Serial port Communication with pc through serial Adapter

[KroMignon]

@sankarapandiyan said in Serial port Communication with pc through serial Adapter:

serial->write(Data);

If you use QSerialPort::write(const char *data), write will stop on first 0 byte according to documentation => https://doc.qt.io/qt-5/qiodevice.html#write-1

You don't need to convert to plaint text, for binary data it is easier to use QByteArray

QTextStream stream(&inputFile);
    line = stream.readLine();
    while (!line.isNull()) {
            QByteArray outBytes = line.toUtf8();
            serial->write(outBytes);
            line = stream.readLine();
    }

[sankarapandiyan]

@artwaw said in Serial port Communication with pc through serial Adapter:

What I understand is, that you send line1 and wait for ack?

Yes you are cent percent right ... Is there is any possibility to get a ack from the PC by the code...

[sankarapandiyan]

@KroMignon said in Serial port Communication with pc through serial Adapter:

QTextStream stream(&inputFile);
line = stream.readLine();
while (!line.isNull()) {
QByteArray outBytes = line.toUtf8();
serial->write(outBytes);
line = stream.readLine();
}

Yes Even i have tried liked this , Even the output is like

Still the output is in single line i want it as line by line but i cant , give me some idea to do this task ..

[jsulm]

@sankarapandiyan said in Serial port Communication with pc through serial Adapter:

i want it as line by line

Then put it line by line into your text edit. What is the problem with this?
You can simply put a new line after each line:

ui->textEdit->setText(ui->textEdit->text() + '\n' + line);

[sankarapandiyan]

@jsulm

QTextStream stream(&inputFile);
   line = stream.readLine();
   while (!line.isNull()) {
           QByteArray inBytes;
           inBytes = line.toUtf8();
           serial->write(inBytes+ "\r" "\n"); // here i have added the "\r" and "\n" for split the word one by one 
           line = stream.readLine();
   }

I have a output like this ...

now its fine ...
But , if i press the send button its sends all the lines at the time. i need aknlment before sending the next word , so its want to repeat

Example , if i press the send button

line1 is in the recevier (another pc) ------- sended line1 in the aknowldgement (in my pc )
after getting aknwldgmnt ,
the line 2 wants to send (another pc) ---------- sended line2 in the aknowldgmnt (in my pc )

like wis it repeats for the four lines in the text file ..

Here how to get a aknowldgement in my code this is my code .. Give me some suggestions ..

void MainWindow::on_send_clicked()
{
     line   = ui->sender->toPlainText();
    QString txt1 = ui->receive->toPlainText();
    /*QString*/ txt3 = ui->aknowmnt->toPlainText();
    QFile inputFile(QString("/home/adx-soft1/Shankar/serial/myfile1.txt"));
    inputFile.open(QIODevice::ReadOnly);
    if (!inputFile.isOpen())
        return;

    QTextStream stream(&inputFile);
    line = stream.readLine();
    while (!line.isNull()) {
            QByteArray inBytes;
            inBytes = line.toUtf8();
            serial->write(inBytes+ "\r" "\n");
            line = stream.readLine();
    }
    ui->aknowmnt->setText("Sent Message -->" "\n"+  line + "\n");
}

void MainWindow::serialReceived()
{
    QString glen = serial->readAll();
    if (glen.length()>0){
    /*QString*/ line = ui->receive->toPlainText();
    ui->receive->setText(ui->receive->toPlainText()+line+"\n");
    ui->receive->setText(line + "\r\n" + glen + "\r\n");
    line = txt3;
    }
}

[jsulm]

@sankarapandiyan Well, currently you send everything at once in one loop. Do you have a protocol? I mean, the other side has to send an ack. Then it would work like this: you connect a signal to readyRead(), send first line, in slot connected to readyRead you read the ack and send next line and so on until you sent everything.

