18F8680.book Page 1 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
64/68/80-Pin High-Performance, 64-Kbyte Enhanced Flash
Microcontrollers with ECAN Module
High-Performance RISC CPU:
Analog Features:
• Source code compatible with the PIC16 and
PIC17 instruction sets
• Linear program memory addressing to 2 Mbytes
• Linear data memory addressing to 4096 bytes
• 1 Kbyte of data EEPROM
• Up to 10 MIPs operation:
- DC – 40 MHz osc./clock input
- 4 MHz-10 MHz osc./clock input with PLL active
• 16-bit wide instructions, 8-bit wide data path
• Priority levels for interrupts
• 31-level, software accessible hardware stack
• 8 x 8 Single-Cycle Hardware Multiplier
• Up to 16-channel, 10-bit Analog-to-Digital
Converter module (A/D) with:
- Fast sampling rate
- Programmable acquisition time
- Conversion available during Sleep
• Programmable 16-level Low-Voltage Detection
(LVD) module:
- Supports interrupt on Low-Voltage Detection
• Programmable Brown-out Reset (BOR)
• Dual analog comparators:
- Programmable input/output configuration
ECAN Module Features:
External Memory Interface
(PIC18F8X8X Devices Only):
• Address capability of up to 2 Mbytes
• 16-bit interface
Peripheral Features:
•
•
•
•
•
•
•
•
•
•
•
•
High current sink/source 25 mA/25 mA
Four external interrupt pins
Timer0 module: 8-bit/16-bit timer/counter
Timer1 module: 16-bit timer/counter
Timer2 module: 8-bit timer/counter
Timer3 module: 16-bit timer/counter
Secondary oscillator clock option – Timer1/Timer3
One Capture/Compare/PWM (CCP) module:
- Capture is 16-bit, max. resolution 6.25 ns
(TCY/16)
- Compare is 16-bit, max. resolution 100 ns (TCY)
- PWM output: PWM resolution is 1 to 10-bit
Enhanced Capture/Compare/PWM (ECCP) module:
- Same Capture/Compare features as CCP
- One, two or four PWM outputs
- Selectable polarity
- Programmable dead time
- Auto-shutdown on external event
- Auto-restart
Master Synchronous Serial Port (MSSP) module
with two modes of operation:
- 3-wire SPI (supports all 4 SPI modes)
- I2C™ Master and Slave mode
Enhanced Addressable USART module:
- Supports RS-232, RS-485 and LIN 1.2
- Programmable wake-up on Start bit
- Auto-baud detect
Parallel Slave Port (PSP) module
2003-2013 Microchip Technology Inc.
• Message bit rates up to 1 Mbps
• Conforms to CAN 2.0B ACTIVE Specification
• Fully backward compatible with PIC18XXX8 CAN
modules
• Three modes of operation:
- Legacy, Enhanced Legacy, FIFO
• Three dedicated transmit buffers with prioritization
• Two dedicated receive buffers
• Six programmable receive/transmit buffers
• Three full 29-bit acceptance masks
• 16 full 29-bit acceptance filters with dynamic association
• DeviceNet™ data byte filter support
• Automatic remote frame handling
• Advanced Error Management features
Special Microcontroller Features:
• 100,000 erase/write cycle Enhanced Flash
program memory typical
• 1,000,000 erase/write cycle Data EEPROM
memory typical
• 1-second programming time
• Flash/Data EEPROM Retention: > 40 years
• Self-reprogrammable under software control
• Power-on Reset (POR), Power-up Timer (PWRT)
and Oscillator Start-up Timer (OST)
• Watchdog Timer (WDT) with its own On-Chip
RC Oscillator
• Programmable code protection
• Power saving Sleep mode
• Selectable oscillator options including:
- Software enabled 4x Phase Lock Loop (of
primary oscillator)
- Secondary Oscillator (32 kHz) clock input
• In-Circuit Serial Programming™ (ICSP™) via two pins
• MPLAB® In-Circuit Debug (ICD) via two pins
DS30491D-page 1
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PIC18F6585/8585/6680/8680
CMOS Technology:
•
•
•
•
Low-power, high-speed Flash technology
Fully static design
Wide operating voltage range (2.0V to 5.5V)
Industrial and Extended temperature ranges
Program Memory
Device
Bytes
Data Memory
# Single-Word SRAM EEPROM
Instructions (bytes) (bytes)
I/O
MSSP
10-bit
A/D (ch)
CCP/
ECCP
(PWM)
SPI
ECAN/
Master AUSART
2
I C
Timers
EMA
8-bit/16-bit
PIC18F6585
48K
24576
3328
1024
53
12
1/1
Y
Y
Y/Y
2/3
N
PIC18F6680
64K
32768
3328
1024
53
12
1/1
Y
Y
Y/Y
2/3
N
PIC18F8585
48K
24576
3328
1024
69
16
1/1
Y
Y
Y/Y
2/3
Y
PIC18F8680
64K
32768
3328
1024
69
16
1/1
Y
Y
Y/Y
2/3
Y
DS30491D-page 2
2003-2013 Microchip Technology Inc.
18F8680.book Page 3 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
Pin Diagrams
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RD3/PSP3
RD2/PSP2
RD1/PSP1
VSS
VDD
RD0/PSP0
RE7/CCP2(1)
RE6/P1B
RE5/P1C
RE4
RE3
RE2/CS
64-Pin TQFP
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
RE1/WR
RE0/RD
1
48
2
47
RG0/CANTX1
RG1/CANTX2
3
4
46
45
RG2/CANRX
5
44
RB0/INT0
RB1/INT1
RB2/INT2
RB3/INT3
RB4/KBI0
RB5/KBI1/PGM
RB6/KBI2/PGC
RG3
6
43
RG5/MCLR/VPP
RG4/P1D
7
42
VSS
9
40
VSS
OSC2/CLKO/RA6
PIC18F6X8X
8
41
VDD
10
39
OSC1/CLKI
RF7/SS
RF6/AN11/C1INRF5/AN10/C1IN+/CVREF
11
38
12
37
VDD
RB7/KBI3/PGD
13
RF4/AN9/C2IN-
14
36
35
RC5/SDO
RC4/SDI/SDA
RF3/AN8/C2IN+
RF2/AN7/C1OUT
15
34
16
33
RC3/SCK/SCL
RC2/CCP1/P1A
Note 1:
RC7/RX/DT
RC6/TX/CK
RC0/T1OSO/T13CKI
RA4/T0CKI
RC1/T1OSI/CCP2(1)
RA5/AN4/LVDIN
VDD
VSS
RA0/AN0
RA1/AN1
RA2/AN2/VREF-
AVSS
RA3/AN3/VREF+
AVDD
RF0/AN5
RF1/AN6/C2OUT
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
CCP2 pin placement depends on CCP2MX setting.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
Pin Diagrams (Continued)
RE2/CS
RE3
RE4
RE5/P1C
RE6/P1B
RE7/CCP2(1)
RD0/PSP0
VDD
N/C
VSS
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
68-Pin PLCC
9 8 7 6 5 4 3 2 1 68 67 66 65 64 63 62 61
RE1/WR
RE0/RD
RG0/CANTX1
RG1/CANTX2
RG2/CANRX
RG3
RG5/MCLR/VPP
RG4/P1D
N/C
VSS
VDD
RF7/SS
RF6/AN11/C1INRF5/AN10/C1IN+/CVREF
RF4/AN9/C2INRF3/AN8/C2IN+
RF2/AN7/C1OUT
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
Top View
PIC18F6X8X
RB0/INT0
RB1/INT1
RB2/INT2
RB3/INT3
RB4/KBI0
RB5/KBI1/PGM
RB6/KBI2/PGC
VSS
N/C
OSC2/CLKO/RA6
OSC1/CLKI
VDD
RB7/KBI3/PGD
RC5/SDO
RC4/SDI/SDA
RC3/SCK/SCL
RC2/CCP1/P1A
Note 1:
VDD
RA5/AN4/LVDIN
RA4/T0CKI
RC1/T1OSI/CCP2(1)
RC0/T1OSO/T13CKI
RC6/TX/CK
RC7/RX/DT
RF1/AN6/C2OUT
RF0/AN5
AVDD
AVSS
RA3/AN3/VREF+
RA2/AN2/VREFRA1/AN1
RA0/AN0
N/C
VSS
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
CCP2 pin placement depends on CCP2MX setting.
DS30491D-page 4
2003-2013 Microchip Technology Inc.
18F8680.book Page 5 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
Pin Diagrams (Continued)
RJ1/OE
RD7/PSP7(1)/AD7
RJ0/ALE
RD6/PSP6(1)/AD6
RD5/PSP5(1)/AD5
RD4/PSP4(1)/AD4
RD3/PSP3(1)/AD3
RD2/PSP2(1)/AD2
RD1/PSP1(1)/AD1
VDD
VSS
RE7/CCP2(2)/AD15
RD0/PSP0(1)/AD0
RE6/AD14/P1B(3)
RE5/AD13/P1C(3)
RE4/AD12
RE2/CS/AD10
RE3/AD11
RH0/A16
RH1/A17
80-Pin TQFP
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61
RH2/A18
RH3/A19
1
60
2
RE1/WR/AD9
RE0/RD/AD8
3
59
58
4
57
RG0/CANTX1
RG1/CANTX2
5
6
56
55
RG2/CANRX
7
54
RG3
8
53
RG5/MCLR/VPP
RG4/P1D
9
52
PIC18F8X8X
10
VSS
11
VDD
12
51
50
RJ2/WRL
RJ3/WRH
RB0/INT0
RB1/INT1
RB2/INT2
RB3/INT3/CCP2(2)
RB4/KBI0
RB5/KBI1/PGM
RB6/KBI2/PGC
VSS
OSC2/CLKO/RA6
OSC1/CLKI
RF7/SS
13
49
48
RF6/AN11/C1IN-
14
47
RB7/KBI3/PGD
RF5/AN10/C1IN+/CVREF
15
RF4/AN9/C2IN-
16
46
45
RC5/SDO
RC4/SDI/SDA
RF3/AN8/C2IN+
RF2/AN7/C1OUT
RH7/AN15/P1B (3)
17
44
18
19
43
RC3/SCK/SCL
RC2/CCP1/P1A
20
41
RH6/AN14/P1C(3)
42
VDD
RJ7/UB
RJ6/LB
Note 1:
RJ5/CE
RJ4/BA0
RC7/RX/DT
RC6/TX/CK
RC0/T1OSO/T13CKI
RA4/T0CKI
RC1/T1OSI/CCP2(2)
VDD
RA5/AN4/LVDIN
VSS
RA0/AN0
RA1/AN1
RA2/AN2/VREF-
AVSS
RA3/AN3/VREF+
AVDD
RF0/AN5
RF1/AN6/C2OUT
RH4/AN12
RH5/AN13
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
PSP is available only in Microcontroller mode.
2:
CCP2 pin placement depends on CCP2MX and Processor mode settings.
3:
P1B and P1C pin placement depends on ECCPMX setting.
2003-2013 Microchip Technology Inc.
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18F8680.book Page 6 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 9
2.0 Oscillator Configurations ............................................................................................................................................................ 23
3.0 Reset .......................................................................................................................................................................................... 33
4.0 Memory Organization ................................................................................................................................................................. 51
5.0 Flash Program Memory .............................................................................................................................................................. 83
6.0 External Memory Interface ......................................................................................................................................................... 93
7.0 Data EEPROM Memory ........................................................................................................................................................... 101
8.0 8 x 8 Hardware Multiplier.......................................................................................................................................................... 107
9.0 Interrupts .................................................................................................................................................................................. 109
10.0 I/O Ports ................................................................................................................................................................................... 125
11.0 Timer0 Module ......................................................................................................................................................................... 155
12.0 Timer1 Module ......................................................................................................................................................................... 159
13.0 Timer2 Module ......................................................................................................................................................................... 162
14.0 Timer3 Module ......................................................................................................................................................................... 164
15.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 167
16.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................ 175
17.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 189
18.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (USART).................................................................. 229
19.0 10-bit Analog-to-Digital Converter (A/D) Module ...................................................................................................................... 249
20.0 Comparator Module.................................................................................................................................................................. 259
21.0 Comparator Voltage Reference Module ................................................................................................................................... 265
22.0 Low-Voltage Detect .................................................................................................................................................................. 269
23.0 ECAN Module........................................................................................................................................................................... 275
24.0 Special Features of the CPU .................................................................................................................................................... 345
25.0 Instruction Set Summary .......................................................................................................................................................... 365
26.0 Development Support............................................................................................................................................................... 407
27.0 Electrical Characteristics .......................................................................................................................................................... 413
28.0 DC and AC Characteristics Graphs and Tables ....................................................................................................................... 449
29.0 Packaging Information.............................................................................................................................................................. 465
Appendix A: Revision History............................................................................................................................................................. 469
Appendix B: Device Differences......................................................................................................................................................... 469
Appendix C: Conversion Considerations ........................................................................................................................................... 470
Appendix D: Migration from Mid-Range to Enhanced Devices .......................................................................................................... 470
Appendix E: Migration from High-End to Enhanced Devices............................................................................................................. 471
Index .................................................................................................................................................................................................. 473
On-Line Support................................................................................................................................................................................. 487
Systems Information and Upgrade Hot Line ...................................................................................................................................... 487
Reader Response .............................................................................................................................................................................. 488
PIC18F6585/8585/6680/8680 Product Identification System ............................................................................................................ 489
DS30491D-page 6
2003-2013 Microchip Technology Inc.
18F8680.book Page 7 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
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
E-mail at docerrors@mail.microchip.com 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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2003-2013 Microchip Technology Inc.
DS30491D-page 7
18F8680.book Page 8 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
NOTES:
DS30491D-page 8
2003-2013 Microchip Technology Inc.
18F8680.book Page 9 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
1.0
DEVICE OVERVIEW
This document contains device specific information for
the following devices:
• PIC18F6585
• PIC18F6680
• PIC18F8585
• PIC18F8680
PIC18F6X8X devices are available in 64-pin TQFP and
68-pin PLCC packages. PIC18F8X8X devices are
available in the 80-pin TQFP package. They are
differentiated from each other in four ways:
1.
2.
3.
4.
All
other
features
for
devices
in
the
PIC18F6585/8585/6680/8680 family are identical.
These are summarized in Table 1-1.
Block diagrams of the PIC18F6X8X and PIC18F8X8X
devices are provided in Figure 1-1 and Figure 1-2,
respectively. The pinouts for these device families are
listed in Table 1-2.
Flash program memory (48 Kbytes for
PIC18FX585 devices, 64 Kbytes for
PIC18FX680)
A/D channels (12 for PIC18F6X8X devices,
16 for PIC18F8X8X)
I/O ports (7 on PIC18F6X8X devices, 9 on
PIC18F8X8X)
External program memory interface (present
only on PIC18F8X8X devices)
TABLE 1-1:
PIC18F6585/8585/6680/8680 DEVICE FEATURES
Features
Operating Frequency
Program Memory (Bytes)
PIC18F6585
PIC18F6680
DC – 40 MHz
DC – 40 MHz
PIC18F8585
PIC18F8680
DC – 40 MHz
DC – 40 MHz
DC – 25 MHz w/EMA DC – 25 MHz w/EMA
48K
64K
48K (2 MB EMA)
64K (2 MB EMA)
Program Memory (Instructions)
24576
32768
24576
32768
Data Memory (Bytes)
3328
3328
3328
3328
Data EEPROM Memory (Bytes)
1024
1024
1024
1024
External Memory Interface
No
No
Yes
Yes
Interrupt Sources
29
29
29
29
Ports A-G
Ports A-G
Ports A-H, J
Ports A-H, J
I/O Ports
Timers
4
4
4
4
Capture/Compare/PWM Module
1
1
1
1
Enhanced Capture/Compare/PWM
Module
1
1
1
1
MSSP,
Enhanced AUSART,
ECAN
MSSP,
Enhanced AUSART,
ECAN
Serial Communications
MSSP,
MSSP,
Enhanced AUSART, Enhanced AUSART,
ECAN
ECAN
PSP
PSP
PSP(1)
PSP(1)
10-bit Analog-to-Digital Module
12 input channels
12 input channels
16 input channels
16 input channels
Resets (and Delays)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
Programmable Low-Voltage Detect
Yes
Yes
Yes
Yes
Programmable Brown-out Reset
Yes
Yes
Yes
Yes
75 Instructions
75 Instructions
75 Instructions
75 Instructions
64-pin TQFP,
68-pin PLCC
64-pin TQFP,
68-pin PLCC
80-pin TQFP
80-pin TQFP
Parallel Communications
Instruction Set
Package
Note 1:
PSP is only available in Microcontroller mode.
2003-2013 Microchip Technology Inc.
DS30491D-page 9
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PIC18F6585/8585/6680/8680
FIGURE 1-1:
PIC18F6X8X BLOCK DIAGRAM
Data Bus
PORTA
21
Table Pointer
8
8
Data RAM
(3328 bytes)
inc/dec logic
21
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4/LVDIN
OSC2/CLKO/RA6
Data Latch
Address Latch
21
PCLATU PCLATH
PCU PCH PCL
Program Counter
Address Latch
Program Memory
(48 Kbytes)
PORTB
12
RB2/INT2:RB0/INT0
RB3/INT3
RB4/KBI0
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
Address
4
BSR
12
4
Bank0, F
FSR0
FSR1
FSR2
31 Level Stack
12
Data Latch
PORTC
inc/dec
logic
Decode
Table Latch
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2 (1)
RC2/CCP1/P1A
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
8
16
ROM Latch
IR
PORTD
8
RD7/PSP7:RD0/PSP0
PRODH PRODL
PORTE
Instruction
Decode &
Control
8 x 8 Multiply
8
3
Power-up
Timer
OSC2/CLKO/RA6
OSC1/CLKI
Timing
Generation
W
8
BITOP
8
Oscillator
Start-up Timer
8
ALU
Power-on
Reset
PORTF
8
Watchdog
Timer
Brown-out
Reset
Test Mode
Select
Precision
Band Gap
Reference
RG5/
MCLR
8
RE0/RD
RE1/WR
RE2/CS
RE3
RE4
RE5/P1C
RE6/P1B
RE7/CCP2(1)
RF0/AN5
RF1/AN6/C2OUT
RF2/AN7/C1OUT
RF3/AN8/C2IN+
RF4/AN9/C2INRF5/AN10/C1IN+/CVREF
RF6/AN11/C1INRF7/SS
VDD, VSS
PORTG
RG0/CANTX1
RG1/CANTX2
RG2/CANRX
RG3
RG4/P1D
RG5/MCLR/VPP
BOR
LVD
Timer0
Comparator
ECCP1
Timer1
CCP2
Timer2
AUSART
Timer3
ECAN Module
Synchronous
Serial Port
10-bit
ADC
Data EEPROM
Note 1: The CCP2 pin placement depends on the CCP2MX and Processor mode settings.
DS30491D-page 10
2003-2013 Microchip Technology Inc.
18F8680.book Page 11 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
FIGURE 1-2:
PIC18F8X8X BLOCK DIAGRAM
Data Bus
AD7:AD0
PORTA
21
Table Pointer
8
8
Data RAM
(3328 bytes)
inc/dec logic
21
Address Latch
21
System Bus Interface
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4/LVDIN
OSC2/CLKO/RA6
Data Latch
PCLATU PCLATH
PCU PCH PCL
Program Counter
Address Latch
Program Memory
(64 Kbytes)
PORTB
12
RB2/INT2:RB0/INT0
RB3/INT3/CCP2 (1)
RB4/KBI0
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
Address
4
BSR
31 Level Stack
12
4
Bank0, F
FSR0
FSR1
FSR2
12
Data Latch
Decode
Table Latch
PORTC
inc/dec
logic
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1/P1A
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
8
16
ROM Latch
IR
PORTD
A16, AD15:AD8
8
RD7/PSP7/AD7:
RD0/PSP0/AD0
PRODH PRODL
PORTE
Instruction
Decode &
Control
8 x 8 Multiply
8
3
Power-up
Timer
OSC2/CLKO/RA6
OSC1/CLKI
Timing
Generation
W
8
BITOP
8
Oscillator
Start-up Timer
8
ALU
Power-on
Reset
PORTF
8
Watchdog
Timer
Brown-out
Reset
Test Mode
Select
Precision
Band Gap
Reference
RG5/
MCLR
VDD, VSS
8
RE0/RD/AD8
RE1/WR/AD9
RE2/CS/AD10
RE3/AD11
RE4/AD12
RE5/AD13/P1C(2)
RE6/AD14/P1B(2)
RE7/CCP2(1)/AD15
PORTJ
RJ0/ALE
RJ1/OE
RJ2/WRL
RJ3/WRH
RJ4/BA0
RJ5/CE
RJ6/LB
RJ7/UB
RF0/AN5
RF1/AN6/C2OUT
RF2/AN7/C1OUT
RF3/AN8/C2IN+
RF4/AN9/C2INRF5/AN10/C1IN+/CVREF
RF6/AN11/C1INRF7/SS
PORTG
RG0/CANTX1
RG1/CANTX2
RG2/CANRX
RG3
RG4/P1D
RG5/MCLR/VPP
PORTH
BOR
LVD
Comparator
Note 1:
2:
Timer0
ECCP1
Timer1
CCP2
Timer2
AUSART
RH7/AN15/P1B (2)
RH6/AN14/P1C(2)
RH5/AN13
RH4/AN12
RH3/A19:RH0/A16
Timer3
ECAN Module
Synchronous
Serial Port
10-bit
ADC
The CCP2 pin placement depends on the CCP2MX and Processor mode settings.
P1B and P1C pin placement depends on the ECCPMX setting.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
RG5/MCLR/VPP
7
16
Buffer
Type
Description
ST
ST
Master Clear (input) or programming
voltage (input).
General purpose input pin.
Master Clear (Reset) input. This pin is
an active-low Reset to the device.
Programming voltage input.
TQFP
9
I
I
RG5
MCLR
P
VPP
OSC1/CLKI
OSC1
Pin
Type
39
50
49
I
CMOS/ST
I
CMOS
O
—
CLKO
O
—
RA6
I/O
TTL
CLKI
OSC2/CLKO/RA6
OSC2
40
51
50
Oscillator crystal or external clock input.
Oscillator crystal input or external clock
source input. ST buffer when configured
in RC mode; otherwise CMOS.
External clock source input. Always
associated with pin function OSC1
(see OSC1/CLKI, OSC2/CLKO pins).
Oscillator crystal or clock output.
Oscillator crystal output.
Connects to crystal or resonator in
Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO
which has 1/4 the frequency of OSC1
and denotes the instruction cycle rate.
General purpose I/O pin.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
DS30491D-page 12
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
24
RA1/AN1
RA1
AN1
23
RA2/AN2/VREFRA2
AN2
VREF-
22
RA3/AN3/VREF+
RA3
AN3
VREF+
21
RA4/T0CKI
RA4
28
34
33
32
31
39
30
27
RA6
38
TTL
Analog
Digital I/O.
Analog input 0.
I/O
I
TTL
Analog
Digital I/O.
Analog input 1.
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 2.
A/D reference voltage (Low) input.
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 3.
A/D reference voltage (High) input.
I/O
ST/OD
I
ST
Digital I/O – Open-drain when
configured as output.
Timer0 external clock input.
I/O
I
I
TTL
Analog
Analog
29
28
27
34
T0CKI
RA5/AN4/LVDIN
RA5
AN4
LVDIN
I/O
I
33
Digital I/O.
Analog input 4.
Low-voltage detect input.
See the OSC2/CLKO/RA6 pin.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
2003-2013 Microchip Technology Inc.
DS30491D-page 13
18F8680.book Page 14 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTB is a bidirectional I/O port. PORTB
can be software programmed for internal
weak pull-ups on all inputs.
RB0/INT0
RB0
INT0
48
RB1/INT1
RB1
INT1
47
RB2/INT2
RB2
INT2
46
RB3/INT3/CCP2
RB3
INT3
CCP2(1)
45
RB4/KBI0
RB4
KBI0
44
RB5/KBI1/PGM
RB5
KBI1
PGM
43
RB6/KBI2/PGC
RB6
KBI2
PGC
42
RB7/KBI3/PGD
RB7
KBI3
PGD
37
60
59
58
57
56
55
54
48
58
I/O
I
TTL
ST
Digital I/O.
External interrupt 0.
I/O
I
TTL
ST
Digital I/O.
External interrupt 1.
I/O
I
TTL
ST
Digital I/O.
External interrupt 2.
I/O
I/O
I/O
TTL
ST
ST
Digital I/O.
External interrupt 3.
Capture 2 input/Compare 2 output/
PWM 2 output.
I/O
I
TTL
ST
Digital I/O.
Interrupt-on-change pin.
I/O
I
I/O
TTL
ST
ST
Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP Programming
enable pin.
I/O
I
I/O
TTL
ST
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP
programming clock.
I/O
I/O
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP
programming data.
57
56
55
54
53
52
47
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
DS30491D-page 14
2003-2013 Microchip Technology Inc.
18F8680.book Page 15 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTC is a bidirectional I/O port.
RC0/T1OSO/T13CKI
RC0
T1OSO
T13CKI
30
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2(1, 4)
29
RC2/CCP1/P1A
RC2
CCP1
P1A
33
RC3/SCK/SCL
RC3
SCK
34
41
40
44
45
36
35
RC5/SDO
RC5
SDO
36
RC6/TX/CK
RC6
TX
CK
31
RC7/RX/DT
RC7
RX
DT
32
46
47
42
43
ST
—
ST
Digital I/O.
Timer1 oscillator output.
Timer1/Timer3 external clock input.
I/O
I
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator input.
CCP2 Capture input/Compare output/
PWM 2 output.
I/O
I/O
I/O
ST
ST
ST
Digital I/O.
CCP1 Capture input/Compare output.
CCP1 PWM output A.
I/O
I/O
ST
ST
I/O
ST
Digital I/O.
Synchronous serial clock input/output
for SPI mode.
Synchronous serial clock input/output
for I2C mode.
I/O
I
I/O
ST
ST
ST
Digital I/O.
SPI data in.
I2C data I/O.
I/O
O
ST
—
Digital I/O.
SPI data out.
I/O
O
I/O
ST
—
ST
Digital I/O.
USART asynchronous transmit.
USART synchronous clock
(see RX/DT).
I/O
I
I/O
ST
ST
ST
Digital I/O.
USART 1 asynchronous receive.
USART 1 synchronous data
(see TX/CK).
35
43
44
SCL
RC4/SDI/SDA
RC4
SDI
SDA
I/O
O
I
45
46
37
38
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
2003-2013 Microchip Technology Inc.
DS30491D-page 15
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PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTD is a bidirectional I/O port. These
pins have TTL input buffers when external
memory is enabled.
RD0/PSP0/AD0
RD0
PSP0(6)
AD0(3)
58
RD1/PSP1/AD1
RD1
PSP1(6)
AD1(3)
55
RD2/PSP2/AD2
RD2
PSP2(6)
AD2(3)
54
RD3/PSP3/AD3
RD3
PSP3(6)
AD3(3)
53
RD4/PSP4/AD4
RD4
PSP4(6)
AD4(3)
52
RD5/PSP5/AD5
RD5
PSP5(6)
AD5(3)
51
RD6/PSP6/AD6
RD6
PSP6(6)
AD6(3)
50
RD7/PSP7/AD7
RD7
PSP7(6)
AD7(3)
49
3
67
66
65
64
63
62
61
72
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 0.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 1.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 2.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 3.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 4.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 5.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 6.
I/O
I/O
I/O
ST
TTL
TTL
Digital I/O.
Parallel Slave Port data.
External memory address/data 7.
69
68
67
66
65
64
63
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
DS30491D-page 16
2003-2013 Microchip Technology Inc.
18F8680.book Page 17 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTE is a bidirectional I/O port.
RE0/RD/AD8
RE0
RD(6)
2
11
4
AD8(3)
RE1/WR/AD9
RE1
WR(6)
1
10
64
9
63
RE4/AD12
RE4
AD12(3)
62
RE5/AD13/P1C
RE5
AD13(3)
P1C(7)
61
RE6/AD14/P1B
RE6
AD14(3)
P1B(7)
60
RE7/CCP2/AD15
RE7
CCP2(1,4)
59
AD15(3)
8
7
6
5
4
Digital I/O.
Read control for Parallel Slave Port
(see WR and CS pins).
External memory address/data 8.
I/O
TTL
I/O
I
ST
TTL
I/O
TTL
I/O
I
ST
TTL
I/O
TTL
Digital I/O.
Chip select control for Parallel Slave
Port (see RD and WR).
External memory address/data 10.
I/O
I/O
ST
TTL
Digital I/O.
External memory address/data 11.
I/O
I/O
ST
TTL
Digital I/O.
External memory address/data 12.
I/O
I/O
I/O
ST
TTL
ST
Digital I/O.
External memory address/data 13.
ECCP1 PWM output C.
I/O
I/O
I/O
ST
TTL
ST
Digital I/O.
External memory address/data 14.
ECCP1 PWM output B.
I/O
I/O
ST
ST
I/O
TTL
Digital I/O.
Capture 2 input/Compare 2 output/
PWM 2 output.
External memory address/data 15.
Digital I/O.
Write control for Parallel Slave Port
(see CS and RD pins).
External memory address/data 9.
78
AD10(3)
RE3/AD11
RE3
AD11(3)
ST
TTL
3
AD9(3)
RE2/CS/AD10
RE2
CS(6)
I/O
I
77
76
75
74
73
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
2003-2013 Microchip Technology Inc.
DS30491D-page 17
18F8680.book Page 18 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTF is a bidirectional I/O port.
RF0/AN5
RF0
AN5
18
RF1/AN6/C2OUT
RF1
AN6
C2OUT
17
RF2/AN7/C1OUT
RF2
AN7
C1OUT
16
RF3/AN8/C2IN+
RF1
AN8
C2IN+
15
RF4/AN9/C2INRF1
AN9
C2IN-
14
RF5/AN10/C1IN+/CVREF
RF1
AN10
C1IN+
CVREF
13
RF6/AN11/C1INRF6
AN11
C1IN-
12
RF7/SS
RF7
SS
11
28
27
26
25
24
23
22
21
24
I/O
I
ST
Analog
Digital I/O.
Analog input 5.
I/O
I
O
ST
Analog
ST
Digital I/O.
Analog input 6.
Comparator 2 output.
I/O
I
O
ST
Analog
ST
Digital I/O.
Analog input 7.
Comparator 1 output.
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 8.
Comparator 2 input (+).
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 9.
Comparator 2 input (-).
I/O
I
I
O
ST
Analog
Analog
Analog
Digital I/O.
Analog input 10.
Comparator 1 input (+).
Comparator VREF output.
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 11.
Comparator 1 input (-)
I/O
I
ST
TTL
Digital I/O.
SPI slave select input.
23
18
17
16
15
14
13
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
DS30491D-page 18
2003-2013 Microchip Technology Inc.
18F8680.book Page 19 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTG is a bidirectional I/O port.
RG0/CANTX1
RG0
CANTX1
3
12
RG1/CANTX2
RG1
CANTX2
4
RG2/CANRX
RG2
CANRX
5
RG3
RG3
6
15
8
RG4/P1D
RG4
P1D
8
17
10
RG5
7
13
14
16
5
I/O
O
ST
TTL
Digital I/O.
CAN bus transmit 1.
I/O
O
ST
TTL
Digital I/O.
CAN bus transmit 2.
I/O
I
ST
TTL
Digital I/O.
CAN bus receive.
I/O
ST
Digital I/O.
I/O
O
ST
TTL
Digital I/O.
ECCP1 PWM output D.
I
ST
General purpose input pin.
6
7
9
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTH is a bidirectional I/O port(5).
RH0/A16
RH0
A16
—
RH1/A17
RH1
A17
—
RH2/A18
RH2
A18
—
RH3/A19
RH3
A19
—
RH4/AN12
RH4
AN12
—
RH5/AN13
RH5
AN13
—
RH6/AN14/P1C
RH6
AN14
P1C(7)
—
RH7/AN15/P1B
RH7
AN15
P1B(7)
—
—
—
—
—
—
—
—
—
79
I/O
O
ST
TTL
Digital I/O.
External memory address 16.
I/O
O
ST
TTL
Digital I/O.
External memory address 17.
I/O
O
ST
TTL
Digital I/O.
External memory address 18.
I/O
O
ST
TTL
Digital I/O.
External memory address 19.
I/O
I
ST
Analog
Digital I/O.
Analog input 12.
I/O
I
ST
Analog
Digital I/O.
Analog input 13.
I/O
I
I/O
ST
Analog
ST
Digital I/O.
Analog input 14.
Alternate CCP1 PWM output C.
I/O
I
ST
Analog
Digital I/O.
Analog input 15.
Alternate CCP1 PWM output B.
80
1
2
22
21
20
19
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
DS30491D-page 20
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PIC18F6585/8585/6680/8680
TABLE 1-2:
PIC18F6585/8585/6680/8680 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PIC18F6X8X PIC18F8X8X
TQFP PLCC
Pin
Type
Buffer
Type
Description
TQFP
PORTJ is a bidirectional I/O port(5).
RJ0/ALE
RJ0
ALE
—
—
RJ1/OE
RJ1
OE
—
RJ2/WRL
RJ2
WRL
—
RJ3/WRH
RJ3
WRH
—
RJ4/BA0
RJ4
BA0
—
RJ5/CE
CE
—
—
40
RJ6/LB
RJ6
LB
—
—
42
RJ7/UB
RJ7
UB
—
—
—
—
—
—
62
I/O
O
ST
TTL
Digital I/O.
External memory address latch
enable.
I/O
O
ST
TTL
Digital I/O.
External memory output enable.
I/O
O
ST
TTL
Digital I/O.
External memory write low control.
I/O
O
ST
TTL
Digital I/O.
External memory write high control.
I/O
O
ST
TTL
Digital I/O.
System bus byte address 0 control.
I/O
O
ST
TTL
Digital I/O
External memory chip enable.
I/O
O
ST
TTL
Digital I/O.
External memory low byte select.
I/O
O
ST
TTL
Digital I/O.
External memory high byte select.
61
60
59
39
41
VSS
9, 25, 19, 36,
41, 56 53, 68
11, 31,
51, 70
P
—
Ground reference for logic and I/O pins.
VDD
10, 26, 2, 20,
38, 57 37, 49
12, 32,
48, 71
P
—
Positive supply for logic and I/O pins.
AVSS
20
30
26
P
—
Ground reference for analog modules.
AVDD
19
29
25
P
—
Positive supply for analog modules.
NC
—
1, 18,
35, 52
—
—
—
No connect.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST
= Schmitt Trigger input with CMOS levels
Analog = Analog input
I
= Input
O
= Output
P
= Power
OD
= Open-Drain (no P diode to VDD)
Note 1: Alternate assignment for CCP2 in all operating modes except Microcontroller – applies to PIC18F8X8X only.
2: Default assignment when CCP2MX is set.
3: External memory interface functions are only available on PIC18F8X8X devices.
4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode; otherwise, it is
multiplexed with either RB3 or RC1.
5: PORTH and PORTJ are only available on PIC18F8X8X (80-pin) devices.
6: PSP is available in Microcontroller mode only.
7: On PIC18F8X8X devices, these pins can be multiplexed with RH7/RH6 by changing the ECCPMX
configuration bit.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
NOTES:
DS30491D-page 22
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
2.0
OSCILLATOR
CONFIGURATIONS
2.1
Oscillator Types
The PIC18F6585/8585/6680/8680 devices can be
operated in eleven different oscillator modes. The user
can program four configuration bits (FOSC3, FOSC2,
FOSC1 and FOSC0) to select one of these eleven
modes:
1.
2.
3.
4.
5.
6.
LP
XT
HS
RC
EC
ECIO
Low-Power Crystal
Crystal/Resonator
High-Speed Crystal/Resonator
External Resistor/Capacitor
External Clock
External Clock with I/O
pin enabled
7. HS+PLL
High-Speed Crystal/Resonator
with PLL enabled
8. RCIO
External Resistor/Capacitor with
I/O pin enabled
9. ECIO+SPLL External Clock with software
controlled PLL
10. ECIO+PLL External Clock with PLL and I/O
pin enabled
11. HS+SPLL
High-Speed Crystal/Resonator
with software control
2.2
Crystal Oscillator/Ceramic
Resonators
In XT, LP, HS, HS+PLL or HS+SPLL Oscillator modes,
a crystal or ceramic resonator is connected to the OSC1
and OSC2 pins to establish oscillation. Figure 2-1
shows the pin connections.
The PIC18F6585/8585/6680/8680 oscillator design
requires the use of a parallel cut crystal.
Note:
Use of a series cut crystal may give a frequency out of the crystal manufacturers
specifications.
FIGURE 2-1:
C1(1)
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
CONFIGURATION)
OSC1
XTAL
To
Internal
Logic
RF(3)
Sleep
RS(2)
C2(1)
OSC2
PIC18FXX80/XX85
Note 1:
See Table 2-1 and Table 2-2 for recommended
values of C1 and C2.
2:
A series resistor (RS) may be required for AT
strip cut crystals.
3:
RF varies with the oscillator mode chosen.
TABLE 2-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Ranges Tested:
Mode
Freq
C1
C2
XT
455 kHz
2.0 MHz
4.0 MHz
68-100 pF
15-68 pF
15-68 pF
68-100 pF
15-68 pF
15-68 pF
HS
8.0 MHz
16.0 MHz
10-68 pF
10-22 pF
10-68 pF
10-22 pF
These values are for design guidance only.
See notes following this table.
Resonators Used:
2.0 MHz
Murata Erie CSA2.00MG
0.5%
4.0 MHz
Murata Erie CSA4.00MG
0.5%
8.0 MHz
Murata Erie CSA8.00MT
0.5%
16.0 MHz Murata Erie CSA16.00MX
0.5%
All resonators used did not have built-in capacitors.
Note 1: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
2: When operating below 3V VDD, or when
using certain ceramic resonators at any
voltage, it may be necessary to use high
gain HS mode, try a lower frequency
resonator, or switch to a crystal oscillator.
3: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropriate values of external components, or
verify oscillator performance.
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PIC18F6585/8585/6680/8680
TABLE 2-2:
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Ranges Tested:
Mode
Freq
C1
C2
LP
32.0 kHz
33 pF
33 pF
200 kHz
15 pF
15 pF
XT
200 kHz
47-68 pF
47-68 pF
1.0 MHz
15 pF
15 pF
4.0 MHz
15 pF
15 pF
HS
4.0 MHz
15 pF
15 pF
8.0 MHz
15-33 pF
15-33 pF
20.0 MHz
15-33 pF
15-33 pF
25.0 MHz
TBD
TBD
These values are for design guidance only.
See notes following this table.
Crystals Used
32.0 kHz
Epson C-001R32.768K-A
± 20 PPM
200 kHz
STD XTL 200.000KHz
± 20 PPM
1.0 MHz
ECS ECS-10-13-1
± 50 PPM
4.0 MHz
ECS ECS-40-20-1
± 50 PPM
8.0 MHz
Epson CA-301 8.000M-C
± 30 PPM
20.0 MHz
Epson CA-301 20.000M-C
± 30 PPM
Note 1: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
2: Rs (see Figure 2-1) may be required in
HS mode, as well as XT mode, to avoid
overdriving crystals with low drive level
specifications.
3: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropriate values of external components, or
verify oscillator performance.
An external clock source may also be connected to the
OSC1 pin in the HS, XT and LP modes, as shown in
Figure 2-2.
FIGURE 2-2:
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR
LP OSC CONFIGURATION)
OSC1
Clock from
Ext. System
PIC18FXX80/XX85
OSC2
Open
2.3
RC Oscillator
For timing insensitive applications, the “RC” and
“RCIO” device options offer additional cost savings.
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT) values and the operating temperature. In addition to this,
the oscillator frequency will vary from unit to unit, due
to normal process parameter variation. Furthermore,
the difference in lead frame capacitance between package types will also affect the oscillation frequency,
especially for low CEXT values. The user also needs to
take into account variation due to tolerance of external
R and C components used. Figure 2-3 shows how the
R/C combination is connected.
In the RC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic.
FIGURE 2-3:
RC OSCILLATOR MODE
VDD
REXT
Internal
Clock
OSC1
CEXT
PIC18FXX80/XX85
VSS
FOSC/4
Recommended values:
OSC2/CLKO
3 k REXT 100 k
CEXT > 20pF
The RCIO Oscillator mode functions like the RC mode
except that the OSC2 pin becomes an additional general purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6).
DS30491D-page 24
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PIC18F6585/8585/6680/8680
2.4
External Clock Input
2.5
The EC, ECIO, EC+PLL and EC+SPLL Oscillator
modes require an external clock source to be connected to the OSC1 pin. The feedback device between
OSC1 and OSC2 is turned off in these modes to save
current. There is a maximum 1.5 s start-up required
after a Power-on Reset, or wake-up from Sleep mode.
In the EC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic. Figure 2-4 shows the pin connections for the EC
Oscillator mode.
FIGURE 2-4:
EXTERNAL CLOCK INPUT
OPERATION
(EC CONFIGURATION)
OSC1
Clock from
Ext. System
PIC18FXX80/XX85
OSC2
FOSC/4
The ECIO Oscillator mode functions like the EC mode,
except that the OSC2 pin becomes an additional general purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6). Figure 2-5 shows the pin connections
for the ECIO Oscillator mode.
FIGURE 2-5:
EXTERNAL CLOCK INPUT
OPERATION
(ECIO CONFIGURATION)
The PLL can only be enabled when the oscillator configuration bits are programmed for High-Speed Oscillator
or External Clock mode. If they are programmed for any
other mode, the PLL is not enabled and the system clock
will come directly from OSC1. There are two types of
PLL modes: Software Controlled PLL and Configuration
bits Controlled PLL. In Software Controlled PLL mode,
PIC18F6585/8585/6680/8680 executes at regular clock
frequency after all Reset conditions. During execution,
application can enable PLL and switch to 4x clock
frequency operation by setting the PLLEN bit in the
OSCCON register. In Configuration bits Controlled PLL
mode, PIC18F6585/8585/6680/8680 always executes
with 4x clock frequency.
The type of PLL is selected by programming the
FOSC configuration bits in the CONFIG1H
Configuration register. The oscillator mode is specified
during device programming.
A PLL lock timer is used to ensure that the PLL has
locked before device execution starts. The PLL lock
timer has a time-out that is called TPLL.
OSC1
Clock from
Ext. System
PIC18FXX80/XX85
I/O (OSC2)
RA6
FIGURE 2-6:
Phase Locked Loop (PLL)
A Phase Locked Loop circuit is provided as a
programmable option for users that want to multiply the
frequency of the incoming oscillator signal by 4. For an
input clock frequency of 10 MHz, the internal clock
frequency will be multiplied to 40 MHz. This is useful for
customers who are concerned with EMI due to
high-frequency crystals.
PLL BLOCK DIAGRAM
PLL Enable
Phase
Comparator
FIN
Loop
Filter
VCO
MUX
FOUT
SYSCLK
Divide by 4
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
2.6
Oscillator Switching Feature
The PIC18F6585/8585/6680/8680 devices include a
feature that allows the system clock source to be
switched from the main oscillator to an alternate
low-frequency
clock
source.
For
the
PIC18F6585/8585/6680/8680 devices, this alternate
clock source is the Timer1 oscillator. If a low-frequency
crystal (32 kHz, for example) has been attached to the
Timer1 oscillator pins and the Timer1 oscillator has
been enabled, the device can switch to a low-power
FIGURE 2-7:
execution mode. Figure 2-7 shows a block diagram of
the system clock sources. The clock switching feature
is enabled by programming the Oscillator Switching
Enable (OSCSEN) bit in configuration register,
CONFIG1H, to a ‘0’. Clock switching is disabled in an
erased device. See Section 12.0 “Timer1 Module” for
further details of the Timer1 oscillator. See Section 24.0
“Special Features of the CPU” for configuration
register details.
DEVICE CLOCK SOURCES
PIC18FXX80/XX85
Main Oscillator
OSC2
Sleep
Tosc/4
Timer1 Oscillator
T1OSO
MUX
TOSC
OSC1
T1OSI
4 x PLL
TSCLK
TT1P
T1OSCEN
Enable
Oscillator
Clock
Source
Clock Source Option
for other Modules
DS30491D-page 26
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PIC18F6585/8585/6680/8680
2.6.1
SYSTEM CLOCK SWITCH BIT
The system clock source switching is performed under
software control. The System Clock Switch bits,
SCS1:SCS0 (OSCCON), control the clock switching. When the SCS0 bit is ‘0’, the system clock source
comes from the main oscillator that is selected by the
FOSC configuration bits in configuration register,
CONFIG1H. When the SCS0 bit is set, the system clock
source will come from the Timer1 oscillator. The SCS0
bit is cleared on all forms of Reset.
enabled (PLLEN = 1) and locked (LOCK = 1), else it will
be forced clear. When programmed with Configuration
Controlled PLL mode, the SCS1 bit will be forced clear.
Note:
When FOSC bits are programmed for software PLL
mode, the SCS1 bit can be used to select between primary oscillator/clock and PLL output. The SCS1 bit will
only have an effect on the system clock if the PLL is
REGISTER 2-1:
The Timer1 oscillator must be enabled
and operating to switch the system clock
source. The Timer1 oscillator is enabled
by setting the T1OSCEN bit in the Timer1
Control register (T1CON). If the Timer1
oscillator is not enabled, then any write to
the SCS0 bit will be ignored (SCS0 bit
forced cleared) and the main oscillator will
continue to be the system clock source.
OSCCON REGISTER
U-0
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
—
—
LOCK
PLLEN
SCS1
SCS0
bit 7
bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3
LOCK: Phase Lock Loop Lock Status bit
1 = Phase Lock Loop output is stable as system clock
0 = Phase Lock Loop output is not stable and output cannot be used as system clock
bit 2
PLLEN(1): Phase Lock Loop Enable bit
1 = Enable Phase Lock Loop output as system clock
0 = Disable Phase Lock Loop
bit 1
SCS1: System Clock Switch bit 1
When PLLEN and LOCK bits are set:
1 = Use PLL output
0 = Use primary oscillator/clock input pin
When PLLEN or LOCK bit is cleared:
Bit is forced clear.
bit 0
SCS0(2): System Clock Switch bit 0
When OSCSEN configuration bit = 0 and T1OSCEN bit = 1:
1 = Switch to Timer1 oscillator/clock pin
0 = Use primary oscillator/clock input pin
When OSCSEN and T1OSCEN are in other states:
Bit is forced clear.
Note 1: PLLEN bit is ignored when configured for ECIO+PLL and HS+PLL. This bit is used
in ECIO+SPLL and HS+SPLL modes only.
2: The setting of SCS0 = 1 supersedes SCS1 = 1.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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PIC18F6585/8585/6680/8680
2.6.2
OSCILLATOR TRANSITIONS
The sequence of events that takes place when switching from the Timer1 oscillator to the main oscillator will
depend on the mode of the main oscillator. In addition
to eight clock cycles of the main oscillator, additional
delays may take place.
PIC18F6585/8585/6680/8680 devices contain circuitry
to prevent “glitches” when switching between oscillator
sources. Essentially, the circuitry waits for eight rising
edges of the clock source that the processor is switching to. This ensures that the new clock source is stable
and that its pulse width will not be less than the shortest
pulse width of the two clock sources.
If the main oscillator is configured for an external
crystal (HS, XT, LP), then the transition will take place
after an oscillator start-up time (TOST) has occurred. A
timing diagram, indicating the transition from the
Timer1 oscillator to the main oscillator for HS, XT and
LP modes, is shown in Figure 2-9.
A timing diagram, indicating the transition from the
main oscillator to the Timer1 oscillator, is shown in
Figure 2-8. The Timer1 oscillator is assumed to be running all the time. After the SCS0 bit is set, the processor
is frozen at the next occurring Q1 cycle. After eight
synchronization cycles are counted from the Timer1
oscillator, operation resumes. No additional delays are
required after the synchronization cycles.
FIGURE 2-8:
TIMING DIAGRAM FOR TRANSITION FROM OSC1 TO TIMER1 OSCILLATOR
Q1 Q2 Q3
Q4 Q1
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
TT1P
1
T1OSI
2
3
4
5
6
7
8
TSCS
OSC1
TOSC
Internal
System
Clock
SCS
(OSCCON)
Program
Counter
Note:
TDLY
PC
PC + 2
PC + 4
TDLY is the delay from SCS high to first count of transition circuit.
FIGURE 2-9:
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS, XT, LP)
Q3
Q4
Q1
Q1
TT1P
Q2
Q3
Q4
Q1
Q2 Q3
T1OSI
OSC1
1
TOST
2
3
4
5
6
7
8
TSCS
TOSC
Internal
System Clock
SCS
(OSCCON)
Program
Counter
Note:
PC
PC + 2
PC + 6
TOST = 1024 TOSC (drawing not to scale).
DS30491D-page 28
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PIC18F6585/8585/6680/8680
If the main oscillator is configured for HS mode with
PLL active, an oscillator start-up time (TOST) plus an
additional PLL time-out (TPLL) will occur. The PLL timeout is typically 2 ms and allows the PLL to lock to the
main oscillator frequency. A timing diagram, indicating
the transition from the Timer1 oscillator to the main
oscillator for HS-PLL mode, is shown in Figure 2-10.
FIGURE 2-10:
If the main oscillator is configured for EC mode with PLL
active, only the PLL time-out (TPLL) will occur. The PLL
time-out is typically 2 ms and allows the PLL to lock to
the main oscillator frequency. A timing diagram, indicating the transition from the Timer1 oscillator to the main
oscillator for EC with PLL active, is shown in Figure 2-11.
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1
(HS WITH PLL ACTIVE, SCS1 = 1)
Q4
TT 1 P
Q1
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
T1OSI
OSC1
TOST
TPLL
TSCS
TOSC
PLL Clock
Input
1
2
3
4
5
6
7
8
Internal System
Clock
SCS
(OSCCON)
Program Counter
Note:
PC
PC + 4
PC + 2
TOST = 1024 TOSC (drawing not to scale).
FIGURE 2-11:
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1
(EC WITH PLL ACTIVE, SCS1 = 1)
Q4
TT 1 P
Q1
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
T1OSI
OSC1
TPLL
TSCS
TOSC
PLL Clock
Input
1
2
3
4
5
6
7
8
Internal System
Clock
SCS
(OSCCON)
Program Counter
PC
2003-2013 Microchip Technology Inc.
PC + 2
PC + 4
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PIC18F6585/8585/6680/8680
If the main oscillator is configured in the RC, RCIO, EC
or ECIO modes, there is no oscillator start-up time-out.
Operation will resume after eight cycles of the main
oscillator have been counted. A timing diagram, indicating the transition from the Timer1 oscillator to the
main oscillator for RC, RCIO, EC and ECIO modes, is
shown in Figure 2-12.
FIGURE 2-12:
TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)
Q3
Q4
Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
TT1P
TOSC
T1OSI
OSC1
1
2
3
4
5
6
7
8
Internal System
Clock
SCS
(OSCCON)
TSCS
Program
Counter
Note:
PC
PC + 2
PC + 4
RC Oscillator mode assumed.
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PIC18F6585/8585/6680/8680
2.7
Effects of Sleep Mode on the
On-Chip Oscillator
When the device executes a SLEEP instruction, the onchip clocks and oscillator are turned off and the device
is held at the beginning of an instruction cycle (Q1
state). With the oscillator off, the OSC1 and OSC2
signals will stop oscillating. Since all the transistor
TABLE 2-3:
switching currents have been removed, Sleep mode
achieves the lowest current consumption of the device
(only leakage currents). Enabling any on-chip feature
that will operate during Sleep will increase the current
consumed during Sleep. The user can wake from
Sleep through external Reset, Watchdog Timer Reset,
or through an interrupt.
OSC1 AND OSC2 PIN STATES IN SLEEP MODE
OSC Mode
OSC1 Pin
OSC2 Pin
RC
Floating, external resistor should pull high
At logic low
RCIO
Floating, external resistor should pull high
Configured as PORTA, bit 6
ECIO
Floating
Configured as PORTA, bit 6
EC
Floating
At logic low
Feedback inverter disabled at
quiescent voltage level
Feedback inverter disabled at
quiescent voltage level
LP, XT, and HS
Note:
2.8
See Table 3-1 in Section 3.0 “Reset”, for time-outs due to Sleep and MCLR Reset.
Power-up Delays
Power-up delays are controlled by two timers so that no
external Reset circuitry is required for most applications. The delays ensure that the device is kept in
Reset until the device power supply and clock are stable. For additional information on Reset operation, see
Section 3.0 “Reset”.
The first timer is the Power-up Timer (PWRT) which
optionally provides a fixed delay of 72 ms (nominal) on
power-up only (POR and BOR). The second timer is
the Oscillator Start-up Timer (OST), intended to keep
the chip in Reset until the crystal oscillator is stable.
2003-2013 Microchip Technology Inc.
With the PLL enabled (HS+PLL and EC+PLL Oscillator
mode), the time-out sequence following a Power-on
Reset is different from other oscillator modes. The
time-out sequence is as follows: First, the PWRT timeout is invoked after a POR time delay has expired.
Then, the Oscillator Start-up Timer (OST) is invoked.
However, this is still not a sufficient amount of time to
allow the PLL to lock at high frequencies. The PWRT
timer is used to provide an additional fixed 2 ms
(nominal) time-out to allow the PLL ample time to lock
to the incoming clock frequency.
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NOTES:
DS30491D-page 32
2003-2013 Microchip Technology Inc.
18F8680.book Page 33 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
3.0
RESET
The PIC18F6585/8585/6680/8680 devices differentiate
between various kinds of Reset:
a)
b)
c)
d)
e)
f)
g)
h)
Power-on Reset (POR)
MCLR Reset during normal operation
MCLR Reset during Sleep
Watchdog Timer (WDT) Reset (during normal
operation)
Programmable Brown-out Reset (BOR)
RESET Instruction
Stack Full Reset
Stack Underflow Reset
Most registers are not affected by a WDT wake-up
since this is viewed as the resumption of normal operation. Status bits from the RCON register, RI, TO, PD,
POR and BOR, are set or cleared differently in different
Reset situations, as indicated in Table 3-2. These bits
are used in software to determine the nature of the
Reset. See Table 3-3 for a full description of the Reset
states of all registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 3-1.
The Enhanced MCU devices have a MCLR noise filter
in the MCLR Reset path. The filter will detect and
ignore small pulses. The MCLR pin is not driven low by
any internal Resets, including the WDT.
Most registers are unaffected by a Reset. Their status
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state” on Power-on Reset, MCLR, WDT Reset, Brownout Reset, MCLR Reset during Sleep and by the
RESET instruction.
FIGURE 3-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
RESET
Instruction
Stack
Pointer
Stack Full/Underflow Reset
External Reset
MCLR
WDT
Module
SLEEP
WDT
Time-out
Reset
VDD Rise
Detect
Power-on Reset
VDD
Brown-out
Reset
S
BOREN
OST/PWRT
OST
Chip_Reset
10-bit Ripple Counter
R
Q
OSC1
PWRT
On-chip
RC OSC(1)
10-bit Ripple Counter
Enable PWRT
Enable OST(2)
Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin.
2: See Table 3-1 for time-out situations.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
3.1
Power-on Reset (POR)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected. To take advantage of the POR circuitry, tie the MCLR pin through a 1 k to 10 k resistor to VDD. This will eliminate external RC components
usually needed to create a Power-on Reset delay. A
minimum rise rate for VDD is specified (parameter
D004). For a slow rise time, see Figure 3-2.
When the device starts normal operation (i.e., exits the
Reset condition), device operating parameters (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.
FIGURE 3-2:
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW VDD POWER-UP)
R
R1
MCLR
C
PIC18FXX8X
Note 1:
External Power-on Reset circuit is required
only if the VDD power-up slope is too slow.
The diode D helps discharge the capacitor
quickly when VDD powers down.
2:
R < 40 k is recommended to make sure that
the voltage drop across R does not violate
the device’s electrical specification.
3:
R1 = 1 k to 10 k will limit any current flowing into MCLR from external capacitor C, in
the event of MCLR/VPP pin breakdown due to
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS).
3.2
Power-up Timer (PWRT)
The Power-up Timer provides a fixed nominal time-out
(parameter #33) only on power-up from the POR. The
Power-up Timer operates on an internal RC oscillator.
The chip is kept in Reset as long as the PWRT is active.
The PWRT’s time delay allows VDD to rise to an
acceptable level. A configuration bit is provided to
enable/disable the PWRT.
The power-up time delay will vary from chip-to-chip due
to VDD, temperature and process variation. See DC
parameter #33 for details.
DS30491D-page 34
Oscillator Start-up Timer (OST)
The Oscillator Start-up Timer (OST) provides 1024
oscillator cycles (from OSC1 input) delay after the
PWRT delay is over (parameter #32). This ensures that
the crystal oscillator or resonator has started and
stabilized.
The OST time-out is invoked only for XT, LP and HS
modes and only on Power-on Reset, or wake-up from
Sleep.
3.4
PLL Lock Time-out
With the PLL enabled, the time-out sequence following
a Power-on Reset is different from other oscillator
modes. A portion of the Power-up Timer is used to provide a fixed time-out that is sufficient for the PLL to lock
to the main oscillator frequency. This PLL lock time-out
(TPLL) is typically 2 ms and follows the oscillator
start-up time-out (OST).
3.5
VDD
D
3.3
Brown-out Reset (BOR)
A configuration bit, BOREN, can disable (if clear/
programmed), or enable (if set) the Brown-out Reset
circuitry. If VDD falls below parameter D005 for greater
than parameter #35, the brown-out situation will reset
the chip. A Reset may not occur if VDD falls below
parameter D005 for less than parameter #35. The chip
will remain in Brown-out Reset until VDD rises above
BVDD. If the Power-up Timer is enabled, it will be
invoked after VDD rises above BVDD; it then will keep
the chip in Reset for an additional time delay (parameter #33). If VDD drops below BVDD while the Power-up
Timer is running, the chip will go back into a Brown-out
Reset and the Power-up Timer will be initialized. Once
VDD rises above BVDD, the Power-up Timer will
execute the additional time delay.
3.6
Time-out Sequence
On power-up, the time-out sequence is as follows:
First, PWRT time-out is invoked after the POR time
delay has expired. Then, OST is activated. The total
time-out will vary based on oscillator configuration and
the status of the PWRT. For example, in RC mode with
the PWRT disabled, there will be no time-out at all.
Figure 3-3, Figure 3-4, Figure 3-5, Figure 3-6 and
Figure 3-7 depict time-out sequences on power-up.
Since the time-outs occur from the POR pulse, the
time-outs will expire if MCLR is kept low long enough.
Bringing MCLR high will begin execution immediately
(Figure 3-5). This is useful for testing purposes or to
synchronize more than one PIC18FXX8X device
operating in parallel.
Table 3-2 shows the Reset conditions for some Special
Function Registers while Table 3-3 shows the Reset
conditions for all of the registers.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 3-1:
TIME-OUT IN VARIOUS SITUATIONS
Power-up(2)
Oscillator
Configuration
HS with PLL
Brown-out
PWRTE = 0
enabled(1)
72 ms + 1024 TOSC + 2ms
HS, XT, LP
1024 TOSC + 2 ms 1024 TOSC + 2 ms
1024 TOSC + 2 ms
72 ms + 2ms
1.5 s + 2 ms
2 ms
1.5 s + 2 ms
72 ms + 1024 TOSC
1024 TOSC
1024 TOSC
1024 TOSC
72 ms
1.5 s
1.5 s
1.5 s(3)
72 ms
1.5 s
1.5 s
1.5 s
EC with PLL enabled(1)
EC
External RC
Note 1:
2:
3:
PWRTE = 1
Wake-up from
Sleep or
Oscillator Switch
2 ms is the nominal time required for the 4x PLL to lock.
72 ms is the nominal power-up timer delay if implemented.
1.5 s is the recovery time from Sleep. There is no recovery time from oscillator switch.
REGISTER 3-1:
RCON REGISTER BITS AND POSITIONS
R/W-0
U-0
U-0
R/W-1
R/W-1
R/W-1
R/W-1
R/W-0
IPEN
—
—
RI
TO
PD
POR
BOR
bit 7
Note:
TABLE 3-2:
bit 0
Refer to Section 4.14 “RCON Register” for bit definitions.
STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR
RCON REGISTER
Program
Counter
RCON
Register
RI
TO
PD
POR
BOR
STKFUL
STKUNF
Power-on Reset
0000h
0--1 1100
1
1
1
0
0
u
u
MCLR Reset during normal
operation
0000h
0--u uuuu
u
u
u
u
u
u
u
Software Reset during normal
operation
0000h
0--0 uuuu
0
u
u
u
u
u
u
Stack Full Reset during normal
operation
0000h
0--u uu11
u
u
u
u
u
u
1
Stack Underflow Reset during
normal operation
0000h
0--u uu11
u
u
u
u
u
1
u
Condition
MCLR Reset during Sleep
0000h
0--u 10uu
u
1
0
u
u
u
u
WDT Reset
0000h
0--u 01uu
1
0
1
u
u
u
u
WDT Wake-up
PC + 2
u--u 00uu
u
0
0
u
u
u
u
Brown-out Reset
0000h
0--1 11u0
1
1
1
1
0
u
u
PC + 2(1)
u--u 00uu
u
1
0
u
u
u
u
Interrupt wake-up from Sleep
Legend: u = unchanged, x = unknown, – = unimplemented bit, read as ‘0’
Note 1: When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the
interrupt vector (000008h or 000018h).
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
TOSU
PIC18F6X8X PIC18F8X8X
---0 0000
---0 0000
---0 uuuu(3)
TOSH
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu(3)
TOSL
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu(3)
STKPTR
PIC18F6X8X PIC18F8X8X
00-0 0000
uu-0 0000
uu-u uuuu(3)
PCLATU
PIC18F6X8X PIC18F8X8X
---0 0000
---0 0000
---u uuuu
PCLATH
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
PCL
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
PC + 2(2)
TBLPTRU
PIC18F6X8X PIC18F8X8X
--00 0000
--00 0000
--uu uuuu
TBLPTRH
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
TBLPTRL
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
TABLAT
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
PRODH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
PRODL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
INTCON
PIC18F6X8X PIC18F8X8X
0000 000x
0000 000x
uuuu uuuu(1)
INTCON2
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu(1)
INTCON3
PIC18F6X8X PIC18F8X8X
1100 0000
1100 0000
uuuu uuuu(1)
Register
Wake-up via WDT
or Interrupt
INDF0
PIC18F6X8X PIC18F8X8X
N/A
N/A
POSTINC0
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
N/A
POSTDEC0
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
PREINC0
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
PLUSW0
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
FSR0H
PIC18F6X8X PIC18F8X8X
---- xxxx
---- uuuu
---- uuuu
FSR0L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
WREG
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
INDF1
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
POSTINC1
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
POSTDEC1
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
PREINC1
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
PLUSW1
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 36
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18F8680.book Page 37 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
FSR1H
PIC18F6X8X PIC18F8X8X
---- xxxx
---- uuuu
---- uuuu
FSR1L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
BSR
PIC18F6X8X PIC18F8X8X
---- 0000
---- 0000
---- uuuu
INDF2
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
POSTINC2
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
POSTDEC2
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
Register
PREINC2
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
PLUSW2
PIC18F6X8X PIC18F8X8X
N/A
N/A
N/A
FSR2H
PIC18F6X8X PIC18F8X8X
---- xxxx
---- uuuu
---- uuuu
FSR2L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
STATUS
PIC18F6X8X PIC18F8X8X
---x xxxx
---u uuuu
---u uuuu
TMR0H
PIC18F6X8X PIC18F8X8X
0000 0000
uuuu uuuu
uuuu uuuu
TMR0L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
T0CON
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
OSCCON
PIC18F6X8X PIC18F8X8X
---- 0000
---- 0000
---- uuuu
LVDCON
PIC18F6X8X PIC18F8X8X
--00 0101
--00 0101
--uu uuuu
WDTCON
PIC18F6X8X PIC18F8X8X
---- ---0
---- ---0
---- ---u
RCON(4)
PIC18F6X8X PIC18F8X8X
0--q 11qq
0--q qquu
u--u qquu
TMR1H
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TMR1L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
T1CON
PIC18F6X8X PIC18F8X8X
0-00 0000
u-uu uuuu
u-uu uuuu
TMR2
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
PR2
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
1111 1111
T2CON
PIC18F6X8X PIC18F8X8X
-000 0000
-000 0000
-uuu uuuu
SSPBUF
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
SSPADD
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
SSPSTAT
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
SSPCON1
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
SSPCON2
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 37
18F8680.book Page 38 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
ADRESH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADRESL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADCON0
PIC18F6X8X PIC18F8X8X
--00 0000
--00 0000
--uu uuuu
ADCON1
PIC18F6X8X PIC18F8X8X
--00 0000
--00 0000
--uu uuuu
ADCON2
PIC18F6X8X PIC18F8X8X
0-00 0000
0-00 0000
u-uu uuuu
CCPR1H
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCPR1L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCP1CON
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
CCPR2H
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCPR2L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCP2CON
PIC18F6X8X PIC18F8X8X
--00 0000
--00 0000
--uu uuuu
CCPAS1
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
CVRCON
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
CMCON
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
TMR3H
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TMR3L
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
T3CON
PIC18F6X8X PIC18F8X8X
0000 0000
uuuu uuuu
uuuu uuuu
PSPCON
PIC18F6X8X PIC18F8X8X
0000 ----
0000 ----
uuuu ----
SPBRG
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RCREG
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
TXREG
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
TXSTA
PIC18F6X8X PIC18F8X8X
0000 0010
0000 0010
uuuu uuuu
RCSTA
PIC18F6X8X PIC18F8X8X
0000 000x
0000 000x
uuuu uuuu
EEADRH
PIC18F6X8X PIC18F8X8X
---- --00
---- --00
---- --uu
EEADR
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
EEDATA
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
EECON2
PIC18F6X8X PIC18F8X8X
xx-0 x000
uu-0 u000
uu-0 u000
EECON1
PIC18F6X8X PIC18F8X8X
00-0 x000
00-0 u000
uu-u uuuu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 38
2003-2013 Microchip Technology Inc.
18F8680.book Page 39 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
IPR3
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
PIR3
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
PIE3
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
IPR2
PIC18F6X8X PIC18F8X8X
-1-1 1111
-1-1 1111
-u-u uuuu
PIR2
PIC18F6X8X PIC18F8X8X
-0-0 0000
-0-0 0000
-u-u uuuu(1)
PIE2
PIC18F6X8X PIC18F8X8X
-0-0 0000
-0-0 0000
-u-u uuuu
IPR1
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
PIR1
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu(1)
PIE1
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
MEMCON
PIC18F6X8X PIC18F8X8X
0-00 --00
0-00 --00
u-uu --uu
TRISJ
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
TRISH
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
TRISG
PIC18F6X8X PIC18F8X8X
---1 1111
---1 1111
---u uuuu
TRISF
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
TRISE
PIC18F6X8X PIC18F8X8X
0000 -111
0000 -111
uuuu -uuu
TRISD
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
TRISC
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
TRISB
PIC18F6X8X PIC18F8X8X
1111 1111
1111 1111
uuuu uuuu
TRISA(5,6)
PIC18F6X8X PIC18F8X8X
-111 1111(5)
-111 1111(5)
-uuu uuuu(5)
Register
LATJ
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATG
PIC18F6X8X PIC18F8X8X
---x xxxx
---u uuuu
---u uuuu
LATF
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATE
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATD
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATC
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATB
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATA(5,6)
PIC18F6X8X PIC18F8X8X
-xxx xxxx(5)
-uuu uuuu(5)
-uuu uuuu(5)
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 39
18F8680.book Page 40 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
PORTJ
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTH
PIC18F6X8X PIC18F8X8X
0000 xxxx
0000 uuuu
uuuu uuuu
PORTG
PIC18F6X8X PIC18F8X8X
--xx xxxx
--uu uuuu
--uu uuuu
PORTF
PIC18F6X8X PIC18F8X8X
x000 0000
u000 0000
u000 0000
PORTE
PIC18F6X8X PIC18F8X8X
---- -000
---- -000
---- -uuu
PORTD
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTC
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTB
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTA(5,6)
PIC18F6X8X PIC18F8X8X
-x0x 0000(5)
-u0u 0000(5)
-uuu uuuu(5)
SPBRGH
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
BAUDCON
PIC18F6X8X PIC18F8X8X
-1-0 0-00
-1-0 0-00
-u-u u-uu
ECCP1DEL
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
ECANCON
PIC18F6X8X PIC18F8X8X
0001 0000
0001 0000
uuuu uuuu
TXERRCNT
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXERRCNT
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
COMSTAT
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
CIOCON
PIC18F6X8X PIC18F8X8X
0000 ----
0000 ----
uuuu ----
BRGCON3
PIC18F6X8X PIC18F8X8X
00-- -000
00-- -000
uu-- -uuu
BRGCON2
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
BRGCON1
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
CANCON
PIC18F6X8X PIC18F8X8X
1000 000-
1000 000-
uuuu uuu-
CANSTAT
PIC18F6X8X PIC18F8X8X
100- 000-
100- 000-
uuu- uuu-
RXB0D7
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D6
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D5
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D4
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D3
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D2
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D1
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0D0
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0DLC
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 40
2003-2013 Microchip Technology Inc.
18F8680.book Page 41 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
RXB0EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0SIDL
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
RXB0SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB0CON
PIC18F6X8X PIC18F8X8X
000- 0000
000- 0000
uuu- uuuu
RXB1D7
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D6
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D5
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D4
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D3
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D2
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D1
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1D0
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1DLC
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
RXB1EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1SIDL
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
RXB1SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXB1CON
PIC18F6X8X PIC18F8X8X
000- 0000
000- 0000
uuu- uuuu
TXB0D7
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D6
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D5
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D4
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D3
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D2
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D1
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0D0
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0DLC
PIC18F6X8X PIC18F8X8X
-x-- xxxx
-u-- uuuu
-u-- uuuu
TXB0EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
TXB0SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 41
18F8680.book Page 42 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
TXB0SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB0CON
PIC18F6X8X PIC18F8X8X
0000 0-00
0000 0-00
uuuu u-uu
TXB1D7
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D6
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D5
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D4
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D3
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D2
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D1
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1D0
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1DLC
PIC18F6X8X PIC18F8X8X
-x-- xxxx
-u-- uuuu
-u-- uuuu
TXB1EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB1SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- uu-u
TXB1SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
TXB1CON
PIC18F6X8X PIC18F8X8X
0000 0-00
0000 0-00
uuuu u-uu
TXB2D7
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D6
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D5
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D4
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D3
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D2
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D1
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2D0
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
0uuu uuuu
TXB2DLC
PIC18F6X8X PIC18F8X8X
-x-- xxxx
-u-- uuuu
-u-- uuuu
TXB2EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB2EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
TXB2SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
TXB2SIDH
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
TXB2CON
PIC18F6X8X PIC18F8X8X
0000 0-00
0000 0-00
uuuu u-uu
RXM1EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 42
2003-2013 Microchip Technology Inc.
18F8680.book Page 43 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
RXM1EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXM1SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXM1SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXM0EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXM0EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXM0SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXM0SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF5EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF5EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF5SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF5SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF4EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF4EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF4SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF4SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF3EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF3EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF3SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF3SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF2EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF2EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF2SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF2SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF1EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF1EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF1SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF1SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF0EIDL
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF0EIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF0SIDL
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF0SIDH
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 43
18F8680.book Page 44 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
B5D7(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D6(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D5(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D4(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D3(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D2(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D1(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5D0(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5DLC(7)
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
B5EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B5SIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B5SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B5CON(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
B4D7(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D6(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D5(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D4(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D3(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D2(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D1(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4D0(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4DLC(7)
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
B4EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4SIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B4SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B4CON(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
B3D7(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3D6(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3D5(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 44
2003-2013 Microchip Technology Inc.
18F8680.book Page 45 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
B3D4(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3D3(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3D2(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3D1(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3D0(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3DLC(7)
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
B3EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3SIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B3SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B3CON(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
B2D7(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D6(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D5(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D4(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D3(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D2(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D1(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2D0(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2DLC(7)
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
B2EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2SIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B2SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B2CON(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
B1D7(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1D6(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1D5(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1D4(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1D3(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1D2(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 45
18F8680.book Page 46 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
B1D1(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1D0(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1DLC(7)
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
B1EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1SIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B1SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B1CON(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
B0D7(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D6(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D5(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D4(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D3(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D2(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D1(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0D0(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0DLC(7)
PIC18F6X8X PIC18F8X8X
-xxx xxxx
-uuu uuuu
-uuu uuuu
B0EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0SIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx x-xx
uuuu u-uu
uuuu u-uu
B0SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
B0CON(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
TXBIE(7)
PIC18F6X8X PIC18F8X8X
---0 00--
---u uu--
---u uu--
BIE0(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
BSEL0(7)
PIC18F6X8X PIC18F8X8X
0000 00--
0000 00--
uuuu uu--
MSEL3(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
MSEL2(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
MSEL1(7)
PIC18F6X8X PIC18F8X8X
0000 0101
0000 0101
uuuu uuuu
MSEL0(7)
PIC18F6X8X PIC18F8X8X
0101 0000
0101 0000
uuuu uuuu
SDFLC(7)
PIC18F6X8X PIC18F8X8X
---0 0000
---0 0000
-u-- uuuu
RXFCON1(7)
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
Register
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 46
2003-2013 Microchip Technology Inc.
18F8680.book Page 47 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 3-3:
Register
RXFCON0(7)
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable Devices
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXFBCON7(7) PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXFBCON6(7) PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXFBCON5(7) PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXFBCON4(7) PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXFBCON3(7) PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXFBCON2(7) PIC18F6X8X PIC18F8X8X
0001 0001
0001 0001
uuuu uuuu
RXFBCON1(7) PIC18F6X8X PIC18F8X8X
0001 0001
0001 0001
uuuu uuuu
RXFBCON0(7) PIC18F6X8X PIC18F8X8X
0000 0000
0000 0000
uuuu uuuu
RXF15EIDL(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF15EIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF15SIDL(7) PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF15SIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF14EIDL(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF14EIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF14SIDL(7) PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF14SIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF13EIDL(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF13EIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF13SIDL(7) PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF13SIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF12EIDL(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF12EIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF12SIDL(7) PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF12SIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF11EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF11EIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF11SIDL(7)
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
uuu- u-uu
RXF11SIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
uuuu uuuu
RXF10EIDL(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF10EIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
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TABLE 3-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
RXF10SIDL(7) PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
-uuu uuuu
RXF10SIDH(7) PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF9EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF9EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF9SIDL(7)
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
-uuu uuuu
RXF9SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF8EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF8EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF8SIDL(7)
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
-uuu uuuu
RXF8SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF7EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF7EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF7SIDL(7)
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
-uuu uuuu
RXF7SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF6EIDL(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF6EIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
RXF6SIDL(7)
PIC18F6X8X PIC18F8X8X
xxx- x-xx
uuu- u-uu
-uuu uuuu
RXF6SIDH(7)
PIC18F6X8X PIC18F8X8X
xxxx xxxx
uuuu uuuu
-uuu uuuu
Register
Applicable Devices
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for Reset value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
oscillator modes, they are disabled and read ‘0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they read ‘0’.
7: This register reads all ‘0’s until ECAN is set up in Mode 1 or Mode 2.
DS30491D-page 48
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FIGURE 3-3:
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD VIA 1 k RESISTOR)
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 3-4:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 3-5:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
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FIGURE 3-6:
SLOW RISE TIME (MCLR TIED TO VDD VIA 1 kRESISTOR)
5V
VDD
1V
0V
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 3-7:
TIME-OUT SEQUENCE ON POR W/ PLL ENABLED
(MCLR TIED TO VDD VIA 1 kRESISTOR)
VDD
MCLR
IINTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
TPLL
OST TIME-OUT
PLL TIME-OUT
INTERNAL RESET
Note:
DS30491D-page 50
TOST = 1024 clock cycles.
TPLL 2 ms max. First three stages of the PWRT timer.
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PIC18F6585/8585/6680/8680
4.0
MEMORY ORGANIZATION
There
are
three
memory
blocks
PIC18F6585/8585/6680/8680 devices. They are:
4.1.1
in
• Program Memory
• Data RAM
• Data EEPROM
Data and program memory use separate busses which
allows for concurrent access of these blocks. Additional
detailed information for Flash program memory and data
EEPROM is provided in Section 5.0 “Flash Program
Memory” and Section 7.0 “Data EEPROM Memory”,
respectively.
In addition to on-chip Flash, the PIC18F8X8X devices
are also capable of accessing external program memory through an external memory bus. Depending on the
selected operating mode (discussed in Section 4.1.1
“PIC18F8X8X Program Memory Modes”), the
controllers may access either internal or external program memory exclusively, or both internal and external
memory in selected blocks. Additional information on
the external memory interface is provided in
Section 6.0 “External Memory Interface”.
4.1
Program Memory Organization
A 21-bit program counter is capable of addressing the
2-Mbyte program memory space. Accessing a location
between the physically implemented memory and the
2-Mbyte address will cause a read of all ‘0’s (a NOP
instruction).
The PIC18F6585 and PIC18F8585 each have
48 Kbytes of on-chip Flash memory, while the
PIC18F6680 and PIC18F8680 have 64 Kbytes of Flash.
This means that PIC18FX585 devices can store internally up to 24,576 single-word instructions and
PIC18FX680 devices can store up to 32,768 single-word
instructions.
The Reset vector address is at 0000h and the interrupt
vector addresses are at 0008h and 0018h.
Figure 4-1 shows the program memory map for
PIC18F6585/8585 devices while Figure 4-2 shows the
program memory map for PIC18F6680/8680 devices.
PIC18F8X8X PROGRAM MEMORY
MODES
PIC18F8X8X devices differ significantly from their
PIC18 predecessors in their utilization of program
memory. In addition to available on-chip Flash program
memory, these controllers can also address up to
2 Mbytes of external program memory through the
external memory interface. There are four distinct
operating modes available to the controllers:
•
•
•
•
Microprocessor (MP)
Microprocessor with Boot Block (MPBB)
Extended Microcontroller (EMC)
Microcontroller (MC)
The Program Memory mode is determined by setting
the two Least Significant bits of the CONFIG3L configuration byte, as shown in Register 4-1. (See also
Section 24.1 “Configuration Bits” for additional
details on the device configuration bits.)
The Program Memory modes operate as follows:
• The Microprocessor Mode permits access only
to external program memory; the contents of the
on-chip Flash memory are ignored. The 21-bit
program counter permits access to a 2-MByte
linear program memory space.
• The Microprocessor with Boot Block Mode
accesses on-chip Flash memory from addresses
000000h to 0007FFh. Above this, external
program memory is accessed all the way up to
the 2-MByte limit. Program execution automatically switches between the two memories as
required.
• The Microcontroller Mode accesses only
on-chip Flash memory. Attempts to read above
the physical limit of the on-chip Flash (0BFFFh for
the PIC18F8585, 0FFFFh for the PIC18F8680)
causes a read of all ‘0’s (a NOP instruction).
The Microcontroller mode is the only operating
mode available to PIC18F6X8X devices.
• The Extended Microcontroller Mode allows
access to both internal and external program
memories as a single block. The device can
access its entire on-chip Flash memory; above
this, the device accesses external program memory up to the 2-MByte program space limit. As
with Boot Block mode, execution automatically
switches between the two memories as required.
In all modes, the microcontroller has complete access
to data RAM and EEPROM.
Figure 4-3 compares the memory maps of the different
Program Memory modes. The differences between onchip and external memory access limitations are more
fully explained in Table 4-1.
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FIGURE 4-1:
INTERNAL PROGRAM
MEMORY MAP AND
STACK FOR
PIC18F6585/8585
FIGURE 4-2:
PC
21
CALL,RCALL,RETURN
RETFIE,RETLW
Stack Level 1
INTERNAL PROGRAM
MEMORY MAP AND
STACK FOR
PIC18F6680/8680
PC
21
CALL,RCALL,RETURN
RETFIE,RETLW
Stack Level 1
Stack Level 31
Stack Level 31
000000h
Reset Vector
Reset Vector
000000h
High Priority Interrupt Vector 000008h
High Priority Interrupt Vector 000008h
Low Priority Interrupt Vector 000018h
Low Priority Interrupt Vector 000018h
On-Chip Flash
Program Memory
User Memory Space
On-Chip Flash
Program Memory
Read ‘0’
00FFFFh
010000h
User Memory Space
00BFFFh
00C000h
Read ‘0’
1FFFFFh
200000h
1FFFFFh
200000h
TABLE 4-1:
MEMORY ACCESS FOR PIC18F8X8X PROGRAM MEMORY MODES
Internal Program Memory
Operating Mode
Microprocessor
External Program Memory
Execution
From
Table Read
From
Table Write To
Execution
From
Table Read
From
Table Write To
No Access
No Access
No Access
Yes
Yes
Yes
Microprocessor w/
Boot Block
Yes
Yes
Yes
Yes
Yes
Yes
Microcontroller
Yes
Yes
Yes
No Access
No Access
No Access
Extended
Microcontroller
Yes
Yes
Yes
Yes
Yes
Yes
DS30491D-page 52
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REGISTER 4-1:
CONFIG3L CONFIGURATION BYTE
R/P-1
U-0
U-0
U-0
U-0
U-0
R/P-1
R/P-1
WAIT
—
—
—
—
—
PM1
PM0
bit 7
bit 0
bit 7
WAIT: External Bus Data Wait Enable bit
1 = Wait selections unavailable, device will not wait
0 = Wait programmed by WAIT1 and WAIT0 bits of MEMCOM register (MEMCOM)
bit 6-2
Unimplemented: Read as ‘0’
bit 1-0
PM1:PM0: Processor Data Memory Mode Select bits
11 = Microcontroller mode
10 = Microprocessor mode
01 = Microcontroller with Boot Block mode
00 = Extended Microcontroller mode
Legend:
FIGURE 4-3:
R = Readable bit
P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value after erase
‘1’ = Bit is set
000000h
On-Chip
Program
Memory
(No
Program Space Execution
access)
Microprocessor
with Boot Block
Mode
000000h
0007FFh
000800h
00BFFFh(1)
00FFFFh(2)
00C000h(1)
010000h(2)
1FFFFFh
On-Chip
Flash
000000h
On-Chip
Program
Memory
1FFFFFh
External
Memory
Extended
Microcontroller
Mode
On-Chip
Flash
On-Chip
Program
Memory
00BFFFh(1)
00FFFFh(2)
00C000h(1)
010000h(2)
Reads
‘0’s
External
Program
Memory
1FFFFFh
External
Memory
Microcontroller
Mode
000000h
On-Chip
Program
Memory
External
Program
Memory
1:
2:
x = Bit is unknown
MEMORY MAPS FOR PIC18F8X8X PROGRAM MEMORY MODES
Microprocessor
Mode
Note
‘0’ = Bit is cleared
External
Program
Memory
1FFFFFh
On-Chip
Flash
External
Memory
On-Chip
Flash
PIC18F6585 and PIC18F8585.
PIC18F6680 and PIC18F8680.
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4.2
Return Address Stack
The return address stack allows any combination of up
to 31 program calls and interrupts to occur. The PC
(Program Counter) is pushed onto the stack when a
CALL or RCALL instruction is executed or an interrupt is
Acknowledged. The PC value is pulled off the stack on
a RETURN, RETLW, or a RETFIE instruction. PCLATU
and PCLATH are not affected by any of the RETURN or
CALL instructions.
The stack operates as a 31-word by 21-bit RAM and a
5-bit stack pointer, with the stack pointer initialized to
00000b after all Resets. There is no RAM associated
with stack pointer 00000b. This is only a Reset value.
During a CALL type instruction causing a push onto the
stack, the stack pointer is first incremented and the
RAM location pointed to by the stack pointer is written
with the contents of the PC. During a RETURN type
instruction causing a pop from the stack, the contents
of the RAM location pointed to by the STKPTR are
transferred to the PC and then the stack pointer is
decremented.
The stack space is not part of either program or data
space. The stack pointer is readable and writable and
the address on the top of the stack is readable and writable through SFR registers. Data can also be pushed
to or popped from the stack, using the top-of-stack
SFRs. Status bits indicate if the stack pointer is at or
beyond the 31 levels provided.
4.2.1
TOP-OF-STACK ACCESS
The top of the stack is readable and writable. Three
register locations, TOSU, TOSH and TOSL, hold the
contents of the stack location pointed to by the
STKPTR register. This allows users to implement a
software stack if necessary. After a CALL, RCALL or
interrupt, the software can read the pushed value by
reading the TOSU, TOSH and TOSL registers. These
values can be placed on a user defined software stack.
At return time, the software can replace the TOSU,
TOSH and TOSL and do a return.
4.2.2
RETURN STACK POINTER
(STKPTR)
The STKPTR register contains the stack pointer value,
the STKFUL (Stack Full) status bit, and the STKUNF
(Stack Underflow) status bits. Register 4-2 shows the
STKPTR register. The value of the stack pointer can be
0 through 31. The stack pointer increments when values
are pushed onto the stack and decrements when values
are popped off the stack. At Reset, the stack pointer
value will be ‘0’. The user may read and write the stack
pointer value. This feature can be used by a Real-Time
Operating System for return stack maintenance.
After the PC is pushed onto the stack 31 times (without
popping any values off the stack), the STKFUL bit is
set. The STKFUL bit can only be cleared in software or
by a POR.
The action that takes place when the stack becomes
full depends on the state of the STVREN (Stack
Overflow Reset Enable) configuration bit. Refer to
Section 25.0 “Instruction Set Summary” for a
description of the device configuration bits. If STVREN
is set (default), the 31st push will push the (PC + 2)
value onto the stack, set the STKFUL bit and reset the
device. The STKFUL bit will remain set and the stack
pointer will be set to ‘0’.
If STVREN is cleared, the STKFUL bit will be set on the
31st push and the stack pointer will increment to 31.
Any additional pushes will not overwrite the 31st push
and STKPTR will remain at 31.
When the stack has been popped enough times to
unload the stack, the next pop will return a value of zero
to the PC and sets the STKUNF bit while the stack
pointer remains at ‘0’. The STKUNF bit will remain set
until cleared in software or a POR occurs.
Note:
Returning a value of zero to the PC on an
underflow has the effect of vectoring the
program to the Reset vector, where the
stack conditions can be verified and
appropriate actions can be taken.
The user must disable the global interrupt enable bits
during this time to prevent inadvertent stack
operations.
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REGISTER 4-2:
STKPTR REGISTER
R/C-0
R/C-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
STKFUL(1)
STKUNF(1)
—
SP4
SP3
SP2
SP1
SP0
bit 7
bit 0
bit 7
STKFUL: Stack Full Flag bit
1 = Stack became full or overflowed
0 = Stack has not become full or overflowed
bit 6
STKUNF: Stack Underflow Flag bit
1 = Stack underflow occurred
0 = Stack underflow did not occur
bit 5
Unimplemented: Read as ‘0’
bit 4-0
SP4:SP0: Stack Pointer Location bits
Note 1: Bit 7 and bit 6 can only be cleared in user software or by a POR.
Legend:
FIGURE 4-4:
C = Clearable bit
R = Readable bit
U = Unimplemented bit, read as ‘0’ W = Writable bit
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
Return Address Stack
11111
11110
11101
TOSU
00h
TOSH
1Ah
STKPTR
00010
TOSL
34h
Top-of-Stack 001A34h
000D58h
4.2.3
PUSH AND POP INSTRUCTIONS
Since the Top-of-Stack (TOS) is readable and writable,
the ability to push values onto the stack and pull values
off the stack, without disturbing normal program execution, is a desirable option. To push the current PC value
onto the stack, a PUSH instruction can be executed.
This will increment the stack pointer and load the current PC value onto the stack. TOSU, TOSH and TOSL
can then be modified to place a return address on the
stack.
4.2.4
00011
00010
00001
00000
STACK FULL/UNDERFLOW RESETS
These Resets are enabled by programming the
STVREN configuration bit. When the STVREN bit is
disabled, a full or underflow condition will set the
appropriate STKFUL or STKUNF bit, but not cause a
device Reset. When the STVREN bit is enabled, a full
or underflow condition will set the appropriate STKFUL
or STKUNF bit and then cause a device Reset. The
STKFUL or STKUNF bits are only cleared by the user
software or a POR Reset.
The ability to pull the TOS value off of the stack and
replace it with the value that was previously pushed
onto the stack, without disturbing normal execution, is
achieved by using the POP instruction. The POP instruction discards the current TOS by decrementing the
stack pointer. The previous value pushed onto the
stack then becomes the TOS value.
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4.3
Fast Register Stack
4.4
A “fast interrupt return” option is available for interrupts.
A fast register stack is provided for the Status, WREG
and BSR registers and is only one in depth. The stack
is not readable or writable and is loaded with the
current value of the corresponding register when the
processor vectors for an interrupt. The values in the
registers are then loaded back into the working registers if the FAST RETURN instruction is used to return
from the interrupt.
A low or high priority interrupt source will push values
into the stack registers. If both low and high priority
interrupts are enabled, the stack registers cannot be
used reliably for low priority interrupts. If a high priority
interrupt occurs while servicing a low priority interrupt,
the stack register values stored by the low priority
interrupt will be overwritten.
The PC addresses bytes in the program memory. To
prevent the PC from becoming misaligned with word
instructions, the LSB of the PCL is fixed to a value of
‘0’. The PC increments by 2 to address sequential
instructions in the program memory.
If high priority interrupts are not disabled during low
priority interrupts, users must save the key registers in
software during a low priority interrupt.
The CALL, RCALL, GOTO and program branch
instructions write to the program counter directly. For
these instructions, the contents of PCLATH and
PCLATU are not transferred to the program counter.
If no interrupts are used, the fast register stack can be
used to restore the Status, WREG and BSR registers at
the end of a subroutine call. To use the fast register
stack for a subroutine call, a FAST CALL instruction
must be executed.
The contents of PCLATH and PCLATU will be transferred to the program counter by an operation that
writes PCL. Similarly, the upper two bytes of the program counter will be transferred to PCLATH and
PCLATU by an operation that reads PCL. This is useful
for computed offsets to the PC (see Section 4.8.1
“Computed GOTO”).
Example 4-1 shows a source code example that uses
the fast register stack.
EXAMPLE 4-1:
CALL SUB1, FAST
FAST REGISTER STACK
CODE EXAMPLE
4.5
;STATUS, WREG, BSR
;SAVED IN FAST REGISTER
;STACK
RETURN FAST
FIGURE 4-5:
Clocking Scheme/Instruction
Cycle
The clock input (from OSC1) is internally divided by
four to generate four non-overlapping quadrature
clocks, namely Q1, Q2, Q3 and Q4. Internally, the
program counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the instruction register in Q4. The instruction is decoded and executed during the following Q1
through Q4. The clocks and instruction execution flow
are shown in Figure 4-5.
SUB1
PCL, PCLATH and PCLATU
The program counter (PC) specifies the address of the
instruction to fetch for execution. The PC is 21 bits
wide. The low byte is called the PCL register; this register is readable and writable. The high byte is called
the PCH register. This register contains the PC
bits and is not directly readable or writable; updates to
the PCH register may be performed through the
PCLATH register. The upper byte is called PCU. This
register contains the PC bits and is not directly
readable or writable; updates to the PCU register may
be performed through the PCLATU register.
;RESTORE VALUES SAVED
;IN FAST REGISTER STACK
CLOCK/INSTRUCTION CYCLE
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
OSC1
Q1
Q2
Internal
Phase
Clock
Q3
Q4
PC
OSC2/CLKO
(RC Mode)
DS30491D-page 56
PC
Execute INST (PC-2)
Fetch INST (PC)
PC+2
Execute INST (PC)
Fetch INST (PC+2)
PC+4
Execute INST (PC+2)
Fetch INST (PC+4)
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4.6
Instruction Flow/Pipelining
A fetch cycle begins with the program counter (PC)
incrementing in Q1.
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle,
while decode and execute takes another instruction
cycle. However, due to the pipelining each instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g., GOTO),
then two cycles are required to complete the instruction
(Example 4-2).
EXAMPLE 4-2:
INSTRUCTION PIPELINE FLOW
1. MOVLW 55h
TCY0
TCY1
Fetch 1
Execute 1
Fetch 2
2. MOVWF PORTB
3. BRA
4. BSF
In the execution cycle, the fetched instruction is latched
into the “Instruction Register” (IR) in cycle Q1. This
instruction is then decoded and executed during the
Q2, Q3, and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
TCY2
TCY4
TCY5
Execute 2
Fetch 3
SUB_1
TCY3
Execute 3
Fetch 4
PORTA, 3 (Forced NOP)
Flush (NOP)
Fetch SUB_1 Execute SUB_1
5. Instruction @ address SUB_1
All instructions are single cycle except for any program branches. These take two cycles since the fetch instruction
is “flushed” from the pipeline while the new instruction is being fetched and then executed.
4.7
Instructions in Program Memory
The program memory is addressed in bytes. Instructions are stored as two bytes or four bytes in program
memory. The Least Significant Byte (LSB) of an
instruction word is always stored in a program memory
location with an even address (LSB = 0). Figure 4-6
shows an example of how instruction words are stored
in the program memory. To maintain alignment with
instruction boundaries, the PC increments in steps of 2
and the LSB will always read ‘0’ (see Section 4.4
“PCL, PCLATH and PCLATU”).
