Github, KERNAL mode and Cynthcart CC
The repository with all source code which I wrote so far, Eagle schematics (you can view it with the freeware version of Eagle) and the board layout is public now:
https://github.com/FrankBuss/kerberos
There are still two wires missing in the schematic, which I had to solder on my prototype, so I have modify the board again, but it is only a minor change, should be easy. The KERNAL replacement feature (without any additional line from inside the C64, just the cartridge in the expansion port) is already working, see this video:
https://www.youtube.com/watch?v=MH8j6iGqI5w
Notice the first line on the C64 screen :-) I'm using the same trick as EasyFlash, switching to Ultimax mode dynamically when the KERNAL space is accessed, and then switching back to normal mode. Now I can implement the load/save emulation to use the internal flash and finish the rest of the software.
Another good news about Cynthcart: Paul, the developer of the Cynthcart program, told me that he plans to implement MIDI CC messages as well, so it might be possible to use a pitch-wheel or a rotary encoder to adjust the pulse width of a square wave oscillator and other parameters, for interesting live performances and easier SID configuration.
