// ============================================================
  // Seeed XIAO SAMD21 - Tact Switch + LED
  // Press the button to turn on the LED
  // ============================================================

  const int buttonPin = 1;  // D1 - tact switch input pin
  const int ledPin    = 7;  // D7 - LED output pin

  void setup() {
    // Set button pin as input with internal pull-up resistor
    // When button is not pressed: pin reads HIGH
    // When button is pressed:     pin reads LOW
    pinMode(buttonPin, INPUT_PULLUP);

    // Set LED pin as output
    pinMode(ledPin, OUTPUT);
  }

  void loop() {
    // Read the current state of the button
    int buttonState = digitalRead(buttonPin);

    if (buttonState == LOW) {
      // Button is pressed → turn LED on
      digitalWrite(ledPin, HIGH);
    } else {
      // Button is released → turn LED off
      digitalWrite(ledPin, LOW);
    }
  }