Electra
The tabs of the dialog for external auto routers
In Tab "Signals" all unrouted signals appear in a list. Which signal you'dlike to have routed please select by highlighting its signal name in the list. Using the [Ctrl] key you can highlight several signals at the same time. Clicking it again will unhighlight it. With the buttons "Select all", "Deselect all", you'll have them on one strike. If you press "Start", without having highlighted any signal, all signals get routed.
Image: The "Signals" tab in the External autorouter dialog
In section "Signal tracks" you can enter to the line "Minimum Track width:". This value is taken at minimum while routing even if you define it smaller in the schematic signal. But if you define a bigger value in the schematic signal than the one entered here, the bigger one will be taken. The same with the minimum spacing of tracks. At first the distance copper to copper counts. In the project test dialog the aura can be added. Vias also can achieve minimum width values regarding the drill hole. The width of an annular copper ring around the drill hole can be defined. An annular ring exists if a 4mm copper circle is center drilled by a 2mm drill. Around the hole a ring of 1mm width remains. The minimum entries here control the size of the vias.
The tab "Algorithm" allows strategic settings. Memory structures (as far as used in the layout) might be routed first in order not to have too many obstacles later. The same with fan outs at packages having a narrow pinout. Fan outs allow an escape to the opposite layer with a differently preferred routing direction. During disentangeling passes connections are made, during optimization passes the track lengthes are tightened.
Image: Tab "Algorithm" in the External autorouter dialog
Set the path to the electra exe You can tell TARTET 3001! where the electra exe is located. Enter the path to the line: "External Router, program-file" so that TARGET 3001! will start it.
In tab "Route layers" please select a certain routing layer and in the area to the right define how the layer shall be used for which signals. Preferred routing direction means the preferred direction of the tracks on one layer face: horizontally or vertically.
Image: Tab "Route layers" in the External autorouter dialog
Good if for every layer a certain preferred routing direction is defined. Rrouting in all directions upon one layer can be avoided that way. At the same time one can predefine certain layers for certain signals or forbid them for certain signals. A Route prohibition area is defined on a certain layer having exactly this function.