I've designed a small board with an S70N19 wired up for USB. It has a 16 MHz crystal connected to it and I was very careful to go through the schematic checklist.
The prototype doesn't enumerate on the USB bus. The datasheet seems to imply that I should expect it to do so, as it should start SAM-BA, which should notice that there's a 16 MHz crystal and I should see it try to show up as a USB device... right?