serial programming

[pooch]

I am trying to write to serial port and read as well. Below is my code for it.
//mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <qextserialport.h>
#include <QDebug>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_pushButton_clicked()
{
        PortSettings portSettings;
        portSettings.BaudRate = BAUD9600;
        portSettings.DataBits = DATA_8;
        portSettings.Parity = PAR_EVEN;
        portSettings.StopBits = STOP_1;
        portSettings.FlowControl = FLOW_OFF;
        //portSettings.Timeout_Millisec=1000;
 
        port= new QextSerialPort("COM3",portSettings,QextSerialPort::EventDriven);
        QObject::connect(port,SIGNAL(readyRead()),this,SLOT(readData()));
        if(port->isOpen())
        {
            port->flush();
            port->close();
        }
        port->open(QextSerialPort::ReadWrite);
        if (port->isOpen())  {
            qDebug("connected!!");
            //delay->setInterval(2000);
 
        }
        else  qDebug("not connected");
        writeData(":0B1000408000102FA00DC\r\n");//this is the data that i need to send
}
void MainWindow::readData()
{
    port->flush();
    QByteArray response=port->readAll();
    ui->textBrowser->append(response);
}
void MainWindow::writeData(char* msg)
{
    port->write(msg);
    ui->textBrowser->append("writing data");
    ui->textBrowser->append(msg);
    port->flush();
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <qextserialport.h>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{
        PortSettings portSettings;
        portSettings.BaudRate = BAUD9600;
        portSettings.DataBits = DATA_8;
        portSettings.Parity = PAR_EVEN;
        portSettings.StopBits = STOP_1;
        portSettings.FlowControl = FLOW_OFF;
        //portSettings.Timeout_Millisec=1000;

        port= new QextSerialPort("COM3",portSettings,QextSerialPort::EventDriven);
        QObject::connect(port,SIGNAL(readyRead()),this,SLOT(readData()));
        if(port->isOpen())
        {
            port->flush();
            port->close();
        }
        port->open(QextSerialPort::ReadWrite);
        if (port->isOpen())  {
            qDebug("connected!!");
            //delay->setInterval(2000);

        }
        else  qDebug("not connected");
        writeData(":0B1000408000102FA00DC\r\n");//this is the data that i need to send
}
void MainWindow::readData()
{
    port->flush();
    QByteArray response=port->readAll();
    ui->textBrowser->append(response);
}
void MainWindow::writeData(char* msg)
{
    port->write(msg);
    ui->textBrowser->append("writing data");
    ui->textBrowser->append(msg);
    port->flush();
}

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this code writes to virtual serial(realterm) and even reads the response. But when i use hardware to write serial data to an atmega, no response is obtained. But i received response when i sent this data to atmega using python. Is there any fault in here?

[kuzulis]

You ca use QtSerialPort instead of QextSerialPort, because the QtSerialPort now is an part of Qt:

http://qt-project.org/wiki/QtSerialPort
http://qt-project.org/doc/qt-5.1/qts...ort-index.html

[anda_skoa]

You ca use QtSerialPort instead of QextSerialPort, because the QtSerialPort now is an part of Qt:

http://qt-project.org/wiki/QtSerialPort
http://qt-project.org/doc/qt-5.1/qts...ort-index.html

Isn't that only in Qt5?

According to the profile, pooch is using Qt4

Cheers,
_

[kuzulis]

Isn't that only in Qt5?

No, not only. QtSerialPort support Qt4 and/or Qt5. In case of Qt4 - user need to build it manually. Please read WIKI (the url above).

[pooch]

I installed qt5 from its site. But when i built the project, it gave me error like this:
:-1: error: Qt Creator needs a compiler set up to build. Configure a compiler in the kit options.
What do i have to do?

[pooch]

I installed qt5 from its site. But when i built the project, it gave me error like this:
:-1: error: Qt Creator needs a compiler set up to build. Configure a compiler in the kit options.
What do i have to do?

I solves this problem myself.

But according to QtSerialPort documentation, Configuring timeouts and delays while reading is not supported. What does that mean?
I actually need it to implement modbusmaster protocol and to timeout when no data is recived within 1 second as soon as i complete my write to serial port.
Also when i use qextserialport with qt5, when i try to open port, the application output says:
Starting E:\qt stuffs try only\qt5\build-untitled-Desktop_Qt_5_2_0_MinGW_32bit-Debug\debug\untitled.exe...
The program has unexpectedly finished.
E:\qt stuffs try only\qt5\build-untitled-Desktop_Qt_5_2_0_MinGW_32bit-Debug\debug\untitled.exe crashed.
what does this mean?
What do i do with it

[kuzulis]

But according to QtSerialPort documentation, Configuring timeouts and delays while reading is not supported. What does that mean?

This means that I/O is non-blocking and all of read/write operations returns immediately, without waiting.
It is necessary in order that not to lock of Qt event-loop, because it lead to freeze.

I actually need it to implement modbusmaster protocol and to timeout when no data is recived within 1 second as soon as i complete my write to serial port.

No problem:

...
...
QTimer *timer = new QTimer(this);
QSerialPort *port = new QSerialPort(this);
...
timer->setSingleShot(true);
...
connect(timer, SIGNAL(timeout()), this, SLOT(handleTimeout()));
connect(port, SIGNAL(readyRead()), this, SLOT(handleReadyRead()));
...
...
Foo::handleTimeout()
{
    // process of response timeout from the slave device
}
...
Foo::handleReadyRead()
{
    if (port->bytesAvailable() < expectedPacketLength)
        return;
 
    timer->stop();
    QByteArray receivedPacket = port->readAll();
 
    // do parse response from the slave device   
}
 
Foo::write()
{
    port->write(packetToSend);
    timer->start(1000); // run timer for the 1 sec timeout
}

...
...
QTimer *timer = new QTimer(this);
QSerialPort *port = new QSerialPort(this);
...
timer->setSingleShot(true);
...
connect(timer, SIGNAL(timeout()), this, SLOT(handleTimeout()));
connect(port, SIGNAL(readyRead()), this, SLOT(handleReadyRead()));
...
...
Foo::handleTimeout()
{
    // process of response timeout from the slave device
}
...
Foo::handleReadyRead()
{
    if (port->bytesAvailable() < expectedPacketLength)
        return;

    timer->stop();
    QByteArray receivedPacket = port->readAll();
     
    // do parse response from the slave device   
}

Foo::write()
{
    port->write(packetToSend);
    timer->start(1000); // run timer for the 1 sec timeout
}

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