IPOA组包功能的验证系统

介绍一种对IPOA应用中的组包功能进行RTL功能验证的系统。该验证系统可根据用户输入数据自动产生ATM信元作为激励 ,并对被测系统的输出进行自动验证。通过该验证系统大大提高了验证效率 ,缩短了仿真时间。同时 ,该系统产生的激励可对被测系统进行彻底的功能验证 ,提高了验证过程中代码覆盖率     

基于E语言的外部存储器接口的功能验证

在SoC设计中,传统功能验证方法已显示出其缺点,主要问题有：复杂验证场景难以构建;边缘情况难以覆盖。针对这些问题,业界提出了一种新的功能验证方法学——受限随机矢量生成的功能验证,该方法在满足约束条件的前提下,随机产生验证矢量。本文研究了受限随机矢量生成的功能验证在SoC设计中的应用,并以基于E语言和Specman验证平台验证了SoC芯片中的外部存储器接口,给出了具体的验证环境和验证步骤。验证结果表明,复杂验证场景和边缘情况的覆盖率均达到了100％。极大地提高了验证的效率和质量。     

Manipulation of Training Sets for Improving Data Mining Coverage-Driven Verification

The constant pressure for making functional verification more agile has led to the conception of coverage driven verification (CDV) techniques. CDV has been implemented in verification testbenches using supervised learning techniques to model the relationship between coverage events and stimuli generation, providing a feedback between them. One commonly used technique is the classification- or decision-tree data mining, which has shown to be appropriate due to the easy modeling. Learning techniques are applied in two steps: training and application. Training is made on one or more sets of examples, which relate datasets to pre-determined classes. Precision of results by applying the predictive learning concept has shown to be sensitive to the size of the training set and the amount of imbalance of associated classes, this last meaning the number of datasets associated to each class is very different from each other. This work presents experiments on the manipulation of data mining training sets, by changing the size and reducing the imbalances, in order to check their influence on the CDV efficiency. To do that, a circuit example with a large input space and strong class imbalance was selected from the application domain of multimedia systems and another one, with a small input space that affects the coverage occurrences, was selected from the communication area.     

On Design Validation Using Verification Technology

Despite great advances in the area of Formal Verification during the last ten years, simulation is currently the primary means for performing design verification. The definition of an accurate and pragmatic measure for the coverage achieved by a suite of simulation vectors and the related problem of coverage directed automatic test generation are of great importance. In this paper we introduce a new set of metrics, called the Event Sequence Coverage Metrics (ESCMs). Our approach is based on a simple and automatic method to extract the control flow of a circuit so that the resulting state space can be explored for validation coverage analysis and automatic test generation. During simulation we monitor, in addition to state and transition coverage, whether certain control event sequences take place or not. We then combine formal verification techniques, using BDDs as the underlying representation, with traditional ATPG and behavioral test generation techniques to automatically generate additional sequences which traverse uncovered parts of the control state graph, or exercise an uninstantiated control event sequence.     

RFID标签芯片验证平台

RFID(Radio Frequency Identification)标签芯片命令及其帧格式多样,增加了验证的复杂性,而且验证充分性难以得到保障.为了能够高效地验证RFID标签芯片以及解决验证充分性的问题,提出了一种基于覆盖率和受约束的随机激励的面向对象的功能验证平台设计方法.验证平台不仅能对单条命令进行验证,也能对特定的和随机的命令流进行验证,并自动检查验证结果.实践表明,该验证平台大大提高了验证生产率,保证了流片后芯片功能的正确性.     

Automatic Vector Generation Using Constraints and Biasing

Constraining and biasing are frequently used techniques to enhance the quality of randomized vector generation. In this paper, we present a novel method that combines constraints and input biasing in automatic bit-vector generation for block-level functional verification of digital designs, which is implemented in a tool called SimGen. Vector generation in SimGen is confined to a legal input space that is defined by constraints symbolically represented in Binary Decision Diagrams (BDDs). A constraint involving state variables in the design defines a state-dependent legal input space. Input biasing can also depend on the state of the design. The effect of constraints and input biasing are combined to form what we called the constrained probabilities of input vectors. An algorithm is developed to efficiently generate input vectors on-the-fly during simulation. The vector generation is a one-pass process, i.e., no backtracking or retry is needed. Also, we describe methods of minimizing the constraint BDDs in an effort to reduce the simulation-time overhead of SimGen. Furthermore we discuss the application of SimGen to a set of commercial design blocks.     

