;port 1 is output connect to 7 segment display
;port 2.0 is puls connect to button
;port 2.1 is minor connect to button
;.,a,b,c,d,e,f,g
;delay=0.005s

        ORG 0000H
START:  MOV R0, #00H
        MOV DPTR, #DATA
        MOV A, R0
        MOVC A, @A+DPTR
        MOV P1, A
        MOV P2, #0FFH
KEY:    JNB P2.0, LOOP
        JNB P2.1, LOOP1
        AJMP KEY
;==========
;=  PLUS  =
;==========
LOOP:   ACALL DELAY
        CJNE R0, #OK-DATA, RUN
        MOV R0, #0
        AJMP OUTPUT
RUN:    INC R0
OUTPUT: MOV A, R0
        MOVC A, @A+DPTR
        MOV P1,A
TEST2:  JNB P2.0, TEST2 
        ACALL DELAY             
        AJMP KEY
;===========
;=  MINUS  =
;===========
LOOP1:  ACALL DELAY
        CJNE R0, #0, RUN1
        MOV R0, #OK-DATA+1
RUN1:   DEC R0
        MOV A, R0
        MOVC A, @A+DPTR
        MOV P1,A
TEST3:  JNB P2.1, TEST3
        ACALL DELAY
        AJMP KEY
;================
;=    DELAY     =
;================
DELAY:  MOV R6, #21
DL1:    MOV R7, #118
DL2:    DJNZ R7, DL2
        DJNZ R6, DL1 
        RET
;================
;=     DATA     =
;================
DATA:   DB      00000001B       ;0
        DB      01001111B       
        DB      00010010B       
        DB      01001100B       
        DB      00010010B       
        DB      00100000B       
        DB      00001111B       
        DB      00000000B       
OK:     DB      00000100B       ;9
        END