Rev. 1.80 1 January 16, 2014 HT24LC08 CMOS 8K 2-Wire Serial EEPROM Features • Operating voltage: 1.8V~5.5V for temperature -40°C to +85°C • Low power consumption – Operation: 5mA max. – Standby: 3μA max. • Internal organization: 1024×8 • 2-wire serial interface • Write cycle time: 5ms max. • Automatic erase-before-write operation • Partial page write allowed • 16-byte Page Write Mode • Write operation with built-in timer • Hardware controlled write protection • 40-year data retention • 10 6 rewrite cycles per word • 8-pin DIP/SOP/TSSOP package General Description The HT24LC08 is a 8K-bit serial read/write non- volatile memory device using the CMOS floating gate process. Its 8192 bits of memory are organized into 1024 words and each word is 8 bits. The device is optimized for use in many industrial and commercial applications where low power and low voltage operation are essential. Up to two HT24LC08 devices may be connected to the same two-wire bus. The HT24LC08 is guaranteed for 1M erase/write cycles and 40-year data retention. Block Diagram I / O C o n t r o l L o g i c M e m o r y C o n t r o l L o g i c S C L S D A A d d r e s s C o u n t e r A 0 ~ A 2 V S S X D E C E E P R O M A r r a y P a g e B u f f e r Y D E C S e n s e A M P R / W C o n t r o l H V P u m p W P V C C Pin Assignment 1 2 3 4 8 7 6 5 H T 2 4 L C 0 8 8 D I P - A / S O P - A / T S S O P - A A 0 A 1 A 2 V S S V C C W P S C L S D A Pin Description Pin Name I/O Description A0~A2 I Address inputs. A0, A1 not connected. SDA I/O Serial data SCL I Serial clock input WP I Write protect VSS — Negative power supply, ground VCC — Positive power supply
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Rev. 1.80 1 January 16, 2014 Rev. 1.82 PB January 16, 2014
General DescriptionTheHT24LC08 is a8K-bit serial read/writenon-volatilememorydeviceusingtheCMOSfloatinggateprocess.Its8192bitsofmemoryareorganizedinto1024wordsandeachword is8bits.Thedevice isoptimizedforuseinmanyindustrialandcommercialapplicationswhere low power and low voltageoperationareessential.UptotwoHT24LC08devicesmaybeconnected to the same two-wirebus.TheHT24LC08isguaranteedfor1Merase/writecyclesand40-yeardataretention.
Pin DescriptionPin Name I/O DescriptionA0~A2 I Address inputs. A0, A1 not connected.SDA I/O Serial dataSCL I Serial clock inputWP I Write protectVSS — Negative power supply, groundVCC — Positive power supply
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Absolute Maximum RatingsSupplyVoltage.........................VSS−0.3VtoVSS+6.0VInputVoltage............................ VSS−0.3VtoVCC+0.3V
VCC Operating Voltage — -40°C to +85°C 1.8 — 5.5 VICC1 Operating Current 5V Read at 400kHz — — 2 mAICC2 Operating Current 5V Write at 400kHz — — 5 mAVIL Input Low Voltage — — -0.45 — 0.3VCC VVIH Input High Voltage — — 0.7VCC — VCC+0.5 V
• Serialdata–SDAThe SDA pin is bidirectional for serial datatransfer.Thepinisopen-draindrivenandmaybewired-ORwithanynumberofotheropen-drainoropencollectordevices.
• AcknowledgeAll addresses and data words are seriallytransmitted to and from theEEPROM in8-bitwords.TheEEPROMsendsazerotoacknowledgethatithasreceivedeachword.Thishappensduringtheninthclockcycle.
The8thbitdeviceaddressistheread/writeoperationselectbit.Areadoperation is initiated if thisbit ishighandawriteoperationisinitiatedifthisbitislow.
If thecomparisonof thedeviceaddresssucceedtheEEPROMwilloutputazeroatACKbit. Ifnot, thechipwillreturntoastandbystate.
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Write Operations• BytewriteAwrite operation requires an8-bit datawordaddress following thedeviceaddresswordandacknowledgment.Upon receiptof thisaddress,theEEPROMwill again respondwith a zeroand thenclock in thefirst8-bitdataword.Afterreceivingthe8-bitdataword, theEEPROMwilloutputazeroandtheaddressingdevice,suchasamicrocontroller,mustterminatethewritesequencewithastopcondition.At this timetheEEPROMentersaninternally-timedwritecycle tothenon-volatilememory.AllinputsaredisabledduringthiswritecycleandEEPROMwillnot responduntilthewriteiscompleted(refertoBytewritetiming).
• PagewriteThe8KEEPROMiscapableofa16-bytepagewrite.Apagewriteisinitiatedinthesamewayasabytewrite,butthemicrocontrollerdoesnotsendastopconditionafterthefirstdatawordisclockedin.Instead,after theEEPROMacknowledgesthereceiptof thefirstdataword, themicrocontrollercan transmit up to 15more datawords.TheEEPROMwillrespondwithazeroaftereachdatawordreceived.Themicrocontrollermustterminatethepagewritesequencewithastopcondition(refertoPagewritetiming).Thedatawordaddresslowerfourbitsareinternallyincremented following the receiptof eachdataword.Thehigherdatawordaddressbitsarenotincremented, retaining thememory page rowlocation.
• ReadoperationsTheHT24LC08supports three readoperations,namely, current address read, randomaddressreadandsequential read.Duringreadoperationexecution,theread/writeselectbitshouldbesetto"1".
• CurrentaddressreadTheinternaldatawordaddresscountermaintainsthe lastaddressaccessedduring the last readorwriteoperation,incrementedbyone.Thisaddressstaysvalidbetweenoperationsaslongasthechippowerismaintained.Theaddressrolloverduringreadfromthelastbyteofthelastmemorypagetothefirstbyteofthefirstpage.Theaddressrolloverduringwritefromthelastbyteofthecurrentpagetothefirstbyteofthesamepage.Oncethedeviceaddresswiththeread/writeselectbitsettooneisclocked inandacknowledgedby theEEPROM,thecurrentaddressdataword isseriallyclockedout.Themicrocontrollershouldrespondwitha"noACK"signal(high)followedbyastopcondition(refertoCurrentreadtiming).
• RandomreadA random read requires a dummybytewritesequenceto loadin thedatawordaddresswhichis then clocked in and acknowledged by theEEPROM.Themicrocontrollermustthengenerateanother start condition.Themicrocontrollernow initiatesacurrentaddress readbysendingadeviceaddresswith the read/write selectbithigh.TheEEPROMacknowledges thedeviceaddressandseriallyclocksoutthedataword.Themicrocontrollershouldrespondwitha"noACK"signal(high)followedbyastopcondition.(refertoRandomreadtiming).
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• SequentialreadSequential readsare initiatedbyeitheracurrentaddressreadorarandomaddressread.After themicrocontrollerreceivesadataword, it respondswithanacknowledgment.AslongastheEEPROMreceivesanacknowledgment, itwillcontinue toincrementthedatawordaddressandseriallyclock
out sequential datawords.When thememoryaddresslimitisreached,thedatawordaddresswillrolloverand thesequential readcontinues.Thesequential readoperation is terminatedwhenthemicrocontrollerrespondswitha"noACK"signal(high)followedbyastopcondition.
The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek's products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw.