Firmware for Thunderboard Sense 2 that collaborates with the corresponding Scratch 3 extension
The basic idea was to make Silicon Labs' Thunderboard Sense 2 usable in Scratch 3 just like micro:bit. First, I tried to find the source of Scratch's firmware for micro:bit however, I was unable to find it - thus I "reverse engineered" it from the Scratch 3 JavaScript extension.
The current implementation mimics Scratch's micro:bit firmware operation. There are two characteristics:
rx: read and notify properties enabled, all values passed to the client in anuint8_tarraytx: write property enabled, starts with a command byte followed by the function-specific data
Currently, LED color (brightness) and LED state (on/off) as control and X/Y acceleration (tilt), temperature and humidity sensor, and two buttons as sensing are supported.
To compile the project Simplicity Studio v5 (with Bluetooth SDK) should be installed. Clone/download the repo and import in Simplicity Studio. Open the .slcp file in the project root (the SDK selector may appear - choose the installed one) then click on Force Generation on the Overview tab before compile. If the compilation went OK burn it to Thunderboard Sense 2 (BRD4166A).
You need to add Scratch 3 Thunderboard Sense 2 extension to Scratch to make the board work in Scratch 3. Note: the release versions must match.
Additionally, you need to run Scratch Link, the WebSocket <-> Bluetooth proxy to access Bluetooth devices from Scratch 3. Since my preference is Linux I used scratch_link.py and not the official Scratch Link.
Note: this project is independent of Silicon Labs and Scratch not officially supported by any of these organizations.