A Test Time Reduction Algorithm for Test Architecture Design for Core-Based System Chips

This paper deals with the design of SOC test architectures which are efficient with respect to required ATE vector memory depth and test application time. We advocate the usage of a TestRail Architecture, as this architecture, unlike others, allows not only for efficient core-internal testing, but also for efficient testing of the circuitry external to the cores. We present a novel heuristic algorithm that effectively optimizes the TestRail Architecture for a given SOC by efficiently determining the number of TestRails and their widths, the assignment of cores to the TestRails, and the wrapper design per core. Experimental results for four benchmark SOCs show that, compared to previously published algorithms, we obtain comparable or better test times at negligible compute time.     

Test Wrapper and Test Access Mechanism Co-Optimization for System-on-Chip

Test access mechanisms (TAMs) and test wrappers are integral parts of a system-on-chip (SOC) test architecture. Prior research has concentrated on only one aspect of the TAM/wrapper design problem at a time, i.e., either optimizing the TAMs for a set of pre-designed wrappers, or optimizing the wrapper for a given TAM width. In this paper, we address a more general problem, that of carrying out TAM design and wrapper optimization in conjunction. We present an efficient algorithm to construct wrappers that reduce the testing time for cores. Our wrapper design algorithm improves on earlier approaches by also reducing the TAM width required to achieve these lower testing times. We present new mathematical models for TAM optimization that use the core testing time values calculated by our wrapper design algorithm. We further present a new enumerative method for TAM optimization that reduces execution time significantly when the number of TAMs being designed is small. Experimental results are presented for an academic SOC as well as an industrial SOC.     

基于IP核的芯片级测试结构研究

分析了芯片级测试的特点以及与传统板级测试区别,对SOC测试结构的核心部分测试访问机制(TAM)和Wrapper进行了详细的论述,分析了系统级芯片的测试结构及其优化.     

A Graph-Based Approach to Power-Constrained SOC Test Scheduling

The test scheduling problem is one of the major issues in the test integration of system-on-chip (SOC), and a test schedule is usually influenced by the test access mechanism (TAM). In this paper we propose a graph-based approach to power-constrained test scheduling, with TAM assignment and test conflicts also considered. By mapping a test schedule to a subgraph of the test compatibility graph, an interval graph recognition method can be used to determine the order of the core tests. We then present a heuristic algorithm that can effectively assign TAM wires to the cores, given the test order. With the help of the tabu search method and the test compatibility graph, the proposed algorithm allows rapid exploration of the solution space. Experimental results for the ITC02 benchmarks show that short test length is achieved within reasonable computation time.     

A Reconfigurable Power Conscious Core Wrapper and its Application to System-on-Chip Test Scheduling

The increasing test application times required for testing system-on-chips (SOCs) is a problem that leads to higher costs. For modular core based SOCs it is possibly to employ a concurrent test scheme in order to lower the test application times. To allow each core to be tested as a separate unit, a wrapper is inserted for each core, the scan chains at each core are configured into a fixed number of wrapper chains, and the wrapper chains are connected to the test access mechanism. A problem with concurrent testing is that it leads to higher power consumption as several cores are active at a time. Power consumption above the specified limit of a core or above the limit of the system will cause damage and must be avoided. The power consumption must be controlled both at core level as well as on system level. In this paper, we propose a reconfigurable power conscious core wrapper that we include in a preemptive power constrained test scheduling algorithm. The advantages with the wrapper are that the number of wrapper chains at each core can dynamically be changed during test application and the possibility, through clock gating, to select the appropriate test power consumption for each core. The scheduling technique produces optimal solutions in respect to test time and selects wrapper configurations in a systematic manner while ensuring the power limits at core level and system level are not violated. The wrapper configurations are selected such that the number of wrapper configurations as well as the number of wrapper chains at each wrapper are minimized, which minimizes the wrapper logic as well as the total TAM routing. We have implemented the technique and the experimental results show the efficiency of our approach. The research is supported by the Swedish Foundation on Strategic Research (SFS) under the Strategic Integrated Electronic Systems Research (STRINGENT) program.     

A Note on System-on-Chip Test Scheduling Formulation

While many different formulations of the embedded core test scheduling problem (ECTSP) have been proposed in test literature recently, a single unified presentation of ECTSP in terms of conventional scheduling patterns has been lacking. There exists a large body of literature on multi-processor scheduling which can be directly applied to ECTSP; in this paper the author presents an introduction to scheduling notation and demonstrates the mapping between many important test scheduling problems like power-constrained, precedence constrained, and defect-oriented scheduling to conventional multi-processor job scheduling problems. Two examples are presented to illustrate this mapping. This unified presentation should make the existing body of knowledge in Operations Research scheduling research easily accessible to test engineers and test automation tool developers.     

