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teensy-audio
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  1. <!DOCTYPE html>

  2. <!-- vim: set ts=4: -->

  3. <html>

  4. <meta charset="utf-8">

  5. <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=0"/>

  6. <meta name="apple-mobile-web-app-capable" content="yes">

  7. <meta name="mobile-web-app-capable" content="yes">

  8. 

  9. <!--

  10.   Modified from original Node-Red source, for audio system visualization

  11. 

  12.   Copyright 2013 IBM Corp.

  13. 

  14.   Licensed under the Apache License, Version 2.0 (the "License");

  15.   you may not use this file except in compliance with the License.

  16.   You may obtain a copy of the License at

  17. 

  18.   http://www.apache.org/licenses/LICENSE-2.0

  19. 

  20.   Unless required by applicable law or agreed to in writing, software

  21.   distributed under the License is distributed on an "AS IS" BASIS,

  22.   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  23.   See the License for the specific language governing permissions and

  24.   limitations under the License.

  25. -->

  26. <head>

  27. <title>Audio System Design Tool for Teensy Audio Library</title>

  28. <link href="bootstrap/css/bootstrap.min.css" rel="stylesheet" media="screen">

  29. <link href="jquery/css/smoothness/jquery-ui-1.10.3.custom.min.css" rel="stylesheet" media="screen">

  30. <link rel="stylesheet" type="text/css" href="orion/built-editor.css"/>

  31. <link rel="stylesheet" type="text/css" href="font-awesome/css/font-awesome.min.css"/>

  32. <link rel="stylesheet" href="style.css">

  33. <style>

  34. table.doc {border-spacing:3px; border-collapse:separate; font-size: 80%}

  35. tr.top {background-color:#C0C0C0}

  36. tr.odd {background-color:#F0F0F0}

  37. tr.even {background-color:#E0E0E0}

  38. p.func {padding-bottom:0; margin:0px}

  39. p.desc {padding-left:2em; margin:0px; padding-top:0.2em; padding-bottom:0.8em; font-size:0.75em}

  40. p.exam {padding-left:2em; text-indent:-1.2em; margin:0px; padding-top:0; padding-bottom:0.5em; font-size:0.75em; font-weight:bold}

  41. pre.desc {padding-left:3em; margin:0px; padding-top:0em; padding-bottom:0.8em; font-size:0.75em;

  42. 	background-color:#FFFFFF; border:0px; line-height:100%;

  43. }

  44. span.indent {padding-left:2em}

  45. span.literal {color: #006699}

  46. span.comment {color: #777755}

  47. span.keyword {color: #cc6600}

  48. span.function {color: #996600}

  49. span.mainfunction {color: #993300; font-weight: bolder}

  50. </style>

  51. </head>

  52. <body spellcheck="false">

  53. <div class="navbar navbar-inverse navbar-fixed-top">

  54. 	<div class="navbar-inner">

  55. 		<div class="container-fluid">

  56. 			<span class="brand">Audio System Design Tool for <a href="http://www.pjrc.com/teensy/td_libs_Audio.html" target="_blank">Teensy Audio Library</a></span>

  57. 			<div class="btn-group pull-right">

  58. 				<a class="btn dropdown-toggle" data-toggle="dropdown" href="#"><i class="icon-align-justify"></i> <span class="caret"></span></a>

  59. 				<ul class="dropdown-menu">

  60. 					<li><a id="btn-sidebar" tabindex="-1" href="#"><i class="icon-ok pull-right"></i><i class="icon-list-alt"></i> Sidebar</a></li>

  61. 					<li class="divider"></li>

  62. 					<!-- <li><a id="btn-node-status" tabindex="-1" href="#"><i class="icon-ok pull-right"></i><i class="icon-info-sign"></i> Node Status</a></li>

  63. 					<li class="divider"></li>

  64. -->

  65. 					<!--

  66. <li class="dropdown-submenu pull-left"><a tabindex="-1" href="#"><i class="icon-edit"></i> Import from...</a>

  67. 						<ul class="dropdown-menu">

  68. 							<li><a id="btn-import" tabindex="-1" href="#"><i class="icon-edit"></i> Clipboard...</a></li>

  69. 							<li id="flow-menu-parent" class="dropdown-submenu pull-left">

  70. 								<a tabindex="-1" href="#"><i class="icon-book"></i> Library</a>

  71. 								<ul class="dropdown-menu"></ul>

  72. 							</li>

  73. 						</ul>

  74. 					</li>

  75. 					<li id="li-menu-export" class="dropdown-submenu disabled pull-left"><a tabindex="-1" href="#"><i class="icon-share"></i> Export to...</a>

  76. 						<ul class="dropdown-menu">

  77. 							<li id="li-menu-export-clipboard" class="disabled"><a id="btn-export-clipboard" tabindex="-1" href="#"><i class="icon-share"></i> Clipboard...</a></li>

  78. 							<li id="li-menu-export-library" class="disabled"><a id="btn-export-library" tabindex="-1" href="#"><i class="icon-book"></i> Library...</a></li>

  79. 						</ul>

  80. 					</li>

  81. 					<li class="divider"></li>

  82. -->

  83. 					<!--

  84.  <li><a id="btn-config-nodes" tabindex="-1" href="#"><i class="icon-th-list"></i> Configuration nodes...</a></li>

  85. 					<li class="divider"></li>

  86. -->

  87. 					<!--

  88. <li class="dropdown-submenu pull-left"><a tabindex="-1" href="#"><i class="icon-th-large"></i> Workspaces</a>

  89. 						<ul id="workspace-menu-list" class="dropdown-menu">

  90. 							<li><a id="btn-workspace-add" tabindex="-1" href="#"><i class="icon-plus"></i> Add</a></li>

  91. 							<li><a id="btn-workspace-edit" tabindex="-1" href="#"><i class="icon-edit"></i> Rename</a></li>

  92. 							<li><a id="btn-workspace-delete" tabindex="-1" href="#"><i class="icon-minus"></i> Delete</a></li>

  93. 							<li class="divider"></li>

  94. 						</ul>

  95. 					</li>

  96. 					<li class="divider"></li>-->

  97. 					<li><a id="btn-keyboard-shortcuts" tabindex="-1" href="#"><i class="icon-question-sign"></i> Keyboard Shortcuts</a></li>

  98. 					<li><a id="btn-help" tabindex="-1" href="http://node-red.github.io/docs" target="_blank"><i class="icon-question-sign"></i> Help...</a></li>

  99. 				</ul>

  100. 			</div>

  101. 			<div class="btn-group pull-left">

  102. 				<a id="btn-deploy" class="btn action-deploy disabled" href="#"><i id="btn-icn-deploy" class="icon-upload"></i>Export</a>

  103. 				<a id="btn-import" class="btn action-import disabled" href="#"><i id="btn-icn-download" class="icon-download"></i>Import</a>

  104. 			</div>

  105. 		</div>

  106. 	</div>

  107. </div>

  108. <div id="main-container" class="sidebar-closed">

  109. 	<div id="palette">

  110. 		<img src="img/spin.svg" class="palette-spinner"/>

  111. 		<div id="palette-container" class="palette-scroll">

  112. 		</div>

  113. 		<div id="palette-search">

  114. 			<i class="icon-search"></i><input id="palette-search-input" type="text" placeholder="filter"><a href="#" id="palette-search-clear"><i class="icon-remove"></i></a></input>

  115. 		</div>

  116. 	</div><!-- /palette -->

  117. 

  118. 	<div id="workspace">

  119. 		<ul id="workspace-tabs"></ul>

  120. 		<!--<div id="workspace-add-tab"><a id="btn-workspace-add-tab" href="#"><i class="icon-plus"></i></a></div>-->

  121. 		<div id="chart"></div>

  122. 		<div id="workspace-toolbar">

  123. 			<div class="btn-group">

  124. 				<a class="btn btn-small" href="#"><i class="icon-zoom-out"></i></a>

  125. 				<a class="btn btn-small" href="#"><i class="icon-th"></i></a>

  126. 				<a class="btn btn-small" href="#"><i class="icon-zoom-in"></i></a>

  127. 			</div>

  128. 		</div>

  129. 	</div>

  130. 

  131. 	<div id="chart-zoom-controls">

  132. 		<div class="btn-group">

  133. 			<a class="btn btn-mini" id="btn-zoom-out" href="#"><i class="icon-zoom-out"></i></a>

  134. 			<a class="btn btn-mini" id="btn-zoom-zero" href="#"><i class="icon-th"></i></a>

  135. 			<a class="btn btn-mini" id="btn-zoom-in" href="#"><i class="icon-zoom-in"></i></a>

  136. 		</div>

  137. 	</div>

  138. 

  139. 	<div id="sidebar">

  140. 		<ul id="sidebar-tabs"></ul>

  141. 		<div id="sidebar-content"></div>

  142. 	</div>

  143. 

  144. 	<div id="sidebar-separator"></div>

  145. 

  146. </div>

  147. 

  148. <div id="notifications"></div>

  149. <div id="dropTarget"><div>Drop the flow here</div></div>

  150. 

  151. <div id="dialog" class="hide"><form id="dialog-form" class="form-horizontal"></form></div>

  152. <div id="node-config-dialog" class="hide"><form id="dialog-config-form" class="form-horizontal"></form><div class="form-tips" id="node-config-dialog-user-count"></div></div>

  153. 

  154. <div id="node-dialog-confirm-deploy" class="hide">

  155. 	<form class="form-horizontal">

  156. 		<div id="node-dialog-confirm-deploy-config" style="text-align: center; padding-top: 30px;">

  157. 		 Some of the nodes are not properly configured. Are you sure you want to deploy?

  158. 		</div>

  159. 		<div id="node-dialog-confirm-deploy-unknown" style="text-align: center; padding-top: 10px;">

  160. 		 The workspace contains some unknown node types:

  161. 		 <ul style="width: 300px; margin: auto; text-align: left;" id="node-dialog-confirm-deploy-unknown-list"></ul>

  162. 		 Are you sure you want to deploy?

  163. 		</div>

  164. 	</form>

  165. </div>

  166. 

  167. <div id="node-help" class="modal hide fade" tabindex="-1" role="dialog" aria-labelledby="node-help-label" aria-hidden="true">

  168.   <div class="modal-header">

  169. 	<h5 id="node-help-label">Keyboard Shortcuts <span style="float: right;"><a href="http://node-red.github.io/docs" target="_blank">Open help in new window &raquo;</a></span></h5>

  170.   </div>

  171.   <div class="modal-body">

  172. 	<table>

  173. 		<tr>

  174. 		  <td><span class="help-key">?</span></td><td>Help</td>

  175. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">a</span></td><td>Select all nodes</td>

  176. 		</tr>

  177. 		<tr>

  178. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">Space</span></td><td>Toggle sidebar</td>

  179. 		  <td><span class="help-key">Shift</span> <span class="help-key">Click</span></td><td>Select all connected nodes</td>

  180. 		</tr>

  181. 		<tr>

  182. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">z</span></td><td>Undo</td>

  183. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">Click</span></td><td>Add/remove node from selection</td>

  184. 		</tr>

  185. 		<tr>

  186. 		  <td></td><td></td>

  187. 		  <td><span class="help-key">Delete</span></td><td>Delete selected nodes or link</td>

  188. 		</tr>

  189. 		<tr>

  190. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">x</span></td><td>Cut selected nodes</td>

  191. 		  <td></td><td></td>

  192. 		</tr>

  193. 		<tr>

  194. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">c</span></td><td>Copy selected nodes</td>

  195. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">v</span></td><td>Paste nodes</td>

  196. 		</tr>

  197. 		<tr>

  198. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">i</span></td><td>Import nodes</td>

  199. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">e</span></td><td>Export selected nodes</td>

  200. 		</tr>

  201. 		<tr>

  202. 		  <td colspan="2"></td>

  203. 		</tr>

  204. 		<tr>

  205. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">+</span></td><td>Zoom in</td>

  206. 		  <td><span class="help-key">Ctrl</span> <span class="help-key">-</span></td><td>Zoom out</td>

  207. 		</tr>

  208. 	</table>

  209.   </div>

  210.   <div class="modal-footer">

  211. 	<button class="btn" data-dismiss="modal" aria-hidden="true">Close</button>

  212.   </div>

  213. </div>

  214. 

  215. <div id="node-dialog-library-save-confirm" class="hide">

  216. 	<form class="form-horizontal">

  217. 		<div style="text-align: center; padding-top: 30px;">

  218. 		 A <span id="node-dialog-library-save-type"></span> called <span id="node-dialog-library-save-name"></span> already exists. Overwrite?

  219. 		</div>

  220. 	</form>

  221. </div>

  222. 

  223. <div id="node-dialog-library-save" class="hide">

  224. 	<form class="form-horizontal">

  225. 		<div class="form-row">

  226. 			<label for="node-dialog-library-save-folder"><i class="icon-folder-open"></i> Folder</label>

  227. 			<input type="text" id="node-dialog-library-save-folder" placeholder="Folder">

  228. 		</div>

  229. 		<div class="form-row">

  230. 			<label for="node-dialog-library-save-filename"><i class="icon-file"></i> Filename</label>

  231. 			<input type="text" id="node-dialog-library-save-filename" placeholder="Filename">

  232. 		</div>

  233. 	</form>

  234. </div>

  235. 

  236. <div id="node-dialog-library-lookup" class="hide">

  237. 	<form class="form-horizontal">

  238. 		<div class="form-row">

  239. 			<ul id="node-dialog-library-breadcrumbs" class="breadcrumb">

  240. 				<li class="active"><a href="#">Library</a></li>

  241. 			</ul>

  242. 		</div>

  243. 		<div class="form-row">

  244. 			<div style="vertical-align: top; display: inline-block; height: 100%; width: 30%; padding-right: 20px;">

  245. 				<div id="node-select-library" style="border: 1px solid #999; width: 100%; height: 100%; overflow:scroll;"><ul></ul></div>

  246. 			</div>

  247. 			<div style="vertical-align: top; display: inline-block;width: 65%; height: 100%;">

  248. 				<div style="height: 100%; width: 95%;" class="node-text-editor" id="node-select-library-text" ></div>

  249. 			</div>

  250. 		</div>

  251. 	</form>

  252. </div>

  253. <div id="node-dialog-rename-workspace" class="hide">

  254. 	<form class="form-horizontal">

  255. 		<div class="form-row">

  256. 			<label for="node-input-workspace-name" ><i class="icon-tag"></i> Name:</label>

  257. 			<input type="text" id="node-input-workspace-name">

  258. 		</div>

  259. 	</form>

  260. </div>

  261. <div id="node-dialog-delete-workspace" class="hide">

  262. 	<form class="form-horizontal">

  263. 		<div style="text-align: center; padding-top: 30px;">

  264. 		 Are you sure you want to delete '<span id="node-dialog-delete-workspace-name"></span>'?

  265. 		</div>

  266. 	</form>

  267. </div>

  268. 

  269. <script type="text/x-red" data-template-name="export-clipboard-dialog">

  270. 	<div class="form-row">

  271. 		<label for="node-input-export" style="display: block; width:100%;"><i class="icon-share"></i> Source Code:</label>

  272. 		<textarea readonly style="font-family: monospace; font-size: 12px; background:rgb(226, 229, 255); padding-left: 0.5em;" class="input-block-level" id="node-input-export" rows="12"></textarea>

  273. 	</div>

  274. 	<div class="form-tips">

  275. 		Select the text above and copy to the clipboard with Ctrl-A Ctrl-C.

  276. 	</div>

  277. </script>

  278. <script type="text/x-red" data-template-name="export-library-dialog">

  279. 	<div class="form-row">

  280. 		<label for="node-input-filename" ><i class="icon-tag"></i> Filename:</label>

  281. 		<input type="text" id="node-input-filename" placeholder="Filename">

  282. 	</div>

  283. </script>

  284. <script type="text/x-red" data-template-name="import-dialog">

  285. 	<div class="form-row">

  286. 		<label for="node-input-import"><i class="icon-share"></i>Nodes:</label>

  287. 		<textarea style="font-family: monospace; font-size: 12px; background:rgb(226, 229, 255); padding-left: 0.5em;" class="input-block-level" id="node-input-import" rows="5" placeholder="Paste nodes here, or lookup in the library. When importing Arduino code, the whole flow will be replaced."></textarea>

  288. 	</div>

  289. 	<div class="form-tips">

  290. 		<label for="node-input-arduino" style="font-size: 13px; padding: 2px 0px 0px 4px;">

  291. 			<input style="margin-bottom: 4px; margin-right: 4px;" type="checkbox" id="node-input-arduino" checked="checked" class="input-block-level" />

  292. 				&nbsp;Import copied code from the Arduino IDE

  293. 		</label>

  294. 	</div>

  295. </script>

  296. 

  297. <script src="jquery/js/jquery-1.9.1.js"></script>

  298. <script src="bootstrap/js/bootstrap.min.js"></script>

  299. <script src="jquery/js/jquery-ui-1.10.3.custom.min.js"></script>

  300. <script src="jquery/js/jquery.ui.touch-punch.min.js"></script>

  301. <script src="orion/built-editor.min.js"></script>

  302. <script src="red/d3/d3.v3.min.js"></script>

  303. <script src="red/main.js"></script>

  304. <script src="red/ui/state.js"></script>

  305. <script src="red/nodes.js"></script>

  306. <script src="red/storage.js"></script>

  307. <script src="red/history.js"></script>

  308. <script src="red/ui/keyboard.js"></script>

  309. <script src="red/ui/tabs.js"></script>

  310. <script src="red/ui/view.js"></script>

  311. <script src="red/ui/sidebar.js"></script>

  312. <script src="red/ui/palette.js"></script>

  313. <script src="red/ui/tab-info.js"></script>

  314. <script src="red/ui/tab-config.js"></script>

  315. <script src="red/ui/editor.js"></script>

  316. <script src="red/ui/library.js"></script>

  317. <script src="red/ui/notifications.js"></script>

  318. <script src="red/ui/touch/radialMenu.js"></script>

  319. 

  320. <!--

  321.  TODO: generate some or all of this automatically from the C++ source

  322. -->

  323. 

