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double-word n-1
acklD rsv
prio
tt ftype
destID
sourcelD
address
rsrv
xamsbs double-word 0
double-word 1
...
double-word n-2
CRC
PHY
LOG
TRA
LOG
TRA
PHY
5
3
2
2
4
8
8
29
1
2
64 64
(n-4)*64
64
64
16
16
n*64+32
16
4
2
10
LOG
PHY
10
TRA
2 4
9 * 6 4 + 32
LOG
TRA
16
PHY
16
double-word 0
5
acklD sourcelDrsv
3
prio
2
ftype
tt
2 4
destiD
8
1
rsrv
address
8 29
xamsbs
2
64
double-word 8
double-word 1
64
5*64
...
64
double-word 9
64
CRC
16
LOG
(n-9)*64
16
PHY
double-word 10
64
double-word n-2double-word 11
64
(n-13)*64
...
double-word n-1
6464
16
CRC
n*64+96
n*64+80
PHY = Physical layer
TRA= Transport layer
LOG = Logical layer
SC or PD parameter1stype0 stype1Parameter0 cmd CRC
533553
Delimiter 1st Byte 2nd Byte 3rd Byte
8
SRIOFunctionalDescription
Figure6.1x/4xRapidIOPacketDataStream(Streaming-WriteClass)
Note:Figure6assumesthataddressesare32-bitanddeviceIDsare8-bit.
ThedeviceID,beingan8-bitfield,willaddressupto256nodesinthesystem.If16-bitaddresseswere
used,thesystemcouldaccommodateupto64knodes.
ThedatastreamincludesaCyclicRedundancyCode(CRC)fieldtoensurethedatawascorrectly
received.TheCRCvalueprotectstheentirepacketexcepttheackIDandonebitofthereservedPHY
field.TheperipheralcheckstheCRCautomaticallyinhardware.IftheCRCiscorrect,aPacket-Accepted
controlsymbolissentbythereceivingdevice.IftheCRCisincorrect,aPacket-Not-Acceptedcontrol
symbolissentsothattransmissionmayberetried.
2.1.2.3ControlSymbols
Controlsymbolsarephysicallayermessageelementsusedtomanagelinkmaintenance,packet
delimiting,packetacknowledgment,errorreporting,anderrorrecovery.Alltransmitteddatapacketsare
delimitedbystart-of-packetandend-of-packetdelimiters.SRIOcontrolsymbolsare24bitslongandare
protectedbytheirownCRC.Controlsymbolsprovidetwofunctions:stype0symbolsconveythestatusof
theporttransmittingthesymbol,andstype1symbolsarerequeststothereceivingportortransmission
delimiters.Theyhavethefollowingformat,whichisdetailedinsection3oftheRapidIOLP-Serial
specification.
Figure7.SerialRapidIOControlSymbolFormat
Controlsymbolsaredelimitedbyspecialcharactersatthebeginningofthesymbol.Ifthecontrolsymbol
containsapacketdelimiter(start-of-packet,end-of-packet,etc.),thespecialcharacterPD(K28.3)isused.
Ifthecontrolsymboldoesnotcontainapacketdelimiter,thespecialcharacterSC(K28.0)isused.This
useofspecialcharactersprovidesanearlywarningofthecontentsofthecontrolsymbol.TheCRCdoes
notprotectthespecialcharacters,butanillegalorinvalidcharacterisrecognizedandflaggedas
Packet-Not-Accepted.Sincecontrolsymbolsareknownlength,theydonotneedenddelimiters.
22SerialRapidIO(SRIO)SPRU976–March2006
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