SD 协议中文版

1、一概述SD总线模式下CLK:时钟信号CMD:双向命令和响应信号DAT0-3:双向数据信号VDD,VSS:电源和地信号SD模式下允许有一个主机,多个从机（即多个卡）,主机可以给从机分别地址.主机发命令有些命令是发送给指定的从机,有些命令可以以广播形式发送.SD模式下可以选择总线宽度，即选用几根DAT信号线，可以在主机初始化后设置.SD总线协议SD模式下的命令和数据流都有一个开始位和结束位.命令:是在CMD上传输的用于启动一个操作的比特流.由主机发往从机，可以是点对点也可以是广播的.响应：是在CMD上传输的用于之前命令回答的比特流.由从机发往主机.数据:是在DAT上传输的比特流，双向传输.pera

2、lior!_trlresponse)o|jeratori(noda.taKDATfromri1dKrd闾CMD-commandcommandresponse无响应模式无数据模式多块读操作模式bIddcornniaridDATdalafrom-hoal1ocardsi-spai-arH-ferCMD_-1commandresponseresponseblockwrjte.operatio.nmultipleblockwriteoperatioii1DD3Iddatablockcommand-datablockcrc多块写操作模式transmrtl&rd1:-hosimFerribil:1Comm

3、sndconlenl:cDrnmandardTd归lededoy7brtCR2checksumstartbil:鈕邨301CONTENTCRC1totallength=4Bbits命令格式R1,R3bR6tansmillerbil:O=cardreaponaefes&Disecoment:mirroredcommandarrislaljsinfo卜mslion(R1responae.OCRregister(R3responaej-orR2AR6,prolecledbya7bi1CRCchecksumsianbh:afway-sJ0CONTE

4、NT1totallength48bitsk00CONTENT=CIDorCSDCRC1totall&ngth=116bits响应格式USNEtartbitaways0bil:sfwayaO-LSE(0)DATSDAT1DATOendbn：Sim仙rdbusonlyDATOused!-:VAdabua(allfourdslalinesused:D*A.T90CRC1blocklength042rS53CRC104OS42CRC1043S31CRC104M20CRC1blocklength)/数据格式SD卡上电后会自动初始化,通过给卡发送CMD0也可以复位卡.二SD卡命令描述广播命令:给所有卡都发

5、送,某些命令需要响应2点对点命令给指定地址的卡发送,需要响应SD卡系统有两种工作模式:1卡识别模式主机上电复位后即处于此模式,它会在总线上等待卡卡复位后也处于此模式,直到SEND_RCA(CMD3)命令到来.2数据传输模式卡收到SEND_RCA(CMD3)命令后即进入此模式.主机识别到卡后也进入此模式.CardstateOperationmodeinactiveStateinactiveIdleStatec:mclidentificationmcxieReartyStateIdentricationStateStand-byStatedatatransfermcxieTransferState

6、Sending-dataStateR日匚eiveCMD7-厂Transfer*State(tran)CMD17.lS.3C.56(r)ACMD51CMDl.25.26.27;42.56(w)CMD12;OperationCOEplB怕operationccimpletsCMD28.29.3BCMD13:CMD55CMD3CMDJ5cardidentificationtmodeCMD7CMD7CMDD数据传输模式下卡的状态转变图进入数据传输模式后，主机先不停的发送SEND_CSD(CMD9)命令获取卡的CSD信息.SET_DSR(CMD4)用于设置卡的DSR寄存器，包括数据总线宽度，总线上卡的数

7、目，总线频率,当设置成功后，卡的工作频率也随之改变.此步操作是可选的.CMD7命令用于使指定地址的卡进入传输模式，任何指定时刻只能有一个卡处于传输模式.传输模式下所有的数据传输都是点对点的，并且所有有地址的命令都需要有响应.所有读命令都可以由CMD12命令停止，之后卡进入TransferState.读命令包括单块读(CMD17),多块读(CMD18),发送写保护(CMD30),发送scr(ACMD51)和读模式一般命令(CMD56).所有写命令都可以由CMD12命令停止写命令包括单块读(CMD24),多块读(CMD25),写CID(CMD26),写CSD(CMD27),锁和解锁命令(CMD42

