automatic power saving for decreasing power demand during a power interruption while maintaining the appearance of full operation of a signal processor including predefined power consuming circuits , a communications interface , and a state machine includes sensing when a power supply interruption has occurred , providing a clock signal , halting the clock signal to the predefined power consuming circuits during a power interruption ; and continuing to provide a clock signal to a communications interface regardless of a sensed interruption for maintaining the appearance of normal operations during the sensed interruption .