When I connected a newbie LPC11u68 to USB port,it recognized in windows as an USB mass storage device.When I programmed LPCOPEN HID example by Flash magic to it,after resetting the board,my PC can't recognized it.Only when I pulled down PIO0_1(ISP selection pin)it still recognized as a Mass storage device.??? LPC11u68's Datasheet. I'm using a simple header board with USB port(As i said PC successfully recognized 11u68 as mass storage devices ,then I think there are no hardware fault). Also I'm using LPCXPRESSO IDE v8.0.0,I tried all of the USBD examples in the LPCXPRESSO boards LPCOPEN examples, and they programmed successfully to the chip,also I config a LED to blink. In all of them LED blinked which means MCU is running , but when I connect board to the USB port of my PC,I cant see it in the USB or HID section of my PC's device manager. I don't checked SWD, is LPC11u68 support it? WBR. EDIT:know when I compiled LPC11u68 lpcopen HID examples for the manley 11u68 board ,devices appear in the devices manager but after a second it disappear while I don't disconnect it.