1.STM32CubeMX配置

（1）配置SYS

（2）配置RCC

（3）配置串口，此处我用的是串口4，其他串口也是一样的

（4）配置DMA，将串口4的TX和RX添加到DMA中

（5）到这里就全部配置好了，生成代码即可

2.代码编写

（1）先定义一个数组用于存储串口接收的数据。

uint8_t buffer[10]={0};

（2）打开DMA接收和开启空闲中断

HAL_UART_Receive_DMA(&huart4,buffer,5);      //打开串口DMA接收，此处是接收5个数据，存入到buffer这个数组中
__HAL_UART_ENABLE_IT(&huart4,UART_IT_IDLE);   //开启空闲中断，进入空闲就打开中断

（3）在串口中断函数中编写相关功能代码

注意：__HAL_DMA_GET_COUNTER函数获取DMA中未传输的数据个数，所以要计算DMA接收到了多少个数，需要用定义接收的数组大小减去该函数返回值。

void USART3_4_IRQHandler(void)
{
  /* USER CODE BEGIN USART3_4_IRQn 0 */
    if(__HAL_UART_GET_FLAG(&huart4,UART_FLAG_IDLE) != RESET) //进入空闲状态触发当前中断
    {
        __HAL_UART_CLEAR_IDLEFLAG(&huart4); //清除空闲中断标志位
        HAL_UART_DMAStop(&huart4);  //停止DMA，进入一次空闲中断表示DMA传输完成
        uint8_t len = 10 - __HAL_DMA_GET_COUNTER(huart4.hdmarx); //实际上接收到的数据
        HAL_UART_Transmit_DMA(&huart4,buffer,len); //发送数据到串口
        HAL_UART_Receive_DMA(&huart4,buffer, 5);    //打开DMA再一次接收数据
    }
  /* USER CODE END USART3_4_IRQn 0 */
  HAL_UART_IRQHandler(&huart4);
  /* USER CODE BEGIN USART3_4_IRQn 1 */

  /* USER CODE END USART3_4_IRQn 1 */
}

（4）贴出main.c全部代码

/* 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"
#include "dma.h"
#include "usart.h"
#include "gpio.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 */

/* USER CODE END PD */

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

/* USER CODE END PM */

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

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
uint8_t buffer[10]={0};

/**
  * @brief This function handles USART3 and USART4 interrupts.
  */
void USART3_4_IRQHandler(void)
{
  /* USER CODE BEGIN USART3_4_IRQn 0 */
    if(__HAL_UART_GET_FLAG(&huart4,UART_FLAG_IDLE) != RESET) //进入空闲状态触发当前中断
    {
        __HAL_UART_CLEAR_IDLEFLAG(&huart4); //清除空闲中断标志位
        HAL_UART_DMAStop(&huart4);  //停止DMA，进入一次空闲中断表示DMA传输完成
        uint8_t len = 10 - __HAL_DMA_GET_COUNTER(huart4.hdmarx); //实际上接收到的数据
        HAL_UART_Transmit_DMA(&huart4,buffer,len); //发送数据到串口
        HAL_UART_Receive_DMA(&huart4,buffer, 5);    //打开DMA再一次接收数据
    }
  /* USER CODE END USART3_4_IRQn 0 */
  HAL_UART_IRQHandler(&huart4);
  /* USER CODE BEGIN USART3_4_IRQn 1 */

  /* USER CODE END USART3_4_IRQn 1 */
}


/* 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_USART4_UART_Init();
  /* USER CODE BEGIN 2 */
  
    HAL_UART_Receive_DMA(&huart4,buffer,5);      //打开串口DMA接收，此处是接收5个数据，存入到buffer这个数组中
    __HAL_UART_ENABLE_IT(&huart4,UART_IT_IDLE);   //开启空闲中断，进入空闲就打开中断

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* 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};

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

  /** 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.HSIDiv = RCC_HSI_DIV1;
  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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
}

/* 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 */

3.实现效果

串口发送什么数据就接收到什么数据。