Qt 5.13 | Qt Serial Bus | Using VectorCAN Plugin

Qt 5.13.2 Reference Documentation

# Using VectorCAN Plugin

The VectorCAN plugin encapsulates the low-level API to work with the Vector Informatik CAN adapters.

This plugin requires the Vector CAN device drivers and the vxlapi.dll (vxlapi64.dll for 64 bit builds).

## Creating CAN Bus Devices

At first it is necessary to check that QCanBus provides the desired plugin:

      if (QCanBus::instance()->plugins().contains(QStringLiteral("vectorcan"))) {
          // plugin available
      }

Where vectorcan is the plugin name.

Next, a connection to a specific interface can be established:

      QString errorString;
      QCanBusDevice *device = QCanBus::instance()->createDevice(
          QStringLiteral("vectorcan"), QStringLiteral("can0"), &errorString);
      if (!device) {
          // Error handling goes here
          qDebug << errorString;
      } else {
          device->connectDevice();
      }

Where can0 is the active CAN channel name. The VectorCAN plugin provides 64 channels (defined by XL_CONFIG_MAX_CHANNELS in the Vector API) from can0 to can63. Some of these channels can be virtual, and therefore can be used without actual CAN hardware. To find out the virtual channels, the program "Vector Hardware Config" (vcanconf.exe) can be used, which is included in Vector's driver package. The availableDevices() method returns a list of currently available devices.

The device is now open for writing and reading CAN frames:

      QCanBusFrame frame;
      frame.setFrameId(8);
      QByteArray payload("A36E");
      frame.setPayload(payload);
      device->writeFrame(frame);

The reading can be done using the readFrame() method. The framesReceived() signal is emitted when at least one new frame is available for reading:

      QCanBusFrame frame = device->readFrame();

VectorCAN supports the following configurations that can be controlled through setConfigurationParameter():

Configuration parameter key | Description
--- | ---
QCanBusDevice::BitRateKey | Determines the bit rate of the CAN bus connection.
QCanBusDevice::ReceiveOwnKey | The reception of the CAN frames on the same device that was sending the CAN frame is disabled by default. When enabling this option, all CAN frames sent to the CAN bus immediately appear in the receive buffer. This can be used to check if sending was successful. If this option is enabled, the therefore received frames are marked with QCanBusFrame::hasLocalEcho()