10.4.2.2SynchronousReset(SyncReset)
DSPReset
•Host:AsserttheDSPlocalreset(Optional)
–CleartheLRSTbitinMDCTL39to0.Thisstepisoptional.ThisstepassertstheDSPlocalreset,and
isincludedheresothattheDSPdoesnotstartrunningimmediatelyuponitissubsequentlyenableby
thehost.Typically,thehostonlyde-assertslocalresettotheDSPafteritmakessurethatcodeis
properlyloaded.
Inthesynchronousreset(SyncReset)state,theDSP’smoduleresetisassertedanditsmoduleclockis
enabled.YoucanusethisstatetoresettheDSP.ThefollowingstepsdescribehowtoputtheDSPinthe
synchronousresetstate:
•Host:NotifytheDSPtoprepareforpower-down.
•DSP:PuttheDSPintheIDLEstate.
–SetPDCCMDto00015555h.PDCMDisacontrolregisterintheDSPpower-downcontroller
module.
Note:ThisregistercanonlybewrittenwhiletheDSPisinsupervisormode.
–ExecutetheIDLEinstruction.
•Host:SyncresetDSP
–WaitfortheGOSTAT[0]bitinPTSTATtoclearto0.Youmustwaitforthepowerdomaintofinish
anypreviouslyinitiatedtransitionsbeforeinitiatinganewtransition.
–SettheNEXTbitinMDCTL39to1topreparetheDSPmoduleforaSyncResettransition.
–SettheGO[0]bitinPTCMDto1toinitiatethestatetransition.
–WaitfortheGOSTAT[0]bitinPTSTATtoclearto0.Themoduleissafelyinthenewstateonly
aftertheGOSTAT[0]bitisclearedto0.
•Host:AssertDSPlocalreset(Optional)
–CleartheLRSTbitinMDCTL39to0.Thisstepisoptional.ThisstepassertstheDSPlocalreset
andisincludedheresothattheDSPdoesnotstartrunningimmediatelyuponitissubsequently
enabledbythehost.Typically,softwarede-assertslocalresettotheDSPafteritmakessurethat
codeisproperlyloaded.
94ResetSPRU978E–March2008
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