8B10B_Coding_VS_64B_66B_Coding

8B 10BCoding64B 66BCoding TransmissionSystems8B 10BCoding64B 66BCodingCIPDemonstratorTestSetup TransmissionsystemGeneral Clock Data 1Gbps 1ns 20cm TransmissionsystemPropagationDelay Clock Data Unequalpropagationdelay10cm 1Gbps TransmissionsystemClockDataRecovery Clock Data CDR IfthereareenoughedgesinthedatathentheclockcanberecoveredfromthedatausingaPLL PLL PLL CombineClockandData CodeProperties ProvideenoughedgesinthedatatoenableClockRecovery TransmissionsystemReceiverThreshold Clock Data CDR ReceiverThresholdrefersto Ground whichmustbethesamepotentialas Ground atthetransmitter Jitter UseDifferentialsignalling Transmission Clock Data CDR ReceiverThresholdishalfwaypositiveandnegativesignal Commonmodevoltagedifferencebetweentransmitterandterminationatthereceivercanresultinexcessivecurrents Icm UseACCouplingCapacitors NeedDCBalance 1 DCBalance 1 0 1 0 1 1 0 1 0 1 1 1 1 1 1 1 1 0 DefineamaximumRunLengthSentequalamountof 1 sand 0 s RunningDisparity ReceiverAutomaticGainControl Gain Time Gain Time Again maximumRunLength CodeProperties ProvideenoughedgesinthedatatoenableClockRecoveryMaximumRunLengthandDCBalance Historyof8B 10Bcoding 8B 10Bcoding Maximumrunlength 5RunningDisparity DCBalance8bits 256differentvalues10bits 1024differentvalues8B10Bcodeisbuiltoutof 5to6bitcode 3to4bitcode 8B 10Bcoding Notall1024valuesareuseful Forexample 0100000011 hasrunlength6Formostofthe256 8B valuesapositiveandanegative10Bvalueisselecteddependingonthe CurrentRunningDisparity Forexample D7 0 1110001011 CurrentRD D7 0 0001110100 CurrentRD Soabout512usefulvaluesareselectedfrom1024 Therearestillafewcodesleft 8B 10Bcodingtable 256 Data Characters 8B 10Bcodingtable Therewerestillafewcodesleft 12 Special KCharacters CommaCharacters Theonlypatternsthathave5consecutive 1 sor 0 s 010101001101100111000001010110111010010100100111010011001001110100111001 8B 10Bcode K Characters CommacharactersK28 1 K28 5 K28 7areusedwordalignment 010101001101100111000001010110111010010100100111010011001001110100111001 D31 3 D11 3 D0 0 K28 5 D16 2 Create orderedsets ForexampleFibreChannelStartOfFrame SOF K28 5 D21 5 D23 0 D23 0K30 7 ErrorPropagateK28 3 CarrierExtend 8B 10Bcodeproperties ProvideenoughedgesinthedatatoenableClockRecoveryMaximumRunLengthandDCBalanceAddspecialcharactersCommaforwordalignmentControlcharacters 64B 66BCoding 64B 66B IEEEstd802 3ae 2002 Clause49 20 ofthebandwidthfor8B 10BisoverheadFor64B 66Boverheadis3 2bitSyncHeader 64bit Scrambled 2bitSyncHeader00CodeError0164bit Datafield1064bit MixedData Controlfield11CodeError Onceevery66bitsthereisatleasta 01 ora 10 transition ReceiverBlockSync itmaytakeawhile 64B 66BScrambler Scrambler X58 X39 1Triestomixupthedatatoavoidlongsequencesof 1 sand 0 sNote thereisnoguaranteethatonabaddaytheoutputofthescramblerproducesall 0 sorall 1 s 1 0 D0 8 D1 8 D2 8 D3 8 D4 8 D5 8 D6 8 D7 8 64B 66B 0 1 64bitDataField Scrambled Typ 8 Z0 7 Z1 7 Z2 7 Z3 7 Z4 7 Z5 7 Z6 7 1 0 64bitMixedControl DataField Scrambled Z7 7 PureControl Type 0 x1E Typ 8 1 0 MixedControl Data Type 0 x87 T0 Typ 8 Z2 7 Z3 7 Z4 7 Z5 7 Z6 7 Z7 7 1 0 Typ 8 Z3 7 Z4 7 Z5 7 Z6 7 1 0 Z7 7 Typ 8 Z4 7 Z5 7 Z6 7 1 0 Z7 7 Typ 8 Z5 7 Z6 7 1 0 Z7 7 Typ 8 Z6 7 Z7 7 7 Z1 7 Z2 7 Z3 7 Z4 7 Z5 7 Z6 7 Z7 7 6 D0 8 D0 8 D1 8 5 D0 8 D1 8 D2 8 4 D0 8 D1 8 D2 8 D3 8 3 D0 8 D1 8 D2 8 D3 8 D4 8 2 Totalof15MixedControl DataFieldisdefined MixedControl Data Type 0 x99 T1 MixedControl Data Type 0 xaa T2 MixedControl Data Type 0 xb4 T3 MixedControl Data Type 0 xcc T4 MixedControl Data Type 0 xd2 T5 etc PureData 2bitSyncHeader 64bit Scrambled 64B 66BExample 0 1 Z5 Z6 Z7 D0 D1 D2 D3 D4 D5 D6 D7 T 1 0 D0 D1 D2 Z4 Z5 Z6 Z7 Transmittingasequenceof18bytescouldlooklike T 1 0 D1 D2 D3 D4 D5 D6 D7 0 x78 S0Start 0 xB4 T3Terminate PureDataFrame 64B 66BPhysicalCodingSublayer PCS Transmitbitordering Tx Data 0 Tx Data 15 GearboxAdaptsbetween 4x16 64bitwidthand66bitwidthframes Comparison CIPDemonstratorTestSetup CIPTestBed Delay Tx8B 10BEncoded Rx8B 10BEncoded CIPDemonstratorTestSetup K28 5 D16 2 K23 7 Dx y IDLE CharExt Tx8B 10BEncoded K28 5 D16 2 K28 5 D16 2 IDLE IDLE K28 5 D16 2 K28 5 D16 2 IDLE IDLE K28 5 D16 2 K23 7 Dx y IDLE CharExt K28 5 D16 2 K28 5 D16 2 IDLE IDLE K28 5 D16 2 IDLE K28 5 D16 2 IDLE Start Stop StanfordResearch 2x10Kmfiber 100us2x100Kmfiber 1ms 100Hz Rx8B 10BEncoded FirstRe