Often stupid partitioning of GND in digital and analog can generate muchtrouble, so one single low impedance ground plane can be a simple and not too bad solution.
Yep. But a single plane *may* lead to stray currents flowing near sensitive analog stuff, like ADC and DAC. I don't want to degrade the performance of these parts. In fact, my analog gnd plane is sectioned as well, in order to isolate the high-current section from the low signal portion.
Now that it's not 2 AM, and maybe I'm thinking a little more clearly, the ADC and DAC can be contained in one area, where the digital and analog gnd plane connects. Don't know why I didn't think of that before - that takes care of most of the high speed digital signals that transition between the two domains. That leaves some others, like I2C and pseudo-static
control lines, which I am at a loss on the best routing methodology.
Good luck with your design. The addage "follow the currents" works pretty well in figuring out if you will have trouble. Sort of like pretending your the electron, and see where you go.
gene _______________________________________________ geda-user mailing list geda-user@xxxxxxxxxxxxxx http://www.seul.org/cgi-bin/mailman/listinfo/geda-user