Re: gEDA-user: Is there a *official* JFET symbol in gEDA?

[John Doty <jpd@xxxxxxxxx>]

On Jun 26, 2009, at 11:51 AM, Anthony Shanks wrote:

> I see, I didn't know whats how spice-sdb works, never really used that
> backend, just the spice one.
>
> What do you mean by overloading? Nearly every symbol shipped with
> gschem

Those are just the starting points for a proper set of project symbol  
libraries.

> has a device attribute (caps, resistors, etc.), so it's safe to
> use the device attribute unless people are manually deleting it,

Of course people are changing it to fit their project's flow.

> thus
> freeing up refdes (this is how every other schematic/netlisting flow I
> have ever used works in the professional field). In what instance
> would people be setting the device to a part number?

Oh, for example, when the device= attribute identifies the part for  
the bill of materials. Many library symbols have the part number as  
the device= attribute (bav70lt1-1.sym for example).

> spNet is designed
> for the purpose of spice simulations,

Have you tried the spice-sdb back end to gnetlist? It has its quirks,  
but it's eminently usable. I've designed a 6000 transistor mixed- 
signal chip using it. Stuart is really nice about fixing problems  
with it. At the very least, you should understand the existing tools  
before making something incompatible.

> so if people are using discrete
> analog components and subckts this shouldn't be an issue. If people
> are using spice models of the components they are using this is taken
> care of with the value field.

You should be using the model-name= attribute for that. That's the  
standard. Don't overload value=.

>
> On Fri, Jun 26, 2009 at 6:32 AM, John Doty<jpd@xxxxxxxxx> wrote:
>>
>> On Jun 26, 2009, at 4:02 AM, Anthony Shanks wrote:
>>
>>> The device property has nothing to do with simulations.
>>
>> Depends. spice-sdb uses device as part of the process it goes through
>> to determine what prefix letter, if any, to add to the refdes to
>> comply with SPICE conventions.
>>
>>> IIRC gnetlist
>>> chooses how to netlist a particular symbol according to it's refdes
>>> and uses the value property as the value for netlisting. I don't  
>>> think
>>> the device property is used for anything. I am however making spnet
>>> use the device property for netlisting to decide what the device is
>>> and leaving refdes open for choice.
>>
>> I don't think this is a good idea. You are overloading an attribute
>> that is already used for other purposes. Often, it's a part number.
>>
>> John Doty              Noqsi Aerospace, Ltd.
>> http://www.noqsi.com/
>> jpd@xxxxxxxxx
>>
>>
>>
>>
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>
>
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John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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