Inheritance in the Pcell Designer

Hi Tobias,

I don't believe this is possible currently. I'll check, but perhaps you could outline what exactly you want to inherit from the base cell into multiple different view types? Just trying to understand what common information (methods etc) you might share across different view types.

Regards,

Andrew.

Hi Andrew,

My main use case would be sharing a common data structure or method for instance creation inside my layout and schematic Pcell, to ensure consistency.

Additionally, it makes things easier if I have to change some parameter of instances inside my Pcell.

I would only have to change one "file" rather than keeping two views consistent manually.

Best regards

Tobias

Hi Tobias,

There's a way of doing this, as it turns out. Normally when you specify where you inherit from on the Edit Device Type (Edit Class) form, you specify just the cell name. However, you can also specify the class name which would allow you to do exactly what you're wanting.

So find out the class name from the parent pcell by using File->Export to File and saving the SKILL++ code. At the top of this file you'll see something like:

(defclass pcdUser_NmosDemo24_topclass (pcdxPCell)
  ((libName @initform "NmosDemo24")
    (cellName @initform "topclass")
    (viewName @initform "layout")
    (cellViewType @initform "maskLayout")
    (_interactive @initform nil)))

The class name I've highlighted in red above. It will be different depending on the view type of the top class.

Then in the pcell you're creating which inherits from this (in my case a schematic view where the top was a layout), enter that class name instead of the cell name:

Regards,

Andrew

Hi Andrew,

I already tried it like this. And worked with this solution in the beginning.

The problem with this solution is that the explicit class name will not be changed in the Pcell deploy step resulting in a not working deployed library.

In your example, if I want to deploy NmosDemo24  into another library lets say Nmos24.

Best regards

Tobias

Hi Tobias,

This is not the ultimate solution - it's a workaround for now until we make this cleaner, and I recognise that it has limitations as you say.

Andrew.

Hi Tobias,

I filed a change request, CCR 2100834 to provide a way to specify both the cell and view you're inheriting from.

Andrew.

Hi Andrew,

Thank you a lot.