RS-485 Half-Duplex EVM User's Guide (Rev. B)

1 User's GuideSLLU173B October2012 RevisedJune2013RS-485 half -DuplexEvaluationModuleThismanualdes cribestheRS-485 half -DuplexEvaluationModule(EVM).ThisEVM helpsdesignersevaluatethedeviceperforman ce,supportingthefastdevelopmentandanalys isofdatatransmissionsystemsusinganyofthe TIRS-485half-duplexdevicesin :LeftasReceiverEVM, October2012 RevisedJune2013RS-485 half -DuplexEvaluationModuleSubmitDocumen tationFeedbackCopyright 2012 2013,TexasInstrumentsIncorporatedRTRTABD DERREDRVccRFSRFSABDDERREPOLCORDRABDDERPO LCORDRREABDDERPOLCORDRREM asterSN65 HVD82 SlaveSN65 HVD888 SlaveSN65 HVD888 SlaveSN65 HVD888 Cross-wirefault 0 the8-pinSOIC packagehaverobustdriversandreceiversin a , differentialdriveranda differentialreceiver,whichoperatefroma busportsuitableforhalf- duplex (two-wirebu s)communication,andallfeaturea ' :ThisEVMcomeswithouta ,8-pinSOICRS-485transceiverandsolderit (SeeFigure1).

2 TheSN65 HVD888transceivercorrectsa wrongbussignalpolaritycausedbya : a failsafebiasingnetworkmustbeimplemented( atthemasternode)tosetlogicreferenceandde finethesignalpolarityofthebus, a slavenodemusthaveitsreceiverenabledandit sdriverdisabled(RE= DE= Low), thebusmustbeidlingforthefailsafetime, ,thepolaritycorrectionis completeandis appliedtoboth, :Datastreamsofconsecutive0 s or1 s withdurationsexceedingtFS-mincanaccident lytriggera October2012 RevisedJune2013 SubmitDocumentationFeedbackCopyright 2012 2013,TexasInstrumentsIncorporatedNOTE: R2, R3, R4 - DNIA_2B_2 DEDB/RER_1 RADUT_VCCEARTH_GNDDUT_GNDDUT_GNDEARTH_GN DDUT_GNDEARTH_GNDEARTH_GNDEARTH_GNDEARTH _GNDDUT_GNDDUT_VCCDUT_GNDDUT_GNDEARTH_GN DDUT_GNDEARTH_GNDDUT_GNDEARTH_GNDDUT_VCC DUT_VCCDUT_VCCDUT_VCCVCM_BVCM_ADUT_GNDEA RTH_GNDDUT_VCCVCM_BDUT_GNDEARTH_GNDEARTH _GNDDUT_GNDEARTH_GNDDUT_VCCVCM_ADUT_GNDV CM_AVCM_BEARTH_GNDEARTH_GNDEARTH_GNDEART H_GNDEARTH_GNDEARTH_GNDEARTH_GNDEARTH_GN DDUT_GNDDUT_GNDDUT_VCCDUT_GNDDUT_GNDDUT_ GNDDUT_GNDDUT_GNDR7 UNINSTALLEDTB23 PIN_TERMINAL_BLOCK123R250 OhmsR350 OhmsD3 RED LED Diode12D2 GREEN LED Diode12R450 OhmsC11uFR5120 OhmJMP9 Header 4x11234U1SN65 HVD7xR1/RE2DE3D4 GND5A6B7 VCC8R111k 3x1123 JMP14 Header 3x1123 JMP4 Header 4x11234C41uFC9 UNINSTALLEDJMP10 Header 4x11234 JMP8 Header 4x11234 JMP3 Header 4x11234R6 UNINSTALLEDC7

3 UNINSTALLEDD1 BLUE LED OhmsJMP7 Header 4x11234R11k OhmsJMP13 Header 3x1123 JMP1 Header 4x11234 JMP6 Header 4x11234TB13 PIN_TERMINAL_BLOCK123 JMP11 Header 3x1123R90 OhmC8 UNINSTALLEDR80 OhmR100 (JMP5is omitted) :Theexamplesin thisdocumentshowa ,theusermayneedtoprovidea 5-Vsignalgeneratorinputand5-Vpowersupply . Pin1 (EARTH)is a secondgroundpinthatallowsapplyinganexter nalvoltagebetweenGNDandEARTH tosimulatecommon-modevoltageconditions. Pin2 (GND)is alsoconnectstovariousjumpersontheboard. Pin3 (VCC)is connectedtothepositiveoutputofa regulatedpowersupplyunit(PSU)asit October2012 RevisedJune2013RS-485 half -DuplexEvaluationModuleSubmitDocumen tationFeedbackCopyright 2012 2013, Ch2 JMP41234 VCC123 JMP14D - ,ignorethecommon-modesimulationandconnec tEARTHtoGNDthroughawire-bridgebetweenpin 1 andpin2 ,orheadersthroughwhichthecontrolanddatas ignalsfortheRS485 half -DuplexEVMareapplied,JMP1,andJMP11to JMP14areprobepoints, resistors,R2,R3,andR4, , indicatingthatthesecomponentsarenotassem bled.

