从零开始之stm32之CAN通信

从小白的视角了解并实现简单的STM32F103的CAN通信，直接上手。

一、CAN协议简介

CAN总线上传输的信息称为报文，当总线空闲时任何连接的单元都可以开始发送新的报文，有5种类型的帧：数据帧、遥控帧、错误帧、过载帧、帧间隔。数据帧有两种格式：标准格式和扩展格式主要区别在于ID长度。

二、参数含义和设置

STM32CubeIDE关于CAN的参数设置

1、位时序参数说明和设置

Prescaler：预分频系数，定义CAN单位时钟周期=APB1外设时钟频率/分频系数，取值范围：1 ~ 1024，上述APB频率 = 36MHz。

用打电话的方式，表示设置参数：

参数确定：

1、优先确定Prescaler：

计算 Prescaler = CAN_CLK / (波特率 × (1 + TimeSeg1 + TimeSeg2))，取最接近的整数值。

例如：36MHz目标1Mbps，假设 1+6+2=9Tq → Prescaler = 36MHz/(1MHz×9) = 4。

2、TimeSeg1/TimeSeg2分配：

短距离：TimeSeg1可小（如5~6Tq），TimeSeg2=1~2Tq。

长距离：TimeSeg1需大（如8~12Tq），TimeSeg2=2~4Tq。

规则：TimeSeg1 ≥ TimeSeg2 + SyncJumpWidth。

3、SyncJumpWidth选择：

高速CAN（≥500kbps）：1Tq（严格同步）。

低速/工业CAN（≤250kbps）：2Tq（增强容错）。

4、抗干扰优化：

增大TimeSeg1和SyncJumpWidth可提升稳定性，但会降低波特率。

若通信不稳定，逐步增加TimeSeg1（每次+1Tq）并测试。

2、基本参数说明和设置

参数说明：

3、高级参数设置和说明

测试模式说明

4、开启中断

可以在System Core --> NVIC中设置中断优先等级

三、实际例程

1、CAN初始化

增加接收滤波器，可以用于筛选接收数据，硬件级过滤，可以

1. 降低CPU负担（避免处理无关报文）

2. 提高实时性（仅处理目标数据）

3. 必须配置（否则无法接收数据）

4. 灵活可控（支持掩码/列表两种过滤模式）

/**
 * @brief CAN Initialization Function
 * @param None
 * @retval None
 */
static void MX_CAN_Init(void)
{

  /* USER CODE BEGIN CAN_Init 0 */

  /* USER CODE END CAN_Init 0 */

  /* USER CODE BEGIN CAN_Init 1 */

  /* USER CODE END CAN_Init 1 */
  hcan.Instance = CAN1;
  hcan.Init.Prescaler = 4;
  hcan.Init.Mode = CAN_MODE_LOOPBACK;
  hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan.Init.TimeSeg1 = CAN_BS1_5TQ;
  hcan.Init.TimeSeg2 = CAN_BS2_3TQ;
  hcan.Init.TimeTriggeredMode = DISABLE;
  hcan.Init.AutoBusOff = DISABLE;
  hcan.Init.AutoWakeUp = ENABLE;
  hcan.Init.AutoRetransmission = DISABLE;
  hcan.Init.ReceiveFifoLocked = DISABLE;
  hcan.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN_Init 2 */

  /* USER CODE BEGIN CAN_Init 2 */

  CAN_FilterTypeDef sFilterConfig;
  sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
  sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
  sFilterConfig.FilterIdHigh = 0x0000; // 可以保持为0接收所有ID
  sFilterConfig.FilterIdLow = 0x0000;
  sFilterConfig.FilterMaskIdHigh = 0x0000;
  sFilterConfig.FilterMaskIdLow = 0x0000;
  sFilterConfig.FilterFIFOAssignment = CAN_RX_FIFO0;
  sFilterConfig.FilterBank = 0; // 添加过滤器组号
  sFilterConfig.SlaveStartFilterBank = 14;
  sFilterConfig.FilterActivation = ENABLE;

  HAL_StatusTypeDef state = HAL_CAN_ConfigFilter(&hcan, &sFilterConfig);
  if (state != HAL_OK)
  {
    Error_Handler();
  }

  state = HAL_CAN_Start(&hcan);
  if (state != HAL_OK)
  {
    Error_Handler();
  }

  state = HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);
  if (state != HAL_OK)
  {
    Error_Handler();
  }

  /* USER CODE END CAN_Init 2 */
  /* USER CODE END CAN_Init 2 */
}

关于接收滤波器说明与设置:

2、添加中断回调函数

STM32 HAL库中CAN接收中断的回调函数，当CAN控制器的接收FIFO0（接收缓冲区0）中有新消息到达时，会自动触发此函数。

/* USER CODE BEGIN 4 */

void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *CanHandle)
{
  /* Get RX message */
  if (HAL_CAN_GetRxMessage(CanHandle, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
  {
    /* Reception Error */
    Error_Handler();
  }

