canMessage

Build CAN message based on user-specified structure

Syntax

message = canMessage(id,extended,datalength)

message = canMessage(id,extended,datalength,'ProtocolMode','CAN FD')

message = canMessage(candb,messagename)

Description

message = canMessage(id,extended,datalength) creates a CAN message object from the raw message information.

message = canMessage(id,extended,datalength,'ProtocolMode','CAN FD') creates a CAN FD message. The default ProtocolMode is standard 'CAN'.

message = canMessage(candb,messagename) creates a message using the message definition in the specified database. Because ProtocolMode is defined in the message database, you cannot specify it as an argument to canMessage when using a database.

Examples

Create a CAN Message

Create a CAN message with an extended ID format.

message1 = canMessage(2500,true,4)

message1 = 

  Message with properties:

   Message Identification
    ProtocolMode: 'CAN'
              ID: 5000
        Extended: 1
            Name: ''

   Data Details
       Timestamp: 0
            Data: [0 0 0 0]
         Signals: []
          Length: 4

   Protocol Flags
           Error: 0
          Remote: 0

   Other Information
        Database: []
        UserData: []

Create a CAN FD Message

Create a CAN FD message with a standard ID format.

message2 = canMessage(1000,false,64,'ProtocolMode','CAN FD')

message2 = 

  Message with properties:

   Message Identification
    ProtocolMode: 'CAN FD'
              ID: 1000
        Extended: 0
            Name: ''

   Data Details
       Timestamp: 0
            Data: [1×64 uint8]
         Signals: []
          Length: 64
             DLC: 15

   Protocol Flags
             BRS: 0
             ESI: 0
           Error: 0

   Other Information
        Database: []
        UserData: []

Create a Message with Database Definitions

Create a message using the definitions of a CAN database.

candb = canDatabase(string([(matlabroot) '\examples\vnt\VehicleInfo.dbc']))
message3 = canMessage(candb,'WheelSpeeds')

message3 = 

  Message with properties:

   Message Identification
    ProtocolMode: 'CAN'
              ID: 1200
        Extended: 0
            Name: 'WheelSpeeds'

   Data Details
       Timestamp: 0
            Data: [0 0 0 0 0 0 0 0]
         Signals: [1×1 struct]
          Length: 8

   Protocol Flags
           Error: 0
          Remote: 0

   Other Information
        Database: [1×1 can.Database]
        UserData: []

Input Arguments

id — ID of message

numeric value

ID of the message, specified as a numeric value. If this ID used an extended format, set the extended argument true.

Example: 2500

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

extended — Indicate if message ID is extended

true | false

Indicates whether the message ID is of standard or extended type, specified as true or false. The logical value true indicates that the ID is of extended type, false indicates standard type.

Example: true

Data Types: logical

datalength — Length of message data

integer value 0-8

The length of the message data, specified as an integer value of 0 through 8, inclusive.

Example: 8

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

candb — CAN database

CAN database object

CAN database, specified as a database object. The database contains the message definition.

Example: candb = canDatabase('J1939.dbc')

messagename — Name of message

char vector | string

The name of the message definition in the database, specified as a character vector or string.

Example: 'VehicleDataMulti'

Data Types: char | string

Output Arguments

message — CAN message

CAN message object

CAN message, returned as a CAN message object, with the following properties:

Property	Purpose
BRS	CAN FD bit rate switch, as true or false
Data	Data of CAN message or J1939 parameter group
Database	CAN database information
DLC	Data length code value
Error	CAN message error frame, as true or false
ESI	CAN FD error state indicator, as true or false
Extended	True of false indication of extended CAN Identifier type
ID	Identifier for CAN message
Length	Message length in bytes
Name	CAN message name
ProtocolMode	Protocol mode defined as CAN or CAN FD
Remote	Specify if CAN message is remote frame
Signals	Physical signals defined in CAN message or J1939 parameter group
Timestamp	Message received timestamp
UserData	Custom data