E-groups: a new technique for fast backward propagation in system-level test generation

This paper presents a new test pattern generation technique for complex systems. It focusses on test vector propagation through the individual blocks in the system. The technique is based on an easy identification of input-output pairs in each block. E (equality)-groups are formed for each block such that all the input vectors producing an identical output are grouped together. Such a grouping speeds up the task of backward propagation. In contrast to earlier methods, which considered the circuit structure for propagation, this method uses a functional approach and propagates the entire vector in one step. It is especially relevant to systems which consist of several blocks through which the test vector must be propagated. Results show that a significant reduction in the test generation time is possible.