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="IBM WebSphere Studio Homepage Builder Version 8.0.0.0 for Windows"> 7<META http-equiv="Content-Style-Type" content="text/css"> 8<title>MIC_StartLimitedSampling</title> 9<LINK rel="stylesheet" href="../../css/nitro.css" type="text/css"> 10</head> 11 12<body> 13 14<h1 align="left">MIC_StartLimitedSampling <img src="../../image/TWL.gif"></h1> 15 16<h2>Syntax</h2> 17<dl> 18 <dd> 19<CODE>#include <twl/spi.h></CODE><BR> 20 <PRE><CODE><A href="MICResult.html">MICResult</A> MIC_StartLimitedSampling( 21 const <CODE><A href="MICAutoParam.html">MICAutoParam</A></CODE>* param );</CODE></PRE> 22 </dd> 23</dl> 24 25<h2>Arguments</h2> 26<TABLE border="1" width="100%"> 27 <TBODY> 28 <TR> 29 <TD width="300"><em><strong><font face="Courier New">param</font></strong></em></TD> 30 <TD width="700">Specifies a pointer to a <CODE><A href="MICAutoParam.html">MICAutoParam</A></CODE>-type auto-sampling settings structure.</TD> 31 </TR> 32 </TBODY> 33</TABLE> 34 35<h2>Return Values</h2> 36<P> 37Returns the processing result as a <CODE><A href="MICResult.html">MICResult</A></CODE> enumerated type. Returns <CODE>MIC_RESULT_SUCCESS</CODE> if processing completed successfully; returns some other value if the process failed. 38</P> 39 40<H2>Description</H2> 41<P>Starts frequency-limited microphone auto-sampling.<BR>This function issues a request to the ARM7 to start frequency-limited auto-sampling, waits for the ARM7 to respond, and returns the processing result. This is a synchronous version of the <CODE><A href="MIC_StartLimitedSamplingAsync.html">MIC_StartLimitedSamplingAsync</A></CODE> function. Where the input volume falls outside the minimum or maximum value, the sampling data will be clamped. 42</P> 43<P> 44Frequency-limited auto-sampling differs from normal auto-sampling in that the hardware does the actual sampling. As a result, stable sampling can be performed at precise cycles; also, by relaxing the CPU burden on the ARM7, effects of sampling on wireless communications and other I/O will be reduced. On the other hand, sampling cannot be performed at frequencies that are unsupported by the hardware. The following sampling frequencies can be specified for <CODE>param</CODE> <CODE>->rate</CODE>, but the frequencies that can be specified at a given time depend on the sound master frequency settings and thus are further limited to four of the following. A value of <CODE>MIC_RESULT_ILLEGAL_PARAMETER</CODE> will be returned if one of the limited frequencies is not specified. 45</P> 46<TABLE border="1" width="100%"> 47 <TBODY> 48 <TR> 49 <TH width="20%"><center>Sound master frequency</center></TD> 50 <TH width="40%"><center>Settable frequency</center></TD> 51 <TH width="40%"><center>Description</center></TD> 52 </TR> 53 <TR> 54 <TD rowspan="4">32.73kHz</TD> 55 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_32730</font></strong></em></TD> 56 <TD>32.73kHz (1/1 of the master frequency)</TD> 57 </TR> 58 <TR> 59 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_16360</font></strong></em></TD> 60 <TD>16.36kHz (1/2 of the master frequency)</TD> 61 </TR> 62 <TR> 63 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_10910</font></strong></em></TD> 64 <TD>10.91kHz (1/3 of the master frequency)</TD> 65 </TR> 66 <TR> 67 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_8180</font></strong></em></TD> 68 <TD>8.18kHz (1/4 of the master frequency)</TD> 69 </TR> 70 <TR> 71 <TD rowspan="4">47.61kHz</TD> 72 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_47610</font></strong></em></TD> 73 <TD>47.61kHz (1/1 of the master frequency)</TD> 74 </TR> 75 <TR> 76 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_23810</font></strong></em></TD> 77 <TD>23.81kHz (1/2 of the master frequency)</TD> 78 </TR> 79 <TR> 80 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_15870</font></strong></em></TD> 81 <TD>15.87kHz (1/3 of the master frequency)</TD> 82 </TR> 83 <TR> 84 <TD><em><strong><font face="Courier New">MIC_SAMPLING_RATE_11900</font></strong></em></TD> 85 <TD>11.90kHz (1/4 of the master frequency)</TD> 86 </TR> 87 </TBODY> 88</TABLE> 89 90<H2>Note</H2> 91<P> 92<FONT color=red>This function waits for a PXI interrupt for synchronization purposes. Do not call it when PXI interrupts are prohibited.<BR> <BR>Because frequency-limited auto-sampling cannot be performed on the NITRO platform or when the CODEC is running in CODEC-DS mode, this function will instead internally call the <CODE><A href="MIC_StartAutoSampling.html">MIC_StartAutoSampling</A></CODE> auto-sampling control function.</FONT> 93</P> 94<P><FONT color=red>It has been confirmed that slight hardware noise is mixed with the microphone input on the TWL console. See <A href="./about_HardwareNoise.html">here</A> for a workaround.</FONT></P> 95<H2>See Also</H2> 96<P> 97<CODE><A href="MIC_StartLimitedSamplingAsync.html">MIC_StartLimitedSamplingAsync</A>, <A href="MIC_StopLimitedSampling.html">MIC_StopLimitedSampling</A>, <A href="MIC_AdjustLimitedSampling.html">MIC_AdjustLimitedSampling</A></CODE> 98</P> 99 100<H2>Revision History</H2> 101<P> 1022008/01/09 Added a note about the difference in behavior with CODEC mode. <BR>2007/11/17 Initial version.<BR> 103</P> 104<hr><p>CONFIDENTIAL</p></body> 105</html> 106