8、)和写模式一般命令(CMD56).当写命令传输完成后，卡进入ProgrammingState(传输成功)或TransferState(传输失败).如果一个卡写操作被停止，但其前面数据的CRC和块长度正确，数据还是会被写入.卡要提供写缓冲,如果写缓冲已满并且卡处于ProgrammingState,DAT0保持低BUSY.写CID,CSD,写保护,擦除命令没有缓冲,当这些命令没完时,不应发送其他的数据传输命令.参数设置命令在卡被编程时是不允许发送的，这些命令包括设置块长度(CMD16),擦除块起始(CMD32)和擦除块结束(CMD33).当卡正编程时读命令是禁止的.用CMD7使另一个卡进入Tran

9、sferState不会终止当前卡的编程和擦除，当前卡会进入DisconnectState并且释放DAT线.DisconnectState模式的卡可通过CMD7重新被选中,此时卡进入ProgrammingState并且使能busy信号.CMD0或CMD15会终止卡的编程操作,造成数据混乱,此操作应禁止.总线宽度选择命令ACMD6命令用于选择总线宽度，此命令只有在TransferState有效.应在CMD7命令后使用.块读命令块是数据传输的最小单位，在CSD(READ_BL_LEN)中定义，SD卡为固定的512B.每个块传输的后面都跟着一个CRC校验.CMD17(READ_SINGLE_BL0CK

10、)用于传输单个块，传输完之后,卡进入TransferState.CMD18(READ_MULTIPLE_BLOCK)用于多个块的传输，直到收到一个CMD12命令.块写命令与块读命令类似，每个块传输的后面都跟着一个CRC校验.卡写数据时会进行CRC校验.多块写比重复的单块写更能提高效率.如果CSD中的WRITE_BLK_MISALIGN没设置，并且发送的数据不是块对齐的，卡会设置状态寄存器中的ADDRESS_ERROR位，并且进入Receive-data-State状态等待停止命令此时写操作也会停止，并且卡会设置其的WP_VIOLATION位.如果写缓冲满的话，卡会停止接受WRITE_BLOCK

11、命令.此时主机应发送SEND_STATUS(CMD13)命令，卡返回数据的READY_FOR_DATA位标志卡是否准备好接受新的数据.在多块写操作中通过事先发送ACMD23命令可提高写速度.ACMD23用于定义接下来要写数据的块的数目.每次多块写操作后，这个值又被设为默认的1.ACMD22会使卡返回写成功的块数目.擦除命令擦除命令的顺序是:ERASE_WR_BLK_START(CMD32)，ERASE_WR_BLK_END(CMD33)andERASE(CMD38).如果(CMD38或(CMD32,33)接收到出错信息，卡会设置状态寄存器中的ERASE_SEQ_ERROR位并且重新等待新的命令

12、时序.如果接收到时序错误命令，卡会设置其ERASE_RESET位并且重新等待新的命令时序.写保护管理三种机制:-.写保护物理开关-.卡内部写保护通过设置CSD中的WP_GRP_ENABLE位和WP_GRP_SIZE位，SET_WRITE_PROT和CLR_WRITE_PROT命令用来设置和清除保护机制.-.密码保护.三.时钟控制如果主机要发送1K的数据，但是主机缓冲区只有512B,那么主机可以在发送完前512B后,可以先停止时钟,然后把后512B填充入缓冲区,再启动时钟,这样卡并不会检测要两次发送之间的间隔,认为其是一次完整的数据发送过程.四CRC校验CRC7CRC7用于所有的命令，除R3以外

