SDS Template Application

The SDS template application is a test framework for DSP and ML algorithms. It allows recording and playback of real-world data streams using physical hardware or on simulation models using (Arm Virtual Hardware - FVP) to an user algorithm under test. The real-world data streams are captured in SDS data files. This enables multiple uses cases:

• Validate and Optimize Algorithms using playback. This allows to repeat test cases with the same data streams.
• The captured data streams can be labeled and used as training data set for AI Models in MLOps systems.

The SDS template application is implemented as CMSIS-Toolbox Reference Application. It is hardware agnostic and requires a SDSIO-Layer and a Board-Layer with drivers for the specific target hardware.

The SDSIO-Layer connects the SDS template application to a communication interface for SDS file I/O operations. The following SDSIO interfaces are pre-configured:

• Ethernet Interface using the MDK-Middleware Network component.
• USB Bulk Interface using the MDK-Middleware USB component.
• RTT (Real-Time Transfer) using the SEGGER RTT component for I/O via the debug adapter.
• Memory Card Interface using the MDK-Middleware File System component. With a custom SDSIO interface, alternative I/O configurations are possible.

SDS Template Structure

The structure of the SDS template application is shown below. Two projects let you choose between a data communication test and a user algorithm test. Two target types let you deploy the test application either on hardware (evaluation board) or on an AVH FVP (simulation model).

A standard board layer, provided by several BSPs, implements the hardware interface. For communication, the SDSIO layer uses the MDK-Middleware or (for the AVH FVP target) a virtual simulation interface (VSI).

The Debug and Release build types differ only in the optimization level and the amount of debug information printed. Both build types support recording and playback, controlled via sdsFlags. The sdsFlags value can be modified by the SDS application (using the function sdsFlagsModify) or by the SDSIO-Server, making it easy to switch between Record Mode and Playback Mode.

Record Mode

Record mode captures the input data stream and the algorithm output data stream simultaneously.

Playback Mode

Playback mode replays the input data stream while recording the algorithm output data stream at the same time. The test application can run either on hardware (evaluation board) or on an AVH FVP (simulation model). Because the input data stream can be repeated, it enables consistent verification and optimization of the algorithm while capturing the resulting output data stream.

Working with the SDS Template

The SDS template application and SDSIO interface layers are part of the SDS pack.

Several Board Support Packs (BSP) contain board layers that support the required API interfaces. Refer to the Overview page of the pack to check the Provided connection API Interface of the layers. The table below lists the required API interfaces that should be provided by the Board-Layer.

Required API Interface	Description
SDSIO File System
CMSIS_MCI	CMSIS-Driver MCI interface to memory card.
CMSIS_VIO, STDOUT, STDERR	For user button and printf output.
SDSIO Network
CMSIS_ETH	CMSIS-Driver Ethernet MAC/PHY interface.
CMSIS_VIO, STDOUT, STDERR	For user button and printf output.
SDSIO USB Device
CMSIS_USB_Device	CMSIS-Driver USB Device interface.
CMSIS_VIO, STDOUT, STDERR	For user button and printf output.

Using VS Code

This section explains how to use SDS template application with the Arm CMSIS Solution for VS Code. This extension is for example part of Keil Studio.

For the example below the STM32F746G-DISCO board is used that provides interfaces for all SDSIO communication interfaces.

Install Required Packs

To make the software components available, install the SDS pack and the pack for the select evaluation board, for example with:

>cpackget add ARM::SDS
>cpackget add Keil::STM32F746G-DISCO_BSP

Create New Solution

The SDS template application is selected in the Create a new solution dialog for boards with layers in the BSP.

Once the csolution project is loaded the VS Code IDE presents you with a dialog that lets you select a compatible software layer and a compiler toolchain that is available on your computer.

Build the Template Application

The SDS template applications contains two targets (evaluation board, AVH FVP simulation model) and two projects:

• DataTest is a data communication test between target and SDSIO Server or file system.
• AlgorithmTest allows to add the DSP or ML algorithm that should be tested.

Use the command CMSIS:Manage Solution Settings to choose a one project that you want to explore. Start with the DataTest first that should work "out-of-the box" on target hardware.

