The hardware for the 65C02 CPU board seems rock solid, so my efforts have shifted back to software, primarily getting the CTMON65 monitor working better, adding new commands, and integrating with the SD Card System. It does pretty much everything a basic monitor should do, and can also load Intel HEX format files from the SD card and even auto-execute them. I ported my Tiny BASIC interpreter to it and added commands to save/load programs to the SD card. 40 year ago when I got my KIM-1 my dream was to have a BASIC interpreter and a disk system, and now I’ve built the whole thing from the ground up.
At VCF MW in a couple weeks this will be on display. Still not sure whether it’s worth making these CPU boards for sale since there was never a generic DOS for 6502 based systems, so only people who want to write their own code would be interested.
The breakpoint feature works but other than an initial test, it hasn’t been fine-tuned. CTMON65 installs a default NMI/IRQ handler which points to a section of code that displays the registers and falls back into the monitor. You can poke around RAM and then continue running the code under test. Once this is stabilized a bit more it will get pushed to the github site, along with the matching Tiny BASIC.