CMSIS Ethos-U integration example

This repository demonstrates a CMSIS-Toolbox application using TensorFlow Lite Micro and the Arm Ethos-U NPU on the Alif AppKit-E8-AIML board. It provides Ethos-U55 and Ethos-U85 configurations for the board's M55 high-performance core. The test runs two Vela-compiled LiteRT models, hello_world and tiny_cnn, and compares their outputs with embedded reference values. A successful run prints TEST RESULT: PASS over the board's virtual COM port.

Quick start in VS Code

1. Install Keil Studio for VS Code. Clone this repository and open its root folder in VS Code. Use Arm Tools: Activate Environment if prompted; Arm Tools Environment Manager installs the compiler, CMSIS-Toolbox, and build tools listed in vcpkg-configuration.json. Activate an Arm Compiler license if you choose AC6; GCC is also supported.

2. Prepare the AppKit-E8 board as described in the board layer README. The device needs its ATOC and debug stubs programmed with Alif SETOOLS before this example can run. Use the SE position of SW4 for SETOOLS, then set SW4 to U4 for UART4 test output through the PRG USB connector (J3).

3. Open the CMSIS view and select Open Solution in Workspace. Choose Test-Ethos-U85.csolution.yml, then select the AppKit-E8-U85 target, its J-Link target set, and the Debug build. Use the CMSIS Build action; the extension installs any missing public software packs. The supplied models target Ethos-U85 with 256 MACs and shared SRAM, so this is the starting configuration.

4. Use the CMSIS Load and Run or Load and Debug action with the board's J-Link connection. Open the board's UART4 virtual COM port to view the output. A successful test ends with 2 of 2 checks passed and TEST RESULT: PASS.

For Ethos-U55, open Test-Ethos-U55.csolution.yml and select AppKit-E8-U55. Recompile the models for U55 before running them; see the model converter guide and the configuration table below.

The solutions also include SSE-300-U55 and SSE-320-U85 targets for Corstone FVPs. Their board layers are in Board/Corstone-300/ and Board/Corstone-320/.

Command-line build

With the tools on PATH and the required packs available, build the U85 AppKit-E8 application with:

cbuild Test-Ethos-U85.csolution.yml --active AppKit-E8-U85@J-Link --toolchain GCC --packs

--packs downloads missing public packs. For a different target or compiler, select it with --active or --toolchain respectively. The Build workflow checks the U55 and U85 solutions with both AC6 and GCC.

Project layout

Path	Purpose
Test-Ethos-U55.csolution.yml, Test-Ethos-U85.csolution.yml	Target, build, and MLOps settings for each NPU
Test-Ethos-U.cproject.yml	Shared test application and layer selection
Board/AppKit-E8_M55_HP/	AppKit-E8 board layers, linker configuration, and board setup guide
Model/	Quantized and Vela-compiled models, model sources, and the ML layer
Source/test_main.cpp	Runs both models and checks their outputs
script/	Model converter and its usage guide

The checked-in Vela outputs are ready to build. After changing an NPU or memory configuration, generate the solution's *.cbuild-mlops.yml by opening or building that solution, then recompile the models as described below and in the model converter guide.

Project Configurations for AppKit-E8-AIML

Each column describes one combination of NPU and Vela memory mode.

Setting	U55: SRAM only	U55: shared SRAM	U85: SRAM only	U85: shared SRAM	U85: dedicated SRAM
Solution	Test-Ethos-U55	Test-Ethos-U55	Test-Ethos-U85	Test-Ethos-U85	Test-Ethos-U85
Vela system	RTSS_HP_SRAM_Only	RTSS_HP_SRAM_MRAM	Ethos_U85_SRAM_Only	Ethos_U85_SRAM_MRAM	Ethos_U85_SRAM_SRAM
Vela memory	Sram_Only	Shared_Sram	Sram_Only	Shared_Sram	Dedicated_Sram
NPU_QCONFIG	1	2	1	2	1
NPU_REGIONCFG_0	1	3	1	3	1
NPU_REGIONCFG_1	0	0	0	0	0
NPU_REGIONCFG_2	Unused	Unused	Unused	Unused	1
ETHOS_CACHE_SIZE	Not used	Not used	Not used	Not used	393216 bytes
ethos_model	SRAM via AXI0	MRAM via AXI1	SRAM via AXI_SRAM	MRAM via AXI_EXT	SRAM1 via AXI_SRAM
ethos_arena	SRAM via AXI0	SRAM via AXI0	SRAM via AXI_SRAM	SRAM via AXI_SRAM	SRAM1 via AXI_SRAM
ethos_cache	Unused	Unused	Unused	Unused	SRAM0 via AXI_SRAM
SRAM0_SRAM1_COMBINED	1	1	1	1	0

Set npu.type to Ethos-U55 or Ethos-U85 as indicated by the column, and set npu.macs to 256. Use the table's system and memory values for vela in the corresponding solution. After changing these settings, recompile both hello_world and tiny_cnn:

NPU	Conversion command
U55	python script/model-converter.py Test-Ethos-U55.cbuild-mlops.yml
U85	python script/model-converter.py Test-Ethos-U85.cbuild-mlops.yml

NOTES

• SRAM0_SRAM1_COMBINED is set in app_mem_regions.h
• Vela system names correspond to System_Config.<system> sections in .cmsis/ensemble_vela.ini.
• U85: dedicated SRAM configuration requires ETHOS_CACHE_SIZE to match the Vela arena_cache_size of 393216 bytes.