begriffs open source - cmsis/blob - main/Core/html/group__ITM__Debug__gr.html

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  46    <div id="projectname">CMSIS-Core (Cortex-M)
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  55    <div id="projectbrief">CMSIS-Core support for Cortex-M processor-based devices</div>
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 130   <div class="summary">
 131 <a href="#func-members">Functions</a> &#124;
 132 <a href="#var-members">Variables</a>  </div>
 133   <div class="headertitle"><div class="title">Debug Access</div></div>
 134 </div><!--header-->
 135 <div class="contents">
 136
 137 <p>Debug Access to the Instrumented Trace Macrocell (ITM)
 138 <a href="#details">More...</a></p>
 139 <table class="memberdecls">
 140 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a id="func-members" name="func-members"></a>
 141 Functions</h2></td></tr>
 142 <tr class="memitem:gaaa7c716331f74d644bf6bf25cd3392d1"><td class="memItemLeft" align="right" valign="top">uint32_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__ITM__Debug__gr.html#gaaa7c716331f74d644bf6bf25cd3392d1">ITM_SendChar</a> (uint32_t ch)</td></tr>
 143 <tr class="memdesc:gaaa7c716331f74d644bf6bf25cd3392d1"><td class="mdescLeft">&#160;</td><td class="mdescRight">Transmits a character via channel 0.  <br /></td></tr>
 144 <tr class="separator:gaaa7c716331f74d644bf6bf25cd3392d1"><td class="memSeparator" colspan="2">&#160;</td></tr>
 145 <tr class="memitem:ga37b8f41cae703b5ff6947e271065558c"><td class="memItemLeft" align="right" valign="top">int32_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__ITM__Debug__gr.html#ga37b8f41cae703b5ff6947e271065558c">ITM_ReceiveChar</a> (void)</td></tr>
 146 <tr class="memdesc:ga37b8f41cae703b5ff6947e271065558c"><td class="mdescLeft">&#160;</td><td class="mdescRight">ITM Receive Character.  <br /></td></tr>
 147 <tr class="separator:ga37b8f41cae703b5ff6947e271065558c"><td class="memSeparator" colspan="2">&#160;</td></tr>
 148 <tr class="memitem:ga7f9bbabd9756d1a7eafb2d9bf27e0535"><td class="memItemLeft" align="right" valign="top">int32_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__ITM__Debug__gr.html#ga7f9bbabd9756d1a7eafb2d9bf27e0535">ITM_CheckChar</a> (void)</td></tr>
 149 <tr class="memdesc:ga7f9bbabd9756d1a7eafb2d9bf27e0535"><td class="mdescLeft">&#160;</td><td class="mdescRight">ITM Check Character.  <br /></td></tr>
 150 <tr class="separator:ga7f9bbabd9756d1a7eafb2d9bf27e0535"><td class="memSeparator" colspan="2">&#160;</td></tr>
 151 </table><table class="memberdecls">
 152 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a id="var-members" name="var-members"></a>
 153 Variables</h2></td></tr>
 154 <tr class="memitem:ga12e68e55a7badc271b948d6c7230b2a8"><td class="memItemLeft" align="right" valign="top">volatile int32_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__ITM__Debug__gr.html#ga12e68e55a7badc271b948d6c7230b2a8">ITM_RxBuffer</a></td></tr>
 155 <tr class="memdesc:ga12e68e55a7badc271b948d6c7230b2a8"><td class="mdescLeft">&#160;</td><td class="mdescRight">external variable to receive characters <br  />
 156   <br /></td></tr>
 157 <tr class="separator:ga12e68e55a7badc271b948d6c7230b2a8"><td class="memSeparator" colspan="2">&#160;</td></tr>
 158 </table>
 159 <a name="details" id="details"></a><h2 class="groupheader">Description</h2>
 160 <p>Debug Access to the Instrumented Trace Macrocell (ITM) </p>
 161 <p>CMSIS provides additional debug functions to enlarge the Debug Access. Data can be transmitted via a certain global buffer variable towards the target system. <br  />
 162 </p>
 163 <p>The Cortex-M3 / Cortex-M4 / Cortex-M7 incorporates the <b>Instrumented Trace Macrocell (ITM)</b> that provides together with the <b>Serial Wire Output (SWO)</b> trace capabilities for the microcontroller system. The ITM has 32 communication channels; two ITM communication channels are used by CMSIS to output the following information:</p>
