From: David Fries <david@fries.net>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: W1: w1_slave units, standardize 1C or .001C? Break API
Date: Tue, 22 Jan 2008 22:09:37 -0600 [thread overview]
Message-ID: <20080123040937.GB4025@spacedout.fries.net> (raw)
In-Reply-To: <47955ECB.3050100@zytor.com>
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.
> 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.
--
David Fries <david@fries.net>
http://fries.net/~david/ (PGP encryption key available)
next prev parent reply other threads:[~2008-01-23 4:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-21 23:15 David Fries
2008-01-22 1:08 ` H. Peter Anvin
2008-01-22 3:11 ` H. Peter Anvin
2008-01-22 21:07 ` Evgeniy Polyakov
2008-01-22 21:12 ` Evgeniy Polyakov
2008-01-23 4:09 ` David Fries [this message]
2008-01-23 4:22 ` H. Peter Anvin
2008-01-22 21:06 ` Evgeniy Polyakov
2008-01-23 4:00 David Fries
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