DISBUF   EQU  30H
BUF      EQU  20H
SECBUF   EQU  21H
MINBUF   EQU  22H
HOURBUF  EQU  23H
P_CON    EQU  0FF20H
PORT_A   EQU  0FF21H
PORT_B   EQU  0FF22H
        ;
        ORG 0000H
        LJMP START
        ;
        ORG 000BH
        LJMP CLOCK
        ;
        ORG 0030H
START:  MOV SP,#60H
        MOV DPTR,#P_CON
        MOV A,#03H
        MOVX @DPTR,A
        ;
        MOV A,#00H
        MOV R1,#06H
        MOV R0,#DISBUF
LP1:    MOV @R0,A
        INC R0
        DJNZ R1,LP1
        ;
        ANL TMOD,#0F0H
        ORL TMOD,#01H
        MOV TL0,#0B0H
        MOV TH0,#3CH
        ;
        MOV BUF,#00H
        MOV SECBUF,#00H
        MOV MINBUF,#59H
        MOV HOURBUF,#23H
        SETB TR0
        SETB ET0
        SETB EA
        ;
DISP1:  MOV R0,#DISBUF
        MOV A,SECBUF
        ANL A,#0FH
        MOV @R0,A
        INC R0
        MOV A,SECBUF
        SWAP A
        ANL A,#0FH
        MOV @R0,A
        INC R0
        ;
        MOV A,MINBUF
        ANL A,#0FH
        MOV @R0,A
        INC R0
        MOV A,MINBUF
        SWAP A
        ANL A,#0FH
        MOV @R0,A
        INC R0

        MOV A,HOURBUF
        ANL A,#0FH
        MOV @R0,A
        INC R0
        MOV A,HOURBUF
        SWAP A
        ANL A,#0FH
        MOV @R0,A
        ;
        LCALL DISPLAY
        SJMP DISP1
        ;
DISPLAY:MOV R0,#DISBUF+5
        MOV R2,#20H
DIS_LP: MOV DPTR,#SEG_TAB
        MOV A,@R0
        MOVC A,@A+DPTR
        MOV DPTR,#PORT_B
        MOVX @DPTR,A
        ;
        MOV DPTR,#PORT_A
        MOV A,R2
        MOVX @DPTR,A
        ;
        MOV R3,#00H
        DJNZ R3,$
        ;
        DEC R0
        MOV A,R2
        RR A
        MOV R2,A
        JNB ACC.7,DIS_LP
        ;
        RET
        ;
SEG_TAB:DB 0C0H
        DB 0F9H
        DB 0A4H
        DB 0B0H
        DB 99H
        DB 92H
        DB 82H
        DB 0F8H
        DB 80H
        DB 90H
        ;
CLOCK:  MOV TL0,#0B0H
        MOV TH0,#3CH
        PUSH PSW
        PUSH ACC
        ;
        MOV A,BUF
        ADD A,#01H
        MOV BUF,A
        CJNE A,#0AH,INT_DONE
        ;
        MOV BUF,#00H
        MOV A,SECBUF
        ADD A,#01H
        DA A
        MOV SECBUF,A
        ;
        CJNE A,#60H,INT_DONE
        MOV SECBUF,#00H
        ;
        MOV A,MINBUF
        ADD A,#01H
        DA A
        MOV MINBUF,A
        ;
        CJNE A,#60H,INT_DONE
        MOV MINBUF,#00H
        ;
        MOV A,HOURBUF
        ADD A,#01H
        DA A
        MOV HOURBUF,A
        ;
        CJNE A,#24H,INT_DONE
        MOV HOURBUF,#00H

INT_DONE:POP ACC
        POP PSW
        RETI
        END