MCU_STM32CUBEMX配置生成CAN2的初始化代码的修改

备注一个STM32CUBEMX配置CAN2的遗忘点。

STM32F105/107（405/407）有两个CAN，一般我们两个都会用起来，用STM32CubeMX配置好后，有一个经常容易忘记的地方就是SlaveStartFilterBank这个参数。这里他是最重要的和hcan1不一致的地方，

    CAN2_FilerConf.SlaveStartFilterBank = 14;

这一句必须开启，否则CAN2只能发送数据，无法接收到数据。

这个参数其实设置的是CAN_FMR_CAN2SB（参考《RM0008 24.9.4 CAN filter registers》）

摘录其中比较重要的两句如下，

CAN filter master register (CAN_FMR)
Bits 13:8 CAN2SB[5:0]: CAN2 start bank
These bits are set and cleared by software. They define the start bank for the CAN2 interface (Slave) in the range 0 to 27.

Note:
When CAN2SB[5:0] = 28d, all the filters to CAN1 can be used.
When CAN2SB[5:0] is set to 0, no filters are assigned to CAN1.

红色这两句的意思是：
如果CAN2SB=28，就表示28个过滤器全部分配给CAN1，因为CAN2从28开始，而序号从28开始的过滤器不存在，所以全部28个过滤器都分配给了CAN1。
如果CAN2SB=0，就表示28个过滤器全部分配给CAN2，因为最小序号0的过滤器分配给了CAN2，后续也只能连续地分配给CAN2。

STM32CUBEMX生成代码后，修改后如下，

/**
  * @brief CAN1 Initialization Function
  * @param None
  * @retval None
  */
static void MX_CAN1_Init(void)
{

  /* USER CODE BEGIN CAN1_Init 0 */
	HAL_StatusTypeDef HAL_Status;
	// NOTE:
    //Prescaler = 4;                    ==> APB1.36M/4 = 9M (original=16)
    //Mode = CAN_MODE_LOOPBACK;         ==> CAN_MODE_NORMAL; //CAN_MODE_LOOPBACK
    //CAN_BS1.2_9TQ/ = CAN_BS1.2_9.8TQ; ==> BaudRate = 9M/(1+9+8) = 500K
  /* USER CODE END CAN1_Init 0 */

  /* USER CODE BEGIN CAN1_Init 1 */

  /* USER CODE END CAN1_Init 1 */
  hcan1.Instance = CAN1;
  hcan1.Init.Prescaler = 4;
  hcan1.Init.Mode = CAN_MODE_NORMAL;  //CAN_MODE_LOOPBACK
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_9TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_8TQ;
  hcan1.Init.TimeTriggeredMode = DISABLE;
  hcan1.Init.AutoBusOff = DISABLE;
  hcan1.Init.AutoWakeUp = DISABLE;
  hcan1.Init.AutoRetransmission = DISABLE;
  hcan1.Init.ReceiveFifoLocked = DISABLE;
  hcan1.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN1_Init 2 */
	// added bymc
    // add filter_0 to can_1
	CAN_Filter.FilterBank = 0;	                    
	CAN_Filter.FilterMode = CAN_FILTERMODE_IDMASK; 	
	CAN_Filter.FilterScale= CAN_FILTERSCALE_32BIT; 	// 32BIT WIDTH
	CAN_Filter.FilterIdHigh = 0x0000;	            // 32BIT ID
	CAN_Filter.FilterIdLow  = 0x0000;
	CAN_Filter.FilterMaskIdHigh = 0x0000;           // 32BIT MASK
	CAN_Filter.FilterMaskIdLow  = 0x0000;
	CAN_Filter.FilterFIFOAssignment = CAN_FILTER_FIFO0;  //filter_0 -->  FIFO0
    CAN_Filter.FilterActivation = ENABLE;           // NOTE: deactivate it if not used!
	if( HAL_OK != HAL_CAN_ConfigFilter(&hcan1, &CAN_Filter))
	{
		Error_Handler();
	}

	HAL_Status = HAL_CAN_Start(&hcan1); 
	if(HAL_Status!=HAL_OK){
		Error_Handler();
	}	

	// Activate CAN RX notification (HERE WE attach FIFO0 to CAN1) called "CAN0" in manual
	if (HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
	{    
		Error_Handler();
	}

	// Activate CAN TX notification
	if (HAL_CAN_ActivateNotification(&hcan1, CAN_IT_TX_MAILBOX_EMPTY) != HAL_OK)
	{
		Error_Handler();
	}	
	
	// end added bymc

  /* USER CODE END CAN1_Init 2 */

}

/**
  * @brief CAN2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_CAN2_Init(void)
{

  /* USER CODE BEGIN CAN2_Init 0 */
	HAL_StatusTypeDef HAL_Status;
  /* USER CODE END CAN2_Init 0 */

  /* USER CODE BEGIN CAN2_Init 1 */

  /* USER CODE END CAN2_Init 1 */
  hcan2.Instance = CAN2;
  hcan2.Init.Prescaler = 4;
  hcan2.Init.Mode = CAN_MODE_NORMAL;
  hcan2.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan2.Init.TimeSeg1 = CAN_BS1_9TQ;
  hcan2.Init.TimeSeg2 = CAN_BS2_8TQ;
  hcan2.Init.TimeTriggeredMode = DISABLE;
  hcan2.Init.AutoBusOff = DISABLE;
  hcan2.Init.AutoWakeUp = DISABLE;
  hcan2.Init.AutoRetransmission = DISABLE;
  hcan2.Init.ReceiveFifoLocked = DISABLE;
  hcan2.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN2_Init 2 */
	// added bymc
	// add filter_0 to can_1
	CAN_Filter.FilterBank = 14;	                    // <=27       
	CAN_Filter.FilterMode = CAN_FILTERMODE_IDMASK; 	
	CAN_Filter.FilterScale= CAN_FILTERSCALE_32BIT; 	// 32BIT WIDTH
	CAN_Filter.FilterIdHigh = 0x0000;	            // 32BIT ID
	CAN_Filter.FilterIdLow  = 0x0000;
	CAN_Filter.FilterMaskIdHigh = 0x0000;           // 32BIT MASK
	CAN_Filter.FilterMaskIdLow  = 0x0000;
	CAN_Filter.FilterFIFOAssignment = CAN_FILTER_FIFO1;  //filter_0 -->  FIFO0
	CAN_Filter.FilterActivation = ENABLE;
	CAN_Filter.SlaveStartFilterBank = 14;
	if( HAL_OK != HAL_CAN_ConfigFilter(&hcan2, &CAN_Filter))
	{
		Error_Handler();
	}

	HAL_Status = HAL_CAN_Start(&hcan2); 
	if(HAL_Status!=HAL_OK){
		Error_Handler();
	}	

	// Activate CAN RX notification 
	if (HAL_CAN_ActivateNotification(&hcan2, CAN_IT_RX_FIFO1_MSG_PENDING) != HAL_OK)
	{    
		Error_Handler();
	}

	// Activate CAN TX notification
	if (HAL_CAN_ActivateNotification(&hcan2, CAN_IT_TX_MAILBOX_EMPTY) != HAL_OK)
	{
		Error_Handler();
	}

	// end added bymc

  /* USER CODE END CAN2_Init 2 */

}