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7.4EnhancedDirectMemoryAccess(EDMA3)Controller
7.4.1EDMA3Device-SpecificInformation
TMS320C6454
Fixed-PointDigitalSignalProcessor
SPRS311A–APRIL2006–REVISEDDECEMBER2006
TheprimarypurposeoftheEDMA3istoserviceuser-programmeddatatransfersbetweentwo
memory-mappedslaveendpointsonthedevice.TheEDMA3servicessoftware-drivenpagingtransfers
(e.g.,datamovementbetweenexternalmemoryandinternalmemory),performssortingorsubframe
extractionofvariousdatastructures,serviceseventdrivenperipheralssuchastheMcBSP,andoffloads
datatransfersfromthedeviceCPU.
TheEDMA3includesthefollowingfeatures:
•Fullyorthogonaltransferdescription
–3transferdimensions:array(multiplebytes),frame(multiplearrays),andblock(multipleframes)
–Singleeventcantriggertransferofarray,frame,orentireblock
–Independentindexesonsourceanddestination
•Flexibletransferdefinition:
–IncrementorFIFOtransferaddressingmodes
–Linkingmechanismallowsforping-pongbuffering,circularbuffering,andrepetitive/continuous
transfers,allwithnoCPUintervention
–Chainingallowsmultipletransferstoexecutewithoneevent
•256PaRAMentries
–Usedtodefinetransfercontextforchannels
–EachPaRAMentrycanbeusedasaDMAentry,QDMAentry,orlinkentry
•64DMAchannels
–Manuallytriggered(CPUwritestochannelcontrollerregister),externaleventtriggered,andchain
triggered(completionofonetransfertriggersanother)
•8QuickDMA(QDMA)channels
–Usedforsoftware-driventransfers
–TriggereduponwritingtoasinglePaRAMsetentry
•4transfercontrollers/eventqueueswithprogrammablesystem-levelpriority
•Interruptgenerationfortransfercompletionanderrorconditions
•Memoryprotectionsupport
–ActivememoryprotectionforaccessestoPaRAMandregisters
•Debugvisibility
–Queuewatermarking/thresholdallowsdetectionofmaximumusageofeventqueues
–Errorandstatusrecordingtofacilitatedebug
Eachofthetransfercontrollershasadirectconnectiontotheswitchedcentralresource(SCR).Table4-1
liststheperipheralsthatcanbeaccessedbythetransfercontrollers.
ADSPinterruptmustbegeneratedattheendofanHPIorPCIbootoperationtobeginexecutionofthe
loadedapplication.SincetheDSPinterruptgeneratedbytheHPIandPCIismappedtotheEDMAevent
DSP_EVT(DMAchannel0),itwillgetrecordedinbit0oftheEDMAEventRegister(ER).Thiseventmust
beclearedbysoftwarebeforetriggeringtransfersonDMAchannel0.TheEDMA3ontheC6454DSP
supportsactivememoryprotection,butitdoesnotsupportproxiedmemoryprotection.
TheEDMAsupportstwoaddressingmodes:constantaddressingandincrementaddressingmode.Onthe
C6454DSP,constantaddressingmodeisnotsupportedbyanyperipheralorinternalmemory.Formore
informationonthesetwoaddressingmodes,seetheTMS320C645xDSPEnhancedDMA(EDMA)
ControllerUser'sGuide(literaturenumberSPRU966).
C64x+PeripheralInformationandElectricalSpecifications 98SubmitDocumentationFeedback