Not That Much Force: Software for Updating PCB Layouts and Avoiding Redesigns

The other night I went to see the new Star Wars movie, “The Last Jedi," and although I really enjoyed the movie I found myself laughing out loud during one sequence. I wasn’t laughing because of the humor of the movie, or a silly looking alien—there were plenty of those to go around already. Instead I was laughing because for one brief sequence they showed some electronic circuitry that appeared to be composed of what looked like thru-hole resistors and capacitors. Seriously? These guys are flying around in space ships, going faster than the speed of light, and shooting lasers at each other; yet, their PCB’s need repairing in order to fix some thru-hole resistors?

There are three things here to keep in mind: first is that it is set, “A long time ago, in a galaxy far far away,” so maybe that explains the 1960’s era technology. Second, the resistance fighters are trying to mount their war on the cheap, so perhaps they are getting all of their technology online at a discount surplus space junk dealer. And third… it’s just a movie.

This got me to thinking about older printed circuit board designs from other CAD systems that are still in use, but whose layouts need to be updated. Sometimes an attempt will be made to reverse engineer old Gerber files in a CAM tool. Though most of the time, the job will be too complex for that and the PCB will get completely redesigned. There is a third option though, and that is to import and translate the old CAD data into your current system for the updates and changes that are required. Understanding these different options and will leave you confident in whether translating old CAD data is exactly what you need to update those old designs.

The Force Awakens: Reverse Engineering through Software for PCB Layouts

There have been a few times where I have had to take old Gerber files and pull them into a computer-aided manufacturing (CAM) system for edits. If the only change that is needed is an updated document number, then this isn’t too bad of a chore. Unfortunately, most PCB design updates involve a lot more work than a simple text change.

Imported Gerber files will build a database in the CAM system composed of lines, circles, squares, and polygons. The more complex the CAM system is, the more those primitive shapes will be converted into complex polygon shapes with attributes. Although this is helpful, you have to remember that this is a CAM database and not a PCB design database. In order to create a fully functional PCB database, you would need a netlist that you could synchronize with the CAM database to assign net intelligence to the different primitive shapes. As you can guess, this is a very complex task assuming that your CAM system even has this capability.

Without the net intelligence, your design will not have the functionality that you have come to expect with standard PCB layout systems. You will not be able to place or route them. Instead, you will have to move the pad shapes that comprise a regular PCB component together and then manually draft the lines and polygons to recreate the routing and the area fills. Moving or creating drill holes is another painful operation. Trying to update a PCB design in a CAM tool is extremely difficult, and you will be doing all of this work without your regular PCB DRC’s and constraints. Now, imagine doing all of this in the middle of a space battle.

We Need More Drones! What About Complete Redesign?

Due to the difficulty of reverse engineering a design from Gerber files, most companies that I know of will do a complete re-design from scratch. This will ensure that the design is done in the current layout tools using the most up-to-date data available. There are some problems though that should be considered first before going in this direction:

• Time: Plane and simple, doing a complete redesign is going to take the time of a new design, not a design update.
• Missing data: Do you have a complete set of documentation and data from the original design? Does your current CAD system have the same information as the original system did? You find yourself spending more time trying to track down some of these details than you expected.
• Test and qualifications: Depending on the application, a brand new circuit board may need to go through more testing and qualifications than what would normally be required for a simple design update.

PCB Layout Software that Translates Your Older Designs

Translating older design databases from a different PCB CAD system into your current layout tools is a great alternative from reverse engineering or completely re-designing a board. Make no mistake though, translating design databases is an advanced CAD function. To badly paraphrase Han Solo; “Translating design databases ain’t like dusting crops boy!” You will have to make sure that your settings are correct in order to both properly translate the design and synchronize to your libraries. But once you have the translator set up, the benefits will far outweigh the effort. Here are a few of the advantages that you will enjoy:

• Original components are maintained: Those components that the design originally used are usually translated along with the design. This allows you to re-populate them into your current if needed, and it will retain any components that were altered for a specific purpose.
• Critical part placement and routing are retained: This will preserve those critical elements of the design that were so carefully laid out initially.
• Design updates and changes can be done quickly: Without the need to completely redesign the board or reverse engineer it, simple design updates are accomplished very quickly with little effort.

Using database translators can solve many of the problems faced previously. They will allow you to avoid the time, complexities, and problems of both reverse engineering and completely redesigning older PCB designs.

Finding PCB design software with multiple database translators to help you to make short work of what would otherwise be a difficult database update isn’t as hard as stopping the Empire. If you’re looking to set yourself up for long-term success, then Altium Designer^®’s capability of translating your older design databases directly into the layout software will give you greater flexibility to handle all of your company’s PCB design needs.

Would you like to find out more about how Altium can help you to translate your older PCB design databases? Talk to an expert at Altium.