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2.2SignalDescriptions
2.3ProtocolDescriptions
2.3.1MMC/SDModeWriteSequence
PeripheralArchitecture
Table1showstheMMC/SDcontrollerpinsthateachmodeuses.TheMMC/SDprotocolusestheclock,
command(two-waycommunicationbetweentheMMCcontrollerandmemorycard),anddata(DAT0for
MMCcard,DAT0-3forSDcard)pins.
Table1.MMC/SDControllerPinsUsedinEachMode
Function
MMCandSD(1-bitmode)SD(4-bitmode)
PinType
(1)
CommunicationsCommunications
CLKOClocklineClockline
CMDI/OCommandlineCommandline
DAT0I/ODataline0Dataline0
DAT1I/O(Notused)Dataline1
DAT2I/O(Notused)Dataline2
DAT3I/O(Notused)Dataline3
(1)
I=inputtotheMMCcontroller;O=outputfromtheMMCcontroller.
TheMMC/SDcontrollerfollowstheMMC/SDprotocolforcompletinganykindoftransactionwiththe
multimediacardandsecuredigitalcards.Formoredetailedinformation,refertothesupportedMMCand
SDspecificationsinSection1.5.
Figure5andTable2showthesignalactivitywhentheMMC/SDcontrollerisintheMMC/SDmodeandis
writingdatatoamemorycard.ThesameblocklengthmustbedefinedintheMMC/SDcontrollerandin
thememorycardbeforeinitiatingadatawrite.Inasuccessfulwriteprotocolsequence,thefollowingsteps
occur:
•TheMMC/SDcontrollerrequeststheCSDcontent.
•ThecardreceivesthecommandandsendsthecontentoftheCSDregisterasitsresponse.
•Ifthedesiredblocklength,WRITE_BL_LENvalue,isdifferentfromthedefaultvaluedeterminedfrom
theresponse,theMMC/SDcontrollersendstheblocklengthcommand.
•Thecardreceivesthecommandandsendsresponsestothecommand.
•TheMMC/SDcontrollerrequeststhecardtochangestatesfromstandbytotransfer.
•Thecardreceivesthecommandandsendsresponsestothecommand.
•TheMMC/SDcontrollersendsawritecommandtothecard.
•Thecardreceivesthecommandandsendsresponsestothecommand.
•TheMMC/SDcontrollersendsablockofdatatothecard.
•ThecardsendstheCRCstatustotheMMC/SDcontroller.
•ThecardsendsalowBUSYbituntilallofthedatahasbeenprogrammedintotheflashmemoryinside
thecard.
SPRUE30B–September2006MultimediaCard(MMC)/SecureDigital(SD)CardController13
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