Michael Stapelberg
387 lines
36 KiB
HTML
387 lines
36 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en-us" dir="ltr" itemscope itemtype="http://schema.org/Article" data-r-output-format="html">
|
||
<head>
|
||
<meta charset="utf-8">
|
||
<meta name="viewport" content="height=device-height, width=device-width, initial-scale=1.0, minimum-scale=1.0">
|
||
<meta name="generator" content="Hugo 0.161.1">
|
||
<meta name="generator" content="Relearn 8.2.0+220806ce3ced8264fbdd693f77f28216a8a1b6ae">
|
||
<meta name="description" content="In this guide, we are using periph.io, a library for peripheral I/O in Go, to set one of the Raspberry Pi’s General Purpose I/O (GPIO) pins to a logical high (3.3V) or low (0V) signal.
|
||
periph.io supports the Raspberry Pi 3, Raspberry Pi Zero 2W and Raspberry Pi 4, starting with version v3.6.4.
|
||
Connect GPIO pins based on pinout To verify the code is doing what we expect, let’s connect a multimeter as per pinout.xyz’s pinout:">
|
||
<meta name="author" content="">
|
||
<meta name="twitter:card" content="summary">
|
||
<meta name="twitter:title" content="Controlling a GPIO input/output pin :: gokrazy">
|
||
<meta name="twitter:description" content="In this guide, we are using periph.io, a library for peripheral I/O in Go, to set one of the Raspberry Pi’s General Purpose I/O (GPIO) pins to a logical high (3.3V) or low (0V) signal.
|
||
periph.io supports the Raspberry Pi 3, Raspberry Pi Zero 2W and Raspberry Pi 4, starting with version v3.6.4.
|
||
Connect GPIO pins based on pinout To verify the code is doing what we expect, let’s connect a multimeter as per pinout.xyz’s pinout:">
|
||
<meta property="og:url" content="https://gokrazy.org/development/gpio/index.html">
|
||
<meta property="og:site_name" content="gokrazy">
|
||
<meta property="og:title" content="Controlling a GPIO input/output pin :: gokrazy">
|
||
<meta property="og:description" content="In this guide, we are using periph.io, a library for peripheral I/O in Go, to set one of the Raspberry Pi’s General Purpose I/O (GPIO) pins to a logical high (3.3V) or low (0V) signal.
|
||
periph.io supports the Raspberry Pi 3, Raspberry Pi Zero 2W and Raspberry Pi 4, starting with version v3.6.4.
|
||
Connect GPIO pins based on pinout To verify the code is doing what we expect, let’s connect a multimeter as per pinout.xyz’s pinout:">
|
||
<meta property="og:locale" content="en_us">
|
||
<meta property="og:type" content="article">
|
||
<meta property="article:section" content="Package development">
|
||
<meta itemprop="name" content="Controlling a GPIO input/output pin :: gokrazy">
|
||
<meta itemprop="description" content="In this guide, we are using periph.io, a library for peripheral I/O in Go, to set one of the Raspberry Pi’s General Purpose I/O (GPIO) pins to a logical high (3.3V) or low (0V) signal.
|
||
periph.io supports the Raspberry Pi 3, Raspberry Pi Zero 2W and Raspberry Pi 4, starting with version v3.6.4.
