I can not see any printf in screen using Tera Term

[rubenles]

I am trying to write something using printf with STM32-nucleo-h743zi board, windows 10. I can run programs that make a led turn on, and make connections via uart and all the things, but when i open tera term or Putty, i can not see any word in there.. I link my nucleo with other stm32  chip to do other stuff and it works via uart, but nothing about writing in Tera term or Putty.

My COM configuration is ok for sure, and i use the same baud that is written in my code.

I just use this method, i saw this tutorial: https://community.st.com/t5/stm32-mcus/how-to-redirect-the-printf-function-to-a-uart-for-debug-messages/ta-p/49865

I saw different videos in youtube and all the people do it in the same way.

I connect my board using USB. It must be simple, but i can't reach this thing...

Any suggestions??

Thank you.

[Peter BENSCH · Accepted solution]

Well, you don't see anything via Putty or Teraterm because you parameterised USART3 correctly (asynch, 115200 Bits/s, etc) but accidentally stumbled over the pin multiplexing. In the STM32H743, PB11/PB10 is unfortunately selected as the default for USART3 RX/TX, but in the NUCLEO-H743ZI (MB1364) PD9/PD8 are connected to T_VCP_RX/_TX via SB12/SB19. So the USART3 permanently writes the data to the TX channel - but you have checked on a different TV channel... 😊

Solution: simply remap the alternative pins for USART3_RX/TX in the CubeMX overview of the STM32H743ZITx as described in UM1718, section 4.45:

To manually remap a function to another pin, follow the sequence below:

1. from the Pinout view, hold down the CTRL key then left-click on the pin and hold: if any pins are possible for relocation, they are highlighted in blue and blinking.
2. drag the function to the target pin.

...i.e. drag them one after the other to PD9/PD8.

Hope that helps?

Regards
/Peter

[rubenles]

That's right, that was the problem, stm32cubemx automatically assigns pins pb11 and pb10..., and i needed pd9 and pd8 as you said...

Hundreds of thanks @Peter BENSCH !!

[Tesla DeLorean]

See also   https://github.com/STMicroelectronics/STM32CubeH7/blob/master/Drivers/BSP/STM32H7xx_Nucleo/stm32h7xx_nucleo.h#L250

[Peter BENSCH]

Always happy to help.

However, you only got the problem because you started with the bare STM32H743ZI. However, as mentioned, it was on a PCB (a NUCLEO) that was already populated, so you would have been better off using the tab Board Selector instead of the tab MCU Selector to create a new project, as this takes the existing wiring into account.

[rubenles]

What is this used for exactly? Thank you

[rubenles]

That is a nice point..., as you said i was choosing my board in the MCU selector and using the board selector tab, i can select the active nucleo with the correct usart 3 pins.

Thank you so much once again!

[Yassine1]

Translator

I had the same issue.

It works welll now thanks a lot