BS83A04A-3/BS83A04A-4
8-bit Touch Key Flash MCU
Oscillators
Variousꢀoscillatorꢀoptionsꢀofferꢀtheꢀuserꢀaꢀwideꢀrangeꢀofꢀfunctionsꢀaccordingꢀtoꢀtheirꢀvariousꢀ
applicationꢀrequirements.ꢀTheꢀflexibleꢀfeaturesꢀofꢀtheꢀoscillatorꢀfunctionsꢀensureꢀthatꢀtheꢀbestꢀ
optimisationꢀcanꢀbeꢀachievedꢀinꢀtermsꢀofꢀspeedꢀandꢀpowerꢀsaving.
Oscillator Overview
Theꢀdeviceꢀincludesꢀtwoꢀinternalꢀoscillators,ꢀaꢀlowꢀspeedꢀoscillatorꢀandꢀhighꢀspeedꢀoscillator.ꢀBothꢀ
canꢀbeꢀchosenꢀasꢀtheꢀclockꢀsourceꢀforꢀtheꢀmainꢀsystemꢀclockꢀhoweverꢀtheꢀslowꢀspeedꢀoscillatorꢀisꢀ
alsoꢀusedꢀasꢀaꢀclockꢀsourceꢀforꢀotherꢀfunctionsꢀsuchꢀasꢀtheꢀWatchdogꢀTimer,ꢀTimeꢀBaseꢀandꢀTimer/
EventꢀCounter.ꢀBothꢀoscillatorsꢀrequireꢀnoꢀexternalꢀcomponentsꢀforꢀtheirꢀimplementation.ꢀAllꢀ
oscillatorꢀoptionsꢀareꢀselectedꢀusingꢀregisters.ꢀTheꢀhighꢀspeedꢀoscillatorꢀprovidesꢀhigherꢀperformanceꢀ
butꢀcarriesꢀwithꢀitꢀtheꢀdisadvantageꢀofꢀhigherꢀpowerꢀrequirements,ꢀwhileꢀtheꢀoppositeꢀisꢀofꢀcourseꢀ
trueꢀforꢀtheꢀlowꢀspeedꢀoscillator.ꢀWithꢀtheꢀcapabilityꢀofꢀdynamicallyꢀswitchingꢀbetweenꢀfastꢀandꢀ
slowꢀsystemꢀclock,ꢀtheꢀdeviceꢀhasꢀtheꢀflexibilityꢀtoꢀoptimiseꢀtheꢀperformance/powerꢀratio,ꢀaꢀfeatureꢀ
especiallyꢀimportantꢀinꢀpowerꢀsensitiveꢀportableꢀapplications.
Type
Name
HIRC
LIRC
Freq.
ꢅMHz
ꢇꢄkHz
Inteꢁnal High Speed RC
Inteꢁnal Low Speed RC
Oscillator Types
System Clock Configuratios
Thereꢀareꢀtwoꢀsystemꢀoscillators,ꢀoneꢀhighꢀspeedꢀoscillatorsꢀandꢀoneꢀlowꢀspeedꢀoscillators.ꢀTheꢀhighꢀ
speedꢀoscillatorꢀisꢀaꢀfullyꢀinternalꢀ8MHzꢀRCꢀoscillator.ꢀTheꢀlowꢀspeedꢀoscillatorꢀisꢀaꢀfullyꢀinternalꢀ
32kHzꢀRCꢀoscillator.ꢀSelectingꢀwhetherꢀtheꢀlowꢀorꢀhighꢀspeedꢀoscillatorꢀisꢀusedꢀasꢀtheꢀsystemꢀ
oscillatorꢀisꢀimplementedꢀusingꢀtheꢀHLCLKꢀbitꢀandꢀCKS2~CKS0ꢀbitsꢀinꢀtheꢀSMODꢀregisterꢀandꢀasꢀ
theꢀsystemꢀclockꢀcanꢀbeꢀdynamicallyꢀselected.
Internal RC Oscillator – HIRC
TheꢀinternalꢀRCꢀoscillatorꢀisꢀaꢀfullyꢀintegratedꢀsystemꢀoscillatorꢀrequiringꢀnoꢀexternalꢀcomponents.ꢀ
TheꢀinternalꢀRCꢀoscillatorꢀhasꢀtheꢀfrequencyꢀofꢀ8MHzꢀ.Deviceꢀtrimmingꢀduringꢀtheꢀmanufacturingꢀ
processꢀandꢀtheꢀinclusionꢀofꢀinternalꢀfrequencyꢀcompensationꢀcircuitꢀisꢀusedꢀtoꢀensureꢀthatꢀtheꢀ
influenceꢀofꢀtheꢀpowerꢀsupplyꢀvoltage,ꢀtemperatureꢀandꢀprocessꢀvariationsꢀonꢀtheꢀoscillationꢀ
frequencyꢀareꢀminimised.ꢀ
Internal 32kHZ Oscillator – LIRC
TheꢀLIRCꢀisꢀaꢀfullyꢀself-containedꢀfreeꢀrunningꢀon-chipꢀRCꢀoscillatorꢀwithꢀaꢀtypicalꢀfrequencyꢀofꢀ
32kHzꢀatꢀ5V,ꢀrequiringꢀnoꢀexternalꢀcomponentsꢀforꢀitsꢀimplementation.ꢀDeviceꢀtrimmingꢀduringꢀ
theꢀmanufacturingꢀprocessꢀandꢀtheꢀinclusionꢀofꢀinternalꢀfrequencyꢀcompensationꢀcircuitsꢀareꢀusedꢀ
toꢀensureꢀthatꢀtheꢀinfluenceꢀofꢀtheꢀpowerꢀsupplyꢀvoltage,ꢀtemperatureꢀandꢀprocessꢀvariationsꢀonꢀ
theꢀoscillationꢀfrequencyꢀareꢀminimised.ꢀAfterꢀpowerꢀonꢀthisꢀLIRCꢀoscillatorꢀwillꢀbeꢀpermanentlyꢀ
enabled;ꢀthereꢀisꢀnoꢀprovisionꢀtoꢀdisableꢀtheꢀoscillatorꢀusingꢀregisterꢀbits.
Rev. 1.00
ꢄꢇ
�eꢀꢁꢂaꢁꢃ ꢄꢅꢆ ꢄ01ꢇ
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
