Datasheet

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TAS3108,TAS3108IA
AUDIODIGITALSIGNALPROCESSORS
SLES152B–OCTOBER2005–REVISEDNOVEMBER2007
Oncethemicroprocessorprogrammemoryhasbeenloaded,itcannotbereloadeduntilthe
TAS3108/TAS3108IAhasbeenreset.
Ifanerrorisencountered,TAS3108/TAS3108IAterminatesitsmemory-loadoperation,loadsthedefault
configuration,anddisablesfurthermasterI
2
Cbusoperations.
Ifanend-of-programdatablockisread,theTAS3108/TAS3108IAhascompletedtheinitialprogramload.
TheI
2
CmastermodeusesthestartingandendingI
2
CchecksumstoverifyaproperEEPROMdownload.
Thefirst16-bitdatawordreceivedfromtheEEPROM,theI
2
Cchecksumatsubaddress0x00,isstored
andcomparedagainstthe16-bitdatawordreceivedforthelastsubaddress,theendingI
2
Cchecksum,
andthechecksumthatiscomputedduringthedownload.Thesethreevaluesmustbeequal.Iftheread
andcomputedvaluesdonotmatch,theTAS3108/TAS3108IAsetsthememoryreaderrorbitsinthe
statusregisterandrepeatsthedownloadfromtheEEPROMtwomoretimes.Ifthecomparisoncheckfails
thethirdtime,theTAS3108/TAS3108IAsetsthemicroprocessorprogramtothedefaultvalue.
Table6-5showstheformatoftheEEPROMorotherexternalmemoryloadfile.Eachlineofthefileisa
byte(inASCIIformat).Thechecksumisthesummationofallthebytes(withbeginningandending
checksumfields=00).Thefinalchecksuminsertedintothechecksumfieldisthelowestsignificantfour
bytesofthechecksum.
Example:
Giventhefollowingexample8051dataorprogramblock(mustbeamultipleof4bytesfortheseblocks):
10h
20h
30h
40h
50h
60h
70h
80h
Thechecksum=10h+20h+30h+30h+40h+50h+60h+70h+80h=240h,so
thevaluesputinthechecksumfieldsareMSbyte=02handLSbyte=40h.
Ifthechecksumis>FFFFh,the2-bytechecksumfieldistheleast-significanttwobytes.
Forexample,ifthechecksumis1D45B6h,thechecksumfieldisMSbyte=45handLSbyte=B6h.
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