User`s guide

Rev. 1.10 42 November 14, 2014 Rev. 1.10 43 November 14, 2014
HT66FW2230
Wireless Charger A/D Flash 8-Bit MCU
Watchdog Timer
TheWatchdogTimerisprovidedtopreventprogrammalfunctionsorsequencesfromjumpingto
unknownlocations,duetocertainuncontrollableexternaleventssuchaselectricalnoise.
Watchdog Timer Clock Source
TheWatchdogTimerclocksourceissourcedfromLIRCoscillators.TheLIRCinternaloscillator
hasanapproximatefrequencyof32kHzandthisspeciedinternalclockperiodcanvarywithV
DD
,
temperatureandprocessvariations.TheWatchdogTimersourceclockisthensubdividedbyaratio
of2
8
to2
18
togivelongertimeouts,theactualvaluebeingchosenusingtheWS2~WS0bitsinthe
WDTCregister.
Watchdog Timer Control Register
Asingleregister,WDTC,controlstherequiredtimeoutperiodaswellastheenableoperation.The
WDTCregisterisinitiatedto01010011Batanyreset(anyresetincludesPORreset,LVRreset,LVR
softwarereset,WDTtime-outinCPUoperatingandWDTsoftwarereset)butkeepsunchangedat
theWDTtime-outoccurrenceinapowerdownstate.
WDTC Register
Bit 7 6 5 4 3 2 1 0
Name WE4 WE3 WE2 WE1 WE0 WS2 WS1 WS0
R/W R/W R/W R/W R/W R/W R/W R/W R/W
POR 0 1 0 1 0 0 1 1
Bit7~3 WE4 ~ WE0:WDTfunctionsoftwarecontrol
10101or01010:Enabled
Othervalues:ResetMCU(resetwillbeactiveafter2~3LIRCclockfordebouncetime)
IftheMCUresetandit’scausedbyWE[4:0]inWDTCsoftwarereset,theWRFag
inRSTFCregisterwillbesetafterreset.
Bit2~0 WS2 ~ WS0:WDTTime-outperiodselection
000:2
8
/f
SUB
001:2
10
/f
SUB
010:2
12
/f
SUB
011:2
14
/f
SUB
(default)
100:2
15
/f
SUB
101:2
16
/f
SUB
110:2
17
/f
SUB
111:2
18
/f
SUB
ThesethreebitsdeterminethedivisionratiooftheWatchdogTimersourceclock,
whichinturndeterminesthetimeoutperiod.
RSTFC Register
Bit 7 6 5 4 3 2 1 0
Name — — — — ERSTF LVRF — WRF
R/W — — — — R/W R/W — R/W
POR — — — — 0 × — 0
Bit7~4 Unimplemented,readas“0”
Bit3 ERSTF:ResetcausedbyRST[7:0]setting
Describeelsewhere
Bit2 LVRF:LVRfunctionresetag
Describeelsewhere
Bit1 Unimplemented,readas“0”