WCH Arduino core: https://github.com/openwch/arduino_core_ch32
Commit: d76716239cdf8a084a5045c3dfd3151b3f69eeec
TinyUSB: https://github.com/hathach/tinyusb
Commit: 3c6524eb95c0055d3acb18ac37220ff0a48ee326
Original copyright/license headers retained. WCH peripheral SDK is restricted to WCH microcontrollers. Arduino-derived core files retain LGPL notices. FireFLY-specific glue is MIT licensed.
