On Sun, Oct 1, 2023 at 8:38 AM Wouter de Waal via cctalk <cctalk@classiccmp.org> wrote: > > Hi all > > I re-discovered some eurocards I found in a box at a swapmeet long ago. > > It looks like a complete 8085 system. Lots of RAM, 2K EPROM, I/O, FDC. > > The strange thing is that the EPROM is mapped at F800, the code in there > looks like 8085 code, and looks like it wants to live at F800. And there's > RAM at 0000.
It might have run CP/M (which will run on an 8080, and therefore on an 8085). That needs RAM at location 0000 [1]. If the EPROM is mapped to F800 only (some machines mapped it to 0000 as well after a reset, this image was disabled after the processor jumped to F800 or wherever) then there might be a bit of logic to force a jump instruction onto the data bus after a reset to get the processor to run the code in the EPROM. [1] For the pedants, there were 'relocated versions of CP/M that could run on machines like an unmodified TRS-80 model 1 with ROM at location 0. These versions needed special relocated versions of all the application software and were generally pretty useless. -tony