  324. <!--

  325.  TODO: add a field for maximum instance count

  326. -->

  327. <!--

  328.  TODO: add a field for exclusive to other objects (not allowed if they're used)

  329. -->

  330. <!--

  331.  TODO: add "parameters" fields, to replace the form html stuff

  332. -->

  333. 

  334. <script type="text/x-red" data-help-name="AudioInputI2S">

  335. 	<h3>Summary</h3>

  336. 	<p>Receive 16 bit stereo audio from the

  337. 	<a href="http://www.pjrc.com/store/teensy3_audio.html" target="_blank">audio shield</a>

  338. 		or another I2S device, using I2S master mode.</p>

  339. 	<p align=center><img src="img/audioshield_inputs.jpg"></p>

  340. 	<h3>Audio Connections</h3>

  341. 	<table class=doc align=center cellpadding=3>

  342. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  343. 		<tr class=odd><td align=center>Out 0</td><td>Left Channel</td></tr>

  344. 		<tr class=odd><td align=center>Out 1</td><td>Right Channel</td></tr>

  345. 	</table>

  346. 	<h3>Functions</h3>

  347. 	<p>This object has no functions to call from the Arduino sketch.  It

  348. 		simply streams data from the I2S hardware to its 2 output ports.</p>

  349. 	<h3>Hardware</h3>

  350. 	<p align=center><img src="img/audioshield_backside.jpg"></p>

  351. 	<p>The I2S signals are used in "master" mode, where Teensy creates

  352. 		all 3 clock signals and controls all data timing.</p>

  353. 	<table class=doc align=center cellpadding=3>

  354. 		<tr class=top><th>Pin</th><th>Signal</th><th>Direction</th></tr>

  355. 		<tr class=odd><td align=center>9</td><td>BCLK</td><td>Output</td></tr>

  356. 		<tr class=odd><td align=center>11</td><td>MCLK</td><td>Output</td></tr>

  357. 		<tr class=odd><td align=center>13</td><td>RX</td><td>Input</td></tr>

  358. 		<tr class=odd><td align=center>23</td><td>LRCLK</td><td>Output</td></tr>

  359. 	</table>

  360. 	<p>Audio from

  361. 		master mode I2S may be used in the same project as ADC, DAC and

  362. 		PWM signals, because all remain in sync to Teensy's timing</p>

  363. 	<h3>Examples</h3>

  364. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; PassThroughStereo

  365. 	</p>

  366. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Recorder

  367. 	</p>

  368. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; PeakMeterStereo

  369. 	</p>

  370. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; FFT

  371. 	</p>

  372. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; SpectrumAnalyzerBasic

  373. 	</p>

  374. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Chorus

  375. 	</p>

  376. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Flange

  377. 	</p>

  378. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Filter

  379. 	</p>

  380. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Filter_FIR

  381. 	</p>

  382. 	<h3>Notes</h3>

  383. 	<p>Normally, this object is used with the Audio Shield, which

  384. 		is controlled separately by the "sgtl5000" object.</p>

  385. 	<p>Only one I2S input and one I2S output object may be used.  Master

  386. 		and slave modes may not be mixed (both must be of the same type).

  387. 	</p>

  388. 	<p>I2S master objects can be used together with non-I2S input and output

  389. 		objects, for simultaneous audio streaming on different hardware.</p>

  390. </script>

  391. <script type="text/x-red" data-template-name="AudioInputI2S">

  392. 	<div class="form-row">

  393. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  394. 		<input type="text" id="node-input-name" placeholder="Name">

  395. 	</div>

  396. </script>

  397. 

  398. <script type="text/x-red" data-help-name="AudioInputAnalog">

  399. 	<h3>Summary</h3>

  400. 	<p>Receive audio using the built-in analog to digital converter.</p>

  401. 	<h3>Audio Connections</h3>

  402. 	<table class=doc align=center cellpadding=3>

  403. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  404. 		<tr class=odd><td align=center>Out 0</td><td>Audio Channel</td></tr>

  405. 	</table>

  406. 	<h3>Functions</h3>

  407. 	<p>This object has no functions to call from the Arduino sketch.  It

  408. 		simply streams data from the ADC to its output port.</p>

  409. 	<h3>Hardware</h3>

  410. 	<p>Pin A2 is used for audio input.  This circuitry is recommended.</p>

  411. 	<p align=center><img src="img/adccircuit.png"></p>

  412. 	<p>Signal range is 0 to 1.2V</p>

  413. 	<h3>Examples</h3>

  414. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; PassThroughMono

  415. 	</p>

  416. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; PeakMeterMono

  417. 	</p>

  418. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; DialTone_7segment

  419. 	</p>

  420. 	<h3>Notes</h3>

  421. 	<p>A different pin may be used, but adding it as an parameter

  422. 		to the AudioInputAnalog object definition.

  423. 	</p>

  424. 	<p>For example, to use pin A3:

  425. 	</p>

  426. 	<p class=desc><span class=keyword>AudioInputAnalog</span>  adc1(<span class=literal>A3</span>);

  427. 	</p>

  428. 

  429. 	<p>Noise due to high source impedance, which allows rapidly switching digital signals

  430. 		to capacitively couple... avoiding higher analog impedance is the solution.</p>

  431. 	<p>Power Supply rejection issue with simple DC bias (bigger capacitor may be needed if 3.3V has low frequency noise)</p>

  432. 	<p>Algorithm for automatic DC bias tracking</p>

  433. 	<p>TODO: actual noise measurements with different input circuitry

  434. 		(it's not as quiet as the audio shield)</p>

  435. </script>

  436. <script type="text/x-red" data-template-name="AudioInputAnalog">

  437. 	<div class="form-row">

  438. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  439. 		<input type="text" id="node-input-name" placeholder="Name">

  440. 	</div>

  441. </script>

  442. 

  443. <script type="text/x-red" data-help-name="AudioInputI2Sslave">

  444. 	<h3>Summary</h3>

  445. 	<p>Receive 16 bit stereo audio from an I2S device using I2S slave mode.</p>

  446. 	<h3>Audio Connections</h3>

  447. 	<table class=doc align=center cellpadding=3>

  448. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  449. 		<tr class=odd><td align=center>Out 0</td><td>Left Channel</td></tr>

  450. 		<tr class=odd><td align=center>Out 1</td><td>Right Channel</td></tr>

  451. 	</table>

  452. 	<h3>Functions</h3>

  453. 	<p>This object has no functions to call from the Arduino sketch.  It

  454. 		simply streams data from the I2S hardware to its 2 output ports.</p>

  455. 	<h3>Hardware</h3>

  456. 	<p>The I2S signals are used in "slave" mode, where the I2S device controls

  457. 		data timing.</p>

  458. 	<table class=doc align=center cellpadding=3>

  459. 		<tr class=top><th>Pin</th><th>Signal</th><th>Direction</th></tr>

  460. 		<tr class=odd><td align=center>9</td><td>BCLK</td><td>Input</td></tr>

  461. 		<tr class=odd><td align=center>13</td><td>RX</td><td>Input</td></tr>

  462. 		<tr class=odd><td align=center>23</td><td>LRCLK</td><td>Input</td></tr>

  463. 	</table>

  464. 	<!--

  465. <h3>Examples</h3>

  466. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  467. 	</p>

  468. -->

  469. 	<h3>Notes</h3>

  470. 	<p>Slave mode I2S <b>should not used in the same project as ADC, DAC and

  471. 		PWM</b> signals.  Differences in timing between the I2S device and

  472. 		Teensy's clock can cause occasional audio glitches when I2S slave mode

  473. 		is used together with other input or output objects based on Teensy's

  474. 		timing.</p>

  475. 	<p>Only one I2S input and one I2S output object may be used.  Master

  476. 		and slave modes may not be mixed (both must be of the same type).

  477. 	</p>

  478. </script>

  479. <script type="text/x-red" data-template-name="AudioInputI2Sslave">

  480. 	<div class="form-row">

  481. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  482. 		<input type="text" id="node-input-name" placeholder="Name">

  483. 	</div>

  484. </script>

  485. 

  486. <script type="text/x-red" data-help-name="AudioOutputI2S">

  487. 	<h3>Summary</h3>

  488. 	<p>Transmit 16 bit stereo audio to the

  489. 	<a href="http://www.pjrc.com/store/teensy3_audio.html" target="_blank">audio shield</a>

  490. 		or another I2S device, using I2S master mode.</p>

  491. 	<p align=center><img src="img/audioshield_outputs.jpg"></p>

  492. 	<h3>Audio Connections</h3>

  493. 	<table class=doc align=center cellpadding=3>

  494. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  495. 		<tr class=odd><td align=center>In 0</td><td>Left Channel</td></tr>

  496. 		<tr class=odd><td align=center>In 1</td><td>Right Channel</td></tr>

  497. 	</table>

  498. 	<h3>Functions</h3>

  499. 	<p>This object has no functions to call from the Arduino sketch.  It

  500. 		simply streams data from its 2 input ports to the I2S hardware.</p>

  501. 	<h3>Hardware</h3>

  502. 	<p align=center><img src="img/audioshield_backside.jpg"></p>

  503. 	<p>The I2S signals are used in "master" mode, where Teensy creates

  504. 		all 3 clock signals and controls all data timing.</p>

  505. 	<table class=doc align=center cellpadding=3>

  506. 		<tr class=top><th>Pin</th><th>Signal</th><th>Direction</th></tr>

  507. 		<tr class=odd><td align=center>9</td><td>BCLK</td><td>Output</td></tr>

  508. 		<tr class=odd><td align=center>11</td><td>MCLK</td><td>Output</td></tr>

  509. 		<tr class=odd><td align=center>22</td><td>TX</td><td>Output</td></tr>

  510. 		<tr class=odd><td align=center>23</td><td>LRCLK</td><td>Output</td></tr>

  511. 	</table>

  512. 	<p>Audio from

  513. 		master mode I2S may be used in the same project as ADC, DAC and

  514. 		PWM signals, because all remain in sync to Teensy's timing</p>

  515. 	<h3>Examples</h3>

  516. 	<p>Nearly all the examples use this object.  Here are some of the highlights:</p>

  517. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; PassThroughStereo

  518. 	</p>

  519. 	<p class=exam>File &gt; Examples &gt; Audio &gt; SamplePlayer

  520. 	</p>

  521. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Recorder

  522. 	</p>

  523. 	<p class=exam>File &gt; Examples &gt; Audio &gt; WavFilePlayer

  524. 	</p>

  525. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Chorus

  526. 	</p>

  527. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Synthesis &gt; PlaySynthMusic

  528. 	</p>

  529. 	<h3>Notes</h3>

  530. 	<p>Normally, this object is used with the Audio Shield, which

  531. 		is controlled separately by the "sgtl5000" object.</p>

  532. 	<p>Only one I2S input and one I2S output object may be used.  Master

  533. 		and slave modes may not be mixed (both must be of the same type).

  534. 	</p>

  535. </script>

  536. <script type="text/x-red" data-template-name="AudioOutputI2S">

  537. 	<div class="form-row">

  538. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  539. 		<input type="text" id="node-input-name" placeholder="Name">

  540. 	</div>

  541. </script>

  542. 

  543. <script type="text/x-red" data-help-name="AudioOutputSPDIF">

  544. 	<h3>Summary</h3>

  545. 	<p>Transmit 16 bit stereo audio as Digital S/PDIF.</p>

  546. 	<p align=center><img src="img/spdif_proto.jpg"></p>

  547. 	<h3>Audio Connections</h3>

  548. 	<table class=doc align=center cellpadding=3>

  549. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  550. 		<tr class=odd><td align=center>In 0</td><td>Left Channel</td></tr>

  551. 		<tr class=odd><td align=center>In 1</td><td>Right Channel</td></tr>

  552. 	</table>

  553. 	<h3>Functions</h3>

  554. 	<p>This object has no functions to call from the Arduino sketch.  It

  555. 		simply streams data from its 2 input ports S/PDIF encoded digital

  556. 		audio on pin 22.</p>

  557. 	<h3>Hardware</h3>

  558. 	<p>The S/PDIF output signal can be used to drive an optical TOSLINK

  559. 		cable, or a standard (usually orange) RCA jack.</p>

  560. 	<table class=doc align=center cellpadding=3>

  561. 		<tr class=top><th>Pin</th><th>Signal</th><th>Direction</th></tr>

  562. 		<tr class=odd><td align=center>22</td><td>S/PDIF</td><td>Output</td></tr>

  563. 	</table>

  564. 	<p>For optical TOSLINK output, this

  565. 		<a href="https://www.oshpark.com/shared_projects/KcDBKHta" target="_blank">OSH Park board</a>

  566. 		can be used with the inexpensive Everlight PLT133/T6A connector, available

  567. 		at Digikey, 1080-1434-ND.

  568. 		</p>

  569. 	<h3>Examples</h3>

  570. 	<p>The AudioOutputSPDIF object can be used in place of the AudioOutputI2S object,

  571. 	<p>used in nearly all the examples.  The WavFilePlayer shows how to substitute

  572. 		output objects for different hardware types.

  573. 	</p>

  574. 	<p class=exam>File &gt; Examples &gt; Audio &gt; WavFilePlayer

  575. 	</p>

  576. 	<h3>Credits</h3>

  577. 	<p><a href="https://github.com/FrankBoesing" target="_blank">Frank Boesing</a>

  578. 		developed the AudioOutputSPDIF code.  The original

  579. 		<a href="https://forum.pjrc.com/threads/28639-S-pdif" target="_blank">forum disussion</a>

  580. 		included valuable input and code from "kpc".

  581. 	<h3>Notes</h3>

  582. 	<p>S/PDIF output uses the I2S hardware.  This object can not be used

  583. 		together with any of the I2S objects, because it requires the I2S

  584. 		hardware with different internal settings.</p>

  585. 	</p>

  586. </script>

  587. <script type="text/x-red" data-template-name="AudioOutputSPDIF">

  588. 	<div class="form-row">

  589. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  590. 		<input type="text" id="node-input-name" placeholder="Name">

  591. 	</div>

  592. </script>

  593. 

  594. <script type="text/x-red" data-help-name="AudioOutputAnalog">

  595. 	<h3>Summary</h3>

  596. 	<p>Transmit 12 bit audio using Teensy 3.1's built-in digital to analog converter.</p>

  597. 	<h3>Audio Connections</h3>

  598. 	<table class=doc align=center cellpadding=3>

  599. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  600. 		<tr class=odd><td align=center>In 0</td><td>Audio Channel</td></tr>

  601. 	</table>

  602. 	<h3>Functions</h3>

  603. 	<p>This object has no functions to call from the Arduino sketch.  It

  604. 		simply streams data from the ADC to its output port.</p>

  605. 	<h3>Hardware</h3>

  606. 	<p align=center><img src="img/dacpin.jpg"></p>

  607. 	<p>Signal range is 0 to 1.2V</p>

  608. 	<p>Most applications require at least a 10&micro;F DC-blocking capacitor.</p>

  609. 	<p>TODO: photo of Teensy 3.1 with 10&micro;F capacitor and 3.5mm jack.</p>

  610. 	<h3>Examples</h3>

  611. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; PassThroughMono

  612. 	</p>

  613. 	<p class=exam>File &gt; Examples &gt; Audio &gt; SamplePlayer

  614. 	</p>

  615. 	<h3>Notes</h3>

  616. 	<p>The output rate is 44.1 kHz (no oversampling).  Ultrasonic noise present if

  617. 		not filtered.  This may not

  618. 		be an issue for many uses, but care should be used if amplified and driven

  619. 		to high power tweeters.</p>

  620. </script>

  621. <script type="text/x-red" data-template-name="AudioOutputAnalog">

  622. 	<div class="form-row">

  623. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  624. 		<input type="text" id="node-input-name" placeholder="Name">

  625. 	</div>

  626. </script>

  627. 

  628. <script type="text/x-red" data-help-name="AudioOutputPWM">

  629. 	<h3>Summary</h3>

  630. 	<p>Transmit audio using Teensy 3.1's PWM pins.  Two pins are

  631. 		used for coarse and fine pulses, to be combined by scaled

  632. 		resistors.</p>

  633. 	<h3>Audio Connections</h3>

  634. 	<table class=doc align=center cellpadding=3>

  635. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  636. 		<tr class=odd><td align=center>In 0</td><td>Audio Channel</td></tr>

  637. 	</table>

  638. 	<h3>Functions</h3>

  639. 	<p>This object has no functions to call from the Arduino sketch.  It

  640. 		simply streams data from the its input port to the PWM pins.</p>

  641. 	<h3>Hardware</h3>

  642. 	<p>The following circuit is recommended.</p>

  643. 	<p align=center><img src="img/pwmdualcircuit.jpg"></p>

  644. 	<p>Signal range is approx 1.55 Vp-p.</p>

  645. 	<p>These resistor values assume approx 20 ohms output impedance

  646. 		on the digital pins.  The 127K resistor may be adjusted or

  647. 		trimmed for variation in output drive and tolerance on the

  648. 		475 ohm resistor.</p>

  649. 	<p>A plastic film (Polypropylene, Polyethylene, Polyester, etc) or

  650. 		C0G/NPO ceramic capacitor should be used for filtering.  Low

  651. 		quality ceramic (X7R, Y5V, Z5U, etc) can cause signal distortion.</p>

  652. 	<h3>Examples</h3>

  653. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; PassThroughMono

  654. 	</p>

  655. 	<h3>Notes</h3>

  656. 	<p>This object only works properly when Tools > CPU_Speed is set to

  657. 		48 or 96 MHz.  Other speeds aren't supported and will likely fail

  658. 		in strange ways.</p>

  659. 	<p>The PWM carrier frequency is 88.2 kHz.  The suggested circuit

  660. 		will only slightly filter the carrier.  Extra filtering will be

  661. 		required for a clean signal without the ultrasonic PWM carrier.

  662. 		</p>

  663. 	<p>Analog signals created by filtering PWM waveforms use the digital

  664. 		power supply as their reference voltage.  Any noise on the digital

  665. 		power line can directly couple to the output signal.  The built-in DAC or

  666. 		<a href="http://www.pjrc.com/store/teensy3_audio.html" target="_blank">audio shield</a>

  667. 		should be used when higher quality signals are needed.</p>

  668. </script>

  669. <script type="text/x-red" data-template-name="AudioOutputPWM">

  670. 	<div class="form-row">

  671. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  672. 		<input type="text" id="node-input-name" placeholder="Name">

  673. 	</div>

  674. </script>

  675. 

