After doing a bit of testing, it turns out the only thing wrong with the Radio Shack TRS-80 Color Computer 2 that I got was the keyboard itself. I was able to get some schematics and I tested the PIA with a logic probe and manually jumpered the keyboard connector and I was able to type. This was both good and bad. It meant I didn't have to hunt down a long extinct PIA, but it meant I was going to have to repair a membrane keyboard. I took apart the keyboard to see how it was constructed...

Feeling like I don't have enough TRS-80 computers in my collection, I purchased a Color Computer 2 from eBay. There were only a few photos of it and not enough info to determine which specific version of CoCo2 it was. The seller only took the time to plug it in and say "no light, as-is untested." I got it for a good price because of that, and I'm sure because it was really dirty. Once I got it the first thing I did was hook it up and was delighted to find it works! Or at...

I've made some more progress on my software that allows the Raspberry Pi to act as a Commodore 64 disk drive. I was amazed at how much more of the IEC protocol was missing from the documents I have. One of the things that I found a little strange about the IEC protocol was there was no way to specify how much of the data you want. Once you say go, the sender is just going to send it all. It turns out that when ATN is asserted it doesn't mean abort , it just means pause. Took quite a...

If you've been following along here or on Twitter or Google+ you've no doubt seen the experimenting I've been doing with interfacing a Raspberry Pi in various ways with several retro computers like the Atari 800 and Commodore 64. My first project was using the Raspberry Pi to act as a converter for a USB gamepad to turn it into an Atari 2600 style joystick. After discovering Eric Nelson  on Twitter and seeing all the games he was playing on the Commodore 64, I really wanted to...

Got the kernel module for the Raspberry Pi that does the Commodore 64 IEC protocol working quite well. Managed to get rid of pretty much all the timing issues, and cobbled together a simple user space program to handle the file I/O. I can now read & write PRG files, even very large ones. It was interesting sending a file (by accident) larger than the C64's RAM, the poor C64 freaked out and overran even the screen and crashed. It was very cool to load a Demo without having to mess...