I have my Tiva controller perfectly working with USB dot matrix printers. Now I am trying to make it work for the USB laser printers using the same USB library. It is working fine with some laser printers which are old. Then i got a new HP printer and it is not working with it. Same is the problem with one of my Cannon printers. The difference is that new HP printer has 5 interface descriptors as compared to one interface descriptor(i.e. Printer(0x07)) in the old printers. Does that make any difference in the detection of the printer and its working? The USBHCDEvents() is not able to detect a supported device when new printer is connected. I always returns USB_EVENT_UNKNOWN_CONNECTED and then disconnects it. What can be the issue? I thought the USB checks the device class and then loads the corresponding drivers but it is not able to detect it. I checked it on windows PC with USB Analyser, there it seems fine and is returning the class as Printer upon query. It is working fine on Windows PC as well like the old ones. Can someone suggest me any solution for this?