  676. <script type="text/x-red" data-help-name="AudioOutputI2Sslave">

  677. 	<h3>Summary</h3>

  678. 	<p>Transmit 16 bit stereo audio to an I2S device using I2S slave mode.</p>

  679. 	<h3>Audio Connections</h3>

  680. 	<table class=doc align=center cellpadding=3>

  681. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  682. 		<tr class=odd><td align=center>In 0</td><td>Left Channel</td></tr>

  683. 		<tr class=odd><td align=center>In 1</td><td>Right Channel</td></tr>

  684. 	</table>

  685. 	<h3>Functions</h3>

  686. 	<p>This object has no functions to call from the Arduino sketch.  It

  687. 		simply streams data from its 2 input ports to the I2S hardware.</p>

  688. 	<h3>Hardware</h3>

  689. 	<p>The I2S signals are used in "slave" mode, where the I2S device controls

  690. 		data timing.</p>

  691. 	<table class=doc align=center cellpadding=3>

  692. 		<tr class=top><th>Pin</th><th>Signal</th><th>Direction</th></tr>

  693. 		<tr class=odd><td align=center>9</td><td>BCLK</td><td>Input</td></tr>

  694. 		<tr class=odd><td align=center>22</td><td>TX</td><td>Output</td></tr>

  695. 		<tr class=odd><td align=center>23</td><td>LRCLK</td><td>Input</td></tr>

  696. 	</table>

  697. 	<h3>Examples</h3>

  698. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; WM8731MikroSine

  699. 	</p>

  700. 	<h3>Notes</h3>

  701. 	<p>Slave mode I2S <b>should not used in the same project as ADC, DAC and

  702. 		PWM</b> signals.  Differences in timing between the I2S device and

  703. 		Teensy's clock can cause occasional audio glitches when I2S slave mode

  704. 		is used together with other input or output objects based on Teensy's

  705. 		timing.</p>

  706. 	<p>Only one I2S input and one I2S output object may be used.  Master

  707. 		and slave modes may not be mixed (both must be of the same type).

  708. 	</p>

  709. </script>

  710. <script type="text/x-red" data-template-name="AudioOutputI2Sslave">

  711. 	<div class="form-row">

  712. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  713. 		<input type="text" id="node-input-name" placeholder="Name">

  714. 	</div>

  715. </script>

  716. 

  717. <script type="text/x-red" data-help-name="AudioMixer4">

  718. 	<h3>Summary</h3>

  719. 	<p>Combine up to 4 audio signals together, each with adjustable gain.

  720. 		All channels support signal attenuation or amplification.</p>

  721. 	<h3>Audio Connections</h3>

  722. 	<table class=doc align=center cellpadding=3>

  723. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  724. 		<tr class=odd><td align=center>In 0</td><td>Input signal #1</td></tr>

  725. 		<tr class=odd><td align=center>In 1</td><td>Input signal #2</td></tr>

  726. 		<tr class=odd><td align=center>In 2</td><td>Input signal #3</td></tr>

  727. 		<tr class=odd><td align=center>In 3</td><td>Input signal #4</td></tr>

  728. 		<tr class=odd><td align=center>Out 0</td><td>Sum of all inputs</td></tr>

  729. 	</table>

  730. 	<h3>Functions</h3>

  731. 	<p class=func><span class=keyword>gain</span>(channel, level);</p>

  732. 	<p class=desc>Adjust the amplification or attenuation.  "channel" must

  733. 		be 0 to 3.  "level" may be any floating point number from 0 to 32767.

  734. 		1.0 passes the signal through directly.  Level of 0 shuts the channel

  735. 		off completely.  Between 0 to 1.0 attenuates the signal, and above

  736. 		1.0 amplifies it.  All 4 channels have separate settings.

  737. 	</p>

  738. 	<h3>Examples</h3>

  739. 	<p class=exam>File &gt; Examples &gt; Audio &gt; SamplePlayer

  740. 	</p>

  741. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Synthesis &gt; PlaySynthMusic

  742. 	</p>

  743. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; SpectrumAnalyzerBasic

  744. 	</p>

  745. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; DialTone_Serial

  746. 	</p>

  747. 	<p class=exam>File &gt; Examples &gt; Audio &gt; MemoryAndCpuUsage

  748. 	</p>

  749. 	<h3>Notes</h3>

  750. 	<p>Signal clipping can occur when any channel has gain greater than 1.0,

  751. 		or when multiple signals add together to greater than 1.0.</p>

  752. 	<p>More than 4 channels may be combined by connecting multiple mixers

  753. 		in tandem.  For example, a 16 channel mixer may be built using 5

  754. 		mixers, where the fifth mixer combines the outputs of the first 4.

  755. 	</p>

  756. </script>

  757. <script type="text/x-red" data-template-name="AudioMixer4">

  758. 	<div class="form-row">

  759. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  760. 		<input type="text" id="node-input-name" placeholder="Name">

  761. 	</div>

  762. </script>

  763. 

  764. <script type="text/x-red" data-help-name="AudioPlayMemory">

  765. 	<h3>Summary</h3>

  766. 	<p>Play a short sound clip, stored directly in memory.

  767. 		Data files are created with the

  768. 		<a href="https://github.com/PaulStoffregen/Audio/tree/master/examples/SamplePlayer/wav2sketch" target="_blank">wav2sketch program</a>,

  769. 		and copied to the sketch folder to become part of your sketch.</p>

  770. 	<h3>Audio Connections</h3>

  771. 	<table class=doc align=center cellpadding=3>

  772. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  773. 		<tr class=odd><td align=center>Out 0</td><td>Sound Output</td></tr>

  774. 	</table>

  775. 	<h3>Functions</h3>

  776. 	<p class=func><span class=keyword>play</span>(data);</p>

  777. 	<p class=desc>Begin playing a sound clip.  If already playing, the

  778. 		currently playing clip is stopped and this new data begins

  779. 		playing from the beginning.

  780. 	</p>

  781. 	<p class=func><span class=keyword>stop</span>();</p>

  782. 	<p class=desc>Stop playing.  If not playing, this function has no effect.

  783. 	</p>

  784. 	<p class=func><span class=keyword>isPlaying</span>();</p>

  785. 	<p class=desc>Return true (non-zero) if playing, or false (zero)

  786. 		when not playing.

  787. 	</p>

  788. 	<p class=func><span class=keyword>positionMillis</span>();</p>

  789. 	<p class=desc>While playing, return the current time offset, in

  790. 		milliseconds.  When not playing, the return from this function

  791. 		is undefined.

  792. 	</p>

  793. 	<p class=func><span class=keyword>lengthMillis</span>();</p>

  794. 	<p class=desc>Return the total length of the current sound clip,

  795. 		in milliseconds.  When not playing, the return from this function

  796. 		is undefined.

  797. 	</p>

  798. 	<h3>Examples</h3>

  799. 	<p class=exam>File &gt; Examples &gt; Audio &gt; SamplePlayer

  800. 	</p>

  801. 	<h3>Notes</h3>

  802. 	<p>TODO: supported sample rates: 11.025, 22.05, 44.1</p>

  803. 	<p>TODO: ulaw vs uncompressed encoding</p>

  804. 	<p>Polyphonic playback can be built by creating multiple

  805. 		objects, with their output combined by mixers.</p>

  806. </script>

  807. <script type="text/x-red" data-template-name="AudioPlayMemory">

  808. 	<div class="form-row">

  809. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  810. 		<input type="text" id="node-input-name" placeholder="Name">

  811. 	</div>

  812. </script>

  813. 

  814. <script type="text/x-red" data-help-name="AudioPlaySdWav">

  815. 	<h3>Summary</h3>

  816. 	<p>Play a WAV file, stored on a SD card.</p>

  817. 	<h3>Audio Connections</h3>

  818. 	<table class=doc align=center cellpadding=3>

  819. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  820. 		<tr class=odd><td align=center>Out 0</td><td>Left Channel Output</td></tr>

  821. 		<tr class=odd><td align=center>Out 1</td><td>Right Channel Output</td></tr>

  822. 	</table>

  823. 	<h3>Functions</h3>

  824. 	<p class=func><span class=keyword>play</span>(filename);</p>

  825. 	<p class=desc>Begin playing a WAV file.  If a file is already playing,

  826. 		it is stopped and this file starts playing from the beginning.

  827. 	</p>

  828. 	<p class=func><span class=keyword>stop</span>();</p>

  829. 	<p class=desc>Stop playing.  If not playing, this function has no effect.

  830. 	</p>

  831. 	<p class=func><span class=keyword>isPlaying</span>();</p>

  832. 	<p class=desc>Return true (non-zero) if playing, or false (zero)

  833. 		when not playing.  See the note below about delayed start.

  834. 	</p>

  835. 	<p class=func><span class=keyword>positionMillis</span>();</p>

  836. 	<p class=desc>While playing, return the current time offset, in

  837. 		milliseconds.  When not playing, the return from this function

  838. 		is undefined.

  839. 	</p>

  840. 	<p class=func><span class=keyword>lengthMillis</span>();</p>

  841. 	<p class=desc>Return the total length of the current sound clip,

  842. 		in milliseconds.  When not playing, the return from this function

  843. 		is undefined.

  844. 	</p>

  845. 	<h3>Examples</h3>

  846. 	<p class=exam>File &gt; Examples &gt; Audio &gt; WavFilePlayer

  847. 	</p>

  848. 	<h3>Notes</h3>

  849. 	<p>Only 16 bit PCM, 44100 Hz WAV files are supported.  When mono

  850. 		files are played, both output ports transmit a copy of the

  851. 		single sound.  Of course, stereo WAV files play with the left

  852. 		channel on port 0 and the right channel on port 1.

  853. 	</p>

  854. 	<p>A brief delay after calling play() will usually occur before

  855. 		isPlaying() returns true and positionMillis() returns valid

  856. 		time offset.  WAV files have a header at the beginning of the

  857. 		file, which the audio library must read and parse before

  858. 		playing can begin.

  859. 	</p>

  860. 	<p>While playing, the audio library accesses the SD card automatically.

  861. 		If card access is required, you must

  862. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">use AudioNoInterrupts()</a>

  863. 		to prevent the library from accessing the SD card while you use it.

  864. 		Disabling the audio library interrupt for too long may cause audible

  865. 		dropouts or glitches.

  866. 	</p>

  867. </script>

  868. <script type="text/x-red" data-template-name="AudioPlaySdWav">

  869. 	<div class="form-row">

  870. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  871. 		<input type="text" id="node-input-name" placeholder="Name">

  872. 	</div>

  873. </script>

  874. 

  875. <script type="text/x-red" data-help-name="AudioPlaySdRaw">

  876. 	<h3>Summary</h3>

  877. 	<p>Play a RAW data file, stored on a SD card.  RAW format is simpler

  878. 		than WAV and begins playing immediately, without parsing WAV file

  879. 		header info.</p>

  880. 	<h3>Audio Connections</h3>

  881. 	<table class=doc align=center cellpadding=3>

  882. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  883. 		<tr class=odd><td align=center>Out 0</td><td>Sound Output</td></tr>

  884. 	</table>

  885. 	<h3>Functions</h3>

  886. 	<p class=func><span class=keyword>play</span>(filename);</p>

  887. 	<p class=desc>Begin playing a RAW data file.  If a file is already playing,

  888. 		it is stopped and this file starts playing from the beginning.

  889. 	</p>

  890. 	<p class=func><span class=keyword>stop</span>();</p>

  891. 	<p class=desc>Stop playing.  If not playing, this function has no effect.

  892. 	</p>

  893. 	<p class=func><span class=keyword>isPlaying</span>();</p>

  894. 	<p class=desc>Return true (non-zero) if playing, or false (zero)

  895. 		when not playing.

  896. 	</p>

  897. 	<p class=func><span class=keyword>positionMillis</span>();</p>

  898. 	<p class=desc>While playing, return the current time offset, in

  899. 		milliseconds.  When not playing, the return from this function

  900. 		is undefined.

  901. 	</p>

  902. 	<p class=func><span class=keyword>lengthMillis</span>();</p>

  903. 	<p class=desc>Return the total length of the current sound clip,

  904. 		in milliseconds.  When not playing, the return from this function

  905. 		is undefined.

  906. 	</p>

  907. 	<h3>Examples</h3>

  908. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Recorder

  909. 	</p>

  910. 	<h3>Notes</h3>

  911. 	<p>The data file must be RAW 16 bit signed integers in LSB-first format.

  912. 	</p>

  913. 	<p>While playing, the audio library accesses the SD card automatically.

  914. 		If card access is required, you must

  915. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">AudioNoInterrupts()</a>

  916. 		to prevent the library from accessing the SD card while you use it.

  917. 		Disabling the audio library interrupt for too long may cause audible

  918. 		dropouts or glitches.

  919. 	</p>

  920. </script>

  921. <script type="text/x-red" data-template-name="AudioPlaySdRaw">

  922. 	<div class="form-row">

  923. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  924. 		<input type="text" id="node-input-name" placeholder="Name">

  925. 	</div>

  926. </script>

  927. 

  928. <script type="text/x-red" data-help-name="AudioPlaySerialflashRaw">

  929. 	<h3>Summary</h3>

  930. 	<div>

  931. 	<p>Play a RAW data file, stored on a Serial Flash chip.  These chips

  932. 		are far more efficient than SD cards, allowing many files to be

  933. 		played simultaneously by copies of this object.

  934. 		</p>

  935. 	<p align=center><img src="img/w25q128fv.jpg"><br><small>W25Q128FV Serial Flash</small></p>

  936. 	</div>

  937. 	<h3>Audio Connections</h3>

  938. 	<table class=doc align=center cellpadding=3>

  939. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  940. 		<tr class=odd><td align=center>Out 0</td><td>Sound Output</td></tr>

  941. 	</table>

  942. 	<h3>Functions</h3>

  943. 	<p class=func><span class=keyword>play</span>(filename);</p>

  944. 	<p class=desc>Begin playing a RAW data file.  If a file is already playing,

  945. 		it is stopped and this file starts playing from the beginning.

  946. 	</p>

  947. 	<p class=func><span class=keyword>stop</span>();</p>

  948. 	<p class=desc>Stop playing.  If not playing, this function has no effect.

  949. 	</p>

  950. 	<p class=func><span class=keyword>isPlaying</span>();</p>

  951. 	<p class=desc>Return true (non-zero) if playing, or false (zero)

  952. 		when not playing.

  953. 	</p>

  954. 	<p class=func><span class=keyword>positionMillis</span>();</p>

  955. 	<p class=desc>While playing, return the current time offset, in

  956. 		milliseconds.  When not playing, the return from this function

  957. 		is undefined.

  958. 	</p>

  959. 	<p class=func><span class=keyword>lengthMillis</span>();</p>

  960. 	<p class=desc>Return the total length of the current sound clip,

  961. 		in milliseconds.  When not playing, the return from this function

  962. 		is undefined.

  963. 	</p>

  964. 	<h3>Examples</h3>

  965. 	<!--

  966. <p class=exam>File &gt; Examples &gt; Audio &gt; Recorder

  967. -->

  968. 	<p class=exam>TODO: play example needed....

  969. 	</p>

  970. 	<p class=exam>File &gt; Examples &gt; SerialFlash &gt; CopyFromSD

  971. 	</p>

  972. 	<h3>Notes</h3>

  973. 	<p>The data file must be RAW 16 bit signed integers in LSB-first format.

  974. 	</p>

  975. 	<p>The <a href="https://github.com/PaulStoffregen/SerialFlash" target="_blank">SerialFlash library</a>

  976. 		is used to access the flash chip.  You can also use SerialFlash's functions

  977. 		to access the stored files, or add data to the flash chip.

  978. 	</p>

  979. 	<p>File names are case sensitive with SerialFlash.  If your sound does

  980. 		not play, use <b>File &gt; Examples &gt; SerialFlash &gt; ListFiles</b> to

  981. 		check the exact file names stored in the flash memory chip.

  982. </script>

  983. <script type="text/x-red" data-template-name="AudioPlaySerialflashRaw">

  984. 	<div class="form-row">

  985. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  986. 		<input type="text" id="node-input-name" placeholder="Name">

  987. 	</div>

  988. </script>

  989. 

  990. <script type="text/x-red" data-help-name="AudioPlayQueue">

  991. 	<h3>Summary</h3>

  992. 	<p>Play audio data provided by the Arduino sketch.  This object provides

  993. 		functions to allow the sketch code to push data into the audio system.</p>

  994. 	<h3>Audio Connections</h3>

  995. 	<table class=doc align=center cellpadding=3>

  996. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  997. 		<tr class=odd><td align=center>Out 0</td><td>Sound Output</td></tr>

  998. 	</table>

  999. 	<h3>Functions</h3>

  1000. 	<p class=func><span class=keyword>play</span>(int16);</p>

  1001. 	<p class=desc>not yet implemented

  1002. 	</p>

  1003. 	<p class=func><span class=keyword>play</span>(int16[], length);</p>

  1004. 	<p class=desc>not yet implemented

  1005. 	</p>

  1006. 	<p class=func><span class=keyword>getBuffer</span>();</p>

  1007. 	<p class=desc>Returns a pointer to an array of 128 int16.  This buffer

  1008. 		is within the audio library memory pool, providing the most efficient

  1009. 		way to input data to the audio system.  The buffer is likely to be

  1010. 		populated by previously used data, so the entire 128 words should be

  1011. 		written before calling playBuffer().  Only a single buffer should be

  1012. 		requested at a time.  This function may return NULL if no memory is

  1013. 		available.

  1014. 	</p>

  1015. 	<p class=func><span class=keyword>playBuffer</span>();</p>

  1016. 	<p class=desc>Transmit the buffer previously obtained from getBuffer().

