volatile uint32_t count = 0;  // Holds the count of interrupts

void incrementCount() {
  count++;
}

void setup() {
  Serial.begin(115200);

  pinMode(2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), incrementCount, RISING);
}

void loop() {
  Serial.print("Interrupt count: ");
  noInterrupts();
  Serial.println(count);
  interrupts();
  delay(100);
}