标签: 24lc21

TheMicrochipTechnologyInc.24LC21isa1K-bit(128x8)dualmodeserialEEPROMthatwasdevelopedprimarilyforuseincomputermonitors.Thispartwasdevelopedwithinputsfromseveralcomputermonitormanufacturers,inaccordancewiththeVESA(VideoElectronicsStandardsAssociation)monitorcommittee.ThiscommitteehasdevelopedaserialcommunicationprotocolcalledDataDisplayChannel(DDC)whichwascreatedtoeliminatetheneedtochangedipswitcheswhenconfiguringanewsystemoraddinganewmonitororvideocard.The24LC21deviceisusedinthemonitortostoreandtransmittheEDID(extendeddisplayID)tablewhichcontainsallset-upparametersneededbythevideocardtooperatewithaparticularmonitor.Withthissystem,theusercannowpluganycompatiblemonitorintoanycompatiblegraphicsboardandthegraphicsboardwillautomaticallyknowwhattypeofmonitorisbeingusedandconfigureitselfaccordingly.ThisautomaticconfigurationisthecornerstoneforMicrosoft’s‘PlugandPlay’capabilitybeingbuiltintothenew‘Windows95’release.AN610Usingthe24LC21DualModeSerialEEPROMTRANSMITONLYMODE(DDC1)Author:BruceNegleyMemoryProductsDivisionThe24LC21willalwayspower-upinthetransmitonlymode.Inthismode,the24LC21willoutputonebitofdataattheSDApinforeveryrisingedgeontheVCLKINTRODUCTIONpin.Thedatawillbetransmittedin8-bitwords,with……