204 lines
15 KiB
HTML
204 lines
15 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
|
|
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
|
|
<title>Configuration for Low-Power Modes</title>
|
|
<title>CMSIS-RTOS: Configuration for Low-Power Modes</title>
|
|
<link href="tabs.css" rel="stylesheet" type="text/css"/>
|
|
<link href="cmsis.css" rel="stylesheet" type="text/css" />
|
|
<script type="text/javascript" src="jquery.js"></script>
|
|
<script type="text/javascript" src="dynsections.js"></script>
|
|
<script type="text/javascript" src="printComponentTabs.js"></script>
|
|
<link href="navtree.css" rel="stylesheet" type="text/css"/>
|
|
<script type="text/javascript" src="resize.js"></script>
|
|
<script type="text/javascript" src="navtree.js"></script>
|
|
<script type="text/javascript">
|
|
$(document).ready(initResizable);
|
|
$(window).load(resizeHeight);
|
|
</script>
|
|
<link href="search/search.css" rel="stylesheet" type="text/css"/>
|
|
<script type="text/javascript" src="search/search.js"></script>
|
|
<script type="text/javascript">
|
|
$(document).ready(function() { searchBox.OnSelectItem(0); });
|
|
</script>
|
|
</head>
|
|
<body>
|
|
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
|
|
<div id="titlearea">
|
|
<table cellspacing="0" cellpadding="0">
|
|
<tbody>
|
|
<tr style="height: 46px;">
|
|
<td id="projectlogo"><img alt="Logo" src="CMSIS_Logo_Final.png"/></td>
|
|
<td style="padding-left: 0.5em;">
|
|
<div id="projectname">CMSIS-RTOS
|
|
 <span id="projectnumber">Version 1.03</span>
|
|
</div>
|
|
<div id="projectbrief">Real-Time Operating System: API and RTX Reference Implementation.</div>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
</div>
|
|
<!-- end header part -->
|
|
<div id="CMSISnav" class="tabs1">
|
|
<ul class="tablist">
|
|
<script type="text/javascript">
|
|
<!--
|
|
writeComponentTabs.call(this);
|
|
//-->
|
|
</script>
|
|
</ul>
|
|
</div>
|
|
<!-- Generated by Doxygen 1.8.6 -->
|
|
<script type="text/javascript">
|
|
var searchBox = new SearchBox("searchBox", "search",false,'Search');
|
|
</script>
|
|
<div id="navrow1" class="tabs">
|
|
<ul class="tablist">
|
|
<li><a href="index.html"><span>Main Page</span></a></li>
|
|
<li class="current"><a href="pages.html"><span>Usage and Description</span></a></li>
|
|
<li><a href="modules.html"><span>Reference</span></a></li>
|
|
<li>
|
|
<div id="MSearchBox" class="MSearchBoxInactive">
|
|
<span class="left">
|
|
<img id="MSearchSelect" src="search/mag_sel.png"
|
|
onmouseover="return searchBox.OnSearchSelectShow()"
|
|
onmouseout="return searchBox.OnSearchSelectHide()"
|
|
alt=""/>
|
|
<input type="text" id="MSearchField" value="Search" accesskey="S"
|
|
onfocus="searchBox.OnSearchFieldFocus(true)"
|
|
onblur="searchBox.OnSearchFieldFocus(false)"
|
|
onkeyup="searchBox.OnSearchFieldChange(event)"/>
|
|
</span><span class="right">
|
|
<a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
|
|
</span>
|
|
</div>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
</div><!-- top -->
|
|
<div id="side-nav" class="ui-resizable side-nav-resizable">
|
|
<div id="nav-tree">
|
|
<div id="nav-tree-contents">
|
|
<div id="nav-sync" class="sync"></div>
|
|
</div>
|
|
</div>
|
|
<div id="splitbar" style="-moz-user-select:none;"
|
|
class="ui-resizable-handle">
|
|
</div>
|
|
</div>
|
|
<script type="text/javascript">
|
|
$(document).ready(function(){initNavTree('lowPower.html','');});
|
|
</script>
|
|
<div id="doc-content">
|
|
<!-- window showing the filter options -->
|
|
<div id="MSearchSelectWindow"
|
|
onmouseover="return searchBox.OnSearchSelectShow()"
|
|
onmouseout="return searchBox.OnSearchSelectHide()"
|
|
onkeydown="return searchBox.OnSearchSelectKey(event)">
|
|
<a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark"> </span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark"> </span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark"> </span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark"> </span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark"> </span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark"> </span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark"> </span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark"> </span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark"> </span>Macros</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(9)"><span class="SelectionMark"> </span>Groups</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(10)"><span class="SelectionMark"> </span>Pages</a></div>
|
|
|
|
<!-- iframe showing the search results (closed by default) -->
|
|
<div id="MSearchResultsWindow">
