單片機外文文獻翻譯

單片機單片機也被稱為微控制器（MicrocontrollerUnit），常用英文字母的縮寫MCU表示單片機，它最早是被用在工業(yè)控制領域。單片機由芯片內僅有CPU的專用處理器發(fā)展而來。最早的設計理念是通過將大量外圍設備和CPU集成在一個芯片中，使計算機系統(tǒng)更小，更容易集成進復雜的而對體積要求嚴格的控制設備當中。INTEL的Z80是最早按照這種思想設計出的處理器，從此以后，單片機和專用處理器的發(fā)展便分道揚鑣。早期的單片機都是8位或4位的。其中最成功的是INTEL的8031，因為簡單可靠而性能不錯獲得了很大的好評。此后在8031上發(fā)展出了MCS51系列單片機系統(tǒng)?；谶@一系統(tǒng)的單片機系統(tǒng)直到現(xiàn)在還在廣泛使用。隨著工業(yè)控制領域要求的提高，開始出現(xiàn)了16位單片機，但因為性價比不理想并未得到很廣泛的應用。90年代后隨著消費電子產品大發(fā)展，單片機技術得到了巨大提高。隨著INTELi960系列特別是后來的ARM系列的廣泛應用，32位單片機迅速取代16位單片機的高端地位，并且進入主流市場。而傳統(tǒng)的8位單片機的性能也得到了飛速提高，處理能力比起80年代提高了數(shù)百倍。目前，高端的32位單片機主頻已經超過300MHz，性能直追90年代中期的專用處理器，而普通的型號出廠價格跌落至1美元，最高端[1]的型號也只有10美元。當代單片機系統(tǒng)已經不再只在裸機環(huán)境下開發(fā)和使用，大量專用的嵌入式操作系統(tǒng)被廣泛應用在全系列的單片機上。而在作為掌上電腦和手機核心處理的高端單片機甚至可以直接使用專用的Windows和Linux操作系統(tǒng)。單片機比專用處理器更適合應用于嵌入式系統(tǒng)，因此它得到了最多的應用。事實上單片機是世界上數(shù)量最多的計算機?，F(xiàn)代人類生活中所用的幾乎每件電子和機械產品中都會集成有單片機。手機、電話、計算器、家用電器、電子玩具、掌上電腦以及鼠標等電腦配件中都配有1-2部單片機。而個人電腦中也會有為數(shù)不少的單片機在工作。汽車上一般配備40多部單片機，復雜的工業(yè)控制系統(tǒng)上甚至可能有數(shù)百臺單片機在同時工作！單片機的數(shù)量不僅遠超過PC機和其他計算的總和，甚至比人類的數(shù)量還要多。單片機又稱單片微控制器,它不是完成某一個邏輯功能的芯片,而是把一個計算機系統(tǒng)集成到一個芯片上。相當于一個微型的計算機，和計算機相比，單片機只缺少了I/O設備。概括的講：一塊芯片就成了一臺計算機。它的體積小、質量輕、價格便宜、為學習、應用和開發(fā)提供了便利條件。同時，學習使用單片機是了解計算機原理與結構的最佳選擇。單片機內部也用和電腦功能類似的模塊，比如CPU，內存，并行總線，還有和硬盤作用相同的存儲器件，不同的是它的這些部件性能都相對我們的家用電腦弱很多，不過價錢也是低的，一般不超過10元即可......用它來做一些控制電器一類不是很復雜的工作足矣了。我們現(xiàn)在用的全自動滾筒洗衣機、排煙罩、VCD等等的家電里面都可以看到它的身影！......它主要是作為控制部分的核心部件。它是一種在線式實時控制計算機，在線式就是現(xiàn)場控制，需要的是有較強的抗干擾能力，較低的成本，這也是和離線式計算機的（比如家用PC）的主要區(qū)別。單片機芯片單片機是靠程序運行的，并且可以修改。通過不同的程序實現(xiàn)不同的功能，尤其是特殊的獨特的一些功能，這是別的器件需要費很大力氣才能做到的，有些則是花大力氣也很難做到的。一個不是很復雜的功能要是用美國50年代開發(fā)的74系列，或者60年代的CD4000系列這些純硬件來搞定的話，電路一定是一塊大PCB板！但是如果要是用美國70年代成功投放市場的系列單片機，結果就會有天壤之別！只因為單片機的通過你編寫的程序可以實現(xiàn)高智能，高效率，以及高可靠性！由于單片機對成本是敏感的，所以目前占統(tǒng)治地位的軟件還是最低級匯編語言，它是除了二進制機器碼以上最低級的語言了，既然這么低級為什么還要用呢？很多高級的語言已經達到了可視化編程的水平為什么不用呢？原因很簡單，就是單片機沒有家用計算機那樣的CPU，也沒有像硬盤那樣的海量存儲設備。此外，單片機在工商，金融，科研、教育，國防航空航天等領域都有著十分廣泛的用途。學習應用六大重要部分單片機學習應用的六大重要部分：一、總線：我們知道，一個電路總是由元器件通過電線連接而成的，在模擬電路中，連線并不成為一個問題，因為各器件間一般是串行關系，各器件之間的連線并不很多，但計算機電路卻不一樣，它是以微處理器為核心，各器件都要與微處理器相連，各器件之間的工作必須相互協(xié)調，所以需要的連線就很多了，如果仍如同模擬電路一樣，在各微處理器和各器件間單獨連線，則線的數(shù)量將多得驚人，所以在微處理機中引入了總線的概念，各個器件共同享用連線，所有器件的8根數(shù)據(jù)線全部接到8根公用的線上，即相當于各個器件并聯(lián)起來，但僅這樣還不行，如果有兩個器件同時送出數(shù)據(jù)，一個為0，一個為1，那么，接收方接收到的究竟是什么呢？這種情況是不允許的，所以要通過控制線進行控制，使器件分時工作，任何時候只能有一個器件發(fā)送數(shù)據(jù)（可以有多個器件同時接收）。器件的數(shù)據(jù)線也就被稱為數(shù)據(jù)總線，器件所有的控制線被稱為控制總線。在單片機內部或者外部存儲器及其它器件中有存儲單元，這些存儲單元要被分配地址，才能使用，分配地址當然也是以電信號的形式給出的，由于存儲單元比較多，所以，用于地址分配的線也較多，這些線被稱為地址總線。