HT45F4MA datasheet(49/145 Pages) HOLTEK

49 / 145 page

Rev. 1.20

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Rev. 1.20

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HT45F4MA/HT45FH4MA/HT45FH4MA-1

Power Bank Flash MCU

HT45F4MA/HT45FH4MA/HT45FH4MA-1

Power Bank Flash MCU

Low Voltage Reset – LVR

Themicrocontrollercontainsalowvoltageresetcircuitinordertomonitorthesupplyvoltageofthe

device.TheLVRfunctionisalwaysenabledwithaspecificLVRvoltage,VLVR.Ifthesupplyvoltage

ofthedevicedropstowithinarangeof0.9V~VLVRsuchasmightoccurwhenchangingthebattery,

theLVRwillautomaticallyresetthedeviceinternallyandtheLVRFbitintheCTRLregisterwill

alsobesetto1.ForavalidLVRsignal,alowsupplyvoltage,i.e.,avoltageintherangebetween

0.9V~VLVRmustexistforatimegreaterthanthatspecifiedbytLVRintheA.C.characteristics.Ifthe

lowsupplyvoltagestatedoesnotexceedthisvalue,theLVRwillignorethelowsupplyvoltage

andwillnotperformaresetfunction.TheactualVLVRisfixedatavoltagevalueof2.55Vbythe

LVSbitsintheLVRCregister.IftheLVS7~LVS0bitsarechangedtosomecertainvaluesbythe

environmentalnoise,theLVRwillresetthedeviceafter2~3LIRCclockcycles.Whenthishappens,

theLRFbitintheCTRLregisterwillbesetto1.Afterpowerontheregisterwillhavethevalueof

01010101B.NotethattheLVRfunctionwillbeautomaticallydisabledwhenthedeviceentersthe

powerdownmode.

LV R

In te r nal R es et

t RS TD + t SST

Note:tRSTDispower-ondelay,typicaltime=50ms

Low Voltage Reset Timing Chart

• LVRC Register

Bit

Na�e

LVS7

LVS�

LVS5

LVS�

LVS3

LVS2

LVS1

LVS0

R/W

POR

Bit7~0

LVS7~LVS0:LVRvoltageselect

01010101:2.55V

00110011:2.55V

10011001:2.55V

10101010:2.55V

Anyothervalue:GeneratesMCUreset–registerisresettoPORvalue

Whenanactuallowvoltageconditionoccurs,asspecifiedbytheabovedefinedLVR

voltagevalue,anMCUresetwillbegenerated.Theresetoperationwillbeactivated

after2~3LIRCclockcycles.Inthissituationthisregistercontentswillremainthe

sameaftersucharesetoccurs.

Anyregistervalue,otherthanthefourdefinedvaluesabove,willalsoresultinthe

generationofanMCUreset.Theresetoperationwillbeactivatedafter2~3LIRCclock

cycles.HoweverinthissituationthisregistercontentswillberesettothePORvalue.

HT45F4MA 数据表(PDF) 49 Page - Holtek Semiconductor Inc

HT45F4MA 数据表(HTML) 49 Page - Holtek Semiconductor Inc

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