Searching for Global Test Costs Optimization in Core-Based Systems

This paper proposes a comprehensive model for test planning and design space exploration in a core-based environment. The proposed approach relies on the reuse of available system resources for the definition of the test access mechanism, and for the optimization of several cost factors (area overhead, pin count, power constraints and test time). The use of an expanded test access model and its concurrent definition with the system test schedule makes it possible the search for a cost effective global solution. Experimental results over the ITC'02 SOC Test Benchmarks show the variety of trade-offs that can be explored using the proposed model, and its effectiveness on optimizing the system test planning.     

An Integrated Framework for the Design and Optimization of SOC Test Solutions

We propose an integrated framework for the design of SOC test solutions, which includes a set of algorithms for early design space exploration as well as extensive optimization for the final solution. The framework deals with test scheduling, test access mechanism design, test sets selection, and test resource placement. Our approach minimizes the test application time and the cost of the test access mechanism while considering constraints on tests and power consumption. The main feature of our approach is that it provides an integrated design environment to treat several different tasks at the same time, which were traditionally dealt with as separate problems. We have made an implementation of the proposed heuristic used for the early design space exploration and an implementation based on Simulated Annealing for the extensive optimization. Experiments on several benchmarks and industrial designs show the usefulness and efficiency of our approach.     

一种基于数据总􀀂 线的测试结构

复用数据总线作为测试传输机构的测试结构可以大大减小可测性设计的面积开销。因此，提出了一种针对该结构的测试包设计新方法：通过对测试包中与测试传输机构相连的测试包单元和相连的测试包单元分别设计，使前者设计成可寻址的测试数据缓冲器，从而构建了一种复用数据总线作为测试传输机构的新测试结构。由此让该结构具备了硬件开销小，测试过程控制简单，可实现并行测试的优点。     

基于TAM分组策略的SoC测试多目标优化设计

在片上系统芯片（System-on-Chip ,SoC）测试优化技术的研究中,测试时间和测试功耗是相互影响相互制约的两个因素。在基于测试访问机制（Test Access Mechanism ,TAM ）分组策略的基础上,以测试时间和测试功耗为目标建立了联合优化模型,运用多目标遗传算法对模型进行求解。以ITC’02标准电路中的p93791电路为实例进行验证,表明此方法能够在测试时间和测试功耗的优化上获得较理想的解,且能提高TAM通道的利用率。     

Test Scheduling of NoC‐Based SoCs Using Multiple Test Clocks

Network‐on‐chip (NoC) is an emerging design paradigm intended to cope with future systems‐on‐chips (SoCs) containing numerous built‐in cores. Since NoCs have some outstanding features regarding design complexity, timing, scalability, power dissipation and so on, widespread interest in this novel paradigm is likely to grow. The test strategy is a significant factor in the practicality and feasibility of NoC‐based SoCs. Among the existing test issues for NoC‐based SoCs, test access mechanism architecture and test scheduling particularly dominate the overall test performance. In this paper, we propose an efficient NoC‐based SoC test scheduling algorithm based on a rectangle packing approach used for current SoC tests. In order to adopt the rectangle packing solution, we designed specific methods and configurations for testing NoC‐based SoCs, such as test packet routing, test pattern generation, and absorption. Furthermore, we extended and improved the proposed algorithm using multiple test clocks. Experimental results using some ITC’02 benchmark circuits show that the proposed algorithm can reduce the overall test time by up to 55%, and 20% on average compared with previous works. In addition, the computation time of the algorithm is less than one second in most cases. Consequently, we expect the proposed scheduling algorithm to be a promising and competitive method for testing NoC‐based SoCs.     

半导体测试调度研究

半导体测试是资金高度密集、涉及产品种类与设备种类繁多的半导体生产环节.半导体测试需要同时使用测试机、送料机台和使能器等资源.资源组合及其可加工的产品类型的对应关系错综复杂,大多数半导体测试调度问题是考虑多资源约束和作业换型时间的平行机调度问题.分别从问题和方法两个角度对半导体测试调度研究进行分析,归纳了附加资源充足的测试调度和附加资源受限的测试调度两大类问题,并对目前半导体测试调度的各类方法进行总结对比,分析了各类方法的特点.     

