Holtek BS82B12A-3 - Reset Initial Conditions

Rev. 1.20 60 January 23, 2015 Rev. 1.20 61 January 23, 2015
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
Watchdog Time-out Reset during SLEEP or IDLE Mode
TheWatchdogtime-outResetduringSLEEPorIDLEModeisalittledifferentfromotherkinds
ofreset.MostoftheconditionsremainunchangedexceptthattheProgramCounterandtheStack
PointerwillbeclearedtozeroandtheTOagwillbesethigh.RefertotheA.C.Characteristicsfor
t
SST
details.
 
 
    
Note:Thet
SST
is15~16clockcyclesifthesystemclocksourceisprovidedbytheHIRC.
Thet
SST
is1~2clockfortheLIRC.Thet
SST
is1024clockfortheLXT.
WDT Time-out Reset during SLEEP or IDLE Timing Chart
Reset Initial Conditions
Thedifferenttypesofresetdescribedaffecttheresetagsindifferentways.Theseags,known
asPDFandTOarelocatedinthestatusregisterandarecontrolledbyvariousmicrocontroller
operations,suchastheSLEEPorIDLEModefunctionorWatchdogTimer.Theresetflagsare
showninthetable:
TO PDF RESET Conditions
0 0
Power-on reset
u u LVR reset during NORMAL or SLOW Mode operation
1 u WDT time-out reset during NORMAL or SLOW Mode operation
1 1 WDT time-out reset during IDLE or SLEEP Mode operation
Note:"u"standsforunchanged
Thefollowingtableindicatesthewayinwhichthevariouscomponentsofthemicrocontrollerare
affectedafterapower-onresetoccurs.
Item Condition After RESET
Program Counter Reset to zero
Interrupts All interrupts will be disabled
WDT Clear after reset, WDT begins counting
Timer Modules Timer Modules will be turned off
Input/Output Ports I/O ports will be setup as inputs
Stack Pointer Stack Pointer will point to the top of the stack
Thedifferentkindsofresetsallaffecttheinternalregistersofthemicrocontrollerindifferentways.
Toensurereliablecontinuationofnormalprogramexecutionafteraresetoccurs,itisimportantto
knowwhatconditionthemicrocontrollerisinafteraparticularresetoccurs.Thefollowingtable
describeshoweachtypeofresetaffectseachofthemicrocontrollerinternalregisters.