NFC/HF RFID Reader/Writer Using the TRF7970A …

1 1 SLOA227A October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 AApplicationReportSLOA227A October2015 RevisedDecember2016 NFC/HFRFIDR eader/WriterUsingthe TRF7970 AErickMacias,RalphJacobi, NearFieldCommunication(NFC)marketis emerginginto multiplefieldsincludingmedical,consumer, retail,industrial,automotive, oneof the threeoperationalmodessupportedby the TRF7970A . WhenusingReader/Writermodethe usercan configurethe TRF7970 AtoreadType2, Type3, Type4A, Type4B, and Type5 tag platforms,also tags canstoreNFCDataExchangeFormat(NDEF)messa gesor fundamentalconceptsof reader /Writermodeand howto properlyconfigurethe TRF7907 Atransceiverfor ,it describeshowtosuccessfullyactivate,selec t,and reador examplefirmwarefocuseson exampleswherethe userpresentsonly one tagat a ,it is possiblefrombotha hardwareand firmwarestandpointto readmultipletagsatthe applicationsthat use only reader /Writermode,the TRF7964 Acan be usedas a drop-inalternativetothe this documentcan October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 AContents1 Terms,Definitions,and of PHY( TRF7970A ).

2 ActivationProcessfor Type4A DeterminingType5 Tag Type2 TagsWitha Type2 TagsWitha Type3 Tag Tag NDEFFile Examplefor Type4 Type5 and and of Tables1 NFC/RFIDTagsSupportedby + October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970A4 TRF7970 ATB+ + MSP-EXP432P401 RLaunchPadDevelopmentKit NFC/RFIDTag ,LaunchPad,EnergyTrace+are trademarksof othertrademarksare the propertyof e a k F m in im u mp e a k + m in im u m o r 1 F b1 + b Terms,Definitions,and October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970A1 Terms,Definitions,and SymbolsALL_REQNFC-APollingcommand,equiva lentto ISO14443-3shortframecommandWupA(0x52)ALL B_REQNFC-BPollingcommand,equivalentto ISO14443-3commandWupBAPDUA pplicationProtocolDataUnit, usedin command-responsepairsto exchangeI (information),R (receiveready)or S (supervisory) ,TypeBATQAA nswerTo ReQuestA,ISO14443-3term,equivalentto NFCtermSENS_RESATQBA nswerTo ReQuestB,ISO14443-3term,equivalentto NFCtermSENSB_RESCCC apabilityContainer,containsmanagementdat aand is storedinsidea read-onlyEF file.

3 This EF islocatedinsidethe NDEFtag (or basic)file ID for this file (for NFC)is Tag OperationSpecificationand ISO/IEC7816-4for ,one of the threemodesofferedby this optionalmodeof NFCoperation,an NFCF orumdeviceis consideredto be a cardemulationplatformonly whenit is emulatinga Type3,Type4A or Type4B Tag any othercardsor tags is outsidethe scopeof the ,an abstractedoperationallayerthat is usingeitherISO or ,two termscan be createdwith this acronym:ISO-DEPand the contextof this document,afteractivationand selectionof the emulatedcardand beforedeactivation,ISO-DEPisusedexclusiv elyto exchangedatabetweenReader/ writer (PCD)and Tag Platform(PICC).EFElementaryFile, a set of dataobjects,recordsor unitssharingthe samefile identifierand the samesecurityattributesFile IdentifierTwo byte dataelementusedto addressa filefcCarrierfrequency,in the contextof NFC/HFRFID,is 7 is the fundamentaltransmitfrequencyof the Reader/Writer (alsocalledPCD)InitiatorGen eratorof the RF field and sourceof the beginningof the NFCIP-1communicationMIMEM ultipurposeInternetMailExtensionsModulat ionIndex,mSignalamplituderatioof, wherebis the ratiobetweenthe modulatedamplitudeand the indexmis definedper protocoltype for bothdownlinkanduplinkand is generallyexpressedas a percentage(for example,TypeA usesm= 100%,and TypeBusesm= 8 to 14%).