13、的响应，以及CID和CSD寄存器.CRC16CRC16用于数据块的校验五.错误类型.1.CRC错误和命令非法错误命令的CRC校验出错，卡设置其状态寄存器的COM_CRC_ERROR位.非法命令错误,卡设置其状态寄存器的ILLEGAL_COMMAND位.非法命令包括:不支持的命令，未定义的命令以及当前状态不支持的命令.2.读，写和擦除超时.卡应该在指定的时间内完成一个命令或返回移动的错误信息.如果在指定的超时时间内主机收不到响应，应认为卡停止工作，应重新复位卡.六命令1.命令类型:-bc不需要响应的广播命令.-bcr需要响应的广播命令.每个卡都会独立的接收命令和发送响应.-ac点对点命令,DAT

14、线上没数据-adtc点对点命令,DAT线上有数据所有命令均遵守上图中的格式,总共48位.首先是1个起始位0,接着是1个方向位（主机发送位1）,6个命令位（0-63）,32位参数（有些命令需要），CRC7位校验，1个停止位.2.卡命令根据不同的类型分成了不同的Class,见下表，其中Class0,2,4,5,8是每个卡都必须支持的命令，不同的卡所支持的命令保存在CSD中.CardCommandClass(CCC)012345、B789-11Supportedcommandsclassdescriptionbasicreservedblockreadreservedblxkwriteerasewr

15、iteprotectionlockcardapplicationspecificreservedCMDOFvlandatOry卡CMD2fvlandatory+CMD3FvlandatOry卡CMD4Fvlaridatory+CMD7Fvlandatory+CMD9Fvlaridatory+qCMD1DFvlandatory+CMD12Fvlaridatory+CMD13Fylarid自tory+CMD15rvlandatory+CMD16Pslarid自tory+CMD17rvlandatory+CMDIfiPslarid自tory+CMD24rvlandatory+CMD25Pslarid

16、自tory+CMD27MsndatDry+CMD2SOptional+CMD29Optional+CMD30Optional+CardCommandClass(CCC012345s789-11SupportedcommandsclassdescriptionbasicreservedblockreadreservedblockwriteerasewriteprotectionlockcardapplicationspeciicresrvedCMD32即自rd自tdry+CMD33M自怕自tDry+CMD3aMandatory+CMD42Optional+CMD55即自rd自tdry+CMD56

17、M自怕自tDry+ACMD6Mandatory+ACMD13Msndstory+ACMD22即自rd自tdry+ACMD23M自怕自tDry+qACMD41Mandatory+.ACMD42Fvlandstory+ACMD51M自rd自tdry4-命令详细描述1）基本命令Class0CMDINDEXtypeargumentrespabbreviationcommanddescriptionCMDObe31:QJsti/fbits-GODLESTATEresetsallcardstoidlestateCMD1reservedCMD2bcr31:0stuffbitsR2ALL_SEND_CIIDa

18、sksanycardtosendtheCIDnumbersantheCMDline(any匚mrdthatisconnectedtothehostv/illrespondCMD3bcr31:0stuffbitsR6SEND_RELATIVE_addraskthecardtopublisha.newrelativeaddressRCA)CMD4be31:16DSR15:0stuffbitsSET_DSRprogramstheDSRofallcardsCMD5reservedCMD6reservedCMDINDEXtypeargumentrespabbreviationcommanddescrip

19、tionCMD7ac31:16RCA15:0stuffbitsR1b(onlyfemInaselectedSELECT/DESELECT_CARD-commandtogglesacardbetweenthestand-byandtransferstatesorbetweentheprogramminganddisconnectstates.Inbothcasesthecardisselectedbyitsownrelativeaddressandgetsdeselectedbyanyotheraddress:address0deselectsall.CMD3reservedCMD9ac31:1

