Tải bản đầy đủ - 0 (trang)
Chapter 8.  Expansion Card Buses

Chapter 8.  Expansion Card Buses

Tải bản đầy đủ - 0trang

expansioncardsforlaptopshavegrownwellbeyondtheir

simplememorycardorigins.Table8.1showsthehistoryof

PCMCIA,PCCard,andExpressCardstandardsandrevisions.

Table8.1.PCMCIA,PCCard,andExpressCardRevisions

Standard



DateReleased



MajorFeatures/Changes



PCMCIA1.0

(JEIDA4.0)



June1990



Basedon16-bitAT-bus

(ISA)68-pinmemory-only

interfaceTypeI/IIform

factorsCardInformation

Structure(CIS)defined



PCMCIA2.0

(JEIDA4.1)



September1991



PCCardnameadoptedI/O

interfaceaddedDualvoltagememorycard

supportEnvironmental

requirementsSocket

ServicesAPIspecification

EnhancedMetaformat

(geometryandinterleaving

tuplesadded)XIP(eXecute

InPlace)spec.added



PCMCIA2.01



November1992



PCCardATAspecification

TypeIIIformfactorAutoIndexingMassStorage

(AIMS)specificationCard

ServicesAPIspecification

EnhancedSocketServices

supportEnhanced

Metaformat



PCMCIA2.1

(JEIDA4.2)



July1993



CardandSocketServices

enhancedElectricaland

physicalspec.enhanced

EnhancedMetaformat



PCCard5.0



February1995



32-bitCardBusadded,

basedonPCICIS(Card

InformationStructure)

requiredLowvoltage(3.3V)

onlyoperationHardware

DMAsupportAdvanced

PowerManagement(APM)

addedMulti-functioncards



Guidelinesdocumentadded

PCCard5.01



March1995



Generaleditorialchanges



PCCard5.02



May1995



Electricalspec.editorial

changes



PCCard5.03



November1995



Supportforcustom

interfacesadded



PCCard5.04



March1996



ZoomedVideosupport

addedFlashTranslation

Layer(FTL)



PCCard6.0



March1997



Thermalratingssystem

ISDN,Security,and

InstrumentationCard

TuplesHotDock/Undock

supportStreamlined

configuration



PCCard6.1



April1998



PCIpowermanagement

SmallPCCardformfactor

Win32SocketServices

bindings



PCCard7.0



February1999



PCCardmemorypaging

DigitalVideoBroadcast

(DVB)interfaceWinNT4.0

KernelmodeSocket

Servicesbindings



PCCard7.1



March2000



OpenCablePODinterface

support



PCCard7.2



November2000



RemovalofDMAsupport

ZoomedVideoportregister

modelUpdatedPCCard

ATAspec.Limitedhost

guidelines



PCCard8.0



April2001



CardBayUSBinterface

Vcoresupplementalvoltage

added



PCCard8.1



2003



DedicatedLPC(LowPin

Count)interfaces



ExpressCard1.0



September2003



PCIExpressandUSB2.0

combinedExpressCard/34

and54formfactors



Note:Atuplegivesasetofthingsthatparticipateinarelation

betweenthosethings.Forexample,JohnandJanecanbelinkedby

themarriagerelationandclassifiedasthetuple(John,Jane).



Thefollowingsectionsdiscusstheseexpansioncardbusesin

furtherdetail.



PCCards(PCMCIA)

AlthoughtheywereoriginallycalledPCMCIACards,afterthe

secondreleaseofthespecificationin1991,thesecardsare

moreaccurately(andofficially)calledPCCardsinstead.

However,tothisdaymanypeople(includingmyself)stillcall

themPCMCIACards,eventhoughthatisnolongertechnically

correct.

ModernPCCardssupportavarietyofapplications;the

functionalitythatcanbeaddedtoasystemthroughPCCard

technologyisenormous.Virtuallyanytypeofinterfaceor

adapterthatcanbeaddedtoadesktopsystemviaISA

(IndustryStandardArchitecture)orPCI(PeripheralComponent

Interconnect)buscardscanalsobeaddedtoalaptopor

notebooksystemviaPCCards.

ThePCCardslotsfoundinlaptopandnotebooksystemsenable

youtoaddUSBports,FireWireports,serial(RS-232)ports,

parallelports,fax/modems,cellularmodems,ParallelorSerial

ATAports,SCSIadapters,wirelessorwirednetworkinterface

adapters,1.8-inchharddrives,TVtuners,soundcards,GPS

(globalpositioningsatellite)receivers,andmanyothertypesof

devicestoyoursystem.IfyourcomputerhasPCCardslotsthat

conformtothestandardsdevelopedbythePCMCIA,youcan

insertanytypeofPCCard(builttothesamestandard)into

yourmachineandexpectittoberecognizedandusable.

