sata电源及信号接口定义.docx
《sata电源及信号接口定义.docx》由会员分享,可在线阅读,更多相关《sata电源及信号接口定义.docx(7页珍藏版)》请在冰豆网上搜索。
sata电源及信号接口定义
sata电源及信号接口定义
sata电源及信号接口定义
这些天在写esata的驱动,所以将相关资料贴上!
∙Incomputerhardware,SerialATA(SATA,isacomputerbustechnologyprimarilydesignedfortransferofdatatoandfromaharddisk.ItisthesuccessortothelegacyAdvancedTechnologyAttachmentstandard(ATA,alsoknownasIDE).ThisoldertechnologywasretroactivelyrenamedParallelATA(PATA)todistinguishitfromSerialATA.
TheSerialATA[SATA]busisdefinedovertwoseparateconnectors,oneconnectorforthedatalinesandoneforthepowerlines.ASerialATAHarddrivemayalsohaveathirdconnectorforlegacyPATApowerconnections.ThePATApowerconnectormaybeusedininsteadoftheSATApowertosupplyaconnectionwhichismoreruggedandreliablethentheSATA-1powerconnection.
connector.
[ThefollowingarticleislicensedundertheGNUFreeDocumentationLicense.ItreproducestheWikipediaarticle"SerialATA"]
SATA1.5Gb/sFirst-generationSerialATAinterfaces,alsoknownasSATA/150,runat1.5Gigahertz(GHz).SerialATAuses8B/10Bencodingatthephysicallayer.Thisencodingschemehasanefficiencyof80%,resultinginanactualdatatransferrateof1.2Gigabitspersecond(Gb/s),or150megabytespersecond(MB/s).TherelativesimplicityofaseriallinkandtheuseofLVDSallowboththeuseoflongerdrivecablesandaneasiertransitionpathtohigherspeeds.
SATA3.0Gb/sSoonafterSATA'sintroduction,enhancementsweremadetothestandard.A3Gb/ssignallingratewasaddedtothePHYlayer,offeringuptotwicethedatathroughput.ToensureseamlessbackwardcompatibilitybetweenolderSATAandthenewerfasterSATA/3Gbsdevices,thelatterdevicesarerequiredtosupporttheoriginal1.5Gb/srate.Inpractice,someolderSATAsystemsthatdonotsupportSATAspeednegotiationrequiretheperipheraldrive'sspeedbemanuallyhardlimitedto150ÂMB/swiththeuseofajumperfora300ÂMB/sdrive.
LikeSATA1.5Gb/s,SATA3Gb/suses8B/10Bencodingresultinginanactualdatatransferrateof2.4Gb/s,or300MB/s.
The3.0ÂGb/sspecificationhasbeenverywidelyreferredtoas“SerialATAII”(“SATAII”),contrarytothewishesoftheSerialATAstandardsorganizationthatauthoredit.TheofficialwebsitenotesthatSATAIIwasinfactthatorganization'snameatthetime,theSATA3Gb/sspecificationbeingonlyoneofmanythattheformerSATAIIdefined,andsuggeststhat“SATA3Gb/s”beusedinstead.(TheSerialATAstandardsorganizationhassincechangednames,andisnow“TheSerialATAInternationalOrganization”,abbreviatedSATA-IO.)
SATA-IOplanstofurtherincreasethemaximumthroughputofSerialATAto600ÂMB/saroundtheyear2007.
SATA3Gb/sissometimesalsoreferredtoasSATA/300orSATAII,continuingthelineofPATA/100,PATA/133andSATA/150.
SATA6.0Gb/sSATA-IOplanstomakea6.0Gb/sstandard.Althoughthetheoreticalthoroughputwouldbedoubled,conventionalharddiskscan'tapproachsaturatingthisspeed.
SerialATAinnovationsSATAdropsthemaster/slavesharedbusofPATA,givingeachdeviceadedicatedcableanddedicatedbandwidth.WhilethisrequirestwicethenumberofhostcontrollerstosupportthesamenumberofSATAdevices,atthetimeofSATA'sintroductionthiswasnolongerasignificantdrawback.AnothercontrollercouldbeaddedintoacontrollerASICatlittlecostbeyondtheadditionoftheextrasevensignallinesandprintedcircuitboard(PCB)spaceforthecableheader.
FeaturesallowedforbySATAbutnotbyPATAincludehot-swappingandnativecommandqueueing.
ToeasetheirtransitiontoSATA,manymanufacturershaveproduceddriveswhichusecontrollerslargelyidenticaltothoseontheirPATAdrivesandincludeabridgechiponthelogicboard.BridgeddriveshaveaSATAconnector,mayincludeeitherorbothkindsofpowerconnectors,andgenerallyperformidenticallytonativedrives.Theymay,however,lacksupportforsomeSATA-specificfeatures.Asof2004,allmajorharddrivemanufacturersproduceeitherbridgedornativeSATAdrives.
SATAdrivesmaybepluggedintoSerialAttachedSCSI(SAS)controllersandcommunicateonthesamephysicalcableasnativeSASdisks.SASdisks,however,maynotbepluggedintoaSATAcontroller.
