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

[Luke Kenneth Casson Leighton]

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crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Thu, Aug 10, 2017 at 9:38 AM, mike.valk at gmail.com
<mike.valk at gmail.com> wrote:
> 2017-08-10 10:18 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:
>> On Thu, Aug 10, 2017 at 9:01 AM, mike.valk at gmail.com
>> <mike.valk at gmail.com> wrote:
>>> 2017-08-09 15:23 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:
>>> Make sure the'res as much solid GND on the layer above and below the
>>> traces, again shielding.
>>
>>  these are layer 1 and layer 6, and layer 2 and 5 are solid GND.
>
> I was referring mostly to layer 3 and 4. The diff pair is either on 3
> or 4.

 no.

> If it is on 3 a slab of GND should be on 4 and vice versa.
>
> It's
> 1. Vsuply + components
> 2. Ground
> 3. HF
> 4. HF
> 5. Ground
> 6. Vsuply + componnents
>
> Right?

 no.

1. SIG1 + components
2. Ground
3. SIG3
4. POWR
5. Ground
6. SIG6 + componnents

 there's only 3 signal layers: 1, 3 and 6.  there are NO HDMI
diffpairs on layer 3.  i'm not happy about the fact that i have to use
vias *at all* but there's no choice: layer 1 the 24mhz XTAL and the
PMIC are in the way, and when you get to the DC3 connector the signals
*have* to go round the back (layer 6) anyway.

l.