I have several pico-SAM9G45s and an Atmel AT91SAM9G45-EKES (evaluation/development card). Most everything I've done and tried works fine on BOTH platforms. But..
I've implemented the USB UDPHS (device) and UHPHS (host/EHCI). On the EKES, I can connect the host port to the device port and everything seems fine. But it doesn't work on the pico-SAM9G45. And I can connect the pico-SAM9G45's device port to the EKES's host port and (again) everything seems fine. But connecting the pico-SAM9G45's host port to the EKES's device port doesn't work.
So the bottom line is that there's something wrong or missing with my implementation of the EHCI on the pico-SAM9G45. The difference, hardware-wise, between the pico-SAM9G45 and the EKES is that the pico-SAM9G45 uses an "SMSC USB2514 USB 2.0 High-Spped 4-Port Hub Controller" external to the AT91SAM9G45. Does anyone have any suggestions on what to look at or as to what I'm missing?