I am designing a device using the PIC32MX795 processor that will act as a USB host. Since it is a battery operating device, I would prefer to not supply 5 volts all of the time on the USB port (the device will operate off a 3.7v Poly-Lithium battery and use a DC-DC boost converter to generate the 5 volts).
I would like to keep the device powered down as much as possible whenever there is nothing plugged into the USB connector. Is there some way of waking up when someone plugs in a USB device into the connector?
Even if I have to wake up once every second or so for a few milliseconds, that might be acceptable but I would prefer not to have to power up the 5 volts each time.
EDIT: After a device is plugged in, and I get data from it, then after some delay I would like to power it off so that it is not drawing current any more. This will force the user to unplug the device and plug it back in again to read the data again, which is okay.