HT45F4N datasheet(39/170 Pages) HOLTEK

39 / 170 page

Rev. 1.30

De�e��e� 1�� 01�

Rev. 1.30

De�e��e� 1�� 01�

HT45F4N/HT45FH4N

Power Bank Flash MCU

HT45F4N/HT45FH4N

Power Bank Flash MCU

Reading Data from the EEPROM

ToreaddatafromtheEEPROM,thereadenablebit,RDEN,intheEECregistermustfirstbeset

hightoenablethereadfunction.TheEEPROMaddressofthedatatobereadmustthenbeplaced

intheEEAregister.IftheRDbitintheEECregisterisnowsethigh,areadcyclewillbeinitiated.

SettingtheRDbithighwillnotinitiateareadoperationiftheRDENbithasnotbeenset.When

thereadcycleterminates,theRDbitwillbeautomaticallyclearedtozero,afterwhichthedatacan

bereadfromtheEEDregister.ThedatawillremainintheEEDregisteruntilanotherreadorwrite

operationisexecuted.TheapplicationprogramcanpolltheRDbittodeterminewhenthedatais

validforreading.

Writing Data to the EEPROM

TheEEPROMaddressofthedatatobewrittenmustfirstbeplacedintheEEAregisterandthedata

placedintheEEDregister.TowritedatatotheEEPROM,thewriteenablebit,WREN,intheEEC

registermustfirstbesethightoenablethewritefunction.Afterthis,theWRbitintheEECregister

mustbeimmediatelysethightoinitiateawritecycle.Thesetwoinstructionsmustbeexecuted

consecutively.TheglobalinterruptbitEMIshouldalsofirstbeclearedbeforeimplementingany

writeoperations,andthensetagainafterthewritecyclehasstarted.NotethatsettingtheWRbit

highwillnotinitiateawritecycleiftheWRENbithasnotbeenset.AstheEEPROMwritecycleis

controlledusinganinternaltimerwhoseoperationisasynchronoustomicrocontrollersystemclock,

acertaintimewillelapsebeforethedatawillhavebeenwrittenintotheEEPROM.Detectingwhen

thewritecyclehasfinishedcanbeimplementedeitherbypollingtheWRbitintheEECregisteror

byusingtheEEPROMinterrupt.Whenthewritecycleterminates,theWRbitwillbeautomatically

clearedtozerobythemicrocontroller,informingtheuserthatthedatahasbeenwrittentothe

EEPROM.TheapplicationprogramcanthereforepolltheWRbittodeterminewhenthewritecycle

hasended.

Write Protection

Protectionagainstinadvertentwriteoperationisprovidedinseveralways.Afterthedeviceis

powered-ontheWriteEnablebitinthecontrolregisterwillbeclearedpreventinganywrite

operations.Alsoatpower-ontheBankPointer,BP,willberesettozero,whichmeansthatData

MemoryBank0willbeselected.AstheEEPROMcontrolregisterislocatedinBank1,thisaddsa

furthermeasureofprotectionagainstspuriouswriteoperations.Duringnormalprogramoperation,

ensuringthattheWriteEnablebitinthecontrolregisterisclearedwillsafeguardagainstincorrect

writeoperations.

EEPROM Interrupt

TheEEPROMwriteinterruptisgeneratedwhenanEEPROMwritecyclehasended.TheEEPROM

interruptmustfirstbeenabledbysettingtheDEEbitintherelevantinterruptregister.Howeveras

theEEPROMiscontainedwithinaMulti-functionInterrupt,theassociatedmulti-functioninterrupt

enablebitmustalsobeset.WhenanEEPROMwritecycleends,theDEFrequestflagandits

associatedmulti-functioninterruptrequestflagwillbothbeset.Iftheglobal,EEPROMandMulti-

functioninterruptsareenabledandthestackisnotfull,ajumptotheassociatedMulti-function

Interruptvectorwilltakeplace.WhentheinterruptisservicedonlytheMulti-functioninterruptflag

willbeautomaticallyreset,theEEPROMinterruptflagmustbemanuallyresetbytheapplication

program.MoredetailscanbeobtainedintheInterruptsection.

HT45F4N Datasheet(PDF) 39 Page - Holtek Semiconductor Inc

HT45F4N Datasheet(HTML) 39 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