|
||
Connect GPIO pins based on pinout To verify the code is doing what we expect, let’s connect a multimeter as per pinout.xyz’s pinout:">
|
||
<meta itemprop="wordCount" content="640">
|
||
<title>Controlling a GPIO input/output pin :: gokrazy</title>
|
||
<link href="/images/favicon.png?1782408721" rel="icon" type="image/png">
|
||
<link href="/css/auto-complete/auto-complete.min.css?1782408721" rel="stylesheet">
|
||
<script src="/js/auto-complete/auto-complete.min.js?1782408721" defer></script>
|
||
<script src="/js/search-lunr.min.js?1782408721" defer></script>
|
||
<script src="/js/search.min.js?1782408721" defer></script>
|
||
<script>
|
||
window.relearn = window.relearn || {};
|
||
window.relearn.index_js_url="/searchindex.en.js?1782408721";
|
||
</script>
|
||
<script src="/js/lunr/lunr.min.js?1782408721" defer></script>
|
||
<script src="/js/lunr/lunr.stemmer.support.min.js?1782408721" defer></script>
|
||
<script src="/js/lunr/lunr.multi.min.js?1782408721" defer></script>
|
||
<script src="/js/lunr/lunr.en.min.js?1782408721" defer></script>
|
||
<script>
|
||
window.relearn = window.relearn || {};
|
||
window.relearn.contentLangs=['en'];
|
||
</script>
|
||
<link href="/fonts/fontawesome/css/fontawesome-all.min.css?1782408721" rel="stylesheet" media="print" onload="this.media='all';this.onload=null;"><noscript><link href="/fonts/fontawesome/css/fontawesome-all.min.css?1782408721" rel="stylesheet"></noscript>
|
||
<link href="/css/perfect-scrollbar/perfect-scrollbar.min.css?1782408721" rel="stylesheet">
|
||
<link href="/css/theme.min.css?1782408721" rel="stylesheet">
|
||
<link href="/css/format-html.min.css?1782408721" rel="stylesheet" id="R-format-style">
|
||
<script>
|
||
window.relearn = window.relearn || {};
|
||
// configuration
|
||
window.relearn.min = `.min`;
|
||
window.relearn.path='\/development\/gpio\/index.html';
|
||
window.relearn.relBasePath='..\/..';
|
||
window.relearn.relBaseUri='..\/..';
|
||
window.relearn.absBaseUri='https:\/\/gokrazy.org';
|
||
window.relearn.disableInlineCopyToClipboard=true;
|
||
window.relearn.enableBlockCodeWrap=true;
|
||
// legal
|
||
window.relearn.getItem = (s,n) => {return s.getItem(n)};
|
||
window.relearn.setItem = (s,n,v) => {return s.setItem(n,v)};
|
||
window.relearn.removeItem = (s,n) => {return s.removeItem(n)};
|
||
// translations
|
||
window.T_Copy_to_clipboard = `Copy text to clipboard`;
|
||
window.T_Copied_to_clipboard = `Text copied to clipboard!`;
|
||
window.T_Link_copied_to_clipboard = `Link copied to clipboard!`;
|
||
window.T_Reset_view = `Reset view`;
|
||
window.T_View_reset = `View reset!`;
|
||
window.T_No_results_found = `No results found for "{0}"`;
|
||
window.T_N_results_found = `{1} results found for "{0}"`;
|
||
window.T_Browser_unsupported_feature = `This browser doesn't support this feature`;
|
||
// variant stuff
|
||
window.relearn.themevariants = [ 'auto' ];
|
||
window.relearn.customvariantname = "my-custom-variant";
|
||
window.relearn.changeVariant = function(variant) {
|
||
var oldVariant = document.documentElement.dataset.rThemeVariant;
|
||
window.relearn.setItem(window.localStorage, window.relearn.absBaseUri + "/variant", variant);
|
||
document.documentElement.dataset.rThemeVariant = variant;
|
||
if (oldVariant != variant) {
|
||
document.dispatchEvent( new CustomEvent('themeVariantLoaded', { detail: { variant, oldVariant } }) );
|
||
window.relearn.markVariant();
|
||
}
|
||
}
|
||
window.relearn.markVariant = function() {
|
||
var variant = window.relearn.getItem(window.localStorage, window.relearn.absBaseUri + "/variant");
|
||
document.querySelectorAll(".R-variantswitcher select").forEach((select) => {select.value = variant;});
|
||
}
|
||
window.relearn.initVariant = function() {
|
||
var variant = window.relearn.getItem(window.localStorage, window.relearn.absBaseUri + "/variant") ?? "";
|
||
if( variant == window.relearn.customvariantname ){
|
||
}else if( !variant || !window.relearn.themevariants.includes(variant) ){
|
||
variant = window.relearn.themevariants[0];
|
||
window.relearn.setItem(window.localStorage, window.relearn.absBaseUri + "/variant", variant);
