用查表方式显示数字。TO工作下方式0下。

SCAN EQU 28H
ORG 0000H
LJMP START
ORG  000BH
LJMP TIM0
ORG 0030H

START:MOV SP,#70H
MOV 2AH,#12H
MOV 2BH,#00H
MOV 2CH,#00H
MOV 20H,#0
MOV 21H,#0
MOV 22H,#0
MOV 23H,#0
MOV 24H,#2
MOV 25H,#1
MOV TMOD,#01H
MOV TH0,#3CH
MOV TL0,#0B0H
;MOV IE,#10000010B
MOV 41H,#20;R4
SETB EA
SETB ET0
SETB TR0

MAIN:
 LCALL DISPLAY
 LJMP MAIN
DISPLAY:
MOV R0,#20H
MOV SCAN,#0DFH

LD0:
MOV A,@R0
MOV DPTR,#TAB
MOVC A,@A+DPTR
CJNE R0,#22H,LD3
ORL A,#80H
LD3:CJNE R0,#24H,LD2
ORL A,#80H
LD2:MOV P0,A
SETB P2.6
CLR  P2.6
MOV A,SCAN
MOV P0,A
SETB P2.7
CLR P2.7 
ACALL DL1MS
INC R0
MOV A,SCAN
JNB ACC.0,LD1
RR A
MOV SCAN,A
AJMP LD0
LD1:RET

TIM0:MOV TH0,#3CH
MOV TL0,#0B0H
PUSH ACC
PUSH B
PUSH PSW
DJNZ 41H,X2
MOV 41H,#20
CALL CLOCK1
CALL CLOCK2
X2:POP PSW
POP B
POP ACC
RETI

CLOCK1:MOV A,2CH
ADD A,#1
DA A
MOV 2CH,A
CJNE A,#60H,X4
MOV 2CH,#00
MOV A,2BH
ADD A,#1
DA A
MOV 2BH,A
CJNE A,#60H,X4
MOV 2BH,#00
MOV A,2AH
ADD A,#1
DA A
MOV 2AH,A
CJNE A,#24,X4
MOV 2AH,#00
X4:RET

CLOCK2:
MOV A,2CH
MOV B,#10H
DIV AB
MOV 20H,B
MOV 21H,A
MOV A,2BH
MOV B,#10H
DIV AB
MOV 22H,B
MOV 23H,A
MOV A,2AH
MOV B,#10H
DIV AB
MOV 24H,B
MOV 25H,A
RET

TAB:
  DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H
  DB 7FH,6FH,77H,7CH,39H,5EH,79H,71H
 DL1MS:MOV R6,#14H
 DL1:MOV R7,#19H
 DL2:DJNZ R7,DL2
 DJNZ R6,DL1
 RET

 DELAY:MOV R6,#60
 D1:MOV R7,#248
 DJNZ R7,$
 DJNZ R6,D1
 RET
 END