using a Raspberry Pi RP2350 to emulate the gate array:
https://bread80.com/2024/08/11/pico-garry-2350-part-1-signals/
https://bread80.com/2024/08/25/pico-garry-2350-part-2-fsigs-fixed-signals/
For the full thread:
https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/creating-a-replacemant-gate-array/