STM32 Nucleo F303RE: USART1 DMA not receiving data from GY-25 sensor

[Nicolas3]

I'm working on a project with the STM32 Nucleo F303RE, and I'm using USART1 to receive data from a GY-25 sensor at 9600 bps using DMA. However, I'm not receiving any data through the DMA callback. I’ve verified that the GY-25 is transmitting data, but my HAL_UART_RxCpltCallback is never triggered, and the rxBuffer remains empty. I am using USART2 to communicate with termite. Here is a simplified version of my code:

#define RX_BUFFER_SIZE 8

uint8_t rxBuffer[RX_BUFFER_SIZE] = {0};
float Elevation, Azimuth;
uint8_t imu_updated = 0;

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) {
    if (rxBuffer[0] == 0xAA && rxBuffer[7] == 0x55) {
        Azimuth = (int16_t)((rxBuffer[1] <<  | rxBuffer[2]) / 100.0f;
        Elevation = (int16_t)((rxBuffer[3] <<  | rxBuffer[4]) / 100.0f;
        imu_updated = 1;
    }
    HAL_UART_Receive_DMA(&huart1, rxBuffer, RX_BUFFER_SIZE);
}

int main(void) {
    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    MX_DMA_Init();
    MX_USART1_UART_Init();
    
    // Start UART reception using DMA
    HAL_UART_Receive_DMA(&huart1, rxBuffer, RX_BUFFER_SIZE);
    
    while (1) {
        if (imu_updated) {
            imu_updated = 0;
            // Process azimuth and elevation
        }
        HAL_Delay(100);
    }
}

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 USART 1 initialization:

static void MX_USART1_UART_Init(void) {
    huart1.Instance = USART1;
    huart1.Init.BaudRate = 9600;
    huart1.Init.WordLength = UART_WORDLENGTH_8B;
    huart1.Init.StopBits = UART_STOPBITS_1;
    huart1.Init.Parity = UART_PARITY_NONE;
    huart1.Init.Mode = UART_MODE_TX_RX;
    huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
    huart1.Init.OverSampling = UART_OVERSAMPLING_16;
    if (HAL_UART_Init(&huart1) != HAL_OK) {
        Error_Handler();
    }
}

DMA Initialization:

static void MX_DMA_Init(void) {
    __HAL_RCC_DMA1_CLK_ENABLE();
    
    /* DMA interrupt init */
    HAL_NVIC_SetPriority(DMA1_Channel5_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(DMA1_Channel5_IRQn);
}

Full 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"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "math.h"
#include <stdlib.h>
#include <stdbool.h>

#include "string.h"
#include "stdio.h"
#include "stm32f3xx_hal.h"
#include "stm32f3xx_hal_uart.h"
/* USER CODE END Includes */

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

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define RX_BUFFER_SIZE 8

/* USER CODE END PD */

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

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
TIM_HandleTypeDef htim2;
TIM_HandleTypeDef htim3;

UART_HandleTypeDef huart1;
UART_HandleTypeDef huart2;
DMA_HandleTypeDef hdma_usart1_rx;

/* USER CODE BEGIN PV */
//GY25 variables
uint8_t rxBuffer[RX_BUFFER_SIZE]={0};

float Elevation, Azimuth;

uint8_t imu_updated = 0;

//debug variables
char message[50];  // Buffer to hold the message
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_TIM2_Init(void);
static void MX_TIM3_Init(void);
static void MX_USART1_UART_Init(void);
/* USER CODE BEGIN PFP */
void send_debug_message(const char *message);
//void getAzEli(void);
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

void send_debug_message(const char *message)
{
    HAL_UART_Transmit(&huart2, (uint8_t *)message, strlen(message), HAL_MAX_DELAY);
}
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart){
     if (rxBuffer[0] == 0xAA && rxBuffer[7] == 0x55)
     {
         Azimuth = (int16_t)((rxBuffer[1] <<  | rxBuffer[2]) / 100.0f;
         Elevation = (int16_t)((rxBuffer[3] <<  | rxBuffer[4]) / 100.0f;
         imu_updated = 1;
     }
     HAL_UART_Receive_DMA(&huart1, rxBuffer, RX_BUFFER_SIZE);
     __HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
}




/* 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_DMA_Init();
  MX_USART2_UART_Init();
  MX_TIM2_Init();
  MX_TIM3_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */

//  HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_1);
//  HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_3);

  HAL_UART_Receive_DMA(&huart1, rxBuffer, RX_BUFFER_SIZE);
  __HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
  send_debug_message("Stabilizing...\n");

  HAL_Delay(3000);  // Wait 3 seconds for GY-25 to stabilize
  send_debug_message("Calibrating...\n");

