Vela Bare-Metal Example Generator

This repo contains:

• a script that converts the raw output provided by Vela into C that directly invokes the Ethos driver
• A proof-of-concept example output for the MLPerf Tiny KWS model
• A snapshot of the ethos driver and a customer toolchain file to compile it for Ambiqsuite-compatible binaries
• A neuralspot-compatible wrapper that gets that compiling

Limitations

• Only single-command-stream models are supported. Any model that requires CPU fallback will fail to convert.
• Only GCC (arm-none-eabi-gcc, specifically) is supported
• This has not been tested on real hardware. We only know that it compiles.

Process

1. Compile the model using Vela
2. Convert the resulting raw output file (a serialized numpy file) into C
3. Compile the resulting C as needed (at minimum you need a main() and a pointer to the Ethos register base)

Compiling your model using Vela

pip install ethos-u-vela
vela --accelerator-config ethos-u85-256 ../clean/model_perf_tests/models/kws/kws_ref_model_aligned.tflite --output-format raw

Converting model to C

python vela_raw_to_c.py ../output/kws_ref_model_aligned_vela.npz --out-dir . --prefix foo

Compiling Ethos Driver

The repo contains contains a pre-built ethos static lib ready for linking into a C project, but if you need to modify something, here is how to compile

$> rm -rf build
$> cmake -B build \\n  -DCMAKE_TOOLCHAIN_FILE=./arm-none-eabi-gcc.cmake \\n  -DTARGET_CPU=cortex-m55 \\n  -DETHOSU_TARGET_NPU_CONFIG=ethos-u85-256 \\n  -DCMSIS_PATH=../../clean/neuralSPOT/extern/CMSIS/CMSIS_5-5.9.0\ncmake --build build -j

Compiling the example

This example is designed to compile in neuralSPOT, but it should be pretty straightforward to compile into bare metal C. To compile the example:

$> cp -R example/vela ../neuralSPOT/apps/experiments
$> cd ../neuralSPOT
$> make EXAMPLE=experiments/vela