#include <avr/io.h>
#define F_CPU 16000000UL
#include <util/delay.h>
#include <avr/interrupt.h>

/*
ISR(TIMER0_COMP_vect)
{
	static uint8_t licznik = 0;

	PORTB |= 0x0F;
	PORTA = LED[licznik];
	PORTB &= ~(1 << licznik);

	if (++licznik>3){
		licznik = 0;
	}

	switch(key_state1){
		case 0: if ((PINC & 0x01) == 0) key_state1 = 1;
		break;
		case 1: if ((PINC & 0x01) == 0) key_state1 = 2;
		else key_state1 = 0;
		break;
		case 2: break;
		case 3: if ((PINC & 0x01) != 0) key_state1 = 4;
		break;
		case 4: if ((PINC & 0x01) != 0) key_state1 = 0;
		else key_state1 = 3;
		break;
		default:key_state1 = 0;
	}

	switch(key_state2){
		case 0: if ((PINC & 0x02) == 0) key_state2 = 1;
		break;
		case 1: if ((PINC & 0x02) == 0) key_state2 = 2;
		else key_state2 = 0;
		break;
		case 2: break;
		case 3: if ((PINC & 0x02) != 0) key_state2 = 4;
		break;
		case 4: if ((PINC & 0x02) != 0) key_state2 = 0;
		else key_state2 = 3;
		break;
		default:key_state2 = 0;
	}
}

ISR()
{

}
uint8_t seg7[]={0b11000000,
	0b11111001,
	0b10100100,
	0b10110000,
	0b10011001,
	0b10010010,
	0b10000010,
	0b11111000,
	0b10000000,
0b10010000};

volatile uint8_t LED[4];
volatile uint8_t key_state1 = 0;
volatile uint8_t key_state2 = 0;

int main(void)
{
	TCCR0 |= (1 << WGM01 ) | (0 << WGM00 );
	TCCR0 |= (1 << CS02) | (0 << CS01) | (1 << CS00);
	OCR0=50;
	TIMSK |=(1 << OCIE0);
	sei();

	uint16_t sec = 0000;

	DDRB = 0x0F;
	DDRA = 0xFF;

	DDRC = 0x00;
	PORTC = 0x03;

	// Replace with your application code
	while (1)
	{
		uint16_t tmp = sec;

		LED[3]=seg7[tmp/1000];
		tmp %= 1000;
		LED[2]=seg7[tmp/100];
		tmp %= 100;
		LED[1]=seg7[tmp/10];
		tmp %= 10;
		LED[0]=seg7[tmp];

		if (key_state1 == 2){
			sec = 1234;
			key_state1 = 3;
		}
		else if(key_state2 == 2){
			sec = 4567;
			key_state2 = 3;
		}

	}
}