mirror of
https://github.com/rtic-rs/rtic.git
synced 2024-11-26 05:29:38 +01:00
345 lines
21 KiB
HTML
345 lines
21 KiB
HTML
<!DOCTYPE HTML>
|
|
<html lang="en" class="light" dir="ltr">
|
|
<head>
|
|
<!-- Book generated using mdBook -->
|
|
<meta charset="UTF-8">
|
|
<title>The app - Real-Time Interrupt-driven Concurrency</title>
|
|
|
|
|
|
<!-- Custom HTML head -->
|
|
|
|
<meta name="description" content="">
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|
<meta name="theme-color" content="#ffffff">
|
|
|
|
<link rel="icon" href="../favicon.svg">
|
|
<link rel="shortcut icon" href="../favicon.png">
|
|
<link rel="stylesheet" href="../css/variables.css">
|
|
<link rel="stylesheet" href="../css/general.css">
|
|
<link rel="stylesheet" href="../css/chrome.css">
|
|
<link rel="stylesheet" href="../css/print.css" media="print">
|
|
|
|
<!-- Fonts -->
|
|
<link rel="stylesheet" href="../FontAwesome/css/font-awesome.css">
|
|
<link rel="stylesheet" href="../fonts/fonts.css">
|
|
|
|
<!-- Highlight.js Stylesheets -->
|
|
<link rel="stylesheet" href="../highlight.css">
|
|
<link rel="stylesheet" href="../tomorrow-night.css">
|
|
<link rel="stylesheet" href="../ayu-highlight.css">
|
|
|
|
<!-- Custom theme stylesheets -->
|
|
|
|
</head>
|
|
<body class="sidebar-visible no-js">
|
|
<div id="body-container">
|
|
<!-- Provide site root to javascript -->
|
|
<script>
|
|
var path_to_root = "../";
|
|
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
|
|
</script>
|
|
|
|
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
|
<script>
|
|
try {
|
|
var theme = localStorage.getItem('mdbook-theme');
|
|
var sidebar = localStorage.getItem('mdbook-sidebar');
|
|
|
|
if (theme.startsWith('"') && theme.endsWith('"')) {
|
|
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
|
}
|
|
|
|
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
|
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
|
}
|
|
} catch (e) { }
|
|
</script>
|
|
|
|
<!-- Set the theme before any content is loaded, prevents flash -->
|
|
<script>
|
|
var theme;
|
|
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
|
if (theme === null || theme === undefined) { theme = default_theme; }
|
|
var html = document.querySelector('html');
|
|
html.classList.remove('light')
|
|
html.classList.add(theme);
|
|
var body = document.querySelector('body');
|
|
body.classList.remove('no-js')
|
|
body.classList.add('js');
|
|
</script>
|
|
|
|
<input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
|
|
|
|
<!-- Hide / unhide sidebar before it is displayed -->
|
|
<script>
|
|
var body = document.querySelector('body');
|
|
var sidebar = null;
|
|
var sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
|
|
if (document.body.clientWidth >= 1080) {
|
|
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
|
sidebar = sidebar || 'visible';
|
|
} else {
|
|
sidebar = 'hidden';
|
|
}
|
|
sidebar_toggle.checked = sidebar === 'visible';
|
|
body.classList.remove('sidebar-visible');
|
|
body.classList.add("sidebar-" + sidebar);
|
|
</script>
|
|
|
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
|
<div class="sidebar-scrollbox">
|
|
<ol class="chapter"><li class="chapter-item expanded affix "><a href="../preface.html">Preface</a></li><li class="chapter-item expanded affix "><li class="spacer"></li><li class="chapter-item expanded "><a href="../starting_a_project.html"><strong aria-hidden="true">1.</strong> Starting a new project</a></li><li class="chapter-item expanded "><a href="../by-example.html"><strong aria-hidden="true">2.</strong> RTIC by example</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../by-example/app.html" class="active"><strong aria-hidden="true">2.1.</strong> The app</a></li><li class="chapter-item expanded "><a href="../by-example/hardware_tasks.html"><strong aria-hidden="true">2.2.</strong> Hardware tasks</a></li><li class="chapter-item expanded "><a href="../by-example/software_tasks.html"><strong aria-hidden="true">2.3.</strong> Software tasks & spawn</a></li><li class="chapter-item expanded "><a href="../by-example/resources.html"><strong aria-hidden="true">2.4.</strong> Resources</a></li><li class="chapter-item expanded "><a href="../by-example/app_init.html"><strong aria-hidden="true">2.5.</strong> The init task</a></li><li class="chapter-item expanded "><a href="../by-example/app_idle.html"><strong aria-hidden="true">2.6.</strong> The idle task</a></li><li class="chapter-item expanded "><a href="../by-example/channel.html"><strong aria-hidden="true">2.7.</strong> Channel based communication</a></li><li class="chapter-item expanded "><a href="../by-example/delay.html"><strong aria-hidden="true">2.8.