PSoC5-z80 v4 – now runs ZX81 too…

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The principle used for the previous z80/CPM board support was using the WAIT signal, in response to an IORQ request from the Z80. This could not be applied to the ZX81.

I have kept the basis of previous software for memory access, the VGA output and the (non-perfect) PS2, but completely modified the Z80 interface. BUT thanks to that wonderful PSoC5 (I don’t get anything from Cypress for saying that), the hardware remains the same !!!

ZX81 needs a switchable NMI generator, some logic around NMI/HALT/WAIT, a way to force NOP on the Z80 when executing D-FILE with A15 high (while in M1), and acquisition of the D-FILE char (via FIFOin, and a DMA).

The keyboard was emulated by multiple control registers muxed together, and selected by A8-A15.

Result is :

z80 interface

I doubt it can be of any help, but the sources for PSoC creator are here.

Also needed would be the Eagle project :

All files here (v4 bug corrected – not manufactured).

And files to put on the uSD card, folder structure here :

Files in those folders were taken from :

Grant Searle, RC2014, S100, Z80-MBC2 and open81 in sz81.

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