1 <?xml version="1.0" encoding="utf-8"?>

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     4 "Eclipse Public License v1.0" which accompanies this distribution, 

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     7     Nokia Corporation - initial contribution.

     8 Contributors: 

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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-058BAEDF-5E04-5BB4-928F-0E0528FD9465" xml:lang="en"><title>MultiMediaCard

    13 Technology</title><shortdesc>MultiMediaCard (MMC) is a low cost data storage and communication

    14 media, and is defined by the <i>MultiMediaCard System Specification</i></shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    15 <p> The MMC specification is published by the <xref href="http://www.mmca.org" scope="external">MultiMediaCard Association</xref>. </p>

    16 <p>Communication is based on a 7-pin serial bus designed to operate in a low

    17 voltage range (2.0 - 3.6V). The MultiMediaCard specification defines a communication

    18 protocol referred to as MMC mode (0-20MHz). In addition, for compatibility

    19 with existing controllers, MultiMediaCards may offer an alternative communication

    20 protocol which is based on the SPI standard (0-5MHz). </p>

    21 <section id="GUID-69DA6510-AF66-566A-9B19-5554B4743D0B"><title> Omissions</title> <p>The

    22 following features of the MultiMediaCard System Specification are not provided

    23 in the Symbian platform MultiMediaCard controller: </p> <ul>

    24 <li id="GUID-75439A4B-28C8-58A6-81A8-92BF08F490A1"><p>Stream read and write

    25 operations are not supported. </p> </li>

    26 <li id="GUID-85C665FB-152C-5A94-A245-E99D44F384C2"><p>SPI bus mode is not

    27 supported. </p> </li>

    28 <li id="GUID-26F8D809-57EF-5CCB-99A5-BFDCA59A5F76"><p>The MultiMediaCard System

    29 Specification includes a feature where a MultiMediaCard can be put into a

    30 disconnected state. This can be performed on a card which is currently in

    31 the programming state, i.e. writing data to the disk. To place that card into

    32 the disconnected state involves placing another card into the transfer state,

    33 which means giving the other card the current data transfer focus. A disconnected

    34 card will not terminate the programming operation and, if re-selected, moves

    35 back to the programming state. The Symbian platform MultiMediaCard controller

    36 does not support this mode of operation even if the underlying hardware interface

    37 does. </p> </li>

    38 </ul> </section>

    39 </conbody></concept>