This paper presents the ITC'02 SOC Test Benchmarks. The purpose of this new benchmark set is to stimulate research into new methods and tools for modular testing of SOCs and to enable the objective comparison of such methods and tools with respect to effectiveness and efficiency. The paper defines the benchmark format and naming scheme, and presents the benchmark SOCs. In addition, it provides an overview of the research problems that can be addressed and evaluated by means of this benchmark set. These research problems include the design of optimized test access infrastructures and test schedules.

INTRODUCTION Embedded cores are now increasingly being used in large system-on-a-chip (SOC) designs [Zorian et al. 1998]. These complex, predesigned functional blocks facilitate design reuse, allow greater on-chip functionality, and lead to shorter product development cycles. However, the manufacturing test and debug of such SOC designs remains a major challenge. Since embedded cores are not directly accessible via chip inputs and outputs, special access mechanisms are required to test them at the system level. The development of efficient test access architectures is therefore of considerable interest to the SOC design and test community. This research was supported in part by the National Science Foundation under grant CCR-9875324. An abridged version of this paper appeared in Proceedings of the IEEE VLSI Test Symposium, Montreal, Canada, May 2000, pp. 127-134. Author's address: Department of Electrical and Computer Engineering, Duke University, 130 H

Test data volume and power consumption for scan vectors are two major problems in system-on-a-chip testing. Since static compaction of scan vectors invariably leads to higher power for scan testing, the conflicting goals of low-power scan testing and reduced test data volume appear to be irreconcilable. We tackle this problem by using test data compression to reduce both test data volume and scan power. In particular, we show that Golomb coding of precomputed test sets leads to significant savings in peak and average power, without requiring either a slower scan clock or blocking logic in the scan cells. We also improve upon prior work on Golomb coding by showing that a separate cyclical scan register is not necessary for pattern decompression. Experimental results for the larger ISCAS 89 benchmarks show that reduced test data volume and low power scan testing can indeed be achieved in all cases.

We present a test resource partitioning (TRP) technique that simultaneously reduces test data volume, test application time, and scan power. The proposed approach is based on the use of alternating run-length codes for test data compression. We present a formal analysis of the amount of data compression obtained using alternating run-length codes. We show that a careful mapping of the don't-cares in precomputed test sets to 1's and 0's leads to significant savings in peak and average power, without requiring either a slower scan clock or blocking logic in the scan cells. We present a rigorous analysis to show that the proposed TRP technique reduces testing time compared to a conventional scan-based scheme. We also improve upon prior work on run-length coding by showing that test sets that minimize switching activity during scan shifting can be more efficiently compressed using alternating run-length codes. Experimental results for the larger ISCAS89 benchmarks and an IBM production circuit show that reduced test data volume, test application time, and low power-scan testing can indeed be achieved in all cases.

Abstract—A test solution for a complex system requires the design of a test access mechanism (TAM), which is used for the test data transportation, and a test schedule of the test data transportation on the designed TAM. An extensive TAM will lead to lower test-application time at the expense of higher routing costs, compared to a simple TAM with low routing cost but long testing time. It is also possible to reduce the testing time of a testable unit by loading the test vectors in parallel, thus increasing the parallelization of a test. However, such a test-time reduction often leads to higher power consumption, which must be kept under control since exceeding the power budget could damage the system under test. Furthermore, the execution of a test requires resources and concurrent execution of tests may not be possible due to resource or other conflicts. In this paper, we propose an integrated technique for test scheduling, test parallelization, and TAM design, where the test application time and the TAM routing are minimized, while considering test conflicts and power constraints. The main features of our technique are the efficiency in terms of computation time and the flexibility to model the system’s test behavior, as well as the support for the testing of interconnections, unwrapped cores and user-defined logic. We have implemented our approach and made several experiments on benchmarks as well as industrial designs in order to demonstrate that our approach produces high-quality solution at low computational cost. Index Terms—Scan-chain partitioning, system-on-chip (SOC) testing, test access mechanism design, test data transportation, test scheduling, test solutions. I.

This paper describes an integrated framework for plug-and-play SOC test automation. This framework is based on a new approach for wrapper/TAM co-optimization based on rectangle packing. We first tailor TAM widths to each core's test data needs. We then use rectangle packing to develop an integrated scheduling algorithm that incorporates precedence and power constraints in the test schedule, while allowing the SOC integrator to designate a group of tests as preemptable. Finally, we study the relationship between TAM width and tester data volume to identify an effective TAM width for the SOC. We present experimental results for non-preemptive, preemptive, and power-constrained test scheduling, as well as for effective TAM width identification for an academic benchmark SOC and three industrial SOCs.

Abstract 1 This paper presents a solution to the test time minimization problem for core-based systems that contain sequential cores with STUMPS architecture. We assume a hybrid BIST approach, where a test set is assembled, for each core, from pseudorandom test patterns that are generated online, and deterministic test patterns that are generated offline and stored in the system. We propose a methodology to find the optimal combination of pseudorandom and deterministic test sets of the whole system, consisting of multiple cores, under given memory constraints, so that the total test time is minimized. Our approach employs a fast estimation methodology in order to avoid exhaustive search and to speed-up the calculation process. Experimental results have shown the efficiency of the algorithm to find near optimal solutions. 1.

Test scheduling is an important problem in system-on-a-chip (SOC) test automation. Efficient test schedules minimize the overall system test application time, avoid test resource conflicts, and limit power dissipation during test mode. In this paper, we present an integrated approach to several test scheduling problems. We first present a method to determine optimal schedules for reasonably sized SOCs with precedence relationships, i.e., schedules that preserve desirable orderings among tests. We also present an efficient heuristic algorithm to schedule tests for large SOCs with precedence constraints in polynomial time. We describe a novel algorithm that uses preemption of tests to obtain efficient schedules for SOCs. Experimental results for an academic SOC and an industrial SOC show that efficient test schedules can be obtained in reasonable CPU time.

Test scheduling is a major problem in system-on-a-chip (SOC) test automation. We present an integrated framework that addresses several important test scheduling problems. We first present efficient techniques to determine optimal SOC test schedules with precedence constraints, i.e., schedules that preserve desirable orderings among tests. We then present a new algorithm that uses preemption to obtain optimal test schedules in polynomial time. Finally, we present a new method for determining optimal power-constrained schedules. Experimental results for a representative SOC show that test schedules can be obtained in reasonable CPU time for all cases. 1 Introduction Pre-designed and pre-verified intellectual property (IP) cores are being increasingly used in complex system-ona -chip (SOC) designs. IP cores lead to short design cycle times since a plug-and-play approach can be used to build an entire system consisting of processors, memories, and peripherals. However, testing these sys...

Abstract 1 We propose an integrated technique for extensive optimization of the final test solution for System-on-Chip using Simulated Annealing. The produced results from the technique are a minimized test schedule fulfilling test conflicts under test power constraints and an optimized design of the test access mechanism. We have implemented the proposed algorithm and performed experiments with several benchmarks and industrial designs to show the usefulness and efficiency of our technique. 1