1 unstable release
|0.2.0||Nov 26, 2018|
#5 in #embedded-hal-impl
2 downloads per month
This crate contains wrappers around the RIOT Operating System's C API exposed by riot-sys and makes an attempt to provide idiomatic Rust wrappers (eg. implementing embedded-hal for peripherals, implementing fmt::Write for stdio) around those.
The crate documentation outlines which modules are available, and which other crates' traits they implement.
For practical use and an introduction, see the examples.
The riot-wrappers crate tries to stay out of the way by default to enable various types of applications (ie. not only "Rust application running atop RIOT", but also "RIOT module / driver implemented in Rust" or others).
To facilitate what is currently the best explored use case ("Rust application
running atop RIOT"), applications can use the
main! macro to wrap a regular
Rust function like
fn main() -> () into a function that's exported with
proper name and signature to serve as
main function in RIOT.
When that is used, it also makes sense to enable the
feature. It implements a panic handler that outputs the panic message to RIOT's
standard output, and puts the affected thread to sleep permanently. (There is
no unwinding or similar; threads in RIOT are not really expected to terminate
and be restarted).
With such a main function and panic handler, a Rust crate can be built as a static library and linked as a part of the RIOT build process without the need for application specific C code.
See the riot-examples repository for complete setup examples.
This module uses a
RIOT_CFLAGS environment variable as does riot-sys,
and decides from it which modules to enable: If
MODULE_SAUL is not set, the
saul module will not be built in. This is achieved by parsing the
-DMODULE_... flags of the environment variable.
This makes things very auto-magical, and I'm not yet sure whether that's the best way for things to be. The Cargo way would be that the crate using riot-wrappers actively enables some features in riot-wrappers, which then pulls in features in riot-sys -- but riot-sys can't enable RIOT modules any more as RIOT is already configured. The RIOT way would be to enable the modules the application needs in the Makefile (possibly with dependencies pulling others in), but the crate not being a module makes that hard.
This automagic way is convenient now; later iterations might be more explicit and profit from better integration.
This crate is licensed under the same terms as of the LGPL 2.1, following the license terms of the RIOT Operating System.