First post, by Maeslin
Here's an interesting conundrum.
I have on hand a little single board computer (Axiomtek SBC8242VE)for which the manual offers full documentation and jumper settings for pretty much any 486 out there (incl. AMD/Cyrix 5x86s) as well as for the Pentium Overdrive.
The CPU voltage is also fully adjustable to either 5V or 3.3V via jumpers.
The board is currently running an AMD 5x86-133 at a nice leisurely 160Mhz without the slightest issue, with 64MB of RAM total (2x32). Tried high-density 64MB SIMMs with no joy, but 64MB total is more than enough for the application and I'm uncertain low-density 64MB SIMMs would work either.
However, odd twist, the CPU socket is physically a 168-pin Socket 1.
I happen to have one of those Pentium Overdrive (P24T / POPD5V83) chips on hand.
Now I've managed to procure:
- full technical documentation for said Pentium Overdrive, which also includes helpful interconnection schematics and comparisons between standard 486 pinouts and the OD chip.
- 'spare' 168-pin socket to use in making the eventual adapter.
I'm still trying to find either a LIF or ZIF Socket 2 or 3 (238 or 237 pins) which would become the 'top' of the adapter (no way I'm soldering on the chip directly). If anyone has any insight on finding those antiques It would be much appreciated.
End result, with much ressource juggling and physical alteration to the IRQ lines of a few PC/104 cards, would be a stratum 1 timeserver/gps repeater with both a gps time reference and an eventual rubidium source and 8-10 serial ports, each with individual IRQs. The Pentium Overdrive experiment is mainly out of curiosity and because any linux kernel more recent than the very early 2.6.x ones have... issues with 486-class hardware (amongst other things, cpuid instruction = kernel panic for CPUs which lack it and said instruction is used OFTEN in the early kernel code. Making it boot is a huge bitch.)