RC – External Resistor-Capacitor (RC) with
FOSC/4 output on RA4.
RCIO – External Resistor-Capacitor with I/O on
RA4.
INTOSC – Internal oscillator with FOSC/4 output
on RA4 and I/O on RA5.
INTOSCIO – Internal oscillator with I/O on RA4
and RA5.
Clock Source modes are configured by the FOSC<2:0>
bits in the Configuration Word register (see Section 14.0
“Special Features of the CPU”). The internal clock can
be generated from two internal oscillators. The
HFINTOSC is a high-frequency calibrated oscillator. The
LFINTOSC is a low-frequency uncalibrated oscillator.
PIC16F685/687/689/690 CLOCK SOURCE BLOCK DIAGRAM
FOSC<2:0>
(Configuration Word)
SCS
(OSCCON<0>)
External Oscillator
OSC2
Sleep
MUX
LP, XT, HS, RC, RCIO, EC
OSC1
IRCF<2:0>
(OSCCON<6:4>)
8 MHz
Internal Oscillator
4 MHz
System Clock
(CPU and Peripherals)
INTOSC
111
110
101
1 MHz
100
500 kHz
250 kHz
125 kHz
LFINTOSC
31 kHz
31 kHz
011
MUX
HFINTOSC
8 MHz
Postscaler
2 MHz
010
001
000
Power-up Timer (PWRT)
Watchdog Timer (WDT)
Fail-Safe Clock Monitor (FSCM)
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 35
PIC16F685/687/689/690
3.2
Clock Source Modes
Clock Source modes can be classified as external or
internal.
External Clock Modes
3.3.1
OSCILLATOR START-UP TIMER (OST)
If the PIC16F685/687/689/690 is configured for LP, XT
or HS modes, the Oscillator Start-up Timer (OST)
counts 1024 oscillations from the OSC1 pin, following a
Power-on Reset (POR) and the Power-up Timer
(PWRT) has expired (if configured), or a wake-up from
Sleep. During this time, the program counter does not
increment and program execution is suspended. The
OST ensures that the oscillator circuit, using a quartz
crystal resonator or ceramic resonator, has started and
is providing a stable system clock to the PIC16F685/
687/689/690. When switching between clock sources a
delay is required to allow the new clock to stabilize.
These oscillator delays are shown in Table 3-1.
• External Clock modes rely on external circuitry for
the clock source. Examples are oscillator modules
(EC mode), quartz crystal resonators or ceramic
resonators (LP, XT and HS modes), and
Resistor-Capacitor (RC mode) circuits.
• Internal clock sources are contained internally
within the PIC16F685/687/689/690. The
PIC16F685/687/689/690 has two internal
oscillators, the 8 MHz High-Frequency Internal
Oscillator (HFINTOSC) and 31 kHz
Low-Frequency Internal Oscillator (LFINTOSC).
The system clock can be selected between external or
internal clock sources via the System Clock Selection
(SCS) bit (see Section 3.5 “Clock Switching”).
TABLE 3-1:
3.3
In order to minimize latency between external
oscillator start-up and code execution, the Two-Speed
Clock Start-up mode can be selected (see Section 3.6
“Two-Speed Clock Start-up Mode”).
OSCILLATOR DELAY EXAMPLES
Switch From
Switch To
Frequency
Sleep/POR
LFINTOSC
HFINTOSC
31 kHz
125 kHz to 8 MHz
Sleep/POR
EC, RC
DC – 20 MHz
LFINTOSC (31 kHz)
EC, RC
DC – 20 MHz
Oscillator Delay
5 μs-10 μs (approx.) CPU Start-up(1)
Sleep/POR
LP, XT, HS
32 kHz to 20 MHz
1024 Clock Cycles (OST)
LFINTOSC (31 kHz)
HFINTOSC
125 kHz to 8 MHz
1 μs (approx.)
Note 1:
3.3.2
The 5 μs to 10 μs start-up delay is based on a 1 MHz system clock.
EC MODE
FIGURE 3-2:
The External Clock (EC) mode allows an externally
generated logic level as the system clock source. When
operating in this mode, an external clock source is
connected to the OSC1 pin and the RA4/AN3/T1G/
OSC2/CLKOUT pin is available for general purpose I/O.
Figure 3-2 shows the pin connections for EC mode.
Clock from
Ext. System
The Oscillator Start-up Timer (OST) is disabled when
EC mode is selected. Therefore, there is no delay in
operation after a Power-on Reset (POR) or wake-up
from Sleep. Because the PIC16F685/687/689/690
design is fully static, stopping the external clock input
will have the effect of halting the device while leaving all
data intact. Upon restarting the external clock, the
device will resume operation as if no time had elapsed.
DS41262A-page 36
Preliminary
EXTERNAL CLOCK (EC)
MODE OPERATION
OSC1/CLKIN
PIC16F685/687/689/690
RA4/AN3/T1G/
OSC2/CLKOUT
I/O (OSC2)
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
3.3.3
FIGURE 3-4:
LP, XT, HS MODES
The LP, XT and HS modes support the use of quartz
crystal resonators or ceramic resonators connected to
the OSC1 and OSC2 pins (Figure 3-3). The mode
selects a low, medium or high gain setting of the
internal inverter-amplifier to support various resonator
types and speed.
LP Oscillator mode selects the lowest gain setting of the
internal inverter-amplifier. LP mode current consumption
is the least of the three modes. This mode is best suited
to drive resonators with a low drive level specification, for
example, tuning fork type crystals.
XT Oscillator mode selects the intermediate gain
setting of the internal inverter-amplifier. XT mode
current consumption is the medium of the three modes.
This mode is best suited to drive resonators with a
medium drive level specification, for example, lowfrequency/AT-cut quartz crystal resonators.
HS Oscillator mode selects the highest gain setting of
the internal inverter-amplifier. HS mode current
consumption is the highest of the three modes. This
mode is best suited for resonators that require a high
drive setting, for example, high-frequency/AT-cut
quartz crystal resonators or ceramic resonators.
CERAMIC RESONATOR
OPERATION
(XT OR HS MODE)
PIC16F685/687/689/690
OSC1
C1
To Internal
Logic
RP(3)
RF(2)
Sleep
OSC2
RS(1)
C2 Ceramic
Resonator
Note 1: A series resistor (RS) may be required for
ceramic resonators with low drive level.
2: The value of RF varies with the Oscillator
mode selected (typically between 2 MΩ to
10 MΩ).
3: An additional parallel feedback resistor (RP)
may be required for proper ceramic resonator
operation (typical value 1 MΩ).
Figure 3-3 and Figure 3-4 show typical circuits for
quartz crystal and ceramic resonators, respectively.
FIGURE 3-3:
QUARTZ CRYSTAL
OPERATION (LP, XT OR
HS MODE)
PIC16F685/687/689/690
OSC1
C1
To Internal
Logic
Quartz
Crystal
OSC2
RF(2)
Sleep
RS(1)
C2
Note 1:
A series resistor (RS) may be required for
quartz crystals with low drive level.
2:
The value of RF varies with the Oscillator
mode selected (typically between 2 MΩ to
10 MΩ).
Note 1: Quartz crystal characteristics vary
according to type, package and
manufacturer. The user should consult the
manufacturer data sheets for specifications
and recommended application.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 37
PIC16F685/687/689/690
3.3.4
EXTERNAL RC MODES
3.4
The External Resistor-Capacitor (RC) modes support
the use of an external RC circuit. This allows the
designer maximum flexibility in frequency choice while
keeping costs to a minimum when clock accuracy is not
required. There are two modes, RC and RCIO.
In RC mode, the RC circuit connects to the OSC1 pin.
The OSC2/CLKOUT pin outputs the RC oscillator
frequency divided by 4. This signal may be used to
provide a clock for external circuitry, synchronization,
calibration, test or other application requirements.
Figure 3-5 shows the RC mode connections.
FIGURE 3-5:
The PIC16F685/687/689/690 has two independent,
internal oscillators that can be configured or selected
as the system clock source.
1.
2.
The HFINTOSC (High-Frequency Internal
Oscillator) is factory calibrated and operates at
8 MHz. The frequency of the HFINTOSC can be
user adjusted ±12% via software using the
OSCTUNE register (Register 3-1).
The LFINTOSC (Low-Frequency Internal
Oscillator) is uncalibrated and operates at
approximately 31 kHz.
The system clock speed can be selected via software
using the Internal Oscillator Frequency Select (IRCF)
bits.
RC MODE
VDD
The system clock can be selected between external or
internal clock sources via the System Clock Selection
(SCS) bit (see Section 3.5 “Clock Switching”).
REXT
Internal
Clock
OSC1
Internal Clock Modes
CEXT
3.4.1
PIC16F685/687/689/690
VSS
FOSC/4
OSC2/CLKOUT
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
CEXT > 20 pF
In RCIO mode, the RC circuit is connected to the OSC1
pin. The OSC2 pin becomes an additional general
purpose I/O pin. The I/O pin becomes bit 4 of PORTA
(RA4). Figure 3-6 shows the RCIO mode connections.
FIGURE 3-6:
RCIO MODE
INTOSC AND INTOSCIO MODES
The INTOSC and INTOSCIO modes configure the
internal oscillators as the system clock source when
the device is programmed using the Oscillator Selection (FOSC) bits in the Configuration Word register
(Register 14-1).
In INTOSC mode, the OSC1 pin is available for general
purpose I/O. The OSC2/CLKOUT pin outputs the
selected internal oscillator frequency divided by 4. The
CLKOUT signal may be used to provide a clock for
external circuitry, synchronization, calibration, test or
other application requirements.
In INTOSCIO mode, the OSC1 and OSC2 pins are
available for general purpose I/O.
VDD
REXT
3.4.2
Internal
Clock
OSC1
CEXT
VSS
PIC16F685/687/689/690
RA4
I/O (OSC2)
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
CEXT > 20 pF
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT)
values and the operating temperature. Other factors
affecting the oscillator frequency are:
• threshold voltage variation
• component tolerances
• packaging variations in capacitance
HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is
a factory calibrated 8 MHz internal clock source. The
frequency of the HFINTOSC can be altered
approximately ±12% via software using the OSCTUNE
register (Register 3-1).
The output of the HFINTOSC connects to a postscaler
and multiplexer (see Figure 3-1). One of seven
frequencies can be selected via software using the
IRCF bits (see Section 3.4.4 “Frequency Select Bits
(IRCF)”).
The HFINTOSC is enabled by selecting any frequency
between 8 MHz and 125 kHz (IRCF ≠ 000) as the
system clock source (SCS = 1), or when Two-Speed
Start-up is enabled (IESO = 1 and IRCF ≠ 000).
The HF Internal Oscillator (HTS) bit (OSCCON<2>)
indicates whether the HFINTOSC is stable or not.
The user also needs to take into account variation due
to tolerance of external RC components used.
DS41262A-page 38
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
3.4.2.1
OSCTUNE Register
The HFINTOSC is factory calibrated but can be
adjusted in software by writing to the OSCTUNE
register (Register 3-1).
The OSCTUNE register has a tuning range of ±12%.
The default value of the OSCTUNE register is ‘0’. The
value is a 5-bit two’s complement number. Due to
process variation, the monotonicity and frequency step
cannot be specified.
REGISTER 3-1:
When the OSCTUNE register is modified, the
HFINTOSC frequency will begin shifting to the new
frequency. The HFINTOSC clock will stabilize within
1 ms. Code execution continues during this shift. There
is no indication that the shift has occurred.
OSCTUNE does not affect the LFINTOSC frequency.
Operation of features that depend on the LFINTOSC
clock source frequency, such as the Power-up Timer
(PWRT), Watchdog Timer (WDT), Fail-Safe Clock
Monitor (FSCM) and peripherals, are not affected by the
change in frequency.
OSCTUNE – OSCILLATOR TUNING RESISTOR (ADDRESS: 90h)
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
—
TUN4
TUN3
TUN2
TUN1
TUN0
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-0
TUN<4:0>: Frequency Tuning bits
01111 = Maximum frequency
01110 =
•
•
•
00001 =
00000 = Oscillator module is running at the calibrated frequency.
11111 =
•
•
•
10000 = Minimum frequency
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 39
PIC16F685/687/689/690
3.4.3
LFINTOSC
3.4.5
The Low-Frequency Internal Oscillator (LFINTOSC) is
an uncalibrated (approximate) 31 kHz internal clock
source.
The output of the LFINTOSC connects to a postscaler
and multiplexer (see Figure 3-1). 31 kHz can be
selected via software using the IRCF bits (see
Section 3.4.4 “Frequency Select Bits (IRCF)”). The
LFINTOSC is also the frequency for the Power-up
Timer (PWRT), Watchdog Timer (WDT) and Fail-Safe
Clock Monitor (FSCM).
The LFINTOSC is enabled by selecting 31 kHz
(IRCF = 000) as the system clock source (SCS = 1), or
when any of the following are enabled:
•
•
•
•
Two-Speed Start-up (IESO = 1 and IRCF = 000)
Power-up Timer (PWRT)
Watchdog Timer (WDT)
Fail-Safe Clock Monitor (FSCM)
3.4.4
1.
2.
3.
5.
FREQUENCY SELECT BITS (IRCF)
The output of the 8 MHz HFINTOSC and 31 kHz
LFINTOSC connects to a postscaler and multiplexer
(see Figure 3-1). The Internal Oscillator Frequency
select bits, IRCF<2:0> (OSCCON<6:4>), select the
frequency output of the internal oscillators. One of eight
frequencies can be selected via software:
•
•
•
•
•
•
•
•
When switching between the LFINTOSC and the
HFINTOSC, the new oscillator may already be shut
down to save power. If this is the case, there is a 10 μs
delay after the IRCF bits are modified before the
frequency selection takes place. The LTS/HTS bits will
reflect the current active status of the LFINTOSC and
the HFINTOSC oscillators. The timing of a frequency
selection is as follows:
4.
The LF Internal Oscillator (LTS) bit (OSCCON<1>)
indicates whether the LFINTOSC is stable or not.
HF AND LF INTOSC CLOCK
SWITCH TIMING
6.
IRCF bits are modified.
If the new clock is shut down, a 10 μs clock startup delay is started.
Clock switch circuitry waits for a falling edge of
the current clock.
CLKOUT is held low and the clock switch
circuitry waits for a rising edge in the new clock.
CLKOUT is now connected with the new clock.
HTS/LTS bits are updated as required.
Clock switch is complete.
If the internal oscillator speed selected is between
8 MHz and 125 kHz, there is no start-up delay before
the new frequency is selected. This is because the old
and the new frequencies are derived from the
HFINTOSC via the postscaler and multiplexer.
8 MHz
4 MHz (Default after Reset)
2 MHz
1 MHz
500 kHz
250 kHz
125 kHz
31 kHz
Note:
Following any Reset, the IRCF bits are set
to ‘110’ and the frequency selection is set
to 4 MHz. The user can modify the IRCF
bits to select a different frequency.
DS41262A-page 40
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
3.5
Clock Switching
The system clock source can be switched between
external and internal clock sources via software using
the System Clock Select (SCS) bit.
3.5.1
SYSTEM CLOCK SELECT (SCS) BIT
The System Clock Select (SCS) bit (OSCCON<0>)
selects the system clock source that is used for the
CPU and peripherals.
• When SCS = 0, the system clock source is
determined by configuration of the FOSC<2:0>
bits in the Configuration Word register (CONFIG).
• When SCS = 1, the system clock source is
chosen by the internal oscillator frequency
selected by the IRCF bits. After a Reset, SCS is
always cleared.
Note:
3.5.2
Any automatic clock switch, which may
occur from Two-Speed Start-up or
Fail-Safe Clock Monitor, does not update
the SCS bit. The user can monitor the
OSTS (OSCCON<3>) to determine the
current system clock source.
OSCILLATOR START-UP TIME-OUT
STATUS BIT
The Oscillator Start-up Time-out Status (OSTS) bit
(OSCCON<3>) indicates whether the system clock is
running from the external clock source, as defined by
the FOSC bits, or from internal clock source. In
particular, OSTS indicates that the Oscillator Start-up
Timer (OST) has timed out for LP, XT or HS modes.
3.6
Two-Speed Clock Start-up Mode
When the PIC16F685/687/689/690 is configured for
LP, XT or HS modes, the Oscillator Start-up Timer
(OST) is enabled (see Section 3.3.1 “Oscillator Startup Timer (OST)”). The OST timer will suspend
program execution until 1024 oscillations are counted.
Two-Speed Start-up mode minimizes the delay in code
execution by operating from the internal oscillator as
the OST is counting. When the OST count reaches
1024 and the OSTS bit (OSCCON<3>) is set, program
execution switches to the external oscillator.
3.6.1
Two-Speed Start-up mode is configured by the
following settings:
• IESO = 1 (CONFIG<10>) Internal/External
Switchover bit.
• SCS = 0.
• FOSC configured for LP, XT or HS mode.
Two-Speed Start-up mode is entered after:
• Power-on Reset (POR) and, if enabled, after
PWRT has expired, or
• Wake-up from Sleep.
If the external clock oscillator is configured to be
anything other than LP, XT or HS mode, then TwoSpeed Start-up is disabled. This is because the external
clock oscillator does not require any stabilization time
after POR or an exit from Sleep.
3.6.2
1.
2.
Two-Speed Start-up mode provides additional power
savings by minimizing the latency between external
oscillator start-up and code execution. In applications
that make heavy use of the Sleep mode, Two-Speed
Start-up will remove the external oscillator start-up
time from the time spent awake and can reduce the
overall power consumption of the device.
3.
4.
This mode allows the application to wake-up from
Sleep, perform a few instructions using the INTOSC
as the clock source and go back to Sleep without
waiting for the primary oscillator to become stable.
7.
Note:
TWO-SPEED START-UP MODE
CONFIGURATION
5.
6.
TWO-SPEED START-UP
SEQUENCE
Wake-up from Power-on Reset or Sleep.
Instructions begin execution by the internal
oscillator at the frequency set in the IRCF bits
(OSCCON<6:4>).
OST enabled to count 1024 clock cycles.
OST timed out, wait for falling edge of the
internal oscillator.
OSTS is set.
System clock held low until the next falling edge
of new clock (LP, XT or HS mode).
System clock is switched to external clock
source.
Executing a SLEEP instruction will abort
the oscillator start-up time and will cause
the OSTS bit (OSCCON<3>) to remain
clear.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 41
PIC16F685/687/689/690
3.6.3
CHECKING EXTERNAL/INTERNAL
CLOCK STATUS
Checking the state of the OSTS bit (OSCCON<3>) will
confirm if the PIC16F685/687/689/690 is running from
the external clock source as defined by the FOSC bits
in the Configuration Word register (CONFIG) or the
internal oscillator.
FIGURE 3-7:
TWO-SPEED START-UP
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
INTOSC
TOST
OSC1
0
1
1022 1023
OSC2
Program Counter
PC
PC + 1
PC + 2
System Clock
DS41262A-page 42
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
3.7
3.7.3
Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) allows the device
to continue operating should the external oscillator fail.
The FSCM can detect oscillator failure anytime after
the Oscillator Start-up Timer (OST) has expired. The
FSCM is enabled by setting the FCMEN bit in the
Configuration Word register (CONFIG). The FSCM is
applicable to all external oscillator modes (LP, XT, HS,
EC, RC and RCIO).
FIGURE 3-8:
FSCM BLOCK DIAGRAM
Clock Monitor
Latch (CM)
(edge-triggered)
Primary
Clock
LFINTOSC
Oscillator
÷ 64
31 kHz
(~32 μs)
488 Hz
(~2 ms)
S
Q
C
Q
The Fail-Safe condition is cleared after a Reset,
executing a SLEEP instruction or toggling the SCS bit
(OSCCON<0>). When the SCS bit is toggled, the OST
is restarted. While the OST is running, the device
continues to operate from the INTOSC selected in
OSCCON. When the OST times out, the Fail-Safe
condition is cleared and the device will be operating
from the external clock source. The Fail-Safe condition
must be cleared before the OSFIF flag can be cleared.
3.7.4
Note:
FAIL-SAFE DETECTION
The FSCM module detects a failed oscillator by
comparing the external oscillator to the FSCM sample
clock. The sample clock is generated by dividing the
LFINTOSC by 64. See Figure 3-8. Inside the fail
detector block is a latch. The external clock sets the
latch on each falling edge of the external clock. The
sample clock clears the latch on each falling edge of
the sample clock. If a sample clock edge occurs while
the latch is cleared, a failure has occurred.
3.7.2
RESET OR WAKE-UP FROM SLEEP
The FSCM is designed to detect an oscillator failure
after the Oscillator Start-up Time (OST) has expired.
The OST is used after waking up from Sleep and after
any type of Reset. The OST is not used with the EC or
RC clock modes so the FSCM will be active as soon as
the Reset or wake-up have completed. When the
FSCM is enabled, the Two-Speed Start-up is also
enabled. Therefore, the device will always be executing
code while the OST is operating.
Clock
Failure
Detected
3.7.1
FAIL-SAFE CONDITION CLEARING
Due to the wide range of oscillator start-up
times, the Fail-Safe circuit is not active
during oscillator start-up (i.e., after exiting
Reset or Sleep). After an appropriate
amount of time, the user should check the
OSTS bit (OSCCON<3>) to verify the
oscillator start-up and system clock
switchover has successfully completed.
FAIL-SAFE OPERATION
When the external clock fails, the FSCM switches the
device clock to an internal clock source and sets the
OSFIF (PIR2<7>) flag. Setting this flag will generate an
interrupt if the OSFIE (PIE2<7>) bit is also set. The
device firmware can then take steps to mitigate the
problems that may arise from a failed clock. The
system clock will continue to be sourced from the
internal clock source until the device firmware
successfully restarts the external oscillator and
switches back to external operation.
The internal clock source chosen by the FSCM is
determined by the IRCF bits (OSCCON<6:4>). This
allows the internal oscillator to be configured before a
failure occurs.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 43
PIC16F685/687/689/690
FIGURE 3-9:
FSCM TIMING DIAGRAM
Sample Clock
Oscillator
Failure
System
Clock
Output
CM Output
(Q)
Failure
Detected
OSCFIF
CM Test
Note:
CM Test
CM Test
The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in
this example have been chosen for clarity.
DS41262A-page 44
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 3-2:
OSCCON – OSCILLATOR CONTROL REGISTER (ADDRESS: 8Fh)
U-0
R/W-1
—
IRCF2
R/W-1
IRCF1
R/W-0
R-1
IRCF0
OSTS
(1)
R-0
R-0
R/W-0
HTS
LTS
SCS
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6-4
IRCF<2:0>: Internal Oscillator Frequency Select bits
000 = 31 kHz
001 = 125 kHz
010 = 250 kHz
011 = 500 kHz
100 = 1 MHz
101 = 2 MHz
110 = 4 MHz (default)
111 = 8 MHz
bit 3
OSTS: Oscillator Start-up Time-out Status bit(1)
1 = Device is running from the external clock defined by FOSC<2:0>
0 = Device is running from the internal oscillator (HFINTOSC or LFINTOSC)
bit 2
HTS: HFINTOSC (High Frequency – 8 MHz to 125 kHz) Status bit
1 = HFINTOSC is stable
0 = HFINTOSC is not stable
bit 1
LTS: LFINTOSC (Low Frequency – 31 kHz) Stable bit
1 = LFINTOSC is stable
0 = LFINTOSC is not stable
bit 0
SCS: System Clock Select bit
1 = Internal oscillator is used for system clock
0 = Clock source defined by FOSC<2:0>
Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator
mode or Fail-Safe mode is enabled.
Legend:
TABLE 3-2:
Address
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
Resets(1)
0Ch
PIR1
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF TMR2IF TMR1IF -000 0000 -000 0000
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE TMR2IE TMR1IE -000 0000 -000 0000
8Fh
OSCCON
—
IRCF2
IRCF1
IRCF0
OSTS
HTS
LTS
SCS
-110 x000 -110 x000
90h
OSCTUNE
—
—
—
TUN4
TUN3
TUN2
TUN1
TUN0
---0 0000 ---u uuuu
2007h(2)
CONFIG
CPD
CP
WDTE
FOSC2
FOSC1
FOSC0
Legend:
Note 1:
2:
MCLRE PWRTE
—
—
x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by oscillators.
Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
See Register 14-1 for operation of all Configuration Word register bits.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 45
PIC16F685/687/689/690
NOTES:
DS41262A-page 46
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.0
I/O PORTS
EXAMPLE 4-1:
There are as many as eighteen general purpose I/O
pins available. Depending on which peripherals are
enabled, some or all of the pins may not be available as
general purpose I/O. In general, when a peripheral is
enabled, the associated pin may not be used as a
general purpose I/O pin.
4.1
PORTA and the TRISA Registers
PORTA is a 6-bit wide, bidirectional port. The
corresponding data direction register is TRISA
(Register 4-2). Setting a TRISA bit (= 1) will make the
corresponding PORTA pin an input (i.e., put the
corresponding output driver in a High-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). The exception is RA3, which
is input only and its TRIS bit will always read as ‘1’.
Example 4-1 shows how to initialize PORTA.
Reading the PORTA register (Register 4-1) reads the
status of the pins, whereas writing to it will write to the
port latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then
written to the port data latch. RA3 reads ‘0’ when
MCLRE = 1.
The TRISA register controls the direction of the
PORTA 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. I/O pins configured as analog input always read
‘0’.
Note:
BCF
BCF
CLRF
BSF
CLRF
BSF
BCF
MOVLW
MOVWF
BCF
4.2
INITIALIZING PORTA
STATUS,RP0
STATUS,RP1
PORTA
STATUS,RP1
ANSEL
STATUS,RP0
STATUS,RP1
0Ch
TRISA
;Bank 0
;
;Init PORTA
;Bank 2
;digital I/O
;Bank 1
;
;Set RA<3:2> as inputs
;and set RA<5:4,1:0>
;as outputs
STATUS,RP0 ;Bank 0
Additional Pin Functions
Every PORTA pin on the PIC16F685/687/689/690 has
an interrupt-on-change option and a weak pull-up
option. RA0 also has an Ultra Low-Power Wake-up
option. The next three sections describe these
functions.
4.2.1
WEAK PULL-UPS
Each of the PORTA pins, except RA3, has an
individually configurable internal weak pull-up. Control
bits WPUAx enable or disable each pull-up. Refer to
Register 4-3. Each weak pull-up is automatically turned
off when the port pin is configured as an output. The
pull-ups are disabled on a Power-on Reset by the
RABPU bit (OPTION_REG<7>). A weak pull-up is
automatically enabled for RA3 when configured as
MCLR and disabled when RA3 is an I/O. There is no
software control of the MCLR pull-up.
The ANSEL (11Eh) register must be
initialized to configure an analog channel
as a digital input. Pins configured as
analog inputs will read ‘0’.
REGISTER 4-1:
PORTA – PORTA REGISTER (ADDRESS: 05h OR 105h)
U-0
U-0
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
—
—
RA5
RA4
RA3
RA2
RA1
RA0
bit 7
bit 0
bit 7-6:
Unimplemented: Read as ‘0’
bit 5-0:
RA<5:0>: PORTA I/O Pin bit
1 = Port pin is > VIH
0 = Port pin is < VIL
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 47
PIC16F685/687/689/690
REGISTER 4-2:
TRISA – PORTA TRI-STATE PORTA REGISTER (ADDRESS: 85h OR 185h)
U-0
U-0
R/W-1
R/W-1
R-1
R/W-1
R/W-1
R/W-1
—
—
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
TRISA<5:0>: PORTA Tri-State Control bit
1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output
Note:
TRISA<5:4> always reads ‘1’ in XT, HS and LP OSC modes.
Legend:
REGISTER 4-3:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
WPUA – WEAK PULL-UP PORTA REGISTER (ADDRESS: 95h)
U-0
U-0
R/W-1
R/W-1
U-0
R/W-1
R/W-1
R/W-1
—
—
WPUA5
WPUA4
—
WPUA2
WPUA1
WPUA0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
WPUA<5:4>: Weak Pull-up Register bit
1 = Pull-up enabled
0 = Pull-up disabled
bit 3
Unimplemented: Read as ‘0’
bit 2-0
WPUA<2:0>: Weak Pull-up Register bit
1 = Pull-up enabled
0 = Pull-up disabled
Note 1: Global RABPU must be enabled for individual pull-ups to be enabled.
2: The weak pull-up device is automatically disabled if the pin is in Output mode
(TRISA = 0).
3: The RA3 pull-up is enabled when configured as MCLR and disabled as an I/O in
the Configuration Word.
4: WPUA<5:4> always reads ‘1’ in XT, HS and LP OSC modes.
Legend:
DS41262A-page 48
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.2.2
INTERRUPT-ON-CHANGE
Each of the PORTA pins is individually configurable as
an interrupt-on-change pin. Control bits IOCAx enable
or disable the interrupt function for each pin. Refer to
Register 4-4. The interrupt-on-change is disabled on a
Power-on Reset.
For enabled interrupt-on-change pins, the values are
compared with the old value latched on the last read of
PORTA. The ‘mismatch’ outputs of the last read are
OR’d together to set the PORTA Change Interrupt Flag
bit (RABIF) in the INTCON register (Register 2-3).
This interrupt can wake the device from Sleep. The
user, in the Interrupt Service Routine, clears the
interrupt by:
a)
Any read or write of PORTA. This will end the
mismatch condition, then,
Clear the flag bit RABIF.
b)
A mismatch condition will continue to set flag bit RABIF.
Reading PORTA will end the mismatch condition and
allow flag bit RABIF to be cleared. The latch holding the
last read value is not affected by a MCLR nor BOR
Reset. After these Resets, the RABIF flag will continue
to be set if a mismatch is present.
Note:
REGISTER 4-4:
If a change on the I/O pin should occur
when the read operation is being executed
(start of the Q2 cycle), then the RABIF
interrupt flag may not get set.
IOCA – INTERRUPT-ON-CHANGE PORTA REGISTER (ADDRESS: 96h)
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
IOCA5
IOCA4
IOCA3
IOCA2
IOCA1
IOCA0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
IOCA<5:0>: Interrupt-on-change PORTA Control bit
1 = Interrupt-on-change enabled
0 = Interrupt-on-change disabled
Note 1: Global Interrupt Enable (GIE) must be enabled for individual interrupts to be
recognized.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 49
PIC16F685/687/689/690
4.2.3
ULTRA LOW-POWER WAKE-UP
The Ultra Low-Power Wake-up (ULPWU) on RA0 allows
a slow falling voltage to generate an interrupt-on-change
on RA0 without excess current consumption. The mode
is selected by setting the ULPWUE bit (PCON<5>). This
enables a small current sink which can be used to
discharge a capacitor on RA0.
To use this feature, the RA0/AN0/C1IN+/ICSPDAT/
ULPWU pin is configured to output ‘1’ to charge the
capacitor, interrupt-on-change for RA0 is enabled, and
RA0 is configured as an input. The ULPWUE bit is set to
begin the discharge and a SLEEP instruction is performed. When the voltage on RA0 drops below VIL, an
interrupt will be generated which will cause the device to
wake-up. Depending on the state of the GIE bit
(INTCON<7>), the device will either jump to the interrupt
vector (0004h) or execute the next instruction when the
interrupt event occurs. See Section 4.2.2 “Interrupton-change” and Section 14.3.3 “PORTA/PORTB
Interrupt” for more information.
This feature provides a low-power technique for
periodically waking up the device from Sleep. The
time-out is dependent on the discharge time of the RC
circuit on RA0. See Example 4-2 for initializing the
Ultra Low-Power Wake-up module.
DS41262A-page 50
The series resistor provides overcurrent protection for
the RA0/AN0/C1IN+/ICSPDAT/ULPWU pin and can
allow for software calibration of the time-out (see
Figure 4-1). A timer can be used to measure the charge
time and discharge time of the capacitor. The charge
time can then be adjusted to provide the desired
interrupt delay. This technique will compensate for the
affects of temperature, voltage and component
accuracy. The Ultra Low-Power Wake-up peripheral
can also be configured as a simple Programmable Low
Voltage Detect or temperature sensor.
Note:
For more information, refer to AN879,
“Using the Microchip Ultra Low-Power
Wake-up Module” Application Note
(DS00879).
EXAMPLE 4-2:
BCF
BCF
BSF
BSF
BCF
BSF
BCF
BCF
CALL
BSF
BSF
BSF
MOVLW
MOVWF
BCF
SLEEP
Preliminary
ULTRA LOW-POWER
WAKE-UP INITIALIZATION
STATUS,RP0
STATUS,RP1
PORTA,0
STATUS,RP1
ANSEL,0
STATUS,RP0
STATUS,RP1
TRISA,0
CapDelay
PCON,ULPWUE
IOCA,0
TRISA,0
B’10001000’
INTCON
STATUS,RP0
;Bank 0
;
;Set RA0 data latch
;BANK 2
;RA0 to digital I/O
;BANK 1
;
;Output high to
;charge capacitor
;Enable ULP Wake-up
;Select RA0 IOC
;RA0 to input
;Enable interrupt
;and clear flag
;BANK 0
;Wait for IOC
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.2.4
PIN DESCRIPTIONS AND
DIAGRAMS
4.2.4.1
Figure 4-2 shows the diagram for this pin. The RA0/
AN0/C1IN+/ICSPDAT/ULPWU pin is configurable
to function as one of the following:
Each PORTA pin is multiplexed with other functions. The
pins and their combined functions are briefly described
here. For specific information about individual functions
such as the comparator or the A/D Converter, refer to the
appropriate section in this data sheet.
FIGURE 4-1:
RA0/AN0/C1IN+/ICSPDAT/ULPWU
•
•
•
•
•
a general purpose I/O
an analog input for the A/D
an analog input to Comparator 1
In-Circuit Serial Programming data
an analog input for the Ultra Low-Power Wake-up
BLOCK DIAGRAM OF RA0
Analog(1)
Input Mode
VDD
Data Bus
D
Q
Weak
CK Q
WR
WPUDA
RABPU
RD
WPUDA
VDD
D
WR
PORTA
Q
I/O Pin
CK Q
VSS
+
D
WR
TRISA
VT
Q
CK Q
IULP
0
RD
TRISA
1
Analog(1)
Input Mode
VSS
ULPWUE
RD
PORTA
D
WR
IOCA
Q
Q
CK Q
D
EN
RD
IOCA
Q
Q3
D
EN
Interrupt-onChange
RD PORTA
To Comparator
To A/D Converter
Note
1:
ANSEL determines Analog Input mode.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 51
PIC16F685/687/689/690
4.2.4.2
RA1/AN1/C12IN-/VREF/ICSPCLK
4.2.4.3
RA2/AN2/T0CKI/INT/C1OUT
Figure 4-2 shows the diagram for this pin. The RA1/
AN1/C12IN-/VREF/ICSPCLK pin is configurable to
function as one of the following:
as one of the following:
•
•
•
•
•
•
•
•
•
•
a general purpose I/O
an analog input for the A/D
an analog input to Comparator 1 or 2
a voltage reference input for the A/D
In-Circuit Serial Programming clock
FIGURE 4-2:
Data Bus
D
WR
WPUA
BLOCK DIAGRAM OF RA1
Q
Analog(1)
Input Mode
Figure 4-3 shows the diagram for this pin. The RA2/
AN2/T0CKI/INT/C1OUT pin is configurable to function
a general purpose I/O
an analog input for the A/D
the clock input for TMR0
an external edge triggered interrupt
a digital output from Comparator 1
FIGURE 4-3:
Data Bus
VDD
CK Q
WR
WPUA
Weak
Q
CK
Analog(1)
Input Mode
VDD
Q
Weak
RABPU
RD
WPUA
RABPU
RD
WPUA
D
BLOCK DIAGRAM OF RA2
C1OUT
Enable
D
WR
PORTA
VDD
Q
D
WR
PORTA
CK Q
VDD
Q
CK
Q
C1OUT
0
I/O Pin
D
WR
TRISA
D
Q
CK Q
VSS
Analog(1)
Input Mode
RD
TRISA
WR
TRISA
I/O Pin
Q
CK
Q
VSS
Analog(1)
Input Mode
RD
TRISA
RD
PORTA
1
RD
PORTA
D
Q
D
Q
CK Q
WR
IOCA
D
EN
RD
IOCA
Q
D
Q3
Q
CK
WR
IOCA
Q
EN
RD
IOCA
Q
EN
Interrupt-onChange
D
Q
Q3
D
EN
Interrupt-onChange
RD PORTA
RD PORTA
To Comparator
To A/D Converter
To TMR0
To INT
Note
1:
ANSEL determines Analog Input mode.
To A/D Converter
Note
DS41262A-page 52
Preliminary
1:
ANSEL determines Analog Input mode.
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.2.4.4
4.2.4.5
RA3/MCLR/VPP
RA4/AN3/T1G/OSC2/CLKOUT
Figure 4-4 shows the diagram for this pin. The RA3/
MCLR/VPP pin is configurable to function as one of
the following:
Figure 4-5 shows the diagram for this pin. The RA4/
AN3/T1G/OSC2/CLKOUT pin is configurable to
function as one of the following:
• a general purpose input
• as Master Clear Reset with weak pull-up
•
•
•
•
•
FIGURE 4-4:
BLOCK DIAGRAM OF RA3
VDD
MCLRE
Data Bus
MCLRE
Reset
RD
TRISA
FIGURE 4-5:
D
CK
Analog(3)
Input Mode
Data Bus
MCLRE
BLOCK DIAGRAM OF RA4
Input
Pin
VSS
RD
PORTA
WR
IOCA
Weak
a general purpose I/O
an analog input for the A/D
a TMR1 gate input
a crystal/resonator connection
a clock output
VSS
WR
WPUA
D
CK
Q
VDD
Q
Weak
Q
Q
Q
EN
RD
IOCA
Interrupt-onChange
Q
RABPU
RD
WPUA
D
CLK(1)
Modes
Oscillator
Circuit
Q3
OSC1
VDD
CLKOUT
Enable
D
D
EN
WR
PORTA
CK
Q
FOSC/4
1
0
I/O Pin
Q
CLKOUT
Enable
RD PORTA
VSS
D
WR
TRISA
CK
Q
Q
INTOSC/
RC/EC(2)
CLKOUT
Enable
RD
TRISA
Analog
Input Mode
RD
PORTA
D
WR
IOCA
CK
Q
Q
D
Q
EN
RD
IOCA
Q
Interrupt-onChange
Q3
D
EN
RD PORTA
To T1G
To A/D Converter
Note 1: CLK modes are XT, HS, LP, LPTMR1 and CLKOUT
Enable.
2: With CLKOUT option.
3: ANSEL determines Analog Input mode.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 53
PIC16F685/687/689/690
4.2.4.6
RA5/T1CKI/OSC1/CLKIN
Figure 4-6 shows the diagram for this pin. The RA5/
T1CKI/OSC1/CLKIN pin is configurable to function
as one of the following:
•
•
•
•
a general purpose I/O
a TMR1 clock input
a crystal/resonator connection
a clock input
FIGURE 4-6:
BLOCK DIAGRAM OF RA5
INTOSC
Mode
Data Bus
WR
WPUA
D
TMR1LPEN(1)
VDD
Q
CK
Weak
Q
RABPU
RD
WPUA
Oscillator
Circuit
OSC2
WR
PORTA
VDD
Q
D
CK
Q
I/O Pin
D
WR
TRISA
Q
CK
Q
VSS
INTOSC
Mode
RD
TRISA
(2)
RD
PORTA
D
WR
IOCA
Q
CK
Q
D
Q
EN
Q3
RD
IOCA
Q
D
EN
Interrupt-onChange
RD PORTA
To TMR1 or CLKGEN
Note
1: Timer1 LP Oscillator enabled.
2: When using Timer1 with LP oscillator, the
Schmitt Trigger is bypassed.
DS41262A-page 54
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 4-1:
Address
Name
05h/105h
PORTA
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
0Bh/8Bh/
INTCON
10Bh/18Bh
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
Resets
—
—
RA5
RA4
RA3
RA2
RA1
RA0
--xx xxxx --uu uuuu
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x 0000 000x
10h
T1CON
T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
14h
SSPCON
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
0000 0000 0000 0000
1Fh
ADCON0
ADFM
VCFG
CHS3
CHS2
CHS1
CHS0
GO/DONE
ADON
0000 0000 0000 0000
TMR1CS
TMR1ON 0000 0000 uuuu uuuu
81h/181h
OPTION_REG
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
1111 1111 1111 1111
85h/185h
TRISA
—
—
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
--11 1111 --11 1111
95h
WPUA
—
—
WPUA5
WPUA4
—
WPUA2
WPUA1
WPUA0
--11 -111 --11 -111
96h
IOCA
—
—
IOCA5
IOCA4
IOCA3
IOCA2
IOCA1
IOCA0
--00 0000 --00 0000
119h
CM1CON0
C1ON
C1OUT
C1OE
C1POL
—
C1R
C1CH1
C1CH0
0000 -000 0000 -000
11Eh
ANSEL
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
1111 1111 1111 1111
Legend:
x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 55
PIC16F685/687/689/690
4.3
PORTB and TRISB Registers
4.4
Additional PORTB Pin Functions
PORTB is a 4-bit wide, bidirectional port. The
corresponding data direction register is TRISB (Register
4-6). Setting a TRISB bit (= 1) will make the
corresponding PORTB pin an input (i.e., put the
corresponding output driver in a High-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). Example 4-3 shows how to
initialize PORTB. Reading the PORTB register (Register
4-5) reads the status of the pins, whereas writing to it will
write to the port latch. All write operations are readmodify-write operations. Therefore, a write to a port
implies that the port pins are read, this value is modified
and then written to the port data latch.
PORTB pins RB<7:4> on the PIC16F685/687/689/690
have an interrupt-on-change option and a weak pull-up
option. The following three sections describe these
PORTB pin functions.
The TRISB register controls the direction of the PORTB
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISB register are
maintained set when using them as analog inputs. I/O
pins configured as analog input always read ‘0’.
Four of the PORTB pins are individually configurable
as an interrupt-on-change pin. Control bits IOCB<7:4>
enable or disable the interrupt function for each pin.
Refer to Register 4-8. The interrupt-on-change feature
is disabled on a Power-on Reset.
EXAMPLE 4-3:
BCF
BCF
CLRF
BSF
MOVLW
MOVWF
BCF
STATUS,RP0
STATUS,RP1
PORTB
STATUS,RP0
FFh
TRISB
STATUS,RP0
4.4.1
Each of the PORTB pins has an individually configurable
internal weak pull-up. Control bits WPUB<7:4> enable or
disable each pull-up. Refer to Register 4-7. Each weak
pull-up is automatically turned off when the port pin is
configured as an output. The pull-ups are disabled on a
Power-on Reset by the RABPU bit (OPTION_REG<7>).
4.4.2
;Bank 0
;
;Init PORTB
;Bank 1
;Set RB<7:4> as inputs
;
;Bank 0
This interrupt can wake the device from Sleep. The user,
in the Interrupt Service Routine, clears the interrupt by:
a)
The ANSELH (11Fh) register must be
initialized to configure an analog channel
as a digital input. Pins configured as
analog inputs will read ‘0’.
Any read or write of PORTB. This will end the
mismatch condition.
Clear the flag bit RABIF.
A mismatch condition will continue to set flag bit RABIF.
Reading or writing PORTB will end the mismatch
condition and allow flag bit RABIF to be cleared. The latch
holding the last read value is not affected by a MCLR nor
Brown-out Reset. After these Resets, the RABIF flag will
continue to be set if a mismatch is present.
Note:
DS41262A-page 56
INTERRUPT-ON-CHANGE
For enabled interrupt-on-change pins, the values are
compared with the old value latched on the last read of
PORTB. The ‘mismatch’ outputs of the last read are
OR’d together to set the PORTB Change Interrupt flag
bit (RABIF) in the INTCON register (Register 2-3).
INITIALIZING PORTB
b)
Note:
WEAK PULL-UPS
Preliminary
If a change on the I/O pin should occur
when the read operation is being executed
(start of the Q2 cycle), then the RABIF
interrupt flag may not get set. Furthermore,
since a read or write on a port affects all bits
of that port, care must be taken when using
multiple pins in Interrupt-on-change mode.
Changes on one pin may not be seen while
servicing changes on another pin.
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 4-5:
PORTB – PORTB REGISTER (ADDRESS: 06h OR 106h)
R/W-x
R/W-x
R/W-x
R/W-x
U-0
U-0
U-0
U-0
RB7
RB6
RB5
RB4
—
—
—
—
bit 7
bit 0
bit 7-4
RB<7:4>: PORTB I/O Pin bits
1 = Port pin is > VIH
0 = Port pin is < VIL
bit 3-0
Unimplemented: Read as ‘0’
Legend:
REGISTER 4-6:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
TRISB – TRI-STATE PORTB REGISTER (ADDRESS: 86h OR 186h)
R/W-1
R/W-1
R/W-1
R/W-1
U-0
U-0
U-0
U-0
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
bit 7
bit 0
bit 7-4
TRISB<7:4>: PORTB Tri-State Control bits
1 = PORTB pin configured as an input (tri-stated)
0 = PORTB pin configured as an output
bit 3-0
Unimplemented: Read as ‘0’
Legend:
REGISTER 4-7:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
WPUB – WEAK PULL-UP PORTB REGISTER (ADDRESS: 115h)
R/W-1
R/W-1
R/W-1
R/W-1
U-0
U-0
U-0
U-0
WPUB7
WPUB6
WPUB5
WPUB4
—
—
—
—
bit 7
bit 0
bit 7-4
WPUB<7:4>: Weak Pull-up Register bits
1 = Pull-up enabled
0 = Pull-up disabled
bit 3-0
Unimplemented: Read as ‘0’
Note 1: Global RABPU must be enabled for individual pull-ups to be enabled.
2: The weak pull-up device is automatically disabled if the pin is in Output mode
(TRISB<7:4> = 0).
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 57
PIC16F685/687/689/690
REGISTER 4-8:
IOCB – INTERRUPT-ON-CHANGE PORTB REGISTER (ADDRESS: 116h)
R/W-0
R/W-0
R/W-0
R/W-0
U-0
U-0
U-0
U-0
IOCB7
IOCB6
IOCB5
IOCB4
—
—
—
—
bit 7
bit 0
bit 7-4
IOCB<7:4>: Interrupt-on-Change bits
1 = Interrupt-on-change enabled
0 = Interrupt-on-change disabled
bit 3-0
Unimplemented: Read as ‘0’
Legend:
DS41262A-page 58
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.4.3
PIN DESCRIPTIONS AND
DIAGRAMS
4.4.3.1
Each PORTB pin is multiplexed with other functions. The
pins and their combined functions are briefly described
here. For specific information about individual functions
such as the SSP, I2C or interrupts, refer to the appropriate
section in this data sheet.
RB4/AN10/SDI/SDA
Figure 4-7 shows the diagram for this pin. The RB4/
AN10/SDI/SDA(1) pin is configurable to function as one
of the following:
•
•
•
•
a general purpose I/O
an analog input for the A/D
a SPI data I/O
an I2C data I/O
Note 1: SDI and SDA are available on
PIC16F687/PIC16F689/PIC16F690 only.
FIGURE 4-7:
Data Bus
WR
WPUB
D
BLOCK DIAGRAM OF RB4
Q
Analog(1)
Input Mode
VDD
CK Q
Weak
RABPU
RD
WPUB
D
WR
PORTB
SSPEN
Q
VDD
0
1
CK Q
1
0
D
WR
TRISB
I/O Pin
Q
CK Q
VSS
Analog(1)
Input Mode
RD
TRISB
RD
PORTB
D
Q
Q
CK Q
WR
IOCB
D
EN
RD
IOCB
Q
Q3
D
ST
EN
Interrupt-onChange
RD PORTB
To SSPSR
To A/D Converter
Available on PIC16F687/PIC16F689/PIC16F690 only.
Note
© 2005 Microchip Technology Inc.
Preliminary
1:
ANSEL determines Analog Input mode.
DS41262A-page 59
PIC16F685/687/689/690
4.4.3.2
RB5/AN11/RX/DT
FIGURE 4-8:
Figure 4-8 shows the diagram for this pin. The RB5/
AN11/RX/DT(1) pin is configurable to function as one
of the following:
D
WR
WPUB
• a general purpose I/O
• an analog input for the A/D
• an asynchronous serial input
•
Data Bus
BLOCK DIAGRAM OF RB5
Q
Analog(1)
Input Mode
VDD
CK Q
Weak
RABPU
RD
WPUB
a synchronous serial data I/O
SYNC
SPEN
Note 1: RX and DT are available on PIC16F687/
PIC16F689/PIC16F690 only.
D
WR
PORTB
Q
CK Q
VDD
EUSART
DT 1
0
1
0
I/O Pin
D
WR
TRISB
Q
CK Q
VSS
Analog(1)
Input Mode
RD
TRISB
RD
PORTB
D
Q
Q
CK Q
WR
IOCB
D
EN
RD
IOCB
Q
Q3
D
ST
EN
Interrupt-onChange
RD PORTB
To EUSART RX/DT
To A/D Converter
Available on PIC16F687/PIC16F689/PIC16F690 only.
Note
DS41262A-page 60
Preliminary
1:
ANSEL determines Analog Input mode.
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.4.3.3
RB6/SCK/SCL
FIGURE 4-9:
Figure 4-9 shows the diagram for this pin. The RB6/
SCK/SCL(1) pin is configurable to function as one of the
following:
• a general purpose I/O
• a SPI™ clock
• an I2C™ clock
Data Bus
WR
WPUB
D
BLOCK DIAGRAM OF RB6
Q
CK Q
D
WR
PORTB
Weak
RABPU
RD
WPUB
Note 1: SCK and SCL are available on
PIC16F687/PIC16F689/PIC16F690 only.
VDD
Q
CK Q
SSPEN
VDD
0
1
0
1
D
WR
TRISB
I/O Pin
Q
CK Q
VSS
RD
TRISB
RD
PORTB
D
WR
IOCB
Q
Q
CK Q
D
EN
RD
IOCB
Q
Q3
D
ST
EN
Interrupt-onChange
RD PORTB
To SSPSR
Available on PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 61
PIC16F685/687/689/690
4.4.3.4
RB7/TX/CK
FIGURE 4-10:
Figure 4-10 shows the diagram for this pin. The RB7/
TX/CK(1) pin is configurable to function as one of the
following:
• a general purpose I/O
• an asynchronous serial output
• a synchronous clock I/O
Data Bus
WR
WPUB
D
BLOCK DIAGRAM OF RB7
Q
VDD
CK Q
Weak
RABPU
RD
WPUB
SPEN
Note 1: TX and CK are available on PIC16F687/
PIC16F689/PIC16F690 only.
TXEN
SYNC
D
WR
PORTB
Q
EUSART
CK 0
1
EUSART
TX
1
0
CK Q
VDD
0
1
0
1
D
WR
TRISB
I/O Pin
Q
CK Q
VSS
RD
TRISB
RD
PORTB
D
WR
IOCB
Q
Q
CK Q
D
EN
RD
IOCB
Q
Q3
D
EN
Interrupt-onChange
RD PORTB
Available on PIC16F687/PIC16F689/PIC16F690 only.