AlthoughtheoriginalPCCardspecificationwasonlyformemory

cards,infactthathasturnedouttobetheleastpopularuse,

andalmostnobodyusesPCMCIAmemorycardstoday(often

calledlinearmemory,todistinguishthemfrommodernflash

memorycards).Thememorycardfunctionwasdesignedata

timewhenthesystemsranmuchslower,anditwasthought

thatopeningupalaptoptoaddchip-basedmemorywouldbe

toodifficult.Theideawasthatyoucouldinsertamemorycard



intothesystem,therebyupgradingthememoryinan

extremelyeasyfashion.ComparedtoastandardSIMM(single

inlinememorymodule)orDIMM(dualinlinememorymodule),

theoriginalPCMCIAmemorycardswereveryexpensive.They

werealsomuchslower.TheoriginalPCCardbuswasbasedon

theslowISAbusandranatonly10MHz,whichwasfastenough

forsystemsbackin1990,butnotfastenoughforsystemsthat

followed.Mostlaptopmanufacturersoptedtousesmallerand

fasterSODIMMs(smalloutlineDIMMs)foraddingmemoryto

laptopsystemsinstead.TheSODIMMswerenormallyinstalled

insocketsunderacoverplate,andranatthefullspeedofthe

memorybusinthesystem.



PCCardBusTypes

PCCardsevolvedintoamethodforaddingthesamelevelof

expansiontoportablesystemsthatwasalreadyavailableon

desktopsystems.TherearetwobusstandardsforPCCards:PC

Card-16(16-bit)andCardBus(32-bit).PCCard-16runsat

10MHzanddoes16-bittransfers,foramaximumthroughputof

20MBps.Itcanbethoughtofasthemobileequivalentofthe

ancientISAbus.CardBusrunsat33MHzanddoes32-bit

transfers,foramaximumthroughputof133MBps(sameas

PCI).It'sessentiallymobilePCI.Table8.2summarizesthe

differencesbetweenPCCard-16andCardBus.

Table8.2.PCCardBusTypes

Feature



PCCard-16



CardBus



Voltage



5V/3.3V



3.3V



Design



ISA



PCI



Interrupts



Non-Shareable



Shareable



Speed



10MHz



33MHz



Datawidth



8/16-bit



32-bit



Transferrate



20MBps



133MBps



AlthoughbothPCCard-16andCardBuscardsusethesame

basic68-pinconnectors,theyareactuallyslightlydifferentin

keying,suchthataPCCard-16cardplugsintoaCardBusslot,

butaCardBuscarddoesnotplugintoanolderPCCard-16slot.

AllCardBusslotsarerequiredtosupportPCCard-16cardsas

wellasCardBuscards.Virtuallyall486processorandmost

earlyPentiumprocessorbasednotebooksincludeonlyPCCard16slots,whereasmostsystemsbasedonmid-1996andlater

PentiumorhigherprocessorsincludeCardBusslots.Ifasystem

hastwoslots,insomecasesonlyoneofthemisCardBus

capable.

IfyouareunsureaboutwhattypeofPCCardslotsyourlaptop

includes,checkthespecifications.Ifthespecificationsindicate

thattheslotssupportPCMCIA2.x,thentheysupportonlyPC

Card-16cardsbecauseCardBusisincludedinthe5.xandlater

standardsonly.Normally,thespecificationsstatethattheslots

areCardBusslotsiftheyhavethatcapability.CardBuscards

includeametalshieldwithraisedbumpsaroundthe68-pin

connector.Thebumpsarepartofthekeyingthatpreventsthem

frombeinginsertedintoolderPCCard2.xslots.

BecauseCardBuscardsarebasedonPCI,theycanshare

interruptsusingPCIbusIRQsteering,unlikeISA-basedPC

Card-16cards,whichcannotshareinterrupts.PCIbusIRQ

steeringgivestheoperatingsystemtheflexibilitytoreprogram

andsharePCIIRQswhenitrebalancesPlugandPlayresources.

WhenPCCard-16cardsareusedwithoutshareableinterrupts,

theoperatingsystemmaynotbeabletofindenoughfree



interruptsforalldevicestowork,andsomemayendupbeing

disabledbythedevicemanager.

MostnewerandfasterPCCardsusetheCardBusinterface,

whichvirtuallyallnewerlaptopssupport.Still,youshouldcheck

tobesureyourlaptopdoeshaveCardBussupportbefore

purchasingCardBuscards.Dependingonthecardyou

purchase,youshouldlookforCardBus-typecardsaswell.Cards

supportingslowerinterfaces(suchasmodems,forexample)

areusuallyavailableinPCCardversionsbecausetheydon't

haveaneedforgreaterthan20MBpsthroughput.Still,because

CardBuscardssupportPCIIRQsharing,theyhavebenefits

beyondtheirhigherthroughput.

