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4.1.2EXTENDEDDATACOMMANDS
bq27500
bq27501
System-SideImpedanceTrack™FuelGauge
SLUS785–SEPTEMBER2007
4.1.1.16MaxLoadCurrent():0x1e/0x1f
Thisread-onlyfunctionreturnsasignedintegervalue,inunitsofmA,ofthemaximumloadconditions.
TheMaxLoadCurrent()isanadaptivemeasurementwhichisinitiallyreportedasthemaximumload
currentprogrammedinInitialMaxLoadCurrent.IfthemeasuredcurrentisevergreaterthanInitialMax
LoadCurrent,thenMaxLoadCurrent()updatestothenewcurrent.MaxLoadCurrent()isreducedtothe
averageofthepreviousvalueandInitialMaxLoadCurrentwheneverthebatteryischargedtofullafter
apreviousdischargetoanSOClessthan50%.Thispreventsthereportedvaluefrommaintainingan
unusuallyhighvalue.
4.1.1.17MaxLoadTimeToEmpty():0x20/0x21
Thisread-onlyfunctionreturnsanunsignedintegervalueofthepredictedremainingbatterylifeatthe
maximumloadcurrentdischargerate,inminutes.Avalueof65535indicatesthatthebatteryisnotbeing
discharged.
4.1.1.18AvailableEnergy():0x22/0x23
Thisread-onlyfunctionreturnsanunsignedintegervalueofthepredictedchargeorenergyremainingin
thebattery.ThevalueisreportedinunitsofmWh.
4.1.1.19AveragePower():0x24/0x25
Thisread-wordfunctionreturnsanunsignedintegervalueoftheaveragepowerofthecurrentdischarge.
Avalueof0indicatesthatthebatteryisnotbeingdischarged.ThevalueisreportedinunitsofmW.
4.1.1.20TimeToEmptyAtConstantPower():0x26/0x27
Thisread-onlyfunctionreturnsanunsignedintegervalueofthepredictedremainingoperatingtimeifthe
batteryisdischargedattheAveragePower()valueinminutes.Avalueof65535indicates
AveragePower()=0.ThefuelgaugeautomaticallyupdatesTimeToEmptyatContantPower()basedonthe
AveragePower()valueevery1s.
4.1.1.21CycleCount():0x2a/0x2b
Thisread-onlyfunctionreturnsanunsignedintegervalueofthenumberofcyclesthebatteryhas
experiencedwitharangeof0to65535.Onecycleoccurswhenaccumulateddischarge≥CCThreshold.
4.1.1.22StateOfCharge():0x2c/0x2d
Thisread-onlyfunctionreturnsanunsignedintegervalueofthepredictedremainingbatterycapacity
expressedasapercentageofFullChargeCapacity(),witharangeof0to100%.
Extendedcommandsofferadditionalfunctionalitybeyondthestandardsetofcommands.Theyareusedin
thesamemanner;howeverunlikestandardcommands,extendedcommandsarenotlimitedto2-byte
words.Thenumberofcommandsbytesforagivenextendedcommandrangesinsizefromsingleto
multiplebytes,asspecifiedinTable4-5.FordetailsontheSEALEDandUNSEALEDstates,see
Section4.4AccessModes.
Table4-5.ExtendedDataCommands
COMMANDSEALEDUNSEALED
NAMEUNITS
CODEACCESS
(1)(2)
ACCESS
(1)(2)
ReservedRSVD0x34...0x3bN/ARR
DesignCapacity()DCAP0x3c/0x3dmAhRR
DataFlashClass()
(2)
DFCLS0x3eN/AN/AR/W
DataFlashBlock()
(2)
DFBLK0x3fN/AR/WR/W
Authenticate()/BlockData()A/DF0x40…0x53N/AR/WR/W
AuthenticateCheckSum()/BlockData()ACKS/DFD0x54N/AR/WR/W
(1)SEALEDandUNSEALEDstatesareenteredviacommandstoCNTL0x00/0x01.
(2)Insealedmode,dataflashCANNOTbeaccessedthroughcommands0x3eand0x3f.
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