TAJMERI

#include <avr/io.h>
#include <avr/interrupt.h>
const unsigned char simboli[] = {
 0x0c, 0xa4, 0x27, 0xc4
}; //look-up tabela sa simbolima A,b,C,d
unsigned char DISP_BAFER[4] = {
 0xfe, 0xfe, 0xfe, 0xfe
}; //bafer displeja
unsigned long millis;
unsigned char disp = 3;

unsigned char digitToDisp(int digit)
{
	switch(digit)
	{
	case 0:
		return 0x05;
	case 1:
		return 0xdd;
	case 2:
		return 0x46;
	case 3:
		return 0x54;
	case 4:
		return 0x9c;
	case 5:
		return 0x34;
	case 6:
		return 0x24;
	case 7:
		return 0x5d;
	case 8:
		return 0x04;
	case 9:
		return 0x14;
	}
}

void numToBuffer(int num, unsigned char *buf)
{
	buf[3] = digitToDisp(num % 10);
	num /= 10;

	//bez vodecih nula
	buf[2] = (num % 10) ? digitToDisp(num % 10) : 0xff;
	num /= 10;
	buf[1] = (num % 10) ? digitToDisp(num % 10) : 0xff;
	num /= 10;
	buf[0] = (num % 10) ? digitToDisp(num % 10) : 0xff;
}


ISR(TIMER0_COMPA_vect)
{
 //prekid tajmera 0 usled dostizanja vrednosti registra OCR0A
 if (++disp > 3)
 disp = 0;
 //if(!(millis % 1000))

	 PORTB = ~(1 << (3-disp)); //ukljucenje tranzistora
	 PORTD = DISP_BAFER[disp]; //ispis na trenutno aktivan displej

 millis++; //sistemsko vreme
}
int main()
{
 unsigned long t0;
 unsigned char i;
 //inicijalizacija portova:
 DDRB = 0x0f; //PB3-PB0 -> izlazi
 DDRD = 0xff; //port D -> izlaz
 //inicijalizacija tajmera 0:
 TCCR0A = 0x02; //tajmer 0: CTC mod
 TCCR0B = 0x03; //tajmer 0: fclk = fosc/64
 OCR0A = 249; //perioda tajmera 0: 250 Tclk (OCR0A + 1 = 250)
 TIMSK0 = 0x02; //dozvola prekida tajmera 0
 //usled dostizanja vrednosti registra OCR0A
 sei(); //I = 1 (dozvola prekida)
 int number = 0;
 while(1)
 {
	 t0 = millis;
	 while ((millis - t0) < 1000); //pauza 1000ms

	 //for (i = 0; i < 4; i++)
	 //DISP_BAFER[i] = simboli[i];
		 numToBuffer(number, DISP_BAFER);
		 ++number;
	 //t0 = millis;
	 /*while ((millis - t0) < 500); //pauza 500ms
	 for (i = 0; i < 4; i++)
	 DISP_BAFER[i] = 0xfe;*/
 }
 return 0;
}