Nucleo-L552ZE USART3 to both a terminal and SerialPort

[namuniu]

I'm having an issue with connecting my Nucleo board STM32L552ZE-Q via USART3 to both a terminal and SerialPort. I configured the timer and USART3, but I'm not getting any output on the terminal or in SerialPlot. I’m not sure where the error might be. Can anyone provide guidance or troubleshooting steps?

[Andrew Neil]

Welcome to the forum.

You need to give some more detail for people to be able to understand your situation - see:

How to write your question to maximize your chances to find a solution

 

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@namuniu wrote:

connecting my Nucleo board STM32L552ZE-Q via USART3 to both a terminal and SerialPort.

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Not sure what you mean by that? A diagram could be clearer.

 

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@namuniu wrote:

 I configured the timer and USART3, 

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Take one step at a time - just get the UART working before adding a timer.

https://community.st.com/t5/stm32-mcus/implementing-uart-receive-and-transmit-functions-on-an-stm32/ta-p/694926?search-action-id=44987199767&search-result-uid=694926

 

https://wiki.st.com/stm32mcu/wiki/Getting_started_with_UART 

 

https://wiki.st.com/stm32mcu/wiki/STM32StepByStep:Step3_Introduction_to_the_UART 

 

PS:

Note that, by default, USART3 is not connected to the ST-Link's Virtual COM Port:

https://www.st.com/resource/en/user_manual/um2581-stm32l5-nucleo144-board-mb1361-stmicroelectronics.pdf#page=26

[namuniu]

I need to configure the UART on my Nucleo board to cyclically send data through its virtual serial port. Additionally, I need to set up a timer that generates an interrupt every 100 ms. In each interrupt, the UART should transmit data to the PC—specifically, a variable whose value ranges from -100 to 100. On the PC side, the data should initially be displayed in a terminal and later visualized as a graph in SerialPlot.


this is my usart.c

/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file usart.c
* @brief This file provides code for the configuration
* of the USART instances.
******************************************************************************
* @attention
*
* Copyright (c) 2025 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "usart.h"

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

UART_HandleTypeDef huart3;

/* USART3 init function */

void MX_USART3_UART_Init(void)
{

/* USER CODE BEGIN USART3_Init 0 */

/* USER CODE END USART3_Init 0 */

/* USER CODE BEGIN USART3_Init 1 */

/* USER CODE END USART3_Init 1 */
huart3.Instance = USART3;
huart3.Init.BaudRate = 115200;
huart3.Init.WordLength = UART_WORDLENGTH_8B;
huart3.Init.StopBits = UART_STOPBITS_1;
huart3.Init.Parity = UART_PARITY_NONE;
huart3.Init.Mode = UART_MODE_TX_RX;
huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart3.Init.OverSampling = UART_OVERSAMPLING_16;
huart3.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart3.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart3.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart3) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetTxFifoThreshold(&huart3, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_SetRxFifoThreshold(&huart3, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
{
Error_Handler();
}
if (HAL_UARTEx_DisableFifoMode(&huart3) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART3_Init 2 */

/* USER CODE END USART3_Init 2 */

}

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

GPIO_InitTypeDef GPIO_InitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
if(uartHandle->Instance==USART3)
{
/* USER CODE BEGIN USART3_MspInit 0 */

/* USER CODE END USART3_MspInit 0 */

/** Initializes the peripherals clock
*/
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART3;
PeriphClkInit.Usart3ClockSelection = RCC_USART3CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}

/* USART3 clock enable */
__HAL_RCC_USART3_CLK_ENABLE();

__HAL_RCC_GPIOD_CLK_ENABLE();
/**USART3 GPIO Configuration
PD8 ------> USART3_TX
PD9 ------> USART3_RX
*/
GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF7_USART3;
HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

/* USART3 interrupt Init */
HAL_NVIC_SetPriority(USART3_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(USART3_IRQn);
/* USER CODE BEGIN USART3_MspInit 1 */

/* USER CODE END USART3_MspInit 1 */
}
}

void HAL_UART_MspDeInit(UART_HandleTypeDef* uartHandle)
{

if(uartHandle->Instance==USART3)
{
/* USER CODE BEGIN USART3_MspDeInit 0 */

/* USER CODE END USART3_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_USART3_CLK_DISABLE();

/**USART3 GPIO Configuration
PD8 ------> USART3_TX
PD9 ------> USART3_RX
*/
HAL_GPIO_DeInit(GPIOD, GPIO_PIN_8|GPIO_PIN_9);

/* USART3 interrupt Deinit */
HAL_NVIC_DisableIRQ(USART3_IRQn);
/* USER CODE BEGIN USART3_MspDeInit 1 */

/* USER CODE END USART3_MspDeInit 1 */
}
}

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

[Andrew Neil]

 

Again, please see How to write your question to maximize your chances to find a solution - and note how to properly post source code.

 

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@namuniu wrote:

I need to configure the UART on my Nucleo board to cyclically send data through its virtual serial port.

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Then you need to use LPUART1 - see the PS to my previous post.

 

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@namuniu wrote:

 Additionally, I need to ...

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Again, first concentrate on just getting the basic UART working.

Don't move on to additional stuff until the basics are working!