Hello,
It is possible to instantiate an instance with (CDF) properties/parameters in a cell in two ways: manually through the graphical layout editor or by using SKILL code from the command line in the CIW. The same can be said about instantiating instances in a cell in schematic.
This is what we see when we do it manually:
- Create a new cell - view (i.e. cell name = testManual, view name = layout)
- Instantiate an instance with properties (i.e. a transistor) with all default values, so do not change any of the properties
- After the instance has been instantiated, select it and then perform the following two commands in the CIW:
- object=car(geGetSelSet())
- length(object~>prop)
- The output of 3.b is a numerical value telling you how many properties are stored for that instance. This number should be equal to the number of properties that can be found in the CDF Editor for that particular instance (at least the same as the number of properties with the storeDefault flag set to TRUE)
This is what we see when we do it using commands in the CIW:
- Create a new cell - view (i.e. cell name = testSkill, view name = layout)
- Perform the following commands in the CIW to instantiate an instance in a cell, use values for libName, cellName, viewName that are valid in your environment:
- cv = geGetWindowCellView() ;;; To get the dbId of the cell view we're editing
- newInstId = dbOpenCellViewByType( libName cellName viewName ) ;;; To get the dbId of the instance we're going to instantiate
- inst = dbCreateParamInst(cv newInstId "inst_0" 0:0 "R0" 1)
- At this point, you should have an instance in the cell - view testSkill - layout
- Select this instance in the layout editor and perform steps 3.a and 3.b of the manual instantiation
And this is where we see the difference: when performing the manual instantiation the length is correct, when doing it through SKILL commands the length is 0 (no properties stored). This puzzles us: what is the difference between manual instatiation and code instantiation? We expected this to have the same output.
In some code we're developing we're relying on the availability of all properties when instantiating an instance. When we encountered this, we thought we had the solution by invoking CCSinvokeInstCdfCallbacks(inst ?useInstCDF t ) (this is code we got for a different problem, but it seemed to work in this case). But this did not solve all the problems. Not all properties will be stored after invoking this command. If the list of properties has for instance 35 entries, after CSSinvoke... we only see approximately 27 entries (just to give an idea). The entries that are missing apear to be randomly chosen: we're missing strings, cyclics, booleans and integers/floats. But they all tent to be towards the bottom of the list of properties.
We have tried many other commands to instantiate an instance but all had the same outcome: none of the properties are stored, or not all after CSSinvoke....
What we would like to know:
- Is this expected behavior, and if so, why?
- What must I do to ensure that when I instantiate an instance all properties are stored?
A little information:
The PDK is developed by ourselves, so if something needs to be done there, that is possible. All CDF properties have the saveDefaults flag set to TRUE, so all strings, booleans, cylics and integers/floats. All properties are needed since a colleague is developing a validation toolkit to validate the PDK we're developing, to ensure nothing breaks when releasing a new version. This validation toolbox automatically instantiates hundreds of instances in many cells to do various checks (check-and-save, simulation, drc, lvs, etcetera) and is fully automated.
Any help here is highly appreciated.
With kind regards,
Sjoerd
