KEELOQ®数据编码器振荡器校准

SeveralKEELOQEncodersofrecentintroduction,offer

theabilitytocalibratetheinternalRCclockoscillator,

uponwhichallthedevicetimingsarebased.Atthetime

ofwritingthisApplicationNote,therearefiveKEELOQ

devicesofferingthisfeature:

•HCS101-fixedcodeencoder

•HCS201-lowcosthoppingcodeencoder

•HCS362-advancedhoppingcodeencoder

•HCS410-hoppingcodetranscoder

•HCS412-hoppingcodetranscoder

WhiletherespectiveEncoderDataSheetsshow

“where”thecalibrationvalueisstoredinthedevice

EEPROM,thisApplicationNotewillconcentrateon

“howto”determinethebestcalibrationvalue.AN824KEELOQEncodersOscillatorCalibrationTypically,thisoscillatorprovidestheclockfrequencyAuthor:LucioDiJasiowithawidetolerance(upto-30%/+50%)andthatMicrochipTechnologyInc.reflectsinampletolerancesonthetransmissionbaudrate,LEDflashingand,ingeneral,onmostdevicetim-ings.Further,beingasimpleRCclockcircuit,itisaffectedby