Nucleo-H743ZI Virtual Com Port Problem

[Scott Gravenhorst]

Posted on June 03, 2018 at 21:53

I've used the VCP with a ST32F746 Discovery board, which worked without problems.

I now have a Nucleo-H743ZI and I cannot get it to work.

I use Windows 7

The virtual com port shows up in device manager as COM8.  I can open COM8 with PuTTY, but the application running in the board appears not to send anything.  When I remove the USB plug, device manager shows COM8 disappears and when I plug it in, COM8 shows up again.

In the application, I am using USART3 as described in the Nucleo-144 manual.  I send data using the HAL_UART_Transmit() function with the handle address of &huart3.

I know the code is running because the loop sends data and a 200 mSec HAL_Delay() with a LED toggle in the loop.  The LED toggles, so I can see that the program is running.  Just no data makes it to the PuTTY screen.

The files for the project were generated as a makefile project with STM32CubeMX with my code added into main where the 'infinite loop' section for user code is.  I've checked the board jumpers (which are default) and everything looks correct.  There is nothing connected to either the Arduino connector nor the ST Zio/Morpho connector.

[Tesla DeLorean]

Posted on June 03, 2018 at 22:25

Not using CubeMX, but can confirm that the USART3 PD8/PD9 VCP does work.

Make sure HSE_VALUE in stm32h7xx_hal_conf.h is 8000000 and not 25000000

[Scott Gravenhorst · Accepted solution]

Posted on June 03, 2018 at 22:38

Thanks Clive

I've regenerated the project and it's working.  No idea why.

Ok - found it.  STM32CubeMX wrongly assigned USART3 to pins PB10 and PB11 (these are the CubeMX defaults).  The pins used on the board are PD8 and PD9.  When I generated the new project, I corrected the pin map by selecting PD8 and PD9 as USART3 pins - and now it works.

[Tesla DeLorean]

Posted on June 03, 2018 at 22:48

Glitch in the matrix I suppose.

https://community.st.com/0D50X00009XkgXeSAJ