[edanuff]

Very cool arcticle! I've played around with this sort of thing and at one time had the idea to create a small FPGA board that could be used as a pin-compatible drop-in for either the NES PPU or the TMS9918 but shelved it. The new miniSpartan board is going to be a great board for experimenting with this sort of thing:

https://www.kickstarter.com/projects/1812459948/minispartan6...

[TheZenPsycho]

would you have done just a straight clone or would you improve the visual output in some way? what sorts of things could you do while retaining pinout compatibility?

[edanuff]

HDMI output would have been the main display improvement but given where a PPU or a VDP sits in these architectures, you could do a lot of fun stuff including running your own CPU core on the FPGA. (Edited - thought there was a wait pin from the PPU to the CPU but looks like it's an interrupt)