DRC errors using MAGLEF/LEF view with sky130A

[kareefardi]

def-drc.tar.gz Attached are two test cases. Both runs DRC on a DEF file. One sets MAGTYPE to MAGLEF (run.tcl). The other reads the PDK cells LEF files run2.tcl). Both produce DRC errors All nwells must contain metal-connected N+ taps (nwell.4). I am trying to understand if this is expected in abstract views in the standards cells.

[RTimothyEdwards]

Inevitably, abstract views will not have proper connectivity. It is a bit of a difficult problem for things like the standard cells where the nwell is not connected to anything else and so it cannot be replaced with, say, "obswell" (well obstruction layer). Ultimately it may need a completely different solution, such as allowing magic to ignore DRC on specific cells, but I have not gone that direction because the DRC in magic is done flattened, and removing cells tends to create DRC artifacts. Possibly there's a simpler solution that would take the existing method and just figure out how to eliminate errors such as the (nwell.4) error, maybe by ignoring errors that are entirely inside the boundary of an abstract cell.