kicad-developers team mailing list archive

[<xarx@xxxxxx>]

Sorry, Jean-Pierre, but your answer is too vague for me. I'm just a EE
hobbyist, so I'm surely less experienced than you EE professionals. But at the
level I want to use KiCad, I don't think your  points are valid. See my
comments below.

> 
> Again, we are thinking a good and strong support for simulation in
> Eeschema is a good thing.
> 
> I 100% agree with Wayne said about changes in Eeschema relative to spice
> support.
> Spice support is also not an easy task.

I'm not saying it's easy. User friendly Spice support would mean a lot of work
(considering the current state). But as a first step, you have to be
determined that you want it, which you nor Wayne currently seem to be.

What in particular do you have in mind of what Wayne said?

> Here are a few responses to your proposals (at least here is my opinion):
> 
> * Having "agnostic" component libraries that could be used both for PCB
> creation and simulations is an utopia (excepted for basic cases).
> For instance when you are using diodes like BAV99 (or any diode array)
> or transistors like IRF7606PBF (and any transistor array), and more
> generally speaking any multi-part per package components.

Again, what problem in particular do you mean? I don't see any. Simply, you
would need to have a Spice sub-circuit in order to be able to simulate such a
component.

> * Having the integration between KiCad and Spice standardized at the
> KiCad level (so that new KiCad users can start simulations immediately,
> without a need to prepare their own libraries and post-processing
> scripts) is also (excepted for basic cases) an utopia ( considering the
> words "without a need" ) : Using spice for simulations needs a good
> knowledge of psice:
> Just think about to simulate a transformer, or 2 coupled inductors.

Again, you need to have a prepared Spice sub-circuit for that. If you need
parametrisation, that sub-circuit could be generated dynamically. Where's a
problem?

> * you also need to include simulation files info for complex components
> (obviously op amps)

Yes, of course. No problem.

> * you also need to include many other info (I and V generators, probes ...)

Not exactly. When you run LTSpiceIV on a netlist, you can perform simulations
even without probes.
Concerning the current and voltage sources, in many cases they can be
generated dynamically based on power connectors used in the circuit. They
don't need be a part of the circuit. I'm doing that like this now. In the rest
of cases, there can be presented a dialogue that can help to determine
parameters e.g. of an input signal.

> I certainly forgot many other reasons, but I am not a spice specialist.
> Each time I had a sub schematic to simulate, I used LTspice, which works
> fine, and does very well what it is designed to do.

Yes, you can redraw the simulated part of the schema into LTSpice, but why do
you do that? I assume that's only because you cannot use KiCad for that.

> First of all, you should write a list of all spice info which is needed
> for spice simulation support (at least a minimal list of features)
> Because the schematic files format should be redesigned, this is important

Do you want me to do that, or was that just a rhetoric remark?

> FYI, copying a selection in a schema and paste it elsewhere is an
> especially tricky feature: just think about libraries which can differ
> between 2 schematic projects, and the reference (designator) management,
> especially with multi-part per package components.

The same problem you have e.g. in any programming language where the used
libraries may be missing at the target location. For instance Eclipse IDE for
Java handles this problem in a very elegant way - it just copies the code
including the library imports.

> A schematic editor is not a word processing editor.
> 
> Besides, running spice on a schematic is just a step.
> How do you display the simulation info?

What do you mean by the simulation info? Do you mean the graphs? I use LTSpice
or NgSpice for displaying that.

Best regards,
         Martin.

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