Functional Safety Verification Of RISC Processor Based On ISO26262

With the development of automotive electronics,in order to ensure the safety of car driving,functional safety verification becomes more and more important.Functional safety verification is a brand-new research field,and its purpose is to verify the effectiveness of the chip safety mechanism.At present,there are very few domestic and foreign manufacturers that can perform functional safety verification on chips.Synopsys has accumulated strong technology in this direction due to its early start.Based on the ISO26262 safety standard and Z01 X tool,this paper uses the functional safety verification idea to design a functional safety verification platform.On this basis,the functional safety verification of the RISC processor(automotive electronics)is carried out.The RISC processor is equipped with the safety mechanisms necessary for critical safety applications,although the safety mechanism increases the area of the processor,it improves the advantage of the processor in terms of functional safety.The main work of this paper is as follows:1)The safety mechanism of the RISC processor is studied.The safety mechanism configured by the RISC processor includes: the ECC module protects the correctness and consistency of the data while the program is running;the Watchdog Timer module is used to detect time-based errors;the Memory Protection Unit protects system resources and tasks from illegal access;Lockstep technology can detect the fault of the processor core due to radiation and other factors;the Safety Monitor module is responsible for monitoring and reporting various errors of the processor core,bus,and itself.The safety mechanism can effectively detect the related faults generated by the RISC processor and ensure the correct operation of the processor.Based on this principle,this paper verifies the effectiveness of the RISC processor’s safety mechanism.2)Based on the industry’s most advanced functional safety verification fault simulation tool Z01 X,the functional safety verification platform is designed.The main work is to carry out detailed design for the modules such as observation point setting,excitation mode selection,fault state setting,fault location setting,fault simulation variable setting,and coverage ratio definition of the functional safety verification platform.After continuous practice and improvement of multiple functional safety verification projects of Synopsys,the platform has become a very complete,accurate and effective functional safety verification platform,which plays an increasingly important role in the functional safety verification process of the chip.3)The types of faults that Z01 X tool can inject are stuck at and transient faults.These two types of faults can cover most of the faults in practical applications.Based on the functional safety verification platform,the Z01 X injects stuck at and transient faults into the RISC processor with and without safety mechanism protection.Then compile,logic simulation,and fault simulation of the above design,and the results of the compilation and logic simulation are correct,which proves the correctness of the design logic,and subsequent fault simulation can be carried out.4)Based on the ISO26262 safety standard,the fault simulation results are analyzed.First,by comparing and analyzing the fault simulation results of the RISC processor with and without safety mechanism protection,it is found that the former has higher fault coverage and stronger fault detection capability.For RISC processors protected by a safety mechanism,the fault coverage rates of the two fault types stuck at and transient can reach 98.27% and 98.63%.The coverage results meet the ASIL C(≥97%)standard specified in the ISO26262 standard.And the fault coverage rate of the RISC processor is 8% points higher than the ASIL B standard followed by most products on the market,which is very meaningful for the research of chip functional safety verification.In summary,based on the ISO26262 standard and Z01 X tool,this paper introduces the functional safety verification idea,analyzes the safety mechanism of the RISC processor,designs a functional safety verification platform,and performs functional safety verification on the RISC processor.The fault simulation results show that the safety mechanism of the RISC processor meets the ASIL C standard specified in ISO26262,which proves that the safety mechanism of the RISC processor is effective.