PIC16C71单片机按键换醒CPU源程序

; p=pic16c71,xt=40000hz
LIST P=16c71
;
Z            EQU    2
RBPU         EQU    7
TEMP         EQU    10H
OPTIONREG    EQU    1H
F            EQU    1
PORT_B       EQU    06H
;
             INCLUDE <P16c71.INC>
             LIST
;
             ORG     0                  ；复位地址
             GOTO    START
;
             ORG     4                  ；中断向量
             GOTO    SERVICEINTERRUPT
;
START
             CALL    INITPORT_B         ；初始化B口
LOOP
             SLEEP                      ；省电睡眠，等待被唤醒
             NOP
             GOTO    LOOP
;
SERVICEINTERRUPT
             BTFSC   INTCON,RBIF
             GOTO    SERVICEWAKUP
             CLRF    INTCON
             BSF     INTCON,RBIE
             RETFIE
;
;检查是哪个键被按下，并点亮相应的LED直到按键释放，再返回睡眠状态
;
SERVICEWAKUP
             BCF     INTCON,RBIE
             COMF    PORT_B,W
             BCF     INTCON,RBIF
             CALL    DELAY16
             COMF    PORT_B,W
             ANDLW   B'11110000'
             MOVWF   TEMP
             SWAPF   TEMP,W
             MOVWF   PORT_B
             CALL    KEYRELEASE
             RETFIE
;
;等待所有的按键都被释放程序
;
KEYRELEASE
             CALL    DELAY16
             COMF    PORT_B,W
             BCF     INTCON,RBIF
               BCF     INTCON,RBIE
             ANDLW   B'11110000'
             BTFSC   STATUS,Z
             RETURN
             GOTO    KEYRELEASE
;
;初始化    B口子程序
;
INITPORT_B
             BSF     STATUS,RP0
             MOVLW   B'11110000'
             MOVWF   TRISB
             BCF     OPTIONREG,RBPU
             BCF     STATUS,RP0
             CLRF    PORT_B
             BCF     INTCON,RBIE
             MOVF    PORT_B,W
             BCF     INTCON,RBIF
             BSF     INTCON,RBIE
             BSF     INTCON,GIE
             RETURN
;
;延时去抖动子程序
DELAY16
             BSF     STATUS,RP0
             MOVLW   B'00000111'
             MOVWF   OPTIONREG
             BCF     STATUS,RP0
             CLRF    TMR0
             BCF     INTCON,T0IF
CHECKAGAIN
             BTFSS   INTCON,T0IF
             GOTO    CHECKAGAIN
             BCF     INTCON,T0IF
             RETURN
             END