A memory system circuit and method therefor are disclosed. The circuit is adapted to detect a transition in a data timing signal from an indeterminate logic level to a selected one of a high logic level and a low logic level. The circuit includes a comparator having a first input, a second input and an output. The first and second inputs receive the data timing signal and a reference voltage respectively. The output changes logic levels in response to a change in polarity of a voltage difference between the voltage of the timing signal and the reference voltage. The reference voltage is sufficiently closer to the selected one of the logic levels as compared to the other of the logic levels so as to at least substantially prevent potential false positive detections.