ORG 0000H
          AJMP MAIN
          ORG 0003H
          AJMP SERVE          ;中斷入口

          ORG 0060H
MAIN:     MOV A,#82H             ;工作方式控制字
          MOV DPTR,#8003H
          MOVX @DPTR,A
          SETB IT0
          SETB EX0
          SETB EA
LOOP:     MOV A,#90H            ;東西南北全為紅燈
          MOV DPTR,#8000H
          MOVX @DPTR,A
          ACALL DELAY
NLDH:     MOV A,#84H             ;南北為綠，東西為紅
          MOVX @DPTR,A
          ACALL DELAY
NHDH:     MOV R0,#03H
NHDH1:    MOV A,#80H              ;  閃燈
          MOVX @DPTR,A
          ACALL DELAY2
          DJNZ R0,TEMP1
          AJMP NHUDH

NHUDH:    MOV  A,#88H
          MOVX @DPTR,A
          ACALL DELAY3
NHDL:     MOV A,#30H
          MOVX @DPTR,A
          ACALL DELAY
NHDHU:    MOV R0,#3
          
NHDHU1:   MOV A,#10H
          MOVX @DPTR,A
          ACALL DELAY2
          DJNZ R0,TEMP2
          AJMP NHDXH

NHDXH:    MOV A,#50H
          MOVX @DPTR,A
          ACALL DELAY3
          AJMP NLDH
TEMP1:    MOV A,#84H
          MOVX @DPTR,A
          ACALL DELAY2
          AJMP NHDH1
          
TEMP2:    MOV A,#30H
          MOVX @DPTR,A
          ACALL DELAY2
          AJMP NHDHU1          
SERVE:    PUSH ACC
          PUSH PSW
          MOV A,#90H
          MOV DPTR,#8000H
          MOVX @DPTR,A
          ACALL DLY
          POP PSW
          POP ACC
          RETI

DELAY: MOV R5,#30
       MOV R6,#00H
       MOV R7,#00H
       
DELAYLOOP: DJNZ R6,DELAYLOOP
           DJNZ R7,DELAYLOOP
           DJNZ R5,DELAYLOOP
           RET

DELAY2: MOV R6,#00H
        MOV R7,#00H
DELAYLOOP2: DJNZ R6,DELAYLOOP2
            DJNZ R7,DELAYLOOP2
              RET

DELAY3:     MOV R5,#10
            MOV R6,#00H
            MOV R7,#00H
DELAYLOOP3: 
            DJNZ R6,DELAYLOOP3
            DJNZ R7,DELAYLOOP3
            DJNZ R5,DELAYLOOP3
            RET

DLY:        MOV R1,#10
            MOV TMOD,#01H
            MOV TH0,#3CH
            MOV TL0,#0B0H
            MOV IE,#00H
            SETB TR0
CX:         JNB TF0,CX
            DJNZ R1,CXX
            AJMP FH
CXX:        MOV TH0,#3CH
            MOV TL0,#0B0H
            AJMP CX
FH:         RET