zebcrs wrote on 2022-11-26, 19:15:

It all started when doing some inventory in my components racks..... I found a tray of STP Elite chips with 40 cpu's in it and a […]
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It all started when doing some inventory in my components racks.....
I found a tray of STP Elite chips with 40 cpu's in it and an idea was born.
So now after some weeks of spare time doing schematics and some pcb layout the project starts to look like there is something.
Theese are the specs:
STPC Elite running at 100 Mhz.
168 pinn DIMM SDRAM PC100/PC133 3.3 volt ram socket.
S3 Trio64V+ chip with 2 mBytes of EDO memory.
Crystal CS4237B audio chip with a Raspberry Zero with external DAC running MT-32 emulation
SuperIO FDC37B782 and onboard Gotek
Onboard P.O.S.T display on port 80h
Powered by USB-C 5 volts.
Ports, POwer USBC, 15 pin joystick,VGA 15HD,Audio 3,5mm stereo,USB(Gotek).ps2 mouse and keyboard
In the front there are displays for MT32 and for Gotek running Flashfloppy with all the neccesary buttons.
The total build cost will be just around 100 Euros when buying used VGA and Soundcards for parts.
Everything will ofcourse be open source.
The schematics will be released in CADINT format as that is the program I use since I have a full license.
All schematics will be in PDF too and all gerbers are free as well.
Source codes are open too. At the moment I use Tiny Bios but it has problems with PS/2 ports. I am waitng for BIOS files from ST as I had an error in my old archive on the BIOS directory.

Whoa, that's an ambitious project! 😀
I have a few questions, if you don't mind me asking;
1. Have you done BGA PCB design before? With all the special multi-layer stuff that usually entails? How many layers are you using for the mainboard?
2. From what I can tell from looking at the layout picture, you're bringing out the PCI bus to a PCI connector? ...and also integrating a PCI-based Trio64 on-board? Which you'll scavenge from a real PCI card? Why? Oh wait, that connector on the left is the ram socket? Nevermind then!
3. Why is there a TVGA9000 mentioned in the schematics pdf?
4. Why would you scavenge sound cards for parts when the CS4237B chip is readily available on its own?
5. I have no idea what an STPC Elite SOC costs or where you can buy it (assuming you don't have a tray of them lying around 😉), but the 100 euro estimate seems a little ambitious?
6. Would you consider switching over to KiCad, which is more or less the de facto tool for hobbyists at this point? (and also free)

Excited to see where this project is going, I'll be watching! 😀

Edit: ...and, btw, cool to see more Norwegians in here! 😜

Yes, I have done a couple of BGA designs before. I am doing 6 layers here on this board to make it easier on the power planes. Last timne I did the STPC soc I did it in 4 layers but with all the extras on this time I chose 6 and the price to do 6 layers is way much better now than 20 years ago !!
The TVGA chip is the chip I started the design with but I changed my mind and went for the Trio instead 😀

When I scavenge a card I get the chip,eeprom, oscillator, and the gameport connector.
The STPC Elite SOC is really expensive !!! But I have 40 pcs from a tray I had in my storage. So ther cost i basically a bare pcb, ram socket , vga card and soundcard. The mt-32 emulation comes on top of the cost but I will mount the header.

Have been to busy to work so much lately but have updated the schematics a bit while I work on the PCB layout.
Have finished reversing the S3 card I bought and corrected quite a few thing in the VGA schematics. The VGA rom was way different then the datasheet part. Apart from that most of the signals where correct.
Have also moved around a few compontents on the ISA bus to better the layout a bit.

Hi,

Here are 2 boards I designed in 1998/2000 😀

zebcrs wrote on 2022-12-04, 17:02:

Have been to busy to work so much lately but have updated the schematics a bit while I work on the PCB layout.
Have finished reversing the S3 card I bought and corrected quite a few thing in the VGA schematics. The VGA rom was way different then the datasheet part. Apart from that most of the signals where correct.
Have also moved around a few compontents on the ISA bus to better the layout a bit.

Hi,
Did you progress ?