20、6RCA15:0stuffbitsR2SEND_CSDaddressedcardsendsitscard-5pacificdata(CSDontheCMDline.CMD10ac31:16RCA15:0stuffbitsR2SEND_CIDaddressedcardsendsitscardidentification(CIDonCMDtheline.CMD11reservedCMD12ac31:0stuffbitsRibSTOP_TRANSMISSIONforcesthecardtostoptransmissionCMD13ac31:16RCA15:0stuffbitsR1SEND_STATU

21、Saddressedcardsendsitsstatusregister.CMD14reservedCMD15ac31:16RCA15:0stuffbitsGOINACTIVESTATEsetsthecardtoina匚tiw已stateinordertoprotectthe匚日dstm匚kagainstcam-mLinicationbreakdowns.读命令Class2CMDINDEXtypeargumentrespabbreviationcommanddescriptionCMD16ac31:0blocklengthR1SETBLOCKLENsetstheblocklength(inby

22、tes)forallfollowingblockcommands(readandwrite)DefaultblocklengthisspecifiedtntheOSD.SupportedonlyifPartialblockRD/WRoperationareallowedinCSD.CMD17adtc31:0dataaddress快READ_SINGLE_BLOCK-readsablockofthesizeselectedbytheSETBLOCKLENcommand.1CMD18adtc31:0dataaddressR1READ-MULTIPILEBLOCK-continuouslytrans

23、fersdatablocksfromcardtohostuntilinterruptedbyaSTOPTRANSMISSIONcommand.CMD19reservedCMD23写命令Class4CMDINDEXtypeargumentrespabbreviationcommanddescriptionCMD24adtc31:0dataaddressR1WRITERLOCKwritesa.blackofthesizeselectedbytheSETBLOCKLENcommandCMD25adtc31:0dataaddressR1WRITEMULTIPLEBLOCKcontinuauslywri

24、tesblocksofdatauntila.STOPTRANSMISSIONfollows.CMD26ReservedFarManufacturerCMD27adtc31:0stuffbitsR1PROGRAM_CSDprogrammingoftheprogrammablebitsoftheCSD.3）擦除命令Class5CMDINDEXtypeargumentreapabbreviationcommanddescriptionCMD32ac31:0dataaddressR1ERASEWR_BLK_START-setstheaddressofthenrstwriteblocktobeerase

25、d.CMD33ac31:0dataaddressR1ERASE_WRBLKENDsetstheaddressofthelastwriteblockofthecontinnousrangetobeerased.CMD34reservedCMD374）应用特定命令Class8CMDINDEXtypeargumentreapabbreviationcommanddescriptionCMD55ac31:16RCA15:0stuffbitsR1APPCMDIndicatestothecardthatthenextcommandisanapplicationspecificcommandratherth

26、ana.standardcommandCMD56adtc31:1stuffbits.Q:RD/WR1尸cUsedeithertotransferadatablocktothe匚日dortogeta.datablockfromthecardfargeneralpurpose/applicationspecriccommands.ThesizeofthedatablockshallbesetbytheSET_BLOCKLENcommand.CMD57reservedCMD59CMD60-63reservedformanufaatLirerF表中的所有命令使用前都应先跟一个APPCMD(CMD55)

27、命令ACMDriDEXtypeargumentirespabbreviationcommanddescriptionACMD6ac31:2stuffbits1:0bLiswidthR1SET_BUS_WIDTHDefinesthedatabuswidth(OO=1bitor10-4bitsbustobeusedfordatatransfer.ThealloweddatabuswidthsaregiveninSCRregister.adtc31:0stuffbitsR1SD_STATUSSendtheSDMemoryCardstatus.ThestatusfieldsaregiveninTabl

28、e24.ACMD17reservedACMD1S一ReservedfarSDsecLirityapplications1ACMD19toACMD21reservedACMD22adta31:0stuffbitsR1SEND_NUM_WR_BLOCKS-Sendthenumberofthewritten(withouterrorswriteblacks.Respondswith32bitTcRGdatablock.ACMD23ac31:23stuffbits22:0NumberofblocksR1SET_WR_BLK_ERASE_COUNTSetthenumberofwriteblockstob

