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write on serial port in thread

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #7

    Then can you describe how the communication should work ?
    Can you share your current code ?

    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
    • HamedH Offline
      HamedH Offline
      Hamed
      wrote on last edited by Hamed
      #8

      yes I can. I know this is off topic but first I put my reading part of code that crashes after a while.
      this is reading and managing part :

      QByteArray header;
      quint8 ID;
      quint8 msg_len;
      quint8 first;
      quint8 second;
      quint8 seq;
      QByteArray payload;
      void ReaderThread::read()
      {//1
      while(serial->isOpen())
      {//2
      if(serial->bytesAvailable() >= 200)
      {//3
      QThread::msleep(1);
      header = serial->read(1);
      if(header.contains(254))
      {//4
      QThread::msleep(5);
      header.append(serial->read(5));
      msg_len = header[1];
      seq = header[2];

                 first = header[3];
                 second = header[4];
                 ID = header[5];
                 if(msg_len != NULL && first != NULL && second != NULL && ID != NULL && seq != NULL)
                 {//5
                     if(msg_len > 0 && msg_len < 100)
                     {//6
                         if((first == 01) && (second == 01))
                         {//7
                             if(seq >= 0 && seq <=254)
                             {
                                 packet_counter++;
                             }
                             if(seq == 255)
                             {
                                 packet_counter++;
                                 if(packet_counter <= 256)
                                 {
                                      rssi = (packet_counter*100)/256;
                                      emit mRssi(rssi);
                                 }
                                 packet_counter = 1;
                             }
                             QThread::msleep(12);
                             payload = serial->read(msg_len);
                             switch (ID)
                             {
                                 case (ATTITUDE) :
                                     {
                                         mavlink_attitude_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_attitude_t));
                                         emit attitude(data);
                                     }
      
                                     break;
                                 case (SCALED_PRESSURE) :
                                     {
                                         mavlink_scaled_pressure_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_scaled_pressure_t));
                                         emit scaled_pressure(data);
                                     }
                                     break;
                                 case (SENSOR_OFFSETS) :
                                     {
                                         mavlink_sensor_offsets_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_sensor_offsets_t));
                                         emit sensor_offsets(data);
                                     }
                                     break;
                                 case (SYS_STATUS) :
                                     {
                                         mavlink_sys_status_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_system_time_t));
                                         emit sys_status(data);
                                     }
                                     break;
      
                                 case (GPS_RAW_INT) :
                                     {
                                         mavlink_gps_raw_int_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_gps_raw_int_t));
                                         emit gps_raw_int(data);
                                     }
                                     break;
                                 case (SERVO_OUTPUT_RAW) :
                                     {
                                         mavlink_servo_output_raw_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_servo_output_raw_t));
                                         emit servo_output_raw(data);
                                     }
                                     break;
                                 case (RC_CHANNELS_RAW) :
                                     {
                                         mavlink_rc_channels_raw_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_rc_channels_raw_t));
                                         emit rc_channels_raw(data);
                                     }
                                     break;
                                 case (WIND) :
                                     {
                                         mavlink_wind_t data;
                                         memcpy(&data,payload.data(),sizeof(mavlink_wind_t));
                                         emit wind(data);
                                     }
                                     break;
                             }
                         }//7
                         else
                         {//8
                             header.clear();
                         }//8
                     }//6
                 }//5
      
             }//4
             else
             {//9
                 header.clear();
             }//9
         }//3
      }//2
      

      }//1

      if there is something unclear tell me to explain it.
      in the writing part I want to send packets.
      one of them is heart bit that I need to send it every second for wireless connection.
      and the other packets are including gps coordinates for giving missions to plane.
      I'm working on GCS for UAV. every part of program is completed but this part! and it's the most important one!

      HamedBabaeyan@yahoo.com
      for more interesting stuff

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      0
      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #9

        I suppose the communication follows a protocol like:

        • message start
        • header
        • data
        • maybe message end
          right ?

        If so you should rather use the asynchronous method, cumulate the data in a buffer and once you have a enough data, parse them and do what you must with them.

        Using a QTimer, you can send at regular interval the heat beat

        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
        1
        • HamedH Offline
          HamedH Offline
          Hamed
          wrote on last edited by
          #10

          yes this is the protocol.
          by asynchronous you mean without thread?
          I tried to do so but it has a huge delay!!
          I'm reading in 115200 baud rate from arduino (ardupilot) and I think this baud rate force me to use thread!
          Am I wrong?

