I'm thinking about reading up on 10/100 Base-T or USB 2.0 and trying to make something. I saw there was a CDC project on TT-04 (https://github.com/TinyTapeout/tt04-usbcdc), but I didn't see a follow-up after the silicon shipped. I have been writing off anything exceeding ~100 MHz on an analog I/O path. I don't think we have characterization data for the I/O (S-params or anything), but would be happy to hear otherwise.