1. Introduction

Abstract

Nowadays a great part of computing components is found in embedded systems for control and signal processing applications. The trend of embedded computer designs is moving towards single-chip solutions. So called systems-on-chip (SOCs) include various reusable functional blocks such as microprocessors, DSPs, accelerators, memories, and interfaces (embedded cores). The complexity of such systems causes a lot of new problems for developers and users. During the last 15 years, CMOS scaling offered new opportunities to system architects because of increasing frequency, transistor density and die size. On the other hand, the work of test engineers has become more complicated.

The integration of various cores on one chip hinders test by traditional methods because of inadequate accessibility to partial components. The probability of design and manufacturing defects not detected during IC production test grows with higher complexity. Additional influences and aging effects may cause system failure. Devices become more susceptible to transient faults due to increasing clock frequency and lower voltage swings between logic levels.