USB in FPGA

• https://github.com/pbing/USB: FPGA USB 1.1 Low-Speed Implementation
• https://github.com/ulixxe/usb_cdc: Single/Multi-channel Full Speed USB interface for FPGA and ASIC designs
• https://github.com/greatscottgadgets/luna: Amaranth HDL framework for monitoring, hacking, and developing USB devices