Design for testing

About: Design for testing is a research topic. Over the lifetime, 3946 publications have been published within this topic receiving 63049 citations. The topic is also known as: Design for Testability, DFT.

Non-scan design for testability for synchronous sequential circuits based on conflict analysis

Abstract: A non-scan design for testability method is presented for synchronous sequential circuits. A testability measure called conflict based on conflict analysis in the process of synchronous sequential circuit test generation is introduced. Reconvergent fanouts with nonuniform inversion parity are still the main cause of redundancy and backtracking in the process of sequential circuit test generation. A new concept called sequential depth for testability is introduced to calculate the conflict-analysis-based testability measure. Potential conflicts between fault effect activation and fault effect propagation are also checked because they are closely related. The testability measure implies the number of potential conflicts to occur or the number of clock cycles required to detect a fault. The non-scan design for testability method based on the conflict measure can reduce many potential backtracks, make many hard-to-detect faults easy-to-detect and many redundant faults testable, therefore, can enhance fault coverage of the circuit greatly. It is believed that non-scan design for testability using the conflict measure can improve the actual testability of a circuit. Extensive experimental results are presented to demonstrate the effectiveness of the method.

Experiences gained using the Navy's IDSS weapon system testability analyzer

Abstract: The weapon system testability analyzer (WSTA), which has the ability to measure the testability of a design by modeling the actual process used during online, real-time fault diagnosis, is described. The results of experiences gained applying the ESTA to various levels of analysis are presented, including: built-in test (BIT) assessment at the organizational level; verification of complete testability from system, subsystem, and weapon replacable assembly (or line-replaceable unit) levels; and, through card-level testability, detection and isolation accurately and efficiently at the piece-part level. The ease of modeling, the reports generated and their usefulness to the testability process, and the unique features associated with the use of the tool are discussed. >

From Design Validation to Hardware Testing: A Unified Approach

Abstract: In this paper we propose a new approach that addresses both the problems of design validation and hardware testing since the early stages of the design flow. The approach consists in adapting the mutation testing, a software method, to circuits described in VHDL. At the functional level, the approach behaves as a design validation method and at the hardware level as a classical ATPG. Standard software test metrics are used for assessing the quality of the design validation process, and the hardware fault coverage for assessing the test quality at the hardware level. An enhancement process that allows design validation to be efficiently reused for hardware testing is detailed. The approach is shown to be efficient upon a set of representative circuits.

Scan attack in presence of mode-reset countermeasure

Abstract: Design for testability (DFT) is the most common testing technique used in the modern VLSI industries. However, when this technique is incorporated in a cryptographic circuit, it may open a back door to an attacker. The attacker can get access to the internal scan chains by switching the device from the normal mode to the test mode and then observe the chip content. The scan cells which were originally used to enhance the testability, can thus be misused to access the intermediate results of the cryptographic algorithm running inside the chip. One countermeasure against such attacks is to reset the device whenever there is a switch from the normal mode to the test mode. In this work we are going to analyse this countermeasure and show that it is not completely secure against scan attack. We show that an attack is possible using only the test mode which will bypass the countermeasure.