On controllability estimation to aid in partitioning logic circuits

The authors present a computer-aided test tool, PACE (Partitioning Aid and Controllability Estimator), which provides controllability estimation and interfaces with a partitioning-for-testability tool. When interfaced with a partitioning tool, PACE can be used for verifying the optimum number of partitions. It utilizes controllability estimation to help designers early in the design cycle. In PACE, two transfer factors, the zero-controllability transfer factor and one-controllability transfer factor, are defined for each primitive device. The zero-controllability index, one-controllability index and average-controllability index are three indices which are calculated across a primitive device for each line of a circuit. In addition, there is an overall-controllability index for the whole circuit. PACE can be used for both combinational and sequential circuits