资源描述：
《单片机毕业外文翻译.doc》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、Electricboilertemperaturesystem1.MCUAmicrocontroller(orMCU)isacomputer-on-a-chip.Itisatypeofmicroprocessoremphasizingself-sufficiencyandcost-effectiveness,incontrasttoageneral-purposemicroprocessor(thekindusedinaPC).Themajorityofcomputersystemsinusetodayareembeddedinothermachinery,suchastelephones,
2、clocks,appliances,vehicles,andinfrastructure.Anembeddedsystemusuallyhasminimalrequirementsformemoryandprogramlengthandmayrequiresimplebutunusualinput/outputsystems.Forexample,mostembeddedsystemslackkeyboards,screens,disks,printers,orotherrecognizableI/Odevicesofapersonalcomputer.Theymaycontrolelect
3、ricmotors,relaysorvoltages,andreadswitches,variableresistorsorotherelectronicdevices.Often,theonlyI/Odevicereadablebyahumanisasinglelight-emittingdiode,andseverecostorpowerconstraintscaneveneliminatethat.Incontrasttogeneral-purposeCPUs,microcontrollersdonothaveanaddressbusoradatabus,becausetheyinte
4、gratealltheRAMandnon-volatilememoryonthesamechipastheCPU.Becausetheyneedfewerpins,thechipcanbeplacedinamuchsmaller,cheaperpackage.Integratingthememoryandotherperipheralsonasinglechipandtestingthemasaunitincreasesthecostofthatchip,butoftenresultsindecreasednetcostoftheembeddedsystemasawhole.(Evenift
5、hecostofaCPUthathasintegratedperipheralsisslightlymorethanthecostofaCPU+externalperipherals,havingfewerchipstypicallyallowsasmallerandcheapercircuitboard,andreducesthelaborrequiredtoassembleandtestthecircuitboard).Thistrendleadstodesign.Amicrocontrollerisasingleintegratedcircuit,commonlywiththefoll
6、owingfeatures:centralprocessingunit-rangingfromsmallandsimple4-bitprocessorstosophisticated32-or64-bitprocessorsinput/outputinterfacessuchasserialports(UARTs)otherserialcommunicationsinterfaceslikeI²C,SerialPeripheralInterfaceandControllerAreaNetworkforsysteminterconnectperipheralssuchastimersandwa
7、tchdogRAMfordatastorageROM,EPROM,EEPROMorFlashmemoryforprogramstorageclockgenerator-oftenanoscillatorforaquartztimingcrystal,resonatororRCcircuitmanyincludeanalog-to-digitalconverters.Thisintegrationdrastic
