Since the 3 Chip Computer got some surprising fame the past days, I thought I should show the final version before euthanizing it. Both the breadboard and the components onboard are required for other projects. It's time to pull the plug on it, literally speaking.
The keyboard support is in place, although a little wonky, but functional. Typing with one hand is always challenging, but here's the obligatory "hello world":
I never bothered to implement the BASIC interpreter, though. It's currently just echoing what I'm writing. The kernel is still just 80 bytes and could easily respond to a couple of commands with the remaining reserved kernel space.
A few people have asked what's the purpose with the 6502 when the ATmega16 is there. In short, the AVR is busy rendering video and can't do much else. Notice that even the keystrokes interrupts this timing-critical process thus disturbing the video signal. There's basically not much oomph left to draw from it. The 6502, on the other hand, is playing carelessly in the background with its own stuff.
I'm glad so many enjoyed this little project, and I appreciate all feedback, good and bad.