convert two bytes from DS18B20 temperature reading register into usable temperature

ds18b20.py

def ds18b20_convert(lsb, msb):
    """
    Converts the 16-bit sign-extended two’s complement number, stored
    in the DS18B20's temperature register, into a temperature.
    """
    reading = lsb + (msb << 8)
    inv = reading & 0x8000
    if inv: # two's compliment
        reading = (reading ^ 0xffff) + 1
    val = reading / 16.0
    return inv and -val or val

works for default 12 bit resolution, not so sure about 11, 10, and 9 bit resolution settings…