--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Wed, Aug 30, 2017 at 1:54 AM, Richard Wilbur <[email protected]> wrote: > Luke, > > Thank you ever so much for the clarification regarding perspective. > > Comments inline below. > > On Aug 22, 2017, at 12:25, Luke Kenneth Casson Leighton <[email protected]> wrote: >> >> okaay, wiggle-progress... 1st image is left end, i think CX and TX0 i >> can shorten even more, there's definitely plenty of space there, big >> gap. > > Shortening CX and TX0 is fine but I would cramp any > of the clearances to make it happen. there aren't any!! the GND separation vias see to that (attached). no there's not enough room to move those GND vias *in between* the VIAs, they need to be below, unfortunately. that means the diffpairs need to curve _round_ them (to the SW slightly). oops. actually it just occurred to me that i could move the HXT?P vias over by another.... 10-15 mil or so, which would mean that the corresponding HXT?N traces would be able to go straight (directly south) instead of SW, S then SE. phrrrrddhh :) > On the other hand, if you were to put them into a 45° > bend from south to southeast a little sooner, > we would probably have enough room to adjust the ground shield > trace on the southwest and west to abide by our 15mil differential > trace to "anything not in the same pair" clearance (specifically to HTXCN). well, unless i add a flood-exclusion zone (thoughts on that?) anything W or SW of HTXCN is going to get flood-filled with GND. or... i _could_ just put in a copper-to-diffpair Design Rule of "15 mil" clearance - that would keep the flood-fill away. >> anyway those wiggles are done by hand, some of them aren't pretty but >> in mil those traces are now nearly all to within 0.01 mil. i cheat a >> little and have made some of the corners in places a very very tiny >> arc, where you get better fine-grain control over the amount it takes >> off. > > Well done. ... i'm getting used to it.... >> HTXCN just before the diff-pair vias at the end i'm a little concerned >> about, it looks a bit too... sharp-angled to make me feel totally >> comfortable... not a lot of space... i tried a single wiggle and it >> went too far away from HTXCP for me to feel happy about it.... put in >> two much smaller wiggles instead... >> >> GND i'll remove as the absolute last thing. > > Sounds great. Only really want to remove the ground traces > that can't comply with the 15mil clearance between differential pair and > anything not in the same pair. marked in this image, i was planning to remove the GND traces that are marked with red dots.... but only after all's done because currently they help keep the inter-pair separation. does that sound sensible? l.
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