SDS Template Application

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

• Validate and optimize algorithms using playback. This makes it possible to repeat test cases with the same data stream.
• The captured data streams can be labeled and used as a training dataset for AI models in MLOps systems.

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

An SDSIO-Layer connects the SDS template application to a communication interface for SDS file I/O operations. For hardware targets, the following SDSIO interfaces are available as pre-configured software layers:

• 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. Three target types are available, allowing the test application to be deployed either on hardware (an evaluation board) or on one of two AVH FVP simulation models.

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 the Keil Studio.

The example below uses the STM32F746G-DISCO board, which 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 selected evaluation board, for example with:

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

Create New Solution

In the Create a new solution dialog, select the target board and the SDS reference application.

After the csolution project loads, VS Code displays a dialog where you can select a compatible software layer and an installed compiler toolchain.

Build the Template Application

The SDS template application contains three targets (an evaluation board and two AVH FVP simulation models) and two projects:

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

Use the CMSIS:Manage Solution Settings command to select the project you want to explore. Start with DataTest, which should work out of the box on target hardware.

Once the project is selected and the debug adapter is configured, save the solution 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.

  packs:
    - pack: <DFP for your hardware> # use keil.arm.com/packs to search for packs

  target-types:
    - type: MyHardware
      device: STM32U535CBTx
      variables:
        - Board-Layer: $SolutionDir()$/Board/MyHardware/Board.clayer.yml
        - SDSIO-Layer: $SolutionDir()$/sdsio/rtt/sdsio_rtt.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 Hardware Target

1. Select the STM32F746G-DISCO target with Project DataTest and Build Type Debug to record/playback SDS data files.
2. Configure the file datatest.sdsio.yml for your selected communication interface.
3. Start the SDSIO-Server with python sdsio-server.py -c datatest.sdsio.yml.
4. Build and Run the application.
5. Use SDS-Check to verify correctness of the recording.

Recording

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

This run should generate the files Test_In.1.sds and Test_Out.1.sds in the folder datatest/SDS Recordings. The DataTest project is configured to record 1000 data records at an interval of 10 ms.

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

python sds-check.py -i Test_In.1.sds
python sds-check.py -i Test_Out.1.sds

When recording is started again, new files with different names are created: Test_In.2.sds and Test_Out.2.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 in the folder datatest/SDS Recordings. The Test_Out.0.sds file generated during recording is identical to Test_Out.0.p.sds, which is generated in playback mode.

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

python sds-check.py -i 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. In datatest/algorithm_config.h, you can configure bandwidth and interval to match the requirements of the algorithm under test.

Playback on Simulation Model

1. Select the target SSE-300-U55 (or SSE-320-U85) with Project DataTest and Build Type Debug to play back SDS data files.
2. Build and Run the application.
3. Use SDS-Check to verify correctness of the files recorded during playback.

By default, the Template application includes a datatest.sdsio.yml configuration file that specifies playback of the Test_In.0.sds file, while new output recordings are stored in the Test_Out.0.p.sds file.

Refer to SDSIO control file: sdsio.yml for more information and configuration of playback files using the play: node.

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

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

Using AlgorithmTest

The AlgorithmTest project allows you 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 must be modified to integrate the DSP/ML algorithm under test:

• 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 the README.md files included with the example configurations.