
- •Contents
- •Introduction
- •About These Application Notes
- •What Is a Cell?
- •Cell Interconnect Delays
- •What Is Delay Back Annotation?
- •What Is Delay Calculation?
- •Prerequisites and Related Reading
- •Creating a Back Annotator
- •The Programming Language Interface (PLI) Mechanism
- •PLI Access Routines
- •Access Routine Families
- •Required UTILITY Routines
- •Access to Timing Information
- •Effect of Source Protection
- •Where to Look for More Information
- •Back Annotating Delays
- •Examples Used in This Chapter
- •Retrieving a Handle to the Object Associated with the Delay
- •Retrieving a Handle to a Net
- •Retrieving a Handle to a Module Path Delay
- •Retrieving a Handle to a Timing Check
- •Annotating the Delay
- •Determining How and Where to Place Delays
- •Annotating to Cells with Path Delays
- •Annotating to Cells with Lumped or Distributed Delays
- •Libraries with Mixed Cell Timing Descriptions
- •Annotating to Timing Checks
- •Calculating Delays
- •Examples Used in This Chapter
- •Scanning Cell Instances Within the Design
- •Determining the Scope of the Delay Calculation
- •Scan Methodology
- •Scanning Objects Within the Cell Instance
- •Relationship to Modeling Methodology
- •Scanning Path Delays
- •Scanning Cell Output Ports
- •Libraries with Mixed Cell Timing Descriptions
- •Types of Data Needed
- •Coding Data into Cell Descriptions (Attributes)
- •Retrieving Cell I/O Load Factors
- •Load Due to Interconnect Wire
- •Calculating and Annotating the Delays
- •Calculating the Delays
- •Annotating the Delays
- •Example Listings
- •Delay Back Annotators
- •Cell Output Nets to Lumped or Distributed Delay Cells
- •Interconnect Nets to Lumped or Distributed Delay Cells
- •Cell Output Nets to Path Delay Cells
- •Interconnect Nets to Path Delay Cells
- •Delay Calculators
- •Creating and Extracting Data From a Hash Table
- •Random Cell Scan and Cell Output Nets
- •Random Cell Scan and Cell Interconnect Nets
- •Delay Calculation Driven by Cell Output Nets
- •Delay Calculation Driven by a Cell Interconnect Nets
- •Index

Back Annotation and Delay Calculation
Introduction
Figure 1-2 Veritool simulation environment with an integrated delay calculation facility including optional back annotation functionality
Design database
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design source |
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extraction |
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utility |
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Compilation |
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Back annotation file |
Back annotation and |
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delay calculation |
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structure |
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parameters) |
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Veritool |
Prerequisites and Related Reading
Before reading this document, it is important that you understand several topics related to delay back annotation and delay calculation. A list of these topics is provided in Figure 1-3 on page 11 , along with references where further information can be obtained on each item. If necessary, please review the appropriate topic(s) before continuing with document.
Figure 1-3 Where to find prerequisite information
Topic |
Reference |
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Verilog simulation and hardware description |
Verilog-XL Reference Manual |
language (HDL) syntax |
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PLI—overview of access routines and how to |
PLI 1.0 User Guide and Reference |
create user-defined system tasks |
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C programming |
Any C reference manual or instructional |
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guide |
October 2000 |
11 |
Product Version 3.2 |

Back Annotation and Delay Calculation
Introduction
Topic |
Reference |
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ASIC cell-based design methodology |
Introductory literature on cell-based design, |
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ASIC cell library data books |
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October 2000 |
12 |
Product Version 3.2 |