;動態掃描數碼顯示程序
;P0口接J3，數據端口
;P2.2接 J2 B端子，表示段碼鎖存
;P2.3接 J2 A端子，標志位碼鎖存
ORG 00H
MOV 20H,#3FH   ;0
MOV 21H,#06H   ;1
MOV 22H,#5BH   ;2
MOV 23H,#4FH   ;3
MOV 24H,#66H   ;4
MOV 25H,#6DH   ;5

  LATCH1 BIT P2.2
  LATCH2 BIT P2.3

START:CALL SCAN
      JMP START
SCAN:MOV A,#0FEH    ;掃描子程序
      MOV R0,#20H
      SETB C
      MOV R2,#06H
LOOP:RLC A

     MOV P0,A
     SETB LATCH2
     CLR LATCH2
     MOV P0,@R0
     SETB LATCH1
     CLR LATCH1
     INC R0
     CALL DELAY
     DJNZ R2,LOOP
     MOV R2,#07H
     RET
DELAY:MOV R3,#1  ;掃描延時
D1:MOV R4,#2
D2:MOV R5,#248
   DJNZ R5,$
   DJNZ R4,D2
   DJNZ R3,D1
   RET
   END