lesson1.html

tinyos中文手册,是根据tinyos系统自带手册翻译过来的,虽然质量不好,但是对英文不强的人还是有用的

BlinkM.nc module</font></nobr></b></td>
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<p>Now let's look at the module <tt>BlinkM.nc</tt>: </p>
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      <td width="100%"><b>BlinkM.nc</b>
      <pre>module BlinkM {<br>&nbsp; provides {<br>&nbsp;&nbsp;&nbsp; interface StdControl;<br>&nbsp; }<br>&nbsp; uses {<br>&nbsp;&nbsp;&nbsp; interface Timer;<br>&nbsp;&nbsp;&nbsp; interface Leds;<br>&nbsp; }<br>}<br>// Continued below...</pre>
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<p>The first part of the code states that this is a module called <tt>BlinkM</tt>and
declares the interfaces it provides and uses.&nbsp; The <tt>BlinkM</tt>&nbsp;
module <b>provides</b> the<b> </b>interface <tt>StdControl</tt>.&nbsp;
This means that <tt>BlinkM</tt> implements the <tt>StdControl</tt>
interface.&nbsp; As explained above, this is necessary to get the Blink
component initialized and started.&nbsp; The BlinkM module also <b>uses</b>
two interfaces: <tt>Leds</tt> and <tt>Timer. </tt>This means that
BlinkM may call any command declared in the interfaces it uses and must
also implement any events declared in those interfaces. </p>
<p><tt>The Leds </tt>interface defines several commands like <tt>redOn()</tt>,<tt>redOff()</tt>,
and so forth, which turn the different LEDs (red, green, or yellow) on
the mote on and off. Because <tt>BlinkM</tt> uses the <tt>Leds</tt>
interface, it can invoke any of these commands. Keep in mind, however,
that <tt>Leds</tt> is just an interface: the implementation is
specified in the Blink.nc configuration file. </p>
<p><tt>Timer.nc</tt> is a little more interesting: </p>
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      <pre>interface Timer {<br>&nbsp; command result_t start(char type, uint32_t interval);<br>&nbsp; command result_t stop();<br>&nbsp; event result_t fired();<br>}</pre>
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<p>Here we see that <tt>Timer</tt> interface defines the <tt>start()</tt>
and <tt>stop()</tt> commands, and the <tt>fired() </tt>event. </p>
<p>The <tt>start()</tt> command is used to specify the type of the
timer and the interval at which the timer will expire. The unit of the
interval argument is millisecond. The valid types are <tt>TIMER_REPEAT</tt>
and <tt>TIMER_ONE_SHOT</tt>. A one-shot timer ends after the specified
interval, while a repeat timer goes on and on until it is stopped by
the <tt>stop() </tt>command. </p>
<p>How does an application know that its timer has expired? The answer
is when it receives an event. The <tt>Timer</tt> interface provides an
event: </p>
<pre>&nbsp; event result_t fired();</pre>
An <b>event</b> is a function that the implementation of an interface
will signal when a certain event takes place. In this case, the <tt>fired()</tt>
event is signaled when the specified interval has passed. This is an
example of a <b>bi-directional interface</b>: an interface not only
provides <b>commands</b> that can be called <i>by users</i> of the
interface, but also signals <b>events</b> that call handlers <i>in the
user</i>. Think of an event as a callback function that the
implementation of an interface will invoke. A module that <b>uses</b>
an interface <i>must implement the events</i> that this interface uses.
<p>Let's look at the rest of <tt>BlinkM.nc</tt> to see how this all
fits together: </p>
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      <td width="100%"><b>BlinkM.nc, continued</b>
      <pre>implementation {<br><br>&nbsp; command result_t StdControl.init() {<br>&nbsp;&nbsp;&nbsp; call Leds.init();<br>&nbsp;&nbsp;&nbsp; return SUCCESS;<br>&nbsp; }<br><br>&nbsp; command result_t StdControl.start() {<br>&nbsp;&nbsp;&nbsp; return call Timer.start(TIMER_REPEAT, 1000) ;<br>&nbsp; }<br><br>&nbsp; command result_t StdControl.stop() {<br>&nbsp;&nbsp;&nbsp; return call Timer.stop();<br>&nbsp; }<br><br>&nbsp; event result_t Timer.fired()<br>&nbsp; {<br>&nbsp;&nbsp;&nbsp; call Leds.redToggle();<br>&nbsp;&nbsp;&nbsp; return SUCCESS;<br>&nbsp; }<br>}</pre>
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<p>This is simple enough. As we see the <tt>BlinkM</tt> module
implements the <tt>StdControl.init()</tt>, <tt>StdControl.start()</tt>,
and <tt>StdControl.stop()</tt> commands, since it provides the <tt>StdControl</tt>
interface. It also implements the <tt>Timer.fired()</tt> event, which is
necessary since <tt>BlinkM</tt> must implement any event from an
interface it uses. </p>
<p>The <tt>init()</tt> command in the implemented <tt>StdControl </tt>interface
simply initializes the Leds subcomponent with the call to <tt>Leds.init()</tt>.
