RB0－正轉按鈕  RB1－反轉按鈕 RB2－停止按鈕 RD0－電動機正轉 RD1－電動機反轉

程序：

INCLUDE”P16F877”.INC

              ORG           0000H

              NOP

              BSF            STATUS,RPO

              MOVLW       00H

              MOVWF       TRISD

              MOVLW       07H

              MOVWF       TRISB

              BCF            STATUS,RP0

              CLRF           PORTD

              ST              NOP

N1          BTFSS         PORTB,0

              GOTO          N3

              CALL           DELAY10MS

              BTFSS         PORTB,0

              GOTO          N3

N2          BTFSC         PORTD,1

              GOTO          N3

              BCF            PORTD,1

              BSF            PORTD,0

N3         BTFSS         PORTB,1

             GOTO          N5

             CALL           DELAY10MS

             BTFSS         PORTB,1

             GOTO          N5

N4         BTFSS         PORTD,0

             GOTO          N5

             BCF             PORTD,0

             BSF             PORTD,1

N5         BTFSS         PORTB,2

             GOTO          N1

             CALL           DELAY10MS

             BTFSS         PORTB,2

             GOTO          N1

             BCF             PORTD,0

             BCF             PORTD,1

             GOTO ST
DELAY10MS MOVLW  0DH

             MOVWF       20H

LOOP1    MOVLW       0FFH

             MOVWF       21H

LOOP2    DECFSZ      21H

             GOTO          LOOP2

             DECFSZ      20H

             GOTO         LOOP1

              RETURN

              END
;我是新手，寫的不好不要見笑