Constructing IP cores’ transparency paths for SoC test access using greedy search

Today’s SoC design demands efficient test access mechanism to develop and perform manufacturing test. Transparency based methods have their advantages for IP cores’ test reuse in SoC level. In this paper, an IP core transparency paths construction approach employing greedy search strategy based on gate-level heuristic information is proposed. With these transparency paths, IP cores can consecutively transfer one test per clock cycle from their inputs to outputs, and thus can be used in transparency-based test scheme to benefit at-speed testing and decrease the demand of parallel TAMs. The experimental results show lower extra overhead needed in our approach than conventional boundary scan and previous RT level approaches.     

MICRO: a new hybrid test data compression/decompression scheme

To overcome the limitation of the automatic test equipment (ATE), test data compression/decompression schemes become a more important issue of testing for a system-on-chip (SoC). In order to alleviate the limitation of previous works, a new hybrid test data compression/decompression scheme for an SoC is developed. The new scheme is based on analyzing the factors that influence test parameters: compression ratio and hardware overhead. To improve compression ratio, the proposed scheme, called the Modified Input reduction and CompRessing One block (MICRO), uses the modified input reduction, the one block compression, a novel mapping, and reordering algorithms. Unlike previous approaches using the cyclic scan register architecture, the proposed scheme is to compress original test data and to decompress the compressed test data without the cyclic scan register architecture. Therefore, the proposed scheme leads to high-compression ratio with low-hardware overhead. Experimental results on ISCAS '89 and ITC '99 benchmark circuits prove the efficiency of the new method.     

一种复杂SoC可测性的设计与实现

随着SoC的复杂度和规模的不断增长,SoC的测试变得越来越困难和重要.针对某复杂32-bit RISC SoC,提出了一 种系统级DFT设计策略和方案.在该方案中,运用了多种不同测试设计方法,包括内部扫描插入、存储器内建自测试、边界扫描和功能测试矢量复用.结果显示,该策略能取得较高的测试覆盖率和较低的测试代价.     

降低系统芯片中跨时钟域设计和验证复杂度的方法

在系统芯片设计中,直接采用现有的跨时钟域信号处理方法不仅设计复杂度高而且验证难度大.为了解决这个问题,将跨时钟域设计与功能设计完全分离,在每个通信接口部件中采用独立的、专用的跨时钟域处理模块统一解决跨时钟域信号的传输问题,并通过封装点对点通信接口和合并处理同一方向的跨时钟域信号,将需要处理的跨时钟域信号的数量减少为方向相反的2组.实验结果表明,该方法能够有效降低跨时钟域设计的验证难度和系统芯片的设计复杂度,并且不会明显增加功能部件的传输延迟和面积开销.     

基于FDR码改进分组的SoC测试数据压缩方法

文章提出一种基于FDR码改进分组的SoC测试数据压缩方法.经过对原始测试集无关位的简单预处理,提高确定位0在游程中的出现频率.在FDR码的基础上,改进其分组方式,通过理论证明其压缩率略高于FDR编码,尤其是短游程的压缩率.用C语言编写程序模拟两种编码方法的软件实现程序,实验结果证明了改进分组的FDR编码方法的有效性和高压缩性.     

Test data compression using alternating variable run-length code

This paper presents a unified test data compression approach, which simultaneously reduces test data volume, scan power consumption and test application time for a system-on-a-chip (SoC). The proposed approach is based on the use of alternating variable run-length (AVR) codes for test data compression. A formal analysis of scan power consumption and test application time is presented. The analysis showed that a careful mapping of the don’t-cares in pre-computed test sets to 1s and 0s led to significant savings in peak and average power consumption, without requiring slower scan clocks. The proposed technique also reduced testing time compared to a conventional scan-based scheme. The alternating variable run-length codes can efficiently compress the data streams that are composed of both runs 0s and 1s. The decompression architecture was also presented in this paper. Experimental results for ISCAS'89 benchmark circuits and a production circuit showed that the proposed approach greatly reduced test data volume and scan power consumption for all cases.     

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.     

一种新型低峰值功耗的BIST设计研究

随着手持设备的兴起和芯片对晶片测试的要求越来越高,内建自测试的功耗问题引起了越来越多人的关注。文章对目前内建自测试的可测性设计技术进行了分析,并提出了折叠种子优化降低节点峰值功耗的模型,通过调整种子结构和测试向量的相关性的办法来避免过高的SoC测试峰值功耗。采取了屏蔽无效测试模式生成、提高应用测试向量之间的相关性以及并行加载向量等综合手段来控制测试应用,使得测试时测试向量的输入跳变显著降低,从而大幅度降低节点的峰值功耗。实验结果表明,该方案可以有效地避免BIST并行执行可能带来的过高峰值功耗。     

