Low Power Automatic Calibration Method for High Frequency Oscillators

摘要

A clock calibrator for use in an electronic system comprising an integrated circuit such as a microcontroller. The clock calibrator embodies a frequency adjustment facility adapted dynamically to adjust the frequency of one or more high-frequency clock generators as a function of a lower-frequency reference clock.

主权项

1. A clock calibration method comprising the steps of:
[1] in response to a first control signal:
[1.1] in response to a second control signal, selectively enabling a reference clock oscillator to develop reference clock pulses at a selected reference frequency; and[1.2] in response to a third control signal, selectively enabling a measured clock oscillator to develop measured clock pulses at a frequency determined as a function of an adjustment value; [2] in response to a first one of the reference clock pulses, initiating counting of the measured clock pulses; [3] in response to a second reference clock pulse, terminating counting of the measured clock pulses; and [4] adjusting the adjustment value as a function of a difference between the count of the measured clock pulses and a selected target value.