[C] Atmega32 przerwania. Zmienna nie działa w programie.

//Biblioteki

#include <avr\io.h>

#include <util/delay.h>

#include <avr\pgmspace.h>

#include <avr/signal.h>   

#include <avr/interrupt.h>

//Zmienne

unsigned char znak [10] PROGMEM = {0x3,0x9f,0x25,0x0D,0x99,0x49,0x41,0x1F,0x1,0x09,};

unsigned char nrzn ;

unsigned int licz;

//Program



int main(void)

{



sei();

DDRD = 0b1111;

DDRA = 255;

PORTD =0XE;

TCCR1B =4;

TIMSK =1<<TOIE1;

TCCR0 = 0x4D;



   

   for(;;)

   {

   _delay_loop_2(0xffff);

   PORTC = ~PORTC;

   

   PORTA = pgm_read_byte(&znak[nrzn]);   

   if(nrzn == 10)

   {

   nrzn = 0;

   }

   

   }

}



SIGNAL(SIG_OVERFLOW1)

{

DDRC = ~DDRC;

++nrzn;



}