No, it is a plug in board.... but it plugs into the CPU socket (ah....which does not exist!) On my bench system I did the work to take out the CPU and added a socket. Then I plug an expansion card into it.
Good idea though about the system bus, I'll have to think about that. I'm almost done a full patch to the M100 Main ROM which makes it 8080/Z80 compatible. In this case I should be able to switch to running Z80 in M100 mode too! Steve On Sat, May 30, 2020 at 2:57 PM Ken Pettit <petti...@gmail.com> wrote: > Hey Steve, > > Oh great! One more emulation I need to add to VirtualT! ;) > > Nice work! How do you wire it it? System bus? > Ken > > On 5/30/20 5:04 AM, Stephen Adolph wrote: > > ...and I just now this second got the NSC800 to run in the M100 > successfully. > It is driving the LCD at the moment. > I think the interrupts are different, and more work to do, but it is > officially alive. > yay! > > > On Sat, May 30, 2020 at 6:32 AM William stewart <wstewart2...@yahoo.com> > wrote: > >> Stephen, >> Are you suggesting a swap of the 8085? >> >> Sent from my iPhone >> >> On May 29, 2020, at 7:46 AM, Stephen Adolph <twospru...@gmail.com> wrote: >> >> Reviving this thread. >> Now that we have a solid CP/M application written in 8080, there should >> be a way to boot into CP/M using the NSC800. >> I dropped this project some time back but it is time to revive it, as a >> processor swap would be a cleaner way to expanding the CP/M application >> universe for the M100. >> >> >> >> On Thu, Jul 11, 2019 at 10:30 AM Stephen Adolph <twospru...@gmail.com> >> wrote: >> >>> Motivated by 2 things >>> 1) discovery of the NSC800 Z80 processor that is 80C85 like >>> 2) continuing to work in the direcition of CP/M >>> 3) and recalling that there are 5MHz 80C85 parts out there.. >>> >>> I started to work on a dual CPU card for M100 that enables a couple of >>> things; >>> - standard 2.5MHz 80C85 operation (default) >>> - switchable clock for 80C85, supporting 5MHz >>> - switchable CPU enabling NSC800 at 2.5 MHz. >>> >>> Board is done and heading to the fab. VHDL is mostly done. >>> >>> I don't expect this board will be wildly popular but maybe it has some >>> interest Double speed M100 seems interesting on it's own, let alone being >>> able to support Z80 CP/M applications. >>> >>> >>> Any interest? >>> >>> I have purchased material to make 5 of these. >>> >>> A few more comments. >>> - to install this board you need to remove the 80C85. that's some >>> effort to do >>> - to run at 5MHz you need to upgrade the 81C55 to a 5MHz version. >>> That's also some effort. >>> - NSC800 runs about 5$ on ebay. >>> - fast 80C85 can be had for under 5$. >>> - fast 81C55 can be had for under 5$. >>> - to run at 5MHz you might also find you need a faster main ROM, and >>> faster RAM. TBD on that; will advise after I do some testing. >>> >>> >>> >>> >
