Datasheet

MANUFACTURERINFORMATIONBLOCKS
ACCESSMODES
bq27510-G1
SLUS927–APRIL2009..................................................................................................................................................................................................... www.ti.com
Occasionally,adataflashCLASSwillbelargerthanthe32-byteblocksize.Inthiscase,theDataFlashBlock()
commandisusedtodesignatewhich32-byteblockthedesiredlocationsresidein.Thecorrectcommand
addressisthengivenby0x40+offsetmodulo32.Forexample,toaccessTerminateVoltageintheGas
Gaugingclass,DataFlashClass()isissued80(0x50)tosettheclass.Becausetheoffsetis48,itmustresidein
thesecond32-byteblock.Hence,DataFlashBlock()isissued0x01tosettheblockoffset,andtheoffsetusedto
indexintotheBlockData()memoryareais0x40+48modulo32=0x40+16=0x40+0x10=0x50.
Readingandwritingsubclassdataareblockoperationsupto32bytesinlength.Ifduringawritethedatalength
exceedsthemaximumblocksize,thenthedataisignored.
Noneofthedatawrittentomemoryareboundedbythebq27510–thevaluesarenotrejectedbythefuelgauge.
Writinganincorrectvaluemayresultinhardwarefailureduetofirmwareprograminterpretationoftheinvalid
data.Thewrittendataispersistent,soapower-onresetdoesresolvethefault.
Thebq27510contains96bytesofuserprogrammabledataflashstorage:ManufacturerInfoBlockA,
ManufacturerInfoBlockB,ManufacturerInfoBlockC.Themethodforaccessingthesememorylocationsis
slightlydifferent,dependingonwhetherthedeviceisinUNSEALEDorSEALEDmodes.
WheninUNSEALEDmode,andwhen0x00hasbeenwrittentoBlockDataControl(),accessingtheManufacturer
InfoBlocksisidenticaltoaccessinggeneraldataflashlocations.First,aDataFlashClass()commandisusedto
setthesubclass,thenaDataFlashBlock()commandsetstheoffsetforthefirstdataflashaddresswithinthe
subclass.TheBlockData()commandcodescontainthereferenceddataflashdata.Whenwritingthedataflash,
achecksumisexpectedtobereceivedbyBlockDataChecksum().Onlywhenthechecksumisreceivedand
verifiedisthedataactuallywrittentodataflash.
Asanexample,thedataflashlocationforManufacturerInfoBlockBisdefinedashavingaSubclass=58and
anOffset=32through63(32byteblock).ThespecificationofClass=SystemDataisnotneededtoaddress
ManufacturerInfoBlockB,butisusedinsteadforgroupingpurposeswhenviewingdataflashinfointhe
bq27510evaluationsoftware.
WheninSEALEDmodeorwhen0x01BlockDataControl()doesnotcontain0x00,dataflashisnolonger
availableinthemannerusedinUNSEALEDmode.Ratherthanissuingsubclassinformation,adesignated
ManufacturerInformationBlockisselectedwiththeDataFlashBlock()command.Issuinga0x01,0x02,or0x03
withthiscommandcausesthecorrespondinginformationblock(A,B,orC,respectively)tobetransferredtothe
commandspace0x40…0x5fforeditingorreadingbythesystem.Uponsuccessfulwritingofchecksum
informationtoBlockDataChecksum(),themodifiedblockisreturnedtodataflash.Note:ManufacturerInfo
BlockAisread-onlywheninSEALEDmode.
Thebq27510providesthreesecuritymodes(FULLACCESS,UNSEALED,andSEALED)thatcontroldataflash
accesspermissionsaccordingtoTable6.Dataflashlocations,specifiedinTable7,areaccessibletotheuser.
Manufactureinformationreferstothethreereserved32-byteblocks.
Table6.DataFlashAccess
SecurityModeDataFlashManufacturer
Information
FULLACCESSR/WR/W
UNSEALEDR/WR/W
SEALEDNoneR(A);R/W(B,C)
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