Backplane and mainboard for a 6502 computer

posted Jan 4th 2012 11:01am by Mike Szczys
filed under: pcs hacks

[Quinn Dunki] has been busy through the holidays giving her 6502 processor-based computer a place to live. The most recent part of the project (which she calls Veronica) involved designing and etching a mainboard for the device. In the picture above it’s the vertical board which is right at home in the backplane [Quinn] also designed.

The project is really gaining momentum now. You may remember that it started off as a rather motley arrangement of what we’d guess is every breadboard she owns. From there some nifty hex switches gave [Quinn] a way to program the data bus on the device. Many would have stopped with these successes, but the continuation of the project makes the hardware robust enough to be around for a while. The single-sided boards are playing nicely together, and the next step is to redesign the ROM emulator to use chips for storage. [Quinn] alludes to a side project in which she plans to build her own EEPROM programmer to help with getting code into the experimental computer.

Comments [11]

tagged: 6502, backplane, mainboard, quinn dunki, veronica

11 Responses to Backplane and mainboard for a 6502 computer

YT2095 says:

January 4, 2012 at 11:26 am

Awesome! looks like ZED is going to have a little Sister :)
Your PCB work looks way cooler than my wire-wrap, if I had that same level of PCB skill and equipment as you have, I would be very happy! :)
I`m intrigued to see how you go about the O.S, I`m still working on mine and it`s a non trivial task.

I take my hat off to you, Well Done! :D

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Peter says:

January 4, 2012 at 11:56 am

Nice!

For authenticity, though, she needs to use 1702 UVEPROMS with their +5, +12 and +24(?) voltage requirements :-)

(I used to have some around here somewhere….)

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Techrat says:

January 4, 2012 at 11:58 am

That’s funny, I was just on her blog on my own to find out if any progress had been made, then I click back into hackaday after lunch, and now it’s the top story. Great minds think alike… Anyhow, I’m excited by this project, it makes me want to start designing/building a computer myself — unless Quinn wants to start making kits! My biggest question: Is this just being done in offhours? Do you not have a really demanding job? I just find that finding the *time* to do something like this is the hardest part of any project!

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ScottInNH says:

January 4, 2012 at 12:20 pm

Would be neat if these projects grow in the direction of becoming compatible with one or more of the old 6502 platforms like Atari 130XE or C64.

I take that back some.. this is plenty cool “as is”, but if there were more people doing this, and they each “competed” (like Atari vs. Commodore) AND they blogged about their developments/discoveries… THAT would be like, totally awesome! :-D

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Dude says:

January 5, 2012 at 12:11 am

your best bet would probally be apple, all the others used a lot of custom chips in their design, and unless you just got them you would be SOL. WOZ on the other hand used shift registers and unicorn farts to construct his design, all still available today

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- Quinn Dunki says:
  
  January 5, 2012 at 10:32 am
  
  Indeed. In the C64, the SID chip is notoriously difficult to replicate. My understanding is that is has some analog elements on the die, which is what makes it difficult to replicate or simulate. Each one was a teeny bit different to, so you’re aiming for some unknown “average” specification.
  
  I love unicorn farts. They smell like rainbows and taste like puppies.
- ScottInNH says:
  
  January 5, 2012 at 10:42 am
  
  Oh. I hadn’t meant to imply “no custom chips” at all. I was thinking more along the lines of basically a DIY Apple or C64 or Atari 8bit.
  (I’m aware of online plans to build the Apple 1)
- Quinn Dunki says:
  
  January 5, 2012 at 10:51 am
  
  Yah, a fellow named Briel is kicking ass in that regard. He’s built an Apple I replica (which you can buy), and an Altair 8800. He also builds frankenstein extensions to retro machines, like a 4MB RAM card for the Apple iigs (which Apple said couldn’t be done).
  
  http://www.brielcomputers.com/replica1.html
  (I have no connection to him, I just think his stuff is way cool)

Quinn Dunki says:

January 4, 2012 at 10:35 pm

Thanks for the warm fuzzies, everyone! YT2095, the software is actually something I’m really looking forward to. Low-level systems programming was the focus of my education, as it happens, though I haven’t done much of it in years. I was fascinated by disk head travel optimization algorithms. :)

Techrat, in my day job, I have a consulting and development company for iOS and Mac software. It’s time consuming, so I have to optimize my time carefully on these side projects.

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Andrew says:

January 5, 2012 at 1:05 am

Awesome! I’m a sucker for vintage computing, 8-bit CPUs, etc., and I’ve been watching this project on HAD for a while. Love the backplane. It looks like an old S-50 or some other micro bus type setup.

I’m an 1802 guy at heart but I’ve got a few 6502 chips in my parts bin so maybe I’ll have to try something like this too… but with numitrons or nixies for display.

It Shouldn’t be difficult to set up to run the same software that Kim-1 and Sym-1 systems were running back in the day except that we have so many better options for coming up with keyboard and display options.

Keep up the great work!

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Mattster says:

January 7, 2012 at 3:10 pm

@Andrew I thought I was the only one who still enjoyed the 1802. If it was good enough for space probes , it was good enough for me . I love being able to bring the clock down to 100khz for low power applications

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