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<title>Timers</title>
<meta name="author" content="Cory Sharp, Martin Turon, David Gay" />
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<td>Cory Sharp, Martin Turon, David Gay</td></tr>
<tr class="field"><th class="docinfo-name">Draft-Created:</th><td class="field-body">22-Sep-2004</td>
</tr>
-<tr class="field"><th class="docinfo-name">Draft-Version:</th><td class="field-body">1.8</td>
+<tr class="field"><th class="docinfo-name">Draft-Version:</th><td class="field-body">1.9</td>
</tr>
<tr class="field"><th class="docinfo-name">Draft-Modified:</th><td class="field-body">2007-05-23</td>
</tr>
is motivated by the common availability of hardware clocks driven
by a 32768Hz crystal.</p>
<p>Examples of widths are 8-bit, 16-bit, 32-bit, and 64-bit. The width
-for timer interfaces and components SHOULD be 32-bits. That is, for
-lack of a good reason, timer interfaces should expose a 32-bit
-interface. In a number of circumstances there are good reasons not
-to expose a 32-bit interface. This TEP emphasizes 32-bit widths
-while reasonably accommodating other widths.</p>
+for timer interfaces and components SHOULD be 32-bits. This TEP
+emphasizes 32-bit widths while reasonably accommodating other widths -
+a particular platform may have good reasons not to expose a 32-bit
+interface.</p>
<p>Accuracy reflects how closely a component conforms to the precision it
claims to provide. Accuracy is affected by issues such as clock drift (much
higher for internal vs crystal oscillators) and hardware limitations. As an
<dt>stop()</dt>
<dd>cancel any previously running alarm.</dd>
<dt>fired()</dt>
-<dd>signals that the alarm has occurred.</dd>
+<dd>signals that the alarm has expired.</dd>
<dt>isRunning()</dt>
<dd>return TRUE if the alarm has been started and has not been cancelled
or has not yet fired. FALSE is returned otherwise.</dd>
the TOSH_uwait macro from TinyOS 1.x.</p>
<p>BusyWait blocks for no less than the specified amount of time. No
explicit upper bound is imposed on the enacted delay, though it is
-expected the underlying implementation spins in a busy loop until
+expected that the underlying implementation spins in a busy loop until
the specified amount of time has elapsed.</p>
<pre class="literal-block">
interface BusyWait<precision_tag,size_type>
<dt>stop()</dt>
<dd>cancel any previously running timer.</dd>
<dt>fired()</dt>
-<dd>signals that the timer has occurred.</dd>
+<dd>signals that the timer has expired (one-shot) or repeated (periodic).</dd>
<dt>isRunning()</dt>
<dd>return TRUE if the timer has been started and has not been cancelled
-and has not fired for the case of one-shot timers. One a periodic
+and has not fired for the case of one-shot timers. Once a periodic
timer is started, isRunning will return TRUE until it is cancelled.</dd>
<dt>isOneShot()</dt>
<dd>return TRUE if the timer is a one-shot timer. Return FALSE
provides interface Alarm< T32khz, uint8_t >;
}
</pre>
-<p>This pattern MAY be used to defined components for the platform that
-are mutually incompatible in single application. Incompatible
+<p>This pattern MAY be used to define components for the platform that
+are mutually incompatible in a single application. Incompatible
components SHOULD produce compile-time errors when compiled
together.</p>
</div>
<li><tt class="docutils literal"><span class="pre">VirtualizeTimerC.nc</span></tt></li>
</ul>
</blockquote>
-<p>The implementation of Timers for the MSP430 is in
+<p>The implementation of timers for the MSP430 is in
<tt class="docutils literal"><span class="pre">tinyos-2.x/tos/chips/msp430/timer</span></tt>:</p>
<blockquote>
<ul class="simple">
special function registers</li>
</ul>
</blockquote>
+<p>Implementation of timers for the ATmega128 and PXA27x may be found in
+<tt class="docutils literal"><span class="pre">tinyos-2.x/tos/chips/atm128/timer</span></tt> and
+<tt class="docutils literal"><span class="pre">tinyos-2.x/tos/chips/pxa27x/timer</span></tt> respectively.</p>
</div>
<div class="section">
<h1><a id="author-s-address" name="author-s-address">7. Author's Address</a></h1>
projects / tinyos-2.x.git / blobdiff