void setup() {
  // put your setup code here, to run once:
 volatile char *dir;
  dir = 0x30;
  *dir = 0xFF;

}



void loop() {
  // put your main code here, to run repeatedly:
   volatile long i;
   volatile int j=1;
   volatile char *out;
   out = 0x31; 
   while(j<=128)
    {
      for(i=0;i<1000000;i++)
      *out=j;
      for(i=0;i<1000000;i++)
      *out=j<<1;
      j=*out;
      if(j==128)
      {
        while(j<=128)
        {
          for(i=0;i<1000000;i++)
            *out=j;
          for(i=0;i<1000000;i++)
           *out=j>>1;
           j=*out;

        }

      }
    }
   
    
}