FIGURE 4-6:
The CALL and GOTO instructions have an absolute program memory address embedded into the instruction.
Since instructions are always stored on word boundaries, the data contained in the instruction is a word
address. The word address is written to PC
which accesses the desired byte address in program
memory. Instruction #2 in Figure 4-6 shows how the
instruction “GOTO 000006h” is encoded in the program
memory. Program branch instructions which encode a
relative address offset operate in the same manner.
The offset value stored in a branch instruction represents the number of single-word instructions that the
PC will be offset by. Section 25.0 “Instruction Set
Summary” provides further details of the instruction
set.
INSTRUCTIONS IN PROGRAM MEMORY
LSB = 1
LSB = 0
0Fh
0EFh
0F0h
0C1h
0F4h
55h
03h
00h
23h
56h
Program Memory
Byte Locations
Instruction 1:
Instruction 2:
MOVLW
GOTO
055h
000006h
Instruction 3:
MOVFF
123h, 456h
2003-2013 Microchip Technology Inc.
Word Address
000000h
000002h
000004h
000006h
000008h
00000Ah
00000Ch
00000Eh
000010h
000012h
000014h
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PIC18F6585/8585/6680/8680
4.7.1
TWO-WORD INSTRUCTIONS
The PIC18F6585/8585/6680/8680 devices have four
two-word instructions: MOVFF, CALL, GOTO and
LFSR. The second word of these instructions has the 4
MSBs set to ‘1’s and is a special kind of NOP instruction.
The lower 12 bits of the second word contain data to be
used by the instruction. If the first word of the instruction is executed, the data in the second word is
EXAMPLE 4-3:
accessed. If the second word of the instruction is executed by itself (first word was skipped), it will execute as
a NOP. This action is necessary when the two-word
instruction is preceded by a conditional instruction that
changes the PC. A program example that demonstrates this concept is shown in Example 4-3. Refer to
Section 25.0 “Instruction Set Summary” for further
details of the instruction set.
TWO-WORD INSTRUCTIONS
CASE 1:
Object Code
Source Code
0110 0110 0000 0000
TSTFSZ
REG1
1100 0001 0010 0011
MOVFF
REG1, REG2 ; No, execute 2-word instruction
1111 0100 0101 0110
0010 0100 0000 0000
; is RAM location 0?
; 2nd operand holds address of REG2
ADDWF
REG3
; continue code
CASE 2:
Object Code
Source Code
0110 0110 0000 0000
TSTFSZ
REG1
1100 0001 0010 0011
MOVFF
REG1, REG2 ; Yes
ADDWF
REG3
1111 0100 0101 0110
0010 0100 0000 0000
4.8
; 2nd operand becomes NOP
Look-up Tables
Look-up tables are implemented two ways. These are:
• Computed GOTO
• Table Reads
4.8.1
; is RAM location 0?
COMPUTED GOTO
A computed GOTO is accomplished by adding an offset
to the program counter (ADDWF PCL).
A look-up table can be formed with an ADDWF PCL
instruction and a group of RETLW 0xnn instructions.
WREG is loaded with an offset into the table before
executing a call to that table. The first instruction of the
called routine is the ADDWF PCL instruction. The next
instruction executed will be one of the RETLW 0xnn
instructions that returns the value 0xnn to the calling
function.
; continue code
4.8.2
TABLE READS/TABLE WRITES
A better method of storing data in program memory
allows 2 bytes of data to be stored in each instruction
location.
Look-up table data may be stored 2 bytes per program
word by using table reads and writes. The Table Pointer
(TBLPTR) specifies the byte address and the Table
Latch (TABLAT) contains the data that is read from, or
written to program memory. Data is transferred to/from
program memory, one byte at a time.
A description of the table read/table write operation is
shown in Section 5.0 “Flash Program Memory”.
The offset value (value in WREG) specifies the number
of bytes that the program counter should advance.
In this method, only one data byte may be stored in
each instruction location and room on the return
address stack is required.
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PIC18F6585/8585/6680/8680
4.9
Data Memory Organization
The data memory is implemented as static RAM. Each
register in the data memory has a 12-bit address,
allowing up to 4096 bytes of data memory. Figure 4-7
shows the data memory organization for the
PIC18F6585/8585/6680/8680 devices.
The data memory map is divided into 16 banks that
contain 256 bytes each. The lower 4 bits of the Bank
Select Register (BSR) select which bank will be
accessed. The upper 4 bits for the BSR are not
implemented.
4.9.1
GENERAL PURPOSE
REGISTER FILE
The register file can be accessed either directly or indirectly. Indirect addressing operates using a File Select
Register and corresponding Indirect File Operand. The
operation of indirect addressing is shown in
Section 4.12 “Indirect Addressing, INDF and FSR
Registers”.
Enhanced MCU devices may have banked memory in
the GPR area. GPRs are not initialized by a Power-on
Reset and are unchanged on all other Resets.
The data memory contains Special Function Registers
(SFR) and General Purpose Registers (GPR). The
SFRs are used for control and status of the controller
and peripheral functions, while GPRs are used for data
storage and scratch pad operations in the user’s application. The SFRs start at the last location of Bank 15
(0FFFh) and extend downwards. Any remaining space
beyond the SFRs in the Bank may be implemented as
GPRs. GPRs start at the first location of Bank 0 and
grow upwards. Any read of an unimplemented location
will read as ‘0’s.
Data RAM is available for use as general purpose registers by all instructions. The top section of Bank 15
(0F60h to 0FFFh) contains SFRs. All other banks of data
memory contain GPR registers, starting with Bank 0.
The entire data memory may be accessed directly or
indirectly. Direct addressing may require the use of the
BSR register. Indirect addressing requires the use of a
File Select Register (FSRn) and a corresponding Indirect File Operand (INDFn). Each FSR holds a 12-bit
address value that can be used to access any location
in the data memory map without banking.
The SFRs can be classified into two sets: those associated with the “core” function and those related to the
peripheral functions. Those registers related to the
“core” are described in this section, while those related
to the operation of the peripheral features are
described in the section of that peripheral feature. The
SFRs are typically distributed among the peripherals
whose functions they control.
The instruction set and architecture allow operations
across all banks. This may be accomplished by indirect
addressing or by the use of the MOVFF instruction. The
MOVFF instruction is a two-word/two-cycle instruction
that moves a value from one register to another.
4.9.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers (SFRs) are registers
used by the CPU and peripheral modules for controlling
the desired operation of the device. These registers are
implemented as static RAM. A list of these registers is
given in Table 4-2 and Table 4-3.
The unused SFR locations are unimplemented and
read as ‘0’s. The addresses for the SFRs are listed in
Table 4-2.
To ensure that commonly used registers (SFRs and
select GPRs) can be accessed in a single cycle regardless of the current BSR values, an Access Bank is
implemented. A segment of Bank 0 and a segment of
Bank 15 comprise the Access RAM. Section 4.10
“Access Bank” provides a detailed description of the
Access RAM.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
FIGURE 4-7:
DATA MEMORY MAP FOR PIC18FXX80/XX85 DEVICES
BSR
= 0000
= 0001
= 0010
= 0011
Data Memory Map
00h
Access RAM
FFh
00h
GPRs
Bank 0
GPRs
Bank 1
FFh
00h
Bank 2
1FFh
200h
GPRs
2FFh
300h
FFh
00h
GPRs
Bank 3
FFh
= 0100
000h
05Fh
060h
0FFh
100h
Bank 4
3FFh
400h
GPRs
Access Bank
4FFh
500h
Bank 5
to
Bank 12
= 1101
= 1110
= 1111
00h
5Fh
Access RAM high 60h
(SFRs)
FFh
Access RAM low
GPRs
CFFh
D00h
Bank 13
CAN SFRs
DFFh
E00h
00h
Bank 14
CAN SFRs
FFh
00h
CAN SFRs
FFh
SFRs
Bank 15
EFFh
F00h
F5Fh
F60h
FFFh
When a = 0,
the BSR is ignored and the
Access Bank is used.
The first 96 bytes are General
Purpose RAM (from Bank 0).
The second 160 bytes are
Special Function Registers
(from Bank 15).
When a = 1,
the BSR is used to specify the
RAM location that the instruction
uses.
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PIC18F6585/8585/6680/8680
TABLE 4-2:
SPECIAL FUNCTION REGISTER MAP
Address
Name
Address
FFFh
TOSU
FDFh
INDF2(3)
Name
Address
FBFh
CCPR1H
Name
Address
F9Fh
Name
IPR1
FFEh
TOSH
FDEh
POSTINC2(3)
FBEh
CCPR1L
F9Eh
PIR1
FFDh
TOSL
FDDh
POSTDEC2(3)
FBDh
CCP1CON
F9Dh
PIE1
FFCh
STKPTR
FDCh
PREINC2(3)
FBCh
CCPR2H
F9Ch
MEMCON(2)
FFBh
PCLATU
FDBh
PLUSW2(3)
FBBh
CCPR2L
F9Bh
—(1)
FFAh
PCLATH
FDAh
FSR2H
FBAh
CCP2CON
F9Ah
TRISJ(2)
FF9h
PCL
FD9h
FSR2L
FB9h
—(1)
F99h
TRISH(2)
F98h
TRISG
FF8h
TBLPTRU
FD8h
STATUS
FB8h
—(1)
FF7h
TBLPTRH
FD7h
TMR0H
FB7h
—(1)
F97h
TRISF
FF6h
TBLPTRL
FD6h
TMR0L
FB6h
ECCP1AS
F96h
TRISE
FF5h
TABLAT
FD5h
T0CON
FB5h
CVRCON
F95h
TRISD
FF4h
PRODH
FD4h
—(1)
FB4h
CMCON
F94h
TRISC
FF3h
PRODL
FD3h
OSCCON
FB3h
TMR3H
F93h
TRISB
FF2h
INTCON
FD2h
LVDCON
FB2h
TMR3L
F92h
TRISA
FF1h
INTCON2
FD1h
WDTCON
FB1h
T3CON
F91h
LATJ(2)
FF0h
INTCON3
FD0h
RCON
FB0h
PSPCON
F90h
LATH(2)
FEFh
INDF0(3)
FCFh
TMR1H
FAFh
SPBRG
F8Fh
LATG
FEEh
POSTINC0(3)
FCEh
TMR1L
FAEh
RCREG
F8Eh
LATF
FEDh
POSTDEC0(3)
FCDh
T1CON
FADh
TXREG
F8Dh
LATE
FECh
PREINC0(3)
FCCh
TMR2
FACh
TXSTA
F8Ch
LATD
FEBh
PLUSW0(3)
FCBh
PR2
FABh
RCSTA
F8Bh
LATC
FEAh
FSR0H
FCAh
T2CON
FAAh
EEADRH
F8Ah
LATB
FE9h
FSR0L
FC9h
SSPBUF
FA9h
EEADR
F89h
LATA
FE8h
WREG
FC8h
SSPADD
FA8h
EEDATA
F88h
PORTJ(2)
FE7h
INDF1(3)
FC7h
SSPSTAT
FA7h
EECON2
F87h
PORTH(2)
PORTG
FE6h
POSTINC1
(3)
FC6h
SSPCON1
FA6h
EECON1
F86h
FE5h
POSTDEC1(3)
FC5h
SSPCON2
FA5h
IPR3
F85h
PORTF
FE4h
PREINC1(3)
FC4h
ADRESH
FA4h
PIR3
F84h
PORTE
FE3h
PLUSW1(3)
FC3h
ADRESL
FA3h
PIE3
F83h
PORTD
FE2h
FSR1H
FC2h
ADCON0
FA2h
IPR2
F82h
PORTC
FE1h
FSR1L
FC1h
ADCON1
FA1h
PIR2
F81h
PORTB
FE0h
BSR
FC0h
ADCON2
FA0h
PIE2
F80h
PORTA
Note 1: Unimplemented registers are read as ‘0’.
2: This register is not available on PIC18F6X8X devices.
3: This is not a physical register.
2003-2013 Microchip Technology Inc.
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TABLE 4-2:
Address
SPECIAL FUNCTION REGISTER MAP (CONTINUED)
Name
F7Fh
SPBRGH
Address
Name
F5Fh
CANCON_RO0
Address
Name
F3Fh
CANCON_RO2
Address
Name
F1Fh
RXM1EIDL
RXM1EIDH
F7Eh
BAUDCON
F5Eh
CANSTAT_RO0
F3Eh
CANSTAT_RO2
F1Eh
F7Dh
—(1)
F5Dh
RXB1D7
F3Dh
TXB1D7
F1Dh
RXM1SIDL
F7Ch
—(1)
F5Ch
RXB1D6
F3Ch
TXB1D6
F1Ch
RXM1SIDH
F7Bh
—(1)
F5Bh
RXB1D5
F3Bh
TXB1D5
F1Bh
RXM0EIDL
F7Ah
—(1)
F5Ah
RXB1D4
F3Ah
TXB1D4
F1Ah
RXM0EIDH
F79h
ECCP1DEL
F59h
RXB1D3
F39h
TXB1D3
F19h
RXM0SIDL
F78h
—(1)
F58h
RXB1D2
F38h
TXB1D2
F18h
RXM0SIDH
F77h
ECANCON
F57h
RXB1D1
F37h
TXB1D1
F17h
RXF5EIDL
F76h
TXERRCNT
F56h
RXB1D0
F36h
TXB1D0
F16h
RXF5EIDH
F75h
RXERRCNT
F55h
RXB1DLC
F35h
TXB1DLC
F15h
RXF5SIDL
F74h
COMSTAT
F54h
RXB1EIDL
F34h
TXB1EIDL
F14h
RXF5SIDH
F73h
CIOCON
F53h
RXB1EIDH
F33h
TXB1EIDH
F13h
RXF4EIDL
F72h
BRGCON3
F52h
RXB1SIDL
F32h
TXB1SIDL
F12h
RXF4EIDH
F71h
BRGCON2
F51h
RXB1SIDH
F31h
TXB1SIDH
F11h
RXF4SIDL
F70h
BRGCON1
F50h
RXB1CON
F30h
TXB1CON
F10h
RXF4SIDH
F6Fh
CANCON
F4Fh
CANCON_RO1
F2Fh
CANCON_RO3
F0Fh
RXF3EIDL
F6Eh
CANSTAT
F4Eh
CANSTAT_RO1
F2Eh
CANSTAT_RO3
F0Eh
RXF3EIDH
F6Dh
RXB0D7
F4Dh
TXB0D7
F2Dh
TXB2D7
F0Dh
RXF3SIDL
F6Ch
RXB0D6
F4Ch
TXB0D6
F2Ch
TXB2D6
F0Ch
RXF3SIDH
F6Bh
RXB0D5
F4Bh
TXB0D5
F2Bh
TXB2D5
F0Bh
RXF2EIDL
F6Ah
RXB0D4
F4Ah
TXB0D4
F2Ah
TXB2D4
F0Ah
RXF2EIDH
F69h
RXB0D3
F49h
TXB0D3
F29h
TXB2D3
F09h
RXF2SIDL
F68h
RXB0D2
F48h
TXB0D2
F28h
TXB2D2
F08h
RXF2SIDH
F67h
RXB0D1
F47h
TXB0D1
F27h
TXB2D1
F07h
RXF1EIDL
F66h
RXB0D0
F46h
TXB0D0
F26h
TXB2D0
F06h
RXF1EIDH
F65h
RXB0DLC
F45h
TXB0DLC
F25h
TXB2DLC
F05h
RXF1SIDL
F64h
RXB0EIDL
F44h
TXB0EIDL
F24h
TXB2EIDL
F04h
RXF1SIDH
F63h
RXB0EIDH
F43h
TXB0EIDH
F23h
TXB2EIDH
F03h
RXF0EIDL
F62h
RXB0SIDL
F42h
TXB0SIDL
F22h
TXB2SIDL
F02h
RXF0EIDH
F61h
RXB0SIDH
F41h
TXB0SIDH
F21h
TXB2SIDH
F01h
RXF0SIDL
F60h
RXB0CON
F40h
TXB0CON
F20h
TXB2CON
F00h
RXF0SIDH
Note 1: Unimplemented registers are read as ‘0’.
2: This register is not available on PIC18F6X8X devices.
3: This is not a physical register.
DS30491D-page 62
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PIC18F6585/8585/6680/8680
TABLE 4-2:
Address
SPECIAL FUNCTION REGISTER MAP (CONTINUED)
Name
Address
Name
Address
Name
Address
Name
EFFh
—(1)
EDFh
—(1)
EBFh
—(1)
E9Fh
—(1)
EFEh
—(1)
EDEh
—(1)
EBEh
—(1)
E9Eh
—(1)
EFDh
—
(1)
EDDh
—
(1)
EBDh
—
(1)
E9Dh
—(1)
EFCh
—(1)
EDCh
—(1)
EBCh
—(1)
E9Ch
—(1)
EFBh
—
(1)
EDBh
—
(1)
EBBh
—
(1)
E9Bh
—(1)
EFAh
—
(1)
EDAh
—
(1)
EBAh
—
(1)
E9Ah
—(1)
EF9h
—(1)
ED9h
—(1)
EB9h
—(1)
E99h
—(1)
EF8h
—(1)
ED8h
—(1)
EB8h
—(1)
E98h
—(1)
EF7h
—(1)
ED7h
—(1)
EB7h
—(1)
E97h
—(1)
EF6h
—(1)
ED6h
—(1)
EB6h
—(1)
E96h
—(1)
EF5h
—
(1)
ED5h
—
(1)
EB5h
—
(1)
E95h
—(1)
EF4h
—
(1)
ED4h
—
(1)
EB4h
—
(1)
E94h
—(1)
EF3h
—(1)
ED3h
—(1)
EB3h
—(1)
E93h
—(1)
EF2h
—
(1)
ED2h
—
(1)
EB2h
—
(1)
E92h
—(1)
EF1h
—(1)
ED1h
—(1)
EB1h
—(1)
E91h
—(1)
EF0h
—(1)
ED0h
—(1)
EB0h
—(1)
E90h
—(1)
EEFh
—(1)
ECFh
—(1)
EAFh
—(1)
E8Fh
—(1)
EEEh
—
(1)
ECEh
—
(1)
EAEh
—
(1)
E8Eh
—(1)
EEDh
—(1)
ECDh
—(1)
EADh
—(1)
E8Dh
—(1)
EECh
—
(1)
ECCh
—
(1)
EACh
—
(1)
E8Ch
—(1)
EEBh
—
(1)
ECBh
—
(1)
EABh
—
(1)
E8Bh
—(1)
EEAh
—(1)
ECAh
—(1)
EAAh
—(1)
E8Ah
—(1)
EE9h
—(1)
EC9h
—(1)
EA9h
—(1)
E89h
—(1)
EE8h
—(1)
EC8h
—(1)
EA8h
—(1)
E88h
—(1)
EE7h
—(1)
EC7h
—(1)
EA7h
—(1)
E87h
—(1)
EE6h
—
(1)
EC6h
—
(1)
EA6h
—
(1)
E86h
—(1)
EE5h
—
(1)
EC5h
—
(1)
EA5h
—
(1)
E85h
—(1)
EE4h
—(1)
EC4h
—(1)
EA4h
—(1)
E84h
—(1)
EE3h
—
(1)
EC3h
—
(1)
EA3h
—
(1)
E83h
—(1)
EE2h
—
(1)
EC2h
—
(1)
EA2h
—
(1)
E82h
—(1)
EE1h
—(1)
EC1h
—(1)
EA1h
—(1)
E81h
—(1)
EE0h
—(1)
EC0h
—(1)
EA0h
—(1)
E80h
—(1)
Note 1: Unimplemented registers are read as ‘0’.
2: This register is not available on PIC18F6X8X devices.
3: This is not a physical register.
2003-2013 Microchip Technology Inc.
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TABLE 4-2:
Address
SPECIAL FUNCTION REGISTER MAP (CONTINUED)
Name
Address
Name
Address
Name
Address
Name
E7Fh CANCON_RO4
E5Fh
CANCON_RO6
E3Fh
CANCON_RO8
E1Fh
—(1)
E7Eh CANSTAT_RO4
E5Eh
CANSTAT_RO6
E3Eh
CANSTAT_RO8
E1Eh
—(1)
E7Dh
B5D7
E5Dh
B3D7
E3Dh
B1D7
E1Dh
—(1)
E7Ch
B5D6
E5Ch
B3D6
E3Ch
B1D6
E1Ch
—(1)
E7Bh
B5D5
E5Bh
B3D5
E3Bh
B1D5
E1Bh
—(1)
E7Ah
B5D4
E5Ah
B3D4
E3Ah
B1D4
E1Ah
—(1)
E79h
B5D3
E59h
B3D3
E39h
B1D3
E19h
—(1)
E78h
B5D2
E58h
B3D2
E38h
B1D2
E18h
—(1)
E77h
B5D1
E57h
B3D1
E37h
B1D1
E17h
—(1)
E76h
B5D0
E56h
B3D0
E36h
B1D0
E16h
—(1)
E75h
B5DLC
E55h
B3DLC
E35h
B1DLC
E15h
—(1)
E74h
B5EIDL
E54h
B3EIDL
E34h
B1EIDL
E14h
—(1)
E73h
B5EIDH
E53h
B3EIDH
E33h
B1EIDH
E13h
—(1)
E72h
B5SIDL
E52h
B3SIDL
E32h
B1SIDL
E12h
—(1)
E71h
B5SIDH
E51h
B3SIDH
E31h
B1SIDH
E11h
—(1)
E70h
B5CON
E50h
B3CON
E30h
B1CON
E10h
—(1)
E6Fh CANCON_RO5
E4Fh
CANCON_RO7
E2Fh
CANCON_RO9
E0Fh
—(1)
E6Eh CANSTAT_RO5
E4Eh
CANSTAT_RO7
E2Eh
CANSTAT_RO9
E0Eh
—(1)
E6Dh
B4D7
E4Dh
B2D7
E2Dh
B0D7
E0Dh
—(1)
E6Ch
B4D6
E4Ch
B2D6
E2Ch
B0D6
E0Ch
—(1)
E6Bh
B4D5
E4Bh
B2D5
E2Bh
B0D5
E0Bh
—(1)
E6Ah
B4D4
E4Ah
B2D4
E2Ah
B0D4
E0Ah
—(1)
E69h
B4D3
E49h
B2D3
E29h
B0D3
E09h
—(1)
E68h
B4D2
E48h
B2D2
E28h
B0D2
E08h
—(1)
E67h
B4D1
E47h
B2D1
E27h
B0D1
E07h
—(1)
E66h
B4D0
E46h
B2D0
E26h
B0D0
E06h
—(1)
E65h
B4DLC
E45h
B2DLC
E25h
B0DLC
E05h
—(1)
E64h
B4EIDL
E44h
B2EIDL
E24h
B0EIDL
E04h
—(1)
E63h
B4EIDH
E43h
B2EIDH
E23h
B0EIDH
E03h
—(1)
E62h
B4SIDL
E42h
B2SIDL
E22h
B0SIDL
E02h
—(1)
E61h
B4SIDH
E41h
B2SIDH
E21h
B0SIDH
E01h
—(1)
E60h
B4CON
E40h
B2CON
E20h
B0CON
E00h
—(1)
Note 1: Unimplemented registers are read as ‘0’.
2: This register is not available on PIC18F6X8X devices.
3: This is not a physical register.
DS30491D-page 64
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 4-2:
Address
SPECIAL FUNCTION REGISTER MAP (CONTINUED)
Name
Address
Name
Address
Name
Address
Name
DFFh
—(1)
DDFh
—(1)
DBFh
—(1)
D9Fh
—(1)
DFEh
—(1)
DDEh
—(1)
DBEh
—(1)
D9Eh
—(1)
DFDh
—(1)
DDDh
—(1)
DBDh
—(1)
D9Dh
—(1)
DDCh
—(1)
DBCh
—(1)
D9Ch
—(1)
DDBh
—
(1)
DBBh
—
(1)
D9Bh
—(1)
(1)
(1)
DFCh
DFBh
TXBIE
—
(1)
DFAh
BIE0
DDAh
—
DBAh
—
D9Ah
—(1)
DF9h
—(1)
DD9h
—(1)
DB9h
—(1)
D99h
—(1)
DF8h
BSEL0
DD8h
SDFLC
DB8h
—(1)
D98h
—(1)
DF7h
—(1)
DD7h
—(1)
DB7h
—(1)
D97h
—(1)
DF6h
—(1)
DD6h
—(1)
DB6h
—(1)
D96h
—(1)
DF5h
—
(1)
DB5h
—
(1)
D95h
—(1)
—
(1)
(1)
D94h
—(1)
DF4h
DD5h
RXFCON1
DD4h
RXFCON0
DB4h
—
DF3h
MSEL3
DD3h
—(1)
DB3h
—(1)
D93h
RXF15EIDL
DF2h
MSEL2
DD2h
—(1)
DB2h
—(1)
D92h
RXF15EIDH
DF1h
MSEL1
DD1h
—(1)
DB1h
—(1)
D91h
RXF15SIDL
DF0h
MSEL0
DD0h
—(1)
DB0h
—(1)
D90h
RXF15SIDH
DEFh
—(1)
DCFh
—(1)
DAFh
—(1)
D8Fh
—(1)
DEEh
—
(1)
DCEh
—
(1)
DAEh
—
(1)
D8Eh
—(1)
DEDh
—(1)
DCDh
—(1)
DADh
—(1)
D8Dh
—(1)
DECh
—
(1)
DCCh
—
(1)
DACh
—
(1)
D8Ch
—(1)
DEBh
—
(1)
DCBh
—
(1)
DABh
—
(1)
D8Bh
RXF14EIDL
DEAh
—(1)
DCAh
—(1)
DAAh
—(1)
D8Ah
RXF14EIDH
DE9h
—(1)
DC9h
—(1)
DA9h
—(1)
D89h
RXF14SIDL
DE8h
—(1)
DC8h
—(1)
DA8h
—(1)
D88h
RXF14SIDH
DE7h
RXFBCON7
DC7h
—(1)
DA7h
—(1)
D87h
RXF13EIDL
(1)
DA6h
—(1)
D86h
RXF13EIDH
DE6h
RXFBCON6
DC6h
—
DE5h
RXFBCON5
DC5h
—(1)
DA5h
—(1)
D85h
RXF13SIDL
DA4h
—(1)
D84h
RXF13SIDH
DE4h
RXFBCON4
DC4h
—(1)
DE3h
RXFBCON3
DC3h
—(1)
DA3h
—(1)
D83h
RXF12EIDL
(1)
DA2h
—(1)
D82h
RXF12EIDH
DE2h
RXFBCON2
DC2h
—
DE1h
RXFBCON1
DC1h
—(1)
DA1h
—(1)
D81h
RXF12SIDL
DE0h
RXFBCON0
DC0h
—(1)
DA0h
—(1)
D80h
RXF12SIDH
Note 1: Unimplemented registers are read as ‘0’.
2: This register is not available on PIC18F6X8X devices.
3: This is not a physical register.
2003-2013 Microchip Technology Inc.
DS30491D-page 65
18F8680.book Page 66 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-2:
Address
SPECIAL FUNCTION REGISTER MAP (CONTINUED)
Name
D7Fh
—(1)
D7Eh
—(1)
D7Dh
—(1)
D7Ch
—(1)
D7Bh
RXF11EIDL
D7Ah
RXF11EIDH
D79h
RXF11SIDL
D78h
RXF11SIDH
D77h
RXF10EIDL
D76h
RXF10EIDH
D75h
RXF10SIDL
D74h
RXF10SIDH
D73h
RXF9EIDL
D72h
RXF9EIDH
D71h
RXF9SIDL
D70h
RXF9SIDH
D6Fh
—(1)
D6Eh
—(1)
D6Dh
—(1)
D6Ch
—(1)
D6Bh
RXF8EIDL
D6Ah
RXF8EIDH
D69h
RXF8SIDL
D68h
RXF8SIDH
D67h
RXF7EIDL
D66h
RXF7EIDH
D65h
RXF7SIDL
D64h
RXF7SIDH
D63h
RXF6EIDL
D62h
RXF6EIDH
D61h
RXF6SIDL
D60h
RXF6SIDH
Address
Name
Address
Name
Address
Name
Note 1: Unimplemented registers are read as ‘0’.
2: This register is not available on PIC18F6X8X devices.
3: This is not a physical register.
DS30491D-page 66
2003-2013 Microchip Technology Inc.
18F8680.book Page 67 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
TOSU
REGISTER FILE SUMMARY
Bit 7
Bit 6
Bit 5
—
—
—
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
---0 0000
36, 54
TOSH
Top-of-Stack High Byte (TOS)
0000 0000
36, 54
TOSL
Top-of-Stack Low Byte (TOS)
0000 0000
36, 54
Return Stack Pointer
00-0 0000
36, 55
Holding Register for PC
--00 0000
36, 56
STKPTR
STKFUL
STKUNF
—
PCLATU
—
—
bit 21
Top-of-Stack Upper Byte (TOS)
Value on
Details
POR, BOR on page:
PCLATH
Holding Register for PC
0000 0000
36, 56
PCL
PC Low Byte (PC)
0000 0000
36, 56
--00 0000
36, 86
TBLPTRU
—
—
bit 21(2)
Program Memory Table Pointer Upper Byte (TBLPTR)
TBLPTRH
Program Memory Table Pointer High Byte (TBLPTR)
0000 0000
36, 86
TBLPTRL
Program Memory Table Pointer Low Byte (TBLPTR)
0000 0000
36, 86
TABLAT
Program Memory Table Latch
0000 0000
36, 86
PRODH
Product Register High Byte
xxxx xxxx 36, 107
PRODL
Product Register Low Byte
xxxx xxxx 36, 107
36, 111
INTCON
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
INTCON2
RBPU
INTEDG0
INTEDG1
INTEDG2
INTEDG3
TMR0IP
INT3IP
RBIP
1111 1111 36, 112
INT2IP
INT1IP
INT3IE
INT2IE
INT1IE
INT3IF
INT2IF
INT1IF
1100 0000 36, 113
INTCON3
INDF0
Uses contents of FSR0 to address data memory – value of FSR0 not changed (not a physical register)
n/a
79
POSTINC0
Uses contents of FSR0 to address data memory – value of FSR0 post-incremented (not a physical register)
n/a
79
POSTDEC0
Uses contents of FSR0 to address data memory – value of FSR0 post-decremented (not a physical register)
n/a
79
PREINC0
Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register)
n/a
79
PLUSW0
Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented
(not a physical register) – value of FSR0 offset by value in WREG
n/a
79
---- 0000
36, 79
FSR0L
Indirect Data Memory Address Pointer 0 Low Byte
—
xxxx xxxx
36, 79
WREG
Working Register
xxxx xxxx
36
INDF1
Uses contents of FSR1 to address data memory – value of FSR1 not changed (not a physical register)
n/a
79
POSTINC1
Uses contents of FSR1 to address data memory – value of FSR1 post-incremented (not a physical register)
n/a
79
POSTDEC1
Uses contents of FSR1 to address data memory – value of FSR1 post-decremented (not a physical register)
n/a
79
PREINC1
Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register)
n/a
79
PLUSW1
Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented
(not a physical register) – value of FSR1 offset by value in WREG
n/a
79
---- 0000
37, 79
xxxx xxxx
37, 79
---- 0000
37, 78
FSR0H
—
FSR1H
FSR1L
—
—
—
—
—
—
Indirect Data Memory Address Pointer 0 High Byte
Indirect Data Memory Address Pointer 1 High Byte
Indirect Data Memory Address Pointer 1 Low Byte
—
BSR
—
—
—
Bank Select Register
INDF2
Uses contents of FSR2 to address data memory – value of FSR2 not changed (not a physical register)
n/a
79
POSTINC2
Uses contents of FSR2 to address data memory – value of FSR2 post-incremented (not a physical register)
n/a
79
POSTDEC2
Uses contents of FSR2 to address data memory – value of FSR2 post-decremented (not a physical register)
n/a
79
PREINC2
Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register)
n/a
79
PLUSW2
Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented
(not a physical register) – value of FSR2 offset by value in WREG
n/a
79
---- 0000
37, 79
xxxx xxxx
37, 79
—
FSR2H
FSR2L
—
—
—
Indirect Data Memory Address Pointer 2 Low Byte
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
Indirect Data Memory Address Pointer 2 High Byte
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 67
18F8680.book Page 68 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
STATUS
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
—
—
—
N
OV
Z
DC
C
TMR0H
Timer0 Register High Byte
TMR0L
Timer0 Register Low Byte
T0CON
Value on
Details
POR, BOR on page:
---x xxxx
37, 81
0000 0000 37, 157
xxxx xxxx 37, 157
1111 1111 37, 155
TMR0ON
T08BIT
T0CS
T0SE
PSA
T0PS2
T0PS1
T0PS0
OSCCON
—
—
—
—
LOCK
PLLEN
SCS1
SCS
LVDCON
—
—
IRVST
LVDEN
LVDL3
LVDL2
LVDL1
LVDL0
--00 0101 37, 271
—
—
—
—
—
—
—
SWDTE
---- ---0 37, 355
IPEN
—
—
RI
TO
PD
POR
BOR
WDTCON
RCON
TMR1H
Timer1 Register High Byte
TMR1L
Timer1 Register Low Byte
T1CON
RD16
37, 82,
123
xxxx xxxx 37, 159
T1CKPS1
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON
0-00 0000 37, 159
0000 0000 37, 162
Timer2 Register
PR2
Timer2 Period Register
—
0--1 11qq
27, 37
xxxx xxxx 37, 159
—
TMR2
T2CON
---- 0000
T2OUTPS3
1111 1111 37, 163
T2OUTPS2 T2OUTPS1 T2OUTPS0
TMR2ON
T2CKPS1
T2CKPS0 -000 0000 37, 162
xxxx xxxx 37, 189
SSPBUF
SSP Receive Buffer/Transmit Register
SSPADD
SSP Address Register in I2C Slave mode. SSP Baud Rate Reload Register in I2C Master mode.
0000 0000 37, 198
SSPSTAT
SMP
CKE
D/A
P
S
R/W
UA
BF
0000 0000 37, 199
SSPCON1
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
0000 0000 37, 191
SSPCON2
GCEN
ACKSTAT
ACKDT
ACKEN
RCEN
PEN
RSEN
SEN
0000 0000 37, 201
ADRESH
A/D Result Register High Byte
ADRESL
A/D Result Register Low Byte
xxxx xxxx 38, 257
xxxx xxxx 38, 257
ADCON0
—
—
CHS3
CHS2
CHS1
CHS0
GO/DONE
ADON
--00 0000 38, 249
ADCON1
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
--00 0000 38, 257
ADCON2
ADFM
—
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
0-00 0000 38, 251
CCPR1H
Enhanced Capture/Compare/PWM Register 1 High Byte
CCPR1L
Enhanced Capture/Compare/PWM Register 1 Low Byte
CCP1CON
P1M1
P1M0
DC1B1
DC1B0
CCPR2H
Capture/Compare/PWM Register 2 High Byte
CCPR2L
Capture/Compare/PWM Register 2 Low Byte
xxxx xxxx 38, 173
xxxx xxxx 38, 172
CCP1M3
CCP1M2
CCP1M1
CCP1M0
0000 0000 38, 172
xxxx xxxx 38, 172
xxxx xxxx 38, 172
CCP2CON
—
—
DC2B1
DC2B0
CCP2M3
CCP2M2
CCP2M1
CCP2M0
ECCP1AS
ECCPASE
ECCPAS2
ECCPAS1
ECCPAS0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
CVRCON
CVREN
CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
0000 0000
CMCON
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
0000 0000 38, 259
TMR3H
Timer3 Register High Byte
TMR3L
Timer3 Register Low Byte
T3CON
PSPCON
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
--00 0000 38, 172
0000 0000 38, 172
38, 265
xxxx xxxx 38, 164
xxxx xxxx 38, 164
RD16
T3CCP2
T3CKPS1
T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
0000 0000 38, 164
IBF
OBF
IBOV
PSPMODE
—
—
—
—
0000 ---- 38, 153
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
DS30491D-page 68
2003-2013 Microchip Technology Inc.
18F8680.book Page 69 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
SPBRG
USART Baud Rate Generator
0000 0000 38, 239
RCREG
USART Receive Register
0000 0000 38, 241
TXREG
USART Transmit Register
0000 0000 38, 239
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010 38, 230
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x 38, 231
—
—
—
—
—
—
EEADRH
EE Adr Register High
---- --00 38, 105
EEADR
Data EEPROM Address Register
0000 0000 38, 105
EEDATA
Data EEPROM Data Register
0000 0000 38, 105
EECON2
Data EEPROM Control Register 2 (not a physical register)
---- ---- 38, 105
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
IPR3
IRXIP
WAKIP
ERRIP
TXB2IP/
TXBnIP
TXB1IP
TXB0IP
RXB1IP/
RXBnIP
RXB0IP/ 1111 1111 39, 122
FIFOWMIP
PIR3
IRXIF
WAKIF
ERRIF
TXB2IF/
TXBnIF
TXB1IF
TXB0IF
RXB1IF/
RXBnIF
RXB0IF/ 0000 0000 39, 116
FIFOWMIF
PIE3
IRXIE
WAKIE
ERRIE
TXB2IE/
TXBnIE
TXB1IE
TXB0IE
RXB1IE/
RXBnIE
RXB0IE/ 0000 0000 39, 119
FIFOWMIE
EECON1
RD
00-0 x000 38, 102
IPR2
—
CMIP
—
EEIP
BCLIP
LVDIP
TMR3IP
CCP2IP
-1-1 1111 39, 121
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
CCP2IF
-0-0 0000 39, 115
PIE2
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE
CCP2IE
-0-0 0000 39, 118
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
0111 1111 39, 120
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000 39, 114
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000 39, 117
MEMCON(3)
EBDIS
—
WAIT1
WAIT0
—
—
WM1
WM0
TRISJ(3)
Data Direction Control Register for PORTJ
TRISH(3)
Data Direction Control Register for PORTH
—
TRISG
—
—
0-00 --00
39, 94
1111 1111 39, 151
1111 1111 39, 148
Data Direction Control Register for PORTG
---1 1111 39, 145
TRISF
Data Direction Control Register for PORTF
1111 1111 39, 141
TRISE
Data Direction Control Register for PORTE
1111 1111 39, 138
TRISD
Data Direction Control Register for PORTD
1111 1111 39, 135
TRISC
Data Direction Control Register for PORTC
1111 1111 39, 131
TRISB
Data Direction Control Register for PORTB
1111 1111 39, 128
TRISA6(1)
-111 1111 39, 125
—
TRISA
Data Direction Control Register for PORTA
LATJ(3)
Read PORTJ Data Latch, Write PORTJ Data Latch
xxxx xxxx 39, 151
LATH(3)
Read PORTH Data Latch, Write PORTH Data Latch
xxxx xxxx 39, 148
—
LATG
—
—
Read PORTG Data Latch, Write PORTG Data Latch
---x xxxx 39, 145
LATF
Read PORTF Data Latch, Write PORTF Data Latch
xxxx xxxx 39, 141
LATE
Read PORTE Data Latch, Write PORTE Data Latch
xxxx xxxx 39, 138
LATD
Read PORTD Data Latch, Write PORTD Data Latch
xxxx xxxx 39, 133
LATC
Read PORTC Data Latch, Write PORTC Data Latch
xxxx xxxx 39, 131
LATB
Read PORTB Data Latch, Write PORTB Data Latch
xxxx xxxx 39, 128
—
LATA
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
LATA6(1)
Read PORTA Data Latch, Write PORTA Data Latch(1)
-xxx xxxx 39, 125
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 69
18F8680.book Page 70 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
PORTJ(3)
Read PORTJ pins, Write PORTJ Data Latch
xxxx xxxx 40, 151
PORTH(3)
Read PORTH pins, Write PORTH Data Latch
xxxx xxxx 40, 148
PORTG
—
—
RG5(6)
Read PORTG pins, Write PORTG Data Latch
--0x xxxx 40, 145
PORTF
Read PORTF pins, Write PORTF Data Latch
xxxx xxxx 40, 141
PORTE
Read PORTE pins, Write PORTE Data Latch
xxxx xxxx 40, 136
PORTD
Read PORTD pins, Write PORTD Data Latch
xxxx xxxx 40, 133
PORTC
Read PORTC pins, Write PORTC Data Latch
xxxx xxxx 40, 131
PORTB
Read PORTB pins, Write PORTB Data Latch
xxxx xxxx 40, 128
—
PORTA
SPBRGH
RA6(1)
Read PORTA pins, Write PORTA Data Latch(1)
-x0x 0000 40, 125
0000 0000 40, 233
Enhanced USART Baud Rate Generator High Byte
BAUDCON
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-0 0-00 40, 233
ECCP1DEL
PRSEN
PDC6
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
0000 0000 40, 187
TXERRCNT
TEC7
TEC6
TEC5
TEC4
TEC3
TEC2
TEC1
TEC0
0000 0000 40, 288
RXERRCNT
REC7
REC6
REC5
REC4
REC3
REC2
REC1
REC0
0000 0000 40, 296
COMSTAT
Mode 0
RXB0OVFL
RXB1OVFL
TXBO
TXBP
RXBP
TXWARN
RXWARN
EWARN
0000 0000 40, 284
COMSTAT
Mode 1
—
RXBnOVFL
TXBO
TXBP
RXBP
TXWARN
RXWARN
EWARN
-000 0000 40, 284
FIFOEMPTY RXBnOVFL
TXBO
TXBP
RXBP
TXWARN
RXWARN
EWARN
0000 0000 40, 284
—
—
0000 ---- 40, 318
COMSTAT
Mode 2
CIOCON
TX2SRC
TX2EN
ENDRHI
CANCAP
—
—
BRGCON3
WAKDIS
WAKFIL
—
—
—
SEG2PH2
SEG2PH1 SEG2PH0 00-- -000 40, 317
BRGCON2
SEG2PHT
SAM
SEG1PH2
SEG1PH1
SEG1PH0
PRSEG2
PRSEG1
PRSEG0
0000 0000 40, 317
BRGCON1
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
0000 0000 40, 317
CANCON
Mode 0
REQOP2
REQOP1
REQOP0
ABAT
WIN2
WIN1
WIN0
—
1000 000- 40, 239
CANCON
Mode 1
REQOP2
REQOP1
REQOP0
ABAT
—
—
—
—
1000 ---- 40, 239
CANCON
Mode 2
REQOP2
REQOP1
REQOP0
ABAT
FP3
FP2
FP1
FP0
1000 0000 40, 239
CANSTAT
Mode 0
OPMODE2
OPMODE1
OPMODE0
—
ICODE2
ICODE1
ICODE0
—
000- 0000 40, 239
CANSTAT
Modes 0, 1
OPMODE2
OPMODE1
OPMODE0
EICODE4
EICODE3
EICODE2
EICODE1
EICODE0 0000 0000 40, 239
MDSEL1
MDSEL0
FIFOWM
EWIN4
EWIN3
EWIN2
EWIN1
RXB0D7
RXB0D77
RXB0D76
RXB0D75
RXB0D74
RXB0D73
RXB0D72
RXB0D71
RXB0D70 xxxx xxxx 40, 230
RXB0D6
RXB0D67
RXB0D66
RXB0D65
RXB0D64
RXB0D63
RXB0D62
RXB0D61
RXB0D60 xxxx xxxx 40, 230
RXB0D5
RXB0D57
RXB0D56
RXB0D55
RXB0D54
RXB0D53
RXB0D52
RXB0D51
RXB0D50 xxxx xxxx 40, 230
RXB0D4
RXB0D47
RXB0D46
RXB0D45
RXB0D44
RXB0D43
RXB0D42
RXB0D41
RXB0D40 xxxx xxxx 40, 230
RXB0D3
RXB0D37
RXB0D36
RXB0D35
RXB0D34
RXB0D33
RXB0D32
RXB0D31
RXB0D30 xxxx xxxx 40, 230
RXB0D2
RXB0D27
RXB0D26
RXB0D25
RXB0D24
RXB0D23
RXB0D22
RXB0D21
RXB0D20 xxxx xxxx 40, 230
RXB0D1
RXB0D17
RXB0D16
RXB0D15
RXB0D14
RXB0D13
RXB0D12
RXB0D11
RXB0D10 xxxx xxxx 40, 230
RXB0D07
RXB0D06
RXB0D05
RXB0D04
RXB0D03
RXB0D02
RXB0D01
RXB0D00 xxxx xxxx 40, 230
RXB0D0
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
EWIN0
0001 0000 40, 323
ECANCON
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
DS30491D-page 70
2003-2013 Microchip Technology Inc.
18F8680.book Page 71 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
RXB0DLC
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 40, 230
RXB0EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 41, 230
RXB0EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 41, 230
RXB0SIDL
SID2
SID1
SID0
SRR
EXID
—
EID17
EID16
xxxx x-xx 41, 230
RXB0SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 41, 230
RXB0CON
Mode 0
RXFUL
RXM1
RXM0(4)
—(4)
RXB0CON
Mode 1, 2
RXFUL
RXM1
RTRR0(4)
FILHIT4(4)
FILHIT3(4)
FILHIT2(4)
FILHIT1(4) FILHIT0(4) 0000 0000 41, 230
RXB1D7
RXB1D77
RXB1D76
RXB1D75
RXB1D74
RXB1D73
RXB1D72
RXB1D71
RXB1D70 xxxx xxxx 41, 230
RXB1D6
RXB1D67
RXB1D66
RXB1D65
RXB1D64
RXB1D63
RXB1D62
RXB1D61
RXB1D60 xxxx xxxx 41, 230
RXB1D5
RXB1D57
RXB1D56
RXB1D55
RXB1D54
RXB1D53
RXB1D52
RXB1D51
RXB1D50 xxxx xxxx 41, 230
RXB1D4
RXB1D47
RXB1D46
RXB1D45
RXB1D44
RXB1D43
RXB1D42
RXB1D41
RXB1D40 xxxx xxxx 41, 230
RXB1D3
RXB1D37
RXB1D36
RXB1D35
RXB1D34
RXB1D33
RXB1D32
RXB1D31
RXB1D30 xxxx xxxx 41, 230
RXB1D2
RXB1D27
RXB1D26
RXB1D25
RXB1D24
RXB1D23
RXB1D22
RXB1D21
RXB1D20 xxxx xxxx 41, 230
RXB1D1
RXB1D17
RXB1D16
RXB1D15
RXB1D14
RXB1D13
RXB1D12
RXB1D11
RXB1D10 xxxx xxxx 41, 230
RXB1D0
RXB1D00 xxxx xxxx 41, 230
RXRTRR0(4) RXB0DBEN(4) JTOFF(4)
FILHIT0(4) 000- 0000 41, 230
RXB1D07
RXB1D06
RXB1D05
RXB1D04
RXB1D03
RXB1D02
RXB1D01
RXB1DLC
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 41, 230
RXB1EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 41, 230
RXB1EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 41, 230
RXB1SIDL
SID2
SID1
SID0
SRR
EXID
—
EID17
EID16
xxxx x-xx 41, 230
RXB1SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 41, 230
RXB1CON
Mode 0
RXFUL
RXM1
RXM0(4)
—(4)
RXRTRR0(4)
FILHIT2(4)
FILHIT1(4) FILHIT0(4) 000- 0000 41, 230
RXB1CON
Mode 1, 2
RXFUL
RXM1
RTRRO(4)
FILHIT4(4)
FILHIT3(4)
FILHIT2(4)
FILHIT1(4) FILHIT0(4) 0000 0000 41, 230
TXB0D7
TXB0D77
TXB0D76
TXB0D75
TXB0D74
TXB0D73
TXB0D72
TXB0D71
TXB0D70 xxxx xxxx 41, 230
TXB0D6
TXB0D67
TXB0D66
TXB0D65
TXB0D64
TXB0D63
TXB0D62
TXB0D61
TXB0D60 xxxx xxxx 41, 230
TXB0D5
TXB0D57
TXB0D56
TXB0D55
TXB0D54
TXB0D53
TXB0D52
TXB0D51
TXB0D50 xxxx xxxx 41, 230
TXB0D4
TXB0D47
TXB0D46
TXB0D45
TXB0D44
TXB0D43
TXB0D42
TXB0D41
TXB0D40 xxxx xxxx 41, 230
TXB0D3
TXB0D37
TXB0D36
TXB0D35
TXB0D34
TXB0D33
TXB0D32
TXB0D31
TXB0D30 xxxx xxxx 41, 230
TXB0D2
TXB0D27
TXB0D26
TXB0D25
TXB0D24
TXB0D23
TXB0D22
TXB0D21
TXB0D20 xxxx xxxx 41, 230
TXB0D1
TXB0D17
TXB0D16
TXB0D15
TXB0D14
TXB0D13
TXB0D12
TXB0D11
TXB0D10 xxxx xxxx 41, 230
TXB0D0
TXB0D00 xxxx xxxx 41, 230
TXB0D07
TXB0D06
TXB0D05
TXB0D04
TXB0D03
TXB0D02
TXB0D01
TXB0DLC
—
TXRTR
—
—
DLC3
DLC2
DLC1
DLC0
-x-- xxxx 41, 230
TXB0EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 41, 230
TXB0EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 41, 230
TXB0SIDL
SID2
SID1
SID0
—
EXIDE
—
EID17
EID16
xx-x x-xx 41, 230
TXB0SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 42, 230
TXB0CON
Mode 0
—
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
-000 0-00 42, 230
TXB0CON
Mode 1, 2
TXBIF
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
0000 0-00 42, 230
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 71
18F8680.book Page 72 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
TXB1D7
TXB1D77
TXB1D76
TXB1D75
TXB1D74
TXB1D73
TXB1D72
TXB1D71
TXB1D70 xxxx xxxx 42, 230
TXB1D6
TXB1D67
TXB1D66
TXB1D65
TXB1D64
TXB1D63
TXB1D62
TXB1D61
TXB1D60 xxxx xxxx 42, 230
TXB1D5
TXB1D57
TXB1D56
TXB1D55
TXB1D54
TXB1D53
TXB1D52
TXB1D51
TXB1D50 xxxx xxxx 42, 230
TXB1D4
TXB1D47
TXB1D46
TXB1D45
TXB1D44
TXB1D43
TXB1D42
TXB1D41
TXB1D40 xxxx xxxx 42, 230
TXB1D3
TXB1D37
TXB1D36
TXB1D35
TXB1D34
TXB1D33
TXB1D32
TXB1D31
TXB1D30 xxxx xxxx 42, 230
TXB1D2
TXB1D27
TXB1D26
TXB1D25
TXB1D24
TXB1D23
TXB1D22
TXB1D21
TXB1D20 xxxx xxxx 42, 230
TXB1D1
TXB1D17
TXB1D16
TXB1D15
TXB1D14
TXB1D13
TXB1D12
TXB1D11
TXB1D10 xxxx xxxx 42, 230
TXB1D0
TXB1D00 xxxx xxxx 42, 230
TXB1D07
TXB1D06
TXB1D05
TXB1D04
TXB1D03
TXB1D02
TXB1D01
TXB1DLC
—
TXRTR
—
—
DLC3
DLC2
DLC1
DLC0
-x-- xxxx 42, 230
TXB1EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 42, 230
TXB1EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 42, 230
TXB1SIDL
SID2
SID1
SID0
—
EXIDE
—
EID17
EID16
xx-x x-xx 42, 230
TXB1SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 42, 230
TXB1CON
Mode 0
—
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
-000 0-00 42, 230
TXB1CON
Mode 1, 2
TXBIF
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
0000 0-00 42, 230
TXB2D7
TXB2D77
TXB2D76
TXB2D75
TXB2D74
TXB2D73
TXB2D72
TXB2D71
TXB2D70 xxxx xxxx 42, 230
TXB2D6
TXB2D67
TXB2D66
TXB2D65
TXB2D64
TXB2D63
TXB2D62
TXB2D61
TXB2D60 xxxx xxxx 42, 230
TXB2D5
TXB2D57
TXB2D56
TXB2D55
TXB2D54
TXB2D53
TXB2D52
TXB2D51
TXB2D50 xxxx xxxx 42, 230
TXB2D4
TXB2D47
TXB2D46
TXB2D45
TXB2D44
TXB2D43
TXB2D42
TXB2D41
TXB2D40 xxxx xxxx 42, 230
TXB2D3
TXB2D37
TXB2D36
TXB2D35
TXB2D34
TXB2D33
TXB2D32
TXB2D31
TXB2D30 xxxx xxxx 42, 230
TXB2D2
TXB2D27
TXB2D26
TXB2D25
TXB2D24
TXB2D23
TXB2D22
TXB2D21
TXB2D20 xxxx xxxx 42, 230
TXB2D1
TXB2D17
TXB2D16
TXB2D15
TXB2D14
TXB2D13
TXB2D12
TXB2D11
TXB2D10 xxxx xxxx 42, 230
TXB2D0
TXB2D00 xxxx xxxx 42, 230
TXB2D07
TXB2D06
TXB2D05
TXB2D04
TXB2D03
TXB2D02
TXB2D01
TXB2DLC
—
TXRTR
—
—
DLC3
DLC2
DLC1
DLC0
-x-- xxxx 42, 230
TXB2EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 42, 230
TXB2EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 42, 230
TXB2SIDL
SID2
SID1
SID0
—
EXIDE
—
EID17
EID16
xxx- x-xx 42, 230
TXB2SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 42, 230
TXB2CON
Mode 0
—
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
-000 0-00 42, 230
TXB2CON
Mode 1, 2
TXBIF
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
0000 0-00 42, 230
RXM1EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 42, 230
RXM1EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXM1SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x 0-xx 43, 230
RXM1SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXM0EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXM0EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXM0SIDL
SID2
SID1
SID0
—
EXIDM
—
EID17
EID16
xx-x 0-xx 43, 230
RXM0SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXF15EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
DS30491D-page 72
2003-2013 Microchip Technology Inc.
18F8680.book Page 73 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
REGISTER FILE SUMMARY (CONTINUED)
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
RXF15EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 47, 230
RXF15SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 47, 230
RXF15SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 47, 230
RXF14EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
RXF14EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 47, 230
RXF14SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 47, 230
RXF14SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 47, 230
RXF13EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
RXF13EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 47, 230
RXF13SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 47, 230
RXF13SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 47, 230
RXF12EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
RXF12EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 47, 230
RXF12SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 47, 230
RXF12SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 47, 230
RXF11EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
RXF11EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 47, 230
RXF11SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 47, 230
RXF11SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 47, 230
RXF10EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
RXF10EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 47, 230
RXF10SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 48, 230
RXF10SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 48, 230
RXF9EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 47, 230
RXF9EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 48, 230
RXF9SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 48, 230
RXF9SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 48, 230
RXF8EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 48, 230
RXF8EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 48, 230
RXF8SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 48, 230
RXF8SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 48, 230
RXF7EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 48, 230
RXF7EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 48, 230
RXF7SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 48, 230
RXF7SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 48, 230
RXF6EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 48, 230
RXF6EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 48, 230
RXF6SIDL(7)
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 48, 230
RXF6SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 48, 230
RXF5EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXF5EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 73
18F8680.book Page 74 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
RXF5SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 43, 230
RXF5SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXF4EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXF4EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXF4SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 43, 230
RXF4SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXF3EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXF3EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXF3SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 43, 230
RXF3SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXF2EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXF2EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXF2SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 43, 230
RXF2SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXF1EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXF1EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXF1SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 43, 230
RXF1SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
RXF0EIDL
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 43, 230
RXF0EIDH
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 43, 230
RXF0SIDL
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
xx-x x-xx 43, 230
RXF0SIDH
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 43, 230
B5D7(7)
B5D77
B5D76
B5D75
B5D74
B5D73
B5D72
B5D71
B5D70
xxxx xxxx 44, 230
B5D6(7)
B5D67
B5D66
B5D65
B5D64
B5D63
B5D62
B5D61
B5D60
xxxx xxxx 44, 230
B5D5(7)
B5D57
B5D56
B5D55
B5D54
B5D53
B5D52
B5D51
B5D50
xxxx xxxx 44, 230
B5D4(7)
B5D47
B5D46
B5D45
B5D44
B5D43
B5D42
B5D41
B5D40
xxxx xxxx 44, 230
B5D3(7)
B5D37
B5D36
B5D35
B5D34
B5D33
B5D32
B5D31
B5D30
xxxx xxxx 44, 230
B5D2(7)
B5D27
B5D26
B5D25
B5D24
B5D23
B5D22
B5D21
B5D20
xxxx xxxx 44, 230
B5D1(7)
B5D17
B5D16
B5D15
B5D14
B5D13
B5D12
B5D11
B5D10
xxxx xxxx 44, 230
B5D0(7)
B5D07
B5D06
B5D05
B5D04
B5D03
B5D02
B5D01
B5D00
xxxx xxxx 44, 230
B5DLC(7)
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 44, 230
B5EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 44, 230
B5EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 44, 230
B5SIDL(7)
SID2
SID1
SID0
SRR
EXID/
EXIDE(5)
—
EID17
EID16
xxxx x-xx 44, 230
B5SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 44, 230
B5CON(5, 7)
RXFUL/
TXBIF
RXM1/
TXABT
RTRRO/
TXLARB
FILHIT4/
TXERR
FILHIT3/
TXREQ
FILHIT2/
RTREN
FILHIT1/
TXPRI1
FILHIT0/
TXPRI0
0000 0000 44, 230
B4D7(7)
B4D77
B4D76
B4D75
B4D74
B4D73
B4D72
B4D71
B4D70
xxxx xxxx 44, 230
B4D6(7)
B4D67
B4D66
B4D65
B4D64
B4D63
B4D62
B4D61
B4D60
xxxx xxxx 44, 230
B4D5(7)
B4D57
B4D56
B4D55
B4D54
B4D53
B4D52
B4D51
B4D50
xxxx xxxx 44, 230
B4D4(7)
B4D47
B4D46
B4D45
B4D44
B4D43
B4D42
B4D41
B4D40
xxxx xxxx 44, 230
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
DS30491D-page 74
2003-2013 Microchip Technology Inc.
18F8680.book Page 75 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
B4D3(7)
B4D37
B4D36
B4D35
B4D34
B4D33
B4D32
B4D31
B4D30
xxxx xxxx 44, 230
B4D2(7)
B4D27
B4D26
B4D25
B4D24
B4D23
B4D22
B4D21
B4D20
xxxx xxxx 44, 230
B4D1(7)
B4D17
B4D16
B4D15
B4D14
B4D13
B4D12
B4D11
B4D10
xxxx xxxx 44, 230
B4D0(7)
B4D07
B4D06
B4D05
B4D04
B4D03
B4D02
B4D01
B4D00
xxxx xxxx 44, 230
B4DLC(7)
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 44, 230
B4EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 44, 230
B4EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 44, 230
B4SIDL(7)
SID2
SID1
SID0
SRR
EXID/
EXIDE(5)
—
EID17
EID16
xxxx x-xx 44, 230
B4SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 44, 230
B4CON(5, 7)
RXFUL/
TXB3IF
RXM1/
TXABT
RTRRO/
TXLARB
FILHIT4/
TXERR
FILHIT3/
TXREQ
FILHIT2/
RTREN
FILHIT1/
TXPRI1
FILHIT0/
TXPRI0
0000 0000 44, 230
B3D7(7)
B3D77
B3D76
B3D75
B3D74
B3D73
B3D72
B3D71
B3D70
xxxx xxxx 44, 230
B3D6(7)
B3D67
B3D66
B3D65
B3D64
B3D63
B3D62
B3D61
B3D60
xxxx xxxx 44, 230
B3D5(7)
B3D57
B3D56
B3D55
B3D54
B3D53
B3D52
B3D51
B3D50
xxxx xxxx 44, 230
B3D4(7)
B3D47
B3D46
B3D45
B3D44
B3D43
B3D42
B3D41
B3D40
xxxx xxxx 45, 230
B3D3(7)
B3D37
B3D36
B3D35
B3D34
B3D33
B3D32
B3D31
B3D30
xxxx xxxx 45, 230
B3D2(7)
B3D27
B3D26
B3D25
B3D24
B3D23
B3D22
B3D21
B3D20
xxxx xxxx 45, 230
B3D1(7)
B3D17
B3D16
B3D15
B3D14
B3D13
B3D12
B3D11
B3D10
xxxx xxxx 45, 230
B3D0(7)
B3D07
B3D06
B3D05
B3D04
B3D03
B3D02
B3D01
B3D00
xxxx xxxx 45, 230
B3DLC(7)
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 45, 230
B3EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 45, 230
B3EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 45, 230
B3SIDL(7)
SID2
SID1
SID0
SRR
EXID/
EXIDE(5)
—
EID17
EID16
xxxx x-xx 45, 230
B3SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 45, 230
B3CON(5, 7)
RXFUL/
TXBIF
RXM1/
TXABT
RTRRO/
TXLARB
FILHIT4/
TXERR
FILHIT3/
TXREQ
FILHIT2/
RTREN
FILHIT1/
TXPRI1
FILHIT0/
TXPRI0
0000 0000 45, 230
B2D7(7)
B2D77
B2D76
B2D75
B2D74
B2D73
B2D72
B2D71
B2D70
xxxx xxxx 45, 230
B2D6(7)
B2D67
B2D66
B2D65
B2D64
B2D63
B2D62
B2D61
B2D60
xxxx xxxx 45, 230
B2D5(7)
B2D57
B2D56
B2D55
B2D54
B2D53
B2D52
B2D51
B2D50
xxxx xxxx 45, 230
B2D4(7)
B2D47
B2D46
B2D45
B2D44
B2D43
B2D42
B2D41
B2D40
xxxx xxxx 45, 230
B2D3(7)
B2D37
B2D36
B2D35
B2D34
B2D33
B2D32
B2D31
B2D30
xxxx xxxx 45, 230
B2D2(7)
B2D27
B2D26
B2D25
B2D24
B2D23
B2D22
B2D21
B2D20
xxxx xxxx 45, 230
B2D1(7)
B2D17
B2D16
B2D15
B2D14
B2D13
B2D12
B2D11
B2D10
xxxx xxxx 45, 230
B2D0(7)
B2D07
B2D06
B2D05
B2D04
B2D03
B2D02
B2D01
B2D00
xxxx xxxx 45, 230
B2DLC(7)
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 45, 230
B2EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 45, 230
B2EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 45, 230
B2SIDL(7)
SID2
SID1
SID0
SRR
EXID/
EXIDE(5)
—
EID17
EID16
xxxx x-xx 45, 230
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 45, 230
B2SIDH(7)
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
2003-2013 Microchip Technology Inc.
DS30491D-page 75
18F8680.book Page 76 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 4-3:
File Name
B2CON(5, 7)
REGISTER FILE SUMMARY (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
RXFUL/
TXBIF
RXM1/
TXABT
RTRRO/
TXLARB
FILHIT4/
TXERR
FILHIT3/
TXREQ
FILHIT2/
RTREN
FILHIT1/
TXPRI1
FILHIT0/
TXPRI0
0000 0000 45, 230
(7)
B1D7
B1D77
B1D76
B1D75
B1D74
B1D73
B1D72
B1D71
B1D70
xxxx xxxx 45, 230
B1D6(7)
B1D67
B1D66
B1D65
B1D64
B1D63
B1D62
B1D61
B1D60
xxxx xxxx 45, 230
B1D5(7)
B1D57
B1D56
B1D55
B1D54
B1D53
B1D52
B1D51
B1D50
xxxx xxxx 45, 230
B1D4(7)
B1D47
B1D46
B1D45
B1D44
B1D43
B1D42
B1D41
B1D40
xxxx xxxx 45, 230
B1D3(7)
B1D37
B1D36
B1D35
B1D34
B1D33
B1D32
B1D31
B1D30
xxxx xxxx 45, 230
B1D2(7)
B1D27
B1D26
B1D25
B1D24
B1D23
B1D22
B1D21
B1D20
xxxx xxxx 45, 230
B1D1(7)
B1D17
B1D16
B1D15
B1D14
B1D13
B1D12
B1D11
B1D10
xxxx xxxx 46, 230
B1D0(7)
B1D07
B1D06
B1D05
B1D04
B1D03
B1D02
B1D01
B1D00
xxxx xxxx 46, 230
B1DLC(7)
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 46, 230
B1EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 46, 230
B1EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 46, 230
B1SIDL(7)
SID2
SID1
SID0
SRR
EXID
—
EID17
EID16
xxxx x-xx 46, 230
B1SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 46, 230
B1CON(5, 7)
RXFUL/
TXBIF
RXM1/
TXABT
RTRRO/
TXLARB
FILHIT4/
TXERR
FILHIT3/
TXREQ
FILHIT2/
RTREN
FILHIT1/
TXPRI1
FILHIT0/
TXPRI0
0000 0000 46, 230
B0D7(7)
B0D77
B0D76
B0D75
B0D74
B0D73
B0D72
B0D71
B0D70
xxxx xxxx 46, 230
B0D6(7)
B0D67
B0D66
B0D65
B0D64
B0D63
B0D62
B0D61
B0D60
xxxx xxxx 46, 230
B0D5(7)
B0D57
B0D56
B0D55
B0D54
B0D53
B0D52
B0D51
B0D50
xxxx xxxx 46, 230
B0D4(7)
B0D47
B0D46
B0D45
B0D44
B0D43
B0D42
B0D41
B0D40
xxxx xxxx 46, 230
B0D3(7)
B0D37
B0D36
B0D35
B0D34
B0D33
B0D32
B0D31
B0D30
xxxx xxxx 46, 230
B0D2(7)
B0D27
B0D26
B0D25
B0D24
B0D23
B0D22
B0D21
B0D20
xxxx xxxx 46, 230
B0D1(7)
B0D17
B0D16
B0D15
B0D14
B0D13
B0D12
B0D11
B0D10
xxxx xxxx 46, 230
B0D0(7)
B0D07
B0D06
B0D05
B0D04
B0D03
B0D02
B0D01
B0D00
xxxx xxxx 46, 230
B0DLC(7)
—
RTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
-xxx xxxx 46, 230
B0EIDL(7)
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
xxxx xxxx 46, 230
B0EIDH(7)
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
xxxx xxxx 46, 230
B0SIDL(7)
SID2
SID1
SID0
SRR
EXID
—
EID17
EID16
xxxx x-xx 46, 230
B0SIDH(7)
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
xxxx xxxx 46, 230
RXFUL/
TXBIF
RXM1/
TXABT
RTRRO/
TXLARB
FILHIT4/
TXERR
FILHIT3/
TXREQ
FILHIT2/
RTREN
FILHIT1/
TXPRI1
FILHIT0/
TXPRI0
0000 0000 46, 230
B0CON(5, 7)
(7)
TXBIE
—
—
—
TXB2IE
TXB1IE
TXB0IE
—
—
---0 00-- 46, 230
BIE0(7)
B5IE
B4IE
B3IE
B2IE
B1IE
B0IE
RXB1IE
RXB0IE
0000 0000 46, 230
BSEL0(7)
B5TXEN
B4TXEN
B3TXEN
B2TXEN
B1TXEN
B0TXEN
—
—
0000 00-- 46, 230
MSEL3(7)
FIL15_1
FIL15_0
FIL14_1
FIL14_0
FIL13_1
FIL13_0
FIL12_1
FIL12_0
0000 0000 46, 230
MSEL2(7)
FIL11_1
FIL11_0
FIL10_1
FIL10_0
FIL9_1
FIL9_0
FIL8_1
FIL8_0
0000 0000 46, 230
MSEL1(7)
FIL7_1
FIL7_0
FIL6_1
FIL6_0
FIL5_1
FIL5_0
FIL4_1
FIL4_0
0000 0101 46, 230
MSEL0(7)
FIL3_1
FIL3_0
FIL2_1
FIL2_0
FIL1_1
FIL1_0
FIL0_1
FIL0_0
0101 0000 46, 230
SDFLC(7)
—
—
—
DFLC4
DFLC3
DFLC2
DFLC1
DFLC0
---0 0000 46, 230
RXFCON1(7)
RXF15EN
RXF14EN
RXF13EN
RXF12EN
RXF11EN
RXF10EN
RXF9EN
RXF8EN
0000 0000 46, 230
RXFCON0(7)
RXF7EN
RXF6EN
RXF5EN
RXF4EN
RXF3EN
RXF2EN
RXF1EN
RXF0EN
0011 1111 47, 230
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
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TABLE 4-3:
REGISTER FILE SUMMARY (CONTINUED)
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Details
POR, BOR on page:
RXFBCON7(7)
F15BP_3
F15BP_2
F15BP_1
F15BP_0
F14BP_3
F14BP_2
F14BP_1
RXFBCON6(7)
F13BP_3
F13BP_2
F13BP_1
F13BP_0
F12BP_3
F12BP_2
F12BP_1
F12BP_01 0000 0000 47, 230
RXFBCON5(7)
F11BP_3
F11BP_2
F11BP_1
F11BP_0
F10BP_3
F10BP_2
F10BP_1
F10BP_01 0000 0000 47, 230
RXFBCON4(7)
F9BP_3
F9BP_2
F9BP_1
F9BP_0
F8BP_3
F8BP_2
F8BP_1
F8BP_01
0000 0000 47, 230
RXFBCON3(7)
F7BP_3
F7BP_2
F7BP_1
F7BP_0
F6BP_3
F6BP_2
F6BP_1
F6BP_01
0000 0000 47, 230
RXFBCON2(7)
F5BP_3
F5BP_2
F5BP_1
F5BP_0
F4BP_3
F4BP_2
F4BP_1
F4BP_01
0000 0000 47, 230
RXFBCON1(7)
F3BP_3
F3BP_2
F3BP_1
F3BP_0
F2BP_3
F2BP_2
F2BP_1
F2BP_01
0000 0000 47, 230
RXFBCON0(7)
F1BP_3
F1BP_2
F1BP_1
F1BP_0
F0BP_3
F0BP_2
F0BP_1
F0BP_01
0000 0000 47, 230
Legend:
Note 1:
2:
3:
4:
5:
6:
7:
F14BP_01 0000 0000 47, 230
x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read ‘0’ in all other oscillator
modes.
Bit 21 of the TBLPTRU allows access to the device configuration bits.
These registers are unused on PIC18F6X80 devices; always maintain these clear.
These bits have multiple functions depending on the CAN module mode selection.
Meaning of this register depends on whether this buffer is configured as transmit or receive.
RG5 is available as an input when MCLR is disabled.
This register reads all ‘0’s until the ECAN module is set up in Mode 1 or Mode 2.
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4.10
Access Bank
4.11
The Access Bank is an architectural enhancement
which is very useful for C compiler code optimization.
The techniques used by the C compiler may also be
useful for programs written in assembly.
This data memory region can be used for:
•
•
•
•
•
BSR holds the upper 4 bits of the 12-bit RAM
address. The BSR bits will always read ‘0’s and
writes will have no effect.
Intermediate computational values
Local variables of subroutines
Faster context saving/switching of variables
Common variables
Faster evaluation/control of SFRs (no banking)
A MOVLB instruction has been provided in the
instruction set to assist in selecting banks.
If the currently selected bank is not implemented, any
read will return all ‘0’s and all writes are ignored. The
Status register bits will be set/cleared as appropriate for
the instruction performed.
The Access Bank is comprised of the upper 160 bytes
in Bank 15 (SFRs) and the lower 96 bytes in Bank 0.
These two sections will be referred to as Access RAM
High and Access RAM Low, respectively. Figure 4-7
indicates the Access RAM areas.
Each Bank extends up to 0FFh (256 bytes). All data
memory is implemented as static RAM.
A bit in the instruction word specifies if the operation is
to occur in the bank specified by the BSR register or in
the Access Bank. This bit is denoted by the ‘a’ bit (for
access bit).
A MOVFF instruction ignores the BSR since the 12-bit
addresses are embedded into the instruction word.
Section 4.12 “Indirect Addressing, INDF and FSR
Registers” provides a description of indirect addressing which allows linear addressing of the entire RAM
space.
When forced in the Access Bank (a = 0), the last
address in Access RAM Low is followed by the first
address in Access RAM High. Access RAM High maps
the Special Function Registers so that these registers
can be accessed without any software overhead. This is
useful for testing status flags and modifying control bits.
FIGURE 4-8:
Bank Select Register (BSR)
The need for a large general purpose memory space
dictates a RAM banking scheme. The data memory is
partitioned into sixteen banks. When using direct
addressing, the BSR should be configured for the
desired bank.
DIRECT ADDRESSING
Direct Addressing
BSR
Bank Select(2)
7
From Opcode(3)
0
Location Select(3)
00h
01h
0Eh
0Fh
000h
100h
E00h
F00h
0FFh
1FFh
EFFh
FFFh
Bank 14
Bank 15
Data
Memory(1)
Bank 0
Bank 1
Note 1: For register file map detail, see Table 4-2.
2: The access bit of the instruction can be used to force an override of the selected bank (BSR) to the
registers of the Access Bank.
3: The MOVFF instruction embeds the entire 12-bit address in the instruction.
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4.12
Indirect Addressing, INDF and
FSR Registers
Indirect addressing is a mode of addressing data memory where the data memory address in the instruction
is not fixed. An FSR register is used as a pointer to the
data memory location that is to be read or written. Since
this pointer is in RAM, the contents can be modified by
the program. This can be useful for data tables in the
data memory and for software stacks. Figure 4-9
shows the operation of indirect addressing. This shows
the moving of the value to the data memory address
specified by the value of the FSR register.
Indirect addressing is possible by using one of the
INDF registers. Any instruction using the INDF register
actually accesses the register pointed to by the File
Select Register, FSR. Reading the INDF register itself,
indirectly (FSR = 0), will read 00h. Writing to the INDF
register indirectly, results in a no operation. The FSR
register contains a 12-bit address which is shown in
Figure 4-10.
The INDFn register is not a physical register. Addressing INDFn actually addresses the register whose
address is contained in the FSRn register (FSRn is a
pointer). This is indirect addressing.
Example 4-4 shows a simple use of indirect addressing
to clear the RAM in Bank 1 (locations 100h-1FFh) in a
minimum number of instructions.
EXAMPLE 4-4:
NEXT
LFSR
CLRF
HOW TO CLEAR RAM
(BANK 1) USING
INDIRECT ADDRESSING
FSR0, 100h
POSTINC0
BTFSS FSR0H, 1
BRA
CONTINUE
NEXT
;
;
;
;
;
;
;
;
Clear INDF
register and
inc pointer
All done with
Bank1?
NO, clear next
YES, continue
There are three Indirect Addressing registers. To
address the entire data memory space (4096 bytes),
these registers are 12-bits wide. To store the 12 bits of
addressing information, two 8-bit registers are
required. These Indirect Addressing registers are:
1.
2.
3.
FSR0: composed of FSR0H:FSR0L
FSR1: composed of FSR1H:FSR1L
FSR2: composed of FSR2H:FSR2L
In addition, there are registers INDF0, INDF1 and
INDF2 which are not physically implemented. Reading
or writing to these registers activates indirect addressing with the value in the corresponding FSR register
being the address of the data. If an instruction writes a
value to INDF0, the value will be written to the address
pointed to by FSR0H:FSR0L. A read from INDF1 reads
2003-2013 Microchip Technology Inc.
the data from the address pointed to by
FSR1H:FSR1L. INDFn can be used in code anywhere
an operand can be used.
If INDF0, INDF1, or INDF2 are read indirectly via an
FSR, all ‘0’s are read (zero bit is set). Similarly, if
INDF0, INDF1, or INDF2 are written to indirectly, the
operation will be equivalent to a NOP instruction and the
Status bits are not affected.
4.12.1
INDIRECT ADDRESSING
OPERATION
Each FSR register has an INDF register associated
with it plus four additional register addresses.
Performing an operation on one of these five registers
determines how the FSR will be modified during
indirect addressing.
When data access is done to one of the five INDFn
locations, the address selected will configure the FSRn
register to:
• Do nothing to FSRn after an indirect access (no
change) – INDFn.
• Auto-decrement FSRn after an indirect access
(post-decrement) – POSTDECn.
• Auto-increment FSRn after an indirect access
(post-increment) – POSTINCn.
• Auto-increment FSRn before an indirect access
(pre-increment) – PREINCn.
• Use the value in the WREG register as an offset
to FSRn. Do not modify the value of the WREG or
the FSRn register after an indirect access (no
change) – PLUSWn.
When using the auto-increment or auto-decrement features, the effect on the FSR is not reflected in the Status
register. For example, if the indirect address causes the
FSR to equal ‘0’, the Z bit will not be set.
Incrementing or decrementing an FSR affects all
12 bits. That is, when FSRnL overflows from an
increment, FSRnH will be incremented automatically.
Adding these features allows the FSRn to be used as a
stack pointer in addition to its uses for table operations
in data memory.
Each FSR has an address associated with it that
performs an indexed indirect access. When a data
access to this INDFn location (PLUSWn) occurs, the
FSRn is configured to add the signed value in the
WREG register and the value in FSR to form the
address before an indirect access. The FSR value is
not changed.
If an FSR register contains a value that points to one of
the INDFn, an indirect read will read 00h (zero bit is
set), while an indirect write will be equivalent to a NOP
(Status bits are not affected).
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If an indirect addressing operation is done where the
target address is an FSRnH or FSRnL register, the
write operation will dominate over the pre- or
post-increment/decrement functions.
FIGURE 4-9:
INDIRECT ADDRESSING OPERATION
RAM
0h
Instruction
Executed
Opcode
Address
0FFFh
12
File Address = Access of an Indirect Addressing Register
BSR
Instruction
Fetched
4
Opcode
FIGURE 4-10:
12
12
8
FSR
File
INDIRECT ADDRESSING
Indirect Addressing
11
FSR Register
0
Location Select
0000h
Data
Memory(1)
0FFFh
Note 1: For register file map detail, see Table 4-2.
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4.13
Status Register
The Status register, shown in Register 4-3, contains the
arithmetic status of the ALU. The Status register can be
the destination for any instruction as with any other register. If the Status register is the destination for an
instruction that affects the Z, DC, C, OV or N bits, then
the write to these five bits is disabled. These bits are set
or cleared according to the device logic. Therefore, the
result of an instruction with the Status register as
destination may be different than intended.
REGISTER 4-3:
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the Status register
as 000u u1uu (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF, MOVFF and MOVWF instructions are used to
alter the Status register because these instructions do
not affect the Z, C, DC, OV or N bits from the Status
register. For other instructions not affecting any status
bits, see Table 25-2.
Note:
The C and DC bits operate as a borrow and
digit borrow bit respectively, in subtraction.
STATUS REGISTER
U-0
U-0
U-0
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
—
—
—
N
OV
Z
DC
C
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4
N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was
negative (ALU MSB = 1).
1 = Result was negative
0 = Result was positive
bit 3
OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the
7-bit magnitude which causes the sign bit (bit 7) to change state.
1 = Overflow occurred for signed arithmetic (in this arithmetic operation)
0 = No overflow occurred
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
For ADDWF, ADDLW, SUBLW, and SUBWF instructions:
1 = A carry-out from the 4th low order bit of the result occurred
0 = No carry-out from the 4th low order bit of the result
Note:
bit 0
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit
is loaded with either the bit 4 or bit 3 of the source register.
C: Carry/borrow bit
For ADDWF, ADDLW, SUBLW, and SUBWF instructions:
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Note:
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’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:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
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x = Bit is unknown
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4.14
RCON Register
Note 1: It is recommended that the POR bit be set
after a Power-on Reset has been
detected so that subsequent Power-on
Resets may be detected.
The Reset Control (RCON) register contains flag bits
that allow differentiation between the sources of a
device Reset. These flags include the TO, PD, POR,
BOR and RI bits. This register is readable and writable.
REGISTER 4-4:
2: Brown-out Reset is said to have occurred
when BOR is ‘0’ and POR is ‘1’ (assuming that POR was set to ‘1’ by software
immediately after POR).
RCON REGISTER
R/W-0
U-0
U-0
R/W-1
R/W-1
R/W-1
R/W-0
R/W-0
IPEN
—
—
RI
TO
PD
POR
BOR
bit 7
bit 0
bit 7
IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (PIC16CXXX Compatibility mode)
bit 6-5
Unimplemented: Read as ‘0’
bit 4
RI: RESET Instruction Flag bit
1 = The RESET instruction was not executed
0 = The RESET instruction was executed causing a device Reset
(must be set in software after a Brown-out Reset occurs)
bit 3
TO: Watchdog Time-out Flag bit
1 = After power-up, CLRWDT instruction, or SLEEP instruction
0 = A WDT time-out occurred
bit 2
PD: Power-down Detection Flag bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 1
POR: Power-on Reset Status bit
1 = A Power-on Reset has not 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 = A Brown-out Reset has not occurred
0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs)
Legend:
DS30491D-page 82
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
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5.0
FLASH PROGRAM MEMORY
5.1
Table Reads and Table Writes
The Flash program memory is readable, writable and
erasable during normal operation over the entire VDD
range.
In order to read and write program memory, there are
two operations that allow the processor to move bytes
between the program memory space and the data RAM:
A read from program memory is executed on one byte
at a time. A write to program memory is executed on
blocks of 8 bytes at a time. Program memory is erased
in blocks of 64 bytes at a time. A bulk erase operation
cannot be issued from user code.
• Table Read (TBLRD)
• Table Write (TBLWT)
The program memory space is 16 bits wide, while the
data RAM space is 8-bits wide. Table reads and table
writes move data between these two memory spaces
through an 8-bit register (TABLAT).
Writing or erasing program memory will cease
instruction fetches until the operation is complete. The
program memory cannot be accessed during the write
or erase, therefore, code cannot execute. An internal
programming timer terminates program memory writes
and erases.
Table read operations retrieve data from program
memory and places it into the data RAM space.
Figure 5-1 shows the operation of a table read with
program memory and data RAM.
Table write operations store data from the data memory
space into holding registers in program memory. The
procedure to write the contents of the holding
registers into program memory is detailed in
Section 5.5 “Writing to Flash Program Memory”.
Figure 5-2 shows the operation of a table write with
program memory and data RAM.
A value written to program memory does not need to be
a valid instruction. Executing a program memory
location that forms an invalid instruction results in a
NOP.
Table operations work with byte entities. A table block
containing data, rather than program instructions, is not
required to be word aligned. Therefore, a table block can
start and end at any byte address. If a table write is being
used to write executable code into program memory,
program instructions will need to be word aligned.
FIGURE 5-1:
TABLE READ OPERATION
Instruction: TBLRD*
Program Memory
Table Pointer(1)
TBLPTRU
TBLPTRH
Table Latch (8-bit)
TBLPTRL
TABLAT
Program Memory
(TBLPTR)
Note 1:
Table Pointer points to a byte in program memory.
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FIGURE 5-2:
TABLE WRITE OPERATION
Instruction: TBLWT*
Program Memory
Holding Registers
Table Pointer(1)
TBLPTRU
TBLPTRH
Table Latch (8-bit)
TBLPTRL
TABLAT
Program Memory
(TBLPTR)
Note 1:
5.2
Table Pointer actually points to one of eight holding registers, the address of which is determined by
TBLPTRL. The process for physically writing data to the program memory array is discussed in
Section 5.5 “Writing to Flash Program Memory”.
Control Registers
Several control registers are used in conjunction with
the TBLRD and TBLWT instructions. These include the:
•
•
•
•
EECON1 register
EECON2 register
TABLAT register
TBLPTR registers
5.2.1
EECON1 AND EECON2 REGISTERS
EECON1 is the control register for memory accesses.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the memory write and erase sequences.
Control bit EEPGD determines if the access will be a
program or data EEPROM memory access. When
clear, any subsequent operations will operate on the
data EEPROM memory. When set, any subsequent
operations will operate on the program memory.
Control bit CFGS determines if the access will be to the
configuration/calibration registers or to program
memory/data EEPROM memory. When set, subsequent operations will operate on configuration registers
regardless of EEPGD (see Section 24.0 “Special
Features of the CPU”). When clear, memory selection
access is determined by EEPGD.
DS30491D-page 84
The FREE bit, when set, will allow a program memory
erase operation. When the FREE bit is set, the erase
operation is initiated on the next WR command. When
FREE is clear, only writes are enabled.
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set when a write operation is interrupted by a MCLR
Reset or a WDT Time-out Reset during normal operation. In these situations, the user can check the
WRERR bit and rewrite the location. It is necessary to
reload the data and address registers (EEDATA and
EEADR) due to Reset values of zero.
The WR control bit initiates write operations. The bit
cannot be cleared, only set in software; it is cleared in
hardware at the completion of the write operation. The
inability to clear the WR bit in software prevents the
accidental or premature termination of a write
operation.
Note:
Interrupt flag bit, EEIF in the PIR2 register,
is set when the write is complete. It must
be cleared in software.
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REGISTER 5-1:
EECON1 REGISTER (ADDRESS FA6h)
R/W-x
R/W-x
U-0
R/W-0
R/W-x
R/W-0
R/S-0
R/S-0
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
RD
bit 7
bit 0
bit 7
EEPGD: Flash Program or Data EEPROM Memory Select bit
1 = Access Flash program memory
0 = Access data EEPROM memory
bit 6
CFGS: Flash Program/Data EEPROM or Configuration Select bit
1 = Access configuration registers
0 = Access Flash program or data EEPROM memory
bit 5
Unimplemented: Read as ‘0’
bit 4
FREE: Flash Row Erase Enable bit
1 = Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation)
0 = Perform write only
bit 3
WRERR: Flash Program/Data EEPROM Error Flag bit
1 = A write operation is prematurely terminated
(any Reset during self-timed programming in normal operation)
0 = The write operation completed
Note:
When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows
tracing of the error condition.
bit 2
WREN: Flash Program/Data EEPROM Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the EEPROM
bit 1
WR: Write Control bit
1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write
cycle. (The operation is self-timed and the bit is cleared by hardware once write is
complete. The WR bit can only be set (not cleared) in software.)
0 = Write cycle to the EEPROM is complete
bit 0
RD: Read Control bit
1 = Initiates an EEPROM read. (Read takes one cycle. RD is cleared in hardware. The RD bit
can only be set (not cleared) in software. RD bit cannot be set when EEPGD = 1.)
0 = Does not initiate an EEPROM read
Legend:
R = Readable bit
U = Unimplemented bit, read as ‘0’
W = Writable bit
S = Settable bit
- n = Value after erase
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
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5.2.2
TABLAT – TABLE LATCH REGISTER
5.2.4
The Table Latch (TABLAT) is an 8-bit register mapped
into the SFR space. The Table Latch is used to hold 8bit data during data transfers between program
memory and data RAM.
5.2.3
TBLPTR – TABLE POINTER
REGISTER
The Table Pointer (TBLPTR) addresses a byte within
the program memory. The TBLPTR is comprised of
three SFR registers: Table Pointer Upper Byte, Table
Pointer High Byte and Table Pointer Low Byte
(TBLPTRU:TBLPTRH:TBLPTRL). These three registers join to form a 22-bit wide pointer. The low-order
21 bits allow the device to address up to 2 Mbytes of
program memory space. The 22nd bit allows access to
the device ID, the user ID and the configuration bits.
The Table Pointer, TBLPTR, is used by the TBLRD and
TBLWT instructions. These instructions can update the
TBLPTR in one of four ways based on the table operation. These operations are shown in Table 5-1. These
operations on the TBLPTR only affect the low-order
21 bits.
TABLE 5-1:
TABLE POINTER BOUNDARIES
TBLPTR is used in reads, writes and erases of the
Flash program memory.
When a TBLRD is executed, all 22 bits of the table
pointer determine which byte is read from program
memory into TABLAT.
When a TBLWT is executed, the three LSbs of the Table
Pointer (TBLPTR) determine which of the eight
program memory holding registers is written to. When
the timed write to program memory (long write) begins,
the 19 MSbs of the Table Pointer (TBLPTR) will
determine which program memory block of 8 bytes is
written to. For more detail, see Section 5.5 “Writing to
Flash Program Memory”.
When an erase of program memory is executed, the
16 MSbs of the Table Pointer (TBLPTR) point to
the 64-byte block that will be erased. The Least
Significant bits (TBLPTR) are ignored.
Figure 5-3 describes the relevant boundaries of
TBLPTR based on Flash program memory operations.
TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
Example
Operation on Table Pointer
TBLRD*
TBLWT*
TBLPTR is not modified
TBLRD*+
TBLWT*+
TBLPTR is incremented after the read/write
TBLRD*TBLWT*-
TBLPTR is decremented after the read/write
TBLRD+*
TBLWT+*
TBLPTR is incremented before the read/write
FIGURE 5-3:
21
TABLE POINTER BOUNDARIES BASED ON OPERATION
TBLPTRU
16
15
TBLPTRH
8
7
TBLPTRL
0
ERASE – TBLPTR
WRITE – TBLPTR
READ – TBLPTR
DS30491D-page 86
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5.3
Reading the Flash Program
Memory
TBLPTR points to a byte address in program space.
Executing TBLRD places the byte pointed to into
TABLAT. In addition, TBLPTR can be modified
automatically for the next table read operation.
The TBLRD instruction is used to retrieve data from
program memory and places it into data RAM. Table
reads from program memory are performed one byte at
a time.
FIGURE 5-4:
The internal program memory is typically organized by
words. The Least Significant bit of the address selects
between the high and low bytes of the word. Figure 5-4
shows the interface between the internal program
memory and the TABLAT.
READS FROM FLASH PROGRAM MEMORY
Program Memory
(Even Byte Address)
(Odd Byte Address)
TBLPTR = xxxxx0
TBLPTR = xxxxx1
Instruction Register
(IR)
EXAMPLE 5-1:
FETCH
TBLRD
TABLAT
Read Register
READING A FLASH PROGRAM MEMORY WORD
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
upper(CODE_ADDR)
TBLPTRU
high(CODE_ADDR)
TBLPTRH
low(CODE_ADDR_LOW)
TBLPTRL
; Load TBLPTR with the base
; address of the word
READ_WORD
TBLRD*+
MOVF
MOVWF
TBLRD*+
MOVF
MOVWF
TABLAT, W
LSB
TABLAT, W
MSB
2003-2013 Microchip Technology Inc.
; read into TABLAT and increment
; get data
; read into TABLAT and increment
; get data
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5.4
Erasing Flash Program Memory
5.4.1
The minimum erase block is 32 words or 64 bytes. Only
through the use of an external programmer or through
ICSP control can larger blocks of program memory be
bulk erased. Word erase in the Flash array is not
supported.
The sequence of events for erasing a block of internal
program memory location is:
1.
When initiating an erase sequence from the microcontroller itself, a block of 64 bytes of program memory
is erased. The Most Significant 16 bits of the
TBLPTR point to the block being erased.
TBLPTR are ignored.
2.
The EECON1 register commands the erase operation.
The EEPGD bit must be set to point to the Flash
program memory. The WREN bit must be set to enable
write operations. The FREE bit is set to select an erase
operation.
3.
4.
5.
6.
For protection, the write initiate sequence for EECON2
must be used.
7.
A long write is necessary for erasing the internal Flash.
Instruction execution is halted while in a long write
cycle. The long write will be terminated by the internal
programming timer.
EXAMPLE 5-2:
FLASH PROGRAM MEMORY
ERASE SEQUENCE
8.
9.
Load table pointer with address of row being
erased.
Set the EECON1 register for the erase
operation:
• set EEPGD bit to point to program memory;
• clear the CFGS bit to access program memory;
• set WREN bit to enable writes;
• set FREE bit to enable the erase.
Disable interrupts.
Write 55h to EECON2.
Write 0AAh to EECON2.
Set the WR bit. This will begin the row erase
cycle.
The CPU will stall for duration of the erase
(about 2 ms using internal timer).
Execute a NOP.
Re-enable interrupts.
ERASING A FLASH PROGRAM MEMORY ROW
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
upper(CODE_ADDR)
TBLPTRU
high(CODE_ADDR)
TBLPTRH
low(CODE_ADDR)
TBLPTRL
; load TBLPTR with the base
; address of the memory block
BSF
BCF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
BSF
EECON1,
EECON1,
EECON1,
EECON1,
INTCON,
55h
EECON2
0AAh
EECON2
EECON1,
;
;
;
;
;
ERASE_ROW
Required
Sequence
DS30491D-page 88
EEPGD
CFGS
WREN
FREE
GIE
point to Flash program memory
access Flash program memory
enable write to memory
enable Row Erase operation
disable interrupts
; write 55h
WR
INTCON, GIE
; write 0AAh
; start erase (CPU stall)
; re-enable interrupts
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5.5
Writing to Flash Program Memory
The minimum programming block is 4 words or 8 bytes.
Word or byte programming is not supported.
Table writes are used internally to load the holding
registers needed to program the Flash memory. There
are eight holding registers used by the table writes for
programming.
Since the Table Latch (TABLAT) is only a single byte,
the TBLWT instruction has to be executed 8 times for
each programming operation. All of the table write
operations will essentially be short writes because only
FIGURE 5-5:
the holding registers are written. At the end of updating
eight registers, the EECON1 register must be written
to, to start the programming operation with a long write.
The long write is necessary for programming the internal Flash. Instruction execution is halted while in a long
write cycle. The long write will be terminated by the
internal programming timer.
The EEPROM on-chip timer controls the write time.
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.
TABLE WRITES TO FLASH PROGRAM MEMORY
TABLAT
Write Register
8
8
TBLPTR = xxxxx0
TBLPTR = xxxxx1
Holding Register
8
TBLPTR = xxxxx2
Holding Register
Holding Register
8
TBLPTR = xxxxx7
Holding Register
Program Memory
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5.5.1
FLASH PROGRAM MEMORY WRITE
SEQUENCE
8.
