HT45F3W datasheet(61/167 Pages) HOLTEK

61 / 167 page

Rev. 1.50

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HT45F3W

R-Type Blood Pressure Meter Flash MCU

HT45F3W

R-Type Blood Pressure Meter Flash MCU

Programming Considerations

TheHXTandLXToscillatorsbothusethesameSSTcounter.Forexample,ifthesystemiswoken

upfromtheSLEEP0ModeandboththeHXTandLXToscillatorsneedtostart-upfromanoffstate.

TheLXToscillatorusestheSSTcounterafterHXToscillatorhasfinisheditsSSTperiod.

• IfthedeviceiswokenupfromtheSLEEP0ModetotheNORMALMode,thehighspeedsystem

oscillatorneedsanSSTperiod.ThedevicewillexecutefirstinstructionafterHTOis“1”.Atthis

time,theLXToscillatormaynotbestabilityiffSUBisfromLXToscillator.Thesamesituation

occursinthepower-onstate.TheLXToscillatorisnotreadyyetwhenthefirstinstructionis

executed.

• IfthedeviceiswokenupfromtheSLEEP1ModetoNORMALMode,andthesystemclock

sourceisfromHXToscillatorandFSTENis“1”,thesystemclockcanbeswitchedtotheLXT

orLIRCoscillatorafterwakeup.

• Thereareperipheralfunctions,suchasWDT,TMs,SPI1andLCDdriver,forwhichthefSYS

isused.IfthesystemclocksourceisswitchedfromfHtofL,theclocksourcetotheperipheral

functionsmentionedabovewillchangeaccordingly.

• Theon/offconditionoffSUBandfSdependsuponwhethertheWDTisenabledordisabledasthe

WDTclocksourceisselectedfromfSUB.

HT45F3W Datasheet(PDF) 61 Page - Holtek Semiconductor Inc