Slightly OT: Handwired computer 8-O

[AtariNerd]

http://www.stevechamberlin.com/cpu/category/bmow1/

 

Sort of. Lots of wired discrete ICs,so only thosands and not millions of wires, but still.

 

Horrible flashback for some of you, a thing of beauty for some.

 

SPECS summary: The BMOW runs at 2MHz and has 512K RAM and 16K ROM. It is constructed with primarily 7400 series logic and over 1048 wirewrap connections

Edited May 29, 2009 by AtariNerd

[GroovyBee]

"Power draw is 10 Watts, 2.0A at 5V.".Almost as good as a pentium . P90 that is!

[deathtrappomegranate]

It's not a 6502 computer at all - it seems to be built from discrete TTL logic chips, in the same way that the first "microcomputers" were.

 

Cool.

[GroovyBee]

Seems to have A, X and Y registers which matches the 6502. I've not looked very closely at the design of it.

[AtariNerd]

It's not a 6502 computer at all - it seems to be built from discrete TTL logic chips, in the same way that the first "microcomputers" were.

 

Cool.

 

 

Thanks for the correction, I've modified the topic heading so as not to mislead.

[FastRobPlus]

Wow! And he says those posts are solid 10k gold. That CPU is not only gorgeous, but it's worth more than any modern one.

Edited May 30, 2009 by FastRobPlus

[mos6507]

That guy just earned the equivalent of climbing mt everest for geek cred.

 

Reminds me of this guy.

[AtariNerd]

From one of the comments on the Wired magazine article linked to from his webpage:

 

"The trouble with this technology, while it was generally bulletproof, was that the chips themselves suffered from a disease called “purple-plague” which was a crystalization of the junctions of the chips inside the plastic cases. The gold micro wires from the 1 mm square TTL “chip” which were soldered to the DIP pins inside the plastic case would corrode due to the dissimilar electrovalence of the 2 materials (pins were usually tin or nickle-silver plated steel) and the junctions would oxidize (purple, hence the name) and get brittle then break due to thermal expansion and contraction after about 5 years of use. Time was the factor, not the thermal issues. 7400 series TTL parts became quite scarce after 1985 and most “new” parts would last only about a year because they were manufactured about 5 years earlier. This effectively ended the “hobbyist” ability to build any computer or digital electronic equipment from scratch using boolean logic and wire wrap technology."

 

Though reading further, someone else seems to think that this uses mainly 20v8 and 22v10 PALs for logic, made much later.

Edited May 30, 2009 by AtariNerd

[+poobah]

I think the commenter on the purple-plaque is a bit, ahem, misguided.

Techniques to avoid the purple-plague problem were developed in the 60's (yes, the 60's!)

I don't ever recall a shortage of 7400 TTL, and I am quite certain that there is no failure spike at 5 years.

(By way of reference, most of our beloved A8s have a fair amount of 74xx TTL in them)

Edited May 30, 2009 by poobah

[kskunk]

Horrible flashback for some of you, a thing of beauty for some.

 

I think it's a thing of beauty, but he did cheat a little. There are a ton of programmable logic chips in there, which did exist back in the early 80s, but are quite a lot more powerful/expensive than 74-series chips.

 

If you want to see a really hardcore home made CPU, check out this guy:

http://www.homebrewcpu.com/Pictures/bu_3.JPG

 

No programmable logic there, just 74-series chips. He has about 10 times the chips and many more boards and wires.

 

BTW, I'm at the Maker Faire today so I'll get to see the mess o' wires in person.

 

- KS

[re-atari]

I think it's a thing of beauty, but he did cheat a little. There are a ton of programmable logic chips in there, which did exist back in the early 80s, but are quite a lot more powerful/expensive than 74-series chips.

 

If you want to see another 6502 built from discrete logic and eproms, check out http://web.whosting.ch/dieter/m02/m02.htm. Already a few years old, but still very impressive. Schematics, PCB layout and sourcecode can be downloaded there as well.

 

re-atari