9.
10.
11.
12.
The sequence of events for programming an internal
program memory location should be:
1.
2.
3.
4.
5.
6.
7.
Read 64 bytes into RAM.
Update data values in RAM as necessary.
Load table pointer with address being erased.
Do the row erase procedure.
Load table pointer with address of first byte
being written.
Write the first 8 bytes into the holding registers
with auto-increment.
Set the EECON1 register for the write operation:
• set EEPGD bit to point to program memory;
• clear the CFGS bit to access program memory;
• set WREN to enable byte writes.
EXAMPLE 5-3:
13.
14.
15.
16.
Disable interrupts.
Write 55h to EECON2.
Write 0AAh to EECON2.
Set the WR bit. This will begin the write cycle.
The CPU will stall for duration of the write (about
5 ms using internal timer).
Execute a NOP.
Re-enable interrupts.
Repeat steps 6-14 seven times to write 64 bytes.
Verify the memory (table read).
This procedure will require about 40 ms to update one
row of 64 bytes of memory. An example of the required
code is given in Example 5-3.
Note:
Before setting the WR bit, the Table
Pointer address needs to be within the
intended address range of the eight bytes
in the holding register.
WRITING TO FLASH PROGRAM MEMORY
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
D’64
COUNTER
high(BUFFER_ADDR)
FSR0H
low(BUFFER_ADDR)
FSR0L
upper(CODE_ADDR)
TBLPTRU
high(CODE_ADDR)
TBLPTRH
low(CODE_ADDR)
TBLPTRL
TBLRD*+
MOVF
MOVWF
DECFSZ
BRA
TABLAT, W
POSTINC0
COUNTER
READ_BLOCK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
high(DATA_ADDR)
FSR0H
low(DATA_ADDR)
FSR0L
low(NEW_DATA)
POSTINC0
high(NEW_DATA)
INDF0
; number of bytes in erase block
; point to buffer
; Load TBLPTR with the base
; address of the memory block
READ_BLOCK
;
;
;
;
;
read into TABLAT, and inc
get data
store data
done?
repeat
MODIFY_WORD
DS30491D-page 90
; point to buffer
; update buffer word
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EXAMPLE 5-3:
WRITING TO FLASH PROGRAM MEMORY (CONTINUED)
ERASE_BLOCK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BCF
BSF
BSF
BCF
MOVLW
MOVWF
Required
MOVLW
Sequence
MOVWF
BSF
NOP
BSF
TBLRD*WRITE_BUFFER_BACK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
PROGRAM_LOOP
MOVLW
MOVWF
WRITE_WORD_TO_HREGS
MOVFW
MOVWF
TBLWT+*
upper(CODE_ADDR)
TBLPTRU
high(CODE_ADDR)
TBLPTRH
low(CODE_ADDR)
TBLPTRL
EECON1, EEPGD
EECON1, CFGS
EECON1, WREN
EECON1, FREE
INTCON, GIE
55h
EECON2
0AAh
EECON2
EECON1, WR
; load TBLPTR with the base
; address of the memory block
INTCON, GIE
; re-enable interrupts
; dummy read decrement
8
COUNTER_HI
high(BUFFER_ADDR)
FSR0H
low(BUFFER_ADDR)
FSR0L
; number of write buffer groups of 8 bytes
;
;
;
;
;
point to Flash program memory
access Flash program memory
enable write to memory
enable Row Erase operation
disable interrupts
; write 55H
; write AAH
; start erase (CPU stall)
; point to buffer
8
COUNTER
; number of bytes in holding register
POSTINC0, W
TABLAT
;
;
;
;
;
get low byte of buffer data
present data to table latch
write data, perform a short write
to internal TBLWT holding register.
loop until buffers are full
;
;
;
;
point to Flash program memory
access Flash program memory
enable write to memory
disable interrupts
DECFSZ
BRA
COUNTER
WRITE_WORD_TO_HREGS
BSF
BCF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
BSF
DECFSZ
BRA
BCF
EECON1,
EECON1,
EECON1,
INTCON,
55h
EECON2
0AAh
EECON2
EECON1,
PROGRAM_MEMORY
Required
Sequence
EEPGD
CFGS
WREN
GIE
; write 55h
WR
INTCON, GIE
COUNTER_HI
PROGRAM_LOOP
EECON1, WREN
2003-2013 Microchip Technology Inc.
; write 0AAh
; start program (CPU stall)
; re-enable interrupts
; loop until done
; disable write to memory
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5.5.2
WRITE VERIFY
5.5.4
Depending on the application, good programming
practice may dictate that the value written to the memory should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
5.5.3
UNEXPECTED TERMINATION OF
WRITE OPERATION
TABLE 5-2:
Name
TBLPTRU
To protect against spurious writes to Flash program
memory, the write initiate sequence must also be
followed. See Section 24.0 “Special Features of the
CPU” for more detail.
5.6
If a write is terminated by an unplanned event, such as
loss of power or an unexpected Reset, the memory
location just programmed should be verified and reprogrammed if needed. The WRERR bit is set when a
write operation is interrupted by a MCLR Reset or a
WDT Time-out Reset during normal operation. In these
situations, users can check the WRERR bit and rewrite
the location.
PROTECTION AGAINST SPURIOUS
WRITES
Flash Program Operation During
Code Protection
See Section 24.0 “Special Features of the CPU” for
details on code protection of Flash program memory.
REGISTERS ASSOCIATED WITH PROGRAM FLASH MEMORY
Bit 7
Bit 6
Bit 5
—
—
bit 21
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Program Memory Table Pointer Upper Byte
(TBLPTR)
Value on:
POR, BOR
Value on
all other
Resets
--00 0000
--00 0000
TBPLTRH
Program Memory Table Pointer High Byte (TBLPTR)
0000 0000
0000 0000
TBLPTRL
Program Memory Table Pointer High Byte (TBLPTR)
0000 0000
0000 0000
TABLAT
Program Memory Table Latch
0000 0000
0000 0000
INTCON
GIE/GIEH PEIE/GIEL TMR0IE
0000 0000
EECON2
EEPROM Control Register 2 (not a physical register)
EECON1
INTE
RBIE
TMR0IF
INTF
RBIF
0000 0000
—
—
xx-0 x000
uu-0 u000
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
RD
IPR2
—
CMIP
—
EEIP
BCLIP
LVDIP
TMR3IP
CCP2IP
-1-1 1111
-1-1 1111
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
CCP2IF
-0-0 0000
-0-0 0000
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE
CCP2IE
-0-0 0000
-0-0 0000
PIE2
Legend:
x = unknown, u = unchanged, r = reserved, – = unimplemented, read as ‘0’.
Shaded cells are not used during Flash/EEPROM access.
DS30491D-page 92
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6.0
Note:
EXTERNAL MEMORY
INTERFACE
The external memory interface is not
implemented on PIC18F6X8X (64/68-pin)
devices.
The external memory interface is a feature of the
PIC18F8X8X devices that allows the controller to
access external memory devices (such as Flash,
EPROM, SRAM, etc.) as program memory.
The physical implementation of the interface uses
27 pins. These pins are reserved for external address/
data bus functions; they are multiplexed with I/O port
pins on four ports. Three I/O ports are multiplexed with
the address/data bus, while the fourth port is multiplexed with the bus control signals. The I/O port functions are enabled when the EBDIS bit in the MEMCON
register is set (see Register 6-1). A list of the
multiplexed pins and their functions is provided in
Table 6-1.
As implemented in the PIC18F8X8X devices, the
interface operates in a similar manner to the external
memory interface introduced on PIC18C601/801
microcontrollers. The most notable difference is that
the interface on PIC18F8X8X devices only operates in
16-bit modes. The 8-bit mode is not supported.
6.1
Program Memory Modes and the
External Memory Interface
As previously noted, PIC18F8X8X controllers are
capable of operating in any one of four program memory modes using combinations of on-chip and external
program memory. The functions of the multiplexed port
pins depend on the program memory mode selected as
well as the setting of the EBDIS bit.
In Microprocessor Mode, the external bus is always
active and the port pins have only the external bus
function.
In Microcontroller Mode, the bus is not active and the
pins have their port functions only. Writes to the
MEMCOM register are not permitted.
In Microprocessor with Boot Block or Extended
Microcontroller Mode, the external program memory
bus shares I/O port functions on the pins. When the
device is fetching or doing table read/table write
operations on the external program memory space, the
pins will have the external bus function. If the device is
fetching and accessing internal program memory
locations only, the EBDIS control bit will change the
pins from external memory to I/O port functions. When
EBDIS = 0, the pins function as the external bus. When
EBDIS = 1, the pins function as I/O ports.
For a more complete discussion of the operating modes
that use the external memory interface, refer to
Section 4.1.1 “PIC18F8X8X Program Memory
Modes”.
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REGISTER 6-1:
MEMCON REGISTER
R/W-0
U-0
R/W-0
R/W-0
U-0
U-0
R/W-0
R/W-0
EBDIS(1)
—
WAIT1
WAIT0
—
—
WM1
WM0
bit 7
bit 7
bit 0
EBDIS: External Bus Disable bit(1)
1 = External system bus disabled, all external bus drivers are mapped as I/O ports
0 = External system bus enabled and I/O ports are disabled
Note 1: This bit is ignored when device is accessing external memory either to fetch an
instruction or perform TBLRD/TBLWT.
bit 6
Unimplemented: Read as ‘0’
bit 5-4
WAIT: Table Reads and Writes Bus Cycle Wait Count bits
11 = Table reads and writes will wait 0 TCY
10 = Table reads and writes will wait 1 TCY
01 = Table reads and writes will wait 2 TCY
00 = Table reads and writes will wait 3 TCY
bit 3-2
Unimplemented: Read as ‘0’
bit 1-0
WM: TBLWT Operation with 16-bit Bus bits
1x = Word Write mode: LSB and MSB word output, WRH active when MSB written
01 = Byte Select mode: TABLAT data copied on both MS and LS Byte, WRH and (UB or LB)
will activate
00 = Byte Write mode: TABLAT data copied on both MS and LS Byte, WRH or WRL will activate
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
Note:
DS30491D-page 94
x = Bit is unknown
The MEMCON register is held in Reset in Microcontroller mode.
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If the device fetches or accesses external memory
while EBDIS = 1, the pins will switch to external bus. If
the EBDIS bit is set by a program executing from external memory, the action of setting the bit will be delayed
until the program branches into the internal memory. At
that time, the pins will change from external bus to I/O
ports.
TABLE 6-1:
Name
When the device is executing out of internal memory
(with EBDIS = 0) in Microprocessor with Boot Block
mode or Extended Microcontroller mode, the control signals will be in inactive. They will go to a state where the
AD, A are tri-state; the OE, WRH, WRL,
UB and LB signals are ‘1’; and ALE and BA0 are ‘0’.
PIC18F8X8X EXTERNAL BUS – I/O PORT FUNCTIONS
Port
Bit
Function
RD0/AD0
PORTD
bit 0 Input/Output or System Bus Address bit 0 or Data bit 0
RD1/AD1
PORTD
bit 1 Input/Output or System Bus Address bit 1 or Data bit 1
RD2/AD2
PORTD
bit 2 Input/Output or System Bus Address bit 2 or Data bit 2
RD3/AD3
PORTD
bit 3 Input/Output or System Bus Address bit 3 or Data bit 3
RD4/AD4
PORTD
bit 4 Input/Output or System Bus Address bit 4 or Data bit 4
RD5/AD5
PORTD
bit 5 Input/Output or System Bus Address bit 5 or Data bit 5
RD6/AD6
PORTD
bit 6 Input/Output or System Bus Address bit 6 or Data bit 6
RD7/AD7
PORTD
bit 7 Input/Output or System Bus Address bit 7 or Data bit 7
RE0/AD8
PORTE
bit 0 Input/Output or System Bus Address bit 8 or Data bit 8
RE1/AD9
PORTE
bit 1 Input/Output or System Bus Address bit 9 or Data bit 9
RE2/AD10
PORTE
bit 2 Input/Output or System Bus Address bit 10 or Data bit 10
RE3/AD11
PORTE
bit 3 Input/Output or System Bus Address bit 11 or Data bit 11
RE4/AD12
PORTE
bit 4 Input/Output or System Bus Address bit 12 or Data bit 12
RE5/AD13
PORTE
bit 5 Input/Output or System Bus Address bit 13 or Data bit 13
RE6/AD14
PORTE
bit 6 Input/Output or System Bus Address bit 14 or Data bit 14
RE7/AD15
PORTE
bit 7 Input/Output or System Bus Address bit 15 or Data bit 15
RH0/A16
PORTH
bit 0 Input/Output or System Bus Address bit 16
RH1/A17
PORTH
bit 1 Input/Output or System Bus Address bit 17
RH2/A18
PORTH
bit 2 Input/Output or System Bus Address bit 18
RH3/A19
PORTH
bit 3 Input/Output or System Bus Address bit 19
RJ0/ALE
PORTJ
bit 0 Input/Output or System Bus Address Latch Enable (ALE) Control pin
RJ1/OE
PORTJ
bit 1 Input/Output or System Bus Output Enable (OE) Control pin
RJ2/WRL
PORTJ
bit 2 Input/Output or System Bus Write Low (WRL) Control pin
RJ3/WRH
PORTJ
bit 3 Input/Output or System Bus Write High (WRH) Control pin
RJ4/BA0
PORTJ
bit 4 Input/Output or System Bus Byte Address bit 0
RJ5/CE
PORTJ
bit 5 Input/Output or Chip Enable
RJ6/LB
PORTJ
bit 6 Input/Output or System Bus Lower Byte Enable (LB) Control pin
RJ7/UB
PORTJ
bit 7 Input/Output or System Bus Upper Byte Enable (UB) Control pin
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PIC18F6585/8585/6680/8680
6.2
16-bit Mode
The external memory interface implemented in
PIC18F8X8X devices operates only in 16-bit mode.
The mode selection is not software configurable but is
programmed via the configuration bits.
The WM bits in the MEMCON register determine
three types of connections in 16-bit mode. They are
referred to as:
• 16-bit Byte Write
• 16-bit Word Write
• 16-bit Byte Select
These three different configurations allow the designer
maximum flexibility in using 8-bit and 16-bit memory
devices.
FIGURE 6-1:
For all 16-bit modes, the Address Latch Enable (ALE)
pin indicates that the Address bits (A) are available on the external memory interface bus. Following
the address latch, the Output Enable signal (OE ) will
enable both bytes of program memory at once to form
a 16-bit instruction word.
In Byte Select mode, JEDEC standard Flash memories
will require BA0 for the byte address line, and one I/O
line to select between Byte and Word mode. The other
16-bit modes do not need BA0. JEDEC standard static
RAM memories will use the UB or LB signals for byte
selection.
6.2.1
16-BIT BYTE WRITE MODE
Figure 6-1 shows an example of 16-bit Byte Write
mode for PIC18F8X8X devices.
16-BIT BYTE WRITE MODE EXAMPLE
D
PIC18F8X8X
AD
(MSB)
373
A
D
(LSB)
A
A
D
D
D
CE
AD
373
OE
CE
WR(1)
OE
WR(1)
ALE
A
CE
OE
WRH
WRL
Address Bus
Data Bus
Control Lines
Note 1: This signal only applies to table writes. See Section 5.1 “Table Reads and Table Writes”.
DS30491D-page 96
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PIC18F6585/8585/6680/8680
6.2.2
16-BIT WORD WRITE MODE
Figure 6-2 shows an example of 16-bit Word Write
mode for PIC18F8X8X devices.
FIGURE 6-2:
16-BIT WORD WRITE MODE EXAMPLE
PIC18F8X8X
AD
373
A
A
JEDEC Word
EPROM Memory
D
D
CE
AD
OE
WR(1)
373
ALE
A
CE
OE
WRH
Address Bus
Data Bus
Control Lines
Note 1: This signal only applies to table writes. See Section 5.1 “Table Reads and Table Writes”.
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PIC18F6585/8585/6680/8680
6.2.3
16-BIT BYTE SELECT MODE
Figure 6-3 shows an example of 16-bit Byte Select
mode for PIC18F8X8X devices.
FIGURE 6-3:
16-BIT BYTE SELECT MODE EXAMPLE
PIC18F8X8X
AD
373
A
AD
373
ALE
A
OE
A
A
OE
WRH
WR(1)
WRL
BA0
A0
CE
CE
LB
LB
UB
UB
JEDEC Word
SRAM Memory
D
D
Address Bus
Data Bus
Control Lines
Note 1: This signal only applies to table writes. See Section 5.1 “Table Reads and Table Writes”.
DS30491D-page 98
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PIC18F6585/8585/6680/8680
6.2.4
16-BIT MODE TIMING
Figure 6-4 shows the 16-bit mode external bus timing
for PIC18F8X8X devices.
FIGURE 6-4:
EXTERNAL PROGRAM MEMORY BUS TIMING (16-BIT MODE)
Apparent Q
Actual Q
Q1
Q1
Q2
Q2
A
Q3
Q3
Q4
Q4
0h
3AABh
AD
Q1
Q1
Q2
Q2
Q3
Q3
Q4
Q4
Q4
Q1
Q4
Q2
Q4
Q3
Q4
Q4
Ch
0E55h
CF33h
9256h
BA0
ALE
OE
WRH
‘1’
‘1’
WRL
‘1’
‘1’
1 TCY Wait
Opcode Fetch
Table Read
MOVLW 55h
from 007556h
of 92h
from 199E67h
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NOTES:
DS30491D-page 100
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PIC18F6585/8585/6680/8680
7.0
DATA EEPROM MEMORY
7.1
EEADRH:EEADR
The data EEPROM is readable and writable during normal operation over the entire VDD range. The data
memory is not directly mapped in the register file
space. Instead, it is indirectly addressed through the
Special Function Registers (SFR).
The address register pair, EEADRH:EEADR, can
address up to a maximum of 1024 bytes of data
EEPROM.
There are five SFRs used to read and write the
program and data EEPROM memory. These registers
are:
EECON1 is the control register for EEPROM memory
accesses.
•
•
•
•
•
EECON1
EECON2
EEDATA
EEADR
EEADRH
The EEPROM data memory allows byte read and write.
When interfacing to the data memory block, EEDATA
holds the 8-bit data for read/write and EEADR holds the
address of the EEPROM location being accessed.
These devices have 1024 bytes of data EEPROM with
an address range from 0h to 3FFh.
The EEPROM data memory is rated for high erase/
write cycles. 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
time will vary with voltage and temperature as well as
from chip to chip. Please refer to parameter D122
(Electrical Characteristics, Section 27.0 “Electrical
Characteristics”) for exact limits.
2003-2013 Microchip Technology Inc.
7.2
EECON1 and EECON2 Registers
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the EEPROM write sequence.
Control bits RD and WR initiate read and write operations, respectively. These bits cannot be cleared, only
set in software. They are cleared in hardware at the
completion of the read or write operation. The inability
to clear the WR bit in software prevents the accidental
or premature termination of a write operation.
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set when a write operation is interrupted by a MCLR
Reset or a WDT Time-out Reset during normal operation. In these situations, the user can check the
WRERR bit and rewrite the location. It is necessary to
reload the data and address registers (EEDATA and
EEADR) due to the Reset condition forcing the
contents of the registers to zero.
Note:
Interrupt flag bit, EEIF in the PIR2 register,
is set when write is complete. It must be
cleared in software.
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PIC18F6585/8585/6680/8680
REGISTER 7-1:
EECON1 REGISTER (ADDRESS FA6h)
R/W-x
R/W-x
U-0
R/W-0
R/W-x
R/W-0
R/S-0
R/S-0
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
RD
bit 7
bit 0
bit 7
EEPGD: Flash Program or Data EEPROM Memory Select bit
1 = Access Flash program memory
0 = Access data EEPROM memory
bit 6
CFGS: Flash Program/Data EE or Configuration Select bit
1 = Access configuration or calibration registers
0 = Access Flash program or data EEPROM memory
bit 5
Unimplemented: Read as ‘0’
bit 4
FREE: Flash Row Erase Enable bit
1 = Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation)
0 = Perform write only
bit 3
WRERR: Flash Program/Data EE Error Flag bit
1 = A write operation is prematurely terminated (any MCLR or any WDT Reset during self-timed
programming in normal operation)
0 = The write operation completed
Note:
When a WRERR occurs, the EEPGD or FREE bits are not cleared. This allows
tracing of the error condition.
bit 2
WREN: Flash Program/Data EE Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the EEPROM
bit 1
WR: Write Control bit
1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write cycle.
(The operation is self-timed and the bit is cleared by hardware once write is complete. The
WR bit can only be set (not cleared) in software.)
0 = Write cycle to the EEPROM is complete
bit 0
RD: Read Control bit
1 = Initiates an EEPROM read. (Read takes one cycle. RD is cleared in hardware. The RD bit
can only be set (not cleared) in software. RD bit cannot be set when EEPGD = 1.)
0 = Does not initiate an EEPROM read
Legend:
R = Readable bit
DS30491D-page 102
U = Unimplemented bit, read as ‘0’
W = Writable bit
S = Settable bit
- n = Value after erase
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
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PIC18F6585/8585/6680/8680
7.3
Reading the Data EEPROM
Memory
(EECON1) and then set control bit, RD
(EECON1). The data is available for the very next
instruction cycle; therefore, the EEDATA register can
be read by the next instruction. EEDATA will hold this
value until another read operation or until it is written to
by the user (during a write operation).
To read a data memory location, the user must write the
address to the EEADR register, clear the EEPGD control bit (EECON1), clear the CFGS control bit
EXAMPLE 7-1:
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BCF
BSF
MOVF
7.4
DATA EEPROM READ
DATA_EE_ADR_HI
EEADRH
DATA_EE_ADDR_LOW
EEADR
EECON1, EEPGD
EECON1, CFGS
EECON1, RD
EEDATA, W
;
;
;
;
;
;
;
;
Data Memory Address to read
Point to DATA memory
Access program Flash or Data EEPROM memory
EEPROM Read
W = EEDATA
Writing to the Data EEPROM
Memory
cution (i.e., runaway programs). The WREN bit should
be kept clear at all times except when updating the
EEPROM. The WREN bit is not cleared by hardware.
To write an EEPROM data location, the address must
first be written to the EEADRH:EEADR register pair
and the data written to the EEDATA register. Then the
sequence in Example 7-2 must be followed to initiate
the write cycle.
After a write sequence has been initiated, EECON1,
EEADRH:EEADR and EDATA cannot be modified. The
WR bit will be inhibited from being set unless the
WREN bit is set. The WREN bit must be set on a previous instruction. Both WR and WREN cannot be set
with the same instruction.
The write will not initiate if the above sequence is not
exactly followed (write 55h to EECON2, write 0AAh to
EECON2, then set WR bit) for each byte. It is strongly
recommended that interrupts be disabled during this
code segment.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EEPROM Write Complete
Interrupt Flag bit (EEIF) is set. The user may either
enable this interrupt or poll this bit. EEIF must be
cleared by software.
Additionally, the WREN bit in EECON1 must be set to
enable writes. This mechanism prevents accidental
writes to data EEPROM due to unexpected code exe-
EXAMPLE 7-2:
Required
Sequence
DATA EEPROM WRITE
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BCF
BSF
DATA_EE_ADDR_HI
EEADRH
DATA_EE_ADDR_LOW
EEADR
DATA_EE_DATA
EEDATA
EECON1, EEPGD
EECON1, CFGS
EECON1, WREN
;
;
;
;
;
;
;
;
;
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
INTCON, GIE
55h
EECON2
0AAh
EECON2
EECON1, WR
INTCON, GIE
;
;
;
;
;
;
;
.
.
.
BCF
Data Memory Address to read
Data Memory Value to write
Point to DATA memory
Access program Flash or Data EEPROM memory
Enable writes
Disable interrupts
Write 55h
Write 0AAh
Set WR bit to begin write
Enable interrupts
; user code execution
EECON1, WREN
2003-2013 Microchip Technology Inc.
; Disable writes on write complete (EEIF set)
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7.5
Write Verify
7.7
Depending on the application, good programming
practice may dictate that the value written to the memory should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
7.6
Protection Against Spurious Write
There are conditions when the device 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, the WREN bit is cleared.
Also, the Power-up Timer (72 ms duration) prevents
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during brown-out,
power glitch, or software malfunction.
Operation During Code-Protect
Data EEPROM memory has its own code-protect
mechanism. External read and write operations are
disabled if either of these mechanisms are enabled.
The microcontroller itself can both read and write to the
internal data EEPROM regardless of the state of the
code-protect configuration bit. Refer to Section 24.0
“Special Features of the CPU” for additional
information.
7.8
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 (e.g., program variables or other data that are updated often). Frequently
changing values will typically be updated more often
than specification D124. If this is not the case, an array
refresh must be performed. For this reason, variables
that change infrequently (such as constants, IDs,
calibration, etc.) should be stored in Flash program
memory.
A simple data EEPROM refresh routine is shown in
Example 7-3.
Note:
EXAMPLE 7-3:
DATA EEPROM REFRESH ROUTINE
CLRF
CLRF
BCF
BCF
BCF
BSF
EEADRH
EEADR
EECON1,
EECON1,
INTCON,
EECON1,
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BTFSC
BRA
INCFSZ
BRA
EECON1, RD
55h
EECON2
0AAh
EECON2
EECON1, WR
EECON1, WR
$-2
EEADR, F
Loop
INCFS2
BRA
BCF
BSF
EEADRH, F
Loop
EECON1, WREN
INTCON, GIE
CFGS
EEPGD
GIE
WREN
Loop
DS30491D-page 104
If data EEPROM is only used to store constants and/or data that changes rarely, an
array refresh is likely not required. See
specification D124.
;
;
;
;
;
;
;
;
;
;
;
;
;
;
Start at address 0
Set for memory
Set for Data EEPROM
Disable interrupts
Enable writes
Loop to refresh array
Read current address
Write 55h
Write 0AAh
Set WR bit to begin write
Wait for write to complete
; Increment address
; Not zero, do it again
;
;
; Disable writes
; Enable interrupts
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PIC18F6585/8585/6680/8680
TABLE 7-1:
REGISTERS ASSOCIATED WITH DATA EEPROM MEMORY
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
INTCON
GIE/
GIEH
PEIE/
GIEL
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x 0000 000u
—
—
—
—
—
—
EEADRH
EE Addr High
---- --00 ---- --00
EEADR
EEPROM Address Register
0000 0000 0000 0000
EEDATA
EEPROM Data Register
0000 0000 0000 0000
EECON2 EEPROM Control Register 2 (not a physical register)
EECON1 EEPGD
CFGS
—
FREE
WRERR WREN
—
WR
RD
—
xx-0 x000 uu-0 u000
IPR2
—
CMIP
—
EEIP
BCLIP
LVDIP
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IP CCP2IP -1-1 1111 ---1 1111
TMR3IF CCP2IF -0-0 0000 ---0 0000
PIE2
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE CCP2IE -0-0 0000 ---0 0000
Legend: x = unknown, u = unchanged, r = reserved, – = unimplemented, read as ‘0’.
Shaded cells are not used during Flash/EEPROM access.
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NOTES:
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PIC18F6585/8585/6680/8680
8.0
8.1
8 x 8 HARDWARE MULTIPLIER
8.2
Introduction
An 8 x 8 hardware multiplier is included in the ALU of
the PIC18F6585/8585/6680/8680 devices. By making
the multiply a hardware operation, it completes in a single instruction cycle. This is an unsigned multiply that
gives a 16-bit result. The result is stored in the 16-bit
product register pair (PRODH:PRODL). The multiplier
does not affect any flags in the ALUSTA register.
Example 8-2 shows the sequence to do an 8 x 8 signed
multiply. To account for the sign bits of the arguments,
each argument’s Most Significant bit (MSb) is tested
and the appropriate subtractions are done.
EXAMPLE 8-1:
Making the 8 x 8 multiplier execute in a single cycle
gives the following advantages:
MOVF
MULWF
• Higher computational throughput
• Reduces code size requirements for multiply
algorithms
The performance increase allows the device to be used
in applications previously reserved for Digital Signal
Processors.
ARG1, W
ARG2
;
; ARG1 * ARG2 ->
; PRODH:PRODL
8 x 8 SIGNED MULTIPLY
ROUTINE
MOVF
MULWF
ARG1, W
ARG2
BTFSC
SUBWF
ARG2, SB
PRODH
MOVF
BTFSC
SUBWF
ARG2, W
ARG1, SB
PRODH
;
;
;
;
;
;
;
;
;
;
ARG1 * ARG2 ->
PRODH:PRODL
Test Sign Bit
PRODH = PRODH
- ARG1
Test Sign Bit
PRODH = PRODH
- ARG2
PERFORMANCE COMPARISON
Routine
8 x 8 unsigned
8 x 8 signed
16 x 16 unsigned
16 x 16 signed
8 x 8 UNSIGNED
MULTIPLY ROUTINE
EXAMPLE 8-2:
Table 8-1 shows a performance comparison between
enhanced devices using the single-cycle hardware
multiply and performing the same function without the
hardware multiply.
TABLE 8-1:
Operation
Example 8-1 shows the sequence to do an 8 x 8
unsigned multiply. Only one instruction is required
when one argument of the multiply is already loaded in
the WREG register.
Program
Memory
(Words)
Cycles
(Max)
Without hardware multiply
13
Hardware multiply
1
Without hardware multiply
33
Multiply Method
Time
@ 40 MHz
@ 10 MHz
@ 4 MHz
69
6.9 s
27.6 s
69 s
1
100 ns
400 ns
1 s
91
9.1 s
36.4 s
91 s
Hardware multiply
6
6
600 ns
2.4 s
6 s
Without hardware multiply
21
242
24.2 s
96.8 s
242 s
Hardware multiply
24
24
2.4 s
9.6 s
24 s
Without hardware multiply
52
254
25.4 s
102.6 s
254 s
Hardware multiply
36
36
3.6 s
14.4 s
36 s
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
Example 8-3 shows the sequence to do a 16 x 16
unsigned multiply. Equation 8-1 shows the algorithm
that is used. The 32-bit result is stored in four registers,
RES3:RES0.
EQUATION 8-1:
RES3:RES0
=
=
EXAMPLE 8-3:
16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
ARG1H:ARG1L ARG2H:ARG2L
(ARG1H ARG2H 216) +
(ARG1H ARG2L 28) +
(ARG1L ARG2H 28) +
(ARG1L ARG2L)
EQUATION 8-2:
RES3:RES0
= ARG1H:ARG1L ARG2H:ARG2L
= (ARG1H ARG2H 216) +
(ARG1H ARG2L 28) +
(ARG1L ARG2H 28) +
(ARG1L ARG2L) +
(-1 ARG2H ARG1H:ARG1L 216) +
(-1 ARG1H ARG2H:ARG2L 216)
EXAMPLE 8-4:
16 x 16 UNSIGNED
MULTIPLY ROUTINE
MOVF
MULWF
ARG1L, W
ARG2L
MOVFF
MOVFF
PRODH, RES1
PRODL, RES0
MOVF
MULWF
ARG1H, W
ARG2H
MOVFF
MOVFF
PRODH, RES3
PRODL, RES2
MOVF
MULWF
ARG1L, W
ARG2H
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1
PRODH, W
RES2
WREG
RES3
MOVF
MULWF
ARG1H, W
ARG2L
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1
PRODH, W
RES2
WREG
RES3
; ARG1L * ARG2L ->
; PRODH:PRODL
;
;
16 x 16 SIGNED
MULTIPLICATION
ALGORITHM
16 x 16 SIGNED
MULTIPLY ROUTINE
MOVF
MULWF
ARG1L, W
ARG2L
MOVFF
MOVFF
PRODH, RES1
PRODL, RES0
MOVF
MULWF
ARG1H, W
ARG2H
MOVFF
MOVFF
PRODH, RES3
PRODL, RES2
MOVF
MULWF
ARG1L, W
ARG2H
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1
PRODH, W
RES2
WREG
RES3
MOVF
MULWF
ARG1H, W
ARG2L
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1
PRODH, W
RES2
WREG
RES3
BTFSS
BRA
MOVF
SUBWF
MOVF
SUBWFB
ARG2H, 7
SIGN_ARG1
ARG1L, W
RES2
ARG1H, W
RES3
; ARG2H:ARG2L neg?
; no, check ARG1
;
;
;
ARG1H, 7
CONT_CODE
ARG2L, W
RES2
ARG2H, W
RES3
; ARG1H:ARG1L neg?
; no, done
;
;
;
;
;
; ARG1H * ARG2H ->
; PRODH:PRODL
;
;
ARG1L * ARG2H ->
PRODH:PRODL
Add cross
products
ARG1H * ARG2L ->
PRODH:PRODL
Add cross
products
Example 8-4 shows the sequence to do a 16 x 16
signed multiply. Equation 8-2 shows the algorithm
used. The 32-bit result is stored in four registers,
RES3:RES0. To account for the sign bits of the arguments, each argument pairs’ Most Significant bit (MSb)
is tested and the appropriate subtractions are done.
DS30491D-page 108
;
;
;
;
;
;
;
;
ARG1L * ARG2H ->
PRODH:PRODL
Add cross
products
;
;
;
;
;
;
;
;
;
;
;
; ARG1H * ARG2H ->
; PRODH:PRODL
;
;
;
;
;
;
;
;
;
;
;
;
; ARG1L * ARG2L ->
; PRODH:PRODL
;
;
;
;
;
;
;
;
;
;
;
ARG1H * ARG2L ->
PRODH:PRODL
Add cross
products
;
;
SIGN_ARG1
BTFSS
BRA
MOVF
SUBWF
MOVF
SUBWFB
;
CONT_CODE
:
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
9.0
INTERRUPTS
The PIC18F6585/8585/6680/8680 devices have multiple interrupt sources and an interrupt priority feature
that allows each interrupt source to be assigned a high
or a low priority level. The high priority interrupt vector
is at 000008h while the low priority interrupt vector is at
000018h. High priority interrupt events will override any
low priority interrupts that may be in progress.
There are thirteen registers which are used to control
interrupt operation. They are:
•
•
•
•
•
•
•
RCON
INTCON
INTCON2
INTCON3
PIR1, PIR2, PIR3
PIE1, PIE2, PIE3
IPR1, IPR2, IPR3
It is recommended that the Microchip header files
supplied with MPLAB® IDE be used for the symbolic bit
names in these registers. This allows the assembler/
compiler to automatically take care of the placement of
these bits within the specified register.
Each interrupt source (except INT0) has three bits to
control its operation. The functions of these bits are:
• Flag bit to indicate that an interrupt event
occurred
• Enable bit that allows program execution to
branch to the interrupt vector address when the
flag bit is set
• Priority bit to select high priority or low priority
When the IPEN bit is cleared (default state), the
interrupt priority feature is disabled and interrupts are
compatible with PIC® mid-range devices. In Compatibility mode, the interrupt priority bits for each source
have no effect. INTCON is the PEIE bit which
enables/disables all peripheral interrupt sources.
INTCON is the GIE bit which enables/disables all
interrupt sources. All interrupts branch to address
000008h in Compatibility mode.
When an interrupt is responded to, the global interrupt
enable bit is cleared to disable further interrupts. If the
IPEN bit is cleared, this is the GIE bit. If interrupt priority
levels are used, this will be either the GIEH or GIEL bit.
High priority interrupt sources can interrupt a low
priority interrupt.
The return address is pushed onto the stack and the
PC is loaded with the interrupt vector address
(000008h or 000018h). Once in the Interrupt Service
Routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. The interrupt
flag bits must be cleared in software before re-enabling
interrupts to avoid recursive interrupts.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine and sets the GIE bit (GIEH or GIEL
if priority levels are used) which re-enables interrupts.
For external interrupt events, such as the INT pins or
the PORTB input change interrupt, the interrupt latency
will be three to four instruction cycles. The exact
latency is the same for one- or two-cycle instructions.
Individual interrupt flag bits are set regardless of the
status of their corresponding enable bit or the GIE bit.
The interrupt priority feature is enabled by setting the
IPEN bit (RCON). When interrupt priority is
enabled, there are two bits which enable interrupts
globally. Setting the GIEH bit (INTCON) enables all
interrupts that have the priority bit set. Setting the GIEL
bit (INTCON) enables all interrupts that have the
priority bit cleared. When the interrupt flag, enable bit
and appropriate global interrupt enable bit are set, the
interrupt will vector immediately to address 000008h or
000018h depending on the priority level. Individual
interrupts can be disabled through their corresponding
enable bits.
2003-2013 Microchip Technology Inc.
DS30491D-page 109
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PIC18F6585/8585/6680/8680
FIGURE 9-1:
INTERRUPT LOGIC
TMR0IF
TMR0IE
TMR0IP
RBIF
RBIE
RBIP
INT0IF
INT0IE
Wake-up if in Sleep Mode
Interrupt to CPU
Vector to Location
0008h
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
Peripheral Interrupt Flag bit
Peripheral Interrupt Enable bit
Peripheral Interrupt Priority bit
GIEH/GIE
TMR1IF
TMR1IE
TMR1IP
IPE
IPEN
XXXXIF
XXXXIE
XXXXIP
GIEL/PEIE
IPEN
Additional Peripheral Interrupts
High Priority Interrupt Generation
Low Priority Interrupt Generation
Peripheral Interrupt Flag bit
Peripheral Interrupt Enable bit
Peripheral Interrupt Priority bit
TMR1IF
TMR1IE
TMR1IP
RBIF
RBIE
RBIP
XXXXIF
XXXXIE
XXXXIP
Additional Peripheral Interrupts
DS30491D-page 110
Interrupt to CPU
Vector to Location
0018h
TMR0IF
TMR0IE
TMR0IP
GIEL/PEIE
GIE/GEIH
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
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PIC18F6585/8585/6680/8680
9.1
INTCON Registers
Note:
The INTCON registers are readable and writable
registers which contain various enable, priority and flag
bits.
REGISTER 9-1:
Interrupt flag bits are set when an interrupt
condition occurs regardless of the state of
its corresponding enable bit or the global
enable bit. User software should ensure
the appropriate interrupt flag bits are clear
prior to enabling an interrupt. This feature
allows for software polling.
INTCON REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-x
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
bit 7
bit 0
bit 7
GIE/GIEH: Global Interrupt Enable bit
When IPEN (RCON) = 0:
1 = Enables all unmasked interrupts
0 = Disables all interrupts
When IPEN (RCON) = 1:
1 = Enables all high priority interrupts
0 = Disables all interrupts
bit 6
PEIE/GIEL: Peripheral Interrupt Enable bit
When IPEN (RCON) = 0:
1 = Enables all unmasked peripheral interrupts
0 = Disables all peripheral interrupts
When IPEN (RCON) = 1:
1 = Enables all low priority peripheral interrupts
0 = Disables all low priority peripheral interrupts
bit 5
TMR0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 overflow interrupt
0 = Disables the TMR0 overflow interrupt
bit 4
INT0IE: INT0 External Interrupt Enable bit
1 = Enables the INT0 external interrupt
0 = Disables the INT0 external interrupt
bit 3
RBIE: RB Port Change Interrupt Enable bit
1 = Enables the RB port change interrupt
0 = Disables the RB port change interrupt
bit 2
TMR0IF: TMR0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed (must be cleared in software)
0 = TMR0 register did not overflow
bit 1
INT0IF: INT0 External Interrupt Flag bit
1 = The INT0 external interrupt occurred (must be cleared in software)
0 = The INT0 external interrupt did not occur
bit 0
RBIF: RB Port Change Interrupt Flag bit
1 = At least one of the RB7:RB4 pins changed state (must be cleared in software)
0 = None of the RB7:RB4 pins have changed state
Note:
A mismatch condition will continue to set this bit. Reading PORTB will end the
mismatch condition and allow the bit to be cleared.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
DS30491D-page 111
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PIC18F6585/8585/6680/8680
REGISTER 9-2:
INTCON2 REGISTER
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
RBPU
INTEDG0
INTEDG1
INTEDG2
INTEDG3
TMR0IP
INT3IP
RBIP
bit 7
bit 0
bit 7
RBPU: PORTB Pull-up Enable bit
1 = All PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual port latch values
bit 6
INTEDG0: External Interrupt 0 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 5
INTEDG1: External Interrupt 1 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 4
INTEDG2: External Interrupt 2 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 3
INTEDG3: External Interrupt 3 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 2
TMR0IP: TMR0 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1
INT3IP: INT3 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0
RBIP: RB Port Change Interrupt Priority bit
1 = High priority
0 = Low priority
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
Note:
DS30491D-page 112
x = Bit is unknown
Interrupt flag bits are set when an interrupt condition occurs regardless of the state
of its corresponding enable bit or the global enable bit. User software should ensure
the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature
allows for software polling.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
REGISTER 9-3:
INTCON3 REGISTER
R/W-1
R/W-1
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
INT2IP
INT1IP
INT3IE
INT2IE
INT1IE
INT3IF
INT2IF
INT1IF
bit 7
bit 0
bit 7
INT2IP: INT2 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6
INT1IP: INT1 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
INT3IE: INT3 External Interrupt Enable bit
1 = Enables the INT3 external interrupt
0 = Disables the INT3 external interrupt
bit 4
INT2IE: INT2 External Interrupt Enable bit
1 = Enables the INT2 external interrupt
0 = Disables the INT2 external interrupt
bit 3
INT1IE: INT1 External Interrupt Enable bit
1 = Enables the INT1 external interrupt
0 = Disables the INT1 external interrupt
bit 2
INT3IF: INT3 External Interrupt Flag bit
1 = The INT3 external interrupt occurred (must be cleared in software)
0 = The INT3 external interrupt did not occur
bit 1
INT2IF: INT2 External Interrupt Flag bit
1 = The INT2 external interrupt occurred (must be cleared in software)
0 = The INT2 external interrupt did not occur
bit 0
INT1IF: INT1 External Interrupt Flag bit
1 = The INT1 external interrupt occurred (must be cleared in software)
0 = The INT1 external interrupt did not occur
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
Note:
x = Bit is unknown
Interrupt flag bits are set when an interrupt condition occurs regardless of the state
of its corresponding enable bit or the global enable bit. User software should ensure
the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature
allows for software polling.
2003-2013 Microchip Technology Inc.
DS30491D-page 113
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PIC18F6585/8585/6680/8680
9.2
PIR Registers
Note 1: 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).
The PIR registers contain the individual flag bits for the
peripheral interrupts. Due to the number of peripheral
interrupt sources, there are three Peripheral Interrupt
Flag registers (PIR1, PIR2 and PIR3).
REGISTER 9-4:
2: User software should ensure the appropriate interrupt flag bits are cleared prior to
enabling an interrupt, and after servicing
that interrupt.
PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
R/W-0
R/W-0
R-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
bit 7
bit 0
bit 7
PSPIF: Parallel Slave Port Read/Write Interrupt Flag bit(1)
1 = A read or a write operation has taken place (must be cleared in software)
0 = No read or write has occurred
bit 6
ADIF: A/D Converter Interrupt Flag bit
1 = An A/D conversion completed (must be cleared in software)
0 = The A/D conversion is not complete
bit 5
RCIF: USART Receive Interrupt Flag bit
1 = The USART receive buffer, RCREG, is full (cleared when RCREG is read)
0 = The USART receive buffer is empty
bit 4
TXIF: USART Transmit Interrupt Flag bit
1 = The USART transmit buffer, TXREG, is empty (cleared when TXREG is written)
0 = The USART transmit buffer is full
bit 3
SSPIF: Master Synchronous Serial Port Interrupt Flag bit
1 = The transmission/reception is complete (must be cleared in software)
0 = Waiting to transmit/receive
bit 2
CCP1IF: Enhanced CCP1 Interrupt Flag bit
Capture mode:
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare mode:
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM mode:
Unused in this mode.
bit 1
TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1 = TMR2 to PR2 match occurred (must be cleared in software)
0 = No TMR2 to PR2 match occurred
bit 0
TMR1IF: TMR1 Overflow Interrupt Flag bit
1 = TMR1 register overflowed (must be cleared in software)
0 = TMR1 register did not overflow
Note 1: Available in Microcontroller mode only.
Legend:
DS30491D-page 114
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
REGISTER 9-5:
PIR2: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 2
U-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
CCP2IF
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
CMIF: Comparator Interrupt Flag bit
1 = The comparator input has changed (must be cleared in software)
0 = The comparator input has not changed
bit 5
Unimplemented: Read as ‘0’
bit 4
EEIF: Data EEPROM/Flash Write Operation Interrupt Flag bit
1 = The write operation is complete (must be cleared in software)
0 = The write operation is not complete, or has not been started
bit 3
BCLIF: Bus Collision Interrupt Flag bit
1 = A bus collision occurred while the SSP module (configured in I2C Master mode)
was transmitting (must be cleared in software)
0 = No bus collision occurred
bit 2
LVDIF: Low-Voltage Detect Interrupt Flag bit
1 = A low-voltage condition occurred (must be cleared in software)
0 = The device voltage is above the Low-Voltage Detect trip point
bit 1
TMR3IF: TMR3 Overflow Interrupt Flag bit
1 = TMR3 register overflowed (must be cleared in software)
0 = TMR3 register did not overflow
bit 0
CCP2IF: CCP2 Interrupt Flag bit
Capture mode:
1 = A TMR1 or TMR3 register capture occurred (must be cleared in software)
0 = No TMR1 or TMR3 register capture occurred
Compare mode:
1 = A TMR1 or TMR3 register compare match occurred (must be cleared in software)
0 = No TMR1 or TMR3 register compare match occurred
PWM mode:
Unused in this mode.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
DS30491D-page 115
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PIC18F6585/8585/6680/8680
REGISTER 9-6:
PIR3: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 3
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
IRXIF
WAKIF
ERRIF
TXB2IF/
TXBnIF
TXB1IF(1)
TXB0IF(1)
RXB1IF/
RXBnIF
RXB0IF/
FIFOWMIF
bit 7
bit 0
bit 7
IRXIF: CAN Invalid Received Message Interrupt Flag bit
1 = An invalid message has occurred on the CAN bus
0 = No invalid message on CAN bus
bit 6
WAKIF: CAN bus Activity Wake-up Interrupt Flag bit
1 = Activity on CAN bus has occurred
0 = No activity on CAN bus
bit 5
ERRIF: CAN bus Error Interrupt Flag bit
1 = An error has occurred in the CAN module (multiple sources)
0 = No CAN module errors
bit 4
When CAN is in Mode 0:
TXB2IF: CAN Transmit Buffer 2 Interrupt Flag bit
1 = Transmit Buffer 2 has completed transmission of a message and may be reloaded
0 = Transmit Buffer 2 has not completed transmission of a message
When CAN is in Mode 1 or 2:
TXBnIF: Any Transmit Buffer Interrupt Flag bit
1 = One or more transmit buffers has completed transmission of a message and may be
reloaded (TXBIE or BIE0 must be non-zero)
0 = No message was transmitted
bit 3
TXB1IF: CAN Transmit Buffer 1 Interrupt Flag bit(1)
1 = Transmit Buffer 1 has completed transmission of a message and may be reloaded
0 = Transmit Buffer 1 has not completed transmission of a message
bit 2
TXB0IF: CAN Transmit Buffer 0 Interrupt Flag bit(1)
1 = Transmit Buffer 0 has completed transmission of a message and may be reloaded
0 = Transmit Buffer 0 has not completed transmission of a message
bit 1
When CAN is in Mode 0:
RXB1IF: CAN Receive Buffer 1 Interrupt Flag bit
1 = Receive Buffer 1 has received a new message
0 = Receive Buffer 1 has not received a new message
When CAN is in Mode 1 or 2:
RXBnIF: CAN Receive Buffer Interrupt Flag bit
1 = One or more receive buffers has received a new message
0 = No receive buffer has received a new message
bit 0
When CAN is in Mode 0:
RXB0IF: CAN Receive Buffer 0 Interrupt Flag bit(1)
1 = Receive Buffer 0 has received a new message
0 = Receive Buffer 0 has not received a new message
When CAN is in Mode 1:
Unimplemented: Read as ‘0’
When CAN is in Mode 2:
FIFOWMIF: FIFO Watermark Interrupt Flag bit
1 = FIFO high watermark is reached
0 = FIFO high watermark is not reached
Legend:
DS30491D-page 116
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
9.3
PIE Registers
The PIE registers contain the individual enable bits for
the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are three Peripheral
Interrupt Enable registers (PIE1, PIE2 and PIE3).
When the IPEN bit (RCON) is ‘0’, the PEIE bit must
be set to enable any of these peripheral interrupts.
REGISTER 9-7:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
bit 7
bit 0
bit 7
PSPIE: Parallel Slave Port Read/Write Interrupt Enable bit(1)
1 = Enables the PSP read/write interrupt
0 = Disables the PSP read/write interrupt
bit 6
ADIE: A/D Converter Interrupt Enable bit
1 = Enables the A/D interrupt
0 = Disables the A/D interrupt
bit 5
RCIE: USART Receive Interrupt Enable bit
1 = Enables the USART receive interrupt
0 = Disables the USART receive interrupt
bit 4
TXIE: USART Transmit Interrupt Enable bit
1 = Enables the USART transmit interrupt
0 = Disables the USART transmit interrupt
bit 3
SSPIE: Master Synchronous Serial Port Interrupt Enable bit
1 = Enables the MSSP interrupt
0 = Disables the MSSP interrupt
bit 2
CCP1IE: Enhanced CCP1 Interrupt Enable bit
1 = Enables the CCP1 interrupt
0 = Disables the CCP1 interrupt
bit 1
TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1 = Enables the TMR2 to PR2 match interrupt
0 = Disables the TMR2 to PR2 match interrupt
bit 0
TMR1IE: TMR1 Overflow Interrupt Enable bit
1 = Enables the TMR1 overflow interrupt
0 = Disables the TMR1 overflow interrupt
Note 1: Available in Microcontroller mode 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
DS30491D-page 117
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PIC18F6585/8585/6680/8680
REGISTER 9-8:
PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
U-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE
CCP2IE
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
CMIE: Comparator Interrupt Enable bit
1 = Enables the comparator interrupt
0 = Disables the comparator interrupt
bit 5
Unimplemented: Read as ‘0’
bit 4
EEIE: Data EEPROM/Flash Write Operation Interrupt Enable bit
1 = Enables the write operation interrupt
0 = Disables the write operation interrupt
bit 3
BCLIE: Bus Collision Interrupt Enable bit
1 = Enables the bus collision interrupt
0 = Disables the bus collision interrupt
bit 2
LVDIE: Low-Voltage Detect Interrupt Enable bit
1 = Enables the Low-Voltage Detect interrupt
0 = Disables the Low-Voltage Detect interrupt
bit 1
TMR3IE: TMR3 Overflow Interrupt Enable bit
1 = Enables the TMR3 overflow interrupt
0 = Disables the TMR3 overflow interrupt
bit 0
CCP2IE: CCP2 Interrupt Enable bit
1 = Enables the CCP2 interrupt
0 = Disables the CCP2 interrupt
Legend:
DS30491D-page 118
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
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PIC18F6585/8585/6680/8680
REGISTER 9-9:
PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3
R/W-0
R/W-0
R/W-0
R/W-0
IRXIE
WAKIE
ERRIE
TXB2IE/
TXBnIE
R/W-0
R/W-0
TXB1IE(1) TXB0IE(1)
R/W-0
R/W-0
RXB1IE/
RXBnIE
RXB0IE/
FIFOWMIE
bit 7
bit 0
bit 7
IRXIE: CAN Invalid Received Message Interrupt Enable bit
1 = Enable invalid message received interrupt
0 = Disable invalid message received interrupt
bit 6
WAKIE: CAN bus Activity Wake-up Interrupt Enable bit
1 = Enable bus activity wake-up interrupt
0 = Disable bus activity wake-up interrupt
bit 5
ERRIE: CAN bus Error Interrupt Enable bit
1 = Enable CAN bus error interrupt
0 = Disable CAN bus error interrupt
bit 4
When CAN is in Mode 0:
TXB2IE: CAN Transmit Buffer 2 Interrupt Enable bit
1 = Enable Transmit Buffer 2 interrupt
0 = Disable Transmit Buffer 2 interrupt
When CAN is in Mode 1 or 2:
TXBnIE: CAN Transmit Buffer Interrupts Enable bit
1 = Enable transmit buffer interrupt; individual interrupt is enabled by TXBIE and BIE0
0 = Disable all transmit buffer interrupts
bit 3
TXB1IE: CAN Transmit Buffer 1 Interrupt Enable bit(1)
1 = Enable Transmit Buffer 1 interrupt
0 = Disable Transmit Buffer 1 interrupt
bit 2
TXB0IE: CAN Transmit Buffer 0 Interrupt Enable bit(1)
1 = Enable Transmit Buffer 0 interrupt
0 = Disable Transmit Buffer 0 interrupt
bit 1
When CAN is in Mode 0:
RXB1IE: CAN Receive Buffer 1 Interrupt Enable bit
1 = Enable Receive Buffer 1 interrupt
0 = Disable Receive Buffer 1 interrupt
When CAN is in Mode 1 or 2:
RXBnIE: CAN Receive Buffer Interrupts Enable bit
1 = Enable receive buffer interrupt; individual interrupt is enabled by BIE0
0 = Disable all receive buffer interrupts
bit 0
When CAN is in Mode 0:
RXB0IE: CAN Receive Buffer 0 Interrupt Enable bit
1 = Enable Receive Buffer 0 interrupt
0 = Disable Receive Buffer 0 interrupt
When CAN is in Mode 1:
Unimplemented: Read as ‘0’
When CAN is in Mode 2:
FIFOWMIE: FIFO Watermark Interrupt Enable bit
1 = Enable FIFO watermark interrupt
0 = Disable FIFO watermark interrupt
Note 1: In CAN Mode 1 and 2, this bit is forced to ‘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
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x = Bit is unknown
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9.4
IPR Registers
The IPR registers contain the individual priority bits for
the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are three Peripheral
Interrupt Priority registers (IPR1, IPR2 and IPR3). The
operation of the priority bits requires that the Interrupt
Priority Enable (IPEN) bit be set.
REGISTER 9-10:
IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
bit 7
bit 0
bit 7
PSPIP: Parallel Slave Port Read/Write Interrupt Priority bit(1)
1 = High priority
0 = Low priority
bit 6
ADIP: A/D Converter Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
RCIP: USART Receive Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4
TXIP: USART Transmit Interrupt Priority bit
Note 1: Available in Microcontroller mode only.
1 = High priority
0 = Low priority
bit 3
SSPIP: Master Synchronous Serial Port Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2
CCP1IP: CCP1 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1
TMR2IP: TMR2 to PR2 Match Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0
TMR1IP: TMR1 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
DS30491D-page 120
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
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REGISTER 9-11:
IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
U-0
R/W-1
U-0
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
—
CMIP
—
EEIP
BCLIP
LVDIP
TMR3IP
CCP2IP
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
CMIP: Comparator Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
Unimplemented: Read as ‘0’
bit 4
EEIP: Data EEPROM/Flash Write Operation Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3
BCLIP: Bus Collision Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2
LVDIP: Low-Voltage Detect Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1
TMR3IP: TMR3 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0
CCP2IP: CCP2 Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 9-12:
IPR3: PERIPHERAL INTERRUPT PRIORITY REGISTER 3
R/W-1
R/W-1
R/W-1
R/W-1
IRXIP
WAKIP
ERRIP
TXB2IP/
TXBnIP
R/W-1
R/W-1
TXB1IP(1) TXB0IP(1)
bit 7
R/W-1
R/W-1
RXB1IP/
RXBnIP
RXB0IP/
FIFOWMIP
bit 0
bit 7
IRXIP: CAN Invalid Received Message Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6
WAKIP: CAN bus Activity Wake-up Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
ERRIP: CAN bus Error Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4
When CAN is in Mode 0:
TXB2IP: CAN Transmit Buffer 2 Interrupt Priority bit
1 = High priority
0 = Low priority
When CAN is in Mode 1 or 2:
TXBnIP: CAN Transmit Buffer Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3
TXB1IP: CAN Transmit Buffer 1 Interrupt Priority bit(1)
1 = High priority
0 = Low priority
bit 2
TXB0IP: CAN Transmit Buffer 0 Interrupt Priority bit(1)
1 = High priority
0 = Low priority
bit 1
When CAN is in Mode 0:
RXB1IP: CAN Receive Buffer 1 Interrupt Priority bit
1 = High priority
0 = Low priority
When CAN is in Mode 1 or 2:
RXBnIP: CAN Receive Buffer Interrupts Priority bit
1 = High priority
0 = Low priority
bit 0
When CAN is in Mode 0:
RXB0IP: CAN Receive Buffer 0 Interrupt Priority bit
1 = High priority
0 = Low priority
When CAN is in Mode 1:
Unimplemented: Read as ‘0’
When CAN is in Mode 2:
FIFOWMIP: FIFO Watermark Interrupt Priority bit
1 = High priority
0 = Low priority
Note 1: In CAN Mode 1 and 2, this bit is forced to ‘0’.
Legend:
DS30491D-page 122
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
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9.5
RCON Register
The RCON register contains the IPEN bit which is used
to enable prioritized interrupts. The functions of the
other bits in this register are discussed in more detail in
Section 4.14 “RCON Register”.
REGISTER 9-13:
RCON REGISTER
R/W-0
U-0
U-0
R/W-1
R-1
R-1
R/W-0
R/W-0
IPEN
—
—
RI
TO
PD
POR
BOR
bit 7
bit 0
bit 7
IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (PIC16 Compatibility mode)
bit 6-5
Unimplemented: Read as ‘0’
bit 4
RI: RESET Instruction Flag bit
For details of bit operation, see Register 4-4.
bit 3
TO: Watchdog Time-out Flag bit
For details of bit operation, see Register 4-4.
bit 2
PD: Power-down Detection Flag bit
For details of bit operation, see Register 4-4.
bit 1
POR: Power-on Reset Status bit
For details of bit operation, see Register 4-4.
bit 0
BOR: Brown-out Reset Status bit
For details of bit operation, see Register 4-4.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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9.6
INT0 Interrupt
9.7
External interrupts on the RB0/INT0, RB1/INT1, RB2/
INT2 and RB3/INT3 pins are edge-triggered: either rising if the corresponding INTEDGx bit is set in the
INTCON2 register, or falling if the INTEDGx bit is clear.
When a valid edge appears on the RBx/INTx pin, the
corresponding flag bit, INTxF, is set. This interrupt can
be disabled by clearing the corresponding enable bit,
INTxE. Flag bit, INTxF, must be cleared in software in
the Interrupt Service Routine before re-enabling the
interrupt. All external interrupts (INT0, INT1, INT2 and
INT3) can wake-up the processor from Sleep if bit
INTxIE was set prior to going into Sleep. If the global
interrupt enable bit GIE is set, the processor will branch
to the interrupt vector following wake-up.
The interrupt priority for INT, INT2 and INT3 is determined by the value contained in the interrupt priority
bits: INT1IP (INTCON3), INT2IP (INTCON3)
and INT3IP (INTCON2). There is no priority bit
associated with INT0; it is always a high priority
interrupt source.
TMR0 Interrupt
In 8-bit mode (which is the default), an overflow in the
TMR0 register (0FFh 00h) will set flag bit TMR0IF. In
16-bit mode, an overflow in the TMR0H:TMR0L registers (0FFFFh 0000h) will set flag bit, TMR0IF. The
interrupt can be enabled/disabled by setting/clearing
enable bit, TMR0IE (INTCON). Interrupt priority for
Timer0 is determined by the value contained in the
interrupt priority bit, TMR0IP (INTCON2). See
Section 11.0 “Timer0 Module” for further details on
the Timer0 module.
9.8
PORTB Interrupt-on-Change
An input change on PORTB sets flag bit RBIF
(INTCON). The interrupt can be enabled/disabled
by setting/clearing enable bit, RBIE (INTCON).
Interrupt priority for PORTB interrupt-on-change is
determined by the value contained in the interrupt
priority bit, RBIP (INTCON2).
9.9
Context Saving During Interrupts
During an interrupt, the return PC value is saved on the
stack. Additionally, the WREG, Status and BSR registers
are saved on the fast return stack. If a fast return from
interrupt is not used (See Section 4.3 “Fast Register
Stack”), the user may need to save the WREG, Status
and BSR registers in software. Depending on the user’s
application, other registers may also need to be saved.
Example 9-1 saves and restores the WREG, Status and
BSR registers during an Interrupt Service Routine.
EXAMPLE 9-1:
SAVING STATUS, WREG AND BSR REGISTERS IN RAM
MOVWF
W_TEMP
MOVFF
STATUS, STATUS_TEMP
MOVFF
BSR, BSR_TEMP
;
; USER ISR CODE
;
MOVFF
BSR_TEMP, BSR
MOVF
W_TEMP, W
MOVFF
STATUS_TEMP, STATUS
DS30491D-page 124
; W_TEMP is in virtual bank
; STATUS_TEMP located anywhere
; BSR located anywhere
; Restore BSR
; Restore WREG
; Restore STATUS
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10.0
I/O PORTS
10.1
Depending on the device selected, there are either seven
or nine I/O ports available on PIC18F6X8X/8X8X
devices. Some of their pins are multiplexed with one or
more alternate functions from the other peripheral features on the device. In general, when a peripheral is
enabled, that pin may not be used as a general purpose
I/O pin.
Each port has three registers for its operation. These
registers are:
• TRIS register (data direction register)
• PORT register (reads the levels on the pins of the
device)
• LAT register (output latch)
The Data Latch register (LAT) is useful for read-modifywrite operations on the value that the I/O pins are
driving.
A simplified version of a generic I/O port and its
operation is shown in Figure 10-1.
FIGURE 10-1:
SIMPLIFIED BLOCK
DIAGRAM OF
PORT/LAT/TRIS
OPERATION
RD LAT
D
WR LAT +
WR Port
PORTA is a 7-bit wide, bidirectional port. The corresponding data direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
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).
Reading the PORTA register reads the status of the
pins, whereas writing to it will write to the port latch.
The Data Latch register (LATA) is also memory
mapped. Read-modify-write operations on the LATA
register read and write the latched output value for
PORTA.
The RA4 pin is multiplexed with the Timer0 module
clock input to become the RA4/T0CKI pin. The
RA4/T0CKI pin is a Schmitt Trigger input and an opendrain output. All other RA port pins have TTL input
levels and full CMOS output drivers.
The RA6 pin is only enabled as a general I/O pin in
ECIO and RCIO Oscillator modes.
The other PORTA pins are multiplexed with analog
inputs and the analog VREF+ and VREF- inputs. The
operation of each pin is selected by clearing/setting the
control bits in the ADCON1 register (A/D Control
Register 1).
Note:
TRIS
Q
CK
Data Bus
2003-2013 Microchip Technology Inc.
On a Power-on Reset, RA5 and RA3:RA0
are configured as analog inputs and read
as ‘0’. RA6 and RA4 are configured as
digital inputs.
The TRISA register controls the direction of the RA pins
even when they are being used as analog inputs. The
user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
Data Latch
RD Port
PORTA, TRISA and LATA
Registers
I/O pin
EXAMPLE 10-1:
CLRF
PORTA
CLRF
LATA
MOVLW
MOVWF
MOVLW
0Fh
ADCON1
0CFh
MOVWF
TRISA
INITIALIZING PORTA
;
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTA by
clearing output
data latches
Alternate method
to clear output
data latches
Configure A/D
for digital inputs
Value used to
initialize data
direction
Set RA as inputs
RA as outputs
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FIGURE 10-2:
BLOCK DIAGRAM OF
RA3:RA0 AND RA5 PINS
FIGURE 10-3:
BLOCK DIAGRAM OF
RA4/T0CKI PIN
RD LATA
RD LATA
Data
Bus
D
WR LATA
or
PORTA
Data
Bus
Q
WR LATA
or
PORTA
VDD
CK
Q
P
WR TRISA
N
Q
I/O pin(1)
WR TRISA
CK
Q
CK
Q
N
Data Latch
Data Latch
D
D
VSS
Analog
Input
Mode
Q
TRIS Latch
D
Q
CK
Q
I/O pin(1)
VSS
Schmitt
Trigger
Input
Buffer
TRIS Latch
RD TRISA
RD TRISA
Q
D
TTL
Input
Buffer
Q
D
ENEN
EN
RD PORTA
RD PORTA
TMR0 Clock Input
To A/D Converter and LVD Modules
Note 1:
Note 1:
I/O pins have protection diodes to VDD and VSS.
FIGURE 10-4:
I/O pins have protection diodes to VDD and VSS.
BLOCK DIAGRAM OF RA6 PIN (WHEN ENABLED AS I/O)
ECRA6 or RCRA6 Enable
Data Bus
RD LATA
WR LATA or PORTA
D
Q
CK
Q
VDD
P
Data Latch
WR TRISA
D
Q
CK
Q
N
I/O pin(1)
VSS
TRIS Latch
TTL
Input
Buffer
RD TRISA
ECRA6 or RCRA6 Enable
Q
D
EN
RD PORTA
Note 1:
I/O pins have protection diodes to VDD and VSS.
DS30491D-page 126
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TABLE 10-1:
PORTA FUNCTIONS
Bit#
Buffer
RA0/AN0
Name
bit 0
TTL
Input/output or analog input.
Function
RA1/AN1
bit 1
TTL
Input/output or analog input.
RA2/AN2/VREF-
bit 2
TTL
Input/output or analog input or VREF-.
RA3/AN3/VREF+
bit 3
TTL
Input/output or analog input or VREF+.
RA4/T0CKI
bit 4
RA5/AN4/LVDIN
bit 5
ST/OD Input/output or external clock input for Timer0. Output is open-drain type.
TTL
Input/output or slave select input for synchronous serial port or analog
input, or Low-Voltage Detect input.
OSC2/CLKO/RA6
bit 6
TTL
OSC2 or clock output, or I/O pin.
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 10-2:
Name
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Bit 7
Value on
all other
Resets
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
RA6
RA5
RA4
RA3
RA2
RA1
RA0
-x0x 0000 -u0u 0000
PORTA
—
LATA
—
LATA Data Output Register
TRISA
—
PORTA Data Direction Register
ADCON1
—
—
VCFG1 VCFG0 PCFG3
-xxx xxxx -uuu uuuu
-111 1111 -111 1111
PCFG2
PCFG1
PCFG0
--00 0000 --00 0000
Legend: x = unknown, u = unchanged, – = unimplemented locations read as ‘0’.
Shaded cells are not used by PORTA.
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10.2
PORTB, TRISB and LATB
Registers
PORTB is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB
pin an input (i.e., put the corresponding output driver in
a 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).
The Data Latch register (LATB) is also memory mapped.
Read-modify-write operations on the LATB register read
and write the latched output value for PORTB.
EXAMPLE 10-2:
CLRF
PORTB
CLRF
LATB
MOVLW
0CFh
MOVWF
TRISB
INITIALIZING PORTB
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTB by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RB as inputs
RB as outputs
RB as inputs
A mismatch condition will continue to set flag bit, RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
For PIC18FXX85 devices, RB3 can be configured by the
configuration bit, CCP2MX, as the alternate peripheral
pin for the CCP2 module. This is only available when the
device is configured in Microprocessor, Microprocessor
with Boot Block, or Extended Microcontroller Operating
modes.
The RB5 pin is used as the LVP programming pin.
When the LVP configuration bit is programmed, this pin
loses the I/O function and becomes a programming test
function.
Note:
When LVP is enabled, the weak pull-up on
RB5 is disabled.
FIGURE 10-5:
BLOCK DIAGRAM OF
RB7:RB4 PINS
VDD
RBPU(2)
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is
performed by clearing bit RBPU (INTCON2). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
Note:
On a Power-on Reset, these pins are
configured as digital inputs.
Four of the PORTB pins (RB3:RB0) are the external
interrupt pins, INT3 through INT0. In order to use these
pins as external interrupts, the corresponding TRISB
bit must be set to ‘1’.
The other four PORTB pins (RB7:RB4) have an
interrupt-on-change feature. Only pins configured as
inputs can cause this interrupt to occur (i.e., any
RB7:RB4 pin configured as an output is excluded from
the interrupt-on-change comparison). The input pins (of
RB7:RB4) are compared with the old value latched on
the last read of PORTB. The “mismatch” outputs of
RB7:RB4 are OR’ed together to generate the RB port
change interrupt with flag bit, RBIF (INTCON).
This interrupt can wake the device from Sleep. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
b)
Any read or write of PORTB (except with the
MOVFF instruction). This will end the mismatch
condition.
Clear flag bit RBIF.
DS30491D-page 128
Weak
P Pull-up
Data Bus
WR LATB
or PORTB
Data Latch
D
Q
I/O pin(1)
CK
TRIS Latch
D
WR TRISB
Q
TTL
Input
Buffer
CK
ST
Buffer
RD TRISB
RD LATB
Latch
Q
D
RD PORTB
EN
Q1
Set RBIF
Q
D
RD PORTB
From other
RB7:RB4 pins
EN
Q3
RB7:RB5 in Serial Programming Mode
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (INTCON2).
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FIGURE 10-6:
BLOCK DIAGRAM OF RB2:RB0 PINS
VDD
RBPU(2)
Weak
P Pull-up
Data Latch
D
Q
Data Bus
I/O pin(1)
WR Port
CK
TRIS Latch
D
WR TRIS
Q
TTL
Input
Buffer
CK
RD TRIS
Q
D
RD Port
EN
INTx
Schmitt Trigger
Buffer
Note 1:
2:
RD Port
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (OPTION_REG).
FIGURE 10-7:
BLOCK DIAGRAM OF RB3 PIN
VDD
RBPU(2)
CCP2MX
Weak
P Pull-up
CCP Output(3)
1
VDD
P
Enable(3)
CCP Output
0
Data Latch
Data Bus
D
WR LATB or
WR PORTB
I/O pin(1)
Q
N
CK
VSS
TRIS Latch
D
WR TRISB
CK
TTL
Input
Buffer
Q
RD TRISB
RD LATB
Q
D
RD PORTB
EN
RD PORTB
CCP2 or INT3
Schmitt Trigger
Buffer
Note 1:
2:
3:
CCP2MX = 0
I/O pin has diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
For PIC18FXX85 parts, the CCP2 input/output is multiplexed with RB3 if the CCP2MX bit is enabled (= 0) in the Configuration
register and the device is operating in Microprocessor, Microprocessor with Boot Block or Extended Microcontroller mode.
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TABLE 10-3:
PORTB FUNCTIONS
Bit#
Buffer
RB0/INT0
Name
bit 0
TTL/ST(1)
Input/output pin or external interrupt input 0. Internal software
programmable weak pull-up.
RB1/INT1
bit 1
TTL/ST(1)
Input/output pin or external interrupt input 1. Internal software
programmable weak pull-up.
RB2/INT2
bit 2
TTL/ST(1)
Input/output pin or external interrupt input 2. Internal software
programmable weak pull-up.
RB3/INT3/CCP2(3)
bit 3
TTL/ST(4)
Input/output pin or external interrupt input 3. Capture 2 input/
Compare 2 output/PWM output (when CCP2MX configuration bit is
enabled, all PIC18FXX85 operating modes except Microcontroller
mode). Internal software programmable weak pull-up.
RB4/KBI0
bit 4
TTL
Input/output pin (with interrupt-on-change). Internal software
programmable weak pull-up.
RB5/KBI1/PGM
bit 5
TTL/ST(2)
Input/output pin (with interrupt-on-change). Internal software
programmable weak pull-up. Low-voltage ICSP enable pin.
RB6/KBI2/PGC
bit 6
TTL/ST(2)
Input/output pin (with interrupt-on-change). Internal software
programmable weak pull-up. Serial programming clock.
RB7/KBI3/PGD
bit 7
TTL/ST(2)
Input/output pin (with interrupt-on-change). Internal software
programmable weak pull-up. Serial programming data.
Legend:
Note 1:
2:
3:
4:
TTL = TTL input, ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as the external interrupt.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
RC1 is the alternate assignment for CCP2 when CCP2MX is not set (all operating modes except
Microcontroller mode).
This buffer is a Schmitt Trigger input when configured as the CCP2 input.
TABLE 10-4:
Name
PORTB
Function
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
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0
xxxx xxxx
uuuu uuuu
LATB
LATB Data Output Register
xxxx xxxx
uuuu uuuu
TRISB
PORTB Data Direction Register
1111 1111
1111 1111
0000 0000
0000 0000
INTCON
GIE/
GIEH
INTCON2
RBPU
INTCON3
INT2IP
Legend:
PEIE/
GIEL
TMR0IF
INT0IF
INTEDG0 INTEDG1 INTEDG2 INTEDG3 TMR0IP
INT3IP
RBIP
1111 1111
1111 1111
INT2IF
INT1IF
1100 0000
1100 0000
INT1IP
TMR0IE
INT3IE
INT0IE
INT2IE
RBIE
INT1IE
INT3IF
RBIF
x = unknown, u = unchanged. Shaded cells are not used by PORTB.
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10.3
PORTC, TRISC and LATC
Registers
The pin override value is not loaded into the TRIS register. This allows read-modify-write of the TRIS register
without concern due to peripheral overrides.
PORTC is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISC. Setting a
TRISC bit (= 1) will make the corresponding PORTC
pin an input (i.e., put the corresponding output driver in
a 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).
RC1 is normally configured by configuration bit,
CCP2MX, as the default peripheral pin of the CCP2
module (default/erased state, CCP2MX = 1).
EXAMPLE 10-3:
The Data Latch register (LATC) is also memory mapped.
Read-modify-write operations on the LATC register read
and write the latched output value for PORTC.
PORTC is multiplexed with several peripheral functions
(Table 10-5). PORTC pins have Schmitt Trigger input
buffers.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an
output, while other peripherals override the TRIS bit to
make a pin an input. The user should refer to the corresponding peripheral section for the correct TRIS bit
settings.
Note:
CLRF
PORTC
CLRF
LATC
MOVLW
0CFh
MOVWF
TRISC
INITIALIZING PORTC
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTC by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RC as inputs
RC as outputs
RC as inputs
On a Power-on Reset, these pins are
configured as digital inputs.
FIGURE 10-8:
PORTC BLOCK DIAGRAM (PERIPHERAL OUTPUT OVERRIDE)
PORTC/Peripheral Out Select
Peripheral Data Out
VDD
0
P
RD LATC
Data Bus
WR LATC or
WR PORTC
1
D
Q
CK
Q
I/O pin(1)
Data Latch
D
WR TRISC
CK
Q
TRIS Latch
TRIS OVERRIDE
N
Q
VSS
TRIS
Override
Logic
Pin
Override
Peripheral
RC0
Yes
Timer1 Osc for
Timer1/Timer3
RC1
Yes
Timer1 Osc for
Timer1/Timer3,
CCP2 I/O
RC2
Yes
CCP1 I/O
RC3
Yes
SPI/I2C
Master Clock
RD TRISC
Schmitt
Trigger
Peripheral Output
Enable (2)
Q
D
EN
RD PORTC
Peripheral Data In
Note 1: I/O pins have diode protection to VDD and VSS.
2: Peripheral output enable is only active if peripheral select is active.
2003-2013 Microchip Technology Inc.
RC4
Yes
I2C Data Out
RC5
Yes
SPI Data Out
RC6
Yes
USART Async
Xmit, Sync Clock
RC7
Yes
USART Sync
Data Out
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TABLE 10-5:
PORTC FUNCTIONS
Name
Bit#
Buffer Type
RC0/T1OSO/T13CKI
bit 0
ST
Input/output port pin, Timer1 oscillator output or Timer1/Timer3
clock input.
Function
RC1/T1OSI/CCP2(1)
bit 1
ST
Input/output port pin, Timer1 oscillator input or Capture 2 input/
Compare 2 output/PWM output (when CCP2MX configuration bit is
disabled).
RC2/CCP1/P1A
bit 2
ST
Input/output port pin or Capture 1 input/Compare 1 output/
PWM1 output.
RC3/SCK/SCL
bit 3
ST
RC3 can also be the synchronous serial clock for both SPI and I2C
modes.
RC4/SDI/SDA
bit 4
ST
RC4 can also be the SPI data in (SPI mode) or data I/O (I2C mode).
RC5/SDO
bit 5
ST
Input/output port pin or synchronous serial port data output.
RC6/TX/CK
bit 6
ST
Input/output port pin, addressable USART asynchronous transmit or
addressable USART synchronous clock.
RC7/RX/DT
bit 7
ST
Input/output port pin, addressable USART asynchronous receive or
addressable USART synchronous data.
Legend: ST = Schmitt Trigger input
Note 1: RB3 is the alternate assignment for CCP2 when CCP2MX is set.
TABLE 10-6:
Name
PORTC
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx
uuuu uuuu
LATC
LATC Data Output Register
xxxx xxxx
uuuu uuuu
TRISC
PORTC Data Direction Register
1111 1111
1111 1111
Legend: x = unknown, u = unchanged
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10.4
PORTD, TRISD and LATD
Registers
PORTD is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISD. Setting a
TRISD bit (= 1) will make the corresponding PORTD
pin an input (i.e., put the corresponding output driver in
a high-impedance mode). Clearing a TRISD bit (= 0)
will make the corresponding PORTD pin an output (i.e.,
put the contents of the output latch on the selected pin).
FIGURE 10-9:
RD LATD
Data
Bus
WR LATD
or
PORTD
D
Note:
On a Power-on Reset, these pins are
configured as digital inputs.
On PIC18F8X8X devices, PORTD is multiplexed with
the system bus as the external memory interface; I/O
port functions are only available when the system bus
is disabled by setting the EBDIS bit in the MEMCOM
register (MEMCON). When operating as the external memory interface, PORTD is the low-order byte of
the multiplexed address/data bus (AD7:AD0).
Q
I/O pin(1)
CK
Data Latch
The Data Latch register (LATD) is also memory mapped.
Read-modify-write operations on the LATD register read
and write the latched output value for PORTD.
PORTD is an 8-bit port with Schmitt Trigger input
buffers. Each pin is individually configurable as an input
or output.
PORTD BLOCK DIAGRAM
IN I/O PORT MODE
D
WR TRISD
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRISD
Q
D
ENEN
RD PORTD
Note 1:
I/O pins have diode protection to VDD and VSS.
PORTD can also be configured as an 8-bit wide microprocessor port (Parallel Slave Port) by setting control
bit, PSPMODE (TRISE). In this mode, the input
buffers are TTL. See Section 10.10 “Parallel Slave
Port (PSP)” for additional information.
EXAMPLE 10-4:
CLRF
PORTD
CLRF
LATD
MOVLW
0CFh
MOVWF
TRISD
INITIALIZING PORTD
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTD by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RD as inputs
RD as outputs
RD as inputs
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FIGURE 10-10:
PORTD BLOCK DIAGRAM IN SYSTEM BUS MODE (PIC18F8X8X ONLY)
Q
D
EN
EN
RD PORTD
RD LATD
Data Bus
D
Q
Port
Data
WR LATD
or PORTD
CK
0
1
I/O pin(1)
Data Latch
D
WR TRISD
Q
CK
TRIS Latch
TTL
Input
Buffer
RD TRISD
System Bus
Control
Bus Enable
Data/TRIS Out
Drive Bus
Instruction Register
Instruction Read
Note 1: I/O pins have protection diodes to VDD and VSS.
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TABLE 10-7:
PORTD FUNCTIONS
Bit#
Buffer Type
Function
RD0/PSP0/AD0(2)
Name
bit 0
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 0 or address/data bus bit 0.
RD1/PSP1/AD1(2)
bit 1
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 1 or address/data bus bit 1.
(2)
bit 2
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 2 or address/data bus bit 2.
RD3/PSP3/AD3(2)
bit 3
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 3 or address/data bus bit 3.
RD4/PSP4/AD4(2)
bit 4
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 4 or address/data bus bit 4.
RD5/PSP5/AD5(2)
bit 5
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 5 or address/data bus bit 5.
RD6/PSP6/AD6(2)
bit 6
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 6 or address/data bus bit 6.
RD7/PSP7/AD7(2)
bit 7
ST/TTL(1)
Input/output port pin, Parallel Slave Port bit 7 or address/data bus bit 7.
RD2/PSP2/AD2
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in System Bus or Parallel Slave
Port mode.
2: Available in PIC18F8X8X devices only.
TABLE 10-8:
Name
PORTD
SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
RD7
RD6
RD5
RD4
RD3
RD2
RD1
RD0
xxxx xxxx
uuuu uuuu
LATD
LATD Data Output Register
xxxx xxxx
uuuu uuuu
TRISD
PORTD Data Direction Register
1111 1111
1111 1111
PSPCON
IBF
OBF
IBOV
PSPMODE
—
—
—
—
0000 ----
0000 ----
MEMCON
EBDIS
—
WAIT1
WAIT0
—
—
WM1
WM0
0-00 --00
0-00 --00
Legend: x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by PORTD.
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10.5
PORTE, TRISE and LATE
Registers
PORTE is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISE. Setting a
TRISE bit (= 1) will make the corresponding PORTE
pin an input (i.e., put the corresponding output driver in
a high-impedance mode). Clearing a TRISE bit (= 0)
will make the corresponding PORTE pin an output (i.e.,
put the contents of the output latch on the selected pin).
Read-modify-write operations on the LATE register
read and write the latched output value for PORTE.
PORTE is an 8-bit port with Schmitt Trigger input
buffers. Each pin is individually configurable as an input
or output. PORTE is multiplexed with the Enhanced
CCP module (Table 10-9).
On PIC18F8X8X devices, PORTE is also multiplexed
with the system bus as the external memory interface;
the I/O bus is available only when the system bus is
disabled by setting the EBDIS bit in the MEMCON
register (MEMCON). If the device is configured in
Microprocessor or Extended Microcontroller mode, then
the PORTE becomes the high byte of the address/
data bus for the external program memory interface. In
Microcontroller mode, the PORTE pins become the
control inputs for the Parallel Slave Port when bit
PSPMODE (PSPCON) is set. (Refer to
Section 4.1.1 “PIC18F8X8X Program Memory
Modes” for more information on program memory
modes.)
Pin RE7 can be configured as the alternate peripheral
pin for the CCP2 module when the device is operating
in Microcontroller mode. This is done by clearing the
configuration bit, CCP2MX, in configuration register,
CONFIG3H (CONFIG3H).
Note:
For PIC18F8X8X (80-pin) devices operating in other than Microcontroller mode,
PORTE defaults to the system bus on
Power-on Reset.
EXAMPLE 10-5:
CLRF
PORTE
CLRF
LATE
MOVLW
03h
MOVWF
TRISE
INITIALIZING PORTE
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTE by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RE1:RE0 as inputs
RE7:RE2 as outputs
When the Parallel Slave Port is active, three PORTE
pins (RE0/RD/AD8, RE1/WR/AD9 and RE2/CS/AD10)
function as its control inputs. This automatically occurs
when the PSPMODE bit (PSPCON) is set. Users
must also make certain that bits TRISE are set to
configure the pins as digital inputs and the ADCON1
register is configured for digital I/O. The PORTE PSP
control functions are summarized in Table 10-9.
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FIGURE 10-11:
PORTE BLOCK DIAGRAM IN I/O MODE
Peripheral Out Select
Peripheral Data Out
VDD
0
P
RD LATE
1
Data Bus
WR LATE
or WR PORTE
D
Q
CK
Q
I/O pin(1)
Data Latch
WR TRISE
D
Q
CK
Q
N
TRIS OVERRIDE
VSS
TRIS
Override
TRIS Latch
RD TRISE
Schmitt
Trigger
Peripheral Enable
Q
D
EN
RD PORTE
Peripheral Data In
Pin
Override
Peripheral
RE0
Yes
External Bus
RE1
Yes
External Bus
RE2
Yes
External Bus
RE3
Yes
External Bus
RE4
Yes
External Bus
RE5
Yes
External Bus
RE6
Yes
External Bus
RE7
Yes
External Bus
Note 1: I/O pins have diode protection to VDD and VSS.
FIGURE 10-12:
PORTE BLOCK DIAGRAM IN SYSTEM BUS MODE (PIC18F8X8X ONLY)
Q
D
ENEN
RD PORTE
RD LATE
Data Bus
D
Q
Port
Data
WR LATE
or PORTE
CK
0
1
I/O pin(1)
Data Latch
D
WR TRISE
Q
CK
TRIS Latch
TTL
Input
Buffer
RD TRISE
Bus Enable
System Bus Data/TRIS Out
Control
Drive Bus
Instruction Register
Instruction Read
Note 1: I/O pins have protection diodes to VDD and VSS.
2003-2013 Microchip Technology Inc.
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TABLE 10-9:
PORTE FUNCTIONS
Bit#
Buffer Type
RE0/RD/AD8(2)
Name
bit 0
ST/TTL(1)
Input/output port pin, read control for Parallel Slave Port or
address/data bit 8.
For RD (PSP Control mode):
1 = Not a read operation
0 = Read operation, reads PORTD register (if chip selected)
Function
RE1/WR/AD9(2)
bit 1
ST/TTL(1)
Input/output port pin, write control for Parallel Slave Port or
address/data bit 9.
For WR (PSP Control mode):
1 = Not a write operation
0 = Write operation, writes PORTD register (if chip selected)
RE2/CS/AD10(2)
bit 2
ST/TTL(1)
Input/output port pin, chip select control for Parallel Slave Port or
address/data bit 10.
For CS (PSP Control mode):
1 = Device is not selected
0 = Device is selected
RE3/AD11(2)
bit 3
ST/TTL(1)
Input/output port pin or address/data bit 11.
RE4/AD12(2)
bit 4
ST/TTL(1)
Input/output port pin or address/data bit 12.
RE5/AD13/(2)P1C(3)
bit 5
ST/TTL(1)
Input/output port pin, address/data bit 13 or ECCP1 PWM output C.
RE6/AD14/(2)P1B(3)
bit 6
ST/TTL(1)
Input/output port pin, address/data bit 13 or ECCP1 PWM output B.
RE7/CCP2/AD15(2)
bit 7
ST/TTL(1)
Input/output port pin, Capture 2 input/Compare 2 output/PWM output
(PIC18F8X20 devices in Microcontroller mode only) or
address/data bit 15.
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O or CCP mode, and TTL buffers when in System Bus or PSP
Control mode.
2: Available in PIC18F8X8X devices only.
3: On PIC18F8X8X devices, these pins may be moved to RHY or RH6 by changing the ECCPMX
configuration bit.
TABLE 10-10: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
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
TRISE
PORTE Data Direction Control Register
1111 1111
1111 1111
PORTE
Read PORTE pin/Write PORTE Data Latch
xxxx xxxx
uuuu uuuu
LATE
Read PORTE Data Latch/Write PORTE Data Latch
xxxx xxxx
uuuu uuuu
MEMCON
EBDIS
—
WAIT1
WAIT0
—
—
WM1
WM0
0-00 --00
0000 --00
PSPCON
IBF
OBF
IBOV
PSPMODE
—
—
—
—
0000 ----
0000 ----
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTE.
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10.6
PORTF, LATF and TRISF Registers
EXAMPLE 10-6:
PORTF is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISF. Setting a
TRISF bit (= 1) will make the corresponding PORTF pin
an input (i.e., put the corresponding output driver in a
high-impedance mode). Clearing a TRISF bit (= 0) will
make the corresponding PORTF pin an output (i.e., put
the contents of the output latch on the selected pin).
Read-modify-write operations on the LATF register
read and write the latched output value for PORTF.
PORTF is multiplexed with several analog peripheral
functions, including the A/D converter inputs and
comparator inputs, outputs, and voltage reference.
CLRF
PORTF
CLRF
LATF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
07h
CMCON
0Fh
ADCON1
0CFh
MOVWF
TRISF
Note 1: On a Power-on Reset, the RF6:RF0 pins
are configured as inputs and read as ‘0’.
INITIALIZING PORTF
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTF by
clearing output
data latches
Alternate method
to clear output
data latches
Turn off comparators
Set PORTF as digital I/O
Value used to
initialize data
direction
Set RF3:RF0 as inputs
RF5:RF4 as outputs
RF7:RF6 as inputs
2: To configure PORTF as digital I/O, turn off
comparators and set ADCON1 value.
FIGURE 10-13:
PORTF RF1/AN6/C2OUT AND RF2/AN7/C1OUT PINS BLOCK DIAGRAM
Port/Comparator Select
Comparator Data Out
VDD
0
P
RD LATF
Data Bus
WR LATF or
WR PORTF
D
CK
1
Q
I/O pin
Q
Data Latch
D
WR TRISF
CK
N
Q
VSS
Q
TRIS Latch
Analog
Input
Mode
RD TRISF
Schmitt
Trigger
Q
D
EN
RD PORTF
To A/D Converter
Note 1: I/O pins have diode protection to VDD and VSS.
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FIGURE 10-14:
RF6:RF3 AND RF0 PINS
BLOCK DIAGRAM
FIGURE 10-15:
RD LATF
RD LATF
Data
Bus
Data
Bus
D
WR LATF
or
WR PORTF
WR LATF or
WR PORTF
VDD
CK
D
Q
P
I/O pin
CK
D
N
Q
TRIS Latch
Q
Schmitt
Trigger
Input
Buffer
I/O pin
VSS
Analog
Input
Mode
Q
Q
Data Latch
WR TRISF
CK
D
Q
Data Latch
WR TRISF
RF7 PIN BLOCK
DIAGRAM
CK
TRIS Latch
TTL
Input
Buffer
RD TRISF
RD TRISF
ST
Input
Buffer
Q
Q
D
D
ENEN
EN
RD PORTF
RD PORTF
SS Input
To A/D Converter or Comparator Input
Note
1:
I/O pins have diode protection to VDD and VSS.
DS30491D-page 140
Note:
I/O pins have diode protection to VDD and VSS.
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TABLE 10-11: PORTF FUNCTIONS
Bit#
Buffer Type
RF0/AN5
Name
bit 0
ST
Input/output port pin or analog input.
RF1/AN6/C2OUT
bit 1
ST
Input/output port pin, analog input or comparator 2 output.
RF2/AN7/C1OUT
bit 2
ST
Input/output port pin, analog input or comparator 1 output.
RF3/AN8/C2IN+
bit 3
ST
Input/output port pin, analog input or comparator 2 input (+).
RF4/AN9/C2IN-
bit 4
ST
Input/output port pin, analog input or comparator 2 input (-).
RF5/AN10/
C1IN+/CVREF
bit 5
ST
Input/output port pin, analog input, comparator 1 input (+) or
comparator reference output.
RF6/AN11/C1IN-
bit 6
ST
RF7/SS
bit 7
ST/TTL
Function
Input/output port pin, analog input or comparator 1 input (-).
Input/output port pin or slave select pin for synchronous serial port.
Legend: ST = Schmitt Trigger input, TTL = TTL input
TABLE 10-12: SUMMARY OF REGISTERS ASSOCIATED WITH PORTF
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
TRISF
PORTF Data Direction Control Register
1111 1111
1111 1111
PORTF
Read PORTF pin/Write PORTF Data Latch
xxxx xxxx
uuuu uuuu
LATF
Read PORTF Data Latch/Write PORTF Data Latch
0000 0000
uuuu uuuu
ADCON1
—
—
CMCON
C2OUT
CVRCON CVREN
VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0
--00 0000
--00 0000
C1OUT
C2INV
CVROE
CVRR CVRSS
C1INV
CIS
CM2
CM1
CM0
0000 0000
0000 0000
CVR3
CVR2
CVR1
CVR0
0000 0000
0000 0000
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTF.
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10.7
PORTG, TRISG and LATG
Registers
The pin override value is not loaded into the TRIS register. This allows read-modify-write of the TRIS register
without concern due to peripheral overrides.
PORTG is a 6-bit wide port with 5 bidirectional pins and
1 unidirectional pin. The corresponding data direction
register is TRISG. Setting a TRISG bit (= 1) will make
the corresponding PORTG pin an input (i.e., put the
corresponding output driver in a high-impedance
mode). Clearing a TRISG bit (= 0) will make the corresponding PORTG pin an output (i.e., put the contents
of the output latch on the selected pin).
The Data Latch register (LATG) is also memory mapped.
Read-modify-write operations on the LATG register read
and write the latched output value for PORTG.
EXAMPLE 10-7:
CLRF
PORTG
CLRF
LATG
MOVLW 04h
MOVWF TRISG
Pins RG0-RG2 on PORTG are multiplexed with the CAN
peripheral. Refer to Section 23.0 “ECAN Module” for
proper settings of TRISG when CAN is enabled. RG5 is
multiplexed with MCLR/VPP. Refer to Register 24-5 for
more information.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTG pin. Some
peripherals override the TRIS bit to make a pin an output,
while other peripherals override the TRIS bit to make a
pin an input. The user should refer to the corresponding
peripheral section for the correct TRIS bit settings.
Note:
Initialize PORTG by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RG1:RG0 as outputs
RG2 as input
RG4:RG3 as inputs
Note 1: On a Power-on Reset, RG5 is enabled as
a digital input only if Master Clear
functionality is disabled (MCLRE = 0).
2: If the device Master Clear is disabled,
verify that either of the following is done to
ensure proper entry into ICSP mode:
a) disable Low-Voltage Programming
(CONFIG4L = 0); or
b) make certain that RB5/KBI1/PGM is
held low during entry into ICSP.
On a Power-on Reset, these pins are
configured as digital inputs.