          HamedBabaeyan@yahoo.com
          for more interesting stuff

          1 Reply Last reply
          0
          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #11

            No, I mean using Signals and Slots.

            The baud rate doesn't mean you need a thread, you'll have to check that once you can benchmark the load of your application. First thing to do is get the communication working, then and only then consider threading.

            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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            1
            • HamedH Offline
              HamedH Offline
              Hamed
              wrote on last edited by
              #12

              Ok I will test this once again in the morning. it's 1:00am in my country. I don't have access to arduino.
              sorry for wasting your time dear SGaist and thank you for your responses :)

              HamedBabaeyan@yahoo.com
              for more interesting stuff

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              0
              • K Offline
                K Offline
                kuzulis_
                wrote on last edited by
                #13

                Do not use it in thread if you do not know what do you do (and how it works). Please, see the QSerialPort examples and documentation, and the Qt documentation (about signals/slots, reentrant, event-loop) at first. And then, please provide a complete code how you creates and works with QSerialPort.

                Because I already see that you use QThread && QSerialPort wrong.

                by asynchronous you mean without thread?
                I tried to do so but it has a huge delay!!

                What you tried ? I do not see any code.

                HamedH 1 Reply Last reply
                1
                • K kuzulis_

                  Do not use it in thread if you do not know what do you do (and how it works). Please, see the QSerialPort examples and documentation, and the Qt documentation (about signals/slots, reentrant, event-loop) at first. And then, please provide a complete code how you creates and works with QSerialPort.

                  Because I already see that you use QThread && QSerialPort wrong.

                  by asynchronous you mean without thread?
                  I tried to do so but it has a huge delay!!

                  What you tried ? I do not see any code.

                  HamedH Offline
                  HamedH Offline
                  Hamed
                  wrote on last edited by Hamed
                  #14

                  @kuzulis_
                  Yes I used QThread and QSerialPort wrong together but it's not mean that I don't know what I'm doing!
                  I'm newbie in qt and still have trouble to use some of qt libraries.
                  but you are right. using thread was wrong at the first place! I didn't need it. Thanks to SGaist I realize it now!
                  I tried without thread before and it has delay. today I figured out using readyRead() signal is not my solution!
                  I used QTimer and 10 milliseconds for connecting to parser function(slot) and it's solved my problem for good.
                  thank you for your response. :)

                  HamedBabaeyan@yahoo.com
                  for more interesting stuff

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                  0
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #15

                    Can you show the last version of your working code ?

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

                    HamedH 1 Reply Last reply
                    0
                    • SGaistS SGaist

                      Can you show the last version of your working code ?

                      HamedH Offline
                      HamedH Offline
                      Hamed
                      wrote on last edited by SGaist
                      #16

                      @SGaist
                      of course!
                      but I cant find how to show it as code in this new forum and I also cant find solved button!
                      anyway here is the code :

                      Reader::Reader(QSerialPort *parent) :
                          QSerialPort(parent)
                      {
                          serial = new QSerialPort;
                      
                          foreach (const QSerialPortInfo &serialPortInfo, QSerialPortInfo::availablePorts())
                          serial->setPortName(serialPortInfo.portName());
                      
                          serial->setBaudRate(QSerialPort::Baud115200);
                      
                          serial->setDataBits(QSerialPort::Data8);
                      
                          serial->setParity(QSerialPort::NoParity);
                      
                          serial->setFlowControl(QSerialPort::NoFlowControl);
                      
                          serial->setStopBits(QSerialPort::OneStop);
                      
                          serial->open(QIODevice::ReadWrite);
                      
                          QTimer *timer = new QTimer(this);
                          connect(timer , SIGNAL(timeout()) , this , SLOT(read()));
                          timer->start(5);
                      }
                      
                      
                      int packet_counter = 0;
                      int rssi = 2;
                      QByteArray header;
                      QByteArray payload;
                      quint8 ID;
                      
