Trouble sending Data with QSerialPort

问题

I am trying to write a QT application that can communicate with a propeller over USB. Reading through the documentation QSerialPort seems to be exactly what I need. For a simple test, I am trying to send the number "2" to my propeller project. The project itself has its own OLED screen that I can read results on. Here is the QT code itself:

this->Serial=new QSerialPort(this);
this->Serial->setPortName("/dev/ttyUSB0");
this->Serial->setBaudRate(QSerialPort::Baud9600);
connect(this->Serial,SIGNAL(error(QSerialPort::SerialPortError)),this,SLOT(errorReport(QSerialPort::SerialPortError)));

if(this->Serial->open(QIODevice::ReadWrite))
{
    QByteArray dayArray;
    QDataStream stream(&dayArray, QIODevice::WriteOnly);
    stream << 2;
    qDebug()<< dayArray.toHex();
    qDebug()<< this->Serial->portName();
    if(this->Serial->setDataBits(QSerialPort::Data8))
    {
        qDebug()<<"bits set to 8";
    }
    this->Serial->write(dayArray.toHex());
    this->Serial->waitForBytesWritten(-1);
    this->Serial->close();
}

and the error report slot is:

void serial::errorReport(QSerialPort::SerialPortError error)
{
 if(error!=0)
     qDebug()<<"ERROR:"<<endl<<error;
}

The console debug statements print this:

"00000002" 
"ttyUSB0" 
bits set to 8 

However when I read the values the propeller recieves, it ranges from 0xD0, 0xF0, or 0xE0, not the 0x02 I was expecting. The baud rates in the code match that of the chip and I am really not sure what is wrong. Can anyone point out the fault?

EDIT: I know that the propeller code isn't the problem as it works fine with the Arduino's IDE serial console.

回答1:

I finally figured it out. The working code is as follows:

if(this->Serial->open(QIODevice::ReadWrite))
{
    this->Serial->setBaudRate(QSerialPort::Baud9600);
    this->Serial->setParity(QSerialPort::NoParity);
    this->Serial->setStopBits(QSerialPort::OneStop);
    this->Serial->setFlowControl(QSerialPort::NoFlowControl);
    this->Serial->setDataBits(QSerialPort::Data8);

    QByteArray dayArray;
    dayArray[0]=2;
    this->Serial->write(dayArray);
    this->Serial->waitForBytesWritten(-1);
    this->Serial->close();
}

来源：https://stackoverflow.com/questions/18806001/trouble-sending-data-with-qserialport