Background Theory > The Origin

In electronic design, the schematic coordinate origin refers to the reference point from which the X and Y coordinates of schematic elements, such as components, wires, and text, are measured. It is essentially the starting point of the coordinate system used within the schematic design.

The coordinate origin is typically denoted by a small cross-hair or marker on the schematic canvas. When elements are placed on the schematic, their positions are defined by their X and Y coordinates relative to this origin.

The choice of the coordinate origin is arbitrary and does not affect the functionality of the schematic. However, it can be useful for ensuring consistency and ease of working on the design, especially when there are multiple sheets or when the design is transferred between different tools.

Some considerations regarding the schematic coordinate origin include:

•Consistency: In a multi-sheet design, it is helpful to use the same coordinate origin across all sheets. This consistency makes it easier to align elements between sheets and maintain a coherent layout.

•Tool Compatibility: When sharing schematics between different Electronic Design Automation (EDA) tools, it is essential to be aware of how each tool handles the coordinate origin. Some tools may use different default origins or have specific preferences for defining the origin.

•Component Placement: The choice of the coordinate origin can influence how components are placed and arranged within the schematic. Designers may find it more convenient to have the origin at a specific location that corresponds to a critical component or functional block.

•Grid Alignment: The coordinate origin often aligns with the grid lines, which can help with precise component placement and alignment to the grid.

Designers can typically adjust the schematic coordinate origin in their EDA software tools. This capability allows them to set the origin at a location that makes sense for their particular design needs. Additionally, DEX offers the ability to set a "snap" feature, such as "Snap to Grid" or "Snap to Guides," to help align elements to the grid or user-defined guides relative to the chosen coordinate origin.