</strong> Delay and Timeout using Monotonics</a></li><li class="chapter-item expanded "><a href="../by-example/app_minimal.html"><strong aria-hidden="true">2.9.</strong> The minimal app</a></li><li class="chapter-item expanded "><a href="../by-example/tips/index.html"><strong aria-hidden="true">2.10.</strong> Tips & Tricks</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../by-example/tips/destructureing.html"><strong aria-hidden="true">2.10.1.</strong> Resource de-structure-ing</a></li><li class="chapter-item expanded "><a href="../by-example/tips/indirection.html"><strong aria-hidden="true">2.10.2.</strong> Avoid copies when message passing</a></li><li class="chapter-item expanded "><a href="../by-example/tips/static_lifetimes.html"><strong aria-hidden="true">2.10.3.</strong> 'static super-powers</a></li><li class="chapter-item expanded "><a href="../by-example/tips/view_code.html"><strong aria-hidden="true">2.10.4.</strong> Inspecting generated code</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="../monotonic_impl.html"><strong aria-hidden="true">3.</strong> Monotonics & the Timer Queue</a></li><li class="chapter-item expanded "><a href="../rtic_vs.html"><strong aria-hidden="true">4.</strong> RTIC vs. the world</a></li><li class="chapter-item expanded "><a href="../rtic_and_embassy.html"><strong aria-hidden="true">5.</strong> RTIC and Embassy</a></li><li class="chapter-item expanded "><a href="../awesome_rtic.html"><strong aria-hidden="true">6.</strong> Awesome RTIC examples</a></li><li class="chapter-item expanded affix "><li class="spacer"></li><li class="chapter-item expanded "><a href="../migration_v1_v2.html"><strong aria-hidden="true">7.</strong> Migrating from v1.0.x to v2.0.0</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../migration_v1_v2/monotonics.html"><strong aria-hidden="true">7.1.</strong> Migrating to rtic-monotonics</a></li><li class="chapter-item expanded "><a href="../migration_v1_v2/async_tasks.html"><strong aria-hidden="true">7.2.</strong> Software tasks must now be async</a></li><li class="chapter-item expanded "><a href="../migration_v1_v2/rtic-sync.html"><strong aria-hidden="true">7.3.</strong> Using and understanding rtic-sync</a></li><li class="chapter-item expanded "><a href="../migration_v1_v2/complete_example.html"><strong aria-hidden="true">7.4.</strong> A code example on migration</a></li></ol></li><li class="chapter-item expanded "><li class="spacer"></li><li class="chapter-item expanded "><a href="../internals.html"><strong aria-hidden="true">8.</strong> Under the hood</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../internals/targets.html"><strong aria-hidden="true">8.1.</strong> Cortex-M architectures</a></li></ol></li></ol>
|
|
</div>
|
|
<div id="sidebar-resize-handle" class="sidebar-resize-handle">
|
|
<div class="sidebar-resize-indicator"></div>
|
|
</div>
|
|
</nav>
|
|
|
|
<!-- Track and set sidebar scroll position -->
|
|
<script>
|
|
var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox');
|
|
sidebarScrollbox.addEventListener('click', function(e) {
|
|
if (e.target.tagName === 'A') {
|
|
sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop);
|
|
}
|
|
}, { passive: true });
|
|
var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll');
|
|
sessionStorage.removeItem('sidebar-scroll');
|
|
if (sidebarScrollTop) {
|
|
// preserve sidebar scroll position when navigating via links within sidebar
|
|
sidebarScrollbox.scrollTop = sidebarScrollTop;
|
|
} else {
|
|
// scroll sidebar to current active section when navigating via "next/previous chapter" buttons
|
|
var activeSection = document.querySelector('#sidebar .active');
|
|
if (activeSection) {
|
|
activeSection.scrollIntoView({ block: 'center' });
|
|
}
|
|
}
|
|
</script>
|
|
|
|
<div id="page-wrapper" class="page-wrapper">
|
|
|
|
<div class="page">
|
|
<div id="menu-bar-hover-placeholder"></div>
|
|
<div id="menu-bar" class="menu-bar sticky">
|
|
<div class="left-buttons">
|
|
<label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
|
<i class="fa fa-bars"></i>
|
|
</label>
|
|
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
|
<i class="fa fa-paint-brush"></i>
|
|
</button>
|
|
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
|
<li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
|
</ul>
|
|
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
|
<i class="fa fa-search"></i>
|
|
</button>
|
|
</div>
|
|
|
|
<h1 class="menu-title">Real-Time Interrupt-driven Concurrency</h1>
|
|
|
|
<div class="right-buttons">
|
|
<a href="../print.html" title="Print this book" aria-label="Print this book">
