blob: 5bf6200e1c7df58023d670ea7409cb2b245f47ce (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
# App initialization and the `#[init]` task
An RTIC application requires an `init` task setting up the system. The corresponding `init` function must have the
signature `fn(init::Context) -> (Shared, Local, init::Monotonics)`, where `Shared` and `Local` are resource
structures defined by the user.
The `init` task executes after system reset, [after an optionally defined `pre-init` code section][pre-init] and an always occurring internal RTIC
initialization.
[pre-init]: https://docs.rs/cortex-m-rt/latest/cortex_m_rt/attr.pre_init.html
The `init` and optional `pre-init` tasks runs *with interrupts disabled* and have exclusive access to Cortex-M (the
`bare_metal::CriticalSection` token is available as `cs`).
Device specific peripherals are available through the `core` and `device` fields of `init::Context`.
## Example
The example below shows the types of the `core`, `device` and `cs` fields, and showcases the use of a `local`
variable with `'static` lifetime.
Such variables can be delegated from the `init` task to other tasks of the RTIC application.
The `device` field is only available when the `peripherals` argument is set to the default value `true`.
In the rare case you want to implement an ultra-slim application you can explicitly set `peripherals` to `false`.
``` rust
{{#include ../../../../examples/init.rs}}
```
Running the example will print `init` to the console and then exit the QEMU process.
``` console
$ cargo run --target thumbv7m-none-eabi --example init
{{#include ../../../../ci/expected/init.run}}
```
|
