ORG 0000H
        SJMP MAIN
        ORG 0003H    ；INT0中斷向量
        SJMP INTT0
        ORG 0030H
MAIN:
        CLR IT0    ;   IT0=0時，INT0低態動作
        SETB EX0    ；中斷INT0開關，EX0=1起用INT0中斷功能
        SETB EA     ； 中斷總開關 EA=1可啟用所有中斷
        MOV 40H,#1
        MOV R0,#1
       ; MOV R1,#1
LOOP:   ACALL DISPLAY1
        SJMP LOOP

INTT0:   CLR EA      ;
        PUSH PSW
        PUSH ACC    ；將ACC的內容存到堆站
        JNB P1.0,S1
        JNB P1.1,S2
        JNB P1.2,S3
        JNB P1.3,S4
        JNB P1.4,S5
        JNB P1.5,S6
        JNB P1.6,S7
        JNB P1.7,S8
RETUP:  POP ACC
        POP PSW
        ;CLR IT0
        ;SETB EX0
        SETB EA
        RETI

S1:     MOV R0,#1
        ACALL DISPLAY
        AJMP RETUP

S2:     MOV R0,#2
        ACALL DISPLAY
        AJMP RETUP

S3:     MOV R0,#3
        ACALL DISPLAY
        AJMP RETUP

S4:     MOV R0,#4
        ACALL DISPLAY
        AJMP RETUP

S5:     MOV R0,#5
        ACALL DISPLAY
        AJMP RETUP

S6:     MOV R0,#6
        ACALL DISPLAY
        AJMP RETUP

S7:     MOV R0,#7
        ACALL DISPLAY
        AJMP RETUP

S8:     MOV R0,#8
        ACALL DISPLAY
        AJMP RETUP

DISPLAY:
        MOV 30H,40H
        MOV 40H,R0
        MOV R0,30H

DISPLAY1:
        MOV P2,#00H
        CLR P3.0
        CLR P3.1
        MOV DPTR,#TAB
LOOP11: MOV A,R0
        MOV 42H,A
        MOVC A,@A+DPTR
        MOV P2,A
        SETB P3.1
        CALL DELAY
        CLR P3.1
        MOV A,42H
        CJNE A,40H,QQ
        RET

QQ:     JNC QQ1    ;若CY=0就眺到QQ1
        INC R0     ；將R0加1
        SJMP LOOP11
QQ1:    DEC R0      ；將R0減1
        SJMP LOOP11

TAB:    DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H

DELAY:  MOV R7,#250
DEL1:   MOV R6,#250
DEL2:   MOV R5,#4
DEL3:   DJNZ R5,DEL3
        DJNZ R6,DEL2
        DJNZ R7,DEL1
        RET
        END