Using NI-VCOM Toolkit 2025 Q3 or newer to Implement the Custom Checksum for CAN Application

Starting from Vehicle Communication Toolkit 2025 Q3, the new PSPRFM (pre send post receive frame manipulation) module is implemented to calculate custom checksum. This page will introduce how to implement the custom checksum with the new module.

1. Setup the compiling toolchain Using NI Linux Real-Time Cross Compile Toolchain with Visual Studio Code for Linux RT and Generating a Windows Dll File for Custom Checksum with Visual Studio for Windows.
2. Prepare the C code file "RCPSPRFM_Module.cpp" that contains your checksum (CRC) algorithm. The following code is an example of a checksum algorithm.  The checksum signal is byte0 and checksum algorithm is to add all the other bytes.

In the second if condition, "pEvent->event.msg.m_uIdc == 0x1D1" means that only the frame 0x1D1 will implement this checksum algorithm. Without it, the specific checksum algorithm will be implemented to all the transmission frames.

3. For Linux RT, Compile the RCPSPRFM_Module.cpp to libTbPSPRFMtest.so without any errors.

The so file can be found in the folder "......\build\bin\"

For Windows, Compile the RCPSPRFM_Module.cpp to a dll file. The dll file can be found in the folder "......\x64\Release\".

4. For Linux RT, put the attached libTbPSPRFMtest.dll file to the folder "<VeriStand project folder>\VCOMConfiguration_Controller\" and upload your so file to the folder /c/ni-rt/NIVeriStand/Custom Devices/NI VCOM/ on your RT target. You must ensure that their name are the same.

On Windows:

On Linux RT:

For Windows, don't use the attached dll file. You should generate your own dll file which contains your custom checksum algorithm. 

5. <NIXNETCustomInterface>Path_To_DLL/SO</<NIXNETCustomInterface> is no longer in use. Add the tag <PSPRFMPath>Name_Of_DLL</PSPRFMPath> in the VCOMConfig.xml file. You have to edit the XML file with a Text editing tool. In later VCOM version, it will be possible to define PSPRFMPath from webUI configuration pane or configuration tool in VeriStand.

6. Open the VeriStand System Explorer window, navigate to VCOM->Set VCOM Configuration->Save, then close the configuration file window. The signal tree window will be open as the following.

[PortName].FrameManipulation.TX_enable is created to enable the calculation of checksum for transmission frames. [PortName].FrameManipulation.RX_enable is created to enable the calculation of checksum for receive frames.

7. Deploy the VeriStand System Definition file to the Linux RT. The libTbPSPRFMtest.dll will be detected as an external library path. Don't worry, VCOM will load the so file which has the same name as the dll file.

If you encounter any issues while using the new module, please contact our technical support.

Note: The attached PSPRFM Module_Linux RT zip file is for Linux RT and The PSPRFM Module_Windows zip file is for Windows. You can use it as it is.