I recently got a Leonardo, and wanted to explore the fun of USB.
But the current Arduino USB stack is very limitted, had difficulties to implement other classes than CDC Serial / Mouse / Keyboard.
plus, it's integrated into the sketch, so no matter you want it or not, it occupies some portion of your precious ROM and RAM.......... (~4kb!!!!!)
Thus, I removed the internal USB stack and brought LUFA to Arduino:
- no longer takes up ROM and RAM when USB not needed
- unleash the full power of the hardware USB (Device/Host/OTG)!!!
- ohh... plus you got 2 more on-board LEDs.......... TXLED0/TXLED1 and RXLED0/RXLED1
the library is in a very early development state, I'll probably put out more examples when I successfully implement more USB class for my own application.
ideas, issue reports, patches, pull requests are always welcome 