|
|
<i id="print-button" class="fa fa-print"></i>
|
|
</a>
|
|
<a href="https://github.com/rtic-rs/rtic" title="Git repository" aria-label="Git repository">
|
|
<i id="git-repository-button" class="fa fa-github"></i>
|
|
</a>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
<div id="search-wrapper" class="hidden">
|
|
<form id="searchbar-outer" class="searchbar-outer">
|
|
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
|
</form>
|
|
<div id="searchresults-outer" class="searchresults-outer hidden">
|
|
<div id="searchresults-header" class="searchresults-header"></div>
|
|
<ul id="searchresults">
|
|
</ul>
|
|
</div>
|
|
</div>
|
|
|
|
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
|
<script>
|
|
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
|
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
|
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
|
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
|
});
|
|
</script>
|
|
|
|
<div id="content" class="content">
|
|
<main>
|
|
<h1 id="the-app-attribute-and-an-rtic-application"><a class="header" href="#the-app-attribute-and-an-rtic-application">The <code>#[app]</code> attribute and an RTIC application</a></h1>
|
|
<h2 id="requirements-on-the-app-attribute"><a class="header" href="#requirements-on-the-app-attribute">Requirements on the <code>app</code> attribute</a></h2>
|
|
<p>All RTIC applications use the <a href="../../../api/rtic_macros/attr.app.html"><code>app</code></a> attribute (<code>#[app(..)]</code>). This attribute only applies to a <code>mod</code>-item containing the RTIC application.</p>
|
|
<p>The <code>app</code> attribute has a mandatory <code>device</code> argument that takes a <em>path</em> as a value. This must be a full path pointing to a <em>peripheral access crate</em> (PAC) generated using <a href="https://crates.io/crates/svd2rust"><code>svd2rust</code></a> <strong>v0.14.x</strong> or newer.</p>
|
|
<p>The <code>app</code> attribute will expand into a suitable entry point and thus replaces the use of the <a href="https://docs.rs/cortex-m-rt-macros/latest/cortex_m_rt_macros/attr.entry.html"><code>cortex_m_rt::entry</code></a> attribute.</p>
|
|
<h2 id="structure-and-zero-cost-concurrency"><a class="header" href="#structure-and-zero-cost-concurrency">Structure and zero-cost concurrency</a></h2>
|
|
<p>An RTIC <code>app</code> is an executable system model for single-core applications, declaring a set of <code>local</code> and <code>shared</code> resources operated on by a set of <code>init</code>, <code>idle</code>, <em>hardware</em> and <em>software</em> tasks.</p>
|
|
<ul>
|
|
<li><code>init</code> runs before any other task, and returns the <code>local</code> and <code>shared</code> resources.</li>
|
|
<li>Tasks (both hardware and software) run preemptively based on their associated static priority.</li>
|
|
<li>Hardware tasks are bound to underlying hardware interrupts.</li>
|
|
<li>Software tasks are schedulied by an set of asynchronous executors, one for each software task priority.</li>
|
|
<li><code>idle</code> has the lowest priority, and can be used for background work, and/or to put the system to sleep until it is woken by some event.</li>
|
|
</ul>
|
|
<p>At compile time the task/resource model is analyzed under the Stack Resource Policy (SRP) and executable code generated with the following outstanding properties:</p>
|
|
<ul>
|
|
<li>Guaranteed race-free resource access and deadlock-free execution on a single-shared stack.</li>
|
|
<li>Hardware task scheduling is performed directly by the hardware.</li>
|
|
<li>Software task scheduling is performed by auto generated async executors tailored to the application.</li>
|
|
</ul>
|
|
<p>Overall, the generated code infers no additional overhead in comparison to a hand-written implementation, thus in Rust terms RTIC offers a zero-cost abstraction to concurrency.</p>
|
|
<h2 id="priority"><a class="header" href="#priority">Priority</a></h2>
|
|
<p>Priorities in RTIC are specified using the <code>priority = N</code> (where N is a positive number) argument passed to the <code>#[task]</code> attribute. All <code>#[task]</code>s can have a priority. If the priority of a task is not specified, it is set to the default value of 0.</p>
|
|
<p>Priorities in RTIC follow a higher value = more important scheme. For examples, a task with priority 2 will preempt a task with priority 1.</p>
|
|
<h2 id="an-rtic-application-example"><a class="header" href="#an-rtic-application-example">An RTIC application example</a></h2>
|
|
<p>To give a taste of RTIC, the following example contains commonly used features.
