Cant read strings with Raspberry via QtSerial

bladekel

Hello to all,
I'am trying to read string coming from arduino to my raspberry. On raspberry pi2, I'm using qt4 with jessie and connecting raspberry with arduino via usb.

I send data from arduino like;

void setup(){
  Serial.begin(9600);
}

void loop(){
Serial.println("123456789");
delay(2000);
}

On the raspberry I'm trying to read like;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    serial = new QSerialPort(this);
    serial->setPortName("ttyACM0");
    serial->setBaudRate(QSerialPort::Baud9600);
    serial->setDataBits(QSerialPort::UnknownDataBits);
    serial->setParity(QSerialPort::NoParity);
    serial->setStopBits(QSerialPort::OneStop);
    serial->setFlowControl(QSerialPort::NoFlowControl);
    serial->open(QIODevice::ReadWrite);
    connect(serial,SIGNAL(readyRead()),this,SLOT(data_received()));

}

void MainWindow::data_received()
{
    QByteArray incomingData;
    incomingData=serial->readAll();
    qDebug(incomingData);
}

With qt terminal example, I read the data perfect.
But with my code above;

What must I do? Any suggests?

SGaist

Hi,

qDebug by default will add a new line at destruction hence what you see.

If you want to modify that behaviour, take a look at this.

bladekel

@SGaist
Thanks for your reply.
But when I tried to change the text of a label, or check the received data, I couldnt success.
When I update the text of a label, I got 6789, 23456789, 123456 etc.
And after those tries I saw that with qdebug I couldnt read the data clearly.

And as I sad before , I can read the data clearly with QtSerial terminal example.

What I'm trying to do is, checking the received data and updating the gpio pins...

SGaist

The terminal example does only one thing: it appends whatever is received to the Console widget.

The usual way to ensure good communication on a serial port is to have a protocol in place that helps you know when you have received a "full frame" of data.

Then on the receiving part, you accumulate the data in a buffer until you have enough to recreate that frame and then process it.

bladekel

@SGaist
Can you suggest me an example ?

kuzulis

serial->setDataBits(QSerialPort::UnknownDataBits);

It is best solution! ))

SGaist

What kind of example are you looking for ?