Solved dataarray in QT sent to QSerialPort

[ktele]

Hello.

I have a code in MATLAB

fwrite(scom, hex2dec(['AA';'AA';'AA';'20';'01';'00';'00';'8F';'83']));

This is piece of data to be send to serial port device. How can I implement this code in QT as well.

Thanks in advance.

[jsulm]

Hi!
Did you read the documentation for QSerialPort? http://doc.qt.io/qt-5/qserialport.html
http://doc.qt.io/qt-5/qserialport.html#writeData
Example: http://doc.qt.io/qt-5/qtserialport-terminal-example.html

[ktele]

Thanks. However, I am very new to Qt. Can't deal with

QByteArray

properly. Can you write, how can send this data properly. I tried

write and writeData

however, couldn't get response. The port is opened and configured fine.

[jsulm]

What's the problem with QByteArray?
You should first learn the basics.
Did you verify that your request actually arrived?
In the example I posted you can find code to read from the serial port:

connect(serial, SIGNAL(readyRead()), this, SLOT(readData()));
...
void MainWindow::readData()
{
    QByteArray data = serial->readAll();
    console->putData(data);
}

[ktele]

Here is my code to send data to port, I can't send, the LED is not blinking on the sensor.

#include <QCoreApplication>
#include <QSerialPort>
#include <QSerialPortInfo>
#include <QDebug>
#include <QByteArray>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    foreach(const QSerialPortInfo &serialPortInfo, QSerialPortInfo::availablePorts()){
        qDebug() << serialPortInfo.portName() << "=" << serialPortInfo.description();
    }

    QSerialPort serial;
    serial.setPortName("COM3");
    serial.setBaudRate(QSerialPort::Baud115200);
    serial.setDataBits(QSerialPort::Data8);
    serial.setParity(QSerialPort::NoParity);
    serial.setStopBits(QSerialPort::OneStop);

    serial.open(QSerialPort::ReadWrite);

    if (serial.isOpen() && serial.isWritable())
    {
        qDebug() << "Serial is open and writable";
    }

    QByteArray bytes;
    bytes.resize(9);
    bytes[0] = 0xaa;
    bytes[1] = 0xaa;
    bytes[2] = 0xaa;
    bytes[3] = 0x20;
    bytes[4] = 0x01;
    bytes[5] = 0x00;
    bytes[6] = 0x00;
    bytes[7] = 0x8f;
    bytes[8] = 0x83;

    serial.write(bytes);

    serial.close();

    return a.exec();
}

Here I attach my MATLAB code, which is working

%Initialiazing COM port
scom=serial('COM3','BaudRate',115200,'Parity','none','DataBits',8,'StopBits',1);
fopen(scom);

for j=1:100
        %Start acquisition by sending command to port
        fwrite(scom,hex2dec(['AA';'AA';'AA';'20';'01';'00';'00';'8F';'83']));
        myData = fread(scom,79); %read RAW data
        showData=ones(32,1);
        for i=1:32
            showData(i,1)=myData(13+i*2)*16*16+myData(12+i*2); %Convert
        end
        showWin=(reshape(showData',4,8))';
        showWinStr=num2str(showWin); 
        [Xq,Yq]=meshgrid((1:0.5:4),(1:0.5:8));
        Vq = interp2(showWin,Xq,Yq);
        imagesc(Vq) %Plot as a image
        pause(0.1) 
end
%Stop acquisition by sending stop command to port
fwrite(scom,hex2dec(['AA';'AA';'AA';'22';'00';'00';'0E';'76']));
fclose(scom);

[kuzulis]

serial.write(bytes);
serial.waitForBytesWritten(-1); // << add this 
serial.close();

[ktele]

Thanks! It worked!