Test System for Model Machine Based on MCS51

Principles of Computer Organization is the primary course of computer science, and thepractice teaching of the course attracts more and more attention in the universities. The originalmodel computer（abbreviated as "the model machine") experimental platform of our universityhas many drawbacks, such as unreasonable chip layout, plug wire confusion, not conducive totroubleshooting (and so on).For these reasons，our university redesign the model machine basedon the original experiment platform. Due to the experiment involves large logical scale andsophisticated overall wiring，the cause cannot be found in short time when the malfunctionappearing. Achieve automatic testing of the new model machine without plug wire is particularlyimportant.Model machine include five modules: memory module, arithmetic unit module, controllermodule, sequential module and auxiliary circuit. Through researching the model machineprinciples and functions,a model machine test scheme is proposed based on MCS51withreferencing the design principles of test system. The thought of designing test system utilizes thatMCS51series microcontroller system has the characteristic of embedded memory structure. Thetest program can be downloaded to the embedded memory of microcontroller based on thedesign principles of the test system. To test the hardware circuits of model machine’s memorymodules and calculation module and controller module as well as the other auxiliary circuits.Through analysising the modules functions and data access of model machine, a test hardwarearchitecture on model machine specially has been designed and the time-sharing multiplexingLord has been put forward. The main chip pin is assigned to each corresponding module test port,according to the model works and the data path of the module, from which control informationrequired for module testing and data information can be send to the model machine.The software design of the system is based on the hardware architecture through researchmodel machine and the functions of its modules.In order to design the needed testing functionchip and control signals, we need to research the function of the model machine’s each moduleto analysis the hardware circuit layout of specific module testing which is convenient fordiagnosising fault module and required for testing. What’s more the intuitive,simle and efficienttesting process can be designed after the analysis of the data path of each module and theconventional display device of model machine.Determine fault line by the analysis the conditions might arise that actual results do not match with the expected output data.This test system which associated auxiliary circuits can reach over90%has verifiedmultiple times and received very good results under the conditions of assurance of model Initialgood rates. It is convenient to detect model machine before the experiment for the non plug wiremodel machine.