;8155   A口地址--7F01，B口地址--7F02，C口地址--7F03

       org 0h

       mov   a,#0fh
       mov   dptr,  #7F00H      ;控制口地址
       movx  @dptr,a
Loop:
       mov   a, #0FEh
       mov   r2, #8
Output:
       mov   dptr,#7F01H        ;A口地址
       movx  @dptr, a
       mov   dptr,#7F02H        ;B口地址
       movx  @dptr, a
       mov   dptr,#7F03H        ;C口地址
       movx  @dptr, a
       Acall  Delay
       rl    a
       djnz  r2, Output
       ljmp  Loop

Delay: mov   r5, #03
       mov   r6, #0FFH
       mov   r7, #0FFH
DelayLoop:
       djnz  r7, DelayLoop
       djnz  r6, DelayLoop
       djnz  r5, DelayLoop
       ret

       end