The <tt>start()</tt> command invokes <tt>Timer.start()</tt> to create a
repeat timer that expires every 1000 ms. <tt>stop()</tt> terminates the
timer. Each time <tt>Timer.fired()</tt> event is triggered, the <tt>Leds.redToggle()</tt>
toggles the red LED. </p>
<p>You can view a graphical representation of the component
relationships within an application. TinyOS source files include
metadata within comment blocks that ncc, the nesC compiler, uses to
automatically generate html-formatted documentation. To generate the
documentation, type <tt>make &lt;platform&gt; docs</tt> from the
application directory. The resulting documentation is located in <tt>docs/nesdoc/&lt;platform&gt;</tt>.<tt>docs/nesdoc/&lt;platform&gt;/index.html</tt>
is the main index to all documented applications. <br>
&nbsp;
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      <td width="100%"><b><nobr><font face="arial,helvetica">Compiling
the Blink application</font></nobr></b></td>
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<p>TinyOS supports multiple platforms. Each platform has its own
directory in the <a href="../../tos/platform">tos/platform</a>
directory. In this tutorial, we will use the mica platform as an
example. If you are in the TinyOS source tree, compiling the <tt>Blink</tt>
application for the Mica mote is as simple as typing </p>
<pre>&nbsp; make mica</pre>
in the <tt><a href="../../apps/Blink">apps/Blink</a></tt> directory. Of
course this doesn't tell you anything about how the nesC compiler is
invoked.
<p>nesC itself is invoked using the <a href="../nesc/ncc.html"><tt>ncc</tt></a>
command which is based on <tt>gcc</tt>. For example, you can type </p>
<pre>&nbsp; ncc -o main.exe -target=mica Blink.nc</pre>
to compile the <tt>Blink</tt> application (from the <tt>Blink.nc</tt>
top-level configuration) to <tt>main.exe</tt>, an executable file for
the Mica mote. Before you can upload the code to the mote, you use
<pre>&nbsp; avr-objcopy --output-target=srec main.exe main.srec</pre>
to produce <tt>main.srec</tt>, which essentially represents the binary <tt>main.exe</tt>
file in a text format that can be used for programming the mote. You
then use another tool (such as <tt>uisp</tt>) to actually upload the
code to the mote, depending on your environment. In general you will
never need to invoke <tt>ncc</tt> or <tt>avr-objcopy</tt> by hand, the
Makefile does all this for you, but it's nice to see that all you need
to compile a nesC application is to run <tt>ncc</tt> on the top-level
configuration file for your application. <tt>ncc</tt> takes care of
locating and compiling all of the different components required by your
application, linking them together, and ensuring that all of the
component wiring matches up. <br>
&nbsp; <br>
&nbsp;
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      <td width="100%"><b><nobr><font face="arial,helvetica">Programming
the mote and running Blink</font></nobr></b></td>
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<p>Now that we've compiled the application it's time to program the
mote and run it. This example will use the Mica mote and the
parallel-port-based programming board (<span
 style="font-family: monospace;">mib500</span>). Instructions on how to
use the other programming boards are <a href="programmers.html">here</a>.
