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54 lines
2.6 KiB
54 lines
2.6 KiB
<script type="text/x-red" data-help-name="AudioOutputAnalog">
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<h3>Summary</h3>
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<div class=tooltipinfo>
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<p>Transmit 12 bit audio using Teensy's built-in digital to analog converter.</p>
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<p align=center><img src="img/dac_speaker.jpg"><br>
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<small><a href="http://www.pjrc.com/store/prop_shield.html" target="_blank_">Prop Shield with 4Ω Speaker</a></small></p>
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</div>
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<h3>Audio Connections</h3>
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<table class=doc align=center cellpadding=3>
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<tr class=top><th>Port</th><th>Purpose</th></tr>
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<tr class=odd><td align=center>In 0</td><td>Audio Channel</td></tr>
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</table>
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<h3>Functions</h3>
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<p class=func><span class=keyword>analogReference</span>(ref);</p>
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<p class=desc>Configure output voltage range:<br>
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<span class=literal>INTERNAL</span> selects 1.2 volt peak-to-peak output.<br>
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<span class=literal>EXTERNAL</span> selects 3.3 volt peak-to-peak output.
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</p>
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<h3>Hardware</h3>
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<p align=center><img src="img/dacpin.jpg"></p>
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<p>Signal range default is 0 to 1.2V</p>
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<p>The output voltage has DC level. Some applications require a DC-blocking capacitor. If unsure, a 10µF is usually a safe value to use. If an aluminum or tantalum capacitor is used, the positive terminal should connect to Teensy's DAC pin.</p>
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<p>The DAC pin is used with the
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<a href="http://www.pjrc.com/store/prop_shield.html" target="_blank_">Prop Shield</a>
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to drive speakers.</p>
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<h3>Examples</h3>
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<p class=exam>File > Examples > Audio > HardwareTesting > PassThroughMono
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</p>
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<p class=exam>File > Examples > Audio > SamplePlayer
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</p>
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<p class=exam><a href="https://github.com/PaulStoffregen/TouchGuitar" target="_blank">TouchGuitar</a>
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</p>
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<p class=exam><a href="https://community.arm.com/groups/embedded/blog/2014/05/23/led-video-panel-at-maker-faire-2014" target="_blank">LED Video Board</a>
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</p>
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<p class=exam>File > Examples > OctoWS2811 > VideoSDcard
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</p>
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<p class=exam>File > Examples > SerialFlash > MP3Player
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</p>
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<h3>Notes</h3>
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<p>The output rate is 44.1 kHz (no oversampling). Ultrasonic noise present if
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not filtered. This may not
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be an issue for many uses, but care should be used if amplified and driven
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to high power tweeters.</p>
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<p>When using 3.3V output, the power supply is used for the analog reference. Noise
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present on the 3.3V power can couple to the DAC output signal.
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</p>
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</script>
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<script type="text/x-red" data-template-name="AudioOutputAnalog">
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<div class="form-row">
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<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
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<input type="text" id="node-input-name" placeholder="Name">
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</div>
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</script>
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