I normally don't autoroute anything, but I'd like to try it on a board I'm working on. Problem is this board is 8 layers and my seat is limited to 6 layers. I'm thinking I can remove the layers where I have the power and gnd planes from the stack up and disable those nets in CM. Then add the layers back in after the routing has been done.
If this will work, how do I "lock" any existing traces I have routed to prevent the autorouter from moving them?
Tom I had not seen any tutorial's on Specctra, Perhaps I should make a YouTube video that goes over the basics :)
I have used it for a long time and it can take awhile to get used to it but it is fairly easy. When you are in Allegro you can invoke specctra from the Allegro Tool-Bar. "Route > PCB Router > Route Editor" This will start Specctra and allow you to manualy route a board.
Traces that have been routed in Allegro may appear with a white-line through them in Specctra. This means these routes are protected so you would have to un-protect the routes in specctra before you could re-route them or edit them.
The keys so to speak in spectra for certain actions are done by selections so in the case of protected traces we could "select all wires first then un-protect all of those selected nets and finally un-select all routing objects so they are no longer selected.
Sounds a bit difficult in e-mail, if you were to see it done you would think it is fairly simple and kind of makes sense.
The other thing about specctra is pretty much all PCB editors can export their PCB in the specctra format for routing of a board. This means that you could support routing boards from a wide variety of PCB tools with your cadence tools and thats kind of cool.
Here is a blow by blow to do list to get you going.
Configure your Grids First " View Display Grids" There are grids for wires,vias,placement. leave the box that says factor set to -1
Configure Your Layer Colors "View Layers" Color palette at the bottom of the layer screen. When your colors are set go back to the layer screen. You will notice the actual layers in your design. Click on the color box beside a layer name to turn the layer on and off. Also notice there is a pop down box to choose routing bias on a layer as you change things you will notice the command window will tell you what you did.
Next select View Guides All to turn on the rats nest if it is not on
Last click the edit route icon to route manually. Click on some pins with nets to route those suckers in. Use RMB for additional options.
Thats about it.
When you did your training course did they not cover Specctra ? in the class.