Re: [Gnucap-devel] Logic device (U) and switch level simulation

[Willis Shih]

Hi Al,

S device looks like a unidirectional device. Is there any way to
model a bidirectional switch device like tranif1 of Verilog in gnucap?
I'd like to model the pass gate of 6T sram cell, but the S device seems
not suitable for this purpose.

Willis


Al Davis wrote:

> On Friday 12 September 2003 04:36 pm, Willis Shih wrote:
>  
>
> > There is a U: logic device in gnucap for logic mode
> > simulation. How to run logic mode simulation on switch level
> > devices like transmission gate logic? U device seems not
> > suitable for switch level devices.
> >    
>
> You could use a switch (S device).
>
> The down side of this is that it doesn't have the "implicit 
> mixed mode" automatic mode switching.  You may not need this.
>
> The gnucap S device is more efficient than the spice equivalent.
>
> What is really needed is a switch level "level" for the mosfet, 
> and to enable the mode switching there.  Doing this also opens 
> up an interesting new homotopy method, for improving 
> convergence.
>
>  
>
> > BTW, is there any preprocessor to parse hspice netlists and
> > models?
> >    
>
> I keep hoping someone will make a configurable preprocessor to 
> handle the many variants of spice formats.  Gnucap will take 
> some HSpice extensions directly.
>
>
>