Lightbulb Moment

This project is a Topo template and follows the Topo Template Format Specification.

An Arm Cortex-M core reads a physical switch over GPIO and reports its state to a Cortex-A core via RPMsg. A web application on the Cortex-A core displays a lightbulb - on or off - described by an LLM in any user-specified style.

Requirements

• Either an STM32MP257 or i.MX93 board running Linux, with SSH root access and Docker installed.
• ~15GB free disk space on the build machine (the Zephyr build image alone is over 5GB).
• Before deploying to your board, you must ensure the board is set up (see below).

STM32MP257 setup

Depending on the Linux image your board is running, you may need to stop a pre-existing demo program running on the Cortex-M core. You can ensure both cores are stopped using this SSH command:

ssh root@<target hostname> 'echo stop > /sys/class/remoteproc/remoteproc1/state; echo stop > /sys/class/remoteproc/remoteproc0/state'

Note: if nothing is currently running on the cores, you will see "Invalid argument" errors — this is safe to ignore.

i.MX93 setup

The i.MX93 board requires a one-time U-Boot configuration to prepare the Cortex-M core for remoteproc. Without this, the board's remoteproc drivers may not start correctly. Run prepare_mcore in the U-Boot menu before first use — see the setup guide for details.

Usage

The easiest way to deploy is using topo. Install it by following the instructions at github.com/arm/topo.

In the commands below, <user@hostname> refers to the SSH address of your STM32MP257 or i.MX93 board.

Check the target's health using topo

Check the target's health and fix any issues if necessary:

topo health --target <user@hostname>

If remoteproc-runtime is unavailable, you can install it following these instructions

Install remoteproc-runtime on the target using topo

Topo uses remoteproc-runtime to deploy containers to remote processors. If it is not already installed, you can install it using topo:

topo install remoteproc-runtime --target <user@hostname>

Clone the project using topo

The clone step will ask you for the following build arguments:

• PLATFORM: either stm32mp257 or imx93
• REMOTEPROC: either m33 (for stm32mp257) or imx-rproc (for imx93)
• LLM_PROMPT_PRESET: any style description (e.g., "pirate", "shakespearean english", "haiku", "detective noir")

Clone and set arguments:

topo clone git@github.com:Arm-Examples/topo-lightbulb-moment.git

Build and deploy the project

Note: the first build will download the Zephyr toolchain Docker image and other dependencies (~15GB total), so it may take a while.

cd topo-lightbulb-moment
topo deploy --target <user@hostname>