USART3 Receive interrupts issue.

[ferdlf]

Hi, I'm using the USART3 on interrupt mode with the STM32F407 chip and I cant figure out why the recive function is not working.
I'm transmiting from a STM32F7 a buffer like this: "$en:X# to the F4 but this buffer never arrives when debugging. I'm sure that the data is transmiting from the F7 but dont know about the reception.

Here's the main code 

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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"
#include "stepper.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define opto ((GPIOB->IDR >> 15) & 1)
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
TIM_HandleTypeDef htim6;

UART_HandleTypeDef huart3;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART3_UART_Init(void);
static void MX_TIM6_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
unsigned char mode = 0, enable = 1;
unsigned char buffer[7];

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	HAL_UART_Receive_IT(&huart3, buffer, 6);
	HAL_GPIO_WritePin(GPIOE, GPIO_PIN_9, GPIO_PIN_SET);
}

/* 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_USART3_UART_Init();
  MX_TIM6_Init();
  /* USER CODE BEGIN 2 */

  

  if(enable)
	  GPIOD->ODR &= ~(1<<11);

  GPIOD->ODR &= ~(1<<10);
/*
  if (opto)
  {
	mode = 1;
	while (opto);
	while (!opto);
	mode = 2;
  }

  else
  {
	mode = 1;
	while (!opto);
	mode = 2;
  }
*/
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */

  while (1)
  {
    /* USER CODE END WHILE */
	HAL_UART_Receive_IT(&huart3, buffer, 6);
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure the main internal regulator output voltage
  */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 8;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  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_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief TIM6 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_TIM6_Init(void)
{

  /* USER CODE BEGIN TIM6_Init 0 */

  /* USER CODE END TIM6_Init 0 */

  TIM_MasterConfigTypeDef sMasterConfig = {0};

  /* USER CODE BEGIN TIM6_Init 1 */

  /* USER CODE END TIM6_Init 1 */
  htim6.Instance = TIM6;
  htim6.Init.Prescaler = 840;
  htim6.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim6.Init.Period = 1000 - 1;
  htim6.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim6) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim6, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM6_Init 2 */

  /* USER CODE END TIM6_Init 2 */

}

/**
  * @brief USART3 Initialization Function
  * @PAram None
  * @retval None
  */
static 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 = 9600;
  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;
  if (HAL_UART_Init(&huart3) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART3_Init 2 */
  
  /* USER CODE END USART3_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOE_CLK_ENABLE();
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOE, CS_I2C_SPI_Pin|GPIO_PIN_9, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(OTG_FS_PowerSwitchOn_GPIO_Port, OTG_FS_PowerSwitchOn_Pin, GPIO_PIN_SET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11|LD4_Pin
                          |LD3_Pin|LD5_Pin|LD6_Pin|Audio_RST_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pins : CS_I2C_SPI_Pin PE9 */
  GPIO_InitStruct.Pin = CS_I2C_SPI_Pin|GPIO_PIN_9;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

  /*Configure GPIO pin : OTG_FS_PowerSwitchOn_Pin */
  GPIO_InitStruct.Pin = OTG_FS_PowerSwitchOn_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(OTG_FS_PowerSwitchOn_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : PDM_OUT_Pin */
  GPIO_InitStruct.Pin = PDM_OUT_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
  HAL_GPIO_Init(PDM_OUT_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : B1_Pin */
  GPIO_InitStruct.Pin = B1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_EVT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : I2S3_WS_Pin */
  GPIO_InitStruct.Pin = I2S3_WS_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF6_SPI3;
  HAL_GPIO_Init(I2S3_WS_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : SPI1_SCK_Pin SPI1_MISO_Pin SPI1_MOSI_Pin */
  GPIO_InitStruct.Pin = SPI1_SCK_Pin|SPI1_MISO_Pin|SPI1_MOSI_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pins : BOOT1_Pin PB15 */
  GPIO_InitStruct.Pin = BOOT1_Pin|GPIO_PIN_15;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : CLK_IN_Pin */
  GPIO_InitStruct.Pin = CLK_IN_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
  HAL_GPIO_Init(CLK_IN_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : PD9 PD10 PD11 LD4_Pin
                           LD3_Pin LD5_Pin LD6_Pin Audio_RST_Pin */
  GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11|LD4_Pin
                          |LD3_Pin|LD5_Pin|LD6_Pin|Audio_RST_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

  /*Configure GPIO pins : I2S3_MCK_Pin I2S3_SCK_Pin I2S3_SD_Pin */
  GPIO_InitStruct.Pin = I2S3_MCK_Pin|I2S3_SCK_Pin|I2S3_SD_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF6_SPI3;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : VBUS_FS_Pin */
  GPIO_InitStruct.Pin = VBUS_FS_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(VBUS_FS_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : OTG_FS_ID_Pin OTG_FS_DM_Pin OTG_FS_DP_Pin */
  GPIO_InitStruct.Pin = OTG_FS_ID_Pin|OTG_FS_DM_Pin|OTG_FS_DP_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF10_OTG_FS;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pin : OTG_FS_OverCurrent_Pin */
  GPIO_InitStruct.Pin = OTG_FS_OverCurrent_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(OTG_FS_OverCurrent_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : Audio_SCL_Pin Audio_SDA_Pin */
  GPIO_InitStruct.Pin = Audio_SCL_Pin|Audio_SDA_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF4_I2C1;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : MEMS_INT2_Pin */
  GPIO_InitStruct.Pin = MEMS_INT2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_EVT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(MEMS_INT2_GPIO_Port, &GPIO_InitStruct);

/* 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 */

[Tesla DeLorean]

Check IRQ Handler

Check for sticky error cases, and function returns. Things like noise, parity, framing and over/under run etc. which you need to clear.

Avoid ploughing blindly forward.

[ferdlf]

I've checked everything but nothing works. I actually don't know how to use the reception mode in UART with this MCU, I don't even know if my code is right. I looked for many videos and blogs for the reception but none of them worked.

[Pavel A.]

Do not keep the UART registers  open in the debugger. Reading them is destructive.

[Karl Yamashita]

Did you enable the NVIC interrupt?

[ferdlf]

I did, in the .ioc file.

[floatsky]

There is something wrong in your code. For example, you should not call HAL_UART_Receive_IT in the main while loop.

Maybe you should look at the example code from ST that shows you how to code with USART in interrupt mode.

[Vahid Ajallooeian]

This is useless, you should enable it by adding __hal_uart_enable_it. That one only makes the handler code, not making it enable.