Can Crystal Oscillators Keep Time Without Power?

Abstract

Accurate timekeeping is a critical challenge for many intermittently-powered computing devices. Current approaches to keeping time across power failures provide either limited resolution or require additional hardware. We would like to introduce one more. Many devices already use a crystal oscillator for accurate timing when powered. In this poster, we explore whether we can use the off-the-shelf oscillators we're already using to keep time even when we don't have power. We present early-stage experimental results, using the oscillator's stabilization time to approximate power outage times. We will also discuss the strengths, weaknesses, likely applications, and future directions of this work.