void setup() {
  // put your setup code here, to run once:
  DDRC = B11111111; // Pins 30 to 37
}

void loop() {
  // put your main code here, to run repeatedly:
  static bool direction = false;
  static byte b = B00000001;
  PORTC = b;
  if (!direction) {
    b = b << 1;
  }
  else {
    b = b >> 1;
  }
  if (b == B10000000) {
    direction = true;
  }
  else if (b == B00000001) {
    direction = false;
  }
  delay(100);
}