I have a 21369 EZ KIT with a USB Extender board. The example USB code using polling to monitor USB activity. Actually, it will not return from the function "adi_dev_Read()" until a host sends some USB data. I have yet been unsuccessful in modifying the example code so that it is Event or Interrupt driven. Has anyone tackled this before? The USB Extender board uses a PLX Net2272 chip. I'd really like to only service USB when there is an actual USB event, thus freeing up a great deal of processing and DMAing ( the provided PLX device drivers use DMA channel 0).