Eagle multilayer board autorouting madness

[simanowitz]

eagle multilayer

Ok, this should be easy, but for some reason it's making me nuts. I am attempting to autoroute a 4-layer board but Eagle insists on only doing the top and bottom. Here's what's happened so far:

I just upgraded from the free version to Pro (never could do multi before today)
From the DRC > Layers tab, set the Setup field to (1*2+3*16)
From the Auto... > General Route 2 and 3 to "|"
I even tried setting Auto... > Busses Route2 and 3 to '0', but that didn't help either.

When I hit Auto... > OK, only the top and bottom route. What stupid thing am I doing? I'm not making a ground or power plane, just a simple TTL board.

TIA,
David

 

[CMOS]

eagle layer setup

It has something to do with DRC. Try loading the default drc file and see if it works!

 

[simanowitz]

4 layer boards in eagle

It has something to do with DRC. Try loading the default drc file and see if it works!

Nope, no luck. The default drc just reloads the 2-layer setup.

 

[CMOS]

eagle multilayer boards

I meant reload default drc file and then again set-up your layers. Dont make any other changes and then retry.

 

[simanowitz]

eagle default drc

OK, I figured it out. If you're going to do multilayer with Pro, you have to do everything that I listed before PLUS set the Routing Grid size to something besides the massive 50 mil. I chose 10 mil and it worked like a champ. Hope this helps someone.

Added after 1 minutes:

Sorry, that's the Routing Grid under Tools > Auto... > General > Routing Grid (upper left side of tab).