二、數(shù)據(jù)、地址、指令：之所以將這三者放在一起，是因為這三者的本質都是一樣的——數(shù)字，或者說都是一串‘0’和‘1’組成的序列。換言之，地址、指令也都是數(shù)據(jù)。指令：由單片機芯片的設計者規(guī)定的一種數(shù)字，它與我們常用的指令助記符有著嚴格的一一對應關系，不可以由單片機的開發(fā)者更改。地址：是尋找單片機內部、外部的存儲單元、輸入輸出口的依據(jù)，內部單元的地址值已由芯片設計者規(guī)定好，不可更改，外部的單元可以由單片機開發(fā)者自行決定，但有一些地址單元是一定要有的（詳見程序的執(zhí)行過程）。三、P0口、P2口和P3的第二功能用法：初學時往往對P0口、P2口和P3口的第二功能用法迷惑不解，認為第二功能和原功能之間要有一個切換的過程，或者說要有一條指令，事實上，各端口的第二功能完全是自動的，不需要用指令來轉換。如P3.6、P3.7分別是WR、RD信號，當微片理機外接RAM或有外部I/O口時，它們被用作第二功能，不能作為通用I/O口使用，只要一微處理機一執(zhí)行到MOVX指令，就會有相應的信號從P3.6或P3.7送出，不需要事先用指令說明。事實上‘不能作為通用I/O口使用’也并不是‘不能’而是（使用者）‘不會’將其作為通用I/O口使用。你完全可以在指令中按排一條SETBP3.7的指令，并且當單片機執(zhí)行到這條指令時，也會使P3.7變?yōu)楦唠娖?，但使用者不會這么去做，因為這通常會導致系統(tǒng)的崩潰。四、程序的執(zhí)行過程：單片機在通電復位后8051內的程序計數(shù)器（PC）中的值為‘0000’，所以程序總是從‘0000’單元開始執(zhí)行，也就是說：在系統(tǒng)的ROM中一定要存在‘0000’這個單元，并且在‘0000’單元中存放的一定是一條指令。五、堆棧：堆棧是一個區(qū)域，是用來存放數(shù)據(jù)的，這個區(qū)域本身沒有任何特殊之處，就是內部RAM的一部份，特殊的是它存放和取用數(shù)據(jù)的方式，即所謂的‘先進后出，后進先出’，并且堆棧有特殊的數(shù)據(jù)傳輸指令，即‘PUSH’和‘POP’，有一個特殊的專為其服務的單元，即堆棧指針SP，每當執(zhí)一次PUSH指令時，SP就（在原來值的基礎上）自動加1，每當執(zhí)行一次POP指令，SP就（在原來值的基礎上）自動減1。由于SP中的值可以用指令加以改變，所以只要在程序開始階段更改了SP的值，就可以把堆棧設置在規(guī)定的內存單元中，如在程序開始時，用一條MOVSP，#5FH指令，就時把堆棧設置在從內存單元60H開始的單元中。一般程序的開頭總有這么一條設置堆棧指針的指令，因為開機時，SP的初始值為07H，這樣就使堆棧從08H單元開始往后，而08H到1FH這個區(qū)域正是8031的第二、三、四工作寄存器區(qū)，經常要被使用，這會造成數(shù)據(jù)的混亂。不同作者編寫程序時，初始化堆棧指令也不完全相同，這是作者的習慣問題。當設置好堆棧區(qū)后，并不意味著該區(qū)域成為一種專用內存，它還是可以象普通內存區(qū)域一樣使用，只是一般情況下編程者不會把它當成普通內存用了。Single-chipSCMisalsoknownasmicro-controller(MicrocontrollerUnit),commonlyusedlettersoftheacronymMCUthatitwasfirstusedinindustrialcontrol.OnlyasinglechipbytheCPUchipdevelopedfromadedicatedprocessor.ThefirstdesignisbyalargenumberofperipheralsandCPUonachipinthecomputersystem,smaller,moreeasilyintegratedintoacomplexanddemandingonthevolumecontroldevicewhich.INTEL'sZ80isthefirstdesignedinaccordancewiththisideaprocessor,thenonthedevelopmentofmicrocontrolleranddedicatedprocessorshavepartedways.Are8-bitmicrocontrollerearlyor4bits.OneofthemostsuccessfulistheINTEL8031,forasimple,reliableandgoodperformancewasalotofpraise.Thendevelopedin8031outofMCS51MCUSystems.SCMsystemsbasedonthissystemuntilnowisstillwidelyused.Withtheincreasedrequirementsofindustrialcontrolfield,begana16-bitmicrocontroller,becausethecostisnotsatisfactorybuthavenotbeenverywidelyused.After90yearswiththegreatdevelopmentofconsumerelectronics,microcontrollertechnologyhasbeenahugeincrease.WithINTELi960series,especiallythelaterseriesofwidelyusedARM,32-bitmicrocontrollerquicklyreplacehigh-end16-bitMCUstatusandenterthemainstreammarket.Thetraditional8-bitmicrocontrollerperformancehavebeentherapidincreasecapacityincreasecomparedto80thenumberoftimes.Currently,high-end32-bitmicrocontrollerclockedover300MHz,theperformancecatchingthemid-90'sdedicatedprocessor,whiletheaveragemodelpricesfalltooneU.S.dollars,themosthigh-end[1]modelonly10dollars.ModernSCMsystemsarenolongeronlyinthedevelopmentanduseofbaremetalenvironment,alargenumberofproprietaryembeddedoperatingsystemiswidelyusedinthefullrangeofSCM.Thehandheldcomputersandcellphonesasthecoreprocessingofhigh-endmicrocontrollercanevenuseadedicatedWindowsandLinuxoperatingsystems.SCMismoresuitablethanthespecificprocessorusedinembeddedsystems,soitwasuptotheapplication.InfactthenumberofSCMistheworld'slargestcomputer.Modernhumanlifeusedinalmosteverypieceofelectronicandmechanicalproductswillbeintegratedsinglechip.Phone,telephone,calculator,homeappliances,electronictoys,handheldcomputersandcomputeraccessoriessuchasamousewitha1-2inboththeDepartmentofSCM.PersonalcomputerwillhavealargenumberofSCMinthework.Generalcarwithmorethan40SCM,complexindustrialcontrolsystemsmayevenhavehundredsofSCMinthesametimework!SCMisnotonlyfarexceedsthenumberofPCandothercomputingthesum,orevenmorethanthenumberofhumanbeingsSinglechip,alsoknownassingle-chipmicrocontroller,itisnotcompleteacertainlogicchips,buttoacomputersystemintegratedintoachip.Equivalenttoamicro-computer,andcomputerthanjustthelackofamicrocontrollerI/Odevices.Generaltalk:achipbecomesacomputer.Itssmallsize,lightweight,cheap,forthestudy,applicationanddevelopmentoffacilitiesprovided.Atthesametime,learningtousetheMCUistounderstandtheprincipleandstructureofthecomputerthebestchoice.SCMandthecomputerfunctionsinternallywithsimilarmodules,suchasCPU,memory,parallelbus,thesameeffectaswell,andharddiskmemorydevices,anddifferentisitsperformanceofthesecomponentswererelativelyweakmanyofourhomecomputer,butthepriceislow,usuallynotmorethan10yuanyoucandowithit......somecontrolforaclassisnotverycomplicatedelectricalworkisenoughof.Weareusingautomaticdrumwashingmachine,smokehood,VCDandsoonapplianceswhichcouldseeitsshadow!......ItisprimarilyasacontrolsectionofthecorecomponentsItisanonlinereal-timecontrolcomputer,control-lineisthatthesceneisneededisastrongeranti-jammingability,lowcost,andthisis,andoff-linecomputer(suchashomePC),themaindifference.Singlechip

