rtic/stable/book/en/by-example.html
2024-10-24 05:57:30 +00:00

309 lines
20 KiB
HTML
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE HTML>
<html lang="en" class="light" dir="ltr">
<head>
<!-- Book generated using mdBook -->
<meta charset="UTF-8">
<title>RTIC by example - 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" class="active"><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"><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="rtic-by-example"><a class="header" href="#rtic-by-example">RTIC by example</a></h1>
<p>This part of the book introduces the RTIC framework to new users by walking them through examples of increasing complexity.</p>
<p>All examples in this part of the book are part of the
<a href="https://github.com/rtic-rs/rtic/tree/master/rtic/examples">RTIC repository</a>, found in the <code>examples</code> directory.
The examples are runnable on QEMU (emulating a Cortex M3 target),
thus no special hardware required to follow along.</p>
<h2 id="running-an-example"><a class="header" href="#running-an-example">Running an example</a></h2>
<p>To run the examples with QEMU you will need the <code>qemu-system-arm</code> program.
Check <a href="https://rust-embedded.github.io/book/intro/install.html">the embedded Rust book</a> for instructions on how to set up an
embedded development environment that includes QEMU.</p>
<p>To run the examples found in <code>examples/</code> locally using QEMU:</p>
<pre><code>cargo xtask qemu
</code></pre>
<p>This runs all of the examples against the default <code>thumbv7m-none-eabi</code> device <code>lm3s6965</code>.</p>
<p>To limit which examples are being run, use the flag <code>--example &lt;example name&gt;</code>, the name being the filename of the example.</p>
<p>Assuming dependencies in place, running:</p>
<pre><code class="language-console">$ cargo xtask qemu --example locals
</code></pre>
<p>Yields this output:</p>
<pre><code class="language-console"> Finished dev [unoptimized + debuginfo] target(s) in 0.07s
Running `target/debug/xtask qemu --example locals`
INFO xtask &gt; Testing for platform: Lm3s6965, backend: Thumbv7
INFO xtask::run &gt; 👟 Build example locals (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
INFO xtask::run &gt; ✅ Success.
INFO xtask::run &gt; 👟 Run example locals in QEMU (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
INFO xtask::run &gt; ✅ Success.
INFO xtask::results &gt; ✅ Success: Build example locals (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
INFO xtask::results &gt; ✅ Success: Run example locals in QEMU (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
INFO xtask::results &gt; 🚀🚀🚀 All tasks succeeded 🚀🚀🚀
</code></pre>
<p>It is great that examples are passing and this is part of the RTIC CI setup too, but for the purposes of this book we must add the <code>--verbose</code> flag, or <code>-v</code> for short to see the actual program output:</p>
<pre><code class="language-console"> cargo xtask qemu --verbose --example locals
Finished dev [unoptimized + debuginfo] target(s) in 0.03s
Running `target/debug/xtask qemu --example locals --verbose`
DEBUG xtask &gt; Stderr of child processes is inherited: false
DEBUG xtask &gt; Partial features: false
INFO xtask &gt; Testing for platform: Lm3s6965, backend: Thumbv7
INFO xtask::run &gt; 👟 Build example locals (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
INFO xtask::run &gt; ✅ Success.
INFO xtask::run &gt; 👟 Run example locals in QEMU (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
INFO xtask::run &gt; ✅ Success.
INFO xtask::results &gt; ✅ Success: Build example locals (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
cd examples/lm3s6965 &amp;&amp; cargo build --target thumbv7m-none-eabi --features test-critical-section,thumbv7-backend --release --example locals
DEBUG xtask::results &gt;
cd examples/lm3s6965 &amp;&amp; cargo build --target thumbv7m-none-eabi --features test-critical-section,thumbv7-backend --release --example locals
Stderr:
Finished release [optimized] target(s) in 0.02s
INFO xtask::results &gt; ✅ Success: Run example locals in QEMU (thumbv7m-none-eabi, release, "test-critical-section,thumbv7-backend", in examples/lm3s6965)
cd examples/lm3s6965 &amp;&amp; cargo run --target thumbv7m-none-eabi --features test-critical-section,thumbv7-backend --release --example locals
DEBUG xtask::results &gt;
cd examples/lm3s6965 &amp;&amp; cargo run --target thumbv7m-none-eabi --features test-critical-section,thumbv7-backend --release --example locals
Stdout:
bar: local_to_bar = 1
foo: local_to_foo = 1
idle: local_to_idle = 1
Stderr:
Finished release [optimized] target(s) in 0.02s
Running `qemu-system-arm -cpu cortex-m3 -machine lm3s6965evb -nographic -semihosting-config enable=on,target=native -kernel target/thumbv7m-none-eabi/release/examples/locals`
Timer with period zero, disabling
INFO xtask::results &gt; 🚀🚀🚀 All tasks succeeded 🚀🚀🚀
</code></pre>
<p>Look for the content following <code>Stdout:</code> towards the end ouf the output, the program output should have these lines:</p>
<pre><code class="language-console">bar: local_to_bar = 1
foo: local_to_foo = 1
idle: local_to_idle = 1
</code></pre>
<blockquote>
<p><strong>NOTE</strong>:
For other useful options to <code>cargo xtask</code>, see:</p>
<pre><code>cargo xtask qemu --help
</code></pre>
<p>The <code>--platform</code> flag allows changing which device examples are run on,
currently <code>lm3s6965</code> is the best supported, work is ongoing to
increase support for other devices, including both ARM and RISC-V</p>
</blockquote>
</main>
<nav class="nav-wrapper" aria-label="Page navigation">
<!-- Mobile navigation buttons -->
<a rel="prev" href="starting_a_project.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/app.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="starting_a_project.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/app.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>