[VCP] Virtual Com Port on STM32L4

gravell · ‎2015-08-05

Posted on August 05, 2015 at 12:59

Hello, I am using STM32L4 uC and I'am trying to create a Virtual Com Port. My problem is that computer does not recognize device after running it (I can only see ''Unknown device'' message).

Here is how I configure timer:

PLLM = 1;

PLLN = 36;

PLLP = 7;

PLLQ = 6;

PLLR = 2;

which should give me frequency of 48MHz for USB.

As far as I know the ''Unknown device'' problem is related to wrong timer configuration so there is a question - do I configure timer correctly? If yest then what may cause the problem?

Amel NASRI · ‎2015-08-05

Posted on August 05, 2015 at 17:31

Hi ca.pwl,

Start with a working example in a known hardware in order to deduce what is going wrong in your case.

You may refer to the example under STM32Cube_FW_L4_V0.4.0\Projects\STM32L476G_EVAL\Applications\USB_Device\CDC_Standalone.

-Mayla-

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