const byte pin_LED=13;
const byte pin_Btn=2;
void ISRbtn2();
volatile byte ledstate=LOW;
void setup() {
  pinMode(pin_Btn, INPUT_PULLUP);
  pinMode(pin_LED, OUTPUT);
  attachInterrupt(digitalPinToInterrupt(pin_Btn), ISRbtn2, RISING);
ledstate=HIGH;
}

void loop() {
  digitalWrite(pin_LED, ledstate);
  while (1)
  { // quelque chose
    }
}


void ISRbtn2() {
  ledstate=!ledstate;
    digitalWrite(pin_LED, ledstate);

}