DS41262A-page 62
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 4-2:
Address
Name
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
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
uuuu ----
06h/106h
PORTB
RB7
RB6
RB5
RB4
—
—
—
—
xxxx ----
86h/186h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
0Bh/8Bh/
10Bh/18Bh
INTCON
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
115h
WPUB
WPUB7
WPUB6
WPUB5
WPUB4
—
—
—
—
1111 ----
1111 ----
116h
IOCB
IOCB7
IOCB6
IOCB5
IOCB4
—
—
—
—
0000 ----
0000 ----
Legend:
x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTB.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 63
PIC16F685/687/689/690
4.5
PORTC and TRISC Registers
PORTC is a 8-bit wide, bidirectional port. The
corresponding data direction register is TRISC (Register
4-10). Setting a TRISC bit (= 1) will make the
corresponding PORTC pin an input (i.e., put the
corresponding output driver in a High-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). Example 4-4 shows how to
initialize PORTC. Reading the PORTC register (Register
4-9) reads the status of the pins, whereas writing to it will
write to the port latch. All write operations are readmodify-write operations. Therefore, a write to a port
implies that the port pins are read, this value is modified
and then written to the port data latch.
REGISTER 4-9:
The TRISC register controls the direction of the PORTC
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISC register are
maintained set when using them as analog inputs. I/O
pins configured as analog input always read ‘0’.
Note:
The ANSEL (11Eh) and ANSELH (11Fh)
registers must be initialized to configure
an analog channel as a digital input. Pins
configured as analog inputs will read ‘0’.
EXAMPLE 4-4:
INITIALIZING PORTC
BCF
BCF
CLRF
BSF
CLRF
BSF
BCF
MOVLW
MOVWF
STATUS,RP0
STATUS,RP1
PORTC
STATUS,RP1
ANSEL
STATUS,RP0
STATUS,RP1
0Ch
TRISC
BCF
STATUS,RP0
;Bank 0
;
;Init PORTC
;Bank 2
;digital I/O
;Bank 1
;
;Set RC<3:2> as inputs
;and set RC<5:4,1:0>
;as outputs
;Bank 0
PORTC – PORTC REGISTER (ADDRESS: 07h OR 107h)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
bit 7
bit 7-0
bit 0
RC<7:0>: PORTC General Purpose I/O Pin bits
1 = Port pin is > VIH
0 = Port pin is < VIL
Legend:
REGISTER 4-10:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
TRISC – TRI-STATE PORTC REGISTER (ADDRESS: 87h OR 187h)
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
bit 7
bit 7-0
bit 0
TRISC<7:0>: PORTC Tri-State Control bit
1 = PORTC pin configured as an input (tri-stated)
0 = PORTC pin configured as an output
Legend:
DS41262A-page 64
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.5.1
RC0/AN4/C2IN+
4.5.3
RC2/AN6/P1D
The RC0 is configurable to function as one of the
following:
The RC2/AN6/P1D(1) is configurable to function as
one of the following:
• a general purpose I/O
• an analog input for the A/D
• an analog input to Comparator 2
• a general purpose I/O
• an analog input for the A/D
• a PWM output
4.5.2
RC1/AN5/C12IN-
The RC1 is configurable to function as one of the
following:
• a general purpose I/O
• an analog input for the A/D
• an analog input to Comparator 1 or 2
FIGURE 4-11:
Note 1: P1D is available
PIC16F690 only.
4.5.4
RC3/AN7/P1C
BLOCK DIAGRAM OF RC0
AND RC1
• a general purpose I/O
• an analog input for the A/D
• a PWM output
Note 1: P1C is available
PIC16F690 only.
WR
PORTC
CK
WR
TRISC
CK
FIGURE 4-12:
Q
D
Q
BLOCK DIAGRAM OF RC2
AND RC3
CCPOUT
Enable
VDD
Q
VSS
Analog Input
Mode(1)
WR
PORTC
CK
Q
CCPOUT
0
1
1
0
D
RD
PORTC
To Comparators
To A/D Converter
Note
PIC16F685/
Data Bus
Q
RD
TRISC
on
VDD
Q
I/O Pin
D
PIC16F685/
The RC3/AN7/P1C(1) is configurable to function as one
of the following:
Data Bus
D
on
1:
ANSEL determines Analog Input mode.
WR
TRISC
CK
I/O Pin
Q
Q
VSS
Analog Input
Mode(1)
RD
TRISC
RD
PORTC
To A/D Converter
Available on PIC16F685/PIC16F690 only.
Note
© 2005 Microchip Technology Inc.
Preliminary
1:
ANSEL determines Analog Input mode.
DS41262A-page 65
PIC16F685/687/689/690
4.5.5
RC4/C2OUT/P1B
(1, 2)
The RC4/C2OUT/P1B
as one of the following:
4.5.6
is configurable to function
• a general purpose I/O
• a digital output from Comparator 2
• a PWM output
on
The RC5/CCP1/P1A(1) is configurable to function as
one of the following:
• a general purpose I/O
• a digital input/output for the Enhanced CCP
• a PWM output
Note 1: Enabling both C2OUT and P1B will cause
a conflict on RC4 and create unpredictable
results. Therefore, if C2OUT is enabled,
the ECCP+ can not be used in Half-bridge
or Full-bridge mode and vise-versa.
2: P1B is available
PIC16F690 only.
RC5/CCP1/P1A
PIC16F685/
Note 1: CCP1 and P1A are available
PIC16F685/PIC16F690 only.
FIGURE 4-14:
BLOCK DIAGRAM OF RC4
CCP1OUT
Enable
WR
PORTC
C2OUT EN
CCPOUT EN
WR
TRISC
WR
TRISC
VDD
0
1
Q
CCP1OUT
0
1
I/O Pin
Q
CK Q
CK
I/O Pin
Q
Q
VSS
RD
TRISC
1
0
Data Bus
D
VDD
Q
0
1
CCPOUT EN
CCPOUT
WR
PORTC
CK
D
C2OUT EN
C2OUT
D
BLOCK DIAGRAM OF RC5
Data bus
D
FIGURE 4-13:
on
RD
PORTC
To Enhanced CCP
VSS
Q
Available on PIC16F685/PIC16F690 only.
CK Q
RD
TRISC
RD
PORTC
Available on PIC16F685/PIC16F690 only.
DS41262A-page 66
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
4.5.7
RC6/AN8/SS
The RC6/AN8/SS
of the following:
(1)
4.5.8
is configurable to function as one
RC7/AN9/SDO
The RC7/AN9/SDO(1) is configurable to function as
one of the following:
• a general purpose I/O
• an analog input for the A/D
• a slave select input
Note 1: SS is available on PIC16F687/PIC16F689/
PIC16F690 only.
• a general purpose I/O
• an analog input for the A/D
• a serial data output
Note 1: SDO is available on PIC16F687/
PIC16F689/PIC16F690 only.
FIGURE 4-15:
FIGURE 4-16:
BLOCK DIAGRAM OF RC6
BLOCK DIAGRAM OF RC7
Data Bus
PORT/SDO
Select
D
WR
PORTC
CK
VDD
Q
Data Bus
SDO
Q
D
I/O Pin
D
WR
TRISC
CK
Q
Q
CK
Q
D
WR
TRISC
CK
Q
Q
To SS Input
To A/D Converter
VSS
Analog Input
Mode(1)
RD
TRISC
RD
PORTC
VDD
1
0
I/O Pin
VSS
Analog Input
Mode(1)
RD
TRISC
WR
PORTC
Q
0
1
RD
PORTC
To A/D Converter
Available on PIC16F685/PIC16F690 only.
Note
1:
ANSEL determines Analog Input mode.
Available on PIC16F685/PIC16F690 only.
Note
© 2005 Microchip Technology Inc.
Preliminary
1:
ANSEL determines Analog Input mode.
DS41262A-page 67
PIC16F685/687/689/690
TABLE 4-3:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
Resets
07h/107h
PORTC
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx
uuuu uuuu
14h
SSPCON(1)
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
0000 0000
0000 0000
17h
CCP1CON(2)
P1M1
P1M0
DC1B1
DC1B0
CCP1M3 CCP1M2 CCP1M1 CCP1M0
0000 0000
0000 0000
1Dh
ECCPAS(2)
0000 0000
87h/187h
TRISC
11Ah
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
0000 0000
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111
1111 1111
CM2CON0
C2ON
C2OUT
C2OE
C2POL
—
C2R
C2CH1
C2CH0
0000 -000
0000 -000
11Bh
CM2CON1
MC1OUT
MC2OUT
—
—
—
—
T1GSS
C2SYNC
00-- --10
00-- --10
11Eh
ANSEL
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
1111 1111
1111 1111
—
—
—
ANS11
ANS10
ANS9
ANS8
---- 1111
---- 1111
—
—
STRSYNC
STRD
STRC
STRB
STRA
---0 0001
---0 0001
11Fh
ANSELH
—
19Dh
PSTRCON
—
19Eh
SRCON
SR1
SR0
C1SEN
C2REN
PULSS
PULSR
—
—
0000 00--
0000 00--
118h
VRCON
C1VREN
C2VREN
VRR
VP6EN
VR3
VR2
VR1
VR0
0000 0000
0000 0000
Legend:
Note 1:
2:
x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTC.
PIC16F687/PIC16F689/PIC16F690 only.
PIC16F685/PIC16F690 only.
DS41262A-page 68
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
5.0
TIMER0 MODULE
5.2
A Timer0 interrupt is generated when the TMR0
register timer/counter overflows from FFh to 00h. This
overflow sets the T0IF bit (INTCON<2>). The interrupt
can be masked by clearing the T0IE bit (INTCON<5>).
The T0IF bit must be cleared in software by the Timer0
module Interrupt Service Routine before re-enabling
this interrupt. The Timer0 interrupt cannot wake the
processor from Sleep since the timer is shut off during
Sleep.
The Timer0 module timer/counter has the following
features:
•
•
•
•
•
•
Timer0 Interrupt
8-bit timer/counter
Readable and writable
8-bit software programmable prescaler
Internal or external clock select
Interrupt on overflow from FFh to 00h
Edge select for external clock
Figure 5-1 is a block diagram of the Timer0 module and
the prescaler shared with the WDT.
5.1
Timer0 Operation
Timer mode is selected by clearing the T0CS bit
(OPTION_REG<5>). In Timer mode, the Timer0
module will increment every instruction cycle (without
prescaler). If TMR0 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 the T0CS bit
(OPTION_REG<5>). In this mode, the Timer0 module
will increment either on every rising or falling edge of pin
RA2/AN1/T0CKI/INT/C1OUT. The incrementing edge is
determined by the source edge (T0SE) control bit
(OPTION_REG<4>). Clearing the T0SE bit selects the
rising edge.
FIGURE 5-1:
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
CLKOUT
(= FOSC/4)
Data Bus
0
8
1
Sync 2
cycles
1
T0CKI
pin
TMR0
0
0
T0CS
T0SE
Set Flag bit T0IF
on Overflow
8-bit
Prescaler
PSA
1
8
PSA
WDTE
SWDTEN
PS<2:0>
16-bit
Prescaler
31 kHz
INTOSC
1
WDT
Time-out
0
16
Watchdog
Timer
PSA
WDTPS<3:0>
Note 1:
T0SE, T0CS, PSA, PS<2:0> are bits in the OPTION register, WDTPS<3:0> are bits in the WDTCON register.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 69
PIC16F685/687/689/690
5.3
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
accomplished by sampling the prescaler output on the
Q2 and Q4 cycles of the internal phase clocks.
Therefore, it is necessary for T0CKI to be high for at
least 2 TOSC (and a small RC delay of 20 ns) and low for
at least 2 TOSC (and a small RC delay of 20 ns). Refer
to the electrical specification of the desired device.
Note:
The ANSEL (11Eh) register must be
initialized to configure an analog channel
as a digital input. Pins configured as
analog inputs will read ‘0’.
REGISTER 5-1:
OPTION_REG – OPTION REGISTER (ADDRESS: 81h OR 181h)
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
bit 7
bit 0
bit 7
RABPU: PORTA/PORTB Pull-up Enable bit
1 = PORTA/PORTB pull-ups are disabled
0 = PORTA/PORTB pull-ups are enabled by individual port latch values
bit 6
INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of RA2/AN2/T0CKI/INT/C1OUT pin
0 = Interrupt on falling edge of RA2/AN2/T0CKI/INT/C1OUT pin
bit 5
T0CS: TMR0 Clock Source Select bit
1 = Transition on RA2/AN2/T0CKI/INT/C1OUT pin
0 = Internal instruction cycle clock (CLKOUT)
bit 4
T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on RA2/AN2/T0CKI/INT/C1OUT pin
0 = Increment on low-to-high transition on RA2/AN2/T0CKI/INT/C1OUT 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
PS<2:0>: Prescaler Rate Select bits
BIT VALUE TMR0 RATE WDT RATE(1)
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
Note 1: A dedicated 16-bit WDT postscaler is available. See Section 14.5 “Watchdog
Timer (WDT)” for more information.
Legend:
DS41262A-page 70
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
5.4
EXAMPLE 5-1:
Prescaler
An 8-bit counter is available as a prescaler for the
Timer0 module, or as a postscaler for the Watchdog
Timer. For simplicity, this counter will be referred to as
“prescaler” throughout this data sheet. The prescaler
assignment is controlled in software by the control bit
PSA (OPTION_REG<3>). Clearing the PSA bit will
assign the prescaler to Timer0. Prescale values are
selectable via the PS<2:0> bits (OPTION_REG<2:0>).
The prescaler is not readable or writable. 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.
5.4.1
SWITCHING PRESCALER
ASSIGNMENT
The prescaler assignment is fully under software
control (i.e., it can be changed “on the fly” during
program execution). To avoid an unintended device
Reset, the following instruction sequence (Example 5-1
and Example 5-2) must be executed when changing
the prescaler assignment from Timer0 to WDT.
TABLE 5-1:
Address
CHANGING PRESCALER
(TIMER0 → WDT)
BCF
STATUS,RP0
BCF
STATUS,RP1
CLRWDT
CLRF
TMR0
;Bank 0
;
;Clear WDT
;Clear TMR0 and
;prescaler
;Bank 1
;Required if desired
;PS<2:0> is
;000 or 001
;
;Set postscaler to
;desired WDT rate
;Bank 0
BSF
STATUS,RP0
MOVLW
b’00101111’
MOVWF
OPTION_REG
CLRWDT
MOVLW
MOVWF
BCF
b’00101xxx’
OPTION_REG
STATUS,RP0
To change prescaler from the WDT to the TMR0
module, use the sequence shown in Example 5-2. This
precaution must be taken even if the WDT is disabled.
EXAMPLE 5-2:
CHANGING PRESCALER
(WDT → TIMER0)
CLRWDT
BSF
BCF
MOVLW
STATUS,RP0
STATUS,RP1
b’xxxx0xxx’
MOVWF
BCF
OPTION_REG
STATUS,RP0
;Clear WDT and
;prescaler
;Bank 1
;
;Select TMR0,
;prescale, and
;clock source
;
;Bank 0
REGISTERS ASSOCIATED WITH TIMER0
Name
01h/101h
TMR0
0Bh/8Bh/
10Bh/18Bh
INTCON
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
T0IE
INTE
RABIE
T0IF
INTF
RABIF
Timer0 Module Register
Value on
POR, BOR
Value on
all other
Resets
xxxx xxxx
uuuu uuuu
0000 000x
0000 000x
GIE
PEIE
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
1111 1111
1111 1111
—
—
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
--11 1111
--11 1111
81h/181h
OPTION_REG
85h/185h
TRISA
Legend:
– = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the Timer0 module.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 71
PIC16F685/687/689/690
NOTES:
DS41262A-page 72
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
6.0
TIMER1 MODULE WITH GATE
CONTROL
Figure 6-1 shows the block diagram of the Timer1
module.
The Timer1 Control register (T1CON), shown in
Register 6-1, is used to enable/disable Timer1 and
select the various features of the Timer1 module.
The Timer1 module has the following features:
•
•
•
•
•
•
•
16-bit timer/counter (TMR1H:TMR1L)
Readable and writable
Internal or external clock selection
Synchronous or asynchronous operation
Interrupt on overflow from FFFFh to 0000h
Wake-up upon overflow (Asynchronous mode)
Optional external enable input
- Selectable gate source: T1G or C2 output
(T1GSS)
- Selectable gate polarity (T1GINV)
• Optional LP oscillator
FIGURE 6-1:
TIMER1 BLOCK DIAGRAM
TMR1ON
TMR1GE
T1GINV
TMR1ON
TMR1GE
Set flag bit
TMR1IF on
Overflow
TMR1
TMR1H
To C2 Comparator Module
TMR1 Clock
(1)
Synchronized
clock input
0
TMR1L
1
Oscillator
OSC1/T1CKI
T1SYNC
1
0
OSC2/T1G
1
FOSC/4
Internal
Clock
Synchronize
Prescaler
1, 2, 4, 8
det
0
2
T1CKPS<1:0>
Sleep input
FOSC = 000
FOSC = X00
T1OSCEN
1
T1CKI
0
C2OUT
T1CS
T1OSCEN
*
Note 1:
T1GSS
ST Buffer is low power type when using LP osc, or high speed type when using T1CKI.
Timer1 register increments on rising edge
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 73
PIC16F685/687/689/690
6.1
Timer1 Modes of Operation
6.3
Timer1 can operate in one of three modes:
• 16-bit Timer with prescaler
• 16-bit Synchronous counter
• 16-bit Asynchronous counter
In Timer mode, Timer1 is incremented on every
instruction cycle. In Counter mode, Timer1 is
incremented on the rising edge of the external clock
input T1CKI. In addition, the Counter mode clock can be
synchronized to the microcontroller system clock or run
asynchronously.
In Counter and Timer modules, the counter/timer clock
can be gated by the Timer1 gate, which can be
selected as either the T1G pin or Comparator 2 output.
If an external clock oscillator is needed (and the
microcontroller is using the INTOSC without CLKOUT),
Timer1 can use the LP oscillator as a clock source.
Note:
6.2
In Counter mode, a falling edge must be
registered by the counter prior to the first
incrementing rising edge.
Timer1 has four prescaler options allowing 1, 2, 4 or 8
divisions of the clock input. The T1CKPS bits
(T1CON<5:4>) control the prescale counter. The
prescale counter is not directly readable or writable;
however, the prescaler counter is cleared upon a write to
TMR1H or TMR1L.
6.4
Timer1 Gate
Timer1 gate source is software configurable to be the
T1G pin or the output of Comparator 2. This allows the
device to directly time external events using T1G or
analog events using Comparator 2. See CM2CON1
(Register 8-3) for selecting the Timer1 gate source.
This feature can simplify the software for a Delta-Sigma
A/D converter and many other applications. For more
information on Delta-Sigma A/D converters, see the
Microchip web site (www.microchip.com).
Note:
Timer1 Interrupt
The Timer1 register pair (TMR1H:TMR1L) increments
to FFFFh and rolls over to 0000h. When Timer1 rolls
over, the Timer1 interrupt flag bit (PIR1<0>) is set. To
enable the interrupt on rollover, you must set these bits:
Timer1 Prescaler
TMR1GE bit (T1CON<6>) must be set to
use either T1G or C2OUT as the Timer1
gate source. See Register 8-3 for more
information on selecting the Timer1 gate
source.
Timer1 gate can be inverted using the T1GINV bit
(T1CON<7>), whether it originates from the T1G pin or
Comparator 2 output. This configures Timer1 to
measure either the active-high or active-low time
between events.
• Timer1 interrupt enable bit (PIE1<0>)
• PEIE bit (INTCON<6>)
• GIE bit (INTCON<7>)
The interrupt is cleared by clearing the TMR1IF bit in
the Interrupt Service Routine.
Note:
The TMR1H:TTMR1L register pair and the
TMR1IF bit should be cleared before
enabling interrupts.
FIGURE 6-2:
TIMER1 INCREMENTING EDGE
T1CKI = 1
when TMR1
Enabled
T1CKI = 0
when TMR1
Enabled
Note 1:
2:
Arrows indicate counter increments.
In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of
the clock.
DS41262A-page 74
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 6-1:
T1CON – TIMER1 CONTROL REGISTER (ADDRESS: 10h)
R/W-0
T1GINV
(1)
R/W-0
R/W-0
(2)
TMR1GE
R/W-0
R/W-0
R/W-0
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
R/W-0
R/W-0
TMR1CS TMR1ON
bit 7
bit 0
bit 7
T1GINV: Timer1 Gate Invert bit(1)
1 = Timer1 gate is inverted
0 = Timer1 gate is not inverted
bit 6
TMR1GE: Timer1 Gate Enable bit(2)
If TMR1ON = 0:
This bit is ignored
If TMR1ON = 1:
1 = Timer1 is on if Timer1 gate is not active
0 = Timer1 is on
bit 5-4
T1CKPS<1:0>: 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: LP Oscillator Enable Control bit
If INTOSC without CLKOUT oscillator is active:
1 = LP oscillator is enabled for Timer1 clock
0 = LP oscillator is off
Else:
This bit is ignored
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.
bit 1
TMR1CS: Timer1 Clock Source Select bit
1 = External clock from T1CKI pin (on the rising edge)
0 = Internal clock (FOSC/4)
bit 0
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Note 1: T1GINV bit inverts the Timer1 gate logic, regardless of source.
2: TMR1GE bit must be set to use either T1G pin or C2OUT, as selected by the
T1GSS bit (CM2CON1<1>), as a Timer1 gate source.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 75
PIC16F685/687/689/690
6.5
Timer1 Operation in
Asynchronous Counter Mode
6.6
A crystal oscillator circuit is built-in between pins OSC1
(input) and OSC2 (amplifier output). It is enabled by
setting control bit, T1OSCEN (T1CON<3>). The
oscillator is a low-power oscillator rated up to 32 kHz. It
will continue to run during Sleep. It is primarily intended
for a 32 kHz crystal. Table 3-1 shows the capacitor
selection for the Timer1 oscillator.
If control bit T1SYNC (T1CON<2>) is set, the external
clock input is not synchronized. The timer continues to
increment asynchronous to the internal phase clocks.
The timer will continue to run during Sleep and can
generate an interrupt on overflow, which will wake-up
the processor. However, special precautions in
software are needed to read/write the timer (see
Section 6.5.1 “Reading and Writing Timer1 in
Asynchronous Counter Mode”).
Note:
6.5.1
Timer1 Oscillator
The Timer1 oscillator is shared with the system LP
oscillator. Thus, Timer1 can use this mode only when
the primary system clock is derived from the internal
oscillator. As with the system LP oscillator, the user
must provide a software time delay to ensure proper
oscillator start-up.
The ANSEL (11Eh) register must be
initialized to configure an analog channel
as a digital input. Pins configured as analog
inputs will read ‘0’.
TRISA5 and TRISA4 bits are set when the Timer1
oscillator is enabled. RA5 and RA4 bits read as ‘0’ and
TRISA5 and TRISA4 bits read as ‘1’.
READING AND WRITING TIMER1 IN
ASYNCHRONOUS COUNTER
MODE
Note:
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.
6.7
The oscillator requires a start-up and
stabilization time before use. Thus,
T1OSCEN should be set and a suitable
delay observed prior to enabling Timer1.
Timer1 Operation During Sleep
Timer1 can only operate during Sleep when setup in
Asynchronous Counter mode. In this mode, an external
crystal or clock source can be used to increment the
counter. To set up the timer to wake the device:
For writes, it is recommended that the user simply stop
the timer and write the desired values. A write
contention may occur by writing to the timer registers,
while the register is incrementing. This may produce an
unpredictable value in the timer register.
• Timer1 must be on (T1CON<0>)
• TMR1IE bit (PIE1<0>) must be set
• PEIE bit (INTCON<6>) must be set
The device will wake-up on an overflow. If the GIE bit
(INTCON<7>) is set, the device will wake-up and jump
to the Interrupt Service Routine (0004h) on an overflow.
If the GIE bit is clear, execution will continue with the
next instruction.
TABLE 6-1:
REGISTERS ASSOCIATED WITH TIMER1
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0Bh/8Bh/
INTCON
10Bh/18Bh
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
Addr
0Ch
PIR1
-000 0000
-000 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
TMR1ON 0000 0000
uuuu uuuu
11Bh
CM2CON1 MC1OUT MC2OUT
8Ch
PIE1
Legend:
T1GINV
—
TMR1GE T1CKPS1 T1CKPS0 T1OSCEN
ADIE
T1SYNC
TMR1CS
—
—
—
—
T1GSS
C2SYNC
00-- --10
00-- --10
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
-000 0000
-000 0000
x = unknown, u = unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
DS41262A-page 76
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
7.0
TIMER2 MODULE
7.1
The Timer2 module timer has the following features:
•
•
•
•
•
•
8-bit timer (TMR2 register)
8-bit period register (PR2)
Readable and writable (both registers)
Software programmable prescaler (1:1, 1:4, 1:16)
Software programmable postscaler (1:1 to 1:16)
Interrupt on TMR2 match with PR2
Timer2 has a control register shown in Register 7-1.
TMR2 can be shut-off by clearing control bit, TMR2ON
(T2CON<2>), to minimize power consumption.
Figure 7-1 is a simplified block diagram of the Timer2
module. The prescaler and postscaler selection of
Timer2 are controlled by this register.
Timer2 Operation
Timer2 can be used as the PWM time base for the
PWM mode of the ECCP+ module. The TMR2 register
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
T2CKPS<1:0> (T2CON<1:0>). 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>)).
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 (Power-on Reset, MCLR Reset,
Watchdog Timer Reset, or Brown-out Reset)
TMR2 is not cleared when T2CON is written.
REGISTER 7-1:
T2CON — TIMER2 CONTROL REGISTER (ADDRESS: 12h)
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6-3
TOUTPS<3:0>: Timer2 Output Postscale Select bits
0000 =1:1 postscale
0001 =1:2 postscale
•
•
•
1111 =1:16 postscale
bit 2
TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
bit 1-0
T2CKPS<1:0>: Timer2 Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
1x = Prescaler is 16
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 77
PIC16F685/687/689/690
7.2
Timer2 Interrupt
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.
FIGURE 7-1:
TIMER2 BLOCK DIAGRAM
Sets Flag
bit TMR2IF
TMR2
Output
Prescaler
1:1, 1:4, 1:16
FOSC/4
TMR2
2
Reset
Comparator
EQ
Postscaler
1:1 to 1:16
T2CKPS<1:0>
4
PR2
TOUTPS<3:0>
TABLE 7-1:
Addr
0Bh/8Bh/
10Bh/18Bh
REGISTERS ASSOCIATED WITH TIMER2
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0Ch
PIR1
11h
TMR2
Holding Register for the 8-bit TMR2 Register
Value on
POR, BOR
0000 000x 0000 000x
-000 0000 -000 0000
0000 0000 0000 0000
12h
T2CON
—
8Ch
PIE1
—
92h
PR2
Legend:
x = unknown, u = unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.
DS41262A-page 78
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1
ADIE
RCIE
TXIE
Value on
all other
Resets
SSPIE
Timer2 Module Period Register
CCP1IE
TMR2IE
T2CKPS0 -000 0000 -000 0000
TMR1IE
-000 0000 -000 0000
1111 1111 1111 1111
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
8.0
COMPARATOR MODULE
A complete table showing the output state versus input
conditions and the polarity bit is shown in Table 8-1.
The comparator module has two separate voltage
comparators: Comparator C1 and Comparator C2.
Each comparator offers the following list of features:
•
•
•
•
•
•
•
•
•
•
Control and configuration register
Comparator output available externally
Programmable output polarity
Interrupt-on-change flags
Wake-up from Sleep
Configurable as feedback input to the PWM
Programmable four input multiplexer
Programmable two input reference selections
Timer1 gate
Output synchronization to Timer1 clock input
(Comparator C2 only)
Note:
8.1
TABLE 8-1:
Input Condition
C1POL
C1OUT
C1VN > C1VP
0
0
C1VN < C1VP
0
1
C1VN > C1VP
1
1
C1VN < C1VP
1
0
Note 1: The internal output of the comparator is
latched at the end of each instruction
cycle. External outputs are not latched.
2: The C1 interrupt will operate correctly
with C1OE set or cleared.
C2 can be linked to Timer1Gate.
Control Registers
Both comparators have separate control and
configuration registers: CM1CON0 for C1 and CM2CON0
for C2. In addition, Comparator C2 has a second control
register, CM2CON1, for synchronization control and
simultaneous reading of both comparator outputs.
8.1.1
C1 OUTPUT STATE VS.
INPUT CONDITIONS
3: For C1 output on RA2/AN2/T0CKI/INT/
C1OUT:
C1OE = 1, C1ON = 1 and TRISA<2> = 0.
COMPARATOR C1 CONTROL
REGISTER
The CM1CON0 register (shown in Register 8-1)
contains the control and Status bits for the following:
•
•
•
•
Comparator enable
Comparator input selection
Comparator reference selection
Output mode
Setting C1ON (CM1CON0<7>) enables Comparator
C1 for operation.
Bits C1CH<1:0> (CM1CON0<1:0>) select the
comparator input from the four analog pins AN<7:5,1>.
Note:
To use AN<7:5,1> as analog inputs the
appropriate bits must be programmed to
‘1’ in the ANSEL register.
Setting C1R (CM1CON0<2>) selects the C1VREF
output of the comparator voltage reference module as
the reference voltage for the comparator. Clearing C1R
selects the C1IN+ input on the RA0/AN0/C1IN+/
ICSPDAT/ULPWU pin.
The output of the comparator is available internally via
the C1OUT flag (CM1CON0<6>). To make the output
available for an external connection, the C1OE bit
(CM1CON0<5>) must be set.
The polarity of the comparator output can be inverted
by setting the C1POL bit (CM1CON0<4>). Clearing
C1POL results in a non-inverted output.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 79
PIC16F685/687/689/690
FIGURE 8-1:
COMPARATOR C1 SIMPLIFIED BLOCK DIAGRAM
C1CH<1:0>
C1POL
2
D
RA1/AN1/C12IN-/VREF/ICSPCLK
RC1/AN5/C12IN1-
Q1
0
RC2/AN6/P1D
1
MUX
2
RC3/AN7/P1C
3
Q
EN
To
Data Bus
RD_CM1CON0
Set C1IF
D
Q
Q3*RD_CM1CON0
C1ON(1)
EN
CL
NRESET
C1R
To PWM Logic
C1OE
C1VN
RA0/AN0/C1IN+/ICSPDAT/ULPWU
C1VREF
0
MUX
1
C1OUT
C1VP C1
RA2/AN2/T0CKI/INT/C1OUT(2)
C1POL
Note 1:
2:
DS41262A-page 80
When C1ON = 0, the C1 comparator will produce a ‘0’ output to the XOR Gate.
Output shown for reference only. For more detail see Figure 4-3.
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 8-1:
CM1CON0 – COMPARATOR C1 CONTROL REGISTER 0 (ADDRESS: 119h)
R/W-0
R-0
R/W-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
C1ON
C1OUT
C1OE
C1POL
—
C1R
C1CH1
C1CH0
bit 7
bit 0
bit 7
C1ON: Comparator C1 Enable bit
1 = C1 Comparator is enabled
0 = C1 Comparator is disabled
bit 6
C1OUT: Comparator C1 Output bit
If C1POL = 1 (inverted polarity):
C1OUT = 1, C1VP < C1VN
C1OUT = 0, C1VP > C1VN
If C1POL = 0 (non-inverted polarity):
C1OUT = 1, C1VP > C1VN
C1OUT = 0, C1VP < C1VN
bit 5
C1OE: Comparator C1 Output Enable bit
1 = C1OUT is present on the RA2/AN2/T0CKI/INT/C1OUT pin(1)
0 = C1OUT is internal only
bit 4
C1POL: Comparator C1 Output Polarity Select bit
1 = C1OUT logic is inverted
0 = C1OUT logic is not inverted
bit 3
Unimplemented: Read as ‘0’
bit 2
C1R: Comparator C1 Reference Select bit (non-inverting input)
1 = C1VP connects to C1VREF output
0 = C1VP connects to RA0/AN0/C1IN+/ICSPDAT/ULPWU
bit 1-0
C1CH<1:0>: Comparator C1 Channel Select bit
00 = C1VN of C1 connects to RA1/AN1/C12IN-/VREF/ICSPCLK
01 = C1VN of C1 connects to RC1/AN5/C12IN10 = C1VN of C1 connects to RC2/AN6/P1D
11 = C1VN of C1 connects to RC3/AN7/P1C
Note 1: C1OUT will only drive RA2/AN2/T0CKI/INT/C1OUT if:
C1OE = 1, C1ON = 1 and TRISA<2> = 0.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 81
PIC16F685/687/689/690
8.1.2
COMPARATOR 2 CONTROL
REGISTERS
The comparator output, C2OUT, can be inverted by
setting the C2POL bit (CM2CON0<4>). Clearing
C2POL results in a non-inverted output.
The Comparator 2 (C2) register (CM2CON0) is a
functional copy of the CM1CON0 register described in
Section 8.1.1 “Comparator C1 Control Register”. A
second control register, CM2CON1, is also present for
control of an additional synchronizing feature, as well
as mirrors of both comparator outputs.
8.1.2.1
A complete table showing the output state versus input
conditions and the polarity bit is shown in Table 8-2.
TABLE 8-2:
Comparator 2 Control Register 0
C2 OUTPUT STATE VS. INPUT
CONDITIONS
Input Condition
C2POL
C2OUT
The CM2CON0 register, shown in Register 8-2,
contains the control and Status bits for Comparator C2.
C2VN > C2VP
0
0
C2VN < C2VP
0
1
Setting C2ON (CM2CON0<7>) enables Comparator
C2 for operation.
C2VN > C2VP
1
1
C2VN < C2VP
1
0
Bits C2CH<1:0> (CM2CON0<1:0>) select the comparator input from the four analog pins, AN<7:5,1>.
Note 1: The internal output of the comparator is
latched at the end of each instruction
cycle. External outputs are not latched.
Note 1: To use AN<7:5,1> as analog inputs, the
appropriate bits must be programmed to
1 in the ANSEL register.
2: The C2 interrupt will operate correctly
with C2OE set or cleared. An external
output is not required for the C2 interrupt.
C2R (CM2CON0<2>) selects the reference to be used
with the comparator. Setting C2R (CM2CON0<2>)
selects the C2VREF output of the comparator voltage
reference module as the reference voltage for the
comparator. Clearing C2R selects the C2IN+ input on
the RC0/AN4/C2IN+ pin.
3: For C2 output on RC4/C2OUT/P1B:
C2OE = 1, C2ON = 1 and TRISC<4> = 0.
The output of the comparator is available internally via
the C2OUT bit (CM2CON0<6>). To make the output
available for an external connection, the C2OE bit
(CM2CON0<5>) must be set.
FIGURE 8-2:
COMPARATOR C2 SIMPLIFIED BLOCK DIAGRAM
C2POL
D
Q1
Q
EN
To
Data Bus
RD_CM2CON0
C2CH<1:0>
Set C2IF
2
RA1/AN1/C12IN-/VREF/ICSPCLK
0
RC1/AN5/C12IN-
D
RC2/AN6/P1D
RC3/AN7/P1C
3
C2R
Q3*RD_CM2CON0
EN
CL
NRESET
C2ON(1)
1
MUX C2VN
C2
2
C2VP
C2SYNC
C2POL
C2VREF
Note 1:
2:
DS41262A-page 82
0
MUX
1
Q
Timer1
To PWM Logic
C2OUT
D
RC0/AN4/C2IN+
Q
0
MUX
1
C2OE
RC4/C2OUT/P1B(2)
From TMR1
Clock
When C2ON = 0, the C2 comparator will produce a ‘0’ output to the XOR Gate.
Output shown for reference only. See Figure 4-14 for more detail.
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 8-2:
CM2CON0 – COMPARATOR 2 CONTROL REGISTER 0 (ADDRESS: 11AH)
R/W-0
R-0
R/W-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
C2ON
C2OUT
C2OE
C2POL
—
C2R
C2CH1
C2CH0
bit 7
bit 0
bit 7
C2ON: Comparator C2 Enable bit
1 = C2 Comparator is enabled
0 = C2 Comparator is disabled
bit 6
C2OUT: Comparator C2 Output bit
If C2POL = 1 (inverted polarity):
C2OUT = 1, C2VP < C2VN
C2OUT = 0, C2VP > C2VN
If C2POL = 0 (non-inverted polarity):
C2OUT = 1, C2VP > C2VN
C2OUT = 0, C2VP < C2VN
bit 5
C2OE: Comparator C2 Output Enable bit
1 = C2OUT is present on RC4/C2OUT/P1B(1)
0 = C2OUT is internal only
bit 4
C2POL: Comparator C2 Output Polarity Select bit
1 = C2OUT logic is inverted
0 = C2OUT logic is not inverted
bit 3
Unimplemented: Read as ‘0’
bit 2
C2R: Comparator C2 Reference Select bits (non-inverting input)
1 = C2VP connects to C2VREF
0 = C2VP connects to RC0/AN4/C2IN+
bit 1-0
C2CH<1:0>: Comparator C2 Channel Select bits
00 = C2VN of C2 connects to RA1/AN1/C12IN-/VREF/ICSPCLK
01 = C2VN of C2 connects to RC1/AN5/C12IN10 = C2VN of C2 connects to RC2/AN6/P1D
11 = C2VN of C2 connects to RC3/AN7/P1C
Note 1: C2OUT will only drive RC4/C2OUT/P1B if:
C2OE = 1, C2ON = 1 and TRISC<4> = 0.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 83
PIC16F685/687/689/690
8.1.2.2
Comparator 2 Control Register 1
Comparator 2 has one additional feature: its output can
be synchronized to the Timer1 clock input. Setting
C2SYNC (CM2CON1<0>) synchronizes the output of
Comparator 2 to the falling edge of Timer1’s clock input
(see Figure 8-2 and Register 8-3).
The CM2CON1 register also contains mirror copies of
both comparator outputs, MC1OUT and MC2OUT
(CM2CON1<7:6>). The ability to read both outputs
simultaneously from a single register eliminates the
timing skew of reading separate registers.
Note 1: Obtaining the status of C1OUT or C2OUT
by reading CM2CON1 does not affect the
comparator interrupt mismatch registers.
REGISTER 8-3:
CM2CON1 – COMPARATOR 2 CONTROL REGISTER 1 (ADDRESS: 11Bh)
R-0
R-0
U-0
U-0
U-0
U-0
R/W-1
R/W-0
MC1OUT
MC2OUT
—
—
—
—
T1GSS
C2SYNC
bit 7
bit 0
bit 7
MC1OUT: Mirror Copy of C1OUT bit (CM1CON0<6>)
bit 6
MC2OUT: Mirror Copy of C2OUT bit (CM2CON0<6>)
bit 5-2
Unimplemented: Read as ‘0’
bit 1
T1GSS: Timer1 Gate Source Select bit
1 = Timer1 gate source is RA4/AN3/T1G/OSC2/CLKOUT
0 = Timer1 gate source is C2OUT.
bit 0
C2SYNC: C2 Output Synchronous Mode bit
1 = C2 output is synchronous to falling edge of TMR1 clock
0 = C2 output is asynchronous
Legend:
DS41262A-page 84
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
8.2
8.2.1
Comparator Outputs
The comparator outputs are read through the
CM1CON0, COM2CON0 or CM2CON1 registers.
CM1CON0 and CM2CON0 each contain the individual
comparator output of Comparator 1 and Comparator 2,
respectively. CM2CON1 contains a mirror copy of both
comparator outputs facilitating a simultaneous read of
both comparators. These bits are read-only. The
comparator outputs may also be directly output to the
RA2/AN2/T0CKI/INT/C1OUT and RC4/C2OUT/P1B I/O
pins. When enabled, multiplexers in the output path of
the RA2/AN2/T0CKI/INT/C1OUT and RC4/C2OUT/
P1B pins will switch and the output of each pin will be
the unsynchronized output of the comparator. The
uncertainty of each of the comparators is related to the
input offset voltage and the response time given in the
specifications. Figure 8-1 and Figure 8-2 show the
output block diagrams for Comparators 1 and 2,
respectively.
The TRIS bits will still function as an output enable/
disable for the RA2/AN2/T0CKI/INT/C1OUT and RC4/
C2OUT/P1B pins while in this mode.
The polarity of the comparator outputs can be changed
using the C1POL and C2POL bits (CMxCON0<4>).
Timer1 gate source can be configured to use the T1G
pin or Comparator 2 output as selected by the T1GSS bit
(CM2CON1<1>). The Timer1 gate feature can be used
to time the duration or interval of analog events. The
output of Comparator 2 can also be synchronized with
Timer1 by setting the C2SYNC bit (CM2CON1<0>).
When enabled, the output of Comparator 2 is latched on
the falling edge of Timer1 clock source. If a prescaler is
used with Timer1, Comparator 2 is latched after the
prescaler. To prevent a race condition, the Comparator 2
output is latched on the falling edge of the Timer1 clock
source and Timer1 increments on the rising edge of its
clock source. See the Comparator 2 Block Diagram
(Figure 8-2) and the Timer1 Block Diagram (Figure 6-1)
for more information.
The comparator interrupt flags are set whenever there
is a change in the output value of its respective
comparator. Software will need to maintain information
about the status of the output bits, as read from
CM2CON0<7:6>, to determine the actual change that
has occurred. The CxIF bits, PIR2<6:5>, are the
Comparator Interrupt Flags. Each comparator interrupt
bit must be reset in software by clearing it to ‘0’. Since
it is also possible to write a ‘1’ to this register, a
simulated interrupt may be initiated.
The CxIE bits (PIE2<6:5>) and the PEIE bit
(INTCON<6>) must be set to enable the interrupts. In
addition, the GIE bit must also be set. If any of these
bits are cleared, the interrupt is not enabled, though the
CxIF bits will still be set if an interrupt condition occurs.
The comparator interrupt of the PIC16F685/687/689/
690 differs from previous designs in that the interrupt
flag is set by the mismatch edge and not the mismatch
level. This means that the interrupt flag can be reset
without the additional step of reading or writing the
CMxCON0 register to clear the mismatch registers.
When the mismatch registers are not cleared, an
interrupt will not occur when the comparator output
returns to the previous state. When the mismatch
registers are cleared, an interrupt will occur when the
comparator returns to the previous state.
Note 1: If a change in the CMxCON0 register
(CxOUT) should occur when a read
operation is being executed (start of the
Q2 cycle), then the CxIF (PIR2<5:6>)
interrupt flag may not get set.
It is recommended to synchronize Comparator 2 with
Timer1 by setting the C2SYNC bit when Comparator 2
is used as the Timer1 gate source. This ensures Timer1
does not miss an increment if Comparator 2 changes
during an increment.
© 2005 Microchip Technology Inc.
COMPARATOR INTERRUPT
OPERATION
Preliminary
2: When either comparator is first enabled,
bias circuitry in the comparator module
may cause an invalid output from the
comparator until the bias circuitry is stable. Allow about 1 μs for bias settling then
clear the mismatch condition and interrupt flags before enabling comparator
interrupts.
DS41262A-page 85
PIC16F685/687/689/690
8.3
SR Latch Output
An SR latch is connected to the comparator outputs
C1OUT and C2OUT. Upon any Reset, the SR latch is
always disabled. As a result, the latch output must be
initialized before the outputs are made available to the
output pins. Additionally, the applicable TRIS bits of the
corresponding ports must be set to output (‘0’) and the
respective comparator output enable bits (C1OE and/or
C2OE) must be initialized in order to make the latch
outputs available on the output pins. The four different
configurations available for the SR latch are shown in
Figure 8-5, and the SR<1:0> bits in the SRCON register
(Register 8-4) control whether or not the latch is
enabled. The latch enable state is completely
independent of the enable state for the comparators.
REGISTER 8-4:
The SR latch is a Reset-dominant latch that does not
depend on a clock source. Each of the Set and Reset
inputs are active-high. The Set input is driven by the C1
comparator output following the inversion gate, which
is accounted for with the C1INV bit. If the effective comparator output signal is low, then the latch can be set by
writing ‘1’ to the PULSS bit. Conversely, the Reset input
is driven by the C1 comparator output following the
inversion gate, which is accounted for with the C2INV
bit. If the comparator output signal is low, then the latch
can be reset by writing ‘1’ to the PULSR bit.
SRCON – SR LATCH CONTROL REGISTER (ADDRESS: 19Eh)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
U-0
U-0
(2)
SR0(2)
C1SEN
C2REN
PULSS
PULSR
—
—
SR1
bit 7
bit 0
bit 7-6
SR<1:0>: SR Latch Configuration bits(2)
00 = SR latch is disabled
01 = SR latch is enabled. C1OUT pin is the latch non-inverting output. C2OUT pin is the C2
comparator output.
10 = SR latch is enabled. C1OUT pin is the C1 comparator output. C2OUT pin is the latch
inverting output.
11 = SR latch is enabled. C1OUT pin is the latch non-inverting output. C2OUT pin is the latch
inverting output.
bit 5
C1SEN: C1 Set Enable bit
1 = C1 comparator output sets SR latch
0 = C1 comparator output has no effect on SR latch
bit 4
C2REN: C2 Reset Enable bit
1 = C2 comparator output resets SR latch
0 = C2 comparator output has no effect on SR latch
bit 3
PULSS: Pulse the SET Input of the SR Latch bit
1 = Pulse input
0 = Always reads back ‘0’
bit 2
PULSR: Pulse the Reset Input of the SR Latch bit
1 = Pulse input
0 = Always reads back ‘0’
bit 1-0
Unimplemented: Read as ‘0’.
Note 1: The C1OUT or C2OUT bits in the CM1CON0 and CM2CON0 registers, respectively,
will always reflect the actual comparator outputs (not the pins), regardless the SR
latch operation.
2: To enable the SR Latch output to the pins, the appropriate C1OE, C2OE, TRISA2
and TRISC4 bits (CM1CON0, CM2CON0, TRISA and TRISC registers, respectively) must be properly configured.
Legend:
DS41262A-page 86
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 8-3:
SR LATCH CONFIGURATIONS
SR<1:0> = 00
SR<1:0> = 11
Pulse
Gen
PULSS
C1OUT
S
C1OUT
C1
RC1/AN5/C12IN-
A
RC0/AN4/C2IN+
C2OUT
C2
A
C1
Q
C2
Q
VIN-
C2OUT
VIN+
Pulse
Gen
PULSR
SR<1:0> = 10
SR<1:0> = 01
PULSS
Pulse
Gen
C1OUT
Q
C1
C2
R
PULSR
Pulse
Gen
PULSS
S
Note:
R
RA1/AN1/C12IN-/
VREF/ICSPCLK
RA0/AN0/C1IN+/
ICSPDAT/ULPWU
A
VIN-
A
VIN+
RC1/AN5/C12IN-
A
VIN-
RC0/AN4/C2IN+
A
VIN+
Q
Pulse
Gen
S
C1
Q
C2OUT
C2
R
Q
Pulse
Gen
PULSR
Pulse Generator causes a 1/2 Q-state (1 TOSC) pulse width.
FIGURE 8-4:
SR LATCH SIMPLIFIED BLOCK DIAGRAM
SR<1:0>
2
3
PULSS
C1
S
2
MUX
1
Q
to RA2 port logic
0
C1SEN
C2
R
Q
3
Reset
Dominant(1)
C2REN
2
MUX
1
PULSR
to RC4 port logic
0
SR<1:0>
2
Note 1:
If R = 1 and S = 1 simultaneously, Q = 0, Q = 1
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 87
PIC16F685/687/689/690
8.4
8.4.3
Comparator Reference
The comparator module also allows the selection of an
internally generated voltage reference for one of the
comparator inputs. There are two voltage references
available in the PIC16F685/687/689/690: The voltage
referred to as the comparator reference (CVREF) is a
variable voltage based on VDD; The voltage referred to
as the VP6 reference is a fixed voltage derived from a
stable band gap source. Each source may be
individually routed internally to the comparators. The
VRCON register (Register 8-5) controls the voltage
reference module shown in Figure 8-5.
8.4.1
CONFIGURING THE VOLTAGE
REFERENCE
VP6 REFERENCE
The VP6 reference has a constant voltage output of
0.6V nominal. This reference can be enabled by setting
the VP6EN bit to ‘1’ (VRCON<4>). This reference is
always enabled when the HFINTOSC oscillator is
active.
8.4.4
VP6 STABILIZATION PERIOD
When the voltage reference module is enabled, it will
require some time for the reference and its amplifier
circuits to stabilize. The user program must include a
small delay routine to allow the module to settle. See
the electrical specifications section for the minimum
delay requirement.
The voltage reference can output 32 distinct voltage
levels, 16 in a high range and 16 in a low range.
The following equation determines the output voltages:
EQUATION 8-1:
VOLTAGE REFERENCE
OUTPUT VOLTAGE
VRR = 1 (low range): CVREF = (VR<3:0>/24) X VDD
VRR = 0 (high range):
CVREF = (VDD/4) + (VR<3:0> X VDD/32)
8.4.2
VOLTAGE REFERENCE
ACCURACY/ERROR
The full range of VSS to VDD cannot be realized due to
the construction of the module. The transistors on the top
and bottom of the resistor ladder network (Figure 8-5)
keep CVREF from approaching VSS or VDD. The
exception is when the module is disabled by clearing
C1VREN and C2VREN bits (VRCON<7:6>). When
disabled, the reference voltage is VSS when VR<3:0> is
‘0000’ and the VRR (VRCON<5>) bit is set. This allows
the comparators to detect a zero-crossing and not
consume CVREF module current.
The voltage reference is VDD derived and therefore, the
CVREF output changes with fluctuations in VDD. The
tested absolute accuracy of the comparator voltage
Reference can be found in Section 17.0 “Electrical
Specifications”.
DS41262A-page 88
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 8-5:
VRCON – VOLTAGE REFERENCE CONTROL REGISTER (ADDRESS: 118h)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
C1VREN
C2VREN
VRR
VP6EN
VR3
VR2
VR1
bit 7
R/W-0
VR0
bit 0
bit 7
C1VREN: Comparator 1 Voltage Reference Enable bit
1 = CVREF circuit powered on and routed to C1VREF input of Comparator 1.
0 = 0.6 Volt constant reference routed to C1VREF input of Comparator 1.
bit 6
C2VREN: Comparator 2 Voltage Reference Enable bit
1 = CVREF circuit powered on and routed to C2VREF input of Comparator 2.
0 = 0.6 Volt constant reference routed to C2VREF input of Comparator 2.
bit 5
VRR: Comparator Voltage Reference CVREF Range Selection bit
1 = Low Range
0 = High Range
bit 4
VP6EN: 0.6V Reference Enable bit
1 = enabled
0 = disabled
bit 3-0
VR<3:0>: Comparator Voltage Reference CVREF Value Selection 0 ≤ VR<3:0> ≤ 15
When VRR = 1: CVREF = (VR<3:0>/24) * VDD
When VRR = 0: CVREF = VDD/4 + (VR<3:0>/32) * VDD
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 89
PIC16F685/687/689/690
FIGURE 8-5:
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
16 Stages
8R
R
R
R
R
VDD
8R
VRR
16-1 Analog
MUX
CVREF
VR<3:0>
C1VREN
C1VREF to
Comparator 1
Input
1
0
VP6EN
C2VREN
C2VREF to
Comparator 2
Input
Sleep
HFINTOSC enable
1
0
0.6V
EN
VP6
Reference
A/D Converter
Module
DS41262A-page 90
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
8.5
Comparator Response Time
power consumption while in Sleep mode, turn off the
comparator, CMxCON0<7> = 0, and voltage reference,
VRCON<7:6> = 00.
Response time is the minimum time, after selecting a
new reference voltage or input source, before the
comparator output is ensured to have a valid level. If
the internal reference is changed, the maximum delay
of the internal voltage reference must be considered
when using the comparator outputs. Otherwise, the
maximum delay of the comparators should be used
(Table 17-8).
8.6
While the comparator is enabled during Sleep, an
interrupt will wake-up the device. If the GIE bit
(INTCON<7>) is set, the device will jump to the interrupt
vector (0004h), and if clear, continues execution with the
next instruction. If the device wakes up from Sleep, the
contents of the CM1CON0, CM2CON0 and VRCON
registers are not affected.
