I hoping someone can clarify a statement on page 10 of the Gumstix Overo COM Signals document:

"Like SYSEN, USB_CPEN can be used as an enable line for USB_VBUS; this is done on
several Gumstix expansion boards such as Tobi. However, it is not necessary to gate the
USB_VBUS line; as long as VBUS on the USB connector gets 5V, the USB interface should
work correctly."

The latter part of this statement is what I find a little confusing.  Does it mean that an un-gated VBUS +5V may be present on the Overo USBH_VBUS pin at powerup?  Or, is it simply stating that downstream USB devices don't absolutely need the VBUS signal to be gated (which seems counter-intuitive since this would result in no over-current protection)?

Best Regards,

Dave Billin

Graduate Research Assistant --MS Computer Engineering
University of Idaho
Moscow, Idaho 83844

e-mail: david.billin@vandals.uidaho.edu