Verification And Simulation Model Of Dual Mode Nor Flash

Flash memory is a kind of non-volatile(Long-term preservation of its original data even under power failure)long-life memory,with its small size,large capacity,low power consumption,easy erasing,fast transmission speed,stable data storage and other advantages,it has attracted people's attention and favor in all aspects.At present,Nor Flash products have already covered all aspects of life,and products developed based on Nor Flash are constantly updated and iterated.Therefore,the research on Nor Flash model which integrates the verification model and simulation model,has great application value for the development of Nor Flash products or the products based on Nor Flash.This paper studies and designs a dual mode Nor Flash model.This model integrates the verification model and the simulation model,and it meets the functional requirements of data dual-mode transmission,identification of various Flash basic commands,command function implementation,timing check,and assertion check when making verification models.Based on the characteristics of Nor Flash,this paper analyzes the functional requirements of Nor Flash on the basis of the research about the working principles of Nor Flash,and divides the modules of Nor Flash model,including internal control module,address control module,status register module,protection module,memory module,timing check module and assertion verification module.In order to achieve the compatibility between the verification model and simulation model,this article employs the System Verilog language to design the Nor Flash model.The internal control module of the Nor Flash utilizes counters to achieve the correct input and output of data in different modes,and designs the working mechanism of different instructions;the assertion verification module applies SVA assertion technology to achieve internal timing check of the Nor Flash chip design and can quickly locate defects.Based on the right design and connection of each module,the dual-mode Nor Flash model is realized.This design not only realizes the compatibility and integration of the verification model and the simulation model,but also realizes the dual-mode data transmission of Nor Flash,identification of different instruction information,various work requirements,timing inspection,and assertion verification when making verification models,and lay a solid foundation for the subsequent verification work.After the Nor Flash model design is completed,UVM verification methodology is used for verification.First write the verification plan;then extract the functional verification points according to the design function;build a UVM verification platform that conforms to the characteristics of the Nor Flash model,add test cases for simulation;and finally analyze the simulation results.At the same time,collect functional coverage and code coverage,analyze coverage reports,and improve coverage.The final functional coverage reaches 100% and code coverage can reach 99.81%.The design and verification results show that the Nor Flash model designed this time can realize the integration of the verification model and the simulation model;it can correctly realize the dual-mode data transmission method;it can correctly identify different instructions and complete different functional operations;it can check the timing of the instruction format and reading and writing frequency;it can be used to verify the assertion of key signals in Nor Flash products during the verification model.Therefore,this design reached the expected goal.