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DWell.1
DWell.1
Associate
July 27, 2022
Question

B-U585I-IOT02A Discovery Board, USART2 and USART3 Comms

  • July 27, 2022
  • 2 replies
  • 1315 views

I am trying to use the USART's via the CN2 or CN3 connector.

The documentation "um2839-discovery-kit-for-iot-node-with-stm32u5-series-stmicroelectronics.pdf" gives the following pin mappings:

CN2

USART3_TX -> PD8

USART3_RX -> PD9

CN3

USART2_TX -> PA2

USART2_RX ->PA3

When I create a project using STM32CubeIDE (version 1.9.0)

It assigns the following:

USART3_TX -> PA5

USART3_RX -> PA7

USART2_TX -> PD5

USART2_RX -> PD6

What am I to do?

Cheers,

Don

This topic has been closed for replies.

2 replies

DWell.1
DWell.1Author
Associate
July 27, 2022

I have now resolved this issue.

Basically STM32CubeIDE is wrong!

I found a schematic and it confirmed what the user guide stated.

In the file stm32u5xx_hal_msp.c the function HAL_UART_MspInit() is where the pins are assigned to the UART's. I have added code to assign the correct PIN's.

I can now TX data on UART3!

KDJEM.1
KDJEM.1
ST Technical Moderator
August 19, 2022

Hi @DWell.1​ and welcome to the Community :),

Thank you for your contribution.

I think that the USART2 and USART3 Pins are well described in the STM32Cube IDE.

These Pins descriptions are right and in relation with the Datasheet DS13086 REV 6.

So, you can refer to the User Manual UM2839 in the USART2 and USART3 configurations.

Kaouthar

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