Iteration-free fractal image coding based on efficient domain pooldesign

The domain pool design is one of the dominant issues which affect the coding performance of fractal image compression. In this paper, we employ the LBG algorithm and propose a block averaging method to design the efficient domain pools based on a proposed iteration-free fractal image codec. The redundancies between the generated domain blocks are reduced by the proposed methods. Therefore, we can obtain the domain pools that are more efficient than those in the conventional fractal coding schemes and thus the coding performance is improved. On the other hand, the iteration process in the conventional fractal coding scheme not only requires a large size of memory and a high computation complexity but also prolongs the decoding process. The proposed iteration-free fractal codec can overcome the problems above. In computer simulation, both the LBG-based and block-averaging methods for the domain pool design in the proposed iteration free scheme achieve excellent performances. For example, based on the proposed block-averaging method, the decoded Lena image has at least a 0.5 dB higher PSNR (under the same bit rate) and an eight-time faster decoding speed than the conventional fractal coding schemes that require iterations.     

基于TSV绑定的三维芯片测试优化策略

本文提出一种三维片上系统(3D SoC)的测试策略,针对硅通孔(TSV,Through Silicon Vias)互连技术的3D SoC绑定中和绑定后的测试进行优化,由于测试时间和用于测试的TSV数目都会对最终的测试成本产生很大的影响,本文的优化策略在有效降低测试时间的同时,还可以控制测试用的TSV数目,从而降低了测试成本.实验结果表明,本文的测试优化策略与同类仅考虑降低测试时间的策略相比,可以进一步降低约20%的测试成本.     

Region-of-interest image coding based on EBCOT

In this paper, an efficient, region-of-interest (ROI) coding scheme achieved by modifying the implicit ROI encoding method is proposed. This new method reduces the priority of background coefficients in the ROI code-block without compromising algorithm complexity. It is suitable for applications in which it may be desirable to encode the ROI to a higher quality level than the background. In addition, several EBCOT-based ROI coding schemes for image compression are discussed. Experimental results demonstrate that the proposed ROI coding scheme improves the compression efficiency and combines the advantages of the implicit ROI encoding method (low complexity) and the maxshift method (good ROI rate distortion performance).     

多电源混合电压SoC的全芯片ESD设计实例

SoC是含有微处理器、外围电路等的超大规模集成电路,具有器件特征尺寸小、复杂度高、面积大、数模混合等特点,SoC的ESD设计成为设计师面临的一个新的设计挑战。文章详细介绍了一个复杂的多电源、混合电压专用SoC芯片的全芯片ESD设计方案,并结合电路特点仔细分析了SoC芯片ESD设计的难点,提出了先工艺、再器件、再电路三个层次的分析思路,并将芯片ESD总体解决方案中的关键设计重点进行了逐一分析,最后给出了全芯片ESD防护架构的示意图。该SoC芯片基于0.35μm 2P4M Polycide混合信号CMOS工艺流片,采用文中提出的全芯片ESD防护架构,使该芯片的HBM ESD等级达到了4kV。     

一种混合信号SoC中模数转换器的内建自测试方案

提出了一种针对混合信号SoC中ADC的动态参数与静态参数测试的内建自测试方案.由于动态参数和静态参数在同一个测试电路中都能够得到测试,因此能够更加全面准确地反映待测器件的性能.通过对存储器和计算资源的合理配置和复用,将两种测试的激励产生和响应分析集成在一起,最大程度地减少了对电路面积的影响.整个设计在FPGA上实现,实验结果证明了其可行性.     

Test response reuse-based SoC core test compression and test scheduling for test application time minimization

This paper presents a novel approach to system-on-a-chip (SoC) core test compression and test scheduling. Every test set is compressed through the test responses of its preceding core in preprocessing step by simulation. Consequently, under our method the test sets contain two parts: (1) the test sets that are compatible with the test responses of their individual preceding cores. This part can be removed from their original test sets, and (2) the test sets that none of the test vectors from them are compatible with the test responses of their individual preceding cores. On hardware implementation, only a couple of 2-1 MUXs are needed. The algorithms for reordering the sequences of core-under-tests and those of the test vectors for each corresponding core are outlined for optimal test compression results. It needs neither coder nor decoder, thus saving hardware overhead. Power-constrained SoC core test pipelining consumes less test application time. Hierarchical clustering-based SoC test scheduling can be implemented easily, and the hardware overhead is negligible. Experimental results on benchmark ISCAS 89 demonstrate that our method achieves significant improvement of test time and less ATE requirement over the previous methods, and it does not discount the fault coverage of each test set, moreover, the fault coverage for some test sets is improved instead.     

