STM32 HAL Driver

HAL_StatusTypeDef HAL_CAN_Transmit_IT(CAN_HandleTypeDef* hcan)
{
  uint32_t transmitmailbox = CAN_TXSTATUS_NOMAILBOX;

  /* Check the parameters */
  assert_param(IS_CAN_IDTYPE(hcan->pTxMsg->IDE));
  assert_param(IS_CAN_RTR(hcan->pTxMsg->RTR));
  assert_param(IS_CAN_DLC(hcan->pTxMsg->DLC));

  if((hcan->State == HAL_CAN_STATE_READY) || (hcan->State == HAL_CAN_STATE_BUSY_RX))
  {
    /* Process Locked */
    __HAL_LOCK(hcan);

    /* Select one empty transmit mailbox */
    if((hcan->Instance->TSR&CAN_TSR_TME0) == CAN_TSR_TME0)
    {
      transmitmailbox = 0;
    }
    else if((hcan->Instance->TSR&CAN_TSR_TME1) == CAN_TSR_TME1)
    {
      transmitmailbox = 1;
    }
    else if((hcan->Instance->TSR&CAN_TSR_TME2) == CAN_TSR_TME2)
    {
      transmitmailbox = 2;
    }

    if(transmitmailbox != CAN_TXSTATUS_NOMAILBOX)
    {
      /* Set up the Id */
      hcan->Instance->sTxMailBox[transmitmailbox].TIR &= CAN_TI0R_TXRQ;
      if(hcan->pTxMsg->IDE == CAN_ID_STD)
      {
        assert_param(IS_CAN_STDID(hcan->pTxMsg->StdId));
        hcan->Instance->sTxMailBox[transmitmailbox].TIR |= ((hcan->pTxMsg->StdId << 21) | \
                                                  hcan->pTxMsg->RTR);
      }
      else
      {
        assert_param(IS_CAN_EXTID(hcan->pTxMsg->ExtId));
        hcan->Instance->sTxMailBox[transmitmailbox].TIR |= ((hcan->pTxMsg->ExtId << 3) | \
                                                  hcan->pTxMsg->IDE | \
                                                  hcan->pTxMsg->RTR);
      }

      /* Set up the DLC */
      hcan->pTxMsg->DLC &= (uint8_t)0x0000000F;
      hcan->Instance->sTxMailBox[transmitmailbox].TDTR &= (uint32_t)0xFFFFFFF0;
      hcan->Instance->sTxMailBox[transmitmailbox].TDTR |= hcan->pTxMsg->DLC;

      /* Set up the data field */
      hcan->Instance->sTxMailBox[transmitmailbox].TDLR = (((uint32_t)hcan->pTxMsg->Data[3] << 24) |
                                             ((uint32_t)hcan->pTxMsg->Data[2] << 16) |
                                             ((uint32_t)hcan->pTxMsg->Data[1] << 8) |
                                             ((uint32_t)hcan->pTxMsg->Data[0]));
      hcan->Instance->sTxMailBox[transmitmailbox].TDHR = (((uint32_t)hcan->pTxMsg->Data[7] << 24) |
                                             ((uint32_t)hcan->pTxMsg->Data[6] << 16) |
                                             ((uint32_t)hcan->pTxMsg->Data[5] << 8) |
                                             ((uint32_t)hcan->pTxMsg->Data[4]));

      if(hcan->State == HAL_CAN_STATE_BUSY_RX)
      {
        /* Change CAN state */
        hcan->State = HAL_CAN_STATE_BUSY_TX_RX;
      }
      else
      {
        /* Change CAN state */
        hcan->State = HAL_CAN_STATE_BUSY_TX;
      }

      /* Set CAN error code to none */
      hcan->ErrorCode = HAL_CAN_ERROR_NONE;

      /* Process Unlocked */
      __HAL_UNLOCK(hcan);

      /* Enable interrupts: */
      /*  - Enable Error warning Interrupt */
      /*  - Enable Error passive Interrupt */
      /*  - Enable Bus-off Interrupt */
      /*  - Enable Last error code Interrupt */
      /*  - Enable Error Interrupt */
      /*  - Enable Transmit mailbox empty Interrupt */
      __HAL_CAN_ENABLE_IT(hcan, CAN_IT_EWG |
                                CAN_IT_EPV |
                                CAN_IT_BOF |
                                CAN_IT_LEC |
                                CAN_IT_ERR |
                                CAN_IT_TME  );

      /* Request transmission */
      hcan->Instance->sTxMailBox[transmitmailbox].TIR |= CAN_TI0R_TXRQ;
    }
  }
  else
  {
    return HAL_BUSY;
  }

  return HAL_OK;
}