[Arm-netbook] HDMI High-Frequency Layout: Timing

[Luke Kenneth Casson Leighton]

On Tue, Aug 1, 2017 at 2:51 PM, mike.valk at gmail.com <mike.valk at gmail.com> wrote:

[trimming a huge amount of unnecessary context on your behalf, mike...
hint, hint....]

>>  there's a lot of other stuff in here which is really good, such as
>> making sure that lengths on each *layer* are matched, and that even
>> when turning corners the lengths are matched.  and matching just after
>> VIAs *not* before... damn
>
> Between via's the length should be matched right? Length mismatch
> should be solved as soon as possible to accommodate eddy-currents
> right?

 yes.  the toradex article explains it very well, also mentions the
importance of symmetry (as does the TI post).

> Found a nice post from TI
> https://e2e.ti.com/blogs_/b/analogwire/archive/2015/06/10/differential-pairs-four-things-you-need-to-know-about-vias

 nice!  dang, above 10ghz the thickness of the via starts to matter
and needs to be drilled out, post-production.  dang.

 *sigh* unfortunately symmetry is not completely achievable with the
drastically-reduced amount of space available.  the HDMI signals come
out right at the bottom of the board.

l.
>
>>
>>  so thank you - much to correct and think about.  really appreciated
>> you finding all this stuff richard.
>>
>> l.
>>
>> _______________________________________________
>> arm-netbook mailing list arm-netbook at lists.phcomp.co.uk
>> http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook
>> Send large attachments to arm-netbook at files.phcomp.co.uk
>
> _______________________________________________
> arm-netbook mailing list arm-netbook at lists.phcomp.co.uk
> http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook
> Send large attachments to arm-netbook at files.phcomp.co.uk