FIGURE 10-16:
INITIALIZING PORT
;
;
;
;
;
;
;
;
;
;
;
;
RG0/CANTX1 PIN BLOCK DIAGRAM
OPMODE2:OPMODE0 = 000
TXD
ENDRHI
0
VDD
RD LATG
Data Bus
WR PORTG or
WR LATG
D
Q
CK
Q
1
P
Data Latch
WR TRISG
D
Q
CK
Q
I/O pin
N
TRIS Latch
RD TRISG
VSS
OPMODE2:OPMODE0 = 000
Q
Schmitt
Trigger
D
EN
EN
RD PORTG
Note: I/O pins have diode protection to VDD and VSS.
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FIGURE 10-17:
RG1/CANTX2 PIN BLOCK DIAGRAM
TX1SRC
TXD
0
CANCLK
1
OPMODE2:OPMODE0 = 000
TX2EN
ENDRHI
0
VDD
RD LATG
1
Data Bus
WR PORTG or
WR LATG
D
Q
CK
Q
P
Data Latch
D
Q
CK
Q
I/O pin
N
WR TRISG
TRIS Latch
VSS
OPMODE2:OPMODE0 = 000
RD TRISG
Q
Schmitt
Trigger
D
EN
RD PORTG
Note: I/O pins have diode protection to VDD and VSS.
FIGURE 10-18:
RG2/CANRX PIN BLOCK
DIAGRAM
FIGURE 10-19:
RD LATG
Data Bus
WR LATG
or
WR PORTG
D
WR TRISG
RD LATG
Data Bus
Q
I/O pin
CK
Data Latch
D
RG3 PIN BLOCK
DIAGRAM
D
Q
I/O pin
WR LATG
or
WR PORTG
Q
CK
Data Latch
D
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
WR TRISG
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRISG
RD TRISG
Q
D
Q
ENEN
ENEN
RD PORTG
CANRX
Note: I/O pins have diode protection to VDD and VSS.
2003-2013 Microchip Technology Inc.
D
RD PORTG
Note: I/O pins have diode protection to VDD and VSS.
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FIGURE 10-20:
RG4/P1D PIN BLOCK DIAGRAM
CCP1 P1D Enable
P1D Out
RD LATG
Data Bus
WR LATG
or
WR PORTG
D
CK
Data Latch
D
WR TRISG
1
Q
0
I/O pin
Auto-Shutdown
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRISG
Q
D
EN
EN
RD PORTG
Note: I/O pins have diode protection to VDD and VSS.
FIGURE 10-21:
RG5/MCLR/VPP PIN BLOCK DIAGRAM
MCLRE
Data Bus
RG5/MCLR/VPP
RD TRISA
Schmitt
Trigger
RD LATA
Latch
Q
D
EN
RD PORTA
High-Voltage Detect
HV
Internal MCLR
Filter
Low-Level
MCLR Detect
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TABLE 10-13: PORTG FUNCTIONS
Bit#
Buffer Type
RG0/CANTX1
Name
bit 0
ST
Input/output port pin or CAN bus transmit output.
Function
RG1/CANTX2
bit 1
ST
Input/output port pin, CAN bus complimentary transmit output or CAN
bus bit time clock.
RG2/CANRX
bit 2
ST
Input/output port pin or CAN bus receive.
RG3
bit 3
ST
Input/output port pin.
RG4/P1D
bit 4
ST
Input/output port pin or ECCP1 PWM output D.
RG5/MCLR/VPP
bit 5
ST
Master Clear input or programming voltage input (if MCLR is enabled).
Input only port pin or programming voltage input (if MCLR is
disabled).
Legend: ST = Schmitt Trigger input
TABLE 10-14: SUMMARY OF REGISTERS ASSOCIATED WITH PORTG
Name
Bit 7
Bit 6
Bit 5
PORTG
—
—
RG5(1)
LATG
—
—
—
TRISG
—
—
—
Value on
POR, BOR
Value on
all other
Resets
Read PORTF pin/Write PORTF Data Latch
--0x xxxx
--0u uuuu
LATG Data Output Register
---x xxxx
---u uuuu
Data Direction Control Register for PORTG
---1 1111
---1 1111
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Legend: x = unknown, u = unchanged
Note 1: RG5 is available as an input only when MCLR is disabled.
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10.8
Note:
PORTH, LATH and TRISH
Registers
PORTH is available only on PIC18F8X8X
devices.
FIGURE 10-22:
RD LATH
PORTH is an 8-bit wide, bidirectional I/O port. The corresponding data direction register is TRISH. Setting a
TRISH bit (= 1) will make the corresponding PORTH
pin an input (i.e., put the corresponding output driver in
a high-impedance mode). Clearing a TRISH bit (= 0)
will make the corresponding PORTH pin an output (i.e.,
put the contents of the output latch on the selected pin).
Data
Bus
Read-modify-write operations on the LATH register
read and write the latched output value for PORTH.
WR TRISH
Pins RH7:RH4 are multiplexed with analog inputs
AN15:AN12. Pins RH3:RH0 are multiplexed with the
system bus as the external memory interface; they are
the high-order address bits, A19:A16. By default, pins
RH7:RH4 are enabled as A/D inputs and pins
RH3:RH0 are enabled as the system address bus.
Register ADCON1 configures RH7:RH4 as I/O or A/D
inputs. Register MEMCON configures RH3:RH0 as I/O
or system bus pins.
Pins RH7 and RH6 can be configured as the alternate
peripheral pins for CCP1 PWM output P1B and P1C,
respectively. This is done by clearing the configuration
bit ECCPMX, in configuration register CONFIG3H
(CONFIG3H).
Note 1: On Power-on Reset, PORTH pins
RH7:RH4 default to A/D inputs and read
as ‘0’.
2: On Power-on Reset, PORTH pins
RH3:RH0 default to system bus signals.
EXAMPLE 10-8:
CLRF
CLRF
PORTH
LATH
MOVLW
MOVWF
MOVLW
0Fh
ADCON1
0CFh
MOVWF
TRISH
INITIALIZING PORTH
;
;
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTH by
clearing output
data latches
Alternate method
to clear output
data latches
RH3:RH0 PINS BLOCK
DIAGRAM IN I/O MODE
WR LATH
or
PORTH
D
Q
I/O pin(1)
CK
Data Latch
D
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRISH
Q
D
ENEN
RD PORTH
Note 1: I/O pins have diode protection to VDD and VSS.
FIGURE 10-23:
RH7:RH4 PINS BLOCK
DIAGRAM IN I/O MODE
RD LATH
Data
Bus
WR LATH
or
PORTH
D
I/O pin(1)
CK
Data Latch
D
WR TRISH
Q
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRISH
Value used to
initialize data
direction
Set RH3:RH0 as inputs
RH5:RH4 as outputs
RH7:RH6 as inputs
Q
D
ENEN
RD PORTH
To A/D Converter
Note 1: I/O pins have diode protection to VDD and VSS.
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FIGURE 10-24:
RH3:RH0 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
Q
D
ENEN
RD PORTH
RD LATD
Data Bus
WR LATH
or
PORTH
D
Q
Port
0
Data 1
CK
I/O pin(1)
Data Latch
D
WR TRISH
Q
CK
TRIS Latch
TTL
Input
Buffer
RD TRISH
External Enable
System Bus
Control
Address Out
Drive System
To Instruction Register
Instruction Read
Note 1: I/O pins have diode protection to VDD and VSS.
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TABLE 10-15: PORTH FUNCTIONS
Bit#
Buffer Type
RH0/A16
Name
bit 0
ST/TTL(1)
Input/output port pin or address bit 16 for external memory interface.
Function
RH1/A17
bit 1
ST/TTL(1)
Input/output port pin or address bit 17 for external memory interface.
RH2/A18
bit 2
ST/TTL(1)
Input/output port pin or address bit 18 for external memory interface.
RH3/A19
bit 3
ST/TTL(1)
Input/output port pin or address bit 19 for external memory interface.
RH4/AN12
bit 4
ST
RH5/AN13
bit 5
ST
Input/output port pin or analog input channel 13.
RH6/AN14/P1C(2)
bit 6
ST
Input/output port pin or analog input channel 14.
RH7/AN15/P1B(2)
bit 7
ST
Input/output port pin or analog input channel 15.
Input/output port pin or analog input channel 12.
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in System Bus or Parallel Slave
Port mode.
2: Alternate pin assignment when ECCPMX configuration bit is cleared.
TABLE 10-16: SUMMARY OF REGISTERS ASSOCIATED WITH PORTH
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
TRISH
PORTH Data Direction Control Register
1111 1111
1111 1111
PORTH
Read PORTH pin/Write PORTH Data Latch
xxxx xxxx
uuuu uuuu
LATH
Read PORTH Data Latch/Write PORTH Data Latch
xxxx xxxx
uuuu uuuu
—
VCFG1 VCFG0 PCFG3 PCFG2 PCFG1 PCFG0 --00 0000
--00 0000
—
WAIT1
0-00 --00
ADCON1
—
MEMCON(1) EBDIS
WAIT0
—
—
WM1
WM0
0-00 --00
Legend: x = unknown, u = unchanged, – = unimplemented. Shaded cells are not used by PORTH.
Note 1: This register is held in Reset in Microcontroller mode.
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10.9
Note:
PORTJ, TRISJ and LATJ
Registers
PORTJ is available only on PIC18F8X8X
devices.
FIGURE 10-25:
RD LATJ
PORTJ is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISJ. Setting a
TRISJ bit (= 1) will make the corresponding PORTJ pin
an input (i.e., put the corresponding output driver in a
high-impedance mode). Clearing a TRISJ bit (= 0) will
make the corresponding PORTJ pin an output (i.e., put
the contents of the output latch on the selected pin).
Data
Bus
The Data Latch register (LATJ) is also memory
mapped. Read-modify-write operations on the LATJ
register read and write the latched output value for
PORTJ.
WR TRISJ
PORTJ is multiplexed with the system bus as the
external memory interface; I/O port functions are only
available when the system bus is disabled. When
operating as the external memory interface, PORTJ
provides the control signal to external memory devices.
The RJ5 pin is not multiplexed with any system bus
functions.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTJ pin. Some
peripherals override the TRIS bit to make a pin an
output, while other peripherals override the TRIS bit to
make a pin an input. The user should refer to the
corresponding peripheral section for the correct TRIS
bit settings.
Note:
PORTJ BLOCK DIAGRAM
IN I/O MODE
WR LATJ
or
PORTJ
D
Q
I/O pin(1)
CK
Data Latch
D
Q
Schmitt
Trigger
Input
Buffer
CK
TRIS Latch
RD TRISJ
Q
D
EN
EN
RD PORTJ
Note 1: I/O pins have diode protection to VDD and VSS.
On a Power-on Reset, these pins are
configured as digital inputs.
The pin override value is not loaded into the TRIS register. This allows read-modify-write of the TRIS register
without concern due to peripheral overrides.
EXAMPLE 10-9:
CLRF
PORTJ
CLRF
LATJ
MOVLW
0CFh
MOVWF
TRISJ
INITIALIZING PORTJ
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTG by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RJ3:RJ0 as inputs
RJ5:RJ4 as output
RJ7:RJ6 as inputs
2003-2013 Microchip Technology Inc.
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FIGURE 10-26:
RJ5:RJ0 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
Q
D
EN
EN
RD PORTJ
RD LATJ
Data Bus
WR LATJ
or
PORTJ
D
Data
0
1
CK
I/O pin(1)
Data Latch
D
WR TRISJ
Port
Q
Q
CK
TRIS Latch
RD TRISJ
Control Out
System Bus
Control
External Enable
Drive System
Note 1: I/O pins have diode protection to VDD and VSS.
FIGURE 10-27:
RJ7:RJ6 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
Q
D
EN
EN
RD PORTJ
RD LATJ
Data Bus
D
Q
Port
Data
WR LATJ
or
PORTJ
CK
1
I/O pin(1)
Data Latch
D
WR TRISJ
0
Q
CK
TRIS Latch
RD TRISJ
UB/LB Out
System Bus
Control
WM = 01
Drive System
Note 1: I/O pins have diode protection to VDD and VSS.
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TABLE 10-17: PORTJ FUNCTIONS
Bit#
Buffer Type
RJ0/ALE
Name
bit 0
ST
Input/output port pin or address latch enable control for external
memory interface.
Function
RJ1/OE
bit 1
ST
Input/output port pin or output enable control for external memory
interface.
RJ2/WRL
bit 2
ST
Input/output port pin or write low byte control for external memory
interface.
RJ3/WRH
bit 3
ST
Input/output port pin or write high byte control for external memory
interface.
RJ4/BA0
bit 4
ST
Input/output port pin or byte address 0 control for external memory
interface.
RJ5/CE
bit 5
ST
Input/output port pin or external memory chip enable.
RJ6/LB
bit 6
ST
Input/output port pin or lower byte select control for external
memory interface.
RJ7/UB
bit 7
ST
Input/output port pin or upper byte select control for external
memory interface.
Legend: ST = Schmitt Trigger input
TABLE 10-18: SUMMARY OF REGISTERS ASSOCIATED WITH PORTJ
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
PORTJ
Read PORTJ pin/Write PORTJ Data Latch
xxxx xxxx
uuuu uuuu
LATJ
LATJ Data Output Register
xxxx xxxx
uuuu uuuu
TRISJ
Data Direction Control Register for PORTJ
1111 1111
1111 1111
Legend: x = unknown, u = unchanged
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10.10 Parallel Slave Port (PSP)
PORTD also operates as an 8-bit wide Parallel Slave
Port, or microprocessor port, when control bit
PSPMODE (TRISE) is set. It is asynchronously
readable and writable by the external world through RD
control input pin, RE0/RD/AD8 and WR control input
pin, RE1/WR/AD9.
Note:
For PIC18F8X8X devices, the Parallel
Slave Port is available only in
Microcontroller mode.
The PSP can directly interface to an 8-bit microprocessor data bus. The external microprocessor can
read or write the PORTD latch as an 8-bit latch. Setting
bit PSPMODE enables port pin RE0/RD/AD8 to be the
RD input, RE1/WR/AD9 to be the WR input and
RE2/CS/AD10 to be the CS (chip select) input. For this
functionality, the corresponding data direction bits of
the TRISE register (TRISE) must be configured
as inputs (set). The A/D port configuration bits
PCFG2:PCFG0 (ADCON1) must be set, which
will configure pins RE2:RE0 as digital I/O.
A write to the PSP occurs when both the CS and WR
lines are first detected low. A read from the PSP occurs
when both the CS and RD lines are first detected low.
The PORTE I/O pins become control inputs for
the microprocessor port when bit PSPMODE
(PSPCON) is set. In this mode, the user must make
sure that the TRISE bits are set (pins are configured as digital inputs) and the ADCON1 is configured
for digital I/O. In this mode, the input buffers are TTL.
FIGURE 10-28:
PORTD AND PORTE
BLOCK DIAGRAM
(PARALLEL SLAVE PORT)
Data Bus
D
WR LATD
or
PORTD
Q
RDx
pin
CK
Data Latch
Q
RD PORTD
TTL
D
ENEN
TRIS Latch
RD LATD
One bit of PORTD
Set Interrupt Flag
PSPIF (PIR1)
Read
TTL
RD
Chip Select
TTL
CS
Write
TTL
WR
Note: I/O pin has protection diodes to VDD and VSS.
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REGISTER 10-1:
PSPCON REGISTER
R-0
R-0
R/W-0
R/W-0
U-0
U-0
U-0
U-0
IBF
OBF
IBOV
PSPMODE
—
—
—
—
bit 7
bit 0
bit 7
IBF: Input Buffer Full Status bit
1 = A data byte has been received and is waiting to be read by the CPU
0 = No data byte has been received
bit 6
OBF: Output Buffer Full Status bit
1 = The output buffer still holds a previously written data byte
0 = The output buffer has been read
bit 5
IBOV: Input Buffer Overflow Detect bit
1 = A write occurred when a previously input data byte has not been read
(must be cleared in software)
0 = No overflow occurred
bit 4
PSPMODE: Parallel Slave Port Mode Select bit
1 = Parallel Slave Port mode
0 = General Purpose I/O mode
bit 3-0
Unimplemented: Read as ‘0’
Legend:
FIGURE 10-29:
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
PARALLEL SLAVE PORT WRITE WAVEFORMS
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
CS
WR
RD
PORTD
IBF
OBF
PSPIF
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FIGURE 10-30:
PARALLEL SLAVE PORT READ WAVEFORMS
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
CS
WR
RD
PORTD
IBF
OBF
PSPIF
TABLE 10-19: REGISTERS ASSOCIATED WITH PARALLEL SLAVE PORT
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
PORTD
Port Data Latch when Written; Port pins when Read
xxxx xxxx uuuu uuuu
LATD
LATD Data Output bits
xxxx xxxx uuuu uuuu
TRISD
PORTD Data Direction bits
PORTE
RE7/CCP2/ RE6/AD14/ RE5/AD13/
AD15
P1B
P1C
LATE
LATE Data Output bits
TRISE
PORTE Data Direction bits
1111 1111 1111 1111
RE4/
AD12
RE3/
AD11
RE2/CS(1)/ RE1/WR(1)/ RE0/RD(1)/ xxxx xxxx uuuu uuuu
AD10
AD9
AD8
xxxx xxxx uuuu uuuu
1111 1111 1111 1111
PSPCON
IBF
OBF
IBOV
PSPMODE
—
—
—
—
0000 ---- 0000 ----
INTCON
GIE/
GIEH
PEIE/
GIEL
TMR0IF
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000 0000 0000
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000 0000 0000
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000 0000 0000
IPR1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111 1111 1111
Legend:
Note 1:
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Parallel Slave Port.
Enabled only in Microcontroller mode.
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11.0
TIMER0 MODULE
The Timer0 module has the following features:
• Software selectable as an 8-bit or 16-bit timer/
counter
• Readable and writable
• Dedicated 8-bit software programmable prescaler
• Clock source selectable to be external or internal
• Interrupt-on-overflow from 0FFh to 00h in 8-bit
mode and 0FFFFh to 0000h in 16-bit mode
• Edge select for external clock
REGISTER 11-1:
Figure 11-1 shows a simplified block diagram of the
Timer0 module in 8-bit mode and Figure 11-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
The T0CON register (Register 11-1) is a readable and
writable register that controls all the aspects of Timer0,
including the prescale selection.
Note:
Timer0 is enabled on POR.
T0CON: TIMER0 CONTROL REGISTER
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
TMR0ON
T08BIT
T0CS
T0SE
PSA
T0PS2
T0PS1
T0PS0
bit 7
bit 0
bit 7
TMR0ON: Timer0 On/Off Control bit
1 = Enables Timer0
0 = Stops Timer0
bit 6
T08BIT: Timer0 8-bit/16-bit Control bit
1 = Timer0 is configured as an 8-bit timer/counter
0 = Timer0 is configured as a 16-bit timer/counter
bit 5
T0CS: Timer0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKO)
bit 4
T0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on T0CKI pin
bit 3
PSA: Timer0 Prescaler Assignment bit
1 = TImer0 prescaler is not assigned. Timer0 clock input bypasses prescaler.
0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
bit 2-0
T0PS2:T0PS0: Timer0 Prescaler Select bits
111 = 1:256 prescale value
110 = 1:128 prescale value
101 = 1:64 prescale value
100 = 1:32 prescale value
011 = 1:16 prescale value
010 = 1:8 prescale value
001 = 1:4 prescale value
000 = 1:2 prescale value
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
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x = Bit is unknown
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FIGURE 11-1:
TIMER0 BLOCK DIAGRAM IN 8-BIT MODE
Data Bus
FOSC/4
0
8
0
1
RA4/T0CKI pin
Programmable
Prescaler
1
Sync with
Internal
Clocks
TMR0
(2 TCY delay)
T0SE
3
PSA
Set Interrupt
Flag bit TMR0IF
on Overflow
T0PS2, T0PS1, T0PS0
T0CS
Note:
Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
FIGURE 11-2:
FOSC/4
TIMER0 BLOCK DIAGRAM IN 16-BIT MODE
0
0
1
Programmable
Prescaler
T0CKI pin
1
Sync with
Internal
Clocks
TMR0L
TMR0
High Byte
8
(2 TCY delay)
T0SE
3
Read TMR0L
T0PS2, T0PS1, T0PS0
T0CS
Set Interrupt
Flag bit TMR0IF
on Overflow
Write TMR0L
PSA
8
8
TMR0H
8
Data Bus
Note:
Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
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11.1
Timer0 Operation
11.2.1
Timer0 can operate as a timer or as a counter.
The prescaler assignment is fully under software
control (i.e., it can be changed “on-the-fly” during
program execution).
Timer mode is selected by clearing the T0CS bit. In
Timer mode, the Timer0 module will increment every
instruction cycle (without prescaler). If the TMR0 register is written, the increment is inhibited for the following
two instruction cycles. The user can work around this
by writing an adjusted value to the TMR0 register.
11.3
When an external clock input is used for Timer0, it must
meet certain requirements. The requirements ensure
the external clock can be synchronized with the internal
phase clock (TOSC). Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
11.4
An 8-bit counter is available as a prescaler for the
Timer0 module. The prescaler is not readable or
writable.
The PSA and T0PS2:T0PS0 bits determine the
prescaler assignment and prescale ratio.
Clearing bit PSA will assign the prescaler to the Timer0
module. When the prescaler is assigned to the Timer0
module, prescale values of 1:2, 1:4, ..., 1:256 are
selectable.
A write to the high byte of Timer0 must also take place
through the TMR0H buffer register. Timer0 high byte is
updated with the contents of TMR0H when a write
occurs to TMR0L. This allows all 16 bits of Timer0 to be
updated at once.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF TMR0, MOVWF
TMR0, BSF TMR0, x, ..., etc.) will clear the prescaler
count.
Writing to TMR0 when the prescaler is
assigned to Timer0 will clear the prescaler
count but will not change the prescaler
assignment.
TABLE 11-1:
Name
16-Bit Mode Timer Reads
and Writes
TMR0H is not the high byte of the timer/counter in
16-bit mode, but is actually a buffered version of the
high byte of Timer0 (refer to Figure 11-2). The high byte
of the Timer0 counter/timer is not directly readable nor
writable. TMR0H is updated with the contents of the
high byte of Timer0 during a read of TMR0L. This provides the ability to read all 16 bits of Timer0 without
having to verify that the read of the high and low byte
were valid due to a rollover between successive reads
of the high and low byte.
Prescaler
Note:
Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0 register overflows from 0FFh to 00h in 8-bit mode, or
0FFFFh to 0000h in 16-bit mode. This overflow sets the
TMR0IF bit. The interrupt can be masked by clearing
the TMR0IE bit. The TMR0IE bit must be cleared in
software by the Timer0 module Interrupt Service
Routine before re-enabling this interrupt. The TMR0
interrupt cannot awaken the processor from Sleep
since the timer is shut-off during Sleep.
Counter mode is selected by setting the T0CS bit. In
Counter mode, Timer0 will increment either on every
rising or falling edge of pin RA4/T0CKI. The incrementing edge is determined by the Timer0 Source Edge
Select bit (T0SE). Clearing the T0SE bit selects the
rising edge. Restrictions on the external clock input are
discussed below.
11.2
SWITCHING PRESCALER
ASSIGNMENT
REGISTERS ASSOCIATED WITH TIMER0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
TMR0L
Timer0 Module Low Byte Register
TMR0H
Timer0 Module High Byte Register
INTCON
GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE
TMR0IF INT0IF
T0CON
TMR0ON
PSA
T0PS2
TRISA
—
T08BIT
T0CS
Bit 0
Value on
POR, BOR
Value on
all other
Resets
xxxx xxxx uuuu uuuu
0000 0000 0000 0000
T0SE
PORTA Data Direction Register
T0PS1
RBIF
0000 000x 0000 000u
T0PS0 1111 1111 1111 1111
-111 1111 -111 1111
Legend: x = unknown, u = unchanged, – = unimplemented locations, read as ‘0’. Shaded cells are not used by
Timer0.
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NOTES:
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12.0
TIMER1 MODULE
Figure 12-1 is a simplified block diagram of the Timer1
module.
The Timer1 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers; TMR1H and TMR1L)
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt on overflow from 0FFFFh to 0000h
• Reset from CCP module special event trigger
REGISTER 12-1:
Register 12-1 details the Timer1 Control register. This
register controls the operating mode of the Timer1
module and contains the Timer1 Oscillator Enable bit
(T1OSCEN). Timer1 can be enabled or disabled by
setting or clearing control bit, TMR1ON (T1CON).
T1CON: TIMER1 CONTROL REGISTER
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
RD16
—
T1CKPS1
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON
bit 7
bit 0
bit 7
RD16: 16-bit Read/Write Mode Enable bit
1 = Enables register read/write of Timer1 in one 16-bit operation
0 = Enables register read/write of Timer1 in two 8-bit operations
bit 6
Unimplemented: Read as ‘0’
bit 5-4
T1CKPS1:T1CKPS0: Timer1 Input Clock Prescale Select bits
11 = 1:8 prescale value
10 = 1:4 prescale value
01 = 1:2 prescale value
00 = 1:1 prescale value
bit 3
T1OSCEN: Timer1 Oscillator Enable bit
1 = Timer1 oscillator is enabled
0 = Timer1 oscillator is shut-off
The oscillator inverter and feedback resistor are turned off to eliminate power drain.
bit 2
T1SYNC: Timer1 External Clock Input Synchronization Select bit
When TMR1CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR1CS = 0:
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
bit 1
TMR1CS: Timer1 Clock Source Select bit
1 = External clock from pin RC0/T1OSO/T13CKI (on the rising edge)
0 = Internal clock (FOSC/4)
bit 0
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
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x = Bit is unknown
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12.1
Timer1 Operation
When TMR1CS = 0, Timer1 increments every instruction cycle. When TMR1CS = 1, Timer1 increments on
every rising edge of the external clock input or the
Timer1 oscillator if enabled.
Timer1 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
The operating mode is determined by the clock select
bit, TMR1CS (T1CON).
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T13CKI pins
become inputs. That is, the TRISC value is
ignored and the pins are read as ‘0’.
Timer1 also has an internal “Reset input”. This Reset
can be generated by the CCP module (Section 15.0
“Capture/Compare/PWM (CCP) Modules”).
FIGURE 12-1:
TIMER1 BLOCK DIAGRAM
CCP Special Event Trigger
TMR1IF
Overflow
Interrupt
Flag Bit
TMR1
TMR1H
1
TMR1ON
On/Off
T1OSC
T13CKI/T1OSO
T1OSCEN
Enable
Oscillator(1)
T1OSI
Synchronized
Clock Input
0
CLR
TMR1L
T1SYNC
1
Synchronize
Prescaler
1, 2, 4, 8
FOSC/4
Internal
Clock
det
0
2
T1CKPS1:T1CKPS0
Sleep Input
TMR1CS
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
FIGURE 12-2:
TIMER1 BLOCK DIAGRAM: 16-BIT READ/WRITE MODE
Data Bus
8
TMR1H
8
8
Write TMR1L
CCP Special Event Trigger
Read TMR1L
TMR1IF
Overflow
Interrupt
Flag bit
TMR1
8
Timer 1
High Byte
TMR1L
1
TMR1ON
On/Off
T1OSC
T1SYNC
1
T13CKI/T1OSO
T1OSI
Synchronized
Clock Input
0
CLR
T1OSCEN
Enable
Oscillator(1)
FOSC/4
Internal
Clock
Prescaler
1, 2, 4, 8
Synchronize
det
0
2
Sleep Input
TMR1CS
T1CKPS1:T1CKPS0
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
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12.2
Timer1 Oscillator
12.4
A crystal oscillator circuit is built-in between pins T1OSI
(input) and T1OSO (amplifier output). It is enabled by
setting control bit, T1OSCEN (T1CON). The oscillator is a low-power oscillator rated up to 200 kHz. It will
continue to run during Sleep. It is primarily intended for
a 32 kHz crystal. Table 12-1 shows the capacitor
selection for the Timer1 oscillator.
If the CCP module is configured in Compare mode
to
generate
a
“special
event
trigger”
(CCP1M3:CCP1M0 = 1011), this signal will reset
Timer1 and start an A/D conversion (if the A/D module
is enabled).
Note:
The user must provide a software time delay to ensure
proper start-up of the Timer1 oscillator.
TABLE 12-1:
Resetting Timer1 Using a CCP
Trigger Output
CAPACITOR SELECTION
FOR THE ALTERNATE
OSCILLATOR
The special event triggers from the CCP1
module will not set interrupt flag bit
TMR1IF (PIR1).
Timer1 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature.
If Timer1 is running in Asynchronous Counter mode,
this Reset operation may not work.
Osc Type
Freq
C1
C2
LP
32 kHz
TBD(1)
TBD(1)
In the event that a write to Timer1 coincides with a
special event trigger from CCP1, the write will take
precedence.
20 PPM
In this mode of operation, the CCPR1H:CCPR1L register
pair effectively becomes the period register for Timer1.
Crystal to be Tested:
32.768 kHz Epson C-001R32.768K-A
Note 1: Microchip suggests 33 pF as a starting
point in validating the oscillator circuit.
12.5
2: Higher capacitance increases the stability
of the oscillator but also increases the
start-up time.
Timer1 can be configured for 16-bit reads and writes
(see Figure 12-2). When the RD16 control bit
(T1CON) is set, the address for TMR1H is mapped
to a buffer register for the high byte of Timer1. A read
from TMR1L will load the contents of the high byte of
Timer1 into the Timer1 high byte buffer. This provides
the user with the ability to accurately read all 16 bits of
Timer1 without having to determine whether a read of
the high byte, followed by a read of the low byte, is valid
due to a rollover between reads.
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate
values
of
external
components.
4: Capacitor values are for design guidance
only.
12.3
A write to the high byte of Timer1 must also take place
through the TMR1H Buffer register. Timer1 high byte is
updated with the contents of TMR1H when a write
occurs to TMR1L. This allows a user to write all 16 bits
to both the high and low bytes of Timer1 at once.
Timer1 Interrupt
The TMR1 register pair (TMR1H:TMR1L) increments
from 0000h to 0FFFFh and rolls over to 0000h. The
TMR1 interrupt, if enabled, is generated on overflow
which is latched in interrupt flag bit, TMR1IF
(PIR1). This interrupt can be enabled/disabled by
setting/clearing TMR1 interrupt enable bit, TMR1IE
(PIE1).
TABLE 12-2:
Name
Timer1 16-Bit Read/Write Mode
The high byte of Timer1 is not directly readable or writable in this mode. All reads and writes must take place
through the Timer1 High Byte Buffer register. Writes to
TMR1H do not clear the Timer1 prescaler. The
prescaler is only cleared on writes to TMR1L.
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
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
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000 0000 0000
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000 0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000 0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
0111 1111 0111 1111
INTCON
GIE/GIEH PEIE/GIEL
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
T1CON
Legend:
RD16
—
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 u-uu uuuu
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
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13.0
TIMER2 MODULE
13.1
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 of PR2
SSP module optional use of TMR2 output to
generate clock shift
Timer2 has a control register shown in Register 13-1.
Timer2 can be shut-off by clearing control bit, TMR2ON
(T2CON), to minimize power consumption.
Figure 13-1 is a simplified block diagram of the Timer2
module. Register 13-1 shows the Timer2 Control register. The prescaler and postscaler selection of Timer2
are controlled by this register.
REGISTER 13-1:
Timer2 Operation
Timer2 can be used as the PWM time base for the
PWM mode of the CCP 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,
T2CKPS1:T2CKPS0 (T2CON). 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).
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.
T2CON: TIMER2 CONTROL REGISTER
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6-3
T2OUTPS3:T2OUTPS0: 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
T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
1x = Prescaler is 16
Legend:
DS30491D-page 162
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
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13.2
Timer2 Interrupt
13.3
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 0FFh upon Reset.
FIGURE 13-1:
Output of TMR2
The output of TMR2 (before the postscaler) is fed to the
synchronous serial port module which optionally uses it
to generate the shift clock.
TIMER2 BLOCK DIAGRAM
Sets Flag
bit TMR2IF
TMR2
Output(1)
Prescaler
1:1, 1:4, 1:16
FOSC/4
2
Reset
TMR2
Comparator
EQ
Postscaler
1:1 to 1:16
T2CKPS1:T2CKPS0
4
PR2
T2OUTPS3:T2OUTPS0
Note 1: TMR2 register output can be software selected by the SSP module as a baud clock.
TABLE 13-1:
Name
Bit 7
REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Value on
all other
Resets
Bit 0
Value on
POR, BOR
RBIF
0000 0000 0000 0000
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF 0000 0000 0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE 0000 0000 0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP 1111 1111 1111 1111
INTCON GIE/GIEH PEIE/GIEL
TMR2
T2CON
PR2
Legend:
Timer2 Module Register
—
0000 0000 0000 0000
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Timer2 Period Register
1111 1111 1111 1111
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.
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14.0
TIMER3 MODULE
Figure 14-1 is a simplified block diagram of the Timer3
module.
The Timer3 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers; TMR3H and TMR3L)
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt on overflow from FFFFh to 0000h
• Reset from CCP module trigger
REGISTER 14-1:
Register 14-1 shows the Timer3 Control register. This
register controls the operating mode of the Timer3
module and sets the Enhanced CCP1 and CCP2 clock
source.
Register 12-1 shows the Timer1 Control register. This
register controls the operating mode of the Timer1
module, as well as containing the Timer1 oscillator
enable bit (T1OSCEN) which can be a clock source for
Timer3.
T3CON: TIMER3 CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
RD16
T3CCP2
T3CKPS1
T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
bit 7
bit 0
bit 7
RD16: 16-bit Read/Write Mode Enable bit
1 = Enables register read/write of Timer3 in one 16-bit operation
0 = Enables register read/write of Timer3 in two 8-bit operations
bit 6, 3
T3CCP2:T3CCP1: Timer3 and Timer1 to CCPx Enable bits
1x = Timer3 is the clock source for compare/capture of CCP1 and CCP2 modules
01 = Timer3 is the clock source for compare/capture of CCP2 module,
Timer1 is the clock source for compare/capture of CCP1 module
00 = Timer1 is the clock source for compare/capture of CCP1 and CCP2 modules
bit 5-4
T3CKPS1:T3CKPS0: Timer3 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 2
T3SYNC: Timer3 External Clock Input Synchronization Control bit
(Not usable if the system clock comes from Timer1/Timer3.)
When TMR3CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR3CS = 0:
This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.
bit 1
TMR3CS: Timer3 Clock Source Select bit
1 = External clock input from Timer1 oscillator or T13CKI
(on the rising edge after the first falling edge)
0 = Internal clock (FOSC/4)
bit 0
TMR3ON: Timer3 On bit
1 = Enables Timer3
0 = Stops Timer3
Legend:
DS30491D-page 164
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
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14.1
Timer3 Operation
When TMR3CS = 0, Timer3 increments every instruction cycle. When TMR3CS = 1, Timer3 increments on
every rising edge of the Timer1 external clock input or
the Timer1 oscillator if enabled.
Timer3 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T13CKI pins
become inputs. That is, the TRISC value is
ignored and the pins are read as ‘0’.
The operating mode is determined by the clock select
bit, TMR3CS (T3CON).
Timer3 also has an internal “Reset input”. This Reset
can be generated by the CCP module (Section 14.0
“Timer3 Module”).
FIGURE 14-1:
TIMER3 BLOCK DIAGRAM
CCP Special Trigger
T3CCPx
TMR3IF
Overflow
Interrupt
Flag bit
TMR3H
Synchronized
Clock Input
0
CLR
TMR3L
1
TMR3ON
On/Off
T1OSC
T1OSO/
T13CKI
T3SYNC
(3)
1
T1OSCEN FOSC/4
Enable
Internal
Oscillator(1) Clock
T1OSI
Synchronize
Prescaler
1, 2, 4, 8
det
0
2
TMR3CS
T3CKPS1:T3CKPS0
Sleep Input
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
FIGURE 14-2:
TIMER3 BLOCK DIAGRAM CONFIGURED IN 16-BIT READ/WRITE MODE
Data Bus
8
TMR3H
8
8
Write TMR3L
Read TMR3L
Set TMR3IF Flag bit
on Overflow
8
CCP Special Trigger
T3CCPx
0
TMR3
Timer3
High Byte
TMR3L
CLR
Synchronized
Clock Input
1
To Timer1 Clock Input
T1OSO/
T13CKI
T1OSI
TMR3ON
On/Off
T1OSC
T3SYNC
1
T1OSCEN
Enable
Oscillator(1)
FOSC/4
Internal
Clock
Prescaler
1, 2, 4, 8
Synchronize
det
0
2
T3CKPS1:T3CKPS0
TMR3CS
Sleep Input
Note 1: When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
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14.2
Timer1 Oscillator
14.4
The Timer1 oscillator may be used as the clock source
for Timer3. The Timer1 oscillator is enabled by setting
the T1OSCEN (T1CON) bit. The oscillator is a lowpower oscillator rated up to 200 kHz. See Section 12.0
“Timer1 Module” for further details.
14.3
The TMR3 register pair (TMR3H:TMR3L) increments
from 0000h to 0FFFFh and rolls over to 0000h. The
TMR3 interrupt, if enabled, is generated on overflow
which is latched in interrupt flag bit, TMR3IF
(PIR2). This interrupt can be enabled/disabled by
setting/clearing TMR3 interrupt enable bit, TMR3IE
(PIE2).
TABLE 14-1:
If the CCP module is configured in Compare mode
to
generate
a
“special
event
trigger”
(CCP1M3:CCP1M0 = 1011), this signal will reset
Timer3.
Note:
Timer3 Interrupt
Resetting Timer3 Using a CCP
Trigger Output
The special event triggers from the CCP
module will not set interrupt flag bit,
TMR3IF (PIR1).
Timer3 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature.
If Timer3 is running in Asynchronous Counter mode,
this Reset operation may not work. In the event that a
write to Timer3 coincides with a special event trigger
from CCP1, the write will take precedence. In this mode
of operation, the CCPR1H:CCPR1L register pair
effectively becomes the period register for Timer3.
REGISTERS ASSOCIATED WITH TIMER3 AS A TIMER/COUNTER
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
INTCON
GIE/
GIEH
PEIE/
GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000 0000 0000
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
CCP2IF
-0-0 0000 -0-0 0000
PIE2
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE
CCP2IE
-0-0 0000 -0-0 0000
—
CMIP
—
EEIP
BCLIP
LVDIP
TMR3IP
CCP2IP
-1-1 1111 -1-1 1111
IPR2
TMR3L
Holding Register for the Least Significant Byte of the 16-bit TMR3 Register
xxxx xxxx uuuu uuuu
TMR3H
Holding Register for the Most Significant Byte of the 16-bit TMR3 Register
xxxx xxxx uuuu uuuu
T1CON
RD16
—
T3CON
RD16
T3CCP2
Legend:
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Timer3 module.
DS30491D-page 166
T1CKPS1 T1CKPS0 T1OSCEN
T1SYNC
TMR1CS TMR1ON 0-00 0000 u-uu uuuu
T3CKPS1 T3CKPS0
T3SYNC
TMR3CS TMR3ON 0000 0000 uuuu uuuu
T3CCP1
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15.0
CAPTURE/COMPARE/PWM
(CCP) MODULES
Additionally, the CCP2 special event trigger may be
used to start an A/D conversion if the A/D module is
enabled.
PIC18FXX80/XX85 devices contain a total of two CCP
modules: CCP1 and CCP2. CCP1 is an enhanced
version of the CCP2 module. CCP1 is fully backward
compatible with the CCP2 module.
The CCP1 module differs from CCP2 in the following
respect:
• CCP1 contains a special trigger event that may
reset Timer1 or the Timer3 register pair
• CCP1 contains “CAN Message Time-Stamp Trigger”
• CCP1 contains enhanced PWM output with
programmable dead band and auto-shutdown
functionality
REGISTER 15-1:
To avoid duplicate information, this section describes
basic CCP module operation that applies to both CCP1
and CCP2. Enhanced CCP functionality of the
CCP1 module is described in Section 16.0 “Enhanced
Capture/Compare/PWM (ECCP) Module”.
The control registers for the CCP1 and CCP2 modules
are shown in Register 15-1 and Register 15-2,
respectively. Table 15-2 details the interactions of the
CCP and ECCP modules.
CCP1CON REGISTER
R/W-0
P1M1
bit 7
R/W-0
P1M0
R/W-0
DC1B1
R/W-0
DC1B0
R/W-0
CCP1M3
R/W-0
CCP1M2
R/W-0
CCP1M1
R/W-0
CCP1M0
bit 0
bit 7-6
P1M1:P1M0: Enhanced PWM Output Configuration bits
If CCP1M = 00, 01, 10:
xx =P1A assigned as capture/compare input; P1B, P1C, P1D assigned as port pins
If CCP1M = 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
DC1B1:DC1B0: PWM Duty Cycle bit 1 and bit 0
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the 10-bit PWM duty cycle. The eight MSbs of the duty cycle are
found in CCPR1L.
bit 3-0
CCP1M3:CCP1M0: Enhanced CCP Mode Select bits
0000 = Capture/Compare/PWM off (resets CCP1 module)
0001 = Reserved
0010 = Compare mode, toggle output on match
0011 = 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, initialize CCP pin low, on compare match force CCP pin high
1001 = Compare mode, initialize CCP pin high, on compare match force CCP pin low
1010 = Compare mode, generate software interrupt only, CCP pin is unaffected
1011 = Compare mode, trigger special event, resets TMR1 or TMR3
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
Legend:
R = Readable bit
- n = Value at POR
2003-2013 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
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REGISTER 15-2:
CCP2CON REGISTER
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
DC2B1
DC2B0
CCP2M3
CCP2M2
CCP2M1
CCP2M0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
DC2B1:DC2B0: PWM Duty Cycle bit 1 and bit 0
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the 10-bit PWM duty cycle. The eight MSbs of the duty cycle are
found in CCPR2L.
bit 3-0
CCP2M3:CCP2M0: CCP2 Mode Select bits
0000 = Capture/Compare/PWM off (resets CCP2 module)
0001 = Reserved
0010 = Compare mode, toggle output on match
0011 = 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, initialize CCP pin low, on compare match force CCP pin high
1001 = Compare mode, initialize CCP pin high, on compare match force CCP pin low
1010 = Compare mode, generate software interrupt only, CCP pin is unaffected
1011 = Compare mode, trigger special event, resets TMR1 or TMR3 and starts A/D conversion
if A/D module is enabled
11xx = PWM mode
Legend:
DS30491D-page 168
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
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15.1
CCP Module
Both CCP1 and CCP2 are comprised of two 8-bit
registers: CCPRxL (low byte) and CCPRxH (high byte),
1 x 2. The CCPxCON register controls the
operation of CCPx. All are readable and writable.
An event is selected by control bits CCPxM3:CCPxM0
(CCPxCON). When a capture is made, the interrupt request flag bit, CCPxIF (PIR registers), is set. It
must be cleared in software. If another capture occurs
before the value in register CCPRx is read, the old
captured value will be lost.
Table 15-1 shows the timer resources of the CCP
module modes.
15.2.1
TABLE 15-1:
In Capture mode, the CCPx pin should be configured
as an input by setting the appropriate TRIS bit.
CCP MODE – TIMER
RESOURCE
CCP Mode
Timer Resource
Capture
Compare
PWM
Timer1 or Timer3
Timer1 or Timer3
Timer2
15.2
Capture Mode
In Capture mode, CCPRxH:CCPRxL captures the
16-bit value of the TMR1 or TMR3 register when an
event occurs on pin CCPn. An event is defined as:
•
•
•
•
Note:
15.2.2
CCP PIN CONFIGURATION
If the CCPx is configured as an output, a
write to the port can cause a capture
condition.
TIMER1/TIMER3 MODE SELECTION
The timer used with each CCP module is selected in
the T3CCP2:T3CCP1 bits of the T3CON register. The
timers used with the capture feature (either Timer1 or
Timer3) must be running in Timer mode or Synchronized Counter mode. In Asynchronous Counter mode,
the capture operation may not work.
every falling edge
every rising edge
every 4th rising edge
every 16th rising edge
TABLE 15-2:
CCP1
Mode
INTERACTION OF CCP MODULES
CCP2
Mode
Interaction
Capture
Capture
TMR1 or TMR3 time base. Time base can be different for each CCP.
Capture
Compare
The compare could be configured for the special event trigger which clears either TMR1
or TMR3 depending upon which time base is used.
Compare
Compare
The compare(s) could be configured for the special event trigger which clears TMR1 or
TMR3 depending upon which time base is used.
PWM
PWM
The PWMs will have the same frequency and update rate (TMR2 interrupt).
PWM
Capture
None.
PWM
Compare
None.
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15.2.3
SOFTWARE INTERRUPT
15.2.5
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep bit
CCPxIE (PIE registers) clear to avoid false interrupts
and should clear the flag bit, CCPxIF, following any
such change in operating mode.
15.2.4
CCP PRESCALER
There are four prescaler settings specified by bits
CCPxM3:CCPxM0. Whenever the CCPx module is
turned off, or the CCPx module is not in Capture mode,
the prescaler counter is cleared. This means that any
Reset will clear the prescaler counter.
Switching from one capture prescaler to another may
generate an interrupt. The prescaler counter will not be
cleared; therefore, the first capture may be from a
non-zero prescaler. Example 15-1 shows the
recommended method for switching between capture
prescalers. This example also clears the prescaler
counter and will not generate the “false” interrupt.
FIGURE 15-1:
CAN MESSAGE TIME-STAMP
The CAN capture event occurs when a message is
received in any of the receive buffers. When configured, the CAN module provides the trigger to the CCP1
module to cause a capture event. This feature is
provided to time-stamp the received CAN messages.
This feature is enabled by setting the CANCAP bit of
the CAN I/O Control register (CIOCON). The
message receive signal from the CAN module then
takes the place of the events on RC2/CCP1.
EXAMPLE 15-1:
CHANGING BETWEEN
CAPTURE PRESCALERS
CLRF
MOVLW
CCP1CON
NEW_CAPT_PS
MOVWF
CCP1CON
;
;
;
;
;
;
Turn CCP module off
Load WREG with the
new prescaler mode
value and CCP ON
Load CCP1CON with
this value
CAPTURE MODE OPERATION BLOCK DIAGRAM
TMR3H
TMR3L
Set Flag bit CCP1IF
T3CCP2
Prescaler
1, 4, 16
CCP1 pin
TMR3
Enable
CCPR1H
and
Edge Detect
T3CCP2
CCPR1L
TMR1
Enable
TMR1H
TMR1L
TMR3H
TMR3L
CCP1CON
Q’s
Set Flag bit CCP2IF
T3CCP1
T3CCP2
TMR3
Enable
Prescaler
1, 4, 16
CCP2 pin
CCPR2H
and
Edge Detect
CCPR2L
TMR1
Enable
T3CCP2
T3CCP1
TMR1H
TMR1L
CCP2CON
Q’s
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15.3
Compare Mode
15.3.2
The timer used with each CCP module is selected in
the T3CCP2:T3CCP1 bits of the T3CON register.
Timer1 and/or Timer3 must be running in Timer mode,
or Synchronized Counter mode, if the CCP module is
using the compare feature. In Asynchronous Counter
mode, the compare operation may not work.
In Compare mode, the 16-bit CCPRx register value is
constantly compared against either the TMR1 register
pair value or the TMR3 register pair value. When a
match occurs, the CCPx pin can have one of the
following actions:
•
•
•
•
Driven high
Driven low
Toggle output (high-to-low or low-to-high)
Remains unchanged
15.3.3
15.3.4
The special event trigger output of CCP1 resets either
the TMR1 or TMR3 register pair. This allows the CCPR1
register to effectively be a 16-bit programmable period
register for TMR1 or TMR3.
CCP PIN CONFIGURATION
The user must configure the CCPx pin as an output by
clearing the appropriate TRIS bit.
Additionally, the CCP2 special event trigger will start an
A/D conversion if the A/D module is enabled.
By default, the CCP2 pin is multiplexed with RC1.
Alternately, it can also be multiplexed with either RB3
or RE7. This is done by changing the CCP2MX
configuration bit.
Note:
Clearing the CCPxCON register will force
the CCPx compare output latch to the
default low level. This is not the data latch.
FIGURE 15-2:
SPECIAL EVENT TRIGGER
In this mode, an internal hardware trigger is generated
which may be used to initiate an action.
When configured to drive the CCP pin, the CCP1 pin
cannot be changed; CCP1 module controls the pin.
Note:
SOFTWARE INTERRUPT MODE
When generate software interrupt is chosen, the CCPx
pin is not affected. Only a CCP interrupt is generated (if
enabled).
The action on the pin is based on the value of control
bits, CCPxM3:CCPxM0. At the same time, interrupt
flag bit, CCPxIF, is set.
15.3.1
TIMER1/TIMER3 MODE SELECTION
The special event trigger from the CCPx
module will not set the Timer1 or Timer3
interrupt flag bits.
COMPARE MODE OPERATION BLOCK DIAGRAM
Special Event Trigger will:
Reset Timer1 or Timer3, but not set Timer1 or Timer3 interrupt flag bit
and set bit GO/DONE (ADCON0)
which starts an A/D conversion (CCP2 only)
Set Flag bit CCP1IF
CCPR1H CCPR1L
Q
RC2/CCP1 pin
S
R
TRISC
Output Enable
Output
Logic
Comparator
Match
CCP1CON
Mode Select
0
T3CCP2
TMR1H
1
TMR1L
TMR3H
TMR3L
Special Event Trigger
Set Flag bit CCP2IF
Q
RC1/CCP2 pin
S
R
TRISC
Output Enable
2003-2013 Microchip Technology Inc.
Output
Logic
T3CCP1
T3CCP2
0
1
Comparator
Match
CCPR2H CCPR2L
CCP2CON
Mode Select
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TABLE 15-3:
REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, TIMER1 AND TIMER3
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
INTCON
GIE/
GIEH
PEIE/
GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x 0000 000u
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000 0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000 0000 0000
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111 1111 1111
IPR1
TRISD
PORTD Data Direction Register
1111 1111 1111 1111
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
T1CON
RD16
—
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
CCPR1L
Capture/Compare/PWM Register 1 (LSB)
CCPR1H
Capture/Compare/PWM Register 1 (MSB)
CCP1CON
P1M1
P1M0
DC1B1
DC1B0
xxxx xxxx uuuu uuuu
TMR1CS
TMR1ON 0-00 0000 u-uu uuuu
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCP1M3
CCP1M2
CCP1M1
CCP1M0 0000 0000 0000 0000
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
CCP2IF
-0-0 0000 -0-0 0000
PIE2
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE
CCP2IE
-0-0 0000 -0-0 0000
—
CMIP
—
EEIP
BCLIP
LVDIP
TMR3IP
CCP2IP
-1-1 1111 -1-1 1111
IPR2
TMR3L
Holding Register for the Least Significant Byte of the 16-bit TMR3 Register
TMR3H
Holding Register for the Most Significant Byte of the 16-bit TMR3 Register
T3CON
Legend:
RD16
T3CCP2
T3CKPS1 T3CKPS0
T3CCP1
T3SYNC
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
TMR3CS
TMR3ON 0000 0000 uuuu uuuu
x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by capture and Timer1.
DS30491D-page 172
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15.4
PWM Mode
15.4.1
In Pulse Width Modulation (PWM) mode, the CCPx pin
produces up to a 10-bit resolution PWM output. For
PWM mode to function properly, the TRIS bit for the
CCPx pin must be cleared to make it an output.
Note:
Clearing the CCPxCON register will force
the CCPx PWM output latch to the default
low level. This is not the port data latch.
Figure 15-3 shows a simplified block diagram of the
CCP module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 15.4.3
“Setup for PWM Operation”.
FIGURE 15-3:
SIMPLIFIED PWM BLOCK
DIAGRAM
Duty Cycle Registers
CCPxCON
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula.
EQUATION 15-1:
PWM Period = [(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
PWM frequency is defined as 1/[PWM period].
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCP1 pin is set (exception: if PWM duty
cycle = 0%, the CCP1 pin will not be set)
• The PWM duty cycle is latched from CCPR1L into
CCPR1H
Note:
CCPRxL (Master)
CCPRxH (Slave)
R
Comparator
15.4.2
Q
CCPx
(Note 1)
TMR2
S
TRIS bit
Comparator
Clear Timer,
set CCPx pin and
latch D.C.
PR2
Note 1: 8-bit timer is concatenated with 2-bit internal Q clock or
2 bits of the prescaler to create 10-bit time base.
A PWM output (Figure 15-4) has a time base (period)
and a time that the output stays high (duty cycle). The
frequency of the PWM is the inverse of the period
(1/period).
FIGURE 15-4:
PWM OUTPUT
PWM PERIOD
The Timer2 postscaler (see Section 13.0
“Timer2 Module”) 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
CCPRxL register and to the CCPxCON bits. Up
to 10-bit resolution is available. The CCPRxL contains
the eight MSbs and the CCPxCON contain the
two LSbs. This 10-bit value is represented by
CCPRxL:CCPxCON. The following equation is
used to calculate the PWM duty cycle in time.
EQUATION 15-2:
PWM Duty Cycle = (CCPRxL:CCPxCON) •
TOSC • (TMR2 Prescale Value)
CCPRxL and CCPxCON can be written to at any
time but the duty cycle value is not latched into
CCPRxH until after a match between PR2 and TMR2
occurs (i.e., the period is complete). In PWM mode,
CCPRxH is a read-only register.
The CCPRxH register and a 2-bit internal latch are
used to double-buffer the PWM duty cycle. This
double-buffering is essential for glitchless PWM
operation.
Period
Duty Cycle
TMR2 = PR2
When the CCPRxH and 2-bit latch match TMR2,
concatenated with an internal 2-bit Q clock or 2 bits of
the TMR2 prescaler, the CCPx pin is cleared.
TMR2 = Duty Cycle
TMR2 = PR2
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15.4.3
The maximum PWM resolution (bits) for a given PWM
frequency is given by the following equation.
The following steps should be taken when configuring
the CCP module for PWM operation:
EQUATION 15-3:
1.
F OSC
log ---------------
F PWM
PWM Resolution (max) = -----------------------------bits
log 2
2.
3.
Note:
5.
Set the PWM period by writing to the PR2
register.
Set the PWM duty cycle by writing to the
CCPRxL register and CCPxCON bits.
Make the CCPx pin an output by clearing
corresponding TRIS bit.
Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
Configure the CCPx module for PWM operation.
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
PWM Frequency
2.44 kHz
9.76 kHz
39.06 kHz
156.3 kHz
312.5 kHz
16
4
1
1
1
1
0FFh
0FFh
0FFh
3Fh
1Fh
17h
10
10
10
8
7
5.5
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
TABLE 15-5:
Name
4.
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
TABLE 15-4:
SETUP FOR PWM OPERATION
416.6 kHz
REGISTERS ASSOCIATED WITH PWM AND TIMER2
Bit 7
Bit 6
Bit 5
Bit 3
Bit 2
Bit 1
Value on
all other
Resets
Bit 0
Value on
POR, BOR
0000 000x 0000 000u
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000 0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000 0000 0000
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111 1111 1111
INTCON
IPR1
GIE/GIEH PEIE/GIEL TMR0IE
Bit 4
TRISC
PORTC Data Direction Register
1111 1111 1111 1111
TMR2
Timer2 Module Register
0000 0000 0000 0000
PR2
Timer2 Module Period Register
1111 1111 1111 1111
T2CON
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
CCPR1L
Capture/Compare/PWM Register 1 (LSB)
CCPR1H
Capture/Compare/PWM Register 1 (MSB)
CCP1CON
P1M1
P1M0
DC1B1
DC1B0
CCPR2L
Capture/Compare/PWM Register 2 (LSB)
CCPR2H
Capture/Compare/PWM Register 2 (MSB)
CCP2CON
Legend:
—
—
DC2B1
DC2B0
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCP1M3
CCP1M2
CCP1M1
CCP1M0 0000 0000 0000 0000
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCP2M3
CCP2M2
CCP2M1
CCP2M0 --00 0000 --00 0000
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by PWM and Timer2.
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16.0
ENHANCED CAPTURE/
COMPARE/PWM (ECCP)
MODULE
The control register for CCP1 is shown in Register 16-1.
In addition to the expanded functions of the
CCP1CON register, the CCP1 module has two
additional registers associated with enhanced PWM
operation and auto-shutdown features:
The CCP1 module is implemented as a standard CCP
module with enhanced PWM capabilities. These capabilities allow for 2 or 4 output channels, user selectable
polarity, dead-band control, and automatic shutdown
and restart and are discussed in detail in Section 16.2
“Enhanced PWM Mode”.
REGISTER 16-1:
• ECCP1DEL
• ECCP1AS
CCP1CON REGISTER
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
P1M1:P1M0: Enhanced PWM Output Configuration bits
If CCP1M = 00, 01, 10:
xx = P1A assigned as capture/compare input; P1B, P1C, P1D assigned as port pins
If CCP1M = 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
DC1B1:DC1B0: PWM Duty Cycle bit 1 and bit 0
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the 10-bit PWM duty cycle. The eight MSbs of the duty cycle are
found in CCPR1L.
bit 3-0
CCP1M3:CCP1M0: Enhanced CCP Mode Select bits
0000 = Capture/Compare/PWM off (resets CCP1 module)
0001 = Reserved
0010 = Compare mode, toggle output on match
0011 = Capture mode, CAN message time-stamp
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, initialize CCP pin low, on compare match, force CCP pin high
1001 = Compare mode, initialize CCP pin high, on compare match, force CCP pin low
1010 = Compare mode, generate software interrupt only, CCP pin is unaffected
1011 = Compare mode, trigger special event, resets TMR1 or TMR3
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
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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16.1
ECCP Outputs
To configure I/O pins as PWM outputs, the proper PWM
mode must be selected by setting the P1Mx and
CCP1Mx bits (CCP1CON and , respectively). The appropriate TRIS direction bits for the port
pins must also be set as outputs.
The enhanced CCP module may have up to four
outputs depending on the selected operating mode.
These outputs, designated P1A through P1D, are
multiplexed with I/O pins RC2, RE6, RE5 and RG4.
The pin assignments are summarized in Table 16-1.
TABLE 16-1:
PIN ASSIGNMENTS FOR VARIOUS ECCP MODES
CCP1CON
Configuration
RC2
RE6
RE5
RG4
Compatible CCP
00xx11xx
CCP1
RE6
RE5
RG4
Dual PWM
10xx11xx
P1A
P1B(2)
RE5
RG4
Quad PWM
x1xx11xx
P1A
P1B(2)
P1C(2)
P1D
ECCP Mode
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: On PIC18F8X8X devices, these pins can be alternately multiplexed with RH7 or RH6 by changing the
ECCPMX configuration bit.
FIGURE 16-1:
COMPARE MODE OPERATION BLOCK DIAGRAM
Special Event Trigger will:
Reset Timer1 or Timer3, but will not set Timer1 or Timer3 interrupt flag bit
and set bit GO/DONE (ADCON0) which starts an A/D conversion.
Set Flag bit CCP1IF
CCPR1H CCPR1L
Q
RB3/CCP1/P1A pin
S
R
Output
Logic
TRISB
Output Enable
CCP1CON
Mode Select
Comparator
Match
T3CCP2
TMR1H
DS30491D-page 176
TMR1L
0
1
TMR3H
TMR3L
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16.2
Enhanced PWM Mode
The Enhanced PWM mode provides additional PWM
output options for a broader range of control applications. The module is a backward compatible version of
the standard CCP module and offers up to four outputs,
designated P1A through P1D. Users are also able to
select the polarity of the signal (either active-high or
active-low). The module’s output mode and polarity are
configured by setting the P1M1:P1M0 and
CCP1M3:CCP1M0 bits of the CCP1CON register
(CCP1CON and CCP1CON, respectively).
Figure 16-2 shows a simplified block diagram of PWM
operation. 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, ECCP1DEL, which is loaded at
either the duty cycle boundary or the boundary period
(whichever comes first). Because of the buffering, the
module waits until the assigned 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).
16.2.2
PWM DUTY CYCLE
The PWM duty cycle is specified by writing to the
CCPR1L register and to the CCP1CON bits. Up
to 10-bit resolution is available. The CCPR1L contains
the eight MSbs and the CCP1CON contains the
two LSbs. This 10-bit value is represented by
CCPR1L:CCP1CON. The PWM duty cycle is
calculated by the following equation.
EQUATION 16-2:
PWM Duty Cycle = (CCPR1L:CCP1CON) •
TOSC • (TMR2 Prescale Value)
CCPR1L and CCP1CON can be written to at any
time, but the duty cycle value is not copied into
CCPR1H until a match between PR2 and TMR2 occurs
(i.e., the period is complete). In PWM mode, CCPR1H
is a read-only register.
As before, the user must manually configure the
appropriate TRIS bits for output.
The CCPR1H register and a 2-bit internal latch are
used to double-buffer the PWM duty cycle. This
double-buffering is essential for glitchless PWM operation. When the CCPR1H and 2-bit latch match TMR2,
concatenated with an internal 2-bit Q clock or two bits
of the TMR2 prescaler, the CCP1 pin is cleared. The
maximum PWM resolution (bits) for a given PWM
frequency is given by the following equation:
16.2.1
EQUATION 16-3:
PWM PERIOD
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following equation.
PWM Resolution (max) =
log FOSC
FPWM
log(2)
bits
EQUATION 16-1:
PWM Period = [(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
PWM frequency is defined as 1/[PWM period]. When
TMR2 is equal to PR2, the following three events occur
on the next increment cycle:
• TMR2 is cleared
• The CCP1 pin is set (if PWM duty cycle = 0%, the
CCP1 pin will not be set)
• The PWM duty cycle is copied from CCPR1L into
CCPR1H
Note:
The Timer2 postscaler (see Section 13.0
“Timer2 Module”) 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.
2003-2013 Microchip Technology Inc.
Note:
16.2.3
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
PWM OUTPUT CONFIGURATIONS
The P1M1:P1M0 bits in the CCP1CON register allow
one of four configurations:
•
•
•
•
Single Output
Half-Bridge Output
Full-Bridge Output, Forward mode
Full-Bridge Output, Reverse mode
The Single Output mode is the standard PWM mode
discussed in Section 16.2 “Enhanced PWM Mode”.
The Half-Bridge and Full-Bridge Output modes are
covered in detail in the sections that follow.
The general relationship of the outputs in all
configurations is summarized in Figure 16-3.
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TABLE 16-2:
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
PWM Frequency
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
FIGURE 16-2:
2.44 kHz
9.77 kHz
39.06 kHz
156.25 kHz
312.50 kHz
16
4
1
1
1
416.67 kHz
1
FFh
FFh
FFh
3Fh
1Fh
17h
10
10
10
8
7
6.58
SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODULE
CCP1CON
Duty Cycle Registers
CCP1M
4
P1M1
2
CCPR1L
CCP1/P1A
RC2/CCP1/P1A
TRISC
CCPR1H (Slave)
RE6/AD14/P1B or RH7(2)
P1B
R
Comparator
Output
Controller
Q
TRISE
RE5/AD13/P1C or RH6(2)
P1C
TMR2
(Note 1)
TRISE
S
P1D
Comparator
Clear Timer,
set CCP1 pin and
latch D.C.
PR2
Note
1:
2:
CCP1DEL
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.
Alternate setting controlled by the ECCPMX bit (PIC18F8X8X devices only).
FIGURE 16-3:
PWM OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE)
0
CCP1CON
00
RG4/P1D
TRISG
(Single Output)
PR2 + 1
Duty
Cycle
SIGNAL
Period
P1A Modulated
Delay(1)
Delay(1)
P1A Modulated
10
(Half-Bridge)
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
Note 1:
Dead-band delay is programmed using the ECCP1DEL register (Section 16.2.6 “Programmable Dead-Band Delay”).
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FIGURE 16-4:
PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
0
CCP1CON
00
(Single Output)
PR2 + 1
Duty
Cycle
SIGNAL
Period
P1A Modulated
P1A Modulated
10
(Half-Bridge)
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
Note 1: Dead-band delay is programmed using the ECCP1DEL register (Section 16.2.6 “Programmable Dead-Band Delay”).
Relationships:
• Period = 4 * TOSC * (PR2 + 1) * (TMR2 prescale value)
• Duty Cycle = TOSC * (CCPR1L:CCP1CON) * (TMR2 prescale value)
• Delay = 4 * TOSC * (PWM1CON)
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16.2.4
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 P1A pin while the complementary PWM
output signal is output on the P1B pin (Figure 16-5).
This mode can be used for half-bridge applications, as
shown in Figure 16-6, or for full-bridge applications
where four power switches are being modulated with
two PWM signals.
Since the P1A and P1B outputs are multiplexed with
the PORTC and PORTE data latches, the
TRISC and TRISE bits must be cleared to
configure P1A and P1B as outputs.
FIGURE 16-5:
HALF-BRIDGE PWM
OUTPUT
Period
Period
Duty Cycle
In Half-Bridge Output mode, the programmable deadband delay can be used to prevent shoot-through
current in half-bridge power devices. The value of bits
PDC6:PDC0 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 16.2.6
“Programmable Dead-Band Delay” for more details
of the dead-band delay operations.
P1A (2)
td
td
P1B (2)
(1)
(1)
(1)
td = Dead-band Delay
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
FIGURE 16-6:
EXAMPLES OF HALF-BRIDGE OUTPUT MODE APPLICATIONS
V+
Standard Half-Bridge Circuit (“Push-Pull”)
PIC18FXX80/XX85
FET
Driver
+
V
-
P1A
Load
FET
Driver
+
V
-
P1B
V-
Half-Bridge Output Driving a Full-Bridge Circuit
V+
PIC18FXX80/XX85
FET
Driver
FET
Driver
P1A
FET
Driver
Load
FET
Driver
P1B
V-
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16.2.5
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 P1A is continuously active
and pin P1D is modulated. In the Reverse mode, pin
PGC is continuously active and pin P1B is modulated.
These are illustrated in Figure 16-7.
FIGURE 16-7:
P1A, P1B, P1C and P1D outputs are multiplexed with
the PORTC, PORTE and PORTG data
latches. The TRISC, TRISC and TRISG
bits must be cleared to make the P1A, P1B, P1C and
P1D pins outputs.
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)
(1)
Note 1: At this time, the TMR2 register is equal to the PR2 register.
Note 2: Output signal is shown as active-high.
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FIGURE 16-8:
EXAMPLE OF FULL-BRIDGE APPLICATION
V+
PIC18FXX80/XX85
FET
Driver
QC
QA
FET
Driver
P1A
Load
P1B
FET
Driver
P1C
FET
Driver
QD
QB
VP1D
16.2.5.1
Direction Change in Full-Bridge Mode
In the Full-Bridge Output mode, the P1M1 bit in the
CCP1CON register allows the 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 bit (T2CON). 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 16-9.
Note that in the Full-Bridge Output mode, the CCP1
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.
Figure 16-10 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 16-8) 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 for a 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.
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.
DS30491D-page 182
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FIGURE 16-9:
PWM DIRECTION CHANGE
Period(1)
SIGNAL
Period
P1A (Active-High)
P1B (Active-High)
DC
P1C (Active-High)
(Note 2)
P1D (Active-High)
DC
Note 1:
2:
The direction bit in the CCP1 Control register (CCP1CON) 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 16-10:
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
t = tOFF – tON
Note 1: 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.
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16.2.6
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 (shootthrough 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 16-5 for an illustration. The lower seven bits
of the ECCP1DEL register (Register 16-2) set the
delay period in terms of microcontroller instruction
cycles (TCY or 4 TOSC).
16.2.7
ENHANCED PWM
AUTO-SHUTDOWN
When the CCP1 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.
REGISTER 16-2:
A shutdown event can be caused by either of the two
comparator modules or a low level on the RB0 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
low digital signal on the RB0 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 ECCPAS2:ECCPAS0 bits (bits of the
ECCP1AS register).
When a shutdown occurs, the output pins are asynchronously placed in their shutdown states, specified
by the PSSAC1:PSSAC0 and PSSBD1:PSSBD0 bits
(ECCP1AS). 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 (ECCP1AS) 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 automatic restarts are not enabled, the
ECCPASE bit is cleared by firmware when the cause of
the shutdown clears. If automatic restarts are enabled,
the ECCPASE bit is automatically cleared when the
cause of the auto-shutdown has cleared.
If the ECCPASE bit is set when a PWM period begins,
the PWM outputs remain in their shutdown state for that
entire PWM period. When the ECCPASE bit is cleared,
the PWM outputs will return to normal operation at the
beginning of the next PWM period.
Note:
Writing to the ECCPASE bit is disabled
while a shutdown condition is active.
ECCP1DEL: ECCP1 DELAY REGISTER
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 0
bit 7
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
bit 6-0
PDC: PWM Delay Count bits
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.
Legend:
DS30491D-page 184
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
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REGISTER 16-3:
ECCP1AS: ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN
CONTROL REGISTER
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 0
bit 7
ECCPASE: ECCP Auto-Shutdown Event Status bit
0 = ECCP outputs are operating
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
bit 6-4
ECCPAS: ECCP Auto-Shutdown Source Select bits
000 = Auto-shutdown is disabled
001 = Comparator 1 output
010 = Comparator 2 output
011 = Either Comparator 1 or 2
100 = RB0
101 = RB0 or Comparator 1
110 = RB0 or Comparator 2
111 = RB0 or Comparator 1 or Comparator 2
bit 3-2
PSSACn: Pins A and C Shutdown State Control bits
00 = Drive pins A and C to ‘0’
01 = Drive pins A and C to ‘1’
1x = Pins A and C tri-state
bit 1-0
PSSBDn: Pins B and D Shutdown State Control bits
00 = Drive pins B and D to ‘0’
01 = Drive pins B and D to ‘1’
1x = Pins B and D tri-state
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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16.2.7.1
Auto-Shutdown and Automatic
Restart
16.2.8
The auto-shutdown feature can be configured to allow
automatic restarts of the module following a shutdown
event. This is enabled by setting the PRSEN bit of the
ECCP1DEL register (ECCP1DEL).
In Shutdown mode with PRSEN = 1 (Figure 16-11), 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 16-12), 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, if the autoshutdown source is one of the comparators, 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 16-11:
START-UP CONSIDERATIONS
When the ECCP module is used in the PWM mode, the
application hardware must use the proper external pullup 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 CCP1M1:CCP1M0 bits (CCP1CON) 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 16-12:
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
DS30491D-page 186
ECCPASE
Cleared by
Shutdown
Shutdown Firmware PWM
Event Occurs Event Clears
Resumes
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16.2.9
SETUP FOR PWM OPERATION
7.
The following steps should be taken when configuring
the ECCP1 module for PWM operation:
1.
8.
Configure the PWM pins, P1A and P1B (and
P1C and P1D, if used), as inputs by setting the
corresponding TRISB bits.
Set the PWM period by loading the PR2 register.
Configure the ECCP1 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
P1M1:P1M0 bits.
• Select the polarities of the PWM output
signals with the CCP1M3:CCP1M0 bits.
Set the PWM duty cycle by loading the CCPR1L
register and CCP1CON bits.
For Half-Bridge Output mode, set the deadband delay by loading ECCP1DEL with
the appropriate value.
If auto-shutdown operation is required, load the
ECCPAS register:
• Select the auto-shutdown sources using the
ECCPAS bits.
• Select the shutdown states of the PWM
output pins using PSSAC1:PSSAC0 and
PSSBD1:PSSBD0 bits.
• Set the ECCPASE bit (ECCPAS).
• Configure the comparators using the CMCON
register.
• Configure the comparator inputs as analog
inputs.
2.
3.
4.
5.
6.
TABLE 16-3:
Name
9.
If auto-restart operation is required, set the
PRSEN bit (ECCP1DEL).
Configure and start TMR2:
• Clear the TMR2 interrupt flag bit by clearing
the TMR2IF bit (PIR1).
• Set the TMR2 prescale value by loading the
T2CKPS bits (T2CON).
• Enable Timer2 by setting the TMR2ON bit
(T2CON).
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 TRISB
bits.
• Clear the ECCPASE bit (ECCP1AS).
16.2.10
EFFECTS OF A RESET
Both Power-on and subsequent Resets will force all
ports to Input mode and the CCP registers to their
Reset states.
This forces the Enhanced CCP module to reset to a
state compatible with the standard CCP module.
REGISTERS ASSOCIATED WITH PWM AND TIMER2
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Value on
all other
Resets
Bit 0
Value on
POR, BOR
0000 000x 0000 000u
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000 0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000 0000 0000
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111 1111 1111
INTCON
IPR1
GIE/GIEH PEIE/GIEL
TRISC
PORTC Data Direction Register
TRISE
PORTE Data Direction Register
TRISG
—
—
—
1111 1111 1111 1111
1111 1111 1111 1111
PORTG Data Direction Register
---1 1111 ---1 1111
TMR2
Timer2 Module Register
0000 0000 0000 0000
PR2
Timer2 Module Period Register
1111 1111 1111 1111
T2CON
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
CCPR1L
Capture/Compare/PWM Register 1 (LSB)
CCPR1H
Capture/Compare/PWM Register 1 (MSB)
CCP1CON
ECCP1AS
ECCP1DEL
Legend:
P1M1
P1M0
DC1B1
DC1B0
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0
PRSEN
PDC6
PDC5
PDC4
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCP1M3
CCP1M2
CCP1M1
CCP1M0 0000 0000 0000 0000
PSSAC1
PSSAC0
PSSBD1
PSSBD0
0000 0000 0000 0000
PDC3
PDC2
PDC1
PDC0
0000 0000 uuuu uuuu
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by PWM and Timer2.
2003-2013 Microchip Technology Inc.
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NOTES:
DS30491D-page 188
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17.0
17.1
MASTER SYNCHRONOUS
SERIAL PORT (MSSP)
MODULE
Master SSP (MSSP) Module
Overview
The Master Synchronous Serial Port (MSSP) module is
a serial interface, useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers, display drivers, A/D converters, etc. The MSSP module
can operate in one of two modes:
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit (I2C)
- Full Master mode
- Slave mode (with general address call)
17.3
SPI Mode
The SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. All four
modes of SPI are supported. To accomplish
communication, typically three pins are used:
• Serial Data Out (SDO) – RC5/SDO
• Serial Data In (SDI) – RC4/SDI/SDA
• Serial Clock (SCK) – RC3/SCK/SCL
Additionally, a fourth pin may be used when in a Slave
mode of operation:
• Slave Select (SS) – RF7/SS
Figure 17-1 shows the block diagram of the MSSP
module when operating in SPI mode.
FIGURE 17-1:
MSSP BLOCK DIAGRAM
(SPI MODE)
The I2C interface supports the following modes in
hardware:
Internal
Data Bus
Read
• Master mode
• Multi-Master mode
• Slave mode
17.2
Control Registers
The MSSP module has three associated registers.
These include a status register (SSPSTAT) and two
control registers (SSPCON1 and SSPCON2). The use
of these registers and their individual configuration bits
differ significantly depending on whether the MSSP
module is operated in SPI or I2C mode.
Additional details are provided under the individual
sections.
Write
SSPBUF Reg
RC4/SDI/SDA
SSPSR Reg
Shift
Clock
RC5/SDO
bit0
RF7/SS
SS Control
Enable
Edge
Select
2
Clock Select
RC3/SCK/
SCL
SSPM3:SSPM0
SMP:CKE 4
TMR2 Output
2
2
Edge
Select
Prescaler TOSC
4, 16, 64
(
)
Data to TX/RX in SSPSR
TRIS bit
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17.3.1
REGISTERS
The MSSP module has four registers for SPI mode
operation. These are:
SSPSR is the shift register used for shifting data in or
out. SSPBUF is the buffer register to which data bytes
are written to or read from.
In receive operations, SSPSR and SSPBUF together
create a double-buffered receiver. When SSPSR
receives a complete byte, it is transferred to SSPBUF
and the SSPIF interrupt is set.
• MSSP Control Register 1 (SSPCON1)
• MSSP Status Register (SSPSTAT)
• Serial Receive/Transmit Buffer Register
(SSPBUF)
• MSSP Shift Register (SSPSR) – Not directly
accessible
During transmission, the SSPBUF is not doublebuffered. A write to SSPBUF will write to both SSPBUF
and SSPSR.
SSPCON1 and SSPSTAT are the control and status
registers in SPI mode operation. The SSPCON1 register is readable and writable. The lower 6 bits of the
SSPSTAT are read-only. The upper two bits of the
SSPSTAT are read/write.
REGISTER 17-1:
SSPSTAT: MSSP STATUS REGISTER (SPI MODE)
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: Sample bit
SPI Master mode:
1 = Input data sampled at end of data output time
0 = Input data sampled at middle of data output time
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode.
bit 6
CKE: SPI Clock Edge Select bit
When CKP = 0:
1 = Data transmitted on rising edge of SCK
0 = Data transmitted on falling edge of SCK
When CKP = 1:
1 = Data transmitted on falling edge of SCK
0 = Data transmitted on rising edge of SCK
bit 5
D/A: Data/Address bit
Used in I2C mode only.
bit 4
P: Stop bit
Used in I2C mode only. This bit is cleared when the MSSP module is disabled, SSPEN is
cleared.
bit 3
S: Start bit
Used in I2C mode only.
bit 2
R/W: Read/Write bit Information
Used in I2C mode only.
bit 1
UA: Update Address bit
Used in I2C mode only.
bit 0
BF: Buffer Full Status bit (Receive mode only)
1 = Receive complete, SSPBUF is full
0 = Receive not complete, SSPBUF is empty
Legend:
DS30491D-page 190
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
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REGISTER 17-2:
SSPCON1: MSSP CONTROL REGISTER 1 (SPI MODE)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
bit 7
bit 0
bit 7
WCOL: Write Collision Detect bit (Transmit mode only)
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
SPI Slave 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 (must be
cleared in software).
0 = No overflow
Note:
bit 5
In Master mode, the overflow bit is not set since each new reception (and
transmission) is initiated by writing to the SSPBUF register.
SSPEN: Synchronous Serial Port Enable bit
1 = Enables serial port and configures SCK, SDO, SDI, and SS as serial port pins
0 = Disables serial port and configures these pins as I/O port pins
Note:
When enabled, these pins must be properly configured as input or output.
bit 4
CKP: Clock Polarity Select bit
1 = Idle state for clock is a high level
0 = Idle state for clock is a low level
bit 3-0
SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
0101 = SPI Slave mode, clock = SCK pin, SS pin control disabled, SS can be used as I/O pin
0100 = SPI Slave mode, clock = SCK pin, SS pin control enabled
0011 = SPI Master mode, clock = TMR2 output/2
0010 = SPI Master mode, clock = FOSC/64
0001 = SPI Master mode, clock = FOSC/16
0000 = SPI Master mode, clock = FOSC/4
Note:
Bit combinations not specifically listed here are either reserved or implemented in
I2C mode 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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17.3.2
OPERATION
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSPCON1 and SSPSTAT).
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 MSSP 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 8 bits
of data have been received, that byte is moved to the
SSPBUF register. Then the Buffer Full detect bit, BF
(SSPSTAT) and the interrupt flag bit, SSPIF, are
set. This double-buffering of the received data
(SSPBUF) allows the next byte to start reception before
EXAMPLE 17-1:
LOOP
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
(SSPCON1), 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.
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), 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 MSSP 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 17-1 shows the loading of the
SSPBUF (SSPSR) for data transmission.
The SSPSR is not directly readable or writable and can
only be accessed by addressing the SSPBUF register.
Additionally, the MSSP Status register (SSPSTAT)
indicates the various status conditions.
LOADING THE SSPBUF (SSPSR) REGISTER
BTFSS
BRA
MOVF
SSPSTAT, BF
LOOP
SSPBUF, W
;Has data been received(transmit complete)?
;No
;WREG reg = contents of SSPBUF
MOVWF
RXDATA
;Save in user RAM, if data is meaningful
MOVF
MOVWF
TXDATA, W
SSPBUF
;W reg = contents of TXDATA
;New data to xmit
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17.3.3
ENABLING SPI I/O
17.3.4
To enable the serial port, SSP Enable bit, SSPEN
(SSPCON1), must be set. To reset or reconfigure
SPI mode, clear the SSPEN bit, reinitialize 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
TRIS register) appropriately programmed as follows:
• SDI is automatically controlled by the SPI module
• SDO must have TRISC bit cleared
• SCK (Master mode) must have TRISC bit
cleared
• SCK (Slave mode) must have TRISC bit set
• SS must have TRISF bit set
TYPICAL CONNECTION
Figure 17-2 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 (TRIS) register to the opposite value.
FIGURE 17-2:
SPI MASTER/SLAVE CONNECTION
SPI Master SSPM3:SSPM0 = 00xxb
SPI Slave SSPM3:SSPM0 = 010xb
SDO
SDI
Serial Input Buffer
(SSPBUF)
SDI
Shift Register
(SSPSR)
MSb
Serial Input Buffer
(SSPBUF)
SDO
LSb
Shift Register
(SSPSR)
MSb
LSb
Serial Clock
SCK
PROCESSOR 1
2003-2013 Microchip Technology Inc.
SCK
PROCESSOR 2
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17.3.5
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 17-2) 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.
The clock polarity is selected by appropriately programming the CKP bit (SSPCON1). This then, would
give waveforms for SPI communication, as shown in
FIGURE 17-3:
Figure 17-3, Figure 17-5 and Figure 17-6, 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
10.00 Mbps.
Figure 17-3 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 7
bit 0
Input
Sample
(SMP = 1)
SSPIF
SSPSR to
SSPBUF
DS30491D-page 194
Next Q4 Cycle
after Q2
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17.3.6
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.
the SS pin goes high, the SDO pin is no longer driven
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.
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.
Note 1: When the SPI is in Slave mode with SS pin
control enabled (SSPCON = 0100),
the SPI module will reset if the SS pin is set
to VDD.
While in Sleep mode, the slave can transmit/receive
data. When a byte is received, the device will wake-up
from Sleep.
2: If the SPI is used in Slave mode with CKE
set, then the SS pin control must be
enabled.
17.3.7
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.
SLAVE SELECT
SYNCHRONIZATION
The SS pin allows a Synchronous Slave mode. The SPI
must be in Slave mode with SS pin control enabled
(SSPCON1 = 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
FIGURE 17-4:
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
2003-2013 Microchip Technology Inc.
Next Q4 Cycle
after Q2
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FIGURE 17-5:
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 17-6:
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 7
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
bit 0
Input
Sample
(SMP = 0)
SSPIF
Interrupt
Flag
SSPSR to
SSPBUF
DS30491D-page 196
Next Q4 Cycle
after Q2
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17.3.8
SLEEP OPERATION
17.3.10
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 17-1 shows the compatibility between the
standard SPI modes and the states of the CKP and
CKE control bits.
TABLE 17-1:
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 MSSP interrupt
flag bit will be set and if enabled, will wake the device
from Sleep.
17.3.9
Control Bits State
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 MSSP module and terminates the
current transfer.
Name
SPI BUS MODES
Standard SPI Mode
Terminology
EFFECTS OF A RESET
TABLE 17-2:
BUS MODE COMPATIBILITY
REGISTERS ASSOCIATED WITH SPI OPERATION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
all other
Resets
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF 0000 0000 0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE 0000 0000 0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP 1111 1111 1111 1111
TRISF4
TRISF3
TRISF2
TRISF1
TRISF0 1111 1111 uuuu uuuu
INTCON
TRISC
TRISF
SSPBUF
GIE/GIEH PEIE/GIEL
RBIF
Value on
POR, BOR
PORTC Data Direction Register
TRISF7
TRISF6
TRISF5
0000 0000 0000 0000
1111 1111 1111 1111
Synchronous Serial Port Receive Buffer/Transmit Register
xxxx xxxx uuuu uuuu
SSPCON
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
0000 0000 0000 0000
SSPSTAT
SMP
CKE
D/A
P
S
R/W
UA
BF
0000 0000 0000 0000
Legend:
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the MSSP in SPI mode.
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17.4
I2C Mode
17.4.1
2
The MSSP module in I C mode fully implements all
master and slave functions (including general call support) and provides interrupts on Start and Stop bits in
hardware to determine a free bus (multi-master function). The MSSP module implements the standard
mode specifications, as well as 7-bit and 10-bit
addressing.
Two pins are used for data transfer:
• Serial clock (SCL) – RC3/SCK/SCL
• Serial data (SDA) – RC4/SDI/SDA
The user must configure these pins as inputs or outputs
through the TRISC bits.
FIGURE 17-7:
MSSP BLOCK DIAGRAM
(I2C MODE)
Internal
Data Bus
Read
Write
RC3/SCK/
SCL
Shift
Clock
LSb
Match Detect
Addr Match
SSPADD Reg
Start and
Stop bit Detect
DS30491D-page 198
•
•
•
•
•
MSSP Control Register 1 (SSPCON1)
MSSP Control Register 2 (SSPCON2)
MSSP Status Register (SSPSTAT)
Serial Receive/Transmit Buffer (SSPBUF)
MSSP Shift Register (SSPSR) – Not directly
accessible
• MSSP Address Register (SSPADD)
SSPCON, SSPCON2 and SSPSTAT are the control
and status registers in I2C mode operation. The
SSPCON and SSPCON2 registers are readable and
writable. The lower six bits of the SSPSTAT are readonly. The upper two bits of the SSPSTAT are
read/write.
SSPSR is the shift register used for shifting data in or
out. SSPBUF is the buffer register to which data bytes
are written to or read from.
In receive operations, SSPSR and SSPBUF together
create a double-buffered receiver. When SSPSR
receives a complete byte, it is transferred to SSPBUF
and the SSPIF interrupt is set.
SSPSR Reg
MSb
The MSSP module has six registers for I2C operation.
These are:
SSPADD register holds the slave device address when
the SSP is configured in I2C Slave mode. When the
SSP is configured in Master mode, the lower seven bits
of SSPADD act as the Baud Rate Generator reload
value.
SSPBUF Reg
RC4/
SDI/
SDA
REGISTERS
During transmission, the SSPBUF is not doublebuffered. A write to SSPBUF will write to both SSPBUF
and SSPSR.
Set, Reset
S, P bits
(SSPSTAT Reg)
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REGISTER 17-3:
SSPSTAT: MSSP STATUS REGISTER (I2C MODE)
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: Slew Rate Control bit
In Master or Slave mode:
1 = Slew rate control disabled for Standard Speed mode (100 kHz and 1 MHz)
0 = Slew rate control enabled for High-Speed mode (400 kHz)
bit 6
CKE: SMBus Select bit
In Master or Slave mode:
1 = Enable SMBus specific inputs
0 = Disable SMBus specific inputs
bit 5
D/A: Data/Address bit
In Master mode:
Reserved.
In Slave mode:
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
1 = Indicates that a Stop bit has been detected last
0 = Stop bit was not detected last
bit 3
S: Start bit
1 = Indicates that a Start bit has been detected last
0 = Start bit was not detected last
bit 2
R/W: Read/Write bit Information (I2C mode only)
In Slave mode:
1 = Read
0 = Write
Note:
Note:
Note:
This bit is cleared on Reset and when SSPEN is cleared.
This bit is cleared on Reset and when SSPEN is cleared.
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 not ACK bit.
In Master mode:
1 = Transmit is in progress
0 = Transmit is not in progress
Note:
ORing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSP is
in Idle mode.
bit 1
UA: Update Address bit (10-bit Slave 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
In Transmit mode:
1 = Receive complete, SSPBUF is full
0 = Receive not complete, SSPBUF is empty
In Receive mode:
1 = Data transmit in progress (does not include the ACK and Stop bits), SSPBUF is full
0 = Data transmit complete (does not include the ACK and Stop bits), SSPBUF is empty
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
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x = Bit is unknown
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REGISTER 17-4:
SSPCON1: MSSP CONTROL REGISTER 1 (I2C MODE)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
WCOL
SSPOV
SSPEN
CKP
SSPM3
SSPM2
SSPM1
SSPM0
bit 7
bit 0
bit 7
WCOL: Write Collision Detect bit
In Master Transmit mode:
1 = A write to the SSPBUF register was attempted while the I2C conditions were not valid for
a transmission to be started (must be cleared in software)
0 = No collision
In Slave Transmit mode:
1 = The SSPBUF register is written while it is still transmitting the previous word (must be
cleared in software)
0 = No collision
In Receive mode (Master or Slave modes):
This is a “don’t care” bit.
bit 6
SSPOV: Receive Overflow Indicator bit
In Receive mode:
1 = A byte is received while the SSPBUF register is still holding the previous byte (must be
cleared in software)
0 = No overflow
In Transmit mode:
This is a “don’t care” bit in Transmit mode.
bit 5
SSPEN: Synchronous Serial Port Enable bit
1 = Enables the serial port and configures the SDA and SCL pins as the serial port pins
0 = Disables serial port and configures these pins as I/O port pins
Note:
When enabled, the SDA and SCL pins must be properly configured as input or
output.
bit 4
CKP: SCK Release Control bit
In Slave mode:
1 = Release clock
0 = Holds clock low (clock stretch), used to ensure data setup time
In Master mode:
Unused in this mode.
bit 3-0
SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
1111 = I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled
1110 = I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled
1011 = I2C Firmware Controlled Master mode (slave Idle)
1000 = I2C Master mode, clock = FOSC/(4 * (SSPADD + 1))
0111 = I2C Slave mode, 10-bit address
0110 = I2C Slave mode, 7-bit address
Note:
Bit combinations not specifically listed here are either reserved or implemented in
SPI mode only.
Legend:
DS30491D-page 200
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
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REGISTER 17-5:
SSPCON2: MSSP CONTROL REGISTER 2 (I2C MODE)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
GCEN
ACKSTAT
ACKDT
ACKEN
RCEN
PEN
RSEN
SEN
bit 7
bit 0
bit 7
GCEN: General Call Enable bit (Slave mode only)
1 = Enable interrupt when a general call address (0000h) is received in the SSPSR
0 = General call address disabled
bit 6
ACKSTAT: Acknowledge Status bit (Master Transmit mode only)
1 = Acknowledge was not received from slave
0 = Acknowledge was received from slave
bit 5
ACKDT: Acknowledge Data bit (Master Receive mode only)
1 = Not Acknowledge
0 = Acknowledge
Note:
Value that will be transmitted when the user initiates an Acknowledge sequence at
the end of a receive.
bit 4
ACKEN: Acknowledge Sequence Enable bit (Master Receive mode only)
1 = Initiate Acknowledge sequence on SDA and SCL pins and transmit ACKDT data bit.
Automatically cleared by hardware.
0 = Acknowledge sequence Idle
bit 3
RCEN: Receive Enable bit (Master Mode only)
1 = Enables Receive mode for I2C
0 = Receive Idle
bit 2
PEN: Stop Condition Enable bit (Master mode only)
1 = Initiate Stop condition on SDA and SCL pins. Automatically cleared by hardware.
0 = Stop condition Idle
bit 1
RSEN: Repeated Start Condition Enabled bit (Master mode only)
1 = Initiate Repeated Start condition on SDA and SCL pins. Automatically cleared by hardware.
0 = Repeated Start condition Idle
bit 0
SEN: Start Condition Enabled/Stretch Enabled bit
In Master mode:
1 = Initiate Start condition on SDA and SCL pins. Automatically cleared by hardware.
0 = Start condition Idle
In Slave mode:
1 = Clock stretching is enabled for both slave transmit and slave receive (stretch enabled)
0 = Clock stretching is disabled
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
Note:
x = Bit is unknown
For bits ACKEN, RCEN, PEN, RSEN, SEN: If the I2C module is not in the Idle mode,
this bit may not be set (no spooling) and the SSPBUF may not be written (or writes
to the SSPBUF are disabled).
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17.4.2
OPERATION
The MSSP module functions are enabled by setting
MSSP Enable bit, SSPEN (SSPCON).
The SSPCON1 register allows control of the I 2C operation. Four mode selection bits (SSPCON) allow
one of the following I 2C modes to be selected:
I2C Master mode, clock = OSC/4 (SSPADD + 1)
I 2C Slave mode (7-bit address)
I 2C Slave mode (10-bit address)
I 2C Slave mode (7-bit address) with Start and
Stop bit interrupts enabled
• I 2C Slave mode (10-bit address) with Start and
Stop bit interrupts enabled
• I 2C Firmware Controlled Master mode, slave is
Idle
•
•
•
•
Selection of any I 2C 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 TRISC bits. To ensure proper operation
of the module, pull-up resistors must be provided
externally to the SCL and SDA pins.
17.4.3
SLAVE MODE
In Slave mode, the SCL and SDA pins must be configured as inputs (TRISC set). The MSSP module
will override the input state with the output data when
required (slave-transmitter).
The I 2C Slave mode hardware will always generate an
interrupt on an address match. Through the mode
select bits, the user can also choose to interrupt on
Start and Stop bits
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
load the SSPBUF register with the received value
currently in the SSPSR register.
17.4.3.1
Once the MSSP 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 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:
1.
2.
3.
4.
In this case, the SSPSR register value is not loaded
into the SSPBUF but bit SSPIF (PIR1) is set. The
BF bit is cleared by reading the SSPBUF register while
bit SSPOV is cleared through software.
The SSPSR register value is loaded into the
SSPBUF register.
The buffer full bit BF is set.
An ACK pulse is generated.
MSSP interrupt flag bit, SSPIF (PIR1), 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. The five Most Significant bits
(MSbs) of the first address byte specify if this is a 10-bit
address. Bit R/W (SSPSTAT) must specify a write
so the slave device will receive the second address
byte. For a 10-bit address, the first byte would equal
‘11110 A9 A8 0’, where ‘A9’ and ‘A8’ are the two
MSbs of the address. The sequence of events for
10-bit address is as follows, with steps 7 through 9 for
the slave-transmitter:
1.
2.
3.
4.
5.