MCUisthroughrunning,andcanbemodified.Throughdifferentprocedurestoachievedifferentfunctions,inparticularspecialuniquefeatures,thisisanotherdevicemucheffortneedstobedone,somegreateffortsareverydifficulttodo.Anotverycomplexfunctionsifthe50'swiththeUnitedStatesdeveloped74series,orthe60'sCD4000seriesofthesepurehardwarebuttoned,thenthecircuitmustbealargePCBboard!ButiftheUnitedStatesifthe70'swithaseriesofsuccessfulSCMmarket,theresultwillbeadrasticchange!Justbecauseyouarepreparedbymicrocomputerprogramscanachievehighintelligence,highefficiencyandhighreliability!Asthemicrocontrolleronthecost-sensitive,sonowthedominantsoftwareorthelowestlevelassemblylanguage,whichisthelowestlevelinadditiontomorethanbinarymachinecodelanguage,andassolowwhyistheuse?Manyhigh-levellanguagehasreachedthelevelofvisualprogrammingWhyisnotit?ThereasonissimplythatthereisnohomecomputerasasinglechipCPU,notashardasamassstoragedevice.Avisualizationofsmallhigh-levellanguageprogramwhichevenifonlyonebutton,willreachtensofKofsize!ForthehomePC'sharddriveintermsofnothing,butintermsoftheMCUisnotacceptable.SCMintheutilizationofhardwareresourcestobeveryhighforthejobsoalthoughtheoriginalisstillinthecompilationofalotofuse.Thesametoken,ifthegiantcomputeroperatingsystemandapplicationsrunuptogethomePC,homePC,alsocannotaffordto.Canbesaidthatthetwentiethcenturyacrossthethree"power"era,thatis,theageofelectricity,theelectronicageandhasenteredintothecomputerage.However,thiscomputer,usuallyreferstothepersonalcomputer,referredtoasPC.Itconsistsofthehost,keyboard,monitorandothercomponents.Anothertypeofcomputer,mostpeopledonotknowhow.Thiscomputeristogiveallkindsofintelligentmachinessinglechip(alsoknownasmicro-controller).Asthenamesuggests,thiscomputersystemtookonlyaminimalintegratedcircuit,canbeasimpleoperationandcontrol.Becauseitissmall,usuallyhiddeninthechargedmechanical"stomach"in.Itisinthedevice,likethehumanbrainplaysarole,itgoeswrong,thewholeplantwasparalyzed.Now,thismicrocontrollerhasaverybroadfieldofuse,suchassmartmeters,real-timeindustrialcontrol,communicationsequipment,navigationsystems,andhouseholdappliances.OnceallkindsofproductswereusingSCM,canservetoupgradetheeffectivenessofproducts,oftenintheproductnameprecededbytheadjective-"intelligent,"suchasintelligentwashingmachines.Nowsometechnicalpersonneloffactoriesorotheramateurelectronicsdeveloperstoengageinoutofcertainproducts,notthecircuitistoocomplicated,thatfunctionistoosimpleandcaneasilybecopied.Thereasonmaybestuckintheproductdidnotuseamicrocontrollerorotherprogrammablelogicdevice.SCMhistorySCMwasborninthelate20thcentury,70,experiencedSCM,MCU,SOCthreestages.

