kicad-developers team mailing list archive

[Oleg Endo <oleg.endo@xxxxxxxxxxx>]

This is funny.  Without being aware of Horizon (at that time),
originally I was hoping to implement something like that in the net
inspector.  But then I had to take shortcuts... 

Cheers,
Oleg

On Wed, 2020-09-23 at 10:58 +0200, Kliment (Future Bits) wrote:
> For length tuning, the nicest interface I've seen is the one in Horizon
> as demonstrated at the 2019 FOSDEM talk
> https://archive.fosdem.org/2019/schedule/event/horizon/ at about 9
> minutes in - it's not a long way between this and the hacked net
> inspector dialog you describe.
> 
> Kliment
> 
> On 23.09.20 10:48, Oleg Endo wrote:
> > This external spreadsheet nonsense was one reason why I converted the
> > net inspector dialog to be non-modal.  And with filtering, grouping and
> > sort-by-length it can be actually a very useful and productive tool. 
> > I've used my own "hacked" version on several designs already. :)
> > 
> > Cheers,
> > Oleg
> > 
> > On Wed, 2020-09-23 at 09:45 +0200, Nick Østergaard wrote:
> > > Hi
> > > 
> > > Slightly related to this discussion and for inspiration:
> > > 
> > > https://twitter.com/azonenberg/status/1282188633118699520
> > > 
> > > Nick
> > > 
> > > On Wed, 23 Sep 2020 at 09:43, Alexander Shuklin <jasuramme@xxxxxxxxx> wrote:
> > > > Hi Kliment,
> > > > I think if these things you explained will be implemented, it will make high speed design very much easier.
> > > > And the problem is much worse if you have a lot of differential pairs. When I see design and the only thing which I can do with differential pairs is to tune length or redraw, I feel stressed.
> > > > Is it right that diffpairs are always treated as just single tracks now? If I want to write a script or piece of code to change diffpair width or gap, what idea should I use?
> > > > I think about finding all coupled lengths of some differential pair and changing the gap on all of coupled lengths and don't touch it if it is uncoupled... Or maybe shift a bit (by gap/2 difference for each side)
> > > > 
> > > > On Tue, 22 Sep 2020 at 22:23, Kliment (Future Bits) <kliment@xxxxxxxx> wrote:
> > > > > Having just routed a board with 56 diffpairs I have an idea about number 4:
> > > > > 
> > > > > I think we should treat diffpairs as single traces when routing and when
> > > > > using the pns functionality to move them around. The trace should have
> > > > > the thickness of 2x dpair trace width + 1x dpair trace gap, and have a
> > > > > clearance of dpair clearance. It should behave as such a trace to the
> > > > > pns and revert back to being a diffpair when shoving/pns manipulation is
> > > > > done. This way dragging, rerouting, and shoving diffpairs works as
> > > > > expected - it maintains the diffpairness of the pair. Length adjustment
> > > > > works just as well on a single trace, and places where the pair splits
> > > > > up or has a skew tune can remain locked while the trace is being
> > > > > manipulated. This requires minimal change to the pns (we just feed it
> > > > > different data) to work, and would dramatically improve the usability of
> > > > > diffpairs because all the lovely stuff we can do to traces now will be
> > > > > available to diffpairs without breakage. We still need the diffpair
> > > > > routing logic for vias and for starting/ending pairs, but we have that now.
> > > > > 
> > > > > On 22.09.20 21:11, Tomasz Wlostowski wrote:
> > > > > > My 5 quick cents:
> > > > > > 
> > > > > > >     1) tool to visualize nets lengths (similar to
> > > > > > >     https://github.com/MitjaNemec/Kicad_action_plugins#length-stats ). I
> > > > > > >     want to make a gui where you can define what nets you want to see
> > > > > > >     altogether. And it should show you length on each layer and summary.
> > > > > > >     And vias as well.
> > > > > > 
> > > > > >       2) Same stuff for length between 2 objects (for example via and pad
> > > > > > >     for T-topology) similar to
> > > > > > >     https://github.com/MitjaNemec/Kicad_action_plugins#pad2pad-track-distance.
> > > > > > New DRC will take care of that (checking length between arbitrary
> > > > > > endpoints as well as reporting constrained length traces/diff pairs).
> > > > > > 
> > > > > > 
> > > > > > >     3) some tool to define and automatically change tracks length on
> > > > > > >     different layers (to match target impedance)
> > > > > > Did you mean per-layer width/gap constraints? abs(Impedance) is not
> > > > > > related (at least not so simply) to trace lengths. We already have
> > > > > > length tuner tool, with the V6 design rule system it will be able to
> > > > > > pick length constraints from board design rules instead of hand-typed
> > > > > > values.
> > > > > > 
> > > > > > >     4) Tool to work with differential pairs. 
> > > > > > We didn't plan implementing such a tool. Beware that even if it happens,
> > > > > > applying more than cosmetic changes to the routing globally will likely
> > > > > > ruin your board so badly you'll spend rest of the day cleaning it up...
> > > > > > 
> > > > > > Tom
> > > > > > 
> > > > > > 
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