int main ()
{
  DDRC |= 0x0f;

  set_wgm1(CTC_OC);
//  TCCR1B = (1<<WGM12);
  
  OCR1A = 15624;
  TIMSK |= (1<<OCIE1A);

 set_cs1(PS1024);
 // TCCR1B |= (1<<CS00);
  sei();
  while (1)
  {
  
  }
}


ISR (SIG_OUTPUT_COMPARE1A)
{
  static uint8_t i=0x00;
  static uint32_t rand; //=0x69a5391b;
  if (i == 0 )rand = random();
  PORTC = 1 << ((rand >> (2 * i)) & 0x03);
  if (i<16) i++; 
  else i=0;
}