29、epre-erasedbeforewriting(tobeusedforfasterMultipleBieckWRcommand.1-default(onewrblack-21.ACMD24reservedACMD25ReservedforSDsecurityapplications1ACMD26一ReservedforSDsecurityapplications1ACMD33一ReservedforSDsecurityapplications1ACMD39toACMD40reservedACMD41bar31:0OCRwithoutbusyR3SDAFPOPCOND三三Askstheacce

30、ssedcardtosenditsoperatingcanditionregister(OCR)contentintheresponseantheCMDline.ACMD42ac31:1stLif*bits0set_cdR1SETCLRCARDDETECTJCanneat1)/Disconrect0theSOKOHwnpull-LipresistoronCD/DAT3(pin1ofthecard.Thepull-upmaybeusedforcarddetection.ACMD43ACMD49一一ReservedforSDsecurityapplications1ACMD61adtc31:0st

31、affbitsR1SEMD_SCRReadstheSDConfigurationRegister(SCR).卡状态转换表currentstateidlereadyidentstbyIrandatarevprgdisinacommandchangestoclassindependentCRCerror匚cmmandnotsupportedcla0CMDOidleidleidleidleidleidleidleidleidleCMD2ident-CMD3&tbystbyCMD4stbyCMID7,cardisaddressedtran片-pprgCMD7?cardisnotaddressedsib

32、ystbystbydisCMD9stbyCMD10stbyCMD12-tranpgCMD13stbytrandatarevprgdisCMD15inainainainainainacla&B2CMD16-tran_CMD17-dataCMD18-Uatacla&s4J|FCMD16seedass2CMD24-rev-CMD25*-rev-CMD27-rev-cla&6CMD28-prg-CMD29-pg-CMD30-data-cla&B5currentstateidlereadyidertstbytrandatarevprgdisinaCMD32-tran-CMD33-tran-CMD3B-p

33、rg-cla&s7CMD42-rev-cla&s8CMD55idlestbytrandatarevprgdisCMD56;RD/WR=0-revCMD56;RD/WR=1-dataACMD6-tranACMD13-tranACMD22-tran,ACMD23-tranACMDia725.26.3Sr.47,48.49Referto”SDMemoryCardSecuritySpecificationforexplanationabouttheSDSecurityFeaturesACMD41.cardVDDrangecompatibleready-ACMD41.cardisbu

34、syidle-ACMD41.cardVDDrangenotcompatibleina-ACMD42-tran-ACMDS1-data-class9-11CMD41:CMD斗3CIVI口54.CMD57-CMD59reservedCMD60.CMD63reservedformanufacturer应答所有的应答都是通过CMD发送，不同的应答长度可能不同总共有四种类型的应答.1.R1：长度位48位注意每个块传输完成后有一个BUSY位.2.Rlb:与R1类似，只是将BUSY位加入响应中.3.R2（CIDCSD寄存器）：长度为136位，CID为CMD2和CMD10的应答，CSD为CMD9的应答.Bit

35、position135134fl133:12S0Width(bits)1161271Value*0111111XTDescriptionstartbittransmissiDnbitreservedC1DarCSDernalCRC7endbit4.R3（0CR寄存器）：长度位48位.作为ACMD41的应答.5.R6（RCA地址应答）：长度为48位Bitposition474G45:40J39:BArgumentfield7：1QjWidth(bits116161GJF71ValueOOXXXXJDescriptionstartbittransmissionbit

