The Papilio Arcade Kit is a DIY kit thatprovides everything needed to recreateclassic Arcade games such as Pac-Man.Open Source HDL projects provide thehardware definition for study,implementation, and extending.The Papilio Arcade Wing provides, 12bitVGA, Delta-Sigma Audio, and DB9 Joystickports.
ZPUino is an implementation of the 32-bit Open Source ZPU processor. It is a small implementation that is meant to be used with the Arduino IDE. It is capable of speeds up to 100Mhz and can run on the Papilio Platform.
Those can be problematic due to need of pullup/pulldowns, and 60MHz USB bus will definitely not like it.
I understand there exist some DDR USB chips, that only use 4 data pins. Their availavility is low, however.
Honestly, I'd prefer to share some signals with the WING_B pins for example. Eventually in such a way that official wings would still work.
We can add a RC if needed, just to raise it slowly during startup if needed.
My SDRAM controller does not at use CKE at all, but the pin may have been ground when the board powers up. I guess we can do some testing first.
Regarding SDRAM CKE: I'll point out that the data sheet's "recommended power-up sequence for SDRAM" includes bringing CKE low and then high again. Although it doesn't say how long it needs to be low -- Hamster's SDRAM controller only does it for a single clock cycle, no longer, so it probably doesn't make any difference.
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