This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

USB Device: Custom Class

Hi all

I try to implement an USB Device with CMSIS on my Hardware. But I'm not able to connect it to Windows. Means, my device does not appear in the device manager of the Windows. My question is: what do I have to do, that my device will recognized by Windows?

I have a STM32L4 Microcontoller with USB Device. I have configured the USB with the Run-Time Environment.

And in my Project I'm using USB Device Custom Class from the MDK Middleware.

My start code of the USB Initializing is as follows:

Both, USBD_Initialize() and USBD_Connect() return "usbOK". But USBD_Configured() returns false. What do I have to do, that this function returns true, or in the other way: why returns USBD_Configured() false? Is this the reason my device didn't connect to Windows? What is the right way to implement USB that a connection is possible?

For additional Info: also the test program WinUSB_Test.exe does not recognize the device.

Thanks for your help.


  • It's unbelievable! I did not realize that I have to enable the USB-Power (VDDUSB) in the POWER CONTROL REGISTER 2. And now I can see activity on the USB-Line but USBD_Connect() fails. Windows device manager shows as follows:

    Sorry, in German. Means: Unknown Device (Error requesting a device description). What do I have to do that it gets the right description?