The code linked there is all open, and has a USB device softcore. It's the most approachable FPGA USB implementation I've played with. edit: Here is the actual

The code linked there is all open, and has a USB device softcore. It's the most approachable FPGA USB implementation I've played with. edit: Here is the actual USB core that's in there: https://github.com/im-tomu/valentyusb/ https://github.com/im-tomu/valentyusb/