I am using a SAM3U4e. I would like to use High-Speed USB, but also connect General Purpose IO Pins to CMOS devices using 1.8 volt logic. The Preliminary Summary Datasheet http://www.atmel.com/dyn/resources/prod ... /6430s.pdf has figures on pages 16 and 17 with notes that indicate USB is not usable unless the "Main Supply" is greater than 3 volts.

However, those figures use a single power supply for both VDDIO and VDDUTMI. If I supply VDDUTMI with 3.3 volts, and VDDIO with 2.5 or 1.8 volts, will USB and GPIOs both still work?

Thanks