4 ,Definitions,and Symbols5 SLOA227A October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 APCBP rotocolControlByte, usedfor conveyinginformationrequiredto controldatatransmissionof blocksduringthe exchangeof codingof this byte and use rulesare (alsocommonlyreferredto as Reader/Writer )PICCP roximityIntegratedCircuitCard (alsocommonlyreferredto as tag, tag platformor transponder)PUPIP seudoUniquePICCI dentifier(randomlygeneratedor staticnumberreturnedby PICCas part of theresponseto REQB,WupB,ALLB_REQor SENSB_REQ)RTDR ecordTypeDefinitionSAKS electAcKnowledge(fromISO14443-3),in NFCtermsthis is also calledSEL_RESSDD_RESE quivalentto ISO14443-3responseto SDD_REQ,and is completeNFCID1 CLn + BCC(if cascadelevel1 (singlesize UID)or indicatesNFCID1is incompletein the responseand furthercascadelevelsmustbecompletedto obtaincompleteNFCID1+ ISO14443-3 TypeA SEL_CMD,SEL_PARand n databits codedbasedon cascadelevelspecifiedby SEL_CMDand calculatedby valueof SEL_PARSEL_RESE quivalentto ISO14443-3 SAKresponseSENS_REQNFC-APollingcommand,e quivalentto ISO14443-3shortframecommandREQ_A(0x26))

5 SENS_RESNFC-APollingResponse,equivalentt o ISO14443-3 ATQASENSB_REQNFC-BPollingcommand,equival entto ISO14443-3commandREQ_BSENSB_RESNFC-BPoll ingcommandresponse,equivalentto ISO14443-3 ATQBSENSF_REQNFC-FPollingcommandSENSF_RE SNFC-FPollingresponseSingleDeviceDetecti on(SDD)Algorithmusedby the reader /Writerto detectone out of severaltargetsin its RF field (TypeAanticollision,fromISO/IEC14443-3)T 2 TType2 TagT3 TType3 TagT4 TType4 TagT5 TType5 TagTagSee Tag PlatformTerms,Definitions,and October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 ATag PlatformRespondsto Reader/Writer (PCD)commandsby usingload modulationscheme(passiveoperation)Throug houtthis document,the termstag,tag platform, andtransponderall havethe Tag October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970A2 IntroductionThe TRF7970 Adevicesupportsthreemodes: Reader/Writer , CardEmulation,and Peerto how to use the TRF7970 Ain modeallowsan NFCenabledsystemto activateand readexistingRFID/ the caseof the TRF7970A ,it is possibleto readType2 (T2T),Type3 (T3T),Type4A or B (T4T),and ISO15693(T5T)tag to checkif a tag or NFCpeeris presentevery500 ms.

6 This time is knownas the periodtime,whichincludesthe time the transceiveris polling(searchingfor a tag) plus the time the transceiveris listeningto be activated(in the caseit is emulatingatag or is in Peerto PeerTargetmode).In Figure1, for example,the transceiveris first pollingfor ActiveAand F technology(ActivePeer-to-Peer).Next,it pollsfor passiveA technology(ISO14443A-3),passiveB(ISO1444 3B-3),passiveF (ISO18092),and thenpassiveV (ISO15693).For moreinformationon ActivePeer-to-Peercommunicationand how passiveA and F technologycan beusedto activatepeer-to-peercommunication,seeNFC A ctiveand PassivePeer-to-PeerCommunicationUsingthe NFCT ransceiverPollingSequenceExampleThe Readeralwaysgeneratesthe RF field and the tag load modulatesthe RF field to showsthe NFC/ rfid layersusedto readand and T4 TAplatformsusetechnologyISO14443-3(TypeA ) at an initialbit rate of 106 kbpsfor tag (TypeB)

7 At an initialbit rate of 106 kbpsfor tag activationprocessis completed,bothT4 TAand T4 TBplatformsuse ISO7816-4and ISODEP layersto reador writethe tag T2T platformis activatedit usesT2T commandsto reador writethe tag platformsuse technologyISO18092at an initialbit rate of 212 kbpsor 424 kbpsfor tag T3T is activatedit usesT3T commandsto reador writethe tag platformsusetechnologyISO15693for activationand to readthe tag 14443 B-3 ISO15693-3 ISO 18092 = NFCIP1 ISO 14443 A-3 ISO 7816-4+ISODEPISO 14443-4 NFC Data Exchange Format(NDEF)Type 4 A/B TagNFC/ rfid Transceiver TRF7970 AType 2 TagT2T commandsMIFARE UltralightType 3 TagType 5 TagT3T commandsFeliCa-LiteISO15693 October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 AFigure2.

