NF7-S CPU Thermal Diode Mod

[Gizmo]

As you probably already know, the NF7-S uses a socket thermistor to get the temperature readings that are reported by utilities such as MBM and 8rdavcore. There have been several times that I wanted to know what the actual temp as reported by the CPU thermal diode was, and the NF7-S doesn't have any way to get this information. This, in fact, was one of the things that I found attractive about the AN-7.

The NF7-S uses an Attansic ATTP1 Over Temperature Protection IC to monitor the temperature of the CPU using the thermal diode. This chip has NO other hardware interface, so there is no way to read this chip to get the current CPU temp. It also controls the system power-on line. This enables it to kill system power when it detects an over-temperature condition on the CPU. There is no way to change the shutdown temperature programmaticaly. This is set via a resistor network on the board.

The NF7-S also has the previously mentioned socket thermistor. This is monitored by channel 2 of the Winbond chip, and is what provides the temperature reported by MBM, the BIOS, and anything else that reports the CPU temp.

The Winbond chip has three channels that are capable of monitoring temperature. Of these, channel 1 monitors a temp sensor on the mobo, channel 2 monitors the CPU socket thermistor, and channel three monitors..............well, as far as I can tell, it monitors nothing.

So, what we do is disconnect the CPU diode from the Attansic chip and connect it to channel 3 of the Winbond chip. Note, doing this removes our hardware-based OTP shutdown of the system. We still have the OTP shutdown that is programmed into the Winbond chip (set by the CPU OTP setting in the BIOS), but that only helps us if the system is capable of POSTing.

So, here's how to do the mod:

1) Lift Pin 4 of the Attansic OTP chip which is located in the center of the CPU socket.

2) Lift Pin 102 of the Winbond 83627 chip which is located near the DIMM sockets. WARNING! THIS PIN IS EXTEMELY DELICATE!

3) Cut a length of wire (I used Kynar 32 guage wire-wrap wire from Radio Shack) about 8 cm (3") long. Route this wire between the cpu socket pins and between the mobo and the socket into the center area of the CPU socket. Hint: this is easier to do if you run the wire diagonally between the pins, as they line up in nice little rows on the diagonal.

4) If you follow the trace from the pad of pin 4, you will see that it goes to a resistor (a little black thing with the numbers 103 on it) and a capacitor (a little brown thing next to the resistor). Solder one end of the wire to the junction of the resistor and capacitor.

5) Solder the other end of the wire directly to pin 102 of the Winbond chip. WARNING! THIS PIN IS EXTREMELY DELICATE!

6) Take a bit of super glue and glue the wire down near the Winbond chip so that it can't flop about and break off the pin. If this pin breaks, you are gonna have a really, REALLY hard time reattaching the wire.

7) Take another length of wire 1 cm (about 1/2") long, and solder it from pin 4 of the Attansic chip to pin 5 of the same chip.

Boot the machine. If it comes up, odds are you are golden. If you get a two-tone siren, you've mucked something up and need to double-check everything you just did.

If the machine comes up, go into Windows and run MBM. You will need to configure MBM to monitor channel 3 of the Winbond chip as a Winbond Diode input. On my board, it was not necessary for me to configure MBM for an offset, as the temps reported seemed to agree very closely with what I got from the same CPU on my AN-7.

Sorry that I couldn't give you better pictures. Note that the picture of the socket wiring shows me connecting pins 4 and 7 of the Attansic chip. This works, but connecting pins 4 and 5 is a better solution, because pin 5 is attached to an RC network.

[Aedan]

Originally Posted by gizmo

We still have the OTP shutdown that is programmed into the Winbond chip (set by the CPU OTP setting in the BIOS), but that only helps us if the system is capable of POSTing.

I've never been able to get the Winbond OTP to shut a machine down when the CPU exceeds the temperature set.

[Gizmo]

My NF7-S shuts down when it gets to whatever temp I set in the BIOS. Since the set point on the ATTP1 is controlled by a resistor network that is not, as far as I can tell, controlled in any way by any external circuitry, and the ATTP1 has no interface circuitry for talking to other stuff, and the Winbond chip has an OTP function built in, I figured it was the Winbond chip doing it. I don' suppose there is a law requiring it to be that way, though.

