Receiving garbage data from serial port

[samsam]

I'm using serial port class for transferring data from machine to machine. Before I open the port I define the following settings:

@Port = new QSerialPort(this);
Port ->setPortName("COM16");
Port ->setBaudRate(QSerialPort::Baud115200);
Port ->setDataBits(QSerialPort::Data8);
Port ->setParity(QSerialPort::NoParity);
Port ->setFlowControl(QSerialPort::NoFlowControl);
Port ->setStopBits(QSerialPort::OneStop);
Port ->clear();@
My problem is, that sometimes when I run my app I get from the Serial port garbage data, the issue gets fixed when I open ExtraPutty tool (http://www.extraputty.com/download.php) on the same port- I get their the correct data and afterwards when I open my application everything is OK and I receive normal data. Probably the ExtraPutty defines some setting that I missed and the settings stays when I open the port from my application. can some one help me figure out what is the issue?

[SGaist]

Hi,

You didn't open the serial port before doing the rest

[samsam]

well, I didn't write here the line that I'm opening the port, I open the port after setting these above details.
for the case it makes sense I'm adding here the code that opens the port:

@Port->open(QIODevice:: ReadWrite);
if ((Port->isOpen()))
{
Port->clear();

    connect(Port, SIGNAL(readyRead()), this,SLOT(DataReceived()));
   
}
else
{
    QMessageBox::critical(this, tr("Error"), Port->errorString());
}@

[SGaist]

You have to open it before setting anything

[kuzulis]

Also, you should to check the return from the all setXX() methods.

[samsam]

I checked the return. the return is false and the last error message is: "the handle is invalid"

what does it mean, and what should I do in order to fix it?

[kuzulis]

bq. what does it mean,

It means that the device isn't opened.

bq. and what should I do in order to fix it?

For the old Qt versions (is lower than 5.3.1) it is necessary: at first - try to open device, and second - try to do setXX() methods (but not vice versa!!!).

Now (for the Qt 5.3.1 and above) in it there is no need: it is possible to do setXX() before device opening.

But anyway it is necessary always to do check of return codes.