This repository contains documentation on the SNES PPUs, 5c77 (S-PPU1) and 5c78 (S-PPU2). Right now there isn't much here, but I'll add more stuff here over time.
The die shots for both PPU is available at siliconpr0n, which I have been using for tracing to figure out how they work. Currently the tracing progress is:
5c77: Completed
5c78: Completed (Simulation)
Simulation setup and hosted by @quietust