int main()
{
    alt_sys_init();
    IOWR_ALTERA_AVALON_PIO_DATA(PIO_OUT_BASE, 0);
    Delay(0xFFFF);
    IOWR_ALTERA_AVALON_PIO_DATA(PIO_OUT_BASE, 1);
...
...

Delay(0xFFFF);

void Delay(int _d)
{
    volatile int i = 0;
    for(i =0; i < _d; i++);
}

/* process the registered callbacks */

  while (alarm != (alt_alarm*) &alt_alarm_list)
  {
    next = (alt_alarm*) alarm->llist.next;

    /*
     * Upon the tick-counter rolling over it is safe to clear the
     * roll-over flag; once the flag is cleared this (or subsequnt)
     * tick events are enabled to generate an alarm event.
     */
    if ((alarm->rollover) && (_alt_nticks == 0))
    {
      alarm->rollover = 0;
    }
    
    /* if the alarm period has expired, make the callback */    
    if ((alarm->time <= _alt_nticks) && (alarm->rollover == 0))
    {
      next_callback = alarm->callback (alarm->context);

      /* deactivate the alarm if the return value is zero */

      if (next_callback == 0)
      {
        alt_alarm_stop (alarm);
      }
      else
      {
        alarm->time += next_callback;
        
        /*
         * If the desired alarm time causes a roll-over, set the rollover
         * flag. This will prevent the subsequent tick event from causing
         * an alarm too early.
         */
        if(alarm->time < _alt_nticks)
        {
          alarm->rollover = 1;
        }
      }
    }
    alarm = next;
  }