Dear Forum:
I am in need of some guidance... I think I have figured out that what I am doing is not possible but I am hoping the forum can help provide some alternatives to accomplish the goal and some explanations of why it isn't possible.
I will need to give some background first:
I am running top level simulation verification using cadence ams through the analog design environment gui. My schematic with config view has two instances, STIM for stimulus and DUT for device under test. Inside of the DUT (top level chip of course) is a bias block with a feedback connection. The bias block is represented by a verilogA model that is already known to match the real schematic.
The problem that I have is trying to figure out how to probe the input and output pin voltages of the bias block to verify the feedback connection is in the top level schematic as required.
i.e. compareValues(V(testbench.dut.bias.out), V(testbench.dut.bias.in), tolerance...); //note this is pseudo-code
Recall my stimulus is an ams block and the model is verilogA. When I try to access the potential (from the ams stimulus) of the pins (verilogA block), I get an error about attempting to modify defparam and that it is not allowed...
I've looked into the LRMs for ams and verilogA. From the ams LRM I found verbage that I believe says you can't do what I am trying to do.
First question: Why not? What is the technical limitation?
Second question: Why does the simulator think I'm trying to modify defparams?
Third question: What are some other ideas for verifying that the feedback wire is in the top level schematic?
Fourth question/comment: It seems that I will need some clever way to use wreals or $numtobits $bitstonum, is that correct? Based on my reading of the LRMs this seems to be the only practical way to do what I am trying to do...
Thanks in advance for helping me understand this better. I am new to ams and obviously have more to learn!
![Smiley Smiley](https://designers-guide.org/forum/Templates/Forum/default/smiley.gif)
-Dan
FYI: I am using:
DFII: 5.10.41.500.6.132
NCVLOG: 08.20-s009
MMSIM: 7.0.1.136.isr12