1. An apparatus, comprising: a plurality of storage elements individually addressable by way of respective row address lines and column address lines; a ring oscillator configured to be selectively coupled to the storage elements by way of the row address lines and the column address lines so as to establish a feedback pathway, the ring oscillator characterized by an oscillation period correspondent to a data value stored within one of the storage elements coupled to the ring oscillator; and control circuitry configured to provide a digital signal in accordance with the oscillation period, and in accordance with a previously determined reference value for the plurality of storage elements.