基于VMM统一验证平台的处理器芯片功能验证

本文结合处理器芯片实际项目,重点介绍了功能验证环节的工作。文章基于VMM验证平台,利用System Verilog语言自动生成测试激励,采用断言和功能覆盖率相结合的验证方法,实时监测RTL模型运行时的各种信号,自动进行覆盖率统计,通过增加约束实现覆盖率的快速收敛。文章最终给出了基于VMM验证平台进行功能验证的结果,绘制了功能覆盖率上升曲线。     

A Biased Random Instruction Generation Environment for Architectural Verification of Pipelined Processors

Architectural verification is a critical aspect of the microprocessor design cycle. In this paper, we present a design verification environment centered around a biased random instruction generator for simulation-based architectural verification of pipelined microprocessors. The instruction generator uses biases specified by the user to generate instruction sequences for simulation. These biases are not hard-coded and can thus be changed depending on the specific areas in the design and type of design errors being targeted. Correctness checking is achieved using assertion checking and end-of-state comparison with a high-level architectural model. Several architectural-level errors are introduced into a behavioral model of the DLX processor to investigate the processor's response in the presence of design errors. Simulation experiments conducted using the behavioral model show that biased random instruction sequences provide higher coverage of RTL conditional branches and design errors than random instruction sequences or manually-generated test programs. Furthermore, instruction sequences containing a high percentage of read-after-write (RAW) and control dependencies are the most useful.     

BUSpec: A framework for generation of verification aids for standard bus protocol specifications

A typical verification intellectual property (VIP) of a bus protocol such as ARM advanced micro-controller bus architecture (AMBA) or PCI consists of a set of assertions and associated verification aids such as test-benches, design-ware models and coverage metrics. While several languages have been formalized for specifying assertions (examples include Open-Vera Assertions, Sugar, ForSpec, System Verilog Assertions, etc.), it is widely accepted that the tasks of writing protocol-compliant models and test-benches that produce protocol compliant stimuli are also tasks of equal importance. In this paper, we present a platform for high-level specification of a bus protocol in a hierarchical manner and an automated methodology for generating a variety of verification aids that supplement the set of assertions in a VIP. We also show that the verification aids can be efficiently used to determine the completeness of the set of assertions in a simulation-based verification environment.     

一种高效高速的大容量FPGA电路功能验证方法

对大容量FPGA芯片进行功能验证时,如何提高验证效率以及验证用例的覆盖率已经成为缩短总体产品时间所面临的挑战.针对上述问题,提出了一种高效、高速的大容量FPGA电路验证方法,可以根据验证用例需求,利用FPGA预先配置一定的功能,通过采取不同的配置文件得到最优网表.该验证方法具有灵活动态配置网表功能,可以节省仿真资源80％左右,大幅度缩短仿真时间,仿真器运行速度至少提高20倍,同时可以提高验证效率,最大限度地提高验证电路的覆盖率,能够满足大容量电路功能仿真的需求.该验证方法已成功应用于大容量FPGA电路功能验证工程实践中.     

Automatic Verification Stimulus Generation for Interface Protocols Modeled With Non-Deterministic Extended FSM

Verifying if an integrated component is compliant with certain interface protocol is a vital issue in component-based system-on-a-chip (SoC) designs. For simulation-based verification, generating massive constrained simulation stimuli is becoming crucial to achieve a high verification quality. To further improve the quality, stimulus biasing techniques are often used to guide the simulation to hit design corners. In this paper, we model the interface protocol with the non-deterministic extended finite-state machine (NEFSM), and then propose an automatic stimulus generation approach based on it. This approach is capable of providing numerous biasing strategies. Experiment results demonstrate the high controllability and efficiency of our stimulus generation scheme.     

基于UVM的PCI Express总线控制器验证平台

针对高速外设部件互连(Peripheral Component Interconnect Express,PCIe)总线控制器数据格式复杂、链路状态繁多的特点,提出了基于System Verilog语言的通用验证方法学(Universal Verification Methodology,UVM)验证平台。相较于传统定向验证方法,该验证平台中的验证用例使用受约束的随机方式对PCIe模块进行充分验证,能自动进行结果比对,并在回归测试中自动收集覆盖率数据。结果表明,该验证平台可以快速定位设计缺陷,在兼顾较好的可重用性和可配置性的同时,实现覆盖率验证目标,大大提高验证效率。     

Enhancing IP cores specifications using hierarchical composition and set theory

During the functional verification, complex interactions between multiple blocks that compose an Intellectual Property (IP) core can reveal hard-to-find bugs. Functional verification specifications must be precise to assure these interactions occur during the simulation. In this work, we are proposing a technique for improving the functional verification specification of individual blocks, preserving the occurrence of these interaction scenarios in the composition phase. Our approach was implemented for the VeriSC methodology, a SystemC-based functional verification methodology. After each block that composes the IP core was stand-alone verified, we exploit the composition phase using set theory to increase the coverage numbers and to justify why some of these numbers cannot, or need not, reach 100%. By applying our approach in a MPEG 4 video decoder design, we show how our work can save functional verification time during the hierarchical composition. Using mutation based-tests, we demonstrate that our work can contribute to error detection. Furthermore, we demonstrate the effectiveness of our approach with regard to traditional structural coverage metrics, such as line coverage and branch coverage.     