36、commandindexf000011iNewpublishedRCA31:16tfthecard115:0cardstatusbits:23,22,19,12:0(seeTable22CRC7endbit卡的状态SD卡支持两种状态:-卡状态:与MMC卡兼容.-SD卡状态:扩充到了512位.1.卡状态:R1应答包含一个32位的卡状态.见下表.其中Type中的含义为:E:错误位.S:状态位.R:根据命令在响应中设置.X:根据在命令执行期间设置,必须再次读此位才能获得命令执行后的情况.ClearCondition:A:与卡的当前状态有关B:总是与命令有关,无效的命令会清除此位.C:通过读此位来清除

37、BitsIdentifierTypeValueDescriptionClearCondition31OUTOFRANGEERO-noerror1=errorThecommandsargumentwasoutoftheallowedrangeforthiscard.C30ADDRESS_ERRORERXO-noerror1=errorAmisalignedaddresswhichdidnatmatchtheblocklengthwasserfinthecommand.C25BLOCK_LEN_ERRORERO-noerror1=errorThetransferredblocklengthisno

38、tallowedfarthiscard,orthenumberoftransferredbytesdoesnotmatchtheblocklength.kc28ERASE_SEQ_ERRORERO-noerror1=errorAnerrorinthesequenceoferase匚ommandsoccurred.c27ERASE_PARAMEX=noerror1-errorAninvalidselectionofwrite-blo匚kmforeraseoccurred.c26WP_VIOLATIONERX0=notprotectedT=protectedAttempttoprogramawri

39、teprotectedblockc25CARD_lSHOCKEDSXO=cardunlockedV=cardlockedWhenset;signalsthatthecardislockedbythehostA乙LOCK_UNLOCK_FAILED_ERXO=noerrorT=errorSetwhenasequenumarpassworderrorhasbeendetectedinlock/nlo匚比匚日rdcommandoriftherewasanattempttoaccessa.lockedcardC23COM_CRC_ERRORER0=noerror1=errorTheCRCcheckof

40、thepreviouscommandfailed.B22LLEGAL_COMMANDER0=noerror1-errorCommandnotlegalforthecardstateB21CARD_ECC_FAILEDEXO-successT=failureCardinternalECOwasappliedbutfailedtoconeGtthedata.C20CC_ERRORERX0=noerror1=errorInternalcardcontrollererrorC19ERRORERXQ-noerror1=errorAgeneraloranunknownerroroccurredduring

41、theoperation.C18UNDERRUNEXO-noerror1-errorThecardcouldnotsustaindatatransferinstreamreadmodeC17OVERRUNEXO-noerror1-errorThecardcouldnotsustaindataprogramminginstreamwritemodeC16CID/CSD_OVERWRITEERXO-noerror1-errorcanbeeitheroneofthefollowingerrors:-TheCIDregisterhasbeen日Ireadywrittenandcannotbeoverw

42、ritten-ThereadonlysectionoftheCSDdoesnotmatchthecardcontent-Anattempttoreversethecopy(setasoriginal)orpermanentWP(unprotected)bitswasmade.C15WP_ERASE_SKIPSX0=notprotected1-protectedOnlypartialaddressspacewaserasedduetoexistingwriteprotectedblocks.”C14CARD_ECC_DISABLESX0=enabled1-disabledThecommandha

43、sbeenexecutedwithoutusingtheinternalECC.A13ERASERESETSR=cleared11-setAnerasesequencewasclearedbeforeexecutingbecauseanoutoferasesequencecommandwasreceivedC12:9SX0=idle=ready=ident=stby=tran-data=rev7=prg3-dis9-15=reservedThestateofthecardwhenreceivingthecommand：fthecommandexecutioncausesastatechange

44、,itwillbevisibletothehostintheresponsetothenextcommand.Thefourbitsareinterpretedasabinarycodednumberbetween0and15.B8READY_FOR_DATASX0=notready1-readycorrespondstobufferemptysignallingonthebusA7:65APP_CMDSRO=Disabled1=EnabledThecardwillexpertACMD.orindicationthatthecommandhasbeeninterpretedasACMDC4re

