int potPin = 4;  
int ledPin = 2;  

void setup() {
  Serial.begin(115200); 

  Serial2.begin(9600, SERIAL_8N1, 16, 17); 
  pinMode(potPin, INPUT);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  int Value = analogRead(potPin);  
  int Mapped = map(Value, 0, 4095, 0, 255);  
  
  
  Serial2.write(Mapped);
  
  
  if (Serial2.available()) {
    int recValue = Serial2.read(); 
    analogWrite(ledPin, recValue);  
  } 
}