def pwd(raw_value, unit=None):
    """Pulse Width Modulator (PWM) output.

    The register is a 16-bit word as usual, but the module does not use the 5 LSBs.
    So, 10-bit resolution on the PWM value (MSB is for sign and is fixed).
    0-100% duty cycle maps to 0 to 32736 decimal value in the register.

    ``PWD = 100 * raw_value / (2**15 - 1)``


    """

    return (100 * float(raw_value) / (2 ** 15 - 1), unit)