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Micro ATX 486 - what's the degree of interest?

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First post, by Nitroraptor53

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Original Post:

3/4/2020: Hi guys! I was wondering - how many people have a loose 486, 5x86, or Pentium Overdrive Chip and no spare motherboards? Well, apparently, quite a few! Even I have a DX4-100 (not Overdrive) that none of my 486 motherboards support! As you probably know, there's the NuXT, which I have spoken to the creator of. JD (creator of the NuXT) is willing to design a board IF I can get some results. But we're just one hobbyist, I need help.
The materials that we need that are no longer in production:
Video Chipset (VGA)
Motherboard Chipset (486,5x86,POD compatible)
So we have agreed an FPGA is required. To be more specific, two of them. One for each of the functions above. We also need a PGA237 CPU socket, with the lever, like this: http://www.cpushack.com/images/socket3.gif

For the motherboard chipset, it just needs to work with any Socket 1/2/3 CPU.
For the video chipset, I have more specific requirements:
-MDA
-Hercules
-CGA
-EGA
-VGA
-SVGA
-XGA
-Voodoo 2
and if you're feeling up to it:
-Plantronics Colorplus
-Tandy/PCjr
PM me if you'd like to know more!
Also, I've been informed. An FPGA may cost thousands of USD. As much as I'd love to have that kind of money to pay you, I unfortunately do not have it. I have estimated the cost of the motherboard to be $340-550 per board. : / If you're an FPGA designer and would like to work something out, contact me @ jurassicpgamer93@gmail.com, thanks for reading.
3/24/2020: Now considering the AMD Elan 520 with cache. But two problems:
1. Where the hell do I find them in bulk???
2. Would it be possible to add cache? (512k?)

Spoiler

10/12/2020: I think we have to do this with an AMD Elan SC520, if at all. I might be getting some money in the next couple weeks. Would anyone, if I get this money, design a board with the Elan SC520 as a CPU? PM me if so, and let's talk.

Last edited by Nitroraptor53 on 2020-10-13, 02:30. Edited 5 times in total.

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Reply 1 of 123, by jheronimus

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Honestly, simply a 486 motherboard with ATX connector and support for all CPUs would be awesome. I think a whole new VGA chipset with Glide compatibility would be an overkill. IMHO, people put Voodoos in 486 systems mostly for shits and giggles — there is no need for such a combination.

Reply 2 of 123, by matze79

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Why not build something around the ao486 Core ?
Just drop all legacy shit, and put whole Thing into a FPGA.

AO486 with Bus Interface would be really cool!
https://www.youtube.com/watch?v=v8WYNmkepCA

https://youtu.be/cdMd4kKhCh0

https://www.youtube.com/watch?v=TlRKV6cUvf4

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Reply 3 of 123, by Nitroraptor53

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jheronimus wrote on 2020-03-05, 11:03:

Honestly, simply a 486 motherboard with ATX connector and support for all CPUs would be awesome. I think a whole new VGA chipset with Glide compatibility would be an overkill. IMHO, people put Voodoos in 486 systems mostly for shits and giggles — there is no need for such a combination.

Agreed, though I've never seen a POD with Voodoo.

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Reply 4 of 123, by Nitroraptor53

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matze79 wrote on 2020-03-05, 11:07:
Why not build something around the ao486 Core ? Just drop all legacy shit, and put whole Thing into a FPGA. […]
Show full quote

Why not build something around the ao486 Core ?
Just drop all legacy shit, and put whole Thing into a FPGA.

AO486 with Bus Interface would be really cool!
https://www.youtube.com/watch?v=v8WYNmkepCA

https://youtu.be/cdMd4kKhCh0

https://www.youtube.com/watch?v=TlRKV6cUvf4

Well, check the comment section of LGR's NuXT video ; )

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Reply 5 of 123, by keenmaster486

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What would be mind blowing is if this could be fit on a board small enough to be used in a laptop. That’s been my dream for a while, to create a new retro laptop for tinkering and DOS gaming.

I flermmed the plootash just like you asked.
World's foremost 486 enjoyer.

Reply 6 of 123, by Deunan

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Interfacing a physical 486 to anything modern is a major PITA - the 486 has 5V I/O and nothing these days can handle it. A ton of fast level shifters would be required, this makes the mobo design another problem.

An older, 5V 486 would probably not work at 3V3, certainly not anywhere it's rated speed. The newer dual-voltage chips will but I do wonder if the I/O pins (which are still meant to work at 5V) will switch quickly enough at 3V3. I mean even the original 5V design had such serious signal integrity issues that VLB mobos could only have 3 slots, and even that is not reliable if all are populated.