  1017. 	</p>

  1018. 	<h3>Examples</h3>

  1019. 		<p><a href="http://community.arm.com/groups/embedded/blog/2014/05/23/led-video-panel-at-maker-faire-2014" target="_blank">4320 LED Video+Sound Project</a>

  1020. 		</p>

  1021. 	<!--

  1022. <p class=exam>File &gt; Examples &gt; Audio &gt;

  1023. 	</p>

  1024. -->

  1025. 	<h3>Notes</h3>

  1026. 	<p>TODO: many caveats....</p>

  1027. 	<p>

  1028. 	</p>

  1029. </script>

  1030. <script type="text/x-red" data-template-name="AudioPlayQueue">

  1031. 	<div class="form-row">

  1032. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1033. 		<input type="text" id="node-input-name" placeholder="Name">

  1034. 	</div>

  1035. </script>

  1036. 

  1037. <script type="text/x-red" data-help-name="AudioRecordQueue">

  1038. 	<h3>Summary</h3>

  1039. 	<p>Record audio data by sending to the Arduino sketch.  This object allows

  1040. 		sketch code to receive audio packets.</p>

  1041. 	<h3>Audio Connections</h3>

  1042. 	<table class=doc align=center cellpadding=3>

  1043. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1044. 		<tr class=odd><td align=center>In 0</td><td>Sound To Access</td></tr>

  1045. 	</table>

  1046. 	<h3>Functions</h3>

  1047. 	<p class=func><span class=keyword>begin</span>();</p>

  1048. 	<p class=desc>Begin capturing incoming audio to the queue.  After calling

  1049. 		begin, readBuffer() and freeBuffer(), or clear() must be used frequently

  1050. 		to prevent the queue from filling up.

  1051. 	</p>

  1052. 	<p class=func><span class=keyword>available</span>();</p>

  1053. 	<p class=desc>Returns the number of audio packets available to read.

  1054. 	</p>

  1055. 	<p class=func><span class=keyword>readBuffer</span>();</p>

  1056. 	<p class=desc>Read a single audio packet.  A pointer to a 128 sample

  1057. 		array of 16 bit integers is returned.  NULL is returned if no packets

  1058. 		are available.

  1059. 	</p>

  1060. 	<p class=func><span class=keyword>freeBuffer</span>();</p>

  1061. 	<p class=desc>Release the memory from the previously read packet returned

  1062. 		from readBuffer().  Only a single packet at a time may be read, and

  1063. 		each packet must be freed with this function, to return the memory to

  1064. 		the audio library.

  1065. 	</p>

  1066. 	<p class=func><span class=keyword>clear</span>();</p>

  1067. 	<p class=desc>Discard all audio held in the queue.

  1068. 	</p>

  1069. 	<p class=func><span class=keyword>end</span>();</p>

  1070. 	<p class=desc>Stop capturing incoming audio into the queue.  Data already

  1071. 		captured remains in the queue and may be read with readBuffer().

  1072. 	</p>

  1073. 	<h3>Examples</h3>

  1074. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Recorder

  1075. 	</p>

  1076. 	<h3>Notes</h3>

  1077. 	<p>

  1078. 		Up to 52 packets may be queued by this object, which allows approximately

  1079. 		150 ms of audio to be held in the queue, to allow time for the Arduino

  1080. 		sketch to write data to media or do other high-latency tasks.

  1081. 

  1082. The actual packets are taken

  1083. 		from the pool created by AudioMemory().

  1084. 	</p>

  1085. </script>

  1086. <script type="text/x-red" data-template-name="AudioRecordQueue">

  1087. 	<div class="form-row">

  1088. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1089. 		<input type="text" id="node-input-name" placeholder="Name">

  1090. 	</div>

  1091. </script>

  1092. 

  1093. <script type="text/x-red" data-help-name="AudioSynthWaveformSine">

  1094. 	<h3>Summary</h3>

  1095. 	<p>Create a sine wave signal</p>

  1096. 	<h3>Audio Connections</h3>

  1097. 	<table class=doc align=center cellpadding=3>

  1098. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1099. 		<tr class=odd><td align=center>Out 0</td><td>Sine Wave Output</td></tr>

  1100. 	</table>

  1101. 	<h3>Functions</h3>

  1102. 	<p class=func><span class=keyword>amplitude</span>(level);</p>

  1103. 	<p class=desc>Set the amplitude, from 0 to 1.0.

  1104. 	</p>

  1105. 	<p class=func><span class=keyword>frequency</span>(freq);</p>

  1106. 	<p class=desc>Set the frequency, from 0 to 22000.  Very low values may

  1107. 		be used to create a LFO (Low Frequency Oscillator) for objects

  1108. 		with modulation signal inputs.

  1109. 	</p>

  1110. 	<p class=func><span class=keyword>phase</span>(angle);</p>

  1111. 	<p class=desc>

  1112. 		Cause the generated waveform to jump to a specific point within

  1113. 		its cycle.  Angle is from 0 to 360 degrees.  When multiple objects

  1114. 		are configured,

  1115. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">AudioNoInterrupts()</a>

  1116. 		should be used to guarantee all new settings take effect together.

  1117. 	</p>

  1118. 	<h3>Examples</h3>

  1119. 	<p class=exam>File &gt; Examples &gt; Audio &gt; MemoryAndCpuUsage

  1120. 	</p>

  1121. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; DialTone_Serial

  1122. 	</p>

  1123. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; FFT

  1124. 	</p>

  1125. 	<h3>Notes</h3>

  1126. 	<p></p>

  1127. </script>

  1128. <script type="text/x-red" data-template-name="AudioSynthWaveformSine">

  1129. 	<div class="form-row">

  1130. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1131. 		<input type="text" id="node-input-name" placeholder="Name">

  1132. 	</div>

  1133. </script>

  1134. 

  1135. <script type="text/x-red" data-help-name="AudioSynthWaveformSineModulated">

  1136. 	<h3>Summary</h3>

  1137. 	<p>Create a modulated sine wave, using any audio signal to continuously

  1138. 		modulate the sine wave frequency.</p>

  1139. 	<h3>Audio Connections</h3>

  1140. 	<table class=doc align=center cellpadding=3>

  1141. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1142. 		<tr class=odd><td align=center>In 0</td><td>Modulation Signal</td></tr>

  1143. 		<tr class=odd><td align=center>Out 0</td><td>Sine Wave Output</td></tr>

  1144. 	</table>

  1145. 	<h3>Functions</h3>

  1146. 	<p class=func><span class=keyword>amplitude</span>(level);</p>

  1147. 	<p class=desc>Set the amplitude, from 0 to 1.0.

  1148. 	</p>

  1149. 	<p class=func><span class=keyword>frequency</span>(freq);</p>

  1150. 	<p class=desc>Set the center frequency, from 0 to 11000.  The output will

  1151. 		be this center frequency when the input modulation signal is zero.

  1152. 		Modulation input 1.0 causes the frequency to double, and input -1.0

  1153. 		causes zero Hz (DC) output.  For less modulation, attenuate the input

  1154. 		signal (perhaps with a mixer object) before it arrives here.

  1155. 	</p>

  1156. 	<p class=func><span class=keyword>phase</span>(angle);</p>

  1157. 	<p class=desc>

  1158. 		Cause the generated waveform to jump to a specific point within

  1159. 		its cycle.  Angle is from 0 to 360 degrees.  When multiple objects

  1160. 		are configured,

  1161. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">AudioNoInterrupts()</a>

  1162. 		should be used to guarantee all new settings take effect together.

  1163. 	</p>

  1164. 	<!--

  1165. <h3>Examples</h3>

  1166. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  1167. 	</p>

  1168. -->

  1169. 	<h3>Notes</h3>

  1170. 	<p></p>

  1171. </script>

  1172. <script type="text/x-red" data-template-name="AudioSynthWaveformSineModulated">

  1173. 	<div class="form-row">

  1174. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1175. 		<input type="text" id="node-input-name" placeholder="Name">

  1176. 	</div>

  1177. </script>

  1178. 

  1179. <script type="text/x-red" data-help-name="AudioSynthWaveform">

  1180. 	<h3>Summary</h3>

  1181. 	<p>Create a waveform: sine, sawtooth, square, triangle, pulse or arbitrary.</p>

  1182. 	<h3>Audio Connections</h3>

  1183. 	<table class=doc align=center cellpadding=3>

  1184. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1185. 		<tr class=odd><td align=center>Out 0</td><td>Waveform Output</td></tr>

  1186. 	</table>

  1187. 	<h3>Functions</h3>

  1188. 	<p class=func><span class=keyword>begin</span>(waveform);</p>

  1189. 	<p class=desc>Configure the waveform type to create.

  1190. 	</p>

  1191. 	<p class=func><span class=keyword>begin</span>(level, frequency, waveform);</p>

  1192. 	<p class=desc>Output a waveform, and set the amplitude and frequency.

  1193. 	</p>

  1194. 	<p class=func><span class=keyword>frequency</span>(freq);</p>

  1195. 	<p class=desc>Change the frequency.

  1196. 	</p>

  1197. 	<p class=func><span class=keyword>amplitude</span>(level);</p>

  1198. 	<p class=desc>Change the amplitude.  Set to 0 to turn the signal off.

  1199. 	</p>

  1200. 	<p class=func><span class=keyword>phase</span>(angle);</p>

  1201. 	<p class=desc>

  1202. 		Cause the generated waveform to jump to a specific point within

  1203. 		its cycle.  Angle is from 0 to 360 degrees.  When multiple objects

  1204. 		are configured,

  1205. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">AudioNoInterrupts()</a>

  1206. 		should be used to guarantee all new settings take effect together.

  1207. 	</p>

  1208. 	<p class=func><span class=keyword>pulseWidth</span>(amount);</p>

  1209. 	<p class=desc>Change the width (duty cycle) of the pulse.</p>

  1210. 	<p class=func><span class=keyword>arbitraryWaveform</span>(array, maxFreq);</p>

  1211. 	<p class=desc>

  1212. 		Configure the waveform to be used with WAVEFORM_ARBITRARY.  Array

  1213. 		must be an array of 256 samples.  Currently, the data is used

  1214. 		without any filtering, which can cause aliasing with frequencies

  1215. 		above 172 Hz.  For higher frequency output, you must bandwidth

  1216. 		limit your waveform data.  Someday, "maxFreq" will be used to

  1217. 		do this automatically.

  1218. 	</p>

  1219. 	<h3>Examples</h3>

  1220. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Synthesis &gt; PlaySynthMusic

  1221. 	</p>

  1222. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Synthesis &gt; pulseWidth

  1223. 	</p>

  1224. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; WM8731MikroSine

  1225. 	</p>

  1226. 	<h3>Notes</h3>

  1227. 	<p>Supported Waveforms:<br>

  1228. 		<ul>

  1229. 		<li><span class=literal>WAVEFORM_SINE</span></li>

  1230. 		<li><span class=literal>WAVEFORM_SAWTOOTH</span></li>

  1231. 		<li><span class=literal>WAVEFORM_SQUARE</span></li>

  1232. 		<li><span class=literal>WAVEFORM_TRIANGLE</span></li>

  1233. 		<li><span class=literal>WAVEFORM_ARBITRARY</span></li>

  1234. 		<li><span class=literal>WAVEFORM_PULSE</span></li>

  1235. 		</ul>

  1236. 	</p>

  1237. </script>

  1238. <script type="text/x-red" data-template-name="AudioSynthWaveform">

  1239. 	<div class="form-row">

  1240. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1241. 		<input type="text" id="node-input-name" placeholder="Name">

  1242. 	</div>

  1243. </script>

  1244. 

  1245. <script type="text/x-red" data-help-name="AudioSynthToneSweep">

  1246. 	<h3>Summary</h3>

  1247. 	<p>Create a continuously varying (in frequency) sine wave</p>

  1248. 	<h3>Audio Connections</h3>

  1249. 	<table class=doc align=center cellpadding=3>

  1250. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1251. 		<tr class=odd><td align=center>Out 0</td><td>Continuously varying tone</td></tr>

  1252. 	</table>

  1253. 	<h3>Functions</h3>

  1254. 	<p class=func><span class=keyword>play</span>(level, lowFreq, highFreq, time);</p>

  1255. 	<p class=desc>Start generating frequency sweep output.  The time is specified

  1256. 		in milliseconds.  Level is 0 to 1.0.

  1257. 	</p>

  1258. 	<p class=func><span class=keyword>isPlaying</span>();</p>

  1259. 	<p class=desc>Returns true (non-zero) while the output is active.

  1260. 	</p>

  1261. 	<h3>Examples</h3>

  1262. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; ToneSweep

  1263. 	</p>

  1264. 	<h3>Notes</h3>

  1265. 	<p>Uses excessive CPU time</p>

  1266. </script>

  1267. <script type="text/x-red" data-template-name="AudioSynthToneSweep">

  1268. 	<div class="form-row">

  1269. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1270. 		<input type="text" id="node-input-name" placeholder="Name">

  1271. 	</div>

  1272. </script>

  1273. 

  1274. <script type="text/x-red" data-help-name="AudioSynthWaveformDc">

  1275. 	<h3>Summary</h3>

  1276. 	<p>Create constant (DC) signal, useful for control of objects that take

  1277. 		a modulation or control input signal.  This constant level can be

  1278. 		used to modify other waveforms using mixer or multiplier objects</p>

  1279. 	<h3>Audio Connections</h3>

  1280. 	<table class=doc align=center cellpadding=3>

  1281. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1282. 		<tr class=odd><td align=center>Out 0</td><td>Output constant DC level</td></tr>

  1283. 	</table>

  1284. 	<h3>Functions</h3>

  1285. 	<p class=func><span class=keyword>amplitude</span>(level);</p>

  1286. 	<p class=desc>Set the output.  Level is -1.0 to 1.0.  The output is

  1287. 		changed immediately.

  1288. 	</p>

  1289. 	<p class=func><span class=keyword>amplitude</span>(level, milliseconds);</p>

  1290. 	<p class=desc>Set the output.  Level is -1.0 to 1.0.  The output is

  1291. 		gradually changed over a "milliseconds" time period.  Any time may

  1292. 		be specified, but periods longer than 1 second may be automatically

  1293. 		shortened for small level changes, due to numerical precision limits.

  1294. 	</p>

  1295. 	<!--

  1296. <h3>Examples</h3>

  1297. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  1298. 	</p>

  1299. -->

  1300. 	<h3>Notes</h3>

  1301. 	<p>Of course, the term "DC", for Direct Current, doesn't properly apply

  1302. 		to a pure digital stream of numerical values.  But the term is widely

  1303. 		understood in audio applications, so hopefully it's not too confusing?</p>

  1304. </script>

  1305. <script type="text/x-red" data-template-name="AudioSynthWaveformDc">

  1306. 	<div class="form-row">

  1307. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1308. 		<input type="text" id="node-input-name" placeholder="Name">

  1309. 	</div>

  1310. </script>

  1311. 

  1312. <script type="text/x-red" data-help-name="AudioSynthNoiseWhite">

  1313. 	<h3>Summary</h3>

  1314. 	<div>

  1315. 	<p>Create white noise.

  1316. 		</p>

  1317. 	<p align=center><img src="img/whitenoise.png"></p>

  1318. 	</div>

  1319. 	<h3>Audio Connections</h3>

  1320. 	<table class=doc align=center cellpadding=3>

  1321. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1322. 		<tr class=odd><td align=center>Out 0</td><td>White Noise</td></tr>

  1323. 	</table>

  1324. 	<h3>Functions</h3>

  1325. 	<p class=func><span class=keyword>amplitude</span>(level);</p>

  1326. 	<p class=desc>Set the output peak level, from 0 (off) to 1.0.

  1327. 		The default is off.  Noise is generated only after setting

  1328. 		to a non-zero level.

  1329. 	</p>

  1330. 	<h3>Examples</h3>

  1331. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  1332. 	</p>

  1333. 	<h3>Notes</h3>

  1334. 	<p>Setting the amplitude to zero causes this object to stop using

  1335. 		CPU time to generate random numbers.

  1336. 	</p>

  1337. </script>

  1338. <script type="text/x-red" data-template-name="AudioSynthNoiseWhite">

  1339. 	<div class="form-row">

  1340. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1341. 		<input type="text" id="node-input-name" placeholder="Name">

  1342. 	</div>

  1343. </script>

  1344. 

  1345. <script type="text/x-red" data-help-name="AudioSynthNoisePink">

  1346. 	<h3>Summary</h3>

  1347. 	<div>

  1348. 	<p>Create pink noise, using Stefan Stenzel's "New Shade Of Pink" algorithm.

  1349. 		</p>

  1350. 	<!--

  1351. <p align=center><img src="img/whitenoise.png"></p>

  1352. -->

  1353. 	</div>

  1354. 	<h3>Audio Connections</h3>

  1355. 	<table class=doc align=center cellpadding=3>

  1356. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1357. 		<tr class=odd><td align=center>Out 0</td><td>Pink Noise</td></tr>

  1358. 	</table>

  1359. 	<h3>Functions</h3>

  1360. 	<p class=func><span class=keyword>amplitude</span>(level);</p>

  1361. 	<p class=desc>Set the output peak level, from 0 (off) to 1.0.

  1362. 		The default is off.  Noise is generated only after setting

  1363. 		to a non-zero level.

  1364. 	</p>

  1365. 	<h3>Examples</h3>

  1366. 	<p class=exam>File &gt; Examples &gt; Audio &gt; MemoryAndCpuUsage

  1367. 	</p>

  1368. 	<h3>Notes</h3>

  1369. 	<p>Setting the amplitude to zero causes this object to stop using

  1370. 		CPU time.  CPU usage is approx 3% on Teensy 3.1.

  1371. 	</p>

  1372. 	<p>Stefan Stenzel's

  1373. 		<a href="http://stenzel.waldorfmusic.de/post/pink/" target="_blank">New Shade Of Pink</a>

  1374. 		algorithm.  Stefan's terms of use are "Use for any purpose. If used

  1375. 		in a commercial product, you should give me one."

  1376. 	</p>

  1377. </script>

  1378. <script type="text/x-red" data-template-name="AudioSynthNoisePink">

  1379. 	<div class="form-row">

  1380. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1381. 		<input type="text" id="node-input-name" placeholder="Name">

  1382. 	</div>

  1383. </script>

  1384. 