Any combination of the following conditions will cause
the MSSP module not to give this ACK pulse:
• The buffer full bit BF (SSPSTAT) was set
before the transfer was received.
• The overflow bit SSPOV (SSPCON) was set
before the transfer was received.
Addressing
6.
7.
8.
9.
Receive first (high) byte of address (bits SSPIF,
BF and bit UA (SSPSTAT) 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.
The SCL clock input must have a minimum high and
low for proper operation. The high and low times of the
I2C specification, as well as the requirement of the
MSSP module, are shown in timing parameter #100
and parameter #101.
DS30491D-page 202
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17.4.3.2
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 and the SDA line is held low
(ACK).
When the address byte overflow condition exists, then
the no Acknowledge (ACK) pulse is given. An overflow
condition is defined as either bit BF (SSPSTAT) is
set or bit SSPOV (SSPCON1) is set.
An MSSP interrupt is generated for each data transfer
byte. Flag bit SSPIF (PIR1) must be cleared in software. The SSPSTAT register is used to determine the
status of the byte.
If SEN is enabled (SSPCON2 = 1), RC3/SCK/SCL
will be held low (clock stretch) following each data
transfer. The clock must be released by setting bit
CKP (SSPCON). See Section 17.4.4 “Clock
Stretching” for more detail.
17.4.3.3
Transmission
When the R/W bit of the incoming address byte is set
and an address match occurs, the R/W bit of the
SSPSTAT register is set. The received address is
loaded into the SSPBUF register. The ACK pulse will
be sent on the ninth bit and pin RC3/SCK/SCL is held
low, regardless of SEN (see Section 17.4.4 “Clock
Stretching” for more detail). By stretching the clock,
the master will be unable to assert another clock pulse
until the slave is done preparing the transmit data. The
transmit data must be loaded into the SSPBUF register
which also loads the SSPSR register. Then pin RC3/
SCK/SCL should be enabled by setting bit CKP
(SSPCON1). 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 17-9).
The ACK pulse from the master-receiver is latched on
the rising edge of the ninth SCL input pulse. If the SDA
line is high (not ACK), then the data transfer is complete. In this case, when the ACK is latched by the
slave, the slave logic is reset (resets SSPSTAT register) and the slave monitors for another occurrence of
the Start bit. If the SDA line was low (ACK), the next
transmit data must be loaded into the SSPBUF register.
Again, pin RC3/SCK/SCL must be enabled by setting
bit CKP.
An MSSP interrupt is generated for each data transfer
byte. The SSPIF bit must be cleared in software and
the SSPSTAT register is used to determine the status
of the byte. The SSPIF bit is set on the falling edge of
the ninth clock pulse.
2003-2013 Microchip Technology Inc.
DS30491D-page 203
DS30491D-page 204
CKP
2
A6
3
4
A4
5
A3
Receiving Address
A5
6
A2
(CKP does not reset to ‘0’ when SEN = 0)
SSPOV (SSPCON)
BF (SSPSTAT)
(PIR1)
SSPIF
1
SCL
S
A7
7
A1
8
9
ACK
R/W = 0
1
D7
3
4
D4
5
D3
Receiving Data
D5
Cleared in software
SSPBUF is read
2
D6
6
D2
7
D1
8
D0
9
ACK
1
D7
2
D6
3
4
D4
5
D3
Receiving Data
D5
6
D2
7
D1
8
D0
Bus master
terminates
transfer
P
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
9
ACK
FIGURE 17-8:
SDA
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I2C SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 7-BIT ADDRESS)
2003-2013 Microchip Technology Inc.
2003-2013 Microchip Technology Inc.
1
CKP
2
A6
Data in
sampled
BF (SSPSTAT)
SSPIF (PIR1)
S
A7
3
4
A4
5
A3
6
A2
Receiving Address
A5
7
A1
8
R/W = 1
9
ACK
SCL held low
while CPU
responds to SSPIF
1
D7
4
D4
5
D3
6
D2
Transmitting Data
Cleared in software
3
D5
CKP is set in software
SSPBUF is written in software
2
D6
7
8
D0
9
ACK
From SSPIF ISR
D1
1
D7
4
D4
5
D3
6
D2
CKP is set in software
7
8
D0
9
ACK
From SSPIF ISR
D1
Transmitting Data
Cleared in software
3
D5
SSPBUF is written in software
2
D6
P
FIGURE 17-9:
SCL
SDA
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I2C SLAVE MODE TIMING (TRANSMISSION, 7-BIT ADDRESS)
DS30491D-page 205
DS30491D-page 206
2
1
4
1
5
0
7
UA is set indicating that
the SSPADD needs to be
updated
SSPBUF is written with
contents of SSPSR
6
A9 A8
8
9
(CKP does not reset to ‘0’ when SEN = 0)
UA (SSPSTAT)
SSPOV (SSPCON)
CKP
3
1
Cleared in software
BF (SSPSTAT)
(PIR1)
SSPIF
1
SCL
S
1
ACK
R/W = 0
A7
2
4
A4
5
A3
6
8
9
A0 ACK
UA is set indicating that
SSPADD needs to be
updated
Cleared by hardware
when SSPADD is updated
with low byte of address
7
A2 A1
Cleared in software
3
A5
Dummy read of SSPBUF
to clear BF flag
1
A6
Receive Second Byte of Address
1
D7
4
5
6
Cleared in software
3
7
D1
Cleared by hardware when
SSPADD is updated with high
byte of address
2
D3 D2
Receive Data Byte
D6 D5 D4
Clock is held low until
update of SSPADD has
taken place
8
9
1
2
4
5
6
D2
Cleared in software
3
D3
Receive Data Byte
D0 ACK D7 D6 D5 D4
7
8
D1 D0
9
P
Bus master
terminates
transfer
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
ACK
FIGURE 17-10:
SDA
Receive First Byte of Address
Clock is held low until
update of SSPADD has
taken place
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I2C SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 10-BIT ADDRESS)
2003-2013 Microchip Technology Inc.
2003-2013 Microchip Technology Inc.
2
CKP (SSPCON)
UA (SSPSTAT)
BF (SSPSTAT)
(PIR1)
SSPIF
1
S
SCL
1
4
1
5
0
6
7
A9 A8
8
UA is set indicating that
the SSPADD needs to be
updated
SSPBUF is written with
contents of SSPSR
3
1
Receive First Byte of Address
1
9
ACK
1
3
4
5
Cleared in software
2
7
UA is set indicating that
SSPADD needs to be
updated
Cleared by hardware when
SSPADD is updated with low
byte of address
6
A6 A5 A4 A3 A2 A1
8
A0
Receive Second Byte of Address
Dummy read of SSPBUF
to clear BF flag
A7
9
ACK
2
3
1
4
1
Cleared in software
1
1
5
0
6
8
9
ACK
R/W = 1
1
2
4
5
6
CKP is set in software
9
P
Completion of
data transmission
clears BF flag
8
ACK
Bus master
terminates
transfer
CKP is automatically cleared in hardware, holding SCL low
7
D4 D3 D2 D1 D0
Cleared in software
3
D7 D6 D5
Transmitting Data Byte
Clock is held low until
CKP is set to ‘1’
Write of SSPBUF
BF flag is clear
initiates transmit
at the end of the
third address sequence
7
A9 A8
Cleared by hardware when
SSPADD is updated with high
byte of address.
Dummy read of SSPBUF
to clear BF flag
Sr
1
Receive First Byte of Address
Clock is held low until
update of SSPADD has
taken place
FIGURE 17-11:
SDA
R/W = 0
Clock is held low until
update of SSPADD has
taken place
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17.4.4
CLOCK STRETCHING
Both 7- and 10-bit Slave modes implement automatic
clock stretching during a transmit sequence.
The SEN bit (SSPCON2) allows clock stretching to
be enabled during receives. Setting SEN will cause the
SCL pin to be held low at the end of each data receive
sequence.
17.4.4.1
Clock Stretching for 7-bit Slave
Receive Mode (SEN = 1)
In 7-bit Slave Receive mode, on the falling edge of the
ninth clock at the end of the ACK sequence if the BF bit
is set, the CKP bit in the SSPCON1 register is automatically cleared, forcing the SCL output to be held low.
The CKP being cleared to ‘0’ will assert the SCL line
low. The CKP bit must be set in the user’s ISR before
reception is allowed to continue. By holding the SCL
line low, the user has time to service the ISR and read
the contents of the SSPBUF before the master device
can initiate another receive sequence. This will prevent
buffer overruns from occurring (see Figure 17-13).
Note 1: If the user reads the contents of the
SSPBUF before the falling edge of the
ninth clock, thus clearing the BF bit, the
CKP bit will not be cleared and clock
stretching will not occur.
2: The CKP bit can be set in software
regardless of the state of the BF bit. The
user should be careful to clear the BF bit
in the ISR before the next receive
sequence in order to prevent an overflow
condition.
17.4.4.2
17.4.4.3
Clock Stretching for 7-bit Slave
Transmit Mode
7-bit Slave Transmit mode implements clock stretching
by clearing the CKP bit after the falling edge of the ninth
clock, if the BF bit is clear. This occurs regardless of the
state of the SEN bit.
The user’s ISR must set the CKP bit before transmission is allowed to continue. By holding the SCL line low,
the user has time to service the ISR and load the contents of the SSPBUF before the master device can
initiate another transmit sequence (see Figure 17-9).
Note 1: If the user loads the contents of SSPBUF,
setting the BF bit before the falling edge of
the ninth clock, the CKP bit will not be
cleared and clock stretching will not occur.
2: The CKP bit can be set in software
regardless of the state of the BF bit.
17.4.4.4
Clock Stretching for 10-bit Slave
Transmit Mode
In 10-bit Slave Transmit mode, clock stretching is
controlled during the first two address sequences by
the state of the UA bit, just as it is in 10-bit Slave
Receive mode. The first two addresses are followed by
a third address sequence which contains the high order
bits of the 10-bit address and the R/W bit set to ‘1’. After
the third address sequence is performed, the UA bit is
not set, the module is now configured in Transmit
mode, and clock stretching is controlled by the BF flag
as in 7-bit Slave Transmit mode (see Figure 17-11).
Clock Stretching for 10-bit Slave
Receive Mode (SEN = 1)
In 10-bit Slave Receive mode, during the address
sequence, clock stretching automatically takes place
but CKP is not cleared. During this time, if the UA bit is
set after the ninth clock, clock stretching is initiated.
The UA bit is set after receiving the upper byte of the
10-bit address and following the receive of the second
byte of the 10-bit address with the R/W bit cleared to
‘0’. The release of the clock line occurs upon updating
SSPADD. Clock stretching will occur on each data
receive sequence as described in 7-bit mode.
Note:
If the user polls the UA bit and clears it by
updating the SSPADD register before the
falling edge of the ninth clock occurs and if
the user hasn’t cleared the BF bit by reading the SSPBUF register before that time,
then the CKP bit will still NOT be asserted
low. Clock stretching on the basis of the
state of the BF bit only occurs during a
data sequence, not an address sequence.
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17.4.4.5
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
FIGURE 17-12:
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 17-12).
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
CKP
Master device
asserts clock
Master device
deasserts clock
WR
SSPCON
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DS30491D-page 210
CKP
SSPOV (SSPCON)
BF (SSPSTAT)
(PIR1)
SSPIF
1
SCL
S
A7
2
A6
3
4
A4
5
A3
Receiving Address
A5
6
A2
7
A1
8
9
ACK
R/W = 0
3
4
D4
5
D3
Receiving Data
D5
Cleared in software
2
D6
If BF is cleared
prior to the falling
edge of the 9th clock,
CKP will not be reset
to ‘0’ and no clock
stretching will occur
SSPBUF is read
1
D7
6
D2
7
D1
9
ACK
1
D7
BF is set after falling
edge of the 9th clock,
CKP is reset to ‘0’ and
clock stretching occurs
8
D0
CKP
written
to ‘1’ in
software
2
D6
Clock is held low until
CKP is set to ‘1’
3
4
D4
5
D3
Receiving Data
D5
6
D2
7
D1
8
D0
Bus master
terminates
transfer
P
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
9
ACK
Clock is not held low
because ACK = 1
FIGURE 17-13:
SDA
Clock is not held low
because buffer full bit is
clear prior to falling edge
of 9th clock
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I2C SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 7-BIT ADDRESS)
2003-2013 Microchip Technology Inc.
2003-2013 Microchip Technology Inc.
UA (SSPSTAT)
SSPOV (SSPCON)
CKP
3
1
4
1
5
0
6
7
A9 A8
UA is set indicating that
the SSPADD needs to be
updated
8
9
ACK
R/W = 0
SSPBUF is written with
contents of SSPSR
Cleared in software
2
1
Receive First Byte of Address
BF (SSPSTAT)
(PIR1)
SSPIF
1
SCL
S
1
A7
2
4
5
A3
6
8
A0
Note:
An update of the SSPADD
register before the falling
edge of the ninth clock will
have no effect on UA and
UA will remain set.
UA is set indicating that
SSPADD needs to be
updated
Cleared by hardware when
SSPADD is updated with low
byte of address after falling edge
of ninth clock
7
A2 A1
Cleared in software
3
A4
Dummy read of SSPBUF
to clear BF flag
1
A5
Receive Second Byte of Address
A6
9
ACK
2
4
5
6
Cleared in software
3
D3 D2
7
8
Note:
An update of the SSPADD
register before the falling
edge of the ninth clock will
have no effect on UA and
UA will remain set.
9
ACK
1
4
5
6
D2
Cleared in software
3
CKP written to ‘1’
in software
2
D3
Receive Data Byte
D7 D6 D5 D4
Clock is held low until
CKP is set to ‘1’
D1 D0
Cleared by hardware when
SSPADD is updated with high
byte of address after falling edge
of ninth clock.
Dummy read of SSPBUF
to clear BF flag
1
D7 D6 D5 D4
Receive Data Byte
Clock is held low until
update of SSPADD has
taken place
7
8
9
ACK
Bus master
terminates
transfer
P
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
D1 D0
Clock is not held low
because ACK = 1
FIGURE 17-14:
SDA
Clock is held low until
update of SSPADD has
taken place
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17.4.5
GENERAL CALL ADDRESS
SUPPORT
If the general call address matches, the SSPSR is
transferred to the SSPBUF, the BF flag bit is set (eighth
bit) and on the falling edge of the ninth bit (ACK bit), the
SSPIF interrupt flag bit is set.
The addressing procedure for the I2C bus is such that
the first byte after the Start condition usually
determines which device will be the slave addressed by
the master. The exception is the general call address
which can address all devices. When this address is
used, all devices should, in theory, respond with an
Acknowledge.
When the interrupt is serviced, the source for the interrupt can be checked by reading the contents of the
SSPBUF. The value can be used to determine if the
address was device specific or a general call address.
In 10-bit mode, the SSPADD is required to be updated
for the second half of the address to match and the UA
bit is set (SSPSTAT). If the general call address is
sampled when the GCEN bit is set while the slave is
configured in 10-bit Address mode, then the second
half of the address is not necessary, the UA bit will not
be set and the slave will begin receiving data after the
Acknowledge (Figure 17-15).
The general call address is one of eight addresses
reserved for specific purposes by the I2C protocol. It
consists of all ‘0’s with R/W = 0.
The general call address is recognized when the General Call Enable bit (GCEN) is enabled (SSPCON2
is set). Following a Start bit detect, 8 bits are shifted into
the SSPSR and the address is compared against the
SSPADD. It is also compared to the general call
address and fixed in hardware.
FIGURE 17-15:
SLAVE MODE GENERAL CALL ADDRESS SEQUENCE
(7 OR 10-BIT ADDRESS MODE)
Address is compared to General Call Address
after ACK, set interrupt
Receiving Data
R/W = 0
General Call Address
SDA
ACK D7
ACK
D6
D5
D4
D3
D2
D1
D0
2
3
4
5
6
7
8
SCL
S
1
2
3
4
5
6
7
8
9
1
9
SSPIF
BF (SSPSTAT)
Cleared in software
SSPBUF is read
SSPOV (SSPCON1)
‘0’
GCEN (SSPCON2)
‘1’
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MASTER MODE
Note:
Master mode is enabled by setting and clearing the
appropriate SSPM bits in SSPCON1 and by setting the
SSPEN bit. In Master mode, the SCL and SDA lines
are manipulated by the MSSP hardware.
Master mode of operation is supported by 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 MSSP module is disabled.
Control of the I 2C bus may be taken when the P bit is
set or the bus is Idle, with both the S and P bits clear.
The following events will cause SSP interrupt flag bit,
SSPIF, to be set (SSP interrupt if enabled):
In Firmware Controlled Master mode, user code
conducts all I 2C bus operations based on Start and
Stop bit conditions.
•
•
•
•
•
Once Master mode is enabled, the user has six
options.
1.
2.
3.
4.
5.
6.
Assert a Start condition on SDA and SCL.
Assert a Repeated Start condition on SDA and
SCL.
Write to the SSPBUF register initiating
transmission of data/address.
Configure the I2C port to receive data.
Generate an Acknowledge condition at the end
of a received byte of data.
Generate a Stop condition on SDA and SCL.
FIGURE 17-16:
The MSSP module, when configured in
I2C Master mode, does not allow queueing
of events. For instance, the user is not
allowed to initiate a Start condition and
immediately write the SSPBUF register to
initiate transmission before the Start condition is complete. In this case, the SSPBUF
will not be written to and the WCOL bit will
be set, indicating that a write to the
SSPBUF did not occur.
Start Condition
Stop Condition
Data Transfer Byte Transmitted/Received
Acknowledge Transmit
Repeated Start
MSSP BLOCK DIAGRAM (I2C MASTER MODE)
SSPM3:SSPM0
SSPADD
Internal
Data Bus
Read
Write
SSPBUF
Baud
Rate
Generator
SDA
Shift
Clock
SDA In
SCL In
Bus Collision
2003-2013 Microchip Technology Inc.
LSb
Start bit, Stop bit,
Acknowledge
Generate
Start bit Detect
Stop bit Detect
Write Collision Detect
Clock Arbitration
State Counter for
end of XMIT/RCV
Clock Cntl
SCL
Receive Enable
SSPSR
MSb
Clock Arbitrate/WCOL Detect
(hold off clock source)
17.4.6
Set/Reset S, P, WCOL (SSPSTAT)
Set SSPIF, BCLIF
Reset ACKSTAT, PEN (SSPCON2)
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17.4.6.1
I2C Master Mode Operation
The master device generates all of the serial clock
pulses and the Start and Stop conditions. A transfer is
ended with a Stop condition or with a Repeated Start
condition. Since the Repeated Start condition is also
the beginning of the next serial transfer, the I2C bus will
not be released.
In Master Transmitter mode, serial data is output
through SDA while SCL outputs the serial clock. The
first byte transmitted contains the slave address of the
receiving device (7 bits) and the Read/Write (R/W) bit.
In this case, the R/W bit will be logic ‘0’. Serial data is
transmitted 8 bits at a time. After each byte is transmitted, an Acknowledge bit is received. Start and Stop
conditions are output to indicate the beginning and the
end of a serial transfer.
In Master Receive mode, the first byte transmitted contains the slave address of the transmitting device
(7 bits) and the R/W bit. In this case, the R/W bit will be
logic ‘1’. Thus, the first byte transmitted is a 7-bit slave
address followed by a ‘1’ to indicate a receive bit. Serial
data is received via SDA while SCL outputs the serial
clock. Serial data is received 8 bits at a time. After each
byte is received, an Acknowledge bit is transmitted.
Start and Stop conditions indicate the beginning and
end of transmission.
The Baud Rate Generator used for the SPI mode
operation is used to set the SCL clock frequency for
either 100 kHz, 400 kHz or 1 MHz I2C operation. See
Section 17.4.7 “Baud Rate Generator” for more
detail.
DS30491D-page 214
A typical transmit sequence would go as follows:
1.
The user generates a Start condition by setting
the Start enable bit, SEN (SSPCON2).
2. SSPIF is set. The MSSP module will wait the
required start time before any other operation
takes place.
3. The user loads the SSPBUF with the slave
address to transmit.
4. Address is shifted out the SDA pin until all 8 bits
are transmitted.
5. The MSSP module shifts in the ACK bit from the
slave device and writes its value into the
SSPCON2 register (SSPCON2).
6. The MSSP module generates an interrupt at the
end of the ninth clock cycle by setting the SSPIF
bit.
7. The user loads the SSPBUF with eight bits of
data.
8. Data is shifted out the SDA pin until all 8 bits are
transmitted.
9. The MSSP module shifts in the ACK bit from the
slave device and writes its value into the
SSPCON2 register (SSPCON2).
10. The MSSP module generates an interrupt at the
end of the ninth clock cycle by setting the SSPIF
bit.
11. The user generates a Stop condition by setting
the Stop enable bit PEN (SSPCON2).
12. Interrupt is generated once the Stop condition is
complete.
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17.4.7
BAUD RATE GENERATOR
I2C
In
Master mode, the Baud Rate Generator (BRG)
reload value is placed in the lower 7 bits of the
SSPADD register (Figure 17-17). When a write occurs
to SSPBUF, the Baud Rate Generator will automatically
begin counting. The BRG counts down to ‘0’ and stops
until another reload has taken place. The BRG count is
decremented twice per instruction cycle (TCY) on the
Q2 and Q4 clocks. In I2C Master mode, the BRG is
reloaded automatically.
FIGURE 17-17:
Once the given operation is complete (i.e., transmission of the last data bit is followed by ACK), the internal
clock will automatically stop counting and the SCL pin
will remain in its last state.
Table 17-3 demonstrates clock rates based on
instruction cycles and the BRG value loaded into
SSPADD.
BAUD RATE GENERATOR BLOCK DIAGRAM
SSPM3:SSPM0
SSPM3:SSPM0
Reload
SCL
Control
CLKO
TABLE 17-3:
Note 1:
SSPADD
Reload
BRG Down Counter
FOSC/4
I2C CLOCK RATE w/BRG
FCY
FCY*2
BRG Value
FSCL
(2 Rollovers of BRG)
10 MHz
20 MHz
19h
400 kHz(1)
10 MHz
20 MHz
20h
312.5 kHz
10 MHz
20 MHz
64h
100 kHz
4 MHz
8 MHz
0Ah
400 kHz(1)
4 MHz
8 MHz
0Dh
308 kHz
4 MHz
8 MHz
28h
100 kHz
1 MHz
2 MHz
03h
333 kHz(1)
1 MHz
2 MHz
0Ah
100 kHz
1 MHz
2 MHz
00h
1 MHz(1)
The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than
100 kHz) in all details but may be used with care where higher rates are required by the application.
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17.4.7.1
Clock Arbitration
Clock arbitration occurs when the master, during any
receive, transmit or Repeated Start/Stop condition,
deasserts the SCL pin (SCL allowed to float high).
When the SCL pin is allowed to float high, the Baud
Rate Generator (BRG) is suspended from counting
until the SCL pin is actually sampled high. When the
FIGURE 17-18:
SCL pin is sampled high, the Baud Rate Generator is
reloaded with the contents of SSPADD and
begins counting. This ensures that the SCL high time
will always be at least one BRG rollover count in the
event that the clock is held low by an external device
(Figure 17-18).
BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION
SDA
DX
DX-1
SCL deasserted but slave holds
SCL low (clock arbitration)
SCL allowed to transition high
SCL
BRG decrements on
Q2 and Q4 cycles
BRG
Value
03h
02h
01h
00h (hold off)
03h
02h
SCL is sampled high, reload takes
place and BRG starts its count
BRG
Reload
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17.4.8
I2C MASTER MODE START
CONDITION TIMING
17.4.8.1
If the user writes the SSPBUF when a Start sequence
is in progress, the WCOL is set and the contents of the
buffer are unchanged (the write doesn’t occur).
To initiate a Start condition, the user sets the Start Condition Enable bit, SEN (SSPCON2). If the SDA and
SCL pins are sampled high, the Baud Rate Generator
is reloaded with the contents of SSPADD and
starts its count. If SCL and SDA are both sampled high
when the Baud Rate Generator times out (TBRG), the
SDA pin is driven low. The action of the SDA being
driven low while SCL is high is the Start condition and
causes the S bit (SSPSTAT) to be set. Following
this, the Baud Rate Generator is reloaded with the
contents of SSPADD and resumes its count.
When the Baud Rate Generator times out (TBRG), the
SEN bit (SSPCON2) will be automatically cleared
by hardware, the Baud Rate Generator is suspended,
leaving the SDA line held low and the Start condition is
complete.
Note:
WCOL Status Flag
Note:
Because queueing of events is not
allowed, writing to the lower 5 bits of
SSPCON2 is disabled until the Start
condition is complete.
If at the beginning of the Start condition,
the SDA and SCL pins are already sampled low or if during the Start condition, the
SCL line is sampled low before the SDA
line is driven low, a bus collision occurs,
the Bus Collision Interrupt Flag, BCLIF, is
set, the Start condition is aborted and the
I2C module is reset into its Idle state.
FIGURE 17-19:
FIRST START BIT TIMING
Set S bit (SSPSTAT)
Write to SEN bit occurs here
SDA = 1,
SCL = 1
TBRG
At completion of Start bit,
hardware clears SEN bit
and sets SSPIF bit
TBRG
Write to SSPBUF occurs here
1st bit
SDA
2nd bit
TBRG
SCL
TBRG
S
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17.4.9
I2C MASTER MODE REPEATED
START CONDITION TIMING
Immediately following the SSPIF bit getting set, the
user may write the SSPBUF with the 7-bit address in
7-bit mode, or the default first address in 10-bit mode.
After the first eight bits are transmitted and an ACK is
received, the user may then transmit an additional eight
bits of address (10-bit mode) or eight bits of data (7-bit
mode).
A Repeated Start condition occurs when the RSEN bit
(SSPCON2) is programmed high and the I2C logic
module is in the Idle state. When the RSEN bit is set,
the SCL pin is asserted low. When the SCL pin is
sampled low, the Baud Rate Generator is loaded with
the contents of SSPADD and begins counting.
The SDA pin is released (brought high) for one Baud
Rate Generator count (TBRG). When the Baud Rate
Generator times out, if SDA is sampled high, the SCL
pin will be deasserted (brought high). When SCL is
sampled high, the Baud Rate Generator is reloaded
with the contents of SSPADD and begins counting. SDA and SCL must be sampled high for one TBRG.
This action is then followed by assertion of the SDA pin
(SDA = 0) for one TBRG while SCL is high. Following
this, the RSEN bit (SSPCON2) will be automatically
cleared and the Baud Rate Generator will not be
reloaded, leaving the SDA pin held low. As soon as a
Start condition is detected on the SDA and SCL pins,
the S bit (SSPSTAT) will be set. The SSPIF bit will
not be set until the Baud Rate Generator has timed out.
17.4.9.1
WCOL Status Flag
If the user writes the SSPBUF when a Repeated Start
sequence is in progress, the WCOL is set and the contents of the buffer are unchanged (the write doesn’t
occur).
Note:
Because queueing of events is not
allowed, writing of the lower 5 bits of
SSPCON2 is disabled until the Repeated
Start condition is complete.
Note 1: If RSEN is programmed while any other
event is in progress, it will not take effect.
2: A bus collision during the Repeated Start
condition occurs if:
• SDA is sampled low when SCL goes
from low-to-high.
• SCL goes low before SDA is
asserted low. This may indicate that
another master is attempting to
transmit a data ‘1’.
FIGURE 17-20:
REPEAT START CONDITION WAVEFORM
Set S (SSPSTAT)
Write to SSPCON2
occurs here.
SDA = 1,
SCL (no change).
SDA = 1,
SCL = 1
TBRG
TBRG
At completion of Start bit,
hardware clears RSEN bit
and sets SSPIF
TBRG
1st bit
SDA
Falling edge of ninth clock,
end of Xmit
SCL
Write to SSPBUF occurs here
TBRG
TBRG
Sr = Repeated Start
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17.4.10
I2C MASTER MODE
TRANSMISSION
Transmission of a data byte, a 7-bit address, or the
other half of a 10-bit address is accomplished by simply
writing a value to the SSPBUF register. This action will
set the Buffer Full flag bit, BF and allow the Baud Rate
Generator to begin counting and start the next transmission. Each bit of address/data will be shifted out
onto the SDA pin after the falling edge of SCL is
asserted (see data hold time specification parameter
#106). SCL is held low for one Baud Rate Generator
rollover count (TBRG). Data should be valid before SCL
is released high (see data setup time specification
parameter #107). When the SCL pin is released high, it
is held that way for TBRG. The data on the SDA pin
must remain stable for that duration and some hold
time after the next falling edge of SCL. After the eighth
bit is shifted out (the falling edge of the eighth clock),
the BF flag is cleared and the master releases SDA.
This allows the slave device being addressed to
respond with an ACK bit during the ninth bit time if an
address match occurred, or if data was received
properly. The status of ACK is written into the ACKDT
bit on the falling edge of the ninth clock. If the master
receives an Acknowledge, the Acknowledge Status bit,
ACKSTAT, is cleared. If not, the bit is set. After the ninth
clock, the SSPIF bit is set and the master clock (Baud
Rate Generator) is suspended until the next data byte
is loaded into the SSPBUF, leaving SCL low and SDA
unchanged (Figure 17-21).
After the write to the SSPBUF, each bit of the address
will be shifted out on the falling edge of SCL until all
seven address bits and the R/W bit are completed. On
the falling edge of the eighth clock, the master will
deassert the SDA pin, allowing the slave to respond
with an Acknowledge. On the falling edge of the ninth
clock, the master will sample the SDA pin to see if the
address was recognized by a slave. The status of the
ACK bit is loaded into the ACKSTAT status bit
(SSPCON2). Following the falling edge of the ninth
clock transmission of the address, the SSPIF is set, the
BF flag is cleared and the Baud Rate Generator is
turned off until another write to the SSPBUF takes
place, holding SCL low and allowing SDA to float.
17.4.10.1
17.4.10.3
ACKSTAT Status Flag
In Transmit mode, the ACKSTAT bit (SSPCON2) is
cleared when the slave has sent an Acknowledge
(ACK = 0) and is set when the slave does not Acknowledge (ACK = 1). A slave sends an Acknowledge when
it has recognized its address (including a general call)
or when the slave has properly received its data.
17.4.11
I2C MASTER MODE RECEPTION
Master mode reception is enabled by programming the
receive enable bit, RCEN (SSPCON2).
Note:
The MSSP module must be in an Idle state
before the RCEN bit is set or the RCEN bit
will be disregarded.
The Baud Rate Generator begins counting and on each
rollover, the state of the SCL pin changes (high-to-low/
low-to-high) and data is shifted into the SSPSR. After the
falling edge of the eighth clock, the receive enable flag is
automatically cleared, the contents of the SSPSR are
loaded into the SSPBUF, the BF flag bit is set, the SSPIF
flag bit is set and the Baud Rate Generator is suspended
from counting, holding SCL low. The MSSP is now in Idle
state awaiting the next command. When the buffer is
read by the CPU, the BF flag bit is automatically cleared.
The user can then send an Acknowledge bit at the end
of reception by setting the Acknowledge sequence
enable bit, ACKEN (SSPCON2).
17.4.11.1
BF Status Flag
In receive operation, the BF bit is set when an address
or data byte is loaded into SSPBUF from SSPSR. It is
cleared when the SSPBUF register is read.
17.4.11.2
SSPOV Status Flag
In receive operation, the SSPOV bit is set when 8 bits
are received into the SSPSR and the BF flag bit is
already set from a previous reception.
17.4.11.3
WCOL Status Flag
If the user writes the SSPBUF when a receive is
already in progress (i.e., SSPSR is still shifting in a data
byte), the WCOL bit is set and the contents of the buffer
are unchanged (the write doesn’t occur).
BF Status Flag
In Transmit mode, the BF bit (SSPSTAT) is set
when the CPU writes to SSPBUF and is cleared when
all 8 bits are shifted out.
17.4.10.2
WCOL Status Flag
If the user writes the SSPBUF when a transmit is
already in progress (i.e., SSPSR is still shifting out a
data byte), the WCOL is set and the contents of the
buffer are unchanged (the write doesn’t occur).
WCOL must be cleared in software.
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S
R/W
PEN
SEN
BF (SSPSTAT)
SSPIF
SCL
SDA
A6
A5
A4
A3
A2
A1
3
4
5
Cleared in software
2
6
7
8
9
After Start condition, SEN cleared by hardware
SSPBUF written
1
D7
1
SCL held low
while CPU
responds to SSPIF
ACK = 0
R/W = 0
SSPBUF written with 7-bit address and R/W
start transmit
A7
Transmit Address to Slave
3
D5
4
D4
5
D3
6
D2
7
D1
8
D0
SSPBUF is written in software
Cleared in software service routine
from SSP interrupt
2
D6
Transmitting Data or Second Half
of 10-bit Address
From slave clear ACKSTAT bit SSPCON2
P
Cleared in software
9
ACK
ACKSTAT in
SSPCON2 = 1
FIGURE 17-21:
SEN = 0
Write SSPCON2 SEN = 1,
Start condition begins
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I 2C MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS)
2003-2013 Microchip Technology Inc.
2003-2013 Microchip Technology Inc.
S
ACKEN
SSPOV
BF
(SSPSTAT)
SDA = 0, SCL = 1
while CPU
responds to SSPIF
SSPIF
SCL
SDA
1
A7
2
4
5
Cleared in software
3
6
A6 A5 A4 A3 A2
Transmit Address to Slave
7
A1
8
9
R/W = 1
ACK
ACK from Slave
2
3
5
6
7
8
D0
9
ACK
2
3
4
5
6
7
Cleared in software
Set SSPIF interrupt
at end of Acknowledge
sequence
Data shifted in on falling edge of CLK
1
D7 D6 D5 D4 D3 D2 D1
Cleared in
software
Set SSPIF at end
of receive
9
ACK is not sent
ACK
P
Set SSPIF interrupt
at end of Acknowledge sequence
Bus master
terminates
transfer
Set P bit
(SSPSTAT)
and SSPIF
PEN bit = 1
written here
SSPOV is set because
SSPBUF is still full
8
D0
RCEN cleared
automatically
Set ACKEN, start Acknowledge sequence,
SDA = ACKDT = 1
Receiving Data from Slave
RCEN = 1,
start next receive
ACK from Master
SDA = ACKDT = 0
Last bit is shifted into SSPSR and
contents are unloaded into SSPBUF
Cleared in software
Set SSPIF interrupt
at end of receive
4
Cleared in software
1
D7 D6 D5 D4 D3 D2 D1
Receiving Data from Slave
RCEN cleared
automatically
Master configured as a receiver
by programming SSPCON2 (RCEN = 1)
FIGURE 17-22:
SEN = 0
Write to SSPBUF occurs here,
start XMIT
Write to SSPCON2 (SEN = 1),
begin Start Condition
Write to SSPCON2
to start Acknowledge sequence,
SDA = ACKDT (SSPCON2) = 0
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17.4.12
ACKNOWLEDGE SEQUENCE
TIMING
17.4.13
A Stop bit is asserted on the SDA pin at the end of a
receive/transmit by setting the Stop Sequence Enable
bit, PEN (SSPCON2). At the end of a receive/
transmit, the SCL line is held low after the falling edge
of the ninth clock. When the PEN bit is set, the master
will assert the SDA line low. When the SDA line is
sampled low, the Baud Rate Generator is reloaded and
counts down to ‘0’. When the Baud Rate Generator
times out, the SCL pin will be brought high and one
TBRG (Baud Rate Generator rollover count) later, the
SDA pin will be deasserted. When the SDA pin is sampled high while SCL is high, the P bit (SSPSTAT) is
set. A TBRG later, the PEN bit is cleared and the SSPIF
bit is set (Figure 17-24).
An Acknowledge sequence is enabled by setting
the Acknowledge Sequence Enable bit, ACKEN
(SSPCON2). When this bit is set, the SCL pin is
pulled low and the contents of the Acknowledge data bit
are presented on the SDA pin. If the user wishes to generate an Acknowledge, then the ACKDT bit should be
cleared. If not, the user should set the ACKDT bit before
starting an Acknowledge sequence. The Baud Rate
Generator then counts for one rollover period (TBRG)
and the SCL pin is deasserted (pulled high). When the
SCL pin is sampled high (clock arbitration), the Baud
Rate Generator counts for TBRG. The SCL pin is then
pulled low. Following this, the ACKEN bit is automatically
cleared, the Baud Rate Generator is turned off and the
MSSP module then goes into Idle mode (Figure 17-23).
17.4.12.1
17.4.13.1
WCOL Status Flag
If the user writes the SSPBUF when a Stop sequence
is in progress, then the WCOL bit is set and the contents of the buffer are unchanged (the write doesn’t
occur).
WCOL Status Flag
If the user writes the SSPBUF when an Acknowledge
sequence is in progress, then WCOL is set and the
contents of the buffer are unchanged (the write doesn’t
occur).
FIGURE 17-23:
STOP CONDITION TIMING
ACKNOWLEDGE SEQUENCE WAVEFORM
Acknowledge sequence starts here,
write to SSPCON2
ACKEN = 1, ACKDT = 0
ACKEN automatically cleared
TBRG
TBRG
SDA
ACK
D0
SCL
8
9
SSPIF
Set SSPIF at the end
of receive
Cleared in
software
Cleared in
software
Set SSPIF at the end
of Acknowledge sequence
Note: TBRG = one Baud Rate Generator period.
FIGURE 17-24:
STOP CONDITION RECEIVE OR TRANSMIT MODE
SCL = 1 for TBRG, followed by SDA = 1 for TBRG
after SDA sampled high. P bit (SSPSTAT) is set.
Write to SSPCON2,
set PEN
Falling edge of
9th clock
TBRG
SCL
SDA
PEN bit (SSPCON2) is cleared by
hardware and the SSPIF bit is set
ACK
P
TBRG
TBRG
TBRG
SCL brought high after TBRG
SDA asserted low before rising edge of clock
to setup Stop condition
Note: TBRG = one Baud Rate Generator period.
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17.4.14
SLEEP OPERATION
17.4.17
I2C
While in Sleep mode, the
module can receive
addresses or data and when an address match or complete byte transfer occurs, wake the processor from
Sleep (if the MSSP interrupt is enabled).
17.4.15
Multi-Master mode support is achieved by bus arbitration. When the master outputs address/data bits onto
the SDA pin, arbitration takes place when the master
outputs a ‘1’ on SDA by letting SDA float high and
another master asserts a ‘0’. When the SCL pin floats
high, data should be stable. If the expected data on
SDA is a ‘1’ and the data sampled on the SDA pin = 0,
then a bus collision has taken place. The master will set
the Bus Collision Interrupt Flag, BCLIF and reset the
I2C port to its Idle state (Figure 17-25).
EFFECT OF A RESET
A Reset disables the MSSP module and terminates the
current transfer.
17.4.16
MULTI-MASTER MODE
In Multi-Master mode, the interrupt generation on the
detection of the Start and Stop conditions allows the
determination of when the bus is free. The Stop (P) and
Start (S) bits are cleared from a Reset or when the
MSSP module is disabled. Control of the I 2C bus may
be taken when the P bit (SSPSTAT) is set or the
bus is Idle, with 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.
If a transmit was in progress when the bus collision
occurred, the transmission is halted, the BF flag is
cleared, the SDA and SCL lines are deasserted and the
SSPBUF can be written to. When the user services the
bus collision Interrupt Service Routine and if the I2C
bus is free, the user can resume communication by
asserting a Start condition.
In multi-master operation, the SDA line must be monitored for arbitration to see if the signal level is the
expected output level. This check is performed in
hardware with the result placed in the BCLIF bit.
If a Start, Repeated Start, Stop, or Acknowledge condition was in progress when the bus collision occurred,
the condition is aborted, the SDA and SCL lines are
deasserted, and the respective control bits in the
SSPCON2 register are cleared. When the user services the bus collision Interrupt Service Routine and if
the I2C bus is free, the user can resume communication
by asserting a Start condition.
The states where arbitration can be lost are:
•
•
•
•
•
MULTI -MASTER COMMUNICATION,
BUS COLLISION AND
BUS ARBITRATION
Address Transfer
Data Transfer
A Start Condition
A Repeated Start Condition
An Acknowledge Condition
The master will continue to monitor the SDA and SCL
pins. If a Stop condition occurs, the SSPIF bit will be set.
A write to the SSPBUF will start the transmission of
data at the first data bit regardless of where the
transmitter left off when the bus collision occurred.
In Multi-Master mode, the interrupt generation on the
detection of Start and Stop conditions allows the determination of when the bus is free. Control of the I2C bus can
be taken when the P bit is set in the SSPSTAT register or
the bus is Idle and the S and P bits are cleared.
FIGURE 17-25:
BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE
Data changes
while SCL = 0
SDA line pulled low
by another source
SDA released
by master
Sample SDA. While SCL is high,
data doesn’t match what is driven
by the master.
Bus collision has occurred.
SDA
SCL
Set bus collision
interrupt (BCLIF)
BCLIF
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17.4.17.1
Bus Collision During a Start
Condition
During a Start condition, a bus collision occurs if:
a)
b)
SDA or SCL are sampled low at the beginning of
the Start condition (Figure 17-26).
SCL is sampled low before SDA is asserted low
(Figure 17-27).
During a Start condition, both the SDA and the SCL
pins are monitored.
If the SDA pin is sampled low during this count, the
BRG is reset and the SDA line is asserted early
(Figure 17-28). If, however, a ‘1’ is sampled on the SDA
pin, the SDA pin is asserted low at the end of the BRG
count. The Baud Rate Generator is then reloaded and
counts down to ‘0’ and during this time, if the SCL pins
are sampled as ‘0’, a bus collision does not occur. At
the end of the BRG count, the SCL pin is asserted low.
Note:
If the SDA pin is already low or the SCL pin is already
low, then all of the following occur:
• the Start condition is aborted,
• the BCLIF flag is set, and
• the MSSP module is reset to its Idle state
(Figure 17-26).
The Start condition begins with the SDA and SCL pins
deasserted. When the SDA pin is sampled high, the
Baud Rate Generator is loaded from SSPADD
and counts down to ‘0’. If the SCL pin is sampled low
while SDA is high, a bus collision occurs because it is
assumed that another master is attempting to drive a
data ‘1’ during the Start condition.
FIGURE 17-26:
The reason that bus collision is not a factor
during a Start condition is that no two bus
masters can assert a Start condition at the
exact same time. Therefore, one master
will always assert SDA before the other.
This condition does not cause a bus
collision because the two masters must be
allowed to arbitrate the first address following the Start condition. If the address is the
same, arbitration must be allowed to
continue into the data portion, Repeated
Start or Stop conditions.
BUS COLLISION DURING START CONDITION (SDA ONLY)
SDA goes low before the SEN bit is set.
Set BCLIF;
S bit and SSPIF set because
SDA = 0, SCL = 1.
SDA
SCL
Set SEN, enable Start
condition if SDA = 1, SCL = 1
SEN cleared automatically because of bus collision.
SSP module reset into Idle state.
SEN
BCLIF
SDA sampled low before
Start condition. Set BCLIF;
S bit and SSPIF set because
SDA = 0, SCL = 1.
SSPIF and BCLIF are
cleared in software
S
SSPIF
SSPIF and BCLIF are
cleared in software
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FIGURE 17-27:
BUS COLLISION DURING START CONDITION (SCL = 0)
SDA = 0, SCL = 1
TBRG
TBRG
SDA
Set SEN, enable Start
sequence if SDA = 1, SCL = 1
SCL
SCL = 0 before SDA = 0,
bus collision occurs. Set BCLIF.
SEN
SCL = 0 before BRG time-out,
bus collision occurs. Set BCLIF.
BCLIF
Interrupt cleared
in software
S
‘0’
‘0’
SSPIF
‘0’
‘0’
FIGURE 17-28:
BRG RESET DUE TO SDA ARBITRATION DURING START CONDITION
SDA = 0, SCL = 1
Set S
Less than TBRG
SDA
Set SSPIF
TBRG
SDA pulled low by other master.
Reset BRG and assert SDA.
SCL
S
SCL pulled low after BRG
Time-out
SEN
BCLIF
Set SEN, enable START
sequence if SDA = 1, SCL = 1
‘0’
S
SSPIF
SDA = 0, SCL = 1,
set SSPIF
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Interrupts cleared
in software
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17.4.17.2
Bus Collision During a Repeated
Start Condition
reloaded and begins counting. If SDA goes from high to
low before the BRG times out, no bus collision occurs
because no two masters can assert SDA at exactly the
same time.
During a Repeated Start condition, a bus collision
occurs if:
a)
b)
If SCL goes from high to low before the BRG times out
and SDA has not already been asserted, a bus collision
occurs. In this case, another master is attempting to
transmit a data ‘1’ during the Repeated Start condition
(see Figure 17-30).
A low level is sampled on SDA when SCL goes
from low level to high level.
SCL goes low before SDA is asserted low,
indicating that another master is attempting to
transmit a data ‘1’.
If, at the end of the BRG time-out, both SCL and SDA
are still high, the SDA pin is driven low and the BRG is
reloaded and begins counting. At the end of the count,
regardless of the status of the SCL pin, the SCL pin is
driven low and the Repeated Start condition is
complete.
When the user deasserts SDA and the pin is allowed to
float high, the BRG is loaded with SSPADD and
counts down to ‘0’. The SCL pin is then deasserted and
when sampled high, the SDA pin is sampled.
If SDA is low, a bus collision has occurred (i.e., another
master is attempting to transmit a data ‘0’, see
Figure 17-29). If SDA is sampled high, the BRG is
FIGURE 17-29:
BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)
SDA
SCL
Sample SDA when SCL goes high.
If SDA = 0, set BCLIF and release SDA and SCL.
RSEN
BCLIF
Cleared in software
‘0’
S
‘0’
SSPIF
FIGURE 17-30:
BUS COLLISION DURING REPEATED START CONDITION (CASE 2)
TBRG
TBRG
SDA
SCL
BCLIF
SCL goes low before SDA,
set BCLIF. Release SDA and SCL.
Interrupt cleared
in software
RSEN
S
‘0’
SSPIF
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17.4.17.3
Bus Collision During a Stop
Condition
The Stop condition begins with SDA asserted low.
When SDA is sampled low, the SCL pin is allowed to
float. When the pin is sampled high (clock arbitration),
the Baud Rate Generator is loaded with SSPADD
and counts down to ‘0’. After the BRG times out, SDA
is sampled. If SDA is sampled low, a bus collision has
occurred. This is due to another master attempting to
drive a data ‘0’ (Figure 17-31). If the SCL pin is
sampled low before SDA is allowed to float high, a bus
collision occurs. This is another case of another master
attempting to drive a data ‘0’ (Figure 17-32).
Bus collision occurs during a Stop condition if:
a)
b)
After the SDA pin has been deasserted and
allowed to float high, SDA is sampled low after
the BRG has timed out.
After the SCL pin is deasserted, SCL is sampled
low before SDA goes high.
FIGURE 17-31:
BUS COLLISION DURING A STOP CONDITION (CASE 1)
TBRG
TBRG
TBRG
SDA sampled
low after TBRG,
set BCLIF
SDA
SDA asserted low
SCL
PEN
BCLIF
P
‘0’
SSPIF
‘0’
FIGURE 17-32:
BUS COLLISION DURING A STOP CONDITION (CASE 2)
TBRG
TBRG
TBRG
SDA
Assert SDA
SCL goes low before SDA goes high,
set BCLIF
SCL
PEN
BCLIF
P
‘0’
SSPIF
‘0’
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NOTES:
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18.0
ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (USART)
The Universal Synchronous Asynchronous Receiver
Transmitter (USART) module is one of the two serial
I/O modules. (USART is also known as a Serial
Communications Interface or SCI.) The USART can be
configured as a full-duplex asynchronous system that
can communicate with peripheral devices, such as
CRT terminals and personal computers. It can also be
configured as a half-duplex synchronous system that
can communicate with peripheral devices, such as A/D
or D/A integrated circuits, serial EEPROMs, etc.
The Enhanced USART module implements additional
features, including automatic baud rate detection and
calibration, automatic wake-up on sync break reception
and 12-bit break character transmit. These make it
ideally suited for use in Local Interconnect Network bus
(LIN bus) systems.
In order to configure pins RC6/TX/CK and RC7/RX/DT
as the Universal Synchronous Asynchronous Receiver
Transmitter:
• SPEN (RCSTA) bit must be set (= 1),
• TRISC bit must be set (= 1), and
• TRISC bit must be set (= 1).
Note:
The USART control will automatically
reconfigure the pin from input to output as
needed.
The operation of the Enhanced USART module is
controlled through three registers:
• Transmit Status and Control (TXSTA)
• Receive Status and Control (RCSTA)
• Baud Rate Control (BAUDCON)
These are detailed on the following pages in
Register 18-1, Register 18-2 and Register 18-3,
respectively.
The USART can be configured in the following modes:
• Asynchronous (full-duplex) with:
- Auto-wake-up on character reception
- Auto-baud calibration
- 12-bit break character transmission
• Synchronous – Master (half-duplex) with
selectable clock polarity
• Synchronous – Slave (half-duplex) with selectable
clock polarity
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REGISTER 18-1:
TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-0
CSRC
bit 7
R/W-0
TX9
R/W-0
TXEN
R/W-0
SYNC
R/W-0
SENDB
R/W-0
BRGH
R-1
TRMT
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
bit 4
SYNC: USART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3
SENDB: 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:
R/W-0
TX9D
bit 0
SREN/CREN overrides TXEN in Sync mode.
Legend:
DS30491D-page 230
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
2003-2013 Microchip Technology Inc.
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REGISTER 18-2:
RCSTA: RECEIVE STATUS AND CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R-0
R-x
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
bit 7
bit 0
bit 7
SPEN: Serial Port Enable bit
1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins)
0 = Serial port disabled (held 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, enables interrupt and loads the receive buffer when RSR
is set
0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 9-bit (RX9 = 0):
Don’t care.
bit 2
FERR: Framing Error bit
1 = Framing error (can be updated by reading RCREG register and receiving 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 an address/data bit or a parity bit and must be calculated by user firmware.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
DS30491D-page 231
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PIC18F6585/8585/6680/8680
REGISTER 18-3:
BAUDCON: BAUD RATE CONTROL REGISTER
U-0
R-1
U-0
R/W-0
R/W-0
U-0
R/W-0
R/W-0
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
RCIDL: Receive Operation Idle Status bit
1 = Receive operation is Idle
0 = Receive operation is active
bit 5
Unimplemented: Read as ‘0’
bit 4
SCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
Unused in this mode.
Synchronous mode:
1 = Idle state for clock (CK) is a high level
0 = Idle state for clock (CK) is a low level
bit 3
BRG16: 16-bit Baud Rate Register Enable bit
1 = 16-bit Baud Rate Generator – SPBRGH and SPBRG
0 = 8-bit Baud Rate Generator – SPBRG only (Compatible mode), SPBRGH value ignored
bit 2
Unimplemented: Read as ‘0’
bit 1
WUE: Wake-up Enable bit
Asynchronous mode:
1 = USART will continue to sample the RX pin – interrupt generated on falling edge; bit cleared
in hardware on following rising edge
0 = RX pin not monitored or rising edge detected
Synchronous mode:
Unused in this mode.
bit 0
ABDEN: Auto-Baud Detect Enable bit
Asynchronous mode:
1 = Enable baud rate measurement on the next character – requires reception of a sync field
(55h); cleared in hardware upon completion
0 = Baud rate measurement disabled or completed
Synchronous mode:
Unused in this mode.
Legend:
DS30491D-page 232
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
2003-2013 Microchip Technology Inc.
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18.1
USART 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 USART. By default, the BRG operates in
8-bit mode; setting the BRG16 bit (BAUDCON)
selects 16-bit mode.
The SPBRGH:SPBRG register pair controls the period
of a free-running timer. In Asynchronous mode, bits
BRGH (TXSTA) and BRG16 also control the baud
rate. In Synchronous mode, bit BRGH is ignored.
Table 18-1 shows the formula for computation of the
baud rate for different USART modes which only apply
in 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 18-1. From this,
TABLE 18-1:
the error in baud rate can be determined. An example
calculation is shown in Example 18-1. Typical baud
rates and error values for the various Asynchronous
modes are shown in Table 18-2. 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.
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.
18.1.1
SAMPLING
The data on the RC7/RX/DT pin is sampled three times
by a majority detect circuit to determine if a high or a
low level is present at the RX pin.
BAUD RATE FORMULAS
Configuration Bits
BRG/USART Mode
Baud Rate Formula
8-bit/Asynchronous
FOSC/[64 (n + 1)]
SYNC
BRG16
BRGH
0
0
0
0
0
1
8-bit/Asynchronous
0
1
0
16-bit/Asynchronous
0
1
1
16-bit/Asynchronous
1
0
x
8-bit/Synchronous
1
1
x
16-bit/Synchronous
FOSC/[16 (n + 1)]
FOSC/[4 (n + 1)]
Legend: x = Don’t care, n = Value of SPBRGH:SPBRG register pair
EXAMPLE 18-1:
CALCULATING BAUD RATE ERROR
For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG:
Desired Baud Rate = FOSC/(64 ([SPBRGH:SPBRG] + 1))
Solving for SPBRGH:SPBRG:
X
= ((FOSC/Desired Baud Rate)/64) – 1
= ((16000000/9600)/64) – 1
= [25.042] = 25
Calculated Baud Rate= 16000000/(64 (25 + 1))
= 9615
Error
= (Calculated Baud Rate – Desired Baud Rate)/Desired Baud Rate
= (9615 – 9600)/9600 = 0.16%
TABLE 18-2:
Name
REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
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
0000 0010
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-0 0-00
-1-0 0-00
BAUDCON
SPBRGH
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, - = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 18-3:
BAUD RATES FOR ASYNCHRONOUS MODES
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
(K)
FOSC = 40.000 MHz
Actual
Rate
(K)
%
Error
0.3
—
—
1.2
—
2.4
9.6
FOSC = 20.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
—
—
—
—
1.221
2.441
1.73
255
9.615
0.16
64
19.2
19.531
1.73
57.6
56.818
115.2
125.000
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
—
—
1.73
255
1.202
2.404
0.16
129
9.766
1.73
31
31
19.531
1.73
-1.36
10
62.500
8.51
4
104.167
SPBRG
value
FOSC = 8.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
—
—
—
0.16
129
1201
-0.16
103
2.404
0.16
64
2403
-0.16
51
9.766
1.73
15
9615
-0.16
12
15
19.531
1.73
7
—
—
—
8.51
4
52.083
-9.58
2
—
—
—
-9.58
2
78.125
-32.18
1
—
—
—
SPBRG
value
SPBRG
value
SPBRG
value
(decimal)
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
2.4
FOSC = 2.000 MHz
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
(decimal)
Actual
Rate
(K)
%
Error
207
300
-0.16
103
300
-0.16
0.16
51
1201
51
-0.16
25
1201
-0.16
2.404
0.16
25
12
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
—
—
—
—
—
—
SPBRG
value
SPBRG
value
SPBRG
value
(decimal)
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
(K)
FOSC = 40.000 MHz
Actual
Rate
(K)
%
Error
0.3
—
—
1.2
—
2.4
—
FOSC = 20.000 MHz
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
—
—
—
—
—
—
—
—
—
SPBRG
value
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
—
—
—
—
—
—
—
SPBRG
value
FOSC = 8.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
—
—
—
—
—
—
—
—
2.441
1.73
255
2403
-0.16
207
(decimal)
—
9.6
9.766
1.73
255
9.615
0.16
129
9.615
0.16
64
9615
-0.16
51
19.2
19.231
0.16
129
19.231
0.16
64
19.531
1.73
31
19230
-0.16
25
57.6
58.140
0.94
42
56.818
-1.36
21
56.818
-1.36
10
55555
3.55
8
115.2
113.636
-1.36
21
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
0.3
1.2
—
1.202
—
0.16
2.4
2.404
9.6
9.615
19.2
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
207
—
1201
—
-0.16
0.16
103
2403
0.16
25
9615
19.231
0.16
12
57.6
62.500
8.51
115.2
125.000
8.51
DS30491D-page 234
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
103
300
1201
-0.16
-0.16
207
51
-0.16
51
2403
-0.16
25
-0.16
12
—
—
—
—
—
—
—
—
—
3
—
—
—
—
—
—
1
—
—
—
—
—
—
SPBRG
value
SPBRG
value
SPBRG
value
(decimal)
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TABLE 18-3:
BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
(K)
FOSC = 40.000 MHz
Actual
Rate
(K)
%
Error
0.3
0.300
0.00
1.2
1.200
2.4
FOSC = 20.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
8332
0.300
0.02
0.02
2082
1.200
2.402
0.06
1040
9.6
9.615
0.16
19.2
19.231
0.16
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
4165
0.300
0.02
-0.03
1041
1.200
2.399
-0.03
520
259
9.615
0.16
129
19.231
0.16
SPBRG
value
FOSC = 8.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
2082
300
-0.04
1665
-0.03
520
1201
-0.16
415
2.404
0.16
259
2403
-0.16
207
129
9.615
0.16
64
9615
-0.16
51
64
19.531
1.73
31
19230
-0.16
25
SPBRG
value
SPBRG
value
SPBRG
value
(decimal)
57.6
58.140
0.94
42
56.818
-1.36
21
56.818
-1.36
10
55555
3.55
8
115.2
113.636
-1.36
21
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
0.300
0.04
1.2
1.202
2.4
2.404
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
832
300
-0.16
0.16
207
1201
0.16
103
SPBRG
value
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
415
300
-0.16
-0.16
103
1201
-0.16
51
2403
-0.16
51
2403
-0.16
25
SPBRG
value
SPBRG
value
(decimal)
207
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 = 40.000 MHz
Actual
Rate
(K)
%
Error
0.3
0.300
0.00
1.2
1.200
2.4
SPBRG
value
FOSC = 20.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
33332
0.300
0.00
0.00
8332
1.200
2.400
0.02
4165
9.6
9.606
0.06
19.2
19.193
57.6
115.2
SPBRG
value
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
16665
0.300
0.00
0.02
4165
1.200
2.400
0.02
2082
1040
9.596
-0.03
-0.03
520
19.231
57.803
0.35
172
114.943
-0.22
86
SPBRG
value
FOSC = 8.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
8332
300
-0.01
6665
0.02
2082
1200
-0.04
1665
2.402
0.06
1040
2400
-0.04
832
520
9.615
0.16
259
9615
-0.16
207
0.16
259
19.231
0.16
129
19230
-0.16
103
57.471
-0.22
86
58.140
0.94
42
57142
0.79
34
116.279
0.94
42
113.636
-1.36
21
117647
-2.12
16
(decimal)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
(K)
0.3
1.2
FOSC = 4.000 MHz
Actual
Rate
(K)
%
Error
0.300
1.200
0.01
0.04
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
3332
832
300
1201
-0.04
-0.16
SPBRG
value
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
1665
415
300
1201
-0.04
-0.16
832
207
103
SPBRG
value
SPBRG
value
(decimal)
2.4
2.404
0.16
415
2403
-0.16
207
2403
-0.16
9.6
9.615
0.16
103
9615
-0.16
51
9615
-0.16
25
19.2
19.231
0.16
51
19230
-0.16
25
19230
-0.16
12
57.6
58.824
2.12
16
55555
3.55
8
—
—
—
115.2
111.111
-3.55
8
—
—
—
—
—
—
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
18.1.2
AUTO-BAUD RATE DETECT
The enhanced USART 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 18-1) begins whenever a Start bit is received
and the ABDEN bit is set. The calculation is
self-averaging.
In the Auto-Baud Rate 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.
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 calibrating the baud rate period, the BRG registers are clocked at 1/8th the preconfigured 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
FIGURE 18-1:
BRG Value
carry occurred for 8-bit modes by checking for 00h in
the SPBRGH register. Refer to Table 18-4 for counter
clock rates to the BRG.
While the ABD sequence takes place, the USART 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.
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 USART 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 rate detection
feature.
TABLE 18-4:
BRG COUNTER CLOCK
RATES
BRG16
BRGH
BRG Counter Clock
0
0
FOSC/512
0
1
FOSC/128
1
0
FOSC/128
1
1
FOSC/32
Note:
During the ABD sequence, SPBRG and
SPBRGH are both used as a 16-bit
counter independent of BRG16 setting.
AUTOMATIC BAUD RATE CALCULATION
XXXXh
0000h
001Ch
Start
RX pin
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
RCIF bit
(Interrupt)
Read
RCREG
SPBRG
XXXXh
1Ch
SPBRGH
XXXXh
00h
Note 1:
The ABD sequence requires the USART module to be configured in Asynchronous mode and WUE = 0.
DS30491D-page 236
2003-2013 Microchip Technology Inc.
18F8680.book Page 237 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
18.2
USART Asynchronous Mode
The Asynchronous mode of operation is selected by
clearing the SYNC bit (TXSTA). In this mode, the
USART uses standard Non-Return-to-Zero (NRZ) format (one Start bit, eight or nine data bits and one Stop
bit). The most common data format is 8 bits. An on-chip
dedicated 8-bit/16-bit Baud Rate Generator can be
used to derive standard baud rate frequencies from the
oscillator.
The USART transmits and receives the LSb first. The
USART’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 and BAUDCON). 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 low-power
modes; it is available in Sleep mode only when autowake-up on sync break is enabled. When in PRI_IDLE
mode, no changes to the Baud Rate Generator values
are required; however, other low-power mode clocks
may operate at another frequency than the primary
clock. Therefore, the Baud Rate Generator values may
need to be adjusted.
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) is set. This interrupt
can be enabled/disabled by setting/clearing enable bit
TXIE (PIE1). 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), shows the
status of the TSR register. Status bit TRMT is a readonly 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.
When operating in Asynchronous mode, the USART
module consists of the following important elements:
•
•
•
•
•
•
•
Baud Rate Generator
Sampling Circuit
Asynchronous Transmitter
Asynchronous Receiver
Auto-Wake-up on Sync Break Character
12-bit Break Character Transmit
Auto-Baud Rate Detection
18.2.1
USART ASYNCHRONOUS
TRANSMITTER
The USART transmitter block diagram is shown in
Figure 18-2. 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).
2003-2013 Microchip Technology Inc.
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.
Note:
2.
3.
4.
5.
6.
7.
When BRGH and BRG16 bits are set,
SPBRGH:SPBRG must be more than ‘1’.
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) are set.
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FIGURE 18-2:
USART TRANSMIT BLOCK DIAGRAM
Data Bus
TXIF
TXREG Register
TXIE
8
MSb
RC6/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 18-3:
ASYNCHRONOUS TRANSMISSION
Write to TXREG
BRG Output
(Shift Clock)
Word 1
RC6/TX/CK
(pin)
Start bit
TRMT bit
(Transmit Shift
Reg. Empty Flag)
FIGURE 18-4:
bit 0
bit 1
bit 7/8
Stop bit
Word 1
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
1 TCY
Word 1
Transmit Shift Reg
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Write to TXREG
BRG Output
(Shift Clock)
Word 1
RC6/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.
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TABLE 18-5:
Name
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0000 000u
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111
1111 1111
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
0000 0000
0000 0000
INTCON
TXREG
TXSTA
BAUDCON
USART Transmit Register
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous transmission.
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18.2.2
USART ASYNCHRONOUS
RECEIVER
18.2.3
The receiver block diagram is shown in Figure 18-5.
The data is received on the RC7/RX/DT pin and drives
the data recovery block. The data recovery block is
actually a high-speed shifter operating at x16 times the
baud rate, whereas the main receive serial shifter operates at the bit rate or at FOSC. This mode would
typically be used in RS-232 systems.
SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
This mode would typically be used in RS-485 systems.
To set up an asynchronous reception with address
detect enable:
1.
To set up an asynchronous reception:
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..
Note:
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) are
set.
When BRGH and BRG16 bits are set,
SPBRGH:SPBRG must be more than ‘1’.
1.
FIGURE 18-5:
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.
USART RECEIVE BLOCK DIAGRAM
CREN
OERR
FERR
x64 Baud Rate CLK
BRG16
SPBRGH
SPBRG
Baud Rate Generator
64
or
16
or
4
RSR Register
MSb
Stop
(8)
7
1
LSb
0
Start
RX9
RC7/RX/DT
Pin Buffer
and Control
Data
Recovery
RX9D
RCREG Register
FIFO
SPEN
8
Interrupt
RCIF
Data Bus
RCIE
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5.
To set up an asynchronous transmission:
1.
2.
3.
4.
Initialize the SPBRG register for the appropriate
baud rate. If a high-speed baud rate is desired,
set bit BRGH (see Section 18.1 “USART Baud
Rate Generator (BRG)”).
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.
FIGURE 18-6:
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).
6.
7.
If using interrupts, ensure that the GIE and PEIE bits in
the INTCON register (INTCON) are set.
ASYNCHRONOUS RECEPTION
Start
bit
bit 0
RX (pin)
bit 1
bit 7/8 Stop
bit
Rcv Shift
Reg
Rcv Buffer Reg
Start
bit
bit 0
Stop
bit
Start
bit
bit 7/8
Stop
bit
Word 2
RCREG
Word 1
RCREG
Read Rcv
Buffer Reg
RCREG
bit 7/8
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 18-6:
Name
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
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
0000 000u
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP TMR2IP
TMR1IP
1111 1111
1111 1111
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
0000 0000
0000 0000
0000 0010
0000 0010
INTCON
RCREG
TXSTA
BAUDCON
USART Receive Register
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous reception.
SPBRGH
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18.2.4
AUTO-WAKE-UP ON SYNC BREAK
CHARACTER
During Sleep mode, all clocks to the USART are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper byte reception cannot be performed. The auto-wake-up feature allows the controller
to wake-up due to activity on the RX/DT line while the
USART is operating in Asynchronous mode.
The auto-wake-up feature is enabled by setting the
WUE bit (BAUDCON). Once set, the typical receive
sequence on RX/DT is disabled and the USART
remains in an Idle state monitoring for a wake-up event
independent of the CPU mode. A wake-up event consists of a high-to-low transition on the RX/DT line. (This
coincides with the start of a sync break or a wake-up
signal character for the LIN protocol.)
Following a wake-up event, the module generates an
RCIF interrupt. The interrupt is generated synchronously to the Q clocks in normal operating modes
(Figure 18-7) and asynchronously, if the device is in
Sleep mode (Figure 18-8). The interrupt condition is
cleared by reading the RCREG register.
The WUE bit is automatically cleared once a low-tohigh transition is observed on the RX line following the
wake-up event. At this point, the USART module is in
Idle mode and returns to normal operation. This signals
to the user that the sync break event is over.
18.2.4.1
Special Considerations Using
Auto-Wake-up
Since auto-wake-up functions by sensing rising edge
transitions on RX/DT, information with any state changes
before the Stop bit may signal a false end-of-character
FIGURE 18-7:
and cause data or framing errors. To work properly,
therefore, the initial character in the transmission must
be all ‘0’s. This can be 00h (8 bytes) for standard RS-232
devices or 000h (12 bits) for LIN bus.
Oscillator start-up time must also be considered,
especially in applications using oscillators with longer
start-up intervals (i.e., XT or HS mode). The sync break
(or wake-up signal) character must be of sufficient
length and be followed by a sufficient interval to allow
enough time for the selected oscillator to start and
provide proper initialization of the USART.
18.2.4.2
Special Considerations Using
the WUE Bit
The timing of WUE and RCIF events may cause some
confusion when it comes to determining the validity of
received data. As noted, setting the WUE bit places the
USART in an Idle mode. The wake-up event causes a
receive interrupt by setting the RCIF bit. The WUE bit
is cleared after this when a rising edge is seen on
RX/DT. The interrupt condition is then cleared by reading the RCREG register. Ordinarily, the data in RCREG
will be dummy data and should be discarded.
The fact that the WUE bit has been cleared (or is still
set) and the RCIF flag is set should not be used as an
indicator of the integrity of the data in RCREG. Users
should consider implementing a parallel method in
firmware to verify received data integrity.
To assure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process. If
a receive operation is not occurring, the WUE bit may
then be set just prior to entering the Sleep mode.
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 Q1 Q2 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
Cleared due to User Read of RCREG
Note:
The USART remains in Idle while the WUE bit is set.
FIGURE 18-8:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Auto-Cleared
Bit Set by User
WUE bit
RX/DT Line
Note 1
RCIF
Sleep Command Executed
Note 1:
2:
Sleep Ends
Cleared due to User Read of RCREG
If the wake-up event requires long oscillator warm-up time, the auto-clear of the WUE bit can occur while the stposc signal is still active.
This sequence should not depend on the presence of Q clocks.
The USART remains in Idle while the WUE bit is set.
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18.2.5
BREAK CHARACTER SEQUENCE
The enhanced USART 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 twelve
‘0’ bits and a Stop bit. The frame break character is sent
whenever the SENDB and TXEN bits (TXSTA and
TXSTA) 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 SENDB 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 18-9 for the timing of the break
character sequence.
18.2.5.1
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 USART for the desired mode.
Set the TXEN and SENDB bits to set up 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 SENDB bit is
reset by hardware. The sync character now
transmits in the preconfigured mode.
When the TXREG becomes empty, as indicated by the
TXIF, the next data byte can be written to TXREG.
18.2.6
RECEIVING A BREAK CHARACTER
The enhanced USART module can receive a break
character in two ways.
The first method forces the configuration of 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 18.2.4 “Auto-Wake-up on Sync
Break Character”. By enabling this feature, the
USART 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 rate detect feature.
For both methods, the user can set the ABD bit once
the TXIF interrupt is observed.
FIGURE 18-9:
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)
SENDB Sampled Here
Auto-Cleared
SENDB
(Transmit Shift
Reg. Empty Flag)
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18.3
USART 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) is set. The interrupt
can be enabled/disabled by setting/clearing enable bit,
TXIE (PIE1). 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). 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). In addition, enable bit, SPEN
(RCSTA), is set in order to configure the
RC6/TX/CK and RC7/RX/DT I/O pins to CK (clock) and
DT (data) lines, respectively.
While flag bit TXIF indicates the status of the TXREG
register, another bit, TRMT (TXSTA), 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 must 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 (BAUDCON); setting
SCKP sets the Idle state on CK as high, while clearing
the bit sets the Idle state as low. This option is provided
to support Microwire devices with this module.
18.3.1
To set up a synchronous master transmission:
1.
USART SYNCHRONOUS MASTER
TRANSMISSION
2.
The USART transmitter block diagram is shown in
Figure 18-2. 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).
FIGURE 18-10:
3.
4.
5.
6.
7.
8.
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) are
set.
SYNCHRONOUS TRANSMISSION
Q1 Q2 Q3Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX/DT
pin
bit 0
bit 1
bit 2
Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
bit 7
Word 1
RC6/TX/CK
pin
(SCKP = 0)
RC6/TX/CK
pin
(SCKP = 1)
Write to
TXREG Reg
Write Word 1
bit 0
bit 1
bit 7
Word 2
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.
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FIGURE 18-11:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
RC7/RX/DT pin
bit 0
bit 1
bit 2
bit 6
bit 7
RC6/TX/CK pin
Write to
TXREG Reg
TXIF bit
TRMT bit
TXEN bit
TABLE 18-7:
Name
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000
0000 0000
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111
1111 1111
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
INTCON
PIR1
TXREG
TXSTA
BAUDCON
GIE/GIEH PEIE/GIEL TMR0IE
Bit 4
USART Transmit Register
0000 0000
0000 0000
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-0 0-00
-1-0 0-00
SPBRGH
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, - = unimplemented, read as ‘0’. Shaded cells are not used for synchronous master transmission.
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PIC18F6585/8585/6680/8680
18.3.2
USART 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) are
set.
Once Synchronous mode is selected, reception is
enabled by setting either the Single Receive Enable bit,
SREN (RCSTA), or the Continuous Receive
Enable bit, CREN (RCSTA). Data is sampled on the
RC7/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 18-12:
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
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 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX/DT pin
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
RC7/TX/CK pin
(SCKP = 0)
RC7/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.
TABLE 18-8:
Name
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
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
0000 0000
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111
1111 1111
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
INTCON
RCREG
TXSTA
BAUDCON
GIE/GIEH PEIE/GIEL
USART Receive Register
0000 0000
0000 0000
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-0 0-00
-1-0 0-00
SPBRGH
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, - = unimplemented, read as ‘0’. Shaded cells are not used for synchronous master reception.
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PIC18F6585/8585/6680/8680
18.4
USART Synchronous Slave Mode
To set up a synchronous slave transmission:
1.
Synchronous Slave mode is entered by clearing bit
CSRC (TXSTA). This mode differs from the
Synchronous Master mode in that the shift clock is supplied externally at the RC6/TX/CK pin (instead of being
supplied internally in Master mode). This allows the
device to transfer or receive data while in any low-power
mode.
18.4.1
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.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON) are
set.
2.
3.
4.
5.
USART SYNCHRONOUS SLAVE
TRANSMIT
6.
The operation of the Synchronous Master and Slave
modes are identical except in the case of the Sleep
mode.
7.
8.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
a)
b)
c)
d)
e)
The first word will immediately transfer to the
TSR register and transmit.
The second word will remain in TXREG register.
Flag bit TXIF will not be set.
When the first word has been shifted out of TSR,
the TXREG register will transfer the second word
to the TSR and flag bit TXIF will now be set.
If enable bit TXIE is set, the interrupt will wake
the chip from Sleep. If the global interrupt is
enabled, the program will branch to the interrupt
vector.
TABLE 18-9:
Name
REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0000 000u
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111
1111 1111
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
0000 0000
0000 0000
INTCON
TXREG
TXSTA
BAUDCON
USART Transmit Register
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, - = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave transmission.
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PIC18F6585/8585/6680/8680
18.4.2
USART 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.
2.
3.
4.
5.
If receive is enabled by setting the CREN bit prior to
entering Sleep or any Idle mode, then a word may be
received while in this low-power mode. 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 low-power
mode. If the global interrupt is enabled, the program will
branch to the interrupt vector.
6.
7.
8.
9.
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) are
set.
TABLE 18-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
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
0000 0000
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111
1111 1111
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
INTCON
RCREG
TXSTA
BAUDCON
USART Receive Register
0000 0000
0000 0000
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-0 0-00
-1-0 0-00
SPBRGH
Baud Rate Generator Register, High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register, Low Byte
0000 0000
0000 0000
Legend:
x = unknown, - = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.
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PIC18F6585/8585/6680/8680
19.0
10-BIT ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The module has five registers:
The Analog-to-Digital (A/D) converter module has 12
inputs for the PIC18F6X8X devices and 16 inputs for
the PIC18F8X8X devices. This module allows conversion of an analog input signal to a corresponding 10-bit
digital number.
A new feature for the A/D converter is the addition of programmable acquisition time. This feature allows the user
to select a new channel for conversion and to set the
GO/DONE bit immediately. When the GO/DONE bit is
set, the selected channel is sampled for the
programmed acquisition time before a conversion is
actually started. This removes the firmware overhead
that may have been required to allow for an acquisition
(sampling) period (see Register 19-3 and Section 19.4
“Selecting the A/D Conversion Clock”).
REGISTER 19-1:
•
•
•
•
•
A/D Result High Register (ADRESH)
A/D Result Low Register (ADRESL)
A/D Control Register 0 (ADCON0)
A/D Control Register 1 (ADCON1)
A/D Control Register 2 (ADCON2)
The ADCON0 register, shown in Register 19-1,
controls the operation of the A/D module. The
ADCON1 register, shown in Register 19-2, configures
the functions of the port pins. The ADCON2 register,
shown in Register 19-3, configures the A/D clock
source, programmed acquisition time and justification.
ADCON0 REGISTER
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
CHS3
CHS2
CHS1
CHS0
GO/DONE
ADON
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5-2
CHS3:CHS0: Analog Channel Select bits
0000 = Channel 0 (AN0)
0001 = Channel 1 (AN1)
0010 = Channel 2 (AN2)
0011 = Channel 3 (AN3)
0100 = Channel 4 (AN4)
0101 = Channel 5 (AN5)
0110 = Channel 6 (AN6)
0111 = Channel 7 (AN7)
1000 = Channel 8 (AN8)
1001 = Channel 9 (AN9)
1010 = Channel 10 (AN10)
1011 = Channel 11 (AN11)
1100 = Channel 12 (AN12)(1)
1101 = Channel 13 (AN13)(1)
1110 = Channel 14 (AN14)(1)
1111 = Channel 15 (AN15)(1)
bit 1
GO/DONE: A/D Conversion Status bit
When ADON = 1:
1 = A/D conversion in progress. This bit is automatically cleared when the A/D conversion is
complete.
0 = A/D Idle
bit 0
ADON: A/D On bit
1 = A/D converter module is enabled
0 = A/D converter module is disabled and consumes no current
Note 1: These channels are only available on PIC18F8X8X devices.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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PIC18F6585/8585/6680/8680
REGISTER 19-2:
ADCON1 REGISTER
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
bit 7
bit 0
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 VCFG1:VCFG0: Voltage Reference Configuration bits
A/D VREF+
A/D VREF-
00
AVDD
AVSS
01
External VREF+
AVSS
10
AVDD
External VREF-
11
External VREF+
External VREF-
bit 3-0 PCFG3:PCFG0: A/D Port Configuration Control bits
AN15 AN14 AN13 AN12 AN11 AN10 AN9 AN8 AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
0000
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
0001
D
D
A
A
A
A
A
A
A
A
A
A
A
A
A
A
0010
D
D
D
A
A
A
A
A
A
A
A
A
A
A
A
A
0011
D
D
D
D
A
A
A
A
A
A
A
A
A
A
A
A
0100
D
D
D
D
D
A
A
A
A
A
A
A
A
A
A
A
0101
D
D
D
D
D
D
A
A
A
A
A
A
A
A
A
A
0110
D
D
D
D
D
D
D
A
A
A
A
A
A
A
A
A
0111
D
D
D
D
D
D
D
D
A
A
A
A
A
A
A
A
1000
D
D
D
D
D
D
D
D
D
A
A
A
A
A
A
A
1001
D
D
D
D
D
D
D
D
D
D
A
A
A
A
A
A
1010
D
D
D
D
D
D
D
D
D
D
D
A
A
A
A
A
1011
D
D
D
D
D
D
D
D
D
D
D
D
A
A
A
A
1100
D
D
D
D
D
D
D
D
D
D
D
D
D
A
A
A
1101
D
D
D
D
D
D
D
D
D
D
D
D
D
D
A
A
1110
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
A
1111
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
A = Analog input
D = Digital I/O
Shaded cells = Additional channels available on the PIC18F8X8X devices
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
Note:
DS30491D-page 250
x = Bit is unknown
Channels AN15 through AN12 are not available on the 68-pin devices.
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REGISTER 19-3:
ADCON2 REGISTER
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ADFM
—
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
bit 7
bit 0
bit 7
ADFM: A/D Result Format Select bit
1 = Right justified
0 = Left justified
bit 6
Unimplemented: Read as ‘0’
bit 5-3
ACQT2:ACQT0: A/D Acquisition Time Select bits
000 = 0 TAD(1)
001 = 2 TAD
010 = 4 TAD
011 = 6 TAD
100 = 8 TAD
101 = 12 TAD
110 = 16 TAD
111 = 20 TAD
bit 2-0
ADCS2:ADCS0: A/D Conversion Clock Select bits
000 = FOSC/2
001 = FOSC/8
010 = FOSC/32
011 = FRC (clock derived from A/D RC oscillator)(1)
100 = FOSC/4
101 = FOSC/16
110 = FOSC/64
111 = FRC (clock derived from A/D RC oscillator)(1)
Note 1: If the A/D FRC clock source is selected, a delay of one TCY (instruction cycle) is
added before the A/D clock starts. This allows the SLEEP instruction to be executed
before starting a conversion.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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A device Reset forces all registers to their Reset state.
This forces the A/D module to be turned off and any
conversion in progress is aborted.
The analog reference voltage is software selectable to
either the device’s positive and negative supply voltage
(AVDD and AVSS) or the voltage level on the RA3/AN3/
VREF+ and RA2/AN2/VREF- pins.
Each port pin associated with the A/D converter can be
configured as an analog input or as a digital I/O. The
ADRESH and ADRESL registers contain the result of
the A/D conversion. When the A/D conversion is complete, the result is loaded into the ADRESH/ADRESL
registers, the GO/DONE bit (ADCON0 register) is
cleared and A/D interrupt flag bit ADIF is set. The block
diagram of the A/D module is shown in Figure 19-1.
The A/D converter has a unique feature of being able
to operate while the device is in Sleep mode. To operate in Sleep, the A/D conversion clock must be derived
from the A/D’s internal RC oscillator.
The output of the sample and hold is the input into the
converter which generates the result via successive
approximation.
FIGURE 19-1:
A/D BLOCK DIAGRAM
CHS3:CHS0
1111
1110
1101
1100
1011
AN15(1)
AN14(1)
AN13(1)
AN12(1)
AN11
1010
AN10
1001
AN9
1000
AN8
0111
AN7
0110
AN6
0101
AN5
0100
AN4
VAIN
0011
(Input Voltage)
10-bit
Converter
A/D
AN3
0010
AN2
0001
VCFG1:VCFG0
AN1
0000
AN0
VDD
VREF+
Reference
Voltage
VREFVSS
Note 1: Channels AN15 through AN12 are not available on the PIC18F6X8X.
2: I/O pins have diode protection to VDD and VSS.
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The value in the ADRESH/ADRESL registers is not
modified for a Power-on Reset. The ADRESH/
ADRESL registers will contain unknown data after a
Power-on Reset.
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 an
input. To determine acquisition time, see Section 19.1
“A/D Acquisition Requirements”. After this acquisition time has elapsed, the A/D conversion can be
started. An acquisition time can be programmed to
occur between setting the GO/DONE bit and the actual
start of the conversion.
The following steps should be followed to do an A/D
conversion:
1.
2.
3.
4.
5.
Configure the A/D module:
• Configure analog pins, voltage reference and
digital I/O (ADCON1)
• Select A/D input channel (ADCON0)
• Select A/D acquisition time (ADCON2)
• Select A/D conversion clock (ADCON2)
• Turn on A/D module (ADCON0)
Configure A/D interrupt (if desired):
• Clear ADIF bit
• Set ADIE bit
• Set GIE bit
Wait the required acquisition time (if required).
Start conversion:
• Set GO/DONE bit (ADCON0 register)
Wait for A/D conversion to complete by either:
• Polling for the GO/DONE bit to be cleared
or
6.
7.
FIGURE 19-2:
• Waiting for the A/D interrupt
Read A/D Result registers (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 next acquisition starts.
ANALOG INPUT MODEL
VDD
Sampling
Switch
VT = 0.6V
Rs
RIC 1k
ANx
CPIN
5 pF
VAIN
VT = 0.6V
SS
RSS
ILEAKAGE
± 500 nA
CHOLD = 120 pF
VSS
Legend: CPIN
VT
ILEAKAGE
RIC
SS
CHOLD
RSS
= input capacitance
= threshold voltage
= leakage current at the pin due to
various junctions
= interconnect resistance
= sampling switch
= sample/hold capacitance (from DAC)
= sampling switch resistance
6V
5V
VDD 4V
3V
2V
5 6 7 8 9 10 11
Sampling Switch (k)
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19.1
A/D Acquisition Requirements
For the A/D converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 19-2. The
source impedance (RS) and the internal sampling
switch (RSS) impedance directly affect the time
required to charge the capacitor CHOLD. The sampling
switch (RSS) impedance varies over the device voltage
(VDD). The source impedance affects the offset voltage
at the analog input (due to pin leakage current). The
maximum recommended impedance for analog
sources is 2.5 k. After the analog input channel is
selected (changed), this acquisition must be done
before the conversion can be started.
Note:
19.2
When the conversion is started, the
holding capacitor is disconnected from the
input pin.
To calculate the minimum acquisition time,
Equation 19-1 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.
Example 19-1 shows the calculation of the minimum
required acquisition time, TACQ. This calculation is based
on the following application system assumptions:
CHOLD
Rs
Conversion Error
VDD
Temperature
VHOLD
EQUATION 19-1:
TACQ
=
=
Note:
When using external voltage references
with the A/D converter, the source impedance of the external voltage references
must be less than 20to obtain the specified A/D resolution. Higher reference
source impedances will increase both
offset and gain errors. Resistive voltage
dividers will not provide a sufficiently low
source impedance.
To maintain the best possible performance
in A/D conversions, external VREF inputs
should be buffered with an operational
amplifier or other low output impedance
circuit.
120 pF
2.5 k
1/2 LSb
5V Rss = 7 k
50C (system max.)
0V @ time = 0
ACQUISITION TIME
Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient
TAMP + TC + TCOFF
EQUATION 19-2:
VHOLD
or
TC
=
=
=
=
=
A/D VREF+ and VREF- References
If external voltage references are used instead of the
internal AVDD and AVSS sources, the source impedance
of the VREF+ and VREF- voltage sources must be considered. During acquisition, currents supplied by these
sources are insignificant. However, during conversion,
the A/D module sinks and sources current through the
reference sources. The effect of this current, as specified
in parameter A50, along with source impedance must be
considered to meet specified A/D resolution.
A/D MINIMUM CHARGING TIME
=
(VREF – (VREF/2048)) • (1 – e(-Tc/CHOLD(RIC + RSS + RS)))
=
-(120 pF)(1 k + RSS + RS) ln(1/2047)
EXAMPLE 19-1:
CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
TACQ
=
TAMP + TC + TCOFF
Temperature coefficient is only required for temperatures > 25C.
TACQ
=
2 s + TC + [(Temp – 25C)(0.05 s/C)]
TC
=
-CHOLD (RIC + RSS + RS) ln(1/2047)
-120 pF (1 k + 7 k + 2.5 k) ln(0.0004885)
-120 pF (10.5 k) ln(0.0004885)
-1.26 s (-7.6241)
9.61 s
TACQ
=
2 s + 9.61 s + [(50C – 25C)(0.05 s/C)]
11.61 s + 1.25 s
12.86 s
DS30491D-page 254
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19.3
Selecting and Configuring
Automatic Acquisition Time
The ADCON2 register allows the user to select an
acquisition time that occurs each time the GO/DONE
bit is set.
When the GO/DONE bit is set, sampling is stopped and
a conversion begins. The user is responsible for ensuring the required acquisition time has passed between
selecting the desired input channel and setting the
GO/DONE bit. This occurs when the ACQT2:ACQT0
bits (ADCON2) remain in their Reset state (‘000’)
and is compatible with devices that do not offer
programmable acquisition times.
If desired, the ACQT bits can be set to select a programmable acquisition time for the A/D module. When
the GO/DONE bit is set, the A/D module continues to
sample the input for the selected acquisition time, then
automatically begins a conversion. Since the acquisition time is programmed, there may be no need to wait
for an acquisition time between selecting a channel and
setting the GO/DONE bit.
In either case, when the conversion is completed, the
GO/DONE bit is cleared, the ADIF flag is set, and the
A/D begins sampling the currently selected channel
again. If an acquisition time is programmed, there is
nothing to indicate if the acquisition time has ended or
if the conversion has begun.
19.4
Selecting the A/D Conversion Clock
The A/D conversion time per bit is defined as TAD. The
A/D conversion requires 11 TAD per 10-bit conversion.
The source of the A/D conversion clock is software
selectable. There are seven possible options for TAD:
•
•
•
•
2 TOSC
8 TOSC
32 TOSC
Internal RC Oscillator
• 4 TOSC
• 16 TOSC
• 64 TOSC
For correct A/D conversions, the A/D conversion clock
(TAD) must be as short as possible but greater than the
minimum TAD (approximately 2 s, see parameter 130
for more information).
Table 19-1 shows the resultant TAD times derived from
the device operating frequencies and the A/D clock
source selected.
19.5
Configuring Analog Port Pins
The ADCON1, TRISA, TRISF and TRISH registers control the operation of the A/D port pins. The port pins
needed as analog inputs must have their corresponding
TRIS bits set (input). If the TRIS bit is cleared (output),
the digital output level (VOH or VOL) will be converted.
The A/D operation is independent of the state of the
CHS3:CHS0 bits and the TRIS bits.
Note 1: When reading the port register, all pins
configured as analog input channels will
read as cleared (a low level). Pins configured as digital inputs will convert an
analog input. Analog levels on a digitally
configured input will not affect the
conversion accuracy.
2: Analog levels on any pin defined as a digital input may cause the input buffer to
consume current out of the device’s
specification limits.
TABLE 19-1:
TAD vs. DEVICE OPERATING FREQUENCIES
AD Clock Source (TAD)
Note 1:
2:
3:
Maximum Device Frequency
Operation
ADCS2:ADCS0
PIC18FXX80/XX85
2 TOSC
000
1.25 MHz
PIC18LFXX80/XX85
666 kHz
4 TOSC
100
2.50 MHz
1.33 MHz
2.66 MHz
8 TOSC
001
5.00 MHz
16 TOSC
101
10.0 MHz
5.33 MHz
32 TOSC
010
20.0 MHz
10.65 MHz
64 TOSC
110
40.0 MHz
21.33 MHz
RC(3)
x11
1.00 MHz(1)
1.00 MHz(2)
The RC source has a typical TAD time of 4 s.
The RC source has a typical TAD time of 6 s.
For device frequencies above 1 MHz, the device must be in Sleep for the entire conversion or the A/D
accuracy may be out of specification.
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19.6
A/D Conversions
19.7
Figure 19-3 shows the operation of the A/D converter
after the GO bit has been set and the ACQT2:ACQT0
bits are cleared. A conversion is started after the following instruction to allow entry into Sleep mode before the
conversion begins.
Figure 19-4 shows the operation of the A/D converter
after the GO bit has been set, the ACQT2:ACQT0 bits
are set to ‘010’ and selecting a 4 TAD acquisition time
before the conversion starts.
Clearing the GO/DONE bit during a conversion will
abort the current conversion. The A/D Result register
pair will not be updated with the partially completed A/D
conversion sample. This means the ADRESH:ADRESL
registers will continue to contain the value of the last
completed conversion (or the last value written to the
ADRESH:ADRESL registers).
If the A/D module is not enabled (ADON is cleared), the
“special event trigger” will be ignored by the A/D
module but will still reset the Timer1 (or Timer3)
counter.
After the A/D conversion is completed or aborted, a
2 TAD wait is required before the next acquisition can
be started. After this wait, acquisition on the selected
channel is automatically started.
Note:
Use of the CCP2 Trigger
An A/D conversion can be started by the “special event
trigger” of the CCP2 module. This requires that the
CCP2M3:CCP2M0 bits (CCP2CON) 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 (or Timer3) counter will be reset to zero.
Timer1 (or Timer3) is reset to automatically repeat the
A/D acquisition period with minimal software overhead
(moving ADRESH/ADRESL to the desired location).
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).
The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
FIGURE 19-3:
A/D CONVERSION TAD CYCLES (ACQT = 000, TACQ = 0)
TCY - TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11
b4
b6
b1
b0
b7
b2
b9
b8
b3
b5
Conversion starts
Holding capacitor is disconnected from analog input (typically 100 ns)
Set GO bit
Next Q4: ADRESH/ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
FIGURE 19-4:
A/D CONVERSION TAD CYCLES (ACQT = 010, TACQ = 4 TAD)
TAD Cycles
TACQT Cycles
1
2
3
Automatic
Acquisition
Time
4
1
3
4
5
6
7
8
9
10
11
b8
b7
b6
b5
b4
b3
b2
b1
b0
Conversion starts
(Holding capacitor is disconnected)
Set GO bit
(Holding capacitor continues
acquiring input)
DS30491D-page 256
2
b9
Next Q4: ADRESH:ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is reconnected to analog input.
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TABLE 19-2:
Name
INTCON
SUMMARY OF A/D REGISTERS
Bit 7
Bit 6
Bit 5
GIE/GIEH PEIE/GIEL TMR0IE
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0000 0000
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000
PIR1
PSPIF
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
0000 0000
PIE1
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
0000 0000
0000 0000
IPR1
PSPIP
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
1111 1111
1111 1111
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
CCP2IF
-0-0 0000
-0-0 0000
PIE2
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE
CCP2IE
-0-0 0000
-0-0 0000
IPR2
—
CMIP
—
EEIP
BCLIP
LVDIP
TMR3IP
CCP2IP
-1-1 1111
-1-1 1111
uuuu uuuu
ADRESH
A/D Result Register High Byte
xxxx xxxx
ADRESL
A/D Result Register Low Byte
xxxx xxxx
uuuu uuuu
--00 0000
--00 0000
ADCON0
—
—
CHS3
CHS3
CHS1
CHS0
GO/DONE
ADON
ADCON1
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
--00 0000
--00 0000
ADCON2
ADFM
—
—
—
—
ADCS2
ADCS1
ADCS0
0--- -000
0--- -000
RA6
RA5
RA4
RA3
RA2
RA1
RA0
--xx xxxx
--uu uuuu
--11 1111
--11 1111
PORTA
—
TRISA
—
PORTF
RF7
RF6
RF5
RF4
RF3
RF2
RF1
RF0
xxxx xxxx
uuuu uuuu
LATF7
LATF6
LATF5
LATF4
LATF3
LATF2
LATF1
LATF0
xxxx xxxx
uuuu uuuu
1111 1111
1111 1111
LATF
TRISF
PORTH(1)
LATH(1)
TRISH(1)
Legend:
Note 1:
PORTA Data Direction Register
PORTF Data Direction Control Register
RH7
RH6
RH5
RH4
RH3
RH2
RH1
RH0
xxxx xxxx
uuuu uuuu
LATH7
LATH6
LATH5
LATH4
LATH3
LATH2
LATH1
LATH0
xxxx xxxx
uuuu uuuu
1111 1111
1111 1111
PORTH Data Direction Control Register
x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used for A/D conversion.
