Holtek BS82B12A-3 - UART Interface; UART Exte�Nal Pin Inte�Facing

Rev. 1.20 116 January 23, 2015 Rev. 1.20 117 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
UART Interface
Thedevicescontainanintegratedfull-duplexasynchronousserialcommunicationsUARTinterface
thatenablescommunicationwithexternaldevicesthatcontainaserialinterface.TheUARTfunction
hasmanyfeaturesandcantransmitandreceivedataseriallybytransferringaframeofdatawith
eightorninedatabitspertransmissionaswellasbeingabletodetecterrorswhenthedatais
overwrittenorincorrectlyframed.TheUARTfunctionpossessesitsowninternalinterruptwhich
canbeusedtoindicatewhenareceptionoccursorwhenatransmissionterminates.
TheintegratedUARTfunctioncontainsthefollowingfeatures:
• Full-duplex,UniversalAsynchronousReceiverandTransmitter(UART)communication
• 8or9bitscharacterlength
• Even,oddornoparityoptions
• Oneortwostopbits
• Baudrategeneratorwith8-bitprescaler
• Parity,framing,noiseandoverrunerrordetection
• Supportforinterruptonaddressdetect(lastcharacterbit=1)
• Transmitterandreceiverenabledindependently
• 2-byteDeepFIFOReceiveDataBuffer
• TransmitandReceiveMultipleInterruptGenerationSources:

♦
TransmitterEmpty

♦
TransmitterIdle

♦
ReceiverFull

♦
ReceiverOverrun

♦
AddressModeDetect

♦
RXpinwake-upinterrupt(RXenable,RXfallingedge)
UART External Pin Interfacing
Tocommunicatewithanexternalserialinterface,theinternalUARThastwoexternalpinsknown
asTXandRX.TheTXandRXpinsaretheUARTtransmitterandreceiverpinsrespectively.Along
withtheUARTENbit,theTXENandRXENbits,ifset,willautomaticallysetuptheseI/Oorother
pin-sharedfunctionalpinstotheirrespectiveTXoutputandRXinputconditionsanddisableany
pull-highresistoroptionwhichmayexistontheTXorRXpins.WhentheTXorRXpinfunction
isdisabledbyclearingtheUARTENandTXENorRXENbit,theTXorRXpincanbeusedasa
generalpurposeI/Oorotherpin-sharedfunctionalpin.