Qt Documentation

Filter Class

(QCanBusDevice::Filter)

The QCanBusDevice::Filter struct defines a filter for CAN bus frames. More...

Header:	#include <Filter>
qmake:	QT += serialbus
Since:	Qt 5.8

List of all members, including inherited members

Public Types

enum	FormatFilter { MatchBaseFormat, MatchExtendedFormat, MatchBaseAndExtendedFormat }
flags	FormatFilters

Public Variables

QCanBusDevice::Filter::FormatFilter	format
quint32	frameId
quint32	frameIdMask
QCanBusFrame::FrameType	type

Detailed Description

The QCanBusDevice::Filter struct defines a filter for CAN bus frames.

A list of QCanBusDevice::Filter instances is passed to QCanBusDevice::setConfigurationParameter() to enable filtering. If a received CAN frame matches at least one of the filters in the list, the QCanBusDevice will accept it.

The example below demonstrates how to use the struct:

QCanBusDevice::Filter filter;
QList<QCanBusDevice::Filter> filterList;

// filter all CAN bus packages with id 0x444 (base) or 0xXXXXX444 (extended)
filter.frameId = 0x444u;
filter.frameIdMask = 0x7FFu;
filter.format = QCanBusDevice::Filter::MatchBaseAndExtendedFormat;
filter.type = QCanBusFrame::InvalidFrame;
filterList.append(filter);

// filter all DataFrames with extended CAN bus package format
filter.frameId = 0x0;
filter.frameIdMask = 0x0;
filter.format = QCanBusDevice::Filter::MatchExtendedFormat;
filter.type = QCanBusFrame::DataFrame;
filterList.append(filter);

// apply filter
device->setConfigurationParameter(QCanBusDevice::RawFilterKey, QVariant::fromValue(filterList));

Member Type Documentation

enum Filter::FormatFilter
flags Filter::FormatFilters

This enum describes the format pattern, which is used to filter incoming CAN bus frames.

Constant	Value	Description
`QCanBusDevice::Filter::MatchBaseFormat`	`0x0001`	The CAN bus frame must use the base frame format (11 bit identifier).
`QCanBusDevice::Filter::MatchExtendedFormat`	`0x0002`	The CAN bus frame must use the extended frame format (29 bit identifier).
`QCanBusDevice::Filter::MatchBaseAndExtendedFormat`	`0x0003`	The CAN bus frame can have a base or an extended frame format.

The FormatFilters type is a typedef for QFlags<FormatFilter>. It stores an OR combination of FormatFilter values.

Member Variable Documentation

QCanBusDevice::Filter::FormatFilter Filter::format

This variable holds the frame format of the matching CAN bus frame.

By default this field is set to QCanBusDevice::Filter::MatchBaseAndExtendedFormat.

quint32 Filter::frameId

This variable holds the frame id used to filter the incoming frames.

The frameId is used in conjunction with frameIdMask. The matching is successful if the following evaluates to true:

(receivedFrameId & frameIdMask) == (frameId & frameIdMask)

By default this field is set to 0x0.

See also frameIdMask.

quint32 Filter::frameIdMask

This variable holds the bit mask that is applied to the frame id of the filter and the received frame.

The two frame ids are matching if the following evaluates to true:

(receivedFrameId & frameIdMask) == (frameId & frameIdMask)

By default this field is set to 0x0.

See also frameId.

QCanBusFrame::FrameType Filter::type

This variable holds the type of the frame to be filtered.

Any CAN bus frame type can be matched by setting this variable to QCanBusFrame::InvalidFrame. The filter object is invalid if type is equal to QCanBusFrame::UnknownFrame.

By default this field is set to QCanBusFrame::InvalidFrame.

See also QCanBusFrame::FrameType.

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