 164 <ul>
 165 <li><b>ITM Channel 0</b>: implements the <a class="el" href="group__ITM__Debug__gr.html#gaaa7c716331f74d644bf6bf25cd3392d1">ITM_SendChar</a> function which can be used for printf-style output via the debug interface.</li>
 166 <li><b>ITM Channel 31</b>: is reserved for the RTOS kernel and can be used for kernel awareness debugging.</li>
 167 </ul>
 168 <dl class="section remark"><dt>Remarks</dt><dd><ul>
 169 <li>ITM channels have 4 groups with 8 channels each, whereby each group can be configured for access rights in the Unprivileged level.</li>
 170 <li>The ITM channel 0 can be enabled for the user task.</li>
 171 <li>ITM channel 31 can be accessed only in Privileged mode from the RTOS kernel itself. The ITM channel 31 has been selected for the RTOS kernel because some kernels may use the Privileged level for program execution.</li>
 172 </ul>
 173 </dd></dl>
 174 <hr  />
 175 <p> <br  />
 176  </p>
 177 <h1><a class="anchor" id="ITM_debug_uv"></a>
 178 ITM Debugger Support</h1>
 179 <p>A debugger may support a <b>Debug (printf) Viewer</b> window to display data.</p>
 180 <p><b>Direction: Microcontroller &ndash;&gt; Debugger:</b></p><ul>
 181 <li>Characters received via ITM communication channel 0 are written in a printf-style to the <b>Debug (printf) Viewer</b> window.</li>
 182 </ul>
 183 <p><b>Direction: Debugger &ndash;&gt; Microcontroller:</b></p><ul>
 184 <li>Check if <a class="el" href="group__ITM__Debug__gr.html#ga12e68e55a7badc271b948d6c7230b2a8">ITM_RxBuffer</a> variable is available (only performed once).</li>
 185 <li>Read the character from the <b>Debug (printf) Viewer</b> window.</li>
 186 <li>If <a class="el" href="group__ITM__Debug__gr.html#ga12e68e55a7badc271b948d6c7230b2a8">ITM_RxBuffer</a> is empty, write character to <a class="el" href="group__ITM__Debug__gr.html#ga12e68e55a7badc271b948d6c7230b2a8">ITM_RxBuffer</a>.</li>
 187 </ul>
 188 <dl class="section note"><dt>Note</dt><dd>The current solution does not use a buffer mechanism for transmitting the characters.</dd></dl>
 189 <hr  />
 190 <p> <br  />
 191  </p>
 192 <h1><a class="anchor" id="itm_debug_ex"></a>
 193 Example:</h1>
 194 <p>Example for the usage of the ITM Channel 31 for RTOS Kernels:</p>
 195 <div class="fragment"><div class="line"><span class="comment">// check if debugger connected and ITM channel enabled for tracing</span></div>
 196 <div class="line"><span class="keywordflow">if</span> ((CoreDebug-&gt;DEMCR &amp; CoreDebug_DEMCR_TRCENA) &amp;&amp;</div>
 197 <div class="line">    (ITM-&gt;TCR &amp; ITM_TCR_ITMENA) &amp;&amp;</div>
 198 <div class="line">    (ITM-&gt;TER &amp; (1UL &gt;&gt; 31))) {</div>
 199 <div class="line">    </div>
 200 <div class="line">    <span class="comment">// transmit trace data</span></div>
 201 <div class="line">    <span class="keywordflow">while</span> (ITM-&gt;PORT31_U32 == 0);</div>
 202 <div class="line">    ITM-&gt;PORT[31].u8 = task_id;      <span class="comment">// id of next task</span></div>
 203 <div class="line">    <span class="keywordflow">while</span> (ITM-&gt;PORT[31].u32 == 0);</div>
 204 <div class="line">    ITM-&gt;PORT[31].u32 = task_status; <span class="comment">// status information</span></div>
 205 <div class="line">}</div>
 206 </div><!-- fragment --> <h2 class="groupheader">Function Documentation</h2>
 207 <a id="ga7f9bbabd9756d1a7eafb2d9bf27e0535" name="ga7f9bbabd9756d1a7eafb2d9bf27e0535"></a>
 208 <h2 class="memtitle"><span class="permalink"><a href="#ga7f9bbabd9756d1a7eafb2d9bf27e0535">&#9670;&#160;</a></span>ITM_CheckChar()</h2>
 209
 210 <div class="memitem">
 211 <div class="memproto">
 212       <table class="memname">
 213         <tr>
 214           <td class="memname">int32_t ITM_CheckChar </td>
 215           <td>(</td>
