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QSerialPort Screen 4D system



  • Hi everybody,

    I bought a screen from 4D system (uLCD-24PTU)

    I want use QSerialPort to comminucate with this screen but I have some trouble with byte read.

    Normaly I would read for some action [07 1E 00 00 00 19]

    but when I read in slot :

    void MainWindow::readData()
    {
        qDebug() << "---------------------------";
    
        QByteArray data = screen->readAll();
        qDebug() << data << data.size();
    }
    

    Sometime I have the corret response in on time.

    "\x07\x1E\x00\x00\x00\x19" 6

    But sometime, in two time

    "\x07\x1E" 2

    "\x00\x00\x00\x19" 4

    How can have reply in one time ? ("\x07\x1E\x00\x00\x00\x19" 6)

    Thanks


  • Qt Champions 2019

    @Franckynos I don't think you can. Use http://doc.qt.io/qt-5/qiodevice.html#readyRead signal to read in a buffer until you got what you need. readAll() just returns what currently is there.


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