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HT45F2002

2-Wire Communication Flash MCU

HT45F2002

2-Wire Communication Flash MCU

Multi-chip Hardware Considerations

Asthesingle-package-multi-chipdeviceiscomposedofanindividualMCUandthepowerlinedata

transceiverchip,usingthemtogetherrequirestheusertotakecareofsomespecialpoints.

Absolute Maximum Rating

TheAbsoluteMaximumRatingsforthetwoindividualchipsmustbecheckedfordiscrepanciesand

thenecessarycaretakenindevicehandlingandusage.

Power Supply and Consumption

ExaminationoftheblockdiagramwillrevealthatthepowerlinedatatransceiverchipGroundpin,

VSS,hasinternalconnectiontotheMCUGroundpin,VSS.Forthisreasonthesetwopinsdonot

needtobeconnectedexternally.Thesingle-package-multi-chipdeviceLDOpinisthepowerline

datatransceiverchipLDOoutputpin,VDD,whilethesingle-package-multi-chipdeviceVDDpinis

theMCUpowersupplyVDDpin.

Tocalculatethepowerconsumptionforthedevice,thetotaloperatingcurrentisthesumofthe

operatingcurrentfortheMCUspecifiedintheMCUdatasheetandtheoperatingcurrentforthe

powerlinedatatransceiverchiplistedinitsdatasheet.Similarly,thestandbycurrentisthesumof

thetwoindividualchipstandbycurrents.

Power Down and Wake up

TheMCUpower-downandwake-upfunctionsarecoveredintherelevantMCUdatasheet.However,

thepowerlinedatatransceiverchipisalwaysoperatingafterapower-up.Therefore,nopower-down

issueforthepowerlinedatatransceiverchipiscontrolledbytherelevantMCUdevice.

Unbonded MCU Pins

ExaminationoftherelevantMCUdatasheetwillrevealthatnotalloftheMCUI/Oportlinesare

bondedouttoexternalpins.Asaresultspecialattentionregardinginitialisationproceduresshould

bepaidtotheseportlines.Usersshouldensurethatthesepinsaresetupininputstateswithpullhigh

resistorsorinoutputstateswitheitherahighorlowlevelstoavoidadditionalpowerconsumption

resultingfromfloatinginputpins.

Multi-chip Programming Considerations

Tousethepowerlinedatatransceiverfunction,severalimportantstepsmustbeimplementedto

ensurethatthepowerlinedatatransceiverchipoperatesnormally:

TheMCUpowerline,VSS,isinternallyconnectedtothepowerlinedatatransceiverVSSpin.For

thisreason,thesetwopinsnoneedtobeconnectedexternally.

OthercorrespondingprogrammingconsiderationsmaybecoveredintheMCUandpowerlinedata

transceiverdatasheetsrespectively.Refertoallinformationintheindividualdatasheetfordesired

applications.