RE: gEDA-user: Power nets in hierarchy

["EATON,JOHN (HP-Vancouver,ex1)" <john.eaton@hp.com>]

I think we are runing into the same issues that plague EDIF
in that there are multiple ways to describe things and getting
everyone to do it the same way is impossible.

Their solution was config files. Along with a netlist you provided
a configuration that specified whether power was provided by a 
net or by connection to a component like a tie_high or tie_low.
You could specify ports as components like the PCB world likes
or as ports like the verilog world likes. You could change from
VCC to VDD or 3.3. as you needed.

Flexibility is the key.

I will probably try an learn guile since it actually seems somewhat
usefull but my main tool builder right now is perl.


John Eaton













-----Original Message-----
From: owner-geda-user@seul.org [mailto:owner-geda-user@seul.org]On
Behalf Of sdb@cloud9.net
Sent: Wednesday, October 22, 2003 9:45 AM
To: geda-user@seul.org
Subject: Re: gEDA-user: Power nets in hierarchy


Why not just define an attribute "GLOBAL" which you could attach to a
net?  A global net would then have two attributes: NETNAME and GLOBAL,
for example:

NETNAME=VCC
GLOBAL=1

Then the netlister would know directly what type of net it was
handling, instead of having to figure it out from the attached
schematic symbol.  In any event, I often just use named nets for power
instead of attaching a power symbol.  Finally, there are other common
nets which aren't power nets but are also globals, such as RESET.
Nets like RESET don't always have an accepted device symbol.

Stuart



> 
> Hi.
> 
> I'd like to have a device type like 'power' for power bus symbols like 
> vdd and vss.  Rather than trying to overwrite the name of the net 
> connected to these symbol's pins, I'd like to leave them alone until 
> after flattening.  Then, I can have a simple pass that changes the name 
> of power nets to that of the power symbol.  I would merge multiple 
> instances of such nets at this time.
> 
> This is different functionality that that given with the 
> net=<netname>:<pinlabel> attribute.  That attribute assigns pins on 
> footprints to signals, even when they are not available on the symbol. 
>  Power devices would globally override nets after flattening, but would 
> have no effect until then.
> 
> What do you think?
> 
> Bill
> 
>