Get Started with J1939 Communication in MATLAB
This example shows you how to create and use J1939 channels to transmit and receive parameter groups on a J1939 network. This example uses the database file J1939.dbc and MathWorks® virtual CAN channels connected in a loopback configuration.
Open the DBC File
Open the DBC file using canDatabase to access the definitions.
db = canDatabase("J1939.dbc")db =
Database with properties:
Name: 'J1939'
Path: 'C:\Users\michellw\OneDrive - MathWorks\Documents\MATLAB\Examples\vnt-ex33605241\J1939.dbc'
Nodes: {2×1 cell}
NodeInfo: [2×1 struct]
Messages: {2×1 cell}
MessageInfo: [2×1 struct]
Attributes: {3×1 cell}
AttributeInfo: [3×1 struct]
UserData: []
Create the J1939 Channels
Use the function j1939Channel to create J1939 channels on which you can send and receive information.
txCh = j1939Channel(db, "MathWorks", "Virtual 1", 1)
txCh =
Channel with properties:
Device Information:
-------------------
DeviceVendor: 'MathWorks'
Device: 'Virtual 1'
DeviceChannelIndex: 1
DeviceSerialNumber: 0
Data Details:
-------------
ParameterGroupsAvailable: 0
ParameterGroupsReceived: 0
ParameterGroupsTransmitted: 0
FilterPassList: []
FilterBlockList: []
Channel Information:
--------------------
Running: 0
BusStatus: 'N/A'
InitializationAccess: 1
InitialTimestamp: [0×0 datetime]
SilentMode: 0
TransceiverName: 'N/A'
TransceiverState: 'N/A'
BusSpeed: 500000
SJW: []
TSEG1: []
TSEG2: []
NumOfSamples: []
Other Information:
------------------
UserData: []
rxCh = j1939Channel(db, "MathWorks", "Virtual 1", 2)
rxCh =
Channel with properties:
Device Information:
-------------------
DeviceVendor: 'MathWorks'
Device: 'Virtual 1'
DeviceChannelIndex: 2
DeviceSerialNumber: 0
Data Details:
-------------
ParameterGroupsAvailable: 0
ParameterGroupsReceived: 0
ParameterGroupsTransmitted: 0
FilterPassList: []
FilterBlockList: []
Channel Information:
--------------------
Running: 0
BusStatus: 'N/A'
InitializationAccess: 1
InitialTimestamp: [0×0 datetime]
SilentMode: 0
TransceiverName: 'N/A'
TransceiverState: 'N/A'
BusSpeed: 500000
SJW: []
TSEG1: []
TSEG2: []
NumOfSamples: []
Other Information:
------------------
UserData: []
Create the J1939 Parameter Groups
Use the function j1939ParameterGroup to create a single-frame parameter group to send on the network.
pgSingleFrame = j1939ParameterGroup(db, "VehicleDataSingle")pgSingleFrame =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 6
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 254
DestinationAddress: 254
Data Details:
-------------
Timestamp: 0
Data: [255 255 255 255 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
Set transmission details and signal data.
pgSingleFrame.SourceAddress = 30; pgSingleFrame.DestinationAddress = 50; pgSingleFrame.Signals.VehicleSignal1 = 25; pgSingleFrame.Signals.VehicleSignal2 = 1000; pgSingleFrame.Signals
ans = struct with fields:
VehicleSignal4: -1
VehicleSignal3: -1
VehicleSignal2: 1000
VehicleSignal1: 25
Using the same approach, create a multi-frame parameter group, then set transmission details and signal data.