|
||
}
|
||
document.documentElement.dataset.rThemeVariant = variant;
|
||
}
|
||
window.relearn.initVariant();
|
||
window.relearn.markVariant();
|
||
</script>
|
||
</head>
|
||
<body class="mobile-support html" data-url="/development/gpio/index.html">
|
||
<div id="R-body" class="default-animation">
|
||
<div id="R-body-overlay"></div>
|
||
<nav id="R-topbar">
|
||
<div class="topbar-wrapper">
|
||
<div class="topbar-sidebar-divider"></div>
|
||
<div class="topbar-area topbar-area-start" data-area="start">
|
||
<div class="topbar-button topbar-button-sidebar" data-content-empty="disable" data-width-s="show" data-width-m="hide" data-width-l="hide">
|
||
<span class="btn cstyle button link noborder notitle interactive"><button onclick="toggleNav()" type="button" title="Menu (CTRL+ALT+n)"><i class="fa-fw fas fa-bars"></i></button></span>
|
||
</div>
|
||
<div class="topbar-button topbar-button-toc" data-content-empty="hide" data-width-s="show" data-width-m="show" data-width-l="show">
|
||
<span class="btn cstyle button link noborder notitle interactive"><button onclick="toggleTopbarFlyout(this)" type="button" title="Table of Contents (CTRL+ALT+t)"><i class="fa-fw fas fa-list-alt"></i></button></span>
|
||
<div class="topbar-content">
|
||
<div class="topbar-content-wrapper">
|
||
<nav class="TableOfContents">
|
||
<ul>
|
||
<li><a href="#connect-gpio-pins-based-on-pinout">Connect GPIO pins based on pinout</a></li>
|
||
<li><a href="#setting-an-output-pin-signal">Setting an output pin signal</a></li>
|
||
<li><a href="#setting-up-an-input-pin">Setting up an input pin</a></li>
|
||
</ul>
|
||
</nav>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<ol class="topbar-breadcrumbs breadcrumbs highlightable" itemscope itemtype="http://schema.org/BreadcrumbList"><li itemscope itemtype="https://schema.org/ListItem" itemprop="itemListElement" class=""><a itemprop="item" href="/index.html"><span itemprop="name">gokrazy Go appliances</span></a><meta itemprop="position" content="1"> > </li><li itemscope itemtype="https://schema.org/ListItem" itemprop="itemListElement" class=""><a itemprop="item" href="/development/index.html"><span itemprop="name">Package development</span></a><meta itemprop="position" content="2"> > </li><li itemscope itemtype="https://schema.org/ListItem" itemprop="itemListElement" class=""><span itemprop="name">Controlling a GPIO input/output pin</span><meta itemprop="position" content="3"></li>
|
||
</ol>
|
||
<div class="topbar-area topbar-area-end" data-area="end">
|
||
<div class="topbar-button topbar-button-edit" data-content-empty="disable" data-width-s="area-more" data-width-m="show" data-width-l="show">
|
||
<span class="btn cstyle button link noborder notitle interactive"><a href="https://github.com/gokrazy/gokrazy/tree/master/website/content/development/gpio.md" rel="external" title="Edit (CTRL+ALT+w)"><i class="fa-fw fas fa-pen"></i></a></span>
|
||
</div>
|
||
<div class="topbar-button topbar-button-more" data-content-empty="hide" data-width-s="show" data-width-m="show" data-width-l="show">
|
||
<span class="btn cstyle button link noborder notitle interactive"><button onclick="toggleTopbarFlyout(this)" type="button" title="More"><i class="fa-fw fas fa-ellipsis-v"></i></button></span>
|
||
<div class="topbar-content">
|
||
<div class="topbar-content-wrapper">
|
||
<div class="topbar-area topbar-area-more" data-area="more">
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</nav>
|
||
<div id="R-main-overlay"></div>
|
||
<main id="R-body-inner" class="highlightable development" tabindex="-1">
|
||
<div class="flex-block-wrapper">
|
||
<article class="default">
|
||
<header class="headline">
|
||
</header>
|
||
|
||
<h1 id="controlling-a-gpio-inputoutput-pin">Controlling a GPIO input/output pin</h1>
|
||
|
||
<p>In this guide, we are using <a href="https://periph.io/" rel="external">periph.io</a>, a library for
|
||
peripheral I/O in Go, to set one of the Raspberry Pi’s General Purpose I/O
|
||
(GPIO) pins to a logical high (3.3V) or low (0V) signal.</p>
|
||
<p>periph.io supports the Raspberry Pi 3, Raspberry Pi Zero 2W and Raspberry Pi 4, starting with version
