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Message
From: "Renaux Jacky" <renaux.jacky@w...>
Date: Wed, 22 Oct 2003 14:03:16 +0200
Subject: RE: [oc] Basic FPGA question (OT)
Hi
You must careffully sets the value since
the frequency
is based on :
base_feq - 10% * ( actual_temp -
starting_tmp )
starting_tmp = ambiant temp when you power
up
base_freq = frequency on starting frequency
based on
silicon speed grade and ambiant
temp
actual _temp = ambiant + silicon temp (
silicon activity )
the counter frequency slow down as the
silicon temp increase
then it is a silicon thermometrer but you
must first set up
the starting value
for fan control it might cost less to use a
single diode
and or the diode included into the xilinx
virtex family
(It was the case few years ago)
jacky
-----Message d'origine-----
De : owner-cores@o...
[mailto:owner-cores@o...]De la
part de Kirill 'Big K' Katsnelson
Envoyé : mercredi 22 octobre 2003 1111
À : cores@o...
Objet : RE: [oc] Basic FPGA question (OT)
Some time ago, Renaux Jacky wrote...
>that counter
>frequency will be proportionnal to the
>silicon temperature ( silicon timing is
>quite close
>to 10% every 10 degres ----) . for a
>given device your counter will be a
silicon
>thermometer
Is this "thermometer" practically usable
for fan speed control in a
forced-cooling system? It reports the
temperature right on the spot.
Nice idea anyhow! :)
-kkm
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