Patent ID: 9160344
Filing Date: 2015-10-13
Classification: H03B,H03L

Abstract:
1. A method of starting up a crystal oscillator with a crystal and an oscillator circuit connected to a non-volatile memory, where a parameter which controls a drive level of the crystal is configured, the method comprising: setting the value of the parameter to a start-up value where the associated drive level is high enough to assure that the crystal oscillator begins to oscillate, modifying the value of the parameter such as to monotonically reduce the drive level of the crystal while monitoring the crystal oscillator, determining, in the course of monitoring the crystal oscillator, a breakdown value of the parameter where the crystal oscillator ceases to operate regularly, employing as a criterion of regular operation the condition that a cycle count of the crystal oscillator signal does not deviate from a cycle count of a reference signal by more than a predetermined amount, and selecting an operating value of the parameter such that the drive level associated with said operating value is above the drive level associated with the breakdown value by a safety margin.