[Lord Vetinari]

Interesting mod- anyone think it can be done on an 8RDA+?
At least the attansic chip is abit more accessible.

EDIT- ah just checked- not quite the same Attansic chip.

[Gizmo]

Originally Posted by Lord Vetinari

Interesting mod- anyone think it can be done on an 8RDA+?
At least the attansic chip is abit more accessible.

EDIT- ah just checked- not quite the same Attansic chip.

Which chip is it? So far I'm two for two on walking people through mods to boards that I don't know anything about (two aborted tries). I'm hoping to change that.

[Lord Vetinari]

Its an ATXP1- has 48 legs
;-http://www.attansic.com.tw/english/products/pdf/atxp1.pdf

Funny thing is it does not say anything about cpu thermal protection, wonder if there is another attansic chip in the same place as yours? (fraid too much like hard work to take my CPU out)

[Gizmo]

The ATXP1 is a jumper-free over-clock controller. It's job is to fake the VReg and clock gen circuitry. It doesn't do any OVP or OTP functions.

The ATTP1 will most likely be located directly under the socket or somewhere near it, if the board uses hardware based thermal diode protection at all.

Oddly enough, if the thermal diode on the chip isn't used now, it might actually be an easier mod to do than mine.

[Lord Vetinari]

Think you're right- found this:-http://faq.ixbt.com/_mobo/epox8rda.shtml
Think it is the mod I'm looking for- anyone speak russian?

[Aedan]

On my 8RDA+ board (rev 1.1), the ATTP1 is right next to the CPU socket. It's next to the release arm on the socket! It's only 8 pin remember.

[waifaq]

gizmo : Thankz for the guide. I connect Pin 4 & 5 Attansic ATTP1 working great.

I got some questions here.

Is there any difference in reading temp, connecting Pin 4 & 7 vs. Pin 4 & 5 Attansic ATTP1 ?

My MBM5 v5.3.6.0 give weird reading. Sometimes reading will go as low -1°C for Winbond 2 & Winbond 3 Diode.

I don't think is possible to reach -1°C, since I'm on air cooling. Room Temp 30°C.

Can i use this "http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/24228.pdf" Method 2 & 3.

Anyway thankz agian for the guide.

[Gizmo]

Pin 7 is connected directly to power, while pin 5 is attached to an RC network. Theoretically, attaching to pin 5 should provide cleaner power because of the filtering. However, this has no bearing on your weird temp readings. We could leave pin 4 of the Attansic chip completely disconnected and it wouldn't make any difference to your temp readings, because we are not reading that chip. There are two reasons that we make mods to that chip:

1) The Attansic chip is attached to the CPU thermal diode. If we simply solder wires from the Winbond chip to the thermal diode, the two chips will interfere with each others' ability to read the diode. So we disconnect the Attansic chip from the thermal diode on the CPU.

2) Unfortunately, if we disconnect the diode from the Attansic chip, pin 4 is left floating, and the Attansic chip will likely go into OTP mode and shut the computer down. So we have to do something to essentially disable the Attansic chip. That something is that we tie pin 4 to pin 5. This pulls pin 4 high, making the Attansic chip think the CPU is quite cold, and everything is hunky-dory.

Since you are getting intermittent readings of -1C, I'm inclined to suspect that you have an intermittent short between pin 4 of the Attansic chip and the solder pad that it was originally attached to.

You can certainly wire up the kits mentioned in methods 2 and 3, however, bear in mind that these kits typically work better when using a shielded wire to carry the signal from the thermal diode. In our case, we don't have that luxury, because the cathode of the thermal diode is tied directly to ground at the CPU socket. In addition, if you wire up one of these kits, you will have to disconnect the wiring that you have done to attach the diode to the WinBond chip. Or am I misunderstanding your question?

P.S. Be really careful of your CPU. I have killed a couple of chips now because of this mod, since it disables the Attansic OTP, and the software function in the WinBond chip never gets a chance to kick in because the CPU locks up just before it goes bye-bye. I'm investigating how to go about biasing the thermal diode so that I can properly read it from the Winbond chip without having to disable the OTP function.

