Erwin Trischler

SOCRATES: a highly efficient automatic test pattern generation system

An automatic test pattern generation system, SOCRATES, is presented. SOCRATES includes several novel concepts and techniques that significantly improve and accelerate the automatic test pattern generation process for combinational and scan-based circuits. Based on the FAN algorithm, improved implication, sensitization, and multiple backtrace procedures are described. The application of these techniques leads to a considerable reduction of the number of backtrackings and an earlier recognition of conflicts and redundancies. Several experiments using a set of combinational benchmark circuits demonstrate the efficiency of SOCRATES and its cost-effectiveness, even in a workstation environment. >

A hierarchical test pattern generation system based on high-level primitives

The authors present an extension of the automatic test pattern generation system SOCRATES to a hierarchical test pattern generation system for combinational and scan-based circuits. The proposed system is based on predefined high-level primitives, e.g., multiplexers and adders. The exploitation of high-level primitives leads to significant improvements in implication, unique sensitization, and multiple backtrace, all of which play a key role in the efficiency of any automatic test pattern generation (ATG) system. In order to perform deterministic ATG and fault simulation for internal faults of high-level primitives, the high-level primitives are dynamically expanded to their gate-level realization. A number of experimental results, achieved on circuits with several tens of thousands of primitives, demonstrate the efficiency of the proposed approach in terms of CPU time, fault coverage, and memory requirements. >

Sensitivity analysis in economics based test strategy planning

This article will present methods to analyze the sensitivity of test costs to the inaccuracy of the individual costing parameters. The results show that a few parameters—e.g., the gate count—need very detailed estimates, whereas the accuracy of many other parameters is insignificant in 99% of all cases. The techniques presented allow an in-depth evaluation of what is perceived as the main drawback in the use of economic modeling methods, namely, the element of risk associated with inaccuracies in the input data.

Efficient sensitization of multi-bit-paths for testing embedded modules in synchronous sequential circuits

This article presents SPLASH, an algorithm that can sensitize several independent bitpaths simultaneously. SPLASH includes several new concepts and techniques aiming at a significant improvement and acceleration of the path sensitization for testing embedded modules in combinational and synchronous sequential circuits. The transparent paths are used to apply module test patterns through circuit inputs and observe the responses at circuit outputs. It consequently automates an important task of modular test generation, supplying a test pattern assembly program with a specification how to transform module test patterns into circuit level pattern.A number of experiments using combinational and sequential benchmark circuits as well as industrial designs demonstrate the efficiency of the approach.