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Hello, please could anyone clarify which versions of Xschem + Ngspice we should be using?  We need to simulate all of the XSchem example circuits, those we have just taped out on Sky130 with the latest PDK (which simulate with `Ngspice 38`), and the Re-Ram circuits. The latest version of Ngspice [41] no longer simulates the example circuits in Xschem V3.1.0 or any of our old designs it seems.

<@U03SX0UNJRZ> I always use the latest version of ngspice. As for xschem, you might need to check the output netlist and why it’s not simulating 

<@U01EK2VDMDG> thanks for your message :slightly_smiling_face: so you have not experienced any problems with simulating the Xschem example circuits in the latest version of Ngspice?

We fix any issues we face. Share the netlist and we might be able to help.

Newest xschem versions should read old files with no problem. If you have problems on specific schematics let me know. It is my top priority NOT to break older designs, the file format is never going to change in a non backward compatible way.

Hi <@U01819B63HP>, we don't think that Xschem is the problem - it seems that the latest `Ngspice 41` is having trouble parsing the output from `Xschem V3.1.0` and not simulating correctly any more. `Ngspice 38` and `Xschem V3.1.0` work well together, however, we need to upgrade Ngspice in order to simulate ReRam. So just wondering if there's a combination of versions which would work together to cover all bases?

<@U01EK2VDMDG> will share a netlist shortly, just trying to find a clear test case! Thank you

Just realised our Xschem is a bit out of date, so will try updating to the latest version too and try again.

If you see problems with old and new Ngspice and/or with new and old Xschem  may be you should try one change (xschem new vs old and ngspice new vs old) at a time. If you have a netlist that ngspice refuses to process I can give it a look.

Thank you. I've had a look and it seems that making everything compatible will be quite a lot of work (we've made some changes to our local Xschem which aren't easily translatable to the latest version). As everything is bound to be updated again before next summer's planned tapeout,  the easiest solution for now is to use the latest Xschem/NG spice for Reram work plus the older versions for our previous simulations. :slightly_smiling_face: