Hello,
The following question does not have a clear answer for me after reading some of the Cadence documentation on modgen. I have been using modgen only recently and find it very useful, but wondered about the following case. I believe you have to be using IC 6.1.7 to even see modgen:
Q: I have created a modgen in Schematic-XL and placed the devices how I want to in the Modgen layout editor through Module Generator. After saving and closing all of this, I later realize I want to change an NFET from m=2 to m=4. What is the best way to make this change?
Main problem I see is not having a simple way in Schematic-XL to update in the constraint manager the specific device I changed, so that the two additional devices (now m=4) show up within the modgen group. For example, if constraint manager showed Modgen(12) because I had 12 devices grouped, it should become Modgen(14) after I increase the m=2 to m=4. The "update constraints from layout/schematic" options do not seem to do anything.
What I've had to do is delete the original m=2 devices from the modgen constraint group, then add the m=4 devices back into the modgen group. But then sometimes when I open Modgen Layout Editor it resets the positions of all the devices I had placed before the change. I've tried making the schematic change only after I've had the Modgen Layout Editor open as well, but it doesn't work as smoothly either. It also isn't clear to me in which cases I use the "update all schematic constraints from layout" or "update all layout constraints from schematic" commands.
Does anyone have any suggestions on how to best modify an instance's m-factor after having already performed the layout placements in a modgen? And so placement doesn't reset?
Thanks,
af