[waifaq]

Originally Posted by gizmo

Pin 7 is connected directly to power, while pin 5 is attached to an RC network. Theoretically, attaching to pin 5 should provide cleaner power because of the filtering. However, this has no bearing on your weird temp readings. We could leave pin 4 of the Attansic chip completely disconnected and it wouldn't make any difference to your temp readings, because we are not reading that chip. There are two reasons that we make mods to that chip:

1) The Attansic chip is attached to the CPU thermal diode. If we simply solder wires from the Winbond chip to the thermal diode, the two chips will interfere with each others' ability to read the diode. So we disconnect the Attansic chip from the thermal diode on the CPU.

2) Unfortunately, if we disconnect the diode from the Attansic chip, pin 4 is left floating, and the Attansic chip will likely go into OTP mode and shut the computer down. So we have to do something to essentially disable the Attansic chip. That something is that we tie pin 4 to pin 5. This pulls pin 4 high, making the Attansic chip think the CPU is quite cold, and everything is hunky-dory.

Firstly thank for replying my questions.
I get the idea pin 5 vs. 7

So u mean connecting pin 4 to pin 5 or 7. Is to trick the Attansic OTP the CPU are still cool. Well i get the IDEA.

Since you are getting intermittent readings of -1C, I'm inclined to suspect that you have an intermittent short between pin 4 of the Attansic chip and the solder pad that it was originally attached to.

U suspect the solder wiring is touching the pin 4 & solder pad, supposedly we should lift up the pin 4 from the solder pad right ? I will double check it & maybe resolder back a new pair.

You can certainly wire up the kits mentioned in methods 2 and 3, however, bear in mind that these kits typically work better when using a shielded wire to carry the signal from the thermal diode. In our case, we don't have that luxury, because the cathode of the thermal diode is tied directly to ground at the CPU socket. In addition, if you wire up one of these kits, you will have to disconnect the wiring that you have done to attach the diode to the WinBond chip. Or am I misunderstanding your question?

I don't quite understand & little confuse here. I don't have problem getting STP cable here. "thermal diode is tied directly to ground at the CPU socket" can't we desolder the pin ?

P.S. Be really careful of your CPU. I have killed a couple of chips now because of this mod, since it disables the Attansic OTP, and the software function in the WinBond chip never gets a chance to kick in because the CPU locks up just before it goes bye-bye. I'm investigating how to go about biasing the thermal diode so that I can properly read it from the Winbond chip without having to disable the OTP function.

I really hope u can figure out way, to keep our Attansic OTP function at the same time we can use the thermal diode reading. Does methods 2 and 3 work with this, while keeping our Attansic OTP function. Instead we have direct reading thru winbond, we can read from SMBus.

Remember the -1°C

I suspect is my PC placing "horizontal or vertically" that accidentally log -1°C. From my last restart until, it been running for 2days. My MBM5 shows my PC running for 50hours, did not log -1°C reading. Anyway i will double check it agian.

One more things i need to ask. I got another NF7 running. But i doesn't seem to get the OTP function. In bios setting tweaking FSB & Voltage. Below there is setting CPU Over Temp "IIRC 60,70,80,90°C"... doesn't seems to work. Even i set the lowest. Is this a OTP function ?

But confirm the next BIOS section. Where monitor CPU & Voltage rail.
The Shutdown System & Alarm is working fine. But it take 5sec or more to shutdown the main power. Well is better than nothings.

Thankz

[Gizmo]

Originally Posted by waifaq

Firstly thank for replying my questions.
I get the idea pin 5 vs. 7

So u mean connecting pin 4 to pin 5 or 7. Is to trick the Attansic OTP the CPU are still cool. Well i get the IDEA.

Exactly.

Originally Posted by waifaq

U suspect the solder wiring is touching the pin 4 & solder pad, supposedly we should lift up the pin 4 from the solder pad right ? I will double check it & maybe resolder back a new pair.

That is what I suspect. It is also possible that you are just picking up spurious noise on the diode. That reading is EXTREMELY sensitive to external circuit noise. If noise is the problem, adding something on the order of 1000 pF or so between the WinBond chip's sensor input and ground should help that.

Originally Posted by waifaq

I don't quite understand & little confuse here. I don't have problem getting STP cable here. "thermal diode is tied directly to ground at the CPU socket" can't we desolder the pin ?

