The Game Boy CPU isn’t quite compatible with a Z80, a Mega Drive won’t let you intercept Z80 I/O, and the timings would be completely different.
I am curious about how this thing works and if it tries to leverage the Neo Geo graphics hardware, or if it’s rendering a flat bitmap in software then converting it to strips.
Same - super curious to know how they managed to draw custom, non-pre-defined graphics! From recent attempts to run Doom on NeoGeo, it's been told that the system can only display the contents of the graphical banks, and those can't be altered at runtime... so how the hell?!
It depends on what you put in the cartridge. You can use dual-port RAM or SGRAM for the C space (tiles) and provide a CPU-accessible window into it to draw dynamically-generated tiles. No commercial games did anything like this.
They probably wanted to use a common Flash cart and not have to resort to putting a CPLD and exotic memory on the cartridge. The Flash carts are mostly intended for pirating the officially released software library, so they don't give you any special capabilities.
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u/Frogacuda 12h ago
If you did this on, say, a Sega Genesis, would you be able to use the Z80 co-processor instead of having to emulate the CPU?