45、served3AKE_SEQ_ERROR(SDMemoryCardapp.spec.)ERO=noerrorT=errorErrorinthesequenceofauthenti-catianprocessC表指明了哪些命令可能使哪些位产生变化CMD#ResponseFormat1Statusbit#3130292827262524232221201913171615141312:9853XXXX7XXXXXXXXXXXXXXXX12XXXXXXXXXXXXX13XXXXXXXXXXXXXXXXXX16XXXXXXXXXXXXXXXXX17XXXXXXXXXXXXXXXXXX18XXXXXXX

46、XXXXXXXXXXX24XXXXXXXXXXXXXXXXXXX25XXXXXXXXXXxXXXXXXXX2&XXXXXXXXXXXXXXXX27XXXXXXXXXXX盂XXXX28XXXXXXXXXXXXXXXX29XXXXXXXXXXX4KXjXXXX30XXXX*XXXXXXXXXXXX32XXXXXXXXXXXXXXXXXX33XXXXXXXXXXXXXXXXX38XXXXXXXXXXXXXXXXX42XXXXXXXX.XXXXXXX55X1XXXXXxkXXXXXXXX55XXXXXXXXXXXXXXXXXXACMDBXXXXXXXXXXXXXXXXXACMD13XXXXXX：XXX

47、XXXXXXXXACMD22XXXXXXXXXXXXXXXXXACMD23XXXXXXXXXXXXXXXXXACMD42XXXXxXXXXXXXXXXXXACMD51XXkXXXXXXXXXXXXXX2.SD卡状态:这些位通过DAT线传输，并伴有CRC16校验.其是作为ACMD13的应答.BitsIdentifierTypeValueDescriptionClearCondition511:510DAT_BUS_WIDTHSR00-1(default)01=reserved10=4bitwidth1T=reservedShowsthecurrentlydefineddatabuswidthth

48、atwasdefinedbySET_0US_WIDTH匚ommandA509SECURED_MODESRO-Notinthemode1-nSecuredMadeCardisinSecuredMcxieofoperation(refertoSDSecurity宕pm匚鬥匚吕-tion).A508:496reserved495:480SD_CARD_TYPESRAll0=SDMemoryCards(asdefinedinPhysicalSpecVer.1E日匚bitwilldefinedifferentSDTypeVariaidsSDTypestobedefinedinthefutureA479:

49、448SIZE_OF_PROTECTEDAREASRSizeofprotectedarea(inunitsofMULrBLOCK_LENrefertoCSDregisterTable5.3)Showsthesizeofprotectedarea.Theactualarea=(SIZE_OFROTECTEDAREA)*MULT*BLOCK_LEN.-A447：312reserved311:reservedformanufacturer十.卡存储器形式.-块:块是基本读写命令的单位,它可以是固定的或可变的.关于块的大小以及其是否可变性存储在CSD中.-扇区:扇区是擦除命令的单位，它是固定的值，保存

50、在CSD中.SStartbit(=O1TTransmitterbit(F1ost=1,Card=0POne-cyclepull-up(=1)EEndbit(-1Zlighimpedan匚estate卜*=1DDatabitsXDontCaredatabits(fromcard)也RepetitionCyclicredundan匚丫匚heckbits(7bitsCardactiveHostactive时序图中字母含义:一.时序图1.命令和应答1）卡识别和卡工作电压确认模式:CMD2,ACMD41CMDHostcommand-N(dcycles亠ci-C1DorOCR出ST匚ontentCRCEZ

51、ZP、psTcontentZZZ2）地址分配模式:CMD3尺匚yclES-：-ResponseSTcontentCRCEZZP击*沖pSTcontentCRCEZZZ3）数据传输模式:SMDHostcommand-*NC7匚ycles-ResponseST匚ontentCRCEZZP44pSTcontentCRCEZ224）命令结束-下一个命令:5）两个命令直接Hostcommand5乂cycles=-Host匚ommand*STcontentCRCEZ出击击击斗出ZSTcontentCRCE2.数据读.1）单块读:CMD17CMDDATST匚omtentCRCEZzP*pSTcontentC