基于受限随机矢量生成的功能验证

在SOC设计中,传统功能验证方法面临诸多挑战,主要体现在：①复杂验证场景难以构建。②边缘情况难以覆盖。基于受限随机矢量生成的功能验证方法在满足约束条件的前提下,随机产生验证矢量．有效解决了传统验证方法面临的挑战。本文以一款SOC的存储子系统控制模块为例,研究了在Specman验证平台上,使用E语言构建验证环境的基于受限随机矢量生成的功能验证在SOC设计中的应用。验证结果表明,复杂验证场景和边缘情况的覆盖率均达到100％。经过多目标圆片(MPW)流片试验和测试,采用该方法验证的模块达到设计要求。     

An Automatic Functional Coverage for Digital Systems Through a Binary Particle Swarm Optimization Algorithm with a Reinitialization Mechanism

At present, functional verification represents the most expensive part of the digital systems design. Moreover, different problems such as: clock synchronization, code compatibility, simulation automation, new design methodologies, proper use of coverage metrics, among others represent challenges in this area. The automated test vector generation is involved in these problems. In this work, an automated functional test sequences generation for digital systems based on the use of coverage models and a binary Particle Swarm Optimization algorithm with a reinitialization mechanism (BPSOr) is described. Also, a comparison with other meta-heuristic algorithms such as: Genetic algorithms (GA) and pseudo-random generation is presented using different fitness functions, coverage models and devices under verification. The main strategy is based on the combination of the simulation and meta-heuristic algorithms to test the device behavior through the generation of test vector sequences. According to the results, the proposed test generation method represents a good alternative to increase the functional coverage during the automated functional verification of block-level digital systems verification.     

An analog behavioral equivalence boundary search methodology for simulink models and circuit level designs utilizing evolutionary computation

We propose a simulation-based analog equivalence boundary search methodology for high level Simulink models and their low level HSpice counterparts.The equivalence of high and low level designs is determined by comparing a set of predefined performance parameters measured during the simulation of both models. Our methodology investigates the search space to obtain boundary of input parameters, where both models have equivalent performance parameters. We build an optimization problem, where the error percentage between the performance parameters of both models being less than a specified threshold is defined as success criteria. In this problem, input parameters are determined by utilizing evolutionary computation. At the end of the optimization, the border of equivalence for the models is found for input parameters satisfying the success criteria. We demonstrate the validity of our approach on three designs, an inverter, an operational amplifier, and a buck converter, where our approach proves to be an efficient tool in finding an equivalence boundary of analog circuits and models.     

一种可重构的通用总线接口验证平台的研究及实现

以UART总线接口为例介绍一种高性能验证平台.该验证平台基于SystemVerilog语言,以功能覆盖率为导向,通过带约束的随机方法产生测试激励,并具有自动检查运行结果及可重用性等特点.实践表明,与传统的验证平台相比,该平台在验证效率及功能覆盖率方面均有明显的优越性;与基于VMM搭建的验证平台相比,该平台也表现出了一定...     

Real-time automated register abstraction active power-aware electronic system level verification framework

All modern low power system on a chip (SoC) architectures are equipped with an in-built power management system. Every new system is expected to have more features and lower power consumption, resulting in a continuous demand to improve energy efficiency. To cope up with the ever increasing demand, an active power-aware management verification architecture is necessary to minimize the power consumption. Power reduction techniques include clock-gating, power-gating, multi-voltage, and voltage-frequency scaling. The proposed verification architecture utilizes the Unified Power Format (UPF) 2.1 libraries to achieve early design verification at the Electronic System-Level (ESL) of abstraction. The proposed testbench can verify several designs of different power management schemes. The presented work offers a reduction in power states, CPU time and simulation time as compared to existing techniques. The interactive formal and simulation-based verification methods are used in this paper to remove the simulation artifacts during functional and power co-simulation. Additionally, this paper incorporates functional correctness and power-aware checks for different modules of Design Under Verification (DUV) at Transaction-Level Modeling (TLM).     

IP最小参数空间提取模型

为了能使IP在不同的系统中被重用,通常将IP参数化.参数的广泛使用一方面给IP重用带来方便,另一方面大量的参数又将给IP认证、验证和集成带来新的问题.针对IP参数化带来的问题提出一种新的递交方法,首先基于参数及其相互依赖关系,对大量的参数进行统一描述,再构成参数域值图PDG将参数空间分为多个正交的有效予空间.依靠PDG,用户进行参数检查所需要的测试向量条件可以自动产生,而且也可以获取验证环境的约束条件,收集、分析功能覆盖率的数据,减少了系统设计过程中的验证工作.