A check engine includes comparators, where each comparator has flash cells. Each comparator is configured to store at least one reference bit included in a set of reference bits defining a first pattern. Each comparator also includes an input for presenting at least one target bit included in a set of target bits defining a second pattern. Each comparator is configured to produce an output representing a level of matching between the at least one target bit and the at least one reference bit. The check engine is configured such that the outputs of the comparators are combined to produce a combined output that is compared to a reference signal to determine whether there is a match between the first pattern and the second pattern.