Interconnect Delay Fault Test on Boards and SoCs with Multiple Clock Domains

This paper introduces an interconnect delay fault test (IDFT) controller on boards and system‐on‐chips (SoCs) with IEEE 1149.1 and IEEE 1500 wrappers. By capturing the transition signals launched during one system clock, interconnect delay faults operated by different system clocks can be simultaneously tested with our technique. The proposed IDFT technique does not require any modification on boundary scan cells. Instead, a small number of logic gates needs to be plugged around the test access port controller. The IDFT controller is compatible with the IEEE 1149.1 and IEEE 1500 standards. The superiority of our approach is verified by implementation of the controller with benchmark SoCs with IEEE 1500 wrapped cores.     

基于安全控制边界单元的IP核测试封装方法

为了解决测试信息传递的问题,IEEE组织推出了IEEE1500 IP(Intellectual Property)核测试封装标准以标准化口核测试接口.然而该标准给出的典型测试封装存在由测试数据扫描移人造成的不安全隐患.本文提出了一种基于安全控制边界单元的IP核测试封装方法.这种方法的核心思想是在典型的测试封装边界单元的...     

On IEEE P1500's Standard for Embedded Core Test

The increased usage of embedded pre-designed reusable cores necessitates a core-based test strategy, in which cores are tested as separate entities. IEEE P1500 Standard for Embedded Core Test (SECT) is a standard-under-development that aims at improving ease of reuse and facilitating interoperability with respect to the test of core-based system chips, especially if they contain cores from different sources. This paper briefly describes IEEE P1500, and illustrates through a simplified example its scalable wrapper architecture, its test information transfer model described in a standardized Core Test Language, and its two compliance levels. The standard is still under development, and this paper only reflects the view of six active participants of the standardization committee on its current status.     

一种基于嵌入式IP内核模块的测试方法

嵌入式内核结构的测试正面临着新的挑战,需要提出有效的测试方法。针对IP内核模块测试所面临的技术难点,详细介绍了IP核模块实现测试所需要构建的硬件环境和完整的测试方法,并分析了由测试理论和方法而形成的国际公认标准IEEEP1500。     

SoC的存储器Wrapper设计及故障测试

在系统芯片SoC测试中,存储器的可靠性测试是一项非常重要内容.IEEE Std 1500是专门针对嵌入式芯核测试所制定的国际标准,规范了IP核提供者和使用者之间的标准接口.基于此标准完成针对SoC存储器的Wrapper测试壳结构和控制器的设计.以32×8的SRAM为测试对象进行测试验证.结果表明,系统能够准确的诊断出存储器存在故障.     

系统芯片的可测性设计与测试

阐述了系统芯片(SoC)测试相比传统IC测试的困难,SoC可测性设计与测试结构模型,包括测试存取配置、芯核外测试层,以及测试激励源与测试响应汇聚及其配置特性、实现方法与学术研究进展,介绍了基于可复用内嵌芯核的SoC国际测试标准IEEE P1500的相关规约;最后,建议了在SoC可测性设计及测试中需要密切关注的几个理论问题。     

CAS-BUS: A Test Access Mechanism and a Toolbox Environment for Core-Based System Chip Testing

As System on a Chip (SoC) testing faces new challenges, some new test architectures must be developed. This paper describes a Test Access Mechanism (TAM) named CAS-BUS that solves some of the new problems the test industry has to deal with. This TAM is scalable, flexible and dynamically reconfigurable. The CAS-BUS architecture is compatible with the IEEE P1500 standard proposal in its current state of development, and is controlled by Boundary Scan features.This basic CAS-BUS architecture has been extended with two independent variants. The first extension has been designed in order to manage SoC made up with both wrapped cores and non wrapped cores with Boundray Scan features. The second deals with a test pin expansion method in order to solve the I/O bandwidth problem. The proposed solution is based on a new compression/decompression mechanism which provides significant results in case of non correlated test patterns processing. This solution avoids TAM performance degradation.These test architectures are based on the CAS-BUS TAM and allow trade-offs to optimize both test time and area overhead. A tool-box environment is provided, in order to automatically generate the needed component to build the chosen SoC test architecture.     

基于外壳架构与测试访问机制的数字芯核可测试性设计

深亚徽米技术的应用以及芯核的嵌入性特点.使传统的测试方法不再能满足芯核测试的需要.IEEEStdl 500针对此问题提出了芯核的可测试性设计方案——外壳架构和测试访问机制.基于IEEE Stdl 500.以74373与741 38软梭为例,提出数字芯梭可测试性设计的方法,并通过多种指令仿真验证了设计的合理性;设计的TAM控制器复用JTAC-端口,节约了测试端口资源.提供了测试效率.     

