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<title>11.1 Resetting and analyzing</title>
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<a name="1204406"> </a><font color="#003366" face="Verdana, Arial, Helvetica, sans-serif">11.1 Resetting and analyzing</font>
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<a name="1204407"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">An ST20-C2 is reset in order to initialize its internal state and external memory interface, and then to boot. If the processor is active when it is reset it stops operation immediately. </font>
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<a name="1204408"> </a><font color="#003366" face="Verdana, Arial, Helvetica, sans-serif">Hardware reset and analyze</font>
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<a name="1204409"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">An ST20-C2 is reset by pulsing the <span class=Signal>Reset</span> pin while holding the <span class=Signal>Analyse</span> pin low. </font>
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<a name="1204410"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">An ST20-C2 is analyzed in order to investigate its internal state. It stops operation in a way that preserves much of its state and then starts to boot; it does not initialize its external memory interface. An ST20-C2 is analyzed by taking and holding the <span class=Signal>Analyse</span> pin high, then pulsing the <span class=Signal>Reset</span> pin and taking the <span class=Signal>Analyse</span> pin low. </font>
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<a name="1204411"> </a><font color="#003366" face="Verdana, Arial, Helvetica, sans-serif">Software reset</font>
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<a name="1204427"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">The <strong>reboot</strong> instruction performs a `software reset' causing the processor to behave as if it has received a hardware reset. It then proceeds to boot according to the methods described below.
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<caption><b><i><font face="Verdana, Arial, Helvetica, sans-serif"><a name="1206584"> </a><font face="Helvetica">Table 74: Software reset instruction</font></font></i></b></caption>
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<th><font face="Verdana, Arial, Helvetica, sans-serif" color="#003366"><a name="1206575"> </a><font face="Verdana, Arial, Helvetica, sans-serif">Mnemonic</font></font></th>
<th><font face="Verdana, Arial, Helvetica, sans-serif" color="#003366"><a name="1206577"> </a><font face="Verdana, Arial, Helvetica, sans-serif">Name</font></font></th>
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<td><font face="Verdana, Arial, Helvetica, sans-serif"><a name="1206580"> </a><div ><font size=2><strong>reboot</strong></font></div></font></td>
<td><font face="Verdana, Arial, Helvetica, sans-serif"><a name="1206582"> </a><div ><font size=2>Software reset</font></div></font></td>
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<a name="1204428"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">Executing <strong>reboot</strong> only causes the processor to be reset and any subsystems integrated with the processor are unaffected. This differs from a hardware reset where (normally) all subsystems also receive a reset signal. It is the system designers' responsibility to ensure that all subsystems are in a reset state before a <strong>reboot</strong> is executed. If subsystems are not reset first then after a <strong>reboot</strong> they may return scheduling requests to the processor which refer to processes that have been destroyed by the software reset. This causes unpredictable results.</font>
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