Human interface on XMEGA-A3BU Xplained:
- Led green (close to USB connector) is on at power on
- Led 0 is on when USB line is in IDLE mode, and off in SUSPEND mode
- Led 1 blinks when USB host has checked and enabled PHDC interface
- Led 2 is on when PHDC has validated association
- SW0 and SW1 Push Button can be used to send a measure