F280049C CAN function 功能

uint32_t status;

    // Read the CAN-B interrupt status (in the CAN_INT register) to find the
    // cause of the interrupt
    status = CAN_getInterruptCause(CANB_BASE);

    // If the cause is a controller status interrupt, then get the status.
    // During first iteration of every ISR execution, status = 0x8000,
    // which simply means CAN_ES != 0x07.
    if(status == CAN_INT_INT0ID_STATUS)
    {
        // Read the controller status.  This will return a field of status
        // error bits that can indicate various errors.  Error processing
        // is not done in this example for simplicity.  Refer to the
        // API documentation for details about the error status bits.
        // The act of reading this status will clear the interrupt.
        //
        status = CAN_getStatus(CANB_BASE);  // Return CAN_ES value.
        // Now status = 0x00000010, indicating RxOK.

        // Check to see if an error occurred.
        if(((status  & ~(CAN_STATUS_RXOK)) != CAN_STATUS_LEC_MSK) &&
           ((status  & ~(CAN_STATUS_RXOK)) != CAN_STATUS_LEC_NONE))
        {
            // Set a flag to indicate some errors may have occurred.
            errorFlag = 1;
            glblStatus = status;
        }
    }