  1385. <script type="text/x-red" data-help-name="AudioEffectFade">

  1386. 	<h3>Summary</h3>

  1387. 	<p>Gradually increase or decrease audio level.</p>

  1388. 	<h3>Audio Connections</h3>

  1389. 	<table class=doc align=center cellpadding=3>

  1390. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1391. 		<tr class=odd><td align=center>In 0</td><td>Signal Input</td></tr>

  1392. 		<tr class=odd><td align=center>Out 0</td><td>Signal Output</td></tr>

  1393. 	</table>

  1394. 	<h3>Functions</h3>

  1395. 	<p class=func><span class=keyword>fadeIn</span>(milliseconds);</p>

  1396. 	<p class=desc>Begin increasing the audio level, to reach 1.0 (input passed

  1397. 		directly to the output) after "milliseconds" time.

  1398. 	</p>

  1399. 	<p class=func><span class=keyword>fadeOut</span>(milliseconds);</p>

  1400. 	<p class=desc>Begin decreasing the audio level, to reach 0 (no output)

  1401. 		after "milliseconds" time.

  1402. 	</p>

  1403. 	<!--

  1404. <h3>Examples</h3>

  1405. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  1406. 	</p>

  1407. -->

  1408. 	<h3>Notes</h3>

  1409. 	<p>Cross fading can be built with 2 fade objects fed into a mixer.

  1410. 		When one fade object is off (fully faded out) and the other on

  1411. 		(fully faded in), if both are started at the same moment for the

  1412. 		same time duration, their signal gains always add to 1.0.  This

  1413. 		allows 2 fade objects to work together for a smooth transition

  1414. 		between a pair of signals.

  1415. 	</p>

  1416. 	<p><a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">AudioNoInterrupts()</a>

  1417. 		should be used when changing

  1418. 		settings on multiple objects, so all changes always take effect

  1419. 		at the same moment.

  1420. 	</p>

  1421. </script>

  1422. <script type="text/x-red" data-template-name="AudioEffectFade">

  1423. 	<div class="form-row">

  1424. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1425. 		<input type="text" id="node-input-name" placeholder="Name">

  1426. 	</div>

  1427. </script>

  1428. 

  1429. <script type="text/x-red" data-help-name="AudioEffectChorus">

  1430. <h3>Summary</h3>

  1431. 	<p>The chorus effect simulates the richness of several nearly-identical

  1432. 	sound sources (like the way a choir sounds different to a single singer).

  1433. 	It does this by sampling from a delay line, so each voice is actually

  1434. 	the same but at a slightly different point in time. This is a type of

  1435. 	comb filtering.</p>

  1436. 	<p>Chorus combines one or more samples ranging from the most recent

  1437. 	sample back to about 50ms ago. The additional samples are evenly spread

  1438. 	through the supplied delay line, and there is no modulation.</p>

  1439. 	<p>If the number of voices is specified as 2, then the

  1440. 	effect combines the current sample and the oldest sample (the last one

  1441. 	in the delay line). If the number of voices is 3 then the effect combines

  1442. 	the most recent sample, the oldest sample and the sample in the middle of

  1443. 	the delay line.</p>

  1444. 	<p>For two voices the effect can be represented as:<br/>

  1445. 	result = (sample(0) + sample(dt))/2<br/>

  1446. 	where sample(0) represents the current sample and sample(dt)

  1447. 	is the sample in the delay line from dt milliseconds ago.</p>

  1448. 	<h3>Audio Connections</h3>

  1449. 	<table class=doc align=center cellpadding=3>

  1450. 		<tr class="top"><th>Port</th><th>Purpose</th></tr>

  1451. 		<tr class="odd"><td align="center">In 0</td><td>Signal Input</td></tr>

  1452. 		<tr class="odd"><td align="center">Out 0</td><td>Chorused Output</td></tr>

  1453. 	</table>

  1454. 	<h3>Functions</h3>

  1455. 	<p class=func><span class=keyword>begin</span>(delayBuffer, length, n_chorus);</p>

  1456. 	<p class=desc>Create a chorus by specifying the address of the delayline, the

  1457. 	total number of samples in the delay line (often done as an integer multiple of

  1458. 	AUDIO_BLOCK_SAMPLES) and the number of voices in the chorus <em>including</em>

  1459. 	the original voice (so, 2 and up to get a chorus effect, although you can

  1460. 	specify 1 if you want).

  1461. 	</p>

  1462. 	<p class=func><span class=keyword>modify</span>(n_chorus);</p>

  1463. 	<p class=desc>Alters the number of voices in a running chorus (previously started with begin).

  1464. 	</p>

  1465. 	<h3>Examples</h3>

  1466. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Chorus

  1467. 	</p>

  1468. 	<h3>Notes</h3>

  1469. 	<p>The longer the length of the chorus, the more memory blocks are used.</p>

  1470. </script>

  1471. <script type="text/x-red" data-template-name="AudioEffectChorus">

  1472. 	<div class="form-row">

  1473. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1474. 		<input type="text" id="node-input-name" placeholder="Name">

  1475. 	</div>

  1476. </script>

  1477. 

  1478. <script type="text/x-red" data-help-name="AudioEffectFlange">

  1479. <h3>Summary</h3>

  1480. 	<p>Originally, flanging was produced by playing the same signal on two synchronized

  1481. 	reel-to-reel tape recorders and making one of the reels slow down and speed up by

  1482. 	pressing on the flange of the reel (hence the name). This is a type of

  1483. 	comb filtering, and produces a harmonically-related series of peaks and notches

  1484. 	in the audio spectrum.</p>

  1485. 	<p>This flanger uses a delay line, combining the original voice with only one sample from the delay

  1486. 	line, but the position of that sample varies sinusoidally.</p>

  1487. 	<p>The effect can be represented as:<br>

  1488. 	result = sample(0) + sample(dt + depth*sin(2*PI*Fe))</p>

  1489. 	<p>The value of the sine function is always a number from -1 to +1 and

  1490. 	so the result of depth*(sin(Fe)) is always a number from -depth to +depth.

  1491. 	Thus, the delayed sample will be selected from the range (dt-depth) to

  1492. 	(dt+depth). This selection will vary at whatever rate is specified as the

  1493. 	frequency of the effect, Fe. Typically a low frequency (a few Hertz) is used.

  1494. 	<h3>Audio Connections</h3>

  1495. 	<table class=doc align=center cellpadding=3>

  1496. 		<tr class="top"><th>Port</th><th>Purpose</th></tr>

  1497. 		<tr class="odd"><td align="center">In 0</td><td>Signal Input</td></tr>

  1498. 		<tr class="odd"><td align="center">Out 0</td><td>Flanged Output</td></tr>

  1499. 	</table>

  1500. 	<h3>Functions</h3>

  1501. 	<p class=func><span class=keyword>begin</span>(delayBuffer, length, offset, depth, delayRate);</p>

  1502. 	<p class=desc>Create a flanger by specifying the address of the delayline, the

  1503. 	total number of samples in the delay line (often done as an integer multiple of

  1504. 	AUDIO_BLOCK_SAMPLES), the offset (how far back the flanged sample is from the original voice),

  1505. 	the modulation depth (larger values give a greater variation) and the modulation

  1506. 	frequency, in Hertz.

  1507. 	</p>

  1508. 	<p class=func><span class=keyword>modify</span>(offset, depth, delayRate);</p>

  1509. 	<p class=desc>Alters the parameters in a running flanger (previously started with begin).

  1510. 	</p>

  1511. 

  1512. 	<h3>Examples</h3>

  1513. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Flange

  1514. 	</p>

  1515. 	<h3>Notes</h3>

  1516. 	<p>The longer the length of the delay buffer, the more memory blocks are used.</p>

  1517. 	<p>Try these settings:<br>

  1518. #define FLANGE_DELAY_LENGTH (2*AUDIO_BLOCK_SAMPLES)<br>

  1519. and<br>

  1520. int s_idx = 2*FLANGE_DELAY_LENGTH/4;<br>

  1521. int s_depth = FLANGE_DELAY_LENGTH/4;<br>

  1522. double s_freq = 3;</p>

  1523. <p>The flange effect can also produce a chorus-like effect if a longer

  1524. delay line is used with a slower modulation rate, for example try:<br>

  1525. #define FLANGE_DELAY_LENGTH (12*AUDIO_BLOCK_SAMPLES)<br>

  1526. and<br>

  1527. int s_idx = 3*FLANGE_DELAY_LENGTH/4;<br>

  1528. int s_depth = FLANGE_DELAY_LENGTH/8;<br>

  1529. double s_freq = .0625;</p>

  1530. </script>

  1531. <script type="text/x-red" data-template-name="AudioEffectFlange">

  1532. 	<div class="form-row">

  1533. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1534. 		<input type="text" id="node-input-name" placeholder="Name">

  1535. 	</div>

  1536. </script>

  1537. 

  1538. <script type="text/x-red" data-help-name="AudioEffectEnvelope">

  1539. 	<h3>Summary</h3>

  1540. 	<div>

  1541. 	<p>Modify a signal with a DAHDSR (Delay Attack Hold Decay Sustain

  1542. 		Release) envelope.

  1543. 	</p>

  1544. 	<p align=center><img src="img/dahdsr.png"></p>

  1545. 	</div>

  1546. 	<h3>Audio Connections</h3>

  1547. 	<table class=doc align=center cellpadding=3>

  1548. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1549. 		<tr class=odd><td align=center>In 0</td><td>Signal Input</td></tr>

  1550. 		<tr class=odd><td align=center>Out 0</td><td>Signal with Envelope Applied</td></tr>

  1551. 	</table>

  1552. 	<h3>Functions</h3>

  1553. 	<p class=func><span class=keyword>noteOn</span>();</p>

  1554. 	<p class=desc>Begin the delay to attack, or the attack phase is

  1555. 		delay is zero.

  1556. 	</p>

  1557. 	<p class=func><span class=keyword>noteOff</span>();</p>

  1558. 	<p class=desc>Begin the release phase.

  1559. 	</p>

  1560. 	<p class=func><span class=keyword>delay</span>(milliseconds);</p>

  1561. 	<p class=desc>Set the delay from noteOn to the attach phase.  The

  1562. 		default is zero, for no delay.

  1563. 	</p>

  1564. 	<p class=func><span class=keyword>attack</span>(milliseconds);</p>

  1565. 	<p class=desc>Set the attack time.  The default is 1.5 milliseconds.

  1566. 	</p>

  1567. 	<p class=func><span class=keyword>hold</span>(milliseconds);</p>

  1568. 	<p class=desc>Set the hold time.  The default is 0.5 milliseconds.

  1569. 	</p>

  1570. 	<p class=func><span class=keyword>decay</span>(milliseconds);</p>

  1571. 	<p class=desc>Set the decay time.  The default is 15 milliseconds.

  1572. 	</p>

  1573. 	<p class=func><span class=keyword>sustain</span>(level);</p>

  1574. 	<p class=desc>Set the sustain level.  The range is 0 to 1.0.  The

  1575. 		gain will be maintained at this level after the decay phase,

  1576. 		until noteOff() is called.

  1577. 	</p>

  1578. 	<p class=func><span class=keyword>release</span>(milliseconds);</p>

  1579. 	<p class=desc>Set the release time.  The default is 30 millisecond.

  1580. 	</p>

  1581. 	<h3>Examples</h3>

  1582. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Synthesis &gt; PlaySynthMusic

  1583. 	</p>

  1584. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Synthesis &gt; pulseWidth

  1585. 	</p>

  1586. 	<p class=exam>File &gt; Examples &gt; Audio &gt; MemoryAndCpuUsage

  1587. 	</p>

  1588. 	<h3>Notes</h3>

  1589. 	<p>To achieve the more common ADSR shape, simply

  1590.         set delay and hold to zero.</p>

  1591. 	<p>The recommended range for each of the 5 timing inputs is 0 to 50

  1592. 		milliseconds.  Up to 200 ms can be used, with somewhat reduced

  1593. 		accuracy</p>

  1594. </script>

  1595. <script type="text/x-red" data-template-name="AudioEffectEnvelope">

  1596. 	<div class="form-row">

  1597. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1598. 		<input type="text" id="node-input-name" placeholder="Name">

  1599. 	</div>

  1600. </script>

  1601. 

  1602. <script type="text/x-red" data-help-name="AudioEffectMultiply">

  1603. 	<h3>Summary</h3>

  1604. 	<div>

  1605. 	<p>Multiply two signals together, useful for amplitude modulation

  1606. 		or "voltage controlled amplification".

  1607. 	</p>

  1608. 	<p align=center><img src="img/multiply.png"><br><small>56 Hz and 1 kHz sine waves multiplied.</small></p>

  1609. 	</div>

  1610. 	<h3>Audio Connections</h3>

  1611. 	<table class=doc align=center cellpadding=3>

  1612. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1613. 		<tr class=odd><td align=center>In 0</td><td>Signal Input</td></tr>

  1614. 		<tr class=odd><td align=center>In 1</td><td>Signal Input</td></tr>

  1615. 		<tr class=odd><td align=center>Out 0</td><td>Signal with Envelope Applied</td></tr>

  1616. 	</table>

  1617. 	<h3>Functions</h3>

  1618. 	<p>There are no functions to call from the Arduino sketch.

  1619. 		This object simply multiplies the 2 signals to create

  1620. 		a continuous output

  1621. 	</p>

  1622. 	<!--

  1623. <h3>Examples</h3>

  1624. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  1625. 	</p>

  1626. -->

  1627. 	<h3>Notes</h3>

  1628. 	<p>

  1629.     </p>

  1630. </script>

  1631. <script type="text/x-red" data-template-name="AudioEffectMultiply">

  1632. 	<div class="form-row">

  1633. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1634. 		<input type="text" id="node-input-name" placeholder="Name">

  1635. 	</div>

  1636. </script>

  1637. 

  1638. <script type="text/x-red" data-help-name="AudioEffectDelay">

  1639. 	<h3>Summary</h3>

  1640. 	<div>

  1641. 	<p>Delay a signal.  Up to 8 separate delay taps can be used.</p>

  1642. 	<p align=center><img src="img/delay.png"><br><small>1 kHz burst, delayed 5.2 ms.</small></p>

  1643. 	</div>

  1644. 	<h3>Audio Connections</h3>

  1645. 	<table class=doc align=center cellpadding=3>

  1646. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1647. 		<tr class=odd><td align=center>In 0</td><td>Signal Input</td></tr>

  1648. 		<tr class=odd><td align=center>Out 0</td><td>Delay Tap #1</td></tr>

  1649. 		<tr class=odd><td align=center>Out 1</td><td>Delay Tap #2</td></tr>

  1650. 		<tr class=odd><td align=center>Out 2</td><td>Delay Tap #3</td></tr>

  1651. 		<tr class=odd><td align=center>Out 3</td><td>Delay Tap #4</td></tr>

  1652. 		<tr class=odd><td align=center>Out 4</td><td>Delay Tap #5</td></tr>

  1653. 		<tr class=odd><td align=center>Out 5</td><td>Delay Tap #6</td></tr>

  1654. 		<tr class=odd><td align=center>Out 6</td><td>Delay Tap #7</td></tr>

  1655. 		<tr class=odd><td align=center>Out 7</td><td>Delay Tap #8</td></tr>

  1656. 	</table>

  1657. 	<h3>Functions</h3>

  1658. 	<p class=func><span class=keyword>delay</span>(channel, milliseconds);</p>

  1659. 	<p class=desc>Set output channel (0 to 7) to delay the signals by

  1660. 		milliseconds.  The maximum delay is approx 333 ms.  The actual delay

  1661. 		is rounded to the nearest sample.  Each channel can be configured for

  1662. 		any delay.  There is no requirement to configure the "taps" in increasing

  1663. 		delay order.

  1664. 	</p>

  1665. 	<p class=func><span class=keyword>disable</span>(channel);</p>

  1666. 	<p class=desc>Disable a channel.  The output of this channel becomes

  1667. 		silent.  If this channel is the longest delay, memory usage is

  1668. 		automatically reduced to accomodate only the remaining channels used.

  1669. 	</p>

  1670. 	<h3>Examples</h3>

  1671. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Delay

  1672. 	</p>

  1673. 	<h3>Notes</h3>

  1674. 	<p>Memory for the delayed signal is take from the memory pool allocated by

  1675. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioConnection.html" target="_blank">AudioMemory()</a>.

  1676. 		Each block allows about 3 milliseconds of delay, so AudioMemory

  1677. 		should be increased to allow for the longest delay tap.

  1678. 	</p>

  1679. </script>

  1680. <script type="text/x-red" data-template-name="AudioEffectDelay">

  1681. 	<div class="form-row">

  1682. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1683. 		<input type="text" id="node-input-name" placeholder="Name">

  1684. 	</div>

  1685. </script>

  1686. 

  1687. <script type="text/x-red" data-help-name="AudioEffectDelayExternal">

  1688. 	<h3>Summary</h3>

  1689. 	<div>

  1690. 	<p>Delay a signal, using external memory for longer delay times!  Up to 8 separate delay taps can be used.</p>

  1691. 	<p align=center><img src="img/delay.png"><br><small>1 kHz burst, delayed 5.2 ms.</small></p>

  1692. 	</div>

  1693. 	<h3>Audio Connections</h3>

  1694. 	<table class=doc align=center cellpadding=3>

  1695. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1696. 		<tr class=odd><td align=center>In 0</td><td>Signal Input</td></tr>

  1697. 		<tr class=odd><td align=center>Out 0</td><td>Delay Tap #1</td></tr>

  1698. 		<tr class=odd><td align=center>Out 1</td><td>Delay Tap #2</td></tr>

  1699. 		<tr class=odd><td align=center>Out 2</td><td>Delay Tap #3</td></tr>

  1700. 		<tr class=odd><td align=center>Out 3</td><td>Delay Tap #4</td></tr>

  1701. 		<tr class=odd><td align=center>Out 4</td><td>Delay Tap #5</td></tr>

  1702. 		<tr class=odd><td align=center>Out 5</td><td>Delay Tap #6</td></tr>

  1703. 		<tr class=odd><td align=center>Out 6</td><td>Delay Tap #7</td></tr>

  1704. 		<tr class=odd><td align=center>Out 7</td><td>Delay Tap #8</td></tr>

  1705. 	</table>

  1706. 	<h3>Functions</h3>

  1707. 	<p class=func><span class=keyword>delay</span>(channel, milliseconds);</p>

  1708. 	<p class=desc>Set output channel (0 to 7) to delay the signals by

  1709. 		milliseconds.  The maximum delay is approx 333 ms.  The actual delay

  1710. 		is rounded to the nearest sample.  Each channel can be configured for

  1711. 		any delay.  There is no requirement to configure the "taps" in increasing

  1712. 		delay order.

