uPD7220 Graphics V5 experimental update Apr 2024 (SV Pantazi)

DO NOT BUILD (yet), project is largely untested!

This is an updated design based on the original project (updgfx_r0) By Dylan Brophy (NTI) published on Hackaday (https://hackaday.io/project/164728-upd7220-retro-graphics-card-and-vga-hack).

The update has a RC2014 bus type interface, 1M (2x512kB) of SRAM, a GAL22v10 to decode IO and provides for PLCC (Z7220) and DIP40 footprints. It has yet to be fully tested but it appears to work.

Many thanks to Dylan for his work on the original project!.

SVP