[J.Hilk]

@sankarapandiyan
here,
a very crude implementation on how one could do it

void MainWindow::checkAndSendData()
{
    if(!m_lines.isEmpty()){
        QByteArray baToSend = m_lines.takeFirst().toUtf8();
        serial->write(baToSend);
        ui->aknowmnt->setText("Sent Message -->" "\n"+  QString(baToSend) + "\n");
    } else {
        ui->aknowmnt->setText("All send");
    }
}

void MainWindow ::on_send_clicked()
{
    line   = ui->sender->toPlainText();
        QString txt1 = ui->receive->toPlainText();
        /*QString*/ txt3 = ui->aknowmnt->toPlainText();
        
        //m_lines is a member QStringList
        if(m_lines.isEmpty()){
            QFile inputFile(QString("/home/adx-soft1/Shankar/serial/myfile1.txt"));
            inputFile.open(QIODevice::ReadOnly);
            if (!inputFile.isOpen())
                return;
        
            QTextStream stream(&inputFile);
            while(!stream.atEnd()){
                QString line = stream.readLine();
                m_lines.append(line + QString("\r\n"));
            }
        }
        
        checkAndSendData();
}

void MainWindow::serialReceived()
{
    QString glen = serial->readAll();
    if (glen.length()>0){
    /*QString*/ line = ui->receive->toPlainText();
    ui->receive->setText(ui->receive->toPlainText()+line+"\n");
    ui->receive->setText(line + "\r\n" + glen + "\r\n");
    line = txt3;
    }
    
    checkAndSendData();
}

[sankarapandiyan]

@J-Hilk

Hi i have used the code , finally i got the acknowldgement

But i want to send it automatically , Here i am pressing send button for every data , like if i click the send button first time , it sends the line 1 only , i want to send the line 1 and line 2 and line 3 and line 4 with single click but at the time the the ack also i want to get automatically .

Is it possible to get like this ..

this is my Edited Code ..

void MainWindow::checkAndSendData()
{
    if(!m_lines.isEmpty()){
        QByteArray inBytes;
        QByteArray baToSend = m_lines.takeFirst().toUtf8();
        serial->write(baToSend);
        ui->aknowmnt->setText("Sent Message -->" "\n"+ QString(baToSend) + "\n");
    } else {
        ui->aknowmnt->setText("All send");
    }
}

void MainWindow::on_send_clicked()
{
     line   = ui->sender->toPlainText();
    QString txt1 = ui->receive->toPlainText();
    /*QString*/ txt3 = ui->aknowmnt->toPlainText();

     if(m_lines.isEmpty()){
    QFile inputFile(QString("/home/adx-soft1/Shankar/serial/myfile1.txt"));
    inputFile.open(QIODevice::ReadOnly);
    if (!inputFile.isOpen())
        return;

    QTextStream stream(&inputFile);
    while (!stream.atEnd()){
            line = stream.readLine();
            m_lines.append(line+QString("\r\n"));
    }
     }
     checkAndSendData();
}

void MainWindow::serialReceived()
{
    QString glen = serial->readAll();
    if (glen.length()>0){
    /*QString*/ line = ui->receive->toPlainText();
    ui->receive->setText(ui->receive->toPlainText()+line+"\n");
    ui->receive->setText(line + "\r\n" + glen + "\r\n");
    line = txt3;
    }
   checkAndSendData();
}

Give_Me_Some_Solution_for_this_Sir.

[J.Hilk]

@sankarapandiyan
🤔

It should do that automatically.
See the checkAndSendData();at the end of your serialReceived function. That will call the same function to write the next line.

same as button pressed again.

are you sure serialReceived is actually called?

[sankarapandiyan]

@J-Hilk yes i called the function , But i didnot get it automatically

void MainWindow::serialReceived()
{
    QString glen = serial->readAll();
    if (glen.length()>0){
    /*QString*/ line = ui->receive->toPlainText();
    ui->receive->setText(ui->receive->toPlainText()+line+"\n");
    ui->receive->setText(line + "\r\n" + glen + "\r\n");
    line = txt3;
    }
   checkAndSendData();
}

[jsulm]

@sankarapandiyan Is your serialReceived() called?

[sankarapandiyan]

@jsulm said in Serial port Communication with pc through serial Adapter:

Is your serialReceived() called?

serial received called in where ? i didnt understand , actually i acalled checkAndSendData(); in Serial received ..

But i dont know where to call serialReceived() Function in my code

[jsulm]

@sankarapandiyan serialReceived() is a slot and needs to be connected to readRead signal - did you connect it? Else it will not be called when you get ack.

