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 <jasura...@gmail.com> 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) <klim...@0xfb.com> > 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 >> > >> > >> > _______________________________________________ >> > Mailing list: https://launchpad.net/~kicad-developers >> > Post to : kicad-developers@lists.launchpad.net >> > Unsubscribe : https://launchpad.net/~kicad-developers >> > More help : https://help.launchpad.net/ListHelp >> > >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~kicad-developers >> Post to : kicad-developers@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~kicad-developers >> More help : https://help.launchpad.net/ListHelp >> > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : kicad-developers@lists.launchpad.net > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp >
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