程序如下:
LIST P=18F248
INCLUDE "P18F248.INC"
CAN_FLAG EQU 0x20
ORG 0x0000
GOTO MAIN
ORG 0x0008
GOTO CAN_INTSERVE
ORG 0x30
INITIAL
MOVLW 0x08
MOVWF TRISB
MOVLW 0x80
MOVWF CANCON
WAIT
BTFSS CANSTAT,OPMODE2
GOTO WAIT
MOVLW 0x01
MOVWF BRGCON1
MOVLW 0x90
MOVWF BRGCON2
MOVLW 0x42
MOVWF BRGCON3
MOVLW 0x03
MOVWF TXB0CON ;???????为什么写不进去？？？
MOVLW 0xFF
MOVWF TXB0SIDH ;?????
MOVLW 0xE0
MOVWF TXB0SIDL ;?????
MOVLW 0x08
MOVWF TXB0DLC ;???
MOVLW 0x0F
MOVWF BSR
MOVLW 0x00
MOVWF TXB0D0
MOVLW 0x01
MOVWF TXB0D1
MOVLW 0x02
MOVWF TXB0D2
MOVLW 0x03
MOVWF TXB0D3
MOVLW 0x04
MOVWF TXB0D4
MOVLW 0x05
MOVWF TXB0D5
MOVLW 0x06
MOVWF TXB0D6
MOVLW 0x07
MOVWF TXB0D7
MOVLW 0xFF
MOVWF RXB0SIDH
MOVLW 0xE0
MOVWF RXB0SIDL
MOVLW 0x20
MOVWF RXB0CON
MOVLW 0x08
MOVWF RXB0DLC
MOVLW 0x00
MOVWF RXB0D0
MOVLW 0x00
MOVWF RXB0D1
MOVLW 0x00
MOVWF RXB0D2
MOVLW 0x00
MOVWF RXB0D3
MOVLW 0x00
MOVWF RXB0D4
MOVLW 0x00
MOVWF RXB0D5
MOVLW 0x00
MOVWF RXB0D6
MOVLW 0x00
MOVWF RXB0D7
MOVLW 0xFF
MOVWF RXF0SIDH
MOVLW 0xE0
MOVWF RXF0SIDL
MOVLW 0x00
MOVWF RXM0SIDH
MOVLW 0x00
MOVWF RXM0SIDL
MOVLW 0x00
MOVWF CIOCON
MOVLW 0x40
MOVWF CANCON
WAIT2
MOVF CANSTAT
ANDLW 0xE0
SUBLW 0x40
BTFSS STATUS,Z
GOTO WAIT2
MOVLW 0x00
MOVWF PIR3
MOVLW 0x01
MOVWF PIE3
MOVLW 0x01
MOVWF IPR3
RETURN
CAN_INTSERVE
WAIT3
BTFSS PIR3,RXB0IF
GOTO ERR_EXIT
BSF CAN_FLAG,0
BCF PIR3,RXB0IF
BCF RXB0CON,RXFUL
ERR_EXIT
RETFIE
MAIN NOP
CLRF INTCON
CALL INITIAL
MOVLW 0xC0
MOVWF INTCON
LOOP
BSF TXB0CON,TXREQ
WAITE4
BTFSS PIR3,TXB0IF
GOTO WAITE4
WAITE5
BTFSS CAN_FLAG,0
GOTO WAITE5
BCF CAN_FLAG,0
BCF TXB0CON,TXREQ
INCF RXB0D0,0
MOVWF TXB0D0
INCF RXB0D1,0
MOVWF TXB0D1
INCF RXB0D2,0
MOVWF TXB0D2
INCF RXB0D3,0
MOVWF TXB0D3
INCF RXB0D4,0
MOVWF TXB0D4
INCF RXB0D5,0
MOVWF TXB0D5
INCF RXB0D6,0
MOVWF TXB0D6
INCF RXB0D7,0
MOVWF TXB0D7
GOTO LOOP
RETURN
END
出现的问题如下:
TXB0CON
TXB0SIDH
TXB0SIDL
TXB0DLC
这四个寄存器一直是初始值,写不进新值,很困惑,不知各位遇到过这样的问题没有.. |
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