Cadence OrCAD PCB Designer

Figure 16. Settings in the Layers box for single-sided routing on the bottom layer and
double-sided routing on both layers.
See the suggestions below if the autorouter is unable to route your board.
5. It is a good idea to use two more commands to improve the layout for assembly. First
choose Autoroute > Post Route > Spread Wires. . . and accept the defaults. This spreads
the tracks out a bit and keeps them further away from the solder pads.
6. You’ll have noticed that the autorouted board has 90° bends in the tracks, which I told you
to avoid when you routed the board by hand. We’ll now sort this out. Run Autoroute >
Post Route > [Un]Miter Corners. . . and accept the defaults. The corners will be rounded
off and tracks run diagonally where possible.
7. To see the details of the finished layout, choose Report > Route Status. This will show
a lot more than you want to know! Look near the bottom to find the Routed length and
Unconnected length (which should be zero). Record these figures in your notebook.
8. Choose File > Quit. . . and agree to Save and Quit. This writes a session file that describes
the routed tracks.
9. Return to PCB Editor and choose File > Import > Router. . . . Locate the Session File
whose name matches your board and click Run. You should see a message Translation
Completed. Close the box.
10. The window now shows your design with tracks instead of the ratsnest. Save it under a
different name to preserve the unrouted board for later.
Hint for demonstrators.
My layout is shown in figure 17. ❦
Help! – My board won’t route
Here are some suggestions for helping the autorouter.
1. If the routing has almost worked (only one or two unrouted segments), try changing the
hints given to the router. For the one-sided board there is only the suggested direction of
tracks in figure 16. It is best to unroute the board and begin afresh. Choose Edit > Delete
Wires > All Wires from the menu bar of SPECCTRA or reload the previous version of
your board in PCB Editor.
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