8K5A2+ temp. diode, expert question

[dpr]

Hi,

I know that the EPoX 8K5A2+ uses the Attansic ATTP1 chip to monitor the temperature with the help of the internal diode of the CPU.

It's a nice overheat protection but the latest BIOS version (08-15-02) doesn't show the data of the internal diode. "PC Health" simply shows the completely useless temp. of the external thermistor.

However, it should be possible to read out the values the internal diode provides if we would have more information about the Attansic chip (registers/addresses ...)
So my question is, if someone out there knows more about this chip on the 8K5A2+ board.
I don't think that EPoX would give me such kind of information

DPR

[dpr]

Originally posted by EPoX Tech


It doesn't.

Sorry, but I have to contradict ...

the diode-pin of the processor is definitely connected to the Attansic and the data-sheet of the chip clearly says that it is an"over-temperature protection device".

Regards,

DPR

[EPoX Tech]

Scrub - two posts - many apologies - after reading your first post properley with my English reading head on I now understand entirely what you are saying

[cs25]

So what does it mean? Is the temperature readout accurate or not?

[dpr]

Originally posted by cs25
So what does it mean? Is the temperature readout accurate or not?

The temperature shown in the BIOS (or in any other program like MBM) is not accurate at all !
Whereas the Attansic chip monitors the "real" CPU temp. (EPoX affirmed this) and sends a shutdown signal if the temp. reachs 100°C ...

DPR

[dpr]

I've got some bad news

It will NEVER be possible to read out the temperature of the internal diode with the 8K5A2+ !!! And there never will be a BIOS version which is able to show the correct values ...

This information comes directly from the EPoX support (which by the way is really one of the best I've ever seen) ...

DPR

[Folsom]

I got some more bad news: it will be very hard to hack in a Maxim/Analog Devices temp IC because to use the ATTP1 IC you need to ground the D- pin. The Maxim and Analog devices parts need D- ungrounded.

I asked Attansic about the ATTP1, and they sent me the datasheet and a reference schematic. There is only one pin connected to the socket (D+).

I haven't checked to see where the D- is grounded, but I suspect it would be on an inner layer.

[dpr]

First of all: thanks for your answer.

I wonder you got the sheet from Attansic. I know a lot of people (including myself) who asked for the datasheet and even didn't get any answer.
Which datasheet do you have ? I've got the very short "ATTP1_1.0_web.pdf" Revision 1.0 (April 2002) ...

Do you know more about the external resister with which it is possible to set the trigger temperature ?

DPR

P.S.: Nice to see another expert in this forum

[Folsom]

I just sent an email to Attansic, and they gave me the datasheet and an application schematic. The part reads the diode, and when the temperature rises above a certain level (set by resistors), it pulls down on the PS_ON line, shutting off the supplies. After that, it releases PS_ON after 5VSB is removed or the power button is pressed.

I had a MAX6657 connected to the SMBus, and then I saw the connections to the D+ pin. I traced the pin back to the ATTP1, and I realized it had a hardware over temp circuit. I need to find a way to unground D-.

Enclosed is the application schematic.

[dpr]

Originally posted by Folsom
I just sent an email to Attansic, and they gave me the datasheet and an application schematic. The part reads the diode, and when the temperature rises above a certain level (set by resistors), it pulls down on the PS_ON line, shutting off the supplies. After that, it releases PS_ON after 5VSB is removed or the power button is pressed.

I had a MAX6657 connected to the SMBus, and then I saw the connections to the D+ pin. I traced the pin back to the ATTP1, and I realized it had a hardware over temp circuit. I need to find a way to unground D-.

Enclosed is the application schematic.

I knew these things about the shutdown procedure ... the other datasheet contains all information about it.

Do you know what is written on the GND D- is connected to (in the sheet) ??? My chinese is not that good
However - I don't know much about the MAX. You have to connect D- to DXN, right ? What kind of output do we have on D- (constant voltage?) ? So isn't it possible to connect DXN to GND or to a constant voltage source ?

Sounds like a nice construction you're trying to create - if you're successful then it would be nice if you could send me an image of it !

DPR