Interested...

adalbert wrote on 2020-12-15, 01:53:

Does anyone know where did these adaptors came from?

China.

adalbert wrote on 2020-12-15, 01:53:

Were they commonly used in some kind of hardware, or could it be a custom design done by this guy?

Custom design, but not by the person who sold them. These were fairly common at that time, assuming that you looked hard enough in China's used market.

They're no longer in production as far as I know, so if you need one of these contraptions, you have to buy it from a collector.

All right, so now I started messing around with a PCB design for mobile Tualatin (with socket 479 - physically incompatible with coppermine CPUs) to S370.

I prepared component symbols for mobile Tualatin and desktop Tualatin, most pins are identical but there are some differences:

Pins present only in Mobile Tualatin: EDGECTRLP# GHI# DPSLP# (desktop has SLP#) TESTHI (not needed?) TESTLO (not needed?) […]
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Pins present only in Mobile Tualatin:
EDGECTRLP#
GHI#
DPSLP# (desktop has SLP#)
TESTHI (not needed?)
TESTLO (not needed?)

Pins present only in Desktop Tualatin:
THERMTRIP# (not needed?)
SLP# (mobile has DPSLP#)
SLEWCTRL
RESET2# (mobile has only one reset)
DYN_OE
DETECT
CPUPRES# (probably pulldown would be enough)
BR1# (mobile has only BR0#)

I'm trying to make a 4-layer PCB (6-layer would be easier to route, but $$$), it needs quite a bit of optimisations, for now I just have been using an autorouter. I will have to redo the connections and fix trace lengths, but first I need to make sure what to do with listed pinout differences.

Soldering will be quite challenging, I want to use a PGA 479 socket for the mobile part, and for the desktop part desolder pins (with hot air) from broken s370 CPU, inner pins would be surface soldered, and the rest would be inserted from top (through hole)... PCB would be only 0.8mm thick, so maybe they would still reach the socket.

Mobile Tualatins are larger than Coppermine, so this is pretty difficult to do.

May I ask why? Mobile Tualatins were still 0.13 process, this adapter would make sense if you make PCB interposer that converts it to Coppermine pinout, allowing to use them on pretty much any CuMine compatible board.

Paadam wrote on 2021-06-04, 13:02:

this adapter would make sense if you make PCB interposer that converts it to Coppermine pinout

It will be possible to solder it in such a way that it will work in Coppermine boards (i will add appropriate jumpers)

Paadam wrote on 2021-06-04, 13:02:

May I ask why?

Just wondering about OC possibilities of lower voltage mobile parts 😜

Paadam wrote on 2021-06-04, 13:02:

Mobile Tualatins were still 0.13 process

True, but could they be 'binned' better than desktop parts?

That's really cool, and a lot of work! Nicely done 😀

Given how rare / valuable the 1.4ghz tualatin has become recently, making it possible to use laptop tualatin parts (of which there are many) with a desktop board does open up some opportunities and more available parts.
I do think Paadam has a point though, I wonder what it would take to make a version that builds-in modifications similar to that korean socket 370 adapter?

I've actually got a Pentium III 850 one of these CPUs that I snagged off of eBay a while back because I thought it looked interesting. Still haven't tried it through so I don't even know if it works.

These were almost for sure used in some embedded application where they wanted lower power usage.

Mine apparently came from Kontron Canada Inc. and was from 2005 as seen in the picture below:

Great, thanks for that photo, it's helpful! I have never seen the bottom side. It's a coppermine variant obviously, but now I can see that it probably also uses vias directly under BGA pads. So I should be able to see where these resistors on bottom and top connect. Though it looks like data traces are on the internal layers (mine were on the external) - maybe it has even more layers, like 6 or so.

Thermalwrong wrote on 2021-06-04, 13:29:

wonder what it would take to make a version that builds-in modifications similar to that korean socket 370 adapter?

It should be very easy, it should be possible to configure the same PCB to be used in both Tualatin and Coppermine systems.

Paadam wrote on 2021-06-04, 13:02:

May I ask why?

Because mobile Pentium III CPUs are multiplier-unlocked (downwards), which means the ISA or PC/PCI -equipped S370 configs would blow any mobile K6 or C3 out of the water for good? 😀

@adalbert, if there is a strong possibility that changing the multipliers on desktop S370 mobos will work, I'm actually willing to support the development of your project with my hard-earned $$. Please PM me if I can in any way increase the chances of making it happen.

@Revolter thanks, if I will see some chances of actually manufacturing it i wil PM, but for now i start to see a lot of design issues to resolve 😁

I updated the schematics with DIP switch for Vcore and a switch to select Tualatin / Coppermine motherboard support, I also connected bunch of other pins and it should have more chances of working...

Multiplier-wise i also should add a button/header to switch between high and low multiplier, but unfortunately I don't think you can go as low as you want. I think there mostly are only two multiplier settings, like 6x and 10x.

I created 3d model for the socket and pins, I see that there will be a lot of issues with soldering that... Will need to think about other way of attaching S370 pins, through-hole probably won't work. BGA - too difficult to align them. The photo of adapter that was posted earlier had a second piece of PCB stacked, so maybe i should do something like that...

True, but could they be 'binned' better than desktop parts?

Hardly. Mobile chips usually had very conservative ratings.

Hi, this looks amazing, great work! Did you ever get it working?

I would love to take a look if you're able to share the Kicad project?

Thanks

adalbert wrote on 2021-06-05, 16:20:

@Revolter thanks, if I will see some chances of actually manufacturing it i wil PM, but for now i start to see a lot of design i […]
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@Revolter thanks, if I will see some chances of actually manufacturing it i wil PM, but for now i start to see a lot of design issues to resolve 😁

I updated the schematics with DIP switch for Vcore and a switch to select Tualatin / Coppermine motherboard support, I also connected bunch of other pins and it should have more chances of working...

Multiplier-wise i also should add a button/header to switch between high and low multiplier, but unfortunately I don't think you can go as low as you want. I think there mostly are only two multiplier settings, like 6x and 10x.

I created 3d model for the socket and pins, I see that there will be a lot of issues with soldering that... Will need to think about other way of attaching S370 pins, through-hole probably won't work. BGA - too difficult to align them. The photo of adapter that was posted earlier had a second piece of PCB stacked, so maybe i should do something like that...

For what it is worth. I have a Mobile Pentium III fixed on a socket 370 adapter. I actually already had it marked as "not-working/defective", because on several i440BX Slot 1 motherboards it would not post. That was with a slotket adapter of course, of which I have quite a few.
Then later I gave it another shot on an VIA Apollo Pro 133A based native Socket 370 motherboard. A Chaintech 6AJA4. There the mobile CPU actually did run fine.