.include "8535def.inc"
rjmp reset
tab:.db $3f,$06,$5b,$4f,$66,$6d,$7d,$07,$7f,$6f  ;七段碼表
reset:ldi r16,$02            ;棧指針置初值
      out sph,r16          
      ldi r16,$5f
      out spl,r16
      ldi r16,0              ;定義B口輸入帶上拉 
      ldi r16,$ff            
      out portb,r16
      out ddrc,r16           ;定義C口、D口為輸出
      out ddrd,r16
      in r20,pinb            ;讀B口引腳
      com r20                ;取反
      mov r21,r20
      andi r16,$0f           ;取個位BCD碼
      swap r21               ;半字節交換
      andi r17,$0f           ;取十位BCD碼
      ldi ZH,high(tab*2)     ;查個位七段碼
      ldi ZL,low(tab*2)
      add ZL,r16
      lpm
      out portc,r0           ;送C口靜態輸出
      ldi ZH,high(tab*2)     ;查十位七段碼
      ldi ZL,low(tab*2)
      add ZL,r17
      lpm
      out portd,r0          ;送D口靜態輸出
h:    rjmp  h