Introduction
I know that this topic isn’t exactly brand new, but so far I had no reason to fight with it myself. When Intel released the first new Pentium III processors with on-die 2nd level cache, code name ‘Coppermine’, most of the processors came as Slot1-versions and only the 500 and 550 MHz models were released for the ‘new’ FC-PGA 370 Socket.
This Socket doesn’t really come across as that new, because it’s physically identical to the Socket370 used by all Celeron-processors available today. Technically there is a serious difference though, which is why it is impossible to run the new Socket-Coppermine in old Socket370-motherboards that were designed for Celerons.
FC-PGA Coppermines Now Up to 750 MHz
Recently Intel made a major step towards this FC-PGA-Socket and released clock speeds up to 750 MHz in this package, so that even the most performance hungry people might consider going for this version rather than the Slot1-Coppermine.
I didn’t really want to have that much to do with this FC-PGA (‘flip chip pin grid array’) in the recent months and used happily the good old Slot1-Coppermines in SECC2-package.
How to Run a Fast Coppermine in FC-PGA Without a FC-PGA Motherboard?
This changed rapidly when I recently received a powerful high-speed (800 MHz, unlocked!) Coppermine processor in the sweet little FC-PGA format. Suddenly I realized that I had no decent platform to run it in. So far you could only get FC-PGA motherboards with the ‘value’ chipset i810e, the one with the built-in 3D-deccelerator. This is changing right now, but I needed to run this new processor instantly and I did not want to believe that I couldn’t. The first thing that came to my mind was the bunch of Socket370/Slot1-adapter cards that were still lying in my CPU-drawer and so I thought I’d give them a shot. I took one of my Asus ‘S370’ adapter cards, plugged the Coppermine in it and tried my luck in a Asus P3C-L i820-motherboard, anticipating nothing but defeat, because I was aware of the changes that were made to Coppermine’s pin-out. It came as it had to, the system remained absolutely silent.
Intel’s Data Sheets and Frank Voelkel’s Article
OK, I thought. So we’ve got to do something about it. I won’t give up that fast! Therefore I went to one of my favorite locations on the web, Intel’s developer website. It took only a few seconds and I could take a good look at the datasheet of the FC-PGA Coppermine processor. At the same time I remembered an article at the German ZDNET that I had heard about recently. Frank Voelkel, currently still editor for PC Professionell, the German PC Magazine, had given a description of how to run FC-PGA Coppermine processors in old Socket370 Celeron-motherboards. The article, called ‘Der Sockeltrick‘ = ‘The Socket Trick’, had stirred up quite a bit of commotion in the hardcore overclocker scene recently and people had done their best to translate Frank’s words into English. Luckily my German is pretty good, so I read the article and compared the stuff with the datasheet. Five minutes later my soldering iron was heating up and I was getting ready for some minor surgery (better minor surgery than no surgery!) on the Slot1-adapter card and some microsurgery on my FC-PGA Coppermine as well.
Before people are annoying me with ridiculous emails I would like to point out that I do NOT claim that I was the first to find out about the issue I am describing here. I am aware of Frank’s article and Frank’s aware of mine. I am not aware of any people that tried to translate and copy this article into English or other languages, but I am sure that there are many of them. I will obviously only give credits to the initiator of this issue, and that is Frank Voelkel, who by the way will join Tom’s Hardware Guide on April 1, 2000. Thanks Frank, we can’t wait to welcome you in our team!
Getting an Socket370/Slot1 adapter card ready for FC-PGA Coppermine – The Theory
Although Socket370 and FC-PGA370 are physically identical, Intel decided to make sure that Coppermines would not work in any Celeron-platform. Frank says in his article that Coppermine has 40 different pin assignments compared to Celeron, which sounds pretty hopeless. I haven’t counted them personally, but I believe that it’s a lot. In this case however, we only have to concentrate on 3 or possibly 5 pins and the work required to make the ‘slocket-card’ work with Coppermine is very very simple.
- The Voltage Issue
Celeron usually runs with 2 V core-voltage and many older Celeron-motherboards can’t supply the much lower 1.65 V that are required by Coppermine. This is not a real issue for the ‘Slocket’-cards though, because you can plug those in any Slot1, at least into any single-CPU motherboard. To keep your Coppermine alive you should obviously chose a motherboard that can supply 1.65 V and plug the slocket-card in there. To make sure that your slocket-card doesn’t do strange things to the VID-signals, it is helpful if you can adjust the voltage (1.65 V) already on the adapter card. This way the Slot1-motherboard will definitely get the correct voltage-request. The Asus S370 gives you that option; you only need to find out the right jumper settings.
Getting an Socket370/Slot1 adapter card ready for FC-PGA Coppermine – The Theory, Continued
- The ‘RESET’-pin
Intel was quite humorous when designing the pin layout of Coppermine. To ensure that Coppermine was incompatible to Celeron the ‘Reset#’-pin was placed at a new location (AH4) . The old location (X4) known from Celeron is called ‘Reset2#’, but it has no official function anymore. No processor in the whole world would ever start to work without a signal to ‘Reset#’ in the moment when you turn on your system. Placing ‘Reset#’ at a formerly ‘reserved’ pin of Celeron made sure that Coppermine would never work in Socket370.
