ATmega328PB and port PC2 problem

[13LenD]

I'm working with the minicore bootloader on an ATmega 328BP version 3.0.2 Now I try to use the digital port PC2, but it does not give a normal response as I expected? This port is externally pulled to 0V or to 5V. So I would expect a high or low but instead I see a 16 in my serial monitor? are there more people with this problem? See the code used below:

const int Motion = PIN_PC2;       //Input motion input
const int Twilight = A3;          //Input twilight input 

void setup() {
  // initialize PWM pin Warm light as an output.
  pinMode(Motion, INPUT);
  pinMode(Twilight, INPUT);
  Serial.begin(9600);
}

// the loop function runs over and over again forever
void loop() {

  //Read the poteniometer value
  int TwilightValue = analogRead(Twilight);

  Serial.print("Twilight: ");
  Serial.println(TwilightValue);
  Serial.print("Motion: ");
  Serial.println(Motion);

delay(100);

}

[MCUdude]

That's because PIN_PC2 is defined as 16: https://github.com/MCUdude/MiniCore/blob/0bb50f6a6648e37cbe53012c61322345847c2a03/avr/variants/standard/pins_arduino.h#L172

Instead of Serial.println(Motion); you should do Serial.println(digitalRead(Motion)); instead.

[13LenD]

Thanks!

[13LenD]

Sorry, to come back to this! What are the reasons that you should use digitalread here? Normally this isn't necessary, is it? Is this due to the type of bootloader?

[MCUdude]

Because Serial.println(Motion); will only print the value Motion holds (16), while Serial.println(digitalRead(Motion)); will read the value of pin Motion (16). This isn't MiniCore spesific, but applies for all Arduino boards.

[13LenD]

Thanks for your explanation. Learned something again!