STM32F207VCT6 COM Port Enumerates

[AKluk.1]

Hi,

I am Using STM32F207VCT6 on a project and after loading f/w image am seeing Windows COM Port enumerate on every new device it detects. VID / PID remain the same..

Any ideas on this??

[TDK]

Can you explain what you mean? You're plugging in different boards and getting a different COM port each time? That's expected behavior. In addition to the VID/PID, there is a serial number for each device which (per the USB spec) must be unique. ST's implementation uses the UID to generate it.

[Pavel A.]

While debugging, you can remove the "serial number" descriptor from your firmware.

Also, IIRC there's some registry hack that makes Windows ignore these "serial numbers". You can ask on the Microsoft forums whether Windows 10 still has it.

-- pa

[AKluk.1]

@TDK​ , @Pavel A.​ 

Thank you for the quick answers.

I assumed, incorrectly, that Windows would treat them as the same device based on PID / VID. That makes sense being it is using serial number, and causing drivers to be installed for each new device.

I found a possible registry hack for Windows 10 here: http://paldan.altervista.org/windows-usb-com-ports-proliferation-workaround-with-xhci/

I will give this a try and see if it resolves my issue.