Abstract: An apparatus and method for determining a linear position from a linear variable differential transformer (LVDT) including a primary coil driven by an excitation signal, and two secondary coils coupled to two correlated signals. The method includes converting the correlated signals to a digital estimate, for each of the correlated signals, and evaluating an amplitude of the correlated signals to determine the linear position. The process of converting the correlated signals comprises comparing the correlated signal to an analog feedback signal to generate a comparison result and incrementally adjusting the digital estimate in response to sampling the comparison result at an estimation frequency.

Abstract: A watchdog timer circuit includes a cyclic counter having an overflow signal that functions as a reset pulse to a microprocessor. The timer circuit includes a feature for selectively supplanting the overflow signal to enable in situ programming of the microprocessor.