Holtek BS82B12A-3 - Page 120

Rev. 1.20 120 January 23, 2015 Rev. 1.20 121 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
Bit2 RXIF:ReceiveRXRdataregisterstatus
0:RXRdataregisterisempty
1:RXRdataregisterhasavailabledata
TheRXIFagisthereceivedataregisterstatusag.Whenthisreadonlyagis"0",
itindicatesthattheRXRreaddataregisterisempty.Whentheagis"1",itindicates
thattheRXRreaddataregistercontainsnewdata.Whenthecontentsoftheshift
registeraretransferredtotheRXRregister,aninterruptisgeneratedifRIE=1inthe
UCR2register.Ifoneormoreerrorsaredetectedinthereceivedword,theappropriate
receive-relatedagsNF,FERR,and/orPERRaresetwithinthesameclockcycle.The
RXIFagisclearedwhentheUSRregisterisreadwithRXIFset,followedbyaread
fromtheRXRregister,andiftheRXRregisterhasnodataavailable.
Bit1 TIDLE:Transmissionidle
0:Datatransmissionisinprogress(databeingtransmitted)
1:Nodatatransmissionisinprogress(transmitterisidle)
TheTIDLEflagisknownasthetransmissioncompleteflag.Whenthisreadonly
agis"0",itindicatesthatatransmissionisinprogress.Thisagwillbesetto"1"
whentheTXIFagis"1"andwhenthereisnotransmitdataorbreakcharacterbeing
transmitted.WhenTIDLEisequalto"1",theTXpinbecomesidlewiththepinstate
inlogichighcondition.TheTIDLEagisclearedbyreadingtheUSRregisterwith
TIDLEsetandthenwritingtotheTXRregister.Theagisnotgeneratedwhenadata
characterorabreakisqueuedandreadytobesent.
Bit0 TXIF:TransmitTXRdataregisterstatus
0:Characterisnottransferredtothetransmitshiftregister
1:Characterhastransferredtothetransmitshiftregister(TXRdataregisterisempty)
TheTXIFagisthetransmitdataregisteremptyag.Whenthisreadonlyagis"0",
itindicatesthatthecharacterisnottransferredtothetransmittershiftregister.When
theagis"1",itindicatesthatthetransmittershiftregisterhasreceivedacharacter
fromtheTXRdataregister.TheTXIFflagisclearedbyreadingtheUARTstatus
register(USR)withTXIFsetandthenwritingtotheTXRdataregister.Notethat
whentheTXENbitisset,theTXIFagbitwillalsobesetsincethetransmitdata
registerisnotyetfull.