How to open more than once SerialPort

[erytcg]

Hello, I'm new on forum and QT :)
I create a application which connect via serial port with devices. I have a problem with connect more than one device via serialport.
I use code from example.

void MainWindow::openSerialPort()
{
    SettingsDialog::Settings p = settings->settings();
    serial->setPortName(p.name);
    serial->setBaudRate(QSerialPort::Baud9600);
    serial->setDataBits(QSerialPort::Data8);
    serial->setParity(QSerialPort::NoParity);
    serial->setStopBits(QSerialPort::OneStop);
    serial->setFlowControl(QSerialPort::NoFlowControl);

    if (serial->open(QIODevice::ReadWrite)) { 
        ui->connectAction->setEnabled(false);
        ui->disconnectAction->setEnabled(true);
        ui->settingsAction->setEnabled(false);
        showStatusMessage(tr("Connected to %1 : OK")
                          .arg(p.name));
    } else { 
        QMessageBox::critical(this, tr("Error"), serial->errorString());

        showStatusMessage(tr("Open error"));
    }
}

Someone have good idea how open more ports.
I would be grateful for help.

[SGaist]

Hi and welcome to devnet,

Only one solution: have as many QSerialPort objects.

Using e.g. a QVector<QSerialPort*> as member variable to keep them easily manageable.

[mostefa]

Hi @erytcg

To open more than one serialport

you have two create more than one instance of QSerialPort:

For example you have two serial ports on your device : (ttyUSB0, ttyUSB1)

To open these ports you have to do something like this:

QSerialPort* firstSerialPort = new QSerialPort();
QSerialPort* secondSerialPort = new QSerialPort();

firstSerialPort->setPortName("ttyUSB0");
secondSerialPort->setPortName("ttyUSB1");
.
.
.
if (firstSerialPort->open(QIODevice::ReadWrite))
.
.
.
if (secondSerialPort->open(QIODevice::ReadWrite))
.
.
.

I hope this can help you

[erytcg]

@mostefa I think it's not good idea i don't know how many devices I have to connect
@SGaist can yoiu show me example how add add object to QVector and obtain acces to serialport name

[mostefa]

@erytcg said in How to open more than once SerialPort:

@mostefa I think it's not good idea i don't know how many devices I have to connect

Then what about ?

QVector<QSerialPort *> v;
    Q_FOREACH(QSerialPortInfo port, QSerialPortInfo::availablePorts()) {
        QSerialPort* serialPort = new QSerialPort() ;

//Here set port informations
        serialPort->setPort(port);
.
.
.

         if (serialPort->open(QIODevice::ReadWrite))
{
.
.
              v.append(serialPort);
}
  }

[erytcg]

void MainWindow::openSerialPort()
{         
    QVector<QSerialPort *> v;
        Q_FOREACH(QSerialPortInfo port, QSerialPortInfo::availablePorts())
        {
           QSerialPort* serialPort = new QSerialPort();
           serialPort->setPort(port);
           serialPort->setBaudRate(QSerialPort::Baud9600);
           serialPort->setDataBits(QSerialPort::Data8);
           serialPort->setParity(QSerialPort::NoParity);
           serialPort->setStopBits(QSerialPort::OneStop);
           serialPort->setFlowControl(QSerialPort::NoFlowControl);

            if (serialPort->open(QIODevice::ReadWrite)) {
                 v.append(serialPort);
                 ui->listWidget->addItem(p.name);
              
            } else { 
                QMessageBox::critical(this, tr("Error"), serialPort->errorString());

                showStatusMessage(tr("Open error"));
            }
        }

}

void MainWindow::closeSerialPort()
{
    if (serialPort->isOpen())
    {
        serialPort->close();
        QList<QListWidgetItem*> items = ui->listWidget->selectedItems();
        foreach(QListWidgetItem * item, items)
        {
            delete ui->listWidget->takeItem(ui->listWidget->row(item));
        }
    }

    showStatusMessage(tr("Disconnected"));
}

it's ok?

