Allegro Front to Back User Guide

Allegro Front-to-Back User Guide Designing Layout October 2019 55 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. Preparing the Schematic for Layout Before you design the physical layout of your schematic in PCB Editor, you should validate your design to ensure the that the object names used in schematic follow the object naming convention required in PCB Editor. This section list some of the recommendations or best practices to be followed in Capture to ensure that schematic is successfully exported to PCB Editor. Property Flow from Capture to PCB Editor When you netlist a Capture schematic, not all properties defined in Capture are transferred to PCB Editor. For a property to flow from Capture to PCB Editor it needs to be included in the configuration (.cfg) file. The configuration file specifies net, part (function), and component instance and component definition properties. This mapping determines what properties may be netlisted from Capture to PCB Editor or back annotated from PCB Editor to Capture. If a Capture property is not included in the configuration file it is not passed to PCB Editor. Similarly, if an PCB Editor property is not listed in the file, it does not get back annotated to Capture. How properties are netlisted from Capture to PCB Editor Not all properties in the configuration file show up as properties in PCB Editor. Some of these properties are used in generating portions of the netlist PST*.DAT files. In PCB Editor, component properties (package properties in Capture) take precedence over function properties (part properties in Capture). So in the netlist, a package property value is used if both a part and package have values for the same property. Capture always uses the occurrence values in the netlist. For a design, you can have multiple configuration files. Generating Initial Board File While netlisting a Capture schematic, if required, you can also generate initial board file by selecting the Netrev option in the PCB Editor tab of the Create Netlist dialog box. In order to generate PCB Editor board file, perform the steps listed in the Generating PCB Editor Netlist section to launch the Create Netlist dialog box and specify netlisting options. On successful netlisting, blank board file is opened in PCB Editor where you can place the parts and route your ratsnest.

• 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