int DP_LED = 16;
int Red_LED = 3;
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by
int command;
int sensorPin = A0;  // input pin for the potentiometer
int digitalValue = 0;// variable to store the value coming from the sensor


// the setup function runs once when you press reset or power the board
void setup() {
  Serial1.begin(9600);

  pinMode(16, OUTPUT);
  pinMode(3, OUTPUT);

  Serial1.begin(115200);
  delay(100);

  Serial1.println("Type s to start!\n");

  while(!Serial1.available() > 0);
  command = Serial1.read();
  
  if(command == 's'){
    Serial1.println("Blinking DP LED every 500ms!");
  }
  else {
    Serial1.println("Command is wrong!");
    exit(1);
  } 
}
// the loop function runs over and over again forever
void loop() {

  analogWrite(Red_LED, brightness); // set the brightness of led by changing the PWM value
  
  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;
  
  // reverse the direction of the fading at the ends of the fade:
  if (brightness <= 0 || brightness >= 255) {
  fadeAmount = -fadeAmount;
  }
  delay(30); // wait for 30 milliseconds to see the dimming effect

  digitalWrite(DP_LED, HIGH);  // turn the DP LED off (HIGH is the voltage level)
  Serial1.print("DP LED is OFF!\n");
  delay(500);                      

  digitalWrite(DP_LED, LOW);  // turn the DP LED on 
  Serial1.print("DP LED is ON!\n");
  delay(500);  

  digitalValue = analogRead(sensorPin);// read the value from the analog channel
  Serial1.print("digital value = ");
  Serial1.println(digitalValue);        //print digital value on serial monitor
}