Experimental example a Crazyflie app in Rust.
This prints a hello message on the Crazyflie console and then sleeps forever. Integration with the Crazyflie and FreeRTOS API is non-existent at the moment, this is only a starting point.
Since this app includes the Crazyflie firmware as a subrepos it needs to be cloned with git clone --recursive.
It is also possible to run git submodule update --init --recursive in an already cloned folder to make sure everything is cloned.
The prerequisite to build the rust app is to have a recent rust compiler (tested with 1.51) and the target for the Crazyflie CPU. To install the target with rustup:
rustup target add thumbv7em-none-eabihf
Then, the classic make && make cload will build and flash the firmware together with the app:
make
make cload
The Crazyflie build system allows to add objects to be linked with the Crazyflie.
The Rust project is setup to generate a C static library.
The Makefile calls cargo build to build the lib and adds it to the list of objects to be linked in the Crazyflie firmware.
The Crazyflie firmware will call appMain() at startup.
This function is declared in rust as pub extern "C" to be callable from C.
The FreeRTOS delay function and Crazyflie console putchar function are manually declared extern "C" which allows Rust to call them.
Future improvement includes using a FreeRTOS binding and possibly making a Crazflie binding so that Rust app can do useful things.