|
|
<iframe src="javascript:void(0)" frameborder="0"
|
|
name="MSearchResults" id="MSearchResults">
|
|
</iframe>
|
|
</div>
|
|
|
|
<div class="header">
|
|
<div class="headertitle">
|
|
<div class="title">Configuration for Low-Power Modes </div> </div>
|
|
</div><!--header-->
|
|
<div class="contents">
|
|
<div class="textblock"><p>The system thread <b>os_idle_demon</b> can be use to switch the system into a low-power mode. The easiest form to enter a low-power mode is the execution of the <code>__WFE</code> function that puts the processor into a sleep mode where it waits for an event.</p>
|
|
<p><b>Configuration Example:</b></p>
|
|
<div class="fragment"><div class="line"><span class="preprocessor">#include "device.h"</span> <span class="comment">/* Device definitions */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"><span class="keywordtype">void</span> <a class="code" href="group__RTX__Global__Functions.html#gafb4dc4d3dff8343a393726d2860282e4">os_idle_demon</a> (<span class="keywordtype">void</span>) {</div>
|
|
<div class="line"> <span class="comment">/* The idle demon is a system thread, running when no other thread is */</span></div>
|
|
<div class="line"> <span class="comment">/* ready to run. */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <span class="keywordflow">for</span> (;;) {</div>
|
|
<div class="line"> __WFE(); <span class="comment">/* Enter sleep mode */</span></div>
|
|
<div class="line"> }</div>
|
|
<div class="line">}</div>
|
|
</div><!-- fragment --><dl class="section note"><dt>Note</dt><dd><code>__WFE()</code> is not available at every Cortex-M implementation. Check device manuals for availability.</dd></dl>
|
|
<h1><a class="anchor" id="TickLess"></a>
|
|
Tick-less operation</h1>
|
|
<p>CMSIS-RTOS RTX provides extension for tick-less operation which is useful for applications that use extensively low-power modes where the SysTick timer is also disabled. To provide a time-tick in such power-saving modes a wake-up timer is used to derive timer intervals. The RTX functions <a class="el" href="group__RTX__Global__Functions.html#ga3e9c57746ccbdfe90464ad50513c569e">os_suspend</a> and <a class="el" href="group__RTX__Global__Functions.html#ga1b85a217d43e6b971ffcf24f8aae1c33">os_resume</a> control the tick-less operation.</p>
|
|
<p>Using this functions allows the RTX thread scheduler to stop the periodic kernel tick interrupt. When all active threads are suspended, the system enters power-down and calculates how long it can stay in this power-down mode. In the power-down mode the processor and potentially peripherals can be switched off. Only a wake-up timer must remain powered, because this timer is responsible to wake-up the system after the power-down period expires.</p>
|
|
<p>The tick-less operation is controlled from the <a class="el" href="group__RTX__Global__Functions.html#gafb4dc4d3dff8343a393726d2860282e4">os_idle_demon</a> thread. The wake-up timeout value is set before the system enters the power-down mode. The function <a class="el" href="group__RTX__Global__Functions.html#ga3e9c57746ccbdfe90464ad50513c569e">os_suspend</a> calculates the wake-up timeout measured in RTX Timer Ticks; this value is used to setup the wake-up timer that runs during the power-down mode of the system.</p>
|
|
<p>Once the system resumes operation (either by a wake-up time out or other interrupts) the RTX thread scheduler is started with the function <a class="el" href="group__RTX__Global__Functions.html#ga1b85a217d43e6b971ffcf24f8aae1c33">os_resume</a>. The parameter <em>sleep_time</em> specifies the time (in RTX Timer Ticks) that the system was in power-down mode.</p>
|
|
<p><b>Code</b> <b>Example</b> </p>
|
|
<div class="fragment"><div class="line"><span class="preprocessor">#include "LPC11Uxx.h"</span> <span class="comment">/* LPC11Uxx definitions */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"><span class="keywordtype">void</span> <a class="code" href="group__RTX__Global__Functions.html#gafb4dc4d3dff8343a393726d2860282e4">os_idle_demon</a> (<span class="keywordtype">void</span>) {</div>
|
|
<div class="line"> <span class="comment">/* The idle demon is a system thread, running when no other thread is */</span></div>
|
|
<div class="line"> <span class="comment">/* ready to run. */</span></div>
|
|
<div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> sleep;</div>
|
|
<div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> tc;</div>
|
|
<div class="line"> </div>
|
|
<div class="line"> LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 15) | <span class="comment">/* Enable clock for WWDT */</span></div>
|
|
