FAQ: I have a Blackfin based USB application for which I've enabled (unmasked) the Connect and Disconnect interrupts, however, when I plug and unplug the USB cable no interrupt is generated. Why is this?

The USB Connect (CONN_B) and Disconnect (DISCON_BE) interrupts are valid only in host mode, i.e., when the Blackfin USB controller is acting as a host.  These interrupts serve to indicate to the Blackfin USB controller that an external USB device has been connected and/or disconnected.  In device mode these interrupts will not be asserted.