Firstmodel

1.SCMthesinglechipmicrocomputer(SingleChipMicrocomputer)stage,mainlyseekingthebestofthebestsingleformofembeddedsystemsarchitecture."Innovationmodel"success,layingtheSCMandgeneralcomputercompletelydifferentpathofdevelopment.Intheopenroadofindependentdevelopmentofembeddedsystems,IntelCorporationcontributed.2.MCUthemicro-controller(MicroControllerUnit)stage,themaindirectionoftechnologydevelopment:expandingtomeettheembeddedapplications,thetargetsystemrequirementsforthevariousperipheralcircuitsandinterfacecircuits,highlighttheobjectofintelligentcontrol.Itinvolvestheareasassociatedwiththeobjectsystem,therefore,thedevelopmentofMCU'sresponsibilityinevitablyfallsonelectrical,electronicsmanufacturers.Fromthispointofview,IntelfadedMCUdevelopmenthasitsobjectivefactors.InthedevelopmentofMCU,themostfamousmanufacturersasthenumberofPhilipsCorporation.Philipscompanyinembeddedapplications,itsgreatadvantage,theMCS-51single-chipmicro-computerfromtherapiddevelopmentofthemicro-controller.Therefore,whenwelookbackatthepathofdevelopmentofembeddedsystems,donotforgetIntelandPhilipsinHistory.

EmbeddedSystems

Embeddedsystemmicrocontrollerisanindependentdevelopmentpath,theMCUimportantfactorinthedevelopmentstage,isseekingapplicationstomaximizethesolutiononthechip;Therefore,thedevelopmentofdedicatedsinglechipSOCtrendofthenaturalform.Asthemicroelectronics,ICdesign,EDAtoolsdevelopment,applicationsystembasedonMCUSOCdesignhavegreaterdevelopment.Therefore,theunderstandingofthemicrocontrollerchipmicrocomputercanbe,extendedtothesingle-chipmicro-controllerapplications.MCUapplications

SCMnowpermeateallareasofourlives,whichisalmostdifficulttofindtracesofthefieldwithoutSCM.Missilenavigationequipment,aircraft,alltypesofinstrumentcontrol,computernetworkcommunicationsanddatatransmission,industrialautomation,real-timeprocesscontrolanddataprocessing,extensiveuseofvarioussmartICcard,civilianluxurycarsecuritysystem,videorecorder,camera,fullyautomaticwashingmachinecontrol,andprogram-controlledtoys,electronicpet,etc.,whichareinseparablefromthemicrocontroller.Nottomentiontheareaofrobotcontrol,intelligentinstruments,medicalequipmentwas.Therefore,theMCUlearning,developmentandapplicationofthelargenumberofcomputerapplicationsandintelligentcontrolofthescientists,engineers.

SCMiswidelyusedininstrumentsandmeters,householdappliances,medicalequipment,aerospace,specializedequipment,intelligentmanagementandprocesscontrolfields,roughlydividedintothefollowingseveralareas:1.IntheapplicationofIntelligentInstruments

SCMhasasmallsize,lowpowerconsumption,controllingfunction,expansionflexibility,theadvantagesofminiaturizationandeaseofuse,widelyusedinstrument,combiningdifferenttypesofsensorscanberealizedZhuruvoltage,power,frequency,humidity,temperature,flow,speed,thickness,angle,length,hardness,elemental,physicalpressuremeasurement.SCMmakesuseofdigitalinstruments,intelligence,miniaturization,andfunctionalitythanelectronicordigitalcircuitsmorepowerful.Suchasprecisionmeasuringequipment(powermeter,oscilloscope,variousanalyticalinstrument).2.Intheindustrialcontrolapplication

WiththeMCUcanconstituteavarietyofcontrolsystems,dataacquisitionsystem.Suchasfactoryassemblylineofintelligentcontrol3.InHouseholdAppliances

canbesaidthattheappliancesarebasicallyusingSCM,praisefromtheelectricrice,washingmachines,refrigerators,airconditioners,colorTV,andotheraudiovideoequipment,totheelectronicweighingequipment,varied,andomnipresent.

4.Inthefieldofcomputernetworksandcommunicationsapplications

MCUgeneralwithmoderncommunicationinterface,canbeeasywiththecomputerdatacommunication,networkingandcommunicationsincomputerapplicationsbetweendeviceshadexcellentmaterialconditions,arebasicallyallcommunicationequipmenttoachieveacontrolledbyMCUfrommobilephone,telephone,mini-program-controlledswitchboards,buildingautomatedcommunicationscallsystem,trainradiocommunication,tothedailyworkcanbeseeneverywhereinthemobilephones,trunkedmobileradio,walkie-talkies,etc..5.Microcomputerinthefieldofmedicaldeviceapplications

SCMintheuseofmedicaldevicesisalsoquiteextensive,suchasmedicalrespirator,thevariousanalyzers,monitors,ultrasounddiagnosticequipmentandhospitalbeds,etc.callsystem.