                      void Reader::read()
                      {//1
                         if(serial->bytesAvailable() >= 10)
                         {//3
                             header = serial->read(1);
                             if(header.contains(254))
                             {//4
                                 header = serial->read(5);
                                 seq = header[1];
                                 if((header.at(2) == 01) && (header.at(3) == 01))
                                 {//7
                                     ID = header.at(4);
                                     if(seq >= 0 && seq <=254)
                                     {
                                         packet_counter++;
                                     }
                                     if(seq == 255)
                                     {
                                         packet_counter++;
                                         if(packet_counter <= 256)
                                         {
                                              rssi = (packet_counter*100)/256;
                                              emit mRssi(rssi);
                                         }
                                         packet_counter = 1;
                                     }
                                     payload = serial->read(header.at(0));
                                     switch (ID)
                                     {
                                         case (ATTITUDE) :
                                             {
                                                 mavlink_attitude_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_attitude_t));
                                                 emit attitude(data);
                                             }
                                             break;
                                         case (SCALED_PRESSURE) :
                                             {
                                                 mavlink_scaled_pressure_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_scaled_pressure_t));
                                                 emit scaled_pressure(data);
                                             }
                                             break;
                                         case (SENSOR_OFFSETS) :
                                             {
                                                 mavlink_sensor_offsets_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_sensor_offsets_t));
                                                 emit sensor_offsets(data);
                                             }
                                             break;
                                         case (SYS_STATUS) :
                                             {
                                                 mavlink_sys_status_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_system_time_t));
                                                 emit sys_status(data);
                                             }
                                             break;
                      
                                         case (GPS_RAW_INT) :
                                             {
                                                 mavlink_gps_raw_int_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_gps_raw_int_t));
                                                 emit gps_raw_int(data);
                                             }
                                             break;
                                         case (SERVO_OUTPUT_RAW) :
                                             {
                                                 mavlink_servo_output_raw_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_servo_output_raw_t));
                                                 emit servo_output_raw(data);
                                             }
                                             break;
                                         case (RC_CHANNELS_RAW) :
                                             {
                                                 mavlink_rc_channels_raw_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_rc_channels_raw_t));
                                                 emit rc_channels_raw(data);
                                             }
                                             break;
                                         case (WIND) :
                                             {
                                                 mavlink_wind_t data;
                                                 memcpy(&data,payload.data(),sizeof(mavlink_wind_t));
                                                 emit wind(data);
                                             }
                                             break;
                                     }
                                 }//7
                                 else
                                 {//8
                                     header.clear();
                                 }//8
                      
                             }//4
                             else
                             {//9
                                 header.clear();
                             }//9
                         }//3
                      }//1
                      

                      this is the reading part. I also tested writing and it's worked just fine. writing part is not complete yet. I will put that here as soon as it's completed.
                      thanks again SGaist. :)

                      [edit: Added missing coding tags SGaist]

                      HamedBabaeyan@yahoo.com
                      for more interesting stuff

                      1 Reply Last reply
                      0
                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #17

                        Why is Reader a QSerialPort ?

                        Also, your loop in the constructor opens every serial port of your computer

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

                        HamedH 1 Reply Last reply
                        1
                        • SGaistS SGaist

                          Why is Reader a QSerialPort ?

                          Also, your loop in the constructor opens every serial port of your computer

                          HamedH Offline
                          HamedH Offline
                          Hamed
                          wrote on last edited by
                          #18

                          @SGaist
                          What should it be?
                          Yes I should create a list for available ports and let user choose. it's still not complete. I should work more on details yet.

                          HamedBabaeyan@yahoo.com
                          for more interesting stuff

                          1 Reply Last reply
                          0
                          • SGaistS Offline
                            SGaistS Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on last edited by
                            #19

                            Use e.g. a default value that you know is working and add a configuration dialogue

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

                            HamedH 1 Reply Last reply
                            1
                            • SGaistS SGaist

                              Use e.g. a default value that you know is working and add a configuration dialogue

                              HamedH Offline
                              HamedH Offline
                              Hamed
                              wrote on last edited by
                              #20

                              @SGaist
                              Did it :)
                              Thank you :)

                              HamedBabaeyan@yahoo.com
                              for more interesting stuff

                              1 Reply Last reply
                              0
                              • SGaistS Offline
                                SGaistS Offline
                                SGaist
                                Lifetime Qt Champion
                                wrote on last edited by
                                #21

                                There's also QSettings to store that value so you can reuse it on next startup, that will avoid your user to change it each time they load your application if the port is not the same as yours

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

                                HamedH 1 Reply Last reply
                                1
                                • SGaistS SGaist

                                  There's also QSettings to store that value so you can reuse it on next startup, that will avoid your user to change it each time they load your application if the port is not the same as yours

                                  HamedH Offline
                                  HamedH Offline
                                  Hamed
                                  wrote on last edited by
                                  #22

                                  @SGaist
                                  I think if I store available ports string in a combo box will do this for me. right?

                                  HamedBabaeyan@yahoo.com
                                  for more interesting stuff

                                  1 Reply Last reply
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