basic_receive.ino

const int LEDPIN = 6;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.setTimeout(200);
  
  pinMode(LEDPIN, OUTPUT);
  pinMode(LED_BUILTIN, OUTPUT);
}
  
void loop() {
  // put your main code here, to run repeatedly:

  while (Serial.available()) {
    uint16_t inValue = Serial.read();
    analogWrite(LEDPIN, inValue);
    Serial.println(inValue);
    //Serial.flush();
  }

  if (millis() % 1000 > 900) digitalWrite(LED_BUILTIN, HIGH);
  else digitalWrite(LED_BUILTIN, LOW);
}