PCB Design Blogs

This post is for those of you who have been creating logical designs and boards for a while. In most cases, a new product or design doesn’t require every component or module to be made from scratch. Most standard components are reused and, at times, a large part of the circuitry and logic gets reused as-is. This helps quick start a new design. You start with an existing design, or add parts of existing designs, customize as per your requirements, and a new initial design is ready for fine-tuning.

When you reuse a design or a section of an older design, that you know has been tested and approved for production, you are sure that, that part of the larger schematic works and will not spring any surprises. It’s as simple as selecting a component from a library and placing it in your design. Add connections and it all works.

Allegro^® System Capture includes many ways to reuse existing libraries and designs. To recap how Allegro System Capture supports creating designs that access libraries authored in Design Entry HDL(DE-HDL) and OrCAD^® Capture seamlessly, visit ASCENT: Ready, Steady, Design ... Even With Existing Libraries. Let’s now see how you can reuse designs.

In Allegro System Capture, reuse possibilities go from simple copy and paste across designs, to importing designs as blocks, sheets, and even creating new designs that are based on existing designs. Reuse also extends to layout files. You can create system-level designs that build upon pre-existing boards.

Creating Projects Based on Existing Designs 

Allegro System Capture is fully compatible with DE-HDL and OrCAD Capture. You can select a design created in any of these design authoring applications and create a new Allegro System Capture project.  

This creates a new design in Allegro System Capture.

Moving on, let’s see how parts of a design can be imported. Before that, a reminder: Only designs that have compatible grid settings and the exact same pin-to-pin spacing, can be imported or pasted into an existing Allegro System Capture design. 

Importing Sheets from Other Designs 

To import sheets, follow the steps depicted in the image:

Constraints and variants are not imported when importing sheets.  For including them, you can either create a new design or import the design as a block.

Importing Other Designs as Blocks 

Designs created in other applications as well as Allegro System Capture can be imported into an Allegro System Capture project.  To import a block, follow the steps depicted in the image:

When you import a block:

• All its subblocks are also imported. If any block already exists in the target design with the same names, Allegro System Capture does not import the block.
• All the design-level information, such as packaging information, constraints, block symbol, and variant data, is also imported. This data can easily be reused in the target design.
• If the source design does not have a symbol, a schematic symbol for the block is generated. This schematic symbol is available in Allegro System Capture for instantiating the block.

Copy Pasting Across Designs 

You can copy circuitry and sheets in one Allegro System Capture design and paste them into another open design. All you need to ensure is that both designs are set up for the same library type: Allegro Unified, DE-HDL, or OrCAD Capture. The next two images show circuitry and pages being copied across designs, respectively.

System-Level Designing with Existing Boards

With any of the system design licenses, you can build a system using multi-board connectivity.  This is also called the bottom-up flow. Existing designs, or boards, are reused as subsystems to create a new system. The existing layout files are instantiated as blocks that represent PCB projects, and then interconnectivity between the subsystems is defined.  The image shows two representative subsystems connected by a NetGroup.

Creating Designs Based on Templates

If you are working in an enterprise where multiple designers connect to the same server and designs get stored on the central server, Allegro System Capture can help you create new designs based on templates. Templates can include pre-defined project settings, such as Table of Contents and Page Borders, or be complete designs.  

From the Start Page, you can create a new design from scratch or create one based on a previously saved template.

These are the ways in which Allegro System Capture supports design reuse. Try them out and get your new design up faster.

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