Design Of Verification Platform For Vehicle MCU Based On UVM

Along with the rapid growth of in-vehicle data processing,the in-vehicle micro-control unit(MCU)has gradually evolved into a low-power,high-computing and highly integrated system on chip.The stringent requirements of the in-vehicle MCU for computing power pose a great challenge to the verification work.This thesis combines the author's project in the internship company to study the sub-modules and system functions of the vehicle MCU.Based on the extracted module-level and system-level functional verification points,the module-level and system-level verification schemes are designed and the functional coverage model is designed.Finally,a module-level and system-level verification platform was built based on the UVM verification methodology,and the functional verification of each sub-module and system of the vehicle MCU was completed.There are many in-vehicle MCU modules,and the functional verification process is complicated.In order to speed up the convergence rate of coverage and improve the verification efficiency,this thesis adopts the design principle of Top-Down.Firstly,according to the structural characteristics of the in-vehicle MCU,AHB_UVC and APB_UVC are designed to emulate the behaviors of registers configuration by AHB and APB bus master.PWT_UVC,MSCAN_UVC,UART_UVC and other universal verification component generates input excitations for modules such as PWT,MSCAN,and UART,collects the response behavior of each module,and judges the correctness of response behavior.Then,each UVC structure is carefully divided,and the UVC is divided into an excitation generating unit,an interaction unit,a comparator,an environment component,and a coverage rate collecting unit.The excitation generating unit generates limited random excitations such as apb_trans and can_trans;the interaction unit drives input signals of modules such as PWT,MSCAN,and I2 C,and monitors the behavior of signals in the input and output interfaces of each module in real time;the comparators judges the response behavior of the PWT,MSCAN,I2 C and other modules;the environment component is encapsulated with the underlying verification component to achieve integration of the component to a higher level;the coverage collection unit such as ahb_cov,pwt_cov is used to collect coverage information of the on-chip bus behavior and module interface behavior.Based on the coverage information,the random constraint domain is narrowed and a directed test case is applied.In order to verify the timing in the interface,an assertion is designed to check whether the signal timing in the interfaces such as apb_if or ahb_if conforms to the specification.Finally,based on the design verification platform,the verification platform is optimized to improve the verification completeness.The clock behavior of frequency is changed to simulate the frequency change of the MCU in actual operation.The gray box verification method is introduced to verify the counter module such as PWT,and the callback method is introduced to optimize the multiplexing form of the verification component.This thesis evaluates the verification work through the simulation results and coverage report of the test case.The coverage report is divided into code coverage report,function coverage report and assertion coverage report.Analyze the code and function points not covered in the verification and add direct test cases.The final code coverage rate is 95.65%,the function coverage rate is 100%,and the assertion coverage rate is 100%.In the verification process,the relationship between the number of test cases and the coverage rate is collected.After comparison and analysis,the in-vehicle MCU verification platform UVM-based constructed in this thesis is superior to the traditional verification platform C-based in terms of the maintainability of the verification platform and the contribution of the verification platform to the coverage rate.