Get Started with ARXML Files

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This example shows you how to parse and view the information in an ARXML file.

Access is provided via an ARXML file object. The ARXML file object can be used for:

  • Input for the raw message decoding methods.

  • Observing the missing elements that could cause a decode failure.

  • Finding the information about the messages, PDUs, or Signals of interest.

  • Understanding the formation of the ARXML file.

This example describes the situation for CAN.

Open the ARXML File

Open the example file SampleFile.arxml using arxmlDatabase MATLAB function. The ARXML File Object includes three properties, the Name, Path and CAN. 

arxmlObj = arxmlDatabase("SampleFile.arxml")
arxmlObj = 
  Database with properties:

    Name: "SampleFile.arxml"
    Path: "/tmp/Bdoc25a_2864802_1971459/tpcbc94420/vnt-ex86715502/SampleFile.arxml"
     CAN: [1×1 shared.vnt.arxml.protocol.CAN]

View the Entity Values from the ARXML File

The CAN property is an object containing CAN-protocol-specific ARXML information. Currently, only the CAN protocol is supported, and all information within the object is read-only.

The CAN object includes three properties: Frame, PDU, and ISignal, reflecting the basic structure of the ARXML file.

arxmlObj.CAN
ans = 
  CAN with properties:

      Frame: [2×9 table]
        PDU: [1×1 shared.vnt.arxml.shared.PDU]
    ISignal: [6×9 table]

View Frame Information

Call the Frame property to view the Frame table. 

arxmlObj.CAN.Frame
ans=2×9 table
        Name                    Path                  ID     Extended    StartBit    Length           ByteOrder                         PDU                     FrameTriggering  
    ____________    _____________________________    ____    ________    ________    ______    _______________________    ________________________________    ___________________

    "ML_Frame_1"    "/MathWorks/FRAME/ML_Frame_1"    1000     false         0          8       mostSignificantByteLast    /MathWorks/PDUS/ML_ISignalIPDU_1    "FrameTriggering_1"
    "ML_Frame_2"    "/MathWorks/FRAME/ML_Frame_2"    1001     true          0          4       mostSignificantByteLast    /MathWorks/PDUS/ML_ISignalIPDU_2    "FrameTriggering_2"

The Frame table includes the information defined in ARXML file for CAN. This table includes all the information required to decode CAN Frames to ISignalIPDUs.

The table defines the terms following the AUTOSAR standard.

  • Path reflects the hierarchical organization from top to bottom, illustrating how elements are contained within each other.

  • PDU (Protocol Data Unit) is a data packet used for communication between software components and ECUs. It uses the same representation as Path in the table.

  • FrameTriggering defines the timing and conditions under which the Frame is sent or received on a network.

  • ByteOrder reflects the endianess. It uses the term mostSignificantByteLast (Little Endian) and mostSignificantByteFirst (Big Endian).

View PDU Information

Call the PDU property to view the PDU information for CAN. The PDU is an object with various types of PDUs as properties. Currently, only ISignalIPDU is supported.

arxmlObj.CAN.PDU
ans = 
  PDU with properties:

    ISignalIPDU: [2×6 table]

Call the ISignalIPDU to view the ISignalIPDU table. 

arxmlObj.CAN.PDU.ISignalIPDU
ans=2×6 table
           Name                      Frame                 ISignal      StartBit    Length           ByteOrder       
    __________________    ___________________________    ___________    ________    ______    _______________________

    "ML_ISignalIPDU_1"    /MathWorks/FRAME/ML_Frame_1    {4×5 table}       0          8       mostSignificantByteLast
    "ML_ISignalIPDU_2"    /MathWorks/FRAME/ML_Frame_2    {2×5 table}       0          4       mostSignificantByteLast

The ISignalIPDU table includes the ISignalIPDU information defined in ARXML file for CAN. The ISignal column lists the ISignals contained within a specific ISignalIPDU.

arxmlObj.CAN.PDU.ISignalIPDU.ISignal{1}
ans=4×5 table
         Name         StartBit    Length           ByteOrder              BaseType  
    ______________    ________    ______    ________________________    ____________

    "ML_ISignal_1"       0          1       mostSignificantByteLast     {1×1 struct}
    "ML_ISignal_2"       1          2       mostSignificantByteFirst    {1×1 struct}
    "ML_ISignal_3"       3          2       opaque                      {1×1 struct}
    "ML_ISignal_4"       5          1       mostSignificantByteLast     {1×1 struct}


arxmlObj.CAN.PDU.ISignalIPDU.ISignal{2}
ans=2×5 table
         Name         StartBit    Length           ByteOrder             BaseType  
    ______________    ________    ______    _______________________    ____________

    "ML_ISignal_5"        0          2      mostSignificantByteLast    {1×1 struct}
    "ML_ISignal_6"      NaN        NaN      mostSignificantByteLast    {1×1 struct}

This ISignal table includes the basic information, such as the bit position of the ISignal in the ISignalIPDU. Complete ISignal information is available in the ISignal table.

