What is Hardware Version Control?

Hardware version control is the process of tracking and managing changes to hardware designs over time, similar to how software version control systems like Git track changes to code. A hardware version control system (VCS) allows hardware engineers to:

• Store design files in a centralized repository
• Track changes and who made them
• Revert to previous versions if needed
• Branch and merge different versions
• Collaborate with team members

Some popular hardware VCS options include:

VCS	Description
Altium 365	Cloud platform for PCB design with built-in version control
Altium Concord Pro	On-premise VCS for Altium Designer
Upverter	Browser-based PCB design tool with real-time collaboration and version control
GitHub	Git-based VCS that can be used for hardware design files

Benefits of Using a Hardware VCS

Implementing version control for hardware designs provides several key benefits:

1. Full Change History and Traceability

With a VCS, every change made to the hardware design is recorded. You can see exactly what was changed, who made the change, and when it happened. This provides full traceability, making it easy to track down issues and understand how the design has evolved over time.

2. Simplified Collaboration

Version control enables multiple engineers to work on the same design simultaneously without overwriting each other’s changes. Users can check out files, make changes, and merge their work back into the main design. The VCS handles any conflicts and keeps everything in sync.

3. Release Management

A VCS makes it easy to manage different versions and releases of a hardware design. You can tag specific versions, create release branches, and keep a stable production version separate from ongoing development work. Rolling back to a previous release is simple if issues are found.

4. Intellectual Property Security

Storing design files in a centralized VCS repository keeps valuable IP secure and controlled. Access can be restricted to authorized users only. File versioning prevents accidental overwrites and deletions. Regular backups ensure data is protected.

Hardware VCS Best Practices

To get the most value out of a hardware VCS, there are several best practices to follow:

1. Store All Design Outputs

Check in all the key outputs from your hardware design process to the VCS:

• Schematics
• PCB layout files
• Bill of materials (BOM)
• Datasheets
• Firmware source code
• Documentation

This ensures every artifact is versioned and kept in sync. For binary files that can’t be diffed and merged (like PCB layouts), use the VCS to track the file versions even if the contents can’t be compared.

2. Establish a Clear Folder Structure

Organize your VCS repository with a clear folder structure that separates different types of design files. For example:

/hardware-project
  /pcb
    /lib
    /packages
    board.pcb
    schematic.sch
  /docs
  /datasheets
  /firmware
  BOM.xlsx
  README.md 

Agree on a standard structure with your team and stick to it across projects. Use the VCS branching features to manage variants, rather than copying folders.

3. Integrate with Issue Tracking

Choose a VCS that integrates with your team’s issue tracking or project management system (like Jira). Reference issue IDs in your VCS commit messages to keep design changes connected to their original requirements or bug reports. Some tools can automatically update issues and requirements docs based on VCS commits.

4. Automate Releases and Notifications

Set up continuous integration to automatically generate release outputs (Gerbers, PDFs, BOMs, etc) whenever a new version is tagged in the VCS. Notify stakeholders when new releases are available. Automating these steps saves time and keeps everyone in sync.

5. Define Merge and Review Processes

Establish standard processes for reviewing and merging changes to the hardware design. Designate maintainers who are responsible for approving merge requests. Use your VCS’s pull request and code review features to collaborate on changes before merging. Automated checks (like ERC and DRC) can be run on each merge to catch issues early.

6. Keep the Repository Clean

Avoid checking in unneeded outputs or intermediate files to the VCS. Use a .gitignore or similar mechanism to exclude temporary files and generated outputs from version control. Checking in only the key source design files keeps the repository clean and focused.

Challenges of Hardware Version Control

While very valuable, hardware version control does have some challenges compared to software:

Binary Files

Many hardware design output files (schematics, PCB layouts, etc) are in binary formats that can’t be easily diffed or merged. The VCS can’t show detailed changes within these files or resolve conflicts. Merging has to be done manually in the design tool.

Large File Sizes

Binary design files tend to be much larger than source code files, taking up significant VCS storage space. Checking in generated gerber files, 3D models, and other manufacturing outputs multiplies the repository size. Cloud-based VCS solutions are better suited to handle large files.

Limited Tool Integration

Not all PCB design tools have robust VCS integration. Many require manual steps to check files in/out of version control. Others aren’t compatible with branching and merging workflows. Using VCS features may require adjusting your design flow to fit the tools.

Despite these challenges, a well-implemented hardware VCS provides significant benefits in traceability, collaboration, and quality. With the right practices and tools, version control is an essential part of the modern hardware development process.

Frequently Asked Questions

What types of files should be stored in a hardware VCS?

All the key design outputs should be versioned, including:
– Schematics
– PCB layout files
– Bill of Materials (BOM)
– Datasheets
– Firmware source code
– Documentation

Can I use GitHub for hardware version control?

Yes, GitHub can be used as a VCS for hardware projects. It provides the same benefits of tracking changes, branching, and merging as it does for software. However, GitHub may not handle large binary design files as well as purpose-built hardware VCS tools.

How often should I commit changes to the VCS?

Aim to commit changes frequently, at least once a day when actively working on a design. This keeps the VCS up to date and makes it easier to track changes. Avoid one large commit at the end of a project.

How do I resolve conflicts in binary design files?

Because schematics and PCB layout files are binary, the VCS can’t automatically merge changes from different versions. Resolving conflicts has to be done manually in the PCB design tool, with the designer carefully comparing the differences and picking which changes to keep.

What’s the best VCS tool for hardware design?

The best VCS tool depends on your specific needs and design tools. Cloud-based lifecycle management platforms like Altium 365 work well for collaborative teams. More generic VCS tools like GitHub and GitLab can be used for open source hardware projects or to store design outputs. The key is picking a VCS that integrates with your design flow and is actually used consistently by the whole team.