Definition
Thecontrolunit,EnglishControlUnit(CU),isoneoftheCPUcomponents,sometimesinstalledoutsidetheCPU.Itsbasicfunctionistoaccessinstructionsfromwithin,analyzeinstructionsandexecuteinstructions.
Thecontrolunitisacontrolinstrumentorcontrolcomponentthatrealizesoneormorecontrollaws.Suchas:multiplexcontrolunit,proxysettingcontrolunit.
Type
Nomatterwhichtypeofcontrolunit,theprincipleistocontroleachpartoftheCPUthroughthecontrolsignalsentbythecontrolunit.Thecontrolunitcanberoughlydividedintothefollowingtwocategories.
Microprogram,whichreadsandsendsoutcontrolsignalsbymicroprogram.Themicroprogramisexecutedthroughasimpledigitalchannel(microcomputer)calledamicrosequencer.
Hardwarecontrolunit.Thecontrolsignalissentdirectlyfromthedigitalchannel.Duetothescaleofintegratedcircuitsandadvancesindesigntechnology,suchcontrolunitshavebecomepossible.
Function
Accordingtotheuser'spre-programmedprogram,itfetcheseachinstructionfromthememoryinturn,putsitintheinstructionregisterIR,andpassestheinstructionDecoding(analysis)determineswhatoperationshouldbeperformed,andthenthroughtheoperationcontrollerOC,accordingtothedeterminedtimesequence,themicro-operationcontrolsignalissenttothecorrespondingcomponent.TheoperationcontrollerOCmainlyincludescontrollogicsuchasabeatpulsegenerator,acontrolmatrix,aclockpulsegenerator,aresetcircuitandastart-stopcircuit.