Allegro Front to Back User Guide

Allegro Front-to-Back User Guide Designing Layout October 2019 52 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. routing layers if the design is too dense to complete or you might need to delete layers because of an Engineering Change Order (ECO). The layout cross section consists of the ordered layers of your layout, including the information about their type, thickness, electrical behavior, and shielding. You also specify whether to photoplot positively or negatively when you set up your cross section. For more information, refer to the Capturing Physical Constraints chapter. Defining Constraints When you start a new design, you set design rules and constraint values that conform to your design rules. You can set the values using the constraint dialog boxes. A constraint is a user-defined limit applied by design rule checking (DRC) to one or more physical elements in a design. When you define and apply a constraint value, Allegro PCB and Package adheres to that constraint in automatic and interactive processing and flags violations with DRC markers. You can think of a constraint as a bundled set of properties. Allegro PCB and Package provides a set of predefined design rule types, each with its own descriptive name; for example, Line to Pin Spacing and Minimum Line Width. Placement Allegro PCB and Package provides a variety of interactive and automatic features for placing components and swapping pins, functions (gates, inverters, or logical elements within a packaged component), and components. You can use interactive placement to place all components individually, or you can place components of the same type during one pass. In automatic placement, Allegro PCB and Package places components automatically based on controls that you set before starting automatic placement and by assigning certain placement properties that restrict or influence component positioning and part packaging. Routing The next phase in the PCB flow after placing the components on the board is routing the connections. The Allegro PCB Designer Routing Option is tightly integrated with the PCB Editor. Through the Routing Option interface, all design information and constraints are automatically passed

• Cover
• c contents - Contents
• Preface
• About the Front-to-Back Flow
• How This Book is Organized
• Creating and Managing Libraries
• Allegro Front-end Tools Libraries
• Library Structure
• Creating and Managing Libraries
• OrCAD Libraries
• Capturing Logical Design
• Creating Project Using Allegro Tools
• System Capture
• You can also perform other page manipulation operations, such as creating a new page or deleting an existing page from the Project viewer. You can drag and move the pages up and down to change their order in the Project viewer.
• Allegro Design Entry HDL
• Creating Project Using OrCAD Capture
• Creating a Schematic
• Designing Schematic Using System Capture
• Creating Schematic Using OrCAD Capture
• Capturing Logical Designs using DE-HDL
• Capturing Logical Design Constraints
• Why Constraint Manager?
• Using Constraint Manager with Design Capture Tools
• All the constraints are stored in the Constraint Manager Database (CMDB) and saved in the dictionary and constraints file designname.dcf.
• Constraints in System Capture
• Capturing Constraints in Design Entry HDL
• Capturing Constraints in OrCAD Capture
• Creating Variants of Your Design
• Managing Variants in System Capture
• Creating Variants using Variant Editor
• Getting Logical Design Ready for Physical Layout
• Preparing a System Capture Design for Physical Layout
• Preparing a DE-HDL Design for Physical Layout
• Exporting a DE-HDL Design
• Forward Mode
• Preparing an OrCAD Capture Design for Physical Layout
• Exporting an OrCAD Capture
• Annotating the Design
• Packaging Your Design (Advanced)
• Generating a Bill of Materials
• Updating the Schematic With the Changes in the Board
• Passing Properties from the Layout to Schematic
• Designing Layout
• Physical Layout using OrCAD PCB Editor
• Creating a Board Outline
• Creating Symbols and Padstacks
• Importing Logic
• Defining Layers
• Defining Constraints
• Placement
• Routing
• Design Synchronization
• Physical Layout using OrCAD Capture
• Preparing the Schematic for Layout
• Property Flow from Capture to PCB Editor
• Generating Initial Board File
• Backannotation from PCB Editor
• Running Design Rules Check - Physical Rules
• Capturing Physical Constraints
• Using Constraint Manager with PCB Editor
• Synchronizing Schematics and Boards
• Need for Synchronization
• Design Synchronization Tasks
• Feedback Mode