I got my first 5MHz NSC800 adapter board back today. I have one built and installed in an M100 dedicated to CP/M. It worked as planned.
The only mods to the M100 were- 1. Remove 80c85 and install socket 2. Install Z80 version of M100 OS in 100nsec eprom 3. And of course RECXPM for ram. I have a design done for an 80c85 board as well, but I'm not sure if I will get them built. I probably will, if only to complete the project. It certainly is fast! Feels pretty nice indeed. I'm just going to use it and observe. It should be fine. One thing... the faster speed does soak up more current. I see a jump from about 60mA to about 85 mA. Also, my BCR port hack for serial video now runs at 115200 Baud....2x faster. I suppose that the regular serial port can now run reliably at 76800 baud. May test that. Cassette port will be non functional for several reasons! The 2x speed definitely kills that...as does the lack of SID and SOD on the NSC800. Sound in general is 2x higher pitch. Modem rates themselves are unchanged. Anyhow, all in all, a reasonable set of tradeoffs for a 2x speed up.
