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] << 8) | rxBuffer[2]) / 100.0f;
Elevation = (int16_t)((rxBuffer[3] << 8) | 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);
}
}
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 Configuration:
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 main.c:
/* 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] << 8) | rxBuffer[2]) / 100.0f;
Elevation = (int16_t)((rxBuffer[3] << 8) | 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
* @param 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
* @param 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
* @param 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
* @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 = 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
* @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_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.
* @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 */
I believe it is missing the initialization of the DMA handle structure hdma_usart1_rx, take a look in the example below:
void HAL_USART_MspInit(USART_HandleTypeDef *husart)
{
// Configure these USART pins as alternate function pull-up
/* Your Configuration */
/* USER CODE BEGIN USART2_MspInit 1 */
/* USART1 DMA Init */
hdma_usart1_rx.Instance = DMA1_Channel5;
hdma_usart1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_usart1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_usart1_rx.Init.MemInc = DMA_MINC_ENABLE;
hdma_usart1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
hdma_usart1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
hdma_usart1_rx.Init.Mode = DMA_CIRCULAR;
hdma_usart1_rx.Init.Priority = DMA_PRIORITY_HIGH;
if (HAL_DMA_Init(&hdma_usart1_rx) != HAL_OK)
{
Error_Handler();
}
/* USER CODE END USART2_MspInit 1 */
}
As you are using the HAL library, I recommend you reading in the file stm32f3xx_hal_usart.c the explanation how to use USART HAL Driver.