A few months ago I made up some PCBs for a Z80 computer using designs from allthingsmicro.com Unfortunately their website has been down and there seems to be no way of contacting them.

I have had the boards laying around for a few months and finally decided I want to try and build the thing. Only problem is that I don't have the ROM file.

My question is that if I go and download any ROM file for a Z80 computer off the internet, will it work with the board? Will any firmware work with any Z80 computer.

From my understanding the board is pretty standard, using the Z80 CPU, SIO and CTC and 256k of RAM.

Thanks for any help!

  • \$\begingroup\$ The WayBack Machine is your friend :) \$\endgroup\$ Jan 3, 2016 at 11:27
  • \$\begingroup\$ Tom that's awesome! How was I not aware something like that existed... Just a shame you have to sign in to download the files :( but thanks anyway, that will come in handy in the future! \$\endgroup\$
    – Ben
    Jan 3, 2016 at 11:36
  • \$\begingroup\$ Never mind, was worth a try :). web.archive.org can be a great tool for finding long lost pages and files. \$\endgroup\$ Jan 3, 2016 at 11:37
  • \$\begingroup\$ is this a S100 bus system or something else? \$\endgroup\$ Jan 3, 2016 at 23:34

1 Answer 1


No. You cannot use just any Z80 ROM with an arbitrary hardware design. There are aspects to the hardware design that will be very specific and the proper ROM for that hardware would uniquely address these factors. Some of the issues:

  1. Size of memory space decode for the ROM.
  2. Address base for the ROM space decode.
  3. Speed of the ROM in terms of access time versus Z80 clock frequency.
  4. Size of any RAM memory space.
  5. Decoded address range for the RAM.
  6. Whether the HW design requires the built in refresh for DRAM.
  7. Supported range of I/O peripherals.
  8. Specifically supported I/O base address for each peripheral.
  9. Method by which user interacts with the Z80 system whether that be via UART, keyboard/video or some other means.

When you take even this small set of factors into account it becomes obvious that there is no such thing as a "standard configuration".


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