Comparison between Quasi-Uniform Linear Cellular Automata and Linear Feedback Shift Registers as Test Pattern Generators for Built-in Self-Test Applications

Paulo Sérgio CardosoMarius StrumJosé Roberto de A. AmazonasWang Jiang Chau

Linear feedback shift registers (LFSRs) and cellular automata (CA) are well known structures that generate pseudo-random vector sequences. Quasi-Uniform Linear Cellular Automata (QULCA) were shown to be the simplest (most uniform) CAs capable of generating maximum length sequences [4]. In this paper we compare the performance between two types of QULCA, called QULCA90 and QULCA150, and two particular types of LFSRs, namely, QULFSRMIN and QULFSRMAX. They present respectively the minimum and maximum number of EXOR gates in their feedback path, while still generating maximum length sequences. These four types of structures present good characteristics when used as TPGs in a high level synthesis environment for Built-In Self-Testable (BIST) applications [2]. The comparison was based on the area overhead required to generate each structure and on the test length required to achieve a given Fault Coverage (FC). The well known ISCAS 85 benchmark circuits were used in our work. We show that in most cases the QULCA present superior performance than the better known LFSRs while not consuming much more area.

Caso o link acima esteja inválido, faça uma busca pelo texto completo na Web: Buscar na Web

Biblioteca Digital Brasileira de Computação - Contato:
     Mantida por: