1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2<HTML> 3<HEAD> 4<META http-equiv="Content-Type" content="text/html; charset=windows-1252"> 5<META name="GENERATOR" content="IBM WebSphere Studio Homepage Builder Version 7.0.1.0 for Windows"> 6<META http-equiv="Content-Style-Type" content="text/css"> 7<TITLE>PM_SetBackLight*</TITLE> 8<LINK rel="stylesheet" href="../../css/nitro.css" type="text/css"> 9</HEAD> 10<BODY> 11<H1 align="left">PM_SetBackLight* <IMG src="../../image/NTR.gif" width="24" height="12" border="0" align="middle"><IMG src="../../image/TWL.gif" width="24" height="12" border="0" align="middle"></H1> 12<H2>Syntax</H2> 13<DL> 14 <DD> 15 <PRE><CODE>#include <nitro/spi.h></CODE></PRE> 16 <PRE><CODE>u32 PM_SetBackLight( PMLCDTarget target, PMBackLightSwitch sw ); 17 18u32 PM_SetBackLightAsync( PMLCDTarget target, PMBackLightSwitch sw, PMCallback callback, void* arg ); 19 </CODE></PRE> 20</DL> 21<H2>Arguments</H2> 22<TABLE border="1" width="100%"> 23 <TBODY> 24 <TR> 25<TD width="13%"><SPAN class="argument">target</SPAN></TD> 26<TD width="87%">Screen that is the target of operation.</TD> 27 </TR> 28 <TR> 29<TD width="13%"><SPAN class="argument">sw</SPAN></TD> 30<TD width="87%">Backlight switch.</TD> 31 </TR> 32 <TR> 33<TD><SPAN class="argument">callback</SPAN></TD> 34<TD>Callback that is called when the command finishes.</TD> 35 </TR> 36 <TR> 37<TD><SPAN class="argument">arg</SPAN></TD> 38<TD>Argument that is used when calling the callback.</TD> 39 </TR> 40 </TBODY> 41</TABLE> 42<H2>Return Values</H2> 43<P>If <CODE>PM_RESULT_SUCCESS</CODE>, the command execution has succeeded (for synchronous functions), or the command was successfully sent to the ARM7 processor (for asynchronous functions).</P> 44<P>If <CODE>PM_INVALID_COMMAND</CODE>, the argument that was passed is invalid.</P> 45<P>If <CODE>PM_RESULT_BUSY</CODE>, the SPI was occupied by other processing and unable to process this function.</P> 46<H2>Description</H2> 47<P>Toggles the specified screen's backlight switch.</P> 48<P>The <SPAN class="argument">target</SPAN> argument is a <code>PMLCDTarget</code> enumerator type that can contain either one of the following values. 49</P> 50<TABLE border="1"> 51 <TBODY> 52 <TR> 53<TH>Value of <SPAN class="argument">target</SPAN></TH> 54<TH>Targeted LCD</TH> 55 </TR> 56 <TR> 57<TD><CODE>PM_LCD_TOP</CODE></TD> 58<TD>top screen</TD> 59 </TR> 60 <TR> 61<TD><CODE>PM_LCD_BOTTOM</CODE></TD> 62<TD>bottom screen</TD> 63 </TR> 64 <TR> 65<TD><CODE>PM_LCD_ALL</CODE></TD> 66<TD>top and bottom screens </TD> 67 </TR> 68 </TBODY> 69</TABLE> 70<P><BR> The <SPAN class="argument">sw</SPAN> argument is a <code>PMBackLightSwitch</code> enumerator type value that specifies one of the following values. 71</P> 72<TABLE border="1"> 73 <TBODY> 74 <TR> 75<TH>Value of <SPAN class="argument">sw</SPAN></TH> 76<TH>Backlight Operation</TH> 77 </TR> 78 <TR> 79<TD><CODE>PM_BACKLIGHT_OFF</CODE></TD> 80<TD>Turns the backlight OFF. </TD> 81 </TR> 82 <TR> 83<TD><CODE>PM_BACKLIGHT_ON</CODE></TD> 84<TD>Turns the backlight ON.</TD> 85 </TR> 86 </TBODY> 87</TABLE> 88<P><BR> This function performs the operation that is specified by <SPAN class="argument">sw</SPAN> on the screen that is specified by the <SPAN class="argument">target</SPAN> argument.</P> 89<P>Before you use this function, initialize the PM library with the <A href="PM_Init.html"><CODE>PM_Init</CODE></A> function. The <code>PM_Init</code> function has to be called only once. Also, when you call the <a href="../../os/init/OS_Init.html"><code>OS_Init</code></a> function, there is no need to call the <a href="PM_Init.html"><code>PM_Init</code></a> function separately because it is called from within the <code>OS_Init</code> function.