CablesandConnectorsPhysically,theSATApoweranddatacablesarethemostnoticeablechangefromParallelATA.TheSATAstandarddefinesadatacableusingsevenconductorsand8Âmmwidewaferconnectorsoneachend.SATAcablescanbeupto1m(39in)long.PATAribboncables,incomparison,carryeither40-or80-conductorwiresandarelimitedto46cm(18in)inlength.ThereductioninconductorsmakesSATAconnectorsandcablesmuchnarrowerthanthoseofPATA,thusmakingthemmoreconvenienttoroutewithintightspacesandreducingobstructionstoaircooling.UnlikeearlyPATAconnectors,SATAconnectorsarekeyed—itisnotpossibletoinstallcableconnectorsupsidedownwithoutconsiderableforce.
TheSATAstandardalsospecifiesapowerconnectorsharplydifferingfromthefour-pinMolexconnectorusedbyPATAdrivesandmanyothercomputercomponents.Likethedatacable,itiswafer-based,butitswider15-pinshapeshouldpreventconfusionbetweenthetwo.Theseeminglylargenumberofpinsareusedtosupplythreedifferentvoltagesifnecessary—3.3ÂV,5ÂV,and12ÂV.Eachvoltageissuppliedbythreepinsgangedtogether(and5pinsforground).Thisisbecausethesmallpinscannotsupplysufficientcurrentforsomedevices,sotheyarecombined.Onepinfromeachofthethreevoltagesisalsousedforhotplugging.Thesamephysicalconnectionsareusedon3.5-in(90mm)and2.5-in(70mm)(notebook)harddisks.SomeSATAdrivesincludeinPATAstylefour-pinMolexconnectorforusewithpowersuppliesthatlacktheSATApowerconnector.Also,adaptorsareavailabletoconvertaPATAstylepowerconnectortoSATApowerconnector.
ExternalSATAeSATAwasstandardizedinmid-2004,withspecificallydefinedcables,connectors,andsignalrequirementsforexternalSATAdrives.eSATAischaracterizedby:
FullSATAspeedforexternaldisks(115MB/shavebeenmeasuredwithexternalRAIDenclosures)
∙NoprotocolconversionfromIDE/SATAtoUSB/Firewire,alldiskfeaturesareavailabletothehost
∙Cablelengthisrestrictedto2m,USBandFirewirespanlongerdistances.
∙Minimumandmaximumtransmitvoltagedecreasedto400mV-500mV
∙Minimumandmaximumreceivevoltagedecreasedto240mV-500mV
USBandFirewirerequireconversionofallcommunicationwiththeexternaldisk,soexternalUSB/FirewireenclosuresincludeanIDEorSATAbridgechipthattranslatesfromtheATAprotocoltoUSBorFirewire.DrivefeatureslikeS.M.A.R.T.cannotbeexploitedthatwayandtheachiveabletransferspeedwithUSB/Firewireisonlyabouthalfoftheentirebusdatarateofabout50MB/s.ThislimitedeffectivedatatransferratebecomesveryvisiblewhenusinganexternalRAIDarrayandalsowithfastsinglediskswhichmayyieldwellover70MB/sduringrealuse.
Currently,mostPCmotherboardsdonothaveaneSATAconnector.eSATAmaybeenabledthroughtheadditionofaneSATAhostbusadapter(HBA)orbracketconnectorfordesktopsystemsorwithaCardbusorExpressCardfornotebooks.
Note:
PriortothefinalspecificationforeSATA,therewereanumberofproductsdesignedforexternalconnectionsofSATAdrives.SomeoftheseusetheinternalSATAconnectororevenconnectorsdesignedforotherinterfacespecifications,suchasIEEE1394.TheseproductsarenoteSATAcompliant.
eSATAdoesnotprovidepower,whichmeansthatexternal2.5"diskswhichwouldotherwisebepoweredovertheUSBorFirewirecableneedaseparatepowercablewhenconnectedovereSATA.
eSATAcomparedtootherbuses
eSATA
PATA
FireWire1394b
USB2.0
ActualSpeed
2.4>Gib/s
1064Mib/s
786Mib/s
~375Mib/s
Max.cablelength
2meters
46centimetres
4.5meters16cablescanbe
daisychainedupto72meters
5meters
Powercablerequired?
Yes
Yes
No
No
DevicesperChannel
1(5withmultiplier)
3(3rddevicereadonly)
63
127
BackwardcompatibilityThebackwardcompatibilityofSATAharddiscsisvirtuallynon-existentinthesensethatSATAdriveswillnotworkwiththesameconnectorsthatIDE,SCSI,oranyotherformatofharddriveconnectto.Itis,however,possibletopurchaseconvertorsthatattachtotherearoftheSATAharddiscandwillallowittofunctionasanIDEdrive.ThiscanproveusefulinsituationswhereonewishestousetheirSATAdriveonoldermotherboardsthatmaynothaveSATAconnections,etc.
SATAvsSCSISCSIcurrentlyofferstransferrateshigherthanSATA,butisamorecomplexbususuallyresultinginhighercoststotheuser.SomedrivemanufacturersofferlongerwarrantiesforSCSIdevices,however,indicatingapossiblyhighermanufacturingqualitycontrolofSCSIdevicescomparedtoPATA/SATAdevices.
conn_sata.gif(10.79KB)
3030299030-SATA-15P-RA-core-power-connector-dwg.gif(14.14KB)
类别:
电脑技术|
|添加到搜藏|分享到i贴吧|浏览(1386)|评论(0)