void setup() {
  // put your setup code here, to run once:
  Serial.begin(19200);
  Serial.println("7 segment LED test...");

  //Setup once for pin 0~7 (pord D) to output mode
  //DDRD = B1111111;
  for ( byte i = 0; i < 7; i ++ ){
    pinMode(i, OUTPUT);//Setup once for pin 0~7 to output mode
  }
}

byte index = 0;
const byte LEDs[10] = {
  B0000001, //0
  B1001111, //1
  B0010010, //2
  B0000110, //3
  B1001100, //4
  B0100100, //5
  B0100000, //6
  B0001111, //7
  B0000000, //8
  B0000100  //9
};
void loop() {
  // put your main code here, to run repeatedly:
  PORTD = LEDs[index];
  //digitalWrite(3, HIGH);
  index++;
  Serial.println( LEDs[index] );

  if ( index == 10 ){
    index = 0;
  }

  delay(1000);
}