Very basic rotary encoder support for Empyrean

EmpyreanEncoder.ino

constexpr uint8_t encoder_pin_a = 5;
constexpr uint8_t encoder_pin_b = 6;

int16_t count = 0;
bool prev_b = false;
bool change = false;

void ISRENCA()
{
  static bool prev_read = false;
  
  if(prev_b)
  {
    count--;
    change = true;
  }
  else
  {
    count++;
    change = true;
  }
}

void ISRENCB()
{
  prev_b = !prev_b;
}

void setup()
{
  // Set pin modes
  pinMode(encoder_pin_a, INPUT_PULLUP);
  pinMode(encoder_pin_b, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(encoder_pin_a), ISRENCA, RISING);
  attachInterrupt(digitalPinToInterrupt(encoder_pin_b), ISRENCB, CHANGE);
  prev_b = digitalRead(encoder_pin_b);
  // Serial
  SerialUSB.begin(115200);
  while(!SerialUSB);
  SerialUSB.println("Encoder demo");
}

void loop()
{
  if(change)
  {
    SerialUSB.println(count);
    change = false;
  }
}