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**clintfan** · 01-19-2005, 12:10 AM

Good question. Don't know if a stock sensor is available. I couldn't easily find one on the web. If Asus sells one it's certainly not obvious ... however they do sell stuff that isn't on their website --like BIOS chips-- but you have to call them to find out about it.

The Winbond chip seems to want one of 3 possible things, but exactly what it wants has already been preprogrammed into the Asus BIOS and we have no idea which of the 3 modes has been programmed for the register bits driving that TRPWR1 port. Whichever way they went, one side of the sensing device is grounded, so that doesn't provide a clue.

If it's been programmed to take a thermistor, the properties are a beta value of 3435K with a resistance of 10K ohms at 25 deg. C.

If instead it's been programmed to use a thermal diode, there's a couple options: the Winbond chip has a bit to switch between thermistor or diode. But if it's in diode mode, then there's a second bit to switch between wither an actual diode, or a 2N3904 transistor with B-C tied together to act as a thermal diode. You might need to chase the signal traces on the mobo to figure out which circuit they've set up, then consult the Winbond datasheet section 5.3.3.2 for more clues.

I think if you want to be successful with this project, I suggest you phone Asus support, and ask if they intended a thermistor or a diode to be attached to this port. The quoted "thermal sensor cable" is definitely not specific- enough information for your needs. From what I hear you might get quicker turnaround --or at least some answer-- if you choose the phone over an email that might get lost in the pileup. Who knows.. they might even sell you a sensor!

Hope this helps,

-clintfan

01-19-2005, 12:10 AM	#2 (permalink)
clintfan Guru Join Date: Sep 2003 Location: Silicon Valley, CA Posts: 2,655 OS: XP Pro	Good question. Don't know if a stock sensor is available. I couldn't easily find one on the web. If Asus sells one it's certainly not obvious ... however they do sell stuff that isn't on their website --like BIOS chips-- but you have to call them to find out about it. The Winbond chip seems to want one of 3 possible things, but exactly what it wants has already been preprogrammed into the Asus BIOS and we have no idea which of the 3 modes has been programmed for the register bits driving that TRPWR1 port. Whichever way they went, one side of the sensing device is grounded, so that doesn't provide a clue. If it's been programmed to take a thermistor, the properties are a beta value of 3435K with a resistance of 10K ohms at 25 deg. C. If instead it's been programmed to use a thermal diode, there's a couple options: the Winbond chip has a bit to switch between thermistor or diode. But if it's in diode mode, then there's a second bit to switch between wither an actual diode, or a 2N3904 transistor with B-C tied together to act as a thermal diode. You might need to chase the signal traces on the mobo to figure out which circuit they've set up, then consult the Winbond datasheet section 5.3.3.2 for more clues. I think if you want to be successful with this project, I suggest you phone Asus support, and ask if they intended a thermistor or a diode to be attached to this port. The quoted "thermal sensor cable" is definitely not specific- enough information for your needs. From what I hear you might get quicker turnaround --or at least some answer-- if you choose the phone over an email that might get lost in the pileup. Who knows.. they might even sell you a sensor! Hope this helps, -clintfan Last edited by clintfan; 01-19-2005 at 12:13 AM.