stm32 can hal

### STM32 CAN HAL 使用教程

#### 初始化CAN外设
为了初始化STM32上的CAN模块，需调用`HAL_CAN_Init()`函数并配置参数结构体。这涉及到设置波特率、模式和其他必要选项[^1]。

CAN_HandleTypeDef hcan;

void MX_CAN_Init(void) {
    hcan.Instance = CAN1;
    hcan.Init.Prescaler = 16;
    hcan.Init.Mode = CAN_MODE_NORMAL;
    hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
    hcan.Init.TimeSeg1 = CAN_BS1_13TQ;
    hcan.Init.TimeSeg2 = CAN_BS2_2TQ;
    hcan.Init.TimeTriggeredMode = DISABLE;
    hcan.Init.AutoBusOff = DISABLE;
    hcan.Init.AutoWakeUp = DISABLE;
    hcan.Init.AutoRetransmission = ENABLE;
    hcan.Init.ReceiveFifoLocked = DISABLE;
    hcan.Init.TransmitFifoPriority = DISABLE;
    
    if (HAL_CAN_Init(&hcan) != HAL_OK) {
        Error_Handler();
    }
}

#### 配置过滤器
通过配置接收滤波器来决定哪些消息可以被接收到。此过程涉及创建一个或多个过滤器实例，并将其添加到CAN控制器中[^2]。

static void CAN_Filter_Config(void){
    CanFilterConfTypeDef canfilterconfig;
  
    canfilterconfig.FilterNumber         = 0; 
    canfilterconfig.FilterMode           = CAN_FILTERMODE_IDMASK;
    canfilterconfig.FilterScale          = CAN_FILTERSCALE_32BIT;
    canfilterconfig.FilterIdHigh         = 0x0000;
    canfilterconfig.FilterIdLow          = 0x0000;
    canfilterconfig.FilterMaskIdHigh     = 0x0000;
    canfilterconfig.FilterMaskIdLow      = 0x0000;
    canfilterconfig.FilterFIFOAssignment = CAN_RX_FIFO0;
    canfilterconfig.FilterActivation     = ENABLE;
    canfilterconfig.BankNumber           = 14;
      
    if(HAL_CAN_ConfigFilter(&hcan, &canfilterconfig)!= HAL_OK){
        /* Filter configuration Error */
        Error_Handler();   
    }     
}

#### 发送数据帧
发送标准格式的数据帧可以通过准备要传输的消息对象并通过`HAL_CAN_AddTxMessage()`函数提交给硬件队列实现[^3]。

uint8_t TxData[] = {0x11, 0x22, 0x33};
CanTxMsgTypeDef pTxMsg;
pTxMsg.StdId = 0x7FF;
pTxMsg.ExtId = 0x01;
pTxMsg.IDE   = CAN_ID_STD;
pTxMsg.RTR   = CAN_RTR_DATA;
pTxMsg.DLC   = sizeof(TxData);
pTxMsg.Data  = TxData;

if (HAL_CAN_AddTxMessage(&hcan, &pTxMsg, NULL) != HAL_OK) {
    // Handle error here...
}

#### 接收数据帧
当有新消息到达时，会触发中断通知应用程序处理这些信息。通常情况下，应该轮询或者等待直到有一个有效载荷可用再读取它[^4]。

while(1){
    uint8_t RxData[8];
    CanRxMsgTypeDef pRxMsg;
    
    if (HAL_CAN_GetRxFifoFillLevel(&hcan, CAN_RX_FIFO0)){
        if (HAL_CAN_GetRxMessage(&hcan, CAN_RX_FIFO0, &pRxMsg, RxData) == HAL_OK){
            // Process received data...
        }
    }
}