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Greetings, As part of a project to get an old Transam Tuscan S100 Z80 system up and running I have recreated its machine code monitor from the source code listing found in the back of the manual, This runs in a z80 emulator but I want to try it on an actual Z80 cpu. To achieve this I need a compatible enviorenment, Emil's Z80 MECB with RomWBW has been used for the general testing of a new board ive prototyped, but now I need to find a way to run the code image. The 2KB code in eprom sits at address 0xF800 but the Tuscan system has some magic to re-map the eprom to address 0 for its first instruction. I need to find a way of emulating this somehow on the MECB system.

Here is a picture of my new board, ive just managed to get it all tested: Over the weekend I dumped a set of four 2k basic roms, I think they have errors but its all I have.
These machines are a bit rare to say the least. However one owner has setup a groupsio channel and we are lucky one of the early users has made contact. Hopefully this will lead to more information becoming available.

Best regards, David.

djrm wrote: Sun Aug 09, 2026 10:07 pm ... but now I need to find a way to run the code image. The 2KB code in eprom sits at address 0xF800 but the Tuscan system has some magic to re-map the eprom to address 0 for its first instruction. I need to find a way of emulating this somehow on the MECB system.

Nice work! Your tidy point-to-point wiring is a nice example of grid prototype card use.

The temporary re-mapping of ROM during boot-up sounds very similar to what we needed for the MC68008 CPU Card.

This was implemented by using a counter, to temporarily alter the PLD’s address mapping of ROM / RAM (for the 0000 based memory segment).

In the case of the 68008, this was just remapped for the 8 cycles (following reset release), required to load the Reset vectors (from 0000), then ROM / RAM resumed it’s operational memory map.

It's taken a while but now have the new Tuscan board operational, albeit only under control from romwbw at present. The limitation is because I haven't yet managed to get the address trampoline working in the z80 pld, due mainly by lack of knowledge in pld design.

I have an external keyboard, dot matrix printer, 6402 UART, and dip selection switches working. This allows me to run the MITSI machine code monitor on the MECB board. I had to recompile it to a ram location for now. The idea is to be able to run unmodified ROM software eventually when I get the z80 pld modified.

Thanks for the heads-up on the 68k pld. I need to check this out.
Best regards, David.