Only available on PIC18F8X8X devices.
2003-2013 Microchip Technology Inc.
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NOTES:
DS30491D-page 258
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20.0
COMPARATOR MODULE
The comparator module contains two analog
comparators. The inputs to the comparators are
multiplexed with the RF1 through RF6 pins. The onchip voltage reference (Section 21.0 “Comparator
Voltage Reference Module”) can also be an input to
the comparators.
REGISTER 20-1:
The CMCON register, shown in Register 20-1, controls
the comparator input and output multiplexers. A block
diagram of the various comparator configurations is
shown in Figure 20-1.
CMCON REGISTER
R-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
bit 7
bit 0
bit 7
C2OUT: Comparator 2 Output bit
When C2INV = 0:
1 = C2 VIN+ > C2 VIN0 = C2 VIN+ < C2 VINWhen C2INV = 1:
1 = C2 VIN+ < C2 VIN0 = C2 VIN+ > C2 VIN-
bit 6
C1OUT: Comparator 1 Output bit
When C1INV = 0:
1 = C1 VIN+ > C1 VIN0 = C1 VIN+ < C1 VINWhen C1INV = 1:
1 = C1 VIN+ < C1 VIN0 = C1 VIN+ > C1 VIN-
bit 5
C2INV: Comparator 2 Output Inversion bit
1 = C2 output inverted
0 = C2 output not inverted
bit 4
C1INV: Comparator 1 Output Inversion bit
1 = C1 output inverted
0 = C1 output not inverted
bit 3
CIS: Comparator Input Switch bit
When CM2:CM0 = 110:
1 = C1 VIN- connects to RF5/AN10
C2 VIN- connects to RF3/AN8
0 = C1 VIN- connects to RF6/AN11
C2 VIN- connects to RF4/AN9
bit 2-0
CM2:CM0: Comparator Mode bits
Figure 20-1 shows the Comparator modes and CM2:CM0 bit settings.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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20.1
Comparator Configuration
There are eight modes of operation for the comparators. The CMCON register is used to select these
modes. Figure 20-1 shows the eight possible modes.
The TRISF register controls the data direction of the
comparator pins for each mode. If the Comparator
FIGURE 20-1:
RF5/AN10
RF4/AN9
RF3/AN8
A
VIN-
A
VIN+
A
VIN-
A
A
RF5/AN10 A
Comparator interrupts should be disabled
during a Comparator mode change.
Otherwise, a false interrupt may occur.
VIN+
Comparators Off
CM2:CM0 = 111
RF6/AN11
C1
Off (Read as ‘0’)
C2
Off (Read as ‘0’)
RF3/AN8
VIN-
D
VIN+
D
VIN-
D
VIN+
A
VIN-
RF5/AN10 A
VIN+
RF6/AN11
C1
D
C1
Off (Read as ‘0’)
C2
Off (Read as ‘0’)
Two Independent Comparators with Outputs
CM2:CM0 = 011
VINVIN+
RF5/AN10
RF4/AN9
Two Independent Comparators
CM2:CM0 = 010
RF6/AN11
Note:
COMPARATOR I/O OPERATING MODES
Comparators Reset (POR Default Value)
CM2:CM0 = 000
RF6/AN11
mode is changed, the comparator output level may not
be valid for the specified mode change delay shown in
Section 27.0 “Electrical Characteristics”.
C1OUT
C1
C1OUT
C2
C2OUT
RF2/AN7/C1OUT
RF4/AN9
RF3/AN8
A
VIN-
A
VIN+
C2
RF4/AN9
C2OUT
RF3/AN8
A
VIN-
A
VIN+
RF1/AN6/C2OUT
Two Common Reference Comparators
CM2:CM0 = 100
RF6/AN11
RF5/AN10
A
VIN-
A
VIN+
A
VIN-
D
VIN+
Two Common Reference Comparators with Outputs
CM2:CM0 = 101
RF6/AN11
C1
C1OUT
RF5/AN10
A
VIN-
A
VIN+
C1
C1OUT
C2
C2OUT
RF2/AN7/C1OUT
RF4/AN9
RF3/AN8
C2
C2OUT
RF4/AN9
RF3/AN8
A
VIN-
D
VIN+
RF1/AN6/C2OUT
Four Inputs Multiplexed to Two Comparators
CM2:CM0 = 110
One Independent Comparator with Output
CM2:CM0 = 001
RF6/AN11
A
RF5/AN10 A
VINVIN+
RF6/AN11
C1
C1OUT
RF5/AN10 A
RF2/AN7/C1OUT
RF4/AN9
RF3/AN8
D
D
RF4/AN9
RF3/AN8
VINVIN+
C2
CIS = 0
CIS = 1
VINVIN+
C1
C1OUT
C2
C2OUT
A
A
CIS = 0
CIS = 1
VINVIN+
Off (Read as ‘0’)
A = Analog Input, port reads zeros always
DS30491D-page 260
A
CVREF
D = Digital Input
From VREF Module
CIS (CMCON) = Comparator Input Switch
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20.2
Comparator Operation
20.3.2
INTERNAL REFERENCE SIGNAL
A single comparator is shown in Figure 20-2, along with
the relationship between the analog input levels and
the digital output. When the analog input at VIN+ is less
than the analog input VIN-, the output of the comparator
is a digital low level. When the analog input at VIN+ is
greater than the analog input VIN-, the output of the
comparator is a digital high level. The shaded areas of
the output of the comparator in Figure 20-2 represent
the uncertainty due to input offsets and response time.
The comparator module also allows the selection of an
internally generated voltage reference for the comparators. Section 21.0 “Comparator Voltage Reference
Module” contains a detailed description of the comparator voltage reference module that provides this signal.
The internal reference signal is used when comparators
are in mode CM = 110 (Figure 20-1). In this mode,
the internal voltage reference is applied to the VIN+ pin
of both comparators.
20.3
20.4
Comparator Reference
An external or internal reference signal may be used
depending on the Comparator Operating mode. The
analog signal present at VIN- is compared to the signal
at VIN+ and the digital output of the comparator is
adjusted accordingly (Figure 20-2).
FIGURE 20-2:
VIN+
VIN-
SINGLE COMPARATOR
+
–
20.5
Output
VIN
VIN–
VV
ININ+
+
Comparator Outputs
The comparator outputs are read through the CMCON
register. These bits are read-only. The comparator
outputs may also be directly output to the RF1 and RF2
I/O pins. When enabled, multiplexors in the output path
of the RF1 and RF2 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 20-3 shows the
comparator output block diagram.
The TRISA bits will still function as an output
enable/disable for the RF1 and RF2 pins while in this
mode.
Output
Output
20.3.1
Comparator Response Time
Response time is the minimum time, after selecting a
new reference voltage or input source, before the
comparator output has 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 (Section 27.0
“Electrical Characteristics”).
EXTERNAL REFERENCE SIGNAL
When external voltage references are used, the
comparator module can be configured to have the comparators operate from the same or different reference
sources. However, threshold detector applications may
require the same reference. The reference signal must
be between VSS and VDD and can be applied to either
pin of the comparator(s).
2003-2013 Microchip Technology Inc.
The polarity of the comparator outputs can be changed
using the C2INV and C1INV bits (CMCON).
Note 1: When reading the Port register, all pins
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert an analog input according to the
Schmitt Trigger input specification.
2: Analog levels on any pin defined as a digital input may cause the input buffer to
consume more current than is specified.
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FIGURE 20-3:
COMPARATOR OUTPUT BLOCK DIAGRAM
Port pins
MULTIPLEX
+
-
CxINV
To RF1 or
RF2 pin
Bus
Data
Q
Read CMCON
Set
CMIF
bit
D
EN
Q
From
other
Comparator
D
EN
CL
Read CMCON
RESET
20.6
Comparator Interrupts
The comparator interrupt flag is set whenever there is
a change in the output value of either comparator.
Software will need to maintain information about the
status of the output bits, as read from CMCON, to
determine the actual change that occurred. The CMIF
bit (PIR registers) is the Comparator Interrupt Flag. The
CMIF bit must be reset by clearing it to ‘0’. Since it is
also possible to write a ‘1’ to this register, a simulated
interrupt may be initiated.
The CMIE bit (PIE registers) and the PEIE bit (INTCON
register) must be set to enable the interrupt. In addition,
the GIE bit must also be set. If any of these bits are
clear, the interrupt is not enabled, though the CMIF bit
will still be set if an interrupt condition occurs.
DS30491D-page 262
Note:
If a change in the CMCON register
(C1OUT or C2OUT) should occur when a
read operation is being executed (start of
the Q2 cycle), then the CMIF (PIR
registers) interrupt flag may not get set.
The user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
b)
Any read or write of CMCON will end the
mismatch condition.
Clear flag bit CMIF.
A mismatch condition will continue to set flag bit CMIF.
Reading CMCON will end the mismatch condition and
allow flag bit CMIF to be cleared.
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20.7
Comparator Operation During
Sleep
20.9
When a comparator is active and the device is placed
in Sleep mode, the comparator remains active and the
interrupt is functional if enabled. This interrupt will
wake-up the device from Sleep mode when enabled.
While the comparator is powered up, higher Sleep
currents than shown in the power-down current
specification will occur. Each operational comparator
will consume additional current as shown in the comparator specifications. To minimize power consumption
while in Sleep mode, turn off the comparators
(CM = 111) before entering Sleep. If the device
wakes up from Sleep, the contents of the CMCON
register are not affected.
20.8
Analog Input Connection
Considerations
A simplified circuit for an analog input is shown in
Figure 20-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to VDD
and VSS. The analog input, therefore, must be between
VSS and VDD. If the input voltage deviates from this
range by more than 0.6V in either direction, one of the
diodes is forward biased and a latch-up condition may
occur. A maximum source impedance of 10 k is
recommended for the analog sources. Any external
component connected to an analog input pin, such as
a capacitor or a Zener diode, should have very little
leakage current.
Effects of a Reset
A device Reset forces the CMCON register to its Reset
state, causing the comparator module to be in the
Comparator Reset mode (CM = 000). This
ensures that all potential inputs are analog inputs.
Device current is minimized when analog inputs are
present at Reset time. The comparators will be
powered down during the Reset interval.
FIGURE 20-4:
COMPARATOR ANALOG INPUT MODEL
VDD
VT = 0.6V
RS < 10k
RIC
Comparator
Input
AIN
VA
CPIN
5 pF
VT = 0.6V
ILEAKAGE
±500 nA
VSS
Legend:
CPIN
VT
ILEAKAGE
RIC
RS
VA
2003-2013 Microchip Technology Inc.
=
=
=
=
=
=
Input Capacitance
Threshold Voltage
Leakage Current at the pin due to various junctions
Interconnect Resistance
Source Impedance
Analog Voltage
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TABLE 20-1:
Name
REGISTERS ASSOCIATED WITH COMPARATOR MODULE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR
Value on
all other
Resets
CMCON
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
CVRCON
CVREN
CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
0000 0000 0000 0000
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000 0000 0000
INTCON
GIE/GIEH PEIE/GIEL TMR0IE
0000 0000 0000 0000
PIR2
—
CMIF
—
EEIF
BCLIF
LVDIF
TMR3IF
PIE2
—
CMIE
—
EEIE
BCLIE
LVDIE
TMR3IE CCP2IE -0-0 0000 -0-0 0000
TMR3IP CCP2IP -1-1 1111 -1-1 1111
IPR2
PORTF
LATF
TRISF
Legend:
CCP2IF -0-0 0000 -0-0 0000
—
CMIP
—
EEIP
BCLIP
LVDIP
RF7
RF6
RF5
RF4
RF3
RF2
RF1
RF0
xxxx xxxx uuuu uuuu
LATF7
LATF6
LATF5
LATF4
LATF3
LATF2
LATF1
LATF0
xxxx xxxx uuuu uuuu
TRISF7
TRISF6
TRISF5
TRISF4 TRISF3
TRISF2
TRISF1
TRISF0 1111 1111 1111 1111
x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are unused by the comparator module.
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21.0
COMPARATOR VOLTAGE
REFERENCE MODULE
21.1
The comparator voltage reference is a 16-tap resistor
ladder network that provides a selectable voltage
reference. The resistor ladder is segmented to provide
two ranges of CVREF values and has a power-down
function to conserve power when the reference is not
being used. The CVRCON register controls the
operation of the reference as shown in Register 21-1.
The block diagram is given in Figure 21-1.
The comparator reference supply voltage can come
from either VDD or VSS, or the external VREF+ and
VREF- that are multiplexed with RA3 and RA2. The
comparator reference supply voltage is controlled by
the CVRSS bit.
REGISTER 21-1:
Configuring the Comparator
Voltage Reference
The comparator voltage reference can output 16 distinct
voltage levels for each range. The equations used to
calculate the output of the comparator voltage reference
are as follows:
If CVRR = 1:
CVREF = (CVR/24) x CVRSRC
If CVRR = 0:
CVREF = (CVDD x 1/4) + (CVR/32) x CVRSRC
The settling time of the comparator voltage reference
must be considered when changing the CVREF output
(Section 27.0 “Electrical Characteristics”).
CVRCON REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
CVREN
CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
bit 7
bit 0
bit 7
CVREN: Comparator Voltage Reference Enable bit
1 = CVREF circuit powered on
0 = CVREF circuit powered down
bit 6
CVROE: Comparator VREF Output Enable bit(1)
1 = CVREF voltage level is also output on the RF5/AN10/C1IN+/CVREF pin
0 = CVREF voltage is disconnected from the RF5/AN10/C1IN+/CVREF pin
bit 5
CVRR: Comparator VREF Range Selection bit
1 = 0.00 CVRSRC to 0.625 CVRSRC with CVRSRC/24 step size
0 = 0.25 CVRSRC to 0.71875 CVRSRC with CVRSRC/32 step size
bit 4
CVRSS: Comparator VREF Source Selection bit
1 = Comparator reference source, CVRSRC = VREF+ – VREF0 = Comparator reference source, CVRSRC = VDD – VSS
Note:
bit 3-0
To select (VREF+ – VREF-) as the comparator voltage reference source, the voltage
reference configuration bits in the ADCON1 register (ADCON1) must also be
set to ‘11’.
CVR3:CVR0: Comparator VREF Value Selection bits (0 VR3:VR0 15)
When CVRR = 1:
CVREF = (CVR/24) (CVRSRC)
When CVRR = 0:
CVREF = 1/4 (CVRSRC) + (CVR3:CVR0/32) (CVRSRC)
Note 1: If enabled for output, RF5 must also be configured as an input by setting TRISF
to ‘1’.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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FIGURE 21-1:
VOLTAGE REFERENCE BLOCK DIAGRAM
VDD VREF+
CVRSS = 0
16 Stages
CVRSS = 1
CVREN
8R
R
R
R
R
CVRR
8R
CVRSS = 0
CVRSS = 1
CVREF
16-1 Analog Mux
VREFCVR3
(From CVRCON)
CVR0
Note: R is defined in Section 27.0 “Electrical Characteristics”.
21.2
Voltage Reference Accuracy/Error
21.4
Effects of a Reset
The full range of voltage reference cannot be realized
due to the construction of the module. The transistors
on the top and bottom of the resistor ladder network
(Figure 21-1) keep CVREF from approaching the reference source rails. The voltage reference is derived
from the reference source; therefore, the CVREF output
changes with fluctuations in that source. The tested
absolute accuracy of the voltage reference can be
found in Section 27.0 “Electrical Characteristics”.
A device Reset disables the voltage reference by
clearing bit CVREN (CVRCON). This Reset also
disconnects the reference from the RA2 pin by clearing
bit CVROE (CVRCON) and selects the highvoltage range by clearing bit CVRR (CVRCON).
The VRSS value select bits, CVRCON, are also
cleared.
21.3
The voltage reference module operates independently
of the comparator module. The output of the reference
generator may be connected to the RF5 pin if the
TRISF bit is set and the CVROE bit is set. Enabling
the voltage reference output onto the RF5 pin with an
input signal present will increase current consumption.
Connecting RF5 as a digital output with VRSS enabled
will also increase current consumption.
Operation During Sleep
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the CVRCON register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
21.5
Connection Considerations
The RF5 pin can be used as a simple D/A output with
limited drive capability. Due to the limited current drive
capability, a buffer must be used on the voltage reference output for external connections to VREF.
Figure 21-2 shows an example buffering technique.
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FIGURE 21-2:
VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
R(1)
CVREF
Module
RF5
+
–
CVREF Output
Voltage
Reference
Output
Impedance
Note 1:
TABLE 21-1:
Name
R is dependent upon the voltage reference configuration bits CVRCON and CVRCON.
REGISTERS ASSOCIATED WITH COMPARATOR VOLTAGE REFERENCE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR
Value on
all other
Resets
CVRCON
CVREN CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
0000 0000 0000 0000
CMCON
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
0000 0000 0000 0000
TRISF
TRISF7
TRISF6 TRISF5 TRISF4 TRISF3
TRISF2
TRISF1
TRISF0 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’.
Shaded cells are not used with the comparator voltage reference.
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NOTES:
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22.0
LOW-VOLTAGE DETECT
In many applications, the ability to determine if the
device voltage (VDD) is below a specified voltage level
is a desirable feature. A window of operation for the
application can be created where the application software can do “housekeeping tasks” before the device
voltage exits the valid operating range. This can be
done using the Low-Voltage Detect module.
This module is a software programmable circuitry
where a device voltage trip point can be specified.
When the voltage of the device becomes lower then the
specified point, an interrupt flag is set. If the interrupt is
enabled, the program execution will branch to the interrupt vector address and the software can then respond
to that interrupt source.
Figure 22-1 shows a possible application voltage curve
(typically for batteries). Over time, the device voltage
decreases. When the device voltage equals voltage VA,
the LVD logic generates an interrupt. This occurs at
time TA. The application software then has the time,
until the device voltage is no longer in valid operating
range, to shut down the system. Voltage point VB is the
minimum valid operating voltage specification. This
occurs at time TB. The difference, TB – TA, is the total
time for shutdown.
TYPICAL LOW-VOLTAGE DETECT APPLICATION
Voltage
FIGURE 22-1:
The Low-Voltage Detect circuitry is completely under
software control. This allows the circuitry to be “turned
off” by the software which minimizes the current
consumption for the device.
VA
VB
Legend:
VA = LVD trip point
VB = Minimum valid device
operating voltage
Time
TA
TB
The block diagram for the LVD module is shown in
Figure 22-2. A comparator uses an internally generated reference voltage as the set point. When the
selected tap output of the device voltage crosses the
set point (is lower than), the LVDIF bit is set.
Each node in the resistor divider represents a “trip
point” voltage. The “trip point” voltage is the minimum
supply voltage level at which the device can operate
before the LVD module asserts an interrupt. When the
2003-2013 Microchip Technology Inc.
supply voltage is equal to the trip point, the voltage
tapped off of the resistor array is equal to the 1.2V
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal setting the LVDIF bit. This voltage is
software programmable to any one of 16 values (see
Figure 22-2). The trip point is selected by
programming the LVDL3:LVDL0 bits (LVDCON).
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FIGURE 22-2:
LOW-VOLTAGE DETECT (LVD) BLOCK DIAGRAM
LVDIN
LVD3:LVD0
LVDCON
Register
16 to 1 MUX
VDD
Internally Generated
Reference Voltage
(Parameter #D423)
LVDEN
The LVD module has an additional feature that allows
the user to supply the trip voltage to the module from an
external source. This mode is enabled when bits
LVDL3:LVDL0 are set to ‘1111’. In this state, the comparator input is multiplexed from the external input pin,
FIGURE 22-3:
LVDIF
LVDIN (Figure 22-3). This gives users flexibility
because it allows them to configure the Low-Voltage
Detect interrupt to occur at any voltage in the valid
operating range.
LOW-VOLTAGE DETECT (LVD) WITH EXTERNAL INPUT BLOCK DIAGRAM
VDD
VDD
LVDCON
Register
16 to 1 MUX
LVD3:LVD0
LVDIN
Externally Generated
Trip Point
LVDEN
LVD
VxEN
BODEN
EN
BGAP
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22.1
Control Register
The Low-Voltage Detect Control register controls the
operation of the Low-Voltage Detect circuitry.
REGISTER 22-1:
LVDCON REGISTER
U-0
U-0
R-0
R/W-0
R/W-0
R/W-1
R/W-0
R/W-1
—
—
IRVST
LVDEN
LVDL3
LVDL2
LVDL1
LVDL0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5
IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the Low-Voltage Detect logic will generate the interrupt flag at the specified
voltage range
0 = Indicates that the Low-Voltage Detect logic will not generate the interrupt flag at the
specified voltage range and the LVD interrupt should not be enabled
bit 4
LVDEN: Low-Voltage Detect Power Enable bit
1 = Enables LVD, powers up LVD circuit
0 = Disables LVD, powers down LVD circuit
bit 3-0
LVDL3:LVDL0: Low-Voltage Detection Limit bits
1111 = External analog input is used (input comes from the LVDIN pin)
1110 = 4.5V-4.77V
1101 = 4.2V-4.45V
1100 = 4.0V-4.24V
1011 = 3.8V-4.03V
1010 = 3.6V-3.82V
1001 = 3.5V-3.71V
1000 = 3.3V-3.50V
0111 = 3.0V-3.18V
0110 = 2.8V-2.97V
0101 = 2.7V-2.86V
0100 = 2.5V-2.65V
0011 = 2.4V-2.54V
0010 = 2.2V-2.33V
0001 = 2.0V-2.12V
0000 = Reserved
Note:
LVDL3:LVDL0 modes which result in a trip point below the valid operating voltage
of the device are not tested.
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
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x = Bit is unknown
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22.2
Operation
The following steps are needed to set up the LVD
module:
Depending on the power source for the device voltage,
the voltage normally decreases relatively slowly. This
means that the LVD module does not need to be
constantly operating. To decrease the current requirements, the LVD circuitry only needs to be enabled for
short periods where the voltage is checked. After doing
the check, the LVD module may be disabled.
1.
2.
3.
Each time that the LVD module is enabled, the circuitry
requires some time to stabilize. After the circuitry has
stabilized, all status flags may be cleared. The module
will then indicate the proper state of the system.
4.
5.
6.
Write the value to the LVDL3:LVDL0 bits
(LVDCON register) which selects the desired
LVD trip point.
Ensure that LVD interrupts are disabled (the
LVDIE bit is cleared or the GIE bit is cleared).
Enable the LVD module (set the LVDEN bit in
the LVDCON register).
Wait for the LVD module to stabilize (the IRVST
bit to become set).
Clear the LVD interrupt flag which may have
falsely become set until the LVD module has
stabilized (clear the LVDIF bit).
Enable the LVD interrupt (set the LVDIE and the
GIE bits).
Figure 22-4 shows typical waveforms that the LVD
module may be used to detect.
FIGURE 22-4:
LOW-VOLTAGE DETECT WAVEFORMS
CASE 1:
LVDIF may not be set
VDD
VLVD
LVDIF
Enable LVD
Internally Generated
Reference Stable
TIVRST
LVDIF cleared in software
CASE 2:
VDD
VLVD
LVDIF
Enable LVD
Internally Generated
Reference Stable
TIVRST
LVDIF cleared in software
LVDIF cleared in software,
LVDIF remains set since LVD condition still exists
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22.2.1
REFERENCE VOLTAGE SET POINT
The internal reference voltage of the LVD module,
specified in electrical specification parameter #D423,
may be used by other internal circuitry (the Programmable Brown-out Reset). If these circuits are disabled
(lower current consumption), the reference voltage
circuit requires a time to become stable before a lowvoltage condition can be reliably detected. This time is
invariant of system clock speed. This start-up time is
specified in electrical specification parameter #36. The
low-voltage interrupt flag will not be enabled until a
stable reference voltage is reached. Refer to the
waveform in Figure 22-4.
22.2.2
22.3
Operation During Sleep
When enabled, the LVD circuitry continues to operate
during Sleep. If the device voltage crosses the trip
point, the LVDIF bit will be set and the device will
wake-up from Sleep. Device execution will continue
from the interrupt vector address if interrupts have
been globally enabled.
22.4
Effects of a Reset
A device Reset forces all registers to their Reset state.
This forces the LVD module to be turned off.
CURRENT CONSUMPTION
When the module is enabled, the LVD comparator and
voltage divider are enabled and will consume static current. The voltage divider can be tapped from multiple
places in the resistor array. Total current consumption,
when enabled, is specified in electrical specification
parameter #D022B.
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NOTES:
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23.0
ECAN MODULE
PIC18F6585/8585/6680/8680 devices contain an
Enhanced Controller Area Network (ECAN) module.
The ECAN module is fully backward compatible with
the CAN module available in PIC18CXX8 and
PIC18FXX8 devices.
The Controller Area Network (CAN) module is a serial
interface which is useful for communicating with other
peripherals or microcontroller devices. This interface,
or protocol, was designed to allow communications
within noisy environments.
The ECAN module is a communication controller,
implementing the CAN 2.0A or B protocol as defined in
the BOSCH specification. The module will support
CAN 1.2, CAN 2.0A, CAN 2.0B Passive and CAN 2.0B
Active versions of the protocol. The module implementation is a full CAN system; however, the CAN specification is not covered within this data sheet. Refer to the
BOSCH CAN specification for further details.
The module features are as follows:
• Implementation of the CAN protocol CAN 1.2,
CAN 2.0A and CAN 2.0B
• DeviceNetTM data bytes filter support
• Standard and extended data frames
• 0-8 bytes data length
• Programmable bit rate up to 1 Mbit/sec
• Fully backward compatible with PIC18XX8 CAN
module
• Three modes of operation:
- Mode 0 – Legacy mode
- Mode 1 – Enhanced Legacy mode with
DeviceNet support
- Mode 2 – FIFO mode with DeviceNet support
• Support for remote frames with automated handling
• Double-buffered receiver with two prioritized
received message storage buffers
• Six buffers programmable as RX and TX
message buffers
• 16 full (standard/extended identifier) acceptance
filters that can be linked to one of four masks
• Two full acceptance filter masks that can be
assigned to any filter
• One full acceptance filter that can be used as either
an acceptance filter or acceptance filter mask
• Three dedicated transmit buffers with application
specified prioritization and abort capability
• Programmable wake-up functionality with
integrated low-pass filter
• Programmable Loopback mode supports self-test
operation
• Signaling via interrupt capabilities for all CAN
receiver and transmitter error states
• Programmable clock source
• Programmable link to timer module for
time-stamping and network synchronization
• Low-Power Sleep mode
2003-2013 Microchip Technology Inc.
23.1
Module Overview
The CAN bus module consists of a protocol engine and
message buffering and control. The CAN protocol
engine automatically handles all functions for receiving
and transmitting messages on the CAN bus. Messages
are transmitted by first loading the appropriate data
registers. Status and errors can be checked by reading
the appropriate registers. Any message detected on
the CAN bus is checked for errors and then matched
against filters to see if it should be received and stored
in one of the two receive registers.
The CAN module supports the following frame types:
•
•
•
•
•
•
Standard Data Frame
Extended Data Frame
Remote Frame
Error Frame
Overload Frame Reception
Interframe Space Generation/Detection
The CAN module uses the RG0/CANTX1,
RG1/CANTX2 and RG2/CANRX pins to interface with
the CAN bus. In Normal mode, the CAN module
automatically overrides the TRISG0 and TRISG1 bits
of the CAN module pins.
23.1.1
MODULE FUNCTIONALITY
The CAN bus module consists of a protocol engine,
message buffering and control (see Figure 23-1). The
protocol engine can best be understood by defining the
types of data frames to be transmitted and received by
the module.
The following sequence illustrates the necessary initialization steps before the ECAN module can be used to
transmit or receive a message. Steps can be added or
removed depending on the requirements of the
application.
1.
2.
3.
4.
5.
Ensure that the ECAN module is in Configuration
mode.
Select ECAN Operational mode.
Set up the baud rate registers.
Set up the filter and mask registers.
Set the ECAN module to Normal mode or any
other mode required by the application logic.
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BUFFERS
16-4 to 1 muxs
MESSAGE
MSGREQ
ABTF
MLOA
TXERR
MTXBUFF
MSGREQ
ABTF
MLOA
TXERR
MTXBUFF
TXB2
MESSAGE
TXB1
MESSAGE
MSGREQ
ABTF
MLOA
TXERR
MTXBUFF
TXB0
A
c
c
e
p
t
Acceptance Filters
(RXF0 – RXF05)
MODE 0
Acceptance Filters
(RXF06 – RXF15)
MODE 1, 2
MODE 0
2 RX
Buffers
Message
Queue
Control
Transmit Byte Sequencer
VCC
Acceptance Mask
RXM0
CAN BUFFERS AND PROTOCOL ENGINE BLOCK DIAGRAM
Acceptance Mask
RXM1
FIGURE 23-1:
RXF15
Identifier
Data Field
M
A
B
Rcv Byte
MODE 1, 2
6 TX/RX
Buffers
Transmit Option
MESSAGE
BUFFERS
PROTOCOL
ENGINE
Receive
Error
Counter
Transmit
Transmit
Error
Counter
Receive
REC
TEC
Err-Pas
Bus-Off
Shift
{Transmit, Receive}
Comparator
Protocol
Finite
State
Machine
CRC
Transmit
Logic
Bit
Timing
Logic
Clock
Generator
TX
RX
Configuration
Registers
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23.2
Note:
CAN Module Registers
Not all CAN registers are available in the
Access Bank.
There are many control and data registers associated
with the CAN module. For convenience, their
descriptions have been grouped into the following
sections:
•
•
•
•
•
•
•
23.2.1
CAN CONTROL AND STATUS
REGISTERS
The registers described in this section control the
overall operation of the CAN module and show its
operational status.
Control and Status Registers
Dedicated Transmit Buffer Registers
Dedicated Receive Buffer Registers
Programmable TX/RX and Auto RTR Buffers
Baud Rate Control Registers
I/O Control Register
Interrupt Status and Control Registers
Detailed descriptions of each register and their usage
are described in the following sections.
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REGISTER 23-1:
CANCON: CAN CONTROL REGISTER
Mode 0
R/W-1
REQOP2
R/W-0
REQOP1
R/W-0
REQOP0
R/S-0
ABAT
R/W-0
WIN2
R/W-0
WIN1
R/W-0
WIN0
U-0
—
Mode 1
R/W-1
REQOP2
R/W-0
REQOP1
R/W-0
REQOP0
R/S-0
ABAT
U-0
—
U-0
—
U-0
—
U-0
—
R/W-1
REQOP2
bit 7
R/W-0
REQOP1
R/W-0
REQOP0
R/S-0
ABAT
R-0
FP3
R-0
FP2
R-0
FP1
R-0
FP0
bit 0
Mode 2
bit 7-5
REQOP2:REQOP0: Request CAN Operation Mode bits
1xx = Request Configuration mode
011 = Request Listen Only mode
010 = Request Loopback mode
001 = Request Disable mode
000 = Request Normal mode
bit 4
ABAT: Abort All Pending Transmissions bit
1 = Abort all pending transmissions (in all transmit buffers)
0 = Transmissions proceeding as normal
bit 3-1
Mode 0:
WIN2:WIN0: Window Address bits
This selects which of the CAN buffers to switch into the access bank area. This allows access
to the buffer registers from any data memory bank. After a frame has caused an interrupt, the
ICODE2:ICODE0 bits can be copied to the WIN2:WIN0 bits to select the correct buffer. See
Example 23-2 for a code example.
111 = Receive Buffer 0
110 = Receive Buffer 0
101 = Receive Buffer 1
100 = Transmit Buffer 0
011 = Transmit Buffer 1
010 = Transmit Buffer 2
001 = Receive Buffer 0
000 = Receive Buffer 0
bit 0
Unimplemented: Read as ‘0’
bit 3-0
Mode 1:
Unimplemented: Read as ‘0’
Mode 2:
FP3:FP0: FIFO Read Pointer bits
These bits point to the message buffer to be read.
0111:0000 = Message buffer to be read
1111:1000 = Reserved
Legend:
DS30491D-page 278
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
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REGISTER 23-2:
Mode 0
Mode 1, 2
CANSTAT: CAN STATUS REGISTER
R-1
R-0
R-0
OPMODE2(1) OPMODE1(1) OPMODE0(1)
R-1
R-0
R-0
R-0
R-0
R-0
R-0
U-0
—
ICODE2
ICODE1
ICODE0
—
R-0
R-0
R-0
R-0
R-0
OPMODE2(1) OPMODE1(1) OPMODE0(1) EICODE4 EICODE3 EICODE2 EICODE1 EICODE0
bit 7
bit 0
bit 7-5
OPMODE2:OPMODE0: Operation Mode Status bits(1)
111 = Reserved
110 = Reserved
101 = Reserved
100 = Configuration mode
011 = Listen Only mode
010 = Loopback mode
001 = Disable/Sleep mode
000 = Normal mode
bit 4
Mode 0:
Unimplemented: Read as ‘0’
bit 3-1
ICODE2:ICODE0: Interrupt Code bits in Mode 0
When an interrupt occurs, a prioritized coded interrupt value will be present in these bits. This
code indicates the source of the interrupt. By copying ICODE2:ICODE0 to WIN2:WIN0, it is possible to select the correct buffer to map into the Access Bank area. See Example 23-2 for a code
example.
ICODE2:ICODE0 Value
No interrupt
000
Error interrupt
001
TXB2 interrupt
010
TXB1 interrupt
011
TXB0 interrupt
100
RXB1 interrupt
101
RXB0 interrupt
110
Wake-up interrupt
111
bit 0
Unimplemented: Read as ‘0’
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-2:
bit 4-0
CANSTAT: CAN STATUS REGISTER (CONTINUED)
Mode 1,2:
EICODE4:EICODE0: Interrupt Code bits in Mode 1 and Mode 2
When an interrupt occurs, a prioritized coded interrupt value will be present in these bits. This
code indicates the source of the interrupt. Unlike ICODE bits in Mode 0, these bits may not be
copied directly to EWIN bits to map interrupted buffer to Access Bank area. If required, user
software may maintain a table in program memory to map EICODE bits to EWIN bits and access
interrupt buffer in Access Bank area.
EICODE4:EICODE0 Value
No interrupt
00000
Error interrupt
00010
TXB2 interrupt
00100
TXB1 interrupt
00110
TXB0 interrupt
01000
RXB1 interrupt
10001/10000(2)
RXB0 interrupt
10000
Wake-up interrupt
01110
RX/TX B0 interrupt
10010(2)
RX/TX B1 interrupt
10011(2)
RX/TX B2 interrupt
10100(2)
RX/TX B3 interrupt
10101(2)
RX/TX B4 interrupt
10110(2)
RX/TX B4 interrupt
10111(2)
Note 1: To achieve maximum power saving and/or able to wake-up on CAN bus activity,
switch CAN module to Disable mode before putting the device to Sleep.
2: In Mode 2, if the buffer is configured as a receiver, EICODE bits will always contain
‘10000’ upon interrupt.
DS30491D-page 280
Legend:
U = Unimplemented bit, read as ‘0’
- n = Value at POR
C = Clearable bit
R = Readable bit
x = Bit is unknown
‘1’ = Bit is set
‘0’ = Bit is cleared
W = Writable bit
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EXAMPLE 23-1:
CHANGING TO CONFIGURATION MODE
; Request Configuration mode.
MOVLW
B’10000000’
; Set to Configuration Mode.
MOVWF
CANCON
; A request to switch to Configuration mode may not be immediately honored.
; Module will wait for CAN bus to be idle before switching to Configuration Mode.
; Request for other modes such as Loopback, Disable etc. may be honored immediately.
; It is always good practice to wait and verify before continuing.
ConfigWait:
MOVF
CANSTAT, W
; Read current mode state.
ANDLW
B’10000000’
; Interested in OPMODE bits only.
TSTFSZ WREG
; Is it Configuration mode yet?
BRA
ConfigWait
; No. Continue to wait...
; Module is in Configuration mode now.
; Modify configuration registers as required.
; Switch back to Normal mode to be able to communicate.
EXAMPLE 23-2:
WIN AND ICODE BITS USAGE IN INTERRUPT SERVICE ROUTINE TO ACCESS
TX/RX BUFFERS
; Save application required context.
; Poll interrupt flags and determine source of interrupt
; This was found to be CAN interrupt
; TempCANCON and TempCANSTAT are variables defined in Access Bank low
MOVFF
CANCON, TempCANCON
; Save CANCON.WIN bits
; This is required to prevent CANCON
; from corrupting CAN buffer access
; in-progress while this interrupt
; occurred
MOVFF
CANSTAT, TempCANSTAT
; Save CANSTAT register
; This is required to make sure that
; we use same CANSTAT value rather
; than one changed by another CAN
; interrupt.
MOVF
TempCANSTAT, W
; Retrieve ICODE bits
ANDLW
B’00001110’
ADDWF
PCL, F
; Perform computed GOTO
; to corresponding interrupt cause
BRA
NoInterrupt
; 000 = No interrupt
BRA
ErrorInterrupt
; 001 = Error interrupt
BRA
TXB2Interrupt
; 010 = TXB2 interrupt
BRA
TXB1Interrupt
; 011 = TXB1 interrupt
BRA
TXB0Interrupt
; 100 = TXB0 interrupt
BRA
RXB1Interrupt
; 101 = RXB1 interrupt
BRA
RXB0Interrupt
; 110 = RXB0 interrupt
; 111 = Wake-up on interrupt
WakeupInterrupt
BCF
PIR3, WAKIF
; Clear the interrupt flag
;
; User code to handle wake-up procedure
;
;
; Continue checking for other interrupt source or return from here
…
NoInterrupt
…
; PC should never vector here. User may
; place a trap such as infinite loop or pin/port
; indication to catch this error.
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EXAMPLE 23-2:
WIN AND ICODE BITS USAGE IN INTERRUPT SERVICE ROUTINE TO ACCESS
TX/RX BUFFERS (CONTINUED)
ErrorInterrupt
BCF
PIR3, ERRIF
; Clear the interrupt flag
…
; Handle error.
RETFIE
TXB2Interrupt
BCF
PIR3, TXB2IF
; Clear the interrupt flag
GOTO
AccessBuffer
TXB1Interrupt
BCF
PIR3, TXB1IF
; Clear the interrupt flag
GOTO
AccessBuffer
TXB0Interrupt
BCF
PIR3, TXB0IF
; Clear the interrupt flag
GOTO
AccessBuffer
RXB1Interrupt
BCF
PIR3, RXB1IF
; Clear the interrupt flag
GOTO
Accessbuffer
RXB0Interrupt
BCF
PIR3, RXB0IF
; Clear the interrupt flag
GOTO
AccessBuffer
AccessBuffer
; This is either TX or RX interrupt
; Copy CANSTAT.ICODE bits to CANCON.WIN bits
MOVF
TempCANCON, W
; Clear CANCON.WIN bits before copying
; new ones.
ANDLW
B’11110001’
; Use previously saved CANCON value to
; make sure same value.
MOVWF
TempCANCON
; Copy masked value back to TempCANCON
MOVF
TempCANSTAT, W
; Retrieve ICODE bits
ANDLW
B’00001110’
; Use previously saved CANSTAT value
; to make sure same value.
IORWF
TempCANCON
; Copy ICODE bits to WIN bits.
MOVFF
TempCANCON, CANCON
; Copy the result to actual CANCON
; Access current buffer…
; User code
; Restore CANCON.WIN bits
MOVF
CANCON, W
; Preserve current non WIN bits
ANDLW
B’11110001’
IORWF
TempCANCON
; Restore original WIN bits
; Do not need to restore CANSTAT - it is read-only register.
; Return from interrupt or check for another module interrupt source
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REGISTER 23-3:
ECANCON: ENHANCED CAN CONTROL REGISTER
R/W-0
R/W-0
R/W-0
MDSEL1(1, 2) MDSEL0(1, 2) FIFOWM
R/W-1
R/W-0
R/W-0
R/W-0
R/W-0
EWIN4
EWIN3
EWIN2
EWIN1
EWIN0
bit 7
bit 0
bit 7-6
MDSEL1:MDSEL0: Mode Select bits
00 = Legacy mode (Mode 0, default)
01 = Enhanced Legacy mode (Mode 1)
10 = Enhanced FIFO mode (Mode 2)
11 = Reserved
bit 5
FIFOWM: FIFO High Water Mark bit(3)
1 = Will cause FIFO interrupt when one receive buffer remains(4)
0 = Will cause FIFO interrupt when four receive buffers remain
bit 4-0
EWIN4:EWIN0: Enhanced Window Address bits
These bits map the group of 16 banked CAN SFRs into access bank addresses 0F60-0F6Dh.
Exact group of registers to map is determined by binary value of these bits.
Mode 0:
Unimplemented: Read as ‘0’
Mode 1, 2:
00000 = Acceptance Filters 0, 1, 2 and BRGCON3, 2
00001 = Acceptance Filters 3, 4, 5 and BRGCON1, CIOCON
00010 = Acceptance Filter Masks, Error and Interrupt Control
00011 = Transmit Buffer 0
00100 = Transmit Buffer 1
00101 = Transmit Buffer 2
00110 = Acceptance Filters 6, 7, 8
00111 = Acceptance Filters 9, 10, 11
01000 = Acceptance Filters 12, 13, 14
01001 = Acceptance Filters 15
01010-01111 = Reserved
10000 = Receive Buffer 0
10001 = Receive Buffer 1
10010 = TX/RX Buffer 0
10011 = TX/RX Buffer 1
10100 = TX/RX Buffer 2
10101 = TX/RX Buffer 3
10110 = TX/RX Buffer 4
10111 = TX/RX Buffer 5
11000-11111 = Reserved
Note 1: These bits can only be changed in Configuration mode. See Register 19-2 to
change to Configuration mode.
2: A new mode takes into effect only after Configuration mode is exited.
3: This bit is used in Mode 2 only.
4: FIFO length of 4 or less will cause this bit to be set.
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
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x = Bit is unknown
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REGISTER 23-4:
Mode 0
Mode 1
Mode 2
COMSTAT: COMMUNICATION STATUS REGISTER
R/C-0
R/C-0
RXB0OVFL RXB1OVFL
U-0
—
R/C-0
RXBnOVFL
R/C-0
R/C-0
FIFOEMPTY RXBnOVFL
bit 7
R-0
TXBO
R-0
TXBP
R-0
RXBP
R-0
R-0
R-0
TXWARN RXWARN EWARN
R-0
TXB0
R-0
TXBP
R-0
RXBP
R-0
R-0
R-0
TXWARN RXWARN EWARN
R-0
R-0
R-0
TXBO
TXBP
RXBP
bit 7
Mode 0:
RXB0OVFL: Receive Buffer 0 Overflow bit
1 = Receive Buffer 0 overflowed
0 = Receive Buffer 0 has not overflowed
Mode 1:
Unimplemented: Read as ‘0’
Mode 2:
FIFOEMPTY: FIFO Not Empty bit
1 = Receive FIFO is not empty
0 = Receive FIFO is empty
bit 6
Mode 0:
RXB1OVFL: Receive Buffer 1 Overflow bit
1 = Receive Buffer 1 overflowed
0 = Receive Buffer 1 has not overflowed
Mode 1, 2:
RXBnOVFL: Receive Buffer Overflow bit
1 = Receive buffer has overflowed
0 = Receive buffer has not overflowed
bit 5
TXBO: Transmitter Bus-Off bit
1 = Transmit error counter > 255
0 = Transmit error counter 255
bit 4
TXBP: Transmitter Bus Passive bit
1 = Transmit error counter > 127
0 = Transmit error counter 127
bit 3
RXBP: Receiver Bus Passive bit
1 = Receive error counter > 127
0 = Receive error counter 127
bit 2
TXWARN: Transmitter Warning bit
1 = 127 Transmit error counter > 95
0 = Transmit error counter 95
bit 1
RXWARN: Receiver Warning bit
1 = 127 Receive error counter > 95
0 = Receive error counter 95
bit 0
EWARN: Error Warning bit
This bit is a flag of the RXWARN and TXWARN bits.
1 = The RXWARN or the TXWARN bits are set
0 = Neither the RXWARN or the TXWARN bits are set
R-0
R-0
R-0
TXWARN RXWARN EWARN
bit 0
Legend:
C = Clearable bit
R = Readable bit
- n = Value at POR ‘1’ = Bit is set
DS30491D-page 284
W = Writable bit
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
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23.2.2
DEDICATED CAN TRANSMIT
BUFFER REGISTERS
This section describes the dedicated CAN Transmit
Buffer registers and their associated control registers.
REGISTER 23-5:
Mode 0
Mode 1, 2
TXBnCON: TRANSMIT BUFFER n CONTROL REGISTERS [0 n 2]
U-0
R-0
R-0
R-0
R/W-0
U-0
R/W-0
R/W-0
—
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
R/C-0
R-0
R-0
R-0
R/W-0
U-0
R/W-0
R/W-0
TXBIF
TXABT
TXLARB
TXERR
TXREQ
—
TXPRI1
TXPRI0
bit 7
bit 0
bit 7
Mode 0:
Unimplemented: Read as ‘0’
Mode 1, 2:
TXBIF: Transmit Buffer Interrupt Flag bit
1 = Transmit buffer has completed transmission of message and may be reloaded
0 = Transmit buffer has not completed transmission of a message
bit 6
TXABT: Transmission Aborted Status bit(1)
1 = Message was aborted
0 = Message was not aborted
bit 5
TXLARB: Transmission Lost Arbitration Status bit(1)
1 = Message lost arbitration while being sent
0 = Message did not lose arbitration while being sent
bit 4
TXERR: Transmission Error Detected Status bit(1)
1 = A bus error occurred while the message was being sent
0 = A bus error did not occur while the message was being sent
bit 3
TXREQ: Transmit Request Status bit(2)
1 = Requests sending a message. Clears the TXABT, TXLARB, and TXERR bits.
0 = Automatically cleared when the message is successfully sent
bit 2
Unimplemented: Read as ‘0’
bit 1-0
TXPRI1:TXPRI0: Transmit Priority bits(3)
11 = Priority Level 3 (highest priority)
10 = Priority Level 2
01 = Priority Level 1
00 = Priority Level 0 (lowest priority)
Note:
Clearing this bit in software while the bit is set, will request a message abort.
Note 1: This bit is automatically cleared when TXREQ is set.
2: While TXREQ is set, Transmit Buffer registers remain read-only.
3: These bits define the order in which transmit buffers will be transferred. They do not
alter the CAN message identifier.
Legend:
U = Unimplemented bit, read as ‘0’
- n = Value at POR
C = Clearable bit
R = Readable bit
x = Bit is unknown
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
W = Writable bit
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REGISTER 23-6:
TXBnSIDH: TRANSMIT BUFFER n STANDARD IDENTIFIER REGISTERS,
HIGH BYTE [0 n 2]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID10:SID3: Standard Identifier bits, if EXIDE (TXBnSIDL) = 0;
Extended Identifier bits EID28:EID21, if EXIDE = 1.
Legend:
REGISTER 23-7:
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
TXBnSIDL: TRANSMIT BUFFER n STANDARD IDENTIFIER REGISTERS,
LOW BYTE [0 n 2]
R/W-x
R/W-x
R/W-x
U-0
R/W-x
U-0
R/W-x
R/W-x
SID2
SID1
SID0
—
EXIDE
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID2:SID0: Standard Identifier bits, if EXIDE (TXBnSIDL) = 0;
Extended Identifier bits EID20:EID18, if EXIDE = 1.
bit 4
Unimplemented: Read as ‘0’
bit 3
EXIDE: Extended Identifier Enable bit
1 = Message will transmit extended ID, SID10:SID0 becomes EID28:EID18
0 = Message will transmit standard ID, EID17:EID0 are ignored
bit 2
Unimplemented: Read as ‘0’
bit 1-0
EID17:EID16: Extended Identifier bits
Legend:
REGISTER 23-8:
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
TXBnEIDH: TRANSMIT BUFFER n EXTENDED IDENTIFIER REGISTERS,
HIGH BYTE [0 n 2]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID15:EID8: Extended Identifier bits (not used when transmitting standard identifier message)
Legend:
DS30491D-page 286
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
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REGISTER 23-9:
TXBnEIDL: TRANSMIT BUFFER n EXTENDED IDENTIFIER REGISTERS,
LOW BYTE [0 n 2]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID7:EID0: Extended Identifier bits (not used when transmitting standard identifier message)
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-10: TXBnDm: TRANSMIT BUFFER n DATA FIELD BYTE m REGISTERS
[0 n 2, 0 m 7]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
TXBnDm7 TXBnDm6 TXBnDm5 TXBnDm4 TXBnDm3 TXBnDm2 TXBnDm1 TXBnDm0
bit 7
bit 7-0
bit 0
TXBnDm7:TXBnDm0: Transmit Buffer n Data Field Byte m bits (where 0 n < 3 and 0 m < 8)
Each transmit buffer has an array of registers. For example, Transmit Buffer 0 has 7 registers:
TXB0D0 to TXB0D7.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-11: TXBnDLC: TRANSMIT BUFFER n DATA LENGTH CODE REGISTERS [0 n 2]
U-0
R/W-x
U-0
U-0
R/W-x
R/W-x
R/W-x
R/W-x
—
TXRTR
—
—
DLC3
DLC2
DLC1
DLC0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
TXRTR: Transmit Remote Frame Transmission Request bit
1 = Transmitted message will have TXRTR bit set
0 = Transmitted message will have TXRTR bit cleared
bit 5-4
Unimplemented: Read as ‘0’
bit 3-0
DLC3:DLC0: Data Length Code bits
1111 = Reserved
1110 = Reserved
1101 = Reserved
1100 = Reserved
1011 = Reserved
1010 = Reserved
1001 = Reserved
1000 = Data length = 8 bytes
0111 = Data length = 7 bytes
0110 = Data length = 6 bytes
0101 = Data length = 5 bytes
0100 = Data length = 4 bytes
0011 = Data length = 3 bytes
0010 = Data length = 2 bytes
0001 = Data length = 1 bytes
0000 = Data length = 0 bytes
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-12: TXERRCNT: TRANSMIT ERROR COUNT REGISTER
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
TEC7
TEC6
TEC5
TEC4
TEC3
TEC2
TEC1
TEC0
bit 7
bit 7-0
bit 0
TEC7:TEC0: Transmit Error Counter bits
This register contains a value which is derived from the rate at which errors occur. When the
error count overflows, the bus-off state occurs. When the bus has 128 occurrences of
11 consecutive recessive bits, the counter value is cleared.
Legend:
DS30491D-page 288
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
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EXAMPLE 23-3:
TRANSMITTING A CAN MESSAGE USING BANKED METHOD
; Need to transmit Standard Identifier message 123h using TXB0 buffer.
; To successfully transmit, CAN module must be either in Normal or Loopback mode.
; TXB0 buffer is not in access bank. And since we want banked method, we need to make sure
; that correct bank is selected.
BANKSEL TXB0CON
; One BANKSEL in beginning will make sure that we are
; in correct bank for rest of the buffer access.
; Now load transmit data into TXB0 buffer.
MOVLW
MY_DATA_BYTE1
; Load first data byte into buffer
MOVWF
TXB0D0
; Compiler will automatically set “BANKED” bit
; Load rest of data bytes - up to 8 bytes into TXB0 buffer.
...
; Load message identifier
MOVLW
60H
; Load SID2:SID0, EXIDE = 0
MOVWF
TXB0SIDL
MOVLW
24H
; Load SID10:SID3
MOVWF
TXB0SIDH
; No need to load TXB0EIDL:TXB0EIDH, as we are transmitting Standard Identifier Message only.
; Now that all data bytes are loaded, mark it for transmission.
MOVLW
B’00001000’
; Normal priority; Request transmission
MOVWF
TXB0CON
; If required, wait for message to get transmitted
BTFSC
TXB0CON, TXREQ
; Is it transmitted?
BRA
$-2
; No. Continue to wait...
; Message is transmitted.
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EXAMPLE 23-4:
TRANSMITTING A CAN MESSAGE USING WIN BITS
; Need to transmit Standard Identifier message 123h using TXB0 buffer.
; To successfully transmit, CAN module must be either in Normal or Loopback mode.
; TXB0 buffer is not in access bank. Use WIN bits to map it to RXB0 area.
MOVF
CANCON, W
; WIN bits are in lower 4 bits only. Read CANCON
; register to preserve all other bits. If operation
; mode is already known, there is no need to preserve
; other bits.
ANDLW
B’11110000’
; Clear WIN bits.
IORLW
B’00001000’
; Select Transmit Buffer 0
MOVWF
CANCON
; Apply the changes.
; Now TXB0 is mapped in place of RXB0. All future access to RXB0 registers will actually
; yield TXB0 register values.
; Load transmit data into TXB0 buffer.
MOVLW
MY_DATA_BYTE1
; Load first data byte into buffer
MOVWF
RXB0D0
; Access TXB0D0 via RXB0D0 address.
; Load rest of the data bytes - up to 8 bytes into “TXB0” buffer using RXB0 registers.
...
; Load message identifier
MOVLW
60H
; Load SID2:SID0, EXIDE = 0
MOVWF
RXB0SIDL
MOVLW
24H
; Load SID10:SID3
MOVWF
RXB0SIDH
; No need to load RXB0EIDL:RXB0EIDH, as we are transmitting Standard Identifier Message only.
; Now that all data bytes are loaded, mark it for transmission.
MOVLW
B’00001000’
; Normal priority; Request transmission
MOVWF
RXB0CON
; If required, wait for message to get transmitted
BTFSC
RXB0CON, TXREQ
; Is it transmitted?
BRA
$-2
; No. Continue to wait...
; Message is transmitted.
; If required, reset the WIN bits to default state.
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23.2.3
DEDICATED CAN RECEIVE
BUFFER REGISTERS
This section shows the dedicated CAN Receive Buffer
registers with their associated control registers.
REGISTER 23-13: RXB0CON: RECEIVE BUFFER 0 CONTROL REGISTER
Mode 0
Mode 1, 2
bit 7
R/C-0
RXFUL
R/W-0
RXM1
R/W-0
RXM0
U-0
—
R/C-0
RXFUL
bit 7
R/W-0
RXM1
R-0
RTRRO
R-0
FILHIT4
R-0
FILHIT3
R-0
FILHIT2
R-0
JTOFF
R-0
FILHIT0
R-0
FILHIT1
R-0
FILHIT0
bit 0
RXFUL: Receive Full Status bit
1 = Receive buffer contains a received message
0 = Receive buffer is open to receive a new message
Note:
bit 6
R-0
R/W-0
RXRTRRO RXB0DBEN
This bit is set by the CAN module upon receiving a message and must be cleared
by software after the buffer is read. As long as RXFUL is set, no new message will
be loaded and buffer will be considered full.
Mode 0:
RXM1: Receive Buffer Mode bit 1; combines with RXM0 to form RXM bits (see bit 5)
11 = Receive all messages (including those with errors); filter criteria is ignored
10 = Receive only valid messages with extended identifier; EXIDEN in RXFnSIDL must be ‘1’
01 = Receive only valid messages with standard identifier, EXIDEN in RXFnSIDL must be ‘0’
00 = Receive all valid messages as per EXIDEN bit in RXFnSIDL register
Mode 1, 2:
RXM1: Receive Buffer Mode bit
1 = Receive all messages (including those with errors); acceptance filters are ignored
0 = Receive all valid messages as per acceptance filters
bit 5
Mode 0:
RXM0: Receive Buffer Mode bit 0; combines with RXM1 to form RXM bits (see bit 6)
Mode 1, 2:
RTRRO: Remote Transmission Request bit for Received Message (read-only)
1 = A remote transmission request is received
0 = A remote transmission request is not received
bit 4
Mode 0:
Unimplemented: Read as ‘0’
Mode 1, 2:
FILHIT4: Filter Hit bit 4
This bit combines with other bits to form filter acceptance bits .
bit 3
Mode 0:
RXRTRRO: Remote Transmission Request bit for Received Message (read-only)
1 = A remote transmission request is received
0 = A remote transmission request is not received
Mode 1, 2:
FILHIT3: Filter Hit bit 3
This bit combines with other bits to form filter acceptance bits .
Legend:
U = Unimplemented bit, read as ‘0’
- n = Value at POR
C = Clearable bit
R = Readable bit
x = Bit is unknown
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
W = Writable bit
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REGISTER 23-13: RXB0CON: RECEIVE BUFFER 0 CONTROL REGISTER (CONTINUED)
bit 2
Mode 0:
RXB0DBEN: Receive Buffer 0 Double-Buffer Enable bit
1 = Receive Buffer 0 overflow will write to Receive Buffer 1
0 = No Receive Buffer 0 overflow to Receive Buffer 1
Mode 1, 2:
FILHIT2: Filter Hit bit 2
This bit combines with other bits to form filter acceptance bits .
bit 1
Mode 0:
JTOFF: Jump Table Offset bit (read-only copy of RXB0DBEN)
1 = Allows jump table offset between 6 and 7
0 = Allows jump table offset between 1 and 0
Note:
This bit allows same filter jump table for both RXB0CON and RXB1CON.
Mode 1, 2:
FILHIT1: Filter Hit bit 1
This bit combines with other bits to form filter acceptance bits .
bit 0
Mode 0:
FILHIT0: Filter Hit bit 0
This bit indicates which acceptance filter enabled the message reception into Receive Buffer 0.
1 = Acceptance Filter 1 (RXF1)
0 = Acceptance Filter 0 (RXF0)
Mode 1, 2:
FILHIT0: Filter Hit bit 0
This bit, in combination with FILHIT, indicates which acceptance filter enabled the
message reception into this receive buffer.
01111 = Acceptance Filter 15 (RXF15)
01110 = Acceptance Filter 14 (RXF14)
...
00000 = Acceptance Filter 0 (RXF0)
DS30491D-page 292
Legend:
U = Unimplemented bit, read as ‘0’
- n = Value at POR
C = Clearable bit
R = Readable bit
x = Bit is unknown
‘1’ = Bit is set
‘0’ = Bit is cleared
W = Writable bit
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REGISTER 23-14: RXB1CON: RECEIVE BUFFER 1 CONTROL REGISTER
Mode 0
Mode 1, 2
bit 7
R/C-0
RXFUL
R/W-0
RXM1
R/W-0
RXM0
U-0
—
R-0
RXRTRRO
R/W-0
FILHIT2
R-0
FILHIT1
R-0
FILHIT0
R/C-0
RXFUL
bit 7
R/W-0
RXM1
R-0
RTRRO
R-0
FILHIT4
R-0
FILHIT3
R-0
FILHIT2
R-0
FILHIT1
R-0
FILHIT0
bit 0
RXFUL: Receive Full Status bit
1 = Receive buffer contains a received message
0 = Receive buffer is open to receive a new message
Note:
This bit is set by the CAN module upon receiving a message and must be cleared by software after
the buffer is read. As long as RXFUL is set, no new message will be loaded and buffer will be
considered full.
bit 6
Mode 0:
RXM1: Receive Buffer Mode bit 1; combines with RXM0 to form RXM bits (see bit 5)
11 = Receive all messages (including those with errors); filter criteria is ignored
10 = Receive only valid messages with extended identifier; EXIDEN in RXFnSIDL must be ‘1’
01 = Receive only valid messages with standard identifier, EXIDEN in RXFnSIDL must be ‘0’
00 = Receive all valid messages as per EXIDEN bit in RXFnSIDL register
Mode 1, 2:
RXM1: Receive Buffer Mode bit
1 = Receive all messages (including those with errors); acceptance filters are ignored
0 = Receive all valid messages as per acceptance filters
bit 5
Mode 0:
RXM0: Receive Buffer Mode bit 0; combines with RXM1 to form RXM bits (see bit 6)
Mode 1, 2:
RTRRO: Remote Transmission Request bit for Received Message (read-only)
1 = A remote transmission request is received
0 = A remote transmission request is not received
bit 4
Mode 0:
Unimplemented: Read as ‘0’
Mode 1, 2:
FILHIT4: Filter Hit bit 4
This bit combines with other bits to form filter acceptance bits .
bit 3
Mode 0:
RXRTRRO: Remote Transmission Request bit for Received Message (read-only)
1 = A remote transmission request is received
0 = A remote transmission request is not received
Mode 1, 2:
FILHIT3: Filter Hit bit 3
This bit combines with other bits to form filter acceptance bits .
bit 2-0
Mode 0:
FILHIT2:FILHIT0: Filter Hit bits
These bits indicate which acceptance filter enabled the last message reception into Receive Buffer 1.
111 = Reserved
110 = Reserved
101 = Acceptance Filter 5 (RXF5)
100 = Acceptance Filter 4 (RXF4)
011 = Acceptance Filter 3 (RXF3)
010 = Acceptance Filter 2 (RXF2)
001 = Acceptance Filter 1 (RXF1), only possible when RXB0DBEN bit is set
000 = Acceptance Filter 0 (RXF0), only possible when RXB0DBEN bit is set
Mode 1, 2:
FILHIT2:FILHIT0 Filter Hit bits
These bits, in combination with FILHIT, indicate which acceptance filter enabled the message reception
into this receive buffer.
01111 = Acceptance Filter 15 (RXF15)
01110 = Acceptance Filter 14 (RXF14)
...
00000 = Acceptance Filter 0 (RXF0)
Legend:
C = Clearable bit
‘1’ = Bit is set
2003-2013 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
R = Readable bit
W = Writable bit
‘0’ = Bit is cleared
- n = Value at POR
x = Bit is unknown
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REGISTER 23-15: RXBnSIDH: RECEIVE BUFFER n STANDARD IDENTIFIER REGISTERS,
HIGH BYTE [0 n 1]
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID10:SID3: Standard Identifier bits, if EXID = 0 (RXBnSIDL);
Extended Identifier bits EID28:EID21, if EXID = 1.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-16: RXBnSIDL: RECEIVE BUFFER n STANDARD IDENTIFIER REGISTERS,
LOW BYTE [0 n 1]
R-x
R-x
R-x
R-x
R-x
U-0
R-x
R-x
SID2
SID1
SID0
SRR
EXID
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID2:SID0: Standard Identifier bits, if EXID = 0;
Extended Identifier bits EID20:EID18, if EXID = 1.
bit 4
SRR: Substitute Remote Request bit
This bit is always ‘0’ when EXID = 1 or equal to the value of RXRTRRO (RBXnCON)
when EXID = 0.
bit 3
EXID: Extended Identifier bit
1 = Received message is an extended data frame, SID10:SID0 are EID28:EID18
0 = Received message is a standard data frame
bit 2
Unimplemented: Read as ‘0’
bit 1-0
EID17:EID16: Extended Identifier bits
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-17: RXBnEIDH: RECEIVE BUFFER n EXTENDED IDENTIFIER REGISTERS,
HIGH BYTE [0 n 1]
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID15:EID8: Extended Identifier bits
Legend:
DS30491D-page 294
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
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REGISTER 23-18: RXBnEIDL: RECEIVE BUFFER n EXTENDED IDENTIFIER REGISTERS,
LOW BYTE [0 n 1]
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID7:EID0: Extended Identifier bits
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-19: RXBnDLC: RECEIVE BUFFER n DATA LENGTH CODE REGISTERS [0 n 1]
U-0
R-x
R-x
R-x
R-x
R-x
R-x
R-x
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
RXRTR: Receiver Remote Transmission Request bit
1 = Remote transfer request
0 = No remote transfer request
bit 5
RB1: Reserved bit 1
Reserved by CAN Spec and read as ‘0’.
bit 4
RB0: Reserved bit 0
Reserved by CAN Spec and read as ‘0’.
bit 3-0
DLC3:DLC0: Data Length Code bits
1111 = Invalid
1110 = Invalid
1101 = Invalid
1100 = Invalid
1011 = Invalid
1010 = Invalid
1001 = Invalid
1000 = Data length = 8 bytes
0111 = Data length = 7 bytes
0110 = Data length = 6 bytes
0101 = Data length = 5 bytes
0100 = Data length = 4 bytes
0011 = Data length = 3 bytes
0010 = Data length = 2 bytes
0001 = Data length = 1 bytes
0000 = Data length = 0 bytes
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-20: RXBnDm: RECEIVE BUFFER n DATA FIELD BYTE m REGISTERS
[0 n 1, 0 m 7]
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
RXBnDm7 RXBnDm6 RXBnDm5 RXBnDm4 RXBnDm3 RXBnDm2 RXBnDm1 RXBnDm0
bit 7
bit 7-0
bit 0
RXBnDm7:RXBnDm0: Receive Buffer n Data Field Byte m bits (where 0 n < 1 and 0 < m < 7)
Each receive buffer has an array of registers. For example, Receive Buffer 0 has 8 registers:
RXB0D0 to RXB0D7.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-21: RXERRCNT: RECEIVE ERROR COUNT REGISTER
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
REC7
REC6
REC5
REC4
REC3
REC2
REC1
REC0
bit 7
bit 7-0
bit 0
REC7:REC0: Receive Error Counter bits
This register contains the receive error value as defined by the CAN specifications.
When RXERRCNT > 127, the module will go into an error-passive state. RXERRCNT does not
have the ability to put the module in “bus-off” state.
Legend:
EXAMPLE 23-5:
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
READING A CAN MESSAGE
; Need to read a pending message from RXB0 buffer.
; To receive any message, filter, mask and RXM1:RXM0 bits in RXB0CON registers must be
; programmed correctly.
;
; Make sure that there is a message pending in RXB0.
BTFSS
RXB0CON, RXFUL
; Does RXB0 contain a message?
BRA
NoMessage
; No. Handle this situation...
; We have verified that a message is pending in RXB0 buffer.
; If this buffer can receive both Standard or Extended Identifier messages,
; identify type of message received.
BTFSS
RXB0SIDL, EXID
; Is this Extended Identifier?
BRA
StandardMessage
; No. This is Standard Identifier message.
; Yes. This is Extended Identifier message.
; Read all 29-bits of Extended Identifier message.
...
; Now read all data bytes
MOVFF
RXB0DO, MY_DATA_BYTE1
...
; Once entire message is read, mark the RXB0 that it is read and no longer FULL.
BCF
RXB0CON, RXFUL
; This will allow CAN Module to load new messages
; into this buffer.
...
DS30491D-page 296
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23.2.3.1
Programmable TX/RX and
Auto RTR Buffers
The ECAN module contains 6 message buffers that can
be programmed as transmit or receive buffers. Any of
these buffers can also be programmed to automatically
handle RTR messages.
Note:
These registers are not used in Mode 0.
REGISTER 23-22: BnCON: TX/RX BUFFER n CONTROL REGISTERS IN RECEIVE MODE
[0 n 5, TXnEN (BSEL0) = 0](1)
R/C-0
R/W-0
R-0
R-0
R-0
R-0
R-0
R-0
RXFUL
RXM1
RTRRO
FILHIT4
FILHIT3
FILHIT2
FILHIT1
FILHIT0
bit 7
bit 7
bit 0
RXFUL: Receive Full Status bit(1)
1 = Receive buffer contains a received message
0 = Receive buffer is open to receive a new message
Note:
This bit is set by the CAN module upon receiving a message and must be cleared
by software after the buffer is read. As long as RXFUL is set, no new message will
be loaded and buffer will be considered full.
bit 6
RXM1: Receive Buffer Mode bit
1 = Receive all messages including partial and invalid (acceptance filters are ignored)
0 = Receive all valid messages as per acceptance filters
bit 5
RTRRO: Read-Only Remote Transmission Request bit for Received Message
1 = Received message is a remote transmission request
0 = Received message is not a remote transmission request
bit 4-0
FILHIT4:FILHIT0: Filter Hit bits
These bits indicate which acceptance filter enabled the last message reception into this buffer.
01111 = Acceptance Filter 15 (RXF15)
01110 = Acceptance Filter 14 (RXF14)
...
00001 = Acceptance Filter 1 (RXF1)
00000 = Acceptance Filter 0 (RXF0)
Note 1: These registers are available in Mode 1 and 2 only.
Legend:
U = Unimplemented bit, read as ‘0’
- n = Value at POR
C = Clearable bit
R = Readable bit
x = Bit is unknown
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
W = Writable bit
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REGISTER 23-23: BnCON: TX/RX BUFFER n CONTROL REGISTERS IN TRANSMIT MODE
[0 n 5, TXnEN (BSEL0) = 1](1)
R/W-0
R-0
R-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
TXBIF
TXABT
TXLARB
TXERR
TXREQ
RTREN
TXPRI1
TXPRI0
bit 7
bit 0
bit 7
TXBIF: Transmit Buffer Interrupt Flag bit(1)
1 = A message is successfully transmitted
0 = No message was transmitted
bit 6
TXABT: Transmission Aborted Status bit(1)
1 = Message was aborted
0 = Message was not aborted
bit 5
TXLARB: Transmission Lost Arbitration Status bit(2)
1 = Message lost arbitration while being sent
0 = Message did not lose arbitration while being sent
bit 4
TXERR: Transmission Error Detected Status bit(2)
1 = A bus error occurred while the message was being sent
0 = A bus error did not occur while the message was being sent
bit 3
TXREQ: Transmit Request Status bit(3)
1 = Requests sending a message; clears the TXABT, TXLARB, and TXERR bits
0 = Automatically cleared when the message is successfully sent
Note:
Clearing this bit in software while the bit is set will request a message abort.
bit 2
RTREN: Automatic Remote Transmission Request Enable bit
1 = When a remote transmission request is received, TXREQ will be automatically set
0 = When a remote transmission request is received, TXREQ will be unaffected
bit 1-0
TXPRI1:TXPRI0: Transmit Priority bits(4)
11 = Priority Level 3 (highest priority)
10 = Priority Level 2
01 = Priority Level 1
00 = Priority Level 0 (lowest priority)
Note 1: These registers are available in Mode 1 and 2 only.
2: This bit is automatically cleared when TXREQ is set.
3: While TXREQ is set or transmission is in progress, transmit buffer registers remain
read-only.
4: These bits set the order in which the transmit buffer will be transferred. They do not
alter the CAN message identifier.
Legend:
DS30491D-page 298
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
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REGISTER 23-24: BnSIDH: TX/RX BUFFER n STANDARD IDENTIFIER REGISTERS,
HIGH BYTE IN RECEIVE MODE [0 n 5, TXnEN (BSEL0) = 0](1)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID10:SID3: Standard Identifier bits, if EXIDE (BnSIDL) = 0;
Extended Identifier bits EID28:EID21, if EXIDE = 1.
Note 1: These registers are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-25: BnSIDH: TX/RX BUFFER n STANDARD IDENTIFIER REGISTERS,
HIGH BYTE IN TRANSMIT MODE [0 n 5, TXnEN (BSEL0) = 1](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID10:SID3: Standard Identifier bits, if EXIDE (BnSIDL) = 0;
Extended Identifier bits EID28:EID21, if EXIDE = 1.
Note 1: These registers are available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-26: BnSIDL: TX/RX BUFFER n STANDARD IDENTIFIER REGISTERS,
LOW BYTE IN RECEIVE MODE [0 n 5, TXnEN (BSEL0) = 0](1)
R-x
R-x
R-x
R-x
R-x
U-0
R-x
R-x
SID2
SID1
SID0
SRR
EXID
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID2:SID0: Standard Identifier bits, if EXID = 0;
Extended Identifier bits EID20:EID18, if EXID = 1.
bit 4
SRR: Substitute Remote Transmission Request bit (only when EXID = 1)
1 = Remote transmission request occurred
0 = No remote transmission request occurred
bit 3
EXID: Extended Identifier Enable bit
1 = Received message is an extended identifier frame, SID10:SID0 are EID28:EID18
0 = Received message is a standard identifier frame
bit 2
Unimplemented: Read as ‘0’
bit 1-0
EID17:EID16: Extended Identifier bits
Note 1: These registers are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-27: BnSIDL: TX/RX BUFFER n STANDARD IDENTIFIER REGISTERS,
LOW BYTE IN TRANSMIT MODE [0 n 5, TXnEN (BSEL0) = 1](1)
R/W-x
R/W-x
R/W-x
U-0
R/W-x
U-0
R/W-x
R/W-x
SID2
SID1
SID0
—
EXIDE
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID2:SID0: Standard Identifier bits, if EXIDE = 0;
Extended Identifier bits EID20:EID18, if EXIDE = 1.
bit 4
Unimplemented: Read as ‘0’
bit 3
EXIDE: Extended Identifier Enable bit
1 = Received message is an extended identifier frame, SID10:SID0 are EID28:EID18
0 = Received message is a standard identifier frame
bit 2
Unimplemented: Read as ‘0’
bit 1-0
EID17:EID16: Extended Identifier bits
Note 1: These registers are available in Mode 1 and 2 only.
Legend:
DS30491D-page 300
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
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REGISTER 23-28: BnEIDH: TX/RX BUFFER n EXTENDED IDENTIFIER REGISTERS,
HIGH BYTE IN RECEIVE MODE [0 n 5, TXnEN (BSEL0) = 0](1)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID15:EID8: Extended Identifier bits
Note 1: These registers are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-29: BnEIDH: TX/RX BUFFER n EXTENDED IDENTIFIER REGISTERS,
HIGH BYTE IN TRANSMIT MODE [0 n 5, TXnEN (BSEL0) = 1](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID15:EID8: Extended Identifier bits
Note 1: These registers are available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-30: BnEIDL: TX/RX BUFFER n EXTENDED IDENTIFIER REGISTERS,
LOW BYTE IN RECEIVE MODE [0 n 5, TXnEN (BSEL) = 0](1)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID7:EID0: Extended Identifier bits
Note 1: These registers are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-31: BnEIDL: TX/RX BUFFER n EXTENDED IDENTIFIER REGISTERS,
LOW BYTE IN TRANSMIT MODE [0 n 5, TXnEN (BSEL) = 1](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID7:EID0: Extended Identifier bits
Note 1: These registers are available in Mode 1 and 2 only.
Legend:
DS30491D-page 302
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
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REGISTER 23-32: BnDm: TX/RX BUFFER n DATA FIELD BYTE m REGISTERS IN RECEIVE MODE
[0 n 5, 0 m 7, TXnEN (BSEL) = 0](1)
R-x
R-x
R-x
R-x
R-x
R-x
R-x
R-x
BnDm7
BnDm6
BnDm5
BnDm4
BnDm3
BnDm2
BnDm1
BnDm0
bit 7
bit 7-0
bit 0
BnDm7:BnDm0: Receive Buffer n Data Field Byte m bits (where 0 n < 3 and 0 < m < 8)
Each receive buffer has an array of registers. For example, Receive Buffer 0 has 7 registers:
B0D0 to B0D7.
Note 1: These registers are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-33: BnDm: TX/RX BUFFER n DATA FIELD BYTE m REGISTERS IN TRANSMIT MODE
[0 n 5, 0 m 7, TXnEN (BSEL) = 1](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
BnDm7
BnDm6
BnDm5
BnDm4
BnDm3
BnDm2
BnDm1
BnDm0
bit 7
bit 7-0
bit 0
BnDm7:BnDm0: Transmit Buffer n Data Field Byte m bits (where 0 n < 3 and 0 < m < 8)
Each transmit buffer has an array of registers. For example, Transmit Buffer 0 has 7 registers:
TXB0D0 to TXB0D7.
Note 1: These registers are available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-34: BnDLC: TX/RX BUFFER n DATA LENGTH CODE REGISTERS IN RECEIVE MODE
[0 n 5, TXnEN (BSEL) = 0](1)
U-0
R-x
R-x
R-x
R-x
R-x
R-x
R-x
—
RXRTR
RB1
RB0
DLC3
DLC2
DLC1
DLC0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
RXRTR: Receiver Remote Transmission Request bit
1 = This is a remote transmission request
0 = This is not a remote transmission request
bit 5
RB1: Reserved bit 1
Reserved by CAN Spec and read as ‘0’.
bit 4
RB0: Reserved bit 0
Reserved by CAN Spec and read as ‘0’.
bit 3-0
DLC3:DLC0: Data Length Code bits
1111 = Reserved
1110 = Reserved
1101 = Reserved
1100 = Reserved
1011 = Reserved
1010 = Reserved
1001 = Reserved
1000 = Data length = 8 bytes
0111 = Data length = 7 bytes
0110 = Data length = 6 bytes
0101 = Data length = 5 bytes
0100 = Data length = 4 bytes
0011 = Data length = 3 bytes
0010 = Data length = 2 bytes
0001 = Data length = 1 bytes
0000 = Data length = 0 bytes
Note 1: These registers are available in Mode 1 and 2 only.
Legend:
DS30491D-page 304
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
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REGISTER 23-35: BnDLC: TX/RX BUFFER n DATA LENGTH CODE REGISTERS IN TRANSMIT MODE
[0 n 5, TXnEN (BSEL) = 1](1)
U-0
R/W-x
U-0
U-0
R/W-x
R/W-x
R/W-x
R/W-x
—
TXRTR
—
—
DLC3
DLC2
DLC1
DLC0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
TXRTR: Transmitter Remote Transmission Request bit
1 = Transmitted message will have RTR bit set
0 = Transmitted message will have RTR bit cleared
bit 5-4
Unimplemented: Read as ‘0’
bit 3-0
DLC3:DLC0: Data Length Code bits
1111-1001 = Reserved
1000 = Data length = 8 bytes
0111 = Data length = 7 bytes
0110 = Data length = 6 bytes
0101 = Data length = 5 bytes
0100 = Data length = 4 bytes
0011 = Data length = 3 bytes
0010 = Data length = 2 bytes
0001 = Data length = 1 bytes
0000 = Data length = 0 bytes
Note 1: These registers are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-36: BSEL0: BUFFER SELECT REGISTER 0(1)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
U-0
U-0
B5TXEN
B4TXEN
B3TXEN
B2TXEN
B1TXEN
B0TXEN
—
—
bit 7
bit 0
bit 7-2
B5TXEN:B0TXEN: Buffer 5 to Buffer 0 Transmit Enable bit
1 = Buffer is configured in Transmit mode
0 = Buffer is configured in Receive mode
bit 1-0
Unimplemented: Read as ‘0’
Note 1: This register is available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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23.2.3.2
Message Acceptance Filters
and Masks
This subsection describes the message acceptance
filters and masks for the CAN receive buffers.
Note:
These
registers
are
Configuration mode only.
writable
in
REGISTER 23-37: RXFnSIDH: RECEIVE ACCEPTANCE FILTER n STANDARD IDENTIFIER FILTER
REGISTERS, HIGH BYTE [0 n 15](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID10:SID3: Standard Identifier Filter bits, if EXIDEN = 0;
Extended Identifier Filter bits EID28:EID21, if EXIDEN = 1.
Note 1: Registers RXF6SIDH:RXF15SIDH are available in Mode 1 and 2 only.
Legend:
R = Readable bit
- n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-38: RXFnSIDL: RECEIVE ACCEPTANCE FILTER n STANDARD IDENTIFIER FILTER
REGISTERS, LOW BYTE [0 n 15](1)
R/W-x
R/W-x
R/W-x
U-0
R/W-x
U-0
R/W-x
R/W-x
SID2
SID1
SID0
—
EXIDEN
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID2:SID0: Standard Identifier Filter bits, if EXIDEN = 0;
Extended Identifier Filter bits EID20:EID18, if EXIDEN = 1.
bit 4
Unimplemented: Read as ‘0’
bit 3
EXIDEN: Extended Identifier Filter Enable bit
1 = Filter will only accept extended ID messages
0 = Filter will only accept standard ID messages
Note:
In Mode 0, this bit must be set/cleared as required, irrespective of corresponding
mask register value.
bit 2
Unimplemented: Read as ‘0’
bit 1-0
EID17:EID16: Extended Identifier Filter bits
Note 1: Registers RXF6SIDL:RXF15SIDL are available in Mode 1 and 2 only.
Legend:
R = Readable bit
- n = Value at POR
DS30491D-page 306
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
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REGISTER 23-39: RXFnEIDH: RECEIVE ACCEPTANCE FILTER n EXTENDED IDENTIFIER
REGISTERS, HIGH BYTE [0 n 15](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID15:EID8: Extended Identifier Filter bits
Note 1: Registers RXF6EIDH:RXF15EIDH are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-40: RXFnEIDL: RECEIVE ACCEPTANCE FILTER n EXTENDED IDENTIFIER
REGISTERS, LOW BYTE [0 n 15](1)
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID7:EID0: Extended Identifier Filter bits
Note 1: Registers RXF6EIDL:RXF15EIDL are available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-41: RXMnSIDH: RECEIVE ACCEPTANCE MASK n STANDARD IDENTIFIER MASK
REGISTERS, HIGH BYTE [0 n 1]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
SID10
SID9
SID8
SID7
SID6
SID5
SID4
SID3
bit 7
bit 7-0
bit 0
SID10:SID3: Standard Identifier Mask bits, or Extended Identifier Mask bits EID28:EID21
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-42: RXMnSIDL: RECEIVE ACCEPTANCE MASK n STANDARD IDENTIFIER MASK
REGISTERS, LOW BYTE [0 n 1]
R/W-x
R/W-x
R/W-x
U-0
R/W-0
U-0
R/W-x
R/W-x
SID2
SID1
SID0
—
EXIDEN(1)
—
EID17
EID16
bit 7
bit 0
bit 7-5
SID2:SID0: Standard Identifier Mask bits, or Extended Identifier Mask bits EID20:EID18
bit 4
Unimplemented: Read as ‘0’
bit 3
Mode 0:
Unimplemented: Read as ‘0’
Mode 1, 2:
EXIDEN: Extended Identifier Filter Enable Mask bit(1)
1 = Messages selected by EXIDEN bit in RXFnSIDL will be accepted
0 = Both standard and extended identifier messages will be accepted
Note 1: This bit is available in Mode 1 and 2 only.
bit 2
Unimplemented: Read as ‘0’
bit 1-0
EID17:EID16: Extended Identifier Mask bits
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-43: RXMnEIDH: RECEIVE ACCEPTANCE MASK n EXTENDED IDENTIFIER MASK
REGISTERS, HIGH BYTE [0 n 1]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID15
EID14
EID13
EID12
EID11
EID10
EID9
EID8
bit 7
bit 7-0
bit 0
EID15:EID8: Extended Identifier Mask bits
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-44: RXMnEIDL: RECEIVE ACCEPTANCE MASK n EXTENDED IDENTIFIER MASK
REGISTERS, LOW BYTE [0 n 1]
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
R/W-x
EID7
EID6
EID5
EID4
EID3
EID2
EID1
EID0
bit 7
bit 7-0
bit 0
EID7:EID0: Extended Identifier Mask bits
Legend:
DS30491D-page 308
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
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REGISTER 23-45: SDFLC: STANDARD DATA BYTES FILTER LENGTH COUNT REGISTER(1)
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
—
FLC4
FLC3
FLC2
FLC1
FLC0
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-0
FLC4:FLC0: Filter Length Count bits
Mode 0:
Not used; forced to ‘00000’.
Mode 1, 2:
00000-10010 = 0
If DLC3:DLC0 =
If DLC3:DLC0 =
If DLC3:DLC0 =
If DLC3:DLC0 =
18 bits are available for standard data byte filter. Actual number of bits
used depends on DLC3:DLC0 bits (RXBnDLC or BnDLC if
configured as RX buffer) of message being received.
0000 No bits will be compared with incoming data bits
0001 Up to 8 data bits of RXFnEID, as determined by FLC2:FLC0, will
be compared with the corresponding number of data bits of the
incoming message
0010 Up to 16 data bits of RXFnEID, as determined by FLC3:FLC0,
will be compared with the corresponding number of data bits of the
incoming message
0011 Up to 18 data bits of RXFnEID, as determined by FLC4:FLC0,
will be compared with the corresponding number of data bits of the
incoming message
Note 1: This register is available in Mode 1 and 2 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
x = Bit is unknown
REGISTER 23-46: RXFCONn: RECEIVE FILTER CONTROL REGISTER n [0 n 1](1)
RXFCON0
RXFCON1
R/W-0
R/W-0
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
RXF7EN
RXF6EN
RXF5EN
RXF4EN
RXF3EN
RXF2EN
RXF1EN
RXF0EN
R/W-0
R/W-0
R/W-1
R/W-0
R/W-0
R/W-0
R/W-0
RXF15EN
RXF14EN RXF13EN RXF12EN RXF11EN RXF10EN RXF9EN
R/W-0
RXF8EN
bit 7
bit 7-0
bit 0
RXFnEN: Receive Filter n Enable bit
0 = Filter is disabled
1 = Filter is enabled
Note 1: This register is available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-47: RXFBCONn: RECEIVE FILTER BUFFER CONTROL REGISTER n(1)
RXFBCON0
RXFBCON1
RXFBCON2
RXFBCON3
RXFBCON4
RXFBCON5
RXFBCON6
RXFBCON7
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
F1BP_3
F1BP_2
F1BP_1
F1BP_0
F0BP_3
F0BP_2
F0BP_1
F0BP_0
R/W-0
R/W-0
R/W-0
R/W-1
R/W-0
R/W-0
R/W-0
R/W-1
F3BP_3
F3BP_2
F3BP_1
F3BP_0
F2BP_3
F2BP_2
F2BP_1
F2BP_0
R/W-0
R/W-0
R/W-0
R/W-1
R/W-0
R/W-0
R/W-0
R/W-1
F5BP_3
F5BP_2
F5BP_1
F5BP_0
F4BP_3
F4BP_2
F4BP_1
F4BP_0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
F7BP_3
F7BP_2
F7BP_1
F7BP_0
F6BP_3
F6BP_2
F6BP_1
F6BP_0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
F9BP_3
F9BP_2
F9BP_1
F9BP_0
F8BP_3
F8BP_2
F8BP_1
F8BP_0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
F11BP_3
F11BP_2
F11BP_1
R/W-0
R/W-0
F13BP_3
F13BP_2
R/W-0
R/W-0
F15BP_3
F15BP_2
R/W-0
F11BP_0 F10BP_3 F10BP_2 F10BP_1 F10BP_0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
F15BP_1 F15BP_0 F14BP_3 F14BP_2 F14BP_1 F14BP_0
bit 7
bit 7-0
R/W-0
F13BP_1 F13BP_0 F12BP_3 F12BP_2 F12BP_1 F12BP_0
bit 0
FnBP_3:FnBP_0: Filter n Buffer Pointer Nibble bits
0000 = Filter n is associated with RXB0
0001 = Filter n is associated with RXB1
0010 = Filter n is associated with B0
0011 = Filter n is associated with B1
.
.
.
0111 = Filter n is associated with B5
1111:1000 = Reserved
Note 1: This register is available in Mode 1 and 2 only.
Legend:
DS30491D-page 310
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
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REGISTER 23-48: MSEL0: MASK SELECT REGISTER 0(1)
R/W-0
R/W-1
R/W-0
R/W-1
R/W-0
R/W-0
R/W-0
R/W-0
FIL3_1
FIL3_0
FIL2_1
FIL2_0
FIL1_1
FIL1_0
FIL0_1
FIL0_0
bit 7
bit 0
bit 7-6
FIL3_1:FIL3_0: Filter 3 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 5-4
FIL2_1:FIL2_0: Filter 2 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 3-2
FIL1_1:FIL1_0: Filter 1 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 1-0
FIL0_1:FIL0_0: Filter 0 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
Note 1: This register is available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-49: MSEL1: MASK SELECT REGISTER 1(1)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-1
R/W-0
R/W-1
FIL7_1
FIL7_0
FIL6_1
FIL6_0
FIL5_1
FIL5_0
FIL4_1
FIL4_0
bit 7
bit 0
bit 7-6
FIL7_1:FIL7_0: Filter 7 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 5-4
FIL6_1:FIL6_0: Filter 6 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 3-2
FIL5_1:FIL5_0: Filter 5 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 1-0
FIL4_1:FIL4_0: Filter 4 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
Note 1: This register is available in Mode 1 and 2 only.
Legend:
DS30491D-page 312
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
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REGISTER 23-50: MSEL2: MASK SELECT REGISTER 2(1)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
FIL11_1
FIL11_0
FIL10_1
FIL10_0
FIL9_1
FIL9_0
FIL8_1
FIL8_0
bit 7
bit 0
bit 7-6
FIL11_1:FIL11_0: Filter 11 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 5-4
FIL10_1:FIL10_0: Filter 10 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 3-2
FIL9_1:FIL9_0: Filter 9 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 1-0
FIL8_1:FIL8_0: Filter 8 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
Note 1: This register is available in Mode 1 and 2 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
2003-2013 Microchip Technology Inc.
x = Bit is unknown
DS30491D-page 313
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REGISTER 23-51: MSEL3: MASK SELECT REGISTER 3(1)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
FIL15_1
FIL15_0
FIL14_1
FIL14_0
FIL13_1
FIL13_0
FIL12_1
FIL12_0
bit 7
bit 0
bit 7-6
FIL15_1:FIL15_0: Filter 15 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 5-4
FIL14_1:FIL14_0: Filter 14 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 3-2
FIL13_1:FIL13_0: Filter 13 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
bit 1-0
FIL12_1:FIL12_0: Filter 12 Select bits 1 and 0
11 = No mask
10 = Filter 15
01 = Acceptance Mask 1
00 = Acceptance Mask 0
Note 1: This register is available in Mode 1 and 2 only.
Legend:
DS30491D-page 314
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
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23.2.4
CAN BAUD RATE REGISTERS
This subsection describes the CAN Baud Rate
registers.
Note:
These
registers
are
Configuration mode only.
writable
in
REGISTER 23-52: BRGCON1: BAUD RATE CONTROL REGISTER 1
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
bit 7
bit 0
bit 7-6
SJW1:SJW0: Synchronized Jump Width bits
11 = Synchronization jump width time = 4 x TQ
10 = Synchronization jump width time = 3 x TQ
01 = Synchronization jump width time = 2 x TQ
00 = Synchronization jump width time = 1 x TQ
bit 5-0
BRP5:BRP0: Baud Rate Prescaler bits
111111 = TQ = (2 x 64)/FOSC
111110 = TQ = (2 x 63)/FOSC
.
.
.
000001 = TQ = (2 x 2)/FOSC
000000 = TQ = (2 x 1)/FOSC
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-53: BRGCON2: BAUD RATE CONTROL REGISTER 2
R/W-0
R/W-0
SEG2PHTS
SAM
R/W-0
R/W-0
R/W-0
R/W-0
SEG1PH2 SEG1PH1 SEG1PH0 PRSEG2
R/W-0
R/W-0
PRSEG1
PRSEG0
bit 7
bit 0
bit 7
SEG2PHTS: Phase Segment 2 Time Select bit
1 = Freely programmable
0 = Maximum of PHEG1 or Information Processing Time (IPT), whichever is greater
bit 6
SAM: Sample of the CAN bus Line bit
1 = Bus line is sampled three times prior to the sample point
0 = Bus line is sampled once at the sample point
bit 5-3
SEG1PH2:SEG1PH0: Phase Segment 1 bits
111 = Phase Segment 1 time = 8 x TQ
110 = Phase Segment 1 time = 7 x TQ
101 = Phase Segment 1 time = 6 x TQ
100 = Phase Segment 1 time = 5 x TQ
011 = Phase Segment 1 time = 4 x TQ
010 = Phase Segment 1 time = 3 x TQ
001 = Phase Segment 1 time = 2 x TQ
000 = Phase Segment 1 time = 1 x TQ
bit 2-0
PRSEG2:PRSEG0: Propagation Time Select bits
111 = Propagation time = 8 x TQ
110 = Propagation time = 7 x TQ
101 = Propagation time = 6 x TQ
100 = Propagation time = 5 x TQ
011 = Propagation time = 4 x TQ
010 = Propagation time = 3 x TQ
001 = Propagation time = 2 x TQ
000 = Propagation time = 1 x TQ
Legend:
DS30491D-page 316
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
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REGISTER 23-54: BRGCON3: BAUD RATE CONTROL REGISTER 3
R/W-0
R/W-0
WAKDIS WAKFIL
U-0
U-0
U-0
—
—
—
R/W-0
R/W-0
R/W-0
SEG2PH2(1) SEG2PH1(1) SEG2PH0(1)
bit 7
bit 0
bit 7
WAKDIS: Wake-up Disable bit
1 = Disable CAN bus activity wake-up feature
0 = Enable CAN bus activity wake-up feature
bit 6
WAKFIL: Selects CAN bus Line Filter for Wake-up bit
1 = Use CAN bus line filter for wake-up
0 = CAN bus line filter is not used for wake-up
bit 5-3
Unimplemented: Read as ‘0’
bit 2-0
SEG2PH2:SEG2PH0: Phase Segment 2 Time Select bits(1)
111 = Phase Segment 2 time = 8 x TQ
110 = Phase Segment 2 time = 7 x TQ
101 = Phase Segment 2 time = 6 x TQ
100 = Phase Segment 2 time = 5 x TQ
011 = Phase Segment 2 time = 4 x TQ
010 = Phase Segment 2 time = 3 x TQ
001 = Phase Segment 2 time = 2 x TQ
000 = Phase Segment 2 time = 1 x TQ
Note 1: Ignored if SEG2PHTS bit (BRGCON2) is ‘0’.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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23.2.5
CAN MODULE I/O CONTROL
REGISTER
This register controls the operation of the CAN module’s
I/O pins in relation to the rest of the microcontroller.
