BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
Touch Key Interrupt
Eachꢀtouchꢀkeyꢀmodule,ꢀwhichꢀconsistsꢀofꢀfourꢀtouchꢀkeys,ꢀhasꢀtwoꢀindependentꢀinterrupts,ꢀoneꢀforꢀ
eachꢀofꢀthe,ꢀ16-bitꢀC/Fꢀcounterꢀandꢀtimeꢀslotꢀcounter.
Theꢀtimeꢀslotꢀcounterꢀinterruptꢀhasꢀitsꢀownꢀinterruptꢀvectorꢀwhileꢀtheꢀ16-bitꢀC/Fꢀcounterꢀinterruptsꢀ
areꢀcontainedꢀwithinꢀtheꢀMulti-functionꢀinterruptsꢀandꢀthereforeꢀdoꢀnotꢀhaveꢀtheirꢀownꢀvector.ꢀCareꢀ
mustꢀbeꢀtakenꢀduringꢀprogrammingꢀasꢀtheꢀ16-bitꢀC/Fꢀcounterꢀinterruptꢀflagsꢀcontainedꢀwithinꢀtheꢀ
Multi-functionꢀinterruptsꢀwillꢀnotꢀbeꢀautomaticallyꢀresetꢀuponꢀentryꢀintoꢀtheꢀinterruptꢀserviceꢀroutineꢀ
butꢀratherꢀmustꢀbeꢀresetꢀmanuallyꢀbyꢀtheꢀapplicationꢀprogram.ꢀMoreꢀdetailsꢀregardingꢀtheꢀtouchꢀkeyꢀ
interruptsꢀareꢀlocatedꢀinꢀtheꢀinterruptꢀsectionꢀofꢀtheꢀdatasheet.
Programming Considerations
Afterꢀtheꢀrelevantꢀregistersꢀareꢀsetup,ꢀtheꢀtouchꢀkeyꢀdetectionꢀprocessꢀisꢀinitiatedꢀtheꢀchangingꢀtheꢀ
MnSTꢀbitꢀfromꢀlowꢀtoꢀhigh.ꢀThisꢀwillꢀenableꢀandꢀsynchroniseꢀallꢀrelevantꢀoscillators.ꢀTheꢀMnRCOVꢀ
flag,ꢀwhichꢀisꢀtheꢀtimeꢀslotꢀcounterꢀflagꢀwillꢀgoꢀhighꢀandꢀremainꢀhighꢀuntilꢀtheꢀcounterꢀoverflows.ꢀ
Whenꢀthisꢀhappensꢀanꢀinterruptꢀsignalꢀwillꢀbeꢀgenerated.
Whenꢀtheꢀexternalꢀtouchꢀkeyꢀsizeꢀandꢀlayoutꢀareꢀdefined,ꢀtheirꢀrelatedꢀcapacitancesꢀwillꢀthenꢀ
determineꢀtheꢀsensorꢀoscillatorꢀfrequency.
Rev. 1.20
120
�ꢀꢁꢀst 10ꢂ 2012
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
