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!