Automated Stale NDR Detection for IC Timing Analysis
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Solution Overview
Problem
The conventional process for selecting Nominal Delay Rules (NDRs) in integrated circuit design is inadequate, particularly for large designs and dynamic environments, as it ignores the integrity and generation dates of NDR types, leading to potential inaccuracies and complications.
Innovation Solution
A method that automatically selects the most recent delay-definition data structures for input into the timing analysis process, rejecting any with missing or corrupted components, ensuring that only up-to-date and valid data is used for timing performance evaluation across hierarchical boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional NDR selection process is used, then the timing analysis can be performed with available data structures, but the accuracy and reliability of timing analysis deteriorates due to use of stale or corrupted NDRs
Solution Approach 1:
The patent applies preliminary action by checking the integrity and recency of NDR data structures before they are used in timing analysis. The system performs validation checks on compile dates and data completeness in advance, rejecting stale or corrupted NDRs before they can compromise the timing analysis results.
Solution Approach 2:
The patent implements feedback by establishing a selection process that evaluates NDR data structures based on their compile dates and integrity status. The system provides feedback by selecting only the most recent valid NDRs for each macro, ensuring that timing analysis uses current and reliable data while automatically excluding outdated or corrupted versions.
2Manufacturing precision
If all NDR types are considered for selection, then the choice of NDR for timing analysis becomes more complex, but the accuracy of timing analysis improves due to broader selection options
Solution Approach 1:
The patent applies parameter changes by using the compile date as a key parameter for NDR selection. Instead of complex multi-criteria evaluation, the system transforms the selection problem into a simple comparison of date parameters, choosing the NDR with the most recent compile date that meets integrity requirements.
Solution Approach 2:
The patent extracts only the essential selection criterion (compile date) from the complex set of NDR properties. By focusing extraction on the date parameter and integrity status, the system simplifies the selection process while maintaining accuracy, eliminating the need to evaluate multiple competing factors.
3Productivity
If manual selection of NDRs is performed, then the selection process allows human judgment and flexibility, but the productivity and speed of design process decreases
Solution Approach 1:
The patent implements self-service by enabling the NDR selection process to perform automatically without human intervention. The system independently evaluates compile dates, validates data integrity, and selects appropriate NDRs based on predefined criteria, eliminating the need for manual review while ensuring consistent and reliable selection.
Solution Approach 2:
The patent replaces the mechanical human judgment process with an automated computational system. Instead of manual evaluation of NDRs, the system uses algorithmic comparison of compile dates and automated integrity checks, substituting human cognitive processes with mechanical computation to achieve both speed and consistency.
4Productivity
If stale NDRs are used in timing analysis, then the design process can proceed without delays, but the accuracy of timing performance evaluation deteriorates
Solution Approach 1:
The patent applies preliminary action by validating the recency of NDR data structures before they are incorporated into timing analysis. The system checks compile dates in advance and prevents the use of stale NDRs, ensuring that only current data is used while maintaining design process momentum through automated validation.
Solution Approach 2:
The patent implements dynamics by making the NDR selection process adaptive to changing data states. The system dynamically evaluates compile dates and automatically updates the selection of NDRs based on their recency, ensuring that timing analysis always uses the most current available data without requiring manual intervention.
Data Source
AI summary
Best and most recent NDR types are selected for all RLM's in a design in order to achieve timing closure. The selection employed uses two levels of filtering to examine the NDR types for each RLM, and based on the outcome of the filtering selects the most appropriate NDR type for input to the timing analysis. In one arrangement, the selection scheme is completely automated and is performed at the beginning of a timing analysis via script-driven processes.