  1713. 	</p>

  1714. 	<p class=func><span class=keyword>disable</span>(channel);</p>

  1715. 	<p class=desc>Disable a channel.  The output of this channel becomes

  1716. 		silent.  If this channel is the longest delay, memory usage is

  1717. 		automatically reduced to accomodate only the remaining channels used.

  1718. 	</p>

  1719. 	<h3>Hardware</h3>

  1720. 	<p>By default, or when <span class=literal>AUDIO_MEMORY_23LC1024</span> is used (see below),

  1721. 		 a single 23LC1024 RAM chip is used, with these pins:

  1722.     <table class=doc align=center cellpadding=3>

  1723.         <tr class=top><th>Pin</th><th>Signal</th></tr>

  1724.         <tr class=odd><td align=center>6</td><td>CS</td></tr>

  1725.         <tr class=odd><td align=center>7</td><td>MOSI</td></tr>

  1726.         <tr class=odd><td align=center>12</td><td>MISO</td></tr>

  1727.         <tr class=odd><td align=center>14</td><td>SCK</td></tr>

  1728.     </table>

  1729. 	</p>

  1730. 	<p>When <span class=literal>AUDIO_MEMORY_MEMORYBOARD</span> is used, up to six

  1731. 		23LC1024 chips are used.

  1732. 	</p>

  1733. 	<p align=center><img src="img/memoryboard.jpg"><br><small><a href="https://oshpark.com/shared_projects/KZt5PaU7" target="_blank">Memoryboard 4</a></small></p>

  1734. 	<p>

  1735.     <table class=doc align=center cellpadding=3>

  1736.         <tr class=top><th>Pin</th><th>Signal</th></tr>

  1737.         <tr class=odd><td align=center>2</td><td>CS0 (encoded)</td></tr>

  1738.         <tr class=odd><td align=center>3</td><td>CS1 (encoded)</td></tr>

  1739.         <tr class=odd><td align=center>4</td><td>CS2 (encoded)</td></tr>

  1740.         <tr class=odd><td align=center>7</td><td>MOSI</td></tr>

  1741.         <tr class=odd><td align=center>12</td><td>MISO</td></tr>

  1742.         <tr class=odd><td align=center>14</td><td>SCK</td></tr>

  1743.     </table>

  1744. 	</p>

  1745. 	<p>

  1746. 	If fewer than 6 chips are soldered, the optional parameter for maximum delay

  1747. 	must be used.  See below for details.  Each chip provides 1485 ms of delay

  1748. 	memory, so the total of all objects using AUDIO_MEMORY_MEMORYBOARD must not

  1749. 	exceed the amount of memory physically present.

  1750. 	</p>

  1751. 	<h3>Examples</h3>

  1752. 	<p>

  1753. 	<a href="https://www.youtube.com/watch?v=d80d1HWy5_s" target="_blank">Demo Video</a> (YouTube)

  1754. 	</p>

  1755. 	<!--

  1756.  <p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Delay

  1757. 	</p>

  1758. -->

  1759. 	<p>

  1760. 	<a href="https://forum.pjrc.com/threads/29276-Limits-of-delay-effect-in-audio-library?p=79436&viewfull=1#post79436" target="_blank">Forum Conversaton</a> (with sample code)

  1761. 	</p>

  1762. 	<h3>Notes</h3>

  1763. 	<p>External RAM allows for longer delays without consuming

  1764. 		limited internal RAM.  However, SPI communication is required,

  1765. 		which consumes much more CPU time.  The

  1766. 		<a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html">AudioProcessorUsageMax</a>

  1767. 		function may be used to monitor how much CPU time is consumed.

  1768. 	</p>

  1769. 	<p>You may specify the type of hardware to be used by editing the code.  AUDIO_MEMORY_23LC1024

  1770. 		specifies a single 23LC1024 chip.  AUDIO_MEMORY_MEMORYBOARD allows using up to 6 of these

  1771. 		chips.

  1772. 	</p>

  1773. 	<p class=desc><span class=keyword>AudioEffectDelayExternal</span>  delayExt1(<span class=literal>AUDIO_MEMORY_23LC1024</span>);

  1774. 	</p>

  1775. 	<p>You may also create more than one delay using the same hardware, where the memory is partitioned

  1776. 		by specifying a maximum delay in milliseconds.  This can be useful if you wish to delay both

  1777. 		channels of a stereo signal.

  1778. 

  1779. 	<p class=desc><span class=keyword>AudioEffectDelayExternal</span>  delayExt1(<span class=literal>AUDIO_MEMORY_23LC1024</span>, 700);<br><span class=keyword>AudioEffectDelayExternal</span>  delayExt2(<span class=literal>AUDIO_MEMORY_23LC1024</span>, 700);

  1780. 	</p>

  1781. </script>

  1782. <script type="text/x-red" data-template-name="AudioEffectDelayExternal">

  1783. 	<div class="form-row">

  1784. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1785. 		<input type="text" id="node-input-name" placeholder="Name">

  1786. 	</div>

  1787. </script>

  1788. 

  1789. <script type="text/x-red" data-help-name="AudioEffectBitcrusher">

  1790.     <h3>Summary</h3>

  1791.     <p>Reduce the samplerate and/or bitdepth of a source signal, resulting in

  1792. 		a distorted sound.</p>

  1793.     <h3>Audio Connections</h3>

  1794.     <table class=doc align=center cellpadding=3>

  1795.         <tr class=top><th>Port</th><th>Purpose</th></tr>

  1796.         <tr class=odd><td align=center>In 0</td><td>Signal Input</td></tr>

  1797.         <tr class=odd><td align=center>Out 0</td><td>Signal Output</td></tr>

  1798.     </table>

  1799.     <h3>Parameters</h3>

  1800.     <p class=func><span class=keyword>bits</span>(xcrushBits);</p>

  1801.     <p class=desc>xcrushBits sets the bitdepth, from 1 to 16. A Value of 16

  1802.     does not crush the bitdepth, and is effectively a passthru for this part

  1803.     of the function.</p>

  1804. 

  1805.     <p class=func><span class=keyword>sampleRate</span>(xsampleRate);</p>

  1806. 

  1807.     <p class=desc>xsampleRate sets the frequency, from 1 to 44100Hz, however it

  1808.     works in integer steps so you will only really get a handful of results from

  1809.     the many samplerates you can pass. 44100 is passthru.</p>

  1810. 

  1811.     <p class=desc>set xbitDepth to 16 and xsampleRate to 44100 to pass audio

  1812.     	through without any Bitcrush effect.</p>

  1813.     <h3>Examples</h3>

  1814.     <p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Bitcrusher

  1815.     </p>

  1816.     <h3>Notes</h3>

  1817.     <p>Needs a lot of improvement. Options for anti-aliasing would be nice in

  1818.     the future, but for now, it's rough, it's dirty and it sounds a bit like

  1819.     Nine Inch Nails.

  1820.     </p>

  1821.     <p><a href="http://www.pjrc.com/teensy/td_libs_AudioProcessorUsage.html" target="_blank">AudioNoInterrupts()</a>

  1822.         should be used when changing

  1823.         settings on multiple objects, so all changes always take effect

  1824.         at the same moment.

  1825.     </p>

  1826. </script>

  1827. <script type="text/x-red" data-template-name="AudioEffectBitcrusher">

  1828.     <div class="form-row">

  1829.         <label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1830.         <input type="text" id="node-input-name" placeholder="Name">

  1831.     </div>

  1832. </script>

  1833. 

  1834. <script type="text/x-red" data-help-name="AudioFilterBiquad">

  1835. 	<h3>Summary</h3>

  1836. 	<div>

  1837. 	<p>Biquadratic cascaded filter, useful for all sorts of filtering.

  1838. 		Up to 4 stages may be cascaded.

  1839. 	</p>

  1840. 	<p align=center><img src="img/biquad.png"></p>

  1841. 	</div>

  1842. 	<h3>Audio Connections</h3>

  1843. 	<table class=doc align=center cellpadding=3>

  1844. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1845. 		<tr class=odd><td align=center>In 0</td><td>Signal to be filtered</td></tr>

  1846. 		<tr class=odd><td align=center>Out 0</td><td>Filtered Signal Output</td></tr>

  1847. 	</table>

  1848. 	<h3>Functions</h3>

  1849. 	<p class=func><span class=keyword>setLowpass</span>(stage, frequency, Q);</p>

  1850. 	<p class=desc>Configure one stage of the filter (0 to 3) with low pass

  1851. 		response, with the specified corner frequency and Q shape.  If Q is

  1852. 		higher that 0.7071, be careful of filter gain (see below).

  1853. 	</p>

  1854. 	<p class=func><span class=keyword>setHighpass</span>(stage, frequency, Q);</p>

  1855. 	<p class=desc>Configure one stage of the filter (0 to 3) with high pass

  1856. 		response, with the specified corner frequency and Q shape.  If Q is

  1857. 		higher that 0.7071, be careful of filter gain (see below).

  1858. 	</p>

  1859. 	<p class=func><span class=keyword>setBandpass</span>(stage, frequency, Q);</p>

  1860. 	<p class=desc>Configure one stage of the filter (0 to 3) with band pass

  1861. 		response.  The filter has unity gain at the specified frequency.  Q

  1862. 		controls the width of frequencies allowed to pass.

  1863. 	</p>

  1864. 	<p class=func><span class=keyword>setNotch</span>(stage, frequency, Q);</p>

  1865. 	<p class=desc>Configure one stage of the filter (0 to 3) with band reject (notch)

  1866. 		response.  Q controls the width of rejected frequencies.

  1867. 	</p>

  1868. 	<p class=func><span class=keyword>setCoefficients</span>(stage, array[5]);</p>

  1869. 	<p class=desc>Configure one stage of the filter (0 to 3) with an arbitrary

  1870. 		filter response.  The array of coefficients is in order: B0, B1, B2, A1, A2.

  1871. 		Each coefficient must be less than 2.0 and greater than -2.0.  The array

  1872. 		should be type double.  Alternately, it may be type int, where 1.0 is

  1873. 		represented with 1073741824 (2<sup>30</sup>).

  1874. 	</p>

  1875. 	<h3>Examples</h3>

  1876. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Filter

  1877. 	</p>

  1878. 	<h3>Notes</h3>

  1879. 	<p>Filters can with gain must have their input signals attenuated, so the

  1880. 		signal does not exceed 1.0.

  1881. 	</p>

  1882. 	<p>This object implements up to 4 cascaded stages.  Unconfigured stages will

  1883. 		not pass any signal.

  1884. 	</p>

  1885. 	<p>Biquad filters with low corner frequency (under about 400 Hz) can run into

  1886. 		trouble with limited numerical precision, causing the filter to perform

  1887. 		poorly.  For very low corner frequency, the State Variable (Chamberlin)

  1888. 		filter should be used.

  1889. 	</p>

  1890. </script>

  1891. <script type="text/x-red" data-template-name="AudioFilterBiquad">

  1892. 	<div class="form-row">

  1893. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1894. 		<input type="text" id="node-input-name" placeholder="Name">

  1895. 	</div>

  1896. </script>

  1897. 

  1898. <script type="text/x-red" data-help-name="AudioFilterFIR">

  1899. 	<h3>Summary</h3>

  1900. 	<div>

  1901. 	<p>Finite impulse response filter, useful for all sorts of filtering.

  1902. 	</p>

  1903. 	<p align=center><img src="img/fir_filter.png"></p>

  1904. 	</div>

  1905. 	<h3>Audio Connections</h3>

  1906. 	<table class=doc align=center cellpadding=3>

  1907. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1908. 		<tr class=odd><td align=center>In 0</td><td>Signal to be filtered</td></tr>

  1909. 		<tr class=odd><td align=center>Out 0</td><td>Filtered Signal Output</td></tr>

  1910. 	</table>

  1911. 	<h3>Functions</h3>

  1912. 	<p class=func><span class=keyword>begin</span>(array, length);</p>

  1913. 	<p class=desc>Initialize the filter.  The array must be 16 bit integers (the

  1914. 		filter's impulse response), and

  1915. 		length indicates the number of points in the array.  Array may also be

  1916. 		FIR_PASSTHRU (length = 0), to directly pass the input to output without

  1917. 		filtering.

  1918. 	</p>

  1919. 	<p class=func><span class=keyword>end</span>();</p>

  1920. 	<p class=desc>Turn the filter off.

  1921. 	</p>

  1922. 	<h3>Examples</h3>

  1923. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Filter_FIR

  1924. 	</p>

  1925. 	<h3>Notes</h3>

  1926. 	<p>FIR filters requires more CPU time than Biquad (IIR), but they can

  1927. 		implement filters with better phase response.

  1928. 	</p>

  1929. 	<p>A 100 point filter requires 9% CPU time on Teensy 3.1.  The maximum

  1930. 		supported filter length is 200 points.

  1931. 	</p>

  1932. 	<p>The free

  1933. 		<a href="http://t-filter.appspot.com/fir/index.html" target="_blank"> TFilter Design Tool</a>

  1934. 		can be used to create the impulse response array.  Be sure to set the sampling

  1935. 		frequency to 44117 HZ (it defaults to only 2000 Hz) and the output type to "int" (16 bit).

  1936. 	</p>

  1937. 	<p>

  1938. 		If you use TFilter Design's "C/C++ array" option, it's output has "int" definition, which

  1939. 		is 32 bits on Teensy 3.1.  Edit "int" to "short" for an array of 16 bit numbers,

  1940. 		and add "const" to avoid consuming extra RAM.

  1941. 	</p>

  1942. </script>

  1943. <script type="text/x-red" data-template-name="AudioFilterFIR">

  1944. 	<div class="form-row">

  1945. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  1946. 		<input type="text" id="node-input-name" placeholder="Name">

  1947. 	</div>

  1948. </script>

  1949. 

  1950. <script type="text/x-red" data-help-name="AudioFilterStateVariable">

  1951. 	<h3>Summary</h3>

  1952. 	<p>A State Variable (Chamberlin) Filter with 12 dB/octave roll-off,

  1953. 		adjustable resonance, and optional signal control of corner

  1954. 		frequency.</p>

  1955. 	<h3>Audio Connections</h3>

  1956. 	<table class=doc align=center cellpadding=3>

  1957. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  1958. 		<tr class=odd><td align=center>In 0</td><td>Signal to Filter</td></tr>

  1959. 		<tr class=odd><td align=center>In 1</td><td>Frequency Control</td></tr>

  1960. 		<tr class=odd><td align=center>Out 0</td><td>Low Pass Output</td></tr>

  1961. 		<tr class=odd><td align=center>Out 1</td><td>Band Pass Output</td></tr>

  1962. 		<tr class=odd><td align=center>Out 2</td><td>High Pass Output</td></tr>

  1963. 	</table>

  1964. 	<h3>Functions</h3>

  1965. 	<p class=func><span class=keyword>frequency</span>(freq);</p>

  1966. 	<p class=desc>Set the filter's corner frequency.  When a signal is

  1967. 		connected to the control input, the filter will implement this

  1968. 		frequency when the signal is zero.

  1969. 	</p>

  1970. 	<p class=func><span class=keyword>resonance</span>(Q);</p>

  1971. 	<p class=desc>Set the filter's resonance.  Q ranges from 0.7 to 5.0.

  1972. 		Resonance greater than 0.707 will amplify the signal near the

  1973. 		corner frequency.  You must attenuate the signal before input

  1974. 		to this filter, to prevent clipping.

  1975. 	</p>

  1976. 	<p class=func><span class=keyword>octaveControl</span>(octaves);</p>

  1977. 	<p class=desc>Set how much (in octaves) the control signal can alter

  1978. 		the filter's corner freqency.  Range is 0 to 7 octaves.  For

  1979. 		example, when set to 2.5, a full scale positive signal (1.0) will

  1980. 		shift the filter frequency up 2.5 octaves, and a full scale negative

  1981. 		signal will shift it down 2.5 octaves.

  1982. 	</p>

  1983. 	<!--

  1984. <h3>Examples</h3>

  1985. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  1986. 	</p>

  1987. -->

  1988. 	<h3>Notes</h3>

  1989. 	<p>

  1990. 		When controlled by a signal, the equation for the filter

  1991. 		frequency is:

  1992. 	</p>

  1993. 	<p>

  1994. 		F = Fcenter * 2^<sup>(signal * octaves)</sup>

  1995. 		<br><small>If anyone knows how to do HTML equations, please

  1996. 		help me improve this.....</small>

  1997. 	</p>

  1998. 	<p>When operating with signal control of corner frequency, this

  1999. 		object uses approximately 4% of the CPU time on Teensy 3.1.

  2000. 	</p>

  2001. </script>

  2002. <script type="text/x-red" data-template-name="AudioFilterFIR">

  2003. 	<div class="form-row">

  2004. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2005. 		<input type="text" id="node-input-name" placeholder="Name">

  2006. 	</div>

  2007. </script>

  2008. 

  2009. <script type="text/x-red" data-help-name="AudioAnalyzePeak">

  2010. 	<h3>Summary</h3>

  2011. 	<p>Track the signal peak amplitude.  Very useful for simple

  2012. 		audio level response projects, and general troubleshooting.</p>

  2013. 	<h3>Audio Connections</h3>

  2014. 	<table class=doc align=center cellpadding=3>

  2015. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  2016. 		<tr class=odd><td align=center>In 0</td><td>Signal to analyze</td></tr>

  2017. 	</table>

  2018. 	<h3>Functions</h3>

  2019. 	<p class=func><span class=keyword>available</span>();</p>

  2020. 	<p class=desc>Returns true each time new peak data is available.

