
5.2Single-andMultiple-ByteTransfers
5.3Single-ByteWrite
A6 A5 A4 A3 A2 A1 A0
R/W
ACK A7 A6 A5 A4 A3 A2 A1 A0 ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK
Start
Condition
Stop
Condition
Acknowledge Acknowledge Acknowledge
I CDevice Addressand
2
Read/WriteBit
Subaddress DataByte
T0036-01
TAS5518C
8-ChannelDigitalAudioPWMProcessor
SLES238A–SEPTEMBER2008–REVISEDJULY2009
www.ti.com
Theserial-controlinterfacesupportsbothsingle-byteandmultiple-byteread/writeoperationsforstatus
registersandthegeneralcontrolregistersassociatedwiththePWM.However,fortheDAPdata
processingregisters,theserial-controlinterfacesupportsonlymultiple-byte(four-byte)read/write
operations.
Duringmultiple-bytereadoperations,theTAS5518Crespondswithdata,abyteatatime,startingatthe
subaddressassigned,aslongasthemasterdevicecontinuestorespondwithacknowledges.Ifa
particularsubaddressdoesnotcontain32bits,theunusedbitsarereadaslogic0.
Duringmultiple-bytewriteoperations,theTAS5518Ccomparesthenumberofbytestransmittedtothe
numberofbytesthatarerequiredforeachspecificsubaddress.Ifawritecommandisreceivedfora
biquadsubaddress,theTAS5518Cexpectstoreceivefive32-bitwords.Iffewerthanfive32-bitdata
wordshavebeenreceivedwhenastopcommand(oranotherstartcommand)isreceived,thedata
receivedisdiscarded.Similarly,ifawritecommandisreceivedforamixercoefficient,theTAS5518C
expectstoreceiveone32-bitword.
SupplyingasubaddressforeachsubaddresstransactionisreferredtoasrandomI
2
Caddressing.The
TAS5518CalsosupportssequentialI
2
Caddressing.Forwritetransactions,ifasubaddressisissued
followedbydataforthatsubaddressandthe15subaddressesthatfollow,asequentialI
2
Cwrite
transactionhastakenplace,andthedataforall16subaddressesissuccessfullyreceivedbythe
TAS5518C.ForI
2
Csequentialwritetransactions,thesubaddressthenservesasthestartaddressandthe
amountofdatasubsequentlytransmitted,beforeastoporstartistransmitted,determineshowmany
subaddressesarewritten.Asistrueforrandomaddressing,sequentialaddressingrequiresthata
completesetofdatabetransmitted.Ifonlyapartialsetofdataiswrittentothelastsubaddress,thedata
forthelastsubaddressisdiscarded.However,allotherdatawrittenisaccepted;onlytheincompletedata
isdiscarded.
AsshowninFigure5-2,asingle-byte,data-writetransferbeginswiththemasterdevicetransmittingastart
conditionfollowedbytheI
2
Cdeviceaddressandtheread/writebit.Theread/writebitdeterminesthe
directionofthedatatransfer.Forawritedatatransfer,theread/writebitisa0.Afterreceivingthecorrect
I
2
Cdeviceaddressandtheread/writebit,theTAS5518Cdevicerespondswithanacknowledgebit.Next,
themastertransmitstheaddressbyteorbytescorrespondingtotheTAS5518Cinternalmemoryaddress
beingaccessed.Afterreceivingtheaddressbyte,theTAS5518Cagainrespondswithanacknowledgebit.
Next,themasterdevicetransmitsthedatabytetobewrittentothememoryaddressbeingaccessed.After
receivingthedatabyte,theTAS5518Cagainrespondswithanacknowledgebit.Finally,themaster
devicetransmitsastopconditiontocompletethesingle-byte,data-writetransfer.
Figure5-2.Single-ByteWriteTransfer
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I
2
CSerial-ControlInterface(SlaveAddresses0x36and0x37)
Not Recommended For New Designs