Patent US5355397A successfully refreshed from Google Patents.
US5355397A
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Clock start up stabilization for computer systems
Assignee: Silicon Graphics International Corp
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Filing: 1992-09-24
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Granted: 1994-10-11
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Expires: 2012-09-24
Abstract
Abstract Utilization circuits, such as logic chip circuits, are prevented from receiving the initial one or more pulses of a train of clock pulses produced after the master system clock is started, while the pulses of that train occurring thereafter are coupled to the utilization circuit. This prevents the skew usually present between the initial pulses of the train relative to the subsequent train pulses from adversely effecting operation of the utilization circuits. This clock swallowing preferably blocks a certain predetermined number of initial clock pulses from reaching the rest of the circuitry, although the system is adaptable to allow preselection of the number of such swallowed pulses.
Inventors
- 👤 David A. Hanson
- 👤 Edward C. Priest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:34
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/04; G06F1/10; H; H03; H03K; H03K5/00; H03K5/13
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
147 words
A method of preventing skew of at least an initial clock pulse of a train of clock pulses from a clock source from effecting functional operation of a utilization circuit, the method comprising the steps of: enabling the clock source to begin producing a train of clock pulses and a train of delayed clock pulses, blocking at least the first of the pulses of the train of clock pulses produced by the clock source from reaching the utilization circuit, blocking at least the first of the pulses of the train of delayed clock pulses produced by the clock source from reaching the utilization circuit. counting a predetermined number of clock pulses from the clock source, and responding to the occurrence of said predetermined number of clock pulses pursuant to said counting step for coupling said clock pulses and said delayed clock pulses to the utilization circuit thereafter.
Claim 2
Independent Claim
147 words
A method of preventing skew of at least an initial clock pulse of a train of clock pulses from a clock source from effecting functional operation of a utilization circuit, the method comprising the steps of: enabling the clock source to begin producing a train of clock pulses and a train of delayed clock pulses, blocking at least the first of the pulses of the train of clock pulses produced by the clock source from reaching the utilization circuit, blocking at least the first of the pulses of the train of delayed clock pulses produced by the clock source from reaching the utilization circuit. counting a predetermined number of clock pulses from the clock source, and responding to the occurrence of said predetermined number of clock pulses pursuant to said counting step for coupling said clock pulses and said delayed clock pulses to the utilization circuit thereafter.
Claim 3
Dependent Claim
153 words
Apparatus for preventing skew of at least an initial clock pulse of a train of clock pulses from a clock source from effecting functional operation of a utilization circuit comprising: means enabling said clock source to begin producing a train of clock pulses at a first terminal and a train of delayed clock pulses at a second terminal, counter memos coupled to said first terminal for receiving the pulses of said train of pulses for producing a first output signal in response to reception of a predetermined number of clock pulses from said clock source and a second output signal at a predetermined time subsequent to said first output signal, first means enabled by said counter means first output signal for coupling said first terminal clock pulses to the utilization circuit thereafter, and second means enabled by said second output signal for coupling said second terminal delayed clock pulses to the utilization circuit.
Claim 4
Dependent Claim
153 words
Apparatus for preventing skew of at least an initial clock pulse of a train of clock pulses from a clock source from effecting functional operation of a utilization circuit comprising: means enabling said clock source to begin producing a train of clock pulses at a first terminal and a train of delayed clock pulses at a second terminal, counter memos coupled to said first terminal for receiving the pulses of said train of pulses for producing a first output signal in response to reception of a predetermined number of clock pulses from said clock source and a second output signal at a predetermined time subsequent to said first output signal, first means enabled by said counter means first output signal for coupling said first terminal clock pulses to the utilization circuit thereafter, and second means enabled by said second output signal for coupling said second terminal delayed clock pulses to the utilization circuit.
Claim 5
Dependent Claim
20 words
Apparatus in accordance with claim 2 wherein said counter means includes a plurality of stages the counting sequential clock pulses.
Claim 6
Dependent Claim
30 words
Apparatus in accordance with claim 3 wherein said counter means includes means for selecting the output of one of said plurality of stages for enabling said utilization circuit coupling means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-10 | 1998-04-11 | 1998-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-10 | 2002-04-11 | 2002-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-10 | 2006-04-11 | 2006-10-11 | $7700.00 | Window Closed / Lapsed |