HT66F018 datasheet(49/154 Pages) HOLTEK

49 / 154 page

Rev. 1.70

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HT66F018

A/D Flash MCU with EEPROM

HT66F018

A/D Flash MCU with EEPROM

Entering the IDLE1 Mode

ThereisonlyonewayforthedevicetoentertheIDLE1Modeandthatistoexecutethe“HALT”

instructionintheapplicationprogramwiththeIDLENbitinSMODregisterequalto“1”andthe

FSYSONbitinCTRLregisterequalto“1”.Whenthisinstructionisexecutedundertheconditions

describedabove,thefollowingwilloccur:

• ThesystemclockandTimeBaseclockandfSUBclockwillbeonandtheapplicationprogramwill

stopatthe“HALT”instruction.

• TheDataMemorycontentsandregisterswillmaintaintheirpresentcondition.

• TheWDTwillbeclearedandresumecountingiftheWDTisenabled.

• TheI/Oportswillmaintaintheirpresentconditions.

• Inthestatusregister,thePowerDownflag,PDF,willbesetandtheWatchdogtime-outflag,TO,

willbecleared.

Standby Current Considerations

AsthemainreasonforenteringtheSLEEPorIDLEModeistokeepthecurrentconsumptionofthe

devicetoaslowavalueaspossible,perhapsonlyintheorderofseveralmicro-ampsexceptinthe

IDLE1Mode,thereareotherconsiderationswhichmustalsobetakenintoaccountbythecircuit

designerifthepowerconsumptionistobeminimised.SpecialattentionmustbemadetotheI/Opins

onthedevice.Allhigh-impedanceinputpinsmustbeconnectedtoeitherafixedhighorlowlevelas

anyfloatinginputpinscouldcreateinternaloscillationsandresultinincreasedcurrentconsumption.

Thisalsoappliestothedevicewhichhasdifferentpackagetypes,astheremaybeunbonbedpins.

Thesemusteitherbesetupasoutputsorifsetupasinputsmusthavepull-highresistorsconnected.

Caremustalsobetakenwiththeloads,whichareconnectedtoI/Opins,whicharesetupasoutputs.

Theseshouldbeplacedinaconditioninwhichminimumcurrentisdrawnorconnectedonlyto

externalcircuitsthatdonotdrawcurrent,suchasotherCMOSinputs.Alsonotethatadditional

standbycurrentwillalsoberequirediftheconfigurationoptionshaveenabledtheLXTorLIRC

oscillator.

IntheIDLE1Modethesystemoscillatorison,ifthesystemoscillatorisfromthehighspeed

systemoscillator,theadditionalstandbycurrentwillalsobeperhapsintheorderofseveralhundred

micro-amps.

HT66F018 Datasheet(PDF) 49 Page - Holtek Semiconductor Inc