这里使用了CAN1的接口，具体使用MX创建项目就不放了

需要注意的是，由于是最小核心没有CAN的收发模块需要外接一个

STM32核心板接CAN收发模块不需要交叉

/**CAN GPIO Configuration
   PA11     ------> CAN_RX
   PA12     ------> CAN_TX
*/

CAN收发模块的H、L接线不需要交叉

接口的关键代码配置如下：

void MX_CAN_Init(void)
{
  hcan1.Instance = CAN1;
  hcan1.Init.Prescaler = 6;
  hcan1.Init.Mode = CAN_MODE_NORMAL;
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_3TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan1.Init.TimeTriggeredMode = ENABLE;
  hcan1.Init.AutoBusOff = DISABLE;
  hcan1.Init.AutoWakeUp = DISABLE;
  hcan1.Init.AutoRetransmission = DISABLE;
  hcan1.Init.ReceiveFifoLocked = DISABLE;
  hcan1.Init.TransmitFifoPriority = ENABLE;
  if (HAL_CAN_Init(&hcan1) != HAL_OK)
  {
    Error_Handler();
  }
}

HAL_StatusTypeDef CAN_SetFilters(void){
  CAN_FilterTypeDef sFilterConfig;
 
  sFilterConfig.FilterBank = 0;   //chenal 0
  sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;  
  sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT; 
 
	sFilterConfig.FilterIdHigh = 0x0020; 
  sFilterConfig.FilterIdLow = 0x0000;  
  sFilterConfig.FilterMaskIdHigh = 0x0020;   
  sFilterConfig.FilterMaskIdLow = 0x0000;  

  sFilterConfig.FilterFIFOAssignment = CAN_FILTER_FIFO0; 
  sFilterConfig.FilterActivation = CAN_FILTER_ENABLE;   
  sFilterConfig.SlaveStartFilterBank = 0; 
  return HAL_CAN_ConfigFilter(&hcan1, &sFilterConfig);
}


void HAL_CAN_MspInit(CAN_HandleTypeDef* canHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(canHandle->Instance==CAN1)
  {
    /* CAN1 clock enable */
    __HAL_RCC_CAN1_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**CAN GPIO Configuration
    PA11     ------> CAN_RX
    PA12     ------> CAN_TX
    */
    GPIO_InitStruct.Pin = GPIO_PIN_11;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = GPIO_PIN_12;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);


    HAL_NVIC_SetPriority(CAN1_RX0_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(CAN1_RX0_IRQn);
  }
}

最后给出Main主线程里的测试代码

//初始化
	MX_CAN_Init();
	//设置过滤
	if (CAN_SetFilters() == HAL_OK){
		 //开启CAN口
	   HAL_CAN_Start(&hcan1);
	}
	//测试计数
	int Count = 0 ;
	//发包缓存
	uint8_t TxData[8] = {0};
	//发送邮箱
  uint32_t tx_mailbox;
	//数据帧头部结构填充
  CAN_TxHeaderTypeDef CAN_tx;
	CAN_tx.StdId = 0x01;      //使用频道 1 - 0x7FF
	CAN_tx.RTR = CAN_RTR_DATA;
	CAN_tx.IDE = CAN_ID_STD;
	CAN_tx.DLC = 8;           //最大8个字节
	CAN_tx.TransmitGlobalTime = DISABLE;
  //接收数据帧
  CAN_RxHeaderTypeDef CAN_rx;	
  while (1) {
        //计数重置
		if (Count > 255){
			Count = 0;
		}
		//判断空闲
		while (HAL_CAN_GetTxMailboxesFreeLevel(&hcan1) <1){}
		TxData[7] = Count & 0xFF;
        //发送数据
		if (HAL_CAN_AddTxMessage(&hcan1,&CAN_tx,TxData,&tx_mailbox) == HAL_OK){
			//发送成功	
		}	  
        //等待空闲,如果没取走会卡在这里
		while (HAL_CAN_GetTxMailboxesFreeLevel(&hcan1)!= 3){}		    
        HAL_Delay(10);
		//判断是否有数据
		while (HAL_CAN_GetRxFifoFillLevel(&hcan1,CAN_RX_FIFO0) != 0){
            //收数据
			if (HAL_CAN_GetRxMessage(&hcan1,CAN_RX_FIFO0,&CAN_rx,szCache) == HAL_OK){
				//接收成功
			} 
		}
    HAL_Delay(100);
}

需要注意，这里演示的是数据帧的收发，每帧携带数据最大8个字节，超过会被截断