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3.6on-chipperipherals
3.6.1software-programmablewait-stategenerator
TMS320VC5409A
fixed-pointdigitalsignalprocessor
SPRS140F–NOVEMBER2000–REVISEDJANUARY2005
the5409adevicehasthefollowingperipherals:
•
软件-programmablewait-stategenerator
•
programmablebank-切换
•
ahost-portinterface(hpi8/16)
•
threemultichannelbufferedserialports(mcbsps)
•
Ahardwaretimer
•
aclockgeneratorwithamultiplephase-lockedloop(pll)
•
enhancedexternalparallelinterface(xio2)
•
admacontroller(dma)
thesoftwarewait-stategeneratorofthe5409acanextendexternalbuscyclesbyuptofourteenmachine
循环.devicesthatrequiremorethanfourteenwaitstatescanbeinterfacedusingthehardwareready
线条.whenallexternalaccessesareconfiguredforzerowaitstates,theinternalclockstothewait-状态
generatorareautomaticallydisabled.disablingthewait-stategeneratorclocksreducesthepower
consumptionofthe5409a.
thesoftwarewait-stateregister(swwsr)controlstheoperationofthewait-stategenerator.the14lsbs
oftheswwsrspecifythenumberofwaitstates(0to7)tobeinsertedforexternalmemoryaccessesto
fiveseparateaddressranges.thisallowsadifferentnumberofwaitstatesforeachofthefiveaddress
范围.additionally,thesoftwarewait-statemultiplier(swsm)bitofthesoftwarewait-statecontrol
寄存器(swcr)definesamultiplicationfactorof1or2forthenumberofwaitstates.atreset,这
wait-stategeneratorisinitializedtoprovidesevenwaitstatesonallexternalmemoryaccesses.这
swwsrbitfieldsareshowninfigure3-5anddescribedintable3-3.
1514121198
xpai/odatadata
r/w-0r/w-111r/w-111r/w-111
765320
DataProgramProgram
r/w-111r/w-111r/w-111
legend:r=读,w=写,n=valueatreset
figure3-5.softwarewait-stateregister(swwsr)[memory-mappedregister(mmr)地址
0028h]
table3-3.softwarewait-stateregister(swwsr)fielddescriptions
BITFIELDVALUEDESCRIPTION
extendedprogramaddresscontrolbit.xpaisusedinconjunctionwiththeprogramspacefields(bits0
15XPA0
through5)toselecttheaddressrangeforprogramspacewaitstates.
i/ospace.thefieldvalue(0-7)correspondstothebasenumberofwaitstatesfori/ospaceaccesses
14-12i/o111withinaddresses0000-ffffh.theswsmbitoftheswcrdefinesamultiplicationfactorof1or2for
thebasenumberofwaitstates.
upperdataspace.thefieldvalue(0-7)correspondstothebasenumberofwaitstatesforexternal
11-9data111dataspaceaccesseswithinaddresses8000-ffffh.theswsmbitoftheswcrdefinesa
multiplicationfactorof1or2forthebasenumberofwaitstates.
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FunctionalOverview
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