A project log for Discrete YASEP

a 16-bits YASEP computer (mostly) made of DIP/SOIC chips like in the 70s and 80s... with 2010's twists!

Yann Guidon / YGDES 10/25/2015 at 01:106 Comments

Note from the author : please discregard the updates, as my inventory becomes more precise and I add "notes for myself". Thank you :-)

Rumaging in my "archives" I found old riches, pulled from boards of the mid-90s era, that landed in the recycle bin. Then I reached more recent landscape of tapes and reels and trays... Which of these could be used to build the prototype then the real device ?

In the "old pulls, misc samples and eBay finds" department we have :

(tbc, stay tuned)

PS: Sorry for the rants, I was only looking for 74HC138 chips :-P I found the SOIC tape, I needed 4 PDIP for the keyboard and I found 6, victory :-D

I now proceed to wiring the keyboard's control logic.

update : found other pulls!

Time to get a programmer !


Xark wrote 10/25/2015 at 22:44 point

Hello, perhaps you already found this, but Googling around for your "classic" Lattice MACH210 CPLD parts, I came across this link which appears to be software for programming them: (which the page claims is now "freeware").

Whether it makes sense to use them or not in this discrete project, is another interesting question. :-)

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Yann Guidon / YGDES wrote 10/25/2015 at 22:51 point

Thanks ! I'll have a look :-) I have AMD parts btw.

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Yann Guidon / YGDES wrote 10/25/2015 at 22:55 point

Alright... I thought I should dump old PCs but it seems I must keep at least one in working state and find a "suitable OS"... I am not sure that MS-DOS6.22 will be enough though.

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esot.eric wrote 10/25/2015 at 03:44 point

It's fun digging through stuff like that. I managed to scrap a couple SGI machines a while back, and their PCBs are a friggin' wealth of high-speed MSIs RAMs and stuff. (nevermind some really high speed ECL stuff, which is a bit beyond my expertise)

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Yann Guidon / YGDES wrote 10/25/2015 at 03:55 point

we both love to indulge in geek porn. And black screens, btw.

I have a couple of ECL boards from a "mythical" machine, BTW. It must be seend and held in your hands to really understand the meaning of "computation" back in the days. It was really physical...
I hope that my projects can bring back some of the excitment. It's not magic, it's hard engineering and work :-)

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esot.eric wrote 10/25/2015 at 04:14 point

haha, this description is awesome... a mythical machine! Yeah, that SGI consists of *several* boards which each weigh more than most laptops. It's quite tangible. But also quite cool because so much can be learnt from looking at the chips used, and how they were wired-up. Quite a few (but not all) are easy to find datasheets for, even some of the high-end stuff (at the time) like the RAMDACs.

Fun times, thanks for that!

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