|
|
In the following sections we will go through each feature in detail.</p>
|
|
<pre><code class="language-rust noplayground">//! examples/common.rs
|
|
|
|
#![no_main]
|
|
#![no_std]
|
|
#![deny(warnings)]
|
|
#![deny(unsafe_code)]
|
|
#![deny(missing_docs)]
|
|
|
|
use panic_semihosting as _;
|
|
|
|
#[rtic::app(device = lm3s6965, dispatchers = [UART0, UART1])]
|
|
mod app {
|
|
use cortex_m_semihosting::{debug, hprintln};
|
|
|
|
#[shared]
|
|
struct Shared {}
|
|
|
|
#[local]
|
|
struct Local {
|
|
local_to_foo: i64,
|
|
local_to_bar: i64,
|
|
local_to_idle: i64,
|
|
}
|
|
|
|
// `#[init]` cannot access locals from the `#[local]` struct as they are initialized here.
|
|
#[init]
|
|
fn init(_: init::Context) -> (Shared, Local) {
|
|
foo::spawn().unwrap();
|
|
bar::spawn().unwrap();
|
|
|
|
(
|
|
Shared {},
|
|
// initial values for the `#[local]` resources
|
|
Local {
|
|
local_to_foo: 0,
|
|
local_to_bar: 0,
|
|
local_to_idle: 0,
|
|
},
|
|
)
|
|
}
|
|
|
|
// `local_to_idle` can only be accessed from this context
|
|
#[idle(local = [local_to_idle])]
|
|
fn idle(cx: idle::Context) -> ! {
|
|
let local_to_idle = cx.local.local_to_idle;
|
|
*local_to_idle += 1;
|
|
|
|
hprintln!("idle: local_to_idle = {}", local_to_idle);
|
|
|
|
debug::exit(debug::EXIT_SUCCESS); // Exit QEMU simulator
|
|
|
|
// error: no `local_to_foo` field in `idle::LocalResources`
|
|
// _cx.local.local_to_foo += 1;
|
|
|
|
// error: no `local_to_bar` field in `idle::LocalResources`
|
|
// _cx.local.local_to_bar += 1;
|
|
|
|
loop {
|
|
cortex_m::asm::nop();
|
|
}
|
|
}
|
|
|
|
// `local_to_foo` can only be accessed from this context
|
|
#[task(local = [local_to_foo], priority = 1)]
|
|
async fn foo(cx: foo::Context) {
|
|
let local_to_foo = cx.local.local_to_foo;
|
|
*local_to_foo += 1;
|
|
|
|
// error: no `local_to_bar` field in `foo::LocalResources`
|
|
// cx.local.local_to_bar += 1;
|
|
|
|
hprintln!("foo: local_to_foo = {}", local_to_foo);
|
|
}
|
|
|
|
// `local_to_bar` can only be accessed from this context
|
|
#[task(local = [local_to_bar], priority = 1)]
|
|
async fn bar(cx: bar::Context) {
|
|
let local_to_bar = cx.local.local_to_bar;
|
|
*local_to_bar += 1;
|
|
|
|
// error: no `local_to_foo` field in `bar::LocalResources`
|
|
// cx.local.local_to_foo += 1;
|
|
|
|
hprintln!("bar: local_to_bar = {}", local_to_bar);
|
|
}
|
|
}</code></pre>
|
|
|
|
</main>
|
|
|
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|
<!-- Mobile navigation buttons -->
|
|
<a rel="prev" href="../by-example.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
<i class="fa fa-angle-left"></i>
|
|
</a>
|
|
|
|
<a rel="next prefetch" href="../by-example/hardware_tasks.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
<i class="fa fa-angle-right"></i>
|
|
</a>
|
|
|
|
<div style="clear: both"></div>
|
|
</nav>
|
|
</div>
|
|
</div>
|
|
|
|
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
|
<a rel="prev" href="../by-example.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
<i class="fa fa-angle-left"></i>
|
|
</a>
|
|
|
|
<a rel="next prefetch" href="../by-example/hardware_tasks.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
<i class="fa fa-angle-right"></i>
|
|
</a>
|
|
</nav>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<script>
|
|
window.playground_copyable = true;
|
|
</script>
|
|
|
|
|
|
<script src="../elasticlunr.min.js"></script>
|
|
<script src="../mark.min.js"></script>
|
|
<script src="../searcher.js"></script>
|
|
|
|
<script src="../clipboard.min.js"></script>
|
|
<script src="../highlight.js"></script>
|
|
<script src="../book.js"></script>
|
|
|
|
<!-- Custom JS scripts -->
|
|
<script src="../mermaid.min.js"></script>
|
|
<script src="../mermaid-init.js"></script>
|
|
|
|
|
|
</div>
|
|
</body>
|
|
</html>
|