求大神指点，单片机实验，设计数字秒表。具体要求如下

Question

用动态扫描方法和定时器1在数码管的后4位上显示出秒表，精确到0.1秒，最大显示999.9秒，一直循环下去，使用12MHz晶振。
在线等候指点，或者加QQ1531952459指教，感谢ing

Answer 1

wolf_lhy,小龙出世正帮你修改,请采纳,谢谢!

Answer 2

ORG 0000H
STAR:MOV P1,#0FFH
MOV A,P1
CPL A
ANL A,#78H
JZ STAR
ACALL DELY
MOV A,P1
CPL A
ANL A,#78H
JZ STAR
JB ACC.3,L1

L1:AJMP SMG
SMG:MOV P2,#0FFH
MOV DPTR,#TAB
MOV R2,#0
MOV R3,#0
MOV R4,#0
MOV R5,#0

SMG1:MOV A,R2
MOVC A,@A+DPTR
MOV P0,A
MOV P2,#01H
ACALL SMGDELY
SMG2:MOV A,R3
MOVC A,@A+DPTR
MOV P0,A
MOV P2,#02H
ACALL SMGDELY
SMG3:MOV A,R4
MOVC A,@A+DPTR
MOV P0,A
MOV P2,#04H
ACALL SMGDELY
SMG4:MOV A,R5
MOVC A,@A+DPTR
MOV P0,A
MOV P2,#08H
ACALL SMGDELY

INC R2
CJNE R2,#10,SMG1
INC R3
MOV R2,#0
CJNE R3,#6,SMG2
INC R4
MOV R3,#0
CJNE R4,#10,SMG3
INC R5
MOV R4,#0
CJNE R5,#6,SMG4
SJMP SMG

DELY:MOV R5,#02H
DELY1:MOV R6,#0FFH
DELY2:MOV R7,#7DH
DELY3:NOP
NOP
DJNZ R7,DELY3
DJNZ R6,DELY2
DJNZ R5,DELY1
RET
SMGDELY:MOV R0,#25
SMGDELY1:MOV R1,#40
SMGDELY2:NOP
NOP
DJNZ R1,SMGDELY2
DJNZ R0,SMGDELY1
RET
TAB:DB 3FH
DB 06H
DB 5BH
DB 4FH
DB 66H
DB 6DH
DB 7DH
DB 07H
DB 7FH
DB 6FH
END

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