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

void loop() {
  // put your main code here, to run repeatedly:
    volatile char *output=0x31;
    int i;
    int f=1;
    for(int i=0;i<=8;i++){
          *output=((1<<i)|f);
          f=((1<<i)|f);
          volatile long k;
          for(k=0;k<=1000000;k++);
    }
}