Operation During Sleep
8.7
The comparators and voltage reference, if enabled
before entering Sleep mode, remain active during Sleep.
This results in higher Sleep currents than shown in the
power-down specifications. The additional current
consumed by the comparator and the voltage reference
is shown separately in the specifications. To minimize
TABLE 8-3:
Address
Effects of a Reset
A device Reset forces the CM1CON0, CM2CON0 and
VRCON registers to their Reset states. This forces the
comparator module to be in the Comparator Reset
mode, CMxCON0<7> = 0, and the voltage reference to
its OFF state. Thus, all potential inputs are analog
REGISTERS ASSOCIATED WITH COMPARATOR MODULE
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, 105h
PORTA
—
—
RA5
RA4
RA3
RA2
RA1
RA0
--xx xxxx
--uu uuuu
07h, 107h
PORTC
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx
uuuu uuuu
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
0Bh/8Bh/
INTCON
10Bh/18Bh
0Ch
PIR1
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
-000 0000
-000 0000
85h/185h
TRISA
—
—
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
--11 1111
--11 1111
87h/187h
TRISC
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111
1111 1111
118h
VRCON
C1VREN
C2VREN
VRR
VP6EN
VR3
VR2
VR1
VR0
0000 0000
0000 0000
119h
CM1CON0
C1ON
C1OUT
C1OE
C1POL
—
C1R
C1CH1
C1CH0
0000 0000
0000 -000
11Ah
CM2CON0
C2ON
C2OUT
C2OE
C2POL
—
C2R
C2CH1
C2CH0
0000 0000
0000 -000
11Bh
CM2CON1
—
—
—
—
T1GSS
C2SYNC
00-- --10
00-- --10
11Eh
ANSEL
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
1111 1111
1111 1111
19Eh
SRCON
SR1
SR0
C1SEN
C2SEN
PULSS
PULSR
—
—
0000 00--
0000 00--
MC1OUT MC2OUT
Legend: x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Capture, Compare or Timer1 module.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 91
PIC16F685/687/689/690
NOTES:
DS41262A-page 92
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
9.0
ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The analog-to-digital converter (A/D) allows conversion of
an analog input signal to a 10-bit binary representation of
that signal. The PIC16F685/687/689/690 has twelve
analog I/O inputs, plus two internal inputs, multiplexed
into one sample and hold circuit. The output of the sample
and hold is connected to the input of the converter. The
converter generates a binary result via successive
approximation and stores the resulting or remaining 10
bits of data into ADRESL (9Eh) and ADRESH (1Eh). The
voltage reference used in the conversion is software
selectable to either VDD or a voltage applied by the VREF
pin. Figure 9-1 shows the block diagram of the A/D on the
PIC16F685/687/689/690.
FIGURE 9-1:
A/D BLOCK DIAGRAM
VDD
VCFG = 0
VREF
RA0/AN0/C1IN+/ICSPDAT/ULPWU
VCFG = 1
0
RA1/AN1/C12IN-/VREF/ICSPCLK
RA2/AN2/T0CKI/INT/C1OUT
RA4/AN3/T1G/OSC2/CLKOUT
RC0/AN4/C2IN+
RC1/AN5/C12IN1RC2/AN6/P1D(2)
A/D
RC3/AN7/P1C(2)
RC6/AN8/SS(3)
10
GO/DONE
RC7/AN9/SDO(3)
ADFM
RB4/AN10/SDI/SDA(3)
10
ADON(1)
RB5/AN11/RX/DT(3)
ADRESH
CVREF
13
VP6 Reference
ADRESL
VSS
CHS<3:0>
Note 1:
When ADON = 0 all input channels are disconnected from ADC (no loading).
2:
P1C and P1D available on PIC16F685/PIC16F690 only.
3:
SS, SDO, SDA, RX and DT available on PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 93
PIC16F685/687/689/690
9.1
A/D Configuration and Operation
There are four registers available to control the
functionality of the A/D module:
1.
2.
3.
4.
ANSEL (Register 9-1)
ANSELH (Register 9-2)
ADCON0 (Register 9-3)
ADCON1 (Register 9-4)
9.1.1
9.1.2
Analog voltages on any pin that is defined
as a digital input may cause the input
buffer to conduct excess current.
CHANNEL SELECTION
There
are
fourteen
analog
channels
on
PIC16F685/687/689/690.
The
CHS<3:0>
bits
(ADCON0<5:2>) control which channel is connected to
the sample and hold circuit.
TABLE 9-1:
VOLTAGE REFERENCE
There are two options for the voltage reference to the
A/D converter: either VDD is used or an analog voltage
applied to VREF is used. The VCFG bit (ADCON0<6>)
controls the voltage reference selection. If VCFG is set,
then the voltage on the VREF pin is the reference;
otherwise, VDD is the reference.
9.1.4
ANALOG PORT PINS
The
ANS<11:0>
bits
(ANSEL<7:0>
and
ANSELH<3:0>) and the TRISA<4,2:0>, TRISB<5:4>
and TRISC<7:6,3:0>> bits control the operation of the
A/D port pins. Set the corresponding TRISx bits to ‘1’ to
set the pin output driver to its high-impedance state.
Likewise, set the corresponding ANSx bit to disable the
digital input buffer.
Note:
9.1.3
CONVERSION CLOCK
The A/D conversion cycle requires 11 TAD. The source
of the conversion clock is software selectable via the
ADCS bits (ADCON1<6:4>). There are seven possible
clock options:
•
•
•
•
•
•
•
FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/32
FOSC/64
FRC (dedicated internal oscillator)
For correct conversion, the A/D conversion clock
(1/TAD) must be selected to ensure a minimum TAD of
1.6 µs. Table 9-1 shows a few TAD calculations for
selected frequencies.
TAD VS. DEVICE OPERATING FREQUENCIES
A/D Clock Source (TAD)
Device Frequency
Operation
ADCS<2:0>
20 MHz
5 MHz
4 MHz
1.25 MHz
2 TOSC
000
100 ns(2)
400 ns(2)
500 ns(2)
1.6 μs
4 TOSC
100
200
ns(2)
ns(2)
μs(2)
3.2 μs
8 TOSC
001
400 ns(2)
1.6 μs
2.0 μs
6.4 μs
101
ns(2)
3.2 μs
4.0 μs
12.8 μs(3)
16 TOSC
800
800
1.0
μs(3)
25.6 μs(3)
32 TOSC
010
1.6 μs
6.4 μs
64 TOSC
110
3.2 μs
12.8 μs(3)
16.0 μs(3)
51.2 μs(3)
μs(1,4)
μs(1,4)
2-6 μs(1,4)
A/D RC
Legend:
Note 1:
2:
3:
4:
x11
2-6
μs(1,4)
2-6
8.0
2-6
Shaded cells are outside of recommended range.
The A/D RC source has a typical TAD time of 4 μs for VDD > 3.0V.
These values violate the minimum required TAD time.
For faster conversion times, the selection of another clock source is recommended.
When the device frequency is greater than 1 MHz, the A/D RC clock source is only recommended if the
conversion will be performed during Sleep.
DS41262A-page 94
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
9.1.5
STARTING A CONVERSION
A/D
conversion
sample.
Instead,
the
ADRESH:ADRESL registers will retain the value of the
previous conversion. After an aborted conversion, a
2 TAD delay is required before another acquisition can
be initiated. Following the delay, an input acquisition is
automatically started on the selected channel.
The A/D conversion is initiated by setting the
GO/DONE bit (ADCON0<1>). When the conversion is
complete, the A/D module:
• Clears the GO/DONE bit
• Sets the ADIF flag (PIR1<6>)
• Generates an interrupt (if enabled)
Note:
The GO/DONE bit should not be set in the
same instruction that turns on the A/D.
If the conversion must be aborted, the GO/DONE bit
can be cleared in software. The ADRESH:ADRESL
registers will not be updated with the partially complete
FIGURE 9-2:
A/D CONVERSION TAD CYCLES
TCY to TAD TAD1
TAD2
TAD3
TAD4
TAD5
TAD6
TAD7
TAD8
b9
b8
b7
b6
b5
b4
b3
TAD9 TAD10 TAD11
b2
b1
b0
Conversion Starts
Holding Capacitor is Disconnected from Analog Input (typically 100 ns)
Set GO/DONE bit
9.1.6
ADRESH and ADRESL registers are loaded,
GO bit is cleared,
ADIF bit is set,
Holding capacitor is connected to analog input
CONVERSION OUTPUT
The A/D conversion can be supplied in two formats: left
or right justified. The ADFM bit (ADCON0<7>) controls
the output format. Figure 9-3 shows the output formats.
FIGURE 9-3:
10-BIT A/D RESULT FORMAT
ADRESH
(ADFM = 0)
ADRESL
MSB
LSB
bit 7
bit 0
bit 7
10-bit A/D Result
(ADFM = 1)
bit 0
Unimplemented: Read as ‘0’
MSB
bit 7
LSB
bit 0
Unimplemented: Read as ‘0’
© 2005 Microchip Technology Inc.
bit 7
bit 0
10-bit A/D Result
Preliminary
DS41262A-page 95
PIC16F685/687/689/690
REGISTER 9-1:
ANSEL – ANALOG SELECT REGISTER (ADDRESS: 11Eh)
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
bit 7
bit 7-0
bit 0
ANS<7:0>: Analog Select bits
Select between analog or digital function on pins AN<7:0>, respectively.
1 = Analog input. Pin is assigned as analog input.(1)
0 = Digital I/O. Pin is assigned to port or special function.
Note 1: Setting a pin to an analog input automatically disables the digital input circuitry,
weak pull-ups, and interrupt-on-change if available. The corresponding TRIS bit
must be set to Input mode in order to allow external control of the voltage on the pin.
Legend:
REGISTER 9-2:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
ANSELH – ANALOG SELECT HIGH REGISTER (ADDRESS: 11Fh)
U-0
U-0
U-0
U-0
R/W-1
R/W-1
R/W-1
R/W-1
—
—
—
—
ANS11
ANS10
ANS9
ANS8
bit 7
bit 0
bit 7-4
Unimplemented: Read as ‘0’.
bit 3-0
ANS<11:8>: Analog Select bits
Select between analog or digital function on pins AN<11:8>, respectively.
1 = Analog input. Pin is assigned as analog input.(1)
0 = Digital I/O. Pin is assigned to port or special function.
Note 1: Setting a pin to an analog input automatically disables the digital input circuitry,
weak pull-ups, and interrupt-on-change if available. The corresponding TRIS bit
must be set to Input mode in order to allow external control of the voltage on the pin.
Legend:
TABLE 9-2:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
ANALOG SELECT CROSS REFERENCE
I/O Pins
Analog
RB5
Select
Channel
RC7
RC6
RC3
RC2
RC1
RC0
RA4
RA2
RA1
RA0
ANS11 ANS10 ANS9
ANS8
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
AN8
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
AN11
DS41262A-page 96
RB4
AN10
AN9
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 9-3:
ADCON0 – A/D CONTROL REGISTER (ADDRESS: 1Fh)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ADFM
VCFG
CHS3
CHS2
CHS1
CHS0
GO/DONE
ADON
bit 7
bit 0
bit 7
ADFM: A/D Result Formed Select bit
1 = Right justified
0 = Left justified
bit 6
VCFG: Voltage Reference bit
1 = VREF pin
0 = VDD
bit 5-2
CHS<3:0>: Analog Channel Select bits
0000 = Channel 00 (AN0)
0001 = Channel 01 (AN1)
0010 = Channel 02 (AN2)
0011 = Channel 03 (AN3)
0100 = Channel 04 (AN4)
0101 = Channel 05 (AN5)
0110 = Channel 06 (AN6)
0111 = Channel 07 (AN7)
1000 = Channel 08 (AN8)
1001 = Channel 09 (AN9)
1010 = Channel 10 (AN10)
1011 = Channel 11 (AN11)
1100 = CVREF
1101 = VP6
1110 = Reserved. Do not use.
1111 = Reserved. Do not use.
bit 1
GO/DONE: A/D Conversion Status bit
1 = A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle.
This bit is automatically cleared by hardware when the A/D conversion has completed.
0 = A/D conversion completed/not in progress
bit 0
ADON: A/D Enable bit
1 = A/D converter module is enabled
0 = A/D converter is shut off and consumes no operating current
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 97
PIC16F685/687/689/690
REGISTER 9-4:
ADCON1 – A/D CONTROL REGISTER 1 (ADDRESS: 9Fh)
U-0
R/W-0
R/W-0
R/W-0
U-0
U-0
U-0
U-0
—
ADCS2
ADCS1
ADCS0
—
—
—
—
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6-4
ADCS<2:0>: A/D Conversion Clock Select bits
000 = FOSC/2
001 = FOSC/8
010 = FOSC/32
x11 = FRC (clock derived from a dedicated internal oscillator = 500 kHz max)
100 = FOSC/4
101 = FOSC/16
110 = FOSC/64
bit 3-0
Unimplemented: Read as ‘0’
Legend:
DS41262A-page 98
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
9.1.7
CONFIGURING THE A/D
EXAMPLE 9-1:
After the A/D module has been configured as desired,
the selected channel must be acquired before the
conversion is started. The analog input channels must
have their corresponding TRIS bits selected as inputs.
To determine sample time, see Tables 17-16 and 17-17.
After this sample time has elapsed the A/D conversion
can be started.
These steps should be followed for an A/D conversion:
1.
2.
3.
4.
5.
6.
7.
Configure the A/D module:
• Configure analog/digital I/O (ANSx)
• Select A/D conversion clock (ADCON1<6:4>)
• Configure voltage reference (ADCON0<6>)
• Select A/D input channel (ADCON0<5:2>)
• Select result format (ADCON0<7>)
• Turn on A/D module (ADCON0<0>)
Configure A/D interrupt (if desired):
• Clear ADIF bit (PIR1<6>)
• Set ADIE bit (PIE1<6>)
• Set PEIE and GIE bits (INTCON<7:6>)
Wait the required acquisition time.
Start conversion:
• Set GO/DONE bit (ADCON0<1>)
Wait for A/D conversion to complete, by either:
• Polling for the GO/DONE bit to be cleared
(with interrupts disabled); OR
• Waiting for the A/D interrupt
Read A/D Result register pair
(ADRESH:ADRESL), clear bit ADIF if required.
For next conversion, go to step 1 or step 2 as
required. The A/D conversion time per bit is
defined as TAD. A minimum wait of 2 TAD is
required before the next acquisition starts.
© 2005 Microchip Technology Inc.
A/D CONVERSION
;This code block configures the A/D
;for polling, Vdd reference, R/C clock
;and RA0 input.
;
;Conversion start & wait for complete
;polling code included.
;
BSF
STATUS,RP0
;Bank 1
BCF
STATUS,RP1
;
MOVLW B’01110000’
;A/D RC clock
MOVWF ADCON1
;
BSF
TRISA,0
;Set RA0 to input
BCF
STATUS,RP0
;Bank 2
BSF
STATUS,RP1
;
BSF
ANSEL,0
;Set RA0 to analog
BCF
STATUS,RP0
;Bank 0
MOVLW B’10000001’
;Right, Vdd Vref, AN0
MOVWF ADCON0
;
CALL
SampleTime
;Wait min sample time
BSF
ADCON0,GO
;Start conversion
BCF
STATUS,RP1
;
BTFSC ADCON0,GO
;Is conversion done?
GOTO
$-1
;No, test again
MOVF
ADRESH,W
;Read upper 2 bits
MOVWF RESULTHI
;
BSF
STATUS,RP0
;Bank 1
MOVF
ADRESL,W
;Read lower 8 bits
BCF
STATUS,RP0
;Bank 0
MOVWF RESULTLO
Preliminary
DS41262A-page 99
PIC16F685/687/689/690
9.2
A/D Acquisition Requirements
For the A/D converter to meet its specified accuracy, the
charge holding capacitor (CHOLD) must be allowed to
fully charge to the input channel voltage level. The
analog input model is shown in Figure 9-4. The source
impedance (RS) and the internal sampling switch (RSS)
impedance directly affect the time required to charge the
capacitor CHOLD. The sampling switch (RSS) impedance
varies over the device voltage (VDD), see Figure 9-4.
The maximum recommended impedance for analog
sources is 10 kΩ. As the impedance is decreased, the
acquisition time may be decreased. After the analog
input channel is selected (changed), this acquisition
must be done before the conversion can be started.
EQUATION 9-1:
To calculate the minimum acquisition time,
Equation 9-1 may be used. This equation assumes that
1/2 LSb error is used (1024 steps for the A/D). The 1/2
LSb error is the maximum error allowed for the A/D to
meet its specified resolution.
ACQUISITION TIME EXAMPLE
Temperature = 50°C and external impedance of 10k Ω 5.0V V DD
Assumptions:
T ACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
= T AMP + T C + T COFF
= 2µs + T C + [ ( Temperature - 25°C ) ( 0.05µs/°C ) ]
The value for TC can be approximated with the following equations:
1
V AP PLIE D ⎛⎝ 1 – ------------⎞⎠ = V CHOLD
2047
;[1] VCHOLD charged to within 1/2 lsb
–TC
----------⎞
⎛
RC
V AP P LI ED ⎜ 1 – e ⎟ = V CHOLD
⎝
⎠
;[2] VCHOLD charge response to VAPPLIED
– Tc
---------⎞
⎛
1
RC
V AP P LIED ⎜ 1 – e ⎟ = V A P PLIE D ⎛⎝ 1 – ------------⎞⎠
2047
⎝
⎠
;combining [1] and [2]
Solving for TC:
T C = – C HOLD ( R IC + R SS + R S ) ln(1/2047)
= – 10pF ( 1k Ω + 7k Ω + 10k Ω ) ln(0.0004885)
= 1.37 µs
Therefore:
T ACQ = 2µ S + 1.37µ S + [ ( 50°C- 25°C ) ( 0.05µ S /°C ) ]
= 4.67µ S
DS41262A-page 100
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out.
2: The charge holding capacitor (CHOLD) is not discharged after each conversion.
3: The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the pin
leakage specification.
FIGURE 9-4:
ANALOG INPUT MODEL
VDD
Rs
ANx
VA
CPIN
5 pF
VT = 0.6V
VT = 0.6V
RIC ≤ 1k
Sampling
Switch
SS Rss
CHOLD
= DAC capacitance
= 10 pF
I LEAKAGE
± 500 nA
VSS
Legend: CPIN
= Input Capacitance
= Threshold Voltage
VT
I LEAKAGE = Leakage current at the pin due to
various junctions
RIC
= Interconnect Resistance
SS
= Sampling Switch
CHOLD
= Sample/Hold Capacitance (from DAC)
© 2005 Microchip Technology Inc.
Preliminary
6V
5V
VDD 4V
3V
2V
RSS
5 6 7 8 9 10 11
Sampling Switch
(kΩ)
DS41262A-page 101
PIC16F685/687/689/690
9.3
A/D Operation During Sleep
The A/D converter module can operate during Sleep.
This requires the A/D clock source to be set to the FRC
option. When the RC clock source is selected, the A/D
waits one instruction before starting the conversion.
This allows the SLEEP instruction to be executed, thus
eliminating much of the switching noise from the
conversion. When the conversion is complete, the
GO/DONE bit is cleared and the result is loaded into
the ADRESH:ADRESL registers. If the A/D interrupt is
FIGURE 9-5:
enabled, the device awakens from Sleep. If the GIE bit
(INTCON<7>) is set, the program counter is set to the
interrupt vector (0004h). If GIE is clear, the next
instruction is executed. If the A/D interrupt is not
enabled (ADIE and PEIE bits set), the A/D module is
turned off, although the ADON bit remains set.
When the A/D clock source is something other than
RC, a SLEEP instruction causes the present conversion
to be aborted and the A/D module is turned off. The
ADON bit remains set.
A/D TRANSFER FUNCTION
Full-Scale Range
3FFh
3FEh
A/D Output Code
3FDh
3FCh
1 LSB ideal
3FBh
Full-Scale
Transition
004h
003h
002h
001h
000h
Analog Input Voltage
1 LSB ideal
0V
DS41262A-page 102
Zero-Scale
Transition
Preliminary
VREF
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
9.4
Effects of Reset
will be reset to zero. Timer1 is reset to automatically
repeat the A/D acquisition period with minimal software
overhead (moving the ADRESH:ADRESL to the desired
location).
A device Reset forces all registers to their Reset state.
Thus, the A/D module is turned off and any pending
conversion is aborted. The ADRESH:ADRESL
registers are unchanged.
9.5
The appropriate analog input channel must be selected
and the minimum acquisition done before the “special
event trigger” sets the GO/DONE bit (starts a
conversion).
Use of the CCP Trigger
An A/D conversion can be started by the “special event
trigger” of the CCP module. This requires that the
CCP1M<3:0> bits (CCP1CON<3:0>) be programmed
as ‘1011’ and that the A/D module is enabled (ADON bit
is set). When the trigger occurs, the GO/DONE bit will be
set, starting the A/D conversion and the Timer1 counter
TABLE 9-3:
Addr
If the A/D module is not enabled (ADON is cleared), then
the “special event trigger” will be ignored by the A/D
module, but will still reset the Timer1 counter. See
Section 11.0 “Enhanced Capture/Compare/PWM+
(ECCP+) Module” for more information.
SUMMARY OF A/D REGISTERS
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/105h
PORTA
—
—
RA5
RA4
RA3
RA2
RA1
RA0
--xx xxxx --uu uuuu
06h/106h
PORTB
RB7
RB6
RB5
RB4
—
—
—
—
xxxx ---- uuuu ----
07h/107h
PORTC
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx uuuu uuuu
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x 0000 000x
0Bh/8Bh/
INTCON
10Bh/18Bh
0Ch
PIR1
11Eh
ANSEL
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000 -000 0000
ANS7
ANS6
ANS5
ANS4
ANS3
ANS2
ANS1
ANS0
1111 1111 1111 1111
—
—
—
—
ANS11
ANS10
ANS9
ANS8
---- 1111 ---- 1111
11Fh
ANSELH
1Eh
ADRESH A/D Result Register High Byte
1Fh
ADCON0
ADFM
VCFG
CHS3
CHS2
CHS1
CHS0
GO/DONE
ADON
85h/185h
TRISA
—
—
TRISA5
TRISA4
TRISA3
TRISA2
TRISA1
TRISA0
--11 1111 --11 1111
86h/186h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ---- 1111 ----
87h/187h
TRISC
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111 1111 1111
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
9Eh
ADRESL
9Fh
ADCON1
Legend:
xxxx xxxx uuuu uuuu
A/D Result Register Low Byte
—
ADCS2
ADCS1
0000 0000 0000 0000
-000 0000 -000 0000
xxxx xxxx uuuu uuuu
ADCS0
—
—
—
—
-000 ---- -000 ----
x = unknown, u = unchanged, — = unimplemented read as ‘0’. Shaded cells are not used for A/D module.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 103
PIC16F685/687/689/690
NOTES:
DS41262A-page 104
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
10.0
DATA EEPROM AND FLASH
PROGRAM MEMORY
CONTROL
10.1
Data EEPROM memory is readable and writable and
the Flash program memory is readable during normal
operation (full VDD range). These memories are not
directly mapped in the register file space. Instead, they
are indirectly addressed through the Special Function
Registers. There are six SFRs used to access these
memories:
•
•
•
•
•
•
EECON1
EECON2
EEDAT
EEDATH
EEADR
EEADRH
The EEADR and EEADRH registers can address up to
a maximum of 256 bytes of data EEPROM or up to a
maximum of 4K words of program EEPROM.
When selecting a program address value, the MSB of
the address is written to the EEADRH register and the
LSB is written to the EEADR register. When selecting a
data address value, only the LSB of the address is
written to the EEADR register.
10.1.1
EECON1 AND EECON2 REGISTERS
EECON1 is the control register for EE memory
accesses.
When interfacing the data memory block, EEDAT holds
the 8-bit data for read/write, and EEADR holds the
address of the EEDAT location being accessed. This
device has 256 bytes of data EEPROM with an address
range from 0h to 0FFh.
When interfacing the program memory block, the
EEDAT and EEDATH registers form a 2-byte word that
holds the 14-bit data for read/write, and the EEADR
and EEADRH registers form a 2-byte word that holds
the 12-bit address of the EEPROM location being
accessed. This device has 4K words of program
EEPROM with an address range from 0h to 0FFFh.
The program memory allows one-word reads.
The EEPROM data memory allows byte read and write.
A byte write automatically erases the location and
writes the new data (erase before write).
The write time is controlled by an on-chip timer. The
write/erase voltages are generated by an on-chip
charge pump rated to operate over the voltage range of
the device for byte or word operations.
When the device is code-protected, the CPU may
continue to read and write the data EEPROM memory
and read the program memory. When code-protected,
the device programmer can no longer access data or
program memory.
© 2005 Microchip Technology Inc.
EEADR and EEADRH Registers
Control bit EEPGD determines if the access will be a
program or data memory access. When clear, as it is
when reset, any subsequent operations will operate on
the data memory. When set, any subsequent operations
will operate on the program memory. Program memory
can only be read.
Control bits RD and WR initiate read and write,
respectively. These bits cannot be cleared, only set, in
software. They are cleared in hardware at completion
of the read or write operation. The inability to clear the
WR bit in software prevents the accidental, premature
termination of a write operation.
The WREN bit, when set, will allow a write operation to
data EEPROM. On power-up, the WREN bit is clear.
The WRERR bit is set when a write operation is
interrupted by a MCLR or a WDT Time-out Reset
during normal operation. In these situations, following
Reset, the user can check the WRERR bit and rewrite
the location. The data and address will be unchanged
in the EEDAT and EEADR registers.
Interrupt flag bit EEIF (PIR2<4>), is set when write is
complete. It must be cleared in the software.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the data EEPROM write sequence.
Preliminary
DS41262A-page 105
PIC16F685/687/689/690
REGISTER 10-1:
EEDAT – EEPROM DATA REGISTER (ADDRESS: 10Ch)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
EEDAT7
EEDAT6
EEDAT5
EEDAT4
EEDAT3
EEDAT2
EEDAT1
EEDAT0
bit 7
bit 7-0
bit 0
EEDATn: Byte value to Write to or Read from data EEPROM bits
Legend:
REGISTER 10-2:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
EEADR – EEPROM DATA REGISTER (ADDRESS: 10Dh)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
EEDAR7
EEDAR6
EEDAR5
EEDAR4
EEDAR3
EEDAR2
EEDAR1
EEDAR0
bit 7
bit 7-0
bit 0
EEDARn: Byte value to Write to or Read from data EEPROM bits
Legend:
REGISTER 10-3:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
EEDATH – EEPROM DATA HIGH BYTE REGISTER(1) (ADDRESS: 10Eh)
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
EEDATH5
EEDATH4
EEDATH3
EEDATH2
EEDATH1
EEDATH0
bit 7
bit 5-0
bit 0
EEDATH<5:0>: Byte value to Write to or Read from data EEPROM bits or to Read from program memory
Note 1:
PIC16F685/PIC16F689/PIC16F690 only.
Legend:
REGISTER 10-4:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
EEADRH – EEPROM ADDRESS HIGH BYTE REGISTER(1) (ADDRESS: 10Fh)
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
—
—
EEADRH3
EEADRH2
EEADRH1
EEADRH0
bit 7
bit 3-0
bit 0
EEADRH<3:0>: Specifies one of 256 locations for EEPROM Read/Write Operation bits or high bits for
program memory reads
Note 1:
PIC16F685/PIC16F689/PIC16F690 only.
Legend:
DS41262A-page 106
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 10-5:
EECON1 – EEPROM CONTROL REGISTER 1 (ADDRESS: 18Ch)
R/W-x
U-0
U-0
U-0
R/W-x
R/W-0
R/S-0
R/S-0
EEPGD
—
—
—
WRERR
WREN
WR
RD
bit 7
bit 0
bit 7
EEPGD: Program/Data EEPROM Select bit
1 = Accesses program memory
0 = Accesses data memory
bit 6-4
Unimplemented: Read as ‘0’
bit 3
WRERR: EEPROM Error Flag bit
1 = A write operation is prematurely terminated (any MCLR Reset, any WDT Reset during
normal operation or BOR)
0 = The write operation completed
bit 2
WREN: EEPROM Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the data EEPROM
bit 1
WR: Write Control bit
EEPGD = 1:
This bit is ignored
EEPGD = 0:
1 = Initiates a write cycle (The bit is cleared by hardware once write is complete. The WR bit
can only be set, not cleared, in software.)
0 = Write cycle to the data EEPROM is complete
bit 0
RD: Read Control bit
1 = Initiates a memory read (the RD is cleared in hardware and can only be set, not cleared,
in software.)
0 = Does not initiate a memory read
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 107
PIC16F685/687/689/690
10.1.2
READING THE DATA EEPROM
MEMORY
10.1.3
WRITING TO THE DATA EEPROM
MEMORY
To read a data memory location, the user must write the
address to the EEADR register, clear the EEPGD
control bit (EECON1<7>), and then set control bit RD
(EECON1<0>). The data is available in the very next
cycle, in the EEDAT register; therefore, it can be read
in the next instruction. EEDAT will hold this value until
another read or until it is written to by the user (during
a write operation).
To write an EEPROM data location, the user must first
write the address to the EEADR register and the data
to the EEDAT register. Then the user must follow a
specific sequence to initiate the write for each byte.
EXAMPLE 10-1:
Additionally, the WREN bit in EECON1 must be set to
enable write. This mechanism prevents accidental
writes to data EEPROM due to errant (unexpected)
code execution (i.e., lost programs). The user should
keep the WREN bit clear at all times, except when
updating EEPROM. The WREN bit is not cleared
by hardware.
DATA EEPROM READ
BSF
BCF
MOVLW
MOVWF
STATUS, RP1
STATUS, RP0
DATA_EE_ADDR
EEADR
BSF
BCF
STATUS, RP0
EECON1, EEPGD
BCF
BCF
MOVF
BCF
EECON1, RD
STATUS, RP1
EEDAT, W
STATUS, RP0
Required
Sequence
EXAMPLE 10-2:
;Bank 2
;
;
;Data Memory
;Address to read
;Bank 3
;Point to DATA
;memory
;EE Read
;Bank 2
;W = EEDAT
;Bank 0
The write will not initiate if the above sequence is not
followed exactly (write 55h to EECON2, write AAh to
EECON2, then set WR bit) for each byte. Interrupts
should be disabled during this code segment.
After a write sequence has been initiated, clearing the
WREN bit will not affect this write cycle. The WR bit will
be inhibited from being set unless the WREN bit is set.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EE Write Complete
Interrupt Flag bit (EEIF) is set. The user can either
enable this interrupt or poll this bit. EEIF must be
cleared by software.
DATA EEPROM WRITE
BCF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BCF
BSF
STATUS, RP0
STATUS, RP1
DATA_EE_ADDR
EEADR
DATA_EE_DATA
EEDAT
STATUS, RP0
EECON1, EEPGD
EECON1, WREN
;Bank 2
;
;
;Data Memory Address to write
;
;Data Memory Value to write
;Bank 3
;Point to DATA memory
;Enable writes
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
INTCON, GIE
55h
EECON2
AAh
EECON2
EECON1, WR
INTCON, GIE
;Disable INTs.
;
;Write 55h
;
;Write AAh
;Set WR bit to begin write
;Enable INTs.
SLEEP
BCF
BCF
EECON1, WREN
STATUS, RP0
;Wait for interrupt to signal write complete
;Disable writes
;Bank 0
DS41262A-page 108
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
10.1.4
READING THE FLASH PROGRAM
MEMORY
To read a program memory location, the user must
write two bytes of the address to the EEADR and
EEADRH registers, set the EEPGD control bit
(EECON1<7>), and then set control bit RD
(EECON1<0>). Once the read control bit is set, the
program memory Flash controller will use the second
instruction cycle to read the data. This causes the
second instruction immediately following the “BSF
EECON1,RD” instruction to be ignored. The data is
available in the very next cycle, in the EEDAT and
EEDATH registers; therefore, it can be read as two
bytes in the following instructions.
Required
Sequence
EXAMPLE 10-3:
BCF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
BSF
EEDAT and EEDATH registers will hold this value until
another read or until it is written to by the user (during
a write operation).
Note 1: The two instructions following a program
memory read are required to be NOP’s.
This prevents the user from executing a
two-cycle instruction on the next
instruction after the RD bit is set.
2: If the WR bit is set when EEPGD = 1, it
will be immediately reset to ‘0’ and no
operation will take place.
FLASH PROGRAM READ
STATUS, RP0
STATUS, RP1
MS_PROG_EE_ADDR
EEADRH
LS_PROG_EE_ADDR
EEADR
STATUS, RP0
EECON1, EEPGD
EECON1, RD
;Bank 2
;
;
;MS Byte of Program Address to read
;
;LS Byte of Program Address to read
;Bank 3
;Point to PROGRAM memory
;EE Read
;
;First instruction after BSF EECON1,RD executes normally
NOP
NOP
;Any instructions here are ignored as program
;memory is read in second cycle after BSF EECON1,RD
;
BCF
MOVF
MOVF
BCF
STATUS, RP0
EEDAT, W
EEDATH, W
STATUS, RP1
© 2005 Microchip Technology Inc.
;Bank 2
;W = LS Byte of Program EEDAT
;W = MS Byte of Program EEDAT
;Bank 0
Preliminary
DS41262A-page 109
PIC16F685/687/689/690
FIGURE 10-1:
FLASH PROGRAM MEMORY READ CYCLE EXECUTION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
PC
Flash ADDR
Flash Data
PC + 1
INSTR (PC)
INSTR(PC - 1)
executed here
EEADRH,EEADR
INSTR (PC + 1)
BSF EECON1,RD
executed here
PC
+3
PC+3
EEDATH,EEDAT
INSTR(PC + 1)
executed here
PC + 5
PC + 4
INSTR (PC + 3)
Forced NOP
executed here
INSTR (PC + 4)
INSTR(PC + 3)
executed here
INSTR(PC + 4)
executed here
RD bit
EEDATH
EEDAT
Register
EERHLT
DS41262A-page 110
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
10.2
Write Verify
10.4
Depending on the application, good programming
practice may dictate that the value written to the data
EEPROM should be verified (see Example 10-4) to the
desired value to be written.
EXAMPLE 10-4:
WRITE VERIFY
BCF
BSF
MOVF
STATUS, RP0
STATUS, RP1
EEDAT, W
BSF
BSF
STATUS, RP0
EECON1, RD
BCF
XORWF
BTFSS
GOTO
:
BCF
STATUS, RP0
EEDAT, W
STATUS, Z
WRITE_ERR
10.2.1
STATUS, RP1
;Bank 2
;
;EEDAT not changed
;from previous write
;Bank 3
;YES, Read the
;value written
;Bank 2
;
;Is data the same
;No, handle error
;Yes, continue
;Bank 0
Data EEPROM Operation During
Code-Protect
Data memory can be code-protected by programming
the CPD bit in the Configuration Word register
(Register 14-1) to ‘0’.
When the data memory is code-protected, the CPU is
able to read and write data to the data EEPROM. It is
recommended to code-protect the program memory
when code-protecting data memory. This prevents
anyone from programming zeroes over the existing
code (which will execute as NOPs) to reach an added
routine, programmed in unused program memory,
which outputs the contents of data memory.
Programming unused locations in program memory to
‘0’ will also help prevent data memory code protection
from becoming breached.
USING THE DATA EEPROM
The data EEPROM is a high-endurance, byte
addressable array that has been optimized for the
storage of frequently changing information. The
maximum endurance for any EEPROM cell is specified
as D120 and D120A. D120 or D120A specify a
maximum number of writes to any EEPROM location
before a refresh is required of infrequently changing
memory locations.
10.2.2
EEPROM ENDURANCE
A hypothetical data EEPROM is 64 bytes long and has
an endurance of 1M writes. It also has a refresh parameter of 10M writes. If every memory location in the cell
were written the maximum number of times, the data
EEPROM would fail after 64M write cycles. If every
memory location save one were written the maximum
number of times, the data EEPROM would fail after
63M write cycles, but the one remaining location could
fail after 10M cycles. If proper refreshes occurred, then
the lone memory location would have to be refreshed
six times for the data to remain correct.
10.3
Protection Against Spurious Write
There are conditions when the user may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built in. On power-up, WREN is cleared. Also, the
Power-up
Timer
(64 ms
duration)
prevents
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during:
• Brown-out
• Power Glitch
• Software Malfunction
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 111
PIC16F685/687/689/690
TABLE 10-1:
Addr
REGISTERS/BITS ASSOCIATED WITH DATA EEPROM
Name
0Bh/8Bh/
INTCON
10Bh/18Bh
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
0Dh
PIR2
OSFIF
C2IF
C1IF
EEIF
—
—
—
—
0000 ----
0000 ----
8Dh
PIE2
OSFIE
C2IE
C1IE
EEIE
—
—
—
—
0000 ----
0000 ----
10Eh
EEDATH
(1)
—
—
10Fh
EEADRH(1)
—
—
EEDATH5 EEDATH4 EEDATH3 EEDATH2 EEDATH1 EEDATH0
—
—
EEADRH3 EEADRH2 EEADRH1 EEADRH0
--00 0000
--00 0000
---- 0000
---- 0000
10Ch
EEDAT
EEDAT7
EEDAT6
EEDAT5
EEDAT4
EEDAT3
EEDAT2
EEDAT1
EEDAT0
0000 0000
0000 0000
10Dh
EEADR
EEADR7 EEADR6
EEADR5
EEADR4
EEADR3
EEADR2
EEADR1
EEADR0
0000 0000
0000 0000
18Ch
EECON1
EEPGD
—
—
WRERR
WREN
WR
RD
x--- x000
0--- q000
18Dh
EECON2
---- ----
---- ----
Legend:
Note
1:
—
EEPROM Control Register 2 (not a physical register)
x = unknown, u = unchanged, — = unimplemented read as ‘0’, q = value depends upon condition.
Shaded cells are not used by data EEPROM module.
PIC16F685/PIC16F689/PIC16F690 only.
DS41262A-page 112
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.0
ENHANCED
CAPTURE/COMPARE/PWM+
(ECCP+) MODULE
The CCP1CON register controls the operation of
ECCP+. The special event trigger is generated by a
compare match and will clear both TMR1H and TMR1L
registers.
The enhanced Capture/Compare/PWM+ (ECCP+)
module contains a 16-bit register which can operate as
a:
TABLE 11-1:
• 16-bit Capture register
• 16-bit Compare register
• PWM Master/Slave Duty Cycle register
Capture/Compare/PWM Register 1 (CCPR1) is
comprised of two 8-bit registers: CCPR1L (low byte)
and CCPR1H (high byte).
REGISTER 11-1:
ECCP MODE – TIMER
RESOURCES REQUIRED
ECCP Mode
Timer Resource
Capture
Timer1
Compare
Timer1
PWM
Timer2
CCP1CON – ENHANCED CCP OPERATION REGISTER(1) (ADDRESS: 17h)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
bit 7
bit 0
bit 7-6
P1M<1:0>: PWM Output Configuration bits
If CCP1M<3:2> = 00, 01, 10:
xx = P1A assigned as Capture/Compare input; P1B, P1C, P1D assigned as port pins
If CCP1M<3:2> = 11:
00 = Single output; P1A modulated; P1B, P1C, P1D assigned as port pins
01 = Full-bridge output forward; P1D modulated; P1A active; P1B, P1C inactive
10 = Half-bridge output; P1A, P1B modulated with dead band control; P1C, P1D assigned as
port pins
11 = Full-bridge output reverse; P1B modulated; P1C active; P1A, P1D inactive
bit 5-4
DC1B<1:0>: PWM Duty Cycle Least Significant bits
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L.
bit 3-0
CCP1M<3:0>: ECCP Mode Select bits
0000 = Capture/Compare/PWM off (resets ECCP module)
0001 = Unused (reserved)
0010 = Compare mode, toggle output on match (CCP1IF bit is set)
0011 = Unused (reserved)
0100 = Capture mode, every falling edge
0101 = Capture mode, every rising edge
0110 = Capture mode, every 4th rising edge
0111 = Capture mode, every 16th rising edge
1000 = Compare mode, set output on match (CCP1IF bit is set)
1001 = Compare mode, clear output on match (CCP1IF bit is set)
1010 = Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin
is unaffected)
1011 = Compare mode, trigger special event (CCP1IF bit is set; CCP1 resets TMR1or TMR2, and starts
an A/D conversion, if the A/D module is enabled)
1100 = PWM mode; P1A, P1C active-high; P1B, P1D active-high
1101 = PWM mode; P1A, P1C active-high; P1B, P1D active-low
1110 = PWM mode; P1A, P1C active-low; P1B, P1D active-high
1111 = PWM mode; P1A, P1C active-low; P1B, P1D active-low
Note 1:
PIC16F685/PIC16F690 only.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 113
PIC16F685/687/689/690
11.1
Capture Mode
In Capture mode, CCPR1H:CCPR1L captures the
16-bit value of the TMR1 register when an event occurs
on pin RC5/CCP1/P1A. An event is defined as one of
the following and is configured by CCP1CON<3:0>:
•
•
•
•
Every falling edge
Every rising edge
Every 4th rising edge
Every 16th rising edge
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 11-1 shows the
recommended method for switching between capture
prescalers. This example also clears the prescaler
counter and will not generate the “false” interrupt.
EXAMPLE 11-1:
When a capture is made, the interrupt request flag bit,
CCP1IF (PIR1<2>), is set. The interrupt flag must be
cleared in software. If another capture occurs before
the value in register CCPR1 is read, the old captured
value is overwritten by the new captured value.
BCF
BCF
CLRF
MOVLW
CHANGING BETWEEN
CAPTURE PRESCALERS
STATUS, RP0
STATUS, RP1
CCP1CON
NEW_CAPT_PS
;Bank 0
;
;Turn ECCP module off
;Load the W reg with
;the new prescaler
;move value and ECCP ON
;Load CCP1CON with this
;value
MOVWF CCP1CON
11.1.1
CCP1 PIN CONFIGURATION
In Capture mode, the RC5/CCP1/P1A pin should be
configured as an input by setting the TRISC<5> bit.
Note:
If the RC5/CCP1/P1A pin is configured as
an output, a write to the port can cause a
capture condition.
FIGURE 11-1:
Prescaler
÷ 1, 4, 16
CAPTURE MODE
OPERATION BLOCK
DIAGRAM
CCPR1H
and
Edge Detect
CCPR1L
In Compare mode, the 16-bit CCPR1 register value is
constantly compared against the TMR1 register pair
value. When a match occurs, the RC5/CCP1/P1A pin
is:
The action on the pin is based on the value of control
bits, CCP1M<3:0> (CCP1CON<3:0>). At the same
time, interrupt flag bit, CCP1IF (PIR1<2>), is set.
FIGURE 11-2:
Capture
Enable
TMR1H
Compare Mode
• Driven high
• Driven low
• Remains unchanged
Set Flag bit CCP1IF
(PIR1<2>)
RC5/CCP1/P1A
pin
11.2
COMPARE MODE
OPERATION BLOCK
DIAGRAM
TMR1L
CCP1CON<3:0>
CCP1CON<3:0>
Mode Select
Q’s
11.1.2
Timer1 must be running in Timer mode or Synchronized
Counter mode for the ECCP module to use the capture
feature. In Asynchronous Counter mode, the capture
operation may not work.
11.1.3
RC5/CCP1/P1A
pin
CCPR1H CCPR1L
Q
S
R
Output
Logic
Match
Comparator
TMR1H
TRISC<5>
Output Enable
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 (PIR1<2>) following
any such change in operating mode.
11.1.4
Set Flag bit CCP1IF
(PIR1<2>)
TIMER1 MODE SELECTION
TMR1L
Special Event Trigger
Special Event Trigger will:
• clear TMR1H and TMR1L registers
• NOT set interrupt flag bit TMR1IF (PIR1<0>)
• set the GO/DONE bit (ADCON0<1>)
ECCP PRESCALER
There are four prescaler settings specified by bits
CCP1M<3:0> (CCP1CON<3:0>). Whenever the ECCP
module is turned off, or the ECCP module is not in
Capture mode, the prescaler counter is cleared. Any
Reset will clear the prescaler counter.
DS41262A-page 114
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.2.1
CCP1 PIN CONFIGURATION
11.2.4
The user must configure the RC5/CCP1/P1A pin as an
output by clearing the TRISC<5> bit.
Note:
Clearing the CCP1CON register will force
the RC5/CCP1/P1A compare output latch
to the default low level. This is not the
PORTC I/O data latch.
11.2.2
TIMER1 MODE SELECTION
Timer1 must be running in Timer mode or Synchronized
Counter mode if the ECCP module is using the
compare feature. In Asynchronous Counter mode, the
compare operation may not work.
11.2.3
In this mode (CCP1M<3:0> = 1011), an internal
hardware trigger is generated, which may be used to
initiate an action. See Register 11-1.
The special event trigger output of the CCP occurs
immediately upon a match between the TMR1H,
TMR1L register pair and CCPR1H, CCPR1L register
pair. The TMR1H, TMR1L register pair is not reset until
the next rising edge of the TMR1 clock. This allows the
CCPR1H, CCPR1L register pair to effectively provide a
16-bit programmable period register for Timer1. The
special event trigger output also starts an A/D
conversion provided that the A/D module is enabled.
Note 1: The special event trigger from the CCP
module will not set interrupt flag bit
TMR1IF (PIR1<0>).
SOFTWARE INTERRUPT MODE
When Generate Software Interrupt mode is chosen
(CCP1M<3:0> = 1010), the CCP1 pin is not affected.
The CCP1IF (PIR1<2>) bit is set, causing a ECCP
interrupt (if enabled). See Register 11-1.
TABLE 11-2:
SPECIAL EVENT TRIGGER
2: Removing the match condition by
changing the contents of the CCPR1H
and CCPR1L register pair between the
clock edge that generates the special
event trigger and the clock edge that
generates the TMR1 Reset, will preclude
the Reset from occurring.
REGISTERS ASSOCIATED WITH CAPTURE, COMPARE AND TIMER1(1)
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0Bh/8Bh/
INTCON
10Bh/18Bh
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
Addr
0Ch
PIR1
-000 0000
-000 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
0000 0000
uuuu uuuu
11Bh
CM2CON1
MC1OUT MC2OUT
00-- --10
00-- --10
15h
CCPR1L
Capture/Compare/PWM Register 1 Low Byte
xxxx xxxx
uuuu uuuu
16h
CCPR1H
Capture/Compare/PWM Register 1 High Byte
xxxx xxxx
uuuu uuuu
17h
CCP1CON
87h/187h
TRISC
8Ch
PIE1
Legend:
Note
T1GINV
TMR1GE T1CKPS1 T1CKPS0 T1OSCEN
—
—
—
T1SYNC
—
TMR1CS TMR1ON
T1GSS
C2SYNC
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
0000 0000
0000 0000
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111
1111 1111
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
-000 0000
-000 0000
– = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the Capture, Compare or Timer1
module.
1:
PIC16F685/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 115
PIC16F685/687/689/690
11.3
Enhanced PWM Mode
Figure 11-3 shows a simplified block diagram of PWM
operation.
The Enhanced CCP module produces up to a 10-bit
resolution PWM output and may have up to four outputs,
depending on the selected operating mode. These
outputs, designated P1A through P1D, are multiplexed
with I/O pins on PORTC. The pin assignments are
summarized in Table 11-3.
FIGURE 11-3:
To configure I/O pins as PWM outputs, the proper PWM
mode must be selected by setting the P1M<1:0> and
CCP1M<3:0> bits (CCP1CON<7:6> and CCP1CON
<3:0>, respectively). The appropriate TRISC bits must
also be set as outputs.
SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODULE
CCP1CON<5:4>
Duty Cycle Registers
CCP1M<3:0>
4
P1M<1:0>
2
CCPR1L
CCP1/P1A
RC5/CCP1/P1A
TRISC<5>
CCPR1H (Slave)
P1B
R
Comparator
TRISC<4>
Output
Controller
Q
RC4/C2OUT/P1B
RC3/AN7/P1C
P1C
(1)
TMR2
TRISC<3>
S
P1D
Comparator
Clear Timer2,
toggle PWM pin and
latch duty cycle
PR2
Note
11.3.1
1:
TRISC<2>
PWM1CON
The 8-bit timer TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit
time base.
PWM OUTPUT CONFIGURATIONS
The P1M<1:0> bits in the CCP1CON register allows
one of four configurations:
•
•
•
•
The general relationship of the outputs in all
configurations is summarized in Figure 11-3.
Note:
Single Output
Half-bridge Output
Full-bridge Output, Forward mode
Full-bridge Output, Reverse mode
TABLE 11-3:
RC2/AN6/P1D
Clearing the CCP1CON register will force
the PWM output latches to their default
inactive levels. This is not the PORTC I/O
data latch.
PIN ASSIGNMENTS FOR VARIOUS ENHANCED CCP MODES
ECCP Mode
CCP1CON
Configuration
RC5
RC4
RC3
RC2
Compatible CCP
00xx11xx
CCP1
RC4/C2OUT
RC3/AN7
RC2/AN6
Dual PWM
10xx11xx
P1A
P1B
RC3/AN7
RC2/AN6
Quad PWM
x1xx11xx
P1A
P1B
P1C
P1D
Legend: x = Don’t care. Shaded cells indicate pin assignments not used by ECCP in a given mode.
Note 1: TRIS register values must be configured appropriately.
2: With ECCP in Dual or Quad PWM mode, the C2OUT output control of PORTC must be disabled.
DS41262A-page 116
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.3.2
PWM PERIOD
A PWM output (Figure 11-4 and Figure 11-5) has a time
base (period) and a time that the output is active (duty
cycle). The PWM period is specified by writing to the
PR2 register. The PWM period can be calculated using
the following formula:
The following equation is used to calculate the PWM
duty cycle in time:
EQUATION 11-2:
PWM DUTY CYCLE TIME
PWM duty cycle = ( CCPR1L:CCP1CON<5:4> ) •
T OSC • (TMR2 prescale value)
EQUATION 11-1:
PWM PERIOD (TIME BASE)
When the CCPR1H and 2-bit latch match TMR2,
concatenated with an internal 2-bit Q clock or 2 bits of
the TMR2 prescaler, the appropriate PWM pin is
toggled. In Dual PWM mode, the pin will be toggled
after the dead band time has expired.
PWM period = [ ( PR2 ) + 1 ] • 4 • T OSC •
(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 appropriate PWM pin toggles. In Dual PWM
mode, this occurs after the dead band delay
expires (exception: if PWM duty cycle = 0%, the
pin will not be set)
• The PWM duty cycle is latched from CCPR1L into
CCPR1H
Note:
11.3.3
The maximum PWM resolution for a given PWM
frequency is given by the formula:
EQUATION 11-3:
The Timer2 postscaler (see Section 7.1
“Timer2 Operation”) is not used in the
determination of the PWM frequency. The
postscaler could be used to have a servo
update rate at a different frequency than
the PWM output.
PWM DUTY CYCLE
The PWM duty cycle is specified by writing to the
CCPR1L
register
and
to
the
DC1B<1:0>
(CCP1CON<5:4>) bits. Up to 10 bits of resolution is
available. The CCPR1L contains the eight MSbs and
the DC1B<1:0> contains the two LSbs. CCPR1L and
DC1B<1:0> can be written to at any time. In PWM
mode, CCPR1H is a read-only register. This 10-bit
value is represented by CCPR1L (CCP1CON<5:4>).
TABLE 11-4:
The polarity (active-high or active-low) and mode of the
signal
are
configured
by
the
P1M<1:0>
(CCP1CON<7:6>) and CCP1M<3:0> (CCP1CON<3:0>)
bits.