Yes, you can desolder the pin. However, this is a multilayer board, the socket pin is quite large relative to the through-hole in the board, and this is an embedded ground plane, which is quite efficient at removing heat when someone tries to solder or desolder on it. Getting the pin clean and free of any electrical contact with the ground circuit will be.........difficult.

That being said, even running STP and leaving the pin tied to ground would probably be sufficient for our needs, particularly if one applies a little capacitive filtering at the IC reading the measurements (such as what I mention above about putting 1000 pF across the WinBond chip).

Originally Posted by waifaq

I really hope u can figure out way, to keep our Attansic OTP function at the same time we can use the thermal diode reading. Does methods 2 and 3 work with this, while keeping our Attansic OTP function. Instead we have direct reading thru winbond, we can read from SMBus.

Theoretically, method 2 would work. Method 3 is only applicable where you need the absolute most accurate measurement possible, in which case you don't want ANYTHING else in the circuit.

Originally Posted by waifaq

One more things i need to ask. I got another NF7 running. But i doesn't seem to get the OTP function. In bios setting tweaking FSB & Voltage. Below there is setting CPU Over Temp "IIRC 60,70,80,90°C"... doesn't seems to work. Even i set the lowest. Is this a OTP function ?

But confirm the next BIOS section. Where monitor CPU & Voltage rail.
The Shutdown System & Alarm is working fine. But it take 5sec or more to shutdown the main power. Well is better than nothings.

Thankz

AFAIK, the CPU Over Temp function is based off the WinBond readings of the socket thermistor. There is no mechanism for setting the temperature at which the OTP function of the Attansic chip trips. In other words, it is all controlled by software, and so depends on the frequency with which the WinBond chip is scanned by the relevant software.

[waifaq]

Originally Posted by gizmo

Yes, you can desolder the pin. However, this is a multilayer board, the socket pin is quite large relative to the through-hole in the board, and this is an embedded ground plane, which is quite efficient at removing heat when someone tries to solder or desolder on it. Getting the pin clean and free of any electrical contact with the ground circuit will be.........difficult.

That being said, even running STP and leaving the pin tied to ground would probably be sufficient for our needs, particularly if one applies a little capacitive filtering at the IC reading the measurements (such as what I mention above about putting 1000 pF across the WinBond chip).

Theoretically, method 2 would work. Method 3 is only applicable where you need the absolute most accurate measurement possible, in which case you don't want ANYTHING else in the circuit.

Thank for explaining.

Originally Posted by gizmo

AFAIK, the CPU Over Temp function is based off the WinBond readings of the socket thermistor. There is no mechanism for setting the temperature at which the OTP function of the Attansic chip trips. In other words, it is all controlled by software, and so depends on the frequency with which the WinBond chip is scanned by the relevant software.

In the BIOS there is two temp controller
PC Health Status
>CPU Shutdown Temperature
I can get this works.

But
SoftMenu III Setup
>CPU Over Temp. Protect
I could not get this works.

I get what u mean for Attansic OTP. It actually function by itself from the hardware. And there is no mechanism to control it from the software.

If anything wrong, do correct me

Originally Posted by gizmo

That is what I suspect. It is also possible that you are just picking up spurious noise on the diode. That reading is EXTREMELY sensitive to external circuit noise. If noise is the problem, adding something on the order of 1000 pF or so between the WinBond chip's sensor input and ground should help that.

The "-1°C reading" doesn't seems to appear anymore maybe just for that day only.
For the safe side, i better get the 1000pF ready 1st, just incase i need it in the future.
Which type 1000pF should i get & does the Volt play important role ?
From google the result return, some are "Ceramic" type & volt range from 50-500V
I not sure which to get. Can u recommend or show to me ?
10Q

So i solder the 1000pF in between of this ?

Originally Posted by gizmo

4) If you follow the trace from the pad of pin 4, you will see that it goes to a resistor (a little black thing with the numbers 103 on it) and a capacitor (a little brown thing next to the resistor). Solder one end of the wire to the junction of the resistor and capacitor.

5) Solder the other end of the wire directly to pin 102 of the Winbond chip. WARNING! THIS PIN IS EXTREMELY DELICATE!

[Gizmo]

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