we've made an oscilloscope that displays data on PC screen with a software,which is creted on Qt Creator. The MCU software works well on STM32F4 Discovery board,which has STM32F407VG; but when we program STM32F405RG,program loads successfuly, device manager of Windows says "device not recognized", but Windows sees the device. We draw the pcb parts based on ST schematics. What is the difference between 405RG and 407VG? What may be the reason of this problem?