8255交通燈 試驗《黃海萍版》微機實驗
2007年08月02日 星期四 17:46
   DATA   SEGMENT
          BUF   DB         81H,81H,81H,81H
               DB         41H,01H,41H,01H,41H,01H,41H,01H,41H
               DB         24H,24H,24H,24H
               DB         22H,20H,22H,20H,22H,20H,22H,20H,22H
               DB         00H
         DATA   ENDS
         CODE   SEGMENT
               ASSUME     CS:CODE,DS:DATA
       START:
               MOV        AX,DATA
               MOV        DS,AX
               MOV        AL,80H       ;;;;;;;;;;;當時片選接到288H~28FH的接口上
               MOV        DX,0C40BH
               OUT        DX,AL
               MOV        DX,0C40AH
          RE:
               MOV        BX,0
          ON:
               MOV        AL,BUF[BX]
               CMP        AL,00H
               JZ         RE
               INC        BX
               OUT        DX,AL
               MOV        CX,0FFFFH
               TEST       AL,42H
               JZ         DE1
               MOV        CX,0FFFH
         DE1:
               MOV        DI,02FFFH
         DE0:
               DEC        DI
               JNE        DE0
               MOV        AH,1
               INT        16H
               JNE        EXIT
               LOOP       DE1
               JMP        ON
        EXIT:
               MOV        AH,4CH
               INT        21H
         CODE   ENDS
               END        START