An RC oscillator generates a periodic trigger signal, and a clock generator generates clock edges in response. A stuck-at-fault detection circuit detects a stuck-at-logic state of the periodic trigger signal and causes the RC oscillator to reset and causes a change in logic state of the periodic trigger signal. The RC oscillator includes first and second comparison circuits, a logic circuit receiving output from the first and second comparison circuits and generating the periodic trigger signal, and a clock generation circuit generating a clock signal therefrom. The stuck-at-fault detection circuit includes a capacitive node, charge circuitry charging the capacitive node based upon the periodic trigger signal, discharge circuitry discharging the capacitive node based upon the periodic trigger signal, and triggering circuitry asserting a reset signal to cause the RC oscillator to reset when the charge on the capacitive node indicates a stuck-at-logic state of the periodic trigger signal.