MAX. PWM RESOLUTION
PER FREQUENCY
F OSC
log ⎛ -------------------------------------------------------------⎞
⎝ F PWM • TMR2 Prescaler⎠
Resolution = --------------------------------------------------------------------------- bits
log ( 2 )
All control registers are double buffered and are loaded
at the beginning of a new PWM cycle (the period
boundary when Timer2 resets) in order to prevent
glitches on any of the outputs. The exception is the PWM
delay register, which is loaded at either the duty cycle
boundary or the period boundary (whichever comes
first). Because of the buffering, the module waits until the
timer resets, instead of starting immediately. This means
that enhanced PWM waveforms do not exactly match
the standard PWM waveforms, but are instead offset by
one full instruction cycle (4 TOSC).
Note:
If the PWM duty cycle value is longer than
the PWM period, the assigned PWM pin(s)
will remain unchanged.
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
PWM Frequency
1.22 kHz(1)
4.88 kHz(1)
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
6.6
Note 1:
Changing duty cycle will cause a glitch.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 117
PIC16F685/687/689/690
FIGURE 11-4:
PWM OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE)
0
<7:6>
00
PR2+1
Duty
Cycle
Signal
CCP1CON
Period
(Single Output)
P1A Modulated
Delay(1)
Delay(1)
P1A Modulated
(Half-bridge)
10
P1B Modulated
P1A Active
(Full-bridge,
Forward)
01
P1B Inactive
P1C Inactive
P1D Modulated
P1A Inactive
(Full-bridge,
Reverse)
11
P1B Modulated
P1C Active
P1D Inactive
Relationships:
• Period = 4 * TOSC * (PR2 + 1) * (TMR2 prescale value)
• Duty Cycle = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 prescale value)
• Delay = 4 * TOSC * (PWM1CON<6:0>)
Note 1: Dead band delay is programmed using the PWM1CON register (Section 11.3.7 “Programmable Dead Band Delay”).
FIGURE 11-5:
PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
0
CCP1CON
<7:6>
00
(Single Output)
Period
P1A Modulated
P1A Modulated
10
(Half-bridge)
PR2+1
Duty
Cycle
Signal
Delay(1)
Delay(1)
P1B Modulated
P1A Active
01
(Full-bridge,
Forward)
P1B Inactive
P1C Inactive
P1D Modulated
P1A Inactive
11
(Full-bridge,
Reverse)
P1B Modulated
P1C Active
P1D Inactive
Relationships:
• Period = 4 * TOSC * (PR2 + 1) * (TMR2 prescale value)
• Duty Cycle = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 prescale value)
• Delay = 4 * TOSC * (PWM1CON<6:0>)
Note
1:
DS41262A-page 118
Dead band delay is programmed using the PWM1CON register (Section 11.3.7 “Programmable Dead Band Delay”).
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.3.4
HALF-BRIDGE MODE
In the Half-bridge Output mode, two pins are used as
outputs to drive push-pull loads. The PWM output
signal is output on the RC5/CCP1/P1A pin, while the
complementary PWM output signal is output on the
RC4/C2OUT/P1B pin (Figure 11-6). This mode can be
used for half-bridge applications, as shown in
Figure 11-7, or for full-bridge applications, where four
power switches are being modulated with two PWM
signals.
In Half-bridge Output mode, the programmable dead
band delay can be used to prevent shoot-through
current in half-bridge power devices. The value of bits
PDC<6:0> (PWM1CON<6:0>) sets the number of
instruction cycles before the output is driven active. If
the value is greater than the duty cycle, the
corresponding output remains inactive during the entire
cycle. See Section 11.3.7 “Programmable Dead
Band Delay” for more details of the dead band delay
operations.
Since the P1A and P1B outputs are multiplexed with
the PORTC<5:4> data latches, the TRISC<5:4> bits
must be cleared to configure P1A and P1B as outputs.
FIGURE 11-6:
Period
Period
Duty Cycle
P1A(2)
td
td
P1B(2)
(1)
(1)
(1)
td = Dead Band Delay
Note 1:
2:
FIGURE 11-7:
HALF-BRIDGE PWM
OUTPUT
At this time, the TMR2 register is equal to the
PR2 register.
Output signals are shown as active-high.
EXAMPLES OF HALF-BRIDGE APPLICATIONS
V+
Standard Half-bridge Circuit (“Push-Pull”)
FET
Driver
+
V
-
P1A
PIC16F685/690
Load
FET
Driver
+
V
-
P1B
V-
Half-bridge Output Driving a Full-bridge Circuit
V+
FET
Driver
FET
Driver
P1A
PIC16F685/690
FET
Driver
Load
FET
Driver
P1B
V-
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 119
PIC16F685/687/689/690
11.3.5
FULL-BRIDGE MODE
In Full-bridge Output mode, four pins are used as
outputs; however, only two outputs are active at a time.
In the Forward mode, pin RC5/CCP1/P1A is
continuously active and pin RC2/AN6/P1D is modulated.
FIGURE 11-8:
In the Reverse mode, RC3/AN7/P1C pin is continuously
active and RC4/C2OUT/P1B pin is modulated. These
are illustrated in Figure 11-8.
P1A, P1B, P1C and P1D outputs are multiplexed with
the PORTC<5:2> data latches. The TRISC<5:2> bits
must be cleared to make the P1A, P1B, P1C and P1D
pins output.
FULL-BRIDGE PWM OUTPUT
Forward Mode
Period
P1A
(2)
Duty Cycle
P1B(2)
P1C(2)
P1D(2)
(1)
(1)
Reverse Mode
Period
Duty Cycle
P1A(2)
P1B(2)
P1C(2)
P1D(2)
(1)
Note 1:
2:
(1)
At this time, the TMR2 register is equal to the PR2 register.
Output signal is shown as active-high.
DS41262A-page 120
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 11-9:
EXAMPLE OF FULL-BRIDGE APPLICATION
V+
FET
Driver
QC
QA
FET
Driver
P1A
Load
P1B
PIC16F685/690
FET
Driver
P1C
FET
Driver
QD
QB
VP1D
11.3.5.1
Direction Change in Full-Bridge
Mode
In the Full-bridge Output mode, the P1M1 bit
(CCP1CON<7>) allows user to control the Forward/
Reverse direction. When the application firmware
changes this direction control bit, the module will
assume the new direction on the next PWM cycle.
Just before the end of the current PWM period, the
modulated outputs (P1B and P1D) are placed in their
inactive state, while the unmodulated outputs (P1A and
P1C) are switched to drive in the opposite direction.
This occurs in a time interval of (4 TOSC*(Timer2
Prescale value)) before the next PWM period begins.
The Timer2 prescaler will be either 1, 4 or 16,
depending on the value of the T2CKPS<1:0> bits
(T2CON<1:0>). During the interval from the switch of
the unmodulated outputs to the beginning of the next
period, the modulated outputs (P1B and P1D) remain
inactive. This relationship is shown in Figure 11-10.
Figure 11-11 shows an example where the PWM
direction changes from forward to reverse, at a near
100% duty cycle. At time t1, the output P1A and P1D
become inactive, while output P1C becomes active. In
this example, since the turn off time of the power
devices is longer than the turn on time, a shoot-through
current may flow through power devices QC and QD
(see Figure 11-9) for the duration of ‘t’. The same
phenomenon will occur to power devices QA and QB
for PWM direction change from reverse to forward.
If changing PWM direction at high duty cycle is required
for an application, one of the following requirements
must be met:
1.
2.
Reduce PWM duty cycle for one PWM period
before changing directions.
Use switch drivers that can drive the switches off
faster than they can drive them on.
Other options to prevent shoot-through current may
exist.
Note that in the Full-bridge Output mode, the ECCP+
module does not provide any dead band delay. In
general, since only one output is modulated at all times,
dead band delay is not required. However, there is a
situation where a dead band delay might be required.
This situation occurs when both of the following
conditions are true:
1.
2.
The direction of the PWM output changes when
the duty cycle of the output is at or near 100%.
The turn off time of the power switch, including
the power device and driver circuit, is greater
than the turn on time.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 121
PIC16F685/687/689/690
FIGURE 11-10:
PWM DIRECTION CHANGE
Period(1)
Signal
Period
P1A (Active-High)
P1B (Active-High)
DC
P1C (Active-High)
(2)
P1D (Active-High)
DC
Note 1:
2:
The direction bit in the ECCP Control register (CCP1CON<7>) is written any time during the PWM cycle.
When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle at intervals
of 4 TOSC, 16 TOSC or 64 TOSC, depending on the Timer2 prescaler value. The modulated P1B and P1D signals
are inactive at this time.
FIGURE 11-11:
PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
Forward Period
t1
Reverse Period
P1A
P1B
DC
P1C
P1D
DC
TON
External Switch C
TOFF
External Switch D
Potential
Shoot-Through
Current
Note 1:
T = TOFF - TON
All signals are shown as active-high.
2:
TON is the turn on delay of power switch QC and its driver.
3:
TOFF is the turn off delay of power switch QD and its driver.
DS41262A-page 122
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.3.6
PULSE STEERING MODE
The PWM Steering is available only when the
CCP1M<3:2> = 11 and P1M<1:0> = 00 (CCP1CON
register). Upon any chip Reset, the PSTRCON register
is initialized to enable the PWM output to P1A only.
Once the Single Output mode is selected by
CCP1M<3:0>, the user firmware can bring out the
same PWM signal to one, two, three or four output pins
by setting the appropriate STR<D:A> bits, as shown in
Table 11-5.
REGISTER 11-2:
Note:
The relevant TRIS bits must be set to
output (‘0’) to enable the pin output driver,
in order to see the PWM signal on the pin.
While the PWM Steering mode is active, CCP1M<1:0>
selects the PWM output polarity for the P1<D:A> pins.
See Register 11-1 (CCP1CON) for details.
The PWM auto-shutdown operation also applies to this
PWM Steering mode as described in the
Section 11.3.8 “Enhanced PWM Auto-shutdown”
and Section 11.3.11 “Effects of a Reset” and follows
ECCPAS values without regard to CCP1M<3:0>. An
Auto-Shutdown event will only affect pins that have
PWM outputs enabled.
PSTRCON – PULSE STEERING CONTROL REGISTER(1, 2) (ADDRESS: 19Dh)
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-1
—
—
—
STRSYNC
STRD
STRC
STRB
STRA
bit 7
bit 7-5
bit 4
bit 3
bit 2
bit 1
bit 0
bit 0
Unimplemented: Read as ‘0’
STRSYNC: Steering Sync bit
1 = Output steering update occurs on next PWM period
0 = Output steering update occurs at the beginning of the instruction cycle boundary
STRD: Steering Enable bit D
1 = P1D pin has the PWM waveform with polarity control from CCPM<1:0>
0 = P1D pin is assigned to port pin
STRC: Steering Enable bit C
1 = P1C pin has the PWM waveform with polarity control from CCPM<1:0>
0 = P1C pin is assigned to port pin
STRB: Steering Enable bit B
1 = P1B pin has the PWM waveform with polarity control from CCPM<1:0>
0 = P1B pin is assigned to port pin
STRA: Steering Enable bit A
1 = P1A pin has the PWM waveform with polarity control from CCPM<1:0>
0 = P1A pin is assigned to port pin
Note 1: PIC16F685/PIC16F690 only.
2: The PWM Steering is available only when the CCP1M<3:2> = 11 and
P1M<1:0> = 00 (CCP1CON register).
Legend:
R = Readable bit
-n = Value at POR
© 2005 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
Preliminary
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
DS41262A-page 123
PIC16F685/687/689/690
TABLE 11-5:
PWM STEERING OPERATION WHEN CCP1M<3:2>=11 AND P1M<1:0>=00
(CCP1CON REGISTER)
STRD
STRC
STRB
STRA
P1D
P1C
P1B
P1A
0
0
0
0
Port
Port
Port
Port
0
0
0
1
Port
Port
Port
P1A
0
0
1
0
Port
Port
P1B
Port
0
0
1
1
Port
Port
P1B
P1A
0
1
0
0
Port
P1C
Port
Port
0
1
0
1
Port
P1C
Port
P1A
0
1
1
0
Port
P1C
P1B
Port
0
1
1
1
Port
P1C
P1B
P1A
1
0
0
0
P1D
Port
Port
Port
1
0
0
1
P1D
Port
Port
P1A
1
0
1
0
P1D
Port
P1B
Port
1
0
1
1
P1D
Port
P1B
P1A
1
1
0
0
P1D
P1C
Port
Port
1
1
0
1
P1D
P1C
Port
P1A
1
1
1
0
P1D
P1C
P1B
Port
1
1
1
P1D
P1C
P1B
P1A
1
Note:
‘Port’ as described when NOT in PWM mode.
DS41262A-page 124
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.3.6.1
Steering Synchronization
The STRSYNC bit gives the user two selections of
when the steering event will happen. When the
STRSYNC bit is ‘0’, the steering event will happen at
the end of the instruction that writes to the STRCON
register. In this case, the output signal at the P1<D:A>
pins may be an incomplete PWM waveform. This
operation is useful when the user firmware needs to
immediately remove a PWM signal from the pin.
FIGURE 11-12:
When the STRSYNC bit is ‘1’, the effective steering
update will happen at the beginning of the next PWM
period. In this case, steering on/off the PWM output will
always produce a complete PWM waveform.
Figures 11-12 and 11-13 illustrates the timing diagrams
of the PWM steering depending on the STRSYNC setting.
STEERING EVENT AT END OF INSTRUCTION (STRSYNC = 0)
PWM Period
PWM
STRn
P1<D:A>
q4
q4
Port Data
Port Data
P1n = PWM
FIGURE 11-13:
STEERING EVENT AT BEGINNING OF INSTRUCTION (STRSYNC = 1)
PWM
STRn
P1<D:A>
Port Data
Port Data
P1n – PWM
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 125
PIC16F685/687/689/690
11.3.7
PROGRAMMABLE DEAD BAND
DELAY
In half-bridge applications where all power switches are
modulated at the PWM frequency at all times, the
power switches normally require more time to turn off
than to turn on. If both the upper and lower power
switches are switched at the same time (one turned on,
and the other turned off), both switches may be on for
a short period of time until one switch completely turns
off. During this brief interval, a very high current
(shoot-through current) may flow through both power
switches, shorting the bridge supply. To avoid this
potentially destructive shoot-through current from
flowing during switching, turning on either of the power
switches is normally delayed to allow the other switch
to completely turn off.
In the Half-bridge Output mode, a digitally programmable
dead band delay is available to avoid shoot-through
current from destroying the bridge power switches. The
delay occurs at the signal transition from the non-active
state to the active state. See Figure 11-6 for illustration.
The lower seven bits of the PWM1CON register
(Register 11-3) sets the delay period in terms of
microcontroller instruction cycles (TCY or 4 TOSC).
REGISTER 11-3:
PWM1CON – ENHANCED PWM CONFIGURATION REGISTER(1) (ADDRESS: 1Ch)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
PRSEN
PDC6
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
bit 7
bit 7
bit 6-0
bit 0
PRSEN: PWM Restart Enable bit
1 = Upon auto-shutdown, the ECCPASE bit clears automatically once the shutdown event
goes away; the PWM restarts automatically.
0 = Upon auto-shutdown, ECCPASE must be cleared in software to restart the PWM.
PDC<6:0>: PWM Delay Count bits
PDCn = Number of FOSC/4 (4*TOSC) cycles between the scheduled time when a PWM signal
should transition active, and the actual time it transitions active.
Note 1: PIC16F685/PIC16F690 only.
Legend:
R = Readable bit
- n = Value at POR
DS41262A-page 126
W = Writable bit
‘1’ = Bit is set
Preliminary
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.3.8
ENHANCED PWM
AUTO-SHUTDOWN
When the ECCP is programmed for any of the
enhanced PWM modes, the active output pins may be
configured
for
auto-shutdown.
Auto-shutdown
immediately places the enhanced PWM output pins
into a defined shutdown state when a shutdown event
occurs.
A shutdown event can be caused by either of the two
comparators or the INT pin (or any combination of
these three sources). The comparators may be used to
monitor a voltage input proportional to a current being
monitored in the bridge circuit. If the voltage exceeds a
threshold, the comparator switches state and triggers a
shutdown. Alternatively, a digital signal on the INT pin
can also trigger a shutdown. The auto-shutdown
feature can be disabled by not selecting any auto-shutdown sources. The auto-shutdown sources to be used
are selected using the ECCPAS<2:0> bits
(ECCPAS<6:4>).
REGISTER 11-4:
When a shutdown occurs, the output pins are
asynchronously placed in their shutdown states,
specified by the PSSAC<3:2> and PSSBD<1:0> bits
(ECCPAS<3:0>). Each pin pair (P1A/P1C and P1B/P1D)
may be set to drive high, drive low, or be tri-stated (not
driving). The ECCPASE bit (ECCPAS<7>) is also set to
hold the enhanced PWM outputs in their shutdown
states.
The ECCPASE bit is set by hardware when a shutdown
event occurs. If Auto-restarts are not enabled, the
ECCPASE bit is cleared by firmware when the cause of
the shutdown clears. If Auto-restarts are enabled, the
ECCPASE bit is automatically cleared when the cause of
the auto-shutdown has cleared. See Section 11.3.8.1
“Auto-shutdown and Auto-restart” for more
information.
ECCPAS – ENHANCED CAPTURE/COMPARE/PWM+ AUTO-SHUTDOWN
CONTROL REGISTER(1) (ADDRESS: 1Dh)
R/W-0
R/W-0
R/W-0
R/W-0
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0
R/W-0
R/W-0
R/W-0
R/W-0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
bit 7
bit 7
bit 6-4
bit 3-2
bit 1-0
bit 0
ECCPASE: ECCP Auto-shutdown Event Status bit
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
0 = ECCP outputs are operating
ECCPAS<2:0>: ECCP Auto-shutdown Source Select bits
000 = Auto-shutdown is disabled
001 = Comparator 1 output change
010 = Comparator 2 output change
011 = Either Comparator 1 or 2 change
100 = VIL on INT pin
101 = VIL on INT pin or Comparator 1 change
110 = VIL on INT pin or Comparator 2 change
111 = VIL on INT pin or Comparator 1 or Comparator 2 change
PSSACn: Pin P1A and P1C Shutdown State Control bits
00 = Drive Pins P1A and P1C to ‘0’
01 = Drive Pins P1A and P1C to ‘1’
1x = Pins P1A and P1C tri-state
PSSBDn: Pin P1B and P1D Shutdown State Control bits
00 = Drive Pins P1B and P1D to ‘0’
01 = Drive Pins P1B and P1D to ‘1’
1x = Pins P1B and P1D tri-state
Note 1: PIC16F685/PIC16F690 only.
Legend:
R = Readable bit
- n = Value at POR
© 2005 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
Preliminary
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
DS41262A-page 127
PIC16F685/687/689/690
11.3.8.1
Auto-shutdown and Auto-restart
11.3.9
The auto-shutdown feature can be configured to allow
auto-restarts of the module following a shutdown event.
This is enabled by setting the PRSEN bit of the
PWM1CON register (PWM1CON<7>).
In Shutdown mode with PRSEN = 1 (Figure 11-14), the
ECCPASE bit will remain set for as long as the cause
of the shutdown continues. When the shutdown
condition clears, the ECCPASE bit is cleared. If
PRSEN = 0 (Figure 11-15), once a shutdown condition
occurs, the ECCPASE bit will remain set until it is
cleared by firmware. Once ECCPASE is cleared, the
enhanced PWM will resume at the beginning of the
next PWM period.
Note:
Writing to the ECCPASE bit is disabled
while a shutdown condition is active.
Independent of the PRSEN bit setting, whether the
auto-shutdown source is one of the comparators or
INT, the shutdown condition is a level. The ECCPASE
bit cannot be cleared as long as the cause of the
shutdown persists.
The Auto-shutdown mode can be forced by writing a ‘1’
to the ECCPASE bit.
FIGURE 11-14:
START-UP CONSIDERATIONS
When the ECCP+ module is used in the PWM mode,
the application hardware must use the proper external
pull-up and/or pull-down resistors on the PWM output
pins. When the microcontroller is released from Reset,
all of the I/O pins are in the high-impedance state. The
external circuits must keep the power switch devices in
the OFF state, until the microcontroller drives the I/O
pins with the proper signal levels, or activates the PWM
output(s).
The CCP1M<1:0> bits (CCP1CON<1:0>) allow the user
to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output pins
(P1A/P1C and P1B/P1D). The PWM output polarities
must be selected before the PWM pins are configured as
outputs. Changing the polarity configuration while the
PWM pins are configured as outputs is not recommended
since it may result in damage to the application circuits.
The P1A, P1B, P1C and P1D output latches may not
be in the proper states when the PWM module is
initialized. Enabling the PWM pins for output at the
same time as the ECCP+ module may cause damage
to the application circuit. The ECCP+ module must be
enabled in the proper Output mode and complete a full
PWM cycle before configuring the PWM pins as
outputs. The completion of a full PWM cycle is
indicated by the TMR2IF bit being set as the second
PWM period begins.
PWM AUTO-SHUTDOWN (PRSEN = 1, AUTO-RESTART ENABLED)
PWM Period
Shutdown Event
ECCPASE bit
PWM Activity
Normal PWM
Start of
PWM Period
FIGURE 11-15:
Shutdown
Shutdown
Event Occurs Event Clears
PWM
Resumes
PWM AUTO-SHUTDOWN (PRSEN = 0, AUTO-RESTART DISABLED)
PWM Period
Shutdown Event
ECCPASE bit
PWM Activity
Normal PWM
Start of
PWM Period
DS41262A-page 128
ECCPASE
Cleared by
Shutdown
Shutdown Firmware PWM
Event Occurs Event Clears
Resumes
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
11.3.10
OPERATION IN SLEEP MODE
11.3.12
SETUP FOR PWM OPERATION
In Sleep mode, all clock sources are disabled. Timer2
will not increment, and the state of the module will not
change. If the ECCP pin is driving a value, it will
continue to drive that value. When the device wakes
up, it will continue from this state.
The following steps should be taken when configuring
the ECCP+ module for PWM operation:
11.3.10.1
2.
3.
OPERATION WITH FAIL-SAFE
CLOCK MONITOR
1.
If the Fail-Safe Clock Monitor is enabled, a clock failure
will force the ECCP to be clocked from the internal
oscillator clock source, which may have a different
clock frequency than the primary clock.
See Section 3.0 “Clock Sources” for additional
details.
11.3.11
4.
EFFECTS OF A RESET
Both Power-on Reset and Resets will force all ports to
Input mode and the ECCP registers to their Reset
states.
This forces the Enhanced CCP module to reset to a
state compatible with the standard CCP module.
5.
6.
7.
8.
9.
© 2005 Microchip Technology Inc.
Preliminary
Configure the PWM pins P1A and P1B (and
P1C and P1D, if used) as inputs by setting the
corresponding TRISC bits.
Set the PWM period by loading the PR2 register.
Configure the ECCP+ module for the desired
PWM mode and configuration by loading the
CCP1CON register with the appropriate values:
• Select one of the available output
configurations and direction with the
P1M<1:0> bits.
• Select the polarities of the PWM output
signals with the CCP1M<3:0> bits.
Set the PWM duty cycle by loading the CCPR1L
register and CCP1CON<5:4> bits.
For Half-bridge Output mode, set the dead band
delay by loading PWM1CON<6:0> with the
appropriate value.
If auto-shutdown operation is required, load the
ECCPAS register:
• Select the auto-shutdown sources using the
ECCPAS<2:0> bits.
• Select the shutdown states of the PWM
output pins using PSSAC<3:2> and
PSSBD<1:0> bits.
• Set the ECCPASE bit (ECCPAS<7>).
• Configure the comparators using the
CM1CON0 and CM2CON0 registers
(Registers 8-1 and 8-2).
• Configure the comparator inputs as analog
inputs.
If auto-restart operation is required, set the
PRSEN bit (PWM1CON<7>).
Configure and start TMR2:
• Clear the TMR2 interrupt flag bit by clearing
the TMR2IF bit (PIR1<1>).
• Set the TMR2 prescale value by loading the
T2CKPS bits (T2CON<1:0>).
• Enable Timer2 by setting the TMR2ON bit
(T2CON<2>).
Enable PWM outputs after a new PWM cycle
has started:
• Wait until TMR2 overflows (TMR2IF bit is set).
• Enable the CCP1/P1A, P1B, P1C and/or P1D
pin outputs by clearing the respective TRISC
bits.
• Clear the ECCPASE bit (ECCPAS<7>).
DS41262A-page 129
PIC16F685/687/689/690
TABLE 11-6:
Addr
REGISTERS ASSOCIATED WITH PWM AND TIMER2(1)
Value on
POR, BOR
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0Bh/8Bh/
INTCON
10Bh/18Bh
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x 0000 000x
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000 -000 0000
0Ch
PIR1
11h
TMR2
12h
T2CON
15h
CCPR1L
Capture/Compare/PWM Register1 Low Byte
16h
CCPR1H
Capture/Compare/PWM Register1 High Byte
17h
CCP1CON
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
0000 0000 0000 0000
1Ch
PWM1CON
PRSEN
PDC6
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
0000 0000 0000 0000
1Dh
ECCPAS
PSSAC1
PSSAC0
PSSBD1
PSSBD0
0000 0000 0000 0000
87h/187h
TRISC
8Ch
PIE1
92h
PR2
19Dh
PSTRCON
Legend:
Note
Timer2 Module Register
—
0000 0000 0000 0000
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
TRISC7
TRISC6
TRISC5
TRISC4
TRISC3
TRISC2
TRISC1
TRISC0
1111 1111 1111 1111
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IF
TMR1IF
-000 0000 -000 0000
STRSYNC
STRD
STRC
STRB
STRA
---0 0001 ---0 0001
Timer2 Module Period Register
—
—
—
1111 1111 1111 1111
– = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the Capture, Compare or Timer1
module.
1:
PIC16F685/PIC16F690 only.
DS41262A-page 130
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
12.0
ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module is the serial I/O
module available for PIC16F685/687/689/690. (EUSART
is also known as a Serial Communications Interface or
SCI). The EUSART can be configured in full-duplex
Asynchronous mode that can communicate with
peripheral devices, such as CRT terminals and personal
computers, or it can also be configured as a half-duplex
Synchronous mode, which can communicate with
peripheral devices, such as A/D or D/A integrated
circuits, serial EEPROMs, etc.
The EUSART module implements additional features
including automatic baud rate detection and calibration,
automatic wake-up on Break reception and 13-bit Break
character transmit. These features make the EUSART
ideally suited for use in Local Interconnect Network
(LIN) bus systems.
12.1
Clock Accuracy With
Asynchronous Operation
The factory calibrates the internal oscillator block
output (INTOSC) for 8 MHz. However, this frequency
may drift as VDD or temperature changes, and this
directly affects the asynchronous baud rate generator.
Two methods may be used to adjust the baud rate
clock, but both require a reference clock source of
some kind.
The first (preferred) method uses the OSCTUNE
register to adjust the INTOSC output back to 8 MHz.
Adjusting the value in the OSCTUNE register allows for
fine resolution changes to the system clock source (see
Section 3.4 “Internal Clock Modes” for more
information).
The other method adjusts the value in the baud rate
generator. There may not be fine enough resolution
when adjusting the Baud Rate Generator to compensate
for a gradual change in the peripheral clock frequency.
The EUSART can be configured in the following
modes:
• Asynchronous (full-duplex) with:
- Auto-wake-up on Break
- Auto-baud calibration
- 13-bit Break character transmission
• Synchronous – Master (half-duplex) with
selectable clock polarity
• Synchronous – Slave (half-duplex) with selectable
clock polarity
In order to configure pins RB6/SCK/SCL and
RB7/TX/CK
as
the
Universal
Synchronous
Asynchronous Receiver Transmitter:
• SPEN (RCSTA<7>) bit must be set (= 1),
• TRISB<6> bit must be set (= 1), and
• TRISB<7> bit must be set (= 1).
Note:
The EUSART control will automatically
reconfigure the I/O pin from input to output
as needed.
The operation of the EUSART module is controlled
through three registers:
•
•
•
•
Transmit Status and Control (TXSTA)
Receive Status and Control (RCSTA)
Baud Rate Control (BAUDCTL)
Baud Rate registers (SPBRGH:SPBRG)
See Registers 12-1, 12-2 and 12-3 for more detail.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 131
PIC16F685/687/689/690
REGISTER 12-1:
TXSTA – TRANSMIT STATUS AND CONTROL REGISTER(1) (ADDRESS: 98h)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-1
R/W-0
CSRC
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
bit 7
bit 0
bit 7
CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6
TX9: 9-bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5
TXEN: Transmit Enable bit
1 = Transmit enabled
0 = Transmit disabled
Note:
SREN/CREN overrides TXEN in Sync mode.
bit 4
SYNC: EUSART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3
SENB: Send Break Character bit
Asynchronous mode:
1 = Send Sync Break on next transmission (cleared by hardware upon completion)
0 = Sync Break transmission completed
Synchronous mode:
Don’t care
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 address/data bit or a parity bit.
Note 1: PIC16F687/PIC16F689/PIC16F690 only.
Legend:
DS41262A-page 132
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 12-2:
RCSTA – RECEIVE STATUS AND CONTROL REGISTER(1) (ADDRESS: 18h)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R-0
R-x
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
bit 7
bit 0
bit 7
SPEN: Serial Port Enable bit
1 = Serial port enabled
0 = Serial port disabled (holds module in Reset)
bit 6
RX9: 9-bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5
SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care
Synchronous mode – Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode – Slave:
Don’t care
bit 4
CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3
ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, enable interrupt and load the receive buffer when RSR<8> is
set
0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 8-bit (RX9 = 0):
Don’t care
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
This can be address/data bit or a parity bit and must be calculated by user firmware.
Note 1: PIC16F687/PIC16F689/PIC16F690 only.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 133
PIC16F685/687/689/690
REGISTER 12-3:
BAUDCTL – BAUD RATE CONTROL REGISTER(1) (ADDRESS: 9Bh)
R-0
R-1
U-0
R/W-0
R/W-0
U-0
R/W-0
R/W-0
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
bit 7
bit 0
bit 7
ABDOVF: Auto-Baud Detect Overflow bit
Asynchronous mode:
1 = Auto-baud timer overflowed
0 = Auto-baud timer did not overflow
Synchronous mode:
Don’t care
bit 6
RCIDL: Receive IDLE Flag bit
Asynchronous mode:
1 = Receiver is IDLE
0 = Start bit has been received and the receiver is receiving
Synchronous mode:
Don’t care
bit 5
Unimplemented: Read as ‘0’
bit 4
SCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
1 = Transmit inverted data to the RB7/TX/CK pin
0 = Transmit non-inverted data to the RB7/TX/CK pin
Synchronous mode:
1 = Data is clocked on rising edge of the clock
0 = Data is clocked on falling edge of the clock
bit 3
BRG16: 16-bit Baud Rate Generator bit
1 = 16-bit baud rate generator is used
0 = 8-bit baud rate generator is used
bit 2
Unimplemented: Read as ‘0’
bit 1
WUE: Wake-up Enable bit
1 = Next falling RX/DT edge will set RCIF and wake-up device if it is asleep (automatically
cleared on next rising edge after falling edge)
0 = RX/DT edges do not generate interrupts
bit 0
ABDEN: Auto-Baud Detect Enable bit
Asynchronous mode:
1 = Auto-Baud mode is enabled (clears when auto-baud is complete)
0 = Auto-Baud mode is disabled
Synchronous mode:
Don’t care
Note 1: PIC16F687/PIC16F689/PIC16F690 only.
Legend:
DS41262A-page 134
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
12.2
12.2.1
EUSART Baud Rate Generator
(BRG)
The BRG is a dedicated 8-bit or 16-bit generator that
supports both the Asynchronous and Synchronous
modes of the EUSART. By default, the BRG operates
in 8-bit mode; setting the BRG16 bit (BAUDCTL<3>)
selects 16-bit mode.
The SPBRGH:SPBRG register pair controls the period
of a free running timer. In Asynchronous mode, bits
BRGH (TXSTA<2>) and BRG16 also control the baud
rate. In Synchronous mode, bit BRGH is ignored.
Table 12-1 shows the formula for computation of the
baud rate for different EUSART modes, which only
apply in Synchronous Master mode (internally generated clock).
Given the desired baud rate and FOSC, the nearest
integer value for the SPBRGH:SPBRG registers can be
calculated using the formulas in Table 12-1. From this,
the error in baud rate can be determined. An example
calculation is shown in Example 12-1. Typical baud
rates and error values for the various asynchronous
modes are shown in Table 12-2. It may be
advantageous to use the high baud rate (BRGH = 1),
or the 16-bit BRG to reduce the baud rate error, or
achieve a slow baud rate for a fast oscillator frequency.
SAMPLING
The data on the RB5/AN11/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.
EXAMPLE 12-1:
For a device with FOSC of 16 MHz, desired baud rate
of 9600, Asynchronous mode, 8-bit BRG:
FOSC
Desired Baud Rate = ------------------------------------------------------------------------64 ( [SPBRGH:SPBRG] + 1 )
Solving for SPBRGH:SPBRG:
FOSC
-------------------------------------------Desired Baud Rate
X = --------------------------------------------- – 1
64
16000000
-----------------------9600
= ------------------------ – 1
64
= [ 25.042 ] = 25
16000000
Calculated Baud Rate = --------------------------64 ( 25 + 1 )
= 9615
Calc. Baud Rate – Desired Baud Rate
Error = -------------------------------------------------------------------------------------------Desired Baud Rate
Writing a new value to the SPBRGH:SPBRG registers
causes the BRG timer to be reset (or cleared). This
ensures the BRG does not wait for a timer overflow
before outputting the new baud rate.
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit
and make sure that the receive operation is IDLE
before changing the system clock.
TABLE 12-1:
CALCULATING BAUD
RATE ERROR
( 9615 – 9600 )
= ---------------------------------- = 0.16%
9600
Note:
When BRGH = 1 and BRG16 = 1 then
SPBRGH:SPBRG values ≤ 4 are invalid.
BAUD RATE FORMULAS
Configuration Bits
BRG/EUSART Mode
SYNC
BRG16
Baud Rate Formula
BRGH
0
0
0
8-bit/Asynchronous
FOSC/[64 (n+1)]
0
0
1
8-bit/Asynchronous
FOSC/[16 (n+1)]
0
1
0
16-bit/Asynchronous
0
1
1
16-bit/Asynchronous
1
0
x
8-bit/Synchronous Master
1
1
x
16-bit/Synchronous Master
FOSC/[4 (n+1)]
Legend: x = Don’t care, n = value of SPBRGH:SPBRG register pair
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 135
PIC16F685/687/689/690
TABLE 12-2:
Addr
REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR(1)
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
18h
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
98h
TXSTA
CSRC
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
99h
SPBRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
9Ah
SPBRGH
BRG15
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
9Bh
BAUDCTL
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
Legend:
Note
x = unknown, u = unchanged, - = unimplemented locations read as ‘0’. Shaded cells are not used by oscillators.
1:
PIC16F687/PIC16F689/PIC16F690 only.
DS41262A-page 136
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 12-3:
BAUD RATES FOR ASYNCHRONOUS MODES
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
(K)
FOSC = 20.000 MHz
Actual
Rate
(K)
%
Error
FOSC = 10.000 MHz
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3
—
—
—
—
—
—
—
—
—
1.2
1.221
1.73
255
1.202
0.16
129
1201
-0.16
103
2.4
2.404
0.16
129
2.404
0.16
64
2403
-0.16
51
9.6
9.766
1.73
31
9.766
1.73
15
9615
-0.16
12
19.2
19.531
1.73
15
19.531
1.73
7
—
—
—
57.6
62.500
8.51
4
52.083
-9.58
2
—
—
—
115.2
104.167
-9.58
2
78.125
-32.18
1
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
(K)
FOSC = 4.000 MHz
Actual
Rate
(K)
%
Error
0.3
0.300
0.16
1.2
1.202
0.16
FOSC = 2.000 MHz
Actual
Rate
(K)
%
Error
207
300
-0.16
51
1201
-0.16
SPBRG
value
(decimal)
FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
103
300
-0.16
51
25
1201
-0.16
12
SPBRG
value
(decimal)
SPBRG
value
(decimal)
2.4
2.404
0.16
25
2403
-0.16
12
—
—
—
9.6
8.929
-6.99
6
—
—
—
—
—
—
19.2
20.833
8.51
2
—
—
—
—
—
—
57.6
62.500
8.51
0
—
—
—
—
—
—
115.2
62.500
-45.75
0
—
—
—
—
—
—
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
(K)
FOSC = 20.000 MHz
Actual
Rate
(K)
%
Error
FOSC = 10.000 MHz
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
2.4
—
—
—
2.441
1.73
255
2403
-0.16
9.6
9.615
0.16
129
9.615
0.16
64
9615
-0.16
207
51
19.2
19.231
0.16
64
19.531
1.73
31
19230
-0.16
25
57.6
56.818
-1.36
21
56.818
-1.36
10
55555
3.55
8
115.2
113.636
-1.36
10
125.000
8.51
4
—
—
—
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
(K)
FOSC = 4.000 MHz
Actual
Rate
(K)
%
Error
FOSC = 2.000 MHz
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3
—
—
—
—
—
—
300
-0.16
207
1.2
1.202
0.16
207
1201
-0.16
103
1201
-0.16
51
2.4
2.404
0.16
103
2403
-0.16
51
2403
-0.16
25
9.6
9.615
0.16
25
9615
-0.16
12
—
—
—
19.2
19.231
0.16
12
—
—
—
—
—
—
57.6
62.500
8.51
3
—
—
—
—
—
—
115.2
125.000
8.51
1
—
—
—
—
—
—
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 137
PIC16F685/687/689/690
TABLE 12-3:
BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
(K)
FOSC = 20.000 MHz
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
0.02
-0.03
4165
1041
0.300
1.200
2.399
-0.03
520
Actual
Rate
(K)
%
Error
0.3
1.2
0.300
1.200
2.4
SPBRG
value
FOSC = 8.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
0.02
-0.03
2082
520
300
1201
-0.04
-0.16
1665
415
2.404
0.16
259
2403
-0.16
207
SPBRG
value
SPBRG
value
(decimal)
9.6
9.615
0.16
129
9.615
0.16
64
9615
-0.16
51
19.2
19.231
0.16
64
19.531
1.73
31
19230
-0.16
25
57.6
56.818
-1.36
21
56.818
-1.36
10
55555
3.55
8
115.2
113.636
-1.36
10
125.000
8.51
4
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
(K)
FOSC = 4.000 MHz
Actual
Rate
(K)
%
Error
0.3
1.2
0.300
1.202
0.04
0.16
2.4
2.404
0.16
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
832
207
300
1201
-0.16
-0.16
103
2403
SPBRG
value
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
415
103
300
1201
-0.16
-0.16
207
51
-0.16
51
2403
-0.16
25
SPBRG
value
SPBRG
value
(decimal)
9.6
9.615
0.16
25
9615
-0.16
12
—
—
—
19.2
19.231
0.16
12
—
—
—
—
—
—
57.6
62.500
8.51
3
—
—
—
—
—
—
115.2
125.000
8.51
1
—
—
—
—
—
—
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
(K)
FOSC = 20.000 MHz
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
0.00
16665
0.300
0.00
0.02
4165
1.200
0.02
2.400
0.02
2082
2.402
9.6
9.596
-0.03
520
19.2
19.231
0.16
259
57.6
57.471
-0.22
86
115.2
116.279
0.94
42
Actual
Rate
(K)
%
Error
0.3
0.300
1.2
1.200
2.4
SPBRG
value
FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
8332
300
-0.01
6665
2082
1200
-0.04
1665
0.06
1040
2400
-0.04
832
9.615
0.16
259
9615
-0.16
207
19.231
0.16
129
19230
-0.16
103
58.140
0.94
42
57142
0.79
34
113.636
-1.36
21
117647
-2.12
16
SPBRG
value
(decimal)
SPBRG
value
(decimal)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 2.000 MHz
Actual
Rate
(K)
%
Error
3332
300
-0.04
832
1201
-0.16
0.16
415
2403
9.615
0.16
103
19.231
0.16
Actual
Rate
(K)
%
Error
0.3
0.300
0.01
1.2
1.200
0.04
2.4
2.404
9.6
19.2
FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
1665
300
-0.04
832
415
1201
-0.16
207
-0.16
207
2403
-0.16
103
9615
-0.16
51
9615
-0.16
25
51
19230
-0.16
25
19230
-0.16
12
SPBRG
value
(decimal)
SPBRG
value
(decimal)
SPBRG
value
(decimal)
57.6
58.824
2.12
16
55555
3.55
8
—
—
—
115.2
111.111
-3.55
8
—
—
—
—
—
—
DS41262A-page 138
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
12.2.2
AUTO-BAUD DETECT
The EUSART module supports the automatic detection
and calibration of baud rate. This feature is active only
in Asynchronous mode and while the WUE bit is clear.
The automatic baud rate measurement sequence
(Figure 12-1) begins whenever a Start bit is received
and the ABDEN bit is set. The calculation is selfaveraging.
In the Auto-Baud Detect (ABD) mode, the clock to the
BRG is reversed. Rather than the BRG clocking the
incoming RX signal, the RX signal is timing the BRG. In
ABD mode, the internal baud rate generator is used as
a counter to time the bit period of the incoming serial
byte stream.
If the BRG counter rolls over, the ABDOVF
(BAUDCTL<7>) and the RCIF bits are set to indicate
BRG has overflowed. The ABDOVF bit is set by
hardware and can only be cleared by the user. When
an overflow occurs, Auto-baud Detect remains active
and the ABDEN (BAUDCTL<0>) bit remains set. The
ABDOVF will remain set and not able to be cleared
until the ABDEN is reset to ‘0’. The RCIF must be
cleared by reading the RCREG or clearing the SPEN
bit.
Once the ABDEN bit is set, the state machine will clear
the BRG and look for a Start bit. The Auto-Baud Detect
must receive a byte with the value 55h (ASCII “U”, which
is also the LIN bus Sync character), in order to calculate
the proper bit rate. The measurement is taken over both
a low and a high bit time in order to minimize any effects
caused by asymmetry of the incoming signal. After a
Start bit, the SPBRG begins counting up using the
preselected clock source on the first rising edge of RX.
After eight bits on the RX pin, or the fifth rising edge, an
accumulated value totalling the proper BRG period is left
in the SPBRGH:SPBRG registers. Once the 5th edge is
seen (should correspond to the Stop bit), the ABDEN bit
is automatically cleared.
While the ABD sequence takes place, the EUSART
state machine is held in IDLE. The RCIF interrupt is set
once the fifth rising edge on RX is detected. The value
in the RCREG needs to be read to clear the RCIF interrupt. RCREG content should be discarded.
Note 1: If the WUE bit is set with the ABDEN bit,
auto-baud rate detection will occur on the
byte following the Break character (see
Section 12.3.4 “Auto-Wake-up on RX
Pin Falling Edge”).
2: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some
combinations
of
oscillator
frequency and EUSART baud rates are
not possible due to bit error rates. Overall
system timing and communication baud
rates must be taken into consideration
when using the Auto-Baud Detect
feature.
TABLE 12-4:
BRG COUNTER CLOCK
RATES
BRG16
BRGH
BRG Counter Clock
0
0
FOSC/512
0
1
FOSC/128
1
0
FOSC/128
1
FOSC/32
1
Note:
During the ABD sequence, SPBRG and
SPBRGH are both used as a 16-bit
counter, independent of BRG16 setting.
While calibrating the baud rate period, the BRG
registers are clocked at 1/8th the pre-configured clock
rate. Note that the BRG clock will be configured by the
BRG16 and BRGH bits. Independent of the BRG16 bit
setting, both the SPBRG and SPBRGH will be used as
a 16-bit counter. This allows the user to verify that no
carry occurred for 8-bit modes, by checking for 00h in
the SPBRGH register. Refer to Table 12-4 for counter
clock rates to the BRG.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 139
PIC16F685/687/689/690
FIGURE 12-1:
AUTOMATIC BAUD RATE CALCULATION
XXXXh
BRG Value
RX pin
0000h
001Ch
Start
Edge #1
Bit 1
Bit 0
Edge #2
Bit 3
Bit 2
Edge #3
Bit 5
Bit 4
Edge #4
Bit 7
Bit 6
Edge #5
Stop Bit
BRG Clock
Auto Cleared
Set by User
ABDEN bit
RCIDL
RCIF bit
(Interrupt)
Read
RCREG
SPBRG
XXXXh
1Ch
SPBRGH
XXXXh
00h
Note
1:
DS41262A-page 140
The ABD sequence requires the EUSART module to be configured in Asynchronous mode and WUE = 0.
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
12.3
12.3.1
EUSART Asynchronous Mode
The Asynchronous mode of operation is selected by
clearing the SYNC bit (TXSTA<4>). In this mode, the
EUSART 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/16-bit baud rate generator can be used
to derive standard baud rate frequencies from the
oscillator.
The EUSART transmits and receives the LSb first. The
EUSART’s transmitter and receiver are functionally
independent, but use the same data format and baud
rate. The baud rate generator produces a clock, either
x16 or x64 of the bit shift rate, depending on the BRGH
and BRG16 bits (TXSTA<2> and BAUDCTL<3>).
Parity is not supported by the hardware, but can be
implemented in software and stored as the 9th data bit.
Asynchronous mode is available in all times. It is
available in Sleep mode only when auto-wake-up on
Sync Break is enabled. The baud rate generator values
may need to be adjusted if the clocks are changed.
When operating in Asynchronous mode, the EUSART
module consists of the following important elements:
•
•
•
•
•
•
•
Baud Rate Generator
Sampling Circuit
Asynchronous Transmitter
Asynchronous Receiver
Auto-wake-up on Sync Break Character
13-bit Break Character Transmit
Auto-Baud Detection
EUSART ASYNCHRONOUS
TRANSMITTER
The EUSART transmitter block diagram is shown in
Figure 12-2. The heart of the transmitter is the Transmit
(serial) Shift Register (TSR). The shift register obtains
its data from the read/write transmit buffer, TXREG. The
TXREG register is loaded with data in software. The
TSR register is not loaded until the Stop bit has been
transmitted from the previous load. As soon as the Stop
bit is transmitted, the TSR is loaded with new data from
the TXREG register (if available).
Once the TXREG register transfers the data to the TSR
register (occurs in one TCY), the TXREG register is
empty and flag bit TXIF (PIR1<4>) is set. This interrupt
can be 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. Flag bit TXIF is not cleared immediately upon
loading the transmit buffer register TXREG. TXIF
becomes valid in the second instruction cycle following
the load instruction. Polling TXIF immediately following
a load of TXREG will return invalid results.
While flag bit TXIF indicates the status of the TXREG
register, another bit, TRMT (TXSTA<1>), shows the
status of the TSR register. Status bit TRMT is a
read-only bit, which is set when the TSR register is
empty. No interrupt logic is tied to this bit, so the user
has to poll this bit in order to determine if the TSR
register is empty.
Note 1: The TSR register is not mapped in data
memory, so it is not available to the user.
2: Flag bit TXIF is set when enable bit TXEN
is set.
To set up an Asynchronous Transmission:
1.
2.
3.
4.
5.
6.
7.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Load data to the TXREG register (starts
transmission).
If using interrupts, ensure that the GIE and PEIE bits in
the INTCON register (INTCON<7:6>) are set.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 141
PIC16F685/687/689/690
FIGURE 12-2:
EUSART TRANSMIT BLOCK DIAGRAM
Data Bus
TXIF
TXREG Register
TXIE
8
MSb
RB7/TX/CK Pin
LSb
• • •
(8)
Pin Buffer
and Control
0
TSR Register
Interrupt
Baud Rate CLK
TXEN
TRMT
BRG16
SPBRGH
SPEN
SPBRG
TX9
Baud Rate Generator
TX9D
FIGURE 12-3:
ASYNCHRONOUS TRANSMISSION
Write to TXREG
BRG Output
(Shift Clock)
Word 1
RB7/TX/CK
pin
Start bit
FIGURE 12-4:
bit 1
bit 7/8
Stop bit
Word 1
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
bit 0
1 TCY
Word 1
Transmit Shift Reg
ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)
Write to TXREG
BRG Output
(Shift Clock)
Word 1
RB7/TX/CK
pin
TXIF bit
(Interrupt Reg. Flag)
Word 2
Start bit
bit 0
1 TCY
bit 1
Word 1
bit 7/8
Stop bit
Start bit
bit 0
Word 2
1 TCY
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Note:
Word 1
Transmit Shift Reg.
Word 2
Transmit Shift Reg.
This timing diagram shows two consecutive transmissions.
DS41262A-page 142
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 12-5:
Addr
Name
0Ch
PIR1
18h
RCSTA
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION(1)
Bit 7
Bit 6
Bit 5
—
ADIF
RCIF
SPEN
RX9
SREN
Bit 4
Value on
POR, BOR
Value on
all other
Resets
Bit 3
Bit 2
Bit 1
Bit 0
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
CREN
ADDEN
FERR
OERR
RX9D
0000 000X
0000 000X
0000 0000
19h
TXREG
EUSART Transmit Data Register
0000 0000
1Ah
RCREG
EUSART Receive Data Register
0000 0000
0000 0000
86h
TRISB
8Ch
PIE1
98h
TXSTA
99h
SPBRG
9Ah
9Bh
TRISB7
TRISB6
—
ADIE
CSRC
TX9
BRG7
BRG6
SPBRGH
BRG15
BAUDCTL
ABDOVF
Legend:
Note
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
-000 0000
-000 0000
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
x = unknown, - = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Transmission.
1:
PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 143
PIC16F685/687/689/690
12.3.2
EUSART ASYNCHRONOUS
RECEIVER
12.3.3
The receiver block diagram is shown in Figure 12-5.
The data is received on the RB5/AN11/RX/DT pin and
drives the data recovery block. The data recovery block
is actually a high-speed shifter operating at 16 times
the baud rate, whereas the main receive serial shifter
operates at the bit rate or at FOSC. This mode would
typically be used in RS-232 systems.
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
2. Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
3. If interrupts are required, set the RCEN bit and
select the desired priority level with the RCIP bit.
4. Set the RX9 bit to enable 9-bit reception.
5. Set the ADDEN bit to enable address detect.
6. Enable reception by setting the CREN bit.
7. The RCIF bit will be set when reception is
complete. The interrupt will be acknowledged if
the RCIE and GIE bits are set.
8. Read the RCSTA register to determine if any
error occurred during reception, as well as read
bit 9 of data (if applicable).
9. Read RCREG to determine if the device is being
addressed.
10. If any error occurred, clear the CREN bit.
11. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and interrupt the CPU.
To set up an Asynchronous Reception:
1.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set enable bit RCIE.
4. If 9-bit reception is desired, set bit RX9.
5. Enable the reception by setting bit CREN.
6. Flag bit RCIF will be set when reception is
complete and an interrupt will be generated if
enable bit RCIE was set.
7. Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
8. Read the 8-bit received data by reading the
RCREG register.
9. If any error occurred, clear the error by clearing
enable bit CREN.
10. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
FIGURE 12-5:
SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
EUSART RECEIVE BLOCK DIAGRAM
CREN
OERR
FERR
RCIDL
x64 Baud Rate CLK
BRG16
SPBRGH
SPBRG
Baud Rate Generator
÷ 64
or
÷ 16
or
÷4
RSR Register
MSb
(8)
Stop
7
• • •
1
LSb
0
Start
RX9
RB5/AN11/
RX/DT Pin
Pin Buffer
and Control
Data
Recovery
RX9D
RCREG Register
FIFO
SPEN
8
Interrupt
RCIF
Data Bus
RCIE
DS41262A-page 144
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 12-6:
ASYNCHRONOUS RECEPTION
Start
bit
bit 0
RB5/AN11/
RX/DT Pin
bit 7/8 Stop
bit
bit 1
Rcv Shift
Reg.
