原因：若在接收的時候傳送資料，

傳送中的處理：

hal_can_transmit()中會進行hal_lock(hcan);然後更改can狀態為HAL_CAN_STATE_BUSY_TX相關的。

再談一下接收中的處理，不用多說肯定是在接收中斷國會開啟下一次接收，即hal_can_receive_it();那麼這裡邊又幹了什麼：

  /* Check if CAN state is not busy for RX FIFO0 */
  if((FIFONumber == CAN_FIFO0) && ((hcan->State == HAL_CAN_STATE_BUSY_RX0) ||         \
                                   (hcan->State == HAL_CAN_STATE_BUSY_TX_RX0) ||      \
                                   (hcan->State == HAL_CAN_STATE_BUSY_RX0_RX1) ||     \
                                   (hcan->State == HAL_CAN_STATE_BUSY_TX_RX0_RX1)))
  {
    return HAL_BUSY;
  }

  /* Check if CAN state is not busy for RX FIFO1 */
  if((FIFONumber == CAN_FIFO1) && ((hcan->State == HAL_CAN_STATE_BUSY_RX1) ||         \
                                   (hcan->State == HAL_CAN_STATE_BUSY_TX_RX1) ||      \
                                   (hcan->State == HAL_CAN_STATE_BUSY_RX0_RX1) ||     \
                                   (hcan->State == HAL_CAN_STATE_BUSY_TX_RX0_RX1)))
  {
    return HAL_BUSY;
  }
 

這兒會直接返回，也就是說如果此時處於這些狀態說明一定有執行過hal_lock(), 既然我們返回了那相應的中斷標籤並沒有得到相應的處理。

對比後發現hal_can_transmit和hal_can_receive_it中在lock之後都會執行以下語句

  __HAL_CAN_ENABLE_IT(hcan, CAN_IT_EWG |
                            CAN_IT_EPV |
                            CAN_IT_BOF |
                            CAN_IT_LEC |
                            CAN_IT_ERR |
                            CAN_IT_TME);
 

  /* Process unlocked */
   __HAL_UNLOCK(hcan);

  if(FIFONumber == CAN_FIFO0)
  {
    /* Enable FIFO 0 overrun and message pending Interrupt */
    __HAL_CAN_ENABLE_IT(hcan, CAN_IT_FOV0 | CAN_IT_FMP0);
  }
  else
  {
    /* Enable FIFO 1 overrun and message pending Interrupt */
    __HAL_CAN_ENABLE_IT(hcan, CAN_IT_FOV1 | CAN_IT_FMP1);
  }
 

好，那我們是不是如果hal_can_receive_it（&hcan1）== hal_busy時新增執行以上語句就可以了 ，實現證明是可以的。

那在接收中斷中對果hal_can_receive_it作如下處理：

if( HAL_BUSY == HAL_CAN_Receive_IT(hcanx, CAN_FIFO0))//開啟中斷接收
{
	/* Enable FIFO 0 overrun and message pending Interrupt */
	__HAL_CAN_ENABLE_IT(&hcan1, CAN_IT_FOV0 | CAN_IT_FMP0);
}