Some progress to report! I have gotten my test m100 to run with this card installed. It currently runs in 80c85 mode, but what is neat is that the big cpld is sitting between the cpu and the rest of the board. This is step 1. Prove that i can insert the cpld into the mix, because I need it to be the switching element between the NSC800 and the 80C85.
I'm also running the 80C85 at 3.3V, which is within spec and may save a bit of current. Next step is to get the nsc800 working. On Friday, March 1, 2024, Stephen Adolph <[email protected]> wrote: > I have so many Model T around here-- too many! One of the reasons is for > testing, but another reason is because I have different computers for > different use cases. > > For example, I have an M100 set up for CP/M using an NSC800 CPU using > REXCPM, and of course I have a normal M100 with 80C85 CPU again with REXCPM. > > So, I've decided my next widget is going to be a dual CPU card for M100, > so I can have Z80-based CP/M and normal M100 in the same box! > > Here is my proto board. It uses a great big CPLD to interface and manage > the switching between the two processors. It also will support dual clock > rates because... why not. > > I'll post updates as this progresses... Steve > > [image: image.png] > >