4 Becausesignalgeneratorshavea typicalsourceimpedanceof50 , theiroutputsignalistwicetherequiredsigna lvoltage,andassumesthattheon-board50- ;however,thisvoltagedivideractionis notaccomplished, givesanexampleforenteringa adjustedtomatchthedeviceVCCpowersupplyre quirements. Thegenerator sgroundterminalis connectedwithpin3,andthesignaloutputterm inalwithpin2 measuredthroughanoscilloscopewithitssign alinputconnectedtopin1 anditsgroundwireconnectedtopin2 ,mustnotreceivea ,it representsthereceiveroutput,R, , ,forproperoperation,it mustbeassuredthatthehigh-levelinputvolta geVIH 2 V andthelow-levelinputvoltageVIL October2012 RevisedJune2013 SubmitDocumentationFeedbackCopyright 2012 2013, maximumoutputsignallevel,basedontheVCCre quirementsofyourselectedRS-485device, ofTB1andobservetheblueLED(D1) ,R,willturnontheredLED(D3),andlogichigha tthedriverinput,D,turnsonthegreenLED(D2) .

5 If D is leftopen,aninternal100-k ,duetothesmallinputcurrent, , ,thereceiverenablepin(RE)mustbeatlogiclo wpotentialandthedriverenablepin(DE) (VOD= VA VB)onthebuswires,A ,it is possibletosensethedatatrafficin ,PSU-ground,throughthewire-bridgefrompin 1 topin2 attheterminalblock,TB1,whilepin3 (VCC),in thisexample,is power-supplyunit(PSU).5 SLLU173B October2012 RevisedJune2013RS-485 half -DuplexEvaluationModuleSubmitDocumen tationFeedbackCopyright 2012 2013, -7V to +12 VScopeCh1 Ch2 Ch3 providedbythewire-bridgefrompin2 topin3 atJMP2,andthehighpotentialforDEthrougha wire-bridgefrompin2 topin1 andpin3 measuredviachannel1,whichis connectedtopin1andpin2 measuresthereceivedataatJMP11,andchannel s3 and4 thebusvoltages,VAandVB, ( RS-485 )specifiesthreemaximumloadparamet ers:a maximumdifferentialloadof60 , amaximumcommon-modeloadof375 foreachbuswire,anda receivercommon-modevoltagerangefrom 7 V to+ reflectstheserequirementsthroughR5,R8,R9 ,andVCM.

6 Thepreviousexample,thefollowingboardchan gesneedtobeimplementedtoreflectmaximumlo adconditions:6RS-485 half -DuplexEvaluationModuleSLLU173B October2012 RevisedJune2013 SubmitDocumentationFeedbackCopyright 2012 2013, Ch3 Ch2 Ch1 BAPSU2 SignalGeneratorJMP412 VCC34 DJMP312 VCC34 JMP212 VCC34 Ch3 Ch2 replaceR5(120- default)with60 replaceR8andR9(0- default)with375 connectpin2 ofJMP7withpin1 andpin3 withpin4 replacethepreviouswire-bridgeatTB1witha secondpowersupplyunit(PSU2)andconnectthe groundterminalsofboth,PSU1andPSU2witha wire-bridge,asshownin , connectthegroundterminalofPSU2withpin1 ofTB1(EARTH), :LeftasReceiverEVM,RightasTransmitterEVM 7 SLLU173B October2012 RevisedJune2013RS-485 half -DuplexEvaluationModuleSubmitDocumen tationFeedbackCopyright 2012 2013, October2012 RevisedJune2013 SubmitDocumentationFeedbackCopyright 2012 2013,TexasInstrumentsIncorporatedEVALUAT IONBOARD/KIT/MODULE(EVM)ADDITIONALTERMST exasInstruments(TI)providestheenclosedEv aluationBoard/Kit/Module(EVM)