[mrjj]

Hi
In void MainWindow::closeSerialPort()
you call if (serialPort->isOpen())

But that is only serialPort pointer. you are not using the
Vector<QSerialPort *> v; at all so i wonder if this is what u want ?

I imagine you need to loop over v and close all and not just whatever
serialPort points to ?

[erytcg]

I don't understand good with this QVector. I don't know how acces to one of port and close one port not all.

[mrjj]

@erytcg
Hi
its a list of comports.

so v[index] gives a QSerialPort *

But you will have to answer what app does.

Currently you open all comports available on device.

Should closeSerialPort() close them all again?

to close one you would do
QSerialPort * Cur=v[0];
Cur->close();
or even
v[0]->close();

Notice i use 0 for closing the first.

So to help you , i need to understand what app does as its uncommon to open ALL comports :)

[erytcg]

So I need more functions, one for add aviable ports to vector and one to open specific port? For close functions I want close only one port.

[mrjj]

@erytcg

• close functions I want close only one port.

But which one?

[erytcg]

Choosing from:
QList<QListWidgetItem*> items = ui->listWidget->selectedItems();
foreach(QListWidgetItem * item, items)
{
delete ui->listWidget->takeItem(ui->listWidget->row(item));
}

[mrjj]

Hi
if you move
QVector<QSerialPort *> v;
to the MainWindow.h (in the class)
and remove serialPort variable also!

then you could do

void MainWindow::closeSerialPort( int index)
{
QSerialPort * serialPort = v[index];
if (serialPort->isOpen())
{
serialPort->close();
..

and close the one u want with
closeSerialPort( some number)

[mrjj]

Oh u posted while i was writing

Can you use the row index directly to the V list ?

[erytcg]

yes I want to add opened COMports to ListWidget and close selected ports

[mrjj]

@erytcg

If there is a 1 to 1 to the V list ( please rename to comports or something :)

Then you can just use the
void MainWindow::closeSerialPort( int index)
{
QSerialPort * serialPort = v[index];
...

and call it from
foreach(QListWidgetItem * item, items) {
int index= ui->listWidget->row(item); //
closeSerialPort( index);

[erytcg]

Hey can you look at code? Now it's ok? :)

void MainWindow::addAvailableSerialPorts()
{
    QVector<QSerialPort *> v;
    Q_FOREACH(QSerialPortInfo port, QSerialPortInfo::availablePorts())
        {
           QSerialPort* serialPort = new QSerialPort();
           serialPort->setPort(port);
           serialPort->setBaudRate(QSerialPort::Baud9600);
           serialPort->setDataBits(QSerialPort::Data8);
           serialPort->setParity(QSerialPort::NoParity);
           serialPort->setStopBits(QSerialPort::OneStop);
           serialPort->setFlowControl(QSerialPort::NoFlowControl);
           v.append(serialPort);
        }
}
void MainWindow::openSerialPort(int index)
{         
    QSerialPort * serialPort = v[index];
    if (serialPort->open(QIODevice::ReadWrite)) 
     {
         showStatusMessage(tr("Connected to %1 : OK").arg(p.name));
     } 
    else 
    {
         QMessageBox::critical(this, tr("Error"), serialPort->errorString());
         showStatusMessage(tr("Open error"));
    }
}

[mrjj]

@erytcg said in How to open more than once SerialPort:

Almost but one fatal error !

void MainWindow::addAvailableSerialPorts()
{
QVector<QSerialPort *> v; <<<< This is a local var. It should be in class. windows .h. should not be defined here. only used.

So in
void MainWindow::openSerialPort(int index)
{
QSerialPort * serialPort = v[index]; <<< what v is this . it cannot be the one from addAvailableSerialPorts as that was local.

[erytcg]

ok I add *QVector<QSerialPort > v; to private: mainwindow.h
I have problem with close function port chooseing from list widget

[mrjj]

@erytcg

you need to use the row int as index

foreach(QListWidgetItem * item, items) {
int index= ui->listWidget->row(item); //
closeSerialPort( index);