Rcv. Buffer Reg.
Start
bit
bit 7/8 Stop
bit
bit 0
bit 7/8
Stop
bit
Word 2
RCREG
Word 1
RCREG
RCIDL
Start
bit
Read Rcv
Buffer Reg
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN
Note:
This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
causing the OERR (overrun) bit to be set.
TABLE 12-6:
Addr
Name
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION(1)
Bit 7
Bit 6
Bit 5
—
ADIF
RCIF
SPEN
RX9
SREN
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
CREN
ADDEN
FERR
OERR
RX9D
0000 000X
0000 000X
Bit 4
0Ch
PIR1
18h
RCSTA
19h
TXREG
EUSART Transmit Data Register
0000 0000
0000 0000
1Ah
RCREG
EUSART Receive Data Register
0000 0000
0000 0000
86h
TRISB
8Ch
PIE1
98h
TXSTA
CSRC
99h
SPBRG
BRG7
9Ah
SPBRGH
BRG15
9Bh
BAUDCTL
ABDOVF
Legend:
Note
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
—
ADIE
RCIE
TXIE
SSPIE
CCPIE
TMR2IE
TMR1IE
-000 0000
-000 0000
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Reception.
1:
PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 145
PIC16F685/687/689/690
12.3.4
AUTO-WAKE-UP ON RX PIN
FALLING EDGE
The auto-wake-up feature allows the controller to
wake-up due to activity on the RX/DT line, despite the
baud clock being turned off. This allows communications
systems to save power by only responding to direct
requests.
Setting the WUE bit (BAUDCTL<1>) enables the
auto-wake-up feature. When the auto-wake-up feature
is enabled, the next falling edge on the RX/DT line will
trigger an RCIF interrupt. The WUE bit will automatically
clear after the rising RX/DT edge after triggering a falling
edge. Receiving a RCIF interrupt after setting the WUE
bit signals to the user that the wake-up event has
occurred. See Figure 12-7 and Figure 12-8 for timing
details of the auto-wake-up process.
12.3.4.1
Special care should be taken when using the
Two-Speed Start-up or the Fail-Safe Clock Monitor
because the application will start running from the
internal oscillator before the primary oscillator is ready.
Because the auto-wake-up feature uses the RCIF flag
to signify the wake-up event, the application should
discard the data read from RCREG when servicing the
RCIF flag after setting the WUE bit.
When entering Sleep with auto-wake-up enabled, the
following procedure should be used.
1.
2.
Clear all interrupt flags including RCIF.
Check RCIDL to ensure no receive is currently
in progress.
No characters are being received so the WUE
bit can be set.
Sleep.
3.
4.
Special Considerations Using
Auto-Wake-Up
The auto-wake-up function is edge sensitive. To
prevent data errors or framing errors, the data following
the Break should be all ‘0’s until the baud clock is
stable. If the LP, XT or HS oscillators are used, the
oscillator start-up time will affect the amount of time the
application must wait before receiving valid data.
FIGURE 12-7:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Auto Cleared
Bit Set by User
WUE bit
RX/DT Line
RCIF
Note:
Cleared due to User Read of RCREG
The EUSART remains in IDLE while the WUE bit is set.
FIGURE 12-8:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1Q2Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4
OSC1
Auto Cleared
Bit Set by User
WUE bit
RX/DT Line
RCIF
Cleared due to User Read of RCREG
Sleep Command Executed
DS41262A-page 146
Sleep Ends
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
12.3.5
BREAK CHARACTER SEQUENCE
The EUSART module has the capability of sending the
special Break character sequences that are required by
the LIN bus standard. The Break character transmit
consists of a Start bit, followed by 12 ‘0’ bits and a Stop
bit. The frame Break character is sent whenever the
SENB and TXEN bits (TXSTA<3> and TXSTA<5>) are
set, while the Transmit Shift register is loaded with
data. Note that the value of data written to TXREG will
be ignored and all ‘0’s will be transmitted.
The SENB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN specification).
Note that the data value written to the TXREG for the
Break character is ignored. The write simply serves the
purpose of initiating the proper sequence.
The TRMT bit indicates when the transmit operation is
active or IDLE, just as it does during normal
transmission. See Figure 12-9 for the timing of the Break
character sequence.
12.3.5.1
Break and Sync Transmit Sequence
The following sequence will send a message frame
header made up of a Break, followed by an auto-baud
Sync byte. This sequence is typical of a LIN bus
master.
1.
2.
3.
4.
5.
Configure the EUSART for the desired mode.
Set the TXEN and SENB bits to setup the Break
character.
Load the TXREG with a dummy character to
initiate transmission (the value is ignored).
Write ‘55h’ to TXREG to load the Sync character
into the transmit FIFO buffer.
After the Break has been sent, the SENB bit is
reset by hardware. The Sync character now
transmits in the Pre-Configured mode.
When the TXREG becomes empty, as indicated by the
TXIF, the next data byte can be written to TXREG.
12.3.6
RECEIVING A BREAK CHARACTER
The EUSART module can receive a Break character in
two ways.
The first method forces to configure the baud rate at a
frequency of 9/13 the typical speed. This allows for the
Stop bit transition to be at the correct sampling location
(13 bits for Break versus Start bit and 8 data bits for
typical data).
The second method uses the auto-wake-up feature
described in Section 12.3.4 “Auto-Wake-up on RX
Pin Falling Edge”. By enabling this feature, the
EUSART will sample the next two transitions on RX/DT,
cause an RCIF interrupt, and receive the next data byte
followed by another interrupt.
Note that following a Break character, the user will
typically want to enable the Auto-Baud Detect feature.
For both methods, the user can set the ABD bit before
placing the EUSART in its Sleep mode.
FIGURE 12-9:
Write to TXREG
SEND BREAK CHARACTER SEQUENCE
Dummy Write
BRG Output
(Shift Clock)
TX (pin)
Start Bit
Bit 0
Bit 1
Bit 11
Stop Bit
Break
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
SENB Sampled Here
Auto Cleared
SENB
(Transmit Shift
Reg. Empty Flag)
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 147
PIC16F685/687/689/690
12.4
EUSART Synchronous Master
Mode
Once the TXREG register transfers the data to the TSR
register (occurs in one TCYCLE), the TXREG is empty
and interrupt bit TXIF (PIR1<4>) is set. The interrupt
can be enabled/disabled by setting/clearing enable bit
TXIE (PIE1<4>). Flag bit TXIF will be set, regardless of
the state of enable bit TXIE, and cannot be cleared in
software. It will reset only when new data is loaded into
the TXREG register.
The Synchronous Master mode is entered by setting
the CSRC bit (TXSTA<7>). In this mode, the data is
transmitted in a half-duplex manner (i.e., transmission
and reception do not occur at the same time). When
transmitting data, the reception is inhibited and vice
versa. Synchronous mode is entered by setting bit
SYNC (TXSTA<4>). In addition, enable bit SPEN
(RCSTA<7>) is set in order to configure the
RB6/SCK/SCL and RB7/TX/CK or RB5/AN11/RX/DT
I/O pins to CK (clock) and DT (data) lines, respectively.
While flag bit TXIF indicates the status of the TXREG
register, another bit, TRMT (TXSTA<1>), shows the
status of the TSR register. TRMT is a read-only bit,
which is set when the TSR is empty. No interrupt logic
is tied to this bit, so the user has to poll this bit in order
to determine if the TSR register is empty. The TSR is
not mapped in data memory, so it is not available to the
user.
The Master mode indicates that the processor
transmits the master clock on the CK line. Clock
polarity is selected with the SCKP bit (BAUDCTL<4>);
setting SCKP sets the IDLE state on CK as high, while
clearing the bit, sets the IDLE state low. This option is
provided to support Microwire devices with this module.
12.4.1
To set up a Synchronous Master Transmission:
1.
EUSART SYNCHRONOUS MASTER
TRANSMISSION
2.
The EUSART transmitter block diagram is shown in
Figure 12-2. The heart of the transmitter is the Transmit
(serial) Shift Register (TSR). The shift register obtains
its data from the read/write transmit buffer register
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREG (if available).
3.
4.
5.
6.
7.
8.
FIGURE 12-10:
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set bit TX9.
Enable the transmission by setting bit TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
SYNCHRONOUS TRANSMISSION
Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4
RB5/AN11/
RX/DT pin
bit 0
RB7/
TX/CK pin
(SCKP = 0)
bit 1
Word 1
bit 2
Q3Q4 Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4
bit 7
bit 0
bit 1
Word 2
bit 7
RB7/
TX/CK pin
(SCKP = 1)
Write to
TXREG Reg
Write Word 1
Write Word 2
TXIF bit
(Interrupt Flag)
TRMT bit
TXEN bit
Note:
‘1’
‘1’
Sync Master mode, SPBRG = 0, continuous transmission of two 8-bit words.
DS41262A-page 148
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 12-11:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
RB5/AN11/RX/DT pin
bit 0
bit 2
bit 1
bit 6
bit 7
RB7/TX/CK pin
Write to
TXREG Reg
TXIF bit
TRMT bit
TXEN bit
TABLE 12-7:
Addr
Name
0Ch
PIR1
18h
RCSTA
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION(1)
Bit 7
Bit 6
Bit 5
—
ADIF
RCIF
SPEN
RX9
SREN
Bit 4
Value on
POR, BOR
Value on
all other
Resets
Bit 3
Bit 2
Bit 1
Bit 0
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
CREN
ADDEN
FERR
OERR
RX9D
0000 000X
0000 000X
19h
TXREG
EUSART Transmit Data Register
0000 0000
0000 0000
1Ah
RCREG
EUSART Receive Data Register
0000 0000
0000 0000
86h
TRISB
8Ch
PIE1
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
—
ADIE
RCIE
TXIE
SSPIE
CCPIE
TMR2IE
TMR1IE
-000 0000
98h
-000 0000
TXSTA
CSRC
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
99h
SPBRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
9Ah
SPBRGH
BRG15
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
9Bh
BAUDCTL
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
Legend:
Note
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Reception.
1:
PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 149
PIC16F685/687/689/690
12.4.2
EUSART SYNCHRONOUS MASTER
RECEPTION
3.
4.
5.
6.
Ensure bits CREN and SREN are clear.
If interrupts are desired, set enable bit RCIE.
If 9-bit reception is desired, set bit RX9.
If a single reception is required, set bit SREN.
For continuous reception, set bit CREN.
7. Interrupt flag bit RCIF will be set when reception
is complete and an interrupt will be generated if
the enable bit RCIE was set.
8. Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
10. If any error occurred, clear the error by clearing
bit CREN.
11. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
Once Synchronous mode is selected, reception is
enabled by setting either the Single Receive Enable bit
SREN (RCSTA<5>), or the Continuous Receive
Enable bit, CREN (RCSTA<4>). Data is sampled on the
RB5/AN11/RX/DT pin on the falling edge of the clock.
If enable bit SREN is set, only a single word is received.
If enable bit CREN is set, the reception is continuous
until CREN is cleared. If both bits are set, then CREN
takes precedence.
To set up a Synchronous Master Reception:
1.
2.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
FIGURE 12-12:
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Q2 Q3Q4Q1Q2Q3Q4Q1Q2 Q3Q4 Q1Q2Q3Q4Q1Q2 Q3Q4 Q1Q2Q3Q4Q1Q2Q3 Q4 Q1Q2 Q3Q4 Q1Q2Q3 Q4 Q1Q2 Q3Q4 Q1Q2Q3Q4
RB5/AN11/
RX/DT pin
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
RB7/
TX/CK pin
(SCKP = 0)
RB7/
TX/CK pin
(SCKP = 1)
Write to
bit SREN
SREN bit
CREN bit
‘0’
‘0’
RCIF bit
(Interrupt)
Read
RXREG
Note:
Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.
DS41262A-page 150
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 12-8:
Addr
Name
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION(1)
Bit 7
Bit 6
Bit 5
—
ADIF
RCIF
SPEN
RX9
SREN
0Ch
PIR1
18h
RCSTA
19h
TXREG
EUSART Transmit Data Register
1Ah
RCREG
EUSART Receive Data Register
86h
TRISB
TRISB7
TRISB6
TRISB5
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
CREN
ADDEN
FERR
OERR
RX9D
0000 000X
0000 000X
0000 0000
0000 0000
Bit 4
0000 0000
0000 0000
TRISB4
—
—
—
—
1111 ----
1111 ----
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCPIE
TMR2IE
TMR1IE
-000 0000
-000 0000
98h
TXSTA
CSRC
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
99h
SPBRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
9Ah
SPBRGH
BRG15
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
9Bh
BAUDCTL
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
Legend:
Note
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Reception.
1:
PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 151
PIC16F685/687/689/690
12.5
EUSART Synchronous Slave
Mode
To set up a Synchronous Slave Transmission:
1.
Synchronous Slave mode is entered by clearing bit
CSRC (TXSTA<7>). This mode differs from the
Synchronous Master mode in that the shift clock is
supplied externally at the RB7/TX/CK pin (instead of
being supplied internally in Master mode). This allows
the device to transfer or receive data while in any
Low-power mode.
12.5.1
Enable the synchronous slave serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
Clear bits CREN and SREN.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set bit TX9.
Enable the transmission by setting enable bit
TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Load data to TXREG register.
TXREG data will be transmitted synchronous to
the master clock.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
2.
3.
4.
5.
6.
EUSART SYNCHRONOUS SLAVE
TRANSMIT
7.
8.
The operation of the Synchronous Master and Slave
modes are identical, except in the case of the Sleep
mode.
9.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
a)
The first word will immediately transfer to the
TSR register.
The second word will remain in TXREG register.
Flag bit TXIF will not be set.
When the first word has been shifted out of TSR,
the TXREG register will transfer the second
word to the TSR and flag bit TXIF will now be
set.
If enable bit TXIE is set, the interrupt will wake
the chip from Sleep. If the global interrupt is
enabled, the program will branch to the interrupt
vector.
b)
c)
d)
e)
TABLE 12-9:
Addr
REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION(1)
Name
0Ch
PIR1
18h
RCSTA
Bit 7
Bit 6
Bit 5
—
ADIF
RCIF
SPEN
RX9
SREN
Bit 4
Value on
POR, BOR
Value on
all other
Resets
Bit 3
Bit 2
Bit 1
Bit 0
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
CREN
ADDEN
FERR
OERR
RX9D
0000 000X
0000 000X
0000 0000
19h
TXREG
EUSART Transmit Data Register
0000 0000
1Ah
RCREG
EUSART Receive Data Register
0000 0000
0000 0000
86h
TRISB
1111 ----
1111 ----
8Ch
PIE1
98h
TXSTA
TRISB7
TRISB6
—
ADIE
CSRC
TX9
TRISB5
TRISB4
—
—
—
—
RCIE
TXIE
SSPIE
CCPIE
TMR2IE
TMR1IE
-000 0000
-000 0000
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
99h
SPBRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
9Ah
SPBRGH
BRG15
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
9Bh
BAUDCTL
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
Legend:
Note
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Reception.
1:
PIC16F687/PIC16F689/PIC16F690 only.
DS41262A-page 152
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
12.5.2
EUSART SYNCHRONOUS SLAVE
RECEPTION
To set up a Synchronous Slave Reception:
1.
The operation of the Synchronous Master and Slave
modes is identical, except in the case of Sleep, or any
IDLE mode and bit SREN, which is a “don’t care” in
Slave mode.
Enable the synchronous master serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
If interrupts are desired, set enable bit RCIE.
If 9-bit reception is desired, set bit RX9.
To enable reception, set enable bit CREN.
Flag bit RCIF will be set when reception is
complete. An interrupt will be generated if
enable bit RCIE was set.
Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
Read the 8-bit received data by reading the
RCREG register.
If any error occurred, clear the error by clearing
bit CREN.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
2.
3.
4.
5.
If receive is enabled by setting the CREN bit prior to
entering Sleep, then a word may be received. Once the
word is received, the RSR register will transfer the data
to the RCREG register; if the RCIE enable bit is set, the
interrupt generated will wake the chip from Sleep. If the
global interrupt is enabled, the program will branch to
the interrupt vector.
6.
7.
8.
9.
TABLE 12-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION(1)
Addr
Name
Bit 7
Bit 6
Bit 5
—
ADIF
RCIF
SPEN
RX9
SREN
0Ch
PIR1
18h
RCSTA
19h
TXREG
EUSART Transmit Register
1Ah
RCREG
EUSART Receive Register
86h
TRISB
TRISB7
TRISB6
TRISB5
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
CREN
ADDEN
FERR
OERR
RX9D
0000 000X
0000 000X
0000 0000
0000 0000
Bit 4
0000 0000
0000 0000
TRISB4
—
—
—
—
1111 ----
1111 ----000 0000
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCPIE
TMR2IE
TMR1IE
-000 0000
98h
TXSTA
CSRC
TX9
TXEN
SYNC
SENB
BRGH
TRMT
TX9D
0000 0010
0000 0010
99h
SPBRG
BRG7
BRG6
BRG5
BRG4
BRG3
BRG2
BRG1
BRG0
0000 0000
0000 0000
9Ah
SPBRGH
BRG15
BRG14
BRG13
BRG12
BRG11
BRG10
BRG9
BRG8
0000 0000
0000 0000
9Bh
BAUDCTL
ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
01-0 0-00
01-0 0-00
Legend:
Note
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for Asynchronous Reception.
1:
PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 153
PIC16F685/687/689/690
NOTES:
DS41262A-page 154
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.0
SSP MODULE OVERVIEW
FIGURE 13-1:
The Synchronous Serial Port (SSP) module is a serial
interface used to communicate with other peripheral or
microcontroller devices. These peripheral devices may
be serial EEPROMs, shift registers, display drivers,
A/D converters, etc. The SSP module can operate in
one of two modes:
• Serial Peripheral Interface (SPI™)
• Inter-Integrated Circuit (I2C™)
Internal
Data Bus
Read
Write
SSPBUF reg
RB4/AN10/
SDI/SDA
Refer to Application Note AN578, “Use of the SSP
Module in the Multi-Master Environment” (DS00578).
13.1
SSP BLOCK DIAGRAM
(SPI MODE)
SSPSR reg
Shift
Clock
bit 0
SPI Mode
This section contains register definitions and operational
characteristics of the SPI module.
The SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. To accomplish
communication, typically three pins are used:
RC7/AN9/
SDO
Peripheral OE
SS Control
Enable
RC6/AN8/
SS
• Serial Data Out (SDO) – RC7/AN9/SDO
• Serial Data In (SDI) – RB4/AN10/SDI/SDA
• Serial Clock (SCK) – RB6/SCK/SCL
Edge
Select
2
Clock Select
Additionally, a fourth pin may be used when in a Slave
mode of operation:
SSPM<3:0>
4
• Slave Select (SS) – RC6/AN8/SS
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.
Edge
Select
RB6/SCK/
SCL
TMR2 Output
2
Prescaler TCY
4, 16, 64
TRISB<6>
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<4>
bit. The peripheral OE signal from the
SSP module into PORTC controls the
state that is read back from the TRISC<4>
bit
(see Section 17.0 “Electrical
Specifications” for information on
PORTC). If read-write-modify instructions,
such as BSF, are performed on the
TRISC register while the SS pin is high,
this will cause the TRISC<7> bit to be set,
thus disabling the SDO output.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 155
PIC16F685/687/689/690
REGISTER 13-1:
SSPSTAT – SYNC SERIAL PORT STATUS REGISTER(1) (ADDRESS: 94h)
R/W-0
R/W-0
R-0
R-0
R-0
R-0
R-0
R-0
SMP
CKE
D/A
P
S
R/W
UA
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
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
Note 1: PIC16F687/PIC16F689/PIC16F690 only.
Legend:
DS41262A-page 156
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
REGISTER 13-2:
SSPCON – SYNC SERIAL PORT CONTROL REGISTER(1) (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(2)
SSPM2(2)
SSPM1(2)
SSPM0(2)
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 “don’t 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
SSPM<3:0>: 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
1000 = Reserved
1001 = Load SSPMSK register at SSPADD SFR address(2)
1010 = Reserved
1011 = I2C Firmware Controlled Master mode (slave IDLE)
1100 = Reserved
1101 = Reserved
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
Note 1:
2:
PIC16F687/PIC16F689/PIC16F690 only.
When this mode is selected, any reads or writes to the SSPADD SFR address actually
accesses the SSPMSK register.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2005 Microchip Technology Inc.
Preliminary
x = Bit is unknown
DS41262A-page 157
PIC16F685/687/689/690
13.2
Operation
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSPCON<5:0> and SSPSTAT<7:6>).
These control bits allow the following to be specified:
•
•
•
•
Master mode (SCK is the clock output)
Slave mode (SCK is the clock input)
Clock Polarity (Idle state of SCK)
Data Input Sample Phase (middle or end of data
output time)
• Clock Edge (output data on rising/falling edge of
SCK)
• Clock Rate (Master mode only)
• Slave Select mode (Slave mode only)
The SSP consists of a transmit/receive shift register
(SSPSR) and a buffer register (SSPBUF). The SSPSR
shifts the data in and out of the device, MSb first. The
SSPBUF holds the data that was written to the SSPSR
until the received data is ready. Once the eight bits of
data have been received, that byte is moved to the
SSPBUF register. Then, the Buffer Full Status bit, BF
(SSPSTAT<0>), and the interrupt flag bit, SSPIF, are
set. This double-buffering of the received data
(SSPBUF) allows the next byte to start reception before
reading the data that was just received. Any write to the
SSPBUF register during transmission/reception of data
will be ignored and the Write Collision Detect bit,
WCOL (SSPCON<7>), will be set. User software must
clear the WCOL bit so that it can be determined if the
following write(s) to the SSPBUF register completed
successfully.
EXAMPLE 13-1:
LOOP
BSF
BCF
BTFSS
GOTO
BCF
MOVF
MOVWF
MOVF
MOVWF
The SSPSR is not directly readable or writable and can
only be accessed by addressing the SSPBUF register.
Additionally, the SSP Status register (SSPSTAT)
indicates the various status conditions.
LOADING THE SSPBUF (SSPSR) REGISTER
STATUS,RP0
STATUS,RP1
SSPSTAT, BF
LOOP
STATUS,RP0
SSPBUF, W
RXDATA
TXDATA, W
SSPBUF
DS41262A-page 158
When the application software is expecting to receive
valid data, the SSPBUF should be read before the next
byte of data to transfer is written to the SSPBUF. Buffer
Full bit, BF (SSPSTAT<0>), indicates when SSPBUF
has been loaded with the received data (transmission
is complete). When the SSPBUF is read, the BF bit is
cleared. This data may be irrelevant if the SPI is only a
transmitter. Generally, the SSP interrupt is used to
determine when the transmission/reception has
completed. The SSPBUF must be read and/or written.
If the interrupt method is not going to be used, then
software polling can be done to ensure that a write
collision does not occur. Example 13-1 shows the
loading of the SSPBUF (SSPSR) for data transmission.
;Bank 1
;
;Has data been received(transmit complete)?
;No
;Bank 0
;WREG reg = contents of SSPBUF
;Save in user RAM, if data is meaningful
;W reg = contents of TXDATA
;New data to xmit
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.3
Enabling SPI I/O
13.4
To enable the serial port, SSP Enable bit, SSPEN
(SSPCON<5>), must be set. To reset or reconfigure
SPI mode, clear the SSPEN bit, re-initialize the
SSPCON registers and then set the SSPEN bit. This
configures the SDI, SDO, SCK and SS pins as serial
port pins. For the pins to behave as the serial port
function, some must have their data direction bits (in
the TRISB and TRISC registers) appropriately
programmed. That is:
• SDI is automatically controlled by the SPI module
• SDO must have TRISC<7> bit cleared
• SCK (Master mode) must have TRISB<6> bit
cleared
• SCK (Slave mode) must have TRISB<6> bit set
• SS must have TRISC<6> bit set
Typical Connection
Figure 13-2 shows a typical connection between two
microcontrollers. The master controller (Processor 1)
initiates the data transfer by sending the SCK signal.
Data is shifted out of both shift registers on their
programmed clock edge and latched on the opposite
edge of the clock. Both processors should be
programmed to the same Clock Polarity (CKP), then
both controllers would send and receive data at the
same time. Whether the data is meaningful (or dummy
data) depends on the application software. This leads
to three scenarios for data transmission:
• Master sends data – Slave sends dummy data
• Master sends data – Slave sends data
• Master sends dummy data – Slave sends data
Any serial port function that is not desired may be
overridden by programming the corresponding data
direction (TRISB and TRISC) registers to the opposite
value.
FIGURE 13-2:
SPI™ MASTER/SLAVE CONNECTION
SPI™ Master SSPM<3:0> = 00xxb
SPI™ Slave SSPM<3:0> = 010xb
SDO
SDI
Serial Input Buffer
(SSPBUF)
SDI
Shift Register
(SSPSR)
MSb
Serial Input Buffer
(SSPBUF)
SDO
LSb
MSb
SCK
Serial Clock
Processor 1
© 2005 Microchip Technology Inc.
Shift Register
(SSPSR)
LSb
SCK
Processor 2
Preliminary
DS41262A-page 159
PIC16F685/687/689/690
13.5
Master Mode
The master can initiate the data transfer at any time
because it controls the SCK. The master determines
when the slave (Processor 2, Figure 13-2) is to
broadcast data by the software protocol.
In Master mode, the data is transmitted/received as
soon as the SSPBUF register is written to. If the SPI is
only going to receive, the SDO output could be
disabled (programmed as an input). The SSPSR
register will continue to shift in the signal present on the
SDI pin at the programmed clock rate. As each byte is
received, it will be loaded into the SSPBUF register as
if a normal received byte (interrupts and Status bits
appropriately set). This could be useful in receiver
applications as a “Line Activity Monitor” mode.
FIGURE 13-3:
The clock polarity is selected by appropriately
programming the CKP bit (SSPCON<4>). This then,
would give waveforms for SPI communication as shown
in Figure 13-3, Figure 13-5 and Figure 13-6, where the
MSB is transmitted first. In Master mode, the SPI clock
rate (bit rate) is user programmable to be one of the
following:
•
•
•
•
FOSC/4 (or TCY)
FOSC/16 (or 4 • TCY)
FOSC/64 (or 16 • TCY)
Timer2 output/2
This allows a maximum data rate (at 40 MHz) of
10 Mbps.
Figure 13-3 shows the waveforms for Master mode.
When the CKE bit is set, the SDO data is valid before
there is a clock edge on SCK. The change of the input
sample is shown based on the state of the SMP bit. The
time when the SSPBUF is loaded with the received
data is shown.
SPI™ MODE WAVEFORM (MASTER MODE)
Write to
SSPBUF
SCK
(CKP = 0
CKE = 0)
SCK
(CKP = 1
CKE = 0)
4 Clock
Modes
SCK
(CKP = 0
CKE = 1)
SCK
(CKP = 1
CKE = 1)
SDO
(CKE = 0)
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SDO
(CKE = 1)
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SDI
(SMP = 0)
bit 0
bit 7
Input
Sample
(SMP = 0)
SDI
(SMP = 1)
bit 0
bit 7
Input
Sample
(SMP = 1)
SSPIF
Next Q4 Cycle
after Q2↓
SSPSR to
SSPBUF
DS41262A-page 160
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.6
Slave Mode
In Slave mode, the data is transmitted and received as
the external clock pulses appear on SCK. When the
last bit is latched, the SSPIF interrupt flag bit is set.
While in Slave mode, the external clock is supplied by
the external clock source on the SCK pin. This external
clock must meet the minimum high and low times as
specified in the electrical specifications.
While in Sleep mode, the slave can transmit/receive
data. When a byte is received, the device will wake-up
from Sleep.
13.7
Slave Select Synchronization
The SS pin allows a Synchronous Slave mode. The SPI
must be in Slave mode with SS pin control enabled
(SSPCON<3:0> = 04h). The pin must not be driven low
for the SS pin to function as an input. The data latch
must be high. When the SS pin is low, transmission and
reception are enabled and the SDO pin is driven. When
the SS pin goes high, the SDO pin is no longer driven,
FIGURE 13-4:
even if in the middle of a transmitted byte, and becomes
a floating output. External pull-up/pull-down resistors
may be desirable, depending on the application.
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
set, then the SS pin control must be
enabled.
When the SPI module resets, the bit counter is forced
to ‘0’. This can be done by either forcing the SS pin to
a high level or clearing the SSPEN bit.
To emulate two-wire communication, the SDO pin can
be connected to the SDI pin. When the SPI needs to
operate as a receiver, the SDO pin can be configured
as an input. This disables transmissions from the SDO.
The SDI can always be left as an input (SDI function)
since it cannot create a bus conflict.
SLAVE SYNCHRONIZATION WAVEFORM
SS
SCK
(CKP = 0
CKE = 0)
SCK
(CKP = 1
CKE = 0)
Write to
SSPBUF
SDO
SDI
(SMP = 0)
bit 7
bit 6
bit 7
bit 0
bit 0
bit 7
bit 7
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
SSPSR to
SSPBUF
© 2005 Microchip Technology Inc.
Next Q4 Cycle
after Q2↓
Preliminary
DS41262A-page 161
PIC16F685/687/689/690
FIGURE 13-5:
SPI™ MODE WAVEFORM (SLAVE MODE WITH CKE = 0)
SS
Optional
SCK
(CKP = 0
CKE = 0)
SCK
(CKP = 1
CKE = 0)
Write to
SSPBUF
SDO
bit 7
SDI
(SMP = 0)
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
bit 0
bit 7
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
Next Q4 Cycle
after Q2↓
SSPSR to
SSPBUF
FIGURE 13-6:
SPI™ MODE WAVEFORM (SLAVE MODE WITH CKE = 1)
SS
Not Optional
SCK
(CKP = 0
CKE = 1)
SCK
(CKP = 1
CKE = 1)
Write to
SSPBUF
SDO
SDI
(SMP = 0)
bit 6
bit 7
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
bit 0
bit 7
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
Next Q4 Cycle
after Q2↓
SSPSR to
SSPBUF
DS41262A-page 162
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.8
Sleep Operation
13.10 Bus Mode Compatibility
In Master mode, all module clocks are halted and the
transmission/reception will remain in that state until the
device wakes from Sleep. After the device returns to
normal mode, the module will continue to transmit/receive
data.
Table 13-1 shows the compatibility between the
standard SPI modes and the states of the CKP and
CKE control bits.
TABLE 13-1:
In Slave mode, the SPI Transmit/Receive Shift register
operates asynchronously to the device. This allows the
device to be placed in Sleep mode and data to be
shifted into the SPI Transmit/Receive Shift register.
When all 8 bits have been received, the SSP interrupt
flag bit will be set and if enabled, will wake the device
from Sleep.
13.9
Effects of a Reset
Control Bits State
Standard SPI™
Mode Terminology
CKP
CKE
0, 0
0
1
0, 1
0
0
1, 0
1
1
1, 1
1
0
There is also a SMP bit which controls when the data is
sampled.
A Reset disables the SSP module and terminates the
current transfer.
TABLE 13-2:
SPI™ BUS MODES
REGISTERS ASSOCIATED WITH SPI™ OPERATION(1)
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR,
BOR
Value on
all other
Resets
0Bh/8Bh/
INTCON
10Bh/18Bh
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
—
ADIF
RCIF
TXIF
SSPIF
Address
CCP1IF TMR2IF TMR1IF
-000 0000
-000 0000
xxxx xxxx
uuuu uuuu
SSPM0
0000 0000
0000 0000
—
1111 ----
1111 ----
0Ch
PIR1
13h
SSPBUF
14h
SSPCON
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
86h/186h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
87h/187h
TRISC
TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
8Ch
PIE1
94h
SSPSTAT
Legend:
Note
Synchronous Serial Port Receive Buffer/Transmit Register
—
ADIE
RCIE
TXIE
SSPIE
SMP
CKE
D/A
P
S
CCP1IE TMR2IE TMR1IE
R/W
UA
BF
1111 1111
1111 1111
-000 0000
-000 0000
0000 0000
0000 0000
x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by the SSP in SPI mode.
1:
PIC16F687/PIC16F689/PIC16F690 only.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 163
PIC16F685/687/689/690
13.11 SSP I2C 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 facilitate
firmware implementations of the master functions. The
SSP module implements the standard mode
specifications, as well as 7-bit and 10-bit addressing.
Two pins are used for data transfer. These are the
RB6/SCK/SCL pin, which is the clock (SCL), and the
RB4/AN10/SDI/SDA pin, which is the data (SDA).
The SSP module functions are enabled by setting SSP
enable bit SSPEN (SSPCON<5>).
FIGURE 13-7:
Internal
Data Bus
Read
Write
SSPBUF reg
13.12 Slave Mode
SSPSR reg
In Slave mode, the SCL and SDA pins must be
configured as inputs (TRISB<6,4> are set). The SSP
module will override the input state with the output data
when required (slave-transmitter).
Shift
Clock
RB4/
AN10/
SDI/SDA
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,
provided these pins are programmed to inputs by
setting the appropriate TRISB bits. Pull-up resistors
must be provided externally to the SCL and SDA pins
for proper operation of the I2C module.
SSP BLOCK DIAGRAM
(I2C™ MODE)
RB6/
SCK/
SCL
The SSPCON register allows control of the I2C
operation. Four mode selection bits (SSPCON<3:0>)
allow one of the following I2C modes to be selected:
MSb
LSb
Match Detect
Addr Match
SSPMSK reg
When an address is matched, or the data transfer after
an address match is received, the hardware
automatically 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):
SSPADD reg
a)
Start and
Stop bit Detect
Set, Reset
S, P bits
(SSPSTAT reg)
The SSP module has six registers for the I2C operation,
which are listed below.
•
•
•
•
SSP Control register (SSPCON)
SSP Status register (SSPSTAT)
Serial Receive/Transmit Buffer (SSPBUF)
SSP Shift register (SSPSR) – Not directly
accessible
• SSP Address register (SSPADD)
• SSP Mask register (SSPMSK)
DS41262A-page 164
b)
The buffer full bit BF (SSPSTAT<0>) was set
before the transfer was received.
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 13-3 shows the results of 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
condition. Flag bit BF is cleared by reading the
SSPBUF register, while bit SSPOV is cleared through
software.
The SCL clock input must have a minimum high and low
for proper operation. For high and low times of the I2C
specification, as well as the requirements of the SSP
module, see Section 17.0 “Electrical Specifications”.
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.12.1
ADDRESSING
Once the SSP module has been enabled, it waits for a
Start condition to occur. Following the Start condition,
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)
b)
c)
d)
The SSPSR register value is loaded into the
SSPBUF register.
The buffer full bit, BF is set.
An ACK pulse is generated.
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 13-8). The five Most
Significant 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
second 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.
TABLE 13-3:
The sequence of events for 10-bit address is as
follows, with steps 7-9 for slave-transmitter:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Receive first (high) byte of address (bits SSPIF,
BF and bit UA (SSPSTAT<1>) are set).
Update the SSPADD register with second (low)
byte of address (clears bit UA and releases the
SCL line).
Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
Receive second (low) byte of address (bits
SSPIF, BF and UA are set).
Update the SSPADD register with the first (high)
byte of address; if match releases SCL line, this
will clear bit UA.
Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
Receive repeated Start condition.
Receive first (high) byte of address (bits SSPIF
and BF are set).
Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
DATA TRANSFER RECEIVED BYTE ACTIONS
Status Bits as Data
Transfer is Received
SSPSR → SSPBUF
Generate ACK
Pulse
Set bit SSPIF
(SSP Interrupt occurs
if enabled)
BF
SSPOV
0
0
Yes
Yes
Yes
1
0
No
No
Yes
1
1
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.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 165
PIC16F685/687/689/690
13.12.2
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 user’s firmware.
An SSP interrupt is generated for each data transfer
byte. Flag bit SSPIF (PIR1<3>) must be cleared in
software. The SSPSTAT register is used to determine
the status of the byte.
I2C™ WAVEFORMS FOR RECEPTION (7-BIT ADDRESS)
FIGURE 13-8:
R/W = 0
Receiving Address
SCL
S
1
2
3
SSPIF (PIR1<3>)
BF (SSPSTAT<0>)
4
5
6
Receiving Data
ACK
A7 A6 A5 A4 A3 A2 A1
SDA
7
ACK
D7 D6 D5 D4 D3 D2 D1 D0
8
9
1
2
3
4
5
6
7
8
9
Receiving Data
ACK
D7 D6 D5 D4 D3 D2 D1 D0
1
2
3
4
5
6
7
8
Cleared in software
9
P
Bus Master
terminates
transfer
SSPBUF register is read
SSPOV (SSPCON<6>)
Bit SSPOV is set because the SSPBUF register is still full.
ACK is not sent.
DS41262A-page 166
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.12.3
SSP MASK REGISTER
2
An SSP Mask (SSPMSK) register is available in I C
Slave mode as a mask for the value held in the
SSPSR register during an address comparison
operation. A zero (‘0’) bit in the SSPMSK register has
the effect of making the corresponding bit in the
SSPSR register a ‘don’t care’.
This register is reset to all ‘1’s upon any Reset
condition and, therefore, has no effect on standard
SSP operation until written with a mask value.
REGISTER 13-3:
This register must be initiated prior to setting
SSPM<3:0> bits to select the I2C Slave mode (7-bit or
10-bit address).
This register can only be accessed when the appropriate
mode is selected by bits (SSPM<3:0> of SSPCON).
The SSP Mask register is active during:
• 7-bit Address Mode: address compare of A<7:1>.
• 10-bit Address Mode: address compare of A<7:0>
only. The SSP mask has no effect during the
reception of the first (high) byte of the address.
SSPMSK – SSP MASK REGISTER(1) (ADDRESS: 93h)
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
MSK7
MSK6
MSK5
MSK4
MSK3
MSK2
MSK1
MSK0(2)
bit 7
bit 0
bit 7-1
MSK<7:1>: Mask bits
1 = The received address bit n is compared to SSPADD<n> to detect I2C address match
0 = The received address bit n is not used to detect I2C address match
bit 0
MSK<0>: Mask bit for I2C Slave Mode, 10-bit Address(2)
I2C Slave Mode, 10-bit Address (SSPM<3:0> = 0111):
1 = The received address bit 0 is compared to SSPADD<0> to detect I2C address match
0 = The received address bit 0 is not used to detect I2C address match
Note 1: When SSPCON bits SSPM<3:0> = 1001, any reads or writes to the SSPADD SFR
address are accessed through the SSPMSK register.
2: In all other SSP modes, this bit has no effect.
Legend:
13.12.4
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
HALT ON ADDRESS DETECT
In some applications it is necessary to acknowledge
multiple addresses or blocks of addresses. The
Halt-on-Address-Detect feature allows software to
check the address and perform validation.
© 2005 Microchip Technology Inc.
x = Bit is unknown
Address Detect is enabled when the ADDEN bit of
SSPCON1 register is set to ‘1’. The SSPIF flag and
the CLKSTR bit are both set after the A1 (last bit of
address) is clocked into the SSPSR and loaded into
the SSPBUF, but before the address comparator result
is read or the ACK pulse is generated. This allows the
software to read the SSPBUF and validate the
received address. If the address is determined to be
valid, the software will copy the SSPBUF into
SSPADD, thus setting the result of the comparator to
true. The CLKSTR is then cleared (‘0’ written) the SSP
engine is allowed to continue. Since the address
compare is now true, an ACK pulse will be generated
back to the master. If the software decides that the
address is not to be acknowledged, the SSPADD is
written with any value not equal to SSPBUF. This will
set the compare to false and an ACK will be
suppressed when CLKSTR is cleared.
Preliminary
DS41262A-page 167
DS41262A-page 168
3
Preliminary
5
6
8
UA is set indicating
that the SSPADD needs to
be updated
9
(CKP does not reset to ‘0’ when SEN = 0)
UA (SSPSTAT<1>)
7
SSPBUF is written
with contents of SSPSR
SSPOV (SSPCON<6>)
CKP
4
Cleared in software
BF (SSPSTAT<0>)
(PIR1<3>)
SSPIF
2
1
SCL
S
SDA
2
4
5
6
7
Cleared in software
3
8
UA is set indicating
that SSPADD needs to
be updated
Cleared by hardware
when SSPADD is updated
with low byte of address
Dummy read of SSPBUF
to clear BF flag
1
9
Receive Second Byte of Address
ACK
A7 A6 A5 A4 A3 A2 A1 A0
1
4
5
6
7
Cleared in software
3
8
Cleared by hardware when
SSPADD is updated with high
byte of address
2
D7 D6 D5 D4 D3 D2 D1 D0
Receive Data Byte
Clock is held low until
update of SSPADD has
taken place
9
ACK
1
2
4
5
6
7
Cleared in software
3
8
D7 D6 D5 D4 D3 D2 D1 D0
Receive Data Byte
P
Bus master
terminates
transfer
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
9
ACK
FIGURE 13-9:
Receive First Byte of Address
R/W = 0
ACK
1 1 1 1 0 A9 A8 0
Clock is held low until
update of SSPADD has
taken place
PIC16F685/687/689/690
I2C™ SLAVE MODE TIMING (RECEPTION, 10-BIT ADDRESS)
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.12.5
TRANSMISSION
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.
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 RB6/SCK/SCL is held
low. The transmit data must be loaded into the
SSPBUF register, which also loads the SSPSR
register. Then, pin RB6/SCK/SCL should be enabled
by setting 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 stretching 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 13-10).
FIGURE 13-10:
I2C™ WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)
Receiving Address
SDA
SCL
A7
S
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
occurrence of the Start bit. If the SDA line was low
(ACK), the transmit data must be loaded into the
SSPBUF register, which also loads the SSPSR
register. Then pin RB6/SCK/SCL should be enabled by
setting bit CKP.
A6
1
2
Data in
sampled
R/W = 1
A5
A4
A3
A2
A1
3
4
5
6
7
8
9
ACK
Transmitting Data
ACK
D7
1
SCL held low
while CPU
responds to SSPIF
D6
D5
D4
D3
D2
D1
D0
2
3
4
5
6
7
8
9
P
Cleared in software
SSPIF (PIR1<3>)
BF (SSPSTAT<0>)
SSPBUF is written in software
From SSP Interrupt
Service Routine
CKP (SSPCON<4>)
Set bit after writing to SSPBUF
(the SSPBUF must be written to
before the CKP bit can be set)
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 169
DS41262A-page 170
1
3
Preliminary
5
6
8
UA is set indicating
that the SSPADD needs to
be updated
9
(CKP does not reset to ‘0’ when SEN = 0)
UA (SSPSTAT<1>)
7
SSPBUF is written
with contents of SSPSR
SSPOV (SSPCON<6>)
CKP
4
Cleared in software
2
BF (SSPSTAT<0>)
(PIR1<3>)
SSPIF
S
2
4
5
6
7
Cleared in software
3
8
UA is set indicating
that SSPADD needs to
be updated
Cleared by hardware
when SSPADD is updated
with low byte of address
Dummy read of SSPBUF
to clear BF flag
1
9
1
4
5
6
7
Cleared in software
3
8
Cleared by hardware when
SSPADD is updated with high
byte of address
2
9
1
2
4
5
6
7
Cleared in software
3
8
P
Bus master
terminates
transfer
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
9
FIGURE 13-11:
SCL
SDA
Clock is held low until
Clock is held low until
update of SSPADD has
update of SSPADD has
taken place
taken place
R/W
=
0
Receive
Second
Byte
of
Address
Receive First Byte of Address
Receive Data Byte
Receive Data Byte
ACK
ACK
ACK
ACK
A7 A6 A5 A4 A3 A2 A1 A0
D7 D6 D5 D4 D3 D2 D1 D0
1 1 1 1 0 A9 A8 0
D7 D6 D5 D4 D3 D2 D1 D0
PIC16F685/687/689/690
I2C™ SLAVE MODE TIMING (TRANSMISSION, 10-BIT ADDRESS)
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
13.13 Master Mode
13.14 Multi-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 conditions. 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 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 Master mode, the SCL and SDA lines are
manipulated
by
clearing
the
corresponding
TRISB<6,4> bit(s). The output level is always low,
irrespective of the value(s) in PORTB<6,4>. So when
transmitting data, a ‘1’ data bit must have the
TRISB<4> bit set (input) and a ‘0’ data bit must have
the TRISB<4> bit cleared (output). The same scenario
is true for the SCL line with the TRISB<6> bit. Pull-up
resistors must be provided externally to the SCL and
SDA pins for proper operation of the I2C module.
The following events will cause the 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 (SSPM<3:0> = 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.
© 2005 Microchip Technology Inc.
In Multi-Master operation, the SDA line must be
monitored 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 TRISB<6,4>). 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
transfer stage, communication to the device may be in
progress. If addressed, an ACK pulse will be generated.
If arbitration was lost during the data transfer stage, the
device will need to re-transfer the data at a later time.
13.14.1
CLOCK SYNCHRONIZATION AND
THE CKP BIT
When the CKP bit is cleared, the SCL output is forced
to ‘0’; however, setting the CKP bit will not assert the
SCL output low until the SCL output is already sampled
low. Therefore, the CKP bit will not assert the SCL line
until an external I2C master device has already
asserted the SCL line. The SCL output will remain low
until the CKP bit is set and all other devices on the I2C
bus have deasserted SCL. This ensures that a write to
the CKP bit will not violate the minimum high time
requirement for SCL (see Figure 13-12).
Preliminary
DS41262A-page 171
PIC16F685/687/689/690
FIGURE 13-12:
CLOCK SYNCHRONIZATION TIMING
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SDA
DX
DX-1
SCL
Master device
asserts clock
CKP
Master device
deasserts clock
WR
SSPCON
TABLE 13-4:
Addr
REGISTERS ASSOCIATED WITH I2C™ OPERATION(1)
Value on
all other
Resets
Value on
POR, BOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0Bh/8Bh/
INTCON
10Bh/18Bh
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
-000 0000
0Ch
PIR1
13h
SSPBUF
14h
SSPCON
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
0000 0000
0000 0000
86h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
—
—
—
—
1111 ----
1111 ----
93h
SSPMSK(2)
MSK7
MSK6
MSK5
MSK4
MSK3
MSK2
MSK1
MSK0
94h
SSPSTAT
SMP(3)
CKE(3)
D/A
P
S
R/W
UA
BF
0000 0000
0000 0000
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IF
TMR1IF
-000 0000
-000 0000
Legend:
Note 1:
2:
3:
Synchronous Serial Port Receive Buffer/Transmit Register
xxxx xxxx
1111 1111
uuuu uuuu
1111 1111
– = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the SSP module.
PIC16F687/PIC16F689/PIC16F690 only.
SSPMSK register (Register 13-3) can be accessed by reading or writing to SSPADD register with bits SSPM<3:0> = 1001.
See Registers 13-2 and 13-3 for more details.
Maintain these bits clear.
DS41262A-page 172
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
14.0
SPECIAL FEATURES OF THE
CPU
The PIC16F685/687/689/690 have a host of features
intended to maximize system reliability, minimize cost
through elimination of external components, provide
power saving features and offer code protection.
These features are:
• Reset
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• Oscillator selection
• Sleep
• Code protection
• ID Locations
• In-Circuit Serial Programming
The PIC16F685/687/689/690 have two timers that offer
necessary delays on power-up. One is the Oscillator
Start-up Timer (OST), intended to keep the chip in
Reset until the crystal oscillator is stable. The other is
the Power-up Timer (PWRT), which provides a fixed
delay of 64 ms (nominal) on power-up only, designed to
keep the part in Reset while the power supply
stabilizes. There is also circuitry to reset the device if a
brown-out occurs, which can use the Power-up Timer
to provide at least a 64 ms Reset. With these three
functions-on-chip, most applications need no external
Reset circuitry.
The Sleep mode is designed to offer a very low-current
Power-down mode. The user can wake-up from Sleep
through:
• External Reset
• Watchdog Timer Wake-up
• An interrupt
Several oscillator options are also made available to
allow the part to fit the application. The INTOSC option
saves system cost while the LP crystal option saves
power. A set of configuration bits are used to select
various options (see Register 14-1).
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 173
PIC16F685/687/689/690
14.1
Configuration Bits
Note:
The configuration bits can be programmed (read as
‘0’), or left unprogrammed (read as ‘1’) to select various
device configurations as shown in Register 14-1.
These bits are mapped in program memory location
2007h.
REGISTER 14-1:
Address 2007h is beyond the user program
memory space. It belongs to the special
configuration memory space (2000h3FFFh), which can be accessed only during
programming. See “PIC12F6XX/16F6XX
Memory
Programming
Specification”
(DS41204) for more information.
CONFIG – CONFIGURATION WORD (ADDRESS: 2007h)
Reserved Reserved FCMEN IESO BOREN1(1) BOREN0(1) CPD(2)
CP(3) MCLRE(4) PWRTE WDTE FOSC2 FOSC1 FOSC0
bit 13
bit 0
bit 13-12
Reserved: Reserved bits. Do Not Use.
bit 11
FCMEN: Fail-Safe Clock Monitor Enabled bit
1 = Fail-Safe Clock Monitor is enabled
0 = Fail-Safe Clock Monitor is disabled
bit 10
IESO: Internal External Switchover bit
1 = Internal External Switchover mode is enabled
0 = Internal External Switchover mode is disabled
bit 9-8
BOREN<1:0>: Brown-out Reset Selection bits(1)
11 = BOR enabled
10 = BOR enabled during operation and disabled in Sleep
01 = BOR controlled by SBOREN bit (PCON<4>)
00 = BOR disabled
bit 7
CPD: Data Code Protection bit(2)
1 = Data memory code protection is disabled
0 = Data memory code protection is enabled
bit 6
CP: Code Protection bit(3)
1 = Program memory code protection is disabled
0 = Program memory code protection is enabled
bit 5
MCLRE: RA3/MCLR/VPP pin function select bit(4)
1 = RA3/MCLR/VPP pin function is MCLR
0 = RA3/MCLR/VPP pin function is digital input, MCLR internally tied to VDD
bit 4
PWRTE: Power-up Timer Enable bit
1 = PWRT disabled
0 = PWRT enabled
bit 3
WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled and can be enabled by SWDTEN bit (WDTCON<0>)
bit 2-0
FOSC<2:0>: Oscillator Selection bits
111 = RC oscillator: CLKOUT function on RA4/AN3/T1G/OSC2/CLKOUT pin, RC on RA5/T1CKI/OSC1/CLKIN
110 = RCIO oscillator: I/O function on RA4/AN3/T1G/OSC2/CLKOUT pin, RC on RA5/T1CKI/OSC1/CLKIN
101 = INTOSC oscillator: CLKOUT function on RA4/AN3/T1G/OSC2/CLKOUT pin, I/O function on
RA5/T1CKI/OSC1/CLKIN
100 = INTOSCIO oscillator: I/O function on RA4/AN3/T1G/OSC2/CLKOUT pin, I/O function on
RA5/T1CKI/OSC1/CLKIN
011 = EC: I/O function on RA4/AN3/T1G/OSC2/CLKOUT pin, CLKIN on RA5/T1CKI/OSC1/CLKIN
010 = HS oscillator: High-speed crystal/resonator on RA4/AN3/T1G/OSC2/CLKOUT and RA5/T1CKI/OSC1/CLKIN
001 = XT oscillator: Crystal/resonator on RA4/AN3/T1G/OSC2/CLKOUT and RA5/T1CKI/OSC1/CLKIN
000 = LP oscillator: Low-power crystal on RA4/AN3/T1G/OSC2/CLKOUT and RA5/T1CKI/OSC1/CLKIN
Note
1:
2:
3:
4:
Enabling Brown-out Reset does not automatically enable Power-up Timer.
