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US5701441A Expired / Lapsed US ⏱️ 0.0 years remaining

Computer-implemented method of optimizing a design in a time multiplexed programmable logic device

Assignee: Xilinx Inc
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Filing: 1995-08-18
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Granted: 1997-12-23
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Expires: 2015-08-18
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Abstract

Abstract A computer-implemented method of optimizing a time multiplexed programmable logic device includes identifying a micro cycle, identifying all look-up tables (LUTs) from a list of LUTs of the PLD that may be scheduled in the micro cycle, ordering the LUTs in priority order, selecting the M LUTs with the highest priority (wherein M is the number of real LUTs in the PLD), labeling the M LUTs with the current micro cycle number, removing the M LUTs from the list, identifying the next micro cycle, and if labelled LUTs exist, then repeating all steps, otherwise exiting the computer-implemented method. The step of ordering alternatively includes identifying the LUTs with the earliest latest-possible schedule, identifying the LUTs having input nets in which all LUTs are already scheduled, identifying the LUTs that include a pin on a net that has had at least one of its destination instances scheduled, identifying the LUTs that will complete a net that may be introduced in the micro cycle by the addition of a LUT earlier in a list of the LUTs, or identifying the LUTs that include a pin on a net that may be introduced in the micro cycle by the addition of a LUT earlier in a list of the LUTs. In another embodiment, the method includes the first three steps, then further includes determining whether the number of selected LUTs is equal to M, wherein M is the number of real LUTs in the programmable logic device. The steps of labeling and removing are repeated until the number of selected LUTs is equal to M. Then, the M LUTs with the current micro cycle number are labelled and removed from the list. The next micro cycle is then identified. If labelled LUTs exist, then all steps are repeated.

Inventors

  • 👤 Stephen M. Trimberger

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 16:33
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/34

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 110 words
A computer-implemented method of optimizing a design in a time multiplexed programmable logic device comprising: (a) identifying a micro cycle; (b) identifying all look-up tables (LUTs) from a list of LUTs of said design that may be scheduled in said micro cycle; (c) ordering said LUTs in priority order; (d) selecting the M LUTs with the highest priority, wherein M is the number of real LUTs in said programmable logic device; (e) labeling said M LUTs with the current micro cycle number; (f) removing said M LUTs from said list; (g) identifying the next micro cycle; and (h) if un-labelled LUTs exist, then repeating (a)-(h), otherwise exiting said computer-implemented method.
Claim 2
Dependent Claim 110 words
A computer-implemented method of optimizing a design in a time multiplexed programmable logic device comprising: (a) identifying a micro cycle; (b) identifying all look-up tables (LUTs) from a list of LUTs of said design that may be scheduled in said micro cycle; (c) ordering said LUTs in priority order; (d) selecting the M LUTs with the highest priority, wherein M is the number of real LUTs in said programmable logic device; (e) labeling said M LUTs with the current micro cycle number; (f) removing said M LUTs from said list; (g) identifying the next micro cycle; and (h) if un-labelled LUTs exist, then repeating (a)-(h), otherwise exiting said computer-implemented method.
Claim 3
Dependent Claim 17 words
The computer-implemented method of claim 1 wherein (c) includes identifying the LUTs with the earliest latest-possible schedule.
Claim 4
Dependent Claim 22 words
The computer-implemented method of claim 1 wherein (c) includes identifying the LUTs having input nets in which all LUTs are already scheduled.
Claim 5
Dependent Claim 30 words
The computer-implemented method of claim 1 wherein (c) includes identifying the LUTs that include a pin on a net that has had at least one of its destination instances scheduled.
Claim 6
Dependent Claim 38 words
The computer-implemented method of claim 1 wherein (c) includes identifying the LUTs that will complete a net that may be introduced in said micro cycle by the addition of a LUT earlier in a list of said LUTs.
Claim 7
Dependent Claim 39 words
The computer-implemented method of claim 1 wherein (c)includes identifying the LUTs that include a pin on a net that may be introduced in said micro cycle by the addition of a LUT earlier in a list of said LUTs.
Claim 8
Dependent Claim 137 words
A computer-implemented method of optimizing a design in a time multiplexed programmable logic device comprising: (a) identifying a micro cycle; (b) identifying all look-up tables (LUTs) from a list of LUTs of said design that may be scheduled in said micro cycle; (c) ordering said LUTs in priority order; (d) selecting the a LUT with the highest priority; (e) identifying whether the number of selected LUTs is equal to M, wherein M is the number of real LUTs in said programmable logic device; (f) repeating (d) and (e) until the number of selected LUTs is equal to M; (g) labeling the M LUTs with the current micro cycle number; (h) removing said M LUTs from said list; (i) identifying the next micro cycle; and (j) if un-labelled LUTs exist, then repeating (a)-(j), otherwise exiting said computer-implemented method.
Claim 9
Dependent Claim 137 words
A computer-implemented method of optimizing a design in a time multiplexed programmable logic device comprising: (a) identifying a micro cycle; (b) identifying all look-up tables (LUTs) from a list of LUTs of said design that may be scheduled in said micro cycle; (c) ordering said LUTs in priority order; (d) selecting the a LUT with the highest priority; (e) identifying whether the number of selected LUTs is equal to M, wherein M is the number of real LUTs in said programmable logic device; (f) repeating (d) and (e) until the number of selected LUTs is equal to M; (g) labeling the M LUTs with the current micro cycle number; (h) removing said M LUTs from said list; (i) identifying the next micro cycle; and (j) if un-labelled LUTs exist, then repeating (a)-(j), otherwise exiting said computer-implemented method.
Claim 10
Dependent Claim 24 words
The computer-implemented method of claim 1 further including optimizing said labeling by moving at least one additional LUT into at least one micro cycle.
Claim 11
Dependent Claim 24 words
The computer-implemented method of claim 7 further including optimizing said labeling by moving at least one additional LUT into at least one micro cycle.

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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) 2000-12-22 2001-06-23 2001-12-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-12-22 2005-06-23 2005-12-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-12-22 2009-06-23 2009-12-23 $7700.00 Window Closed / Lapsed

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