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Re: parameter usage in simulatoin
From: |
Felix Salfelder |
Subject: |
Re: parameter usage in simulatoin |
Date: |
Sun, 19 Apr 2020 16:45:34 +0200 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
On Sun, Apr 19, 2020 at 04:16:17PM +0200, patrick wrote:
> I am trying to vary W/L parameters of a MOS transistor.
Hi Patrick.
Could you share the model or instanciation of that transistor?
> With this syntax:
>
> .param L1=180e-9
> .param W1=300e-9
with this, you define parameters in the top level scope. they are not
necessarily used for all parameters with that name, not even as a
default.
I suspect that you use subckt parameters, and that they are not resolved
as you were expecting. consider for example this netlist.
param w=2
module m(1,2);
resistor #(.r(w*5)) r(1,2);
endmodule
m m1(0, 1); // !!
Here, you get "parameter w*5 not specified, using default". to pass w
into the subcircuit, instanciate m1 like
m #(.w(w)) m1(0, 1);
and w*5 in m will be five times the global w.
> What is wrong? How can I get some more info on the error.
Indeed, the error message could be improved, maybe print the label of
the instance with the unspecified variable. I don't know how easy that
is. If your error is due to the pattern above, it should still be
simple to find.
cheers
felix