The Design And Implementation Of Model Machine Based On The CPLD Combinational Logic

"The composition principle of computer"is a core course of computer professionalundergraduate course teaching,but also the study subject of postgraduate entranceexamination.The courses involved in many disciplines,supported by software,hardware,digital circuit and program design methodology course,etc.So it’s in a strong theoretical.Atthe same time it is a practical subject,and let the students to participate in the experimentcourse is a very effective way to learn this course.Therefore,the colleges and universitiesalso pay more and more attention to the course in the teaching experiment research.Themodel of machine used by the course experiment can be divided into combinational logiccontrol model machine and micro process control model according to the different methodsof control.In order to improve the quality of teaching and the composition principle of theexperiment,to master CPU internal structure and working principle,this topic was designedthe model machine controlled by combinational logic based on CPLD.The model machine designed based on the Von Neumann architecture.Bus structureusing8-bit single bus,and the mainly sections are instruction system,arithmetic logical unitmodule,memory module,combinational logic controller module.Instruction system designon the reduced instruction set (RISC) design thought,it mains by using high frequency ofarticle23function of instructions and three pane,and contains the register operationinstructions,memory access instructions,jump instructions and input and outputinstructions.Combinational logic controller designed on CPLD,divided into temporalrhythm,instruction decoder circuit and combinational logic circuit three parts.To completethe decoding by instructions decoder,to determine the machine cycle for10ticks formaking all orders can be completed in a cycle with the analysis of the instruction executionprocess.Analyzing the forming process of the control signal,listing the logical expressioncontrol signal,building up the combinational logic circuits,then combinational logiccontroller design completed at this time.Eventually form a model machine controlled bycombinational logic using Combinational logic controller, arithmetic logical unit andmemory.Controllers are implemented by CPLD,the advantage of model machine controlledby combinational in speed is more outstanding.It effectively enhances the flexibility toexperiment,improve the overall performance.It can meet students from the introduction toII further understand the working principle of the computer teaching requirements basically.