Test Cost Reduction for SoC Using a Combined Approach to Test Data Compression and Test Scheduling

As test data continues to grow quickly, test cost also increases. For the sake of decreasing the test cost, this article presents a new data dependency compression scheme for large circuit which is based on multiple scan chains. We propose new compression architecture with fixed length for running tests. In results, when the complexity of a VLSI circuit is growing, the number of input pins for testing is very low. Since test data in power aware is not changed frequently, we use a selector to filter the unnecessary status and buffers to hold the back data. We also propose a new algorithm to assign multiple scan chains and an improved linear dependency compute method to find the hidden dependency between scan chains. Experimental results show that the proposed method can reduce both test data volume and shift-in power.

Scan architectures, though widely used in modern designs for testing purpose, are expensive in test data volume and power consumption. To solve these problems, we propose in this paper to modify an existing test data compression technique (Wang Z, Chakrabarty K in Test data compression for IP embedded cores using selective encoding of scan slices. IEEE International Test Conference, paper 24.3, 2005) so that it can simultaneously address test data volume and power consumption reduction for scan testing of embedded Intellectual Property (IP) cores. Compared to the initial solution that fill don't-care bits with the aim of reducing only test data volume, here the assignment is performed to minimize also the power consumption. The proposed power-aware test data compression technique is applied to the ISCAS'89 and ITC'99 benchmark circuits and on a number of industrial circuits. Results show that up to 14× reduction in test data volume and 98% test power reduction can be obtained simultaneously.

In this paper, we propose a new test data compression method for reducing test data volume and test application time. The proposed method consists of two steps: scan chain compaction and dictionary-based compression scheme. The scan chain compaction provides a minimum scan chain depth by using compaction of the compatible scan cells in the scan chain. The compacted scan chain is partitioned to the multiple internal scan chains for using the fixed-length index dictionary-based compression scheme that provides the high compression ratio and the fast testing time. The proposed compression method delivers compressed patterns from the ATE to the chip and drives a large number of multiple internal scan chains using only a single ATE input and output. Experimental results for the ISCAS-89 test benches show that the test data volume and testing time for the proposed method are less than previous compression schemes.

With the increasing complexity and chip scale of SoC, the test problem is becoming more difficult and important. Adding DFT (design for testability) in SoC design period has become the main method for solving the test problem. Based on analyzing some common DFT structures such as Fscan-Bscan, Fscan-Tbus, and the standard for embedded core test (SECT) IEEE P1500, a system-level mixed DFT-TAM (test access mechanism) structure has been presented in this paper. In this structure, different DFT methods are applied in different characteristic IP (intellectual property) cores to pursue the reasonable testing cost, then, a more flexible TAM is built in the system level for achieving every IP core test and testing the connection faults between two IP cores. By some experiments with the programmable video add data (VAD) SoC introduced in this paper, the higher fault coverage and lower test cost could be gotten

This paper proposes an improved procedure to watermark soft Intellectual Property (IP) Cores at the Register Transfer Level (RTL) using Genetic Algorithms (GA). In order to merge the watermark signature and the IP Core's behavioral description, both are translated into Finite State Machines (FSM). The resulting FSM contains the watermarked IP Core maintaining its original functionality without disruption. However, a set of hanging states (a group of states not deeply embedded) has been observed and if any of these is deleted, the watermark could be removed and possibly the original IP Core functionality would not be disrupted, allowing for copyright infringements. Thus, a reduction procedure is applied to the watermarked design to reduce the number of hanging states, which to the best of the authors' knowledge has not been developed. Both FSM merging and reduction are NP-Complete problems. In this study, an improved objective function is proposed to accurately model the FSM reduction problem while applying GAs as optimization techniques at both stages. Empirical results show a significant improvement in terms of the number of final hanging states and watermark embedding strength as regards previous reported approaches.

Today’s scenario of semiconductor technology is a tremendous innovation; it includes a large number of intellectual property (IP) cores, interconnects, or buses in system on chip (SOC) design and based upon the necessity its complexity keeps on increasing. Hence, for the communication between these IP cores, a standard protocol is developed. The necessity of IP reuse, abridging the design time and the complexity makes large-scale SOC more challenging in order to endorse IP core reusability for SOC designs. An efficient non-proprietary protocol for communication between IP cores is open core protocol (OCP). OCP comes under socket-based interface and openly licensed core concentric protocol. This paper addresses on the verification of implemented design of OCP. The proposed paper is to verify the implemented design by using System Verilog and Universal Verification Methodology (UVM) in SimVision tool.

This paper introduces a multi-channels data synchronous acquisition and processing IP (intellectual property) core for digital protective relay. It integrates data acquisition and processing in one FPGA, resolving problem of asynchrony between data acquisition and data processing as well as setting of the number of sampling channels and sampling points per period. In contrast to the traditional acquisition system, it has characteristic of high speed, flexibility and low cost. This IP core was verified in FPGA (field programmable gate array) based hardware platform. The result of experiment indicates that this IP core is correct and can be used into SOC (system on chip) application as a single module.