<div class="line"> (1UL << 19); <span class="comment">/* Enable clock for Pin IRQ */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> LPC_SYSCON->PINTSEL[0] = 1; <span class="comment">/* P0.1 selected as INT0 IRQ */</span></div>
|
|
<div class="line"> LPC_SYSCON->STARTERP0 |= (1UL << 0); <span class="comment">/* Enable INT0 wake-up */</span></div>
|
|
<div class="line"> LPC_SYSCON->STARTERP1 |= (1UL << 12); <span class="comment">/* Enable WWDT wake-up */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> LPC_SYSCON->WDTOSCCTRL = (3 << 0) | <span class="comment">/* WDOSC DIVSEL=3 */</span></div>
|
|
<div class="line"> (2 << 5); <span class="comment">/* WDOSC FREQ=0.8MHz */</span></div>
|
|
<div class="line"> LPC_SYSCON->PDRUNCFG &= ~(1UL << 6); <span class="comment">/* Power-up WDT Oscillator */</span></div>
|
|
<div class="line"> LPC_SYSCON->PDSLEEPCFG &= ~(1UL << 6); <span class="comment">/* Power WDT Oscillator in PD */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> LPC_WWDT->CLKSEL = (1UL << 0) | <span class="comment">/* Select WDOSC as Clock */</span></div>
|
|
<div class="line"> (1UL << 31); <span class="comment">/* Lock selection */</span></div>
|
|
<div class="line"> LPC_WWDT->WARNINT = 1000; <span class="comment">/* WDT Warning IRQ value */</span></div>
|
|
<div class="line"> LPC_WWDT->MOD = (1UL << 0); <span class="comment">/* Enable WDT */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> NVIC_EnableIRQ(FLEX_INT0_IRQn); <span class="comment">/* Enable INT0 IRQ (wake-up) */</span></div>
|
|
<div class="line"> NVIC_EnableIRQ(WDT_IRQn); <span class="comment">/* Enable WWDT IRQ (wake-up) */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <span class="keywordflow">for</span> (;;) {</div>
|
|
<div class="line"> <span class="comment">/* HERE: include optional user code to be executed when no task runs.*/</span></div>
|
|
<div class="line"> sleep = <a class="code" href="group__RTX__Global__Functions.html#ga3e9c57746ccbdfe90464ad50513c569e">os_suspend</a>(); <span class="comment">/* Suspend RTX thread scheduler */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <span class="keywordflow">if</span> (sleep) { <span class="comment">/* How long can we sleep? */</span></div>
|
|
<div class="line"> <span class="comment">/* "sleep" is in RTX Timer Ticks which is 10ms in this configuration */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <span class="comment">/* Setup WDT wake-up: WDT ticks @25kHz (FREQ/2/(DIVSEL+1)/4) */</span></div>
|
|
<div class="line"> tc = (sleep * 250) + 1000;</div>
|
|
<div class="line"> LPC_WWDT->TC = tc;</div>
|
|
<div class="line"> LPC_WWDT->FEED = 0xAA;</div>
|
|
<div class="line"> LPC_WWDT->FEED = 0x55;</div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <span class="comment">/* Enter Power-down mode */</span></div>
|
|
<div class="line"> LPC_SYSCON->PDAWAKECFG = LPC_SYSCON->PDRUNCFG; <span class="comment">/* Power after wake-up */</span></div>
|
|
<div class="line"> LPC_PMU->PCON = 0x02; <span class="comment">/* Select Power-down mode */</span></div>
|
|
<div class="line"> SCB->SCR = (1UL << 2); <span class="comment">/* Set SLEEPDEEP */</span></div>
|
|
<div class="line"> __WFE(); <span class="comment">/* Enter Power-down mode */</span></div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <span class="comment">/* After Wake-up */</span></div>
|
|
<div class="line"> sleep = (tc - LPC_WWDT->TV) / 250;</div>
|
|
<div class="line"> }</div>
|
|
<div class="line"> </div>
|
|
<div class="line"> <a class="code" href="group__RTX__Global__Functions.html#ga1b85a217d43e6b971ffcf24f8aae1c33">os_resume</a>(sleep); <span class="comment">/* Resume RTX thread scheduler */</span></div>
|
|
<div class="line"> }</div>
|
|
<div class="line">}</div>
|
|
</div><!-- fragment --><dl class="section note"><dt>Note</dt><dd><code>__WFE()</code> is not available at every Cortex-M implementation. Check device manuals for availability. </dd></dl>
|
|
</div></div><!-- contents -->
|
|
</div><!-- doc-content -->
|
|
<!-- start footer part -->
|
|
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
|
|
<ul>
|
|
<li class="navelem"><a class="el" href="index.html">index</a></li><li class="navelem"><a class="el" href="rtxImplementation.html">RTX Implementation</a></li><li class="navelem"><a class="el" href="configure.html">Configure RTX</a></li>
|
|
<li class="footer">Generated on Wed Feb 8 2017 10:21:02 for CMSIS-RTOS by ARM Ltd. All rights reserved.
|
|
<!--
|
|
<a href="http://www.doxygen.org/index.html">
|
|
<img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.6
|
|
-->
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
</body>
|
|
</html>
|