AN2678极其精确的计时，超过温度自适应校正

AN2678极其精确的计时，超过温度自适应校正

AN2678
Application note
Extremely accurate timekeeping over
temperature using adaptive calibration

Introduction
Typical real-time clocks use common 32,768 Hz watch crystals. These are readily available
and relatively inexpensive, but they suffer a loss of accuracy when operated over wide
temperature ranges. However, the ultra-low power characteristics of 32 KHz oscillators
make them ideal, and necessary, for battery backed applications.
Conversely, the higher speed, AT-cut crystals used with microp