I'm not saying it can't be done, just that the requirement of that mobo to have support for all 486-class CPUs will make it much more complicated and costly. Plus then there's the BIOS code, it's one thing to come up with a HW design and another to have all the low-level software required to handle all these chips.

As a side note, there is a 486 soft-core already available? Well, there goes another project idea. Not that I had time for it... Well, I might still make a 386 one, for the fun of it. Thanks for the YT links though, at least I know what to search for 😀

Reply 7 of 123, by derSammler

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Nitroraptor53 wrote on 2020-03-05, 04:43:

I was wondering - how many people have a loose 486, 5x86, or Pentium Overdrive Chip and no spare motherboards?

I don't see the problem. Just because you have a loose CPU, you don't need to build something from it. Also, socket 1/2/3 mainboards are not rare. If you need one, you can buy a used one.

Nitroraptor53 wrote on 2020-03-05, 04:43:

An FPGA may cost thousands of USD.

Who told you this? Not even an official Xilinx Evaluation Kit costs that much (e.g. Spartan-7 Evaluation Kit is less than $700) and a single FPGA chip alone is actually quite cheap, ranging from $10 to $100 depending on the number of gates, cells, and blocks.

Nitroraptor53 wrote on 2020-03-05, 04:43:

I have estimated the cost of the motherboard to be $550 per board.

That's just ridiculous, sorry. No one on this planet would spend $550 for a 486 mainboard. You can buy 10 old, used ones for that amount of money.

Reply 8 of 123, by Nitroraptor53

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derSammler wrote on 2020-03-05, 15:48:
I don't see the problem. Just because you have a loose CPU, you don't need to build something from it. Also, socket 1/2/3 mainbo […]
Show full quote
Nitroraptor53 wrote on 2020-03-05, 04:43:

I was wondering - how many people have a loose 486, 5x86, or Pentium Overdrive Chip and no spare motherboards?

I don't see the problem. Just because you have a loose CPU, you don't need to build something from it. Also, socket 1/2/3 mainboards are not rare. If you need one, you can buy a used one.

Nitroraptor53 wrote on 2020-03-05, 04:43:

An FPGA may cost thousands of USD.

Who told you this? Not even an official Xilinx Evaluation Kit costs that much (e.g. Spartan-7 Evaluation Kit is less than $700) and a single FPGA chip alone is actually quite cheap, ranging from $10 to $100 depending on the number of gates, cells, and blocks.

Nitroraptor53 wrote on 2020-03-05, 04:43:

I have estimated the cost of the motherboard to be $550 per board.

That's just ridiculous, sorry. No one on this planet would spend $550 for a 486 mainboard. You can buy 10 old, used ones for that amount of money.

Could be reduced, but no video, PCI, or USB. Also, you probably haven't looked at costs for mainboards. You could get 10 broken mainboards for that money. : |

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Reply 9 of 123, by Nitroraptor53

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derSammler wrote on 2020-03-05, 15:48:
I don't see the problem. Just because you have a loose CPU, you don't need to build something from it. Also, socket 1/2/3 mainbo […]
Show full quote
Nitroraptor53 wrote on 2020-03-05, 04:43:

I was wondering - how many people have a loose 486, 5x86, or Pentium Overdrive Chip and no spare motherboards?

I don't see the problem. Just because you have a loose CPU, you don't need to build something from it. Also, socket 1/2/3 mainboards are not rare. If you need one, you can buy a used one.

Nitroraptor53 wrote on 2020-03-05, 04:43:

An FPGA may cost thousands of USD.

Who told you this? Not even an official Xilinx Evaluation Kit costs that much (e.g. Spartan-7 Evaluation Kit is less than $700) and a single FPGA chip alone is actually quite cheap, ranging from $10 to $100 depending on the number of gates, cells, and blocks.

Nitroraptor53 wrote on 2020-03-05, 04:43:

I have estimated the cost of the motherboard to be $550 per board.

That's just ridiculous, sorry. No one on this planet would spend $550 for a 486 mainboard. You can buy 10 old, used ones for that amount of money.

Could be reduced, but no video, PCI, or USB. Also, you probably haven't looked at costs for mainboards. You could get 10 broken mainboards for that money. : |

"Oh I'm a good old rebel, now, that's just what I am."
MIcro ATX 486 Project
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Reply 10 of 123, by wiretap

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Nitroraptor53 wrote on 2020-03-05, 16:26:

Could be reduced, but no video, PCI, or USB. Also, you probably haven't looked at costs for mainboards. You could get 10 broken mainboards for that money. : |

Uh, no. Fully working 486 motherboards. We aren't talking about eBay ripoff prices here. Even on eBay, I haven't paid over $60 for a high end VLB 486 board that is fully functional. Most of mine I have paid around $30 for.

