void setup()
{
  // put your setup code here, to run once:
  volatile char *dir;
  dir = 0x30;
  *dir = 0xff;
}
void loop()
{
  volatile char x, *out ;
  volatile long i;
  out = 0x31;
  {
    for (x=4; x<=8; x++)
    {
    for (i = 1; i <100000; i++);
    *out = (1 <<x);
    }
  }
}