my leonardo can not connect my pc, when at first connect the USB, my computer can find the serial port, 30 more seconds later,my PC notify me an unrecognizible USB,; I use different PC and OS(win XP and win 7);I doubt that the upload software prevents the USB from communicate. please help me
ha! I have solved the problem! this must be arduino bug!!!!
I open the develop environment, reset the board on hand; then upload a example piece at once ;try once more, and the board normal!!
restart the board, and my PC can find the driver and not retrieve any more!
so I think my software piece uploaded can prevent board from USB commuicating. this is arduino bug!!
so, some uploaded program in arduino board can prevent PC from USB driver installation and connection.
I do not understand why