REGISTER 23-55: CIOCON: CAN I/O CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
U-0
U-0
U-0
U-0
TX2SRC
TX2EN
ENDRHI
CANCAP
—
—
—
—
bit 7
bit 0
bit 7
TX2SRC: CANTX2 Pin Data Source bit
1 = CANTX2 pin will output the CAN clock
0 = CANTX2 pin will output CANTX1
bit 6
TX2EN: CANTX2 Pin Enable bit
1 = CANTX2 pin will output CANTX1 or CAN clock as selected by TX2SRC bit
0 = CANTX2 pin will have digital I/O function
bit 5
ENDRHI: Enable Drive High bit(1)
1 = CANTX pin will drive VDD when recessive
0 = CANTX pin will be tri-state when recessive
bit 4
CANCAP: CAN Message Receive Capture Enable bit
1 = Enable CAN capture, CAN message receive signal replaces input on RC2/CCP1
0 = Disable CAN capture, RC2/CCP1 input to CCP1 module
bit 3-0
Unimplemented: Read as ‘0’
Note 1: Always set this bit when using differential bus to avoid signal crosstalk in CANTX
from other nearby pins.
Legend:
DS30491D-page 318
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
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23.2.6
CAN INTERRUPT REGISTERS
The registers in this section are the same as described
in Section 9.0 “Interrupts”. They are duplicated here
for convenience.
REGISTER 23-56: PIR3: PERIPHERAL INTERRUPT FLAG REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
IRXIF
WAKIF
ERRIF
TXB2IF/
TXBnIF
R/W-0
bit 7
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W-0
TXB1IF(1) TXB0IF(1)
R/W-0
R/W-0
RXB1IF/
RXBnIF
RXB0IF/
FIFOWMIF
bit 0
IRXIF: CAN Invalid Received Message Interrupt Flag bit
1 = An invalid message has occurred on the CAN bus
0 = No invalid message on CAN bus
WAKIF: CAN bus Activity Wake-up Interrupt Flag bit
1 = Activity on CAN bus has occurred
0 = No activity on CAN bus
ERRIF: CAN bus Error Interrupt Flag bit
1 = An error has occurred in the CAN module (multiple sources)
0 = No CAN module errors
When CAN is in Mode 0:
TXB2IF: CAN Transmit Buffer 2 Interrupt Flag bit
1 = Transmit Buffer 2 has completed transmission of a message and may be reloaded
0 = Transmit Buffer 2 has not completed transmission of a message
When CAN is in Mode 1 or 2:
TXBnIF: Any Transmit Buffer Interrupt Flag bit
1 = One or more transmit buffers has completed transmission of a message and may be reloaded
0 = No transmit buffer is ready for reload
TXB1IF: CAN Transmit Buffer 1 Interrupt Flag bit(1)
1 = Transmit Buffer 1 has completed transmission of a message and may be reloaded
0 = Transmit Buffer 1 has not completed transmission of a message
TXB0IF: CAN Transmit Buffer 0 Interrupt Flag bit(1)
1 = Transmit Buffer 0 has completed transmission of a message and may be reloaded
0 = Transmit Buffer 0 has not completed transmission of a message
When CAN is in Mode 0:
RXB1IF: CAN Receive Buffer 1 Interrupt Flag bit
1 = Receive Buffer 1 has received a new message
0 = Receive Buffer 1 has not received a new message
When CAN is in Mode 1 or 2:
RXBnIF: Any Receive Buffer Interrupt Flag bit
1 = One or more receive buffers has received a new message
0 = No receive buffer has received a new message
When CAN is in Mode 0:
RXB0IF: CAN Receive Buffer 0 Interrupt Flag bit
1 = Receive Buffer 0 has received a new message
0 = Receive Buffer 0 has not received a new message
When CAN is in Mode 1:
Unimplemented: Read as ‘0’
When CAN is in Mode 2:
FIFOWMIF: FIFO Watermark Interrupt Flag bit
1 = FIFO high watermark is reached
0 = FIFO high watermark is not reached
Note 1: In CAN Mode 1 and 2, this bit is forced to ‘0’.
Legend:
R = Readable bit
- n = Value at POR
2003-2013 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
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REGISTER 23-57: PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
IRXIE
WAKIE
ERRIE
TXB2IE/
TXBnIE
R/W-0
R/W-0
TXB1IE(1) TXB0IE(1)
R/W-0
R/W-0
RXB1IE/
RXBnIE
RXB0IE/
FIFOWMIE
bit 7
bit 0
bit 7
IRXIE: CAN Invalid Received Message Interrupt Enable bit
1 = Enable invalid message received interrupt
0 = Disable invalid message received interrupt
bit 6
WAKIE: CAN bus Activity Wake-up Interrupt Enable bit
1 = Enable bus activity wake-up interrupt
0 = Disable bus activity wake-up interrupt
bit 5
ERRIE: CAN bus Error Interrupt Enable bit
1 = Enable CAN bus error interrupt
0 = Disable CAN bus error interrupt
bit 4
When CAN is in Mode 0:
TXB2IE: CAN Transmit Buffer 2 Interrupt Enable bit
1 = Enable Transmit Buffer 2 interrupt
0 = Disable Transmit Buffer 2 interrupt
When CAN is in Mode 1 or 2:
TXBnIE: CAN Transmit Buffer Interrupts Enable bit
1 = Enable transmit buffer interrupt; individual interrupt is enabled by TXBIE and BIE0
0 = Disable all transmit buffer interrupts
bit 3
TXB1IE: CAN Transmit Buffer 1 Interrupt Enable bit(1)
1 = Enable Transmit Buffer 1 interrupt
0 = Disable Transmit Buffer 1 interrupt
bit 2
TXB0IE: CAN Transmit Buffer 0 Interrupt Enable bit(1)
1 = Enable Transmit Buffer 0 interrupt
0 = Disable Transmit Buffer 0 interrupt
bit 1
When CAN is in Mode 0:
RXB1IE: CAN Receive Buffer 1 Interrupt Enable bit
1 = Enable Receive Buffer 1 interrupt
0 = Disable Receive Buffer 1 interrupt
When CAN is in Mode 1 or 2:
RXBnIE: CAN Receive Buffer Interrupts Enable bit
1 = Enable receive buffer interrupt; individual interrupt is enabled by BIE0
0 = Disable all receive buffer interrupts
bit 0
When CAN is in Mode 0:
RXB0IE: CAN Receive Buffer 0 Interrupt Enable bit
1 = Enable Receive Buffer 0 interrupt
0 = Disable Receive Buffer 0 interrupt
When CAN is in Mode 1:
Unimplemented: Read as ‘0’
When CAN is in Mode 2:
FIFOWMIE: FIFO Watermark Interrupt Enable bit
1 = Enable FIFO watermark interrupt
0 = Disable FIFO watermark interrupt
Note 1: In CAN Mode 1 and 2, this bit is forced to ‘0’.
Legend:
DS30491D-page 320
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
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REGISTER 23-58: IPR3: PERIPHERAL INTERRUPT PRIORITY REGISTER
R/W-1
R/W-1
R/W-1
R/W-1
IRXIP
WAKIP
ERRIP
TXB2IP/
TXBnIP
R/W-1
R/W-1
TXB1IP(1) TXB0IP(1)
R/W-1
R/W-1
RXB1IP/
RXBnIP
RXB0IP/
FIFOWMIP
bit 7
bit 0
bit 7
IRXIP: CAN Invalid Received Message Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6
WAKIP: CAN bus Activity Wake-up Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
ERRIP: CAN bus Error Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4
When CAN is in Mode 0:
TXB2IP: CAN Transmit Buffer 2 Interrupt Priority bit
1 = High priority
0 = Low priority
When CAN is in Mode 1 or 2:
TXBnIP: CAN Transmit Buffer Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3
TXB1IP: CAN Transmit Buffer 1 Interrupt Priority bit(1)
1 = High priority
0 = Low priority
bit 2
TXB0IP: CAN Transmit Buffer 0 Interrupt Priority bit(1)
1 = High priority
0 = Low priority
bit 1
When CAN is in Mode 0:
RXB1IP: CAN Receive Buffer 1 Interrupt Priority bit
1 = High priority
0 = Low priority
When CAN is in Mode 1 or 2:
RXBnIP: CAN Receive Buffer Interrupts Priority bit
1 = High priority
0 = Low priority
bit 0
When CAN is in Mode 0:
RXB0IP: CAN Receive Buffer 0 Interrupt Priority bit
1 = High priority
0 = Low priority
When CAN is in Mode 1:
Unimplemented: Read as ‘0’
When CAN is in Mode 2:
FIFOWMIP: FIFO Watermark Interrupt Priority bit
1 = High priority
0 = Low priority
Note 1: In CAN Mode 1 and 2, this bit is forced to ‘0’.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
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REGISTER 23-59: TXBIE: TRANSMIT BUFFERS INTERRUPT ENABLE REGISTER(1)
U-0
U-0
U-0
R/W-0
R/W-0
R/W-0
U-0
U-0
—
—
—
TXB2IE
TXB1IE
TXB0IE
—
—
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-2
TX2BIE:TXB0IE: Transmit Buffer 2-0 Interrupt Enable bit(2)
1 = Transmit buffer interrupt is enabled
0 = Transmit buffer interrupt is disabled
bit 1-0
Unimplemented: Read as ‘0’
Note 1: This register is available in Mode 1 and 2 only.
2: TXBIE in PIE3 register must be set to get an interrupt.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
REGISTER 23-60: BIE0: BUFFER INTERRUPT ENABLE REGISTER 0(1)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
B5IE
B4IE
B3IE
B2IE
B1IE
B0IE
RXB1IE
RXB0IE
bit 7
bit 0
bit 7-2
B5IE:B0IE: Programmable Transmit/Receive Buffer 5-0 Interrupt Enable bit(2)
1 = Interrupt is enabled
0 = Interrupt is disabled
bit 1-0
RXB1IE:RXB0IE: Dedicated Receive Buffer 1-0 Interrupt Enable bit(2)
1 = Interrupt is enabled
0 = Interrupt is disabled
Note 1: This register is available in Mode 1 and 2 only.
2: Either TXBIE or RXBIE in PIE3 register must be set to get an interrupt.
Legend:
DS30491D-page 322
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
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TABLE 23-1:
Address(1)
CAN CONTROLLER REGISTER MAP
Name
F7Fh
SPBRGH(3)
F7Eh
Address
Name
Address
Name
F3Fh
CANCON_RO2
CANSTAT_RO0
F3Eh
RXB1D7
F3Dh
RXB1D6
F3Ch
Address
Name
F5Fh
CANCON_RO0
F1Fh
RXM1EIDL
BAUDCON(3)
F5Eh
F7Dh
—(4)
F5Dh
CANSTAT_RO2
F1Eh
RXM1EIDH
TXB1D7
F1Dh
F7Ch
—(4)
F5Ch
RXM1SIDL
TXB1D6
F1Ch
RXM1SIDH
F7Bh
—(4)
F5Bh
RXB1D5
F3Bh
TXB1D5
F1Bh
RXM0EIDL
F7Ah
—(4)
F5Ah
RXB1D4
F3Ah
TXB1D4
F1Ah
RXM0EIDH
F79h
ECCP1DEL(3)
F59h
RXB1D3
F39h
TXB1D3
F19h
RXM0SIDL
F78h
—(4)
F58h
RXB1D2
F38h
TXB1D2
F18h
RXM0SIDH
F77h
ECANCON
F57h
RXB1D1
F37h
TXB1D1
F17h
RXF5EIDL
F76h
TXERRCNT
F56h
RXB1D0
F36h
TXB1D0
F16h
RXF5EIDH
F75h
RXERRCNT
F55h
RXB1DLC
F35h
TXB1DLC
F15h
RXF5SIDL
F74h
COMSTAT
F54h
RXB1EIDL
F34h
TXB1EIDL
F14h
RXF5SIDH
F73h
CIOCON
F53h
RXB1EIDH
F33h
TXB1EIDH
F13h
RXF4EIDL
F72h
BRGCON3
F52h
RXB1SIDL
F32h
TXB1SIDL
F12h
RXF4EIDH
F71h
BRGCON2
F51h
RXB1SIDH
F31h
TXB1SIDH
F11h
RXF4SIDL
F70h
BRGCON1
F50h
RXB1CON
F30h
TXB1CON
F10h
RXF4SIDH
F6Fh
CANCON
F4Fh CANCON_RO1(2)
F2Fh CANCON_RO3(2)
F0Fh
RXF3EIDL
F6Eh
CANSTAT
F4Eh CANSTAT_RO1(2)
F2Eh CANSTAT_RO3(2)
F0Eh
RXF3EIDH
F6Dh
RXB0D7
F4Dh
TXB0D7
F2Dh
TXB2D7
F0Dh
RXF3SIDL
F6Ch
RXB0D6
F4Ch
TXB0D6
F2Ch
TXB2D6
F0Ch
RXF3SIDH
F6Bh
RXB0D5
F4Bh
TXB0D5
F2Bh
TXB2D5
F0Bh
RXF2EIDL
F6Ah
RXB0D4
F4Ah
TXB0D4
F2Ah
TXB2D4
F0Ah
RXF2EIDH
F69h
RXB0D3
F49h
TXB0D3
F29h
TXB2D3
F09h
RXF2SIDL
F68h
RXB0D2
F48h
TXB0D2
F28h
TXB2D2
F08h
RXF2SIDH
F67h
RXB0D1
F47h
TXB0D1
F27h
TXB2D1
F07h
RXF1EIDL
F66h
RXB0D0
F46h
TXB0D0
F26h
TXB2D0
F06h
RXF1EIDH
F65h
RXB0DLC
F45h
TXB0DLC
F25h
TXB2DLC
F05h
RXF1SIDL
F64h
RXB0EIDL
F44h
TXB0EIDL
F24h
TXB2EIDL
F04h
RXF1SIDH
F63h
RXB0EIDH
F43h
TXB0EIDH
F23h
TXB2EIDH
F03h
RXF0EIDL
F62h
RXB0SIDL
F42h
TXB0SIDL
F22h
TXB2SIDL
F02h
RXF0EIDH
F61h
RXB0SIDH
F41h
TXB0SIDH
F21h
TXB2SIDH
F01h
RXF0SIDL
F60h
RXB0CON
F40h
TXB0CON
F20h
TXB2CON
F00h
RXF0SIDH
Note 1:
2:
3:
4:
Shaded registers are available in Access Bank low area while the rest are available in Bank 15.
CANSTAT register is repeated in these locations to simplify application firmware. Unique names are given for
each instance of the controller register due to the Microchip header file requirement.
These registers are not CAN registers.
Unimplemented registers are read as ‘0’.
2003-2013 Microchip Technology Inc.
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TABLE 23-1:
CAN CONTROLLER REGISTER MAP (CONTINUED)
Address(1)
Name
Address
Name
Address
Name
Address
Name
EFFh
—(4)
EDFh
—(4)
EBFh
—(4)
E9Fh
—(4)
EFEh
—(4)
EDEh
—(4)
EBEh
—(4)
E9Eh
—(4)
EFDh
—
(4)
EDDh
—
(4)
EBDh
—
(4)
E9Dh
—(4)
EFCh
—(4)
EDCh
—(4)
EBCh
—(4)
E9Ch
—(4)
EFBh
—
(4)
EDBh
—
(4)
EBBh
—
(4)
E9Bh
—(4)
EFAh
—
(4)
EDAh
—
(4)
EBAh
—
(4)
E9Ah
—(4)
EF9h
—(4)
ED9h
—(4)
EB9h
—(4)
E99h
—(4)
EF8h
—(4)
ED8h
—(4)
EB8h
—(4)
E98h
—(4)
EF7h
—(4)
ED7h
—(4)
EB7h
—(4)
E97h
—(4)
EF6h
—(4)
ED6h
—(4)
EB6h
—(4)
E96h
—(4)
EF5h
—
(4)
ED5h
—
(4)
EB5h
—
(4)
E95h
—(4)
EF4h
—
(4)
ED4h
—
(4)
EB4h
—
(4)
E94h
—(4)
EF3h
—(4)
ED3h
—(4)
EB3h
—(4)
E93h
—(4)
EF2h
—
(4)
ED2h
—
(4)
EB2h
—
(4)
E92h
—(4)
EF1h
—(4)
ED1h
—(4)
EB1h
—(4)
E91h
—(4)
EF0h
—(4)
ED0h
—(4)
EB0h
—(4)
E90h
—(4)
EEFh
—(4)
ECFh
—(4)
EAFh
—(4)
E8Fh
—(4)
EEEh
—
(4)
ECEh
—
(4)
EAEh
—
(4)
E8Eh
—(4)
EEDh
—(4)
ECDh
—(4)
EADh
—(4)
E8Dh
—(4)
EECh
—
(4)
ECCh
—
(4)
EACh
—
(4)
E8Ch
—(4)
EEBh
—
(4)
ECBh
—
(4)
EABh
—
(4)
E8Bh
—(4)
EEAh
—(4)
ECAh
—(4)
EAAh
—(4)
E8Ah
—(4)
EE9h
—(4)
EC9h
—(4)
EA9h
—(4)
E89h
—(4)
EE8h
—(4)
EC8h
—(4)
EA8h
—(4)
E88h
—(4)
EE7h
—(4)
EC7h
—(4)
EA7h
—(4)
E87h
—(4)
EE6h
—
(4)
EC6h
—
(4)
EA6h
—
(4)
E86h
—(4)
EE5h
—
(4)
EC5h
—
(4)
EA5h
—
(4)
E85h
—(4)
EE4h
—(4)
EC4h
—(4)
EA4h
—(4)
E84h
—(4)
EE3h
—
(4)
EC3h
—
(4)
EA3h
—
(4)
E83h
—(4)
EE2h
—
(4)
EC2h
—
(4)
EA2h
—
(4)
E82h
—(4)
EE1h
—(4)
EC1h
—(4)
EA1h
—(4)
E81h
—(4)
EE0h
—(4)
EC0h
—(4)
EA0h
—(4)
E80h
—(4)
Note 1:
2:
3:
4:
Shaded registers are available in Access Bank low area while the rest are available in Bank 15.
CANSTAT register is repeated in these locations to simplify application firmware. Unique names are given for
each instance of the controller register due to the Microchip header file requirement.
These registers are not CAN registers.
Unimplemented registers are read as ‘0’.
DS30491D-page 324
2003-2013 Microchip Technology Inc.
18F8680.book Page 325 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 23-1:
Address(1)
CAN CONTROLLER REGISTER MAP (CONTINUED)
Name
Address
Name
Address
Name
Address
Name
E7Fh CANCON_RO4(2)
E5Fh CANCON_RO6(2)
E3Fh CANCON_RO8(2)
E1Fh
—(4)
E7Eh CANSTAT_RO4(2)
E5Eh CANSTAT_RO6(2)
E3Eh CANSTAT_RO8(2)
E1Eh
—(4)
E7Dh
B5D7
E5Dh
B3D7
E3Dh
B1D7
E1Dh
—(4)
E7Ch
B5D6
E5Ch
B3D6
E3Ch
B1D6
E1Ch
—(4)
E7Bh
B5D5
E5Bh
B3D5
E3Bh
B1D5
E1Bh
—(4)
E7Ah
B5D4
E5Ah
B3D4
E3Ah
B1D4
E1Ah
—(4)
E79h
B5D3
E59h
B3D3
E39h
B1D3
E19h
—(4)
E78h
B5D2
E58h
B3D2
E38h
B1D2
E18h
—(4)
E77h
B5D1
E57h
B3D1
E37h
B1D1
E17h
—(4)
E76h
B5D0
E56h
B3D0
E36h
B1D0
E16h
—(4)
E75h
B5DLC
E55h
B3DLC
E35h
B1DLC
E15h
—(4)
E74h
B5EIDL
E54h
B3EIDL
E34h
B1EIDL
E14h
—(4)
E73h
B5EIDH
E53h
B3EIDH
E33h
B1EIDH
E13h
—(4)
E72h
B5SIDL
E52h
B3SIDL
E32h
B1SIDL
E12h
—(4)
E71h
B5SIDH
E51h
B3SIDH
E31h
B1SIDH
E11h
—(4)
E70h
B5CON
E50h
B3CON
E30h
B1CON
E10h
—(4)
E6Fh
CANCON_RO5
E4Fh
CANCON_RO7
E2Fh
CANCON_RO9
E0Fh
—(4)
E6Eh
CANSTAT_RO5
E4Eh
CANSTAT_RO7
E2Eh
CANSTAT_RO9
E0Eh
—(4)
E6Dh
B4D7
E4Dh
B2D7
E2Dh
B0D7
E0Dh
—(4)
E6Ch
B4D6
E4Ch
B2D6
E2Ch
B0D6
E0Ch
—(4)
E6Bh
B4D5
E4Bh
B2D5
E2Bh
B0D5
E0Bh
—(4)
E6Ah
B4D4
E4Ah
B2D4
E2Ah
B0D4
E0Ah
—(4)
E69h
B4D3
E49h
B2D3
E29h
B0D3
E09h
—(4)
E68h
B4D2
E48h
B2D2
E28h
B0D2
E08h
—(4)
E67h
B4D1
E47h
B2D1
E27h
B0D1
E07h
—(4)
E66h
B4D0
E46h
B2D0
E26h
B0D0
E06h
—(4)
E65h
B4DLC
E45h
B2DLC
E25h
B0DLC
E05h
—(4)
E64h
B4EIDL
E44h
B2EIDL
E24h
B0EIDL
E04h
—(4)
E63h
B4EIDH
E43h
B2EIDH
E23h
B0EIDH
E03h
—(4)
E62h
B4SIDL
E42h
B2SIDL
E22h
B0SIDL
E02h
—(4)
E61h
B4SIDH
E41h
B2SIDH
E21h
B0SIDH
E01h
—(4)
E60h
B4CON
E40h
B2CON
E20h
B0CON
E00h
—(4)
Note 1:
2:
3:
4:
Shaded registers are available in Access Bank low area while the rest are available in Bank 15.
CANSTAT register is repeated in these locations to simplify application firmware. Unique names are given for
each instance of the controller register due to the Microchip header file requirement.
These registers are not CAN registers.
Unimplemented registers are read as ‘0’.
2003-2013 Microchip Technology Inc.
DS30491D-page 325
18F8680.book Page 326 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 23-1:
CAN CONTROLLER REGISTER MAP (CONTINUED)
Address(1)
Name
Address
Name
Address
Name
Address
Name
DFFh
—(4)
DDFh
—(4)
DBFh
—(4)
D9Fh
—(4)
DFEh
—(4)
DDEh
—(4)
DBEh
—(4)
D9Eh
—(4)
DFDh
—(4)
DDDh
—(4)
DBDh
—(4)
D9Dh
—(4)
DDCh
—(4)
DBCh
—(4)
D9Ch
—(4)
DDBh
(4)
DBBh
—
(4)
D9Bh
—(4)
(4)
DFCh
TXBIE
DFBh
—
(4)
—
DFAh
BIE0
DDAh
—
DBAh
—
D9Ah
—(4)
DF9h
—(4)
DD9h
—(4)
DB9h
—(4)
D99h
—(4)
DF8h
BSEL0
DD8h
SDFLC
DB8h
—(4)
D98h
—(4)
DF7h
—(4)
DD7h
—(4)
DB7h
—(4)
D97h
—(4)
DF6h
—(4)
DD6h
—(4)
DB6h
—(4)
D96h
—(4)
DF5h
—
(4)
DB5h
—
(4)
D95h
—(4)
—
(4)
(4)
D94h
—(4)
DF4h
DD5h
(4)
RXFCON1
DD4h
RXFCON0
DB4h
—
DF3h
MSEL3
DD3h
—(4)
DB3h
—(4)
D93h
RXF15EIDL
DF2h
MSEL2
DD2h
—(4)
DB2h
—(4)
D92h
RXF15EIDH
DF1h
MSEL1
DD1h
—(4)
DB1h
—(4)
D91h
RXF15SIDL
DF0h
MSEL0
DD0h
—(4)
DB0h
—(4)
D90h
RXF15SIDH
DEFh
—(4)
DCFh
—(4)
DAFh
—(4)
D8Fh
—(4)
DEEh
—
(4)
DCEh
—
(4)
DAEh
—
(4)
D8Eh
—(4)
DEDh
—(4)
DCDh
—(4)
DADh
—(4)
D8Dh
—(4)
DECh
—
(4)
DCCh
—
(4)
DACh
—
(4)
D8Ch
—(4)
DEBh
—
(4)
DCBh
—
(4)
DABh
—
(4)
D8Bh
RXF14EIDL
DEAh
—(4)
DCAh
—(4)
DAAh
—(4)
D8Ah
RXF14EIDH
DE9h
—(4)
DC9h
—(4)
DA9h
—(4)
D89h
RXF14SIDL
DE8h
—(4)
DC8h
—(4)
DA8h
—(4)
D88h
RXF14SIDH
DE7h
RXFBCON7
DC7h
—(4)
DA7h
—(4)
D87h
RXF13EIDL
(4)
DA6h
—(4)
D86h
RXF13EIDH
DE6h
RXFBCON6
DC6h
—
DE5h
RXFBCON5
DC5h
—(4)
DA5h
—(4)
D85h
RXF13SIDL
DA4h
—(4)
D84h
RXF13SIDH
DE4h
RXFBCON4
DC4h
—(4)
DE3h
RXFBCON3
DC3h
—(4)
DA3h
—(4)
D83h
RXF12EIDL
(4)
DA2h
—(4)
D82h
RXF12EIDH
DE2h
RXFBCON2
DC2h
—
DE1h
RXFBCON1
DC1h
—(4)
DA1h
—(4)
D81h
RXF12SIDL
DE0h
RXFBCON0
DC0h
—(4)
DA0h
—(4)
D80h
RXF12SIDH
Note 1:
2:
3:
4:
Shaded registers are available in Access Bank low area while the rest are available in Bank 15.
CANSTAT register is repeated in these locations to simplify application firmware. Unique names are given for
each instance of the controller register due to the Microchip header file requirement.
These registers are not CAN registers.
Unimplemented registers are read as ‘0’.
DS30491D-page 326
2003-2013 Microchip Technology Inc.
18F8680.book Page 327 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TABLE 23-1:
Address(1)
D7Fh
CAN CONTROLLER REGISTER MAP (CONTINUED)
Name
—(4)
D7Eh
—(4)
D7Dh
—(4)
D7Ch
—(4)
D7Bh
RXF11EIDL
D7Ah
RXF11EIDH
D79h
RXF11SIDL
D78h
RXF11SIDH
D77h
RXF10EIDL
D76h
RXF10EIDH
D75h
RXF10SIDL
D74h
RXF10SIDH
D73h
RXF9EIDL
D72h
RXF9EIDH
D71h
RXF9SIDL
D70h
RXF9SIDH
D6Fh
—(4)
D6Eh
—(4)
D6Dh
—(4)
D6Ch
—(4)
D6Bh
RXF8EIDL
D6Ah
RXF8EIDH
D69h
RXF8SIDL
D68h
RXF8SIDH
D67h
RXF7EIDL
D66h
RXF7EIDH
D65h
RXF7SIDL
D64h
RXF7SIDH
D63h
RXF6EIDL
D62h
RXF6EIDH
D61h
RXF6SIDL
D60h
RXF6SIDH
Note 1:
2:
3:
4:
Shaded registers are available in Access Bank low area while the rest are available in Bank 15.
CANSTAT register is repeated in these locations to simplify application firmware. Unique names are given
for each instance of the controller register due to the Microchip header file requirement.
These registers are not CAN registers.
Unimplemented registers are read as ‘0’.
2003-2013 Microchip Technology Inc.
DS30491D-page 327
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PIC18F6585/8585/6680/8680
23.3
CAN Modes of Operation
The PIC18F6585/8585/6680/8680 has six main modes
of operation:
•
•
•
•
•
•
Configuration mode
Disable mode
Normal Operation mode
Listen Only mode
Loopback mode
Error Recognition mode
All modes, except Error Recognition, are requested by
setting the REQOP bits (CANCON); Error Recognition is requested through the RXM bits of the Receive
Buffer register(s). Entry into a mode is Acknowledged
by monitoring the OPMODE bits.
When changing modes, the mode will not actually
change until all pending message transmissions are
complete. Because of this, the user must verify that the
device has actually changed into the requested mode
before further operations are executed.
23.3.1
CONFIGURATION MODE
The CAN module must be initialized before the
activation. This is only possible if the module is in the
Configuration mode. The Configuration mode is
requested by setting the REQOP2 bit. Only when the
status bit, OPMODE2, has a high level can the initialization be performed. Once in Configuration mode,
registers such as baud rate control, acceptance mask/
filter and ECAN mode selection can be modified. A new
ECAN mode selection does not take into effect until
Configuration mode is exited. The module is activated
by setting the REQOP control bits to zero.
The module will protect the user from accidentally
violating the CAN protocol through programming
errors. All registers which control the configuration of
the module can not be modified while the module is
online. The CAN module will not be allowed to enter the
Configuration mode while a transmission or reception
is taking place. The CAN module will also not be
allowed, if the CANRX pin is low (i.e., the CAN bus is
busy). The CAN module waits for 11 recessive bits on
the CAN bus (bus Idle condition) before switching to
Configuration mode. The Configuration mode serves
as a lock to protect the following registers:
•
•
•
•
•
•
•
Configuration registers
Functional Mode Selection registers
Bit Timing registers
Identifier Acceptance Filter registers
Identifier Acceptance Mask registers
Filter and Mask Control registers
Mask Selection registers
DS30491D-page 328
In the Configuration mode, the module will not transmit
or receive. The error counters are cleared and the interrupt flags remain unchanged. The programmer will
have access to configuration registers that are access
restricted in other modes.
23.3.2
DISABLE MODE
In Disable mode, the module will not transmit or
receive. The module has the ability to set the WAKIF bit
due to bus activity; however, any pending interrupts will
remain and the error counters will retain their value.
If REQOP is set to ‘001’, the module will enter the
Module Disable mode. This mode is similar to disabling
other peripheral modules by turning off the module
enables. This causes the module internal clock to stop
unless the module is active (i.e., receiving or transmitting a message). If the module is active, the module will
wait for 11 recessive bits on the CAN bus, detect that
condition as an Idle bus, then accept the module
disable command. OPMODE = 001 indicates
whether the module successfully went into Module
Disable mode.
The WAKIE interrupt is the only module interrupt that is
still active in the Module Disable mode. If wake-up from
CAN bus activity is required, the CAN module must be
put into Disable mode before putting the core to Sleep.
If the WAKDIS is cleared and WAKIE is set, the processor will receive an interrupt whenever the module
detects recessive to dominant transition. On wake-up,
the module will automatically be set to the previous
mode of operation. For example, if the module was
switched from Normal to Disable mode on bus activity
wake-up, the module will automatically enter into
Normal mode and the first message that caused the
module to wake-up is lost. The module will not generate any error frame. Firmware logic must detect this
condition and make sure that retransmission is
requested. If the processor receives a wake-up interrupt while it is sleeping, more than one message may
get lost. The actual number of messages lost would
depend on the processor oscillator start-up time and
incoming message bit rate.
The I/O pins will revert to normal I/O function when the
module is in the Module Disable mode.
Note:
CAN module must be put in Disable or
Configuration mode prior to putting the
processor to sleep. Failure to do that may
put the CAN module in indeterminate
state.
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
23.3.3
NORMAL MODE
23.3.6
ERROR RECOGNITION MODE
This is the standard operating mode of the
PIC18F6585/8585/6680/8680 devices. In this mode,
the device actively monitors all bus messages and generates Acknowledge bits, error frames, etc. This is also
the only mode in which the PIC18F6585/8585/6680/
8680 devices will transmit messages over the CAN
bus.
The module can be set to ignore all errors and receive
any message. In functional Mode 0, the Error Recognition mode is activated by setting the RXM bits in
the RXBnCON registers to ‘11’. In this mode, the data
which is in the message assembly buffer until the error
time, is copied in the receive buffer and can be read via
the CPU interface.
23.3.4
23.4
LISTEN ONLY MODE
Listen Only mode provides a means for the
PIC18F6585/8585/6680/8680 devices to receive all
messages, including messages with errors. This mode
can be used for bus monitor applications or for
detecting the baud rate in ‘hot plugging’ situations. For
auto-baud detection, it is necessary that there are at
least two other nodes which are communicating with
each other. The baud rate can be detected empirically
by testing different values until valid messages are
received. The Listen Only mode is a silent mode,
meaning no messages will be transmitted while in this
state, including error flags or Acknowledge signals. The
filters and masks can be used to allow only particular
messages to be loaded into the receive registers, or the
filter masks can be set to all zeros to allow a message
with any identifier to pass. The error counters are reset
and deactivated in this state. The Listen Only mode is
activated by setting the mode request bits in the
CANCON register.
23.3.5
LOOPBACK MODE
This mode will allow internal transmission of messages
from the transmit buffers to the receive buffers without
actually transmitting messages on the CAN bus. This
mode can be used in system development and testing.
In this mode, the ACK bit is ignored and the device will
allow incoming messages from itself, just as if they
were coming from another node. The Loopback mode
is a silent mode, meaning no messages will be transmitted while in this state, including error flags or
Acknowledge signals. The CANTX pin will revert to port
I/O while the device is in this mode. The filters and
masks can be used to allow only particular messages
to be loaded into the receive registers. The masks can
be set to all zeros to provide a mode that accepts all
messages. The Loopback mode is activated by setting
the mode request bits in the CANCON register.
2003-2013 Microchip Technology Inc.
CAN Module Functional Modes
In addition to CAN modes of operation, the ECAN
module offers a total of three functional modes. Each of
these modes are identified as Mode 0, Mode 1 and
Mode 2.
23.4.1
MODE 0 – LEGACY MODE
Mode 0 is designed to be fully compatible with CAN
modules used in PIC18CXX8 and PIC18FXX8 devices.
This is the default mode of operation on all Reset
conditions. As a result, module code written for the
PIC18XX8 CAN module may be used on the ECAN
module without any code changes.
The following is the list of resources available in Mode 0:
• Three transmit buffers: TXB0, TXB1 and TXB2
• Two receive buffers: RXB0 and RXB1
• Two acceptance masks, one for each receive
buffer: RXM0, RXM1
• Six acceptance filters, 2 for RXB0 and 4 for RXB1:
RXF0, RXF1, RXF2, RXF3, RXF4, RXF5
23.4.2
MODE 1 – ENHANCED LEGACY
MODE
Mode 1 is similar to Mode 0, with the exception that
more resources are available in Mode 1. There are
16 acceptance filters and two Acceptance Mask registers. Acceptance Filter 15 can be used as either an
acceptance filter or an Acceptance Mask register. In
addition to three transmit and two receive buffers, there
are six more message buffers. One or more of these
additional buffers can be programmed as transmit or
receive buffers. These additional buffers can also be
programmed to automatically handle RTR messages.
Fourteen of 16 Acceptance Filter registers can be
dynamically associated to any receive buffer and
Acceptance Mask register. This capability can be used
to associate more than one filter to any one buffer.
DS30491D-page 329
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PIC18F6585/8585/6680/8680
When a receive buffer is programmed to use standard
identifier messages, part of the full Acceptance Filter
register can be used as data byte filter. The length of
data byte filter is programmable from 0 to 18 bits. This
functionality simplifies implementation of high-level
protocols, such as DeviceNet.
The following is the list of resources available in Mode 1:
•
•
•
•
•
Three transmit buffers: TXB0, TXB1 and TXB2
Two receive buffers: RXB0 and RXB1
Six buffers programmable as TX or RX: B0-B5
Automatic RTR handling on B0-B5
Sixteen dynamically assigned acceptance filters:
RXF0-RXF15
• Two dedicated Acceptance Mask registers;
RXF15 programmable as third mask:
RXM0-RXM1, RXF15
• Programmable data filter on standard identifier
messages: SDFLC
23.4.3
MODE 2 – ENHANCED FIFO MODE
In Mode 2, two or more receive buffers are used to form
the receive FIFO (First In First Out) buffer. There is no
one-to-one relation between the receive buffer and
Acceptance Filter registers. Any filter that is enabled
and linked to any FIFO receive buffer can generate
acceptance and cause FIFO to be updated.
FIFO length is user programmable, from 2-8 buffers
deep. FIFO length is determined by the very first
programmable buffer that is configured as a transmit
buffer. For example, if Buffer 2 (B2) is programmed as
a transmit buffer, FIFO consists of RXB0, RXB1, B0
and B1 – creating a FIFO length of 4. If all programmable buffers are configured as receive buffers, FIFO will
have the maximum length of 8.
The following is the list of resources available in Mode 2:
23.5
23.5.1
CAN Message Buffers
DEDICATED TRANSMIT BUFFERS
The PIC18F6585/8585/6680/8680 devices implement
three dedicated transmit buffers – TXB0, TXB1 and
TXB2. Each of these buffers occupies 14 bytes of
SRAM and are mapped into the SFR memory map.
These are the only transmit buffers available in
Mode 0. Mode 1 and 2 may access these and other
additional buffers.
Each transmit buffer contains one Control register
(TXBnCON), four Identifier registers (TXBnSIDL,
TXBnSIDH, TXBnEIDL, TXBnEIDH), one Data Length
Count register (TXBnDLC) and eight Data Byte
registers (TXBnDm).
23.5.2
DEDICATED RECEIVE BUFFERS
The PIC18F6585/8585/6680/8680 devices implement
two dedicated receive buffers – RXB0 and RXB1. Each
of these buffers occupies 14 bytes of SRAM and are
mapped into SFR memory map. These are the only
receive buffers available in Mode 0. Mode 1 and 2 may
access these and other additional buffers.
Each receive buffer contains one Control register
(RXBnCON), four Identifier registers (RXBnSIDL,
RXBnSIDH, RXBnEIDL, RXBnEIDH), one Data Length
Count register (RXBnDLC) and eight Data Byte
registers (RXBnDm).
There is also a separate Message Assembly Buffer
(MAB) which acts as an additional receive buffer. MAB
is always committed to receiving the next message
from the bus and is not directly accessible to user firmware. The MAB assembles all incoming messages one
by one. A message is transferred to appropriate
receive buffers only if the corresponding acceptance
filter criteria is met.
• Three transmit buffers: TXB0, TXB1 and TXB2
• Two receive buffers: RXB0 and RXB1
• Six buffers programmable as TX or RX; receive
buffers form FIFO: B0-B5
• Automatic RTR handling on B0-B5
• Sixteen acceptance filters: RXF0-RXF15
• Two dedicated Acceptance Mask registers;
RXF15 programmable as third mask:
RXM0-RXM1, RXF15
• Programmable data filter on standard identifier
messages: SDFLC, useful for DeviceNet protocol
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PIC18F6585/8585/6680/8680
23.5.3
PROGRAMMABLE TRANSMIT/
RECEIVE BUFFERS
The ECAN module implements six new buffers: B0-B5.
These buffers are individually programmable as either
transmit or receive buffers. These buffers are available
only in Mode 1 and 2. As with dedicated transmit and
receive buffers, each of these programmable buffers
occupies 14 bytes of SRAM and are mapped into SFR
memory map.
Each buffer contains one Control register (BnCON),
four Identifier registers (BnSIDL, BnSIDH, BnEIDL,
BnEIDH), one Data Length Count register (BnDLC)
and eight Data Byte registers (BnDm). Each of these
registers contains two sets of control bits. Depending
on whether the buffer is configured as transmit or
receive, one would use the corresponding control bit
set. By default, all buffers are configured as receive
buffers. Each buffer can be individually configured as
transmit or receive buffers by setting the corresponding
TXENn bit in the BSEL0 register.
When configured as transmit buffers, user firmware
may access transmit buffers in any order similar to
accessing dedicated transmit buffers. In receive configuration, with Mode 1 enabled, user firmware may also
access receive buffers in any order required. But in
Mode 2, all receive buffers are combined to form a single FIFO. Actual FIFO length is programmable by user
firmware. Access to FIFO must be done through the
FIFO pointer bits (FP) in the CANCON register. It
must be noted that there is no hardware protection
against out of order FIFO reads.
23.5.4
PROGRAMMABLE AUTO-RTR
BUFFERS
In Mode 1 and 2, any of six programmable transmit/
receive buffers may be programmed to automatically
respond to predefined RTR messages without user
firmware intervention. Automatic RTR handling is
enabled by setting the TXnEN bit in the BSEL0 register
and the RTREN bit in the BnCON register. After this
setup, when an RTR request is received, the TXREQ
bit is automatically set and current buffer content is
automatically queued for transmission as a RTR
response. As with all transmit buffers, once the TXREQ
bit is set, buffer registers become read-only and any
writes to them will be ignored.
2003-2013 Microchip Technology Inc.
The following outlines the steps
automatically handle RTR messages:
1.
2.
3.
4.
required
to
Set buffer to Transmit mode by setting TXnEN
bit to ‘1’ in BSEL0 register.
At least one acceptance filter must be associated with this buffer and preloaded with
expected RTR identifier.
Bit RTREN in BnCON register must be set to ‘1’.
Buffer must be preloaded with the data to be
sent as a RTR response.
Normally, user firmware will keep Buffer Data registers
up to date. If firmware attempts to update buffer while
an automatic RTR response is in process of
transmission, all writes to buffers are ignored.
23.6
23.6.1
CAN Message Transmission
INITIATING TRANSMISSION
For the MCU to have write access to the message
buffer, the TXREQ bit must be clear, indicating that the
message buffer is clear of any pending message to be
transmitted. At a minimum, the SIDH, SIDL, and DLC
registers must be loaded. If data bytes are present in
the message, the data registers must also be loaded. If
the message is to use extended identifiers, the
EIDH:EIDL registers must also be loaded and the
EXIDE bit set.
To initiate message transmission, the TXREQ bit must
be set for each buffer to be transmitted. When TXREQ
is set, the TXABT, TXLARB and TXERR bits will be
cleared. To successfully complete the transmission,
there must be at least one node with matching baud
rate on the network.
Setting the TXREQ bit does not initiate a message
transmission, it merely flags a message buffer as ready
for transmission. Transmission will start when the
device detects that the bus is available. The device will
then begin transmission of the highest priority message
that is ready.
When the transmission has completed successfully, the
TXREQ bit will be cleared, the TXBnIF bit will be set, and
an interrupt will be generated if the TXBnIE bit is set.
If the message transmission fails, the TXREQ will
remain set, indicating that the message is still pending
for transmission and one of the following condition flags
will be set. If the message started to transmit but
encountered an error condition, the TXERR and the
IRXIF bits will be set and an interrupt will be generated.
If the message lost arbitration, the TXLARB bit will be
set.
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ABORTING TRANSMISSION
Once an abort is requested by setting ABAT or TXABT
bits, it cannot be cleared to cancel the abort request.
Only CAN module hardware or a POR condition can
clear it.
The MCU can request to abort a message by clearing
the TXREQ bit associated with the corresponding message buffer (TXBnCON or BnCON). Setting the
ABAT bit (CANCON) will request an abort of all
pending messages. If the message has not yet started
transmission or if the message started but is interrupted by loss of arbitration or an error, the abort will be
processed. The abort is indicated when the module
sets the TXABT bit for the corresponding buffer
(TXBnCON or BnCON). If the message has
started to transmit, it will attempt to transmit the current
message fully. If the current message is transmitted
fully and is not lost to arbitration or an error, the TXABT
bit will not be set because the message was transmitted successfully. Likewise, if a message is being
transmitted during an abort request and the message is
lost to arbitration or an error, the message will not be
retransmitted and the TXABT bit will be set, indicating
that the message was successfully aborted.
Message
Queue
Control
DS30491D-page 332
MESSAGE
TXB2IF
TXERR
TXLARB
TXABT
TXREQ
TXB3-TXB8
MESSAGE
TXB2IF
TXERR
TXLARB
TXREQ
TXB2
MESSAGE
TXB1IF
TXLARB
TXABT
TXREQ
TXB1
MESSAGE
TXB0IF
TXERR
TXLARB
TXABT
TXB0
TXREQ
TRANSMIT PRIORITY
Transmit priority is a prioritization within the
PIC18F6585/8585/6680/8680 devices of the pending
transmittable messages. This is independent from and
not related to any prioritization implicit in the message
arbitration scheme built into the CAN protocol. Prior to
sending the SOF, the priority of all buffers that are
queued for transmission is compared. The transmit
buffer with the highest priority will be sent first. If more
than one buffer has the same priority setting, the message is transmitted in the order of TXB2, TXB1, TXB0,
B5, B4, B3, B2, B1, B0. There are four levels of transmit
priority. If TXP bits for a particular message buffer are
set to ‘11’, that buffer has the highest possible priority.
If TXP bits for a particular message buffer are ‘00’, that
buffer has the lowest possible priority.
TRANSMIT BUFFERS
TXERR
FIGURE 23-2:
23.6.3
TXABT
23.6.2
Transmit Byte Sequencer
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23.7
23.7.1
Message Reception
RECEIVING A MESSAGE
Of all receive buffers, the MAB is always committed to
receiving the next message from the bus. The MCU
can access one buffer while the other buffer is available
for message reception, or holding a previously received
message.
Note:
The entire contents of the MAB are moved
into the receive buffer once a message is
accepted. This means that regardless of
the type of identifier (standard or
extended) and the number of data bytes
received, the entire receive buffer is overwritten with the MAB contents. Therefore,
the contents of all registers in the buffer
must be assumed to have been modified
when any message is received.
When a message is moved into either of the receive
buffers, the associated RXFUL bit is set. This bit must
be cleared by the MCU when it has completed processing the message in the buffer in order to allow a new
message to be received into the buffer. This bit
provides a positive lockout to ensure that the firmware
has finished with the message before the module
attempts to load a new message into the receive buffer.
If the receive interrupt is enabled, an interrupt will be
generated to indicate that a valid message has been
received.
Once a message is loaded into any matching buffer,
user firmware may determine exactly what filter caused
this reception by checking the filter hit bits in the
RXBnCON or BnCON registers. In Mode 0, FILHIT
of RXBnCON serve as filter hit bits. In Mode 1 and 2,
FILHIT of BnCON serve as filter hit bits. The same
registers also indicate whether the current message is
RTR frame or not. A received message is considered a
standard identifier message if the EXID bit in RXBnSIDL
or the BnSIDL register is cleared. Conversely, a set
EXID bit indicates an extended identifier message. If the
received message is a standard identifier message, user
firmware needs to read the SIDL and SIDH registers. In
the case of an extended identifier message, firmware
should read the SIDL, SIDH, EIDL and EIDH registers. If
the RXBnDLC or BnDLC register contain non-zero data
count, user firmware should also read the corresponding
number of data bytes by accessing the RXBnDm or
BnDm registers. When a received message is RTR and
if the current buffer is not configured for automatic RTR
handling, user firmware must take appropriate action
and respond manually.
2003-2013 Microchip Technology Inc.
Each receive buffer contains RXM bits to set special
Receive modes. In Mode 0, RXM bits in
RXBnCON define a total of four Receive modes. In
Mode 1 and 2, RXM1 bit in combination with the EXID
mask and filter bit define the same four Receive
modes. Normally, these bits are set to ‘00’ to enable
reception of all valid messages as determined by the
appropriate acceptance filters. In this case, the determination of whether or not to receive standard or
extended messages is determined by the EXIDE bit in
the Acceptance Filter register. In Mode 0, if the RXM
bits are set to ‘01’ or ‘10’, the receiver will accept only
messages with standard or extended identifiers,
respectively. If an acceptance filter has the EXIDE bit
set such that it does not correspond with the RXM
mode, that acceptance filter is rendered useless. In
Mode 1 and 2, setting EXID in the SIDL Mask register
will ensure that only standard or extended identifiers
are received. These two modes of RXM bits can be
used in systems where it is known that only standard or
extended messages will be on the bus. If the RXM bits
are set to ‘11’ (RXM1 = 1 in Mode 1 and 2), the buffer
will receive all messages regardless of the values of
the acceptance filters. Also, if a message has an error
before the end of frame, that portion of the message
assembled in the MAB before the error frame, will be
loaded into the buffer. This mode may serve as a valuable debugging tool for a given CAN network. It should
not be used in an actual system environment as the
actual system will always have some bus errors and all
nodes on the bus are expected to ignore them.
In Mode 1 and 2, when a programmable buffer is
configured as a transmit buffer and one or more acceptance filters are associated with it, all incoming messages matching this acceptance filter criteria will be
discarded. To avoid this scenario, user firmware must
make sure that there are no acceptance filters associated with a buffer configured as a transmit buffer.
23.7.2
RECEIVE PRIORITY
When in Mode 0, RXB0 is the higher priority buffer and
has two message acceptance filters associated with it.
RXB1 is the lower priority buffer and has four acceptance
filters associated with it. The lower number of acceptance
filters makes the match on RXB0 more restrictive and
implies a higher priority for that buffer. Additionally, the
RXB0CON register can be configured such that if RXB0
contains a valid message and another valid message is
received, an overflow error will not occur and the new
message will be moved into RXB1 regardless of the
acceptance criteria of RXB1. There are also two
programmable acceptance filter masks available, one for
each receive buffer (see Section 4.5).
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In Mode 1 and 2, there are a total of 16 acceptance filters available and each can be dynamically assigned to
any of the receive buffers. A buffer with a lower number
has higher priority. Given this, if an incoming message
matches with two or more receive buffer acceptance
criteria, the buffer with the lower number will be loaded
with that message.
23.7.4
23.7.3
To use the time-stamp capability, the CANCAP bit
(CIOCAN) must be set. This replaces the capture
input for CCP1 with the signal generated from the CAN
module. In addition, CCP1CON must be set to
‘0011’ to enable the CCP special event trigger for CAN
events.
ENHANCED FIFO MODE
When configured for Mode 2, two of the dedicated
receive buffers, in combination with one or more programmable transmit/receive buffers, are used to create
a maximum of 8 buffers deep FIFO (First In First Out)
buffer. In this mode, there is no direct correlation
between filters and receive buffer registers. Any filter
that has been enabled can generate an acceptance.
When a message has been accepted, it is stored in the
next available receive buffer register and an internal
write pointer is incremented. The FIFO can be a maximum of 8 buffers deep. The entire FIFO must consist of
contiguous receive buffers. The FIFO head begins at
RXB0 buffer and its tail spans toward B5. The maximum length of the FIFO is limited by the presence or
absence of the first transmit buffer starting from B0. If a
buffer is configured as a transmit buffer, the FIFO
length is reduced accordingly. For instance, if B3 is
configured as transmit buffer, the actual FIFO will consist of RXB0, RXB1, B0, B1 and B2, a total of 5 buffers.
If B0 is configured as a transmit buffer, the FIFO length
will be 2. If none of the programmable buffers are configured as a transmit buffer, the FIFO will be 8 buffers
deep. A system that requires more transmit buffers
should try to locate transmit buffers at the very end of
B0-B5 buffers to maximize available FIFO length.
When a message is received in FIFO mode, the Interrupt Flag Code bits (EICODE) in the CANSTAT
register will have a value of ‘10000’, indicating the
FIFO has received a message. FIFO pointer bits
FP in the CANCON register point to the buffer
that contains data not yet read. The FIFO pointer bits,
in this sense, serve as the FIFO read pointer. The user
should use FP bits and read corresponding buffer data.
When receive data is no longer needed, the RXFUL bit
in the current buffer must be cleared, causing FP
to be updated by the module.
To determine whether FIFO is empty or not, the user
may use FP bits to access RXFUL bit in the current buffer. If RXFUL is cleared, the FIFO is considered
to be empty. If it is set, the FIFO may contain one or
more messages. In Mode 2, the module also provides
a bit called FIFO High Water Mark (FIFOWM) in the
ECANCON register. This bit can be used to cause an
interrupt whenever the FIFO contains only one or four
empty buffers. The FIFO high water mark interrupt can
serve as an early warning to a full FIFO condition.
DS30491D-page 334
TIME-STAMPING
The CAN module can be programmed to generate a
time-stamp for every message that is received. When
enabled, the module generates a capture signal for
CCP1, which in turn captures the value of either Timer1
or Timer3. This value can be used as the message
time-stamp.
23.8
Message Acceptance Filters
and Masks
The message acceptance filters and masks are used to
determine if a message in the message assembly
buffer should be loaded into any of the receive buffers.
Once a valid message has been received into the MAB,
the identifier fields of the message are compared to the
filter values. If there is a match, that message will be
loaded into the appropriate receive buffer. The filter
masks are used to determine which bits in the identifier
are examined with the filters. A truth table is shown
below in Table 23-2 that indicates how each bit in the
identifier is compared to the masks and filters to determine if a message should be loaded into a receive
buffer. The mask essentially determines which bits to
apply the acceptance filters to. If any mask bit is set to
a zero, then that bit will automatically be accepted
regardless of the filter bit.
TABLE 23-2:
FILTER/MASK TRUTH TABLE
Mask
bit n
Filter
bit n
Message
Identifier
bit n001
Accept or
Reject
bit n
0
x
x
Accept
1
0
0
Accept
1
0
1
Reject
1
1
0
Reject
1
1
1
Accept
Legend: x = don’t care
In Mode 0, acceptance filters RXF0 and RXF1 and filter
mask RXM0 are associated with RXB0. Filters RXF2,
RXF3, RXF4 and RXF5 and mask RXM1 are
associated with RXB1.
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In Mode 1 and 2, there are an additional 10 acceptance
filters, RXF6-RXF15, creating a total of 16 available
filters. RXF15 can be used either as an acceptance
filter or acceptance mask register. Each of these
acceptance filters can be individually enabled or
disabled by setting or clearing RXFENn bit in the
RXFCONn register. Any of these 16 acceptance filters
can be dynamically associated with any of the receive
buffers. Actual association is made by setting appropriate bits in the RXFBCONn register. Each RXFBCONn
register contains a nibble for each filter. This nibble can
be used to associate a specific filter to any of available
receive buffers. User firmware may associate more
than one filter to any one specific receive buffer.
The coding of the RXB0DBEN bit enables these three
bits to be used similarly to the FILHIT bits and to distinguish a hit on filter RXF0 and RXF1, in either RXB0 or
after a rollover into RXB1.
In addition to dynamic filter to buffer association, in
Mode 1 and 2, each filter can also be dynamically associated to available acceptance mask registers. FILn_m
bits in the MSELn register can be used to link a specific
acceptance filter to an acceptance mask register. As
with filter to buffer association, one can also associate
more than one mask to a specific acceptance filter.
In Mode 1 and 2, each buffer control register contains
5 bits of filter hit bits FILHIT. A binary value of ‘0’
indicates a hit from RXF0 and 15 indicates RXF15.
When a filter matches and a message is loaded into the
receive buffer, the filter number that enabled the
message reception is loaded into the FILHIT bit(s). In
Mode 0 for RXB1, the RXB1CON register contains the
FILHIT bits. They are coded as follows:
•
•
•
•
•
•
101
100
011
010
001
000
= Acceptance Filter 5 (RXF5)
= Acceptance Filter 4 (RXF4)
= Acceptance Filter 3 (RXF3)
= Acceptance Filter 2 (RXF2)
= Acceptance Filter 1 (RXF1)
= Acceptance Filter 0 (RXF0)
Note:
•
•
•
•
111
110
001
000
= Acceptance Filter 1 (RXF1)
= Acceptance Filter 0 (RXF0)
= Acceptance Filter 1 (RXF1)
= Acceptance Filter 0
If the RXB0DBEN bit is clear, there are six codes corresponding to the six filters. If the RXB0DBEN bit is set,
there are six codes corresponding to the six filters plus
two additional codes corresponding to RXF0 and RXF1
filters that rollover into RXB1.
If more than one acceptance filter matches, the FILHIT
bits will encode the binary value of the lowest
numbered filter that matched. In other words, if filter
RXF2 and filter RXF4 match, FILHIT will be loaded with
the value for RXF2. This essentially prioritizes the
acceptance filters with a lower number filter having
higher priority. Messages are compared to filters in
ascending order of filter number.
The mask and filter registers can only be modified
when the PIC18F6585/8585/6680/8680 devices are in
Configuration mode.
‘000’ and ‘001’ can only occur if the
RXB0DBEN bit is set in the RXB0CON
register, allowing RXB0 messages to
rollover into RXB1.
FIGURE 23-3:
MESSAGE ACCEPTANCE MASK AND FILTER OPERATION
Acceptance Filter Register
RXFn0
Acceptance Mask Register
RXMn0
RXMn1
RXFn1
RXFnn
RxRqst
RXMnn
Message Assembly Buffer
Identifier
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23.9
Baud Rate Setting
All nodes on a given CAN bus must have the same
nominal bit rate. The CAN protocol uses Non-Returnto-Zero (NRZ) coding which does not encode a clock
within the data stream. Therefore, the receive clock
must be recovered by the receiving nodes and
synchronized to the transmitter’s clock.
As oscillators and transmission time may vary from
node to node, the receiver must have some type of
Phase Lock Loop (PLL) synchronized to data transmission edges to synchronize and maintain the receiver
clock. Since the data is NRZ coded, it is necessary to
include bit stuffing to ensure that an edge occurs at
least every six bit times to maintain the Digital Phase
Lock Loop (DPLL) synchronization.
The bit timing of the PIC18F6585/8585/6680/8680 is
implemented using a DPLL that is configured to synchronize to the incoming data and provides the nominal
timing for the transmitted data. The DPLL breaks each
bit time into multiple segments made up of minimal
periods of time called the Time Quanta (TQ).
Bus timing functions executed within the bit time frame,
such as synchronization to the local oscillator, network
transmission delay compensation, and sample point
positioning, are defined by the programmable bit timing
logic of the DPLL.
All devices on the CAN bus must use the same bit rate.
However, all devices are not required to have the same
master oscillator clock frequency. For the different clock
frequencies of the individual devices, the bit rate has to
be adjusted by appropriately setting the baud rate
prescaler and number of time quanta in each segment.
The Nominal Bit Rate is the number of bits transmitted
per second, assuming an ideal transmitter with an ideal
oscillator, in the absence of resynchronization. The
nominal bit rate is defined to be a maximum of 1 Mb/s.
FIGURE 23-4:
The Nominal Bit Time is defined as:
EQUATION 23-1:
TBIT = 1/Nominal Bit Rate
The Nominal Bit Time can be thought of as being
divided into separate, non-overlapping time segments.
These segments (Figure 23-4) include:
•
•
•
•
Synchronization Segment (Sync_Seg)
Propagation Time Segment (Prop_Seg)
Phase Buffer Segment 1 (Phase_Seg1)
Phase Buffer Segment 2 (Phase_Seg2)
The time segments (and thus the Nominal Bit Time) are
in turn made up of integer units of time called Time
Quanta or TQ (see Figure 23-4). By definition, the Nominal Bit Time is programmable from a minimum of 8 TQ
to a maximum of 25 TQ. Also by definition, the minimum
Nominal Bit Time is 1 s, corresponding to a maximum
1 Mb/s rate. The actual duration is given by the
relationship:
EQUATION 23-2:
Nominal Bit Time = TQ * (Sync_Seg + Prop_Seg +
Phase_Seg1 + Phase_Seg2)
The Time Quantum is a fixed unit derived from the
oscillator period. It is also defined by the programmable
baud rate prescaler with integer values from 1 to 64 in
addition to a fixed divide-by-two for clock generation.
Mathematically, this is:
EQUATION 23-3:
TQ (s) = (2 * (BRP+1))/FOSC (MHz)
or
TQ (s) = (2 * (BRP+1)) * TOSC (s)
where FOSC is the clock frequency, TOSC is the corresponding oscillator period, and BRP is an integer (0
through 63) represented by the binary values of
BRGCON1.
BIT TIME PARTITIONING
Input
Signal
Bit
Time
Intervals
Sync
Segment
Propagation
Segment
Phase
Segment 1
Phase
Segment 2
TQ
Sample Point
Nominal Bit Time
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23.9.1
TIME QUANTA
23.9.2
SYNCHRONIZATION SEGMENT
As already mentioned, the Time Quanta is a fixed unit
derived from the oscillator period and baud rate
prescaler. Its relationship to TBIT and the Nominal Bit
Rate is shown in Example 23-6.
This part of the bit time is used to synchronize the
various CAN nodes on the bus. The edge of the input
signal is expected to occur during the sync segment.
The duration is 1 TQ.
EXAMPLE 23-6:
23.9.3
CALCULATING TQ,
NOMINAL BIT RATE AND
NOMINAL BIT TIME
TQ (s) = (2 * (BRP+1))/FOSC (MHz)
TBIT (s) = TQ (s) * number of TQ per bit interval
Nominal Bit Rate (bits/s) = 1/TBIT
23.9.4
CASE 1:
PROPAGATION SEGMENT
This part of the bit time is used to compensate for physical delay times within the network. These delay times
consist of the signal propagation time on the bus line
and the internal delay time of the nodes. The length of
the Propagation Segment can be programmed from
1 TQ to 8 TQ by setting the PRSEG2:PRSEG0 bits.
PHASE BUFFER SEGMENTS
TBIT = 8 * 0.2 = 1.6 s (1.6 * 10-6s)
The phase buffer segments are used to optimally
locate the sampling point of the received bit within the
nominal bit time. The sampling point occurs between
Phase Segment 1 and Phase Segment 2. These
segments can be lengthened or shortened by the
resynchronization process. The end of Phase Segment
1 determines the sampling point within a bit time.
Phase Segment 1 is programmable from 1 TQ to 8 TQ
in duration. Phase Segment 2 provides delay before
the next transmitted data transition and is also
programmable from 1 TQ to 8 TQ in duration. However,
due to IPT requirements, the actual minimum length of
Phase Segment 2 is 2 TQ, or it may be defined to be
equal to the greater of Phase Segment 1 or the
Information Processing Time (IPT).
Nominal Bit Rate = 1/1.6 * 10-6s = 625,000 bits/s
(625 Kb/s)
23.9.5
For FOSC = 16 MHz, BRP = 00h and
Nominal Bit Time = 8 TQ:
TQ = (2*1)/16 = 0.125 s (125 ns)
TBIT = 8 * 0.125 = 1 s (10-6s)
Nominal Bit Rate = 1/10-6 = 106 bits/s (1 Mb/s)
CASE 2:
For FOSC = 20 MHz, BRP = 01h and
Nominal Bit Time = 8 TQ:
TQ = (2*2)/20 = 0.2 s (200 ns)
CASE 3:
For FOSC = 25 MHz, BRP = 3Fh and
Nominal Bit Time = 25 TQ:
TQ = (2*64)/25 = 5.12 s
TBIT = 25 * 5.12 = 128 s (1.28 * 10-4s)
Nominal Bit Rate = 1/1.28 * 10-4 = 7813 bits/s
(7.8 Kb/s)
The frequencies of the oscillators in the different nodes
must be coordinated in order to provide a system wide
specified nominal bit time. This means that all oscillators must have a TOSC that is an integral divisor of TQ.
It should also be noted that although the number of TQ
is programmable from 4 to 25, the usable minimum is
8 TQ. A bit time of less than 8 TQ in length is not
guaranteed to operate correctly.
2003-2013 Microchip Technology Inc.
SAMPLE POINT
The sample point is the point of time at which the bus
level is read and the value of the received bit is determined. The sampling point occurs at the end of Phase
Segment 1. If the bit timing is slow and contains many
TQ, it is possible to specify multiple sampling of the bus
line at the sample point. The value of the received bit is
determined to be the value of the majority decision of
three values. The three samples are taken at the sample point and twice before, with a time of TQ/2 between
each sample.
23.9.6
INFORMATION PROCESSING TIME
The Information Processing Time (IPT) is the time
segment starting at the sample point that is reserved
for calculation of the subsequent bit level. The CAN
specification defines this time to be less than or equal
to 2 TQ. The PIC18F6585/8585/6680/8680 devices
define this time to be 2 TQ. Thus, Phase Segment 2
must be at least 2 TQ long.
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23.10 Synchronization
To compensate for phase shifts between the oscillator
frequencies of each of the nodes on the bus, each CAN
controller must be able to synchronize to the relevant
signal edge of the incoming signal. When an edge in
the transmitted data is detected, the logic will compare
the location of the edge to the expected time
(Sync_Seg). The circuit will then adjust the values of
Phase Segment 1 and Phase Segment 2 as necessary.
There are two mechanisms used for synchronization.
23.10.1
HARD SYNCHRONIZATION
Hard synchronization is only done when there is a
recessive to dominant edge during a bus Idle condition,
indicating the start of a message. After hard synchronization, the bit time counters are restarted with
Sync_Seg. Hard synchronization forces the edge
which has occurred to lie within the synchronization
segment of the restarted bit time. Due to the rules of
synchronization, if a hard synchronization occurs there
will not be a resynchronization within that bit time.
23.10.2
RESYNCHRONIZATION
As a result of resynchronization, Phase Segment 1
may be lengthened or Phase Segment 2 may be shortened. The amount of lengthening or shortening of the
phase buffer segments has an upper bound given by
the Synchronization Jump Width (SJW). The value of
the SJW will be added to Phase Segment 1 (see
Figure 23-5) or subtracted from Phase Segment 2 (see
Figure 23-6). The SJW is programmable between 1 TQ
and 4 TQ.
Clocking information will only be derived from recessive to dominant transitions. The property that only a
fixed maximum number of successive bits have the
same value, ensures resynchronization to the bit
stream during a frame.
DS30491D-page 338
The phase error of an edge is given by the position of
the edge relative to Sync_Seg, measured in TQ. The
phase error is defined in magnitude of TQ as follows:
• e = 0 if the edge lies within Sync_Seg.
• e > 0 if the edge lies before the sample point.
• e < 0 if the edge lies after the sample point of the
previous bit.
If the magnitude of the phase error is less than, or equal
to the programmed value of the synchronization jump
width, the effect of a resynchronization is the same as
that of a hard synchronization.
If the magnitude of the phase error is larger than the
synchronization jump width, and if the phase error is
positive, then Phase Segment 1 is lengthened by an
amount equal to the synchronization jump width.
If the magnitude of the phase error is larger than the
resynchronization jump width, and if the phase error is
negative, then Phase Segment 2 is shortened by an
amount equal to the synchronization jump width.
23.10.3
SYNCHRONIZATION RULES
• Only one synchronization within one bit time is
allowed.
• An edge will be used for synchronization only if
the value detected at the previous sample point
(previously read bus value) differs from the bus
value immediately after the edge.
• All other recessive to dominant edges fulfilling
rules 1 and 2 will be used for resynchronization,
with the exception that a node transmitting a
dominant bit will not perform a resynchronization
as a result of a recessive to dominant edge with a
positive phase error.
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FIGURE 23-5:
LENGTHENING A BIT PERIOD (ADDING SJW TO PHASE SEGMENT 1)
Input
Signal
Bit
Time
Segments
Sync
Prop
Segment
Phase
Segment 1
Phase
Segment 2
SJW
TQ
Sample Point
Nominal Bit Length
Actual Bit Length
FIGURE 23-6:
Sync
SHORTENING A BIT PERIOD (SUBTRACTING SJW FROM PHASE SEGMENT 2)
Prop
Segment
Phase
Segment 1
TQ
Phase
Segment 2
SJW
Sample Point
Actual Bit Length
Nominal Bit Length
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23.11 Programming Time Segments
23.13.2
Some requirements for programming of the time
segments:
The PRSEG bits set the length of the propagation segment in terms of TQ. The SEG1PH bits set the length of
Phase Segment 1 in TQ. The SAM bit controls how
many times the RXCAN pin is sampled. Setting this bit
to a ‘1’ causes the bus to be sampled three times; twice
at TQ/2 before the sample point and once at the normal
sample point (which is at the end of Phase Segment 1).
The value of the bus is determined to be the value read
during at least two of the samples. If the SAM bit is set
to a ‘0’, then the RXCAN pin is sampled only once at
the sample point. The SEG2PHTS bit controls how the
length of Phase Segment 2 is determined. If this bit is
set to a ‘1’, then the length of Phase Segment 2 is
determined by the SEG2PH bits of BRGCON3. If the
SEG2PHTS bit is set to a ‘0’, then the length of Phase
Segment 2 is the greater of Phase Segment 1 and the
information processing time (which is fixed at 2 TQ for
the PIC18F6585/8585/6680/8680).
• Prop_Seg + Phase_Seg 1 Phase_Seg 2
• Phase_Seg 2 Sync Jump Width.
For example, assume that a 125 kHz CAN baud rate is
desired, using 20 MHz for FOSC. With a TOSC of 50 ns,
a baud rate prescaler value of 04h gives a TQ of 500 ns.
To obtain a Nominal Bit Rate of 125 kHz, the Nominal
Bit Time must be 8 s or 16 TQ.
Using 1 TQ for the Sync_Seg, 2 TQ for the Prop_Seg
and 7 TQ for Phase Segment 1, would place the sample
point at 10 TQ after the transition. This leaves 6 TQ for
Phase Segment 2.
By the rules above, the Sync Jump Width could be the
maximum of 4 TQ. However, normally a large SJW is
only necessary when the clock generation of the
different nodes is inaccurate or unstable, such as using
ceramic resonators. Typically, an SJW of 1 is enough.
23.12 Oscillator Tolerance
As a rule of thumb, the bit timing requirements allow
ceramic resonators to be used in applications with
transmission rates of up to 125 Kbit/sec. For the full bus
speed range of the CAN protocol, a quartz oscillator is
required. A maximum node-to-node oscillator variation
of 1.7% is allowed.
23.13 Bit Timing Configuration
Registers
The Configuration registers (BRGCON1, BRGCON2,
BRGCON3) control the bit timing for the CAN bus
interface. These registers can only be modified when
the PIC18F6585/8585/6680/8680 devices are in
Configuration mode.
23.13.1
BRGCON1
The BRP bits control the baud rate prescaler. The
SJW bits select the synchronization jump width in
terms of multiples of TQ.
DS30491D-page 340
23.13.3
BRGCON2
BRGCON3
The PHSEG2 bits set the length (in TQ) of Phase
Segment 2 if the SEG2PHTS bit is set to a ‘1’. If the
SEG2PHTS bit is set to a ‘0’, then the PHSEG2
bits have no effect.
23.14 Error Detection
The CAN protocol provides sophisticated error
detection mechanisms. The following errors can be
detected.
23.14.1
CRC ERROR
With the Cyclic Redundancy Check (CRC), the transmitter calculates special check bits for the bit
sequence, from the start of a frame until the end of the
data field. This CRC sequence is transmitted in the
CRC field. The receiving node also calculates the CRC
sequence using the same formula and performs a
comparison to the received sequence. If a mismatch is
detected, a CRC error has occurred and an error frame
is generated. The message is repeated.
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23.14.2
ACKNOWLEDGE ERROR
In the Acknowledge field of a message, the transmitter
checks if the Acknowledge slot (which was sent out as
a recessive bit) contains a dominant bit. If not, no other
node has received the frame correctly. An Acknowledge error has occurred; an error frame is generated
and the message will have to be repeated.
23.14.3
FORM ERROR
If a node detects a dominant bit in one of the four
segments, including end of frame, interframe space,
Acknowledge delimiter, or CRC delimiter, then a form
error has occurred and an error frame is generated.
The message is repeated.
23.14.4
BIT ERROR
A bit error occurs if a transmitter sends a dominant bit
and detects a recessive bit, or if it sends a recessive bit
and detects a dominant bit, when monitoring the actual
bus level and comparing it to the just transmitted bit. In
the case where the transmitter sends a recessive bit
and a dominant bit is detected during the arbitration
field and the Acknowledge slot, no bit error is
generated because normal arbitration is occurring.
23.14.5
STUFF BIT ERROR
lf between the start of frame and the CRC delimiter, six
consecutive bits with the same polarity are detected,
the bit stuffing rule has been violated. A stuff bit error
occurs and an error frame is generated. The message
is repeated.
23.14.6
ERROR STATES
Detected errors are made public to all other nodes via
error frames. The transmission of the erroneous message is aborted and the frame is repeated as soon as
possible. Furthermore, each CAN node is in one of the
three error states “error-active”, “error-passive” or “busoff” according to the value of the internal error counters.
The error-active state is the usual state where the bus
2003-2013 Microchip Technology Inc.
node can transmit messages and activate error frames
(made of dominant bits) without any restrictions. In the
error-passive state, messages and passive error
frames (made of recessive bits) may be transmitted.
The bus-off state makes it temporarily impossible for
the station to participate in the bus communication.
During this state, messages can neither be received
nor transmitted.
23.14.7
ERROR MODES AND ERROR
COUNTERS
The PIC18F6585/8585/6680/8680 devices contain two
error counters: the Receive Error Counter
(RXERRCNT), and the Transmit Error Counter
(TXERRCNT). The values of both counters can be read
by the MCU. These counters are incremented or
decremented in accordance with the CAN bus
specification.
The PIC18F6585/8585/6680/8680 devices are erroractive if both error counters are below the error-passive
limit of 128. They are error-passive if at least one of the
error counters equals or exceeds 128. They go to busoff if the transmit error counter equals or exceeds the
bus-off limit of 256. The devices remain in this state
until the bus-off recovery sequence is received. The
bus-off recovery sequence consists of 128 occurrences
of 11 consecutive recessive bits (see Figure 23-7).
Note that the CAN module, after going bus-off, will
recover back to error-active without any intervention by
the MCU if the bus remains Idle for 128 x 11 bit times.
If this is not desired, the error Interrupt Service Routine
should address this. The current Error mode of the
CAN module can be read by the MCU via the
COMSTAT register.
Additionally, there is an error state warning flag bit,
EWARN, which is set if at least one of the error
counters equals or exceeds the error warning limit of
96. EWARN is reset if both error counters are less than
the error warning limit.
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FIGURE 23-7:
ERROR MODES STATE DIAGRAM
Reset
ErrorActive
RXERRCNT < 127 or
TXERRCNT < 127
RXERRCNT > 127 or
TXERRCNT > 127
128 occurrences of
11 consecutive
“recessive” bits
ErrorPassive
TXERRCNT > 255
BusOff
23.15 CAN Interrupts
The transmit related interrupts are:
The module has several sources of interrupts. Each of
these interrupts can be individually enabled or disabled. The PIR3 register contains interrupt flags. The
PIE3 register contains the enables for the 8 main interrupts. A special set of read-only bits in the CANSTAT
register, the ICODE bits, can be used in combination
with a jump table for efficient handling of interrupts.
•
•
•
•
All interrupts have one source with the exception of the
error interrupt and buffer interrupts in Mode 1 and 2. Any
of the error interrupt sources can set the error interrupt
flag. The source of the error interrupt can be determined
by reading the Communication Status register,
COMSTAT. In Mode 1 and 2, there are two interrupt
enable/disable and flag bits – one for all transmit buffers
and the other for all receive buffers.
The interrupts can be broken up into two categories:
receive and transmit interrupts.
The receive related interrupts are:
•
•
•
•
•
Receive Interrupts
Wake-up Interrupt
Receiver Overrun Interrupt
Receiver Warning Interrupt
Receiver Error-Passive Interrupt
DS30491D-page 342
Transmit Interrupts
Transmitter Warning Interrupt
Transmitter Error-Passive Interrupt
Bus-Off Interrupt
23.15.1
INTERRUPT CODE BITS
To simplify the interrupt handling process in user firmware, the ECAN module encodes a special set of bits. In
Mode 0, these bits are ICODE in the CANSTAT
register. In Mode 1 and 2, these bits are EICODE
in the CANSTAT register. Interrupts are internally prioritized such that the higher priority interrupts are assigned
lower values. Once the highest priority interrupt condition has been cleared, the code for the next highest
priority interrupt that is pending (if any) will be reflected
by the ICODE bits. Note that only those interrupt sources
that have their associated interrupt enable bit set will be
reflected in the ICODE bits.
In Mode 2, when a receive message interrupt occurs,
EICODE bits will always consist of ‘10000’. User
firmware may use FIFO pointer bits to actually access
the next available buffer.
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23.15.2
TRANSMIT INTERRUPT
When the transmit interrupt is enabled, an interrupt will
be generated when the associated transmit buffer
becomes empty and is ready to be loaded with a new
message. In Mode 0, there are separate interrupt
enable/disable and flag bits for each of the three
dedicated transmit buffers. The TXBnIF bit will be set to
indicate the source of the interrupt. The interrupt is
cleared by the MCU resetting the TXBnIF bit to a ‘0’. In
Mode 1 and 2, all transmit buffers share one interrupt
enable/disable and flag bits. In Mode 1 and 2, TXBIE in
PIE3 and TXBIF in PIR3 indicate when a transmit buffer
has completed transmission of its message. TXBnIF,
TXBnIE and TXBnIP in PIR3, PIE3 and IPR3, respectively, are not used in Mode 1 and 2. Individual transmit
buffer interrupts can be enabled or disabled by setting or
clearing TXBIE and BnIE register bits. When a shared
interrupt occurs, user firmware must poll the TXREQ bit
of all transmit buffers to detect the source of interrupt.
23.15.3
RECEIVE INTERRUPT
When the receive interrupt is enabled, an interrupt will
be generated when a message has been successfully
received and loaded into the associated receive buffer.
This interrupt is activated immediately after receiving
the End Of Frame (EOF) field.
In Mode 0, the RXBnIF bit is set to indicate the source
of the interrupt. The interrupt is cleared by the MCU
resetting the RXBnIF bit to a ‘0’.
In Mode 1 and 2, all receive buffers share one interrupt.
Individual receive buffer interrupts can be controlled by
the RXBnIE and BIEn registers. In Mode 1, when a
shared receive interrupt occurs, user firmware must
poll the RXFUL bit of each receive buffer to detect the
source of interrupt. In Mode 2, a receive interrupt
indicates that the new message is loaded into FIFO.
FIFO can be read by using FIFO pointer bits, FP.
In Mode 2, the FIFOWMIF bit indicates if the FIFO high
watermark is reached. The FIFO high watermark is
defined by the FIFOWM bit in the ECANCON register.
23.15.5
When the PIC18F6585/8585/6680/8680 devices are in
Sleep mode and the bus activity wake-up interrupt is
enabled, an interrupt will be generated and the WAKIF
bit will be set when activity is detected on the CAN bus.
This interrupt causes the PIC18F6585/8585/6680/
8680 devices to exit Sleep mode. The interrupt is reset
by the MCU, clearing the WAKIF bit.
23.15.6
MESSAGE ERROR INTERRUPT
When an error occurs during transmission or reception
of a message, the message error flag, IRXIF, will be set
and if the IRXIE bit is set, an interrupt will be generated.
This is intended to be used to facilitate baud rate
determination when used in conjunction with Listen
Only mode.
ERROR INTERRUPT
When the error interrupt is enabled, an interrupt is
generated if an overflow condition occurs or if the error
state of the transmitter or receiver has changed. The
error flags in COMSTAT will indicate one of the
following conditions.
23.15.6.1
Receiver Overflow
An overflow condition occurs when the MAB has
assembled a valid received message (the message
meets the criteria of the acceptance filters) and the
receive buffer associated with the filter is not available
for loading of a new message. The associated
COMSTAT.RXnOVFL bit will be set to indicate the
overflow condition. This bit must be cleared by the
MCU.
23.15.6.2
Receiver Warning
The receive error counter has reached the MCU
warning limit of 96.
23.15.6.3
Transmitter Warning
The transmit error counter has reached the MCU
warning limit of 96.
23.15.6.4
Receiver Bus Passive
The receive error counter has exceeded the errorpassive limit of 127 and the device has gone to
error-passive state.
23.15.6.5
23.15.4
BUS ACTIVITY WAKE-UP
INTERRUPT
Transmitter Bus Passive
The transmit error counter has exceeded the errorpassive limit of 127 and the device has gone to
error-passive state.
23.15.6.6
Bus-Off
The transmit error counter has exceeded 255 and the
device has gone to bus-off state.
23.15.6.7
Interrupt Acknowledge
Interrupts are directly associated with one or more status flags in the PIR register. Interrupts are pending as
long as one of the flags is set. Once an interrupt flag is
set by the device, the flag can not be reset by the
microcontroller until the interrupt condition is removed.
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NOTES:
DS30491D-page 344
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24.0
SPECIAL FEATURES OF THE
CPU
There are several features intended to maximize system reliability, minimize cost through elimination of
external components, provide power saving operating
modes and offer code protection. These are:
• OSC Selection
• Reset
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• Sleep
• Code Protection
• ID Locations
• In-Circuit Serial Programming
All PIC18F6585/8585/6680/8680 devices have a
Watchdog Timer which is permanently enabled via the
configuration bits or software controlled. It runs off its
own RC oscillator for added reliability. There are two
timers that offer necessary delays on power-up. One is
the Oscillator Start-up Timer (OST), intended to keep
the chip in Reset until the crystal oscillator is stable.
The other is the Power-up Timer (PWRT) which provides a fixed delay on power-up only, designed to keep
the part in Reset while the power supply stabilizes. With
these two timers on-chip, most applications need no
external Reset circuitry.
24.1
Configuration Bits
The configuration bits can be programmed (read as ‘0’)
or left unprogrammed (read as ‘1’) to select various
device configurations. These bits are mapped, starting
at program memory location 300000h.
The user will note that address 300000h is beyond the
user program memory space. In fact, it belongs to the
configuration memory space (300000h through
3FFFFFh) which can only be accessed using table
reads and table writes.
Programming the Configuration registers is done in a
manner similar to programming the Flash memory. The
EECON1 register WR bit starts a self-timed write to the
Configuration register. In normal Operation mode, a
TBLWT instruction with the TBLPTR pointed to the Configuration register sets up the address and the data for
the Configuration register write. Setting the WR bit
starts a long write to the Configuration register. The
Configuration registers are written a byte at a time. To
write or erase a configuration cell, a TBLWT instruction
can write a ‘1’ or a ‘0’ into the cell.
Sleep mode is designed to offer a very low current
Power-down mode. The user can wake-up from Sleep
through external Reset, Watchdog Timer Wake-up, or
through an interrupt. Several oscillator options are also
made available to allow the part to fit the application.
The RC oscillator option saves system cost, while the
LP crystal option saves power. A set of configuration
bits is used to select various options.
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TABLE 24-1:
CONFIGURATION BITS AND DEVICE IDS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default/
Unprogrammed
Value
--1- 1111
300001h
CONFIG1H
—
—
OSCSEN
—
FOSC3
FOSC2
FOSC1
FOSC0
300002h
CONFIG2L
—
—
—
—
BORV1
BORV0
BODEN
PWRTEN
---- 1111
300003h
CONFIG2H
—
—
—
WDTPS1
WDTPS0
WDTEN
---1 1111
WAIT
PM1
PM0
300004h(1) CONFIG3L
WDTPS3 WDTPS2
—
—
—
—
—
CONFIG3H MCLRE
—
—
—
—
—
300006h
CONFIG4L
DEBUG
—
—
—
—
LVP
—
STVREN
300008h
CONFIG5L
—
—
—
—
CP3(2)
CP2
CP1
CP0
---- 1111
300009h
CONFIG5H
CPD
CPB
—
—
—
—
—
—
11-- ----
30000Ah
CONFIG6L
—
—
—
—
WRT3(2)
WRT2
WRT1
WRT0
---- 1111
30000Bh
CONFIG6H
WRTD
WRTB
WRTC
—
—
—
—
—
111- ----
30000Ch
CONFIG7L
—
—
—
—
EBTR3(2)
EBTR2
EBTR1
EBTR0
---- 1111
30000Dh
CONFIG7H
—
EBTRB
—
—
—
—
—
—
-1-- ----
300005h
ECCPMX(4) CCP2MX
1--- --11
1--- --11
1--- -1-1
3FFFFEh DEVID1
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
(Note 3)
3FFFFFh
DEVID2
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
0000 1010
Legend:
x = unknown, u = unchanged, - = unimplemented, q = value depends on condition.
Shaded cells are unimplemented, read as ‘0’.
Unimplemented in PIC18F6X8X devices; maintain this bit set.
Unimplemented in PIC18FX585 devices; maintain this bit set.
See Register 24-13 for DEVID1 values.
Reserved in PIC18F6X8X devices; maintain this bit set.
Note 1:
2:
3:
4:
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REGISTER 24-1:
CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
U-0
U-0
R/P-1
U-0
R/P-1
R/P-1
R/P-1
R/P-1
—
—
OSCSEN
—
FOSC3
FOSC2
FOSC1
FOSC0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5
OSCSEN: Oscillator System Clock Switch Enable bit
1 = Oscillator system clock switch option is disabled (main oscillator is source)
0 = Timer1 oscillator system clock switch option is enabled (oscillator switching is enabled)
bit 4
Unimplemented: Read as ‘0’
bit 3-0
FOSC3:FOSC0: Oscillator Selection bits
1111 = RC oscillator with OSC2 configured as RA6
1110 = HS oscillator with SW enabled 4x PLL
1101 = EC oscillator with OSC2 configured as RA6 and SW enabled 4x PLL
1100 = EC oscillator with OSC2 configured as RA6 and HW enabled 4x PLL
1011 = Reserved; do not use
1010 = Reserved; do not use
1001 = Reserved; do not use
1000 = Reserved; do not use
0111 = RC oscillator with OSC2 configured as RA6
0110 = HS oscillator with HW enabled 4x PLL
0101 = EC oscillator with OSC2 configured as RA6
0100 = EC oscillator with OSC2 configured as divide by 4 clock output
0011 = RC oscillator with OSC2 configured as divide by 4 clock output
0010 = HS oscillator
0001 = XT oscillator
0000 = LP oscillator
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
2003-2013 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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PIC18F6585/8585/6680/8680
REGISTER 24-2:
CONFIG2L: CONFIGURATION REGISTER 2 LOW (BYTE ADDRESS 300002h)
U-0
U-0
U-0
U-0
R/P-1
R/P-1
R/P-1
R/P-1
—
—
—
—
BORV1
BORV0
BOREN
PWRTEN
bit 7
bit 0
bit 7-4
Unimplemented: Read as ‘0’
bit 3-2
BORV1:BORV0: Brown-out Reset Voltage bits
11 = VBOR set to 2.0V
10 = VBOR set to 2.7V
01 = VBOR set to 4.2V
00 = VBOR set to 4.5V
bit 1
BOREN: Brown-out Reset Enable bit
1 = Brown-out Reset enabled
0 = Brown-out Reset disabled
bit 0
PWRTEN: Power-up Timer Enable bit
1 = PWRT disabled
0 = PWRT enabled
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
DS30491D-page 348
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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PIC18F6585/8585/6680/8680
REGISTER 24-3:
CONFIG2H: CONFIGURATION REGISTER 2 HIGH (BYTE ADDRESS 300003h)
U-0
U-0
U-0
R/P-1
R/P-1
R/P-1
R/P-1
R/P-1
—
—
—
WDTPS3
WDTPS2
WDTPS1
WDTPS0
WDTEN
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-1
WDTPS3:WDTPS0: Watchdog Timer Postscaler Select bits
1111 = 1:32768
1110 = 1:16384
1101 = 1:8192
1100 = 1:4096
1011 = 1:2048
1010 = 1:1024
1001 = 1:512
1000 = 1:256
0111 = 1:128
0110 = 1:64
0101 = 1:32
0100 = 1:16
0011 = 1:8
0010 = 1:4
0001 = 1:2
0000 = 1:1
bit 0
WDTEN: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled (control is placed on the SWDTEN bit)
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
REGISTER 24-4:
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
CONFIG3L: CONFIGURATION REGISTER 3 LOW (BYTE ADDRESS 300004h)(1)
R/P-1
U-0
U-0
U-0
U-0
U-0
R/P-1
R/P-1
WAIT
—
—
—
—
—
PM1
PM0
bit 7
bit 0
bit 7
WAIT: External Bus Data Wait Enable bit
1 = Wait selections unavailable for table reads and table writes
0 = Wait selections for table reads and table writes are determined by WAIT1:WAIT0 bits
(MEMCOM)
bit 6-2
Unimplemented: Read as ‘0’
bit 1-0
PM1:PM0: Processor Mode Select bits
11 = Microcontroller mode
10 = Microprocessor mode
01 = Microprocessor with Boot Block mode
00 = Extended Microcontroller mode
Note 1: This register is unimplemented for PIC18F6X8X devices; maintain these bits set.
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
2003-2013 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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REGISTER 24-5:
CONFIG3H: CONFIGURATION REGISTER 3 HIGH (BYTE ADDRESS 300005h)
R/P-1
U-0
U-0
U-0
U-0
U-0
R/P-1
R/P-1
MCLRE
—
—
—
—
—
ECCPMX
CCP2MX
bit 7
bit 0
bit 7
MCLRE: MCLR Enable bit(1)
1 = MCLR pin enabled, RG5 input pin disabled
0 = RG5 input enabled, MCLR disabled
bit 6-2
Unimplemented: Read as ‘0’
bit 1
ECCPMX: CCP1 PWM outputs P1B, P1C mux bit (PIC18F8X8X devices only)(2)
1 = P1B, P1C are multiplexed with RE6, RE5
0 = P1B, P1C are multiplexed with RH7, RH6
bit 0
CCP2MX: CCP2 Mux bit
In Microcontroller mode:
1 = CCP2 input/output is multiplexed with RC1
0 = CCP2 input/output is multiplexed with RE7
In Microprocessor, Microprocessor with Boot Block and Extended Microcontroller modes
(PIC18F8X8X devices only):
1 = CCP2 input/output is multiplexed with RC1
0 = CCP2 input/output is multiplexed with RB3
Note 1: If MCLR is disabled, either disable low-voltage ICSP or hold RB5/PGM low to
ensure proper entry into ICSP mode.
2: Reserved for PIC18F6X8X devices; maintain this bit set.
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
REGISTER 24-6:
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
CONFIG4L: CONFIGURATION REGISTER 4 LOW (BYTE ADDRESS 300006h)
R/P-1
U-0
U-0
U-0
U-0
R/P-1
U-0
R/P-1
DEBUG
—
—
—
—
LVP
—
STVREN
bit 7
bit 0
bit 7
DEBUG: Background Debugger Enable bit
1 = Background debugger disabled. RB6 and RB7 configured as general purpose I/O pins.
0 = Background debugger enabled. RB6 and RB7 are dedicated to in-circuit debug.
bit 6-3
Unimplemented: Read as ‘0’
bit 2
LVP: Low-Voltage ICSP Enable bit
1 = Low-voltage ICSP enabled
0 = Low-voltage ICSP disabled
bit 1
Unimplemented: Read as ‘0’
bit 0
STVREN: Stack Full/Underflow Reset Enable bit
1 = Stack full/underflow will cause Reset
0 = Stack full/underflow will not cause Reset
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
DS30491D-page 350
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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REGISTER 24-7:
CONFIG5L: CONFIGURATION REGISTER 5 LOW (BYTE ADDRESS 300008h)
U-0
U-0
U-0
U-0
R/C-1
R/C-1
R/C-1
R/C-1
—
—
—
—
CP3(1)
CP2
CP1
CP0
bit 7
bit 7-4
bit 3
bit 2
bit 1
bit 0
bit 0
Unimplemented: Read as ‘0’
CP3: Code Protection bit(1)
1 = Block 3 (00C000-00FFFFh) not code-protected
0 = Block 3 (00C000-00FFFFh) code-protected
Note 1: Unimplemented in PIC18FX585 devices; maintain this bit set.
CP2: Code Protection bit
1 = Block 2 (008000-00BFFFh) not code-protected
0 = Block 2 (008000-00BFFFh) code-protected
CP1: Code Protection bit
1 = Block 1 (004000-007FFFh) not code-protected
0 = Block 1 (004000-007FFFh) code-protected
CP0: Code Protection bit
1 = Block 0 (000800-003FFFh) not code-protected
0 = Block 0 (000800-003FFFh) code-protected
Legend:
R = Readable bit
C = Clearable bit
- n = Value when device is unprogrammed
REGISTER 24-8:
CONFIG5H: CONFIGURATION REGISTER 5 HIGH (BYTE ADDRESS 300009h)
R/C-1
CPD
bit 7
bit 7
bit 6
bit 5-0
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
R/C-1
CPB
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
U-0
—
bit 0
CPD: Data EEPROM Code Protection bit
1 = Data EEPROM not code-protected
0 = Data EEPROM code-protected
CPB: Boot Block Code Protection bit
1 = Boot block (000000-0007FFh) not code-protected
0 = Boot block (000000-0007FFh) code-protected
Unimplemented: Read as ‘0’
Legend:
R = Readable bit
C = Clearable bit
- n = Value when device is unprogrammed
2003-2013 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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PIC18F6585/8585/6680/8680
REGISTER 24-9:
CONFIG6L: CONFIGURATION REGISTER 6 LOW (BYTE ADDRESS 30000Ah)
U-0
U-0
U-0
U-0
R/C-1
R/C-1
R/C-1
R/C-1
—
—
—
—
WRT3(1)
WRT2
WRT1
WRT0
bit 7
bit 0
bit 7-4
Unimplemented: Read as ‘0’
bit 3
WRT3: Write Protection bit(1)
1 = Block 3 (00C000-00FFFFh) not write-protected
0 = Block 3 (00C000-00FFFFh) write-protected
bit 2
WRT2: Write Protection bit
1 = Block 2 (008000-00BFFFh) not write-protected
0 = Block 2 (008000-00BFFFh) write-protected
bit 1
WRT1: Write Protection bit
1 = Block 1 (004000-007FFFh) not write-protected
0 = Block 1 (004000-007FFFh) write-protected
bit 0
WR0: Write Protection bit
1 = Block 0 (000800-003FFFh) not write-protected
0 = Block 0 (000800-003FFFh) write-protected
Note 1: Unimplemented in PIC18FX585 devices; maintain this bit set.