  2021. 	</p>

  2022. 	<p class=func><span class=keyword>read</span>();</p>

  2023. 	<p class=desc>Read the highest peak value since the last read.

  2024. 		Return is from 0.0 to 1.0.

  2025. 	</p>

  2026. 	<h3>Examples</h3>

  2027. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; PeakMeterMono

  2028. 	</p>

  2029. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; PeakMeterStereo

  2030. 	</p>

  2031. 	<h3>Notes</h3>

  2032. 	<p></p>

  2033. </script>

  2034. <script type="text/x-red" data-template-name="AudioAnalyzePeak">

  2035. 	<div class="form-row">

  2036. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2037. 		<input type="text" id="node-input-name" placeholder="Name">

  2038. 	</div>

  2039. </script>

  2040. 

  2041. <script type="text/x-red" data-help-name="AudioAnalyzeFFT256">

  2042. 	<h3>Summary</h3>

  2043. 	<p>Compute a 256 point Fast Fourier Transform (FFT) frequency analysis,

  2044. 		with real value (magnitude) output.  The frequency resolution is

  2045. 		172 Hz, useful for simple audio visualization.</p>

  2046. 	<h3>Audio Connections</h3>

  2047. 	<table class=doc align=center cellpadding=3>

  2048. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  2049. 		<tr class=odd><td align=center>In 0</td><td>Signal to convert to frequency bins</td></tr>

  2050. 	</table>

  2051. 	<h3>Functions</h3>

  2052. 	<p class=func><span class=keyword>available</span>();</p>

  2053. 	<p class=desc>Returns true each time the FFT analysis produces new output data.

  2054. 	</p>

  2055. 	<p class=func><span class=keyword>read</span>(binNumber);</p>

  2056. 	<p class=desc>Read a single frequency bin, from 0 to 127.  The result is scaled

  2057. 		so 1.0 represents a full scale sine wave.

  2058. 	</p>

  2059. 	<p class=func><span class=keyword>read</span>(firstBin, lastBin);</p>

  2060. 	<p class=desc>Read several frequency bins, returning their sum.  The higher

  2061. 		audio octaves are represented by many bins, which are typically read

  2062. 		as a group for audio visualization.

  2063. 	</p>

  2064. 	<p class=func><span class=keyword>averageTogether</span>(number);</p>

  2065. 	<p class=desc>New data is produced very radidly, approximately 344 times

  2066. 		per second.  Multiple outputs can be averaged together, so available()

  2067. 		returns true at a slower rate.

  2068. 	</p>

  2069. 	<p class=func><span class=keyword>windowFunction</span>(window);</p>

  2070. 	<p class=desc>Set the window function to be used.  AudioWindowHanning256

  2071. 		is the default.  Windowing may be disabled by NULL, but windowing

  2072. 		should be used for all non-periodic (music) signals, and all periodic

  2073. 		signals that are not exact integer division of the sample rate.

  2074. 	</p>

  2075. 

  2076. 	<h3>Examples</h3>

  2077. 	<p class=exam>File &gt; Examples &gt; Audio &gt; MemoryAndCpuUsage

  2078. 	</p>

  2079. 	<h3>Notes</h3>

  2080. 	<p>The raw 16 bit output data bins may be access with myFFT.output[num], where

  2081. 		num is 0 to 127.</p>

  2082. 	<p>TODO: caveats about spectral leakage vs frequency precision for arbitrary signals</p>

  2083. 	<p>Window Types:

  2084. 		<ul>

  2085. 		<li><span class=literal>AudioWindowHanning256</span> (default)</li>

  2086. 		<li><span class=literal>AudioWindowBartlett256</span></li>

  2087. 		<li><span class=literal>AudioWindowBlackman256</span></li>

  2088. 		<li><span class=literal>AudioWindowFlattop256</span></li>

  2089. 		<li><span class=literal>AudioWindowBlackmanHarris256</span></li>

  2090. 		<li><span class=literal>AudioWindowNuttall256</span></li>

  2091. 		<li><span class=literal>AudioWindowBlackmanNuttall256</span></li>

  2092. 		<li><span class=literal>AudioWindowWelch256</span></li>

  2093. 		<li><span class=literal>AudioWindowHamming256</span></li>

  2094. 		<li><span class=literal>AudioWindowCosine256</span></li>

  2095. 		<li><span class=literal>AudioWindowTukey256</span></li>

  2096. 		</ul>

  2097. 	</p>

  2098. </script>

  2099. <script type="text/x-red" data-template-name="AudioAnalyzeFFT256">

  2100. 	<div class="form-row">

  2101. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2102. 		<input type="text" id="node-input-name" placeholder="Name">

  2103. 	</div>

  2104. </script>

  2105. 

  2106. <script type="text/x-red" data-help-name="AudioAnalyzeFFT1024">

  2107. 	<h3>Summary</h3>

  2108. 	<p>Compute a 1024 point Fast Fourier Transform (FFT) frequency analysis,

  2109. 		with real value (magnitude) output.  The frequency resolution is

  2110. 		43 Hz, useful detailed for audio visualization.</p>

  2111. 	<h3>Audio Connections</h3>

  2112. 	<table class=doc align=center cellpadding=3>

  2113. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  2114. 		<tr class=odd><td align=center>In 0</td><td>Signal to convert to frequency bins</td></tr>

  2115. 	</table>

  2116. 	<h3>Functions</h3>

  2117. 	<p class=func><span class=keyword>available</span>();</p>

  2118. 	<p class=desc>Returns true each time the FFT analysis produces new output data.

  2119. 	</p>

  2120. 	<p class=func><span class=keyword>read</span>(binNumber);</p>

  2121. 	<p class=desc>Read a single frequency bin, from 0 to 511.  The result is scaled

  2122. 		so 1.0 represents a full scale sine wave.

  2123. 	</p>

  2124. 	<p class=func><span class=keyword>read</span>(firstBin, lastBin);</p>

  2125. 	<p class=desc>Read several frequency bins, returning their sum.  The higher

  2126. 		audio octaves are represented by many bins, which are typically read

  2127. 		as a group for audio visualization.

  2128. 	</p>

  2129. 	<p class=func><span class=keyword>averageTogether</span>(number);</p>

  2130. 	<p class=desc>This function does nothing.  The 1024 point FFT always

  2131. 		updates at approximately 86 times per second.

  2132. 	</p>

  2133. 	<p class=func><span class=keyword>windowFunction</span>(window);</p>

  2134. 	<p class=desc>Set the window function to be used.  AudioWindowHanning1024

  2135. 		is the default.  Windowing may be disabled by NULL, but windowing

  2136. 		should be used for all non-periodic (music) signals, and all periodic

  2137. 		signals that are not exact integer division of the sample rate.

  2138. 	</p>

  2139. 	<h3>Examples</h3>

  2140. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; FFT

  2141. 	</p>

  2142. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; SpectrumAnalyzerBasic

  2143. 	</p>

  2144. 	<h3>Notes</h3>

  2145. 	<p>The raw 16 bit output data bins may be access with myFFT.output[num], where

  2146. 		num is 0 to 511.</p>

  2147. 	<p>TODO: caveats about spectral leakage vs frequency precision for arbitrary signals</p>

  2148. 	<p>Window Types:

  2149. 		<ul>

  2150. 		<li><span class=literal>AudioWindowHanning1024</span> (default)</li>

  2151. 		<li><span class=literal>AudioWindowBartlett1024</span></li>

  2152. 		<li><span class=literal>AudioWindowBlackman1024</span></li>

  2153. 		<li><span class=literal>AudioWindowFlattop1024</span></li>

  2154. 		<li><span class=literal>AudioWindowBlackmanHarris1024</span></li>

  2155. 		<li><span class=literal>AudioWindowNuttall1024</span></li>

  2156. 		<li><span class=literal>AudioWindowBlackmanNuttall1024</span></li>

  2157. 		<li><span class=literal>AudioWindowWelch1024</span></li>

  2158. 		<li><span class=literal>AudioWindowHamming1024</span></li>

  2159. 		<li><span class=literal>AudioWindowCosine1024</span></li>

  2160. 		<li><span class=literal>AudioWindowTukey1024</span></li>

  2161. 		</ul>

  2162. 	</p>

  2163. 	<p>1024 point FFT has a peak CPU usage of approx 52% on Teensy 3.1.

  2164. 		Average usage is much lower.  Future versions might distribute the

  2165. 		load more evenly over time....

  2166. 	</p>

  2167. </script>

  2168. <script type="text/x-red" data-template-name="AudioAnalyzeFFT1024">

  2169. 	<div class="form-row">

  2170. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2171. 		<input type="text" id="node-input-name" placeholder="Name">

  2172. 	</div>

  2173. </script>

  2174. 

  2175. <script type="text/x-red" data-help-name="AudioAnalyzeToneDetect">

  2176. 	<h3>Summary</h3>

  2177. 	<p>Detect the level of a single tone</p>

  2178. 	<h3>Audio Connections</h3>

  2179. 	<table class=doc align=center cellpadding=3>

  2180. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  2181. 		<tr class=odd><td align=center>In 0</td><td>Signal to analyze</td></tr>

  2182. 	</table>

  2183. 	<h3>Functions</h3>

  2184. 	<p class=func><span class=keyword>frequency</span>(freq);</p>

  2185. 	<p class=desc>Set the frequency to detect.  The default detection time

  2186. 		will be 10 cycles of this frequency.

  2187. 	</p>

  2188. 	<p class=func><span class=keyword>frequency</span>(freq, cycles);</p>

  2189. 	<p class=desc>Set the frequency to detect, and the number of cycles.

  2190. 		Longer detection time (more cycles) will give higher precision,

  2191. 		but of course slower response.

  2192. 	</p>

  2193. 	<p class=func><span class=keyword>available</span>();</p>

  2194. 	<p class=desc>Returns true (non-zero) each time a detection interval

  2195. 		(number of cycles) completed and a new level is detected.

  2196. 	</p>

  2197. 	<p class=func><span class=keyword>read</span>();</p>

  2198. 	<p class=desc>Read the detected signal level.  Range is 0 to 1.0.

  2199. 	</p>

  2200. 	<p class=func><span class=keyword>threshold</span>(level);</p>

  2201. 	<p class=desc>Set a detection threshold, where the bool test operation

  2202. 		will return true if at or above this level, or false when below.

  2203. 	</p>

  2204. 	<p class=func>(bool)</p>

  2205. 	<p class=desc>By testing the object as a boolean value, you can respond

  2206. 		to detection of a tone.

  2207. 	</p>

  2208. 	<h3>Examples</h3>

  2209. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; DialTone_Serial

  2210. 	</p>

  2211. 	<p class=exam>File &gt; Examples &gt; Audio &gt; Analysis &gt; DialTone_7segment

  2212. 	</p>

  2213. 	<h3>Notes</h3>

  2214. 	<p>Low frequency detection has trouble with numerical precision.

  2215. 		Works really well for all 8 DTMF frequencies, but fails for

  2216. 		detecting "sub audible tones" used in some control applications.</p>

  2217. 	<p>The (bool) test continues to return true until the next detection

  2218. 		interval (the configured number of cycles).  This behavior may

  2219. 		change in future versions, for a single true each time the signal

  2220. 		is detected, and then false for the remainder of that interval.</p>

  2221. </script>

  2222. <script type="text/x-red" data-template-name="AudioAnalyzeToneDetect">

  2223. 	<div class="form-row">

  2224. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2225. 		<input type="text" id="node-input-name" placeholder="Name">

  2226. 	</div>

  2227. </script>

  2228. 

  2229. <script type="text/x-red" data-help-name="AudioAnalyzePrint">

  2230. 	<h3>Summary</h3>

  2231. 	<p>Print raw audio data to the Arduino Serial Monitor.  This

  2232. 		object creates massive output quickly, and should not normally be used.</p>

  2233. 	<h3>Audio Connections</h3>

  2234. 	<table class=doc align=center cellpadding=3>

  2235. 		<tr class=top><th>Port</th><th>Purpose</th></tr>

  2236. 		<tr class=odd><td align=center>In 0</td><td>Signal to print</td></tr>

  2237. 	</table>

  2238. 	<h3>Functions</h3>

  2239. 	<p class=func><span class=keyword>name</span>(string);</p>

  2240. 	<p class=desc>blah blah blah blah

  2241. 	</p>

  2242. 	<p class=func><span class=keyword>trigger</span>();</p>

  2243. 	<p class=desc>blah blah blah blah

  2244. 	</p>

  2245. 	<p class=func><span class=keyword>trigger</span>(level, edge);</p>

  2246. 	<p class=desc>blah blah blah blah

  2247. 	</p>

  2248. 	<p class=func><span class=keyword>delay</span>(samples);</p>

  2249. 	<p class=desc>blah blah blah blah

  2250. 	</p>

  2251. 	<p class=func><span class=keyword>length</span>(samples);</p>

  2252. 	<p class=desc>blah blah blah blah

  2253. 	</p>

  2254. 	<!--

  2255. <h3>Examples</h3>

  2256. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  2257. 	</p>

  2258. -->

  2259. 	<h3>Notes</h3>

  2260. 	<p>This object doesn't work very well and probably should not be used.</p>

  2261. </script>

  2262. <script type="text/x-red" data-template-name="AudioAnalyzePrint">

  2263. 	<div class="form-row">

  2264. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2265. 		<input type="text" id="node-input-name" placeholder="Name">

  2266. 	</div>

  2267. </script>

  2268. 

  2269. <script type="text/x-red" data-help-name="AudioControlSGTL5000">

  2270. 	<h3>Summary</h3>

  2271. 	<p>Control the SGTL5000 chip on the

  2272. 		<a href="http://www.pjrc.com/store/teensy3_audio.html" target="_blank">audio shield</a>.

  2273. 		SGTL5000 is always used in slave mode, where Teensy controls

  2274. 		all I2S timing.

  2275. 	</p>

  2276. 	<p align=center><img src="img/sgtl5000closeup.jpg"></p>

  2277. 	<h3>Audio Connections</h3>

  2278. 	<p>This object has no audio inputs or outputs.  Separate i2s objects

  2279. 		are used to send and receive audio data.  I2S master mode objects

  2280. 		must be used, because this object configures the SGTL5000 in slave

  2281. 		mode, where it depends on Teensy to provide all I2S clocks.

  2282. 		This object controls

  2283. 		how the SGTL5000 will use those I2S audio streams.</p>

  2284. 

  2285. 	<h3>Functions</h3>

  2286. 	<p>These are the most commonly used SGTL5000 functions.</p>

  2287. 	<p class=func><span class=keyword>enable</span>();</p>

  2288. 	<p class=desc>Start the SGTL5000.  This function should be called first.

  2289. 	</p>

  2290. 	<p class=func><span class=keyword>volume</span>(level);</p>

  2291. 	<p class=desc>Set the headphone volume level.  Range is 0 to 1.0, but

  2292. 		0.8 corresponds to the maximum undistorted output for a full scale

  2293. 		signal.  Usually 0.5 is a comfortable listening level.  The line

  2294. 		level outputs are <em>not</em> changed by this function.

  2295. 	</p>

  2296. 	<p class=func><span class=keyword>inputSelect</span>(input);</p>

  2297. 	<p class=desc>Select which input to use: AUDIO_INPUT_LINEIN or AUDIO_INPUT_MIC.

  2298. 	</p>

  2299. 	<p class=func><span class=keyword>micGain</span>(dB);</p>

  2300. 	<p class=desc>When using the microphone input, set the amplifier gain.

  2301. 		The input number is in decibels, from 0 to 63.

  2302. 	</p>

  2303. 

  2304. 	<h3>Signal Levels</h3>

  2305. 

  2306. 	<p>The default signal levels should be used for most applications,

  2307. 		but these functions allow you to customize the analog signals.</p>

  2308. 

  2309. 	<p class=func><span class=keyword>muteHeadphone</span>();</p>

  2310. 	<p class=desc>Silence the headphone output.

  2311. 	</p>

  2312. 	<p class=func><span class=keyword>unmuteHeadphone</span>();</p>

  2313. 	<p class=desc>Turn the headphone output on.

  2314. 	</p>

  2315. 	<p class=func><span class=keyword>muteLineout</span>();</p>

  2316. 	<p class=desc>Silence the line level outputs.

  2317. 	</p>

  2318. 	<p class=func><span class=keyword>unmuteLineout</span>();</p>

  2319. 	<p class=desc>Turn the line level outputs on.

  2320. 	</p>

  2321. 	<p class=func><span class=keyword>lineInLevel</span>(both);</p>

  2322. 	<p class=desc style="padding-bottom:0.2em;">Adjust the sensitivity of the line-level inputs.

  2323. 		Fifteen settings are possible:

  2324. 	</p>

  2325. <pre class="desc">

  2326.  0: 3.12 Volts p-p

  2327.  1: 2.63 Volts p-p

  2328.  2: 2.22 Volts p-p

  2329.  3: 1.87 Volts p-p

  2330.  4: 1.58 Volts p-p

  2331.  5: 1.33 Volts p-p  (default)

  2332.  6: 1.11 Volts p-p

  2333.  7: 0.94 Volts p-p

  2334.  8: 0.79 Volts p-p

  2335.  9: 0.67 Volts p-p

  2336. 10: 0.56 Volts p-p

  2337. 11: 0.48 Volts p-p

  2338. 12: 0.40 Volts p-p

  2339. 13: 0.34 Volts p-p

  2340. 14: 0.29 Volts p-p

  2341. 15: 0.24 Volts p-p

  2342. </pre>

  2343. 	<p class=func><span class=keyword>lineInLevel</span>(left, right);</p>

  2344. 	<p class=desc>Adjust the sensitivity of the line-level inputs, with different

  2345. 		settings for left and right.  The same 15 settings are available.