Modern Systems-on-a-Chip (SoC) are constructed by composition of IP (Intellectual Property) Cores with the communication between these IP Cores being governed by well described interaction protocols. However, there is a disconnect between the machine readable specification of these protocols and the verification of their implementation in known hardware description languages. Although tools can be written to address such a separation of concerns, such tooling is often hand written and used to check hardware designs a posteriori. We have developed a dependent type-system and proof-of-concept modelling language to reason about the physical structure of hardware interfaces respective to user provided descriptions. Our type-system provides correct-by-construction guarantees that the interfaces on an IP Core will be well-typed if they adhere to a specified standard.

A test pattern compression scheme for test data volume and application time reduction is proposed. While compression reduces test data volume, the increased number of internal scan chains due to an on-chip, fixed-rate decompressor reduces test application time proportionately. Through on-chip decompression, both the number of virtual scan chains visible to the ATE and the functionality of the ATE are retained intact. Complete fault coverage is guaranteed by constructing the decompression hardware deterministically through analysis of the test pattern set.

This paper proposes a novel boundary scan test scheme for intellectual property (IP) core identification via watermarking. The core concept is embedding a watermark identification circuit (WIC) and a test circuit into the IP core at the behavior design level. The procedure depends on current IP-based design flow. This scheme can detect the identification of the IP provider without the need to examine the microphotograph after the chip has been manufactured and packaged. This scheme can successfully survive synthesis, placement, and routing and identify the IP core at various design levels. Experimental results have demonstrated that the proposed approach has the potential to solve the IP identification problem.

Broadcast-based test compression techniques can reduce both test data and test time. However, the success of such methods heavily depends on the percentage of test patterns that can be broadcasted. In this paper, we first conduct a quantitative analysis that shows the simple broadcast architecture that cannot achieve good test time/data compression even under a test set with very high level of don't care bits. A multi-mode-segmented scan test architecture (MSSA) is then presented to solve the problem of low broadcast rate. Three operation modes are supported in this architecture: broadcast, multicast and serial. As a result, improved test data compression is achievable with limited hardware overhead, as serial-mode operations are largely eliminated. An algorithm for the two-way partitions of the scan segments is proposed to construct multicast mode configurations. Finally, we present a layout-aware scan chain ordering method to further improve test compression. The problem of ordering scan cells in multiple scan chains is mapped to a constrained standard cell placement problem in physical synthesis, and the simulated annealing method is used to solve the problem. The routing length of the scan chains are also taken into account in the ordering process.

With the development of research on IEEE Std1500, IP (Intellectual Property) cores compatible with IEEE Std1500 are more and more. IEEE Std1500 provides wrapper architecture and TAM (Test Access Mechanism) for DFT (Design for Testability) of IP cores. So, the design of TAM becomes an important part of DFT for IP cores. Familiar TAM is introduced first, and then according to the characters of wrapper architecture, a TAM design based on bus is put forward. At last, TAM controller design for configurations of TAM is provided.

Design for Testability (DFT) based on scan and ATPG has been adopted as a reliable and broadly acceptable methodology that provides very high test coverage, but for large circuits, the growing test data volume causes a significant increase in test cost because of much longer test time and elevated tester memory requirements. Test compression or scan compression provides great reduction in test data volume and test time required by adding on-chip decompressor and compactor. In this paper comparative analysis are made for Broadcast, XOR decompressor along with XOR, MISR and Hybrid compactors with respect to test coverage, test cycles required and test data volume by considering Flash Interface as CUT. From the experiments, it is observed that XOR decompressor with MISR compactor architecture provides 17.31% to 49.76% reduction in test data volume compared to other architectures, with 99.76% of fault coverage, 16694 test cycles and 2104µm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of area overhead.

In the modern electronic era, the increased usability and acceptability of reusable intellectual property (IP) cores induce the necessity to secure them from various hardware security threats and attacks. This chapter presents a taxonomy of hardware security methodologies for IP cores and a detailed design flow of hardware integrated circuits (ICs) along with vulnerability points where potential attacks/threats are possible. Trustworthy and untrustworthy regimes in the design flow have also been highlighted in the discussion. Further, a discussion of detective and preventive control-based hardware security approaches used for hardware IP cores have also been presented, including an analysis of prominent structural obfuscation, logic locking (logic encryption), and IP core protection (IPP) techniques. Each approach has been lucidly explained in terms of its threat model, algorithm, and security analysis. Finally, a security comparison of hardware IP obfuscation approaches in terms of strength of obfuscation security metric as well as security comparison of IPP approaches in terms of probability of coincidence security metric have also been introduced.

The modus operandi of the upfront intellectual property (IP) licensing model is impractical for the developers of small to medium volume of field-programmable gate array (FPGA)-based applications. The FPGA IP market is in dire need for a more competitive and secure IP licensing scheme to flourish. In this paper, a pragmatic security protocol that could support the licensing of IP cores on a per-device basis without the need for a contractual agreement of an external trusted third party, large bandwidth, and complicated flow of communications is proposed. Besides assuring that the incentives of all stakeholders involved in the FPGA IP core trading are not scarified if not enhanced, the proposed protocol guarantees total secrecy and integrity of licensed IP cores based on available primitives of contemporary SRAM-based FPGA devices. It also prohibits the implementation of protected IP cores on unscreened excess devices and counterfeit chips sold in the gray market. The adoption of IP fingerprinting further deters the IP licensees from abusing the IP cores. Using the self-reconfiguration feature of FPGAs today, the resources consumed by the control module used for the implementation of protected IP cores on the authorized device are temporary and marginal.