HT45F56 datasheet(40/90 Pages) HOLTEK

40 / 90 page

Rev. 1.11

April 11, 2017

Rev. 1.11

April 11, 2017

HT45F56

Shock Detector Flash MCU

HT45F56

Shock Detector Flash MCU

Themaximumtimeoutperiodiswhenthe215divisionratioisselected.Asanexample,witha32

kHzLIRCoscillatorasitssourceclock,thiswillgiveamaximumwatchdogperiodofaround1

secondforthe215divisionratioandaminimumtimeoutof7.8msforthe28divisionration.

“

CLR WDT”Instruction

8-stage Divider

WDT Prescaler

WE4~WE0 bits

WDTC

Reset MCU

fSUB

fSUB/28

8-to-1 MUX

CLR

WS2~WS0

(fSUB/28 ~ fSUB/215)

WDT Time-out

(28/fSUB ~ 215/fSUB)

“

HALT”Instruction

RES pin reset

Watchdog Timer

Reset and Initialisation

Aresetfunctionisafundamentalpartofanymicrocontrollerensuringthatthedevicescanbeset

tosomepredeterminedconditionirrespectiveofoutsideparameters.Themostimportantreset

conditionisafterpowerisfirstappliedtothemicrocontroller.Inthiscase,internalcircuitrywill

ensurethatthemicrocontroller,afterashortdelay,willbeinawelldefinedstateandreadyto

executethefirstprograminstruction.Afterthispower-onreset,certainimportantinternalregisters

willbesettodefinedstatesbeforetheprogramcommences.OneoftheseregistersistheProgram

Counter,whichwillberesettozeroforcingthemicrocontrollertobeginprogramexecutionfromthe

lowestProgramMemoryaddress.

Inadditiontothepower-onreset,situationsmayarisewhereitisnecessarytoforcefullyapply

aresetconditionwhenthemicrocontrollerisrunning.Oneexampleofthisiswhereafterpower

hasbeenappliedandthemicrocontrollerisalreadyrunning,theRESlineisforcefullypulledlow.

Insuchacase,knownasanormaloperationreset,someofthemicrocontrollerregistersremain

unchangedallowingthemicrocontrollertoproceedwithnormaloperationaftertheresetlineis

allowedtoreturnhigh.

AnothertypeofresetiswhentheWatchdogTimeroverflowsandresetsthemicrocontroller.All

typesofresetoperationsresultindifferentregisterconditionsbeingsetup.Anotherresetexistsinthe

formofaLowVoltageReset,LVR,whereafullresetisimplementedinsituationswherethepower

supplyvoltagefallsbelowacertainthreshold.

Reset Functions

Therearefivewaysinwhichamicrocontrollerresetcanoccur,througheventsoccurringboth

internallyandexternally.

HT45F56 数据表(PDF) 40 Page - Holtek Semiconductor Inc

HT45F56 数据表(HTML) 40 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

数据表下载