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   &#160;<span id="projectnumber">Version 3.20</span>
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   <div id="projectbrief">CMSIS-CORE support for Cortex-M processor-based devices</div>
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<div class="title">Using CMSIS in Embedded Applications </div>  </div>
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<div class="textblock"><p>To use the CMSIS-CORE the following files are added to the embedded application:</p>
<ul>
<li><a class="el" href="startup_s_pg.html">Startup File startup_&lt;device&gt;.s</a> with reset handler and exception vectors.</li>
<li><a class="el" href="system_c_pg.html">System Configuration Files system_&lt;device&gt;.c and system_&lt;device&gt;.h</a> with general device configuration (i.e. for clock and BUS setup).</li>
<li><a class="el" href="device_h_pg.html">Device Header File &lt;device.h&gt;</a> gives access to processor core and all peripherals.</li>
</ul>
<dl class="section note"><dt>Note</dt><dd>The files <a class="el" href="startup_s_pg.html">Startup File startup_&lt;device&gt;.s</a> and <a class="el" href="system_c_pg.html">System Configuration Files system_&lt;device&gt;.c and system_&lt;device&gt;.h</a> may require application specific adaptations and therefore should be copied into the application project folder prior configuration. The <a class="el" href="device_h_pg.html">Device Header File &lt;device.h&gt;</a> is included in all source files that need device access and can be stored on a central include folder that is generic for all projects.</dd></dl>
<p>The <a class="el" href="startup_s_pg.html">Startup File startup_&lt;device&gt;.s</a> is executed after reset and calls <a class="el" href="group__system__init__gr.html#ga93f514700ccf00d08dbdcff7f1224eb2">SystemInit</a>. After the system initialization control is transferred to the C/C++ run-time library which performs initialization and calls the <b>main</b> function in the user code. In addition the <a class="el" href="startup_s_pg.html">Startup File startup_&lt;device&gt;.s</a> contains all exception and interrupt vectors and implements a default function for every interrupt. It may also contain stack and heap configurations for the user application.</p>
<p>The <a class="el" href="system_c_pg.html">System Configuration Files system_&lt;device&gt;.c and system_&lt;device&gt;.h</a> performs the setup for the processor clock. The variable <a class="el" href="group__system__init__gr.html#gaa3cd3e43291e81e795d642b79b6088e6">SystemCoreClock</a> indicates the CPU clock speed. <a class="el" href="group__system__init__gr.html">System and Clock Configuration</a> describes the minimum feature set. In addition the file may contain functions for the memory BUS setup and clock re-configuration.</p>
<p>The <a class="el" href="device_h_pg.html">Device Header File &lt;device.h&gt;</a> is the central include file that the application programmer is using in the C source code. It provides the following features:</p>
<ul>
<li><a class="el" href="group__peripheral__gr.html">Peripheral Access</a> provides a standardized register layout for all peripherals. Optionally functions for device-specific peripherals may be available.</li>
<li><a class="el" href="group___n_v_i_c__gr.html">Interrupts and Exceptions (NVIC)</a> can be accessed with standardized symbols and functions for the Nested Interrupt Vector Controller (NVIC) are provided.</li>
<li><a class="el" href="group__intrinsic___c_p_u__gr.html">Intrinsic Functions for CPU Instructions</a> allow to access special instructions, for example for activating sleep mode or the NOP instruction.</li>
<li><a class="el" href="group__intrinsic___s_i_m_d__gr.html">Intrinsic Functions for SIMD Instructions [only Cortex-M4]</a> provide access to the DSP-oriented instructions.</li>
<li><a class="el" href="group___sys_tick__gr.html">Systick Timer (SYSTICK)</a> function to configure and start a periodic timer interrupt.</li>
<li><a class="el" href="group___i_t_m___debug__gr.html">Debug Access</a> are functions that allow printf-style I/O via the CoreSight Debug Unit and ITM communication.</li>
</ul>
<div class="image">
<img src="CMSIS_CORE_Files_user.png" alt="CMSIS_CORE_Files_user.png"/>
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CMSIS-CORE User Files</div></div>
<p> The CMSIS-CORE are device specific. In addition, the <a class="el" href="startup_s_pg.html">Startup File startup_&lt;device&gt;.s</a> is also compiler vendor specific. The various compiler vendor tool chains may provide folders that contain the CMSIS files for each supported device. <a class="el" href="_using__a_r_m_pg.html">Using CMSIS with generic ARM Processors</a> explains how to use CMSIS-CORE for ARM processors.</p>
<p>For example, the following files are provided in MDK-ARM to support the STM32F10x Connectivity Line device variants:</p>
<table  class="cmtable">
<tr>
<th>File </th><th>Description  </th></tr>
<tr>
<td>".\ARM\Startup\ST\STM32F10x\startup_stm32f10x_cl.s" </td><td><a class="el" href="startup_s_pg.html">Startup File startup_&lt;device&gt;.s</a> for the STM32F10x Connectivity Line device variants.  </td></tr>
<tr>
<td>".\ARM\Startup\ST\STM32F10x\system_stmf10x.c" </td><td><a class="el" href="system_c_pg.html">System Configuration Files system_&lt;device&gt;.c and system_&lt;device&gt;.h</a> for the STM32F10x device families.  </td></tr>
<tr>
<td>".\ARM\INC\ST\STM32F10x\stm32f10x.h" </td><td><a class="el" href="device_h_pg.html">Device Header File &lt;device.h&gt;</a> for the STM32F10x device families.  </td></tr>
<tr>
<td>".\ARM\INC\ST\STM32F10x\system_stm32f10x.h" </td><td><a class="el" href="system_c_pg.html#system_Device_h_sec">system_Device.h Template File</a> for the STM32F10x device families.  </td></tr>
