Added a Keyboard to my 6502 using a PIC MCU

A project log for HBC-56: 65C02 + TMS9918A on a backplane

HBC-56 A homebrew 8-bit computer with a backplane. Initially with a 65C02 CPU card, a TMS9918A VDP and dual AY-3-8910 audio.

Troy SchrapelTroy Schrapel 11/29/2021 at 12:320 Comments

My build has had input in the form of a NES controller for a while now, but that's a bit limiting. Time for a keyboard. 

After watching Ben Eater's PS/2 videos, I decided to add support for PS/2, but to expand on my skillset, I decided to implement the PS/2 controller using a PIC microcontroller. Something I've never user before.

I ordered a bunch of PIC16F627A's from AliExpress and got to work. There was a bit of a learning curve for PIC assembly, but once I got my head around the instruction set, it was fairly straight-forward. 

My keyboard controller contains a 16 byte circular buffer and outputs the head of the queue in parallel using an interrupt pin.

I cover the process in some detail in the above video.

More improvements are planned to the keyboard controller and the rest of the build.

Stay tuned :)