Providing fault-tolerant spread spectrum clock signals in a system
AssigneeHewlett-Packard Development Company, L.P.
InventorsRangaswamy Arumugham, Stuart Haden, Mark A. Shaw
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Abstract
To provide fault-tolerant, spread spectrum clock signals, a plurality of processing modules having respective spread spectrum control circuits are provided. Clock signals of redundant clock sources are provided to the plurality of processing modules. Failover control logic selects a corresponding one of the clock signals from the redundant clock sources for use in each of the processing modules. Frequency spreading is applied to the corresponding selected clock signal in each of at least some of the plurality of processing module.
Claims15
A system in which is provided fault-tolerant, spread spectrum clock signals, comprising:
- a plurality of processing modules provided in one or more enclosures, wherein the processing modules include corresponding clock spread spectrum control circuits;
- and
- a plurality of redundant clock sources providing respective clock signals to the plurality of processing modules,
- wherein each of the clock spread spectrum circuits is configured to apply frequency spreading to a corresponding selected one of the clock signals, and
- wherein each of the processing modules includes a failover control logic to monitor clock signals from the redundant clock sources to perform clock signal failover, and
- wherein at least a particular one of the spread spectrum circuits is to receive one of the clock signals and to produce at least a first clock output, wherein frequency spreading is disabled for the first clock output.
A method of providing fault-tolerant, spread spectrum clock signals, comprising:
- providing a plurality of processing modules having respective spread spectrum control circuits;
- providing clock signals of redundant clock sources to the plurality of processing modules;
- selecting, by failover control logic, a corresponding one of the clock signals from the redundant clock sources for use in each of the processing modules;
- applying frequency spreading to the corresponding selected clock signal in each of at least some of the plurality of processing module;
- and
- producing a first clock output when at least a particular one of the spread spectrum circuits receives one of the clock signals, wherein frequency spreading is disabled for the first clock output.
A first processing module for use in a system having multiple processing modules, comprising:
- a clock failover logic to receive clock signals from plural clock sources and to select one of the plural clock signals for use in the processing module;
- a spread spectrum control circuit to
- receive the selected clock signal and to apply frequency spreading to the selected clock signal, wherein the spread spectrum control circuit is independently controllable from at least another spread spectrum control circuit provided in another one of the multiple processing modules;
- and
- receive one of the clock signals and produce at least a first clock output, wherein frequency spreading is disabled for the first clock output.
Dependencies are inferred from the claim text.