|
||
<code>v3.6.4</code>.</p>
|
||
<h2 id="connect-gpio-pins-based-on-pinout">Connect GPIO pins based on pinout<span class="btn cstyle anchor copyanchor scrollanchor link noborder notitle interactive"><button type="button" title="Copy link to clipboard"><i class="fa-fw fas fa-link fa-lg"></i></button></span></h2>
|
||
<p>To verify the code is doing what we expect, let’s connect a multimeter as per
|
||
<a href="https://pinout.xyz" rel="external">pinout.xyz</a>’s pinout:</p>
|
||
<p><a href="#R-image-20b9bd57d8debe146b5cd890f0862bff" class="lightbox-link"><img class="lazy lightbox figure-image" loading="lazy" src="/img/raspberry-pi-pinout.png" style="height: auto;width: auto;"></a>
|
||
<a href="javascript:history.back();" class="lightbox-back" id="R-image-20b9bd57d8debe146b5cd890f0862bff"><img class="lazy lightbox lightbox-image" loading="lazy" src="/img/raspberry-pi-pinout.png"></a></p>
|
||
<ul>
|
||
<li>pin number 18 (signal <code>BCM24</code>, labeled <code>24</code> in the pinout above)</li>
|
||
<li>pin number 20 (signal <code>GND</code>)</li>
|
||
</ul>
|
||
<p>We need to set the multimeter to “Voltage measurement, DC (direct current)”.</p>
|
||
<h2 id="setting-an-output-pin-signal">Setting an output pin signal<span class="btn cstyle anchor copyanchor scrollanchor link noborder notitle interactive"><button type="button" title="Copy link to clipboard"><i class="fa-fw fas fa-link fa-lg"></i></button></span></h2>
|
||
<p>To set the pin high and low, alternatingly, with a 5 second frequency, we will
|
||
be using the <code>hello-gpio</code> program, which is a slightly modified version of the
|
||
example at <a href="https://periph.io/device/led/" rel="external">periph.io/device/led</a>:</p>
|
||
<div class="highlight actionbar-wrapper wrap-code" dir="auto"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-go" data-lang="go"><span style="display:flex;"><span><span style="color:#f92672">package</span> <span style="color:#a6e22e">main</span>
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#f92672">import</span> (
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"log"</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"time"</span>
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"periph.io/x/conn/v3/gpio"</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">host</span> <span style="color:#e6db74">"periph.io/x/host/v3"</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"periph.io/x/host/v3/rpi"</span>
|
||
</span></span><span style="display:flex;"><span>)
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">func</span> <span style="color:#a6e22e">doGPIO</span>() <span style="color:#66d9ef">error</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"Loading periph.io drivers"</span>)
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Load periph.io drivers:</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">_</span>, <span style="color:#a6e22e">err</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">host</span>.<span style="color:#a6e22e">Init</span>(); <span style="color:#a6e22e">err</span> <span style="color:#f92672">!=</span> <span style="color:#66d9ef">nil</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">return</span> <span style="color:#a6e22e">err</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"Toggling GPIO forever"</span>)
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">t</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">time</span>.<span style="color:#a6e22e">NewTicker</span>(<span style="color:#ae81ff">5</span> <span style="color:#f92672">*</span> <span style="color:#a6e22e">time</span>.<span style="color:#a6e22e">Second</span>)
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">for</span> <span style="color:#a6e22e">l</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">gpio</span>.<span style="color:#a6e22e">Low</span>; ; <span style="color:#a6e22e">l</span> = !<span style="color:#a6e22e">l</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"setting GPIO pin number 18 (signal BCM24) to %v"</span>, <span style="color:#a6e22e">l</span>)
