Hi,
I'm designing USB device which will control ID pin to tell USB host (tablet) whether the USB host should supply 5V on the bus (ID pin shorted to ground) or whether there is externally supplied 5 V on the bus so the host can charge itself (ID pin connected via xx kOhm resistor to ground).
Is there any specification what voltage will USB host use to sense the ID pin? Is that 5 V or 3V3?