</table>
<dl class="section note"><dt>Note</dt><dd>The silicon vendors create these device-specific CMSIS-CORE files based on <a class="el" href="_templates_pg.html">Template Files</a> provide by ARM.</dd></dl>
<p>Thereafter, the functions described under <a href="Modules.html"><b>Reference</b> </a> can be used in the application.</p>
<p>A typical example for using the CMSIS layer is provided below. The example is based on a STM32F10x Device.</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include &lt;stm32f10x.h&gt;</span>                           <span class="comment">// File name depends on device used</span></div>
<div class="line"></div>
<div class="line">uint32_t <span class="keyword">volatile</span> msTicks;                       <span class="comment">// Counter for millisecond Interval</span></div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> SysTick_Handler (<span class="keywordtype">void</span>) {                    <span class="comment">// SysTick Interrupt Handler</span></div>
<div class="line">  msTicks++;                                     <span class="comment">// Increment Counter</span></div>
<div class="line">}</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> WaitForTick (<span class="keywordtype">void</span>)  {</div>
<div class="line">  uint32_t curTicks;</div>
<div class="line"></div>
<div class="line">  curTicks = msTicks;                            <span class="comment">// Save Current SysTick Value</span></div>
<div class="line">  <span class="keywordflow">while</span> (msTicks == curTicks)  {                 <span class="comment">// Wait for next SysTick Interrupt</span></div>
<div class="line">    <a class="code" href="group__intrinsic___c_p_u__gr.html#gad3efec76c3bfa2b8528ded530386c563" title="Wait For Event.">__WFE</a> ();                                    <span class="comment">// Power-Down until next Event/Interrupt</span></div>
<div class="line">  }</div>
<div class="line">}</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> TIM1_UP_IRQHandler (<span class="keywordtype">void</span>) {                 <span class="comment">// Timer Interrupt Handler</span></div>
<div class="line">  ;                                              <span class="comment">// Add user code here</span></div>
<div class="line">}</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> timer1_init(<span class="keywordtype">int</span> frequency) {                <span class="comment">// Set up Timer (device specific)</span></div>
<div class="line">  <a class="code" href="group___n_v_i_c__gr.html#ga5bb7f43ad92937c039dee3d36c3c2798" title="Set the priority for an interrupt.">NVIC_SetPriority</a> (TIM1_UP_IRQn, 1);            <span class="comment">// Set Timer priority</span></div>
<div class="line">  <a class="code" href="group___n_v_i_c__gr.html#ga530ad9fda2ed1c8b70e439ecfe80591f" title="Enable an external interrupt.">NVIC_EnableIRQ</a> (TIM1_UP_IRQn);                 <span class="comment">// Enable Timer Interrupt</span></div>
<div class="line">}</div>
<div class="line"></div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> Device_Initialization (<span class="keywordtype">void</span>)  {             <span class="comment">// Configure &amp; Initialize MCU</span></div>
<div class="line">  <span class="keywordflow">if</span> (<a class="code" href="group___sys_tick__gr.html#gabe47de40e9b0ad465b752297a9d9f427" title="System Tick Timer Configuration.">SysTick_Config</a> (<a class="code" href="group__system__init__gr.html#gaa3cd3e43291e81e795d642b79b6088e6" title="Variable to hold the system core clock value.">SystemCoreClock</a> / 1000)) { <span class="comment">// SysTick 1mSec</span></div>
<div class="line">       : <span class="comment">// Handle Error </span></div>
<div class="line">  }</div>
<div class="line">  timer1_init ();                                <span class="comment">// setup device-specific timer</span></div>
<div class="line">}</div>
<div class="line"></div>
<div class="line"></div>
<div class="line"><span class="comment">// The processor clock is initialized by CMSIS startup + system file</span></div>
<div class="line"><span class="keywordtype">void</span> main (<span class="keywordtype">void</span>) {                                   <span class="comment">// user application starts here</span></div>
<div class="line">  Device_Initialization ();                      <span class="comment">// Configure &amp; Initialize MCU</span></div>
<div class="line">  <span class="keywordflow">while</span> (1)  {                                   <span class="comment">// Endless Loop (the Super-Loop)</span></div>
<div class="line">    <a class="code" href="group___core___register__gr.html#gaeb8e5f7564a8ea23678fe3c987b04013" title="Globally disables interrupts and configurable fault handlers.">__disable_irq</a> ();                            <span class="comment">// Disable all interrupts</span></div>
<div class="line">    Get_InputValues ();                          <span class="comment">// Read Values</span></div>
<div class="line">    <a class="code" href="group___core___register__gr.html#ga0f98dfbd252b89d12564472dbeba9c27" title="Globally enables interrupts and configurable fault handlers.">__enable_irq</a> ();                             <span class="comment">// Enable all interrupts </span></div>
<div class="line">    Calculation_Response ();                     <span class="comment">// Calculate Results</span></div>
<div class="line">    Output_Response ();                          <span class="comment">// Output Results</span></div>
<div class="line">    WaitForTick ();                              <span class="comment">// Synchronize to SysTick Timer</span></div>
<div class="line">  }</div>
<div class="line">}</div>
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