STM32 USB CDC problem

[mh2]

Posted on May 30, 2017 at 10:07

hi everybody

I'm using stm32l151 and I want to use usb peripheral in cdc mode. I used stm32 cubeMx to generate the project.

when I connect the boar to PC, I can see the VCP in device manager.however I can't sen any data to PC. The function CDC_Transmit_FS() always return USBD_BUSY.

can anyone help me?

Here is my code:

while (1) { CDC_Transmit_FS(Buffer, 6); HAL_Delay(2000); }

I only added the above code to the project created by STM32cubeMX but it didn't work.

Thanks

[Imen.D]

Posted on May 30, 2017 at 12:51

Hi

Hosseinzadeh.Mohamma

,

Are you using CDC example from CubeL1 package ?

You can start with a working 'CDC_Standalone' example available under STM32CubeL1 v1.7.0 and get inspired from the functions used todevelop your application.

Imen

[mh2]

Posted on May 30, 2017 at 13:03

Hi Imen

Thanks for your attention.

I don't use example project. I created a project using STM32CubeMX and then, I just used the function CDC_Transmit_FS() to send the word 'hello' to the PC, as in the example project of

STM32CubeL1 v1.6.0

. I checked in debug mode, and I understood that the first time

C

DC_Transmit_FS is called it does not return USBD_BUSY, but after that, it return USBD_BUSY.

I think that the transmission of the data, didn't complete.

[mh2 · Accepted solution]

Posted on May 31, 2017 at 08:37

I found the problem. It was my new terminal monitor software I used to monitor the serial port. it doesn't monitor the serial port unless the port to be read by a software. It just monitor when the port was opened by another software.

Thanks