Altium Schematic Highlight Net

[Ailene Goldhirsh]

As the design builds up it quickly becomes dense and detailed - the schematic busy with wiring and the board a maze of connection lines and routed nets. To help bring clarity and visibility, the designer can apply color to the schematic wiring, PCB connection lines, and routing.

The ability to selectively override the color of specific nets is known as Net Color Override. Color can be applied to schematic nets and those color settings transferred to the PCB, or color settings can be applied directly in the PCB editor.

The image below shows a complex high-speed design using net color to help the designer easily identify groups of critical nets. Further down the page, there is an image that shows the same board with and without color on the routed nets.

Select a command indicating color or choose the Custom command to set the specific color you want to use for net highlighting using the standard Choose Color dialog that opens. Click on a pin, wire, bus or net identifier (net label, sheet entry, port, power port or offsheet connector) to apply the selected color to that net (or all the nets in a bus). The command remains active after clicking on the first net, ready to color subsequent nets in that same color if required.

When a color is applied to a net or a bus, it overrides any previous color setting. Note that net color settings cannot be undone, to remove a color setting use the Clear Net Color command, or the Clear All Net Colors command (View Set Net Colors sub-menu).

Because a net is a compiled object, determined from the current arrangement of wiring and net identifiers, the color setting for a net is not stored with the various objects placed on the sheets. The color settings are actually stored in the project file as a net-level setting and are applied on each schematic sheet after it is opened and the background compiler has compiled that sheet.

Net colors are always applied to the connection lines. Routed nets can be displayed either in layer color, or net color. The display of net colors in the PCB editor can be controlled at the individual net-level and also at the editor-level, more on this below.

When the design is transferred from the schematic into the PCB workspace, default color settings are applied to all nets. All of the net connection lines are assigned the default Connection Lines color, as defined in the System Colors section of the Layers & Colors tab of the View Configuration panel (L shortcut). Net colors defined in the schematic will override this default.

The default behavior for routed nets is to display them using the color of the layer that the routing objects have been placed on. You can also use the net color for routed nets, by enabling the Net Override Color feature for the required nets, and also for the PCB editor.

The PCB editor can display the override color in a variety of ways, including as a solid override of the chosen color, or in a number of different override patterns. This behavior is configured in the PCB Editor - Board Insight Color Overrides page of the Preferences dialog.

The Base Pattern option determines how the routing is displayed when you are zoomed in. The pattern options are included so that you can still see both the routing layer color and the override color. This is useful if you are tracing a net that is moving through the layers, and you also need to keep track of which layer it is currently on.

The image below shows how well multiple sets of critical nets in a high-speed PCB design stand out once they have been identified using different colors. In this example, the Zoom Out Behavior is set to Override Color Dominates. Hover the cursor over the image to show the same layer with Net Color Override disabled.

An excellent example of the net color override feature being used to easily identify classes of nets in a high-speed design, hover to switch off the override feature.
(image courtesy FEDEVEL Open Source, www.fedevel.com)

The features available depend on your Altium product access level. Compare features included in the various levels of Altium Designer Software Subscription and functionality delivered through applications provided by the Altium 365 platform.

I have a chip that I'm testing voltages on. I can highlight the chip by alt-clicking on it, at which point the pads are highlighted. At this point, is there a command to highlight everything these pads are connected to? As opposed to looking up each trace one by one in the schematic.

Right-click on component > Component actions > Select Component Nets (highlights all nets, routed or unrounted). Select Component Connections will only highlight physically routed connections from the component. This is explained in the Altium Documentation.

Altium provides various powerful cross-probing and cross-selecting capabilities enabling fast, efficient navigation between schematic and PCB design domains. The Cross-Probing and Cross Selecting features are powerful search tools to help locate objects in other editors by selecting the object in the current editor.

Cross-probing is used to point to a chosen object on the current document then "jump to" its corresponding counterpart in the target document. Between the PCB and schematic editors, full cross-probing support is provided for documents, components, buses, nets, and pins/pads(s). Literally, with a single click, you can select a supported object in either domain and see it highlighted in both.

Many of the features of Cross-Probing and Cross Selecting either require, or are more easily utilized, viewing both the schematic and PCB documents at the same time. You can view both documents at the same time by performing one of the following:

Cross-probing is a powerful searching tool to help locate objects in other editors by selecting the object in the current editor. There are numerous places you can cross probe in Altium Designer. For example, once you have launched cross probing from the PCB editor, you can click on a component on the PCB to display the same component on the schematic. Between the schematic and PCB editors, full cross-probing support is provided for documents, components, buses, nets, and pins/pads.

The cross-probing feature is accessed from either the schematic or PCB editor using the Tools Cross Probe command or by clicking the button from an editor's Standard toolbar.

The Continuous Mode allows you to stay in the source document while cross-probing to different objects on the target document. For this mode, ensure that the schematic and PCB documents are open side-by-side in the main design window.

After launching the cross-probe command by clicking Tools Cross Probe, the cursor will change to a cross-hair and you will be prompted to choose the object that you wish to navigate. Position the cursor over the required object within the design space and click or press Enter. The corresponding object will be highlighted on the target document.

After launching the cross-probe command by clicking Tools Cross Probe, the cursor will change to a cross-hair and you will be prompted to choose the object that you wish to navigate. Position the cursor over the required object within the workspace then Ctrl+click or press Ctrl+Enter. The corresponding object will be highlighted on the target document which will be made the active document.

Cross-probing also can be accomplished in various additional places in Altium Designer. These additional locations enable you to use the cross-probe function even as you are building your design without the need to use the Tools Cross Probe command.

You can cross probe from the Engineering Change Order dialog by right-clicking to access cross probe commands to locate the Reference component in the schematic or the target component in the PCB as shown in the image below:

You can use the Variant Manager or Variant Management dialog to cross probe to a chosen component on the schematic. Double-click on the component in the Variant Manager or Variant Management dialog or right-click, then select Cross Probe from the menu.

To cross probe to the schematic or PCB from the Differences panel (click the Explore Differences button in the Differences between dialog to access this panel), double-click on an entry in the panel.

To cross probe to a chosen component or net on the schematic or the PCB from the Projects panel, right-click on an entry in the Components or Nets sub-folder and then select the Cross Probe to Schematic or Cross Probe to PCB command.

After validating the schematic project, you can right-click then choose Cross Probe or double-click on an error message in the Messages panel to jump to that error condition on the schematic.

To cross probe to an object from the Constraint Manager, right-click on its entry, then choose the Cross Probe option from the context menu or select Cross Probe from a custom rule's menu.

This feature facilitates dynamic, bi-directional component cross-selection. It is used to select corresponding objects between PCB and schematic documents. In other words, when you select an object on the PCB document, the same object on the source schematic document is also selected, and vice-versa. It is an ideal tool for building a set of selected objects ready for a design action. For example, you might be looking at a number of components on the schematic and would like to locate them in the PCB editor space so you can position them on the board.

Clicking Tools Cross Select Mode from the main menus. This command toggles the feature on and off and the status of the command is displayed in the Tools menu. Cross Select Mode is enabled when a blue box appears around the Cross Select Mode icon in the Tools menu as shown in the image below.

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