Forexample,AdaptecmakestwoPCCardSCSIadapters,called

theAPA-1460(PCCard-16)andtheAPA-1480(CardBus).The

1460isaFast-SCSIadapter,whereasthe1480isanUltra-SCSI

adapterwithtwicethespeedofthe1460.The1460hasonly

oneadvantage,anditwillworkinanysystemwithaPCCard

slot.The1480willworkinCardBusslots,whichwouldbefound

inmostsystemsdatingfrommid-1996tothepresent.

Switchingtothefaster1480CardBusadaptercutmytape

backuptimesinhalf,anditallowsmySCSICD-ROMdriveto

workatfullspeed.Formostsituationsinwhichyouhavea

choicebetweenaPCCard-16andCardBusversionofacard,

you'rebestoffgoingwiththeCardBusversion.



PCCardPhysicalTypes

ThePCCardstandardalsodefinesthreephysicaltypesforPC

Cards,whichapplytoeitherthoseusingthePCCard-16or

CardBusinterface.Thethreephysicaldesignsareshownin

Table8.3.

Table8.3.PCCardPhysicalTypes



PCCard

Sizes



Length



Width



Thickness



Volume



TypeI



54.0mm

(2.13in)



85.6mm

(3.37in)



3.3mm

(0.13in)



15.25cc

(0.93ci)



TypeII



54.0mm

(2.13in)



85.6mm

(3.37in)



5.0mm

(0.20in)



23.11cc

(1.41ci)



TypeII



54.0mm

(2.13in)



85.6mm

(3.37in)



10.5mm

(0.41in)



48.54cc

(2.96ci)



Asyoucanseefromthetable,allthePCCardshavethesame

lengthandwidth;onlythethicknessvaries.Allthecardsare

physicallybackwardcompatible,whichmeansthatifaslotwill

fitaTypeIIIcard,thenaTypeIIorTypeIwillfitaswell.Slots

thatacceptTypeIIcardswillfitTypeIcards,butnotTypeIII

cards.Onrareoccasions,youwillseeaTypeIonlyslot,which

accommodatesonlyTypeIcards.

MostsystemsincorporatetwoPCCardslotsinastacked

arrangement.TheupperslotcanaccommodateTypeIorII

cards,whereasthebottomslotcanaccommodateTypeI,II,or

IIIcards.Unfortunately,ifaTypeIIIcardisusedinthelower

slot,itwillphysicallyencroachonthespacefortheupperslot,

anditwillnotbepossibletousetheupperslotatall.Many

newerlaptopsincludeonlyasinglePCCardslot,which

accommodatesTypeI,II,orIIIcards.Somemultifunction

network/modemcardshaveanextendedportionwithfull-sized

connectors,suchthateventhoughthecardistechnicallyaType

IorIIcard,theconnectorportionmayprecludeusingtheupper

slot.



Note

ATypeIVPCCard,thickerstillthantheTypeIII,



wasproposedbyToshibaforhigher-capacityPC

Cardbasedharddrives.Thiscardtypewasnever

recognizedbythePCMCIA,however,andhasrarely

beenimplementedinactualsystemsordevices.



APCCardusuallyhasasturdymetalcaseandissealed,except

fortheinterfacetothePCMCIAadapterinthecomputeratone

end,whichconsistsof68tinypinholes.Theotherendofthe

cardmightcontainaconnectorforacableleadingtoa

telephoneline,anetwork,orsomeotherexternaldevice.Type

I,TypeII,andTypeIIIPCCardsarecomparedtoeachotherin

Figure8.1.



Figure8.1.PCCardPhysicalTypes.Oneortwo

TypeIorTypeIIPCCards(uppercenter)canbe

insertedintomostnotebookcomputers(center),

butonlyoneTypeIIIPCCard(upperright)can

beusedatatime(lowercenter).



[Viewfullsizeimage]



ThepinoutsforthePCCardinterfacesareshowninTable8.4.

Table8.4.PCCard-16andCardBusPinouts

Pin



PCCard-16



CardBus



1



GND



GND



2



D3



CAD0



3



D4



CAD1



4



D5



CAD3



5



D6



CAD5



6



D7



CAD7



7



-CE1



CC/-BE0



8



A10



CAD9



9



-OE



CAD11



10



A11



CAD12



11



A9



CAD14



12



A8



CC/-BE1



13



A13



CPAR



14



A14



-CPERR



15



-WE



-CGNT



16



READY/-IREQ



-CINT



17



Vcc



Vcc



18



Vpp/Vcore



Vpp/Vcore



19



A16



CCLK



20



A15



-CIRDY



21



A12



CC/-BE2



22



A7



CAD18



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Chapter 8.  Expansion Card Buses

Tải bản đầy đủ ngay(0 tr)

×