That said, if a new iteration was made with a modem process, around $200 is the max I would pay.. and that's pushing it.

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Reply 11 of 123, by cyclone3d

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$60 for a 486 board? The only one I paid close to that was for a 486 PCI/ISA SBC.

All my regular 486 boards I have paid almost nothing for.. and I probably have about 15-20. Really need to thin out the herd.

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Reply 12 of 123, by Nitroraptor53

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matze79 wrote on 2020-03-05, 11:07:
Why not build something around the ao486 Core ? Just drop all legacy shit, and put whole Thing into a FPGA. […]
Show full quote

Why not build something around the ao486 Core ?
Just drop all legacy shit, and put whole Thing into a FPGA.

AO486 with Bus Interface would be really cool!
https://www.youtube.com/watch?v=v8WYNmkepCA

https://youtu.be/cdMd4kKhCh0

https://www.youtube.com/watch?v=TlRKV6cUvf4

After doing some research, I think it would be best to have an ao486 on a uATX board with 4x EISA slots would be best. Is this possible? I can't do it on my own though, I have no idea how to design a board.

"Oh I'm a good old rebel, now, that's just what I am."
MIcro ATX 486 Project
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Reply 13 of 123, by Deunan

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derSammler wrote on 2020-03-05, 15:48:
Nitroraptor53 wrote on 2020-03-05, 04:43:

An FPGA may cost thousands of USD.

Who told you this? Not even an official Xilinx Evaluation Kit costs that much (e.g. Spartan-7 Evaluation Kit is less than $700) and a single FPGA chip alone is actually quite cheap, ranging from $10 to $100 depending on the number of gates, cells, and blocks.

I might be nitpicking here because you are right that for a project like this the FPGA shouldn't cost more than a 200$ - but, strictly speaking, an FPGA can easily cost thousands. Even a hundred thousands USD. And that's the ones you can buy off-the-shelf. There are some you can't even get a price for, unless you are important enough to Xilinx or Altera (now Intel) to bother talking to you. And then there's probably another category of prices, that's for cutting edge military applications but since not much is known about it, I can only speculate.

Reply 14 of 123, by Nitroraptor53

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Deunan wrote on 2020-03-05, 17:20:
derSammler wrote on 2020-03-05, 15:48:
Nitroraptor53 wrote on 2020-03-05, 04:43:

An FPGA may cost thousands of USD.

Who told you this? Not even an official Xilinx Evaluation Kit costs that much (e.g. Spartan-7 Evaluation Kit is less than $700) and a single FPGA chip alone is actually quite cheap, ranging from $10 to $100 depending on the number of gates, cells, and blocks.

I might be nitpicking here because you are right that for a project like this the FPGA shouldn't cost more than a 200$ - but, strictly speaking, an FPGA can easily cost thousands. Even a hundred thousands USD. And that's the ones you can buy off-the-shelf. There are some you can't even get a price for, unless you are important enough to Xilinx or Altera (now Intel) to bother talking to you. And then there's probably another category of prices, that's for cutting edge military applications but since not much is known about it, I can only speculate.

I meant to prototype, pay designer, etc. JD told me this.

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Reply 15 of 123, by Nitroraptor53

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Is ao486 slower or faster than a DX4 75?

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Reply 16 of 123, by keenmaster486

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I say a single FPGA chip with 486, VGA, SB16, and IO controllers would be ideal. A ton of work though.

I flermmed the plootash just like you asked.
World's foremost 486 enjoyer.

Reply 17 of 123, by cyclone3d

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Why EISA? EISA cards are generally quite expensive, especially if you want any really good ones.

ISA or EISA and PCI would be a much better option, especially for card availability.

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Reply 18 of 123, by wiretap

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The last standalone FPGA system I designed at work was around $150k. This was with a full SQA audit and software license though, for a proprietary piece of nuclear non-safety related equipment. (i.e COTS type replacement) Specialized nuclear safety related or military grade builds would easily be 5-10x the amount.

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Reply 19 of 123, by Nitroraptor53

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cyclone3d wrote on 2020-03-05, 17:24:

Why EISA? EISA cards are generally quite expensive, especially if you want any really good ones.

ISA or EISA and PCI would be a much better option, especially for card availability.

Knew someone would ask! EISA is backwards compatible with ISA, and I don't want to neglect EISA cards, which I love. A single PCI slot would also be available.

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