KEY EQU 0000001B
LINE EQU P3.5

    LJMP START
    ORG 100H
START:
    LCALL LCD_INIT
    ; ustawienie wskaznika
    MOV R0,#CSDS
    MOV A, #KEY
    MOVX @R0,A

    MOV R5, #0ffH  ;high
    MOV R2, #0      ; 0-normal modes, 1-mode3
    LCALL WAIT_KEY
    MOV B, #2
    DIV AB

    JZ MODES_0X
    MOV A, B
    JZ MODE_10

MODE_11:    ;tryb 3
    MOV TMOD, #01110000B
    MOV R6, #0faH
    MOV R2, #1
    SJMP AFTER_SETUP

MODE_10:    ;tryb 2
    MOV TMOD, #01100000B
    MOV R5, #0faH
    MOV R6, #0faH
    SJMP AFTER_SETUP

MODES_0X:
    MOV A, B
    JZ MODE_10

MODE_01:    ;tryb 1
    MOV TMOD, #01010000B
    MOV R6, #0faH
    SJMP AFTER_SETUP

MODE_00:    ; tryb 0
    MOV TMOD, #01000000B
    MOV R6, #01aH

AFTER_SETUP:
    LCALL LCD_CLR
    MOV A, #00
    LCALL WRITE_HEX

    MOV A, R6
    MOV R1, A

    MOV TH1, R5
    MOV TL1, R6
    SETB TR1 ; start timera

LOOP:
    MOV A, R2
    JZ NORMAL
MODE3:
    JNB LINE, MODE3
    MOV A, #10
    LCALL DELAY_MS
    JNB LINE, MODE3
WAITFORIT:
    JB LINE, WAITFORIT
    MOV A, #10
    LCALL DELAY_MS
    JB LINE, WAITFORIT

    INC TL1
    MOV A, TL1
    JZ PRZEP
    ;end of mode3

NORMAL:
    JB TF1, PRZEP
    MOV A, TL1
    CLR C
    SUBB A, R1
    JZ LOOP

AFTER_PRZEP:
    LCALL LCD_CLR
    MOV R1, TL1
    MOV A, R1
    CLR C
    SUBB A, R6
    LCALL WRITE_HEX

    MOV A, #10
    LCALL DELAY_100MS
    SJMP LOOP

PRZEP:
    CLR TF1

    MOV TH1, R5
    MOV TL1, R6
    INC TL1

    SJMP AFTER_PRZEP
    NOP