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
