HT68F003 datasheet(15/119 Pages) HOLTEK

15 / 119 page

Rev. 1.41

April 11, 2017

Rev. 1.41

April 11, 2017

HT68F002/HT68F0025/HT68F003

Cost-Effective Flash MCU with EEPROM

HT68F002/HT68F0025/HT68F003

Cost-Effective Flash MCU with EEPROM

Fe tc h In st . 1E xe cu te I ns t. 1

Fe tc h In st . 2

Fl us h Pi pel in e

DE LA Y:

MO V A, [1 2H ]

CA LL D EL AY

CP L [ 12H ]

NO P

Ex ec ut e In st . 2

Fe tc h In st . 3

Fe tc h In st . 6

Ex ec ut e In s t. 6

Fe tc h In st . 7

Instruction Fetching

Program Counter

Duringprogramexecution,theProgramCounterisusedtokeeptrackoftheaddressofthe

nextinstructiontobeexecuted.Itisautomaticallyincrementedbyoneeachtimeaninstruction

isexecutedexceptforinstructions,suchas"JMP"or"CALL"thatdemandajumptoanon-

consecutiveProgramMemoryaddress.Onlythelower8bits,knownastheProgramCounterLow

Whenexecutinginstructionsrequiringjumpstonon-consecutiveaddressessuchasajumpinstruction,

asubroutinecall,interruptorreset,etc.,themicrocontrollermanagesprogramcontrolbyloading

therequiredaddressintotheProgramCounter.Forconditionalskipinstructions,oncethecondition

hasbeenmet,thenextinstruction,whichhasalreadybeenfetchedduringthepresentinstruction

execution,isdiscardedandadummycycletakesitsplacewhilethecorrectinstructionisobtained.

Device

Program Counter

Program Counter High byte

PCL Register

HT68F002/HT68F003

PC9~PC8

PCL7~PCL0

HT68F0025

PC10~PC8

PCL7~PCL0

ThelowerbyteoftheProgramCounter,knownastheProgramCounterLowregisterorPCL,is

availableforprogramcontrolandisareadableandwriteableregister.Bytransferringdatadirectly

intothisregister,ashortprogramjumpcanbeexecuteddirectly,however,asonlythislowbyteis

availableformanipulation,thejumpsarelimitedtothepresentpageofmemory,thatis256locations.

Whensuchprogramjumpsareexecuteditshouldalsobenotedthatadummycyclewillbeinserted.

ManipulatingthePCLregistermaycauseprogrambranching,soanextracycleisneededtopre-fetch.

Stack

ThisisaspecialpartofthememorywhichisusedtosavethecontentsoftheProgramCounter

only.Thestackisneitherpartofthedatanorpartoftheprogramspace,andisneitherreadablenor

writeable.TheactivatedlevelisindexedbytheStackPointer,andisneitherreadablenorwriteable.

Atasubroutinecallorinterruptacknowledgesignal,thecontentsoftheProgramCounterarepushed

ontothestack.Attheendofasubroutineoraninterruptroutine,signaledbyareturninstruction,

RETorRETI,theProgramCounterisrestoredtoitspreviousvaluefromthestack.Afteradevice

reset,theStackPointerwillpointtothetopofthestack.

Ifthestackisfullandanenabledinterrupttakesplace,theinterruptrequestflagwillberecorded

buttheacknowledgesignalwillbeinhibited.WhentheStackPointerisdecremented,byRETor

RETI,theinterruptwillbeserviced.Thisfeaturepreventsstackoverflowallowingtheprogrammer

tousethestructuremoreeasily.However,whenthestackisfull,aCALLsubroutineinstructioncan

stillbeexecutedwhichwillresultinastackoverflow.Precautionsshouldbetakentoavoidsuch

caseswhichmightcauseunpredictableprogrambranching.Ifthestackisoverflow,thefirstProgram

Countersaveinthestackwillbelost.

HT68F003 Datasheet(PDF) 15 Page - Holtek Semiconductor Inc

HT68F003 Datasheet(HTML) 15 Page - Holtek Semiconductor Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL