Putty not receiving Data from STM32F303ZE microcontroller

[Athandile]

Hello all.

I'm trying to write a simple message via UART to Putty using stm32f303ze microcontroller. I'm using USART2, via ST-link. All the configurations have been confirmed (baud rate, COM port, bits, etc.) And they are right. I even tried using the STM32 Cube IDE Terminal with no luck. Now I'm not sure if the problem is the UART I'm using, or I'm doing something wrong in the code.

Also I'm not sure about the UART that support VCP in STM32F303ZE microcontrollers. However I tried all the USART, and the were no response in the Terminals.

Below is the simple message I'm trying to send and the full code.

/* USER CODE BEGIN Header */

/**

  ******************************************************************************

  * @file : main.c

  * @brief : Main program body

  ******************************************************************************

  * @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 "main.h"

/* Private includes ----------------------------------------------------------*/

/* USER CODE BEGIN Includes */

#include <string.h>

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/

/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/

/* USER CODE BEGIN PD */

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/

/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/

void SystemClock_Config(void);

static void MX_GPIO_Init(void);

static void MX_USART2_UART_Init(void);

/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/**

  * @brief The application entry point.

  * @retval int

  */

int main(void)

{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */

  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */

  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */

  MX_GPIO_Init();

  MX_USART2_UART_Init();

  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */

  /* USER CODE BEGIN WHILE */

  while (1)

  {

    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */

  char msg[] = "UART test OK\r\n";

  HAL_UART_Transmit(&huart2, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY);

  HAL_Delay(1000);

  }

  /* USER CODE END 3 */

}

/**

  * @brief System Clock Configuration

  * @retval None

  */

void SystemClock_Config(void)

{

  RCC_OscInitTypeDef RCC_OscInitStruct = {0};

  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

  /** Initializes the RCC Oscillators according to the specified parameters

  * in the RCC_OscInitTypeDef structure.

  */

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;

  RCC_OscInitStruct.HSIState = RCC_HSI_ON;

  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;

  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;

  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

  {

    Error_Handler();

  }

  /** Initializes the CPU, AHB and APB buses clocks

  */

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;

  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)

  {

    Error_Handler();

  }

  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART2;

  PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;

  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)

  {

    Error_Handler();

  }

}

/**

  * @brief USART2 Initialization Function

  * @PAram None

  * @retval None

  */

static void MX_USART2_UART_Init(void)

{

  /* USER CODE BEGIN USART2_Init 0 */

  /* USER CODE END USART2_Init 0 */

  /* USER CODE BEGIN USART2_Init 1 */

  /* USER CODE END USART2_Init 1 */

  huart2.Instance = USART2;

  huart2.Init.BaudRate = 115200;

  huart2.Init.WordLength = UART_WORDLENGTH_8B;

  huart2.Init.StopBits = UART_STOPBITS_1;

  huart2.Init.Parity = UART_PARITY_NONE;

  huart2.Init.Mode = UART_MODE_TX_RX;

  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;

  huart2.Init.OverSampling = UART_OVERSAMPLING_16;

  huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;

  huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;

  if (HAL_UART_Init(&huart2) != HAL_OK)

  {

    Error_Handler();

  }

  /* USER CODE BEGIN USART2_Init 2 */

  /* USER CODE END USART2_Init 2 */

}

/**

  * @brief GPIO Initialization Function

  * @PAram None

  * @retval None

  */

static void MX_GPIO_Init(void)

{

  /* USER CODE BEGIN MX_GPIO_Init_1 */

  /* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */

  __HAL_RCC_GPIOA_CLK_ENABLE();

  /* USER CODE BEGIN MX_GPIO_Init_2 */

  /* USER CODE END MX_GPIO_Init_2 */

}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**

  * @brief This function is executed in case of error occurrence.

  * @retval None

  */

void Error_Handler(void)

{

  /* USER CODE BEGIN Error_Handler_Debug */

  /* User can add his own implementation to report the HAL error return state */

  __disable_irq();

  while (1)

  {

  }

  /* USER CODE END Error_Handler_Debug */

}

#ifdef USE_FULL_ASSERT

/**

  * @brief Reports the name of the source file and the source line number

  * where the assert_param error has occurred.

  * @PAram file: pointer to the source file name

  * @PAram line: assert_param error line source number

  * @retval None

  */

void assert_failed(uint8_t *file, uint32_t line)

{

  /* USER CODE BEGIN 6 */

  /* User can add his own implementation to report the file name and line number,

     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* USER CODE END 6 */

}

#endif /* USE_FULL_ASSERT */

[TDK]

Is the the NUCLEO-F303RE board? Are you trying to use the ST-Link's VCP? The VCP is connected to USART3 over PD8/PD9 by default.