On-chip constrained random stimuli generation for post-silicon validation using compact masks

During post-silicon validation a large number of constrained random stimuli are applied to expose the subtle design errors that have escaped to the silicon prototypes. In this paper we present a new method to design constrained random stimuli generators, which are programmable and can be placed on-chip to generate extensive random, yet functionally-compliant, sequences for real-time/in-system validation. The basic idea is to translate the constraints for constrained-random variables into binary cubes, whose specified values are used as masks to correct random sequences. To reduce the volume of data needed to be placed on-chip, the cubes are efficiently encoded and expanded in real-time. Experimental results confirm the effectiveness of this new method when compared against the prior work on the topic.