An apparatus for use in obtaining a value from a device includes a first comparator to receive a reference high signal and a device signal, where the first comparator provides a first output signal to indicate whether the device signal is above or below the reference high signal, and a second comparator to receive a reference low signal and the device signal, where the second comparator provides a second output signal to indicate whether the device signal is above or below the reference low signal. Also included in the apparatus is circuitry (i) to adjust at least one of the reference high signal and the reference low signal based on the first output signal and the second output signal, and (ii) to output the value if a difference between the reference high signal and the reference low signal meets a predetermined criterion, the value being based on the difference.