ST-LINK V2—detected as a USB mass storage device

Question

I have an STM32VLDISCOVERY board that I connected to my Windows PC.

This board has an integrated ST-LINK V2 programmer / debugger based on the STM32F103C8 microcontroller which actually communicates with the PC. But this microcontroller is recognized as a "USB mass storage device". In the Device Manager, it is located under Disk drives/STM32.

If I right-click it and follow Properties/Driver/Driver Details/, no ST drivers are listed. There are only some Windows default drivers used for this device:

Now I disconnect the board.

As stated in the documentation, we have to only install the ST-LINK V2 Windows driver STSW-LINK009 before we connect the board to a PC.

I downloaded the driver, uncompressed it, and ran the stlink_winusb_install.bat script as the administrator. This installs the driver and should enable the PC to communicate with STM32F103C8 as it should.

I connect the board back to the workstation PC, but nothing changes. The board is still treated as a USB mass storage device. In Device Manager it is still located under Disk drives/STM32 and *Properties/Driver/Driver Details/ lists no ST drivers. Again only Windows drivers.

After the drivers were installed and the board connected to the PC (as a USB mass storage device), I tried to flash the newest firmware to the board by using the STSW-LINK007 board firmware update utility which fails to connect to the board:

How can I overcome this problem?

Answer 1

ST-LINK V2-1 implements the USB mass storage interface to allow drag-and-drop programming.

If you must disable the mass storage interface, you can do it via the firmware update. From the TN1235 document:

On ST-LINK/V2-1 boards, it is possible to disable and restore the mass storage interface by means of the STLinkUpgrade applications (refer to Figure 1)