6.Inavarietyofmajorappliancesinthemodularapplications

Designedtoachievesomespecialsinglespecificfunctiontobemodularinavarietyofcircuitapplications,withoutrequiringtheuseofpersonneltounderstanditsinternalstructure.Ifmusicintegratedsinglechip,seeminglysimplefunction,miniatureelectronicchipinthenet(theprincipleisdifferentfromthetapemachine),youneedacomputersimilartotheprincipleofthecomplex.Suchas:musicsignaltodigitalformstoredinmemory(likeROM),readbythemicrocontroller,analogmusicintoelectricalsignals(similartothesoundcard).

Inlargecircuits,modularapplicationsthatgreatlyreducethevolume,simplifiesthecircuitandreducethedamage,errorrate,butalsoeasytoreplace.

7.Microcontrollerintheapplicationfieldofautomotiveequipment

SCMinautomotiveelectronicsiswidelyused,suchasavehicleenginecontroller,CANbus-basedIntelligentElectronicControlEngine,GPSnavigationsystem,absanti-lockbrakingsystem,brakesystem,etc..

Inaddition,theMCUinbusiness,finance,research,education,nationaldefense,aerospaceandotherfieldshasaverywiderangeofapplications.Applicationofsiximportantpartoflearning

MCUlearninganimportantpartofthesixapplications

1,Bus:

Weknowthatacircuitisalwaysmadebythedevicesconnectedbywires,inanalogcircuits,theconnectiondoesnotbecomeaproblembecausethedeviceisaserialrelationshipbetweenthegeneral,thedeviceisnotmuchconnectionbetweenthe,butthecomputerisnotthesamecircuit,itisamicroprocessorcore,thedevicemustbeconnectedwiththemicroprocessor,thedevicemustbecoordinationbetween,sotheyneedtoconnectonalot,asifstillanalogcircuitlikethemicroprocessoranddevicesintheconnectionbetweentheindividual,thenumberoflineswillbealittlemoresurprising,thereforetheintroductionofthemicroprocessorbusZhongEachdeviceGongtongaccessconnections,alldevices8Shujulineallreceivedeightpubliconline,thatistheequivalentofalldevicestogetherinparallel,butonlythisdoesnotwork,iftherearetwodevicessenddataatthesametime,a0,a1,then,whetherthereceiverreceivedwhatisit?Thissituationisnotallowed,sotobecontrolledbycontrollingtheline,time-sharingthedevicetoworkatanytimeonlyonedevicetosenddata(whichcanhavemultipledevicestoreceiveboth).Device'sdataconnectionisknownasthedatabus,thedeviceiscalledlineofcontrolallthecontrolbus.Internalorexternalmemoryinthemicrocontrollerandotherdeviceshavememorycells,thememorycelltobeassignedaddresses,youcanuse,distribution,ofcourse,toaddressgivenintheformofelectricalsignals,andasmorememorycells,so,fortheaddressallocationThelineisalsomoreoftheselinesiscalledtheaddressbus.Second,data,address,command

Thereasonwhythesethreetogetherbecauseofthenatureofthesethreearethesame-thenumber,orareastringof'0'and'1'formthesequence.Inotherwords,addresses,instructionsarealsodata.Instruction:fromsinglechipdesignerprovidesanumberofcommonlyusedinstructionswithmnemonicwehaveastrictcorrespondencebetweenthedevelopercannotbechangedbytheMCU.Address:thesearchforMCUinternal,externalstorageunits,inputandoutputportbasedontheaddressoftheinternalunitvalueprovidedbythechipdesignerisgood,cannotbechanged,theexternalunitcanbesinglechipdeveloperstodecide,butthereareanumberofaddressunitsisamust(seeproceduresfortheimplementationoftheprocess).

Third,P0port,P2andP3ofthesecondfunctionIuse:

BeginnersoftenontheP0port,P2andP3portIusethesecondfunctionpuzzledthatthesecondfunctionandhaveaswitchbetweentheoriginalfunctionoftheprocess,orhaveadirective,infact,theportThesecondfeatureisautomatic,donotneedinstructionstoconvert.SuchasP3.6,P3.7respectivelyWR,RDsignal,whenthemicrochipprocessingmachinesexternalRAMorexternalI/Oport,theyareusedasasecondfunction,notasageneral-purposeI/Oportused,solongasaAmicroprocessorimplementationoftheMOVXinstruction,therewillbeacorrespondingsignalsentfromtheP3.6orP3.7,noprioruseofcommands.Infact'notasagen