open-source-silicon.dev

To generate extracted spice circuits with magic, is it still required to use "ext2sim" to create the .nodes file?  Some of the settings seem to have changed. But in general, I do:
```extract
ext2sim labels on
ext2sim
extresist simplify off
extresist all
ext2spice extresist on
ext2spice```

I think it depends on the kind of information you'd like included in the spice. If you want to just use it for LVS, then you just need:
```extract
ext2spice lvs
ext2spice```
If you need the resistance information included, then you need the sequence you mentioned above to patch the .ext files as explained here (<http://opencircuitdesign.com/magic/commandref/extresist.html>).

<@U016HSALFAN> my question is that is for magic 8.2 and still references the ext2sim command. It seems weird when I don't actually want a ".sim" file but a ".spice" file.

<@U0175T39732>:  I am painfully aware of this issue.  I do not know who implemented "extresist" (many years ago), but the choice of using the ".sim" format to shuffle data around was a poor one.  The ".sim" format is just being used as a way to get magic to flatten the circuit, dump information about nodes and devices, and then read that information back.  Then that information is folded into the existing SPICE netlist, and rewritten as a new SPICE netlist annotated with the additional resistors.  It's kludgy as all get-out.  My observation is that all the data that extresist uses from the .sim file is already available in the .ext file after "extract all", and in fact the .ext files contain more and better data (such as substrate connections).  My current plan is that some time in the near future I will rip the dependency on the .sim format out and replace it with a routine that reads back the node and device information from the .ext files.  The entire process of generating an R-C netlist would then be, e.g., just "extract all", "extresist tolerance 10", "ext2spice extresist on", "ext2spice".  Probably I would then have an "ext2spice rcx" similar to "ext2spice lvs", that would set up and execute ext2spice with options appropriate for typical full R-C extraction.

Ok. Thanks. I just wanted to confirm. Maybe I can find a student that wants to do this as a project too