HT45F39 datasheet(68/102 Pages) HOLTEK

68 / 102 page

Rev. 1.10

July 01, 2016

Rev. 1.10

July 01, 2016

HT45F39/HT45F391

Ultrasonic Distance Measurement 8-bit Flash MCU

HT45F39/HT45F391

Ultrasonic Distance Measurement 8-bit Flash MCU

Auto-Envelope Processing Operation

TheAuto-EnvelopeProcessingUnitinputsignalissourcedfromtheADCoutput.

Thefollowingpointsshouldbenoted:

• IftheSUMvalueisover8bits,thentheSUMvaluewillbesetto0xffautomatically.

• TheworkingFIFOhas10levels,locatedinthe18-levelFIFO.When10bytesintheFIFOhave

beenreadorwrittenaninterruptwillbegenerated.

Therearetwooperatingmodes,selectedbytheAEVMODbitintheAVPCTRLregister.

AVEMOD=0 – Mode0

• ThecompareddataisdeterminedbythedataintheSUMCMPregister.Thereisonlyonecompare

datainmode0.

• Thedata,namelySUM,willbeinputintothe10LevelFIFOdirectly.Whenthe10-LevelFIFOinterrupt

isenabledandthe10thdataisreceived,itwillgenerateaninterrupt.Notethattheusershouldfetchthe

receiveddatawithinatimeof40instructioncyclestopreventdatafromgoingmissing.

ThedesignercansetupvariousvaluesintheSUMCMPregistertoformvariousthresholdvoltage

levels.Inthisway,thedesignercanimplementanautomaticthresholdadaptationfunction.Usually,

thismodeisusedtodetectUltrasonicsensorechosandtocalculatethedistanceforlongdistance

measurements.

AVEMOD=1 – Mode1

• Thismodeisusedtocomparetheinputdataandcompareitwiththedatainthe10-levelFIFOat

a800KHzclockrate.Theusercanenter10setsofthecomparisondataintothe10-levelFIFO.

WhentheAEPisenabledbytheAVPbit,thesystemhardwarewillautomaticallyfetchthedata

fromtheFIFOtocomparewiththeinputsignalata800KHzclockrate.When10setsofdata

havebeenfetchedfromtheFIFO,thesystemwillgenerateaninterruptandtheusershouldthen

enteranother10setsofdatatotheFIFOwithinatimeof40instructionscycles.

Atthebeginning,thedesignercanusetheAEPunittorecordtheUltrasonicsensorvibration

waveformdatausingtheIAPfunction.Therecordedwaveformdatacanbeusedasreferencedata

forcomparisonwiththeinputsignaltodetecttheEchointheSensorVibrationrangetoimplement

theshortrangefunctioninthismode.

Thecomparedresultscanbedeterminedbytheoptions.Whenthecompareddataislessthanthe

SUMdata,thecompareoutputis"1",andwhenthecomparrddataisgreaterthantheSUMdata,the

compareoutputis"0".Thecomparedoutputresultcanbeusedasthesourcetogenerateaninterrupt,

ENVCMPINT.ThetriggeredgecanbeselectedbytheENVEDGE1andENVEDGE0bitsinthe

ENVCMPregister.

Auto Envelop Process Unit Register Description

TheAutoEnvelopProcessUnit,namelyAEP,isimplementedinhardware.Theoveralloperation

oftheAEPunitiscontrolledusingnineregisters.TheDVCMregister,theADCconverteddataof

theVCM,isusedtoprovidetheinputsignalfortheRectifiertoimplementthefullwaverectified

function.TheSUMCMPregisterisusedtosetuptheComparatorValuefortheComparator

inputdata.TheENVCMPregisterisusedtosetuptheADCsamplingphaseadjustmentandthe

ComparatorInterruptEnableconditions.TheAVPCTRLregisteristhecontrolregisterfortheAEP

unit.Thesetworegisters,FIFOOUTandFIFOIN,areassignedfortheFIFOinputandoutputdata

andwriteFIFOaddress.TheFIFOCTRLregisteristheFIFOcontrolregisterwhichcontrolsthe

operationandindicatesthestatusoftheFIFO.

HT45F39 Datasheet(PDF) 68 Page - Holtek Semiconductor Inc

HT45F39 Datasheet(HTML) 68 Page - Holtek Semiconductor Inc

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