// const byte LED = 13;
// const byte BUTTON = 2;

// Interrupt Service Routine (ISR)
// void switchPressed()
// {
//     if (digitalRead(BUTTON) == HIGH)
//         digitalWrite(LED, HIGH);
//     else
//         digitalWrite(LED, LOW);
// }

// void setup()
// {
//     pinMode(LED, OUTPUT);                                                  // so we can update the LED
//     digitalWrite(BUTTON, HIGH);                                            // internal pull-up resistor  **** Focus On This ****
//     attachInterrupt(digitalPinToInterrupt(BUTTON), switchPressed, CHANGE); // attach interrupt handler
// }

// void loop()
// {
//     // loop doing nothing
// }

long OldTimeOfGreenLED = 0;
long TimeToBlinkGreenLED = 300;
volatile bool StatusOfRedLED = false;
bool StatusOfGreenLED = false;

void setup()
{
  // Testing How To Make A Pin Mode Of A Pin With INPUT_PULLUP By Using pinMode(pin, mode)
  // And Without Using It

  // pinMode(2, INPUT_PULLUP);
  // digitalWrite(2, HIGH);

  // Testing How To Disable All INPUT_PULLUP Pins By PUD Bit In MCUCR

  // MCUCR |= 1 << 4;

  pinMode(4, OUTPUT);
  pinMode(3, OUTPUT);

  PORTD |= 1 << 2;
  EIMSK |= 1;
  SREG |= 1 << 7;


  // attachInterrupt(digitalPinToInterrupt(2), ReverseLEDStatus, RISING);

  // Not recommended to use this syntax  (Typing the interrupt number directly without using digitalPinToInterrupt() function )
  // because it May will raise another interrupt in different board

  // attachInterrupt(2, ReverseLEDStatus, RISING);
}

// void ReverseLEDStatus()
// {
//     StatusOfRedLED = !StatusOfRedLED;
//     digitalWrite(3, StatusOfRedLED);
// }

void loop()
{
  // Pin Number 4
  if (millis() - OldTimeOfGreenLED > TimeToBlinkGreenLED)
  {
    digitalWrite(4, StatusOfGreenLED);
    StatusOfGreenLED = !StatusOfGreenLED;
    OldTimeOfGreenLED = millis();
  }
}

// Debouncing Not Completed Yet 

ISR(INT0_vect)
{
  StatusOfRedLED = !StatusOfRedLED;
  digitalWrite(3, StatusOfRedLED);
}