The entire data EEPROM will be erased when the code-protect is turned off.
The entire program memory will be erased when non code-protect is turned off.
When MCLR is asserted in INTOSC or RC mode, the internal clock oscillator is disabled.
Legend:
R = Readable
-n = Value at POR
DS41262A-page 174
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
Preliminary
x = Bit is unknown
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
14.2
Reset
The PIC16F685/687/689/690 differentiates between
various kinds of Reset:
a)
b)
c)
d)
e)
f)
Power-on Reset (POR)
WDT Reset during normal operation
WDT Reset during Sleep
MCLR Reset during normal operation
MCLR Reset during Sleep
Brown-out Reset (BOR)
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 14-1.
Some registers are not affected in any Reset condition;
their status is unknown on POR and unchanged in any
other Reset. Most other registers are reset to a “Reset
state” on:
•
•
•
•
•
They are not affected by a WDT wake-up since this is
viewed as the resumption of normal operation. TO and
PD bits are set or cleared differently in different Reset
situations, as indicated in Table 14-2. These bits are
used in software to determine the nature of the Reset.
See Table 14-4 for a full description of Reset states of
all registers.
The MCLR Reset path has a noise filter to detect and
ignore small pulses. See Section 17.0 “Electrical
Specifications” for pulse-width specifications.
Power-on Reset
MCLR Reset
MCLR Reset during Sleep
WDT Reset
Brown-out Reset (BOR)
FIGURE 14-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External
Reset
MCLR/VPP pin
Sleep
WDT
Module
WDT
Time-out
Reset
VDD Rise
Detect
Power-on Reset
VDD
Brown-out(1)
Reset
BOREN
SBOREN
S
OST/PWRT
OST
Chip_Reset
10-bit Ripple Counter
R
Q
OSC1/
CLKI pin
PWRT
LFINTOSC
11-bit Ripple Counter
Enable PWRT
Enable OST
Note
1:
Refer to the Configuration Word register (Register 14-1).
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 175
PIC16F685/687/689/690
14.2.1
POWER-ON RESET (POR)
14.2.3
The on-chip POR circuit holds the chip in Reset until VDD
has reached a high enough level for proper operation. A
maximum rise time for VDD is required. See
Section 17.0 “Electrical Specifications” for details. If
the BOR is enabled, the maximum rise time specification
does not apply. The BOR circuitry will keep the device in
Reset until VDD reaches VBOR (see Section 14.2.4
“Brown-Out Reset (BOR)”).
Note:
The POR circuit does not produce an
internal Reset when VDD declines. To
re-enable the POR, VDD must reach Vss
for a minimum of 100 μs.
When the device starts normal operation (exits the
Reset condition), device operating parameters (i.e.,
voltage, frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not met, the
device must be held in Reset until the operating
conditions are met.
POWER-UP TIMER (PWRT)
The Power-up Timer provides a fixed 64 ms (nominal)
time-out on power-up only, from POR or Brown-out
Reset. The Power-up Timer operates from the 31 kHz
LFINTOSC oscillator. For more information, see
Section 3.4 “Internal Clock Modes”. The chip is kept
in Reset as long as PWRT is active. The PWRT delay
allows the VDD to rise to an acceptable level. A
configuration bit, PWRTE, can disable (if set) or enable
(if cleared or programmed) the Power-up Timer. The
Power-up Timer should be enabled when Brown-out
Reset is enabled, although it is not required.
The Power-up Timer delay will vary from chip-to-chip
and vary due to:
• VDD variation
• Temperature variation
• Process variation
See DC parameters for details (Section 17.0 “Electrical
Specifications”).
For additional information, refer to Application Note
AN607, “Power-up Trouble Shooting” (DS00607).
14.2.2
MCLR
PIC16F685/687/689/690 has a noise filter in the MCLR
Reset path. The filter will detect and ignore small
pulses.
It should be noted that a WDT Reset does not drive
MCLR pin low.
The behavior of the ESD protection on the MCLR pin
has been altered from early devices of this family.
Voltages applied to the pin that exceed its specification
can result in both MCLR Resets and excessive current
beyond the device specification during the ESD event.
For this reason, Microchip recommends that the MCLR
pin no longer be tied directly to VDD. The use of an RC
network, as shown in Figure 14-2, is suggested.
An internal MCLR option is enabled by clearing the
MCLRE bit in the Configuration Word register. When
MCLRE = 0, the Reset signal to the chip is generated
internally. When the MCLRE = 1, the RA3/MCLR pin
becomes an external Reset input. In this mode, the
RA3/MCLR pin has a weak pull-up to VDD.
DS41262A-page 176
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
14.2.4
BROWN-OUT RESET (BOR)
On any Reset (Power-on, Brown-out Reset, Watchdog
Timer, etc.), the chip will remain in Reset until VDD rises
above VBOR (see Figure 14-2). The Power-up Timer
will now be invoked, if enabled and will keep the chip in
Reset an additional 64 ms.
The BOREN0 and BOREN1 bits in the Configuration
Word register select one of four BOR modes. Two
modes have been added to allow software or hardware
control of the BOR enable. When BOREN<1:0> = 01,
the SBOREN bit (PCON<4>) enables/disables the
BOR allowing it to be controlled in software. By
selecting BOREN<1:0>, the BOR is automatically
disabled in Sleep to conserve power and enabled on
wake-up. In this mode, the SBOREN bit is disabled.
See Register 14-1 for the Configuration Word
definition.
Note:
If VDD drops below VBOR while the Power-up Timer is
running, the chip will go back into a Brown-out Reset
and the Power-up Timer will be re-initialized. Once VDD
rises above VBOR, the Power-up Timer will execute a
64 ms Reset.
If VDD falls below VBOR for greater than parameter
(TBOR) (see Section 17.0 “Electrical Specifications”),
the Brown-out situation will reset the device. This will
occur regardless of VDD slew rate. A Reset is not insured
to occur if VDD falls below VBOR for less than parameter
(TBOR).
FIGURE 14-2:
BROWN-OUT SITUATIONS
VDD
Internal
Reset
VBOR
64 ms(1)
VDD
Internal
Reset
VBOR
< 64 ms
64 ms(1)
VDD
VBOR
Internal
Reset
Note 1:
The Power-up Timer is enabled by the
PWRTE bit in the Configuration Word
register.
64 ms(1)
64 ms delay only if PWRTE bit is programmed to ‘0’.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 177
PIC16F685/687/689/690
14.2.5
TIME-OUT SEQUENCE
14.2.6
On power-up, the time-out sequence is as follows: first,
PWRT time-out is invoked after POR has expired, then
OST is activated after the PWRT time-out has expired.
The total time-out will vary based on oscillator
configuration and PWRTE bit status. For example, in
EC mode with PWRTE bit erased (PWRT disabled),
there will be no time-out at all. Figures 14-3, 14-4
and 14-5 depict time-out sequences. The device can
execute code from the INTOSC while OST is active by
enabling Two-Speed Start-up or Fail-Safe Monitor (see
Section 3.6.2 “Two-Speed Start-up Sequence” and
Section 3.7 “Fail-Safe Clock Monitor”).
The Power Control register PCON (address 8Eh) has
two Status bits to indicate what type of Reset that last
occurred.
Bit 0 is BOR (Brown-out Reset). BOR is unknown on
Power-on Reset. It must then be set by the user and
checked on subsequent Resets to see if BOR = 0,
indicating that a Brown-out has occurred. The BOR
Status bit is a “don’t care” and is not necessarily
predictable if the brown-out circuit is disabled
(BOREN<1:0> = 00 in the Configuration Word
register).
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, the time-outs will expire. Then,
bringing MCLR high will begin execution immediately
(see Figure 14-4). This is useful for testing purposes or
to synchronize more than one PIC16F685/687/689/690
device operating in parallel.
Bit 1 is POR (Power-on Reset). It is a ‘0’ on Power-on
Reset and unaffected otherwise. The user must write a
‘1’ to this bit following a Power-on Reset. On a
subsequent Reset, if POR is ‘0’, it will indicate that a
Power-on Reset has occurred (i.e., VDD may have
gone too low).
Table 14-5 shows the Reset conditions for some
special registers, while Table 14-4 shows the Reset
conditions for all the registers.
TABLE 14-1:
POWER CONTROL (PCON)
REGISTER
For more information, see Section 4.2.3 “Ultra
Low-Power
Wake-up”
and
Section 14.2.4
“Brown-Out Reset (BOR)”.
TIME-OUT IN VARIOUS SITUATIONS
Power-up
Brown-out Reset
PWRTE = 0
PWRTE = 1
PWRTE = 0
PWRTE = 1
Wake-up from
Sleep
TPWRT +
1024 • TOSC
1024 • TOSC
TPWRT +
1024 • TOSC
1024 • TOSC
1024 • TOSC
LP, T1OSCIN = 1
TPWRT
—
TPWRT
—
—
RC, EC, INTOSC
TPWRT
—
TPWRT
—
—
Oscillator Configuration
XT, HS, LP
TABLE 14-2:
STATUS/PCON BITS AND THEIR SIGNIFICANCE
POR
BOR
TO
PD
Condition
0
u
1
1
Power-on Reset
1
0
1
1
Brown-out Reset
u
u
0
u
WDT Reset
u
u
0
0
WDT Wake-up
u
u
u
u
MCLR Reset during normal operation
u
u
1
0
MCLR Reset during Sleep
Legend: u = unchanged, x = unknown
TABLE 14-3:
SUMMARY OF REGISTERS ASSOCIATED WITH BROWN-OUT
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on POR,
BOR
Value on
all other
Resets(1)
03h/83h/
103h/183h
STATUS
IRP
RP1
RPO
TO
PD
Z
DC
C
0001 1xxx
000q quuu
8Eh
PCON
—
—
ULPWUE
SBOREN
—
—
POR
BOR
--01 --qq
--0u --uu
Addr
Legend:
Note 1:
u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’, q = value depends on condition. Shaded cells are not used by BOR.
Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
DS41262A-page 178
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 14-3:
TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 1
VDD
MCLR
Internal POR
TPWRT
PWRT Time-out
TOST
OST Time-out
Internal Reset
TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 2
FIGURE 14-4:
VDD
MCLR
Internal POR
TPWRT
PWRT Time-out
TOST
OST Time-out
Internal Reset
FIGURE 14-5:
TIME-OUT SEQUENCE ON POWER-UP (MCLR WITH VDD)
VDD
MCLR
Internal POR
TPWRT
PWRT Time-out
TOST
OST Time-out
Internal Reset
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 179
PIC16F685/687/689/690
TABLE 14-4:
INITIALIZATION CONDITION FOR REGISTER
Register
Address
W
Power-on Reset
MCLR Reset
WDT Reset
Brown-out Reset(1)
Wake-up from Sleep
through Interrupt
Wake-up from Sleep
through WDT Time-out
—
xxxx xxxx
uuuu uuuu
uuuu uuuu
INDF
00h/80h/
100h/180h
xxxx xxxx
xxxx xxxx
uuuu uuuu
TMR0
01h/101h
xxxx xxxx
uuuu uuuu
uuuu uuuu
PCL
02h/82h/
102h/182h
0000 0000
0000 0000
PC + 1(3)
STATUS
03h/83h/
103h/183h
0001 1xxx
000q quuu(4)
uuuq quuu(4)
FSR
04h/84h/
104h184h
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTA
05h/105h
--xx xxxx
--00 0000
--uu uuuu
PORTB
06h/106h
xxxx ----
0000 ----
uuuu ----
PORTC
07h/107h
xxxx xxxx
0000 0000
uuuu uuuu
PCLATH
0Ah/8Ah/
10Ah/18Ah
---0 0000
---0 0000
---u uuuu
INTCON
0Bh/8Bh/
10Bh/18Bh
0000 000x
0000 000x
uuuu uuuu(2)
PIR1
0Ch
-000 0000
-000 0000
-uuu uuuu(2)
PIR2
0Dh
0000 ----
0000 ----
uuuu ----(2)
TMR1L
0Eh
xxxx xxxx
uuuu uuuu
uuuu uuuu
TMR1H
0Fh
xxxx xxxx
uuuu uuuu
uuuu uuuu
T1CON
10h
0000 0000
uuuu uuuu
uuuu uuuu
TMR2
11h
0000 0000
0000 0000
uuuu uuuu
T2CON
12h
-000 0000
-000 0000
-uuu uuuu
SSPBUF
13h
xxxx xxxx
xxxx xxxx
uuuu uuuu
SSPCON
14h
0000 0000
0000 0000
uuuu uuuu
CCPR1L
15h
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCPR1H
16h
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCP1CON
17h
0000 0000
0000 0000
uuuu uuuu
RCSTA
18h
0000 000x
0000 000x
uuuu uuuu
TXREG
19h
0000 0000
0000 0000
uuuu uuuu
RCREG
1Ah
0000 0000
0000 0000
uuuu uuuu
PWM1CON
1Ch
0000 0000
0000 0000
uuuu uuuu
ECCPAS
1Dh
0000 0000
0000 0000
uuuu uuuu
ADRESH
1Eh
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADCON0
1Fh
0000 0000
0000 0000
uuuu uuuu
OPTION_REG
81h/181h
1111 1111
1111 1111
uuuu uuuu
TRISA
85h/185h
--11 1111
--11 1111
--uu uuuu
Legend:
Note 1:
2:
3:
4:
5:
6:
u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’, q = value depends on condition.
If VDD goes too low, Power-on Reset will be activated and registers will be affected differently.
One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up).
When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).
See Table 14-5 for Reset value for specific condition.
If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u.
Accessible only when SSPM<3:0> = 1001.
DS41262A-page 180
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 14-4:
INITIALIZATION CONDITION FOR REGISTER (CONTINUED)
Wake-up from Sleep
through Interrupt
Wake-up from Sleep
through WDT Time-out
Address
Power-on Reset
MCLR Reset
WDT Reset (Continued)
Brown-out Reset(1)
TRISB
86h/186h
1111 ----
1111 ----
uuuu ----
TRISC
Register
87h/187h
1111 1111
1111 1111
uuuu uuuu
PIE1
8Ch
-000 0000
-000 0000
-uuu uuuu
PIE2
8Dh
0000 ----
0000 ----
uuuu uuuu
(1, 5)
PCON
8Eh
--01 --qq
OSCCON
8Fh
-110 q000
-110 x000
-uuu uuuu
OSCTUNE
90h
---0 0000
---u uuuu
---u uuuu
PR2
92h
1111 1111
1111 1111
1111 1111
SSPADD
93h
0000 0000
1111 1111
uuuu uuuu
(6)
--0u --uu
--uu --uu
93h
---- ----
1111 1111
uuuu uuuu
SSPSTAT
94h
0000 0000
1111 1111
uuuu uuuu
WPUA
95h
--11 -111
--11 -111
uuuu uuuu
IOCA
96h
--00 0000
--00 0000
--uu uuuu
WDTCON
97h
---0 1000
---0 1000
---u uuuu
TXSTA
98h
0000 0010
0000 0010
uuuu uuuu
SPBRG
99h
0000 0000
0000 0000
uuuu uuuu
SPBRGH
9Ah
0000 0000
0000 0000
uuuu uuuu
BAUDCTL
9Bh
01-0 0-00
01-0 0-00
uu-u u-uu
ADRESL
9Eh
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADCON1
9Fh
-000 ----
-000 ----
-uuu ----
EEDAT
10Ch
0000 0000
0000 0000
uuuu uuuu
EEADR
10Dh
0000 0000
0000 0000
uuuu uuuu
EEDATH
10Eh
--00 0000
--00 0000
--uu uuuu
EEADRH
10Fh
---- 0000
---- 0000
---- uuuu
WPUB
115h
1111 ----
1111 ----
uuuu ----
IOCB
116h
0000 ----
0000 ----
uuuu ----
VRCON
118h
0000 0000
0000 0000
uuuu uuuu
CM1CON0
119h
0000 -000
0000 -000
uuuu -uuu
CM2CON0
11Ah
0000 -000
0000 -000
uuuu -uuu
CM2CON1
11Bh
00-- --00
00-- --10
uu-- --uu
ANSEL
11Eh
1111 1111
1111 1111
uuuu uuuu
ANSELH
11Fh
---- 1111
---- 1111
---- uuuu
EECON1
18Ch
x--- x000
u--- q000
---- uuuu
EECON2
18Dh
---- ----
---- ----
---- ----
PSTRCON
19Dh
---0 0001
---0 0001
---u uuuu
SRCON
19EH
0000 00--
0000 00--
uuuu uu--
SSPMSK
Legend:
Note 1:
2:
3:
4:
5:
6:
u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’, q = value depends on condition.
If VDD goes too low, Power-on Reset will be activated and registers will be affected differently.
One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up).
When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).
See Table 14-5 for Reset value for specific condition.
If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u.
Accessible only when SSPM<3:0> = 1001.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 181
PIC16F685/687/689/690
TABLE 14-5:
INITIALIZATION CONDITION FOR SPECIAL REGISTERS
Program
Counter
Status
Register
PCON
Register
Power-on Reset
000h
0001 1xxx
--01 --0x
MCLR Reset during normal operation
000h
000u uuuu
--0u --uu
MCLR Reset during Sleep
000h
0001 0uuu
--0u --uu
000h
0000 uuuu
--0u --uu
PC + 1
uuu0 0uuu
--uu --uu
Condition
WDT Reset
WDT Wake-up
Brown-out Reset
Interrupt Wake-up from Sleep
000h
0001 1uuu
--01 --10
PC + 1(1)
uuu1 0uuu
--uu --uu
Legend: u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’.
Note 1: When the wake-up is due to an interrupt and Global Interrupt Enable bit, GIE, is set, the PC is loaded with
the interrupt vector (0004h) after execution of PC + 1.
DS41262A-page 182
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
14.3
Interrupts
When an interrupt is serviced:
The PIC16F685/687/689/690 have multiple sources of
interrupt:
•
•
•
•
•
•
•
•
•
•
•
External Interrupt RA2/INT
TMR0 Overflow Interrupt
PORTA/PORTB Change Interrupts
2 Comparator Interrupts
A/D Interrupt
Timer1 Overflow Interrupt
Timer2 Match Interrupt
EEPROM Data Write Interrupt
Fail-Safe Clock Monitor Interrupt
Enhanced CCP Interrupt
EUSART Receive and Transmit interrupts
For external interrupt events, such as the INT pin,
PORTA/PORTB change interrupts, the interrupt
latency will be three or four instruction cycles. The
exact latency depends upon when the interrupt event
occurs (see Figure 14-7). The latency is the same for
one or two-cycle instructions. Once in the Interrupt
Service Routine, the source(s) of the interrupt can be
determined by polling the interrupt flag bits. The
interrupt flag bit(s) must be cleared in software before
re-enabling interrupts to avoid multiple interrupt
requests.
The Interrupt Control register (INTCON) and Peripheral
Interrupt Request Register 1 (PIR1) record individual
interrupt requests in flag bits. The INTCON register
also has individual and global interrupt enable bits.
A Global Interrupt Enable bit, GIE (INTCON<7>),
enables (if set) all unmasked interrupts, or disables (if
cleared) all interrupts. Individual interrupts can be
disabled through their corresponding enable bits in the
INTCON, PIE1 and PIE2 registers, respectively. GIE is
cleared on Reset.
The Return from Interrupt instruction, RETFIE, exits
the interrupt routine, as well as sets the GIE bit, which
re-enables unmasked interrupts.
The following interrupt flags are contained in the
INTCON register:
• INT Pin Interrupt
• PORTA/PORTB Change Interrupts
• TMR0 Overflow Interrupt
The peripheral interrupt flags are contained in the
special registers, PIR1 and PIR2. The corresponding
interrupt enable bits are contained in special registers,
PIE1 and PIE2.
The following interrupt flags are contained in the PIR1
register:
•
•
•
•
•
•
•
• The GIE is cleared to disable any further interrupt.
• The return address is pushed onto the stack.
• The PC is loaded with 0004h.
A/D Interrupt
EUSART Receive and Transmit Interrupts
Timer1 Overflow Interrupt
Synchronous Serial Port (SSP) Interrupt
Enhanced CCP1 Interrupt
Timer1 Overflow Interrupt
Timer2 Match Interrupt
Note 1: Individual interrupt flag bits are set,
regardless of the status of their
corresponding mask bit or the GIE bit.
2: When an instruction that clears the GIE
bit is executed, any interrupts that were
pending for execution in the next cycle
are ignored. The interrupts, which were
ignored, are still pending to be serviced
when the GIE bit is set again.
For additional information on Timer1, Timer2,
comparators, A/D, data EEPROM, EUSART, SSP or
Enhanced CCP modules, refer to the respective
peripheral section.
14.3.1
RA2/INT INTERRUPT
External interrupt on RA2/INT pin is edge-triggered;
either rising if the INTEDG bit (OPTION_REG<6>) is
set, or falling, if the INTEDG bit is clear. When a valid
edge appears on the RA2/INT pin, the INTF bit
(INTCON<1>) is set. This interrupt can be disabled by
clearing the INTE control bit (INTCON<4>). The INTF
bit must be cleared in software in the Interrupt Service
Routine before re-enabling this interrupt. The RA2/INT
interrupt can wake-up the processor from Sleep, if the
INTE bit was set prior to going into Sleep. The status of
the GIE bit decides whether or not the processor
branches to the interrupt vector following wake-up
(0004h). See Section 14.6 “Power-Down Mode
(Sleep)” for details on Sleep and Figure 14-9 for timing
of wake-up from Sleep through RA2/INT interrupt.
Note:
The ANSEL (11Eh) and CM2CON0 (11Ah)
registers must be initialized to configure
an analog channel as a digital input. Pins
configured as analog inputs will read ‘0’.
The following interrupt flags are contained in the PIR2
register:
14.3.2
• Fail-Safe Clock Monitor Interrupt
• 2 Comparator Interrupts
• EEPROM Data Write Interrupt
An overflow (FFh → 00h) in the TMR0 register will set
the T0IF (INTCON<2>) bit. The interrupt can be
enabled/disabled by setting/clearing T0IE (INTCON<5>)
bit. See Section 5.0 “Timer0 Module” for operation of
the Timer0 module.
© 2005 Microchip Technology Inc.
Preliminary
TMR0 INTERRUPT
DS41262A-page 183
PIC16F685/687/689/690
14.3.3
PORTA/PORTB INTERRUPT
An input change on PORTA or PORTB change sets the
RABIF (INTCON<0>) bit. The interrupt can be
enabled/disabled by setting/clearing the RABIE
(INTCON<3>) bit. Plus, individual pins can be
configured through the IOCA or IOCB registers.
Note:
If a change on the I/O pin should occur
when the read operation is being executed
(start of the Q2 cycle), then the RABIF
interrupt flag may not get set. See
Section 4.2.2 “Interrupt-on-change” for
more information.
FIGURE 14-6:
INTERRUPT LOGIC
IOC-RA0
IOCA0
IOC-RA1
IOCA1
IOC-RA2
IOCA2
IOC-RA3
IOCA3
IOC-RA4
IOCA4
IOC-RA5
IOCA5
IOC-RB4
IOCB4
IOC-RB5
IOCB5
IOC-RB6
IOCB6
IOC-RB7
IOCB7
SSPIF
SSPIE
TXIF
TXIE
RCIF
RCIE
Wake-up (If in Sleep mode)(1)
T0IF
T0IE
TMR2IF
TMR2IE
Interrupt to CPU
INTF
INTE
RABIF
RABIE
TMR1IF
TMR1IE
C1IF
C1IE
PEIE
C2IF
C2IE
GIE
ADIF
ADIE
EEIF
EEIE
Note 1:
OSFIF
OSFIE
CCP1IF
CCP1IE
DS41262A-page 184
Preliminary
Some peripherals depend upon the system
clock for operation. Since the system clock is
suspended during Sleep, these peripherals
will not wake the part from Sleep. See
Section 14.6.1 “Wake-up from Sleep”.
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 14-7:
INT PIN INTERRUPT TIMING
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
OSC1
CLKOUT (3)
(4)
INT pin
(1)
(1)
INTF flag
(INTCON<1>)
Interrupt Latency (2)
(5)
GIE bit
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
Note 1:
Inst (PC + 1)
Inst (PC)
0005h
Inst (0004h)
Inst (0005h)
Dummy Cycle
Inst (0004h)
—
Dummy Cycle
Inst (PC)
0004h
PC + 1
PC + 1
Inst (PC – 1)
INTF flag is sampled here (every Q1).
2:
Asynchronous interrupt latency = 3-4 TCY. Synchronous latency = 3 TCY, where TCY = instruction cycle time. Latency
is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.
3:
CLKOUT is available only in INTOSC and RC Oscillator modes.
4:
For minimum width of INT pulse, refer to AC specifications in Section 17.0 “Electrical Specifications”.
5:
INTF is enabled to be set any time during the Q4-Q1 cycles.
TABLE 14-6:
Address
PC
Name
0Bh/8Bh/
INTCON
10Bh/18Bh
SUMMARY OF INTERRUPT REGISTERS
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
GIE
PEIE
T0IE
INTE
RABIE
T0IF
INTF
RABIF
0000 000x
0000 000x
-000 0000
0Ch
PIR1
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
-000 0000
0Dh
PIR2
OSFIF
C2IF
C1IF
EEIF
—
—
—
—
0000 ----
0000 ----
8Ch
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
-000 0000
-000 0000
8Dh
PIE2
OSFIE
C2IE
C1IE
EEIE
—
—
—
—
0000 ----
0000 ----
Legend:
x = unknown, u = unchanged, — = unimplemented read as ‘0’, q = value depends upon condition.
Shaded cells are not used by the interrupt module.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 185
PIC16F685/687/689/690
14.4
Context Saving During Interrupts
During an interrupt, only the return PC value is saved
on the stack. Typically, users may wish to save key
registers during an interrupt (e.g., W and Status
registers). This must be implemented in software.
Since the upper 16 bytes of all GPR banks are common
in the PIC16F685/687/689/690 (see Figures 2-1
and 2-2), temporary holding registers, W_TEMP and
STATUS_TEMP, should be placed in here. These 16
locations do not require banking and therefore, make it
easier to context save and restore. The same code
shown in Example 14-1 can be used to:
•
•
•
•
•
Store the W register
Store the Status register
Execute the ISR code
Restore the Status (and Bank Select Bit register)
Restore the W register
Note:
The PIC16F685/687/689/690 normally
does not require saving the PCLATH.
However, if computed GOTO’s are used in
the ISR and the main code, the PCLATH
must be saved and restored in the ISR.
EXAMPLE 14-1:
MOVWF
SWAPF
CLRF
MOVWF
SAVING STATUS AND W REGISTERS IN RAM
W_TEMP
STATUS,W
STATUS
STATUS_TEMP
;Copy
;Swap
;bank
;Save
W to TEMP register
status to be saved into W
0, regardless of current bank, Clears IRP,RP1,RP0
status to bank zero STATUS_TEMP register
:
:(ISR)
:
SWAPF STATUS_TEMP,W
;Insert user code here
;Swap STATUS_TEMP register into W
MOVWF
SWAPF
SWAPF
;Move W into Status register
;Swap W_TEMP
;Swap W_TEMP into W
;(sets bank to original state)
STATUS
W_TEMP,F
W_TEMP,W
DS41262A-page 186
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
14.5
14.5.2
Watchdog Timer (WDT)
The new WDT is functionally compatible with
previously designed WDT modules from other
PICmicro® microcontrollers. Besides being backwards
compatible, the WDT module has added capabilities to
control a 16-bit prescaler through software. This allows
the user to modify the prescale value for the WDT and
TMR0 independently. Additionally, the WDT time-out
value can be extended to 268 seconds because of the
16-bit prescaler. The WDT is cleared under certain
conditions, which are described in Table 14-7.
14.5.1
WDT OSCILLATOR
The WDT derives its time base from the 31 kHz
LFINTOSC oscillator, and on any Reset, the value of
WDTCON is ‘---0 1000’. The resultant Reset value
for WDTCON yields a nominal time base of 16 ms for
the WDT. The new prescaler, that was added to the
path between the LFINTOSC oscillator and the
multiplexers, is used to divide the LFINTOSC oscillator
by values between 32 and 65536. As a result of the
combination of prescalers, a nominal range of 1 ms to
268s time out period for the WDT can be achieved.
Figure 14-8 shows a block diagram of the WDT
circuitry and where the new prescaler was designed
into the circuit.
FIGURE 14-8:
WDT CONTROL
When the WDTE bit (CONFIG<3>) is set, it enables the
WDT and will continuously run. When the bit is clear,
the WDT is disabled, but can be controlled through
software in program memory and then SWDTEN bit
(WDTCON<0>) has no effect. If WDTE is clear, the
SWDTEN bit can be used to enable and disable the
WDT through software in program memory.
The PSA<3> and PS<2:0> bits in the OPTION register
(Register 2-2) have the same function as the WDT
modules
previously
designed
for
PICmicro
microcontrollers. See Section 5.0 “Timer0 Module”
for more information about the OPTION register.
Note:
When the Oscillator Start-up Timer (OST)
is invoked, the WDT is held in Reset,
because the WDT Ripple Counter is used
by the OST to perform the oscillator delay
count. When the OST count has expired,
the WDT will begin counting (if enabled).
WATCHDOG TIMER BLOCK DIAGRAM
From TMR0 Clock Source
0
Prescaler(1)
16-bit WDT Prescaler
1
8
PSA
31 kHz
LFINTOSC Clock
PS<2:0>
WDTPS<3:0>
To TMR0
0
1
PSA
WDTE from the Configuration Word Register
SWDTEN from WDTCON
WDT Time-out
Note
1:
TABLE 14-7:
This is the shared Timer0/WDT prescaler. See Section 5.4 “Prescaler” for more information.
WDT STATUS
Conditions
WDT
WDTE = 0
Cleared
CLRWDT Command
Oscillator Fail Detected
Exit Sleep + System Clock = T1OSC, EXTRC, INTOSC, EXTCLK
Exit Sleep + System Clock = XT, HS, LP
© 2005 Microchip Technology Inc.
Cleared until the end of OST
Preliminary
DS41262A-page 187
PIC16F685/687/689/690
REGISTER 14-2:
WDTCON – WATCHDOG TIMER CONTROL REGISTER (ADDRESS: 97h)
U-0
U-0
U-0
R/W-0
R/W-1
R/W-0
—
—
—
WDTPS3
WDTPS2
WDTPS1
R/W-0
R/W-0
WDTPS0 SWDTEN(1)
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-1
WDTPS<3:0>: Watchdog Timer Period Select bits
Bit Value = Prescale Rate
0000 = 1:32
0001 = 1:64
0010 = 1:128
0011 = 1:256
0100 = 1:512 (Reset value)
0101 = 1:1024
0110 = 1:2048
0111 = 1:4096
1000 = 1:8192
1001 = 1:16384
1010 = 1:32768
1011 = 1:65536
1100 = reserved
1101 = reserved
1110 = reserved
1111 = reserved
bit 0
SWDTEN: Software Enable or Disable the Watchdog Timer(1)
1 = WDT is turned on
0 = WDT is turned off (Reset value)
Note 1: If WDTE configuration bit = 1, then WDT is always enabled, irrespective of this
control bit. If WDTE configuration bit = 0, then it is possible to turn WDT on/off with
this control bit.
Legend:
TABLE 14-8:
Address
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
SUMMARY OF WATCHDOG TIMER REGISTERS
Name
97h
WDTCON
81h/181h
OPTION_REG
2007h
(1)
Legend:
Note 1:
x = Bit is unknown
CONFIG
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
—
—
—
WDTPS3
WDTPS2
WSTPS1
WDTPS0
SWDTEN
RABPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
CPD
CP
MCLRE
PWRTE
WDTE
FOSC2
FOSC1
FOSC0
Shaded cells are not used by the Watchdog Timer.
See Register 14-1 for operation of all Configuration Word register bits.
DS41262A-page 188
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
14.6
Power-Down Mode (Sleep)
The Power-down mode is entered by executing a
SLEEP instruction.
If the Watchdog Timer is enabled:
•
•
•
•
•
WDT will be cleared but keeps running.
PD bit in the Status register is cleared.
TO bit is set.
Oscillator driver is turned off.
I/O ports maintain the status they had before
SLEEP was executed (driving high, low or
high-impedance).
For lowest current consumption in this mode, all I/O pins
should be either at VDD or VSS, with no external circuitry
drawing current from the I/O pin and the comparators
and CVREF should be disabled. I/O pins that are
high-impedance inputs should be pulled high or low
externally to avoid switching currents caused by floating
inputs. The T0CKI input should also be at VDD or VSS for
lowest current consumption. The contribution from
on-chip pull-ups on PORTA should be considered.
The MCLR pin must be at a logic high level.
Note:
14.6.1
It should be noted that a Reset generated
by a WDT time-out does not drive MCLR
pin low.
WAKE-UP FROM SLEEP
The device can wake-up from Sleep through one of the
following events:
1.
2.
3.
External Reset input on MCLR pin.
Watchdog Timer wake-up (if WDT was enabled).
Interrupt from RA2/INT pin, PORTA change or a
peripheral interrupt.
The first event will cause a device Reset. The two latter
events are considered a continuation of program
execution. The TO and PD bits in the Status register
can be used to determine the cause of device Reset.
The PD bit, which is set on power-up, is cleared when
Sleep is invoked. TO bit is cleared if WDT wake-up
occurred.
The following peripheral interrupts can wake the device
from Sleep:
1.
2.
3.
4.
5.
6.
7.
8.
9.
TMR1 interrupt. Timer1 must be operating as an
asynchronous counter.
ECCP Capture mode interrupt.
Special event trigger (Timer1 in Asynchronous
mode using an external clock).
A/D conversion (when A/D clock source is RC).
EEPROM write operation completion.
Comparator output changes state.
Interrupt-on-change.
External Interrupt from INT pin.
EUSART Break detect, I2C slave.
© 2005 Microchip Technology Inc.
Other peripherals cannot generate interrupts since
during Sleep, no on-chip clocks are present.
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up is
regardless of the state of the GIE bit. If the GIE bit is
clear (disabled), the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
set (enabled), the device executes the instruction after
the SLEEP instruction, then branches to the interrupt
address (0004h). In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOP after the SLEEP instruction.
Note:
If the global interrupts are disabled (GIE is
cleared), but any interrupt source has both
its interrupt enable bit and the corresponding
interrupt flag bits set, the device will
immediately wake-up from Sleep. The
SLEEP instruction is completely executed.
The WDT is cleared when the device wakes up from
Sleep, regardless of the source of wake-up.
14.6.2
WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
SLEEP instruction, the SLEEP instruction will
complete as a NOP. Therefore, the WDT and WDT
prescaler and postscaler (if enabled) will not be
cleared, the TO bit will not be set and the PD bit
will not be cleared.
• If the interrupt occurs during or after the
execution of a SLEEP instruction, the device will
immediately wake-up from Sleep. The SLEEP
instruction will be completely executed before the
wake-up. Therefore, the WDT and WDT prescaler
and postscaler (if enabled) will be cleared, the TO
bit will be set and the PD bit will be cleared.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT instruction
should be executed before a SLEEP instruction.
Preliminary
DS41262A-page 189
PIC16F685/687/689/690
FIGURE 14-9:
WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
TOST(2)
CLKOUT(4)
INT pin
INTF flag
(INTCON<1>)
Interrupt Latency (3)
GIE bit
(INTCON<7>)
Processor in
Sleep
Instruction Flow
PC
Instruction
Fetched
Instruction
Executed
Note
14.7
PC
Inst(PC) = Sleep
Inst(PC – 1)
PC + 1
PC + 2
Inst(PC + 1)
Inst(PC + 2)
Sleep
Inst(PC + 1)
14.8
Dummy Cycle
0004h
0005h
Inst(0004h)
Inst(0005h)
Dummy Cycle
Inst(0004h)
XT, HS or LP Oscillator mode assumed.
2:
TOST = 1024 TOSC (drawing not to scale). This delay does not apply to EC and RC Oscillator modes.
3:
GIE = 1 assumed. In this case after wake-up, the processor jumps to 0004h. If GIE = 0, execution will continue in-line.
4:
CLKOUT is not available in XT, HS, LP or EC Oscillator modes, but shown here for timing reference.
Code Protection
The entire data EEPROM and Flash
program memory will be erased when the
code protection is switched from on to off.
See the “PIC12F6XX/16F6XX Memory
Programming Specification” (DS41204)
for more information.
ID Locations
Four memory locations (2000h-2003h) are designated
as ID locations where the user can store checksum or
other code identification numbers. These locations are
not accessible during normal execution but are
readable and writable during Program/Verify mode.
Only the Least Significant 7 bits of the ID locations are
used.
14.9
PC + 2
1:
If the code protection bit(s) have not been
programmed, the on-chip program memory can be
read out using ICSP™ for verification purposes.
Note:
PC + 2
In-Circuit Serial Programming
The PIC16F685/687/689/690 microcontrollers can be
serially programmed while in the end application circuit.
This is simply done with two lines for clock and data
and three other lines for:
This allows customers to manufacture boards with
unprogrammed devices and then program the microcontroller just before shipping the product. This also
allows the most recent firmware or a custom firmware
to be programmed.
The device is placed into a Program/Verify mode by
holding the RA0/AN0/C1IN+/ICSPDAT/ULPWU and
RA1/AN1/C12IN-/VREF/ICSPCLK pins low, while raising the MCLR (VPP) pin from VIL to VIHH. See the
“PIC12F6XX/16F6XX Memory Programming Specification” (DS41204) for more information. RA0 becomes
the programming data and RA1 becomes the
programming clock. Both RA0 and RA1 are Schmitt
Trigger inputs in this mode.
After Reset, to place the device into Program/Verify
mode, the Program Counter (PC) is at location 00h. A
6-bit command is then supplied to the device.
Depending on the command, 14 bits of program data
are then supplied to or from the device, depending on
whether the command was a load or a read. For
complete details of serial programming, please refer to
the “PIC12F6XX/16F6XX Memory Programming
Specification” (DS41204).
A typical In-Circuit Serial Programming connection is
shown in Figure 14-10.
• power
• ground
• programming voltage
DS41262A-page 190
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 14-10:
TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
To Normal
Connections
External
Connector
Signals
PIC16F685/
687/689/690
*
+5V
VDD
0V
VSS
VPP
RA3/MCLR/VPP
CLK
RA1
Data I/O
RA0
*
*
*
To Normal
Connections
*
Isolation devices (as required)
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 191
PIC16F685/687/689/690
NOTES:
DS41262A-page 192
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
15.0
INSTRUCTION SET SUMMARY
The PIC16F685/687/689/690 instruction set is highly
orthogonal and is comprised of three basic categories:
• Byte-oriented operations
• Bit-oriented operations
• Literal and control operations
For example, a CLRF PORTA instruction will read
PORTA, clear all the data bits, then write the result back
to PORTA. This example would have the unintended
result of clearing the condition that set the RABIF flag.
TABLE 15-1:
Each PIC16 instruction is a 14-bit word divided into an
opcode, which specifies the instruction type and one or
more operands, which further specify the operation of
the instruction. The formats for each of the categories
is presented in Figure 15-1, while the various opcode
fields are summarized in Table 15-1.
Field
Table 15-2 lists the instructions recognized by the
MPASMTM assembler.
For byte-oriented instructions, ‘f’ represents a file
register designator and ‘d’ represents a destination
designator. The file register designator specifies which
file register is to be used by the instruction.
The destination designator specifies where the result of
the operation is to be placed. If ‘d’ is zero, the result is
placed in the W register. If ‘d’ is one, the result is placed
in the file register specified in the instruction.
For bit-oriented instructions, ‘b’ represents a bit field
designator, which selects the bit affected by the
operation, while ‘f’ represents the address of the file in
which the bit is located.
Description
f
Register file address (0x00 to 0x7F)
W
Working register (accumulator)
b
Bit address within an 8-bit file register
k
Literal field, constant data or label
x
Don’t care location (= 0 or 1).
The assembler will generate code with x = 0.
It is the recommended form of use for
compatibility with all Microchip software tools.
d
Destination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1.
PC
Program Counter
TO
Time-out bit
PD
Power-down bit
FIGURE 15-1:
For literal and control operations, ‘k’ represents an
8-bit or 11-bit constant, or literal value.
One instruction cycle consists of four oscillator periods;
for an oscillator frequency of 4 MHz, this gives a normal
instruction execution time of 1 μs. All instructions are
executed within a single instruction cycle, unless a
conditional test is true, or the program counter is
changed as a result of an instruction. When this occurs,
the execution takes two instruction cycles, with the
second cycle executed as a NOP.
Note:
OPCODE FIELD
DESCRIPTIONS
To maintain upward compatibility with
future products, do not use the OPTION
and TRIS instructions.
All instruction examples use the format ‘0xhh’ to
represent a hexadecimal number, where ‘h’ signifies a
hexadecimal digit.
GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
13
8 7 6
OPCODE
d
f (FILE #)
d = 0 for destination W
d = 1 for destination f
f = 7-bit file register address
Bit-oriented file register operations
13
10 9
7 6
OPCODE
b (BIT #)
Literal and control operations
General
13
Read-Modify-Write Operations
8
7
0
k (literal)
k = 8-bit immediate value
Any instruction that specifies a file register as part of
the instruction performs a Read-Modify-Write (RMW)
operation. The register is read, the data is modified,
and the result is stored according to either the instruction, or the destination designator ‘d’. A read operation
is performed on a register even if the instruction writes
to that register.
© 2005 Microchip Technology Inc.
0
f (FILE #)
b = 3-bit bit address
f = 7-bit file register address
OPCODE
15.1
0
Preliminary
CALL and GOTO instructions only
13
11
OPCODE
10
0
k (literal)
k = 11-bit immediate value
DS41262A-page 193
PIC16F685/687/689/690
TABLE 15-2:
PIC16F685/687/689/690 INSTRUCTION SET
Mnemonic,
Operands
14-Bit Opcode
Description
Cycles
MSb
LSb
Status
Affected
Notes
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF
ANDWF
CLRF
CLRW
COMF
DECF
DECFSZ
INCF
INCFSZ
IORWF
MOVF
MOVWF
NOP
RLF
RRF
SUBWF
SWAPF
XORWF
f, d
f, d
f
–
f, d
f, d
f, d
f, d
f, d
f, d
f, d
f
–
f, d
f, d
f, d
f, d
f, d
Add W and f
AND W with f
Clear f
Clear W
Complement f
Decrement f
Decrement f, Skip if 0
Increment f
Increment f, Skip if 0
Inclusive OR W with f
Move f
Move W to f
No Operation
Rotate Left f through Carry
Rotate Right f through Carry
Subtract W from f
Swap nibbles in f
Exclusive OR W with f
BCF
BSF
BTFSC
BTFSS
f, b
f, b
f, b
f, b
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
1
1
1
1
1
1
1(2)
1
1(2)
1
1
1
1
1
1
1
1
1
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
dfff
dfff
lfff
0xxx
dfff
dfff
dfff
dfff
dfff
dfff
dfff
lfff
0xx0
dfff
dfff
dfff
dfff
dfff
ffff
ffff
ffff
xxxx
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
0000
ffff
ffff
ffff
ffff
ffff
00bb
01bb
10bb
11bb
bfff
bfff
bfff
bfff
ffff
ffff
ffff
ffff
111x
1001
0kkk
0000
1kkk
1000
00xx
0000
01xx
0000
0000
110x
1010
kkkk
kkkk
kkkk
0110
kkkk
kkkk
kkkk
0000
kkkk
0000
0110
kkkk
kkkk
kkkk
kkkk
kkkk
0100
kkkk
kkkk
kkkk
1001
kkkk
1000
0011
kkkk
kkkk
0111
0101
0001
0001
1001
0011
1011
1010
1111
0100
1000
0000
0000
1101
1100
0010
1110
0110
C, DC, Z
Z
Z
Z
Z
Z
Z
Z
Z
C
C
C, DC, Z
Z
1, 2
1, 2
2
1, 2
1, 2
1, 2, 3
1, 2
1, 2, 3
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2
BIT-ORIENTED FILE REGISTER OPERATIONS
1
1
1 (2)
1 (2)
01
01
01
01
1, 2
1, 2
3
3
LITERAL AND CONTROL OPERATIONS
ADDLW
ANDLW
CALL
CLRWDT
GOTO
IORLW
MOVLW
RETFIE
RETLW
RETURN
SLEEP
SUBLW
XORLW
Note 1:
2:
3:
k
k
k
–
k
k
k
–
k
–
–
k
k
Add literal and W
AND literal with W
Call Subroutine
Clear Watchdog Timer
Go to address
Inclusive OR literal with W
Move literal to W
Return from interrupt
Return with literal in W
Return from Subroutine
Go into Standby mode
Subtract W from literal
Exclusive OR literal with W
1
1
2
1
2
1
1
2
2
2
1
1
1
11
11
10
00
10
11
11
00
11
00
00
11
11
C, DC, Z
Z
TO, PD
Z
TO, PD
C, DC, Z
Z
When an I/O register is modified as a function of itself (e.g., MOVF PORTA, 1), the value used will be that value present
on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is driven low by an external
device, the data will be written back with a ‘0’.
If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared if
assigned to the Timer0 module.
If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second
cycle is executed as a NOP.
DS41262A-page 194
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
15.2
Instruction Descriptions
ADDLW
Add literal and W
Syntax:
[ label ] ADDLW
Operands:
0 ≤ k ≤ 255
Operation:
(W) + k → (W)
Status Affected:
C, DC, Z
Description:
The contents of the W register
are added to the eight-bit literal ‘k’
and the result is placed in the
W register.
k
BCF
Bit Clear f
Syntax:
[ label ] BCF
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
0 → (f<b>)
Status Affected:
None
Description:
Bit ‘b’ in register ‘f’ is cleared.
BSF
Bit Set f
Syntax:
[ label ] BSF
f,b
ADDWF
Add W and f
Syntax:
[ label ] ADDWF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
(W) + (f) → (destination)
Operation:
1 → (f<b>)
Status Affected:
C, DC, Z
Status Affected:
None
Description:
Add the contents of the W register
with register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W register. If
‘d’ is ‘1’, the result is stored back
in register ‘f’.
Description:
Bit ‘b’ in register ‘f’ is set.
ANDLW
AND literal with W
BTFSC
Bit Test f, Skip if Clear
Syntax:
[ label ] ANDLW
Syntax:
[ label ] BTFSC f,b
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
(W) .AND. (k) → (W)
0 ≤ f ≤ 127
0≤b≤7
Status Affected:
Z
Operation:
skip if (f<b>) = 0
Description:
The contents of W register are
AND’ed with the eight-bit literal
‘k’. The result is placed in the W
register.
Status Affected:
None
Description:
If bit ‘b’ in register ‘f’ is ‘1’, the next
instruction is executed.
If bit ‘b’ in register ‘f’ is ‘0’, the next
instruction is discarded, and a NOP
is executed instead, making this a
two-cycle instruction.
ANDWF
f,d
k
AND W with f
Syntax:
[ label ] ANDWF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) .AND. (f) → (destination)
f,d
Status Affected:
Z
Description:
AND the W register with register
‘f’. If ‘d’ is ‘0’, the result is stored in
the W register. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
© 2005 Microchip Technology Inc.
f,b
Preliminary
DS41262A-page 195
PIC16F685/687/689/690
BTFSS
Bit Test f, Skip if Set
CLRWDT
Clear Watchdog Timer
Syntax:
[ label ] BTFSS f,b
Syntax:
[ label ] CLRWDT
Operands:
0 ≤ f ≤ 127
0≤b<7
Operands:
None
Operation:
00h → WDT
0 → WDT prescaler,
1 → TO
1 → PD
Status Affected:
TO, PD
Description:
CLRWDT instruction resets the
Watchdog Timer. It also resets the
prescaler of the WDT.
Status bits TO and PD are set.
Operation:
skip if (f<b>) = 1
Status Affected:
None
Description:
If bit ‘b’ in register ‘f’ is ‘0’, the next
instruction is executed.
If bit ‘b’ is ‘1’, then the next
instruction is discarded and a NOP
is executed instead, making this a
two-cycle instruction.
CALL
Call Subroutine
COMF
Complement f
Syntax:
[ label ] CALL k
Syntax:
[ label ] COMF
Operands:
0 ≤ k ≤ 2047
Operands:
Operation:
(PC)+ 1→ TOS,
k → PC<10:0>,
(PCLATH<4:3>) → PC<12:11>
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) → (destination)
Status Affected:
Z
Description:
The contents of register ‘f’ are
complemented. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’,
the result is stored back in
register ‘f’.
DECF
Decrement f
Syntax:
[ label ] DECF f,d
f,d
Status Affected:
None
Description:
Call Subroutine. First, return
address (PC + 1) is pushed onto
the stack. The eleven-bit
immediate address is loaded into
PC bits <10:0>. The upper bits of
the PC are loaded from PCLATH.
CALL is a two-cycle instruction.
CLRF
Clear f
Syntax:
[ label ] CLRF
Operands:
0 ≤ f ≤ 127
Operands:
Operation:
00h → (f)
1→Z
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) - 1 → (destination)
Status Affected:
Z
Status Affected:
Z
Description:
The contents of register ‘f’ are
cleared and the Z bit is set.
Description:
Decrement register ‘f’. If ‘d’ is ‘0’,
the result is stored in the W
register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
CLRW
Clear W
Syntax:
[ label ] CLRW
f
Operands:
None
Operation:
00h → (W)
1→Z
Status Affected:
Z
Description:
W register is cleared. Zero bit (Z)
is set.
DS41262A-page 196
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
DECFSZ
Decrement f, Skip if 0
INCFSZ
Increment f, Skip if 0
Syntax:
[ label ] DECFSZ f,d
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) - 1 → (destination);
skip if result = 0
Operation:
(f) + 1 → (destination),
skip if result = 0
Status Affected:
None
Status Affected:
None
Description:
The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result
is placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
If the result is ‘1’, the next
instruction is executed. If the
result is ‘0’, then a NOP is
executed instead, making it a
two-cycle instruction.
Description:
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result
is placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
If the result is ‘1’, the next
instruction is executed. If the
result is ‘0’, a NOP is executed
instead, making it a two-cycle
instruction.
GOTO
Unconditional Branch
IORLW
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 2047
Operands:
0 ≤ k ≤ 255
Operation:
k → PC<10:0>
PCLATH<4:3> → PC<12:11>
Operation:
(W) .OR. k → (W)
Status Affected:
Z
Status Affected:
None
Description:
Description:
GOTO is an unconditional branch.
The eleven-bit immediate value is
loaded into PC bits <10:0>. The
upper bits of PC are loaded from
PCLATH<4:3>. GOTO is a
two-cycle instruction.
The contents of the W register are
OR’ed with the eight-bit literal ‘k’.
The result is placed in the
W register.
INCF
Increment f
IORWF
Inclusive OR W with f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) + 1 → (destination)
Operation:
(W) .OR. (f) → (destination)
Status Affected:
Z
Status Affected:
Z
Description:
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result
is placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
Description:
Inclusive OR the W register with
register ‘f’. If ‘d’ is ‘0’, the result is
placed in the W register. If ‘d’ is
‘1’, the result is placed back in
register ‘f’.
GOTO k
INCF f,d
© 2005 Microchip Technology Inc.
