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9<title>VIGetVSyncTimingTest</title>
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14<h1 align="left">VIGetVSyncTimingTest</h1>
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16<h2>C Specification</h2>
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18<dl>
19<dd><pre><code>#include &lt;revolution/vi.h&gt;</code></pre>
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21<dd><pre><code>u32 VIGetVSyncTimingTest(void)</code></pre>
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25<h2>Arguments</h2>
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27<p>None.</p>
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29<h2>Return Values</h2>
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31<p>Returns the number of times the VI retrace interrupt was delayed. </p>
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33<h2>Description</h2>
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35<p>This function is primarily used to test whether the switch from interlace to progressive mode occurred correctly. To switch modes, execute <code><a href="VIGetVSyncTimingTest.html">VISetVSyncTimingTest</a></code> anytime during interlaced display and then execute this function after the display switches to progressive mode.
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38<p>
39This function returns the number of times that VI retrace interrupt timing was delayed since <code><a href="VISetVSyncTimingTest.html">VISetVSyncTimingTest</a></code> executed. Then stop checking the VI retrace interrupt timing that executed for each field. So, to get the correct number of interrupt delays, always use this function together with <code><a href="VISetVSyncTimingTest.html">VISetVSyncTimingTest</a></code>.
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42<p>
43Although the progressive display shown on the TV screen sometimes appears correct even though the return value of this function is non-zero, this is only a case of the display occasionally coming out correctly. Therefore, be sure the return value of this function is always 0. If the return value is not 0, check if a long period where interrupts are disabled was set within the program.
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49<h2>See Also</h2>
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51<p><code><a href="VISetVSyncTimingTest.html">VISetVSyncTimingTest</a></code></p>
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53
54<h2>Revision History</h2>
55
56<p>06/06/2006 Initial version.</p>
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