 216           <td class="paramtype">void&#160;</td>
 217           <td class="paramname"></td><td>)</td>
 218           <td></td>
 219         </tr>
 220       </table>
 221 </div><div class="memdoc">
 222
 223 <p>ITM Check Character. </p>
 224 <p>This function reads the external variable <a class="el" href="group__ITM__Debug__gr.html#ga12e68e55a7badc271b948d6c7230b2a8">ITM_RxBuffer</a> and checks whether a character is available or not.</p>
 225 <dl class="section return"><dt>Returns</dt><dd><br  />
 226 <ul>
 227 <li>=0 - No character available</li>
 228 <li>=1 - Character available </li>
 229 </ul>
 230 </dd></dl>
 231
 232 </div>
 233 </div>
 234 <a id="ga37b8f41cae703b5ff6947e271065558c" name="ga37b8f41cae703b5ff6947e271065558c"></a>
 235 <h2 class="memtitle"><span class="permalink"><a href="#ga37b8f41cae703b5ff6947e271065558c">&#9670;&#160;</a></span>ITM_ReceiveChar()</h2>
 236
 237 <div class="memitem">
 238 <div class="memproto">
 239       <table class="memname">
 240         <tr>
 241           <td class="memname">int32_t ITM_ReceiveChar </td>
 242           <td>(</td>
 243           <td class="paramtype">void&#160;</td>
 244           <td class="paramname"></td><td>)</td>
 245           <td></td>
 246         </tr>
 247       </table>
 248 </div><div class="memdoc">
 249
 250 <p>ITM Receive Character. </p>
 251 <p>This function inputs a character via the external variable <a class="el" href="group__ITM__Debug__gr.html#ga12e68e55a7badc271b948d6c7230b2a8">ITM_RxBuffer</a>. It returns when no debugger is connected that has booked the output. <br  />
 252  It is blocking when a debugger is connected, but the previously sent character has not been transmitted.</p>
 253 <dl class="section return"><dt>Returns</dt><dd><br  />
 254 <ul>
 255 <li>Received character</li>
 256 <li>=1 - No character received </li>
 257 </ul>
 258 </dd></dl>
 259
 260 </div>
 261 </div>
 262 <a id="gaaa7c716331f74d644bf6bf25cd3392d1" name="gaaa7c716331f74d644bf6bf25cd3392d1"></a>
 263 <h2 class="memtitle"><span class="permalink"><a href="#gaaa7c716331f74d644bf6bf25cd3392d1">&#9670;&#160;</a></span>ITM_SendChar()</h2>
 264
 265 <div class="memitem">
 266 <div class="memproto">
 267       <table class="memname">
 268         <tr>
 269           <td class="memname">uint32_t ITM_SendChar </td>
 270           <td>(</td>
 271           <td class="paramtype">uint32_t&#160;</td>
 272           <td class="paramname"><em>ch</em></td><td>)</td>
 273           <td></td>
 274         </tr>
 275       </table>
 276 </div><div class="memdoc">
 277
 278 <p>Transmits a character via channel 0. </p>
 279 <p>This function transmits a character via the ITM channel 0. It returns when no debugger is connected that has booked the output. <br  />
 280  It is blocking when a debugger is connected, but the previously sent character has not been transmitted.</p>
 281 <dl class="params"><dt>Parameters</dt><dd>
 282   <table class="params">
 283     <tr><td class="paramdir">[in]</td><td class="paramname">ch</td><td>Character to transmit</td></tr>
 284   </table>
 285   </dd>
 286 </dl>
 287 <dl class="section return"><dt>Returns</dt><dd>Character to transmit </dd></dl>
 288
 289 </div>
 290 </div>
 291 <h2 class="groupheader">Variable Documentation</h2>
 292 <a id="ga12e68e55a7badc271b948d6c7230b2a8" name="ga12e68e55a7badc271b948d6c7230b2a8"></a>
 293 <h2 class="memtitle"><span class="permalink"><a href="#ga12e68e55a7badc271b948d6c7230b2a8">&#9670;&#160;</a></span>ITM_RxBuffer</h2>
 294
 295 <div class="memitem">
 296 <div class="memproto">
 297       <table class="memname">
 298         <tr>
 299           <td class="memname">volatile int32_t ITM_RxBuffer</td>
 300         </tr>
 301       </table>
 302 </div><div class="memdoc">
 303
 304 <p>external variable to receive characters <br  />
 305  </p>
 306
 307 </div>
 308 </div>
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