Lots of good work and news going on with this project, I figured it was about time to actually update this page with what’s going on.
The soldered prototype for the PSX -> C64 adapter is now done, as can be seen here:

The converter now does the following:

1. Determines whether a normal controller is plugged in or a guitar controller, and maps buttons accordingly
2. Turns on analog mode for guitar controller and successfully reads whammy bar. (Updates later about getting this working for all those interested)
3. Maps Strum up, Strum down, and guitar lift up to static values on one of the POT lines, which allows the C64 to receive ALL information from the guitar (except start and select button)
4. Allows button macros to be programmed onto the R1/R2/L1/L2 buttons in controller mode, up to 127 button sequences PER macro
5. If the user selects analog mode on a normal controller, it will map the left analog stick to the normal digital directions
6. And converts all buttons successfully of course.

After a hefty debugging session, the physical adapter is solid and works great with both a guitar controller and normal dual shock controller. It was amazing to try all my old games with a PS2 controller (as well as some Amiga games and Atari 2600, haven’t tried the Sega Master System yet).

Also, I’ve started writing the actual Shredz64 (guitar hero) game for the C64. I started out with a simple debugging routine to show the status of what guitar buttons were being pressed. Here are two screenshots (literally) of the C64 reporting whats happening on both the fret board and strum bar/lift sensor:

Here you can see me pressing random buttons on the fretboard

And here I’m struming up a down a few times, then I lift the guitar up

While this program was written in BASIC, the final Shredz64 program is being written in a combination of C and 6502 assembly using the CC65 cross compiler, which I got up and running a few days ago. I’m currently developing in an emulator environment and am waiting for parts to arrive to build a cable to transfer the program to the C64 itself for testing.

Anyway, so much more to come, but things are progressing nicely! I’ve found out that this project is featured in Engadget which is great, I hope to be making updates more regularly now that I know people are reading. If you have any questions, feel free to email me: twestbrook AT synthdreams DOT com. Huzzah!