전자부품 데이터시트 검색엔진 |
|
HT82B42R 데이터시트(PDF) 45 Page - Holtek Semiconductor Inc |
|
HT82B42R 데이터시트(HTML) 45 Page - Holtek Semiconductor Inc |
45 / 84 page Rev. 1.10 �� �ove��e� 0�� �01� Rev. 1.10 �� �ove��e� 0�� �01� HT82B42R/HT82B42RE I/O MCU with USB Interface Standby Current Considerations AsthemainreasonforenteringthePowerDownModeistokeepthecurrentconsumptionofthe microcontrollertoaslowavalueaspossible,perhapsonlyintheorderofseveralmicro-amps,there areotherconsiderationswhichmustalsobetakenintoaccountbythecircuitdesignerifthepower consumptionistobeminimised. SpecialattentionmustbemadetotheI/Opinsonthedevice.Allhigh-impedanceinputpinsmust beconnectedtoeitherafixedhighorlowlevelasanyfloatinginputpinscouldcreateinternal oscillationsandresultinincreasedcurrentconsumption.Caremustalsobetakenwiththeloads, whichareconnectedtoI/Opins,whicharesetupasoutputs.Theseshouldbeplacedinacondition inwhichminimumcurrentisdrawnorconnectedonlytoexternalcircuitsthatdonotdrawcurrent, suchasotherCMOSinputs. IftheconfigurationoptionshaveenabledtheWatchdogTimerinternaloscillatorthenthiswill continuetorunwheninthePowerDownModeandwillthusconsumesomepower.Forpower sensitiveapplicationsitmaybethereforepreferabletousethesystemclocksourcefortheWatchdog Timer. Wake-up AfterthesystementersthePowerDownMode,itcanbewokenupfromoneofvarioussources listedasfollows: • Anexternalreset • AnexternalfallingedgeWake-up • Asysteminterrupt • AWDToverflow Ifthesystemiswokenupbyanexternalreset,thedevicewillexperienceafullsystemreset, however,ifthedeviceiswokenupbyaWDToverflow,aWatchdogTimerresetwillbeinitiated. Althoughbothofthesewake-upmethodswillinitiatearesetoperation,theactualsourceofthe wake-upcanbedeterminedbyexaminingtheTOandPDFflags.ThePDFflagisclearedbya systempower-uporexecutingtheclearWatchdogTimerinstructionsandissetwhenexecutingthe "HALT"instruction.TheTOflagissetifaWDTtime-outoccurs,andcausesawake-upthatonly resetstheProgramCounterandStackPointer,theotherflagsremainintheiroriginalstatus. Eachpincanbesetupviaanindividualconfigurationoptiontopermitanegativetransitiononthe pintowake-upthesystem.Whenapinwake-upoccurs,theprogramwillresumeexecutionatthe instructionfollowingthe"HALT"instruction. Ifthesystemiswokenupbyaninterrupt,thentwopossiblesituationsmayoccur.Thefirstiswhere therelatedinterruptisdisabledortheinterruptisenabledbutthestackisfull,inwhichcasethe programwillresumeexecutionattheinstructionfollowingthe"HALT"instruction.Inthissituation, theinterruptwhichwoke-upthedevicewillnotbeimmediatelyserviced,butwillratherbeserviced laterwhentherelatedinterruptisfinallyenabledorwhenastacklevelbecomesfree.Theother situationiswheretherelatedinterruptisenabledandthestackisnotfull,inwhichcasetheregular interruptresponsetakesplace.Ifaninterruptrequestflagissetto"1"beforeenteringthePower DownMode,thewake-upfunctionoftherelatedinterruptwillbedisabled. Nomatterwhatthesourceofthewake-upeventis,onceawake-upsituationoccurs,atimeperiod equalto1024systemclockperiodswillberequiredbeforenormalsystemoperationresumes. However,ifthewake-uphasoriginatedduetoaninterrupt,theactualinterruptsubroutineexecution willbedelayedbyanadditionaloneormorecycles.Ifthewake-upresultsintheexecutionofthe nextinstructionfollowingthe"HALT"instruction,thiswillbeexecutedimmediatelyafterthe1024 systemclockperioddelayhasended. |
유사한 부품 번호 - HT82B42R_14 |
|
유사한 설명 - HT82B42R_14 |
|
|
링크 URL |
개인정보취급방침 |
ALLDATASHEET.CO.KR |
ALLDATASHEET 가 귀하에 도움이 되셨나요? [ DONATE ] |
Alldatasheet는? | 광고문의 | 운영자에게 연락하기 | 개인정보취급방침 | 링크교환 | 제조사별 검색 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |