#define LED_OVRFLW 8
#define OpticalSensorPin 2
uint64_t triggerTime = 0;


void isr() {
  static bool busy = false;
  uint64_t oldTriggerTime = triggerTime;
  triggerTime = micros();
  if(busy) {
    digitalWrite(LED_OVRFLW, 1); // allumer la LED de saturation
  }
  else {
    busy = true;
    digitalWrite(LED_BUILTIN, 1); // Plus on roule vite, plus la LED brille car temps "OFF" diminue
    uint64_t dt = triggerTime - oldTriggerTime;
    sei();         // dt has been stored, ISR can now be interrupted
    Serial.println((uint32_t)dt);
    Serial.flush();
    digitalWrite(LED_BUILTIN, 0); // éteindre la LED
    busy = false;
  }
}  // end of TIMER2_COMPA_vect

void setup()
{
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(OpticalSensorPin, INPUT_PULLUP);
  pinMode(LED_OVRFLW, OUTPUT);
  digitalWrite(LED_BUILTIN, 0);
  digitalWrite(LED_OVRFLW, 1);

  while(!Serial)
  {
    ;  // wait for serial port to connect. Needed for native USB port only
  }
  
  attachInterrupt(digitalPinToInterrupt(OpticalSensorPin), isr, RISING);
  Serial.println("Time_between_pulses_V1");
  Serial.flush();
  digitalWrite(LED_OVRFLW, 0);
} // end of setup

void loop()
{
} //end of loop