--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/PDK/Source/GUID-0E5A241A-19F5-5754-B454-45747A8D80E1.dita	Fri Jan 22 18:26:19 2010 +0000
@@ -0,0 +1,101 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-0E5A241A-19F5-5754-B454-45747A8D80E1" xml:lang="en"><title>SD Card
+Overview</title><shortdesc>Description of SD card features available to application developers
+and what a device creator must write to provide SD card support.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>SD memory cards (Secure Digital memory cards) are flash-based memory cards
+designed to provide secure high capacity data storage. </p>
+<p>The SD controller supports the <i>Simplified SD Physical layer specification
+version 2.0</i> which is owned by the <i>SD Card Association</i> and the <i>SD
+Group</i>. </p>
+<p>The SD memory card standard is defined to be protocol forward compatible
+with MultiMediaCard version 2.11 and it is possible for a MultiMediaCard to
+be inserted into an SD memory card socket and host systems to support both
+types of card. </p>
+<section id="GUID-AA07DD5E-0DB7-4B0C-8475-7A36E9F600CA"><title>Purpose</title> <p>SD cards are based on MultiMediaCards (MMC)
+but with additional functionality detailed below. Symbian platform support
+for SD is built on top of the MMC support. This section describes the additional
+functionality available to applications using SD cards. This section also
+describes the additional work required to support SD cards. </p> </section>
+<section id="GUID-E53DD689-D81A-44A1-870B-3ECE796B86F1"><title>Required background</title> <p>You should be familiar with
+the following: </p> <ul>
+<li id="GUID-390334A3-BC5D-5E90-A114-E44C724DE63B"><p><xref href="GUID-79B2CF91-FB95-5E7C-81CC-235A6A660D88.dita">MMC
+Controller</xref>  </p> </li>
+<li id="GUID-C1841C2F-9D08-59D4-8183-6B1179D33763"><p> <xref href="http://www.sdcard.org/developers/tech/sdcard/pls/" scope="external">SD Simplified Specification</xref>  </p> </li>
+</ul> </section>
+<section id="GUID-EC87FA96-C124-43A0-A173-510B8A73FE98"><title>Key concepts and terms</title> <p>An SD card is very similar
+to a MultiMediaCard (MMC) but with additional features to support high capacity,
+high speed, secure storage. </p> <p>As SD cards are very similar to MMC, you
+should read the section on <xref href="GUID-BE6AFD38-5952-537F-848C-C76C8F5FA9BF.dita">MMC
+Controller Architecture</xref> before reading the <xref href="GUID-114A23CF-BF8B-54F5-8AF6-FEF007891884.dita">SD
+Controller</xref> documentation. </p> </section>
+<section id="GUID-C800CBB8-057F-494B-B0B8-95C6DBE13006"><title>Architecture</title> <p>SD support is divided into two parts,
+the Platform Independent Layer (PIL) and the Platform Specific Layer (PSL). </p> <p>The
+PIL is implemented as an E32 peripheral bus controller - <filepath>EPBUSSD.DLL</filepath> which
+is a kernel extension and extends the functionality of the matching MMC library <filepath>EPBUSM.DLL</filepath>.
+The <filepath>EPBUSSD.DLL</filepath> library consists of a generic peripheral
+bus layer, which is identical to the one used for MMC, and a generic SD card
+layer. The SD card layer is a superset of the MMC layer and derives additional
+classes for SD cards from the MMC classes. These derived classes support the
+additional features found in an SD card. </p> <p>The additional functionality
+available in an SD card includes: </p> <ul>
+<li id="GUID-832D06C4-3EA0-552B-8002-3CB9CB281BE7"><p>an optional 4-bit wide
+data bus </p> </li>
+<li id="GUID-04D41D5C-B0E4-51FE-96D8-561EADE20D11"><p>individual SD card addressing </p> </li>
+<li id="GUID-B1EA016E-F935-5590-9446-86B0C4825B51"><p>support for card capacities
+up to 32Gb </p> </li>
+<li id="GUID-741CF2BF-08A3-50C1-B3B8-DF616C9C5B28"><p>revised erase ranges
+allowing smaller ranges to be erased from an SD card </p> </li>
+<li id="GUID-BCEA1C92-84C5-5571-9AE0-BA7AC76B3003"><p>optional secure data
+area - Symbian Platform does not provide support for using the secure data
+area on an SD card. </p> </li>
+</ul> <p>You, as a device creator, will need to write the PSL. Implementing
+the PSL is described in <xref href="GUID-E194A923-99E7-5DC1-BB78-D050A4793A60.dita">SD
+Controller PSL Implementation</xref>. </p> </section>
+<section id="GUID-D43830D1-D78F-48A7-8467-4E8A52FE403B"><title>Key Classes</title> <p>The classes used for SD cards are SD
+specific versions of the classes used for the MMC cards and the main SD-related
+are listed here. </p> <table id="GUID-42E860FB-DF1F-5F11-93EA-DAF25C892B9D">
+<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
+<thead>
+<row>
+<entry>Class</entry>
+<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+<entry><p> <xref href="GUID-3DC34D4F-E693-3BF0-B5D6-DF22FCE37340.dita"><apiname>DSDStack</apiname></xref>  </p> </entry>
+<entry><p>The SD protocol stack, derived from <xref href="GUID-B5193656-9819-3E00-A335-EEF1726115A5.dita"><apiname>DMMCStack</apiname></xref>.
+Uses the star topography to identify each SD card rather than the bus topography
+used by MMC. Also handles individual card initialization. </p> </entry>
+</row>
+<row>
+<entry><p> <xref href="GUID-B170A819-C146-3DD2-85C2-69CC121A9023.dita"><apiname>TSDCard</apiname></xref>  </p> </entry>
+<entry><p>Derived from <xref href="GUID-5B985623-6A0B-3FBB-90BD-367F25CC70E7.dita"><apiname>TMMCard</apiname></xref> but contains the erase sector
+size and any special formatting requirements for the SD card. Includes information
+from the SD Card Configuration Register (SCR). </p> </entry>
+</row>
+</tbody>
+</tgroup>
+</table> </section>
+<section id="GUID-BFBB02C3-1710-4F52-94C9-94386F8AEA5A"><title>Typical uses</title> <p>The typical uses for the SD card classes
+are the same as for MMC. </p> </section>
+</conbody><related-links>
+<link href="GUID-79B2CF91-FB95-5E7C-81CC-235A6A660D88.dita"><linktext>MMC Controller</linktext>
+</link>
+<link href="GUID-058BAEDF-5E04-5BB4-928F-0E0528FD9465.dita"><linktext>MultiMediaCard
+Technology</linktext></link>
+<link href="GUID-BE6AFD38-5952-537F-848C-C76C8F5FA9BF.dita"><linktext>MMC Controller
+Architecture</linktext></link>
+<link href="GUID-C059F39F-BC53-5C92-B05E-863B8CF22859.dita"><linktext>Command Objects</linktext>
+</link>
+</related-links></concept>
\ No newline at end of file