def hardware_reference(device='K300'):
    """Print useful hardware information about the device

    Displays hardware information about the DIO device, such as pinouts.
    Then pinouts assume that the user is facing the front if the device, and that the fins
    are pointed up.

    Args:
        device (str, optional): The karbon series being used. Defaults to the K300
    """
    ref_k300 = """
    Info: Isolated digital input/ouput. To function properly, dio should be connect to
    external power and grund.

    Pinout: || GND | DO_1 | DO_2 | DO_3 | DO_4 | DI_1 | DI_2 | DI_3 | DI_4 | PWR ||
        """
    ref_dict = {'K300': ref_k300}
    try:
        print(ref_dict[device.upper()])
    except KeyError:
        print('Please select from: [K300]')