7 , theUser s Guide ,theboard/kitmaybereturnedwithin30d aysfromthedateofdeliveryfora ,EXPRESSED,IMPLIED,ORSTATUTORY, ,NEITHERPARTYSHALLBELIABLETOTHEOTHERFORA NYINDIRECT,SPECIAL,INCIDENTAL, 's Guideand,specifically,theWarningsandRest rictionsnoticein theUser's 's environmentaland/orsafetyprograms, grantedunderanypatentrightorotherintelle ctualpropertyrightofTIcoveringorrelating toanymachine,process,orcombinationin varietyofcustomersforproducts,andtherefo reourarrangementwiththeuseris ,customerproductdesign,softwareperforman ce, theEVMUser s Guideand/orEVMitself,thisEVMand/oraccomp anyinghardwaremayormaynotbesubjecttotheF ederalCommunicationsCommission(FCC)andIn dustryCanada(IC) ,thisevaluationboard/kit/moduleis intendedforuseforENGINEERINGDEVELOPMENT, DEMONSTRATIONOREVALUATIONPURPOSESONLY andis notconsideredbyTItobea finishedendproductfit generates,uses,andcanradiateradiofrequen cyenergyandhasnotbeentestedforcompliance withthelimitsofcomputingdevicespursuantt opart15ofFCCorICES-003rules, ,in radioUserPower/FrequencyUseObligations: Thisradiois intendedfordevelopment/professionaluseon lyin (s) is theuser s soleresponsibilitytoonlyoperatethisradio in ,whichis subjecttothefollowingtwoconditions.

8 (1)Thisdevicemaynotcauseharmfulinterfere nce,and(2)thisdevicemustacceptanyinterfe rencereceived, 's EVMdevicesThisequipmenthasbeentestedandf oundtocomplywiththelimitsfora ClassA digitaldevice, operatedin a ,uses,andcanradiateradiofrequencyenergya nd,if notinstalledandusedin accordancewiththeinstructionmanual, a residentialareais likelytocauseharmfulinterferencein EVMdevicesThisequipmenthasbeentestedandf oundtocomplywiththelimitsfora ClassB digitaldevice, a ,usesandcanradiateradiofrequencyenergyan d,if notinstalledandusedin accordancewiththeinstructions, ,thereis noguaranteethatinterferencewillnotoccuri n a ,whichcanbedeterminedbyturningtheequipme ntoffandon,theuseris encouragedtotrytocorrecttheinterferenceb yoneormoreofthefollowingmeasures: Reorientorrelocatethereceivingantenna.

9 Increasetheseparationbetweentheequipment andreceiver. Connecttheequipmentintoanoutletona circuitdifferentfromthattowhichthereceiv eris connected. INDUSTRYCANADAC ompliantThisClassA orB s (s).Operationis subjecttothefollowingtwoconditions:(1)th isdevicemaynotcauseinterference,and(2)th isdevicemustacceptanyinterference, ,thisradiotransmittermayonlyoperateusing anantennaofa typeandmaximum(orlesser) ,theantennatypeanditsgainshouldbesochose nthattheequivalentisotropicallyradiatedp ower( )is thislist,havinga gaingreaterthanthemaximumgainindicatedfo rthattype, riquedela classeA ouB estconforme la mentapprouv s parla partieresponsabledela conformit ontpuviderl autorit del'utilisateurpouractionnerl' sentappareilestconformeauxCNRd' 'exploitationestautoris e auxdeuxconditionssuivantes.

10 (1)l'appareilnedoitpasproduiredebrouilla ge,et(2)l'utilisateurdel'appareildoitacc eptertoutbrouillageradio lectriquesubi,m mesi le brouillageestsusceptibled'encompromettre le tachablesConform ment la r glementationd'IndustrieCanada,le pr sent metteurradiopeutfonctionneravecuneantenn ed'untypeetd'ungainmaximal(ouinf rieur)approuv pourl' butder duirelesrisquesdebrouillageradio lectrique l'intentiondesautresutilisateurs,il fautchoisirle typed'antenneetsongaindesortequela puissanceisotroperayonn e quivalente( )ned passepasl'intensit n cessaire l' tablissementd' sent metteurradioa t approuv parIndustrieCanadapourfonctionneravecles typesd'antenne num r s dansle manueld usageetayantungainadmissiblemaximaletl'i mp dancerequisepourchaquetyped' 'antennenoninclusdanscetteliste,oudontle gainestsup rieuraugainmaximalindiqu , sontstrictementinterditspourl'exploitati ondel' ImportantNoticeforUsersofthisProductinJa pan ThisdevelopmentkitisNOTcertifiedasConfir mingtoTechnicalRegulationsofRadioLawofJa panIf youusethisproductin Japan, a shieldedroomoranyothertestfacilityasdefi nedin thenotification#173issuedbyMinistryofInt ernalAffairsandCommunicationsonMarch28,2 006, oftheMinistry s RuleforEnforcementofRadioLawofJapan, RadioLawofJapanwithrespecttothisproduct.