To download your program onto the mote, place the mote board (or mote
and sensor stack) into the bay on the programming board, as shown
below. You can either supply a 3 volt supply to the connector on the
programming board or power the node directly. The red LED (labeled D2)
on the programming board will be on when power is supplied. If you are
using batteries to power the mote, be sure the mote is switched on (the
power switch should be towards the connector). </p>
<p>Plug the 32-pin connector into the parallel port of a computer
configured with the TinyOS tools, using a standard DB32 parallel port
cable. </p>
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      <td><img src="imgs/mica-offboard.jpg" height="240" width="320"></td>
      <td><img src="imgs/mica-onboard.jpg" height="240" width="320"></td>
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      <td><i>Mica mote next to the programming board</i></td>
      <td><i>Mica mote connected to the programming board</i></td>
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<p>Type: <tt>make mica install</tt>. If you get the error: </p>
<pre>&nbsp; uisp -dprog=dapa --erase&nbsp;<br>&nbsp; pulse<br>&nbsp; An error has occurred during the AVR initialization.<br>&nbsp;&nbsp; * Target status:<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Vendor Code = 0xff, Part Family = 0xff, Part Number = 0xff<br><br>&nbsp; Probably the wiring is incorrect or target might be `damaged'.<br>&nbsp; make: *** [install] Error 2</pre>
check whether the power is on. You can also get this error message if
the mote is low on batteries (if you are using batteries), or if the
wrong version of the <tt>uisp</tt> programming utility is installed (be
sure to use the version in the TinyOS distribution).
<p>If you are using an IBM ThinkPad, it may be necessary to tell the
tools to use a different parallel port. You can do this by adding the
line </p>
<pre>&nbsp; PROGRAMMER_EXTRA_FLAGS = -dlpt=3</pre>
to the <tt>apps/Makelocal</tt> file (create it if it doesn't exist). 
The <a href="buildenv.html"><tt>Makelocal</tt></a> file is for
user-specific <tt>Makefile</tt> configuration.
<p>If the installation is successful you should see something like the
following: </p>
<pre>&nbsp; compiling Blink to a mica binary<br>&nbsp; ncc -board=micasb -o build/mica/main.exe -Os -target=mica&nbsp; -Wall -Wshadow -DDEF_TOS_AM_GROUP=0x7d -finline-limit=200 -fnesc-cfile=build/mica/app.c&nbsp; Blink.nc -lm<br>&nbsp; avr-objcopy --output-target=srec build/mica/main.exe<br>&nbsp; build/mica/main.srec<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; compiled Blink to build/mica/main.srec<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; installing mica binary<br>&nbsp; uisp -dprog=dapa&nbsp; --erase&nbsp;<br>&nbsp; pulse<br>&nbsp; Atmel AVR ATmega128 is found.<br>&nbsp; Erasing device ...<br>&nbsp; pulse<br>&nbsp; Reinitializing device<br>&nbsp; Atmel AVR ATmega128 is found.<br>&nbsp; sleep 1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>&nbsp; uisp -dprog=dapa&nbsp; --upload if=build/mica/main.srec<br>&nbsp; pulse<br>&nbsp; Atmel AVR ATmega128 is found.<br>&nbsp; Uploading: flash<br>&nbsp; sleep 1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>&nbsp; uisp -dprog=dapa&nbsp; --verify if=build/mica/main.srec<br>&nbsp; pulse<br>&nbsp; Atmel AVR ATmega128 is found.<br>&nbsp; Verifying: flash</pre>
You can now test the program by unplugging the mote from the
programming board and turning on the power switch (if it's not already
on). With any luck the red LED should light up every second -
congratulations!
<p>Typing <tt>make clean</tt> in the <tt>Blink</tt> directory will
clean up the compiled binary files. </p>
<p>If you are still having errors, then you need to check your TinyOS
installation and check the Mica hardware. See <a href="verifyhw.html">System
and Hardware Verification</a> for details. <br>
&nbsp;
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      <td width="100%"><b><nobr><font face="arial,helvetica">Exercises</font></nobr></b></td>
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</p>
<p>To test your new-found TinyOS programming skills, try out the
following: </p>
<ul>
  <li> Modify <tt>Blink</tt> to display the lower three bits of a
counter in the LEDs.</li>
</ul>
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      <td width="100%"><b><nobr><font face="arial,helvetica">Conclusion</font></nobr></b></td>
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<p>This tutorial has just scratched the surface of nesC's syntax and
features. Rather than document everything extensively, we refer the
reader to the <a href="http://www.sourceforge.net/projects/nescc/">nesC
Project Pages</a> as well as the documentation included with the nesC
distribution in <tt>nesc/doc</tt>. These sources contain more complete
documentation on the language. </p>
<p>Hopefully this should be enough of a start to get you going on
programming in this fun new language. </p>
<p> </p>
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