Modeling timing correlation and the accurate timing verification of digital interface circuits

Recent research on timing verification of digital interface circuits has implicitly assumed that the delays of different signal transitions in the circuit are independent of one another. However timing diagrams in data sheets clearly specify correlation information. If timing correlation is ignored the results of verification can be overly pessimistic. In this paper we propose a probabilistic timed Petri net capable of representing timing correlation. For the subclass of periodic nets with AND and OR causality we develop a procedure that not only accurately checks if each one of the given timing constraints is satisfied but if the check fails also determines the probability that a particular timing constraint would be violated.