What are DRU files?

DRU files are text files that contain a set of design rules for a specific PCB design. These rules define the minimum and maximum values for various parameters such as trace width, clearance, and hole size. By using DRU files, designers can ensure that their PCB layouts comply with the manufacturing requirements and industry standards.

Benefits of using DRU files

Using DRU files in EAGLE offers several benefits:

1. Consistency: DRU files ensure that all the design rules are applied consistently throughout the PCB layout, reducing the chances of errors and inconsistencies.
2. Flexibility: Designers can create custom DRU files for specific projects or manufacturing processes, allowing them to fine-tune the design rules according to their needs.
3. Time-saving: By using pre-defined DRU files, designers can save time and effort in setting up the design rules manually for each project.
4. Collaboration: DRU files can be easily shared among team members, ensuring that everyone is working with the same set of design rules.

New features in EAGLE V6 DRU files

CadSoft has introduced several new features and improvements in the DRU files for EAGLE V6. Some of the notable changes include:

1. Enhanced syntax

The syntax for defining design rules in DRU files has been improved in EAGLE V6. The new syntax is more intuitive and easier to read, making it simpler for designers to create and modify DRU files.

Example:

(width (min 0.2mm) (max 0.5mm))
(clearance (min 0.2mm) (max 0.5mm))

2. Support for multiple layers

EAGLE V6 DRU files now support the definition of design rules for multiple layers. This allows designers to specify different rules for different layers, such as top and bottom layers, inner layers, and power planes.

Example:

(layer TOP (width (min 0.2mm) (max 0.5mm)))
(layer BOTTOM (width (min 0.2mm) (max 0.5mm)))
(layer INNER (width (min 0.15mm) (max 0.3mm)))

3. Conditional design rules

DRU files in EAGLE V6 support conditional design rules, which allow designers to define rules that apply only under specific conditions. This feature is particularly useful for complex PCB designs with varying requirements.

Example:

(if (and (layer TOP) (net GND))
    (width (min 0.3mm) (max 0.8mm))
    (width (min 0.2mm) (max 0.5mm))
)

4. Improved error reporting

EAGLE V6 DRU files provide better error reporting when design rules are violated. The software now displays more detailed error messages, making it easier for designers to identify and fix issues in their PCB layouts.

How to create and use DRU files in EAGLE V6

Creating and using DRU files in EAGLE V6 is a straightforward process. Follow these steps to get started:

1. Open EAGLE and create a new PCB layout or open an existing one.
2. Go to “File” > “Open” and select “Design Rules” from the file type dropdown menu.
3. Browse to the location where you want to save the DRU file and give it a name.
4. Click “Open” to create a new DRU file or load an existing one.
5. Define your design rules using the new syntax and features provided in EAGLE V6.
6. Save the DRU file.
7. To apply the design rules to your PCB layout, go to “Tools” > “DRC” and select the DRU file you just created.
8. Run the Design Rule Check to ensure that your PCB layout complies with the defined rules.

Best practices for using DRU files

To make the most out of DRU files in EAGLE V6, consider the following best practices:

1. Start with a template: Use one of the provided DRU file templates as a starting point and modify it according to your specific requirements.
2. Keep it organized: Use comments and indentation to keep your DRU files organized and easy to read.
3. Test thoroughly: Always run the Design Rule Check after applying a new DRU file to ensure that your PCB layout complies with the defined rules.
4. Collaborate with your team: Share your DRU files with your team members to ensure consistency and collaboration in your PCB design projects.
5. Keep up with updates: Stay informed about the latest updates and improvements in EAGLE and DRU files to take advantage of new features and capabilities.

Frequently Asked Questions (FAQ)

1. Q: What is the difference between DRC and DRU files in EAGLE?
   A: DRC (Design Rule Check) is the process of verifying that a PCB layout complies with a set of design rules. DRU (Design Rule Unit) files contain the actual design rules that are used during the DRC process.

2. Q: Can I use EAGLE V5 DRU files in EAGLE V6?
   A: While EAGLE V6 is backward compatible with EAGLE V5 DRU files, it is recommended to update your DRU files to take advantage of the new features and syntax improvements in EAGLE V6.

3. Q: How can I share my DRU files with other team members?
   A: You can share your DRU files by saving them in a shared network location or by using a version control system like Git. Make sure to communicate any changes or updates to the DRU files with your team members.

4. Q: What should I do if I encounter errors while running the Design Rule Check with my DRU file?
   A: If you encounter errors, review your DRU file for any syntax mistakes or conflicting rules. EAGLE V6 provides detailed error messages that can help you identify and fix issues in your DRU files.

5. Q: Can I use conditional design rules in EAGLE V5 DRU files?
   A: No, conditional design rules are a new feature introduced in EAGLE V6 DRU files. To use conditional design rules, you need to update your DRU files to the new syntax and format supported in EAGLE V6.

Conclusion

CadSoft EAGLE V6 introduces new DRU files that offer enhanced syntax, support for multiple layers, conditional design rules, and improved error reporting. By using these new features, PCB designers can create more flexible and efficient design rules, ensuring consistency and compliance with manufacturing requirements. Following best practices and staying up-to-date with the latest improvements in EAGLE and DRU files can help designers streamline their PCB design process and collaborate effectively with their team members.

Feature	EAGLE V5 DRU Files	EAGLE V6 DRU Files
Enhanced syntax		✓
Multiple layer support		✓
Conditional rules		✓
Improved error reporting		✓

By leveraging the power of EAGLE V6 DRU files, PCB designers can create high-quality, error-free designs that meet the ever-increasing demands of the electronics industry. Whether you are a seasoned professional or a hobbyist, taking the time to learn and master the new features in EAGLE V6 DRU files will undoubtedly pay off in terms of design efficiency, reliability, and overall project success.