; 輸出 50% (5:5) 占空比 PWM
; 輸出 10% (1:9) 占空比 PWM
; 輸出 90% (9:1) 占空比 PWM

OUTPUT equ P1.0

Loop:
       clr   OUTPUT
       mov   A, #3
       call  Delay
       setb  OUTPUT
       mov   a, #7
       call  Delay
       ljmp  Loop

Delay:
       mov   r0, #0
DLoop:
       djnz  r0, DLoop
       djnz  acc, DLoop
       ret

       end