CAN BUS, SocketCAN cannot read CAN frames

[lakotamm]

Hi,

I have troubles reading CAN frames using readFrame() method.

My code for initialization:

#include <QCanBusFrame>
#include <QCanBus>
#include <QCanBusDevice>

CANSend::CANSend(QString interface){

    CANdevice = QCanBus::instance()->createDevice("socketcan", interface);
    if (!CANdevice->connectDevice()) {}

 }

code for sending data - everything works correctly

void CANSend::send_pos(uint16_t pos)
{
    QCanBusFrame frame;
    frame.setFrameId(1024);
    QByteArray payload;
    payload[0]=0;
    payload[1]=pos>>8;
    payload[2]=pos;

    frame.setPayload(payload);
    CANdevice->writeFrame(frame);
}

code for reading data

int CANSend::check_messages(){

     const QCanBusFrame frame = CANdevice->readFrame();

     const qint8 dataLength = frame.payload().size();

     const qint32 id = frame.frameId();

     return id;
}

during debugging I always get
frame = @0x7fffffffdf10,
dataLength = 0,
id = 0,

So, even though I can clearly see incomming packets via candump command and also in QT CANBUS example, I never receive anything.

Can you help me? Thanks.

[SGaist]

Hi and welcome to devnet,

The module being pretty new (maybe even technical preview), I'd recommend posting this question on the interest mailing list. You'll find there QtCanBus developers/maintainers. This forum is more user oriented.