Readability in creation of a long output string
How about something like this:

def read_config(bus, sensor):
    tpl = '''Status of DS1621 at address {sensor}:
    \tConversion is {done}
    \t{have_th} measured {th} degrees Celsius or more
    \t{have_tl} measured below {tl} degrees Celsius
    \tNon-volatile memory is {busy}'''

    print tpl.format(sensor=sensor,
                     done='done' if Conf &amp; DONE else 'in process',
                     have_th='HAVE' if Conf &amp; TH_BIT else 'have NOT',
                     th=TH,
                     have_tl='HAVE' if Conf &amp; TL_BIT else 'have NOT',
                     tl=TL,
                     busy='BUSY' if Conf &amp; NVB else 'not busy',
                     )


This is PEP8 compliant, and I think more readable.

Also, I think there's nothing wrong with this kind of use:

'something' if condition else 'otherthing'