klawiatura

ROW EQU 0F8H
COL EQU 0DBH
LED EQU P1

ORG 0
MOV R0, #0  ;wiersze
MOV R1, #0  ;kolumny
PETLA:

        MOV A, #01111111B
        LCALL RD_ROW


SJMP PETLA


RD_ROW:
    ANL A, #11110000B
    ANL ROW, #00001111B
    ORL ROW, A

    MOV A, COL
    CPL A
    ANL A, #00001111B

    CLR C
    JZ NO_BUTTON

    MOV R0, #0
IIr:
    RRC A
    JC IS_BUTTON
    INC R0
    SJMP IIr

IS_BUTTON:
    MOV A,R0             ;R0 numer wiersza
NO_BUTTON:
    MOV P1, #01111111B
    RET


RD_COL:
; COL3..0 <- ACC3..0

    CPL A
    MOV R1, #0
IIc:
    RRC A
    JC Ic
    INC R0
    SJMP IIc
Ic: MOV A,R1             ;R1 numer kolumny


    RET

NUM_BUTTON:
    MOV A, R0
    MOV B, #4
    MUL AB
    ADD A, R1           ;A = 4*wiersz + kolumna

    RET

END