ORG 1BH                中斷源入口地址:1BH      
       MOV TH1,#0ECH     T1的高位為0ECH
       MOV TL1,#78H        T1的低位為78H
       DJNZ R6,BACK        判斷R6-1=0?    ≠0則跳轉到BACK  =0向下運行
       MOV R6,#200       
     
AJ:    MOV R0,#35H                      ;秒
       INC @R0
       CJNE @R0,#10,$+3
       JC BACK
       MOV @R0,#0
       MOV R0,#34H
       INC @R0
       CJNE @R0,#6,$+3
       JC BACK
       MOV @R0,#0
      

AJ1:   MOV R0,#33H                       ;分
       INC @R0
       CJNE @R0,#10,$+3
       JC BACK
       MOV @R0,#0
       MOV R0,#32H
       INC @R0
       CJNE @R0,#6,$+3
       JC BACK
       MOV @R0,#0
      
      
AJ2:   MOV R0,#31H                          ;時     R0=31H
       INC @R0                                            (31H)中的內容+1
       CJNE @R0,#4,$+3                              =?4    ≠往下
       JC BACK                                           C為1轉移BACK
       CJNE @R0,#5,$+3                            =?5   ≠往下
       JC S24                                               為24轉移S24
       CJNE @R0,#10,$+3                          =?10  ≠往下
       JC BACK                                             C為1轉移BACK
       MOV @R0,#0                                     給@R0賦值為0
       MOV R0,#30H                                     R0=30H
       INC @R0                                            @R0+1
BACK:  RETI                                             返回
S24:   DEC R0                                          R0-1
       CJNE @R0,#2,$+3                            =?2  ≠往下
       JC BACK                                             C為1轉移到BACK
       MOV @R0,#0                                    再將@R0=0
       MOV 31H,#0                                     將31H=0
       RETI                                                返回

MAIN:  MOV R1,#30H                               最初始:R1=31H
       MOV @R1,#0                                            @R1=0H
  INC R1                                                        將R1+1
       CJNE R1,#36H,MAIN+2                    =?36        ≠往下
  MOV P3,#0FFH                                      P3賦值0FFH  
       MOV P0,#0                                     P0為0

       MOV DPTR,#SEGPT                        16位數據指針寄存器賦值,在SEGPT中找
       MOV R6,#200                                R6=200
       MOV TMOD,#10H
       MOV TH1,#0ECH
       MOV TH1,#78H
       SETB IT0
  SETB IT1
       MOV IP,#15H
       MOV IE,#9FH
       SETB TR1
LOOPO: MOV R1,#30H
       MOV R7,#20H
LOOPI: MOV P2,#0
       MOV A,@R1
       MOVC A,@A+DPTR
       MOV P1,A   
       MOV P2,R7
       INC R1
       MOV A,R7
       RR A
       MOV R7,A
       CJNE R7,#80H,LOOPI
       SJMP LOOPO
SEGPT: DB 40H,79H,24H,30H,19H,12H,2,78H,0,18H
       END


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