HT69F360 datasheet(76/235 Pages) HOLTEK

76 / 235 page

Rev. 1.30

7�

�ove��e� 1�� 01�

Rev. 1.30

�ove��e� 1�� 01�

HT69F340/HT69F350/HT69F360

TinyPowerTM I/O Flash MCU with LCD & EEPROM

HT69F340/HT69F350/HT69F360

TinyPowerTM I/O Flash MCU with LCD & EEPROM

ThereisonlyonemethodofusingsoftwareinstructiontocleartheWatchdogTimer.Thatistouse

thesingle“CLRWDT”instructiontocleartheWDT.

Themaximumtime-outperiodiswhenthe218divisionratioisselected.Asanexample,witha

32kHzLIRCoscillatorasitssourceclock,thiswillgiveamaximumwatchdogperiodofaround8

secondsforthe218divisionratio,andaminimumtimeoutof7.8msforthe28divisionration.

ʺCLR WDTʺ instruction

8-stage Divider

WDT Prescaler

WE4~WE0 bits

WDTC Register

Reset MCU

LXT

fSUB

fS/28

8-to-1 MUX

CLR

WS2~WS0

(fS/28 ~ fS/218)

WDT Time-out

(28/fS ~ 218/fS)

LIRC

FSS bit

ʺHALTʺ instruction

RES pin reset

Watchdog Timer

Reset and Initialisation

Aresetfunctionisafundamentalpartofanymicrocontrollerensuringthatthedevicecanbeset

tosomepredeterminedconditionirrespectiveofoutsideparameters.Themostimportantreset

conditionisafterpowerisfirstappliedtothemicrocontroller.Inthiscase,internalcircuitrywill

ensurethatthemicrocontroller,afterashortdelay,willbeinawelldefinedstateandreadyto

executethefirstprograminstruction.Afterthispower-onreset,certainimportantinternalregisters

willbesettodefinedstatesbeforetheprogramcommences.OneoftheseregistersistheProgram

Counter,whichwillberesettozeroforcingthemicrocontrollertobeginprogramexecutionfromthe

lowestProgramMemoryaddress.

Inadditiontothepower-onreset,situationsmayarisewhereitisnecessarytoforcefullyapplya

resetconditionwhenthemicrocontrollerisrunning.Oneexampleofthisiswhereafterpowerhas

beenappliedandthemicrocontrollerisalreadyrunning,theRESlineisforcefullypulledlow.In

suchacase,knownasanormaloperationreset,someoftheregistersremainunchangedallowing

themicrocontrollertoproceedwithnormaloperationaftertheresetlineisallowedtoreturnhigh.

AnothertypeofresetiswhentheWatchdogTimeroverflowsandresetsthemicrocontroller.All

typesofresetoperationsresultindifferentregisterconditionsbeingsetup.Anotherresetexistsin

theformofaLowVoltageReset,LVR,whereafullreset,similartotheRESresetisimplementedin

situationswherethepowersupplyvoltagefallsbelowacertainthreshold.

Reset Functions

Thereareseveralwaysinwhichamicrocontrollerresetcanoccur,througheventsoccurringboth

internallyandexternally:

Power-on Reset

Themostfundamentalandunavoidableresetistheonethatoccursafterpowerisfirstappliedto

themicrocontroller.AswellasensuringthattheProgramMemorybeginsexecutionfromthefirst

memoryaddress,apower-onresetalsoensuresthatcertainotherregistersarepresettoknown

conditions.AlltheI/Oportandportcontrolregisterswillpowerupinahighconditionensuringthat

allpinswillbefirstsettoinputs.

HT69F360 データシート(PDF) 76 Page - Holtek Semiconductor Inc

HT69F360 データシート(HTML) 76 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

データシートダウンロード