PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 187

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

EXAMPLE 17-1: WIN AND ICODE BITS USAGE IN INTERRUPT SERVICE ROUTINE TO ACCESS
WakeupInterrupt
NoInterrupt
ErrorInterrupt
TXB2Interrupt
TXB1Interrupt
TXB0Interrupt
RXB1Interrupt
2000 Microchip Technology Inc.
; 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
movff
movf
andlw
addwf
bra
bra
bra
bra
bra
bra
bra
bcf
;
; User code to handle wake-up procedure
;
;
; Continue checking for other interrupt source or return from here
…
…
bcf
…
retfie
bcf
goto
bcf
goto
bcf
goto
bcf
goto
CANCON, TempCANCON
CANSTAT, TempCANSTAT
TempCANSTAT, W
b’00001110’
PCL, F
NoInterrupt
ErrorInterrupt
TXB2Interrupt
TXB1Interrupt
TXB0Interrupt
RXB1Interrupt
RXB0Interrupt
PIR3, WAKIF
PIR3, ERRIF
PIR3, TXB2IF
AccessBuffer
PIR3, TXB1IF
AccessBuffer
PIR3, TXB0IF
AccessBuffer
PIR3, RXB1IF
Accessbuffer
TX/RX BUFFERS
Advanced Information
; Save CANCON.WIN bits
; This is required to prevent CANCON
; from corrupting CAN buffer access
; in-progress while this interrupt
; occurred
; Save CANSTAT register
; This is required to make sure that
; we use same CANSTAT value rather
; than one changed by another CAN
; interrupt.
; Retrieve ICODE bits
; Perform computed GOTO
; to corresponding interrupt cause
; 000 = No interrupt
; 001 = Error interrupt
; 010 = TXB2 interrupt
; 011 = TXB1 interrupt
; 100 = TXB0 interrupt
; 101 = RXB1 interrupt
; 110 = RXB0 interrupt
; 111 = Wake-up on interrupt
; Clear the interrupt flag
; PC should never vector here. User may
; place a trap such as infinite loop or pin/port
; indication to catch this error.
; Clear the interrupt flag
; Handle error.
; Clear the interrupt flag
; Clear the interrupt flag
; Clear the interrupt flag
; Clear the interrupt flag
PIC18CXX8
DS30475A-page 187