I've been meaning to type up something like this for a while.
I've often had the problem, on my complex designs, in routing everything manually and when I think I'm done, ratsnest says I have some unrouted airwires. I could take the easy way and run the autorouter but I'd like to know exactly what I missed so I know what the autorouter would be doing.
Cadsoft themselves provide a useful ULP to do this for you. It’s called Zoom-Unrouted, but does not come installed be default. This is all nice and good, but who wants to repeatedly click on the ULP button, hunt through your directly and select it?
ftp://ftp.cadsoft.de/eagle/userfiles/ulp/zoom-unrouted.ulpHere’s what I've done to bring it all together. You can add it to your toolbar in Eagle! The toolbar that contains the “Design Link” link can be found in your SCR folder in your main eagle directory and is named “eagle.scr”. The script file is broken down into six sections: General, BRD (layout), SCH (schematic), LBR (library), DEV (device), SYM (symbol), and PAC (package). Since we’re looking at adding this ULP to the layout editor, we’ll be adding an entry to BRD’s MENU section. Below is the default code found here.
MENU '[designlink22.png] Search and order : Run designlink-order.ulp -general;'\
'[pcb-service.png] PCB Service : Run pcb-service.ulp;';
Notice the format. Each item is encapsulated in a single quote, the icon is in brackets, followed by the hover text, then comes a colon to sepearate this from the command. Finally you have your run command to execute the ULP that you want. Once you add your entry, it’ll look like the one below.
MENU '[designlink22.png] Search and order : Run designlink-order.ulp -general;'\
'[pcb-service.png] PCB Service : Run pcb-service.ulp;'\
'[unrouted.png] Search for airwires : Run zoom-unrouted.ulp -general;';
I made a simple image for mine showing two top coppers pads with an airwire connecting them. The image you choose needs to be located in the “bin” folder in your main eagle directory. Feel free to download mine in the link below.