Pcell Creation in Virtuoso 18.1

You've not really given a lot to go on here.

First of all, are you really talking about a PCell? A PCell is a special kind of layout, symbol or schematic where the contents of the view are generated based on a set of parameters passed to some code (generally SKILL in Virtuoso) which usually alters the shapes and connectivity based on those parameters. It is not just where you have parameterised the values of components using pPar() for example. I wanted to say that because often I see the wrong terminology used here which causes confusion.

Conventionally, PCells are built using either SKILL code directly (using, say, pcDefinePCell() to define the PCell, formal parameters, and code to execute) or using a tool to build the code such as PCell Designer, PAS (PDK Automation System), or the old Graphical PCell Editor. Have you done this part?

CDF sits alongside PCells - it describes the component, the parameter types, and potentially some callbacks to allow parameters to be derived from others (not something I'm a big fan of, but can be useful if done carefully - see my article The Dangers of CDF Callbacks). It also describes how primitive components are netlisted. You don't have to have CDF for a PCell - but commonly you would.

Anyway, having done that, you don't have to do anything special to create subMasters. You simply instantiate the PCell master (known as the "superMaster") and based on the values of the PCell parameters passed to that instance, it will actually build the variant (the "subMaster") if it hadn't built that variant already, and instantiate that subMaster instead. If you then change the parameters on the instance, it will re-bind to a different subMaster (building that subMaster from the PCell code if it hasn't been evaluated already). The system itself takes care of this.

Hopefully that's enough of a high level overview to cover your question. If it doesn't, you'll need to provide some more details so we don't have to guess!

Andrew.

You've not really given a lot to go on here.

First of all, are you really talking about a PCell? A PCell is a special kind of layout, symbol or schematic where the contents of the view are generated based on a set of parameters passed to some code (generally SKILL in Virtuoso) which usually alters the shapes and connectivity based on those parameters. It is not just where you have parameterised the values of components using pPar() for example. I wanted to say that because often I see the wrong terminology used here which causes confusion.

Conventionally, PCells are built using either SKILL code directly (using, say, pcDefinePCell() to define the PCell, formal parameters, and code to execute) or using a tool to build the code such as PCell Designer, PAS (PDK Automation System), or the old Graphical PCell Editor. Have you done this part?

CDF sits alongside PCells - it describes the component, the parameter types, and potentially some callbacks to allow parameters to be derived from others (not something I'm a big fan of, but can be useful if done carefully - see my article The Dangers of CDF Callbacks). It also describes how primitive components are netlisted. You don't have to have CDF for a PCell - but commonly you would.

Anyway, having done that, you don't have to do anything special to create subMasters. You simply instantiate the PCell master (known as the "superMaster") and based on the values of the PCell parameters passed to that instance, it will actually build the variant (the "subMaster") if it hadn't built that variant already, and instantiate that subMaster instead. If you then change the parameters on the instance, it will re-bind to a different subMaster (building that subMaster from the PCell code if it hasn't been evaluated already). The system itself takes care of this.

Hopefully that's enough of a high level overview to cover your question. If it doesn't, you'll need to provide some more details so we don't have to guess!

Andrew.