I've got a SAMS70N19 board. SAM-BA running from ROM works just fine, but I've tried to make multiple Atmel Start USB device projects, and none of them work.
One thing that seems odd to me is that I've provisioned the board with a 16 MHz crystal - which is supposed to work (indeed, SAM-BA seems happy), but I don't see anything in the config where you tell the UPLL what the frequency is. Does it just "know" whether it's 12 or 16 MHz?
Has anyone gotten an Atmel Start USB device example to work on any x70 ?