int pinA = 2;  // First digital pin
int pinB = 3;  // Second digital pin
int pinC = 4;  // Third digital pin

void setup() {
  Serial.begin(9600);       // Initialize serial communication
  pinMode(pinA, OUTPUT);    // Set pinA as an output pin
  pinMode(pinB, OUTPUT);    // Set pinB as an output pin
  pinMode(pinC, OUTPUT);    // Set pinc as an output pin
   Serial.println("Enter Channel Number:");
}

void loop() {
 
  if (Serial.available() > 0) {
    char input = Serial.read();  // Read the input from serial monitor
    int value = input - '0';     // Convert char to integer (ASCII to int)

    if (value >= 0 && value <= 7) {   // Only accept values 0, 1, 2, and 3
      Serial.print("Channel: ");
      Serial.println(value);

      // Convert the value to binary and output to the pins
      digitalWrite(pinA, bitRead(value, 0));  // Least significant bit (binary 1)
      digitalWrite(pinB, bitRead(value, 1));  // Most significant bit (binary 2)
      digitalWrite(pinC, bitRead(value, 2));  // Most significant bit (binary 3)
    }
    else if (value >7)
    {
      Serial.println ("Wrong Input");
    }
  }
}