  // 接收到的数据：RxData[8]
  // 接收到的ID值：RxHeader.StdId
}

/* USER CODE END 4 */

3、发送数据

将CAN报文放入发送邮箱，由硬件自动发送到总线上

• 非阻塞式发送：函数仅将数据存入CAN控制器的发送邮箱，实际发送由硬件完成，无需CPU持续等待。

    if (HAL_CAN_AddTxMessage(&hcan, &txHeader, TxData, &TxMailbox) != HAL_OK)
    {
      Error_Handler();
    }

4、整个例程

可以通过调试查看接收的数据是否对应发送数据。

/* 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 */

/* 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 ---------------------------------------------------------*/
CAN_HandleTypeDef hcan;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

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

/* USER CODE END PFP */

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

CAN_TxHeaderTypeDef txHeader =
    {
        .StdId = 0x123,
        .ExtId = 0x00,
        .IDE = CAN_ID_STD,
        .RTR = CAN_RTR_DATA,
        .DLC = 8,
        .TransmitGlobalTime = DISABLE};
CAN_RxHeaderTypeDef RxHeader;
uint8_t TxData[8] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08}; // 定义数据
uint8_t RxData[8];
uint32_t TxMailbox;

/* 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_CAN_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 */

    if (HAL_CAN_AddTxMessage(&hcan, &txHeader, TxData, &TxMailbox) != HAL_OK)
    {
      Error_Handler();
    }

    HAL_Delay(2000);

    HAL_GPIO_TogglePin(SYS_LED_GPIO_Port, SYS_LED_Pin);
  }
  /* USER CODE END 3 */
}

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

  /** 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.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  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();
  }
}

/**
 * @brief CAN Initialization Function
 * @param None
 * @retval None
 */
static void MX_CAN_Init(void)
{

  /* USER CODE BEGIN CAN_Init 0 */

  /* USER CODE END CAN_Init 0 */

  /* USER CODE BEGIN CAN_Init 1 */

  /* USER CODE END CAN_Init 1 */
  hcan.Instance = CAN1;
  hcan.Init.Prescaler = 4;
  hcan.Init.Mode = CAN_MODE_LOOPBACK;
  hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan.Init.TimeSeg1 = CAN_BS1_5TQ;
  hcan.Init.TimeSeg2 = CAN_BS2_3TQ;
  hcan.Init.TimeTriggeredMode = DISABLE;
  hcan.Init.AutoBusOff = DISABLE;
  hcan.Init.AutoWakeUp = ENABLE;
  hcan.Init.AutoRetransmission = DISABLE;
  hcan.Init.ReceiveFifoLocked = DISABLE;
  hcan.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN_Init 2 */

  /* USER CODE BEGIN CAN_Init 2 */

  CAN_FilterTypeDef sFilterConfig;
  sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
  sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
  sFilterConfig.FilterIdHigh = 0x0000; // 可以保持为0接收所有ID
  sFilterConfig.FilterIdLow = 0x0000;
  sFilterConfig.FilterMaskIdHigh = 0x0000;
  sFilterConfig.FilterMaskIdLow = 0x0000;
  sFilterConfig.FilterFIFOAssignment = CAN_RX_FIFO0;
  sFilterConfig.FilterBank = 0; // 添加过滤器组号
  sFilterConfig.SlaveStartFilterBank = 14;
  sFilterConfig.FilterActivation = ENABLE;

  HAL_StatusTypeDef state = HAL_CAN_ConfigFilter(&hcan, &sFilterConfig);
  if (state != HAL_OK)
  {
    Error_Handler();
  }

  state = HAL_CAN_Start(&hcan);
  if (state != HAL_OK)
  {
    Error_Handler();
  }

  state = HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);
  if (state != HAL_OK)
  {
    Error_Handler();
  }

  /* USER CODE END CAN_Init 2 */
  /* USER CODE END CAN_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_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(SYS_LED_GPIO_Port, SYS_LED_Pin, GPIO_PIN_SET);

  /*Configure GPIO pin : SYS_LED_Pin */
  GPIO_InitStruct.Pin = SYS_LED_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(SYS_LED_GPIO_Port, &GPIO_InitStruct);

  /* USER CODE BEGIN MX_GPIO_Init_2 */
  /* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *CanHandle)
{
  /* Get RX message */
  if (HAL_CAN_GetRxMessage(CanHandle, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
  {
    /* Reception Error */
    Error_Handler();
  }

  // 接收到的数据：RxData[8]
  // 接收到的ID值：RxHeader.StdId
}

/* 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 */

四、整个通信逻辑

CAN通信关键环节详解

1、发送端逻辑

2. 总线传输

• 广播特性：所有节点同时收到数据，但只有通过过滤的节点会处理。

• 物理层校验：

  • 差分信号（CAN_H/CAN_L）抗干扰

  • 显性电平（0）覆盖隐性电平（1）实现仲裁

3. 接收端逻辑

4. 硬件级校验

5、错误处理机制

6、应用场景建议

• 汽车ECU：严格ID过滤 + CRC校验 + AutoRetransmission

• 工业控制：自定义软件校验 + 长TimeSeg1抗干扰

• 诊断工具：接收所有ID（FilterMask=0） + 软件解析

通过上述机制，CAN总线实现高可靠、实时的分布式通信。