LIST P=16F877
INCLUDE "P16F877.INC"
;----------------------------------------------
ORG 0000H
NOP
GOTO MAIN
;----------------------------------------------
;中断服务程序
ORG 0004H ;中断程序起始地址
MOVLW 83H
MOVWF TMR0
BCF INTCON,T0IF
DECFSZ 20H,1
RETFIE
CALL HD
MOVLW 7DH
MOVWF 20H
RETFIE
;----------------------------------------------
;主函数
ORG 0200H
MAIN BSF STATUS,RP0
CLRF TRISC
MOVLW 05H
MOVWF OPTION_REG
BCF STATUS,RP0
;----------------
;设置初始值
MOVLW 01H
MOVWF PORTC
MOVLW 83H
MOVWF TMR0
BSF INTCON,T0IE
BSF INTCON,GIE
MOVLW 7DH
MOVWF 20H
GOTO
;----------------------------------------------
;换灯
HD BTFSS PORTC,07H
GOTO JX
MOVLW 01H
MOVWF PORTC
RETURN
JX RLF PORTC,1
RETURN
END