Routing using the Autorouter

The Autorouter contains the following elements:

• Routing Consultant: the routing Consultant analyzes your design area and identifies areas that will prevent the successful routing of the design. It then provides advice on how to overcome these problems.
• Routing Strategy: the Routing Strategy dialog allows you to manage and review all stages of the routing for the design area. It also allows you to select appropriate tools, and define the order in which to run them. This enables you to specify routing targets for the routing process.

The procedures shown below describe how to perform automatic routing within a routing area using the Autorouter command. This command is only available in 2D View mode.

Starting the Autorouter

The following procedure describes how to specify an area to be routed, and how to start the Autorouter.

1. Create a routing area. See: Creating a Routing Area.

2. Select the routing area created in Step 1, or an existing area that you need to route.
3. On the ribbon, click Net / Route > Autorouter > Autorouter. The Routing Strategy dialog is displayed.
4. Perform routing using the Routing Strategy dialog.

Target objects

A routing area is the only valid target object.

Importing Routing

You can import Autorouter routing as follows.

1. Select the area in which routing has been completed using the Autorouter.
2. On the ribbon, click Net / Route > Autorouter  > > Accept Routing.
3. If there is a track pattern or via pattern included in the selected routing area, then these are removed before importing the Autorouter routing.
4. Targets for importing are track patterns and via patterns.

Target objects

A routing area is the only valid target object.

Assist menu

The following items can be selected by right-clicking the mouse:

Apply

Exit

Using the Autorouter

The following tips are provided for using the Autorouter effectively.

Net layer

You can specify on which layers a net will be routed, on a per-net basis. You can specify a single layer, multiple layers, net level, or net class level.

1. Customize the Constraint Browser, and display the attribute for net layer. See: Customize Table Configuration Dialog.

2. After customization, click the button, displayed in the Net Layer column. The Autorouter will route on the specified layers only. Even if the outer layer on which pins exist is not specified, this layer will be used to connect to the pins.

 

 

Pin exit direction

• During autorouting, pin exit directions are considered for all pins.
• When registering a footprint, you can specify a pin exit direction for each pin.
• If the direction is not specified during footprint registration, then it is automatically set as shown below.

Item	Description
The shape of the minimum rectangle encircling all pin figures is square.	Eight directions (to each side and to each corner, from the center of a pin).
The shape of the minimum rectangle encircling all pin figures is rectangle (component has four or fewer pins).	Four directions (to each side, from the center of a pin).
The shape of the minimum rectangle encircling all pin figures is rectangle (component has five or more pins).	Two directions (to short sides, from the center of a pin).

 

To ignore the pin exit direction in routing, select the Ignore Exit Directions check box in the Autorouting Costs tab of the Routing Setup dialog.

 

 

Anti-track layer

In the Autorouter, you can set a flag called the anti-track layer to layers. In autorouting, routing is not usually performed on the layer specified as anti-track layer. Routing is only performed on anti-track layers when it cannot be completed on the specified layers. An anti-track layer can be specified in the Layers dialog. See: Setting Layers

Semi-fixed

In the Autorouter, you can set a flag called the semi-fixed to track patterns. During autorouting, tracks specified as semi-fixed are protected from editing, and are not pushed aside. A semi-fixed track is moved only when it obstructs the routing of other tracks. To semi-fix a track pattern, specify it in the Operation column, in the Routing Strategy dialog.

Bias

During autorouting, the bias specified in the design rule is considered. You can also change the bias setting in the Layers dialog.

Performance in Autorouting

The following tips improve the time to complete autorouting.

Display lock

Updating the display on the canvas during autorouting causes the drawing time and routing time to increase. You can reduce the routing time by stopping the update of the display, as follows:

• Set Force Lock Display when executing task to ON in the Strategy Options dialog. See: Configuring Strategy Options.

Fixed patterns

Patterns that are fixed may increase the routing rate and routing time in autorouting. Routing completion can be increased, and routing time reduced by limiting the number of fixed patterns.

Routing area

Routing time can be reduced by making the shape of the routing area as simple as possible.

Pin exit direction

You can increase routing completion, and reduce routing time by increasing the number of pin exit directions.

 

 

Fan-out

You can increase routing completion, and reduce routing time by executing fan-out, in advance, for single layer pins such as surface mount components.