STM32H745I-DISCO STLink UART Virtual Com Port not outputting

[woozl]

Hello,

I have a STM32H745I-DISCO board that I would like to debug using UART Serial over the STLINK virtual com port. UM2488 Section 6.14 shows this should be connected to USART3.

I have the USART3 peripheral enabled with the following configuration: 

In the main function, I have:

uint8_t buf[32] = "Hello!!"

and:

 while (1)
 {
 HAL_UART_Transmit(&huart3, buf, strlen((char*)buf), HAL_MAX_DELAY);
 HAL_Delay(500);
 }

I have ensured that the STLNK VCP driver is installed, and I see the COM port in my device manager window.

I connect to the port with the following settings in PuTTY:

The terminal connects, but I don't see my output string.

Is there any example UART serial printing code for the H7 that I could look over? If any extra information is needed just let me know.

Thanks!

[Guenael Cadier]

Hello @woozl​ 

Have you configured GPIO associated to USART3 TX and RX ?

According to UM2488, Table 16, it looks like PB10 and PB11 are used.

About available examples for this board, please have a look inside H7 FW package.

I think this UART_WakeUpFromStopUsingFIFO example could help (available on Github, or FW package also available on st.com website).

Regards

[woozl]

Thanks for the reply, the pins have been configured as so:Just tried that example and had no luck either.

[Tesla DeLorean]

Look at the code generated, especially pins and clocks.

Make sure the HSE clock is correctly reflected in HSE_VALUE.

Do it on the CM7 core first.

[woozl]

Switching it to the CM7 core worked for some reason. Thanks!