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Serial port

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  • S Offline
    S Offline
    shirisha
    wrote on last edited by
    #21

    hi sir,

    int nreturn=0,len;
    char buf[5];
    QString str,s;

    QChar ch;

    while (TRUE)
    {

    nreturn = read(fd,&buf,1);

    str =buf[i];

    len = str.length();

    qDebug () << "no of bytes:" << len;

    for( i=0;i<len;i++)
    {

    ch = str.at(i);

    n+=ch.unicode();

    s = QString::number(n,16);

    }
    qDebug () << "Data:" << s;

    }

    Am able to display hex value, when data is only one byte and other problem is when continusly data is read only first byte is getting correct remaing am geting addition of the previous data . if i read 5 bytes of data am getting junk data .Please help me

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    • K Offline
      K Offline
      KushalAusula
      wrote on last edited by
      #22

      use this

      @QString a="a";
      QByteArray BA1=a.toUtf8();
      QByteArray BA2=BA1.toHex();
      const char* chArr1=BA2.constData();
      qDebug()<<QString::fromUtf8(chArr1);@

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      • McLionM Offline
        McLionM Offline
        McLion
        wrote on last edited by
        #23

        Is your fd the serialport?
        Again, as asked before, why are you not using QSerialPort?
        What is your target, the task you need to get done?

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        • K Offline
          K Offline
          KushalAusula
          wrote on last edited by
          #24

          Basic serial port usage as I have worked on is

          @ serial=new QSerialPort(this);

          serial->setPortName("/dev/ttyS0");
          serial->setBaudRate(9600);
          serial->setDataBits(QSerialPort::Data8);
          serial->setParity(QSerialPort::NoParity);
          serial->setFlowControl(QSerialPort::NoFlowControl);
          
          
          serial->open(QIODevice::ReadWrite);
          
          serial->write("Hello World");
          
          connect(serial,SIGNAL(readyRead()),this,SLOT(readSerialData()));@
          
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          • McLionM Offline
            McLionM Offline
            McLion
            wrote on last edited by
            #25

            .. and the readSerialData() ... (pseudo code)
            @
            void QTGUI_MainWindow::readSerialData()
            {
            while((iBytesAvailable = serial->bytesAvailable()))
            {
            QByteArray RawPortData = serial->read(iBytesAvailable);
            ...

            @

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            • S Offline
              S Offline
              shirisha
              wrote on last edited by
              #26

              int main(int argc, char *argv[])
              {

              QCoreApplication a(argc, argv);
              fd = open(MODEMDEVICE,O_RDWR|O_NOCTTY);

              While(true)

              {
              Buffer.clear();
              nreturn = read(fd,&chBuf,1);
              if(nreturn > 0)
              {
              for(i=0;i<nreturn;i++)
              {
              Buffer.append(chBuf[i]);

              if(chBuf[0] == 0xc9) nReadIndex = 0;

              pData[nReadIndex++] = chBuf[i];

              qDebug() << "data" << Buffer.toHex();
              }
              if(chBuf[0] == 0xcf)
              {

              if(nReadIndex >= 10)

              //Display of Gui opreration //

              nReadIndex = 0;

              }

              For this how can i use timers instead of while loop, where should i start timer , i tried but am geting segmentation problem.Please help me

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              • McLionM Offline
                McLionM Offline
                McLion
                wrote on last edited by
                #27

                Your issue seems not to be about the serial port. Please open a new thread for a new topic.

                btw: You seem to be very reluctant in using QSerialPort.

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                • S Offline
                  S Offline
                  shirisha
                  wrote on last edited by
                  #28

                  k .

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                  • S Offline
                    S Offline
                    shirisha
                    wrote on last edited by
                    #29

                    Hi sir,

                    How to flush the data in serial port without using qextserialport

                    Please help me sir...

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                    • S Offline
                      S Offline
                      shirisha
                      wrote on last edited by
                      #30

                      hi sir...,
                      When i use Baud rate B115200...am getting segmentation fault ..in qt...How would i solve the problem..Please help me...

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                      • S Offline
                        S Offline
                        shirisha
                        wrote on last edited by
                        #31

                        hi sir...,
                        When i use Baud rate B115200...am getting segmentation fault ..in qt...How would i solve the problem..Please help me...

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                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #32

                          Without any proper code, I can't.

                          Interested in AI ? www.idiap.ch
                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                          0
                          • SGaistS Offline
                            SGaistS Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on last edited by
                            #33

                            Without any proper code, I can't.

                            Interested in AI ? www.idiap.ch
                            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                            0
                            • S Offline
                              S Offline
                              shirisha
                              wrote on last edited by
                              #34

                              #define BAUDRATE B9600

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                              • S Offline
                                S Offline
                                shirisha
                                wrote on last edited by
                                #35

                                #define BAUDRATE B9600

                                1 Reply Last reply
                                0
                                • SGaistS Offline
                                  SGaistS Offline
                                  SGaist
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #36

                                  That won't really help debugging but from the looks of it, you are using the linux platform API, so please ask this on a linux dedicated forum.

                                  There's also this "how to":http://www.tldp.org/HOWTO/Serial-Programming-HOWTO/x115.html that should give you some hints and this "stack overflow post":http://stackoverflow.com/questions/6947413/how-to-open-read-and-write-from-serial-port-in-c

                                  Interested in AI ? www.idiap.ch
                                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                  1 Reply Last reply
                                  0
                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #37

                                    That won't really help debugging but from the looks of it, you are using the linux platform API, so please ask this on a linux dedicated forum.

                                    There's also this "how to":http://www.tldp.org/HOWTO/Serial-Programming-HOWTO/x115.html that should give you some hints and this "stack overflow post":http://stackoverflow.com/questions/6947413/how-to-open-read-and-write-from-serial-port-in-c

                                    Interested in AI ? www.idiap.ch
                                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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