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

}

void loop() {
  // put your main code here, to run repeatedly:
  // ******************************************
  // Blink First LED (With Delay)
  //volatile char *output;
  //volatile long i;
  //output = 0x31;
  //for (i = 0; i < 100000; i++);
  //*output = 1 << 0x00;
  //for (i = 0; i < 100000; i++);
  //*output = 0x00;
  // ******************************************
  // Blink all the 8 LEDs (with delay)
  //volatile char *output;
  //volatile long i;
  //output = 0x31;
  //for (i = 0; i < 100000; i++);
  //*output = 0xFF;
  //for (i = 0; i < 100000; i++);
  //*output = 0x00;
  // ******************************************
  // Glow the LEDs one by one (Do not off the LED)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 0; x < 8; x++) {
  //  *output |= 1 << x;
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow the LEDs one by one(at a time one LED should glow)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 0; x < 8; x++) {
  //  *output = 1 << x;
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow the EVEN LEDs one by one (Do not off the LED)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 0; x < 8; x++) {
  //  if (x % 2 == 0) {
  //    *output |= 1 << x;
  //  }
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow the ODD LEDs one by one (Do not off the LED)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 0; x < 8; x++) {
  //  if (x % 2) {
  //    *output |= 1 << x;
  //  }
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow 0 to 3 LEDs (one by one)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 0; x < 3; x++) {
  //  *output |= 1 << x;
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow 4 to 7 LEDs (one by one)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 3; x < 7; x++) {
  //  *output |= 1 << x;
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow 3 to 0 LEDs (one by one)
  //volatile char *output;
  //char x;
  //volatile long i;
  //output = 0x31;
  //for (x = 3; x >= 0; x--) {
  //  *output |= 1 << x;
  //  for (i = 0; i < 100000; i++);
  //}
  // ******************************************
  // Glow 7 to 4 LEDs (one by one)
  volatile char *output;
  char x;
  volatile long i;
  output = 0x31;
  for (x = 6; x >= 3; x--) {
    *output |= 1 << x;
    for (i = 0; i < 100000; i++);
  }
}