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Intel Thermal sensor

Hello folks, it's me again.
I need to gain acces to any thermal sensor that my CPU can provide to
me. Now:
1. I'm a veeery veeery beginner programmer;
2. I've got only some fair knowledge on how CPU's system registers
works.
3. My English is bad and full of mistakes.

Somewhere I've read that an Intel's CPU can have one, two, or maybe
more thermal sensor: what I need is to learn how to query the CPU for
retrieve any information about thermal state of her.
All of this because I'll like to monitor CPU's temperature.
Let me summarize:
1. Supposing that we have an Intel-like CPU that support CPUID
instruction,
2. Supposing that we have one thermal sensor shipped in the PC,
3. Supposing that I know only a few ASM's instructions:
How can I retrieve infos about CPU's temperature having only a bunch
of Intel's manuals and an old Pentium3-based computer?
Saludos amigos!

0
Ne_Propheta
6/17/2008 9:09:27 AM
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Ne_Propheta told us:

> I need to gain acces to any thermal sensor that my CPU can provide to
> me. Now:
> 1. I'm a veeery veeery beginner programmer;
> 2. I've got only some fair knowledge on how CPU's system registers
> works.
> 3. My English is bad and full of mistakes.

I think this NG have more natitive non-US-english speaking
folks than any US-court may ever have counted.

I'm guilty on that one for sure :)
 my native language is Viennese {aka: Meidlinger Fat 'L' speach}
(anyway an indo-german-dialect is totally far away from German)

> Somewhere I've read that an Intel's CPU can have one, two, or maybe
> more thermal sensor: what I need is to learn how to query the CPU for
> retrieve any information about thermal state of her.
> All of this because I'll like to monitor CPU's temperature.

It's not the CPU which sensors the evironment temperature,
a CPU can only tell that "it's hot in here" and so reduce the
chipset's congfiguration main clock rate for a certain time period.

If this wont help within time then a CPU would either shutdown
or switch itself into a low power idle/sleep mode.

<quote>
> Let me summarize:
> 1. Supposing that we have an Intel-like CPU that support CPUID
> instruction,
> 2. Supposing that we have one thermal sensor shipped in the PC,
> 3. Supposing that I know only a few ASM's instructions:
</>

The CPU will give a fart on your attempt to override thermal limits
even it may slow down if you don't 'clean up the fans' regularely.
I do this every three month, and for sure not just in case ...

<quote>
As long you assumtions fit reality, the above may work...
</>
> How can I retrieve infos about CPU's temperature having only a bunch
> of Intel's manuals and an old Pentium3-based computer?
> Saludos amigos!

In return: my kind and respectful Salutes to all Friends of Logic :)

Not all CPU-BIOS-functions may show the current environment temperature.
Most BIOS just let us die as stupid as we came  ... :)
Older BIOS/CPUs may not even aware of the environment temerature...

In rare (CPU+HW-dependant) environments we can get this info,
but it depends on the ability (if at all friendly and open)
on the BIOS to even see what's going on behind our neck.

__
wolfgang


0
Wolfgang
6/17/2008 9:30:22 PM
So we have to gain access to something like BIOS service directory,
issuing a specifically designed interrupt to him and watch the
results?
Can't we access some CPU registers scrambling the whole system just
for fun? :)
Jokes apart, thermal informations are keeped somewhere into the RAM?
'morning,
Ne_Prpht

0
Ne_Propheta
6/19/2008 8:39:22 AM
I think the CPU heat sensor is on the CPU sub-board under the CPU;
there's something there that sticks up at an angle to be "springy" and
touch the chip. If that is what it is and this this fires then the
local clocking circuitry which is is that area might very well will
bring the clock speed down.
I strongly doubt there a control from the CPU, but there might be an
input signal line that the cpu checks as part of th diagnostic (all
guessing).

0
Terence
6/19/2008 10:58:29 AM
In article <9688f369-2135-4a7f-9112-dc3660827782
@t54g2000hsg.googlegroups.com>, spamtrap@crayne.org says...
> So we have to gain access to something like BIOS service directory,
> issuing a specifically designed interrupt to him and watch the
> results?
> Can't we access some CPU registers scrambling the whole system just
> for fun? :)
> Jokes apart, thermal informations are keeped somewhere into the RAM?
> 'morning,
> Ne_Prpht

The thermal sensors are normally accessed through the system management 
bus (SMBus), not as CPU registers. Searching for SMBus might get you 
some relevant information. 

-- 
    Later,
    Jerry.

The universe is a figment of its own imagination.

0
Jerry
6/19/2008 6:32:39 PM
On Jun 19, 8:32�pm, Jerry Coffin  <spamt...@crayne.org> wrote:
> In article <9688f369-2135-4a7f-9112-dc3660827782
> @t54g2000hsg.googlegroups.com>, spamt...@crayne.org says...
>
> > So we have to gain access to something like BIOS service directory,
> > issuing a specifically designed interrupt to him and watch the
> > results?
> > Can't we access some CPU registers scrambling the whole system just
> > for fun? :)
> > Jokes apart, thermal informations are keeped somewhere into the RAM?
> > 'morning,
> > Ne_Prpht
>
> The thermal sensors are normally accessed through the system management
> bus (SMBus), not as CPU registers. Searching for SMBus might get you
> some relevant information.
>
> --
> � � Later,
> � � Jerry.
>
> The universe is a figment of its own imagination.

Ok, I'll try.
Thanks!

0
Ne_Propheta
6/20/2008 1:24:20 PM
On 19 Jun., 20:32, Jerry Coffin  <spamt...@crayne.org> wrote:
> The thermal sensors are normally accessed through the system management
> bus (SMBus), not as CPU registers. Searching for SMBus might get you
> some relevant information.

But how many different Winbond-Monitoring IC exist?

For my Epox 8k3A+(KT333) i use the W83783S Data Sheet(w83783s.pdf).

Dirk

0
Dirk
6/23/2008 6:29:58 AM
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