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Diagnostic Samples

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Two different projects, Diagnostics Sample and SIL Diag Sample, show a couple of the many approaches that can be taken when testing CAN diagnostic features.

•Diagnostics Sample uses a quick and easy method by setting up Transport Protocol messages directly from Signal Dictionary to send/receive diagnostic messages.

•SIL Diag Sample shows a more comprehensive approach by creating separate signals for different Diagnostic Functions and using the SIL Easy Transform to re-use C code for Seed/Key Security Algorithm functionality.

Click here to download the project: https://github.com/DanlawMxTeam/Samples/raw/master/DiagnosticsSample.rar

This sample project demonstrates using the Diagnostics protocol with MxVDev. Normally diagnostics are used with a hardware ECU, but for purposes of this sample, the ECU is simulated by a MxVMC Transform.

The project contains one CAN bus named “Diagnostic CAN Bus”.

There are 3 Transport Protocol Signals defined on this bus:

•Diagnostic Transmit – used to send diagnostic messages to the ECU. This Signal is received by the Transport Request Transform.

•Diagnostic Receive – used to receive diagnostic messages from the ECU. This Signal is read from the CAN bus and transmitted from the outport of the Transport Response Transform.

•Functional Transmit – used to send Functional Requests to all the ECUs connected on the bus. This Signal is used for the Tester Present message. It is received by the Transport Request Transform.

These Signals are defined by the Transforms and exported. The CAN IDs used are specified in the Transforms' properties as shown here:

Transport Request Transform Properties

Transport Response Transform Properties

These are ECU specific, and one can easily change them in the Harness Transform properties. The same strategy can be adopted for a HIL set up where a virtual bus is connected to a physical CAN bus with a real ECU. See Connecting to a Hardware Bus.

The Scenario does the following:

•Initializes the ECU (resets values in the AppIF.c)

•Starts the tick for the VMC

•Start the Tester Present (sends a Tester Present message every 100ms over the Functional Transmit signal)

•Enters in different diagnostic sessions

Diagnostic Sample Harness

The Transport Request Transform receives messages from the TestCases and transmits them in ISO15765 transport protocol. The message pass through the Delay and Funnel Transforms to the ECU simulated by the VMC.

The VMC receives Enter Session messages and sends a response to the CAN Network and through the Delay Transform to the Transport Response Transform.

The Transport Response Transform receives CAN frames and assembles the TP message, which is transmitted to the Enter Diagnostic Session TestCase.

The Sil\DiagSample project shows a SIL Easy Transform used in a more complex Harness. It demonstrates using SIL Easy for a security algorithm, using Transport Protocol (TP) Transforms, Diagnostic Transforms, and routing data to a virtual ECU.

Click here to download the project: https://github.com/DanlawMxTeam/Samples/raw/master/SilEasySamples.rar

The project is in the Sil/DiagSample/MxVDev subfolder.

This sample includes :

•One Scenario and 3 TestCases

•A custom Harness. Details below.

The TestCases do the following:

•Init - Initializes the VMC and SIL Easy Transforms

•Tick - Ticks the VMC

•Test Diag Functions:

oStarts the Tester Present from the Transport Request Transform

oSends Diagnostic Request messages and reads and checks Diagnostic Response messages

oThe probes display the messages going into and out of the VMC

You may need to use the MSVS conversion wizard and convert the solution to run the sample. See Retargeting a Visual Studio solution.

This project is designed to pass.

SIL Diag Sample Harness

Harness Details

Transport Request and Transport Response Transforms are used with transport protocol ISO15765 to send and receive data that is longer than a standard 8-byte CAN message. Transport Request breaks TP messages into standard CAN frames and Transport Response receives CAN frames and assembles the TP message. Set desired CAN Arbitration IDs in properties for proper execution. The Tester Present Signal can be used to turn on and off sending of the Tester Present Keep Alive Message.

Diagnostic Request and Response Transforms are used to create a separate Signal for any desired Diagnostic function for further customization. For example, KWP2000 Diagnostic function $10 to start Diagnostic Session can exist as its own signal ('Service $10 Req') in the TestCase, and a value passed into the Transform for the desired session will build the proper CAN message to send to the ECU under test.

The SIL Easy Transform is used to calculate the 'key' based on incoming 'seed' value. Using SIL Easy requires minimum effort to create a block that uses your existing C/C++ code. Place the Transform on the graph, click 'Create New Project' in properties. Copy/Paste your code into source files or add your source files to the Visual Studio project. Harness two signals as Input and Output messages (buffers). In the example shown, a 3 byte message is used where the first byte corresponds to 'security mode' and the next two bytes store the value for seed or key. The seed value comes from Diagnostic Response to the request to send seed. When the value is received, the corresponding key is calculated and routed to the Request transforms to send the request to unlock the security mode. The Transform's IsSut property in this example is set to operate as a Connector Transform.

Funnel Transforms are helper Transforms that are used when messages from 2 or more different sources need to be connected to one.

PassThru Transforms are used when Signals from one source need to be sent to identical Signals in sink transforms (i.e. 'MxV Module Reset')

Delay Transforms are used when signals from the output side of the graph need to be routed as an input to the beginning/'start' of the graph to help determine the sequence of execution.

The MxVMC Transform is used as an ECU under test for Software-in-the-Loop. The same approach shown in the sample can be used to test Hardware-in-the-Loop ECU when the virtual bus is connected to the hardware CAN bus. The Transform's IsSut property in this example is set to operate as a Connector Transform.