kicad-developers team mailing list archive

[Jon Evans <jon@xxxxxxxxxxxxx>]

Neat idea, Russell!

In theory, this is possible.  In practice, there are many challenges to
overcome.

The internal representation of the schematic does not resemble the netlist
that is given to PcbNew.
So, a PcbNew netlist (whether generated by SKIDL or anything else) would
have to be "imported" to
the schematic in order to create a "Subsheet from Netlist" as you describe.
This import process would need to parse the netlist and generate the
internal connectivity state
to allow the schematic connectivity code to work with that subsheet the
same way it works with
regular graphical subsheets.

That part is technically possible, but the surrounding code to make this a
nice experience would
also be a significant task.  How would you edit or update the underlying
SKIDL code generating the
subsheet?  How would you display ERC errors that involve both a graphical
schematic and a subsheet
created from a SKIDL netlist?  Would you be able to make changes to the
components on the subsheet
generated from a SKIDL netlist (for example, to edit properties) using the
Edit Symbol Fields
dialog and other things that interact with objects across the whole
schematic hierarchy? If so,
would you be able to back those changes out to valid SKIDL code?

I don't mean to discourage you or others from pursuing things like this, I
just want to caution
that there would be many, many details to talk through and figure out
before a feature of this
complexity could be added to KiCad.

A route that may be easier to implement, and less intrusive, would be to
wait for the coming
Eeschema file format update and Python API, and add support for generating
schematic sheets to
SKIDL itself.  Of course, the complexity there would lie in the algorithm
for laying out the
items described in SKIDL in a graphical fashion.  But, it doesn't have to
be pretty as long as
it is electrically consistent.  You could then include the generated sheet
as a subsheet in the
normal fashion, and update it using Python (since SKIDL is implemented as a
Python library, it may
be possible to have fairly tight integration between SKIDL and KiCad once
the Python API is more
stable and it is possible to interact with the schematic using Python).

Best,
Jon

On Thu, May 2, 2019 at 9:16 PM Russell Oliver <roliver8143@xxxxxxxxx> wrote:

> Hi All,
>
> First off congratulations to everyone involved with KiCon for making
> it a success and the great progress that is happening with Kicad at
> the moment.
>
> I've been following Dave Vandenbout's work on SKIDL [1] a while but
> his talk [2] at the conference on SKIDL really showed the power that
> programmatic circuit design could bring to electronic design
> especially with a simulation/optimization loop.
>
> To that end I wondered weather it would be possible to include the
> netlist output from a SKIDL script into a traditional schematic,
> allowing for the best use of both worlds?
>
> Given that we currently have subsheets that can be reused multiple
> times, could it be possible through the inclusion of a netlist reader
> into Eeschema to read either a netlist file directly or the result of
> executing a SKIDL script and incorporate that back into the larger
> netlist?
>
> I can imagine a type of hierarchical sheet where the user can specify
> the nets to be shown as sheet pins, which would be connected to the
> matching nets from the netlist file.
>
> My question to those with more knowledge of the current netlist
> generation algorithm is how possible this would be?
>
> [1] https://github.com/xesscorp/skidl
> [2] https://www.youtube.com/watch?v=WErQYI2A36M
>
> Regards
> Russell Oliver
>
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