Holtek HT66F0175 - Page 160

Rev. 1.50 160 August 28, 2017 Rev. 1.50 161 August 28, 2017
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
Bit2 TXBRK:Transmitbreakcharacter
0:Nobreakcharacteristransmitted
1:Breakcharacterstransmit
TheTXBRKbitistheTransmitBreakCharacterbit.Whenthisbitisequalto“0”,
therearenobreakcharactersandtheTXpinoperatsnormally.Whenthebitisequalto
“1”,therearetransmitbreakcharactersandthetransmitterwillsendlogiczeros.When
thisbitisequalto“1”,afterthebuffereddatahasbeentransmitted,thetransmitter
outputisheldlowforaminimumofa13-bitlengthanduntiltheTXBRKbitisreset.
Bit1 RX8:Receivedatabit8for9-bitdatatransferformat(readonly)
Thisbitisonlyusedif9-bitdatatransfersareused,inwhichcasethisbitlocationwill
storethe9
th
bitofthereceiveddataknownasRX8.TheBNObitisusedtodetermine
whetherdatatransfesarein8-bitor9-bitformat.
Bit0 TX8:Transmitdatabit8for9-bitdatatransferformat(writeonly)
Thisbitisonlyusedif9-bitdatatransfersareused,inwhichcasethisbitlocation
willstorethe9
th
bitofthetransmitteddataknownasTX8.TheBNObitisusedto
determinewhetherdatatransfesarein8-bitor9-bitformat.
UCR2 Register
TheUCR2registeristhesecondoftheUARTcontrolregistersandservesseveralpurposes.One
ofitsmainfunctionsistocontrolthebasicenable/disableoperationiftheUARTTransmitterand
ReceiveraswellasenablingthevariousUARTinterruptsources.Theregisteralsoservestocontrol
thebaudratespeed,receiverwake-upfunctionenableandtheaddressdetectfunctionenable.
Furtherexplanationoneachofthebitsisgivenbelow.
Bit 7 6 5 4 3 2 1 0
Name TXEN RXEN BRGH ADDEN WAKE RIE TIIE TEIE
R/W R/W R/W R/W R/W R/W R/W R/W R/W
POR 0 0 0 0 0 0 0 0
Bit7 TXEN:UARTTransmitterenablecontrol
0:UARTTransmitterisdisabled
1:UARTTransmitterisenabled
TheTXENbitistheTransmitterEnableBit.Whenthisbitisequalto“0”,the
transmitterwillbedisabledwithanypendingdatatransmissionsbeingaborted.In
additionthebufferswillbereset.InthissituationtheTXpinwillbeotherpin-shared
functionalpin.IftheTXENbitisequalto“1”andtheUARTENbitisalsoequalto
1,thetransmitterwillbeenabledandtheTXpinwillbecontrolledbytheUART.
ClearingtheTXENbitduringatransmissionwillcausethedatatransmissiontobe
abortedandwillresetthetransmitter.Ifthissituationoccurs,theTXpinwillbeother
pin-sharedfunctionalpin.
Bit6 RXEN:UARTReceiverenablecontrol
0:UARTReceiverisdisabled
1:UARTReceiverisenabled
TheRXENbitistheReceiverEnableBit.Whenthisbitisequalto“0”,thereceiver
willbedisabledwithanypendingdatareceptionsbeingaborted.Inadditionthe
receiverbufferswillbereset.InthissituationtheRXpinwillbeotherpin-shared
functionalpin.IftheRXENbitisequalto“1”andtheUARTENbitisalsoequal
to1,thereceiverwillbeenabledandtheRXpinwillbecontrolledbytheUART.
ClearingtheRXENbitduringareceptionwillcausethedatareceptiontobeaborted
andwillresetthereceiver.Ifthissituationoccurs,theRXpinwillbeotherpin-shared
functionalpin.