TMS320F280049C: 程序发送问题

是的 用的例程 为什么屏蔽自测模式后 就不能正常发送了

   for(;;)
    {
        //
        // Check the error flag to see if errors occurred
        //
        //if(errorFlag)
       //{
            //asm("   ESTOP0");
        //}
        DEVICE_DELAY_US(250000);
        //
        // Verify that the number of transmitted messages equal the number of
        // messages received before sending a new message
        //
       // if(txMsgCount == rxMsgCount)
       // {
            CAN_sendMessage(CANA_BASE, TX_MSG_OBJ_ID, MSG_DATA_LENGTH,
                            txMsgData);
       // }
       // else
      // {
        //    errorFlag = 1;
      // }

        //
        // Delay 1 second before continuing
        //
        DEVICE_DELAY_US(250000);

        //
        // Increment the value in the transmitted message data.
        //
        txMsgData[0] += 0x01;
        txMsgData[1] += 0x01;
        txMsgData[2] += 0x01;
        txMsgData[3] += 0x01;
        txMsgData[4] += 0x01;
        txMsgData[5] += 0x01;
        txMsgData[6] += 0x01;
        txMsgData[7] += 0x01;

        //
        // Reset data if exceeds a byte
        //
        if(txMsgData[0] > 0xFF)
        {
            txMsgData[0] = 0;
        }
        if(txMsgData[1] > 0xFF)
        {
            txMsgData[1] = 0;
        }
        if(txMsgData[2] > 0xFF)
        {
            txMsgData[2] = 0;
        }
        if(txMsgData[3] > 0xFF)
        {
            txMsgData[3] = 0;
        }
        if(txMsgData[4] > 0xFF)
        {
         txMsgData[4] = 0;
         }
        if(txMsgData[5] > 0xFF)
               {
                   txMsgData[5] = 0;
               }
        if(txMsgData[6] > 0xFF)
               {
                   txMsgData[6] = 0;
               }
        if(txMsgData[7] > 0xFF)
               {
                   txMsgData[7] = 0;
               }
    }
}