void setup() {
  // put your setup code here, to run once:
volatile char*dirf;
dirf=0x30;
volatile char*outf;
outf=0x31;
*outf=0x01;
}

void loop() {
  // put your main code here, to run repeatedly:
char x;
volatile char i;
  volatile long m;
volatile char*outf;
outf=0x31;
for(i=0;i<=8;i++)
{
  x=1 << i; 
  for(m=0;m< 180000;m++);
  *outf=x;
}
}