I've been trying to get the USBCDC Processor Expert example to work on the KwikStik-K40 and it seems to have issues. It enumerates successfully and works successfully for the first keystroke (using Hyper Terminal). But the USB controller on the K40 stops responding after this. It only seems to occur on Host to Device USB messages. I've had a similar issue with USB HID on both the K21 and the K40 using the USB Stack.