The only processor update I know of, is that for a while Tundra semiconductor made 10MHz versions of the 80C85. I happen to have 2 of them. A processor + adapter card could be plugged into the CPU socket that enables a high speed mode, but that mode would have to be shut down when accessing the legacy components.
On Tue, Jun 2, 2015 at 12:33 PM, Ken Pettit <[email protected]> wrote: > I've actually looked at this before thinking it would be cool to have an > expansion bus plug-in device that is basically a new processor on the > system bus. Can't be done. The problem is that all the signals connecting > to the system bus are buffered, meaning they are one-way traffic only. The > address bus can only be driven by the 80C85 CPU and the data bus direction > control is the same. > > Ken > > On Tue, Jun 2, 2015 at 9:27 AM, Hiraghm <[email protected]> wrote: > >> Okay, so the system bus is used to connect to the DVI drive/video >> expansion, but what are its total capabilities? >> In an earlier message I wished for a cpu/ram upgrade for the M100. On >> reading about the extRAM in Portable 100 issue November 1990 (page 17), I >> began to wonder if one of you hardware types could build a very small >> cpu/ram upgrade board that "takes over" for the CPU over the system bus. >> >> Maybe this is how QUAD adds the banks of RAM, I don't know. That's why >> I'm asking, because I don't know. >> >> Not only would such a hardware upgrade speed up and expand the capability >> of the M100 (would probably require a customized ROM via REX), but it would >> make CP/M or even a custom FreeDOS (except FreeDOS is 32 bit :( ) possible. >> > >