pgMultiFrame = j1939ParameterGroup(db, "VehicleDataMulti")pgMultiFrame =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataMulti'
PGN: 51200
Priority: 6
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 254
DestinationAddress: 254
Data Details:
-------------
Timestamp: 0
Data: [255 255 255 255 255 255 255 255 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pgMultiFrame.SourceAddress = 30; pgMultiFrame.DestinationAddress = 255; pgMultiFrame.Signals.VehicleSignal1 = 5; pgMultiFrame.Signals.VehicleSignal2 = 650; pgMultiFrame.Signals.VehicleSignal3 = 5000; pgMultiFrame.Signals
ans = struct with fields:
VehicleSignal6: -1
VehicleSignal5: -1
VehicleSignal4: -1
VehicleSignal3: 5000
VehicleSignal2: 650
VehicleSignal1: 5
Start the J1939 Channels
Use the function start to start the J1939 channels for transmit and receive operations.
start(rxCh); start(txCh);
Send J1939 Parameter Groups
The transmit function sends parameter groups onto the network. The J1939 channel automatically sends parameter groups requiring multi-frame messaging via its transport protocol.
transmit(txCh, pgSingleFrame) transmit(txCh, pgSingleFrame) transmit(txCh, pgMultiFrame) transmit(txCh, pgSingleFrame) transmit(txCh, pgSingleFrame) pause(2);
Receive the Parameter Groups
The receive function retrieves information from the channel which represents messaging that occurred on the network.
pgRx = receive(rxCh, Inf)
pgRx=5×8 timetable
Time Name PGN Priority PDUFormatType SourceAddress DestinationAddress Data Signals
___________ _________________ _____ ________ _____________________ _____________ __________________ ____________________________________________ ____________
0.13955 sec VehicleDataSingle 40192 6 Peer-to-Peer (Type 1) 30 50 {[ 25 0 232 3 255 255 255 255]} {1×1 struct}
0.14347 sec VehicleDataSingle 40192 6 Peer-to-Peer (Type 1) 30 50 {[ 25 0 232 3 255 255 255 255]} {1×1 struct}
0.59386 sec VehicleDataMulti 51200 6 Peer-to-Peer (Type 1) 30 255 {[5 0 138 2 136 19 255 255 255 255 255 255]} {1×1 struct}
0.76564 sec VehicleDataSingle 40192 6 Peer-to-Peer (Type 1) 30 50 {[ 25 0 232 3 255 255 255 255]} {1×1 struct}
0.7702 sec VehicleDataSingle 40192 6 Peer-to-Peer (Type 1) 30 50 {[ 25 0 232 3 255 255 255 255]} {1×1 struct}
Inspect Received Parameter Groups Signals
View details of the received signals for an instance of the single-frame and the multiframe parameter group.
pgRx.Signals{1}ans = struct with fields:
VehicleSignal4: -1
VehicleSignal3: -1
VehicleSignal2: 1000
VehicleSignal1: 25
pgRx.Signals{3}ans = struct with fields:
VehicleSignal6: -1
VehicleSignal5: -1
VehicleSignal4: -1
VehicleSignal3: 5000
VehicleSignal2: 650
VehicleSignal1: 5
Access Signal Values
The j1939SignalTimetable function allows you to easily extract and transform signal data from a timetable of parameter groups.
sigTT = j1939SignalTimetable(pgRx)
sigTT = struct with fields:
VehicleDataMulti: [1×6 timetable]
VehicleDataSingle: [4×4 timetable]
sigTT.VehicleDataSingle
ans=4×4 timetable
Time VehicleSignal4 VehicleSignal3 VehicleSignal2 VehicleSignal1
___________ ______________ ______________ ______________ ______________
0.13955 sec -1 -1 1000 25
0.14347 sec -1 -1 1000 25
0.76564 sec -1 -1 1000 25
0.7702 sec -1 -1 1000 25
sigTT.VehicleDataMulti
ans=1×6 timetable
Time VehicleSignal6 VehicleSignal5 VehicleSignal4 VehicleSignal3 VehicleSignal2 VehicleSignal1
___________ ______________ ______________ ______________ ______________ ______________ ______________
0.59386 sec -1 -1 -1 5000 650 5
Stop the J1939 Channels
To stop receiving data from the network, stop the J1939 channels using the stop function.
stop(rxCh); stop(txCh);
