分段线性插值PIC12/14/16系列微控制器

Theembeddedsystemsworldisfilledwithsensingand

measurementtechniquesthatpresentnon-linear

outputresults.Ifthesensingtechniqueiswellcharac-

terized,amathematicaltransferfunctioncanbeused

tocorrectandlinearizethesensoroutput.Inmany

cases,thesefunctionscontaincomplexpolynomialand

exponentialfunctions,placingagreatburdenonthe

programmemory,RAMandexecutionspeedofmost

low-costmicrocontrollers.

ThisapplicationnotewillexploreasimplePiecewise

LinearInterpolationtechniquethatisoftenemployedto

linearizeasensor'soutput.Thistechniquehasmany

advantagesinfasterexecutionspeedusingasimple

look-uptableandsignificantlyreducedprogram

memoryandRAMrequirements.However,this

techniquecanintroduceaconsiderableerrorcompo-

nentwithcertaintransferfunctions.Therefore,the

designengineerneedstounderstandthebenefitsand

limitationsofthistechnique,whichwillbeexplainedin

thisapplicationnote.AN942PiecewiseLinearInterpolationonPIC12/14/16SeriesMicrocontrollersEQUATION1:STEINHART-HARTAuthor:JohnDayandStevenBibleMicrochipTechnologyInc.1=A+B(1nR)+(1nR)3TKSolvingfortemperatureindegreesCelsi