USART communication protocol

[Simontom]

Hi, I’m programming on stm32cubeide and I’m using a H755ZI-Q microcontroller.
I have a small problem with serial communication:
Through usart, I try to display the data of EVERY project on putty.
But I have several problems: the communication is only successful through USART3, using as active the "default" PINs like TX and RX, that is PD8 and PD9.
So this happens: with these two pins configured print, but with other pins (such as PB10 and PB11 which from the datasheet have configuration USART3_TX and USART3_RX) on putty no printing takes place.
Also with all other USART/UART, printing does not take place.
Can you help me? I could make a mistake or is there a function to be coded in order for the communication to take place?

Simon.

[Andrew Neil]

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@Simontom wrote:

you agree that in the schematic, PD8 and PD9 are in that configuration, but in fact the problem is not them, these two pins work correctly.

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The schematic shows that PD8,9 are connected to the ST-Link's VCP - so that's how stuff reaches PuTTY (or whatever) on your PC.

Conversely, that shows you that other pins (eg, PB10,11) are not connected to the ST-Link's VCP - so they will not reach that VCP and, thus, will not reach your PC.

So those pins are also working correctly!

You have two options:

1. Re-wire the board so that other pins (eg, PB10,11 instead of PD8,9) do reach the VCP;
2. Get another VCP device, and connect that to the other pins (eg, PB10,11).

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@Simontom wrote:

 correct me if I’m wrong, but in the diagram where all pins are represented, these are not there.

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Probably, they are not connected anywhere else because they are connected to the ST-Link.

You could check in the schematics to see exactly where they connect.

[Simontom]

@Andrew Neil @Tesla DeLorean 

Hi guys, thank you very much for your answers, slowly thanks to you I’m starting to understand how to solve my problem, at least theoretically.
It may be that in order to actually work the pin connection through a cable of this https://www.amazon.it/dp/B08T24NML9  Because I already have it at my disposal and if it was the required hardware I could immediately start studying the connections to be made.
Best regards.

Simon.

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Link edited to remove tracking garbage

[Andrew Neil · Accepted solution]

Yes, that should do the trick.

Make sure that you set it for 3.3V