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Lookup a pin by its location on the board:</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">err</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">rpi</span>.<span style="color:#a6e22e">P1_18</span>.<span style="color:#a6e22e">Out</span>(<span style="color:#a6e22e">l</span>); <span style="color:#a6e22e">err</span> <span style="color:#f92672">!=</span> <span style="color:#66d9ef">nil</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">return</span> <span style="color:#a6e22e">err</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span> <span style="color:#f92672"><-</span><span style="color:#a6e22e">t</span>.<span style="color:#a6e22e">C</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span>}
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">func</span> <span style="color:#a6e22e">main</span>() {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">err</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">doGPIO</span>(); <span style="color:#a6e22e">err</span> <span style="color:#f92672">!=</span> <span style="color:#66d9ef">nil</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Fatal</span>(<span style="color:#a6e22e">err</span>)
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span>}</span></span></code></pre></div>
|
||
<p>You have two options to run this program on your Raspberry Pi:</p>
|
||
<ol>
|
||
<li>Use <code>gok run</code> to temporarily run this program on a running gokrazy instance.</li>
|
||
<li>Use <code>gok add</code> to permanently include this program in your gokrazy instance:</li>
|
||
</ol>
|
||
<div class="highlight actionbar-wrapper wrap-code" dir="auto"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#75715e"># From the hello-gpio directory, run:</span>
|
||
</span></span><span style="display:flex;"><span>gok add .
|
||
</span></span><span style="display:flex;"><span><span style="color:#75715e"># Then, deploy as usual:</span>
|
||
</span></span><span style="display:flex;"><span>gok update</span></span></code></pre></div>
|
||
<p>At this point, we should be able to see the high/low signal on the multimeter,
|
||
alternating between 3.3V (high) and 0V (low) every 5 seconds:</p>
|
||
<p><a href="/img/2020-06-15-gpio.jpg"><img src="/img/2020-06-15-gpio.thumb.jpg" srcset="/img/2020-06-15-gpio.thumb.2x.jpg 2x,/img/2020-06-15-gpio.thumb.3x.jpg 3x" width="700" style="border: 1px solid grey; margin-bottom: 2em; margin-top: 1em"></a></p>
|
||
<h2 id="setting-up-an-input-pin">Setting up an input pin<span class="btn cstyle anchor copyanchor scrollanchor link noborder notitle interactive"><button type="button" title="Copy link to clipboard"><i class="fa-fw fas fa-link fa-lg"></i></button></span></h2>
|
||
<p>To setup a Pin as an input and to act on change to High level, such as a button,
|
||
we must poll the Pin periodically because <a href="http://periph.io/" rel="external">periph.io’s</a> edge
|
||
detection, which examples like the
|
||
<a href="https://periph.io/device/button/" rel="external">periph.io/device/button example</a> rely on,
|
||
<a href="https://github.com/gokrazy/gokrazy/issues/233" rel="external">is not available on gokrazy</a>.</p>
|
||
<p>The below example configures a single Pin for Input and uses Go channels to
|
||
signal level changes that can be acted on. Keep in mind that shortening the
|
||
polling interval will increase CPU usage.</p>
|
||
<div class="highlight actionbar-wrapper wrap-code" dir="auto"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-go" data-lang="go"><span style="display:flex;"><span><span style="color:#f92672">package</span> <span style="color:#a6e22e">main</span>
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#f92672">import</span> (
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"log"</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"time"</span>
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"periph.io/x/conn/v3/gpio"</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#e6db74">"periph.io/x/conn/v3/gpio/gpioreg"</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">host</span> <span style="color:#e6db74">"periph.io/x/host/v3"</span>
