Patent ID: 7120813
Filing Date: 2006-10-10
Classification: G06F

Abstract:
1. A method for generating a local clock signal responsive to receiving signals on a Universal Serial Bus (“USB”), the method comprising the steps of: a) generating a frequency-bearing local clock signal using a free running oscillator on an integrated circuitry chip of a device coupled to the USB, wherein the oscillator runs at a frequency that is substantially stable, but for an initial operation the oscillator has a period known with substantial inaccuracy; b) extracting a single ended bit-serial signal from received signals sent by a USB host or hub; c) asserting timing signals responsive to the single ended bit-serial signal; d) detecting bit patterns in the single ended bit-serial signal; e) measuring intervals between two bit patterns during which the timing signals are asserted; and f) adjusting the period P of the local clock signal responsive to one of the measured intervals.