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    <p>According to the <a href="http://www.mathworks.com/products/daq/supportedio14004.html" rel="nofollow noreferrer">Supported Hardware documentation</a>, version 2.8 or greater of the <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/daq_product_page.html" rel="nofollow noreferrer">Data Acquisition Toolbox</a> is needed to support a Measurement Computing USB-1024HLS device. Assuming you have version 2.8 or newer, the following should come close to a solution for you...</p> <p>The first step would be to get the hardware ID for the device. The function <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/daqhwinfo.html" rel="nofollow noreferrer">DAQHWINFO</a> should help with this:</p> <pre><code>deviceInfo = daqhwinfo('mcc'); </code></pre> <p>The hardware ID gotten from the structure <strong>deviceInfo</strong> can then be used to create a Digital I/O Object (DIO) using the <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/digitalio.html" rel="nofollow noreferrer">DIGITALIO</a> function:</p> <pre><code>dio = digitalio('mcc',hardwareID); </code></pre> <p>Next, you have to add two output lines (for a clock signal and a pulse-width modulation (PWM) signal) using <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/addline.html" rel="nofollow noreferrer">ADDLINE</a>:</p> <pre><code>addline(dio,0:1,'out'); </code></pre> <p>Then, you have to set a few DIO properties.</p> <pre><code>set(dio,'TimerPeriod',0.000002); % i.e. 500 kHz set(dio,'TimerFcn',@update_outputs); </code></pre> <p>The function <strong>update_outputs</strong> is called once every timer period and should set the output pins to the appropriate values. The <a href="http://en.wikipedia.org/wiki/Clock_signal" rel="nofollow noreferrer">clock signal</a> is simply going to switch back and forth between 0 and 1 every timer period. The <a href="http://en.wikipedia.org/wiki/Pulse-width_modulation" rel="nofollow noreferrer">PWM signal</a> will likely alternate between 0 and 1 as well, but it will not change every timer period, remaining in each state for a set amount of time based upon the sort of pulse-width modulation you want. Here's what your <strong>update_outputs</strong> function may end up looking like:</p> <pre><code>function update_outputs(obj,event) currentValues = getvalue(obj); clockValue = ~currentValues(1); pwmValue = pwm_compute(); putvalue(obj,[clockValue pwmValue]); end </code></pre> <p>Note that this uses <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/putvalue.html" rel="nofollow noreferrer">PUTVALUE</a> and <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/getvalue.html" rel="nofollow noreferrer">GETVALUE</a> to set/get the values of the output pins. You will have to write the function <strong>pwm_compute</strong> such that it computes a new PWM value for each time period. Since <strong>pwm_compute</strong> will likely have to know how many values have been output already (i.e. how many times it has already been called), you can track that using a <a href="http://www.mathworks.com/access/helpdesk/help/techdoc/ref/persistent.html" rel="nofollow noreferrer">persistent variable</a>:</p> <pre><code>function newValue = pwm_compute persistent nValues; if isempty(nValues) nValues = 0; else nValues = nValues+1; end ... % Compute the new value for the (nValues+1) time period ... end </code></pre> <p>This is just one possible solution. You could potentially precompute the PWM signal and pull the value for each timer period from a vector or data file, or you could potentially use the <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/timerfcn.html" rel="nofollow noreferrer"><strong>event</strong> data structure</a> passed to <strong>update_outputs</strong> to get the time of the timer event (relative to the DIO timer start, I believe).</p> <p>Finally, you have to start the DIO:</p> <pre><code>start(dio); </code></pre> <p>...and, once you're finished using it, delete it and clear it from memory:</p> <pre><code>delete(dio); clear dio; </code></pre> <h2>One potential stumbling block...</h2> <p>Generating a 500 kHz signal could be difficult. It's such a high frequency that you <em>may</em> run into problems, specifically with the 'TimerFcn', which is called once every timer period. If the 'TimerFcn' takes longer than 0.000002 seconds to run, <a href="http://www.mathworks.com/access/helpdesk/help/toolbox/daq/timerfcn.html" rel="nofollow noreferrer">some timer events may not be processed</a>, leading to an output that is actually of a lower frequency. I have a feeling you may have to use a lower signal frequency for things to work properly, but I could be wrong. =)</p>
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    1. COAccording to http://www.mathworks.com/access/helpdesk/help/toolbox/daq/index.html?/access/helpdesk/help/toolbox/daq/daq_product_page.html, the newest version of Data Acquisition Toolbox is 2.14, but I have still managed to communicate to my DAQ somehow. I just haven't implemented the clock signal yet (that you have suggested). It would be great if I can hear your thoughts about the Data Acquisition Toolbox version from what you have read. Thanks for the effort.
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    2. COIf you have the newest version, you're good. It's "two-point-fourteen" as opposed to "two-point-one-four", if that was the confusion (i.e. it is 6 better than "two-point-eight"). =)
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