This section includes information that can be useful when working with Autorouter.

General

The layer costs (cfLayer) should increase from the outer to the inner layers or be the same for all layers. Avoid using values in the inner layers that are lower than the outer layers. This could greatly increase required routing memory.

Single-sided boards

In the simplest case, only layer 16, Bottom, is active. No preferred direction is defined. Select a suitable grid and run Autorouter.

Autorouter may use the Top layer as well. The tracks laid there will be realized as wire bridges on the board. In layer 41, RestrictTop, you can define restricted areas around the components and in regions where wire bridges are not allowed.

SMD boards With supply layers

Try routing supply signals first. In general, a short track is recommended between an SMD component and a via that connects to the inner layer.

Before changing parameters, click Save As in the Autorouter to save the current (default) values in an Autorouter control file (CTL file).

Switch off the bus router and all the optimization passes in Autorouter setup. Only the routing remains active. Alter the following cost factors:

cfVia = 0	Vias are welcome
mnVia = 1	Max. one via per connection
cfBase.1/16 = 30..99	Fewer tracks in Top/Bottom
mnSegments = 2..8	Short tracks

open Autorouter, and use the Select button to choose signals to be routed. After the routing pass, you can optimize results manually if you want.

The rest of the connections are routed after this. Click Load to load the previous stored control parameters, and adjust the values as needed.

What can be done if not all signals are routed

If this happens, check your settings:

• Has a sufficiently fine routing grid been selected?
• Are track widths appropriate?
• Can the vias have smaller diameters?
• Have optimal minimum clearances been chosen?

If it is unreasonable to optimize these values any further, try increasing the ripup level.