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    SubjectRe: W1: w1_slave units, standardize 1C or .001C? Break API
    David Fries wrote:
    > On Mon, Jan 21, 2008 at 07:11:07PM -0800, H. Peter Anvin wrote:
    >> H. Peter Anvin wrote:
    >>> Millikelvins would have the nice property of never being negative. :)
    > True, but the sensor returns the value as a signed integer in C. That
    > is where the earlier negative number problem was, it would have to do
    > yet another conversion to go to Kelvin, and it would be just one more
    > potential for error. Everyone knows that a bad conversion doomed at
    > least one space craft, let's stick to Centigrade.

    Uhm... the conversion is exact as long as you have at least centikelvin
    precision (0 °C = 273.15 K by definition, and the multiplier is 1.)

    >> Alternatively, centikelvins would fit nicely in 16 bits if anyone cares...
    >> 655.35 K = 382.20 °C = 719.96 °F
    > The range for the sensor is -55 to 125 C, if an application didn't
    > care about precision they could store it in a signed 8 bit value just
    > fine.

    This was more a comment as to it possibly being a convenient format for
    more than this particular sensor.

    The nice thing with kelvins is no need to worry about negative numbers
    and something misparsing them, that's all.

    I certainly did not imply that we should even consider use °F. That's
    obviously ridiculous.


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