@Mitch Bailey : Thanks for all the feedback. I have of course gone and made changes by magic 8.3.274 and open_pdks 1.0.289 for more correct handling of substrate, deep nwell, and isolated substrate. I hope by using those versions the number of steps here can be reduced somewhat. The logic analyzer inputs are supposed to be allowed to be open under the condition that any C program driver leaves the inputs in the disabled state. Does that match your understanding of your CVC results? I will want to get the changes you made to the extraction rules and the I/O cell layouts merged into open_pdks. Changes needed to caravel should be posted as github issues in the caravel repository.