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Boundary Netlist Based Accurate Time Budgeting With Reduced Runtime

IP.com Disclosure Number: IPCOM000220218D
Publication Date: 2012-Jul-25
Document File: 4 page(s) / 336K

Publishing Venue

The IP.com Prior Art Database

Abstract

Hierarchical designs require a timing budgeting approach for interface timing closure. The existing time budgeting approach doesn’t ensure optimal time budgeting of the interface path and other more critical timing paths due to tool capacity issues. This results in unbalanced IO constraints, which takes more time to conclude. Moreover, it also results in an increase in overall area and power. We have made an effort to solve the above problems. We propose a solution that can be used early in the design cycle yet provide accurate timing budgets. This helps in finalizing the IO constraints at the initial stage.

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Boundary Netlist Based Accurate Time Budgeting With Reduced Runtime

Introduction

                Hierarchical designs require a timing budgeting approach for interface timing closure. The existing time budgeting approach doesn’t ensure optimal time budgeting of the interface path and other more critical timing paths due to tool capacity issues.  This results in unbalanced IO constraints, which takes more time to conclude.  Moreover, it also results in an increase in overall area and power.

            We have made an effort to solve the above problems. We propose a solution that can be used early in the design cycle yet provide accurate timing budgets.  This helps in finalizing the IO constraints at the initial stage.

Boundary Netlist Based Accurate Time Budgeting

Our approach is based on reducing unnecessary logic; that is logic not required for block boundary optimization.  This reduces the design to even less than 10% of its size, which when optimized and budgeted will generate more accurate time budgeting.  IO constraints generated this way can be finalized at pre-synthesis stage.

The basic flow for this approach is shown below.

 

STEP 1: Creating Boundary Netlist

Boundary netlist is the form of netlist in which only that logic is present which interacts with block boundary.  All other logic not interacting with the block, whether present inside the block or at the chip top level, is removed.  Fig. 1 shows the difference between the flat netlist and boundary netlist

Depending on the design,...