  2346. 	</p>

  2347. 	<p class=func><span class=keyword>lineOutLevel</span>(both);</p>

  2348. 	<p class=desc style="padding-bottom:0.2em;">Adjust the line level output

  2349. 		voltage range.  The following settings are possible:

  2350. 	</p>

  2351. <pre class="desc">

  2352. 13: 3.16 Volts p-p

  2353. 14: 2.98 Volts p-p

  2354. 15: 2.83 Volts p-p

  2355. 16: 2.67 Volts p-p

  2356. 17: 2.53 Volts p-p

  2357. 18: 2.39 Volts p-p

  2358. 19: 2.26 Volts p-p

  2359. 20: 2.14 Volts p-p

  2360. 21: 2.02 Volts p-p

  2361. 22: 1.91 Volts p-p

  2362. 23: 1.80 Volts p-p

  2363. 24: 1.71 Volts p-p

  2364. 25: 1.62 Volts p-p

  2365. 26: 1.53 Volts p-p

  2366. 27: 1.44 Volts p-p

  2367. 28: 1.37 Volts p-p

  2368. 29: 1.29 Volts p-p  (default)

  2369. 30: 1.22 Volts p-p

  2370. 31: 1.16 Volts p-p

  2371. </pre>

  2372. 	<p class=func><span class=keyword>lineOutLevel</span>(left, right);</p>

  2373. 	<p class=desc>Adjust the line level outout voltage range, with separate

  2374. 		settings for left and right.  The same settings (13 to 31) are available.

  2375. 	</p>

  2376. 

  2377. 

  2378. 	<h3>Signal Conditioning</h3>

  2379. 

  2380. 	<p>Usually these digital signal conditioning features should be left at their

  2381. 		default settings.

  2382. 	</p>

  2383. 

  2384. 	<p class=func><span class=keyword>adcHighPassFilterFreeze</span>();</p>

  2385. 	<p class=desc>By default, the analog input (either line-level inputs or mic)

  2386. 		is high-pass filtered, to remove any DC component.  This function

  2387. 		freezes the filter, so the current DC component is still substracted, but

  2388. 		the filter stops tracking any DC or low frequency changes.

  2389. 	</p>

  2390. 	<p class=func><span class=keyword>adcHighPassFilterDisable</span>();</p>

  2391. 	<p class=desc>Completely disable the analog input filter.  DC and sub-audible

  2392. 		low frequencies are allowed to enter the digital signal.

  2393. 	</p>

  2394. 	<p class=func><span class=keyword>adcHighPassFilterEnable</span>();</p>

  2395. 	<p class=desc>Turn the DC-blocking filter back on, if disabled, or

  2396. 		allows it to resume tracking DC and low frequency changes, if

  2397. 		previously frozen. This is the default setting.

  2398. 	</p>

  2399. 	<p class=func><span class=keyword>dacVolume</span>(both);</p>

  2400. 	<p class=desc>Normally output volume should be used with volume(), which

  2401. 		changes the analog gain in the headphone amplifier.  This function

  2402. 		on the other hand controls digital attenuation before conversion to analog, which

  2403. 		reduces resolution, but allows another fine control of output

  2404. 		signal level.  The ranges is 0 to 1.0, with the default (no digital attenuation)

  2405. 		at 1.0.

  2406. 	</p>

  2407. 	<p  class=desc>dacVolume uses zero-crossing detect to avoid clicks, and ramping is handled by

  2408. 	the chip so that a new volume may be set directly in a single call.

  2409. 	</p>

  2410. 	<p class=func><span class=keyword>dacVolume</span>(left, right);</p>

  2411. 	<p class=desc>Adjust the digital output volume separately on left and

  2412. 		right channels.

  2413. 	</p>

  2414. 

  2415. 

  2416. 	<h3>Audio Processor</h3>

  2417. 

  2418. 	<p>The optional digital audio processor is capable of implementing

  2419. 		one or more of: automatic volume control, surround sound control,

  2420. 		bass enhancement, and tonal adjustments (either a

  2421. 		simple tone control, or a parametric equalizer, or a graphic equalizer),

  2422. 		in that order.

  2423. 	</p>

  2424. 	<p>These signal processing features are implemented in the SGTL5000 chip,

  2425. 		so they do not consume CPU time on Teensy. However, the order of

  2426. 		these processes is fixed in the hardware.

  2427. 	</p>

  2428. 	<p>It is good practice to mute the outputs before enabling or disabling

  2429. 	the Audio Processor, to avoid clicks or thumps.

  2430. 	</p>

  2431. 

  2432. 	<p class=func><span class=keyword>audioPreProcessorEnable</span>();</p>

  2433. 	<p class=desc>Enable the audio processor to pre-process the input

  2434. 		(from either line-level inputs or microphone) before it's sent

  2435. 		to Teensy by I2S.

  2436. 	</p>

  2437. 	<p class=func><span class=keyword>audioPostProcessorEnable</span>();</p>

  2438. 	<p class=desc>Enable the audio processor to post-process Teensy's

  2439. 		I2S output before it's turned into analog signals for the

  2440. 		headphones and/or line level outputs.

  2441. 	</p>

  2442. 	<p class=func><span class=keyword>audioProcessorDisable</span>();</p>

  2443. 	<p class=desc>Disable the audio processor.

  2444. 	</p>

  2445. 	<p class=func><span class=keyword>autoVolumeControl</span>(maxGain, response, hardLimit, threshold, attack, decay);</p>

  2446. 	<p class=desc>Configures the auto volume control, which is implemented as a compressor/expander

  2447. 	or hard limiter. 	<em>maxGain</em> is the maximum gain that can be applied for expanding, and

  2448. 	can take one of three values: 0 (0dB), 1 (6.0dB) and 2 (12dB). Values greater than 2 are treated

  2449. 	as 2. <em>response</em> controls the integration time for the compressor and can take

  2450. 	four values: 0 (0ms), 1 (25ms), 2 (50ms) or 3 (100ms). Larger values average the volume

  2451. 	over a longer time, allowing short-term peaks through.

  2452. 	</p>

  2453. 	<p class=desc>If <em>hardLimit</em> is 0, a 'soft

  2454. 	knee' compressor is used to progressively compress louder values which are near to or above the

  2455. 	threashold (the louder they are, the greater the compression). If it is 1, a hard compressor

  2456. 	is used (all values above the threashold are the same loudness). The <em>threashold</em> is specified

  2457. 	as a float in the range 0dBFS to -96dBFS, where -18dBFS is a typical value.

  2458. 	<em>attack</em> is a float controlling the rate of decrease in gain when the signal is over

  2459. 	threashold, in dB/s. <em>decay</em> controls how fast gain is restored once the level

  2460. 	drops below threashold, again in dB/s. It is typically set to a longer value than attack.

  2461. 	</p>

  2462. 	<p class=func><span class=keyword>autoVolumeEnable</span>();</p>

  2463. 	<p class=desc>Enables auto volume control, using the previously specified settings.

  2464. 	</p>

  2465. 	<p class=func><span class=keyword>autoVolumeDisable</span>();</p>

  2466. 	<p class=desc>Disables auto volume control.

  2467. 	</p>

  2468. 

  2469. 	<p class=func><span class=keyword>surroundSoundEnable</span>();</p>

  2470. 	<p class=desc>Enable virtual surround processing, to give a broader and

  2471. 	deeper stereo image (even with mono input).

  2472. 	</p>

  2473. 	<p class=func><span class=keyword>surroundSoundDisable</span>();</p>

  2474. 	<p class=desc>Disable virtual surround processing. Before disabling, ramp up

  2475. 	the width to maximum to avoid pops.

  2476. 	</p>

  2477. 	<p class=func><span class=keyword>surroundSound</span>(width);</p>

  2478. 	<p class=desc>Configures virtual surround width from 0 (mono) to 7 (widest).

  2479. 	</p>

  2480. 	<p class=func><span class=keyword>surroundSound</span>(width, select);</p>

  2481. 	<p class=desc>Configures virtual surround width from 0 (mono) to 7 (widest).

  2482. 	<em>select</em> may be set to 1 (disable), 2 (mono input) or 3 (stereo input).

  2483. 	</p>

  2484. 

  2485. 	<p class=func><span class=keyword>enhanceBassEnable</span>();</p>

  2486. 	<p class=desc>Enable bass enhancement. A mono, low-pass filtered copy of

  2487. 	the original stereo signal has bass levels boosted and is then mixed back into

  2488. 	the stereo signal, which is then optionally high pass filtered (to remove

  2489. 	inaudible subsonic frequencies).

  2490. 	</p>

  2491. 	<p class=func><span class=keyword>enhanceBassDisable</span>();</p>

  2492. 	<p class=desc>Disable bass enhancement. Before disabling, ramp down the bass

  2493. 	enhancement level to zero.

  2494. 	</p>

  2495. 	<p class=func><span class=keyword>enhanceBass</span>(lr_lev, bass_lev);</p>

  2496. 	<p class=desc>Configures the bass enhancement by setting the levels of the

  2497. 	original stereo signal and the bass-enhanced mono level which will be mixed together.

  2498. 	There is no high-pass filter.

  2499. 	</p>

  2500. 	<p  class=desc>When changing bass level, call this function repeatedly to ramp up or down the bass in

  2501. 	steps of 0.5dB, to avoid pops.

  2502. 	</p>

  2503. 	<p class=func><span class=keyword>enhanceBass</span>(lr_lev, bass_lev, hpf_bypass, cutoff);</p>

  2504. 	<p class=desc>Configures the bass enhancement by setting the levels of the

  2505. 	original stereo signal and the bass-enhanced mono level which will be mixed together.

  2506. 	The high-pass filter may be enabled (0) or bypassed (1). The cutoff frequency is specified

  2507. 	as follows:

  2508. 	</p>

  2509. 	<pre class="desc">

  2510. value  frequency

  2511.  0      80Hz

  2512.  1     100Hz

  2513.  2     125Hz

  2514.  3     150Hz

  2515.  4     175Hz

  2516.  5     200Hz

  2517.  6     225Hz

  2518. </pre>

  2519. 	<p  class=desc>When changing bass level, call this function repeatedly to ramp up or down the bass in

  2520. 	steps of 0.5dB, to avoid pops.

  2521. 	</p>

  2522. 

  2523. 	<p class=func><span class=keyword>eqSelect</span>(n);</p>

  2524. 	<p class=desc>Selects the type of frequency control, where <em>n</em> is

  2525. 	one of</p>

  2526. 	<p class=desc><b>FLAT_FREQUENCY (0)</b><br>

  2527.     Equalizers and tone controls disabled, flat frequency response.</p>

  2528.     <p class=desc><b>PARAMETRIC_EQUALIZER (1)</b><br>

  2529.     Enables the 7-band parametric equalizer, thus disabling the

  2530. 	tone controls and graphic equalizer.</p>

  2531.     <p class=desc><b>TONE_CONTROLS (2)</b><br>

  2532.     Enables bass and treble tone controls, disabling the parametric

  2533. 	equalization and graphic equalizer.</p>

  2534.     <p class=desc><b>GRAPHIC_EQUALIZER (3)</b><br>

  2535.     Enables the five-band graphic equalizer, disabling the parametric

  2536. 	equalization and tone controls.</p>

  2537. 

  2538. 

  2539. 	<p class=func><span class=keyword>eqBands</span>(bass, treble);</p>

  2540. 	<p class=desc>Configures bass and treble tone controls, which are

  2541. 	implemented as one second order low pass filter (bass) in parallel with

  2542. 	one second order high pass filter (treble).

  2543. 	</p>

  2544. 	<p class=desc>When changing bass or treble level, call this function repeatedly to ramp

  2545. 	up or down the level in steps of 0.04 (=0.5dB) or so, to avoid pops.

  2546. 	</p>

  2547. 	<p class=func><span class=keyword>eqBands</span>(bass, mid_bass, midrange, mid_treble, treble);</p>

  2548. 	<p class=desc>Configures the graphic equalizer. It is implemented by five parallel,

  2549. 	second order biquad filters with fixed frequencies of 115Hz, 330Hz, 990Hz, 3kHz,

  2550. 	and 9.9kHz. Each band has a range of adjustment from 1.00 (+12dB) to -1.00 (-11.75dB).

  2551. 	</p>

  2552. 	<p class=func><span class=keyword>eqBand</span>(bandNum, n);</p>

  2553. 	<p class=desc>Configures the gain or cut on one band in the graphic equalizer.

  2554. 	<em>bandnum</em> can range from 1 to 5; <em>n</em> is a float in the range 1.00 to -1.00.

  2555. 	</p>

  2556. 	<p  class=desc>When changing a band, call this function repeatedly to ramp up the gain in steps of 0.5dB,

  2557. 	to avoid pops.

  2558. 	</p>

  2559. 

  2560. 	<p class=func><span class=keyword>eqFilter</span>(filterNum, filterParameters);</p>

  2561. 	<p class=desc>Configurs the parametric equalizer. The number of filters (1 to 7)

  2562. 	is specified along with  a pointer to an array of filter coefficients.

  2563. 	The parametric equalizer is implemented using 7 cascaded, second order bi-quad

  2564. 	filters whose frequencies, gain, and Q may be freely configured, but each filter

  2565. 	can only be specified as a set of filter coefficients.

  2566. 	</p>

  2567. 	<p class=func><span class=keyword>eqFilterCount</span>(n);</p>

  2568. 	<p class=desc>Enables zero or more of the already enabled parametric filters.

  2569. 	</p>

  2570. 

  2571. 	<h3>Examples</h3>

  2572. 	<p>Nearly all of the library's examples use this object.  These

  2573. 		examples demonstrate its special features.

  2574. 	</p>

  2575. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; PassThroughStereo

  2576. 	</p>

  2577. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; SGTL5000 &gt; dap_bass_enhance

  2578. 	</p>

  2579. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; SGTL5000 &gt; dap_avc_agc

  2580. 	</p>

  2581. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; SGTL5000 &gt; balanceDAC

  2582. 	</p>

  2583. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; SGTL5000 &gt; balanceHP

  2584. 	</p>

  2585. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; SGTL5000 &gt; CalcBiquadToneControlDAP

  2586. 	</p>

  2587. 	<h3>Notes</h3>

  2588. 	<p>TODO: add example with rock/classical/speech presets, where rock uses bass boost

  2589. 	and surround enhancement while speech uses bandpass filtering and auto volume control

  2590. 	compression.

  2591. 	</p>

  2592. 	<p>TODO: add example with two analogRead pots for bass and treble to demonstrate ramping.

  2593. 	</p>

  2594. </script>

  2595. <script type="text/x-red" data-template-name="AudioControlSGTL5000">

  2596. 	<div class="form-row">

  2597. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2598. 		<input type="text" id="node-input-name" placeholder="Name">

  2599. 	</div>

  2600. </script>

  2601. 

  2602. <script type="text/x-red" data-help-name="AudioControlWM8731">

  2603. 	<h3>Summary</h3>

  2604. 	<p>Control a WM8731 chip in slave mode, where it receives all clocks from Teensy</p>

  2605. 	<h3>Audio Connections</h3>

  2606. 	<p>This object has no audio inputs or outputs.  Separate i2s objects

  2607. 		are used to send and receive audio data.  I2S master mode objects

  2608. 		must be used, since this control object configures the WM8731 into

  2609. 		slave mode.

  2610. 	</p>

  2611. 	<h3>Functions</h3>

  2612. 	<p class=func><span class=keyword>enable</span>();</p>

  2613. 	<p class=desc>blah blah blah blah

  2614. 	</p>

  2615. 	<p class=func><span class=keyword>disable</span>();</p>

  2616. 	<p class=desc>not implemented

  2617. 	</p>

  2618. 	<p class=func><span class=keyword>volume</span>(level);</p>

  2619. 	<p class=desc>blah blah blah blah

  2620. 	</p>

  2621. 	<p class=func><span class=keyword>inputLevel</span>(level);</p>

  2622. 	<p class=desc>not implemented

  2623. 	</p>

  2624. 	<p class=func><span class=keyword>inputSelect</span>(input);</p>

  2625. 	<p class=desc>not implemented

  2626. 	</p>

  2627. 	<!--

  2628. <h3>Examples</h3>

  2629. 	<p class=exam>File &gt; Examples &gt; Audio &gt;

  2630. 	</p>

  2631. -->

  2632. 	<h3>Notes</h3>

  2633. 	<p></p>

  2634. </script>

  2635. <script type="text/x-red" data-template-name="AudioControlWM8731">

  2636. 	<div class="form-row">

  2637. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2638. 		<input type="text" id="node-input-name" placeholder="Name">

  2639. 	</div>

  2640. </script>

  2641. 

  2642. <script type="text/x-red" data-help-name="AudioControlWM8731master">

  2643. 	<h3>Summary</h3>

  2644. 	<p>Control a WM8731 chip in master mode, where it controls all I2S timing.</p>

  2645. 	<h3>Audio Connections</h3>

  2646. 	<p>This object has no audio inputs or outputs.  Separate i2s objects

  2647. 		are used to send and receive audio data.  I2S slave mode objects

  2648. 		must be used, since this control object configures the WM8731 into

  2649. 		master mode.

  2650. 	</p>

  2651. 	<h3>Functions</h3>

  2652. 	<p class=func><span class=keyword>enable</span>();</p>

  2653. 	<p class=desc>blah blah blah blah

  2654. 	</p>

  2655. 	<p class=func><span class=keyword>disable</span>();</p>

  2656. 	<p class=desc>not implemented

  2657. 	</p>

  2658. 	<p class=func><span class=keyword>volume</span>(level);</p>

  2659. 	<p class=desc>blah blah blah blah

  2660. 	</p>

  2661. 	<p class=func><span class=keyword>inputLevel</span>(level);</p>

  2662. 	<p class=desc>not implemented

  2663. 	</p>

  2664. 	<p class=func><span class=keyword>inputSelect</span>(input);</p>

  2665. 	<p class=desc>not implemented

  2666. 	</p>

  2667. 	<h3>Examples</h3>

  2668. 	<p class=exam>File &gt; Examples &gt; Audio &gt; HardwareTesting &gt; WM8731MikroSine

  2669. 	</p>

  2670. 	<h3>Notes</h3>

  2671. 	<p></p>

  2672. </script>

  2673. <script type="text/x-red" data-template-name="AudioControlWM8731master">

  2674. 	<div class="form-row">

  2675. 		<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>

  2676. 		<input type="text" id="node-input-name" placeholder="Name">

  2677. 	</div>

  2678. </script>

  2679. 

  2680. </body>

  2681. </html>