Re: gEDA-user: not quite hierarchical netlist

[John Doty <jpd@xxxxxxxxxxxxx>]

On May 19, 2006, at 12:55 PM, al davis wrote:

> On Friday 19 May 2006 13:21, Wolfgang Buesser wrote:
> > Hi everybody,
> >
> > probaly this is a stupid question, but I am having
> > difficulties generating a hierachical spice netlist: I have
> > tried to follow the instructions in the manual and ended up
> > with the following netlist:
> >
> > *******************************
> > * Begin .SUBCKT model         *
> > * spice-sdb ver 12.27.2005    *
> > *******************************
> > .SUBCKT Amp
> > *==============  Begin SPICE netlist of main design
> > ============ MX1/M1 X1/N1 NN X1/GND X1/GND NMOS  l=1.2 w=2.2
> > V1 NIN 0 VIN
> > X1/C1 NOUT X1/N1 Ccomp
>
> This is incorrect.
> Spice (and all Spice format simulators) uses the first letter to
> determine the type.  Since the first letter is "X" that makes
> it a subcircuit call.  A capacitor must start with C.

The problem is that gnetlist was apparently not originally designed  
for SPICE. The hierarchical names it generates are *backwards*: they  
start from the top level and work down, but SPICE needs the name to  
start with the character for the component, not its enclosing circuit.

Again, the solution is to compose separate flat subcircuits, and let  
SPICE put them together hierarchically. And that's just what  
following the instructions in Stuart's excellent tutorial will have  
you doing.

John Doty              Noqsi Aerospace, Ltd.
jpd@xxxxxxxxxxxxx