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<concept id="GUID-7E3BBB18-3113-4312-AD91-897DE87C58BF" xml:lang="en"><title>SDIO
PSU Implementation Tutorial</title><shortdesc>How to implement the platform-specific class for the Power Supply
Unit of an SDIO-based hardware component.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>The Power Supply Unit (PSU) functionality is provided by the <xref href="GUID-9BF2FEAC-F6B8-3071-A4AB-976E33354F1D.dita"><apiname>DSDIOPsu</apiname></xref> class.
To enable power control in the SDIO Controller, you must implement the <codeph>PsuInfo()</codeph> function
in the derived class of the <xref href="GUID-9BF2FEAC-F6B8-3071-A4AB-976E33354F1D.dita"><apiname>DSDIOPsu</apiname></xref> class. </p>
<p>The <codeph>iNotLockedTimeOut</codeph> variable
is used by the "card not locked" functionality and the value is tied to the
reference board inactivity time-out. The <codeph>iInactivityTimeOut</codeph> variable
is used to set a time-out value for the sleep mode of the SDIO cards. </p>
<example><p><codeblock xml:space="preserve">void DMySdioPsu::PsuInfo(TPBusPsuInfo&amp; anInfo)
	{
	...
	// Only for SDIO
	anInfo.iNotLockedTimeOut = 5;    // Power down after 5 seconds of non-use (no clients registered)
	anInfo.iInactivityTimeOut = 1;	// Enter Sleep mode within 1 Second of inactivity (clients registered)
	...
	return;
	}
</codeblock></p></example>
</conbody></concept>