Hi,
I am using 4 layers for a mixed signal pcb design. Top and buttom layers are for trace routing, and inner layer 1 is for analog ground, inner layer 2 is for analog VDD.
So, after I placed power plane, and ran the auto routing, there are still a lot of ratsnests unconnected by traces, and I cannot use Top layer and buttom layer to do the manual routing, because that will result same kind of traces cross each other.
Then, I tried to connect these unconnected ratsnest with traces on innner layer 1, I call these singal traces, and I connect pins of chips with top layer traces, and I tried to make the connect of these two traces by using via from top layer to inner layer 1, but apprently ultiboard doesn't allow me to do that. And the error reminder is "Design rules do not allow the selected lamination. Change the selected layers, otherwise the current selection will create a via from Copper Top to Copper Bottom"
My question is how do I connect these ratsnests.
I attached my layout file.
Appreciate your help!