52、RCE一=N丸ccyclesa心ReadDataZZZ&ZzzP44厶444pSDDD*2）多块读:-ReadData”亠忖也c刃匕馆nDATZZ厂ZZZZzzp击击誉-it誉击占PScontentCRCEp击击击击击击击PSDDDDD读过程时序.CMDDATHostcommand%尺cycles亠JResponse亠STcontentCRCEZZP*pSTcontentCRCEDDD*DDDEZ7*厶*dt*dr*停止命令时序数据写1）单块写：w-N匚比-aCMDEZZppsTContentCRCEZzp、厶4、44444444444444PppppPpPJ瓯kWritedata-aCRCs

53、tatusDATODAT1-3Z2XXJb-XXi-22ZJt4JL*Z22Zp4pScontentCRCEzzSStatusEsL*LE2Z244444422Z44Z22zp4pScontentCRCEzzXXXXXXXXX2注意Busy信号.2）多块写：CMDEz2PpPPP444申*4皆444ppPppPPPP庶ACRCstatus-Writedata亠CRCstatusDATZzP亠PSDsts+CRCEzzSStatusEZP亠PSDsts+CRCEzZSStatusEsL*LEZP亠P多块写命令时序CMDNuCyclesaCardresponseasTcontentCRCEZZPS

54、TcontentCRCESTContentDATDDDDDDDDDDEZzgl_444444占4444444EZZz2ZZ2Z停止命令时序CMDNuCyclesasTcontentCRCEZZPSTcontentCRCESTContent-Databloc：k-CRCStatus1DATDDDDD2ZsStatusE2zg|_厶占、占厶占、E2ZZZZZ2Z卡主动停止时的时序时序值MinjMaxUnitncr264clockcyclesNid55clockcyclesNauJ|2TAAC+NSACclockcyclesNrC8dockcyclesNCCBg-clockcyclesnwr2-cq

55、cKcycles十二.寄存器SD卡有六个寄存器OCR,CID,CSD,RCA,DSRandSCR.其中前四个保存卡的特定信息,后两个用来对卡进行配置.1.OCR寄存器:保存有卡支持的工作电压，支持的话相应的位置1,否则为0.OCRbitpositionVDDvoltagewindow0-3reserved41.6-1.751.7-1.a61.8-1.971.9-2.0丄Aa2.0-2.119102.2-2.3112.3-2412132.5-26A14|2.6--2.8162.a-2.g183.0-3.1191-3.220U3.2-3.3213.3-3.4223.4-3.523

56、3.6-3.624-30reserved31cardpowerupstatusbit(busy12.CID:保存有卡的身份信息.NameFieldWidthClD-sliceManufacturerIDMID8127:120OEM/ApplicationIDOID16119:104ProductnamePNMi0103:64ProductrevisionPRV863:56ProductserialnumberPSN3255:24reserved-423:20ManufacturingdateMDT1219:BCF1C7checksLimCRC1【FJnotused,always1-10：0lC

57、SD保存有如何访问卡的信息.NameCSDstructurereserveddatareadaccess-time-1datareadaccesE-time-2inCLKcycles(NSACMOO)max.datatransferratecardcommandclassesmax.readdatablockpartialblacks*oreadallowedwriteblockmisalignmentreadblockmisalignmentDSRimplementedreserveddevi匚日sizemax.readCLirrentVDDminmax.readCLirrent迄Vdmaxmax.writecurrentVDDminmax.writecurrent遽甘ddniaxdevicesizemultipliererasesingleblockenableerasesectorsizewriteprotectgroupsizewriteprotectgroupenableFieldDSRIMPR2WFACTORFILEFORMATGRPERASE_BLK_ENSECTORSIZETAA