can't set serial port data bits

[yyiu002]

Hi everyone,

I had bit problem on setting up serial port parameters.


port->setBaudRate(BAUD9600);
port->setFlowControl(FLOW_OFF);
port->setParity(PAR_NONE);
port->setDataBits(DATA_8);
port->setStopBits(STOP_1);
port->setRts(true);
port->setDtr(true);
port->setTimeout(500);

if (port->open(QIODevice::ReadWrite))
{
qDebug()<<"Port Info";
qDebug()<<"---------";
qDebug()<<port->baudRate();
qDebug()<<port->dataBits();
qDebug()<<port->portName();
qDebug()<<"---------";
}


What I get back from dataBits() funtion is 3, not 8, what's wrong?

[yyiu002]

DATA_8 might be 3, silly me.

But my problem is if port was set correctly, why can't it receive correct data?
After I use VB application initialized the serial port, send out data correctly, then went back to this QT application, I can send and receive correctly.

But if not using this VB application refresh the port, QT App won't run properly, has anyone met with problem before?

[kuzulis]

yyiu002,

Can you advise to use the library QSerialDevice. As an alternative QextSerialPort:

http://qt-apps.org/content/show.php/QSerialDevice?content=112039

But version 0.2.0 is already out of date. The latest version is on the SVN here: fireforge.net

But the site fireforge.net are no longer working :(.
I will try to create a repository QSerialDevice today at: http://gitorious.org/

[Lesiok]

DataBitsType retiurned by dataBits() is an enum. And 3 is DATA_8.
Are You sure that all parameters are correct, ie. parity, stop bits.

[msrihari]

are you using rts and dtr signals, if not set them false and make a try.

[yyiu002]

I also tried with qextserialport 's example project, event folder, it gives me the same thing, not working!


QextSerialPort * port = new QextSerialPort("COM8", QextSerialPort::EventDriven);
port->setBaudRate(BAUD9600);
port->setFlowControl(FLOW_OFF);
port->setParity(PAR_NONE);
port->setDataBits(DATA_8);
port->setStopBits(STOP_1);
port->open(QIODevice::ReadWrite);
if (!(port->lineStatus() & LS_DSR)) {
out << "warning: device is not turned on" << endl;
}

[yyiu002]

It works for me now, have to open the serial port first, then set parameters.



port = new QextSerialPort(comPort, QextSerialPort::EventDriven);
port->open(QIODevice::ReadWrite);

// qDebug()<<baudSel;

port->setBaudRate(baudSel);
port->setDataBits(DATA_8);
port->setParity(PAR_NONE);
port->setStopBits(STOP_1);
port->setFlowControl(FLOW_OFF);
port->setTimeout(500);
port->setRts(true);
port->setDtr(true);



QextSerialPort seems work fine.

will try QSerialPort later if having other problems and can't be resolved.

Many thanks on everyone on helping me on this.