Port

Parent page: Schematic Objects

A placed Port

Summary

A port is an electrical design primitive. It is used to make an electrical connection between one schematic sheet and another sheet, or sheet symbol (through a corresponding sheet entry), in a design using multiple sheets (both flat and hierarchical designs). The name of the port defines the connection (i.e. a port on a schematic sheet connects to ports or sheet entries with the same name on other sheets in the project).

Availability

Ports are available for placement in the Schematic Editor only by clicking Home | Circuit Elements | 

Placement

After launching the command, the cursor will change to a cross-hair and you will enter port placement mode. Placement is made by performing the following sequence of actions:

• Click or press Enter to anchor the left-hand edge of the port.
• Move the cursor to adjust the length of the port as required, then click or press Enter to complete placement of the port.
• Continue placing further ports or right-click or press Esc to exit placement mode.

Additional actions that can be performed during placement – while the port is still floating on the cursor, and before its left-hand edge is anchored – are:

• Press the Tab key to access an associated properties dialog, from where properties for the port can be changed on-the-fly.
• Press the Alt key to constrain the direction of movement to the horizontal or vertical axis, depending on the initial direction of movement.
• Press the Spacebar to rotate the port counterclockwise or Shift+Spacebar for clockwise rotation. Rotation is in increments of 90°.
• Press the X or Y keys to mirror the port along the X-axis or Y-axis respectively.

Graphical Editing

This method of editing allows you to select a placed port object directly in the workspace and change its length, height, or location graphically.

When a port object is selected, the following editing handles are available:

A selected Port

• Click and drag A to change the length of the port.
• Click and drag B to change the height of the port.
• Click anywhere on the port – away from editing handles – and drag to reposition it. While dragging, the port can be rotated (Spacebar/Shift+Spacebar) or mirrored (X or Y keys to mirror along the X-axis or Y-axis respectively).
• The name for the port object can be edited in-place by:
  1. Single-clicking the port to select it.
  2. Single-clicking again (or pressing the Enter key) to enter the in-place editing mode. Sufficient time between each click should be given to ensure the software does not interpret the two single-clicks as one double-click (which would open the port's properties dialog).
  3. To finish editing in-place text, press the Enter key, or use the mouse to click away from the port.

Non-Graphical Editing

The following methods of non-graphical editing are available:

Via an Associated Properties Dialog

Dialog page: Port Properties

This method of editing uses the Port Properties dialog to modify the properties of a port object.

The Port Properties dialog

The dialog can be accessed during placement by pressing the Tab key.

After placement, the dialog can be accessed in one of the following ways:

• Double-click on the placed port object.
• Place the cursor over the port object, right-click then choose Properties from the context menu.

Via the SCH Inspector Panel

Panel page: SCH Inspector

The SCH Inspector panel enables you to interrogate and edit the properties of one or more design objects in the active document.

Port Actions

Right-clicking over a placed port will pop-up a context-sensitive menu, from which the following commands are available (on the Port Actions sub-menu) that act on that port (or all currently selected ports, where applicable):

• Jump to Sheet Entry <PortName> - use this command to jump to the port's corresponding sheet entry in the parent sheet symbol that references the sub-sheet on which the port resides.

• Toggle Port IO Type - use this command to toggle the I/O Type for the port.

The actual change depends on the current I/O Type as follows:

• Unspecified remains Unspecified.
• Output changes to Input.
• Input changes to Output.
• Bidirectional remains Bidirectional.

• Place Harness Connector of Type <HarnessConnectorType> - use this command to quickly place a harness connector (complete with respective defined harness entries) for connection to the port.

• Jump to Port <PortName> on <SheetName> - use this command to jump to another port with the same name on the indicated source schematic document.

Autosize

Doing things manually typically means having to expend additional effort. Of course, this gives you full control, but if an automated process can be put in place that is both fast and effective, its use can be of great benefit. With the port object, automation of port size can certainly have a positive impact on productivity.

To take advantage of the autosizing feature, enable the port's Autosize option. This can be done in either the Port Properties dialog or the SCH Inspector panel.

Autosizing in action. With the feature disabled (top) the port would have to be manually resized. When enabled (bottom), the port is automatically resized to accommodate the length of the new text.

If you change the font size, the autosizing feature has you covered. The height of the port will be resized to accommodate the text accordingly.

With autosizing enabled (bottom), the port will resize to fit the new text size.

Notes

1. When compiling a schematic or generating a netlist, the relationship between ports and sheet symbols is determined by the Net Identifier Scope chosen for the project. This scope is defined by setting the Net Identifier Scope option on the Options tab of the Options for Project dialog (Project | Content | Project Options). When set to Flat or Global, all ports with the same name within the same or different schematic documents are considered to be electrically connected. When set to Hierarchical or Strict Hierarchical, ports only connect vertically to their corresponding sheet entries. They do not connect horizontally to other ports of the same name.
2. The I/O Type option in the Port Properties dialog allows you to define the port's electrical type. Choose from either Input, Output, Bidirectional or Unspecified.
3. Should you need to negate (include a bar over the top of) a port name, include a backslash character after each character in the name (e.g., E\N\A\B\L\E\)
4. Port names are not used for naming nets. This means a system-generated net name will be used if no net label or power object is associated with that net.
5. When a Port is connected to a Signal Harness, the Port becomes a Harness object. By default, the Port will change color to match the color of the Signal Harness.
6. When a Port is connected to a Harness Connector by a Signal Harness, the Harness Type in the Port Properties dialog is automatically populated with the Harness Type of the Harness Connector. When a Port is connected to a Sheet Entry by a Signal Harness and the Sheet Entry has a Harness Type declared, the Port will become a Harness object and change to the color of the Signal Harness. If you move the Port away from the Harness Connector or the Sheet Entry, the Port will revert back to the default color.
7. By default, the font used for the port's Name follows the global document-level font set on the Sheet Options tab of the Document Options dialog (Project | Content | ). This can be overridden at the individual port-level using the control to the right of the Font label in the Port Properties dialog – allowing you to fully control the textual presentation of ports as needed.