[sankarapandiyan]

@jsulm @J-Hilk I Have tried like this

void MainWindow::on_send_clicked()
{
     line   = ui->sender->toPlainText();
    QString txt1 = ui->receive->toPlainText();
    /*QString*/ txt3 = ui->aknowmnt->toPlainText();

     if(m_lines.isEmpty()){
    QFile inputFile(QString("/home/adx-soft1/Shankar/serial/myfile1.txt"));
    inputFile.open(QIODevice::ReadOnly);
    if (!inputFile.isOpen())
        return;

    QTextStream stream(&inputFile);
    while (!stream.atEnd()){
            line = stream.readLine();
            m_lines.append(line+QString("\r\n"));
    }

     }
     checkAndSendData();
     serialReceived(); // Here I have call a function but it also make no sense i think.
}

[jsulm]

@sankarapandiyan This does not answer my question.
Did you connect serialReceived() to readyRead()? Can you please answer this question?

[J.Hilk]

@sankarapandiyan
you're right, it makes no sense there.

serialReceived should be a slot (and it has to be markt as such inside your header file) that is called when the serial port emits the readyRead signal.

Ideale, you should never call this slot manually, from within your own source code.

change your connect to the new syntax
from

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

to

connect(serial, &QSerialPort::readyRead,this, &MainWindow::serialReceived);

It should/could solve a couple of issues

[sankarapandiyan]

@jsulm said in Serial port Communication with pc through serial Adapter:

This does not answer my question.
Did you connect serialReceived() to readyRead()? Can you please answer this question?
Yes Connected..

void MainWindow::on_pushButton_clicked()
{
    serial = new QSerialPort (this) ;
    serial->setPortName(ui->comboBox->currentText());
    serial->setBaudRate (QSerialPort::Baud115200);
    serial->setDataBits(QSerialPort::Data8);
    serial->setParity (QSerialPort::NoParity);
    serial->setStopBits (QSerialPort::OneStop);
    serial->setFlowControl(QSerialPort::NoFlowControl);
    serial->open(QIODevice::ReadWrite);
    connect(serial,SIGNAL(readyRead()),this, SLOT (serialReceived())); //**HERE_I_CONNECTED_THE_SERIALRECEIVED_SLOT**
    ui->progressBar->setValue(100);
//    ui->receive->clear();
}

[jsulm]

@sankarapandiyan OK, I didn't noticed, sorry.
Check @J-Hilk response and make sure your slot is called (put a qDebug() there).

[sankarapandiyan]

@J-Hilk said in Serial port Communication with pc through serial Adapter:

connect(serial, &QSerialPort::readyRead,this, &MainWindow::serialReceived);

Thanks a lot . I have changed the code
from

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

to

connect(serial, &QSerialPort::readyRead,this, &MainWindow::serialReceived);
but same output is came

[KroMignon]

@sankarapandiyan said in Serial port Communication with pc through serial Adapter:

connect(serial,SIGNAL(readyRead()),this, SLOT (serialReceived())); //HERE_I_CONNECTED_THE_SERIALRECEIVED_SLOT

You should prefer using new connect style, so connect validity will be checked at compilation:

connect(serial, &QSerialPort::readyRead,this, &MainWindow::serialReceived);

And then in the slot:

void MainWindow::serialReceived()
{
    QByteArray rawData;
    while(!serial->atEnd())
    {
        rawData.append(serial->readAll());
    }
    if(!rawData.isEmpty())
    {
        QString glen = QString(rawDaa);
       /*QString*/ line = ui->receive->toPlainText();
       ui->receive->setText(ui->receive->toPlainText()+line+"\n");
       ui->receive->setText(line + "\r\n" + glen + "\r\n");
       line = txt3;
    }
    checkAndSendData();
}

Or if you are sure always receiving a '\r' or '\n' from your device, you can do it like this:

void MainWindow::serialReceived()
{
    while(serial->canReadLine())
    {
        QString glen = QString(serial->readLine());
       /*QString*/ line = ui->receive->toPlainText();
       ui->receive->setText(ui->receive->toPlainText()+line+"\n");
       ui->receive->setText(line + "\r\n" + glen + "\r\n");
       line = txt3;
    }
    checkAndSendData();
}

look at documentation ==> https://doc.qt.io/qt-5/qserialport.html#canReadLine