CreateFile打开串口很慢,该怎么处理

    BOOL OpenPort(int BaudRate,int DataBits,int StopBits,int Parity,HAND *temphand)
    {
        COMMTIMEOUTS CommTimeOuts;
        //打开串口
        (*temphand).hComm=CreateFile((*temphand).Port,GENERIC_READ|GENERIC_WRITE,0,0,OPEN_EXISTING,0,0);
        if((*temphand).hComm==INVALID_HANDLE_VALUE)
        {
            //AfxMessageBox(_T("无法打开端口或端口已经打开!请检查USB是否连接!    "));
            return FALSE;
        }
        GetCommState((*temphand).hComm,&dcb);
        dcb.BaudRate=BaudRate;
        dcb.ByteSize=DataBits;
        dcb.Parity=Parity;
        dcb.StopBits=StopBits;
        dcb.fParity=FALSE;
        dcb.fBinary=TRUE;
        dcb.fDtrControl=0;
        dcb.fRtsControl=0;
        dcb.fOutX=0;
        dcb.fInX=0;
        dcb.fTXContinueOnXoff=0;
        dcb.fAbortOnError = true;
        
        //设置状态参数
        SetCommMask((*temphand).hComm,EV_RXCHAR);        //串口事件：接收到一个字符
        SetupComm((*temphand).hComm,1024,1024);            //设置接收与发送的缓冲区大小
        if(!SetCommState((*temphand).hComm,&dcb))        //设置串口的DCB
        {
            AfxMessageBox(_T("无法按当前参数配置端口，请检查参数！"));
            ClosePort(temphand);
            return FALSE;
        }
        
        //设置超时参数
        GetCommTimeouts((*temphand).hComm,&CommTimeOuts);
        CommTimeOuts.ReadIntervalTimeout=1;            //接收字符间最大时间间隔；原值100
        CommTimeOuts.ReadTotalTimeoutMultiplier=1;
        CommTimeOuts.ReadTotalTimeoutConstant=1;    //读数据总超时常量；原值100
        CommTimeOuts.WriteTotalTimeoutMultiplier=0;
        CommTimeOuts.WriteTotalTimeoutConstant=0;
        if(!SetCommTimeouts((*temphand).hComm,&CommTimeOuts))
        {
            AfxMessageBox(_T("无法设置超时参数！"));
            ClosePort(temphand);
            return FALSE;
            
        }
        //AfxMessageBox(_T("打开成功"));
        //    PurgeComm((*temphand).hComm,PURGE_TXCLEAR|PURGE_RXCLEAR);        //清除收/发缓冲区
        
        return TRUE;
    }