Insert Bus Route

This option allows you to add multiple parallel tracks at the same time representing groups of signals such as memory routing, differential pairs and busses that need to be routed together.

Shortcuts

Default Keys: None

Default Menu: Insert

Command: Insert Bus Route

Locating this option

Available from: Insert menu > Insert Bus Route option

Using The Insert Bus Route Option

To aid this feature further, names of Busses in schematics, and the nets within them, are synchronised to the PCB design so that when adding PCB bus routes you can choose the signals required by using the schematic bus names. The most common use of bus routes is for a collection of nets in a schematic bus, or a collection of Differential Pairs, but can be used to take a group of any nets from one area of the board to another.

There are three phases to adding bus routes:

• Select the items (pads, vias, track ends) you wish to start from.
• Position a line of junctions at the start of the bus route that represent the start point of each track in the set.
• Add segments to define the path of the bus route.

Once added, the tracks in the bus route stick together, separated from each other by a constant gap which is usually defined by the track to track spacing rule, but can be changed to any other value. The bus route is gridded along its centre line, which may be the middle track if there is an odd number of tracks, or the centre of the gap in the middle if there are an even number of tracks. Subsequent editing of the tracks in a bus route will treat them as “one” and keep them locked together at the correct gap.

This section will guide you through the interactive bus routing tool.

Using Bus Route Mode

For more information about using the Bus Route mode click here.

Editing Bus Routes

After creating a bus route you can edit it again as a single item. When moving or editing any of the track segments in the bus route you will automatically edit the middle track (or the bus route centreline if there is an even number of tracks). The tracks will be updated to follow this line you are editing.

You can change layer of an existing bus route by selecting one of its tracks and using Change Layer from the shortcut menu. All tracks in the bus route will be changed to the new layer. Tracks attached to the ends of the bus route will also be changed to the new layer because tracks in a bus route cannot be directly attached to a via.

Individual tracks within a bus route can be edited separately by selecting one of them and using Remove Bus Route from the shortcut menu. All tracks in the bus route will no longer be attached together, and can be edited separately.

You can change the order of the nets in the bus route by selecting one of the tracks and using Define Bus Route Nets from the shortcut menu. The Bus Route Nets dialog (described above) will be displayed, but you will only be able to use it to change the order of the nets. This option is also available whilst editing the bus route path, but if the bus route has tracks attached to either of its ends, it will only be available if Online DRC is turned off.

An alternative and often easier method of changing a bus route path is to remove the track segments in the middle and add a new bus route, starting from the dangling set of tracks at one end and ending on the dangling set of tracks at the other end. Start the new bus route by framing over the dangling ends of the existing bus route. The gaps between the parallel tracks will be kept to match the existing bus route.

Use the Cut Track interactive option to remove track segments from the bus route as it will cut the tracks in a straight line ready to use for adding a new bus route.

This method can also be used to split a bus route to go around an obstacle or to drop the outer tracks and continue adding a bus route with less tracks. Just frame the correct number of route ends that you wish to continue with the next bus route.

There are some Interaction Options to use when adding and editing bus routes. These can help avoid folding the track back on itself and avoid acute corners, and also show the actual on grid path between the middle two tracks that is being edited.

Using double click on the junction at the end of a bus route, or selecting the junction whilst in Add Track mode will allow you to add additional track segments at the end of the existing bus route. If you want to add a single track an the end of a track in the bus route, enter Add Track and click on the connection attached to it. If there is no connection attached, in Add Track press the Ctrl key down whilst clicking on the end of the bus route.

As you can see in the diagrams above, you can highlight bus routes using a different colour.

Related Topics

Using Bus Route | Cut Track | Differential Pairs | Edit Track | Grids | Online DRC | Segment mode | Status bar | Technology | Track Properties