1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2<html>
3
4<head>
5<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
6<meta name="GENERATOR" content="Microsoft FrontPage 3.0">
7<meta http-equiv="Content-Style-Type" content="text/css">
8<link rel="stylesheet" type="text/css" href="../CSS/revolution.css">
9<title>VIGetVSyncTimingTest</title>
10</head>
11
12<body>
13
14<h1 align="left">VIGetVSyncTimingTest</h1>
15
16<h2>C Specification</h2>
17
18<dl>
19<dd><pre><code>#include &lt;revolution/vi.h&gt;</code></pre>
20  </dd>
21<dd><pre><code>u32 VIGetVSyncTimingTest(void)</code></pre>
22  </dd>
23</dl>
24
25<h2>Arguments</h2>
26
27<p>None.</p>
28
29<h2>Return Values</h2>
30
31<p>Returns the number of times the VI retrace interrupt was delayed.</p>
32
33<h2>Description</h2>
34
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.
36</p>
37
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 <code><a href="VISetVSyncTimingTest.html">VISetVSyncTimingTest</a></code>.
40</p>
41
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. 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.
44</p>
45
46
47<p>
48This function always returns non-zero because the VI interrupt timing is slightly delayed when debugging using Code Warrior's step execution feature. We recommend that you test software under normal execution conditions when testing progressive display.
49</p>
50
51
52<h2>See Also</h2>
53
54<p><code><a href="VISetVSyncTimingTest.html">VISetVSyncTimingTest</a></code></p>
55
56
57<h2>Revision History</h2>
58
59<p>
602006/10/18 Added a caution about Code Warrior's step execution.<br>2006/06/06 Initial version.
61</p>
62<hr>
63<P>CONFIDENTIAL</p>
64</BODY>
65</HTML>
66