HT45F75 datasheet(108/190 Pages) HOLTEK

108 / 190 page

Rev. 1.10

108

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Rev. 1.10

109

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HT45F75

Body Fat Scale Flash MCU

HT45F75

Body Fat Scale Flash MCU

Summary of A/D Conversion Steps

ThefollowingsummarisestheindividualstepsthatshouldbeexecutedinordertoimplementanA/D

conversionprocess.

• Step1

EnablepowerLDO,VCMforPGAandADC.

• Step2

SelectPGA,ADCandVREFgainbyPGAC0register.

• Step3

SelectPGAsettingforinputpinsconnectionandVCMoptionbyPGAC1register.

• Step4

Select the requiredA/D conversion clock 4.8MHz by correctly programming bits

ADCK4~ADCK0intheADCSregister.

• Step5

Selectoutputdatarate.

• Step6

SelectwhichchannelistobeconnectedtotheinternalPGAbycorrectlyprogrammingthe

CHSP2~CHSP0andCHSN2~CHSN0bitswhicharealsocontainedinthePGACSregister.

• Step7

ReleasepowerdownmodeandsleepmodebyADOFFandADSLPbitsinADCR0register.

• Step8

ResettheA/DbysettingtheADRSTtohighintheADCR0registerandclearingthisbittozero

toreleaseresetstatus.

• Step9

Iftheinterruptsaretobeused,theinterruptcontrolregistersmustbecorrectlyconfiguredto

ensuretheA/Dconverterinterruptfunctionisactive.Themasterinterruptcontrolbit,EMI,and

theA/Dconverterinterruptbit,ADE,mustbothbesethightodothis.

• Step10

Tocheckwhentheanalogtodigitalconversionprocessiscomplete,theEOCbitintheADCR1

registercanbepolled.Theconversionprocessiscompletewhenthisbitgoeslow.Whenthis

occurstheA/DdataregistersADRL,ADRMandADRHcanbereadtoobtaintheconversion

value.Asanalternativemethod,iftheinterruptsareenabledandthestackisnotfull,theprogram

canwaitforanA/Dinterrupttooccur.

Note:Whencheckingfortheendoftheconversionprocess,ifthemethodofpollingtheEOCbitin

theADCR1registerisused,theinterruptenablestepabovecanbeomitted.

Programming Considerations

DuringmicrocontrolleroperationswheretheA/Dconverterisnotbeingused,theA/Dinternal

circuitrycanbeswitchedofftoreducepowerconsumption,bysettingbitADOFFhighinthe

ADCR0register.Whenthishappens,theinternalA/Dconvertercircuitswillnotconsumepower

irrespectiveofwhatanalogvoltageisappliedtotheirinputlines.

HT45F75 Datasheet(PDF) 108 Page - Holtek Semiconductor Inc

HT45F75 Datasheet(HTML) 108 Page - Holtek Semiconductor Inc

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