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 <mailto: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
<mailto: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 <mailto: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.
