Using QSerialPort in multi widget application

[jsulm]

@viniltc You need to use an instance of tetraSerial class

[viniltc]

@mrjj

It is a GUI to communicate with an FTDI based serial device.

• There will be setup stages having three windows. At the end of setup, the GUI should send a 'config file' to the serial device (say CPU -A)

• During those setup stages, GUI should also read the serial device to get real-time updates of some sensors connected to the device (CPU-B). Also writing to some registers of the device.

• For example, I have three windows - window1, window2, window3. The 'config file' will be sent at window 3. The user will be seeing some sensor values in window2 and updating its parameters by writing into some short registers.

All the above operations will be done through a single FTDI based serial (UART).
So what I need is to get an instance of opened serial port' in any of those windows to read or write

Any thoughts?

[viniltc]

@jsulm

I try to modify the class file as follows:

#include "tetraserial.h"


tetraSerial::tetraSerial(QObject *parent) : QObject(parent)
{

}

void tetraSerial::serialOpen()
{
    
    serialObject = new QSerialPort();
    serialObject->setPortName("com5");
    serialObject->setBaudRate(1000000);
    serialObject->setDataBits(QSerialPort::Data8);
    serialObject->setParity(QSerialPort::NoParity);
    serialObject->setStopBits(QSerialPort::OneStop);
    serialObject->setFlowControl(QSerialPort::HardwareControl);
    serialObject->open(QIODevice::ReadWrite);
    
    
}

void tetraSerial::serialRecived2()
{
    
}

and the header as follows:

#ifndef TETRASERIAL_H
#define TETRASERIAL_H

#include <QObject>
#include <QtSerialPort/QSerialPort>
#include <QtSerialPort/QSerialPortInfo>
#include <QDebug>
#include <QFile>
#include <QMessageBox>

class tetraSerial : public QObject
{
    Q_OBJECT
public:
    explicit tetraSerial(QObject *parent = nullptr);

  //  static QSerialPort *serialObject;
  QSerialPort *serialObject;
  
  void serialOpen()
    

signals:

public slots:
          void serialRecived2();
};

Then I use this in the main as:

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow) 
{
    ui->setupUi(this);
 
  tetraSerial serial;
  serial.serialOpen();
  
  connect(serial, SIGNAL(readyRead()), this, SLOT(serialRecived2()));


}

I've got an error says:

no matching member function for call to 'connect'

I don't understand why the connect function can't find a matching function.

[jsulm]

@viniltc What is serial in

connect(serial, SIGNAL(readyRead()), this, SLOT(serialRecived2()));

?
It needs to be a pointer:

connect(&serial, SIGNAL(readyRead()), this, SLOT(serialRecived2()));

[viniltc]

@jsulm

I'm getting a runtime error saying
QObject::connect: No such signal tetraSerial::readyRead() in ..\serialPortTest\mainwindow.cpp:54 QObject::connect: (receiver name: 'MainWindow')

I already configured the serial port in the tetraSerial class as shown above. What might be the cause?

Also
I'm a bit confused about where to define signals and slots. As you can see I've opened the device in my tetraSerial class in a method called serialOpen. Now I want to communicate with for example two forms. When I press Read button in form1 , the data shluld be displayed on a textbox in form 1. In form 2, when I press Write, it shluld write a file into the opened device.

My confusion where should I define signals and slots and where should I connect them?

[aha_1980]

@viniltc

My confusion where should I define signals and slots and where should I connect them?

• signals: in the sender
• slots: in the receiver
• connect: in a class that knows both other classes or in the receiver (but not in the sender!)

[mrjj]

Hi

QObject::connect: No such signal tetraSerial::readyRead() in ..\serialPortTest\mainwindow.cpp:54 QObject::connect: (receiver name: 'MainWindow')

its the serialObject inside tetraSerial that has the signal so that must be used in the connect

connect(serial.serialObject, SIGNAL(readyRead()), this, SLOT(serialRecived2()));

Also, here the tetraSerial serial; is a local variable and will not survive
long enough to get any data as it will be deleted as soon as constructor ends.
it should be as a member of MainWindow

tetraSerial serial; <<< im local. 
serial.serialOpen();  
connect(seriall.serialObject, SIGNAL(readyRead()), this, SLOT(serialRecived2()));