blink-2.c

#include <avr/io.h>

#define F_CPU 16000000l
#include <util/delay.h>

int main (void)
{
  DDRD = 0x02;
  PORTD = 0x02;
  while (1)
    {
      _delay_ms (250);
      PORTD ^= 0x02;
    }
  return 0;
}