#include <avr/io.h>
#include <avr/interrupt.h>

static volatile uint8_t Seg7Code[] = {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};

static volatile uint8_t Delay[] = {0, 50, 25, 16, 13, 10, 8, 7, 6, 5}; //[0] <- Error ; [0][1] <- Aufgabenbedingt ungültig

static volatile int Position = 4, toggle = 0, i = 0;

void set(){
	PORTC = Seg7Code[Position];

	i = 0;
}

void init(){
	DDRA |= 0xFF;	//Summer
	DDRC |= 0xFF;	//seg7-Anzeige

	DDRD &=~ ((1 << PD2) | (1 << PD3));
	PORTD |= (1 << PD2) | (1 << PD3);

	GICR |= (1 << INT0) | (1 << INT1);
	MCUCR |= (1 << ISC01) | (1 << ISC11);

	TCCR1B |= (1 << WGM12) | (1 << CS10);

	OCR1A = 400; //0.1 ms

	sei();
}

ISR(INT0_vect){//+100Hz
	cli();

	Position = (Position == 9) ? Position : Position + 1;

	set();

	sei();
}

ISR(INT1_vect){//-100Hz
	cli();

	Position = (Position == 2) ? Position : Position - 1;

	set();

	sei();
}

ISR(TIMER1_COMPA_vect){
	if(i == Delay[Position]){
		PORTA = (toggle == 0) ? 0xFF : 0x00;

		toggle = (toggle == 0) ? 1 : 0;

		i = 0;
	}
	else i++;
}

int main(){
	init();

	PORTC = Seg7Code[Position];

	TIMSK |= (1 << OCIE1A);

	while(1){}

	return 0;
}