QTimers and QThreads

TMJJ001

Dear all,

I'm writing an application which makes use of QTimers, QThreads and Socket_CAN.

I have a main visualization, I need to send at a certain timing a CANbus message and I want to read the data traffic on the bus at all times. So what I did:

My main application which runs the visualization.
CANopen Object.

Please see code below.

#include "canopen.h"

CANOpen::CANOpen(QObject *parent) : QObject(parent)
{
    NMT_timer = new QTimer(this);
    connect(NMT_timer,SIGNAL(timeout()),this,SLOT(NMT_Send()));
    
    // initialize CAN socket
    int com_error;
    com_error = can_socket->open_port("can0",0);
    if(com_error<0)
    {
        qDebug() << "E301: Internal Error: Unable to open CAN SOCKET. NO Communication possible" + QString::number(com_error);
    }
    
    // Start to send CANbus message at certain timing (800ms)
    NMT_timer->start(800);
    iStep = 0;
}

void CANOpen::canopen_init(QString canbus, int filter)
{

}

void CANOpen::DoSetup(QThread &cThread)
{
    // Setup thread. Function is called when a button is pushed
    connect(&cThread,SIGNAL(started()),this,SLOT(DoWork()));
}

void CANOpen::DoWork()
{
    // Read traffic on CANbus 
    qDebug() << "read port";
    while(1){
        can_socket->read_port();
    }
}

void CANOpen::NMT_Send()
{
    // Send message on CANbus 
    qDebug() << "NMT message";

    can_frame NMT_message;
    NMT_message.can_id = 0x701;
    NMT_message.can_dlc = 1;
    NMT_message.data[0] = 0x7F;
    can_socket->send_port(NMT_message);

}

So what is happening now:

The application starts up and start to send messages on the CANbus every 800ms. So so far so good.
Then I push the button, so the DoWork function is called. The thread is started and I can read every message on the CANbus.
The only issue at this moment is that no messages are send on the CANbus anymore. I suppose the Thread block the timer to run. (The main application continues with out any issue)
Is this correct? Ifso, how can I solve this please?

Thanks in advance,
Kind regards,
TMJJ

jsulm

@TMJJ001 said in QTimers and QThreads:

connect(&cThread,SIGNAL(started()),this,SLOT(DoWork()));

You do NOT execute DoWork() in that thread, you execute it in the GUI thread.
Take a closer look at the example here: https://doc.qt.io/qt-5/qthread.html