|
||
</span></span><span style="display:flex;"><span>)
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">type</span> <span style="color:#a6e22e">pinLevelMessage</span> <span style="color:#66d9ef">struct</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">State</span> <span style="color:#a6e22e">gpio</span>.<span style="color:#a6e22e">Level</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">Reset</span> <span style="color:#a6e22e">gpio</span>.<span style="color:#a6e22e">Level</span>
|
||
</span></span><span style="display:flex;"><span>}
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">func</span> <span style="color:#a6e22e">setupGPIOInput</span>(<span style="color:#a6e22e">pinName</span> <span style="color:#66d9ef">string</span>, <span style="color:#a6e22e">levelChan</span> <span style="color:#66d9ef">chan</span> <span style="color:#a6e22e">pinLevelMessage</span>) (<span style="color:#a6e22e">gpio</span>.<span style="color:#a6e22e">PinIO</span>, <span style="color:#66d9ef">error</span>) {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"Loading periph.io drivers"</span>)
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">_</span>, <span style="color:#a6e22e">err</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">host</span>.<span style="color:#a6e22e">Init</span>(); <span style="color:#a6e22e">err</span> <span style="color:#f92672">!=</span> <span style="color:#66d9ef">nil</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">return</span> <span style="color:#66d9ef">nil</span>, <span style="color:#a6e22e">err</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Find Pin by name</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">p</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">gpioreg</span>.<span style="color:#a6e22e">ByName</span>(<span style="color:#a6e22e">pinName</span>)
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Configure Pin for input, configure pull as needed</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Edge mode is currently not supported</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">err</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">p</span>.<span style="color:#a6e22e">In</span>(<span style="color:#a6e22e">gpio</span>.<span style="color:#a6e22e">PullNoChange</span>, <span style="color:#a6e22e">gpio</span>.<span style="color:#a6e22e">NoEdge</span>); <span style="color:#a6e22e">err</span> <span style="color:#f92672">!=</span> <span style="color:#66d9ef">nil</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">return</span> <span style="color:#66d9ef">nil</span>, <span style="color:#a6e22e">err</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Setup Input signalling</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">go</span> <span style="color:#66d9ef">func</span>() {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">lastLevel</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">p</span>.<span style="color:#a6e22e">Read</span>()
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// How often to poll levels, 100-150ms is fairly responsive unless</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// button presses are very fast.</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Shortening the polling interval <100ms significantly increases</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// CPU load.</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">for</span> <span style="color:#66d9ef">range</span> <span style="color:#a6e22e">time</span>.<span style="color:#a6e22e">Tick</span>(<span style="color:#ae81ff">100</span> <span style="color:#f92672">*</span> <span style="color:#a6e22e">time</span>.<span style="color:#a6e22e">Millisecond</span>) {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">currentLevel</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">p</span>.<span style="color:#a6e22e">Read</span>()
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"level: %v"</span>, <span style="color:#a6e22e">currentLevel</span>)
