Holtek BS82B12A-3 - S�Stem Ope�Ation Modes

Rev. 1.20 50 January 23, 2015 Rev. 1.20 51 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
System Operation Modes
Therearefivedifferentmodesofoperationforthemicrocontroller,eachonewithitsown
specialcharacteristicsandwhichcanbechosenaccordingtothespecificperformanceand
powerrequirementsoftheapplication.Therearetwomodesallowingnormaloperationofthe
microcontroller,theNORMALModeandSLOWMode.Theremainingthreemodes,theSLEEP,
IDLE0andIDLE1ModeareusedwhenthemicrocontrollerCPUisswitchedofftoconservepower.
Operating
Mode
Description
CPU f
SYS
f
SUB
NORMAL mode On f
H
~f
H
/64 On
SLOW mode On f
SUB
On
ILDE0 mode Off Off On
IDLE1 mode Off On On
SLEEP mode Off Off Off
NORMAL Mode
Asthenamesuggeststhisisoneofthemainoperatingmodeswherethemicrocontrollerhasallof
itsfunctionsoperationalandwherethesystemclockisprovidedbythehighspeedoscillator.This
modeoperatesallowingthemicrocontrollertooperatenormallywithaclocksourcewillcomefrom
thehighspeedoscillator,HIRC.Thehighspeedoscillatorwillhoweverrstbedividedbyaratio
rangingfrom1to64,theactualratiobeingselectedbytheCKS2~CKS0andHLCLKbitsinthe
SMODregister.Althoughahighspeedoscillatorisused,runningthemicrocontrolleratadivided
clockratioreducestheoperatingcurrent.
SLOW Mode
Thisisalsoamodewherethemicrocontrolleroperatesnormallyalthoughnowwithaslowerspeed
clocksource.Theclocksourceusedwillbefromf
SUB
.Runningthemicrocontrollerinthismode
allowsittorunwithmuchloweroperatingcurrents.IntheSLOWMode,thef
H
isoff.
SLEEP Mode
TheSLEEPModeisenteredwhenanHALTinstructionisexecutedandwhentheIDLENbitin
theSMODregisterislow.IntheSLEEPmodetheCPUwillbestopped,andthef
SUB
clockwillbe
stoppedtoo,theWatchdogTimerfunctionisautomaticallydisabledbyhardwareforpowersaving.
IDLE0 Mode
TheIDLE0ModeisenteredwhenaHALTinstructionisexecutedandwhentheIDLENbitinthe
SMODregisterishighandtheFSYSONbitintheCTRLregisterislow.IntheIDLE0Modethe
systemoscillatorwillbestopandwillthereforebeinhibitedfromdrivingtheCPU.
IDLE1 Mode
TheIDLE1ModeisenteredwhenaHALTinstructionisexecutedandwhentheIDLENbitin
theSMODregisterishighandtheFSYSONbitintheCTRLregisterishigh.IntheIDLE1Mode
thesystemoscillatorwillbeinhibitedfromdrivingtheCPUbutmaycontinuetoprovideaclock
sourcetokeepsomeperipheralfunctionsoperational.IntheIDLE1Mode,thesystemoscillatorwill
continuetorun,andthissystemoscillatormaybethehighspeedorlowspeedsystemoscillator.