8 reader /WriterLayersIncludingthe PHY( TRF7970A )A 16-bitand a 32-bitmicrocontrollerwereusedto interfacewith the TRF7970 Ato demonstrateareferenceexampleof the firmwaresupportsflexiblefunctionsthat allowthe userto enableor disablereadingT2T,T3T,T4TA/B,and T5T ,the firmwareprovidessupportfor NFC-enabledsmartphonesthat can emulatetag firmwarecan activateandselectNFC-enabledsmartphones, allowingusersto readcarddataby creatingtheirown lists the NFC/ rfid technologiesthat the :Type1 tags are not ISO compliantand requirethe use of DirectMode0 (DM0)to receiveraw RF to this, the firmwareexampledoesnot NFC/RFIDTagsSupportedby reader /WriterModeTag TechnologySupportType1 Type2 Type3 Type4A Type4B Type5 Collision9 SLOA227A October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970A3 InitialRF CollisionNFCenabledsystemscan supportbothReader/Writermodeand ensurethat two NFCR eaderdevicesdo not sendcommandsat the sametime,an initialRF collisiondetectionis externalReceivedSignalStrengthIndicator( RSSI)

9 Valuethat measuresthestrengthof the demodulatedsubcarriersignalbeforeenablin gits own RF the RSSI valueis greaterthan0x00,it will not enableits RF relationbetweenthe 3-bitcodeand the externalRF field strength(A/m)sensedby the antennamustbe determinedby calculationor by experimentsfor antennaQ-factor,couplingfactorbetweenthe two antennasand connectionto the RF inputinfluencethe throughFigure6 providethe correlationof the free spacedistancebetweentwo unmodifiedTRF7970 ATBmodulesand the 3-bitexternalRSSI valuein threedirections(seeFigure3 for moredetailson eachorientation).One TRF7970 Ahas its RF field at full power(+5 V), and the secondTRF7970 Ais usedto take RSSIL evelMeasurementOrientations01234567890x0 0 0x01 0x02 0x03 0x04 0x05 0x06 0x07 Distance Between Atnennas (cm)RSSI Levels and OScillator Status Register Value (0x0F)01234567890x000x010x020x030x040x05 0x060x07 Distance Between Antennas (cm)RSSI Levels and Oscillator Status Register Value (0x0F)01234567890x000x010x020x030x040x05 0x060x07 Distance Between Antennas (cm)RSSI Levels and Oscillator Status Register Value (0x0F)InitialRF October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 AFigure4.

10 LongSideRSSIL evelMeasurementFigure5. ShortSideRSSIL evelMeasurementFigure6. Top Collision11 SLOA227A October2015 RevisedDecember2016 SubmitDocumentationFeedbackCopyright 2015 2016,TexasInstrumentsIncorporatedNFC/HFR FIDR eader/WriterUsingthe TRF7970 AThe initialRF collisioncan be accomplishedby performingthe followingsteps:1. Writea 0x02or 0x03(3-V or 5-V operation)to the ChipStatusControlregister(0x00),disablin gthetransmitterand enablingthe Senda TestExternalRF directcommand(0x19).3. Delay50 s to allowthe transceiverto measurethe field strengthand latchthe valueinto the Readthe RSSIL evelsand OscillatorStatusregister(0x0F).5. If the activechannelRSSI value(bits 2-0) is greaterthan0, remainin targetmodefor a If the ActivechannelRSSI value(bits 2-0) is equalto 0, go into ini