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">currentLevel</span> <span style="color:#f92672">!=</span> <span style="color:#a6e22e">lastLevel</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">levelChan</span> <span style="color:#f92672"><-</span> <span style="color:#a6e22e">pinLevelMessage</span>{<span style="color:#a6e22e">State</span>: <span style="color:#a6e22e">currentLevel</span>, <span style="color:#a6e22e">Reset</span>: !<span style="color:#a6e22e">currentLevel</span>}
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">lastLevel</span> = <span style="color:#a6e22e">currentLevel</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span> }()
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">return</span> <span style="color:#a6e22e">p</span>, <span style="color:#66d9ef">nil</span>
|
||
</span></span><span style="display:flex;"><span>}
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">func</span> <span style="color:#a6e22e">main</span>() {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Channel for communicating Pin levels</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">levelChan</span> <span style="color:#f92672">:=</span> make(<span style="color:#66d9ef">chan</span> <span style="color:#a6e22e">pinLevelMessage</span>)
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">p</span>, <span style="color:#a6e22e">err</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">setupGPIOInput</span>(<span style="color:#e6db74">"GPIO4"</span>, <span style="color:#a6e22e">levelChan</span>)
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">err</span> <span style="color:#f92672">!=</span> <span style="color:#66d9ef">nil</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Fatal</span>(<span style="color:#a6e22e">err</span>)
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Main loop, act on level changes</span>
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">for</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">select</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">case</span> <span style="color:#a6e22e">msg</span> <span style="color:#f92672">:=</span> <span style="color:#f92672"><-</span><span style="color:#a6e22e">levelChan</span>:
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">msg</span>.<span style="color:#a6e22e">State</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"Pin %s is High, processing high state tasks"</span>, <span style="color:#a6e22e">p</span>.<span style="color:#a6e22e">Name</span>())
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Process high state tasks</span>
|
||
</span></span><span style="display:flex;"><span> } <span style="color:#66d9ef">else</span> <span style="color:#66d9ef">if</span> <span style="color:#a6e22e">msg</span>.<span style="color:#a6e22e">Reset</span> {
|
||
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">log</span>.<span style="color:#a6e22e">Printf</span>(<span style="color:#e6db74">"Pin %s is Low, resetting to wait for high state"</span>, <span style="color:#a6e22e">p</span>.<span style="color:#a6e22e">Name</span>())
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Process resetting logic, if any</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">default</span>:
|
||
</span></span><span style="display:flex;"><span> <span style="color:#75715e">// Any other ongoing tasks</span>
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span> }
|
||
</span></span><span style="display:flex;"><span>}</span></span></code></pre></div>
|
||
|
||
<footer class="footline">
|
||
</footer>
|
||
</article>
|
||
</div>
|
||
</main>
|
||
</div>
|
||
<aside id="R-sidebar" class="default-animation">
|
||
<div id="R-header-topbar" class="default-animation"></div>
|
||
<div id="R-header-wrapper" class="default-animation">
|
||
<div id="R-header" class="default-animation">
|
||
<img src="/logo.svg" width="100%" alt="gokrazy logo" title="gokrazy logo">
|
||
|
||
</div>
|
||
<search><form action="/search/index.html" method="get">
|
||
<div class="searchbox default-animation">
|
||
<button class="search-detail" type="submit" title="Search (CTRL+ALT+f)"><i class="fas fa-search"></i></button>
|
||
