Get Started with CAN FD Communication in MATLAB

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This example shows you how to use CAN FD channels to transmit and receive CAN FD messages. It uses MathWorks virtual CAN FD channels connected in a loopback configuration.

View Available CAN FD Channels

Use canFDChannelList to see all available device channels supporting CAN FD.

canFDChannelList

ans=2×6 table
      Vendor         Device       Channel    DeviceModel    ProtocolMode     SerialNumber
    ___________    ___________    _______    ___________    _____________    ____________

    "MathWorks"    "Virtual 1"       1        "Virtual"     "CAN, CAN FD"        "0"     
    "MathWorks"    "Virtual 1"       2        "Virtual"     "CAN, CAN FD"        "0"

Create Transmitting and Receiving Channels

Use canFDChannel with device details specified to create CAN FD channels for transmitting and receiving messages.

txCh = canFDChannel("MathWorks", "Virtual 1", 1)

txCh = 
  Channel with properties:

   Device Information
            DeviceVendor: 'MathWorks'
                  Device: 'Virtual 1'
      DeviceChannelIndex: 1
      DeviceSerialNumber: 0
            ProtocolMode: 'CAN FD'

   Status Information
                 Running: 0
       MessagesAvailable: 0
        MessagesReceived: 0
     MessagesTransmitted: 0
    InitializationAccess: 1
        InitialTimestamp: [0x0 datetime]
           FilterHistory: 'Standard ID Filter: Allow All | Extended ID Filter: Allow All'

   Bit Timing Information
               BusStatus: 'N/A'
              SilentMode: 0
         TransceiverName: 'N/A'
        TransceiverState: 'N/A'
       ReceiveErrorCount: 0
      TransmitErrorCount: 0
     ArbitrationBusSpeed: []
            DataBusSpeed: []

   Other Information
                Database: []
                UserData: []

rxCh = canFDChannel("MathWorks", "Virtual 1", 2);

Configure Bus Speed

CAN FD channels require setting of bus speed before going online. Both the arbitration and data phase speeds are configured using configBusSpeed.

configBusSpeed(txCh, 500000, 1000000);
configBusSpeed(rxCh, 500000, 1000000);

Open the DBC-File

Use canDatabase to open the database file that contains definitions of CAN FD messages and signals.

db = canDatabase("CANFDExample.dbc")

db = 
  Database with properties:

             Name: 'CANFDExample'
             Path: '/tmp/Bdoc22a_1891349_157288/tpe433a46b/vnt-ex36915890/CANFDExample.dbc'
        UTF8_File: '/tmp/Bdoc22a_1891349_157288/tpe433a46b/vnt-ex36915890/CANFDExample.dbc'
            Nodes: {}
         NodeInfo: [0x0 struct]
         Messages: {'CANFDMessage'}
      MessageInfo: [1x1 struct]
       Attributes: {2x1 cell}
    AttributeInfo: [2x1 struct]
         UserData: []

Attach the database directly to the receiving channel. Definitions from the DBC-files are applied automatically to decode incoming messages and signals.

rxCh.Database = db;

Start the Channels

Use the start command to set the channels online.

start(txCh);
start(rxCh);

Create CAN FD Messages

Create CAN FD messages using the canFDMessage function.

msg1 = canFDMessage(500, false, 12)

msg1 = 
  Message with properties:

   Message Identification
    ProtocolMode: 'CAN FD'
              ID: 500
        Extended: 0
            Name: ''

   Data Details
       Timestamp: 0
            Data: [0 0 0 0 0 0 0 0 0 0 0 0]
         Signals: []
          Length: 12
             DLC: 9

   Protocol Flags
             BRS: 0
             ESI: 0
           Error: 0

   Other Information
        Database: []
        UserData: []

msg2 = canFDMessage(1000, false, 24);
msg3 = canFDMessage(1500, false, 64);

To engage the bit rate switch capability of CAN FD, set the BRS property of the messages.

msg1.BRS = true;
msg2.BRS = true;
msg3.BRS = true;

CAN FD messages can also be created using a database. The database defines if a message is CAN or CAN FD as well as the BRS status.

msg4 = canFDMessage(db, "CANFDMessage")

msg4 = 
  Message with properties:

   Message Identification
    ProtocolMode: 'CAN FD'
              ID: 1
        Extended: 0
            Name: 'CANFDMessage'

   Data Details
       Timestamp: 0
            Data: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ... ]
         Signals: []
          Length: 48
             DLC: 14

   Protocol Flags
             BRS: 1
             ESI: 0
           Error: 0

   Other Information
        Database: [1x1 can.Database]
        UserData: []

Transmit Messages

Use transmit to send the created messages from the transmitting channel.

transmit(txCh, [msg1 msg2 msg3 msg4])

Receive Messages

Receive the messages from the receiving channel using the receive function. The default return type for CAN FD channels is a timetable containing information specific to the received CAN FD messages.

rxMsg = receive(rxCh, Inf)

rxMsg=4×12 timetable
       Time         ID     Extended          Name          ProtocolMode                                       Data                                       Length    DLC      Signals       Error    Remote     BRS      ESI 
    ___________    ____    ________    ________________    ____________    __________________________________________________________________________    ______    ___    ____________    _____    ______    _____    _____

    0.14632 sec     500     false      {0x0 char      }     {'CAN FD'}     {[                                               0 0 0 0 0 0 0 0 0 0 0 0]}      12       9     {0x0 struct}    false    false     true     false
    0.14632 sec    1000     false      {0x0 char      }     {'CAN FD'}     {[                       0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]}      24      12     {0x0 struct}    false    false     true     false
    0.14632 sec    1500     false      {0x0 char      }     {'CAN FD'}     {[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ... ]}      64      15     {0x0 struct}    false    false     true     false
    0.14632 sec       1     false      {'CANFDMessage'}     {'CAN FD'}     {[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ... ]}      48      14     {1x1 struct}    false    false     true     false

Stop the Channels

Use the stop command to set the channels offline.

stop(txCh);
stop(rxCh);

Close the DBC-File

Close access to the DBC-file by clearing its variable from the workspace.

clear db