HT45F2020 datasheet(21/85 Pages) HOLTEK

21 / 85 page

Rev. 1.00

April 11, 2017

Rev. 1.00

April 11, 2017

HT45F2020/HT45F2022

Sound Effect Generator Flash MCU

HT45F2020/HT45F2022

Sound Effect Generator Flash MCU

Accumulator – ACC

TheAccumulatoriscentraltotheoperationofanymicrocontrollerandiscloselyrelatedwith

operationscarriedoutbytheALU.TheAccumulatoristheplacewhereallintermediateresults

fromtheALUarestored.WithouttheAccumulatoritwouldbenecessarytowritetheresultof

eachcalculationorlogicaloperationsuchasaddition,subtraction,shift,etc.,totheDataMemory

resultinginhigherprogrammingandtimingoverheads.Datatransferoperationsusuallyinvolve

thetemporarystoragefunctionoftheAccumulator;forexample,whentransferringdatabetween

oneuser-definedregisterandanother,itisnecessarytodothisbypassingthedatathroughthe

Accumulatorasnodirecttransferbetweentworegistersispermitted.

Program Counter Low Register – PCL

Toprovideadditionalprogramcontrolfunctions,thelowbyteoftheProgramCounterismade

accessibletoprogrammersbylocatingitwithintheSpecialPurposeareaoftheDataMemory.By

manipulatingthisregister,directjumpstootherprogramlocationsareeasilyimplemented.Loading

avaluedirectlyintothisPCLregisterwillcauseajumptothespecifiedProgramMemorylocation,

however,astheregisterisonly8-bitwide,onlyjumpswithinthecurrentProgramMemorypageare

permitted.Whensuchoperationsareused,notethatadummycyclewillbeinserted.

Look-up Table Registers – TBLP, TBLH

Thesetwospecialfunctionregistersareusedtocontroloperationofthelook-uptablewhichis

storedintheProgramMemory.TBLPisthetablepointersandindicatethelocationwherethetable

dataislocated.Itsvaluemustbesetupbeforeanytablereadcommandsareexecuted.Itsvalue

canbechanged,forexampleusingthe“INC”or“DEC”instructions,allowingforeasytabledata

pointingandreading.TBLHisthelocationwherethehighorderbyteofthetabledataisstored

afteratablereaddatainstructionhasbeenexecuted.Notethatthelowerordertabledatabyteis

transferredtoauserdefinedlocation.

Status Register – STATUS

This8-bitregistercontainsthezeroflag(Z),carryflag(C),auxiliarycarryflag(AC),overflowflag

(OV),powerdownflag(PDF),andwatchdogtime-outflag(TO).Thesearithmetic/logicaloperation

andsystemmanagementflagsareusedtorecordthestatusandoperationofthemicrocontroller.

WiththeexceptionoftheTOandPDFflags,bitsinthestatusregistercanbealteredbyinstructions

likemostotherregisters.AnydatawrittenintothestatusregisterwillnotchangetheTOorPDFflag.

Inaddition,operationsrelatedtothestatusregistermaygivedifferentresultsduetothedifferent

instructionoperations.TheTOflagcanbeaffectedonlybyasystempower-up,aWDTtime-outor

byexecutingthe“CLRWDT”or“HALT”instruction.ThePDFflagisaffectedonlybyexecuting

the“HALT”or“CLRWDT”instructionorduringasystempower-up.

HT45F2020 数据表(PDF) 21 Page - Holtek Semiconductor Inc

HT45F2020 数据表(HTML) 21 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

数据表下载