Preliminary
INCFSZ f,d
Inclusive OR literal with W
IORLW k
IORWF
f,d
DS41262A-page 197
PIC16F685/687/689/690
MOVF
Move f
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
MOVF f,d
MOVWF
Move W to f
Syntax:
[ label ]
MOVWF
Operands:
0 ≤ f ≤ 127
Operation:
(W) → (f)
f
Operation:
(f) → (dest)
Status Affected:
None
Status Affected:
Z
Description:
Description:
The contents of register ‘f’ is
moved to a destination dependent
upon the status of ‘d’. If d = 0,
destination is W register. If d = 1,
the destination is file register ‘f’
itself. d = 1 is useful to test a file
register since Status flag Z is
affected.
Move data from W register to
register ‘f’.
Words:
1
Cycles:
1
Words:
1
Cycles:
1
Example
MOVF
Example
MOVW
F
OPTION
Before Instruction
OPTION =
W
=
After Instruction
OPTION =
W
=
FSR, 0
0xFF
0x4F
0x4F
0x4F
After Instruction
W =
value in FSR
register
Z = 1
MOVLW
Move literal to W
NOP
No Operation
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 255
Operands:
None
Operation:
k → (W)
Operation:
No operation
Status Affected:
None
Status Affected:
None
Description:
The eight-bit literal ‘k’ is loaded into
W register. The “don’t cares” will
assemble as ‘0’s.
Description:
No operation.
Words:
1
Cycles:
1
Words:
1
Cycles:
1
Example
MOVLW k
Example
MOVLW
NOP
0x5A
After Instruction
W =
DS41262A-page 198
NOP
0x5A
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
RETFIE
Return from Interrupt
RETLW
Return with literal in W
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
0 ≤ k ≤ 255
Operation:
TOS → PC,
1 → GIE
Operation:
k → (W);
TOS → PC
Status Affected:
None
Status Affected:
None
Description:
Return from Interrupt. Stack is
POPed and Top-of-Stack (TOS) is
loaded in the PC. Interrupts are
enabled by setting Global
Interrupt Enable bit, GIE
(INTCON<7>). This is a two-cycle
instruction.
Description:
The W register is loaded with the
eight-bit literal ‘k’. The program
counter is loaded from the top of
the stack (the return address).
This is a two-cycle instruction.
Words:
1
Cycles:
2
Example
RETFIE
Words:
1
Cycles:
2
Example
CALL TABLE;W contains
table
;offset value
•
;W now has table value
•
•
ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2 ;
•
•
•
RETLW kn ; End of table
RETFIE
After Interrupt
PC =
GIE =
RETLW k
TABLE
TOS
1
Before Instruction
W = 0x07
After Instruction
W = value of k8
© 2005 Microchip Technology Inc.
RETURN
Return from Subroutine
Syntax:
[ label ]
Operands:
None
Operation:
TOS → PC
RETURN
Status Affected:
None
Description:
Return from subroutine. The stack
is POPed and the top of the stack
(TOS) is loaded into the program
counter. This is a two-cycle
instruction.
Preliminary
DS41262A-page 199
PIC16F685/687/689/690
RLF
Rotate Left f through Carry
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
See description below
Status Affected:
C
Description:
The contents of register ‘f’ are
rotated one bit to the left through
the Carry flag. If ‘d’ is ‘0’, the
result is placed in the W register.
If ‘d’ is ‘1’, the result is stored
back in register ‘f’.
RLF
C
Words:
1
Cycles:
1
Example
f,d
RLF
REG1,0
REG1
C
=
=
1110 0110
0
=
=
=
1110 0110
1100 1100
1
After Instruction
REG1
W
C
Syntax:
[ label ] SLEEP
Operands:
None
Operation:
00h → WDT,
0 → WDT prescaler,
1 → TO,
0 → PD
Status Affected:
TO, PD
Description:
The power-down Status bit, PD is
cleared. Time-out Status bit, TO
is set. Watchdog Timer and its
prescaler are cleared.
The processor is put into Sleep
mode with the oscillator stopped.
SUBLW
Subtract W from literal
Syntax:
[ label ] SUBLW k
Operands:
0 ≤ k ≤ 255
Operation:
k - (W) → (W)
Status Affected: C, DC, Z
Description:
The W register is subtracted (2’s
complement method) from the
eight-bit literal ‘k’. The result is
placed in the W register.
SUBWF
Subtract W from f
Rotate Right f through Carry
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
Enter Sleep mode
Register f
Before Instruction
RRF
SLEEP
RRF f,d
See description below
Status Affected:
C
Description:
The contents of register ‘f’ are
rotated one bit to the right through
the Carry flag. If ‘d’ is ‘0’, the
result is placed in the W register.
If ‘d’ is ‘1’, the result is placed
back in register ‘f’.
C
DS41262A-page 200
Syntax:
[ label ] SUBWF f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) - (W) → (destination)
Status Affected: C, DC, Z
Description:
Register f
Preliminary
Subtract (2’s complement method)
W register from register ‘f’. If ‘d’ is
‘0’, the result is stored in the W
register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
SWAPF
Swap Nibbles in f
Syntax:
[ label ] SWAPF f,d
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f<3:0>) → (destination<7:4>),
(f<7:4>) → (destination<3:0>)
Status Affected:
None
Description:
The upper and lower nibbles of
register ‘f’ are exchanged. If ‘d’ is
‘0’, the result is placed in the W
register. If ‘d’ is ‘1’, the result is
placed in register ‘f’.
XORLW
Exclusive OR literal with W
Syntax:
[ label ] XORLW k
Operands:
0 ≤ k ≤ 255
Operation:
(W) .XOR. k → (W)
Status Affected:
Z
Description:
The contents of the W register
are XOR’ed with the eight-bit
literal ‘k’. The result is placed in
the W register.
XORWF
Exclusive OR W with f
Syntax:
[ label ] XORWF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) .XOR. (f) → (destination)
Status Affected:
Z
Description:
Exclusive OR the contents of the
W register with register ‘f’. If ‘d’ is
‘0’, the result is stored in the W
register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
© 2005 Microchip Technology Inc.
f,d
Preliminary
DS41262A-page 201
PIC16F685/687/689/690
NOTES:
DS41262A-page 202
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
16.0
DEVELOPMENT SUPPORT
16.1
The PICmicro® microcontrollers are supported with a
full range of hardware and software development tools:
• Integrated Development Environment
- MPLAB® IDE Software
• Assemblers/Compilers/Linkers
- MPASMTM Assembler
- MPLAB C17 and MPLAB C18 C Compilers
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
- MPLAB C30 C Compiler
- MPLAB ASM30 Assembler/Linker/Library
• Simulators
- MPLAB SIM Software Simulator
- MPLAB dsPIC30 Software Simulator
• Emulators
- MPLAB ICE 2000 In-Circuit Emulator
- MPLAB ICE 4000 In-Circuit Emulator
• In-Circuit Debugger
- MPLAB ICD 2
• Device Programmers
- PRO MATE® II Universal Device Programmer
- PICSTART® Plus Development Programmer
- MPLAB PM3 Device Programmer
• Low-Cost Demonstration Boards
- PICDEMTM 1 Demonstration Board
- PICDEM.netTM Demonstration Board
- PICDEM 2 Plus Demonstration Board
- PICDEM 3 Demonstration Board
- PICDEM 4 Demonstration Board
- PICDEM 17 Demonstration Board
- PICDEM 18R Demonstration Board
- PICDEM LIN Demonstration Board
- PICDEM USB Demonstration Board
• Evaluation Kits
- KEELOQ® Evaluation and Programming Tools
- PICDEM MSC
- microID® Developer Kits
- CAN
- PowerSmart® Developer Kits
- Analog
MPLAB Integrated Development
Environment Software
The MPLAB IDE software brings an ease of software
development previously unseen in the 8/16-bit microcontroller market. The MPLAB IDE is a Windows®
based application that contains:
• An interface to debugging tools
- simulator
- programmer (sold separately)
- emulator (sold separately)
- in-circuit debugger (sold separately)
• A full-featured editor with color coded context
• A multiple project manager
• Customizable data windows with direct edit of
contents
• High-level source code debugging
• Mouse over variable inspection
• Extensive on-line help
The MPLAB IDE allows you to:
• Edit your source files (either assembly or C)
• One touch assemble (or compile) and download
to PICmicro emulator and simulator tools
(automatically updates all project information)
• Debug using:
- source files (assembly or C)
- mixed assembly and C
- machine code
MPLAB IDE supports multiple debugging tools in a
single development paradigm, from the cost effective
simulators, through low-cost in-circuit debuggers, to
full-featured emulators. This eliminates the learning
curve when upgrading to tools with increasing flexibility
and power.
16.2
MPASM Assembler
The MPASM assembler is a full-featured, universal
macro assembler for all PICmicro MCUs.
The MPASM assembler generates relocatable object
files for the MPLINK object linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol reference, absolute LST files that contain source lines and
generated machine code and COFF files for
debugging.
The MPASM assembler features include:
• Integration into MPLAB IDE projects
• User defined macros to streamline assembly code
• Conditional assembly for multi-purpose source
files
• Directives that allow complete control over the
assembly process
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 203
PIC16F685/687/689/690
16.3
MPLAB C17 and MPLAB C18
C Compilers
16.6
The MPLAB C17 and MPLAB C18 Code Development
Systems are complete ANSI C compilers for
Microchip’s PIC17CXXX and PIC18CXXX family of
microcontrollers. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use not found with other compilers.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
16.4
MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK object linker combines relocatable
objects created by the MPASM assembler and the
MPLAB C17 and MPLAB C18 C compilers. It can link
relocatable objects from precompiled libraries, using
directives from a linker script.
The MPLIB object librarian manages the creation and
modification of library files of precompiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:
• Efficient linking of single libraries instead of many
smaller files
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
16.5
MPLAB C30 C Compiler
MPLAB C30 is distributed with a complete ANSI C
standard library. All library functions have been validated and conform to the ANSI C library standard. The
library includes functions for string manipulation,
dynamic memory allocation, data conversion, timekeeping and math functions (trigonometric, exponential
and hyperbolic). The compiler provides symbolic
information for high-level source debugging with the
MPLAB IDE.
DS41262A-page 204
MPLAB ASM30 assembler produces relocatable
machine code from symbolic assembly language for
dsPIC30F devices. MPLAB C30 compiler uses the
assembler to produce it’s object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:
•
•
•
•
•
•
Support for the entire dsPIC30F instruction set
Support for fixed-point and floating-point data
Command line interface
Rich directive set
Flexible macro language
MPLAB IDE compatibility
16.7
MPLAB SIM Software Simulator
The MPLAB SIM software simulator allows code development in a PC hosted environment by simulating the
PICmicro series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any pin. The execution can be performed in Single-Step, Execute Until
Break or Trace mode.
The MPLAB SIM simulator fully supports symbolic
debugging using the MPLAB C17 and MPLAB C18
C Compilers, as well as the MPASM assembler. The
software simulator offers the flexibility to develop and
debug code outside of the laboratory environment,
making it an excellent, economical software
development tool.
16.8
The MPLAB C30 C compiler is a full-featured, ANSI
compliant, optimizing compiler that translates standard
ANSI C programs into dsPIC30F assembly language
source. The compiler also supports many command
line options and language extensions to take full
advantage of the dsPIC30F device hardware capabilities and afford fine control of the compiler code
generator.
MPLAB ASM30 Assembler, Linker
and Librarian
MPLAB SIM30 Software Simulator
The MPLAB SIM30 software simulator allows code
development in a PC hosted environment by simulating
the dsPIC30F series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any of the pins.
The MPLAB SIM30 simulator fully supports symbolic
debugging using the MPLAB C30 C Compiler and
MPLAB ASM30 assembler. The simulator runs in either
a Command Line mode for automated tasks, or from
MPLAB IDE. This high-speed simulator is designed to
debug, analyze and optimize time intensive DSP
routines.
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
16.9
MPLAB ICE 2000
High-Performance Universal
In-Circuit Emulator
16.11 MPLAB ICD 2 In-Circuit Debugger
The MPLAB ICE 2000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for
PICmicro microcontrollers. Software control of the
MPLAB ICE 2000 in-circuit emulator is advanced by
the MPLAB Integrated Development Environment,
which allows editing, building, downloading and source
debugging from a single environment.
The MPLAB ICE 2000 is a full-featured emulator system with enhanced trace, trigger and data monitoring
features. Interchangeable processor modules allow the
system to be easily reconfigured for emulation of different processors. The universal architecture of the
MPLAB ICE in-circuit emulator allows expansion to
support new PICmicro microcontrollers.
The MPLAB ICE 2000 in-circuit emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft® Windows 32-bit operating system were
chosen to best make these features available in a
simple, unified application.
16.10 MPLAB ICE 4000
High-Performance Universal
In-Circuit Emulator
The MPLAB ICE 4000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for
high-end PICmicro microcontrollers. Software control
of the MPLAB ICE in-circuit emulator is provided by the
MPLAB Integrated Development Environment, which
allows editing, building, downloading and source
debugging from a single environment.
The MPLAB ICD 4000 is a premium emulator system,
providing the features of MPLAB ICE 2000, but with
increased emulation memory and high-speed performance for dsPIC30F and PIC18XXXX devices. Its
advanced emulator features include complex triggering
and timing, up to 2 Mb of emulation memory and the
ability to view variables in real-time.
The MPLAB ICE 4000 in-circuit emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft Windows 32-bit operating system were
chosen to best make these features available in a
simple, unified application.
© 2005 Microchip Technology Inc.
Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a
powerful, low-cost, run-time development tool,
connecting to the host PC via an RS-232 or high-speed
USB interface. This tool is based on the Flash
PICmicro MCUs and can be used to develop for these
and other PICmicro microcontrollers. The MPLAB
ICD 2 utilizes the in-circuit debugging capability built
into the Flash devices. This feature, along with
Microchip’s In-Circuit Serial ProgrammingTM (ICSPTM)
protocol, offers cost effective in-circuit Flash debugging
from the graphical user interface of the MPLAB
Integrated Development Environment. This enables a
designer to develop and debug source code by setting
breakpoints, single-stepping and watching variables,
CPU status and peripheral registers. Running at full
speed enables testing hardware and applications in
real-time. MPLAB ICD 2 also serves as a development
programmer for selected PICmicro devices.
16.12 PRO MATE II Universal Device
Programmer
The PRO MATE II is a universal, CE compliant device
programmer with programmable voltage verification at
VDDMIN and VDDMAX for maximum reliability. It features
an LCD display for instructions and error messages
and a modular detachable socket assembly to support
various package types. In Stand-Alone mode, the
PRO MATE II device programmer can read, verify and
program PICmicro devices without a PC connection. It
can also set code protection in this mode.
16.13 MPLAB PM3 Device Programmer
The MPLAB PM3 is a universal, CE compliant device
programmer with programmable voltage verification at
VDDMIN and VDDMAX for maximum reliability. It features
a large LCD display (128 x 64) for menus and error
messages and a modular detachable socket assembly
to support various package types. The ICSP™ cable
assembly is included as a standard item. In
Stand-Alone mode, the MPLAB PM3 device programmer can read, verify and program PICmicro devices
without a PC connection. It can also set code protection
in this mode. MPLAB PM3 connects to the host PC via
an RS-232 or USB cable. MPLAB PM3 has high-speed
communications and optimized algorithms for quick
programming of large memory devices and incorporates an SD/MMC card for file storage and secure data
applications.
Preliminary
DS41262A-page 205
PIC16F685/687/689/690
16.14 PICSTART Plus Development
Programmer
16.17 PICDEM 2 Plus
Demonstration Board
The PICSTART Plus development programmer is an
easy-to-use, low-cost, prototype programmer. It connects to the PC via a COM (RS-232) port. MPLAB
Integrated Development Environment software makes
using the programmer simple and efficient. The
PICSTART Plus development programmer supports
most PICmicro devices up to 40 pins. Larger pin count
devices, such as the PIC16C92X and PIC17C76X,
may be supported with an adapter socket. The
PICSTART Plus development programmer is CE
compliant.
The PICDEM 2 Plus demonstration board supports
many 18, 28 and 40-pin microcontrollers, including
PIC16F87X and PIC18FXX2 devices. All the necessary hardware and software is included to run the demonstration programs. The sample microcontrollers
provided with the PICDEM 2 demonstration board can
be programmed with a PRO MATE II device programmer, PICSTART Plus development programmer, or
MPLAB ICD 2 with a Universal Programmer Adapter.
The MPLAB ICD 2 and MPLAB ICE in-circuit emulators
may also be used with the PICDEM 2 demonstration
board to test firmware. A prototype area extends the
circuitry for additional application components. Some
of the features include an RS-232 interface, a 2 x 16
LCD display, a piezo speaker, an on-board temperature
sensor, four LEDs and sample PIC18F452 and
PIC16F877 Flash microcontrollers.
16.15 PICDEM 1 PICmicro
Demonstration Board
The PICDEM 1 demonstration board demonstrates the
capabilities of the PIC16C5X (PIC16C54 to
PIC16C58A), PIC16C61, PIC16C62X, PIC16C71,
PIC16C8X, PIC17C42, PIC17C43 and PIC17C44. All
necessary hardware and software is included to run
basic demo programs. The sample microcontrollers
provided with the PICDEM 1 demonstration board can
be programmed with a PRO MATE II device programmer or a PICSTART Plus development programmer.
The PICDEM 1 demonstration board can be connected
to the MPLAB ICE in-circuit emulator for testing. A
prototype area extends the circuitry for additional application components. Features include an RS-232
interface, a potentiometer for simulated analog input,
push button switches and eight LEDs.
16.16 PICDEM.net Internet/Ethernet
Demonstration Board
The PICDEM.net demonstration board is an Internet/Ethernet demonstration board using the
PIC18F452 microcontroller and TCP/IP firmware. The
board supports any 40-pin DIP device that conforms to
the standard pinout used by the PIC16F877 or
PIC18C452. This kit features a user friendly TCP/IP
stack, web server with HTML, a 24L256 Serial
EEPROM for Xmodem download to web pages into
Serial EEPROM, ICSP/MPLAB ICD 2 interface connector, an Ethernet interface, RS-232 interface and a
16 x 2 LCD display. Also included is the book and
CD-ROM “TCP/IP Lean, Web Servers for Embedded
Systems,” by Jeremy Bentham
DS41262A-page 206
16.18 PICDEM 3 PIC16C92X
Demonstration Board
The PICDEM 3 demonstration board supports the
PIC16C923 and PIC16C924 in the PLCC package. All
the necessary hardware and software is included to run
the demonstration programs.
16.19 PICDEM 4 8/14/18-Pin
Demonstration Board
The PICDEM 4 can be used to demonstrate the capabilities of the 8, 14 and 18-pin PIC16XXXX and
PIC18XXXX MCUs, including the PIC16F818/819,
PIC16F87/88, PIC16F62XA and the PIC18F1320
family of microcontrollers. PICDEM 4 is intended to
showcase the many features of these low pin count
parts, including LIN and Motor Control using ECCP.
Special provisions are made for low-power operation
with the supercapacitor circuit and jumpers allow
on-board hardware to be disabled to eliminate current
draw in this mode. Included on the demo board are provisions for Crystal, RC or Canned Oscillator modes, a
five volt regulator for use with a nine volt wall adapter
or battery, DB-9 RS-232 interface, ICD connector for
programming via ICSP and development with MPLAB
ICD 2, 2 x 16 liquid crystal display, PCB footprints for
H-Bridge motor driver, LIN transceiver and EEPROM.
Also included are: header for expansion, eight LEDs,
four potentiometers, three push buttons and a prototyping area. Included with the kit is a PIC16F627A and
a PIC18F1320. Tutorial firmware is included along
with the User’s Guide.
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
16.20 PICDEM 17 Demonstration Board
The PICDEM 17 demonstration board is an evaluation
board that demonstrates the capabilities of several
Microchip microcontrollers, including PIC17C752,
PIC17C756A, PIC17C762 and PIC17C766. A programmed sample is included. The PRO MATE II device
programmer, or the PICSTART Plus development programmer, can be used to reprogram the device for user
tailored application development. The PICDEM 17
demonstration board supports program download and
execution from external on-board Flash memory. A
generous prototype area is available for user hardware
expansion.
16.21 PICDEM 18R PIC18C601/801
Demonstration Board
The PICDEM 18R demonstration board serves to assist
development of the PIC18C601/801 family of Microchip
microcontrollers. It provides hardware implementation
of both 8-bit Multiplexed/Demultiplexed and 16-bit
Memory modes. The board includes 2 Mb external
Flash memory and 128 Kb SRAM memory, as well as
serial EEPROM, allowing access to the wide range of
memory types supported by the PIC18C601/801.
16.22 PICDEM LIN PIC16C43X
Demonstration Board
The powerful LIN hardware and software kit includes a
series of boards and three PICmicro microcontrollers.
The small footprint PIC16C432 and PIC16C433 are
used as slaves in the LIN communication and feature
on-board LIN transceivers. A PIC16F874 Flash
microcontroller serves as the master. All three microcontrollers are programmed with firmware to provide
LIN bus communication.
16.24 PICDEM USB PIC16C7X5
Demonstration Board
The PICDEM USB Demonstration Board shows off the
capabilities of the PIC16C745 and PIC16C765 USB
microcontrollers. This board provides the basis for
future USB products.
16.25 Evaluation and
Programming Tools
In addition to the PICDEM series of circuits, Microchip
has a line of evaluation kits and demonstration software
for these products.
• KEELOQ evaluation and programming tools for
Microchip’s HCS Secure Data Products
• CAN developers kit for automotive network
applications
• Analog design boards and filter design software
• PowerSmart battery charging evaluation/
calibration kits
• IrDA® development kit
• microID development and rfLabTM development
software
• SEEVAL® designer kit for memory evaluation and
endurance calculations
• PICDEM MSC demo boards for Switching mode
power supply, high-power IR driver, delta sigma
ADC and flow rate sensor
Check the Microchip web page and the latest Product
Selector Guide for the complete list of demonstration
and evaluation kits.
16.23 PICkitTM 1 Flash Starter Kit
A complete “development system in a box”, the PICkit™
Flash Starter Kit includes a convenient multi-section
board for programming, evaluation and development of
8/14-pin Flash PIC® microcontrollers. Powered via USB,
the board operates under a simple Windows GUI. The
PICkit 1 Starter Kit includes the User’s Guide (on CD
ROM), PICkit 1 tutorial software and code for various
applications. Also included are MPLAB® IDE (Integrated
Development Environment) software, software and
hardware “Tips ‘n Tricks for 8-pin Flash PIC®
Microcontrollers” Handbook and a USB interface cable.
Supports all current 8/14-pin Flash PIC microcontrollers,
as well as many future planned devices.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 207
PIC16F685/687/689/690
NOTES:
DS41262A-page 208
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
17.0
ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings(†)
Ambient temperature under bias..........................................................................................................-40° to +125°C
Storage temperature ........................................................................................................................ -65°C to +150°C
Voltage on VDD with respect to VSS ................................................................................................... -0.3V to +6.5V
Voltage on MCLR with respect to Vss ............................................................................................... -0.3V to +13.5V
Voltage on all other pins with respect to VSS ........................................................................... -0.3V to (VDD + 0.3V)
Total power dissipation(1) ............................................................................................................................... 800 mW
Maximum current out of VSS pin ..................................................................................................................... 300 mA
Maximum current into VDD pin ........................................................................................................................ 250 mA
Input clamp current, IIK (VI < 0 or VI > VDD)...............................................................................................................± 20 mA
Output clamp current, IOK (Vo < 0 or Vo >VDD).........................................................................................................± 20 mA
Maximum output current sunk by any I/O pin.................................................................................................... 25 mA
Maximum output current sourced by any I/O pin .............................................................................................. 25 mA
Maximum current sunk by PORTA, PORTB and PORTC (combined) ............................................................ 200 mA
Maximum current sourced PORTA, PORTB and PORTC (combined)............................................................ 200 mA
Note 1:
Power dissipation is calculated as follows: PDIS = VDD x {IDD - ∑ IOH} + ∑ {(VDD - VOH) x IOH} + ∑(VOL x IOL).
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
Note:
Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100 Ω should be used when applying a “low” level to the MCLR pin, rather than
pulling this pin directly to VSS.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 209
PIC16F685/687/689/690
FIGURE 17-1:
PIC16F685/687/689/690 VOLTAGE-FREQUENCY GRAPH,
-40°C ≤ TA ≤ +125°C
5.5
5.0
4.5
VDD
(Volts)
4.0
3.5
3.0
2.5
2.0
0
4
8
10
12
16
20
Frequency (MHz)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
DS41262A-page 210
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
17.1
DC Characteristics: PIC16F685/687/689/690-I (Industrial)
PIC16F685/687/689/690-E (Extended)
DC CHARACTERISTICS
Param
No.
Sym
VDD
Characteristic
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Min
Typ†
Max Units
Conditions
2.0
3.0
4.5
—
—
—
5.5
5.5
5.5
V
V
V
FOSC < = 4 MHz
FOSC < = 10 MHz
FOSC < = 20 MHz
1.5*
—
—
V
Device in Sleep mode
V
See Section 14.2.1 “Power-On Reset
(POR)” for details.
Supply Voltage
D001
D001C
D001D
D002
VDR
RAM Data Retention
Voltage(1)
D003
VPOR
VDD Start Voltage to
ensure internal Power-on
Reset signal
—
VSS
—
D004
SVDD
VDD Rise Rate to ensure
internal Power-on Reset
signal
0.05*
—
—
D005
VBOR
VDD Voltage Required to 2.025
initiate a Brown-Out Reset
—
2.175
V/ms See Section 14.2.1 “Power-On Reset
(POR)” for details.
V
* These parameters are characterized but not tested.
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 211
PIC16F685/687/689/690
17.2
DC Characteristics: PIC16F685/687/689/690-I (Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
DC CHARACTERISTICS
Param
No.
D010
Conditions
Device Characteristics
Min
Typ†
Max
Units
VDD
Supply Current (IDD)
D011
D012
D013
D014
D015
D016
D017
D018
(1, 2)
—
9
TBD
μA
2.0
—
18
TBD
μA
3.0
—
35
TBD
μA
5.0
—
110
TBD
μA
2.0
—
190
TBD
μA
3.0
—
330
TBD
μA
5.0
—
220
TBD
μA
2.0
—
370
TBD
μA
3.0
—
0.6
TBD
mA
5.0
—
70
TBD
μA
2.0
—
140
TBD
μA
3.0
—
260
TBD
μA
5.0
—
180
TBD
μA
2.0
—
320
TBD
μA
3.0
—
580
TBD
μA
5.0
—
TBD
TBD
μA
2.0
—
TBD
TBD
μA
3.0
—
TBD
TBD
mA
5.0
—
340
TBD
μA
2.0
—
500
TBD
μA
3.0
—
0.8
TBD
mA
5.0
—
180
TBD
μA
2.0
—
320
TBD
μA
3.0
—
580
TBD
μA
5.0
—
2.1
TBD
mA
4.5
—
2.4
TBD
mA
5.0
Note
FOSC = 32 kHz
LP Oscillator mode
FOSC = 1 MHz
XT Oscillator mode
FOSC = 4 MHz
XT Oscillator mode
FOSC = 1 MHz
EC Oscillator mode
FOSC = 4 MHz
EC Oscillator mode
FOSC = 31 kHz
INTOSC mode
FOSC = 8 MHz
INTOSC mode
FOSC = 4 MHz
EXTRC mode
FOSC = 20 MHz
HS Oscillator mode
Legend: TBD = To Be Determined
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave,
from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this
peripheral is enabled. The peripheral Δ current can be determined by subtracting the base IDD or IPD
current from this limit. Max values should be used when calculating total current consumption.
4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is
measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
DS41262A-page 212
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
17.2
DC Characteristics: PIC16F685/687/689/690-I (Industrial) (Continued)
DC CHARACTERISTICS
Param
No.
D020
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
Conditions
Device Characteristics
Power-down Base
Current (IPD)(4)
D021
D022
D023
D024
D025
D026
D027
Min
Typ†
Max
Units
VDD
Note
WDT, BOR, Comparators, VREF and
T1OSC disabled
—
0.1
TBD
μA
2.0
—
0.4
TBD
μA
3.0
—
0.8
TBD
μA
5.0
—
0.3
TBD
μA
2.0
—
1.8
TBD
μA
3.0
—
8.4
TBD
μA
5.0
—
58
TBD
μA
3.0
—
109
TBD
μA
5.0
—
3.3
TBD
μA
2.0
—
6.1
TBD
μA
3.0
—
11.5
TBD
μA
5.0
—
58
TBD
μA
2.0
—
85
TBD
μA
3.0
—
138
TBD
μA
5.0
—
4.0
TBD
μA
2.0
—
4.6
TBD
μA
3.0
—
6.0
TBD
μA
5.0
—
1.2
TBD
nA
3.0
—
2.2
TBD
nA
5.0
—
TBD
TBD
μA
3.0
—
TBD
TBD
μA
5.0
WDT Current
BOR Current
Comparator Current(3)
CVREF Current
T1OSC Current
A/D Current
VP6 Current
Legend: TBD = To Be Determined
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave,
from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this
peripheral is enabled. The peripheral Δ current can be determined by subtracting the base IDD or IPD
current from this limit. Max values should be used when calculating total current consumption.
4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is
measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 213
PIC16F685/687/689/690
17.3
DC Characteristics: PIC16F685/687/689/690-E (Extended)
DC CHARACTERISTICS
Param
No.
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C for extended
Conditions
Device Characteristics
D010E Supply Current (IDD)
D011E
D012E
D013E
D014E
D015E
D016E
D017E
D018E
Min
Typ†
Max
Units
VDD
—
9
TBD
μA
2.0
—
18
TBD
μA
3.0
—
35
TBD
μA
5.0
—
110
TBD
μA
2.0
—
190
TBD
μA
3.0
—
330
TBD
μA
5.0
—
220
TBD
μA
2.0
—
370
TBD
μA
3.0
—
0.6
TBD
mA
5.0
—
70
TBD
μA
2.0
—
140
TBD
μA
3.0
—
260
TBD
μA
5.0
—
180
TBD
μA
2.0
—
320
TBD
μA
3.0
—
580
TBD
μA
5.0
—
TBD
TBD
μA
2.0
—
TBD
TBD
μA
3.0
—
TBD
TBD
mA
5.0
—
340
TBD
μA
2.0
—
500
TBD
μA
3.0
—
0.8
TBD
mA
5.0
—
180
TBD
μA
2.0
—
320
TBD
μA
3.0
—
580
TBD
μA
5.0
—
2.1
TBD
mA
4.5
—
2.4
TBD
mA
5.0
Note
FOSC = 32 kHz
LP Oscillator mode
FOSC = 1 MHz
XT Oscillator mode
FOSC = 4 MHz
XT Oscillator mode
FOSC = 1 MHz
EC Oscillator mode
FOSC = 4 MHz
EC Oscillator mode
FOSC = 31 kHz
INTOSC mode
FOSC = 8 MHz
INTOSC mode
FOSC = 4 MHz
EXTRC mode
FOSC = 20 MHz
HS Oscillator mode
Legend: TBD = To Be Determined
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave,
from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this
peripheral is enabled. The peripheral Δ current can be determined by subtracting the base IDD or IPD
current from this limit. Max values should be used when calculating total current consumption.
4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is
measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
DS41262A-page 214
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
17.3
DC Characteristics: PIC16F685/687/689/690-E (Extended)
DC CHARACTERISTICS
Param
No.
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C for extended
Conditions
Device Characteristics
D020E Power-down Base
Current (IPD)(4)
D021E
Min
Typ†
Max
Units
VDD
Note
WDT, BOR, Comparators, VREF and
T1OSC disabled
—
0.1
TBD
μA
2.0
—
0.4
TBD
μA
3.0
—
0.8
TBD
μA
5.0
—
0.3
TBD
μA
2.0
—
1.8
TBD
μA
3.0
—
8.4
TBD
μA
5.0
D022E
—
58
TBD
μA
3.0
—
109
TBD
μA
5.0
D023E
—
3.3
TBD
μA
2.0
D024E
D025E
D026E
D027E
—
6.1
TBD
μA
3.0
—
11.5
TBD
μA
5.0
—
58
TBD
μA
2.0
—
85
TBD
μA
3.0
—
138
TBD
μA
5.0
—
4.0
TBD
μA
2.0
—
4.6
TBD
μA
3.0
—
6.0
TBD
μA
5.0
—
1.2
TBD
nA
3.0
—
2.2
TBD
nA
5.0
—
TBD
TBD
μA
3.0
—
TBD
TBD
μA
5.0
WDT Current
BOR Current
Comparator Current(3)
CVREF Current
T1OSC Current
A/D Current(3)
VP6 Current
Legend: TBD = To Be Determined
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave,
from rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O
pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have
an impact on the current consumption.
3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this
peripheral is enabled. The peripheral Δ current can be determined by subtracting the base IDD or IPD
current from this limit. Max values should be used when calculating total current consumption.
4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is
measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 215
PIC16F685/687/689/690
17.4
DC Characteristics: PIC16F685/687/689/690-I (Industrial)
PIC16F685/687/689/690-E (Extended)
DC CHARACTERISTICS
Param
No.
Sym
VIL
Characteristic
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Min
Typ†
Max
Units
Vss
Vss
Conditions
—
0.8
V
4.5V ≤ VDD ≤ 5.5V
—
0.15 VDD
V
Otherwise
Vss
—
0.2 VDD
V
Entire range
V
Input Low Voltage
I/O port:
D030
with TTL buffer
D030A
D031
with Schmitt Trigger buffer
D032
MCLR, OSC1 (RC mode)
VSS
—
0.2 VDD
D033
OSC1 (XT and HS modes)(1)
VSS
—
0.3 VDD
V
D033A
OSC1 (LP mode)(1)
VSS
—
0.6 VDD
– 1.0
V
D0033B
OCS1 (ER mode)(1)
VSS
—
0.1 VDD
V
VIH
Input High Voltage
I/O port:
D040
D040A
with TTL buffer
D041
with Schmitt Trigger buffer
—
2.0
(0.25 VDD + 0.8)
—
—
VDD
VDD
V
V
4.5V ≤ VDD ≤ 5.5V
Otherwise
0.8 VDD
—
VDD
V
Entire range
D042
MCLR, PORTA
0.8 VDD
—
VDD
V
D043
OSC1 (XT, HS and LP modes)
0.7 VDD
—
VDD
V
D043A
OSC1 (ER mode)
0.9 VDD
—
VDD
V
50*
50*
250
250
400*
400*
μA
μA
VDD = 5.0V, VPIN = VSS
±1
μA
VSS ≤ VPIN ≤ VDD,
Pin at high-impedance
D070
IPUR
PORTA Weak Pull-up Current
PORTB Weak Pull-up Current
IIL
Input Leakage Current(2)
(Note 1)
(Note 1)
D060
I/O port
—
—
D061
MCLR(3)
—
—
±5
μA
VSS ≤ VPIN ≤ VDD
D063
OSC1
—
—
±5
μA
VSS ≤ VPIN ≤ VDD, XT, HS
and LP osc configuration
I/O port
—
—
0.6
V
IOL = 8.5 mA, VDD = 4.5V
OSC2/CLKOUT
—
—
0.6
V
IOL = 1.6 mA, VDD = 4.5V
VOL
D080
D083
*
†
Note 1:
2:
3:
4:
Output Low Voltage
These parameters are characterized but not tested.
Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external
clock in RC mode.
Negative current is defined as current sourced by the pin.
The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent
normal operating conditions. Higher leakage current may be measured at different input voltages.
See Section 10.0 “Data EEPROM and Flash Program Memory Control” for additional information.
DS41262A-page 216
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
17.4
DC Characteristics: PIC16F685/687/689/690-I (Industrial)
PIC16F685/687/689/690-E (Extended) (Continued)
DC CHARACTERISTICS
Param
No.
Sym
VOH
Characteristic
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Min
Typ†
Max
Units
Conditions
Output High Voltage
D090
I/O port
VDD – 0.7
—
—
V
IOH = -3.0 mA, VDD = 4.5V
D092
OSC2/CLKOUT
VDD – 0.7
—
—
V
IOH = -1.3 mA, VDD = 4.5V
—
200
—
nA
—
—
15*
pF
—
—
50*
pF
100K
1M
—
E/W
D100
IULP
Ultra Low-Power Wake-up
Current
Capacitive Loading Specs on
Output Pins
D100
COSC2 OSC2 pin
D101
CIO
All I/O pins
In XT, HS and LP modes when
external clock is used to drive
OSC1
Data EEPROM Memory
D120
ED
Byte Endurance
D120A
ED
Byte Endurance
10K
100K
—
E/W
D121
VDRW
VDD for Read/Write
VMIN
—
5.5
V
-40°C ≤ TA ≤ +85°C
+85°C ≤ TA ≤ +125°C
Using EECON1 to read/write
VMIN = Minimum operating
voltage
D122
TDEW
Erase/Write Cycle Time
—
5
6
ms
D123
TRETD
Characteristic Retention
40
—
—
Year
Provided no other
specifications are violated
D124
TREF
Number of Total Erase/Write
Cycles before Refresh(4)
1M
10M
—
E/W
-40°C ≤ TA ≤ +85°C
D130
EP
Cell Endurance
10K
100K
—
E/W
-40°C ≤ TA ≤ +85°C
D130A
ED
Cell Endurance
1K
10K
—
E/W
+85°C ≤ TA ≤ +125°C
D131
VPR
VDD for Read
VMIN
—
5.5
V
D132
VPEW
VDD for Erase/Write
4.5
—
5.5
V
D133
TPEW
Erase/Write cycle time
—
2
2.5
ms
D134
TRETD
Characteristic Retention
40
—
—
Year
Program Flash Memory
*
†
Note 1:
2:
3:
4:
VMIN = Minimum operating
voltage
Provided no other
specifications are violated
These parameters are characterized but not tested.
Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external
clock in RC mode.
Negative current is defined as current sourced by the pin.
The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent
normal operating conditions. Higher leakage current may be measured at different input voltages.
See Section 10.0 “Data EEPROM and Flash Program Memory Control” for additional information.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 217
PIC16F685/687/689/690
17.5
Timing Parameter Symbology
The timing parameter symbols have been created with
one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
T
Time
osc
OSC1
Lowercase letters (pp) and their meanings:
pp
cc
RC
ck
CLKOUT
rd
RD
cs
CS
rw
RD or WR
di
SDI
sc
SCK
do
SDO
ss
SS
dt
Data in
t0
T0CKI
io
I/O port
t1
T1CKI
mc
MCLR
wr
WR
Uppercase letters and their meanings:
S
F
Fall
P
Period
H
High
R
Rise
I
Invalid (High-impedance)
V
Valid
L
Low
Z
High-impedance
FIGURE 17-2:
LOAD CONDITIONS
Load Condition 1
Load Condition 2
VDD/2
RL
CL
Pin
CL
Pin
VSS
VSS
RL = 464Ω
CL = 50 pF
15 pF
DS41262A-page 218
for all pins
for OSC2 output
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
17.6
AC Characteristics: PIC16F685/687/689/690 (Industrial, Extended)
FIGURE 17-3:
EXTERNAL CLOCK TIMING
Q4
Q1
Q2
Q3
Q4
Q1
OSC1
1
3
4
3
4
2
CLKOUT
TABLE 17-1:
EXTERNAL CLOCK TIMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40°C ≤ TA ≤ +125°C
Param
No.
Sym
FOSC
1
2
3
4
TOSC
TCY
TosL,
TosH
TosR,
TosF
Characteristic
Min
Typ†
Max
Units
External CLKIN Frequency(1)
DC
DC
DC
DC
—
—
—
—
37
4
20
20
kHz
MHz
MHz
MHz
LP Oscillator mode
XT Oscillator mode
HS Oscillator mode
EC Oscillator mode
Oscillator Frequency(1)
—
TBD
—
0.1
1
8
—
32
—
—
—
4
—
4
20
MHz
MHz
kHz
MHz
MHz
INTOSC Oscillator mode
RC Oscillator mode
LP Oscillator mode
XT Oscillator mode
HS Oscillator mode
External CLKIN Period(1)
27
50
50
250
—
—
—
—
∞
∞
∞
∞
μs
ns
ns
ns
LP Oscillator mode
HS Oscillator mode
EC Oscillator mode
XT Oscillator mode
Oscillator Period(1)
—
—
250
250
50
31
125
—
—
—
—
—
TBD
10,000
1,000
μs
ns
ns
ns
ns
LP Oscillator mode
INTOSC Oscillator mode
RC Oscillator mode
XT Oscillator mode
HS Oscillator mode
Instruction Cycle Time(1)
External CLKIN (OSC1) High
External CLKIN Low
200
2*
20*
TCY
—
—
∞
—
—
ns
μs
ns
100 *
—
—
—
—
—
—
—
—
50*
25*
15*
ns
ns
ns
ns
TCY = 4/FOSC
LP oscillator, TOSC L/H duty cycle
HS oscillator, TOSC L/H duty cycle
XT oscillator, TOSC L/H duty cycle
LP oscillator
XT oscillator
HS oscillator
External CLKIN Rise
External CLKIN Fall
Conditions
Legend: TBD = To Be Determined
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and
are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on
characterization data for that particular oscillator type under standard operating conditions with the device executing
code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected
current consumption. All devices are tested to operate at ‘min’ values with an external clock applied to OSC1 pin.
When an external clock input is used, the ‘max’ cycle time limit is ‘DC’ (no clock) for all devices.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 219
PIC16F685/687/689/690
TABLE 17-2:
PRECISION INTERNAL OSCILLATOR PARAMETERS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40°C ≤ TA ≤ +125°C
Param
No.
F10
F14
Sym
FOSC
Characteristic
Internal Calibrated
INTOSC Frequency(1)
TIOSCST Oscillator Wake-up from
Sleep Start-up Time*
Freq
Min
Tolerance
Typ†
Max
Units
MHz VDD and Temperature TBD
MHz 2.5V ≤ VDD ≤ 5.5V
0°C ≤ TA ≤ +85°C
MHz 2.0V ≤ VDD ≤ 5.5V
-40°C ≤ TA ≤ +85°C (Ind.)
-40°C ≤ TA ≤ +125°C (Ext.)
μs VDD = 2.0V, -40°C to +85°C
μs VDD = 3.0V, -40°C to +85°C
μs VDD = 5.0V, -40°C to +85°C
±1%
±2%
—
—
8.00
8.00
TBD
TBD
±5%
—
8.00
TBD
—
—
—
—
—
—
TBD
TBD
TBD
TBD
TBD
TBD
Conditions
Legend: TBD = To Be Determined
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to
the device as possible. 0.1 μF and 0.01 μF values in parallel are recommended.
DS41262A-page 220
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 17-4:
CLKOUT AND I/O TIMING
Q1
Q4
Q2
Q3
OSC1
11
10
22
23
CLKOUT
13
12
19
14
18
16
I/O pin
(Input)
15
17
I/O pin
(Output)
New Value
Old Value
20, 21
TABLE 17-3:
CLKOUT AND I/O TIMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
Min
Typ†
Max
Units
Conditions
10
TOSH2CKL OSC1↑ to CLOUT↓
—
75
200
ns
(Note 1)
11
TOSH2CKH OSC1↑ to CLOUT↑
—
75
200
ns
(Note 1)
12
TCKR
CLKOUT Rise Time
—
35
100
ns
(Note 1)
13
TCKF
CLKOUT Fall Time
—
35
100
ns
(Note 1)
14
TCKL2IOV
CLKOUT↓ to Port Out Valid
—
—
20
ns
(Note 1)
TOSC + 200 ns
—
—
ns
(Note 1)
0
—
—
ns
(Note 1)
15
TIOV2CKH Port In Valid before CLKOUT↑
16
TCKH2IOI
17
TOSH2IOV OSC1↑ (Q1 cycle) to Port Out Valid
Port In Hold after CLKOUT↑
OSC1↑ (Q2 cycle) to Port Input
Invalid (I/O in hold time)
—
50
150*
ns
—
—
300
ns
100
—
—
ns
18
TOSH2IOI
19
TIOV2OSH Port Input Valid to OSC1↑
(I/O in setup time)
0
—
—
ns
20
TIOR
—
10
40
ns
21
TIOF
Port Output Fall Time
—
10
40
ns
22
TINP
INT Pin High or Low Time
25
—
—
ns
23
TRBP
PORTA change INT high or low
time
TCY
—
—
ns
Port Output Rise Time
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated.
Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 221
PIC16F685/687/689/690
FIGURE 17-5:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND
POWER-UP TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Time-out
Internal
Reset
Watchdog
Timer
Reset
34
31
34
I/O pins
FIGURE 17-6:
BROWN-OUT RESET TIMING AND CHARACTERISTICS
VDD
BVDD
(Device not in Brown-out Reset)
(Device in Brown-out Reset)
35
Reset (due to BOR)
Note 1:
64 ms Time-out(1)
64 ms delay only if PWRTE bit in the Configuration Word is programmed to ‘0’.
DS41262A-page 222
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 17-4:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature-40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
Min
Typ†
Max
Units
Conditions
30
TMCL
MCLR Pulse Width (low)
2
11
—
18
—
24
μs
ms
VDD = 5V, -40°C to +85°C
Extended temperature
31
TWDT
Watchdog Timer Time-out
Period (No Prescaler)
7
10
18
17
33
30
ms
ms
VDD = 5V, -40°C to +85°C
Extended temperature
32
TOST
Oscillation Start-up Timer
Period
—
1024TOSC
—
—
TOSC = OSC1 period
33*
TPWRT
Power-up Timer Period
28*
TBD
64
TBD
132*
TBD
ms
ms
VDD = 5V, -40°C to +85°C
Extended Temperature
34
TIOZ
I/O High-impedance from
MCLR Low or Watchdog Timer
Reset
—
—
2.0
μs
BVHY
Brown-out Reset Hysteresis
—
25
—
mV
BVDD
Brown-out Reset Voltage
2.025
—
2.175
V
TBOR
Brown-out Reset Pulse Width
100*
—
—
μs
35
VDD ≤ BVDD (D005)
Legend: TBD = To Be Determined
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 223
PIC16F685/687/689/690
FIGURE 17-7:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
40
41
42
T1CKI
45
46
48
47
TMR0 or
TMR1
TABLE 17-5:
Param
No.
40*
TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Sym
TT0H
Characteristic
T0CKI High Pulse Width
No Prescaler
With Prescaler
41*
TT0L
T0CKI Low Pulse Width
No Prescaler
With Prescaler
42*
TT0P
T0CKI Period
45*
TT1H
T1CKI High
Time
Synchronous, No Prescaler
Synchronous,
with Prescaler
Asynchronous
46*
TT1L
T1CKI Low Time Synchronous, No Prescaler
Synchronous,
with Prescaler
47*
Max
Units
0.5 TCY + 20
—
—
ns
10
—
—
ns
0.5 TCY + 20
—
—
ns
10
—
—
ns
Greater of:
20 or TCY + 40
N
—
—
ns
0.5 TCY + 20
—
—
ns
15
—
—
ns
30
—
—
ns
0.5 TCY + 20
—
—
ns
15
—
—
ns
Asynchronous
30
—
—
ns
Greater of:
30 or TCY + 40
N
—
—
ns
T1CKI Input
Period
FT1
Timer1 oscillator input frequency range
(oscillator enabled by setting bit T1OSCEN)
TCKEZTMR1 Delay from external clock edge to timer increment
*
†
Typ†
Synchronous
TT1P
Asynchronous
48
Min
60
—
—
ns
DC
—
200*
kHz
2 TOSC*
—
7 TOSC*
—
Conditions
N = prescale
value (2, 4, ...,
256)
N = prescale
value (1, 2, 4,
8)
These parameters are characterized but not tested.
Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS41262A-page 224
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 17-8:
CAPTURE/COMPARE/PWM+ TIMINGS (ECCP+)
CCP1
(Capture mode)
50
51
52
CCP1
(Compare or PWM mode)
53
Note:
TABLE 17-6:
54
Refer to Figure 17-2 for load conditions.
CAPTURE/COMPARE/PWM+ REQUIREMENTS (ECCP+)
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
Symbol
No.
50*
51*
52*
TccL
TccH
TccP
Characteristic
CCP1 Input Low Time
CCP1 Input High Time
Min
Typ† Max Units
No Prescaler
0.5TCY + 20
—
—
ns
With Prescaler
20
—
—
ns
No Prescaler
0.5TCY + 20
—
—
ns
With Prescaler
20
—
—
ns
3TCY + 40
N
—
—
ns
CCP1 Input Period
53*
TccR
CCP1 Output Rise Time
—
10
25
ns
54*
TccF
CCP1 Output Fall Time
—
10
25
ns
Conditions
N = prescale
value (1, 4 or
16)
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 225
PIC16F685/687/689/690
TABLE 17-7:
COMPARATOR SPECIFICATIONS
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Comparator Specifications
Param.
No.
C01
Sym
Characteristics
VOS
Input Offset Voltage
C02
VCM
Input Common Mode Voltage
C03
CMRR
Common Mode Rejection
Ratio
C04
TRT
C05
*
Note 1:
Max
Units
—
± 5.0
± 10
mV
0
—
VDD - 1.5
V
—
—
db
Response Time(1)
—
150
400*
ns
TMC2COV Comparator Mode Change to
Output Valid
—
—
10*
μs
Comments
These parameters are characterized but not tested.
Response time measured with one comparator input at (VDD - 1.5)/2 while the other input transitions from
VSS to VDD – 1.5V.
COMPARATOR VOLTAGE REFERENCE (CVREF) SPECIFICATIONS
Comparator Voltage Reference Specifications
CV01
Typ
+55*
TABLE 17-8:
Param
No.
Min
Symbol
Characteristics
Resolution
CVRES
CV02
Absolute Accuracy
CV03
Unit Resistor Value (R)
(1)
CV04
R Ladder Settling Time
CV05
VP6 Settling Time
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Min
Typ
Max
Units
VDD/24*
—
VDD/32*
LSb
—
—
—
—
±1/4*
±1/2*
LSb
LSb
—
2K*
—
Ω
—
—
10*
μs
TBD
TBD
TBD
Comments
Low Range (VRR = 1)
High Range (VRR = 0)
Legend: TBD = To Be Determined
* These parameters are characterized but not tested.
Note 1: Settling time measured while VRR = 1 and VR<3:0> transitions from 0000 to 1111.
TABLE 17-9:
VOLTAGE (VR) REFERENCE SPECIFICATIONS
VR Voltage Reference Specifications
Param
No.
Symbol
Characteristics
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Min
Typ
Max
Units
TBD
0.6
TBD
V
VR01
VROUT
VR voltage output
VR02
TCVOUT
Voltage drift temperature
coefficient
—
150
TBD
ppm/°C
VR03
ΔVROUT/
ΔVDD
Voltage drift with respect to
VDD regulation
—
200
—
μV/V
VR04
TSTABLE
Settling Time
—
10
100*
μs
Comments
Legend: TBD = To Be Determined
* These parameters are characterized but not tested.
DS41262A-page 226
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 17-9:
EUSART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RB7/TX/CK
pin
121
121
RB5/AN11/RX/DT
pin
120
Note:
122
Refer to Figure 17-2 for load conditions.
TABLE 17-10: EUSART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40°C ≤ TA ≤ +125°C
Param.
No.
120
121
122
Symbol
Characteristic
TCKH2DTV SYNC XMIT (Master & Slave)
Clock high to data-out valid
TCKRF
Clock out rise time and fall time (Master mode)
TDTRF
Data-out rise time and fall time
FIGURE 17-10:
Min
Max
Units
—
40
ns
—
—
20
20
ns
ns
Conditions
EUSART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
RC4/C2OUT/TX/CK
pin
RC5/RX/DT
pin
125
126
Note: Refer to Figure 17-2 for load conditions.
TABLE 17-11: EUSART SYNCHRONOUS RECEIVE REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param.
No.
