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2.3.10ResetandPowerDown
SRIOFunctionalDescription
TheRapidIOperipheralallowsindependentsoftwarecontrolledshutdownforthelogicalblockslistedin
Table26.WiththeexceptionofBLK0_ENforthememory-mappedregisters(MMRs),whentheBLKn_EN
signalsaredeasserted,theclocksaregatedtotheseblocks,effectivelyprovidingashutdownfunction.
Table26.ResetHierarchy
BusGBLBLK0BLK1BLK2BLK3BLK4BLK5BLK6BLK7BLK8
LogicalBlockReset_EN_EN_EN_EN_EN_EN_EN_EN_EN_EN
DMAinterface√√
MMRs:√√
Reset/power-
downcontrol
registers
MMRs:√√√
Non-reset/power-
downcontrol
registers
Interrupthandling√√
unit(IHU)
Trafficflowlogic√√
Congestion√√
controlunit
(CCU)
LSU(DirectI/O√√√
initiator)
MAU(DirectI/O√√√
target)
TXU(message√√√
passinginitiator)
RXU(message√√√
passingtarget)
Port0datapath√√√
Port1datapath√√√
Port2datapath√√√
Port3datapath√√√
ResetoftheSERDESmacrosishandledindependentlyoftheregistersdiscussedinthissection.The
SERDEScanbeconfiguredtoshutdownunusedlinksorfullyshutdown.SERDESTXandRXchannels
maybeenabled/disabledbywritingtobit0oftheSERDES_CFGTXn_CNTLand
SERDES_CFGRXn_CNTLregisters.ThePLLandremainingSERDESfunctionalblockscanbecontrolled
bywritingtotheENPLLsignalintheSERDES_CFG0_CNTLregister.ThisbitwilldrivetheSERDES
signalinput,whichwillgatethereferenceclocktotheseblocksinternally.Thisreferenceclockissourced
fromadevicepinspecificallyfortheSERDESandisnotderivedfromtheCPUclock,thusitresets
asynchronously.ENPLLwilldisableallSERDEShigh-speedoutputclocks.Sincetheseclocksare
distributedtoallthelinks,ENPLLshouldonlybeusedtocompletelyshutdowntheperipheral.Itshouldbe
notedthatshutdownofSERDESlinksinbetweennormalpackettransmissionsisnotpermissiblefortwo
reasons.First,theserialRapidIOsendsidlepacketsbetweendatapacketstomaintainsynchronization
andlanealignment.Withoutthismechanism,theRapidIORXlogiccanbemis-alignedforboth1Xand4X
ports.Second,thelocktimeoftheSERDESPLLwouldneedtoreoccur,whichwouldslowdownthe
operation.
WhentheSERDESENTXsignalisheldlow,thecorrespondingtransmitterispowereddown.Inthisstate,
bothoutputs,TXPandTXN,willbepulledhightoVDDT.
70SerialRapidIO(SRIO)SPRUE13A–September2006
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