So, in the last post we reported that we had the keyboard mostly working. In the meantime, we managed to figure out the remaining problems with the communications protocol, and map the remaining keys.
As a result every key now works as it should, the clicky lock keys illuminate their LEDs, and behave as expected. All of the dedicated lines for special keys, like the left and up cursor keys that live outside of the keyboard matrix on the C65 are also correctly handled.
Suddenly it started feeling a lot more like a computer, now that we could type on it and interact with it. We could do long-press on RESTORE to get to the freeze menu (reset is now only via the dedicated reset button the left side of the computer).
It really feels very nice. The work we put into having sub-millisecond latency on the keyboard has really been worth it. There is absolutely no perceptable delay, and it just works as it should. The indicator LEDs for the LOCK keys work perfectly, and with their clickiness and different tactile resistance, you know with certainty when you press one. In short, we are really happy with the result, and hope that everyone who uses a MEGA65 will enjoy it as much as we do.
So, now onto getting the cartridge port working...