Need suggestion for USB SPI adapter that can work as full duplex SPI slave

[wb0gaz]

For the FT4222, there are drivers (PC-side), library and demo application, so there's a starting point there (the demo application seems very simple, and perhaps can be adapted, or at least provide some proof of concept.)

That's the environment I'm starting with, because it's got more of the needed elements defined than anything else that's been mentioned so far.

Tks,

Dave