vUSB - parasquid/mcu-iot-sensors GitHub Wiki
https://www.insidegadgets.com/2011/05/08/playing-around-with-v-usb-for-avr/
http://vusb.wikidot.com/hardware
https://codeandlife.com/2012/01/22/avr-attiny-usb-tutorial-part-1/
https://www.beyondlogic.org/usbnutshell/usb2.shtml
https://www.circuitlab.com/editor/#?id=zzy443
http://tuxgraphics.org/electronics/200810/avr-usb-slideshow-presenter.shtml
https://rayshobby.net/wordpress/hid-class-usb-serial-communication-for-avrs-using-v-usb/
https://www.instructables.com/id/ATtiny-V-USB-Project-Board/