</P> 90<P><FONT color="#ff0000">This function can be used from an interrupt handler. This function cannot be used in interrupt-prohibited states other than interrupt handlers.</FONT></P> 91<P><B>Asynchronous Functions</B></P> 92<P>This function uses PXI to send the command that performs the corresponding operation in the ARM7 processor. The ARM7 side that receives that command is executed by operating the PMIC. Therefore, this function may not operate instantly after you call it. A synchronous function that waits for the operation to finish, as well as an asynchronous function that only sends commands to the ARM7, are provided. Use either of the functions depending on your operational requirements. (The asynchronous function has "Async" appended to the function name.)</P> 93<P>When an asynchronous function is called, the specified <CODE>callback</CODE> is called when processing on the ARM7 side finishes. The callback type <CODE>PMCallback</CODE> is defined by: </P> 94<BLOCKQUOTE> <CODE><code>typedef void ( *PMCallback )( u32 result, void* arg )</code>;</CODE></BLOCKQUOTE> 95<P> This callback is called from within the PXI interrupt handler.</P> 96<P>The callback's first argument, <CODE>result</CODE>, indicates the result of the command. This is either <code>PM_RESULT_SUCCESS</code> or <code>PM_RESULT_BUSY</code>. The second argument in the callback returns the value <CODE>arg</CODE>.</P> 97<P><B>About <CODE>PM_RESULT_BUSY</CODE></B></P> 98<P>The SPI is used for various other processes besides power management. If you call this function while another process is using it, this function sends a command to the ARM7; there, the SPI is determined to be BUSY, and <CODE>PM_RESULT_BUSY</CODE> is notified to the ARM9 without actually processing this function. Likewise, if you call this function while another PM process is running, that fact is determined on the ARM9 side and this function returns <CODE>PM_RESULT_BUSY</CODE>. (In this case, the determination is made before notification is sent to the ARM7.)</P> 99<P>Accordingly, if you want to make certain that this function will succeed, make it loop until it succeeds as shown below. (This example does not take into account mistakes such as wrong arguments.)</P> 100<BLOCKQUOTE style="background-color:#ffffcc"><B>Example</B><BR> <CODE>while( PPM_SetBackLight( ... ) != PM_RESULT_SUCCESS )<BR> {<BR> }</CODE></BLOCKQUOTE> 101<P>When using the <CODE>Async</CODE> version of this function, you could do this with code similar to the following.</P> 102<BLOCKQUOTE style="background-color:#ffffcc"><B>Example</B><CODE><BR> void setResult( u32 result, void* arg )<BR> {<BR> if ( arg )<BR> {<BR> *(u32*)arg = result;<BR> }<BR> }<BR> <BR> while(1)<BR> {<BR> volatile u32 result = PM_RESULT_NONE; //A value that will not be returned<BR> <BR> while ( PM_SetBackLightAsync(..., setResult, (void*)&result ) != PM_RESULT_SUCCESS )<BR> {<BR> }<BR> <BR> // Some other process<BR> otherProcess();<BR> <BR> // Wait for completion<BR> while( result == PM_RESULT_NONE )<BR> {<BR> }<BR> <BR> // Exit the loop on success<BR> if ( result == PM_RESULT_SUCCESS )<BR> {<BR> break;<BR> }<BR> }</CODE></BLOCKQUOTE> 103<H2>Internal Operation</H2> 104<P>Operates the <CODE>PMIC_CTL</CODE> value of the PMIC register.</P> 105<H2>See Also</H2> 106<P><A href="PM_Init.html"><CODE>PM_Init</CODE></A><BR> <A href="PM_GetBackLight.html"><CODE>PM_GetBackLight</CODE></A></P> 107<H2>Revision History</H2> 108<P>2008/08/23 Ended the use of <CODE>PM_RESULT_ERROR</CODE> and elaborated on <CODE>PM_RESULT_BUSY</CODE>.<BR> 2005/07/07 Elaborated on the <CODE>PM_RESULT_ERROR</CODE> return value.<BR> 2005/06/02 Clarified the origin of the call to the callback.<BR> 2004/08/04 Initial version.</P> 109<hr><p>CONFIDENTIAL</p></body> 110</HTML>
