Barometric pressure setting

    Args:
        msg (String): 28 bytes hexadecimal message (BDS40) string

    Returns:
        float: pressure in millibar

def p40baro(msg):
    """Barometric pressure setting

    Args:
        msg (String): 28 bytes hexadecimal message (BDS40) string

    Returns:
        float: pressure in millibar
    """
    d = hex2bin(data(msg))

    if d[26] == '0':
        return None

    p = bin2int(d[27:39]) * 0.1 + 800    # millibar
    return p