SoC interconnection protection through formal verification

The wide adoption of third-party hardware Intellectual Property (IP) cores including those from untrusted vendors have raised security concerns for system designers and end-users. Existing approaches to ensure the trustworthiness of individual IPs rarely consider the entire SoC design, especially the IP interactions through SoC bus. These methods can hardly identify malicious logic (or design flaws) distributed in multiple IPs whereas individual IPs fulfill security properties and can pass the security testing/verification. One possible solution is to treat the SoC as one IP core and try to verify security properties of the entire design. This method, however, suffers from scalability issues due to the large size of SoC designs with multiple IP cores integrated. In this paper, we present a scalable SoC bus verification framework trying to verify the security properties of SoC bus implementation where the bus protocol plays the role of the golden reference. More specifically, finite state machine (FSM) models will be constructed from the bus implementation and the trustworthiness will be verified based on the property set derived from the bus protocol and potential security threats. Along with IP level formal verification solutions, the proposed framework can help ensure the security of large-scale SoCs. Experimental results on ARM AMBA Bus demonstrate that our approach is applicable and scalable to prevent information leakage and denial-of-service (DoS) attack by verifying security properties.     

一种有效的双矢量测试BIST实现方案

文章提出了一种简单有效的双矢量测试BIST。实现方案．其硬件主要由反馈网络可编程且种子可重置的LF—SR和映射逻辑两部分构成。给出了一种全新的LPSR最优种子及其反馈多项式组合求取算法，该算法具有计算简单且容易实现的特点。最后。使用这种BIST、方案实现了SoC中互联总线间串扰故障的激励检测，证明了该方案在计算量和硬件开销方面的优越性。     

基于V93000的SoC中端口非测试复用的ADC和DAC IP核性能测试方案

 SoC(System-on-a-Chip)芯片设计中,由于芯片测试引脚数目的限制以及基于芯片性能的考虑,通常有一些端口不能进行测试复用的IP(Intellectual Property)核将不可避免地被集成在SoC芯片当中.对于端口非测试复用IP核,由于其端口不能被直接连接到ATE(Automatic Test Equipment)设备的测试通道上,由此,对端口非测试复用IP核的测试将是对SoC芯片进行测试的一个重要挑战.在本文当中,我们分别提出了一种基于V93000测试仪对端口非测试复用ADC(Analog-to-Digital Converter)以及DAC(Digital-to-Analog Converter)IP核的性能参数测试方法.对于端口非测试复用ADC和DAC IP核,首先分别为他们开发测试程序并利用V93000通过SoC芯片的EMIF(External Memory Interface)总线对其进行配置.在对ADC和DAC IP 核进行配置以后,就可以通过V93000捕获ADC IP 核采样得到的数字代码以及通过V93000 采样DAC IP 核转换得到的模拟电压值,并由此计算ADC以及DAC IP 核的性能参数.实验结果表明,本文分别提出的针对端口非测试复用ADC以及DAC IP 核测试方案非常有效.     

LFSR Reseeding-Oriented Low-Power Test-Compression Architecture for Scan Designs

Massive test data volume and excessive test power consumption have become two strict challenges for very large scale integrated circuit testing. In BIST architecture, the unspecified bits are randomly filled by LFSR reseeding-based test compression scheme, which produces enormous switching activities during circuit testing, thereby causing high test power consumption for scan design. To solve the above thorny problem, LFSR reseeding-oriented low-power test-compression architecture is developed, and an optimized encoding algorithm is involved in conjunction with any LFSR-reseeding scheme to effectively reduce test storage and power consumption, it includes test cube-based block processing, dividing into hold partition sets and updating hold partition sets. The main contributions is to decrease logic transitions in scan chains and reduce specified bit in test cubes generated via LFSR reseeding. Experimental results demonstrate that the proposed scheme achieves a high test compression efficiency than the existing methods while significantly reduces test power consumption with acceptable area overhead for most Benchmark circuits.     

采用字典词条衍生模式的测试数据压缩

为了降低数字集成电路测试成本,压缩预先计算的测试集是一种有效的解决途径。该文根据索引位数远少于字典词条,以及测试数据中存在大量无关位,提出一种采用词条衍生和二级编码的字典压缩方案。该方案引入循环移位操作,确保无关位按序任意移动而不丢失,从而扩大词条衍生性能,减少非词条向量个数。另外,采用规则的两级编码可以减少码字数量和解压电路的复杂度。实验结果表明该文所提方案能够进一步提高测试数据压缩率,减少测试时间。     

基于51核的AES算法高速硬件设计与实现

为提高算法的效率,降低密钥运算的复杂度,提升密钥抵抗强力攻击和时间攻击能力,提出一种AES的算法方案。阐述了AES算法原理及片上系统执行AES的工作流程,基于8051软核AES算法IP原理、设计流程以及硬件模块的实现方案,并给出了效率分析及在硬件平台上的验证结果。仿真结果显示,用查表法实现AES,其IP核具有高效性,并可为密码SoC产品的开发体统算法引擎支持。相比较于以往的算法模型,该方案用少量面积换取速度,大幅提高了算法的效率,因此具备良好的应用价值。