<label class="a11y-only" for="R-search-by">Search</label>
|
||
<input data-search-input id="R-search-by" name="search-by" class="search-by" type="search" placeholder="Search...">
|
||
<button class="search-clear" type="button" data-search-clear="" title="Clear search"><i class="fas fa-times" title="Clear search"></i></button>
|
||
</div>
|
||
</form></search>
|
||
</div>
|
||
<div id="R-homelinks" class="default-animation homelinks">
|
||
<div class="R-menu-divider default-animation">
|
||
<hr class="padding">
|
||
</div>
|
||
<div class="R-sidebarmenu R-shortcutmenu-homelinks">
|
||
<ul class="space collapsible-menu">
|
||
<li class="" data-nav-url="/index.html"><a class="padding" href="/index.html"><i class="fa-fw fas fa-home"></i> Home</a></li>
|
||
</ul>
|
||
</div>
|
||
<div class="R-menu-divider default-animation">
|
||
<hr class="padding">
|
||
</div>
|
||
<div class="R-sidebarmenu R-shortcutmenu-headercontrols">
|
||
<ul class="">
|
||
</ul>
|
||
</div>
|
||
<div class="R-menu-divider default-animation">
|
||
<hr class="padding">
|
||
</div>
|
||
</div>
|
||
<div id="R-content-wrapper" class="highlightable">
|
||
<div class="R-sidebarmenu R-shortcutmenu-main">
|
||
<ul class="enlarge morespace collapsible-menu">
|
||
<li class="" data-nav-url="/quickstart/index.html"><a class="padding" href="/quickstart/index.html"><b>1. </b>Quickstart</a></li>
|
||
<li class="" data-nav-url="/platforms/index.html"><a class="padding" href="/platforms/index.html"><b>2. </b>Supported platforms</a></li>
|
||
<li class="" data-nav-url="/userguide/index.html"><a class="padding" href="/userguide/index.html"><b>3. </b>Configuration</a><ul id="R-subsections-74b4df3a3d9365853f09e9f1dfe7bbba" class="collapsible-menu"></ul></li>
|
||
<li class="" data-nav-url="/packages/index.html"><a class="padding" href="/packages/index.html"><b>4. </b>Available packages</a><ul id="R-subsections-bdf1e8ce92aa8ff6883c617f10480430" class="collapsible-menu"></ul></li>
|
||
<li class="parent " data-nav-url="/development/index.html"><a class="padding" href="/development/index.html"><b>5. </b>Package development</a><ul id="R-subsections-54b0ce3c97b111c8cd4d107325fd580c" class="collapsible-menu">
|
||
<li class="" data-nav-url="/development/process-interface/index.html"><a class="padding" href="/development/process-interface/index.html">Process interface / requirements</a></li>
|
||
<li class="active " data-nav-url="/development/gpio/index.html"><a class="padding" href="/development/gpio/index.html">Controlling a GPIO input/output pin</a></li>
|
||
<li class="" data-nav-url="/development/modules/index.html"><a class="padding" href="/development/modules/index.html">Working with Go modules</a></li>
|
||
<li class="" data-nav-url="/development/buildtags/index.html"><a class="padding" href="/development/buildtags/index.html">The gokrazy Go build tag</a></li>
|
||
<li class="" data-nav-url="/development/non-go/index.html"><a class="padding" href="/development/non-go/index.html">Non-Go Prototyping</a></li></ul></li>
|
||
</ul>
|
||
</div>
|
||
<div class="R-sidebarmenu R-shortcutmenu-shortcuts">
|
||
<div class="nav-title padding">More</div>
|
||
<ul class="space collapsible-menu">
|
||
<li class="" data-nav-url="https://github.com/gokrazy/gokrazy"><a class="padding" href="https://github.com/gokrazy/gokrazy" rel="external"><i class='fab fa-github'></i> GitHub repo</a></li>
|
||
</ul>
|
||
</div>
|
||
<div id="R-footer-margin"></div>
|
||
<div class="R-menu-divider default-animation">
|
||
<hr class="padding">
|
||
</div>
|
||
<div class="R-sidebarmenu R-shortcutmenu-footercontrols">
|
||
<ul class="">
|
||
</ul>
|
||
</div>
|
||
<div id="R-footer"><p>Built with <a href="https://github.com/McShelby/hugo-theme-relearn" title="love"><i class="fas fa-heart"></i></a> by <a href="https://gohugo.io/">Hugo</a></p></div>
|
||
</div>
|
||
</aside>
|
||
<script src="/js/perfect-scrollbar/perfect-scrollbar.min.js?1782408721" defer></script>
|
||
<script src="/js/theme.min.js?1782408721" defer></script>
|
||
<div id="toast-container" role="status" aria-live="polite" aria-atomic="false"></div>
|
||
</body>
|
||
</html>
|