Apple Inc.

Alexander Ukanwa

Charles Francis Dominguez

Michael Bekerman

Christopher D Finan

Kalpana Bansal

Remi Clavel

Jean-Didier Allegrucci

Jeffrey J Irwin

A method and apparatus for synchronizing a timebase is disclosed. A timebase management circuit includes limit circuitry, in a first clock domain, which generates, based on a global timebase, an initial timebase limit. The timebase management circuit includes, in a second clock domain, adjustment circuitry that generates an adjusted timebase limit based on the initial timebase limit. A storage circuit in the second clock domain stores a local timebase. Update circuitry, coupled to an output of the storage circuit, generates an updated local timebase using a clock signal in the second clock domain, wherein the updated local timebase is subject to the adjusted timebase limit.

Precise time management using local time base

An apparatus for time management of a peripheral device is disclosed. A peripheral interface circuit receives information from a host circuit over a peripheral bus, the host circuit maintaining a global timebase in accordance with a first clock signal within a first clock domain. The peripheral interface circuit maintains, based om a second clock signal within a second clock domain, a first local timebase correlated to the global timebase. A peripheral control circuit operates in a third clock domain and maintains a second local timebase based on the first. The peripheral interface circuit determines phase and frequency differences between the second and third clock signals in determining a correlation between the second and first local timebases. A peripheral logic circuit in the third clock domain performs, operations that utilize a timestamp from the second local timebase, which accounts for correlation with the first local timebase.

Precise time management for peripheral device using local time base

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Morgan Hill, CA, United States of America

Alexander Ukanwa