ALi M5879 info

dandrea2 · 06-27-2003, 04:22 PM

I've got a question and was wondering if anyone here might be able to answer this.

I've been wanting to set up my system to read the CPU temp from the on-die diode of my AthlonXP 1700+ chip (TBred B core), but would rather try to simplify things and not have to build an extra board for the circuit if possible.

So to this end I did a little looking around and found out something interesting. My motherboard is an IWill XP333 (rev 2.1 I think, will have to check) that has the M5879 hardware monitor chip on it. According to ALi's web site, that chip has two temp inputs, one of which can do either a thermister or a diode. What I would like to do is change it so the CPU temp doesn't read the thermister under the CPU anymore, but read it from the CPU's diode.

I put in a request to ALi for a datasheet, but haven't heard anything yet after a couple days.

Does anyone here have any info related to this? Or maybe even info on someone actually trying this? :-)

dandrea2 · 06-28-2003, 05:09 PM

So, has anyone tried this? Or have any info at all?

Groth · 06-28-2003, 06:06 PM

That's how I did my first thermal diode reading. I eliminated the system thermistor attached to a Winbond w83697hf, swapped a resistor, added a cap, and ran wires to the back of the socket. Interestingly, the BIOS interpretted the temperature correctly, where as MBM need to be told that it was now a diode.

But, without that datasheet, you are screwed. You need to be able to identify the correct IC pins. You need to know what kind of circuit the IC can read.

It will be faster and easier to add the popular LM90 from National Semiconductor ($3 from Digikey). No board needed, just use a couple pieces of electrical tape to attach it to (and insulate it from) the back of your motherboard. Run six wires and you're done.

dandrea2 · 06-28-2003, 11:04 PM

Well, I haven't heard from ALi yet, so I may have to go with the extra chip. What I was really hoping I wouldn't have to do was to have a whole bunch of wires all over the place (yeah, I know it's only 6, but).

As it is I can wait. I may also try contacting Alexander van Kaam (MBM author) to see if he can relay some info to me. All I really need to know is if there are any changes I need to make to the motherboard circuitry (like you had to change a resistor and such) to make the chip work correctly against a diode input. What would be nice is if it's automatic. :-)

06-27-2003, 04:22 PM	#1
dandrea2 Cooling Neophyte Join Date: May 2003 Location: Leavenworth, KS Posts: 3	ALi M5879 info I've got a question and was wondering if anyone here might be able to answer this. I've been wanting to set up my system to read the CPU temp from the on-die diode of my AthlonXP 1700+ chip (TBred B core), but would rather try to simplify things and not have to build an extra board for the circuit if possible. So to this end I did a little looking around and found out something interesting. My motherboard is an IWill XP333 (rev 2.1 I think, will have to check) that has the M5879 hardware monitor chip on it. According to ALi's web site, that chip has two temp inputs, one of which can do either a thermister or a diode. What I would like to do is change it so the CPU temp doesn't read the thermister under the CPU anymore, but read it from the CPU's diode. I put in a request to ALi for a datasheet, but haven't heard anything yet after a couple days. Does anyone here have any info related to this? Or maybe even info on someone actually trying this? :-)

06-28-2003, 05:09 PM	#2
dandrea2 Cooling Neophyte Join Date: May 2003 Location: Leavenworth, KS Posts: 3	So, has anyone tried this? Or have any info at all?

06-28-2003, 06:06 PM	#3
Groth Cooling Savant Join Date: Mar 2003 Location: MO Posts: 781	That's how I did my first thermal diode reading. I eliminated the system thermistor attached to a Winbond w83697hf, swapped a resistor, added a cap, and ran wires to the back of the socket. Interestingly, the BIOS interpretted the temperature correctly, where as MBM need to be told that it was now a diode. But, without that datasheet, you are screwed. You need to be able to identify the correct IC pins. You need to know what kind of circuit the IC can read. It will be faster and easier to add the popular LM90 from National Semiconductor ($3 from Digikey). No board needed, just use a couple pieces of electrical tape to attach it to (and insulate it from) the back of your motherboard. Run six wires and you're done.

06-28-2003, 11:04 PM	#4
dandrea2 Cooling Neophyte Join Date: May 2003 Location: Leavenworth, KS Posts: 3	Well, I haven't heard from ALi yet, so I may have to go with the extra chip. What I was really hoping I wouldn't have to do was to have a whole bunch of wires all over the place (yeah, I know it's only 6, but). As it is I can wait. I may also try contacting Alexander van Kaam (MBM author) to see if he can relay some info to me. All I really need to know is if there are any changes I need to make to the motherboard circuitry (like you had to change a resistor and such) to make the chip work correctly against a diode input. What would be nice is if it's automatic. :-)

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