const int comPin = 2;
const int controlPins[] = { 6, 5, 4, 3 };

int readMux(int channel) 
{
  for(int i = 0; i < 4; i++) 
    digitalWrite(controlPins[i], bitRead(channel,i) == 0 ? LOW : HIGH);
  delay(10);
  return digitalRead(comPin);
}

void setup() 
{
  Serial.begin(115200);
  pinMode(comPin, INPUT);
  for (int i = 0; i < 4; i++) 
    pinMode(controlPins[i], OUTPUT);
}

void loop() 
{
  for(int i = 0; i < 16; i++) 
    Serial.print( readMux(i) == LOW ? "0" : "1");
  Serial.println();
  delay(500);
}