#ifndef F_CPU
#define F_CPU 1000000UL
#endif

#include <avr/io.h>
#include <util/delay.h>
int main(void)
{
     DDRA=0x01;
    while(1)
    {
      PORTA=0x01;
      _delay_ms(1000);
      PORTA=0x01;
      _delay_ms(1000);
    }
  }