Electronics > Projects, Designs, and Technical Stuff
Cloning a Commodore PET-2001
GK:
I'm been meaning to upgrade from CPLDs to FPGAs in my home workshop for a while now and almost clicked the "buy now" button a couple of times, but just haven't gotten around to it so far; one of those ebay Cyclone dev boards or the like might be a good start.
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Anyone with an suitable reader can pull a 27XX from a vintage computer board and save the contents, but for the Tandy character set ROM you'd have to solder up an adaptor to fit a 27XX footprint and just ground any unused address and data pins. The ROM was a Motorola MCM6670, which was called a "Character generator", but that was just marketing as the part was nothing more sophisticated than a parallel in/out ROM with 5-bit words. The part was packaged in an 18 pin DIP which I don't think was originally socketed in the TRS-80.
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I was a bit slack this week end electronic project wise, but late this afternoon a couple of hours before having to attend to my weekly chook and duck poop shoveling chore, I at least made a rudimentary start on the case. I originally planned a 2U case but ended up deciding on 3U. I've finished the PCB layout for the keyboard interface and will etch that soon. The keyboard interface will get mounted on the opposite side panel to the video generator board and a torodial power transformer will get mounted onto the rear panel.
The 3U front panel will give me a healthy amount of room to layout all of the I/O connectors and control switches. Rather than rolling my own front panel labeled with Dymo tape, I've decided to splurge out and get the front panel done by Front panel express and have just downloaded the latest version of their "Front panel designer" software. I should get that out before the end of the working week, but the production and delivery delay will probably stall the completion of this project by another couple of weeks.
While waiting I think I might brush up on my BASIC and write a PET version of Atari Pong :D
Bicurico:
WOW!
Reading this thread looks like I am looking over the shoulder of the original PET creators.
I won't try to replicate it, as reason tells me I don't have space, knowledge, time, money and I could use an emulator.
Still, what a joy to look at your project.
:-+
BrianHG:
:-+ Excellent Job!
james_s:
--- Quote from: GK on June 17, 2018, 01:16:09 pm ---I'm been meaning to upgrade from CPLDs to FPGAs in my home workshop for a while now and almost clicked the "buy now" button a couple of times, but just haven't gotten around to it so far; one of those ebay Cyclone dev boards or the like might be a good start.
--- End quote ---
Well if you do, I've got a pile of random turnkey projects targeted to those boards which you're welcome to play with. Some are my creations, others are stuff I ported from elsewhere. It's an old part but still quite capable. You need a programmer too, the USB Blaster clones that are only a few dollars from China work just fine.
GK:
--- Quote from: Bicurico on June 17, 2018, 01:46:14 pm --- .............and I could use an emulator.
--- End quote ---
Some of us are a little masochistic ;D
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