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 24-10: CONFIG6H: CONFIGURATION REGISTER 6 HIGH (BYTE ADDRESS 30000Bh)
R/C-1
R/C-1
R/C-1
U-0
U-0
U-0
U-0
U-0
WRTD
WRTB
WRTC
—
—
—
—
—
bit 7
bit 0
bit 7
WRTD: Data EEPROM Write Protection bit
1 = Data EEPROM not write-protected
0 = Data EEPROM write-protected
bit 6
WRTB: Boot Block Write Protection bit
1 = Boot block (000000-0007FFh) not write-protected
0 = Boot block (000000-0007FFh) write-protected
bit 5
WRTC: Configuration Register Write Protection bit
1 = Configuration registers (300000-3000FFh) not write-protected
0 = Configuration registers (300000-3000FFh) write-protected
bit 4-0
Unimplemented: Read as ‘0’
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
DS30491D-page 352
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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REGISTER 24-11: CONFIG7L: CONFIGURATION REGISTER 7 LOW (BYTE ADDRESS 30000Ch)
U-0
U-0
U-0
U-0
R/C-1
R/C-1
R/C-1
R/C-1
—
—
—
—
EBTR3(1)
EBTR2
EBTR1
EBTR0
bit 7
bit 0
bit 7-4
Unimplemented: Read as ‘0’
bit 3
EBTR3: Table Read Protection bit(1)
1 = Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks
0 = Block 3 (00C000-00FFFFh) protected from table reads executed in other blocks
bit 2
EBTR2: Table Read Protection bit
1 = Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks
0 = Block 2 (008000-00BFFFh) protected from table reads executed in other blocks
bit 1
EBTR1: Table Read Protection bit
1 = Block 1 (004000-007FFFh) not protected from table reads executed in other blocks
0 = Block 1 (004000-007FFFh) protected from table reads executed in other blocks
bit 0
EBTR0: Table Read Protection bit
1 = Block 0 (000800-003FFFh) not protected from table reads executed in other blocks
0 = Block 0 (000800-003FFFh) protected from table reads executed in other blocks
Note 1: Unimplemented in PIC18FX585 devices; maintain this bit set.
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 24-12: CONFIG7H: CONFIGURATION REGISTER 7 HIGH (BYTE ADDRESS 30000Dh)
U-0
R/C-1
U-0
U-0
U-0
U-0
U-0
U-0
—
EBTRB
—
—
—
—
—
—
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
EBTRB: Boot Block Table Read Protection bit
1 = Boot block (000000-0007FFh) not protected from table reads executed in other blocks
0 = Boot block (000000-0007FFh) protected from table reads executed in other blocks
bit 5-0
Unimplemented: Read as ‘0’
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
2003-2013 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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PIC18F6585/8585/6680/8680
REGISTER 24-13: DEVICE ID REGISTER 1 FOR PIC18FXX8X DEVICES (ADDRESS 3FFFFEh)
R
R
R
R
R
R
R
R
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
bit 7
bit 0
bit 7-5
DEV2:DEV0: Device ID bits
000 = PIC18F8680
001 = PIC18F6680
010 = PIC18F8585
011 = PIC18F6585
bit 4-0
REV4:REV0: Revision ID bits
These bits are used to indicate the device revision.
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 24-14: DEVICE ID REGISTER 2 FOR PIC18FXX8X DEVICES (ADDRESS 3FFFFFh)
R-0
R-0
R-0
R-0
R-1
R-0
R-1
R-0
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
bit 7
bit 7-0
bit 0
DEV10:DEV3: Device ID bits
These bits are used with the DEV2:DEV0 bits in the Device ID Register 1 to identify the
part number.
0000 1010 = PIC18F6585/8585/6680/8680
Legend:
R = Readable bit
P = Programmable bit
- n = Value when device is unprogrammed
DS30491D-page 354
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
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24.2
Watchdog Timer (WDT)
The Watchdog Timer is a free-running, on-chip RC
oscillator which does not require any external components. This RC oscillator is separate from the RC
oscillator of the OSC1/CLKI pin. That means that the
WDT will run even if the clock on the OSC1/CLKI and
OSC2/CLKO/RA6 pins of the device has been stopped,
for example, by execution of a SLEEP instruction.
The WDT time-out period values may be found in
Section 27.0 “Electrical Characteristics” under
parameter #31. Values for the WDT postscaler may be
assigned using the configuration bits.
Note 1: The CLRWDT and SLEEP instructions
clear the WDT and the postscaler if
assigned to the WDT and prevent it from
timing out and generating a device Reset
condition.
During normal operation, a WDT time-out generates a
device Reset (Watchdog Timer Reset). If the device is
in Sleep mode, a WDT time-out causes the device to
wake-up and continue with normal operation (Watchdog Timer wake-up). The TO bit in the RCON register
will be cleared upon a WDT time-out.
The Watchdog Timer is enabled/disabled by a device
configuration bit. If the WDT is enabled, software
execution may not disable this function. When the
WDTEN configuration bit is cleared, the SWDTEN bit
enables/disables the operation of the WDT.
2: When a CLRWDT instruction is executed
and the postscaler is assigned to the
WDT, the postscaler count will be cleared
but the postscaler assignment is not
changed.
24.2.1
CONTROL REGISTER
Register 24-15 shows the WDTCON register. This is a
readable and writable register which contains a control
bit that allows software to override the WDT enable
configuration bit, only when the configuration bit has
disabled the WDT.
REGISTER 24-15: WDTCON REGISTER
U-0
U-0
U-0
U-0
U-0
U-0
U-0
R/W-0
—
—
—
—
—
—
—
SWDTEN
bit 7
bit 0
bit 7-1
Unimplemented: Read as ‘0’
bit 0
SWDTEN: Software Controlled Watchdog Timer Enable bit
1 = Watchdog Timer is on
0 = Watchdog Timer is turned off if the WDTEN configuration bit in the Configuration register = 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
2003-2013 Microchip Technology Inc.
x = Bit is unknown
DS30491D-page 355
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PIC18F6585/8585/6680/8680
24.2.2
WDT POSTSCALER
The WDT has a postscaler that can extend the WDT
Reset period. The postscaler is selected at the time of
the device programming by the value written to the
CONFIG2H Configuration register.
FIGURE 24-1:
WATCHDOG TIMER BLOCK DIAGRAM
WDT Timer
Postscaler
16
WDTPS3:WDTPS0
16-to-1 MUX
WDTEN
Configuration bit
SWDTEN bit
WDT
Time-out
Note:
TABLE 24-2:
WDPS3:WDPS0 are bits in register CONFIG2H.
SUMMARY OF WATCHDOG TIMER REGISTERS
Name
CONFIG2H
RCON
WDTCON
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
—
—
—
WDTPS3
WDTPS2
WDTPS2
WDTPS0
WDTEN
IPEN
—
—
RI
TO
PD
POR
BOR
—
—
—
—
—
—
—
SWDTEN
Legend: Shaded cells are not used by the Watchdog Timer.
DS30491D-page 356
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24.3
Power-down Mode (Sleep)
Power-down mode is entered by executing a SLEEP
instruction.
If enabled, the Watchdog Timer will be cleared but
keeps running, the PD bit (RCON) is cleared, the
TO (RCON) bit is set and the oscillator driver is
turned off. The I/O ports maintain the status they had
before the SLEEP instruction was executed (driving
high, low, or high-impedance).
For lowest current consumption in this mode, place all
I/O pins at either VDD or VSS, ensure no external circuitry is drawing current from the I/O pin, power-down
the A/D and disable external clocks. Pull all I/O pins
that are high-impedance inputs, high or low externally
to avoid switching currents caused by floating inputs.
The T0CKI input should also be at VDD or VSS for lowest current consumption. The contribution from on-chip
pull-ups on PORTB should be considered.
The MCLR pin must be at a logic high level (VIHMC).
24.3.1
WAKE-UP FROM SLEEP
Other peripherals cannot generate interrupts since
during Sleep, no on-chip clocks are present.
External MCLR Reset will cause a device Reset. All
other events are considered a continuation of program
execution and will cause a “wake-up”. The TO and PD
bits in the RCON register can be used to determine the
cause of the device Reset. The PD bit which is set on
power-up is cleared when Sleep is invoked. The TO bit
is cleared if a WDT time-out occurred (and caused
wake-up).
When the SLEEP instruction is being executed, the next
instruction (PC + 2) is pre-fetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up is
regardless of the state of the GIE bit. If the GIE bit is
clear (disabled), the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
set (enabled), the device executes the instruction after
the SLEEP instruction and then branches to the interrupt address. In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOP after the SLEEP instruction.
The device can wake-up from Sleep through one of the
following events:
24.3.2
1.
2.
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:
3.
External Reset input on MCLR pin.
Watchdog Timer Wake-up (if WDT was
enabled).
Interrupt from INT pin, RB port change or a
peripheral interrupt.
The following peripheral interrupts can wake the device
from Sleep:
1.
2.
PSP read or write.
TMR1 interrupt. Timer1 must be operating as an
asynchronous counter.
3. TMR3 interrupt. Timer3 must be operating as an
asynchronous counter.
4. CCP Capture mode interrupt.
5. Special event trigger (Timer1 in Asynchronous
mode using an external clock).
6. MSSP (Start/Stop) bit detect interrupt.
7. MSSP transmit or receive in Slave mode
(SPI/I2C).
8. USART RX or TX (Synchronous Slave mode).
9. A/D conversion (when A/D clock source is RC).
10. EEPROM write operation complete.
11. LVD interrupt.
12. CAN wake-up interrupt.
2003-2013 Microchip Technology Inc.
WAKE-UP USING INTERRUPTS
• If an interrupt condition (interrupt flag bit and
interrupt enable bits are set) occurs before the
execution of a SLEEP instruction, the SLEEP
instruction will complete as a NOP. Therefore, the
WDT and WDT postscaler will not be cleared, the
TO bit will not be set and PD bits will not be
cleared.
• If the interrupt condition occurs during or after
the execution of a SLEEP instruction, the device
will immediately wake-up from Sleep. The SLEEP
instruction will be completely executed before the
wake-up. Therefore, the WDT and WDT
postscaler will be cleared, the TO bit will be set
and the PD bit will be cleared.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT
instruction should be executed before a SLEEP
instruction.
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WAKE-UP FROM SLEEP THROUGH INTERRUPT(1,2)
FIGURE 24-2:
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
TOST(2)
CLKO(4)
INT pin
INTF Flag
(INTCON)
Interrupt Latency(3)
GIEH bit
(INTCON)
Processor in
Sleep
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
Note
1:
2:
3:
4:
PC
PC+2
Inst(PC) = Sleep
Inst(PC + 2)
Inst(PC - 1)
Sleep
PC+4
PC+4
PC + 4
Inst(PC + 4)
Inst(PC + 2)
Dummy Cycle
0008h
000Ah
Inst(0008h)
Inst(000Ah)
Dummy Cycle
Inst(0008h)
XT, HS or LP Oscillator mode assumed.
GIE = 1 assumed. In this case after wake-up, the processor jumps to the interrupt routine. If GIE = 0, execution will continue in-line.
TOST = 1024 TOSC (drawing not to scale). This delay will not occur for RC and EC Oscillator modes.
CLKO is not available in these oscillator modes but shown here for timing reference.
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24.4
Program Verification and
Code Protection
Figure 24-3 shows the program memory organization
for 48 and 64-Kbyte devices and the specific code
protection bit associated with each block. The actual
locations of the bits are summarized in Table 24-3.
The overall structure of the code protection on the
PIC18 Flash devices differs significantly from other
PIC® devices.
The user program memory is divided on binary boundaries into four blocks of 16 Kbytes each. The first block
is further divided into a boot block of 2048 bytes and a
second block (Block 0) of 14 Kbytes.
Each of the blocks has three code protection bits
associated with them. They are:
• Code-Protect bit (CPn)
• Write-Protect bit (WRTn)
• External Block Table Read bit (EBTRn)
FIGURE 24-3:
CODE-PROTECTED PROGRAM MEMORY FOR PIC18FXX8X DEVICES
MEMORY SIZE/DEVICE
Block Code Protection
Controlled By:
48 Kbytes
(PIC18FX585
64 Kbytes
(PIC18FX680)
Address
Range
Boot Block
Boot Block
000000h
0007FFh
CPB, WRTB, EBTRB
Block 0
Block 0
000800h
003FFFh
CP0, WRT0, EBTR0
004000h
Block 1
CP1, WRT1, EBTR1
Block 1
007FFFh
008000h
Block 2
CP2, WRT2, EBTR2
Block 2
00BFFFh
00C000h
Unimplemented Read ‘0’
CP3, WRT3, EBTR3
Block 3
00FFFFh
TABLE 24-3:
SUMMARY OF CODE PROTECTION REGISTERS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
300008h
CONFIG5L
—
—
—
—
CP3(1)
CP2
CP1
CP0
300009h
CONFIG5H
CPD
CPB
—
—
—
—
—
—
30000Ah
CONFIG6L
—
—
—
—
WRT3(1)
WRT2
WRT1
WRT0
30000Bh
CONFIG6H
WRTD
WRTB
WRTC
—
—
—
—
—
30000Ch
CONFIG7L
—
—
—
—
EBTR3(1)
EBTR2
EBTR1
EBTR0
30000Dh
CONFIG7H
—
EBTRB
—
—
—
—
—
—
Legend: Shaded cells are unimplemented.
Note 1: Unimplemented in PIC18FX585 devices.
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24.4.1
PROGRAM MEMORY
CODE PROTECTION
The user memory may be read to or written from any
location using the table read and table write instructions. The device ID may be read with table reads. The
Configuration registers may be read and written with
the table read and table write instructions.
that block is not allowed to read and will result in reading ‘0’s. Figures 24-4 through 24-6 illustrate table write
and table read protection.
Note:
In User mode, the CPn bits have no direct effect. CPn
bits inhibit external reads and writes. A block of user
memory may be protected from table writes if the
WRTn configuration bit is ‘0’. The EBTRn bits control
table reads. For a block of user memory with the
EBTRn bit set to ‘0’, a table read instruction that executes from within that block is allowed to read. A table
read instruction that executes from a location outside of
FIGURE 24-4:
Code protection bits may only be written to
a ‘0’ from a ‘1’ state. It is not possible to
write a ‘1’ to a bit in the ‘0’ state. Code
protection bits are only set to ‘1’ by a full
chip erase or block erase function. The full
chip erase and block erase functions can
only be initiated via ICSP or an external
programmer.
TABLE WRITE (WRTn) DISALLOWED
Register Values
Program Memory
Configuration Bit Settings
000000h
0007FFh
000800h
TBLPTR = 000FFFh
WRTB, EBTRB = 11
WRT0, EBTR0 = 01
PC = 003FFEh
TBLWT *
003FFFh
004000h
WRT1, EBTR1 = 11
007FFFh
008000h
PC = 008FFEh
WRT2, EBTR2 = 11
TBLWT *
00BFFFh
00C000h
WRT3, EBTR3 = 11
00FFFFh
Results: All table writes disabled to Block n whenever WRTn = 0.
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FIGURE 24-5:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Register Values
Program Memory
Configuration Bit Settings
000000h
0007FFh
000800h
TBLPTR = 000FFFh
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
003FFFh
004000h
PC = 004FFEh
TBLRD *
WRT1, EBTR1 = 11
007FFFh
008000h
WRT2, EBTR2 = 11
00BFFFh
00C000h
WRT3, EBTR3 = 11
00FFFFh
Results: All table reads from external blocks to Block n are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
FIGURE 24-6:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
Program Memory
Configuration Bit Settings
000000h
0007FFh
000800h
TBLPTR = 000FFFh
PC = 003FFEh
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
TBLRD *
003FFFh
004000h
WRT1, EBTR1 = 11
007FFFh
008000h
WRT2, EBTR2 = 11
00BFFFh
00C000h
WRT3, EBTR3 = 11
00FFFFh
Results: Table reads permitted within Block n even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
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24.4.2
DATA EEPROM CODE
PROTECTION
The entire data EEPROM is protected from external
reads and writes by two bits: CPD and WRTD. CPD
inhibits external reads and writes of data EEPROM.
WRTD inhibits external writes to data EEPROM. The
CPU can continue to read and write data EEPROM
regardless of the protection bit settings.
24.4.3
CONFIGURATION REGISTER
PROTECTION
The Configuration registers can be write-protected. The
WRTC bit controls protection of the Configuration registers. In User mode, the WRTC bit is readable only. WRTC
can only be written via ICSP or an external programmer.
24.5
ID Locations
Eight memory locations (200000h-200007h) are
designated as ID locations where the user can store
checksum or other code identification numbers. These
locations are accessible during normal execution
through the TBLRD and TBLWT instructions or during
program/verify. The ID locations can be read when the
device is code-protected.
24.6
24.7
In-Circuit Debugger
When the DEBUG bit in Configuration register,
CONFIG4L, is programmed to a ‘0’, the in-circuit
debugger functionality is enabled. This function allows
simple debugging functions when used with MPLAB®
IDE. When the microcontroller has this feature
enabled, some of the resources are not available for
general use. Table 24-4 shows which features are
consumed by the background debugger.
TABLE 24-4:
DEBUGGER RESOURCES
I/O pins
Stack
RB6, RB7
2 levels
Program Memory
512 bytes
Data Memory
10 bytes
To use the in-circuit debugger function of the microcontroller, the design must implement In-Circuit Serial
Programming connections to MCLR/VPP, VDD, GND,
RB7 and RB6. This will interface to the in-circuit
debugger module available from Microchip or one of
the third party development tool companies.
In-Circuit Serial Programming
PIC18FXX80/XX85 microcontrollers can be serially
programmed while in the end application circuit. This is
simply done with two lines for clock and data, and three
other lines for power, ground and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
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24.8
Low-Voltage ICSP Programming
The LVP bit in Configuration register, CONFIG4L,
enables Low-Voltage ICSP Programming. This mode
allows the microcontroller to be programmed via ICSP
using a VDD source in the operating voltage range. This
only means that VPP does not have to be brought to VIHH
but can instead be left at the normal operating voltage.
In this mode, the RB5/KBI1/PGM pin is dedicated to the
programming function and ceases to be a general purpose I/O pin. During programming, VDD is applied to the
RG5/MCLR/VPP pin. To enter Programming mode, VDD
must be applied to the RB5/KBI1/PGM pin, provided the
LVP bit is set. The LVP bit defaults to a ‘1’ from the
factory.
Note 1: The High-Voltage Programming mode is
always available regardless of the state of
the LVP bit, by applying VIHH to the MCLR
pin.
If Low-Voltage Programming mode is not used, the LVP
bit can be programmed to a ‘0’ and RB5/KBI1/PGM
becomes a digital I/O pin. However, the LVP bit may
only be programmed when programming is entered
with VIHH on RG5/MCLR/VPP.
It should be noted that once the LVP bit is programmed
to ‘0’, only the High-Voltage Programming mode is
available and only High-Voltage Programming mode
can be used to program the device.
When using low-voltage ICSP, the part must be supplied 4.5V to 5.5V if a bulk erase will be executed. This
includes reprogramming of the code-protect bits from
an on-state to an off-state. For all other cases of lowvoltage ICSP, the part may be programmed at the
normal operating voltage. This means unique user IDs
or user code can be reprogrammed or added.
2: While in Low-Voltage ICSP mode, the
RB5 pin can no longer be used as a
general purpose I/O pin and should be
held low during normal operation.
3: When using Low-Voltage ICSP Programming (LVP) and the pull-ups on PORTB
are enabled, bit 5 in the TRISB register
must be cleared to disable the pull-up on
RB5 and ensure the proper operation of
the device.
4: If the device Master Clear is disabled,
verify that either of the following is done to
ensure proper entry into ICSP mode:
a) disable Low-Voltage Programming
(CONFIG4L = 0); or
b) make certain that RB5/KBI1/PGM is
held low during entry into ICSP.
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NOTES:
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25.0
INSTRUCTION SET SUMMARY
The PIC18 instruction set adds many enhancements to
the previous PIC MCU instruction sets, while maintaining an easy migration from these PIC MCU instruction
sets.
Most instructions are a single program memory word
(16 bits) but there are three instructions that require two
program memory locations.
Each single-word instruction is a 16-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 instruction set is highly orthogonal and is grouped
into four basic categories:
•
•
•
•
Byte-oriented operations
Bit-oriented operations
Literal operations
Control operations
The PIC18 instruction set summary in Table 25-2 lists
byte-oriented, bit-oriented, literal and control
operations. Table 25-1 shows the opcode field
descriptions.
Most byte-oriented instructions have three operands:
1.
2.
3.
The file register (specified by ‘f’)
The destination of the result (specified by ‘d’)
The accessed memory (specified by ‘a’)
The file register designator ‘f’ specifies which file
register is to be used by the instruction.
The destination designator ‘d’ specifies where the
result of the operation is to be placed. If ‘d’ is zero, the
result is placed in the WREG register. If ‘d’ is one, the
result is placed in the file register specified in the
instruction.
All bit-oriented instructions have three operands:
1.
2.
3.
The file register (specified by ‘f’)
The bit in the file register (specified by ‘b’)
The accessed memory (specified by ‘a’)
The bit field designator ‘b’ selects the number of the bit
affected by the operation, while the file register designator ‘f’ represents the number of the file in which the
bit is located.
The literal instructions may use some of the following
operands:
• A literal value to be loaded into a file register
(specified by ‘k’)
• The desired FSR register to load the literal value
into (specified by ‘f’)
• No operand required (specified by ‘—’)
The control instructions may use some of the following
operands:
• A program memory address (specified by ‘n’)
• The mode of the call or return instructions
(specified by ‘s’)
• The mode of the table read and table write
instructions (specified by ‘m’)
• No operand required (specified by ‘—’)
All instructions are a single word except for three
double-word instructions. These three instructions
were made double-word instructions so that all the
required information is available in these 32 bits. In the
second word, the 4 MSbs are ‘1’s. If this second word
is executed as an instruction (by itself), it will execute
as a NOP.
All single-word instructions are executed in a single
instruction cycle unless a conditional test is true or the
program counter is changed as a result of the instruction. In these cases, the execution takes two instruction
cycles with the additional instruction cycle(s) executed
as a NOP.
The double-word instructions execute in two instruction
cycles.
One instruction cycle consists of four oscillator periods.
Thus, for an oscillator frequency of 4 MHz, the normal
instruction execution time is 1 s. If a conditional test is
true or the program counter is changed as a result of an
instruction, the instruction execution time is 2 s.
Two-word branch instructions (if true) would take 3 s.
Figure 25-1 shows the general formats that the
instructions can have.
All examples use the format ‘nnh’ to represent a hexadecimal number, where ‘h’ signifies a hexadecimal
digit.
The Instruction Set Summary, shown in Table 25-2,
lists the instructions recognized by the Microchip
Assembler (MPASMTM).
Section 25.1 “Instruction Set” provides a description
of each instruction.
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TABLE 25-1:
OPCODE FIELD DESCRIPTIONS
Field
Description
a
RAM access bit
a = 0: RAM location in Access RAM (BSR register is ignored)
a = 1: RAM bank is specified by BSR register
bbb
Bit address within an 8-bit file register (0 to 7).
BSR
Bank Select Register. Used to select the current RAM bank.
d
Destination select bit
d = 0: store result in WREG
d = 1: store result in file register f
dest
Destination either the WREG register or the specified register file location.
f
8-bit register file address (0x00 to 0xFF).
fs
12-bit register file address (0x000 to 0xFFF). This is the source address.
fd
12-bit register file address (0x000 to 0xFFF). This is the destination address.
k
Literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value).
label
Label name.
mm
The mode of the TBLPTR register for the table read and table write instructions.
Only used with table read and table write instructions:
*
No change to register (such as TBLPTR with table reads and writes).
*+
Post-Increment register (such as TBLPTR with table reads and writes).
*-
Post-Decrement register (such as TBLPTR with table reads and writes).
Pre-Increment register (such as TBLPTR with table reads and writes).
+*
n
The relative address (2’s complement number) for relative branch instructions, or the direct address for
call/branch and return instructions.
PRODH
Product of Multiply High Byte.
PRODL
Product of Multiply Low Byte.
s
Fast Call/Return mode select bit
s = 0: do not update into/from shadow registers
s = 1: certain registers loaded into/from shadow registers (Fast mode)
u
Unused or unchanged.
WREG
Working register (accumulator).
x
Don’t care (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.
TBLPTR
21-bit Table Pointer (points to a program memory location).
TABLAT
8-bit Table Latch.
TOS
Top-of-Stack.
PC
Program Counter.
PCL
Program Counter Low Byte.
PCH
Program Counter High Byte.
PCLATH
Program Counter High Byte Latch.
PCLATU
Program Counter Upper Byte Latch.
GIE
Global Interrupt Enable bit.
WDT
Watchdog Timer.
TO
Time-out bit.
PD
Power-down bit.
C, DC, Z, OV, N
ALU status bits: Carry, Digit Carry, Zero, Overflow, Negative.
[
]
Optional.
(
)
Contents.
Assigned to.
< >
Register bit field.
In the set of.
italics
User defined term (font is courier).
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FIGURE 25-1:
GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations
15
10
9 8 7
OPCODE d
a
Example Instruction
0
f (FILE #)
ADDWF MYREG, W, B
d = 0 for result destination to be WREG register
d = 1 for result destination to be file register (f)
a = 0 to force Access Bank
a = 1 for BSR to select bank
f = 8-bit file register address
Byte to Byte move operations (2-word)
15
12 11
OPCODE
15
0
f (Source FILE #)
12 11
MOVFF MYREG1, MYREG2
0
f (Destination FILE #)
1111
f = 12-bit file register address
Bit-oriented file register operations
15
12 11
9 8 7
OPCODE b (BIT #) a
0
f (FILE #)
BSF MYREG, bit, B
b = 3-bit position of bit in file register (f)
a = 0 to force Access Bank
a = 1 for BSR to select bank
f = 8-bit file register address
Literal operations
15
8
7
OPCODE
0
k (literal)
MOVLW 0x7F
k = 8-bit immediate value
Control operations
CALL, GOTO and Branch operations
15
8 7
OPCODE
15
0
n (literal)
12 11
GOTO Label
0
n (literal)
1111
n = 20-bit immediate value
15
8 7
OPCODE
15
S
0
CALL MYFUNC
n (literal)
12 11
0
n (literal)
S = Fast bit
15
11 10
OPCODE
15
OPCODE
2003-2013 Microchip Technology Inc.
0
BRA MYFUNC
n (literal)
8 7
n (literal)
0
BC MYFUNC
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TABLE 25-2:
PIC18FXXX INSTRUCTION SET
Mnemonic,
Operands
16-Bit Instruction Word
Description
Cycles
MSb
LSb
Status
Affected
Notes
BYTE-ORIENTED FILE REGISTER OPERATIONS
0010 01da ffff ffff C, DC, Z, OV, N 1, 2
1
ADDWF f, d, a Add WREG and f
0010 00da ffff ffff C, DC, Z, OV, N 1, 2
1
ADDWFC f, d, a Add WREG and Carry bit to f
1,2
0001 01da ffff ffff Z, N
1
ANDWF f, d, a AND WREG with f
2
0110 101a ffff ffff Z
f, a
1
Clear f
CLRF
1, 2
0001 11da ffff ffff Z, N
f, d, a Complement f
1
COMF
4
1 (2 or 3) 0110 001a ffff ffff None
Compare f with WREG, Skip =
CPFSEQ f, a
4
1 (2 or 3) 0110 010a ffff ffff None
Compare f with WREG, Skip >
CPFSGT f, a
1, 2
1 (2 or 3) 0110 000a ffff ffff None
Compare f with WREG, Skip <
CPFSLT f, a
0000 01da ffff ffff C, DC, Z, OV, N 1, 2, 3, 4
f, d, a Decrement f
1
DECF
1, 2, 3, 4
1 (2 or 3) 0010 11da ffff ffff None
DECFSZ f, d, a Decrement f, Skip if 0
1, 2
1 (2 or 3) 0100 11da ffff ffff None
DCFSNZ f, d, a Decrement f, Skip if Not 0
0010 10da ffff ffff C, DC, Z, OV, N 1, 2, 3, 4
f, d, a Increment f
1
INCF
4
1 (2 or 3) 0011 11da ffff ffff None
INCFSZ f, d, a Increment f, Skip if 0
1, 2
1 (2 or 3) 0100 10da ffff ffff None
INFSNZ f, d, a Increment f, Skip if Not 0
1, 2
0001 00da ffff ffff Z, N
f, d, a Inclusive OR WREG with f
1
IORWF
1
0101 00da ffff ffff Z, N
f, d, a Move f
1
MOVF
1100 ffff ffff ffff None
fs, fd Move fs (source) to 1st word
2
MOVFF
1111 ffff ffff ffff
fd (destination) 2nd word
0110 111a ffff ffff None
1
MOVWF f, a
Move WREG to f
0000 001a ffff ffff None
1
MULWF f, a
Multiply WREG with f
0110 110a ffff ffff C, DC, Z, OV, N 1, 2
1
NEGF
Negate f
f, a
0011 01da ffff ffff C, Z, N
1
RLCF
f, d, a Rotate Left f through Carry
0100 01da ffff ffff Z, N
1
RLNCF
f, d, a Rotate Left f (No Carry)
1, 2
0011 00da ffff ffff C, Z, N
1
RRCF
f, d, a Rotate Right f through Carry
0100 00da ffff ffff Z, N
1
RRNCF
f, d, a Rotate Right f (No Carry)
0110 100a ffff ffff None
1
SETF
Set f
f, a
0101 01da ffff ffff C, DC, Z, OV, N 1, 2
1
SUBFWB f, d, a Subtract f from WREG with
borrow
0101 11da ffff ffff C, DC, Z, OV, N
1
SUBWF f, d, a Subtract WREG from f
0101 10da ffff ffff C, DC, Z, OV, N 1, 2
1
SUBWFB f, d, a Subtract WREG from f with
borrow
0011 10da ffff ffff None
1
SWAPF f, d, a Swap nibbles in f
4
1 (2 or 3) 0110 011a ffff ffff None
TSTFSZ f, a
Test f, Skip if 0
1, 2
0001 10da ffff ffff Z, N
1
XORWF f, d, a Exclusive OR WREG with f
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
f, b, a Bit Clear f
1
1001 bbba ffff ffff None
1, 2
BSF
f, b, a Bit Set f
1
1000 bbba ffff ffff None
1, 2
BTFSC
f, b, a Bit Test f, Skip if Clear
1 (2 or 3) 1011 bbba ffff ffff None
3, 4
BTFSS
f, b, a Bit Test f, Skip if Set
1 (2 or 3) 1010 bbba ffff ffff None
3, 4
BTG
f, d, a Bit Toggle f
1
0111 bbba ffff ffff None
1, 2
Note 1: When a Port register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that
value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is
driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be
cleared if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP
unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that
all program memory locations have a valid instruction.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
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TABLE 25-2:
Mnemonic,
Operands
PIC18FXXX INSTRUCTION SET (CONTINUED)
16-Bit Instruction Word
Description
CONTROL OPERATIONS
Branch if Carry
n
BC
Branch if Negative
n
BN
Branch if Not Carry
n
BNC
Branch if Not Negative
n
BNN
Branch if Not Overflow
n
BNOV
Branch if Not Zero
n
BNZ
Branch if Overflow
n
BOV
Branch Unconditionally
n
BRA
Branch if Zero
n
BZ
Call subroutine 1st word
n, s
CALL
2nd word
Clear Watchdog Timer
CLRWDT —
Decimal Adjust WREG
—
DAW
Go to address 1st word
n
GOTO
2nd word
No Operation
—
NOP
No Operation
—
NOP
Pop top of return stack (TOS)
—
POP
Push top of return stack (TOS)
—
PUSH
Relative Call
n
RCALL
Software device Reset
RESET
Return from interrupt enable
RETFIE s
Cycles
MSb
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
2
1 (2)
2
1
1
2
1
1
1
1
2
1
2
1110
1110
1110
1110
1110
1110
1110
1101
1110
1110
1111
0000
0000
1110
1111
0000
1111
0000
0000
1101
0000
0000
LSb
0010
0110
0011
0111
0101
0001
0100
0nnn
0000
110s
kkkk
0000
0000
1111
kkkk
0000
xxxx
0000
0000
1nnn
0000
0000
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0000
0000
kkkk
kkkk
0000
xxxx
0000
0000
nnnn
1111
0001
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0100
0111
kkkk
kkkk
0000
xxxx
0110
0101
nnnn
1111
000s
Status
Affected
Notes
None
None
None
None
None
None
None
None
None
None
TO, PD
C
None
None
None
4
None
None
None
All
GIE/GIEH,
PEIE/GIEL
0000 1100 kkkk kkkk None
2
Return with literal in WREG
k
RETLW
0000 0000 0001 001s None
2
Return from Subroutine
RETURN s
0000 0000 0000 0011 TO, PD
1
Go into Standby mode
—
SLEEP
Note 1: When a Port register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that
value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is
driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be
cleared if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP
unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that
all program memory locations have a valid instruction.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
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TABLE 25-2:
PIC18FXXX INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands
16-Bit Instruction Word
Description
Cycles
MSb
LSb
Status
Affected
Notes
LITERAL OPERATIONS
kkkk C, DC, Z, OV, N
0000 1111 kkkk
1
Add literal and WREG
ADDLW k
kkkk Z, N
0000 1011 kkkk
1
AND literal with WREG
ANDLW k
kkkk Z, N
0000 1001 kkkk
Inclusive OR literal with WREG 1
k
IORLW
kkkk None
1110 1110 00ff
2
Move literal (12-bit) 2nd word
f, k
LFSR
kkkk
1111 0000 kkkk
to FSRx 1st word
kkkk None
0000 0001 0000
1
Move literal to BSR
MOVLB k
kkkk None
0000 1110 kkkk
1
Move literal to WREG
MOVLW k
kkkk None
0000 1101 kkkk
1
Multiply literal with WREG
MULLW k
kkkk None
0000 1100 kkkk
2
Return with literal in WREG
k
RETLW
kkkk C, DC, Z, OV, N
0000 1000 kkkk
1
Subtract WREG from literal
k
SUBLW
kkkk Z, N
0000 1010 kkkk
Exclusive OR literal with WREG 1
XORLW k
DATA MEMORY PROGRAM MEMORY OPERATIONS
1000 None
2
0000 0000 0000
Table Read
TBLRD*
1001 None
0000 0000 0000
Table Read with post-increment
TBLRD*+
1010 None
0000 0000 0000
Table Read with post-decrement
TBLRD*1011 None
0000 0000 0000
Table Read with pre-increment
TBLRD+*
1100 None
2 (5)
0000 0000 0000
Table Write
TBLWT*
1101 None
0000 0000 0000
Table Write with post-increment
TBLWT*+
1110 None
0000 0000 0000
Table Write with post-decrement
TBLWT*1111 None
0000 0000 0000
Table Write with pre-increment
TBLWT+*
Note 1: When a Port register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that
value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is
driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be
cleared if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP
unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that
all program memory locations have a valid instruction.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
DS30491D-page 370
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25.1
Instruction Set
ADDLW
ADD literal to W
Syntax:
[ label ] ADDLW
Operands:
0 k 255
Operation:
(W) + k W
Status Affected:
N, OV, C, DC, Z
Encoding:
0000
Description:
1111
kkkk
kkkk
The contents of W are added to the
8-bit literal ‘k’ and the result is
placed in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
ADDLW
0x15
Before Instruction
W
k
=
0x10
ADDWF
ADD W to f
Syntax:
[ label ] ADDWF
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(W) + (f) dest
Status Affected:
N, OV, C, DC, Z
Encoding:
0010
Description:
ffff
ffff
Add W to register ‘f’. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the
result is stored back in register ‘d’
(default). If ‘a’ is ‘0’, the Access
Bank will be selected. If ‘a’ is ‘1’,
the BSR is used.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
01da
f [,d [,a] f [,d [,a]
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
ADDWF
REG, 0, 0
After Instruction
W
=
0x25
Example:
Before Instruction
W
REG
=
=
0x17
0xC2
After Instruction
W
REG
2003-2013 Microchip Technology Inc.
=
=
0xD9
0xC2
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ADDWFC
ADD W and Carry bit to f
Syntax:
[ label ] ADDWFC
Operands:
0 f 255
d [0,1]
a [0,1]
f [,d [,a]]
Operation:
(W) + (f) + (C) dest
Status Affected:
N,OV, C, DC, Z
Encoding:
0010
Description:
1
Cycles:
1
AND literal with W
Syntax:
[ label ] ANDLW
Operands:
0 k 255
Operation:
(W) .AND. k W
Status Affected:
N, Z
Encoding:
ffff
ffff
Add W, the Carry Flag and data
memory location ‘f’. If ‘d’ is ‘0’, the
result is placed in W. If ‘d’ is ‘1’, the
result is placed in data memory location ‘f’. If ‘a’ is ‘0’, the Access Bank
will be selected. If ‘a’ is ‘1’, the BSR
will not be overridden.
Words:
0000
Description:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
ADDWFC
kkkk
kkkk
Q2
Q3
Q4
Read literal
‘k’
Process
Data
Write to W
ANDLW
0x5F
Before Instruction
W
=
0xA3
After Instruction
W
Example:
1011
k
The contents of W are ANDed with
the 8-bit literal ‘k’. The result is
placed in W.
Example:
Q Cycle Activity:
Q1
Decode
00da
ANDLW
=
0x03
REG, 0, 1
Before Instruction
Carry bit =
REG
=
W
=
1
0x02
0x4D
After Instruction
Carry bit =
REG
=
W
=
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0
0x02
0x50
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ANDWF
AND W with f
Syntax:
[ label ] ANDWF
Operands:
0 f 255
d [0,1]
a [0,1]
f [,d [,a]]
BC
Branch if Carry
Syntax:
[ label ] BC
Operands:
-128 n 127
Operation:
if carry bit is ‘1’
(PC) + 2 + 2n PC
None
Operation:
(W) .AND. (f) dest
Status Affected:
Status Affected:
N, Z
Encoding:
Encoding:
0001
Description:
01da
ffff
ffff
1110
Description:
Words:
1
Words:
1
Cycles:
1
Cycles:
1(2)
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
ANDWF
REG, 0, 0
Example:
Before Instruction
W
REG
=
=
0x17
0xC2
W
REG
=
=
Q Cycle Activity:
If Jump:
Q1
nnnn
nnnn
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1
Decode
After Instruction
0010
If the Carry bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
The contents of W are AND’ed with
register ‘f’. If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank will be
selected. If ‘a’ is ‘1’, the BSR will
not be overridden (default).
Q Cycle Activity:
Q1
n
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
0x02
0xC2
Example:
HERE
BC
5
Before Instruction
PC
=
address (HERE)
After Instruction
If Carry
PC
If Carry
PC
2003-2013 Microchip Technology Inc.
=
=
=
=
1;
address (HERE+12)
0;
address (HERE+2)
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BCF
Bit Clear f
Syntax:
[ label ] BCF
Operands:
0 f 255
0b7
a [0,1]
f,b[,a]
BN
Branch if Negative
Syntax:
[ label ] BN
Operands:
-128 n 127
Operation:
if negative bit is ‘1’
(PC) + 2 + 2n PC
None
Operation:
0 f
Status Affected:
Status Affected:
None
Encoding:
Encoding:
1001
Description:
ffff
ffff
1110
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
BCF
Before Instruction
FLAG_REG = 0xC7
After Instruction
FLAG_REG = 0x47
FLAG_REG,
0110
nnnn
nnnn
If the Negative bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Bit ‘b’ in register ‘f’ is cleared. If ‘a’
is ‘0’, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words:
Decode
bbba
n
Words:
1
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
7, 0
If No Jump:
Q1
Decode
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
Example:
HERE
BN
Jump
Before Instruction
PC
=
address (HERE)
After Instruction
If Negative
PC
If Negative
PC
DS30491D-page 374
=
=
=
=
1;
address (Jump)
0;
address (HERE+2)
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BNC
Branch if Not Carry
Branch if Not Negative
Syntax:
[ label ] BNC
Syntax:
[ label ] BNN
Operands:
-128 n 127
Operands:
-128 n 127
Operation:
if carry bit is ‘0’
(PC) + 2 + 2n PC
Operation:
if negative bit is ‘0’
(PC) + 2 + 2n PC
Status Affected:
None
Status Affected:
None
Encoding:
1110
Description:
n
BNN
0011
nnnn
nnnn
Encoding:
1110
If the Carry bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Description:
Words:
1
Words:
1
Cycles:
1(2)
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
n
0111
nnnn
nnnn
If the Negative bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
Decode
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
If No Jump:
Q1
Decode
Example:
HERE
BNC
Jump
Before Instruction
PC
=
=
=
=
=
Decode
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
Example:
HERE
BNN
Jump
Before Instruction
address (HERE)
After Instruction
If Carry
PC
If Carry
PC
If No Jump:
Q1
PC
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE+2)
After Instruction
0;
address (Jump)
1;
address (HERE+2)
2003-2013 Microchip Technology Inc.
If Negative
PC
If Negative
PC
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BNOV
Branch if Not Overflow
Branch if Not Zero
Syntax:
[ label ] BNOV
Syntax:
[ label ] BNZ
Operands:
-128 n 127
Operands:
-128 n 127
Operation:
if overflow bit is ‘0’
(PC) + 2 + 2n PC
Operation:
if zero bit is ‘0’
(PC) + 2 + 2n PC
Status Affected:
None
Status Affected:
None
Encoding:
1110
Description:
n
BNZ
0101
nnnn
nnnn
Encoding:
1110
If the Overflow bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Description:
Words:
1
Words:
1
Cycles:
1(2)
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
n
0001
nnnn
nnnn
If the Zero bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to PC
Decode
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
If No Jump:
Q1
Decode
Example:
HERE
BNOV Jump
Before Instruction
PC
=
DS30491D-page 376
Decode
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
Example:
HERE
BNZ
Jump
Before Instruction
address (HERE)
After Instruction
If Overflow
PC
If Overflow
PC
If No Jump:
Q1
PC
=
address (HERE)
After Instruction
=
=
=
=
0;
address (Jump)
1;
address (HERE+2)
If Zero
PC
If Zero
PC
=
=
=
=
0;
address (Jump)
1;
address (HERE+2)
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BRA
Unconditional Branch
Syntax:
[ label ] BRA
Operands:
-1024 n 1023
n
Operation:
(PC) + 2 + 2n PC
Status Affected:
None
Encoding:
1101
Description:
1
Cycles:
2
Q Cycle Activity:
Q1
No
operation
nnnn
nnnn
Add the 2’s complement number
‘2n’ to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is a
two-cycle instruction.
Words:
Decode
0nnn
Q2
Q3
Q4
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
BSF
Bit Set f
Syntax:
[ label ] BSF
Operands:
0 f 255
0b7
a [0,1]
Operation:
1 f
Status Affected:
None
Encoding:
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
HERE
BRA
Jump
PC
=
address (HERE)
After Instruction
PC
=
ffff
ffff
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
BSF
FLAG_REG, 7, 1
Before Instruction
FLAG_REG
Before Instruction
bbba
Bit ‘b’ in register ‘f’ is set. If ‘a’ is ‘0’,
Access Bank will be selected, overriding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value.
Words:
Example:
Example:
1000
f,b[,a]
=
0x0A
=
0x8A
After Instruction
FLAG_REG
address (Jump)
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BTFSC
Bit Test File, Skip if Clear
BTFSS
Bit Test File, Skip if Set
Syntax:
[ label ] BTFSC f,b[,a]
Syntax:
[ label ] BTFSS f,b[,a]
Operands:
0 f 255
0b7
a [0,1]
Operands:
0 f 255
0b (W)
(unsigned comparison)
Operation:
(f) –W),
skip if (f) < (W)
(unsigned comparison)
Status Affected:
None
Status Affected:
None
Encoding:
0110
Description:
010a
f [,a]
CPFSLT
ffff
ffff
Compares the contents of data
memory location ‘f’ to the contents
of the W by performing an
unsigned subtraction.
If the contents of ‘f’ are greater than
the contents of WREG, then the
fetched instruction is discarded and
a NOP is executed instead, making
this a two-cycle instruction. If ‘a’ is
‘0’, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Decode
Encoding:
Q2
Q3
Q4
Process
Data
No
operation
If skip:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
HERE
NGREATER
GREATER
CPFSGT REG, 0
:
:
After Instruction
If REG
PC
If REG
PC
=
=
W;
Address (GREATER)
W;
Address (NGREATER)
2003-2013 Microchip Technology Inc.
Q4
No
operation
Q1
No
operation
Address (HERE)
?
Q3
Process
Data
No
operation
No
operation
=
=
Q2
Read
register ‘f’
If skip:
No
operation
PC
W
ffff
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
No
operation
Before Instruction
ffff
Cycles:
No
operation
Example:
000a
Compares the contents of data
memory location ‘f’ to the contents
of W by performing an unsigned
subtraction.
If the contents of ‘f’ are less than
the contents of W, then the fetched
instruction is discarded and a NOP
is executed instead, making this a
two-cycle instruction. If ‘a’ is ‘0’, the
Access Bank will be selected. If ’a’
is ‘1’, the BSR will not be overridden (default).
Words:
Decode
Read
register ‘f’
0110
Description:
f [,a]
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NLESS
LESS
CPFSLT REG, 1
:
:
Before Instruction
PC
W
=
=
Address (HERE)
?
After Instruction
If REG
PC
If REG
PC
<
=
=
W;
Address (LESS)
W;
Address (NLESS)
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DAW
Decimal Adjust W Register
DECF
Decrement f
Syntax:
[ label ] DAW
Syntax:
[ label ] DECF f [,d [,a]]
Operands:
None
Operands:
Operation:
If [W >9] or [DC = 1] then
(W) + 6 W;
else
(W) W;
0 f 255
d [0,1]
a [0,1]
If [W >9] or [C = 1] then
(W) + 6 W;
else
(W) W;
Status Affected:
(f) – 1 dest
Status Affected:
C, DC, N, OV, Z
Encoding:
0000
Description:
0000
Description:
0000
0000
0111
DAW adjusts the eight-bit value in
W, resulting from the earlier
addition of two variables (each in
packed BCD format) and produces
a correct packed BCD result.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q3
Q4
Process
Data
Write
W
DAW
Before Instruction
=
=
=
1
Cycles:
1
Decode
Q2
Example1:
Words:
Q Cycle Activity:
Q1
Read
register W
0xA5
0
0
01da
ffff
ffff
Decrement register ‘f’. If ‘d’ is ‘0’,
the result is stored in W. If ‘d’ is ‘1’,
the result is stored back in register
‘f’ (default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
C
Encoding:
W
C
DC
Operation:
Example:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
DECF
CNT,
1, 0
Before Instruction
CNT
Z
=
=
0x01
0
After Instruction
CNT
Z
=
=
0x00
1
After Instruction
W
C
DC
=
=
=
0x05
1
0
Example 2:
Before Instruction
W
C
DC
=
=
=
0xCE
0
0
After Instruction
W
C
DC
=
=
=
DS30491D-page 384
0x34
1
0
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PIC18F6585/8585/6680/8680
DECFSZ
Decrement f, skip if 0
DCFSNZ
Decrement f, skip if not 0
Syntax:
[ label ] DECFSZ f [,d [,a]]
Syntax:
[ label ] DCFSNZ
Operands:
0 f 255
d [0,1]
a [0,1]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(f) – 1 dest,
skip if result = 0
Operation:
(f) – 1 dest,
skip if result 0
Status Affected:
None
Status Affected:
None
Encoding:
0010
Description:
11da
ffff
ffff
Encoding:
0100
11da
f [,d [,a]]
ffff
ffff
The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’
(default).
If the result is ‘0’, the next
instruction which is already fetched
is discarded and a NOP is executed
instead, making it a two-cycle
instruction. If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Description:
Words:
1
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’
(default).
If the result is not ‘0’, the next
instruction which is already fetched
is discarded and a NOP is executed
instead, making it a two-cycle
instruction. If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Q Cycle Activity:
Q1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Decode
If skip:
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
If skip:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
DECFSZ
GOTO
CNT, 1, 1
LOOP
Example:
HERE
Example:
CONTINUE
Before Instruction
PC
=
=
=
=
=
DCFSNZ
:
:
TEMP, 1, 0
Before Instruction
Address (HERE)
After Instruction
CNT
If CNT
PC
If CNT
PC
HERE
ZERO
NZERO
TEMP
=
?
=
=
=
=
TEMP - 1,
0;
Address (ZERO)
0;
Address (NZERO)
After Instruction
CNT - 1
0;
Address (CONTINUE)
0;
Address (HERE+2)
2003-2013 Microchip Technology Inc.
TEMP
If TEMP
PC
If TEMP
PC
DS30491D-page 385
18F8680.book Page 386 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
GOTO
Unconditional Branch
Syntax:
[ label ]
Operands:
0 k 1048575
Operation:
k PC
Status Affected:
None
Encoding:
1st word (k)
2nd word(k)
Description:
1110
1111
GOTO k
1111
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
GOTO allows an unconditional
branch anywhere within entire
2-Mbyte memory range. The 20-bit
value ‘k’ is loaded into PC.
GOTO is always a two-cycle
instruction.
Words:
2
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal
‘k’,
No
operation
Read literal
‘k’,
Write to PC
No
operation
No
operation
No
operation
No
operation
Example:
GOTO THERE
After Instruction
PC =
Address (THERE)
INCF
Increment f
Syntax:
[ label ]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(f) + 1 dest
Status Affected:
C, DC, N, OV, Z
Encoding:
0010
Description:
f [,d [,a]]
10da
ffff
ffff
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’
(default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
INCF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
INCF
CNT, 1, 0
Before Instruction
CNT
Z
C
DC
=
=
=
=
0xFF
0
?
?
After Instruction
CNT
Z
C
DC
DS30491D-page 386
=
=
=
=
0x00
1
1
1
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
INCFSZ
Increment f, skip if 0
Syntax:
[ label ]
Syntax:
[ label ]
0 f 255
d [0,1]
a [0,1]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(f) + 1 dest,
skip if result = 0
Operation:
(f) + 1 dest,
skip if result 0
Status Affected:
None
Status Affected:
None
0011
Description:
11da
f [,d [,a]]
Increment f, skip if not 0
Operands:
Encoding:
INCFSZ
INFSNZ
ffff
ffff
Encoding:
0100
INFSNZ
10da
f [,d [,a]]
ffff
ffff
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’
(default).
If the result is ‘0’, the next instruction which is already fetched is
discarded and a NOP is executed
instead, making it a two-cycle
instruction. If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Description:
Words:
1
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’
(default).
If the result is not ‘0’, the next
instruction which is already fetched
is discarded and a NOP is executed
instead, making it a two-cycle
instruction. If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Q Cycle Activity:
Q1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Decode
If skip:
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
If skip:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NZERO
ZERO
INCFSZ
:
:
Before Instruction
PC
=
=
=
=
=
Example:
HERE
ZERO
NZERO
INFSNZ
REG, 1, 0
Before Instruction
Address (HERE)
After Instruction
CNT
If CNT
PC
If CNT
PC
CNT, 1, 0
PC
=
Address (HERE)
After Instruction
CNT + 1
0;
Address (ZERO)
0;
Address (NZERO)
2003-2013 Microchip Technology Inc.
REG
If REG
PC
If REG
PC
=
=
=
=
REG + 1
0;
Address (NZERO)
0;
Address (ZERO)
DS30491D-page 387
18F8680.book Page 388 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
IORLW
Inclusive OR literal with W
Syntax:
[ label ]
Operands:
0 k 255
Operation:
(W) .OR. k W
Status Affected:
N, Z
Encoding:
0000
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
kkkk
kkkk
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
IORLW
Before Instruction
=
0x9A
After Instruction
W
1001
The contents of W are OR’ed with
the eight-bit literal ‘k’. The result is
placed in W.
Words:
W
IORLW k
=
0x35
IORWF
Inclusive OR W with f
Syntax:
[ label ]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(W) .OR. (f) dest
Status Affected:
N, Z
Encoding:
0001
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
0xBF
00da
f [,d [,a]]
ffff
ffff
Inclusive OR W with register ‘f’. If
‘d’ is ‘0’, the result is placed in W. If
‘d’ is ‘1’, the result is placed back in
register ‘f’ (default). If ‘a’ is ‘0’, the
Access Bank will be selected,
overriding the BSR value. If ‘a’ = 1,
then the bank will be selected as
per the BSR value (default).
Words:
Decode
IORWF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
IORWF
RESULT, 0, 1
Example:
Before Instruction
RESULT =
W
=
0x13
0x91
After Instruction
RESULT =
W
=
DS30491D-page 388
0x13
0x93
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
LFSR
Load FSR
Syntax:
[ label ]
Operands:
0f2
0 k 4095
Operation:
k FSRf
Status Affected:
None
Encoding:
Description:
1110
1111
LFSR f,k
1110
0000
00ff
k7kkk
k11kkk
kkkk
The 12-bit literal ‘k’ is loaded into
the file select register pointed to
by ‘f’.
Words:
2
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal
‘k’ MSB
Process
Data
Write
literal ‘k’
MSB to
FSRfH
Decode
Read literal
‘k’ LSB
Process
Data
Write literal
‘k’ to FSRfL
Example:
LFSR 2, 0x3AB
After Instruction
FSR2H
FSR2L
=
=
0x03
0xAB
MOVF
Move f
Syntax:
[ label ]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
f dest
Status Affected:
N, Z
Encoding:
0101
Description:
f [,d [,a]]
00da
ffff
ffff
The contents of register ‘f’ are
moved to a destination dependent
upon the status of ‘d’. If ‘d’ is ‘0’, the
result is placed in W. If ‘d’ is ‘1’, the
result is placed back in register ‘f’
(default). Location ‘f’ can be anywhere in the 256-byte bank. If ‘a’ is
‘0’, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
MOVF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write W
Example:
MOVF
REG, 0, 0
Before Instruction
REG
W
=
=
0x22
0xFF
After Instruction
REG
W
2003-2013 Microchip Technology Inc.
=
=
0x22
0x22
DS30491D-page 389
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PIC18F6585/8585/6680/8680
MOVFF
Move f to f
MOVLB
Move literal to low nibble in BSR
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 fs 4095
0 fd 4095
Operands:
0 k 255
Operation:
k BSR
Operation:
(fs) fd
Status Affected:
None
Status Affected:
None
Encoding:
Encoding:
1st word (source)
2nd word (destin.)
1100
1111
Description:
MOVFF fs,fd
ffff
ffff
ffff
ffff
ffffs
ffffd
The contents of source register ‘fs’
are moved to destination register
‘fd’. Location of source ‘fs’ can be
anywhere in the 4096-byte data
space (000h to FFFh) and location
of destination ‘fd’ can also be
anywhere from 000h to FFFh.
Either source or destination can be
W (a useful special situation).
MOVFF is particularly useful for
transferring a data memory location
to a peripheral register (such as the
transmit buffer or an I/O port).
The MOVFF instruction cannot use
the PCL, TOSU, TOSH or TOSL as
the destination register
Words:
2
Cycles:
2 (3)
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
(src)
Process
Data
No
operation
Decode
No
operation
No
operation
Write
register ‘f’
(dest)
No dummy
read
Example:
MOVFF
Description:
0000
1
Cycles:
1
Q Cycle Activity:
Q1
Example:
0001
kkkk
kkkk
The 8-bit literal ‘k’ is loaded into
the Bank Select Register (BSR).
Words:
Decode
MOVLB k
Q2
Q3
Q4
Read literal
‘k’
Process
Data
Write
literal ‘k’ to
BSR
MOVLB
5
Before Instruction
BSR register
=
0x02
=
0x05
After Instruction
BSR register
REG1, REG2
Before Instruction
REG1
REG2
=
=
0x33
0x11
After Instruction
REG1
REG2
=
=
DS30491D-page 390
0x33,
0x33
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
MOVLW
Move literal to W
Syntax:
[ label ]
Operands:
0 k 255
Operation:
kW
Status Affected:
None
Encoding:
0000
Description:
MOVLW k
1110
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
kkkk
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
MOVLW
0x5A
After Instruction
W
kkkk
The eight-bit literal ‘k’ is loaded into
W.
=
0x5A
MOVWF
Move W to f
Syntax:
[ label ]
Operands:
0 f 255
a [0,1]
Operation:
(W) f
Status Affected:
None
Encoding:
0110
Description:
111a
f [,a]
ffff
ffff
Move data from W to register ‘f’.
Location ‘f’ can be anywhere in the
256-byte bank. If ‘a’ is ‘0’, the
Access Bank will be selected, overriding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
MOVWF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
MOVWF
REG, 0
Before Instruction
W
REG
=
=
0x4F
0xFF
After Instruction
W
REG
2003-2013 Microchip Technology Inc.
=
=
0x4F
0x4F
DS30491D-page 391
18F8680.book Page 392 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
MULLW
Multiply Literal with W
MULWF
Multiply W with f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 k 255
Operands:
0 f 255
a [0,1]
Operation:
(W) x (f) PRODH:PRODL
Status Affected:
None
MULLW
k
Operation:
(W) x k PRODH:PRODL
Status Affected:
None
Encoding:
Description:
0000
1
Cycles:
1
Q Cycle Activity:
Q1
Example:
kkkk
kkkk
An unsigned multiplication is
carried out between the contents
of W and the 8-bit literal ‘k’. The
16-bit result is placed in
PRODH:PRODL register pair.
PRODH contains the high byte.
W is unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this
operation. A zero result is
possible but not detected.
Words:
Decode
1101
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write
registers
PRODH:
PRODL
MULLW
0xC4
Before Instruction
W
PRODH
PRODL
=
=
=
0xE2
?
?
=
=
=
0xE2
0xAD
0x08
Encoding:
Description:’
0000
001a
1
Cycles:
1
Q Cycle Activity:
Q1
Example:
ffff
ffff
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
registers
PRODH:
PRODL
After Instruction
W
PRODH
PRODL
f [,a]
An unsigned multiplication is
carried out between the contents
of W and the register file location
‘f’. The 16-bit result is stored in
the PRODH:PRODL register
pair. PRODH contains the high
byte.
Both W and ‘f’ are unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this
operation. A zero result is
possible but not detected. If ‘a’ is
‘0’, the Access Bank will be
selected, overriding the BSR
value. If ‘a’ = 1, then the bank
will be selected as per the BSR
value (default).
Words:
Decode
MULWF
MULWF
REG, 1
Before Instruction
W
REG
PRODH
PRODL
=
=
=
=
0xC4
0xB5
?
?
=
=
=
=
0xC4
0xB5
0x8A
0x94
After Instruction
W
REG
PRODH
PRODL
DS30491D-page 392
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
NEGF
Negate f
Syntax:
[ label ]
0 f 255
a [0,1]
Operation:
(f)+1f
Status Affected:
N, OV, C, DC, Z
Encoding:
0110
Description:
ffff
1
Cycles:
1
Q Cycle Activity:
Q1
[ label ]
None
Operation:
No operation
Status Affected:
None
0000
1111
Description:
1
Cycles:
1
Decode
0000
xxxx
0000
xxxx
0000
xxxx
No operation.
Words:
Q Cycle Activity:
Q1
NOP
Q2
Q3
Q4
No
operation
No
operation
No
operation
Example:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
Syntax:
Operands:
ffff
Location ‘f’ is negated using two’s
complement. The result is placed in
the data memory location ‘f’. If ‘a’ is
‘0’, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value.
Words:
Decode
110a
f [,a]
No Operation
Operands:
Encoding:
NEGF
NOP
NEGF
None.
REG, 1
Before Instruction
REG
=
0011 1010 [0x3A]
After Instruction
REG
=
1100 0110 [0xC6]
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
POP
Pop Top of Return Stack
Push Top of Return Stack
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
None
Operation:
(TOS) bit bucket
Operation:
(PC+2) TOS
Status Affected:
None
Status Affected:
None
Encoding:
0000
Description:
0000
0000
0110
The TOS value is pulled off the
return stack and is discarded. The
TOS value then becomes the
previous value that was pushed
onto the return stack.
This instruction is provided to
enable the user to properly manage
the return stack to incorporate a
software stack.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
POP
PUSH
Encoding:
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
No
operation
POP TOS
value
No
operation
Example:
Example:
POP
GOTO
NEW
Before Instruction
TOS
=
Stack (1 level down)=
0031A2h
014332h
After Instruction
TOS
PC
DS30491D-page 394
0000
=
=
014332h
NEW
0000
0000
0101
The PC+2 is pushed onto the top of
the return stack. The previous TOS
value is pushed down on the stack.
This instruction allows implementing a software stack by modifying
TOS, and then pushing it onto the
return stack.
Words:
Decode
PUSH
Q2
Q3
Q4
PUSH PC+2
onto return
stack
No
operation
No
operation
PUSH
Before Instruction
TOS
PC
=
=
00345Ah
000124h
PC
=
TOS
=
Stack (1 level down)=
000126h
000126h
00345Ah
After Instruction
2003-2013 Microchip Technology Inc.
18F8680.book Page 395 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
RCALL
Relative Call
Reset
Syntax:
[ label ] RCALL
Syntax:
[ label ]
Operands:
-1024 n 1023
Operands:
None
Operation:
(PC) + 2 TOS,
(PC) + 2 + 2n PC
Operation:
Reset all registers and flags that
are affected by a MCLR Reset.
Status Affected:
None
Status Affected:
All
Encoding:
Description:
1101
nnnn
nnnn
Subroutine call with a jump up to
1K from the current location. First,
return address (PC+2) is pushed
onto the stack. Then, add the 2’s
complement number ‘2n’ to the PC.
Since the PC will have incremented
to fetch the next instruction, the
new address will be PC+2+2n. This
instruction is a two-cycle
instruction.
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Decode
1nnn
n
RESET
Encoding:
Description:
0000
0000
1111
1111
This instruction provides a way to
execute a MCLR Reset in software.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
RESET
Q2
Q3
Q4
Start
Reset
No
operation
No
operation
RESET
After Instruction
Q2
Q3
Q4
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
Registers =
Flags*
=
Reset Value
Reset Value
Push PC to
stack
No
operation
Example:
No
operation
HERE
RCALL Jump
Before Instruction
PC =
Address (HERE)
After Instruction
PC =
TOS =
Address (Jump)
Address (HERE+2)
2003-2013 Microchip Technology Inc.
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RETFIE
Return from Interrupt
Return Literal to W
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
s [0,1]
Operands:
0 k 255
Operation:
(TOS) PC,
1 GIE/GIEH or PEIE/GIEL,
if s = 1
(WS) W,
(STATUSS) STATUS,
(BSRS) BSR,
PCLATU, PCLATH are unchanged.
Operation:
k W,
(TOS) PC,
PCLATU, PCLATH are unchanged
Status Affected:
None
Status Affected:
0000
Description:
0000
0001
0000
Description:
1
Cycles:
2
Q Cycle Activity:
Q1
1100
kkkk
kkkk
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Pop PC from
stack, Write
to W
No
operation
No
operation
No
operation
No
operation
Example:
Q2
Q3
Q4
No
operation
No
operation
Pop PC from
stack
Set GIEH or
GIEL
No
operation
Example:
RETLW k
W is loaded with the eight-bit literal
‘k’. The program counter is loaded
from the top of the stack (the return
address). The high address latch
(PCLATH) remains unchanged.
000s
Return from interrupt. Stack is
popped and Top-of-Stack (TOS) is
loaded into the PC. Interrupts are
enabled by setting either the high
or low priority global interrupt
enable bit. If ‘s’ = 1, the contents of
the shadow registers WS,
STATUSS and BSRS are loaded
into their corresponding registers,
W, Status and BSR. If ‘s’ = 0, no
update of these registers occurs
(default).
Words:
No
operation
Encoding:
GIE/GIEH, PEIE/GIEL.
Encoding:
Decode
RETFIE [s]
RETLW
RETFIE
No
operation
No
operation
1
CALL TABLE ;
;
;
;
:
TABLE
ADDWF PCL ;
RETLW k0
;
RETLW k1
;
:
:
RETLW kn
;
W contains table
offset value
W now has
table value
W = offset
Begin table
End of table
After Interrupt
PC
W
BSR
STATUS
GIE/GIEH, PEIE/GIEL
DS30491D-page 396
=
=
=
=
=
TOS
WS
BSRS
STATUSS
1
Before Instruction
W
=
0x07
After Instruction
W
=
value of kn
2003-2013 Microchip Technology Inc.
18F8680.book Page 397 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
RETURN
Return from Subroutine
RLCF
Rotate Left f through Carry
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
s [0,1]
Operands:
Operation:
(TOS) PC,
if s = 1
(WS) W,
(STATUSS) STATUS,
(BSRS) BSR,
PCLATU, PCLATH are unchanged
0 f 255
d [0,1]
a [0,1]
Operation:
(f) dest,
(f) C,
(C) dest
Status Affected:
C, N, Z
None
Encoding:
Status Affected:
Encoding:
0000
RETURN [s]
0000
0001
001s
Description:
Return from subroutine. The stack
is popped and the top of the stack
(TOS) is loaded into the program
counter. If ‘s’ = 1, the contents of
the shadow registers WS,
STATUSS and BSRS are loaded
into their corresponding registers,
W, Status and BSR. If ‘s’ = 0, no
update of these registers occurs
(default).
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Decode
No
operation
Q2
Q3
Q4
No
operation
Process
Data
Pop PC
from stack
No
operation
No
operation
No
operation
0011
Description:
01da
ffff
ffff
register f
C
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
f [,d [,a]]
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 W. If ‘d’ is ‘1’, the result
is stored back in register ‘f’
(default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
RLCF
REG, 0, 0
Before Instruction
Example:
RETURN
After Interrupt
PC =
RLCF
TOS
REG
C
1110 0110
0
After Instruction
REG
W
C
2003-2013 Microchip Technology Inc.
=
=
=
=
=
1110 0110
1100 1100
1
DS30491D-page 397
18F8680.book Page 398 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
RLNCF
Rotate Left f (no carry)
Syntax:
[ label ]
Syntax:
[ label ]
0 f 255
d [0,1]
a [0,1]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(f) dest,
(f) dest
Operation:
Status Affected:
N, Z
(f) dest,
(f) C,
(C) dest
Status Affected:
C, N, Z
0100
Description:
01da
f [,d [,a]]
Rotate Right f through Carry
Operands:
Encoding:
RLNCF
RRCF
ffff
ffff
The contents of register ‘f’ are
rotated one bit to the left. If ‘d’ is ‘0,’
the result is placed in W. If ‘d’ is ‘1’,
the result is stored back in register
‘f’ (default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
Encoding:
0011
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Process
Data
Write to
destination
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
RLNCF
REG, 1, 0
ffff
ffff
register f
C
Read
register ‘f’
Example:
00da
f [,d [,a]]
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 W. If ‘d’ is ‘1’, the result
is placed back in register ‘f’
(default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
register f
Words:
RRCF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Before Instruction
REG
=
1010 1011
After Instruction
REG
=
Example:
RRCF
REG, 0, 0
Before Instruction
0101 0111
REG
C
=
=
1110 0110
0
After Instruction
REG
W
C
DS30491D-page 398
=
=
=
1110 0110
0111 0011
0
2003-2013 Microchip Technology Inc.
18F8680.book Page 399 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
RRNCF
Rotate Right f (no carry)
Syntax:
[ label ]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(f) dest,
(f) dest
Status Affected:
N, Z
Encoding:
0100
Description:’
RRNCF
f [,d [,a]]
1
1
[ label ] SETF
0 f 255
a [0,1]
Operation:
FFh f
Status Affected:
None
0110
00da
ffff
100a
ffff
ffff
The contents of the specified
register are set to FFh. If ‘a’ is ‘0’,
the Access Bank will be selected,
overriding the BSR value. If ‘a’ is
‘1’, then the bank will be selected
as per the BSR value (default).
ffff
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
f [,a]
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
SETF
REG,1
Before Instruction
Q Cycle Activity:
Q1
Decode
Syntax:
Operands:
Description:
register f
Cycles:
Set f
Encoding:
The contents of register ‘f’ are
rotated one bit to the right. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is
‘1’, the result is placed back in
register ‘f’ (default). If ‘a’ is ‘0’, the
Access Bank will be selected,
overriding the BSR value. If ‘a’ is
‘1’, then the bank will be selected
as per the BSR value (default).
Words:
SETF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example 1:
RRNCF
REG
=
0x5A
After Instruction
REG
=
0xFF
REG, 1, 0
Before Instruction
REG
=
1101 0111
After Instruction
REG
=
Example 2:
1110 1011
RRNCF
REG, 0, 0
Before Instruction
W
REG
=
=
?
1101 0111
After Instruction
W
REG
=
=
1110 1011
1101 0111
2003-2013 Microchip Technology Inc.
DS30491D-page 399
18F8680.book Page 400 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
SLEEP
Enter Sleep mode
SUBFWP
Subtract f from W with borrow
Syntax:
[ label ] SLEEP
Syntax:
[ label ] SUBFWB
Operands:
None
Operands:
Operation:
00h WDT,
0 WDT postscaler,
1 TO,
0 PD
0 f 255
d [0,1]
a [0,1]
Status Affected:
TO, PD
Encoding:
0000
Description:
(W) – (f) – (C) dest
Status Affected:
N, OV, C, DC, Z
0000
0011
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
No
operation
Process
Data
Go to
SLEEP
Example:
SLEEP
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
?
?
After Instruction
TO =
PD =
1†
0
† If WDT causes wake-up, this bit is cleared.
01da
ffff
ffff
Subtract register ‘f’ and carry flag
(borrow) from W (2’s complement
method). If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored in register ‘f’ (default). If ‘a’
is ‘0’, the Access Bank will be
selected, overriding the BSR
value. If ‘a’ is ‘1’, then the bank will
be selected as per the BSR value
(default).
Words:
Before Instruction
TO =
PD =
0101
Description:
The Power-down status bit (PD) is
cleared. The Time-out status bit
(TO) is set. Watchdog Timer and
its postscaler are cleared.
The processor is put into Sleep
mode with the oscillator stopped.
Words:
Decode
Operation:
Encoding:
0000
f [,d [,a]]
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example 1:
SUBFWB
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
3
2
1
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 2:
FF
2
0
0
1 ; result is negative
SUBFWB
REG, 0, 0
Before Instruction
REG
W
C
=
=
=
2
5
1
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 3:
2
3
1
0
0
; result is positive
SUBFWB
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
1
2
0
After Instruction
REG
W
C
Z
N
DS30491D-page 400
=
=
=
=
=
0
2
1
1
0
; result is zero
2003-2013 Microchip Technology Inc.
18F8680.book Page 401 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
SUBLW
Subtract W from literal
SUBWF
Syntax:
[ label ] SUBLW k
Syntax:
[ label ] SUBWF
Operands:
0 k 255
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
k – (W) W
Status Affected:
N, OV, C, DC, Z
Encoding:
0000
Description:
1000
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example 1:
SUBLW
0x02
Before Instruction
=
=
1
?
=
=
=
=
1
1
0
0
Example 2:
; result is positive
SUBLW
0x02
=
=
=
=
=
=
0
1
1
0
Example 3:
; result is zero
SUBLW
=
=
=
=
=
=
0101
Description:
Words:
1
Cycles:
1
Decode
11da
ffff
ffff
Subtract W from register ‘f’ (2’s
complement method). If ‘d’ is ‘0’,
the result is stored in W. If ‘d’ is
‘1’, the result is stored back in
register ‘f’ (default). If ‘a’ is ‘0’, the
Access Bank will be selected,
overriding the BSR value. If ‘a’ is
‘1’, then the bank will be selected
as per the BSR value (default).
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
SUBWF
REG, 1, 0
Example 1:
=
=
=
3
2
?
REG
W
C
Z
N
=
=
=
=
=
1
2
1
0
0
; result is positive
SUBWF
REG, 0, 0
0x02
3
?
After Instruction
W
C
Z
N
Encoding:
After Instruction
Before Instruction
W
C
N, OV, C, DC, Z
REG
W
C
2
?
After Instruction
W
C
Z
N
(f) – (W) dest
Status Affected:
f [,d [,a]]
Before Instruction
Before Instruction
W
C
Operation:
Q Cycle Activity:
Q1
After Instruction
W
C
Z
N
kkkk
W is subtracted from the eight-bit
literal ‘k’. The result is placed in
W.
Words:
W
C
kkkk
Subtract W from f
FF ; (2’s complement)
0 ; result is negative
0
1
Example 2:
Before Instruction
REG
W
C
=
=
=
2
2
?
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 3:
2
0
1
1
0
SUBWF
; result is zero
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
1
2
?
After Instruction
REG
W
C
Z
N
2003-2013 Microchip Technology Inc.
=
=
=
=
=
FFh ;(2’s complement)
2
0
; result is negative
0
1
DS30491D-page 401
18F8680.book Page 402 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
SUBWFB
Subtract W from f with Borrow
SWAPF
Swap f
Syntax:
[ label ] SUBWFB
Syntax:
[ label ] SWAPF f [,d [,a]]
Operands:
0 f 255
d [0,1]
a [0,1]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(f) – (W) – (C) dest
Operation:
Status Affected:
N, OV, C, DC, Z
(f) dest,
(f) dest
Status Affected:
None
Encoding:
Description:
Words:
Cycles:
0101
ffff
ffff
Subtract W and the Carry flag (borrow) from register ‘f’ (2’s complement
method). If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’ (default). If
‘a’ is ‘0’, the Access Bank will be
selected, overriding the BSR value. If
‘a’ is ‘1’, then the bank will be
selected as per the BSR value
(default).
1
1
1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
SUBWFB
REG, 1, 0
=
=
=
0x19
0x0D
1
(0001 1001)
(0000 1101)
0x0C
0x0D
1
0
0
(0000 1011)
(0000 1101)
Example 2:
ffff
ffff
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
SWAPF
REG, 1, 0
Before Instruction
REG
=
0x53
After Instruction
After Instruction
=
=
=
=
=
Q Cycle Activity:
Q1
Decode
10da
The upper and lower nibbles of
register ‘f’ are exchanged. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is
‘1’, the result is placed in register ‘f’
(default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
Cycles:
Before Instruction
REG
W
C
Z
N
0011
Description:
Words:
Example 1:
REG
W
C
Encoding:
1
Q Cycle Activity:
Q1
Decode
10da
f [,d [,a]]
REG
=
0x35
; result is positive
SUBWFB REG, 0, 0
Before Instruction
REG
W
C
=
=
=
0x1B
0x1A
0
(0001 1011)
(0001 1010)
0x1B
0x00
1
1
0
(0001 1011)
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 3:
SUBWFB
; result is zero
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
0x03
0x0E
1
(0000 0011)
(0000 1101)
(1111 0100)
; [2’s comp]
(0000 1101)
After Instruction
REG
=
0xF5
W
C
Z
N
=
=
=
=
0x0E
0
0
1
DS30491D-page 402
; result is negative
2003-2013 Microchip Technology Inc.
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PIC18F6585/8585/6680/8680
TBLRD
Table Read
TBLRD
Table Read (Continued)
Example1:
TBLRD
Syntax:
[ label ]
Operands:
None
TBLRD ( *; *+; *-; +*)
Operation:
if TBLRD *,
(Prog Mem (TBLPTR)) TABLAT;
TBLPTR – No Change;
if TBLRD *+,
(Prog Mem (TBLPTR)) TABLAT;
(TBLPTR) + 1 TBLPTR;
if TBLRD *-,
(Prog Mem (TBLPTR)) TABLAT;
(TBLPTR) – 1 TBLPTR;
if TBLRD +*,
(TBLPTR) + 1 TBLPTR;
(Prog Mem (TBLPTR)) TABLAT;
Description:
0000
1
Cycles:
2
Q Cycle Activity:
Q1
No
operation
=
=
=
0x55
0x00A356
0x34
=
=
0x34
0x00A357
After Instruction
TABLAT
TBLPTR
Example2:
TBLRD
+* ;
Before Instruction
TABLAT
TBLPTR
MEMORY(0x01A357)
MEMORY(0x01A358)
=
=
=
=
0xAA
0x01A357
0x12
0x34
0000
0000
10nn
nn=0 *
=1 *+
=2 *=3 +*
TABLAT
TBLPTR
=
=
0x34
0x01A358
This instruction is used to read the
contents of Program Memory (P.M.). To
address the program memory, a pointer
called Table Pointer (TBLPTR) is used.
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2-Mbyte address
range.
TBLPTR[0] = 0: Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1: Most Significant
Byte of Program
Memory Word
The TBLRD instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words:
Decode
TABLAT
TBLPTR
MEMORY(0x00A356)
After Instruction
Status Affected:None
Encoding:
*+ ;
Before Instruction
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
No operation
operation
(Read
Program Memory)
2003-2013 Microchip Technology Inc.
No operation
(Write
TABLAT)
DS30491D-page 403
18F8680.book Page 404 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TBLWT
Table Write
TBLWT
Syntax:
[ label ] TBLWT ( *; *+; *-; +*)
Words: 1
Operands:
None
Cycles: 2
Operation:
if TBLWT*,
(TABLAT) Holding Register;
TBLPTR – No Change;
if TBLWT*+,
(TABLAT) Holding Register;
(TBLPTR) + 1 TBLPTR;
if TBLWT*-,
(TABLAT) Holding Register;
(TBLPTR) – 1 TBLPTR;
if TBLWT+*,
(TBLPTR) + 1 TBLPTR;
(TABLAT) Holding Register;
Q Cycle Activity:
Description:
0000
0000
0000
11nn
nn=0 *
=1 *+
=2 *=3 +*
This instruction uses the 3 LSBs of
TBLPTR to determine which of the
8 holding registers the TABLAT is
written to. The holding registers are
used to program the contents of
Program Memory (P.M.). (Refer
to Section 5.0 “Flash Program
Memory” for additional details on
programming Flash memory.)
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2-MBtye address
range. The LSb of the TBLPTR
selects which byte of the program
memory location to access.
TBLPTR[0] = 0:Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1:Most Significant
Byte of Program
Memory Word
The TBLWT instruction can modify
the value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
DS30491D-page 404
Q1
Q2
Q3
Q4
Decode
No
operation
No
operation
No
operation
No
operation
No
operation
(Read
TABLAT)
No
operation
No
operation
(Write to
Holding
Register )
Example1:
Status Affected: None
Encoding:
Table Write (Continued)
TBLWT
*+;
Before Instruction
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
=
=
0x55
0x00A356
=
0xFF
After Instructions (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
Example 2:
TBLWT
=
=
0x55
0x00A357
=
0x55
+*;
Before Instruction
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
=
=
0x34
0x01389A
=
0xFF
=
0xFF
After Instruction (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
=
=
0x34
0x01389B
=
0xFF
=
0x34
2003-2013 Microchip Technology Inc.
18F8680.book Page 405 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
TSTFSZ
Test f, skip if 0
XORLW
Exclusive OR literal with W
Syntax:
[ label ] TSTFSZ f [,a]
Syntax:
[ label ] XORLW k
Operands:
0 f 255
a [0,1]
Operands:
0 k 255
Operation:
skip if f = 0
Status Affected:
None
Encoding:
0110
Description:
ffff
ffff
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Decode
(W) .XOR. k W
Status Affected:
N, Z
Encoding:
011a
If ‘f’ = 0, the next instruction,
fetched during the current
instruction execution is discarded
and a NOP is executed, making this
a two-cycle instruction. If ‘a’ is ‘0’,
the Access Bank will be selected,
overriding the BSR value. If ‘a’ is
‘1’, then the bank will be selected
as per the BSR value (default).
Q Cycle Activity:
Q1
Operation:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
No
operation
0000
Description:
1010
kkkk
kkkk
The contents of W are XORed
with the 8-bit literal ‘k’. The result
is placed in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example:
XORLW 0xAF
Before Instruction
W
=
0xB5
After Instruction
W
=
0x1A
If skip:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NZERO
ZERO
TSTFSZ
:
:
CNT, 1
Before Instruction
PC
=
Address (HERE)
After Instruction
If CNT
PC
If CNT
PC
=
=
=
0x00,
Address (ZERO)
0x00,
Address (NZERO)
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XORWF
Exclusive OR W with f
Syntax:
[ label ] XORWF
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(W) .XOR. (f) dest
Status Affected:
N, Z
Encoding:
0001
Description:
ffff
ffff
Exclusive OR the contents of W
with register ‘f’. If ‘d’ is ‘0’, the result
is stored in W. If ‘d’ is ‘1’, the result
is stored back in the register ‘f’
(default). If ‘a’ is ‘0’, the Access
Bank will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
10da
f [,d [,a]]
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
XORWF
REG, 1, 0
Before Instruction
REG
W
=
=
0xAF
0xB5
After Instruction
REG
W
=
=
DS30491D-page 406
0x1A
0xB5
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26.0
DEVELOPMENT SUPPORT
The PIC® 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®
- PICDEM MSC
- microID®
- CAN
- PowerSmart®
- Analog
26.1
MPLAB Integrated Development
Environment Software
The MPLAB IDE software brings an ease of software
development previously unseen in the 8/16-bit microcontroller market. The MPLAB IDE is a Windows®
based application that contains:
• An interface to debugging tools
- simulator
- programmer (sold separately)
- emulator (sold separately)
- in-circuit debugger (sold separately)
• A full-featured editor with color coded context
• A multiple project manager
• Customizable data windows with direct edit of
contents
• High-level source code debugging
• Mouse over variable inspection
• Extensive on-line help
The MPLAB IDE allows you to:
• Edit your source files (either assembly or C)
• One touch assemble (or compile) and download
to PIC MCU 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.
26.2
MPASM Assembler
The MPASM assembler is a full-featured, universal
macro assembler for all PIC 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
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26.3
MPLAB C17 and MPLAB C18
C Compilers
The MPLAB C17 and MPLAB C18 Code Development
Systems are complete ANSI C compilers for
Microchip’s PIC17CXXX and PIC18CXXX family of
microcontrollers. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use not found with other compilers.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
26.4
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
26.5
MPLAB C30 C Compiler
The MPLAB C30 C compiler is a full-featured, ANSI
compliant, optimizing compiler that translates standard
ANSI C programs into dsPIC30F assembly language
source. The compiler also supports many 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 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.
DS30491D-page 408
26.6
MPLAB ASM30 Assembler, Linker
and Librarian
MPLAB ASM30 assembler produces relocatable
machine code from symbolic assembly language for
dsPIC30F devices. MPLAB C30 compiler uses the
assembler to produce it’s object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:
•
•
•
•
•
•
Support for the entire dsPIC30F instruction set
Support for fixed-point and floating-point data
Command line interface
Rich directive set
Flexible macro language
MPLAB IDE compatibility
26.7
MPLAB SIM Software Simulator
The MPLAB SIM software simulator allows code development in a PC hosted environment by simulating the
PIC 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.
26.8
MPLAB SIM30 Software Simulator
The MPLAB SIM30 software simulator allows code
development in a PC hosted environment by simulating
the dsPIC30F series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user defined key press, to any of the pins.
The MPLAB SIM30 simulator fully supports symbolic
debugging using the MPLAB C30 C Compiler and
MPLAB ASM30 assembler. The simulator runs in either
a Command Line mode for automated tasks, or from
MPLAB IDE. This high-speed simulator is designed to
debug, analyze and optimize time intensive DSP
routines.
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26.9
MPLAB ICE 2000
High-Performance Universal
In-Circuit Emulator
The MPLAB ICE 2000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for PIC
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 PIC 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.
26.10 MPLAB ICE 4000
High-Performance Universal
In-Circuit Emulator
The MPLAB ICE 4000 universal in-circuit emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for highend PIC 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.
2003-2013 Microchip Technology Inc.
26.11 MPLAB ICD 2 In-Circuit Debugger
Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a
powerful, low-cost, run-time development tool,
connecting to the host PC via an RS-232 or high-speed
USB interface. This tool is based on the Flash PIC
MCUs and can be used to develop for these and other
PIC microcontrollers. The MPLAB ICD 2 utilizes the incircuit 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, singlestepping 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 PIC devices.
26.12 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 PIC devices without a PC connection. It can
also set code protection in this mode.
26.13 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 StandAlone mode, the MPLAB PM3 device programmer can
read, verify and program PIC 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.
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26.14 PICSTART Plus Development
Programmer
26.17 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 PIC 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.
26.15 PICDEM 1 PIC MCU
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.
26.16 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
DS30491D-page 410
26.18 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.
26.19 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 onboard 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.
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26.20 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.
26.21 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.
26.22 PICDEM LIN PIC16C43X
Demonstration Board
The powerful LIN hardware and software kit includes a
series of boards and three PIC microcontrollers. The
small footprint PIC16C432 and PIC16C433 are used
as slaves in the LIN communication and feature onboard LIN transceivers. A PIC16F874 Flash
microcontroller serves as the master. All three microcontrollers are programmed with firmware to provide
LIN bus communication.
26.24 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.
26.25 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.
26.23 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.
2003-2013 Microchip Technology Inc.
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NOTES:
DS30491D-page 412
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27.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings (†)
Ambient temperature under bias.............................................................................................................-40°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on any pin with respect to VSS (except VDD, MCLR, and RA4) ......................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ......................................................................................................... -0.3V to +5.5V
Voltage on MCLR with respect to VSS (Note 2) ......................................................................................... 0V to +13.25V
Voltage on RA4 with respect to Vss ............................................................................................................... 0V to +8.5V
Total power dissipation (Note 1) ...............................................................................................................................1.0W
Maximum current out of VSS pin ...........................................................................................................................300 mA
Maximum current into VDD pin ..............................................................................................................................250 mA
Input clamp current, IIK (VI < 0 or VI > VDD) 20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) 20 mA
Maximum output current sunk by any I/O pin..........................................................................................................25 mA
Maximum output current sourced by any I/O pin ....................................................................................................25 mA
Maximum current sunk byall ports .......................................................................................................................200 mA
Maximum current sourced by all ports ..................................................................................................................200 mA
Note 1: Power dissipation is calculated as follows:
Pdis = VDD x {IDD – IOH} + {(VDD – VOH) x IOH} + (VOl x IOL)
2: Voltage spikes below VSS at the MCLR/VPP pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100 should be used when applying a “low” level to the MCLR/VPP pin rather
than pulling this pin directly to VSS.
† 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.
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FIGURE 27-1:
PIC18F6585/8585/6680/8680 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
5.0V
PIC18FXX8X
Voltage
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
Frequency
FMAX
FMAX = 40 MHz for PIC18F6X8X and PIC18F8X8X in Microcontroller mode.
FMAX = 25 MHz for PIC18F8X8X in modes other than Microcontroller mode.
FIGURE 27-2:
PIC18LF6585/8585/6680/8680 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
Voltage
5.0V
PIC18LFXX8X
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
FMAX
4 MHz
Frequency
For PIC18F6X8X and PIC18F8X8X in Microcontroller mode:
FMAX = (16.36 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz, if VDDAPPMIN 4.2V;
FMAX = 40 MHz, if VDDAPPMIN > 4.2V.
For PIC18F8X8X in modes other than Microcontroller mode:
FMAX = (9.55 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz, if VDDAPPMIN 4.2V;
FMAX = 25 MHz, if VDDAPPMIN > 4.2V.
Note: VDDAPPMIN is the minimum voltage of the PIC® device in the application.
DS30491D-page 414
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FIGURE 27-3:
PIC18F6585/8585/6680/8680 VOLTAGE-FREQUENCY GRAPH (EXTENDED)
6.0V
5.5V
Voltage
5.0V
PIC18FXX8X
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
25 MHz
Frequency
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PIC18F6585/8585/6680/8680
27.1
DC Characteristics: Supply Voltage
PIC18FXX8X (Industrial, Extended)
PIC18LFXX8X (Industrial)
PIC18LFXX8X
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18FXX8X
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param.
Symbol
No.
D001
VDD
Characteristic
Min
Typ
Max
Units
PIC18LFXX8X
2.0
—
5.5
V
PIC18FXX8X
4.2
—
5.5
V
VDD – 0.3
—
VDD + 0.3
V
Conditions
Supply Voltage
D001A AVDD
Analog Supply
Voltage
D002
VDR
RAM Data Retention
Voltage(1)
1.5
—
—
V
D003
VPOR
VDD Start Voltage
to ensure internal
Power-on Reset signal
—
—
0.7
V
D004
SVDD
VDD Rise Rate
to ensure internal
Power-on Reset signal
0.05
—
—
D005
VBOR
Brown-out Reset Voltage
HS, XT, RC and LP Oscillator mode
See section on Power-on Reset for
details
V/ms See section on Power-on Reset for
details
BORV1:BORV0 = 11
1.96
—
2.18
V
BORV1:BORV0 = 10
2.64
—
2.92
V
BORV1:BORV0 = 01
4.11
—
4.55
V
BORV1:BORV0 = 00
4.41
—
4.87
V
Legend: Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM
data.
DS30491D-page 416
2003-2013 Microchip Technology Inc.
18F8680.book Page 417 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
27.2
DC Characteristics:
Power-down and Supply Current
PIC18FXX8X (Industrial, Extended)
PIC18LFXX8X (Industrial)
PIC18LFXX8X
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18FXX8X
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param.
No.
Device
Typ
Max
Units
Conditions
Power-down Current (IPD)(1)
D020
D020A
D020B
PIC18LFXX8X
PIC18LFXX8X
All devices
0.2
1
A
-40°C
0.2
1
A
+25°C
+85°C
5.0
10
A
0.4
1
A
-40°C
0.4
1
A
+25°C
+85°C
3.0
18
A
0.7
2
A
-40°C
0.7
2
A
+25°C
15.0
32
A
+85°C
VDD = 2.0V,
(Sleep mode)
VDD = 3.0V,
(Sleep mode)
VDD = 5.0V,
(Sleep mode)
Legend: Shading of rows is to assist in readability of the table.
Note 1: 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 or VSS and
all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as
I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and
temperature, also have an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can
be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
2003-2013 Microchip Technology Inc.
DS30491D-page 417
18F8680.book Page 418 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
27.2
DC Characteristics:
Power-down and Supply Current
PIC18FXX8X (Industrial, Extended)
PIC18LFXX8X (Industrial) (Continued)
PIC18LFXX8X
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18FXX8X
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param.
No.
Device
Typ
Max
Units
Conditions
PIC18LFXX8X 500
500
A
-40°C
300
500
A
+25°C
850
1000
A
+85°C
PIC18LFXX8X 500
900
A
-40°C
500
900
A
+25°C
+85°C
Supply Current (IDD)(2,3)
D010
All devices
PIC18LFXX8X
PIC18LFXX8X
All devices
1
1.5
mA
1
2
mA
-40°C
1
2
mA
+25°C
1.3
3
mA
+85°C
1
2
mA
-40°C
1
2
mA
+25°C
1.5
2.5
mA
+85°C
1.5
2
mA
-40°C
1.5
2
mA
+25°C
+85°C
2
2.5
mA
3
5
mA
-40°C
3
5
mA
+25°C
4
6
mA
+85°C
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHZ,
EC oscillator
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 4 MHz,
EC oscillator
VDD = 5.0V
Legend: Shading of rows is to assist in readability of the table.
Note 1: 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 or VSS and
all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as
I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and
temperature, also have an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can
be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
DS30491D-page 418
2003-2013 Microchip Technology Inc.
18F8680.book Page 419 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
27.2
DC Characteristics:
Power-down and Supply Current
PIC18FXX8X (Industrial, Extended)
PIC18LFXX8X (Industrial) (Continued)
PIC18LFXX8X
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18FXX8X
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param.
No.
Device
Typ
Max
Units
Conditions
13
27
mA
-40°C
15
27
mA
+25°C
19
29
mA
+85°C
17
31
mA
-40°C
21
31
mA
+25°C
23
34
mA
+85°C
20
34
mA
-40°C
24
34
mA
+25°C
29
44
mA
+85°C
28
46
mA
-40°C
33
46
mA
+25°C
40
51
mA
+85°C
27
45
A
-10°C
30
50
A
+25°C
32
54
A
+70°C
33
55
A
-10°C
36
60
A
+25°C
+70°C
Supply Current (IDD)(2,3)
PIC18FXX8X
PIC18FXX8X
PIC18FXX8X
PIC18FXX8X
D014
PIC18LFXX8X
PIC18LFXX8X
All devices
39
65
A
75
125
A
-10°C
90
150
A
+25°C
113
188
A
+70°C
VDD = 4.2V
FOSC = 25 MHZ,
EC oscillator
VDD = 5.0V
VDD = 4.2V
FOSC = 40 MHZ,
EC oscillator
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 32 kHz,
Timer1 as clock
VDD = 5.0V
Legend: Shading of rows is to assist in readability of the table.
Note 1: 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 or VSS and
all features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as
I/O pin loading and switching rate, oscillator type and circuit, internal code execution pattern and
temperature, also have an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;
MCLR = VDD; WDT enabled/disabled as specified.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can
be estimated by the formula Ir = VDD/2REXT (mA) with REXT in k.
2003-2013 Microchip Technology Inc.
DS30491D-page 419
18F8680.book Page 420 Tuesday, January 29, 2013 1:32 PM
PIC18F6585/8585/6680/8680
27.2
DC Characteristics:
Power-down and Supply Current
PIC18FXX8X (Industrial, Extended)
PIC18LFXX8X (Industrial) (Continued)
PIC18LFXX8X
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18FXX8X
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param.
No.
Device
Typ
Max
Units
Conditions
Module Differential Currents (IWDT, IBOR, ILVD, IOSCB, IAD)
D022
(IWDT)
Watchdog Timer
D022A
(IBOR)
Brown-out Reset
D022B
(ILVD)
Low-Voltage Detect
D025
(IOSCB)
D026
(IAD)
Timer1 Oscillator
A/D Converter
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