volatile uint16_t overflows = 0;
volatile bool isPressed = false;

void Count() {
  isPressed = true;
}

void Pause() {
 
  if(isPressed){
      isPressed = false;
      Serial.print("Tempo: ");
      Serial.print(overflows);
      Serial.println(" ms");
  }
}

// This function will be called every time TIMER2 overflows
// and it is binded to Timer2 Overflow Interrupt Service Routine
ISR(TIMER2_OVF_vect) {
    overflows ++;
}

void setup() {
    Serial.begin(9600);

    // Set pin 13 as output
    pinMode(13, OUTPUT);
    // Set pin 2 as input
    pinMode(2, INPUT);
    // Set pin 1 as input
    pinMode(3, INPUT);

    attachInterrupt(
        digitalPinToInterrupt(2), Count, RISING
    );
    attachInterrupt(
        digitalPinToInterrupt(3), Pause, RISING
    );
    
    TCCR2A = 0b00000000; // normal operation mode
    TCCR2B = 0b00000100; // enabling 64 prescaler
    // Clock = 250000Hz
    // 1/250000 = 0.000004
    // 0.000004 * 256 = 0.001024, more or less 1 milisecond
    // Enable TIMER2 overflow interrupt.
    TIMSK2 = TIMSK2 | 0b00000001;

    // enable global interrupts
    sei();
}

void loop() {
  if (!isPressed) {
      overflows = 0;
      // Clear Timer2 counter
      TCNT2 = 0;
      digitalWrite(13, LOW);
  }
  else {
    digitalWrite(13, HIGH);
  }
}