- SlewCTRL and RTTCTRL
Frank picked those two GTL+-protocoll pins and suggested to pull them down. By default both pins are where Celeron used to have ‘reserved’-pins, so that in Socket370 those pins are not connected and therefore ‘high’. I have not enough documentation to give my own comment to it, but I know that my Slocket-card works just fine at up to 933 MHz with both of those pins left at ‘high’. It might be safer to use pull downs though.
- Pin AM2
This pin, found in one of the corners of the Socket, is another way that Intel chose to make sure that Coppermine doesn’t run in Celeron-sockets. ‘AM2’ is one of the 50 ‘ground’ supplying pins of Celeron. Coppermine doesn’t use this pin, but it doesn’t like 0V or ‘ground’ on it. As soon as AM2 of Coppermine is connected to ground, the processor doesn’t run. The datasheet does actually not mention a word about this behaviour.
Theoretical Summary
I compiled this above table out of Intel’s datasheets.
Here is the scheme of Coppermine’s pin-out:
I marked the 5 pins of interest in red.
Theoretical Summary, Continued
What we need to do now is
- Make sure that the ‘Reset#’-signal of Socket370, that arrives at the useless ‘Reset2#’-pin (X4) of Coppermine gets ‘redirected’ to Coppermine’s ‘Reset#’-pin (AH4). The simplest way to do this is connecting the two pins with a simple wire.
- Pull down ‘RTTCTRL’ (S35) and ‘SLEWCTRL’ (E27) with two 330 Ohm resistors. This procedure might not be necessary, but it is the safer way. I did not do it and my Coppermine 800 runs perfectly.
- Disconnect ‘AM2’. This is easier said than done, but there is a pretty archaic way to do it.
That’s what needs doing in the left upper corner.
Theoretical Summary, Continued
And here is a close look at the two pins that might require a pull down. I marked all the pins that carry ‘ground’ (VSS) black. These are places where you could get the ground for the pull-down resistors.
Getting an Socket370/Slot1 adapter card ready for FC-PGA Coppermine – The Practice
The operations I did on my Asus S370-card were very simple. First I set the jumpers to 1.65 V.
Then I took an old floppy ribbon cable and removed a short part of one of the wires. This wire is perfect for such operations. Then I simply soldered a connection between AH4 and X4:
This is all that needs doing on the card if you don’t fancy the pull-down operation as I did. PLEASE DON’T FORGET TO TAKE THE PROCESSOR OUT OF THE SOCKET WHILE SOLDERING OR MANIPULATING !!!
Getting an Socket370/Slot1 adapter card ready for FC-PGA Coppermine – The Practice, Continued
Now the card looked like that:
The next step can be rather touchy. We need to make sure that there’s no connection between pin ‘AM2’ and the Socket. This is so because there’s hardly a way to make sure that the pin AM2 of the socket does not have a connection to ground. The only way would be to actually drill the socket-pin out of the PCB. I doubt that this is a feasible solution. The alternative is to isolate pin ‘AM2’ of the actual processor. You may have a good idea how to do this, I didn’t. I finally forced myself into something rather archaic. I actually removed the pin of my CPU. Intel’s data sheet claims that it doesn’t have any purpose and the processor still runs perfectly.
Here’s the proof. I removed pin AM2. It’s actually very easy, just try to bend it and it comes off. DON’T REMOVE THE WRONG PIN!! The other two pins that you may find missing in this picture as well are the ‘BSEL’-pins. You don’t need to touch those!
Getting an Socket370/Slot1 adapter card ready for FC-PGA Coppermine – The Practice, Continued
This is all I had to do to run my Coppermine in any i820 or Apollo Pro 133 motherboard. But if you want to do it perfectly, you might want to attach the pull-down resistors to ‘RTTCTRL’ and ‘SLEWCTRL’.
This picture shows where the pins are at and I also suggested a nice ground-point where you can fix both 330 Ohm resistors. Please make sure that the wires of the resistors are insulated! 1/8 or 1/4 W resistors will be just fine.
Final Words
This is another hobbyist-article for people who know how to use a fine-tip soldering iron and who now what they are doing. As usual I have to point out that neither I, Thomas Pabst, not Tom’s Hardware Guide will take any responsibility if you might occur any damages to any part of your computer system, the processor or the slocket-card due to this article. The suggested procedure is only for people who own an Asus S370 Socket370/Slot1-adapter or something similar, who also own a Slot1-motherboard that is able to supply 1.65 V, who don’t want to wait until FC-PGA370/Slot1-adapter cards will become available in the mass market (which should be rather soon), and who actually have a good reason why they want to plug a FC-PGA Coppermine into a Slot1-motherboard.
Thanks, enjoy!
A special thank you to Hans-Juergen, Christian and Intel Germany! Without you I would never have had a reason to even think of this issue.
