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9.2.1.5OutputParametersTransfer
9.2.2InputConfigurationsParametersProgramming
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Programming
3.NullEDMA3transferparameters(withallzeros),iftherearenomoreuserchannelsreadytobe
decodedandtheOUTFbitiscleared.
ThisEDMA3transferisoptionalanddependsontheOUTFbitintheTCP2inputconfigurationregister0
(TCPIC0).ThisEDMA3transferisaTCPREVTframe-synchronizedtransfer.Theparametersshouldbe
setas:
•OPTIONS:
–ITCCEN=0(Intermediatetransfercompletechainingisdisabled)
–TCCEN=0(Transfercompletechainingisdisabled)
–ITCINTEN=0(Intermediatetransfercompleteinterruptisdisabled)
–TCINTEN=1(Transfercompleteinterruptisenabled)
–TCC=1to63(TransferCompleteCode)
–TCCMODE=0(NormalCompletion)
–FWID=Don'tcare
–STAT=0(Entryisupdatedasnormal)
–SYNCDIM=0(A-Sync.EacheventtriggersthetransferofACNTelements.)
–DAM=0(Dstaddressingwithinanarrayincrements.DstisnotaFIFO)
–SAM=0(Srcaddressingwithinanarrayincrements.SourceisnotaFIFO.)
•SOURCEADDRESS:TCPOUT(50000030h)
•ACNT=12(Noofbytesinanarray)
•BCNT=1(NoofarraysoflengthACNT)
•DESTINATIONADDRESS:Useroutputparametersstartaddress(mustbedouble-wordaligned)
•SRCBIDX=0(Source2ndDimensionIndex)
•DSTBIDX=0(Destination2ndDimensionIndex)
•SRCCIDX=0(Source3rdDimensionIndex)
•DSTCIDX=0(Destination3rdDimensionIndex)
•CCNT=1(Noofframesinablock)
•BCNTRLD:Don'tcare
•LINKADDRESS:Seecases1and2below
Uponcompletion,thisEDMA3transferislinkedtooneofthefollowing:
1.TheharddecisionsEDMA3transferparametersofthenextuser-channel,ifthereisonereadytobe
decoded.
2.NullEDMA3transferparameters(withallzeros),iftherearenomoreuser-channelsreadytobe
decoded.
Theframelength(FLbitsinTCPIC0)shouldbesettothenumberofinformationbits(priorto
turbo-encodingandnotincludingtherateorthetailbits).
Thenumberofsub-blocks(NSBbitsinTCPIC2),thereliabilitylength(RbitsinTCPIC1),andtheprolog
size(PbitsinTCPIC2)shouldbesetasdescribedinSection8.3.Itshouldbenotedthata1mustbe
subtractedfromthecalculatedRvaluepriortowritingtoTCPIC1.
Themaximumnumberofiterations(MAXITbitsinTCPIC2)shouldbeselectedasafunctionoftheoverall
systemperformance.Avalue0setsthemaximumnumberofiterationstoitsmaximum(32).
TheSNRthresholdratio(SNRbitsinTCPIC2)shouldbeselectedasafunctionoftheoverallsystem
performance.Avalue0disablesthestoppingcriteriaalgorithm.
TheEMAXSTRbitcanbeenabledordisabledinTCPIC3(0=maxstardisabled(enableMaxLog-MAP)1
=maxstarenabled(enablelogMAP)).
SPRUGK1–March2009TMS320C6457Turbo-DecoderCoprocessor269
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