  //GY25 setup
  uint8_t zero_both_axis_cmd[] = {0xA5, 0x54};  // Pitch and roll correction
  HAL_UART_Transmit(&huart1, zero_both_axis_cmd, 2, HAL_MAX_DELAY);
  HAL_Delay(4000);  // Wait for calibration

  uint8_t auto_mode_cmd[] = {0xA5, 0x52};  // Set automatic mode
  HAL_UART_Transmit(&huart1, auto_mode_cmd, 2, HAL_MAX_DELAY);
  send_debug_message("Calibration complete!\n");

  // Start UART reception using DMA


  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
//PWM CODE
      //forwards
//      __HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_1, 30); // 10% duty cycle
//      __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_3, 0);


//      HAL_Delay(10000);
//      __HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_1, 50); // 50% duty cycle
//      HAL_Delay(10000);
//      __HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_1, 100); // 100% duty cycle
//      HAL_Delay(10000);

        //backwards
//      __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_3, 10); // 50% duty cycle
//      HAL_Delay(10000);
//      __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_3, 50); // 50% duty cycle
//      HAL_Delay(10000);
//      __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_3, 100); // 50% duty cycle
//      HAL_Delay(10000);
//

//END PWM

        //GY 25 Code
            if (imu_updated)
            {
              imu_updated = 0;
              snprintf(message, sizeof(message), "Azimuth: %.2f, Elevation: %.2f \n", Azimuth, Elevation);
              send_debug_message(message);

            }
            HAL_Delay(100);  // Adjust delay as needed

    /* USER CODE END WHILE */

    /* 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};
  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_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  RCC_OscInitStruct.PLL.PREDIV = RCC_PREDIV_DIV1;
  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_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1|RCC_PERIPHCLK_USART2
                              |RCC_PERIPHCLK_TIM2|RCC_PERIPHCLK_TIM34;
  PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;
  PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;
  PeriphClkInit.Tim2ClockSelection = RCC_TIM2CLK_HCLK;
  PeriphClkInit.Tim34ClockSelection = RCC_TIM34CLK_HCLK;
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief TIM2 Initialization Function
  *  None
  * @retval None
  */
static void MX_TIM2_Init(void)
{

  /* USER CODE BEGIN TIM2_Init 0 */

  /* USER CODE END TIM2_Init 0 */

  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};

  /* USER CODE BEGIN TIM2_Init 1 */

  /* USER CODE END TIM2_Init 1 */
  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 71;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 99;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_PWM_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.OCMode = TIM_OCMODE_PWM1;
  sConfigOC.Pulse = 0;
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_3) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM2_Init 2 */

  /* USER CODE END TIM2_Init 2 */
  HAL_TIM_MspPostInit(&htim2);

}

/**
  * @brief TIM3 Initialization Function
  *  None
  * @retval None
  */
static void MX_TIM3_Init(void)
{

  /* USER CODE BEGIN TIM3_Init 0 */

  /* USER CODE END TIM3_Init 0 */

  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};

  /* USER CODE BEGIN TIM3_Init 1 */

  /* USER CODE END TIM3_Init 1 */
  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 71;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 99;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_PWM_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.OCMode = TIM_OCMODE_PWM1;
  sConfigOC.Pulse = 0;
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM3_Init 2 */

  /* USER CODE END TIM3_Init 2 */
  HAL_TIM_MspPostInit(&htim3);

}

/**
  * @brief USART1 Initialization Function
  *  None
  * @retval None
  */
static void MX_USART1_UART_Init(void)
{

  /* USER CODE BEGIN USART1_Init 0 */

  /* USER CODE END USART1_Init 0 */

  /* USER CODE BEGIN USART1_Init 1 */

  /* USER CODE END USART1_Init 1 */
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 9600;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART1_Init 2 */

  /* USER CODE END USART1_Init 2 */

}

/**
  * @brief USART2 Initialization Function
  *  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 = 9600;
  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 */

}

/**
  * Enable DMA controller clock
  */
static void MX_DMA_Init(void)
{

  /* DMA controller clock enable */
  __HAL_RCC_DMA1_CLK_ENABLE();

  /* DMA interrupt init */
  /* DMA1_Channel5_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Channel5_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Channel5_IRQn);

}

/**
  * @brief GPIO Initialization Function
  *  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_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOF_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin : B1_Pin */
  GPIO_InitStruct.Pin = B1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(B1_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.
  *   file: pointer to the source file name
  *   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 */

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[Andrew Neil]

---

@Nicolas3 wrote:

I’ve verified that the GY-25 is transmitting data,  

---

How have you verified that this data is actually reaching the STM32's UART?

Does the UART work without DMA ?

[Nicolas3]

It did work without dma, but when I just tried to replicate it, it didnt work and my GY25 module became very hot. Im guessing its a hardware fault then