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()<<"---------";
    }

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()<<"---------";
    }

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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/...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But version 0.2.0 is already out of date.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;
	}

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;
	}

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[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);

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);

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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.