A circuit comprises a position sensing circuit to sense first and second position states of a rotating object, a first counter storing a first counter value, and a second counter storing a second counter value. The first counter value is incremented when the position states are the same, the second counter value is incremented when the position states indicate that the rotating object has rotated in a direction, and a fault is indicated when either counter value is equal to or greater than their respective limits. A method comprises sensing two position states of a rotating object, incrementing a first counter value when the position states are the same, incrementing a second counter value when the rotating object is determined, using the position states, to have rotated in a direction, and indicating a fault when either counter value is equal to or greater than their respective limits.