The board is going to be 4 layers, with one layer dedicated to ground, another to supply and the top and bottom with signals
The problem is that by the location of components I need to cross the digital signals directed to the LAN with an group of analog signals coming form an DAC, and I don't have any idea of what ground plane put under this cross section, an Analog Ground plane or an Digital Ground plane.
This is a picture of the cross that is bugging me
The red are analog signal (in top) an the blue (in bottom) are the RMII interface and another digital signals.
I've tried to do some research http://www.hottconsultants.com/pdf_files/june2001pcd_mixedsignal.pdf, and http://www.analog.com/library/analogdialogue/archives/43-09/edch%2012%20pc%20issues.pdf but I still can't convince myself of the best strategy to put the in this case.
Any suggestion will be welcome, or if somebody known of another forum where I could get an answer.