HT66F20 datasheet(200/298 Pages) HOLTEK

200 / 298 page

Rev. 1.90

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HT66F20/HT66F30/HT66F40/HT66F50/HT66F60

HT66FU30/HT66FU40/HT66FU50/HT66FU60

Enhanced A/D Flash Type 8-Bit MCU with EEPROM

HT66F20/HT66F30/HT66F40/HT66F50/HT66F60

HT66FU30/HT66FU40/HT66FU50/HT66FU60

Enhanced A/D Flash Type 8-Bit MCU with EEPROM

I2C Bus Read/Write Signal

TheSRWbitintheSIMC1registerdefineswhethertheslavedevicewishestoreaddatafromthe

I2CbusorwritedatatotheI2Cbus.Theslavedeviceshouldexaminethisbittodetermineifitisto

beatransmitterorareceiver.IftheSRWflagis1thenthisindicatesthatthemasterdevicewishesto

readdatafromtheI2Cbus,thereforetheslavedevicemustbesetuptosenddatatotheI2Cbusasa

transmitter.IftheSRWflagis0thenthisindicatesthatthemasterwishestosenddatatotheI2Cbus,

thereforetheslavedevicemustbesetuptoreaddatafromtheI2Cbusasareceiver.

I2C Bus Slave Address Acknowledge Signal

Afterthemasterhastransmittedacallingaddress,anyslavedeviceontheI2Cbus,whose

owninternaladdressmatchesthecallingaddress,mustgenerateanacknowledgesignal.The

acknowledgesignalwillinformthemasterthataslavedevicehasaccepteditscallingaddress.Ifno

acknowledgesignalisreceivedbythemasterthenaSTOPsignalmustbetransmittedbythemaster

toendthecommunication.WhentheHAASflagishigh,theaddresseshavematchedandtheslave

devicemustchecktheSRWflagtodetermineifitistobeatransmitterorareceiver.IftheSRWflag

ishigh,theslavedeviceshouldbesetuptobeatransmittersotheHTXbitintheSIMC1register

shouldbesetto"1".IftheSRWflagislow,thenthemicrocontrollerslavedeviceshouldbesetupas

areceiverandtheHTXbitintheSIMC1registershouldbesetto"0".

I2C Bus Data and Acknowledge Signal

Thetransmitteddatais8-bitswideandistransmittedaftertheslavedevicehasacknowledged

receiptofitsslaveaddress.TheorderofserialbittransmissionistheMSBfirstandtheLSBlast.

Afterreceiptof8-bitsofdata,thereceivermusttransmitanacknowledgesignal,level0,beforeit

canreceivethenextdatabyte.Iftheslavetransmitterdoesnotreceiveanacknowledgebitsignal

fromthemasterreceiver,thentheslavetransmitterwillreleasetheSDAlinetoallowthemaster

tosendaSTOPsignaltoreleasetheI2CBus.ThecorrespondingdatawillbestoredintheSIMD

SIMDregister.Ifsetupasareceiver,theslavedevicemustreadthetransmitteddatafromtheSIMD

Whentheslavereceiverreceivesthedatabyte,itmustgenerateanacknowledgebit,knownas

TXAK,onthe9thclock.Theslavedevice,whichissetupasatransmitterwillchecktheRXAKbit

intheSIMC1registertodetermineifitistosendanotherdatabyte,ifnotthenitwillreleasethe

SDAlineandawaitthereceiptofaSTOPsignalfromthemaster.

HT66F20 Datasheet(PDF) 200 Page - Holtek Semiconductor Inc