Hello everyone, I ran into LVS errors when running

make lvs

on the

gcd

design using

sky130hd

platform. Steps to replicate: 1- Install ORFS using docker. 2- Uncomment

DESIGN_CONFIG=./designs/sky130hd/gcd/config.mk

in /flow/Makefile 3- Run

make

4- Run

make lvs

Errors:

ERROR: In /OpenROAD-flow-scripts/flow/platforms/sky130hd/lvs/sky130hd.lylvs: Pin count mismatch between circuit definition and circuit call: 6 expected, got 7 in /OpenROAD-flow-scripts/flow/objects/sky130hd/gcd/base/6_final_concat.cdl, line 11755 in Netlist::read
ERROR: Pin count mismatch between circuit definition and circuit call: 6 expected, got 7 in /OpenROAD-flow-scripts/flow/objects/sky130hd/gcd/base/6_final_concat.cdl, line 11755 in Netlist::read in Executable::execute

This issue seems old but still not solved, right? https://github.com/The-OpenROAD-Project/OpenROAD/issues/1146 Is there a workaround to do LVS? I have tried deleting stuff causing the errors from the .cdl file

flow/objects/sky130hd/gcd/base/6_final_concat.cdl

and I'm left with an LVS error: netlist mismatch. lvs-issue-with-gcd.png

This looks like OpenROAD-Flow-Scripts with sky130 gcd + KLayout LVS. If so, I'm not sure that KLayout LVS was actually ever configured properly for this process. It remains an open item to do so.

Yup, that's the correct process. Do I just take the output GDS for granted or is there a way to do LVS?

I looked at it once upon a time but didn't have time to complete it. I think that it requires some tweaking of the rule deck to get it to extract correctly. You might try lvs on a standard cell (e.g. a NAND gate) to see if it matches and try to debug from there.

Aha, thank you. Is ORFS (platform bring-up) the correct guide for such thing?

I'm not sure there's any guide specifically for LVS :/ I think you might just need to consult the KLayout docs and do a bit of trial and error. For what it's worth, I think OpenLane uses Magic for LVS and they have it working.

Ramy, there is a LVS flow that uses gds and verilog/spice netlists. You can find it here along with some other checks. Let me know if you encounter problems.

thanks a lot I'll check it out.