Re: parameter usage in simulatoin

2020-04-19 Thread Felix Salfelder
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



parameter usage in simulatoin

2020-04-19 Thread patrick
Hello,

I am trying to vary W/L parameters of a MOS transistor.

With this syntax:

.param   L1=180e-9
.param  W1=300e-9

I get:

# simple sweep
parameter L1 not specified, using default
parameter W1 not specified, using default
parameter L1 not specified, using default
parameter W1 not specified, using default
parameter L1 not specified, using default
...


What is wrong? How can I get some more info on the error.

Thanks!
Patrick