Materials: Romu board, USB cable (if needed for debugging, although the board is USB-A), open serial terminal. 2. Button identification: The Romu board integrates a physical button intended for debugging or user input. As with the LED, this button is connected to a specific internal pin. Consult the datasheet to identify the associated GPIO (often a debug pad). 3. Code configuration: In MicroPython, import 'machine'. Create a Pin object for the button in input mode with pull-up resistor (e.g., btn = machine.Pin(23, machine.Pin.IN, machine.Pin.PULL_UP)). PULL_UP mode is crucial as the button usually connects the pin to ground when pressed. 4. Reading loop: Write a 'while True' loop that reads the button state with 'btn.value()'. 5. Display: Add a 'print()' in the loop to display the state (1 for released, 0 for pressed) or use a condition to print 'Button pressed' only on state change. 6. Testing and debugging: Upload the code. Open the serial monitor. Physically press the button on the board. You should see the corresponding messages appear in the terminal. This step confirms that internal inputs are accessible and functional, essential for custom HID devices.