基于BIST的编译码器IP核测试

介绍了用于IP核测试的内建自测试方法（BIST）和面向测试的IP核设计方法,指出基于IP核的系统芯片（SOC）的测试、验证以及相关性测试具有较大难度,传统的测试和验证方法均难以满足。以编译码器IP核为例,说明了基于BIST的编译码器IP核测试的基本实现原理和具体实现过程,通过加入测试外壳实现了对IP核的访问、隔离和控制,提高了IP核的可测性。     

On Concurrent Test of Core-Based SOC Design

In this paper, a method to solve the resource allocation and test scheduling problems together in order to achieve concurrent test for core-based System-On-Chip (SOC) designs is presented. The primary objective for concurrent SOC test is to reduce test application time under the constraints of SOC pins and peak power consumption. The methodology used in this paper is not limited to any specific Test Access Mechanism (TAM). Additionally, it can also be applied to SOC budgeting at design phase to predict a tradeoff between test application time and SOC pins needed. The contribution of this paper is the formulation of the problem as a well-known 2-dimensional bin-packing problem. A best-fit heuristic algorithm is adopted to achieve optimal solution.     

一种基于微处理器的SOC自测试方案

提出了一种基于片上微处理器和透明路径测试访问的SOC自测试方案。以片上微处理器为测试加载和响应收集比较的主体,构造透明路径并行传输测试数据,以嵌入程序控制测试过程。可以在提高测试速度的同时,降低对测试设备性能的依赖,并可以进行全速测试,所需额外面积开销较小。实验表明,该测试方案是有效的。     

IEEE Standard 1500 Compatible Oscillation Ring Test Methodology for Interconnect Delay and Crosstalk Detection

A novel oscillation ring (OR) test scheme and architecture for testing interconnects in SOC is proposed and demonstrated. In addition to stuck-at and open faults, this scheme can also detect delay faults and crosstalk glitches, which are otherwise very difficult to be tested under the traditional test schemes. IEEE Std. 1500 wrapper cells are modified to accommodate the test scheme. An efficient algorithm is proposed to construct ORs for SOC based on a graph model. Experimental results on MCNC benchmark circuits have been included to show the effectiveness of the algorithm. In all experiments, the scheme achieves 100% fault coverage with a small number of tests.     

SOC测试结构优化研究

结合SOC测试结构的特点,采用量子进化算法对SOC测试结构进行优化.通过对量子进化算法中群体尺寸、旋转角度的合适设定,达到减少SOC测试所用时间的目的.针对国际SOC标准电路验证表明,与同类算法相比,该算法能够获得较短的测试时间.     

一种改进的层次化SOCs并行测试封装扫描单元

 测试封装是实现SOC内部IP核可测性和可控性的关键,而扫描单元是测试封装最重要的组成部分.然而传统的测试封装扫描单元在应用于层次化SOCs测试时存在很多缺点,无法保证内部IP核的完全并行测试,并且在测试的安全性,功耗等方面表现出很大问题.本文提出一种改进的层次化SOCs测试封装扫描单元结构,能够有效解决上述问题,该结构的主要思想是对现有的扫描单元进行改进,实现并行测试的同时,通过在适当的位置增加一个传输门,阻止无序的数据在非测试时段进入IP核,使得IP核处于休眠状态,保证了测试的安全性,实现了测试时的低功耗.最后将这种方法应用在一个工业上的层次化SOCs,实验分析表明,改进的测试封装扫描单元比现有扫描单元在增加较小硬件开销的前提下,在并行测试、低功耗、测试安全性和测试覆盖率方面有着明显的优势.     

一种3D堆叠集成电路中间绑定测试时间优化方案

中间绑定测试能够更早地检测出3D堆叠集成电路绑定过程引入的缺陷,但导致测试时间和测试功耗剧增.考虑测试TSV、测试管脚和测试功耗等约束条件,采用整数线性规划方法在不同的堆叠布局下优化中间绑定测试时间.与仅考虑绑定后测试不同,考虑中间绑定测试时,菱形结构和倒金字塔结构比金字塔结构测试时间分别减少4.39%和40.72%,测试TSV增加11.84%和52.24%,测试管脚减少10.87%和7.25%.在测试功耗约束下,金字塔结构的测试时间增加10.07%,而菱形结构和倒金字塔结构测试时间只增加4.34%和2.65%.实验结果表明,菱形结构和倒金字塔结构比金字塔结构更具优势.     

On Using Exponential-Golomb Codes and Subexponential Codes for System-on-a-Chip Test Data Compression

We examine the use of exponential-Golomb codes and subexponential codes can be used for the compression of scan test data in core-based system-on-a-chip (SOC) designs. These codes are well-known in the data compression domain but their application to SOC testing has not been explored before. We show that these codes often provide slighly higher compression than alternative methods that have been proposed recently.