Once the configuration is selected, click Save and use the build command to generate the template application. Then download the application to the selected target.

Compile for Custom Hardware

The steps to add a custom hardware configuration are:

• Open the *.csolution.yml file and add a new target-type.

    target-types:
    - type: MyHardware
      device: STM32U535CBTx
      variables:
        - Board-Layer: $SolutionDir()$\Board\MyHardware\Board.clayer.yml
        - SDSIO-Layer: $SolutionDir()$\layer\usb\sdsio_usb.clayer.yml

• Add a board layer that implements the API interfaces described above.

Using DataTest

The DataTest project validates the communication channel.

Recording/playback on Simulation Model

1. Select the target AVH-SSE-300 (or AVH-SSE-320) with Project DataTest and Build Type Debug to record/playback SDS data files.
2. Start the SDSIO Server for selected SDSIO communication interface.
3. Build and Run the application.
4. Use SDS-Check to verify correctness of the recording.

Recording

Activate the recording from the SDSIO Server by pressing R key. To stop the recording press the S key.

This run should generate the files Test_In.0.sds and Test_Out.0.sds in the solution folder. The DataTest project is configured to record 1000 data records at an interval of 10 ms.

To verify correctness of the recording using SDS-Check utility use the following commands:

python sds-check.py -s Test_In.0.sds
python sds-check.py -s Test_Out.0.sds

When the project is restarted, new files with different names are created: Test_In.1.sds and Test_Out.1.sds.

Playback

Activate the playback from the SDSIO Server by pressing the P key.

This run should read the Test_In.0.sds file and generate the Test_Out.0.p.sds file.

To verify correctness of the recording using SDS-Check utility use the following command:

python sds-check.py -s Test_Out.0.p.sds

Compare the output files Test_Out.0.sds and Test_Out.0.p.sds with any program that can compare binary files. If the communication is correct, the files should be identical.

Recording/playback on Hardware Target

1. Select the STM32F746G-DISCO target with Project DataTest and Build Type Debug to record/playback SDS data files.
2. Start the SDSIO Server for selected SDSIO communication interface.
3. Build and Run the application.
4. Use SDS-Check to verify correctness of the recording.

Recording

Activate the recording from the SDSIO Server by pressing R key. To stop the recording press the S key. Alternatively the recording can be started or stopped by pressing the user button on the board.

This run should generate the files Test_In.0.sds and Test_Out.0.sds in the solution folder. The DataTest project is configured to record 1000 data records at an interval of 10 ms.

To verify correctness of the recording using SDS-Check utility use the following commands:

python sds-check.py -s Test_In.0.sds
python sds-check.py -s Test_Out.0.sds

When the project is restarted, new files with different names are created: Test_In.1.sds and Test_Out.1.sds.

Playback

Activate the playback from the SDSIO Server by pressing the P key.

This run should read the Test_In.0.sds file and generate the Test_Out.0.p.sds file.

To verify correctness of the recording using SDS-Check utility use the following command:

python sds-check.py -s Test_Out.0.p.sds

Compare the output files Test_Out.0.sds and Test_Out.0.p.sds with any program that can compare binary files. If the communication is correct, the files should be identical.

Configure Bandwidth for DataTest

The DataTest project uses a fixed algorithm to verify the communication interface. With the file datatest/algorithm_config.h it is possible to configure bandwidth and interval to match the requirements of the algorithm that should be tested.

Using AlgorithmTest

The project AlgorithmTest allows to add custom algorithms for testing. It is prepared for recording and playback of SDS data files.

Add User Algorithm

In the SDS template application these files require changes to interface with the DSP and ML algorithm that is tested:

• algorithm/algorithm_config.h configures the block size of data streams.
• algorithm/algorithm_user.c is the interface to the DSP/ML algorithm under test.
• algorithm/data_in_user.c is the interface to the physical data source.

Example Projects

Configured variants of the SDS template application are provided in a separate GitHub repository github.com/Arm-Examples/sds-examples. These examples show the usage of the SDS-Framework with real-world devices and use cases.

For details refer to README.md files that are included with the example configurations.