中断时间的问题

只看该作者 · 2007-12-27 21:23

各位大哥,帮忙看下中断时间设置的对不对,我采用6MHZ的频率,整体程序是1S数字加一,可实际仿真时,却是13S左右加一,真奇怪;麻烦各位大哥帮忙看看,程序哪出了问题,为什么会是过13S加一呢?而不是过1S加一呢?
ajmp main
    org 0bh
    acall zd
back:
    reti
main:mov dptr,#tab
    mov r6,#10
    mov 30h,#0
    mov 31h,#0
    mov 32h,#0
     mov tmod,#1
    mov th0,#3ch
    mov tl0,#0b0h
    setb ea
  setb et0
  setb tr0
loopo:mov r1,#30h
      mov r7,#0f7h
loopi:mov p2,#0ffh
      mov a,@r1
      movc a,@a+dptr
      mov p0,a
      mov p2,r7
      inc r1
      mov a,r7
      rr a
      mov r7,a
      cjne r7,#7fh,loopi
      sjmp loopo
zd:
   mov th0,#3ch
   mov tl0,#0b0h
   djnz r6,back
   mov r0,#30h
   inc @r0
   cjne @r0,#10,back
   mov 30h,#0
   inc r0
   inc @r0
   cjne @r0,#10,back
   mov 31h,#0
   inc r0
   inc @r0
   cjne @r0,#10,back
   mov 32h,#0
   reti
tab:db 0c0h,0f9h,0a4h,0b0h,99h,92h,82h,0f8h,80h,90h,88h
   end