标签: pic16c74

pic16c74单片机在湿度检测系统中的应用.pdf

Thisapplicationnotedescribesthebasicissuesthatneedtobeaddressedinordertoimplementdigitalsig-nalprocessingsystemsusingthePIC16C74andprovidesapplicationcodemodulesandexamplesforDTMFtonegeneration,a60Hznotchfilter,andasimplePIDcompensatorforcontrolsystems.TheseroutinescanalsobeusedwithotherPIC16C6XandPIC16C7XXXprocessorswithminormodificationsandtheadditionofexternalanalogI/Odevices.Theuseofgeneralpurposemicrocontrollersforlow-enddigitalsignalprocessingapplicationshasbecomemorecommonplacethesedayswiththeavail-abilityofhigherspeedprocessors.SincemostsignalprocessingsystemsconsistofahostprocessoranddedicatedDSPchip,theuseofasinglemicrocontrollertoperformboththesefunctionsprovidesasimplerandlowercostsolution.Inaddition,thesinglechipdesignwillconsumelesspowerwhichisidealforbatterypoweredapplications.ThePIC16C74withitson-chipA/D,PWMmodule,andfastCPUisanidealcandidateforuseintheselow-bandwidthsignalprocessingapplications.AtypicalsignalprocessingsystemincludesanA/Dconverter,D/Aconverter,andCPUthatperformsthesignalprocessingalgorithmasshowninFigure1.AN616DigitalSignalProcessingwiththePIC16C74Theinputsignal,x(t),isrstpassedthroughaninputAuthor:DariusMostowlter(commonlycalledtheanti-aliasinglter)whoseDesignConsultantfunctionistobandlimitthesignaltobelowtheNyquistrate(onehalfthesamplingfrequency)topreventaliasing.ThesignalisthendigitizedbytheA/DINTRODUCTION……