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4.14VideoDisplayFIFORegisters
VideoDisplayFIFORegisters
ThedisplayFIFOmappingregistersarelistedinTable4-35.TheseregistersprovideEDMAwriteaccess
tothedisplayFIFOs.Thesepseudo-registersshouldbemappedintoDSPmemoryspaceratherthan
configurationregisterspaceinordertoprovidehigh-speedaccess.Seethedevice-specificdatasheetfor
thememoryaddressoftheseregisters.
ThefunctionofthevideodisplayFIFOmappingregistersislistedinTable4-36.
Table4-35.VideoDisplayFIFORegisters
OffsetAddress
(1)
AcronymRegisterName
80hYDSTAYFIFODestinationRegisterA
a0hCBDSTACbFIFODestinationRegisternA
c0hCRDSTACrFIFODestinationRegisterA
80hYDSTBYFIFODestinationRegisterB
a0hCBDSTBCbFIFODestinationRegisterB
c0hCRDSTBCrFIFODestinationRegisterB
(1)
Theabsoluteaddressoftheregistersisdevice/portspecificandisequaltotheFIFObaseaddress
+offsetaddress.Seethedevice-specificdatasheettoverifytheregisteraddresses.
Table4-36.VideoDisplayFIFORegistersFunction
DisplayMode
RegisterBT.656orY/CRawData
YDSTxMapsYdisplayFIFOintotheDSPmemory.MapsdatadisplaybufferintotheDSPmemory.
CBDSTMapsCbdisplayFIFOintotheDSPmemory.Notused.
CRDSTMapsCrdisplayFIFOintotheDSPmemory.Notused.
InBT.656orY/Cdisplaymode,threeEDMAsmovedatafromtheDSPmemorytoY,Cb,andCrdisplay
FIFOsbyusingthememory-mappedYDSTx,CBDST,andCRDSTregisters.TheEDMAtransfersare
triggeredbytheYEVT,CbEVT,andCrEVTevents,respectively.
Inrawdisplaymode,oneEDMAchannelmovesdatafromtheDSPmemorytotheYdisplayFIFOby
usingthememory-mappedYDSTxregister.TheEDMAtransfersaretriggeredbyaYEVTevent.
ThevideodisplayFIFOregistersarewrite-onlylocations.Readsoftheseaddressesreturnsarbitrary
valuesanddonotaffectthestatusofthedisplayFIFOs.
SPRUEM1–May2007VideoDisplayPort149
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