View ISignal Information

Call the ISignal property to view the ISignal table. 

arxmlObj.CAN.ISignal
ans=6×9 table
         Name                             CompuMethod                        StartBit    Length           ByteOrder              BaseType         Unit                      PDU                                    SystemSignal                  
    ______________    ___________________________________________________    ________    ______    ________________________    ____________    ___________    ________________________________    _______________________________________________

    "ML_ISignal_1"    1×1 shared.vnt.arxml.shared.compumethod.CompuMethod        0          1      mostSignificantByteLast     {1×1 struct}    F              /MathWorks/PDUS/ML_ISignalIPDU_1    "/MathWorks/SYSTEM_SIGNALS/ML_ISignal_1_System"
    "ML_ISignal_2"    1×1 shared.vnt.arxml.shared.compumethod.CompuMethod        1          2      mostSignificantByteFirst    {1×1 struct}    min            /MathWorks/PDUS/ML_ISignalIPDU_1    "/MathWorks/SYSTEM_SIGNALS/ML_ISignal_2_System"
    "ML_ISignal_3"    1×1 shared.vnt.arxml.shared.compumethod.CompuMethod        3          2      opaque                      {1×1 struct}    rpm            /MathWorks/PDUS/ML_ISignalIPDU_1    "/MathWorks/SYSTEM_SIGNALS/ML_ISignal_3_System"
    "ML_ISignal_4"    1×1 shared.vnt.arxml.shared.compumethod.CompuMethod        5          1      mostSignificantByteLast     {1×1 struct}    F              /MathWorks/PDUS/ML_ISignalIPDU_1    "/MathWorks/SYSTEM_SIGNALS/ML_ISignal_4_System"
    "ML_ISignal_5"    1×1 shared.vnt.arxml.shared.compumethod.CompuMethod        0          2      mostSignificantByteLast     {1×1 struct}    F              /MathWorks/PDUS/ML_ISignalIPDU_2    "/MathWorks/SYSTEM_SIGNALS/ML_ISignal_5_System"
    "ML_ISignal_6"    1×1 shared.vnt.arxml.shared.compumethod.CompuMethod      NaN        NaN      mostSignificantByteLast     {1×1 struct}    <undefined>    /MathWorks/PDUS/ML_ISignalIPDU_2    ""

The CompuMethod column displays the CompuMethod object, allowing you to view the properties of supported CompuMethods. More details will be provided if we call the item in the table.

For example, ISignal "ML_ISignal_2" uses a CompuMethod of the type TextTable. 

arxmlObj.CAN.ISignal.CompuMethod(2)
ans = 
  TextTable with properties:

            Name: "ML_ISignal_2_Encoding"
            Unit: "min"
              VT: ["Group1"    "Group2"    "Group3"]
      LowerLimit: [1 2 3]
      UpperLimit: [1 2 3]
    DefaultValue: ""
    InverseValue: [NaN NaN NaN]

The BaseType column displays the information of the physical data type. It specifies the encoding method and size of the data. 

arxmlObj.CAN.ISignal.BaseType{1}
ans = struct with fields:
    BaseTypeEncoding: 'NONE'
        BaseTypeSize: 16

Missing Elements

In ARXML, certain elements are optional. If they are not defined in the file, they might be absent from the ARXML file object table.

Different datatypes have different representation of "missing" in the table. 

arxmlObj.CAN.ISignal(6,:)
ans=1×9 table
         Name                          CompuMethod                     StartBit    Length           ByteOrder             BaseType         Unit                      PDU                   SystemSignal
    ______________    _____________________________________________    ________    ______    _______________________    ____________    ___________    ________________________________    ____________

    "ML_ISignal_6"    1×1 shared.vnt.arxml.shared.compumethod.Empty      NaN        NaN      mostSignificantByteLast    {1×1 struct}    <undefined>    /MathWorks/PDUS/ML_ISignalIPDU_2         ""