Digital Logic Testing and Simulation, 2nd Edition

CHAPTER 7

Developing a Test Strategy

7.1 INTRODUCTION

The first five chapters provided a survey of algorithms for logic simulation, fault simulation, and automatic test pattern generation. That was followed by a brief survey of tester architectures and strategies to maximize tester effectiveness while minimizing overall test cost. We now turn our attention to methods for combining the various algorithms and testers in ways that make it possible to achieve quality levels consistent with product requirements and design methodologies.

It has been recognized for some time now that true automatic test pattern generation is a long way from realization, meaning that software capable of automatically generating high-quality tests for most general sequential logic circuits does not currently exist, nor is it likely to exist in the forseeable future. Hence, it is necessary to incorporate testability structures in digital designs to make them testable.

We begin this chapter with a look at the design and test environment. That will provide a framework for discussion of the various topics related to test and will help us to see how the individual pieces fit together. Most importantly, by starting with a comprehensive overview of the total design and test process, we can identify opportunities to port test stimuli created during design verification into the manufacturing test development process. ...