Setup the Schematic Editor

Before reading further, you can watch the companion video for this topic. In it, I demonstrate how to configure the schematic editor in KiCad, import the reference design’s net classes, and verify grid and formatting settings that match the LattePanda Mu Carrier board.

Introduction

This guide explains how to set up the schematic editor for your LattePanda Mu Carrier project in KiCad 9.
The schematic editor configuration includes importing net classes, assigning them appropriately, and adjusting layout parameters such as grid spacing and text formatting.

There are two methods to do this:

1. The slow way, where you manually recreate each net class and assignment.
2. The fast way, which imports all schematic settings directly from the LattePanda Mu Carrier reference project.

In this guide, we will use the fast way, which saves time and ensures accuracy by replicating the tested configurations from the reference design.

Setting Up the Schematic Editor

Open your KiCad project and launch the Schematic Editor.  From the top menu, open the Schematic Setup.

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Here, you will define or import net classes—groups of nets that share specific electrical and routing characteristics such as width, clearance, and impedance.

In the schematic setup window, click on Import Settings from Another Project.
Select the LattePanda Mu Carrier reference project (LattePanda-Mu-Lite-Carrier.kicad_pro) that you downloaded earlier from GitHub, located under:

/Electricals/Examples/LattePanda-Mu-Lite-Carrier/

Once imported, all predefined net classes and their assignments from the reference design will appear in your project.
This process copies not only the class names but also their trace width, clearance values, and associated net assignments—saving you considerable setup time.

Net Classes Overview

The imported net classes from the LattePanda reference design define how specific groups of signals should be treated during routing.
They are particularly important in high-speed PCB design because each interface—USB 3, HDMI, Ethernet, PCIe—has different impedance and spacing requirements.

When you begin adding symbols and drawing connections, the schematic editor will automatically apply the correct class to each net based on its name or pattern.
For instance, nets beginning with MDI are associated with the 100Ω class used for Gigabit Ethernet differential pairs.
Similarly, USB and HDMI nets belong to the 90Ω class to maintain consistent signal impedance during routing.

Grid and Formatting Preferences

After importing net classes, verify your schematic editor settings to ensure consistency with the LattePanda reference design.
The grid spacing used in the reference project works well for this design’s component pin pitch and schematic density. In KiCad, go to:

Preferences → Schematic Editor → Grid and Units

Set the grid to 1.27 mm, and confirm that the unit system is set to millimeters.
This ensures that symbol placement aligns correctly and that schematic readability is consistent with professional design standards.

You may also adjust text size and formatting under Display Options, particularly if your schematic is dense. Smaller font sizes improve clarity when documenting complex high-speed designs.

Summary of the Setup Process

The schematic editor setup is now complete. You have:

• Imported the net classes and assignments from the LattePanda Mu Carrier reference project.
• Verified the grid and formatting settings for clear and consistent schematic capture.
• Confirmed that impedance-controlled net classes (90Ω and 100Ω) are correctly defined for high-speed interfaces.

This configuration ensures that all signals—especially differential pairs such as USB, HDMI, and Ethernet—will maintain their required electrical properties during layout and routing.

Conclusion

By importing the schematic settings from the LattePanda Mu Carrier reference design, you have aligned your custom project with proven, industry-validated electrical parameters.
You now have the correct net classes, grid, and text settings in place, allowing you to proceed confidently with schematic creation.

In the next guide, we will create the hierarchical schematic sheets, where the system’s power, interfaces, and control circuits will be organized logically before detailed wiring begins.

Ready for the next tutorial in this series? Here's the next one, or choose an alternative from the list of articles in the side bar. There's also lots of interesting article in our Blog. where you can read about off-grid communication technologies, electronics test equipment, course updates, and much more.