void setup() {
  // put your setup code here, to run once:
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  Serial.begin(115200);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(2,LOW);
  digitalWrite(3,HIGH);
  digitalWrite(4,HIGH); 

  digitalWrite(7,LOW);
  digitalWrite(6,LOW);
  Serial.println("00");
  delay(1000);
  digitalWrite(6,HIGH);
  Serial.println("01");
  delay(1000);
  digitalWrite(6,LOW);
  digitalWrite(7,HIGH);
  Serial.println("10");
  delay(1000);
  digitalWrite(6,HIGH);
  Serial.println("11");
  delay(1000);
}