;IO口定义
dawr bit P3.6;
dula bit P2.6;
wela bit P2.7; 
csda bit P3.2;
aa   equ 40h



  clr wela;
  clr dula;
  clr csda;
  mov aa,0;
  clr dawr;
main:  
  mov P0,aa;
  mov 50h,#50
  call delayxms
  inc aa
  ajmp main

delayxms:mov 52h,#1         ;50h,51h,52h用于延时  50h为参数x  延时1*x ms
delaya: mov 51h,#125
        djnz 51h,$
        djnz 52h,delaya
        djnz 50h,delayxms
        ret ;延时返回