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

[Anthony Shanks <yamazakir2@xxxxxxxxx>]

On Fri, Jun 26, 2009 at 3:43 PM, John Doty<jpd@xxxxxxxxx> wrote:
>
> 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).

Ok, it looks like the bav70lt1-1 is a diode (from datasheet, didnt
know what it was offhand). If you are putting this device in your
schematic you are either simulating it as an ideal or using a subckt
model provided by the vendor. How would you make that distinction in
your schematic? In my mind logically how I designed my netlister to
work, if you use device=DIODE it will netlist as a ideal diode, if you
use device=SUBCKT, it will netlist as a subckt, with value being the
name of the part (in this case, bav70lt1). Only 3 attributes are
required, the flow is logical, and the part name is retained.

>
>> 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.
>

gnetlist regardless of the backend used does not expand subckts
hierarchically and its missing a few other features that industry
netlisters have and I'm trying to bring this to the gEDA community.
I'm trying to make this netlister 100% compatible as a drop in to the
current set of gEDA symbols thus the existence of this thread.

>> 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=

Even gnetlist uses the value= attribute for this. Why would I change
it? For example, if you netlist a schematic that has hierarchy below a
cell it will use the value= attribute for the subckt name.

>
>>
>> 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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