Design of reconfigurable access wrappers for embedded core based SoC test

Testing of embedded core based system-on-chip (SoC) ICs is a well known problem, and the upcoming IEEE P1500 Standard on Embedded Core Test (SECT) standard proposes DFT solutions to alleviate it. One of the proposals is to provide every core in the SoC with test access wrappers. Previous approaches to the problem of wrapper design have proposed static core wrappers, which are designed for a fixed test access mechanism (TAM) width. We present the first report of a design of reconfigurable core wrappers which allow for a dynamic change in the width of the TAM executing the core test. Analysis of the corresponding scheduling problem indicates that good approximate schedules can be achieved without significant computational effort. Specifically, we derive a O(N/sub C//sup 2/B) time algorithm which can compute near optimal SoC test schedules, where N/sub C/ is the number of cores and B is the number of top level TAMs. Experimental results on benchmark SoCs are presented which improve upon integer programming based methods, not only in the quality of the schedule, but also significantly reduce the computation time.     

Test-access mechanism optimization for core-based three-dimensional SOCs

Embedded cores in a core-based system-on-chip (SOC) are not easily accessible via chip I/O pins. Test-access mechanisms (TAMs) and test wrappers (e.g., the IEEE Standard 1500 wrapper) have been proposed for the testing of embedded cores in a core-based SOC in a modular fashion. We show that such a modular testing approach can also be used for emerging three-dimensional integrated circuits based on through-silicon vias (TSVs). Core-based SOCs based on 3D IC technology are being advocated as a means to continue technology scaling and overcome interconnect-related bottlenecks. We present an optimization technique for minimizing the post-bond test time for 3D core-based SOCs under constraints on the number of TSVs, the TAM bitwidth, and thermal limits. The proposed optimization method is based on a combination of integer linear programming, LP-relaxation, and randomized rounding. It considers the Test Bus and TestRail architectures, and incorporates wire-length constraints in test-access optimization. Simulation results are presented for the ITC 02 SOC Test Benchmarks and the test times are compared to that obtained when methods developed earlier for two-dimensional ICs are applied to 3D ICs. The test time dependence on various 3D parameters (e.g. 3D placement, the number of layers, thermal constraints, and the number of TSVs) is also studied.     

基于复用的SOC测试集成和IEEE P1500标准

以复用核测试为目标的测试策略是解决SOC测试问题的基础.IEEE P1500标准是国际上正在制订的嵌入式核测试标准,该标准旨在简化核测试信息的复用,提高SOC级测试集成的效率.文章介绍了截至目前为止P1500标准的制订情况,包括嵌入式核测试的体系结构、P1500的标准化目标,以及P1500的两级服从认证等.     

ALTECC_DECODER IP核的IEEE 1500 Wrapper设计

IP核的广泛应用提高了电路集成的效率。由于众多功能各异的IP核集成在电路中,完善的测试机制是确保其正常工作的前提。因此,如何对IP核进行测试成为复用IP核技术必须解决的问题。IEEE Std 1500提供了IP核的测试实现机制,文中基于IEEE 1500研究如何实现IP核的Wrapper设计,实验以Hamming码译码IP核ALTECC_DECODER为测试对象,验证了IEEE 1500 Wrapper可有效地对IP核进行测试。     

BIST for network on chip communication infrastructure based on combination of extended IEEE 1149.1 and IEEE 1500 standards

In this paper we propose a BIST based method to test network on chip (NOC) communication infrastructure. The proposed method utilizes an IEEE 1149.1 architecture based on BIST to at-speed test of crosstalk faults for inter-switch links as well as an IEEE 1500-compliant wrapper to test switches themselves in NOC communication infrastructure. The former architecture includes enhanced cells intended for MAF model test patterns generation and analysis test responses, and the later architecture includes: (a) a March decoder which decodes and executes March commands, which are scanned in serially from input system, on First-In-First-Out (FIFO) buffers in the switch; and (b) a scan chain which is defined to test routing logic block of the switch.To at-speed test inter-switch links one new instruction is used to control cells and TPG controller. Two new instructions, as well as, are applied to activate March decoder and to control scan activities in switch test session. These instructions are defined to fully comply with conventional IEEE 1149.1 and IEEE 1500 standards.     