125
126
Symbol
Characteristic
TDTV2CKL SYNC RCV (Master & Slave)
Data-hold before CK ↓ (DT hold time)
TCKL2DTL
Data-hold after CK ↓ (DT hold time)
© 2005 Microchip Technology Inc.
Preliminary
Min
Max
Units
10
—
ns
15
—
ns
Conditions
DS41262A-page 227
PIC16F685/687/689/690
FIGURE 17-11:
SPI™ MASTER MODE TIMING (CKE = 0, SMP = 0)
SS
70
SCK
(CKP = 0)
71
72
78
79
79
78
SCK
(CKP = 1)
80
bit 6 - - - - - -1
MSb
SDO
LSb
75, 76
SDI
MSb In
bit 6 - - - -1
LSb In
74
73
Note: Refer to Figure 17-2 for load conditions.
FIGURE 17-12:
SPI™ MASTER MODE TIMING (CKE = 1, SMP = 1)
SS
81
SCK
(CKP = 0)
71
72
79
73
SCK
(CKP = 1)
80
78
SDO
MSb
bit 6 - - - - - -1
LSb
bit 6 - - - -1
LSb In
75, 76
SDI
MSb In
74
Note: Refer to Figure 17-2 for load conditions.
DS41262A-page 228
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 17-13:
SPI™ SLAVE MODE TIMING (CKE = 0)
SS
70
SCK
(CKP = 0)
83
71
72
78
79
79
78
SCK
(CKP = 1)
80
MSb
SDO
LSb
bit 6 - - - - - -1
77
75, 76
SDI
MSb In
bit 6 - - - -1
LSb In
74
73
Note: Refer to Figure 17-2 for load conditions.
FIGURE 17-14:
SPI™ SLAVE MODE TIMING (CKE = 1)
82
SS
SCK
(CKP = 0)
70
83
71
72
SCK
(CKP = 1)
80
MSb
SDO
bit 6 - - - - - -1
LSb
75, 76
SDI
MSb In
77
bit 6 - - - -1
LSb In
74
Note: Refer to Figure 17-2 for load conditions.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 229
PIC16F685/687/689/690
TABLE 17-12: SPI™ MODE REQUIREMENTS
Param
No.
Symbol
70*
Characteristic
TSSL2SCH, SS↓ to SCK↓ or SCK↑ input
TSSL2SCL
Min
Typ†
Max Units Conditions
TCY
—
—
ns
71*
TSCH
SCK input high time (Slave mode)
TCY + 20
—
—
ns
72*
TSCL
SCK input low time (Slave mode)
TCY + 20
—
—
ns
73*
TDIV2SCH, Setup time of SDI data input to SCK edge
TDIV2SCL
100
—
—
ns
74*
TSCH2DIL,
TSCL2DIL
Hold time of SDI data input to SCK edge
100
—
—
ns
75*
TDOR
SDO data output rise time
—
10
25
ns
76*
TDOF
SDO data output fall time
3.0-5.5V
2.0-5.5V
—
25
50
ns
—
10
25
ns
77*
TSSH2DOZ
SS↑ to SDO output high-impedance
10
—
50
ns
78*
TSCR
SCK output rise time
(Master mode)
3.0-5.5V
—
10
25
ns
2.0-5.5V
—
25
50
ns
79*
TSCF
SCK output fall time (Master mode)
—
10
25
ns
80*
TSCH2DOV, SDO data output valid after
TSCL2DOV SCK edge
3.0-5.5V
—
—
50
ns
2.0-5.5V
—
—
145
ns
81*
TDOV2SCH, SDO data output setup to SCK edge
TDOV2SCL
Tcy
—
—
ns
82*
TSSL2DOV
—
—
50
ns
83*
TSCH2SSH, SS ↑ after SCK edge
TSCL2SSH
1.5TCY + 40
—
—
ns
SDO data output valid after SS↓ edge
* These parameters are characterized but not tested.
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
FIGURE 17-15:
I2C™ BUS START/STOP BITS TIMING
SCL
91
93
90
92
SDA
Stop
Condition
Start
Condition
Note: Refer to Figure 17-2 for load conditions.
DS41262A-page 230
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 17-13: I2C™ BUS START/STOP BITS REQUIREMENTS
Param
No.
Symbol
Characteristic
90*
TSU:STA
91*
THD:STA
92*
TSU:STO
93
THD:STO Stop condition
Start condition
Typ
4700
—
Max Units
—
Setup time
400 kHz mode
600
—
—
Start condition
100 kHz mode
4000
—
—
Hold time
400 kHz mode
600
—
—
Stop condition
100 kHz mode
4700
—
—
Setup time
Hold time
*
100 kHz mode
Min
400 kHz mode
600
—
—
100 kHz mode
4000
—
—
400 kHz mode
600
—
—
Conditions
ns
Only relevant for Repeated
Start condition
ns
After this period, the first
clock pulse is generated
ns
ns
These parameters are characterized but not tested.
FIGURE 17-16:
I2C™ BUS DATA TIMING
103
102
100
101
SCL
90
106
107
91
92
SDA
In
110
109
109
SDA
Out
Note: Refer to Figure 17-2 for load conditions.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 231
PIC16F685/687/689/690
TABLE 17-14: I2C™ BUS DATA REQUIREMENTS
Param.
No.
100*
Symbol
THIGH
Characteristic
Clock high time
Min
Max
Units
100 kHz mode
4.0
—
μs
Device must operate at a
minimum of 1.5 MHz
400 kHz mode
0.6
—
μs
Device must operate at a
minimum of 10 MHz
1.5TCY
—
100 kHz mode
4.7
—
μs
Device must operate at a
minimum of 1.5 MHz
400 kHz mode
1.3
—
μs
Device must operate at a
minimum of 10 MHz
SSP Module
101*
TLOW
Clock low time
SSP Module
102*
103*
90*
91*
106*
107*
92*
109*
110*
TR
TF
TSU:STA
THD:STA
THD:DAT
TSU:DAT
TSU:STO
TAA
TBUF
CB
*
Note 1:
2:
Conditions
1.5TCY
—
SDA and SCL rise
time
100 kHz mode
—
1000
ns
400 kHz mode
0.1CB
300
ns
SDA and SCL fall
time
100 kHz mode
—
300
ns
400 kHz mode
20 + 0.1CB
300
ns
CB is specified to be from
10-400 pF
Only relevant for
Repeated Start condition
20 +
100 kHz mode
4.7
—
μs
400 kHz mode
0.6
—
μs
Start condition hold 100 kHz mode
time
400 kHz mode
4.0
—
μs
0.6
—
μs
Data input hold time 100 kHz mode
0
—
ns
400 kHz mode
0
0.9
μs
100 kHz mode
250
—
ns
400 kHz mode
100
—
ns
Start condition
setup time
Data input setup
time
Stop condition
setup time
Output valid from
clock
Bus free time
100 kHz mode
4.7
—
μs
400 kHz mode
0.6
—
μs
100 kHz mode
—
3500
ns
400 kHz mode
—
—
ns
100 kHz mode
4.7
—
μs
400 kHz mode
1.3
—
μs
—
400
pF
Bus capacitive loading
CB is specified to be from
10-400 pF
After this period the first
clock pulse is generated
(Note 2)
(Note 1)
Time the bus must be free
before a new transmission
can start
These parameters are characterized but not tested.
As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region
(min. 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
A Fast mode (400 kHz) I2C bus device can be used in a Standard mode (100 kHz) I2C bus system, but the
requirement TSU:DAT ≥ 250 ns must then be met. This will automatically be the case if the device does not
stretch the low period of the SCL signal. If such a device does stretch the low period of the SCL signal, it
must output the next data bit to the SDA line TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the
Standard mode I2C bus specification), before the SCL line is released.
DS41262A-page 232
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TABLE 17-15: PIC16F685/687/689/690 A/D CONVERTER CHARACTERISTICS:
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
Min
Typ†
Max
Units
—
—
10 bits
bit
Conditions
A01
NR
Resolution
A03
EIL
Integral Error
—
—
±1
LSb VREF = 5.0V
A04
EDL
Differential Error
—
—
±1
LSb No missing codes to 10 bits
VREF = 5.0V
A05
EFS
Full-scale Range
2.2*
—
5.5*
A06
EOFF
Offset Error
—
—
±1
LSb VREF = 5.0V
A07
EGN
Gain Error
—
—
±1
LSb VREF = 5.0V
(1)
V
VSS ≤ VAIN ≤ VREF+
—
—
—
VDD + 0.3
V
VSS
—
VREF
V
Recommended
Impedance of
Analog Voltage
Source
—
—
10
kΩ
VREF Input
Current*(2)
—
—
±5
μA
During VAIN acquisition.
—
—
±150
μA
During A/D conversion cycle.
A10
—
Monotonicity
—
A20
VREF
Reference Voltage
2.0
A25
VAIN
Analog Input
Voltage
A30
ZAIN
A50
IREF
guaranteed
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: The A/D conversion result never decreases with an increase in the input voltage and has no missing
codes.
2: VREF current is from external VREF or VDD pin, whichever is selected as reference input.
3: When A/D is off, it will not consume any current other than leakage current. The power-down current
specification includes any such leakage from the A/D module.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 233
PIC16F685/687/689/690
FIGURE 17-17:
PIC16F685/687/689/690 A/D CONVERSION TIMING (NORMAL MODE)
BSF ADCON0, GO
134
1 TCY
(TOSC/2)(1)
131
Q4
130
A/D CLK
9
A/D Data
8
7
3
6
2
1
0
NEW_DATA
OLD_DATA
ADRES
1 TCY
ADIF
GO
DONE
Note 1:
Sampling Stopped
132
Sample
If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
TABLE 17-16: PIC16F685/687/689/690 A/D CONVERSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
Sym
Characteristic
130
TAD
A/D Clock Period
130
TAD
A/D Internal RC
Oscillator Period
131
TCNV
Conversion Time
(not including
Acquisition Time)(1)
132
TACQ
Acquisition Time
134
TGO
Q4 to A/D Clock
Start
Min
Typ†
Max
Units
Conditions
1.5
—
—
μs
3.0*
—
—
μs
TOSC-based, VREF full range
TOSC-based, VREF ≥ 2.5V
3.0*
6.0
9.0*
μs
ADCS<1:0> = 11 (RC mode)
At VDD = 2.5V
2.0*
4.0
6.0*
μs
At VDD = 5.0V
—
11
—
TAD
Set GO bit to new data in A/D Result
register
11.5
—
μs
5*
—
—
μs
The minimum time is the amplifier
settling time. This may be used if the
“new” input voltage has not changed
by more than 1 LSb (i.e., 4.1 mV @
4.096V) from the last sampled
voltage (as stored on CHOLD).
—
TOSC/2
—
—
If the A/D clock source is selected as
RC, a time of TCY is added before
the A/D clock starts. This allows the
SLEEP instruction to be executed.
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: ADRESH and ADRESL registers may be read on the following TCY cycle.
2: See Table 9-1 for minimum conditions.
DS41262A-page 234
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
FIGURE 17-18:
PIC16F685/687/689/690 A/D CONVERSION TIMING (SLEEP MODE)
BSF ADCON0, GO
134
(TOSC/2 + TCY)(1)
1 TCY
131
Q4
130
A/D CLK
9
A/D Data
8
7
6
3
2
0
NEW_DATA
OLD_DATA
ADRES
1
ADIF
1 TCY
GO
DONE
Note 1:
Sampling Stopped
132
Sample
If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
TABLE 17-17: PIC16F685/687/689/690 A/D CONVERSION REQUIREMENTS (SLEEP MODE)
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C ≤ TA ≤ +125°C
Param
No.
130
Sym
TAD
Characteristic
A/D Internal RC
Oscillator Period
Min
Typ†
Max
Units
Conditions
3.0*
6.0
9.0*
μs
ADCS<1:0> = 11 (RC mode)
At VDD = 2.5V
At VDD = 5.0V
2.0*
4.0
6.0*
μs
131
TCNV
Conversion Time
(not including
Acquisition Time)(1)
—
11
—
TAD
132
TACQ
Acquisition Time
(2)
11.5
—
μs
5*
—
—
μs
The minimum time is the amplifier
settling time. This may be used if
the “new” input voltage has not
changed by more than 1 LSb (i.e.,
4.1 mV @ 4.096V) from the last
sampled voltage (as stored on
CHOLD).
—
TOSC/2 + TCY
—
—
If the A/D clock source is selected
as RC, a time of TCY is added
before the A/D clock starts. This
allows the SLEEP instruction to be
executed.
134
TGO
Q4 to A/D Clock
Start
* These parameters are characterized but not tested.
† Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: ADRES register may be read on the following TCY cycle.
2: See Table 9-1 for minimum conditions.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 235
PIC16F685/687/689/690
NOTES:
DS41262A-page 236
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
18.0
DC AND AC
CHARACTERISTICS GRAPHS
AND TABLES
Graphs are not available at this time.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 237
PIC16F685/687/689/690
NOTES:
DS41262A-page 238
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
19.0
PACKAGING INFORMATION
19.1
Package Marking Information
20-Lead PDIP
Example
PIC16F685-I/P e3
0510017
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN
20-Lead SOIC (.300”)
Example
XXXXXXXXXXXXXX
XXXXXXXXXXXXXX
XXXXXXXXXXXXXX
PIC16F685-I
/SO e3
0510017
YYWWNNN
20-Lead SSOP
Example
XXXXXXXXXXX
XXXXXXXXXXX
YYWWNNN
PIC16F687
-I/SS e3
0510017
20-Lead QFN
Example
XXXXXXX
XXXXXXX
16F690
-I/ML e3
YYWWNNN
0510017
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 239
PIC16F685/687/689/690
19.2
Package Details
The following sections give the technical details of the packages.
20-Lead Plastic Dual In-line (P) – 300 mil Body (PDIP)
E1
D
2
n
α
1
E
A2
A
L
c
A1
β
B1
eB
p
B
Units
Dimension Limits
n
p
MIN
INCHES*
NOM
20
.100
.155
.130
MAX
MILLIMETERS
NOM
20
2.54
3.56
3.94
2.92
3.30
0.38
7.49
7.87
6.10
6.35
26.04
26.24
3.05
3.30
0.20
0.29
1.40
1.52
0.36
0.46
7.87
9.40
5
10
5
10
MIN
Number of Pins
Pitch
Top to Seating Plane
A
.140
.170
Molded Package Thickness
A2
.115
.145
Base to Seating Plane
A1
.015
Shoulder to Shoulder Width
E
.295
.310
.325
Molded Package Width
E1
.240
.250
.260
Overall Length
D
1.025
1.033
1.040
Tip to Seating Plane
L
.120
.130
.140
c
Lead Thickness
.008
.012
.015
Upper Lead Width
B1
.055
.060
.065
Lower Lead Width
B
.014
.018
.022
eB
Overall Row Spacing
§
.310
.370
.430
α
Mold Draft Angle Top
5
10
15
β
Mold Draft Angle Bottom
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-001
Drawing No. C04-019
DS41262A-page 240
Preliminary
MAX
4.32
3.68
8.26
6.60
26.42
3.56
0.38
1.65
0.56
10.92
15
15
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
20-Lead Plastic Small Outline (SO) – Wide, 300 mil Body (SOIC)
E
E1
p
D
2
B
n
1
h
α
45°
c
A2
A
φ
β
A1
L
Units
Dimension Limits
n
p
Number of Pins
Pitch
Overall Height
Molded Package Thickness
Standoff §
Overall Width
Molded Package Width
Overall Length
Chamfer Distance
Foot Length
Foot Angle
Lead Thickness
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
A
A2
A1
E
E1
D
h
L
φ
c
B
α
β
MIN
.093
.088
.004
.394
.291
.496
.010
.016
0
.009
.014
0
0
INCHES*
NOM
20
.050
.099
.091
.008
.407
.295
.504
.020
.033
4
.011
.017
12
12
MAX
.104
.094
.012
.420
.299
.512
.029
.050
8
.013
.020
15
15
MILLIMETERS
NOM
20
1.27
2.36
2.50
2.24
2.31
0.10
0.20
10.01
10.34
7.39
7.49
12.60
12.80
0.25
0.50
0.41
0.84
0
4
0.23
0.28
0.36
0.42
0
12
0
12
MIN
MAX
2.64
2.39
0.30
10.67
7.59
13.00
0.74
1.27
8
0.33
0.51
15
15
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-013
Drawing No. C04-094
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 241
PIC16F685/687/689/690
20-Lead Plastic Shrink Small Outline (SS) – 209 mil Body, 5.30 mm (SSOP)
E
E1
p
D
B
2
1
n
c
A2
A
f
L
Units
Dimension Limits
n
p
MIN
A1
INCHES
NOM
20
.026
.069
.307
.209
.283
.030
4°
-
MAX
MILLIMETERS*
NOM
20
0.65
1.65
1.75
0.05
7.40
7.80
5.00
5.30
.295
7.20
0.55
0.75
0.09
0°
4°
0.22
-
MIN
Number of Pins
Pitch
Overall Height
A
.079
Molded Package Thickness
A2
.065
.073
Standoff
A1
.002
Overall Width
E
.291
.323
Molded Package Width
E1
.197
.220
Overall Length
D
.272
.289
Foot Length
L
.022
.037
c
Lead Thickness
.004
.010
f
Foot Angle
0°
8°
Lead Width
B
.009
.015
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions
shall not exceed .010" (0.254mm) per side.
MAX
2.00
1.85
8.20
5.60
7.50
0.95
0.25
8°
0.38
JEDEC Equivalent: MO-150
Drawing No. C04-072
DS41262A-page 242
Revised 11/03/03
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
20-Lead Plastic Quad Flat No Lead Package (ML) 4x4x0.9 mm Body (QFN) – Saw Singulated
D
D1
EXPOSED
METAL
PAD
e
E1
E
2
b
1
n
OPTIONAL
INDEX
AREA
TOP VIEW
L
BOTTOM VIEW
A3
A
A1
Number of Pins
Pitch
Overall Height
Standoff
Contact Thickness
Overall Width
Exposed Pad Width
Overall Length
Exposed Pad Length
Contact Width
Contact Length
Units
Dimension Limits
n
e
A
A1
A3
E
E2
D
D2
b
L
MIN
.031
.000
.152
.100
.152
.100
.007
.012
INCHES
NOM
20
.020 BSC
.035
.001
.008 REF
.157
.106
.157
.106
.010
.016
MAX
.039
.002
.163
.110
.163
.110
.012
.020
MILLIMETERS*
NOM
20
0.50 BSC
0.80
0.90
0.00
0.02
0.20 REF
4.00
3.85
2.55
2.70
3.85
4.00
2.55
2.70
0.18
0.25
0.30
0.40
MIN
MAX
1.00
0.05
4.15
2.80
4.15
2.80
0.30
0.50
*Controlling Parameter
Notes:
JEDEC equivalent: Not Registered
Drawing No. C04-126
© 2005 Microchip Technology Inc.
Revised 04-24-05
Preliminary
DS41262A-page 243
PIC16F685/687/689/690
NOTES:
DS41262A-page 244
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
APPENDIX A:
DATA SHEET
REVISION HISTORY
APPENDIX B:
Revision A
This is a new data sheet.
This discusses some of the issues in migrating from
other PICmicro devices to the PIC16F6XX Family of
devices.
B.1
PIC16F676 to PIC16F685
TABLE B-1:
FEATURE COMPARISON
Feature
PIC16F676
PIC16F685
Max Operating Speed
20 MHz
20 MHz
1024
4096
Max Program
Memory (Words)
SRAM (bytes)
64
128
A/D Resolution
10-bit
10-bit
Data EEPROM
(Bytes)
128
256
Timers (8/16-bit)
1/1
2/1
Oscillator Modes
8
8
Brown-out Reset
Y
Y
Internal Pull-ups
RA0/1/2/4/5
RA0/1/2/4/5,
MCLR
Interrupt-on-change
RA0/1/2/3/4/5 RA0/1/2/3/4/5
Comparator
1
2
ECCP+
N
Y
Ultra Low-Power
Wake-Up
N
Y
Extended WDT
N
Y
Software Control
Option of WDT/BOR
N
Y
INTOSC Frequencies
4 MHz
31 kHz-8 MHz
N
Y
Clock Switching
Note:
© 2005 Microchip Technology Inc.
MIGRATING FROM
OTHER PICmicro®
DEVICES
Preliminary
This device has been designed to perform
to the parameters of its data sheet. It has
been tested to an electrical specification
designed to determine its conformance
with these parameters. Due to process
differences in the manufacture of this
device, this device may have different
performance characteristics than its earlier
version. These differences may cause this
device to perform differently in your
application than the earlier version of this
device.
DS41262A-page 245
PIC16F685/687/689/690
NOTES:
DS41262A-page 246
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
A
A/D ...................................................................................... 93
Acquisition Requirements ......................................... 100
Analog Port Pins ......................................................... 94
Associated registers.................................................. 103
Block Diagram............................................................. 93
Calculating Acquisition Time..................................... 100
Channel Selection....................................................... 94
Configuration and Operation....................................... 94
Configuring.................................................................. 99
Configuring Interrupt ................................................... 99
Conversion Clock........................................................ 94
Effects of a Reset...................................................... 103
Internal Sampling Switch (RSS) Impedance.............. 100
Operation During Sleep ............................................ 102
Output Format............................................................. 95
Reference Voltage (VREF)........................................... 94
Source Impedance.................................................... 100
Special Event Trigger................................................ 103
Specifications............................................ 233, 234, 235
Starting a Conversion ................................................. 95
Using the CCP Trigger.............................................. 103
Absolute Maximum Ratings .............................................. 209
AC Characteristics
Industrial and Extended ............................................ 219
Load Conditions ........................................................ 218
ACK pulse ......................................................................... 164
ADCON0 Register............................................................... 97
ADCON1 Register............................................................... 98
Analog-to-Digital Converter. See A/D
ANSEL Register .................................................................. 96
ANSELH Register ............................................................... 96
Assembler
MPASM Assembler................................................... 203
Auto-Wake-Up on RX Pin Falling Edge ............................ 146
B
BAUDCTL Register ........................................................... 134
BF bit................................................................................. 156
Block Diagrams
A/D .............................................................................. 93
Analog Input Model ................................................... 101
Capture Mode Operation .......................................... 114
Comparator 1 .............................................................. 80
Comparator 2 .............................................................. 82
Compare ................................................................... 114
EUSART Receive ..................................................... 144
EUSART Transmit .................................................... 142
Fail-Safe Clock Monitor (FSCM) ................................. 43
In-Circuit Serial Programming Connections.............. 191
Interrupt Logic ........................................................... 184
On-Chip Reset Circuit ............................................... 175
PIC16F685.................................................................... 5
PIC16F687/689............................................................. 6
PIC16F690.................................................................... 7
PWM (Enhanced)...................................................... 116
RA0 Pins ..................................................................... 51
RA1 Pins ..................................................................... 52
RA2 Pin....................................................................... 52
RA3 Pin....................................................................... 53
RA4 Pin....................................................................... 53
RA5 Pin....................................................................... 54
RB4 Pin....................................................................... 59
RB5 Pin....................................................................... 60
RB6 Pin....................................................................... 61
RB7 Pin....................................................................... 62
© 2005 Microchip Technology Inc.
RC0 and RC1 Pins ..................................................... 65
RC2 and RC3 Pins ..................................................... 65
RC4 Pin ...................................................................... 66
RC5 Pin ...................................................................... 66
RC6 Pin ...................................................................... 67
RC7 Pin ...................................................................... 67
Resonator Operation .................................................. 37
SSP (I2C Mode)........................................................ 164
SSP (SPI Mode) ....................................................... 155
Timer1 ........................................................................ 73
Timer2 ........................................................................ 78
TMR0/WDT Prescaler ................................................ 69
Watchdog Timer (WDT)............................................ 187
Break Character (12-bit) Transmit and Receive ............... 147
Brown-out Reset (BOR).................................................... 177
Associated ................................................................ 178
Specifications ........................................................... 223
Timing and Characteristics ....................................... 222
C
C Compilers
MPLAB C17.............................................................. 204
MPLAB C18.............................................................. 204
MPLAB C30.............................................................. 204
Capture Module. See Enhanced Capture/Compare/PWM+
(ECCP+)
CCP1CON Register.......................................................... 113
CCPR1H Register............................................................. 113
CCPR1L Register ............................................................. 113
CKE bit ............................................................................. 156
CKP bit ............................................................................. 157
Clock Accuracy with Asynchronous Operation ................. 131
CM1CON0 .......................................................................... 81
CM2CON0 Register............................................................ 83
CM2CON1 Register............................................................ 84
Code Examples
Assigning Prescaler to Timer0.................................... 71
Assigning Prescaler to WDT....................................... 71
Changing Between Capture Prescalers ................... 114
Indirect Addressing..................................................... 32
Initializing A/D............................................................. 99
Initializing PORTA ...................................................... 47
Initializing PORTB ...................................................... 56
Initializing PORTC ...................................................... 64
Loading the SSPBUF (SSPSR) Register ................. 158
Saving Status and W Registers in RAM ................... 186
Ultra Low-Power Wake-up Initialization...................... 50
Write Verify ............................................................... 111
Code Protection ................................................................ 190
Comparator Module ............................................................ 79
C1 Output State Versus Input Conditions................... 79
C2 Output State Versus Input Conditions................... 82
Comparator Voltage Reference (CVREF)............................ 89
Accuracy/Error............................................................ 89
Associated registers ................................................... 92
Configuring ................................................................. 89
Effects of a Reset ....................................................... 92
Response Time .......................................................... 92
Specifications ........................................................... 226
Comparators
Associated Registers.................................................. 92
C2OUT as T1 Gate..................................................... 74
Effects of a Reset ....................................................... 92
Operation During Sleep .............................................. 92
Response Time .......................................................... 92
Specifications ........................................................... 226
Preliminary
DS41262A-page 247
PIC16F685/687/689/690
Compare Module. See Enhanced Capture/Compare/PWM+
(ECCP+)
CONFIG Register.............................................................. 174
Configuration Bits.............................................................. 174
CPU Features ................................................................... 173
Customer Change Notification Service ............................. 253
Customer Notification Service........................................... 253
Customer Support ............................................................. 253
D
D/A bit ............................................................................... 156
Data EEPROM Memory .................................................... 105
Associated Registers ................................................ 112
Code Protection ........................................................ 111
Reading..................................................................... 108
Writing ....................................................................... 108
Data Memory....................................................................... 16
Data/Address bit (D/A) ...................................................... 156
DC Characteristics
Extended ................................................................... 214
Industrial ................................................................... 212
Industrial and Extended .................................... 211, 216
Demonstration Boards
PICDEM 1 ................................................................. 206
PICDEM 17 ............................................................... 207
PICDEM 18R ............................................................ 207
PICDEM 2 Plus ......................................................... 206
PICDEM 3 ................................................................. 206
PICDEM 4 ................................................................. 206
PICDEM LIN ............................................................. 207
PICDEM USB............................................................ 207
PICDEM.net Internet/Ethernet .................................. 206
Development Support ....................................................... 203
Device Overview ................................................................... 5
E
ECCP+. See Enhanced Capture/Compare/PWM+ (ECCP+)
ECCPAS Register ............................................................. 127
EEADR Register ............................................................... 106
EEADR Registers.............................................................. 105
EEADRH Registers ................................................... 105, 106
EECON1 Register ..................................................... 105, 107
EECON2 Register ............................................................. 105
EEDAT Register................................................................ 106
EEDATH Register ............................................................. 106
EEPROM Data Memory
Avoiding Spurious Write............................................ 111
Write Verify ............................................................... 111
Electrical Specifications .................................................... 209
Enhanced Capture/Compare/PWM+ (ECCP+) ................. 113
Associated registers.................................................. 130
Associated registers w/ Capture/Compare/Timer1 ... 115
Capture Mode ........................................................... 114
Prescaler........................................................... 114
CCP1 Pin Configuration ............................................ 114
Compare Mode ......................................................... 114
CCP1 Pin Configuration.................................... 115
Software Interrupt Mode ................................... 115
Special Event Trigger and A/D Conversions..... 115
Timer1 Mode Selection ..................................... 115
Enhanced PWM Mode .............................................. 116
Auto-restart ....................................................... 128
Auto-shutdown .......................................... 127, 128
Direction Change in Full-Bridge Output Mode .. 121
Duty Cycle......................................................... 117
Effects of Reset................................................. 129
DS41262A-page 248
Example PWM Frequencies and Resolutions .. 117
Full-Bridge Application Example....................... 121
Full-Bridge Mode .............................................. 120
Half-Bridge Application Examples .................... 119
Half-Bridge Mode.............................................. 119
Operation in Power-Managed Modes ............... 129
Operation with Fail-Safe Clock Monitor ............ 129
Output Configurations....................................... 116
Output Relationships (Active-High and
Active-Low)............................................... 118
Output Relationships Diagram.......................... 118
Period ............................................................... 117
Programmable Dead Band Delay..................... 126
Setup for Operation .......................................... 129
Shoot-through Current ...................................... 126
Start-up Considerations .................................... 128
TMR2 to PR2 Match ........................................... 77
Specifications ........................................................... 225
Timer Resources ...................................................... 113
Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) .............................. 131
Errata .................................................................................... 4
EUSART
Asynchronous Mode ................................................. 141
12-bit Break Transmit and Receive .................. 147
Associated Registers, Receive......................... 145
Associated Registers, Transmit ........................ 143
Auto-Wake-Up on Falling Edge ........................ 146
Receiver ........................................................... 144
Setting up 9-bit Mode with Address Detect ...... 144
Baud Rate Generator (BRG)
Auto-Baud Detect ............................................. 139
Baud Rate Error, Calculating............................ 135
Baud Rates, Asynchronous Modes .................. 137
Formulas........................................................... 135
High Baud Rate Select (BRGH Bit) .................. 135
Sampling........................................................... 135
Serial Port Enable (SPEN Bit) .................................. 131
Synchronous Master Mode....................................... 148
Associated Registers, Reception...................... 151
Associated Registers, Transmit ........................ 149
Reception ......................................................... 150
Requirements, Synchronous Receive .............. 227
Requirements, Synchronous Transmission...... 227
Timing Diagram, Synchronous Receive ........... 227
Timing Diagram, Synchronous Transmission... 227
Transmission .................................................... 148
Synchronous Slave Mode......................................... 152
Associated Registers, Receive......................... 153
Associated Registers, Transmit ........................ 152
Reception ......................................................... 153
Transmission .................................................... 152
Evaluation and Programming Tools.................................. 207
F
Fail-Safe Clock Monitor ...................................................... 43
Fail-Safe Condition Clearing....................................... 43
Fail-Safe Detection ..................................................... 43
Fail-Safe Operation..................................................... 43
Reset or Wake-up from Sleep .................................... 43
Firmware Instructions ....................................................... 193
Flash Program Memory .................................................... 105
Fuses. See Configuration Bits
G
General Purpose Register File ........................................... 16
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
I
I2C Mode
Addressing ................................................................ 165
Associated Registers ................................................ 172
Master Mode ............................................................. 171
Mode Selection ......................................................... 164
Multi-Master Mode .................................................... 171
Operation .................................................................. 164
Reception.................................................................. 166
Slave Mode
SCL and SDA pins ............................................ 164
Transmission............................................................. 169
ID Locations ...................................................................... 190
In-Circuit Serial Programming (ICSP) ............................... 190
Indirect Addressing, INDF and FSR registers ..................... 32
Instruction Format ............................................................. 193
Instruction Set ................................................................... 193
ADDLW ..................................................................... 195
ADDWF..................................................................... 195
ANDLW ..................................................................... 195
ANDWF..................................................................... 195
BCF........................................................................... 195
BSF ........................................................................... 195
BTFSC ...................................................................... 195
BTFSS ...................................................................... 196
CALL ......................................................................... 196
CLRF......................................................................... 196
CLRW ....................................................................... 196
CLRWDT................................................................... 196
COMF ....................................................................... 196
DECF ........................................................................ 196
DECFSZ.................................................................... 197
GOTO ....................................................................... 197
INCF.......................................................................... 197
INCFSZ ..................................................................... 197
IORLW ...................................................................... 197
IORWF ...................................................................... 197
MOVF........................................................................ 198
MOVLW .................................................................... 198
MOVWF .................................................................... 198
NOP .......................................................................... 198
RETFIE ..................................................................... 199
RETLW ..................................................................... 199
RETURN ................................................................... 199
RLF ........................................................................... 200
RRF........................................................................... 200
SLEEP ...................................................................... 200
SUBLW ..................................................................... 200
SUBWF ..................................................................... 200
SWAPF ..................................................................... 201
XORLW..................................................................... 201
XORWF..................................................................... 201
INTCON Register ................................................................ 26
Inter-Integrated Circuit (I2C). See I2C Mode
Internal Oscillator Block
INTOSC
Specifications.................................................... 220
Internal Sampling Switch (RSS) Impedance ...................... 100
Internet Address................................................................ 253
Interrupts ........................................................................... 183
A/D .............................................................................. 99
Associated Registers ................................................ 185
Capture ..................................................................... 114
Compare ................................................................... 114
Context Saving.......................................................... 186
Interrupt-on-Change.................................................... 49
© 2005 Microchip Technology Inc.
Interrupt-on-change .................................................... 56
PORTA/PORTB Interrupt-on-Change ...................... 184
RA2/INT.................................................................... 183
TMR0........................................................................ 183
TMR1.......................................................................... 74
TMR2 to PR2 Match ................................................... 78
TMR2 to PR2 Match (PWM)....................................... 77
INTOSC Specifications ..................................................... 220
IOCA Register..................................................................... 49
IOCB Register..................................................................... 58
L
Load Conditions................................................................ 218
M
MCLR ............................................................................... 176
Internal...................................................................... 176
Memory Organization ......................................................... 15
Data ............................................................................ 16
Program...................................................................... 15
Microchip Internet Web Site.............................................. 253
Migrating from other PICmicro Devices ............................ 245
MPLAB ASM30 Assembler, Linker, Librarian ................... 204
MPLAB ICD 2 In-Circuit Debugger ................................... 205
MPLAB ICE 2000 High-Performance Universal
In-Circuit Emulator.................................................... 205
MPLAB ICE 4000 High-Performance Universal
In-Circuit Emulator.................................................... 205
MPLAB Integrated Development Environment Software.. 203
MPLAB PM3 Device Programmer .................................... 205
MPLINK Object Linker/MPLIB Object Librarian ................ 204
O
OPCODE Field Descriptions............................................. 193
OPTION Register.......................................................... 25, 70
OSCCON Register.............................................................. 45
Oscillator
Associated registers ................................................... 45
Oscillator Configurations..................................................... 35
Oscillator Specifications.................................................... 219
Oscillator Start-up Timer (OST)
Specifications ........................................................... 223
Oscillator Switching
Fail-Safe Clock Monitor .............................................. 43
Two-Speed Clock Start-up ......................................... 41
P
P (Stop) bit........................................................................ 156
P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/PWM
(ECCP) ..................................................................... 116
Packaging ......................................................................... 239
Marking..................................................................... 239
PDIP Details ............................................................. 240
PCL and PCLATH............................................................... 32
Computed GOTO ....................................................... 32
Stack........................................................................... 32
PCON Register ................................................................. 178
PICkit 1 Flash Starter Kit .................................................. 207
PICSTART Plus Development Programmer..................... 206
PIE1 Register ..................................................................... 27
PIE2 Register ..................................................................... 28
Pin Diagram ...................................................................... 2, 3
PIR1 Register ..................................................................... 29
PIR2 Register ..................................................................... 30
PORTA
Additional Pin Functions ............................................. 47
Preliminary
DS41262A-page 249
PIC16F685/687/689/690
Interrupt-on-Change............................................ 49
Ultra Low-Power Wake-up ............................ 47, 50
Weak Pull-up....................................................... 47
Associated Registers .................................................. 55
Pin Descriptions and Diagrams................................... 51
RA0 ............................................................................. 51
RA1 ............................................................................. 52
RA2 ............................................................................. 52
RA3 ............................................................................. 53
RA4 ............................................................................. 53
RA5 ............................................................................. 54
Registers ..................................................................... 47
Specifications ............................................................ 221
PORTA Register ................................................................. 47
PORTB
Additional Pin Functions ............................................. 56
Weak Pull-up....................................................... 56
Associated Registers .................................................. 63
Interrupt-on-change .................................................... 56
Pin Descriptions and Diagrams................................... 59
RB4 ............................................................................. 59
RB5 ............................................................................. 60
RB6 ............................................................................. 61
RB7 ............................................................................. 62
Registers ..................................................................... 56
PORTB Register ................................................................. 57
PORTC................................................................................ 64
Associated Registers .................................................. 45
Associated registers.................................................... 68
P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/
PWM+ (ECCP+).................................................. 64
RC0 ............................................................................. 65
RC1 ............................................................................. 65
RC2 ............................................................................. 65
RC3 ............................................................................. 65
RC4 ............................................................................. 66
RC5 ............................................................................. 66
RC6 ............................................................................. 67
RC7 ............................................................................. 67
Registers ..................................................................... 64
Specifications ............................................................ 221
PORTC Register ................................................................. 64
Power-Down Mode (Sleep) ............................................... 189
Power-on Reset (POR) ..................................................... 176
Power-up Timer (PWRT)................................................... 176
Specifications ............................................................ 223
Precision Internal Oscillator Parameters........................... 220
Prescaler
Shared WDT/Timer0 ................................................... 71
Switching Prescaler Assignment................................. 71
PRO MATE II Universal Device Programmer ................... 205
Program Memory ................................................................ 15
Map and Stack ............................................................ 15
Programming, Device Instructions .................................... 193
PSTRCON Register .......................................................... 123
Pulse Steering................................................................... 123
PWM (ECCP+ Module)
Pulse Steering........................................................... 123
PWM Steering Operation Table ................................ 124
Steering Synchronization .......................................... 125
PWM Mode. See Enhanced Capture/Compare/PWM ...... 116
PWM Steering ................................................................... 124
PWM1CON Register ......................................................... 126
R
RCREG............................................................................. 144
RCSTA Register ............................................................... 133
SPEN Bit................................................................... 131
Reader Response............................................................. 254
Read-Write-Modify Operations ......................................... 193
Receive Overflow Indicator bit (SSPOV) .......................... 157
Register
RCREG Register ...................................................... 139
Registers
ADCON0 (A/D Control 0)............................................ 97
ADCON1 (A/D Control 1)............................................ 98
ANSEL (Analog Select) .............................................. 96
ANSELH (Analog Select High) ................................... 96
BAUDCTL (Baud Rate Control) ................................ 134
CCP1CON (Enhanced CCP Operation) ................... 113
CCPR1H ................................................................... 113
CCPR1L ................................................................... 113
CM1CON0 (C1 Control).............................................. 81
CM2CON0 (C2 Control).............................................. 83
CM2CON1 (C2 Control).............................................. 84
CONFIG (Configuration Word) ................................. 174
ECCPAS (Enhanced CCP Auto-shutdown Control) . 127
EEADR (EEPROM Address) .................................... 106
EEADRH (EEPROM Address).................................. 106
EECON1 (EEPROM Control 1) ................................ 107
EEDAT (EEPROM Data) .......................................... 106
EEDATH (EEPROM Data)........................................ 106
INTCON (Interrupt Control)......................................... 26
IOCA (Interrupt-on-change PORTA)........................... 49
IOCB (Interrupt-on-change PORTB)........................... 58
OPTION_REG ...................................................... 25, 70
OSCCON (Oscillator Control) ..................................... 45
PCON (Power Control) ....................................... 31, 178
PIE1 (Peripheral Interrupt Enable 1)........................... 27
PIE2 (Peripheral Interrupt Enable Register 2) ............ 28
PIR1 (Peripheral Interrupt Request Register 1).......... 29
PIR2 (Peripheral Interrupt Request Register 2).......... 30
PORTA ....................................................................... 47
PORTB ....................................................................... 57
PORTC ....................................................................... 64
PSTRCON (Pulse Steering Control)......................... 123
PWM1CON (Enhanced PWM Configuration) ........... 126
RCSTA (Receive Status and Control) ...................... 133
Reset Values ............................................................ 180
Reset Values (special registers) ............................... 182
Special Function Register Map
PIC16F685 ......................................................... 17
PIC16F687/689 .................................................. 18
PIC16F690 ......................................................... 19
Special Function Registers ......................................... 16
Special Register Summary
Bank 0 ................................................................ 20
Bank 1 ................................................................ 21
Bank 2 ................................................................ 22
Bank 3 ................................................................ 23
SRCON (SR Latch Control) ........................................ 87
SSPCON (Sync Serial Port Control) Register .......... 157
SSPMSK (SSP Mask)............................................... 167
SSPSTAT (Sync Serial Port Status) Register........... 156
Status ......................................................................... 24
T1CON (Timer1 Control) ............................................ 75
T2CON (Timer2 Control) ............................................ 77
TRISA (Tri-state PORTA) ........................................... 48
TRISB (Tri-state PORTB) ........................................... 57
TRISC (Tri-state PORTC)........................................... 64
R/W bit .............................................................................. 156
DS41262A-page 250
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
TXSTA (Transmit Status and Control) ...................... 132
VRCON (Voltage Reference Control) ......................... 90
WDTCON (Watchdog Timer Control) ....................... 188
WPUA (Weak Pull-up PORTA) ................................... 48
WPUB (Weak Pull-up PORTB) ................................... 57
Reset................................................................................. 175
Revision History ................................................................ 245
S
S (Start) bit ........................................................................ 156
Shoot-through Current ...................................................... 126
Slave Select Synchronization ........................................... 161
SMP bit ............................................................................. 156
Software Simulator (MPLAB SIM)..................................... 204
Software Simulator (MPLAB SIM30)................................. 204
SPBRG ............................................................................. 135
SPBRGH ........................................................................... 135
Special Event Trigger........................................................ 103
Special Function Registers ................................................. 16
SPI Mode .................................................................. 155, 161
Associated Registers ................................................ 163
Bus Mode Compatibility ............................................ 163
Effects of a Reset...................................................... 163
Enabling SPI I/O ....................................................... 159
Master Mode ............................................................. 160
Master/Slave Connection.......................................... 159
Serial Clock (SCK pin) .............................................. 155
Serial Data In (SDI pin) ............................................. 155
Serial Data Out (SDO pin) ........................................ 155
Slave Select .............................................................. 155
Slave Select Synchronization ................................... 161
Sleep Operation ........................................................ 163
SPI Clock .................................................................. 160
Typical Connection ................................................... 159
SRCON Register................................................................. 87
SSP
Overview
SPI Master/Slave Connection ................................... 159
SSP I2C Operation ............................................................ 164
Slave Mode ............................................................... 164
SSP Module
Clock Synchronization and the CKP Bit.................... 171
SPI Master Mode ...................................................... 160
SPI Slave Mode ........................................................ 161
SSPBUF.................................................................... 160
SSPSR...................................................................... 160
SSPCON Register ............................................................ 157
SSPEN bit ......................................................................... 157
SSPM bits ......................................................................... 157
SSPMSK Register............................................................. 167
SSPOV bit ......................................................................... 157
SSPSTAT Register ........................................................... 156
Status Register ................................................................... 24
Synchronous Serial Port Enable bit (SSPEN)................... 157
Synchronous Serial Port Mode Select bits (SSPM) .......... 157
Synchronous Serial Port. See SSP
T
T1CON Register ................................................................. 75
Time-out Sequence........................................................... 178
Timer0 ................................................................................. 69
Associated Registers .................................................. 71
External Clock............................................................. 70
External Clock Requirements ................................... 224
Interrupt....................................................................... 69
Operation .................................................................... 69
© 2005 Microchip Technology Inc.
T0CKI ......................................................................... 70
Timer1 ................................................................................ 73
Associated registers ................................................... 76
Asynchronous Counter Mode ..................................... 76
Reading and Writing ........................................... 76
External Clock Requirements ................................... 224
Interrupt ...................................................................... 74
Modes of Operations .................................................. 74
Operation During Sleep .............................................. 76
Oscillator..................................................................... 76
Prescaler .................................................................... 74
Timer1 Gate
Inverting Gate ..................................................... 74
Selecting Source ................................................ 74
TMR1H Register......................................................... 73
TMR1L Register ......................................................... 73
Timer2 ................................................................................ 77
Associated Registers.................................................. 78
Operation.................................................................... 77
Postscaler................................................................... 77
PR2 Register .............................................................. 77
Prescaler .................................................................... 77
TMR2 Register ........................................................... 77
TMR2 to PR2 Match Interrupt............................... 77, 78
Timing Diagrams
A/D Conversion ........................................................ 234
A/D Conversion (Sleep Mode).................................. 235
Asynchronous Reception.......................................... 145
Asynchronous Transmission .................................... 142
Asynchronous Transmission (Back to Back) ............ 142
Automatic Baud Rate Calculator .............................. 140
Auto-Wake-up Bit (WUE) During Normal Operation. 146
Auto-Wake-Up Bit (WUE) During Sleep ................... 146
Brown-out Reset (BOR)............................................ 222
Brown-out Reset Situations ...................................... 177
CLKOUT and I/O ...................................................... 221
Clock Synchronization .............................................. 172
Enhanced Capture/Compare/PWM (ECCP)............. 225
EUSART Synchronous Receive (Master/Slave)....... 227
EUSART Synchronous Transmission (Master/Slave) ....
227
External Clock .......................................................... 219
Fail-Safe Clock Monitor (FSCM)................................. 44
Full-Bridge PWM Output........................................... 120
Half-Bridge PWM Output .......................................... 119
I2C Bus Data............................................................. 231
I2C Bus Start/Stop Bits ............................................. 230
I2C Reception (7-bit Address)................................... 166
I2C Slave Mode (Transmission, 10-bit Address) ...... 170
I2C Slave Mode with SEN = 0 (Reception,
10-bit Address) ................................................. 168
I2C Transmission (7-bit Address) ............................. 169
INT Pin Interrupt ....................................................... 185
PWM Auto-shutdown
Auto-restart Disabled........................................ 128
Auto-restart Enabled......................................... 128
PWM Direction Change ............................................ 122
PWM Direction Change at Near 100% Duty Cycle... 122
PWM Output (Active-High) ....................................... 118
PWM Output (Active-Low) ........................................ 118
Reset, WDT, OST and Power-up Timer ................... 222
Send Break Character Sequence............................. 147
Slave Synchronization .............................................. 161
SPI Master Mode (CKE = 1, SMP = 1) ..................... 228
SPI Mode (Master Mode) ......................................... 160
SPI Mode (Slave Mode with CKE = 0)...................... 162
Preliminary
DS41262A-page 251
PIC16F685/687/689/690
SPI Mode (Slave Mode with CKE = 1) ...................... 162
SPI Slave Mode (CKE = 0) ....................................... 229
SPI Slave Mode (CKE = 1) ....................................... 229
Synchronous Reception (Master Mode, SREN) ....... 150
Synchronous Transmission....................................... 148
Synchronous Transmission (Through TXEN) ........... 149
Time-out Sequence
Case 1............................................................... 179
Case 2............................................................... 179
Case 3............................................................... 179
Timer0 and Timer1 External Clock ........................... 224
Timer1 Incrementing Edge.......................................... 74
Two Speed Start-up .................................................... 42
Wake-up from Interrupt ............................................. 190
Timing Parameter Symbology........................................... 218
Timing Requirements
I2C Bus Data ............................................................. 232
I2C Bus Start/Stop Bits ............................................. 231
SPI Mode .................................................................. 230
TRISA
Registers ..................................................................... 47
TRISA Register ................................................................... 48
TRISB
Registers ..................................................................... 56
TRISB Register ................................................................... 57
TRISC
Registers ..................................................................... 64
TRISC Register ................................................................... 64
Two-Speed Clock Start-up Mode ........................................ 41
TXREG.............................................................................. 141
TXSTA Register ................................................................ 132
BRGH Bit .................................................................. 135
W
Wake-up Using Interrupts ................................................. 189
Watchdog Timer (WDT).................................................... 187
Associated registers ................................................. 188
Specifications ........................................................... 223
WCOL bit .......................................................................... 157
WDTCON Register ........................................................... 188
WPUA Register................................................................... 48
WPUB Register................................................................... 57
Write Collision Detect bit (WCOL) .................................... 157
WWW Address ................................................................. 253
WWW, On-Line Support ....................................................... 4
U
UA ..................................................................................... 156
Ultra Low-Power Wake-up ...................................... 12, 47, 50
Ultra Low-power Wake-up............................................... 8, 10
Update Address bit, UA..................................................... 156
V
Voltage Reference (VR)
Specifications ............................................................ 226
Voltage Reference. See Comparator Voltage Reference
(CVREF)
Voltage References
VP6 Stabilization ......................................................... 89
VRCON Register................................................................. 90
VREF. SEE A/D Reference Voltage
DS41262A-page 252
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
THE MICROCHIP WEB SITE
CUSTOMER SUPPORT
Microchip provides online support via our WWW site at
www.microchip.com. This web site is used as a means
to make files and information easily available to
customers. Accessible by using your favorite Internet
browser, the web site contains the following
information:
Users of Microchip products can receive assistance
through several channels:
• Product Support – Data sheets and errata,
application notes and sample programs, design
resources, user’s guides and hardware support
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• General Technical Support – Frequently Asked
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CUSTOMER CHANGE NOTIFICATION
SERVICE
Microchip’s customer notification service helps keep
customers current on Microchip products. Subscribers
will receive e-mail notification whenever there are
changes, updates, revisions or errata related to a
specified product family or development tool of interest.
•
•
•
•
•
Distributor or Representative
Local Sales Office
Field Application Engineer (FAE)
Technical Support
Development Systems Information Line
Customers
should
contact
their
distributor,
representative or field application engineer (FAE) for
support. Local sales offices are also available to help
customers. A listing of sales offices and locations is
included in the back of this document.
Technical support is available through the web site
at: http://support.microchip.com
In addition, there is a Development Systems
Information Line which lists the latest versions of
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This line also provides information on how customers
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The Development
numbers are:
Systems
Information
Line
1-800-755-2345 – United States and most of Canada
1-480-792-7302 – Other International Locations
To register, access the Microchip web site at
www.microchip.com, click on Customer Change
Notification and follow the registration instructions.
© 2005 Microchip Technology Inc.
Preliminary
DS41262A-page 253
PIC16F685/687/689/690
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
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Device: PIC16F685/687/689/690
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Literature Number: DS41262A
Questions:
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
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7. How would you improve this document?
DS41262A-page 254
Preliminary
© 2005 Microchip Technology Inc.
PIC16F685/687/689/690
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
X
/XX
XXX
Device
Temperature
Range
Package
Pattern
Examples:
a)
b)
Device:
PIC16F685(1), PIC16F687(1), PIC16F689(1),
PIC16F690(1);
VDD range 4.2V to 5.5V
Temperature Range:
I
E
= -40°C to +85°C
= -40°C to +125°C
Package:
ML
P
SO
SS
=
=
=
=
c)
(Industrial)
(Extended)
QFN (Quad Flat, no lead)
PDIP
SOIC
SSOP
Note
Pattern:
QTP, SQTP, Code or Special Requirements
(blank otherwise)
© 2005 Microchip Technology Inc.
PIC16F685 - I/ML 301 = Industrial temp., QFN
package, QTP pattern #301.
PIC16F689 - I/SO = Industrial temp., SOIC
package.
PIC16F690T - T/E/SS = Extended temp.,
SSOP package.
Preliminary
1:
T = in tape and reel SSOP, SOIC and
QFN packages only.
DS41262A-page 255
WORLDWIDE SALES AND SERVICE
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Fax: 650-961-0286
Toronto
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Canada
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Fax: 905-673-6509
03/01/05
DS41262A-page 256
Preliminary
© 2005 Microchip Technology Inc.
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