Delay fault testing of IP-based designs via symbolic path modeling

Predesigned blocks called intellectual property (IP) cores are increasingly used for complex system-on-a-chip (SoC) designs. The implementation details of IP cores are often unknown or unavailable, so delay testing of such designs is difficult. We propose a method that can test paths traversing both IP cores and user-defined blocks, an increasingly important but little-studied problem. It models representative paths in IP circuits using an efficient form of binary decision diagram (BDD) and generates test vectors from the BDD model. We also present a partitioning technique, which reduces the BDD size by orders of magnitude and makes the proposed method practical for large designs. Experimental results are presented that show that it robustly tests selected paths without using extra logic and, at the same time, protects the intellectual contents of IP cores     

A BIST-based Solution for the Diagnosis of Embedded Memories Adopting Image Processing Techniques

This paper proposes a new solution for the diagnosis of faults into embedded RAMs, currently under evaluation within STMicroelectronics. The proposed scheme uses dedicated circuitry embedded in a BIST wrapper, and an ATE test program to schedule the data extraction flow and to analyze the gathered information. Testing is performed exploiting a standard IEEE 1149.1 TAP, which allows the access to multiple memory cores with a P1500 compliant solution. The approach aims at implementing a low-cost solution to diagnose embedded RAMs with the goal to minimize the ATE costs and the time required to extract the diagnostic information. In our approach, the ATE drives the diagnostic scheme and performs the classification of faults, allowing the adoption of low-cost equipments. The proposed solution allows a scalable extraction of test data, whose amount is proportional to the available testing time. In order to accelerate fault classification, image processing techniques have been applied. The Hough transform has been adopted to analyze the bitmap representing the faulty cells. Experimental results show the advantages of the proposed approach in terms of time required to complete the diagnostic process.     

改进格雷码条纹投影三维测量方法

传统的格雷码加相移法已经广泛应用于三维测量,但是相位解包裹一般需要投影多幅格雷码条纹,如何实现快速、准确的三维测量仍具有一定挑战性。提出了一种基于几何约束的改进格雷码条纹投影三维测量方法,可以有效减少格雷码条纹的数量。为了实现高速条纹投影,使用二值抖动技术将8位正弦相移条纹转换为1位二值图像。总共使用六幅条纹图像,其中三幅相移条纹用于计算截断相位,三幅格雷码条纹用于对截断相位进行初步展开获得伪展开相位,最后利用几何约束对伪展开相位进行解包裹获得绝对相位。实验结果表明,所提方法可以有效地重建被测物体的三维形貌。     

Enhancing Accuracy and Dynamic Range of Scientific Data Analytics by Implementing Posit Arithmetic on FPGA

The high performance, power efficiency and reconfigurable characteristic of FPGA attract more and more attention in big data processing. In scientific data analytics, besides the consideration of computing performance, accuracy of the results and dynamic range of data representation are critical features that must be considered. At present, the floating-point IP cores in FPGA design use IEEE standard for floating-point arithmetic – IEEE 754. For FPGA based scientific data application, improving existing floating-point IP cores is a significant way to obtain better results. Posit is a floating-point arithmetic format first proposed by John L. Gustafson in 2017. In posit, the variable precision and efficient representation of exponent contribute a higher accuracy and larger dynamic range than IEEE 754. This work researches on the FPGA implementation of posit arithmetic for extending floating-point IP cores for FPGA based scientific data analytics. We design the logic for hardware implementation and implement it on FPGA. We compare the precision representation, dynamic range and performance of implemented posit FPU (Floating-Point Unit) with IEEE 754 floating-point IP cores. Posit exhibits better superiority in precision representation and dynamic range than IEEE 754, and through further optimization of the implementation, posit can be a good candidate for floating-point IP cores.

     

基于模拟退火的全局相位展开算法

与常用的最小二乘和最小费用流相位展开算法求满足待求相位梯度与包裹相位梯度最小范数解不同,提出一种以待求相位的二阶相位差在整个相位场上的总和为目标函数,并利用模拟退火算法实现其最小化的相位展算法。计算表明：该算法可以对最小二乘和最小费用流算法不能展开的欠采样包裹相位和含有噪声的欠采样包裹相位,进行有效的相位展开。     

Noise-induced slope distortion in 2-D phase unwrapping by linearestimators with application to SAR interferometry

This paper explains the underestimation of phase slope and the consequent distortion of the phase surface, observed in two-dimensional (2-D) phase unwrapping by linear estimators, like least squares methods applied to synthetic aperture radar (SAR) interferometry. These methods minimize the difference between the gradient of the unwrapped phase and the wrapped differences of the measured wrapped phase. Using the probability distributions of phase noise and phase differences for a given coherence, the probability of a phase gradient error giving rise to a nonconservative vector field is derived. It is shown that this phase gradient error has nonzero mean in the presence of phase slopes. Linear phase estimators cannot distinguish the mean phase gradient error from a true phase slope; hence, the unwrapped phase shows a slope bias. This bias is quantified as a function of coherence and the number of independent samples that are averaged. The theoretical results are confirmed by simulations