Sorry for confusion differential pair is on your board connecting rj45.

But what I mean is ethernet has issues with impedance and lenght of their
tracks.  Gpio connectors on AwSom EVB is not designed for high speed too,
so maybe you have a hardware issue between A20 and your emac PHY.

If you switch EMAC to port A and make it works you will know this is not a
software issue (EMAC ok with a tested and working hardware). I'm not sure
if PHY on AwSoM is emac compatible but I guess it is.

I don't think this issue is your problem (because you're not using gmac)
but take a look on this thread too:
http://lists.denx.de/pipermail/u-boot/2014-September/190239.html  Allwinner
gmac have some registers so change delays on clk line that helps some times
if track is not matching correct delay.

cheers,

 - Roberto

On Tue, Nov 11, 2014 at 9:55 AM, Николай Костенок <[email protected]>
wrote:

> I used A20 Datasheet V1.40.pdf
> And i see that emac can be mapped on port A and H.
> Port H8-11 and H14-27.
> Then i looked in A20-SOM-EVB_schematic.pdf and see that all this pins
> available on GPIO-3. And even V3.3 and GND which i used to suply PHY.
> What differential pairs you mean?
>
> вторник, 11 ноября 2014 г., 14:29:33 UTC+2 пользователь Roberto Alcântara
> написал:
>>
>> I'm using same modules but one ethernet only, so I cant help so much.
>>
>> But as gmac is compatible with emac I think you should try EMAC on port H
>> to test a board layout/phy that you know is ok.
>>
>> I think Awsom EVB do not have differential pairs on gpio-3, so maybe you
>> have a hardware issue.
>>
>> cheers,
>>   - Roberto
>>
>> But I think you should try to put EMAC on
>>
>> On Tue, Nov 11, 2014 at 2:55 AM, <[email protected]> wrote:
>>
>>> I have A20-SOM-EVB, but i need 2 ethernets. So i make external board
>>> with LAN8710 and RJ45 and connect it to GPIO-3 on A20-SOM-EVB. A20 has 2
>>> MAC (GMAC and EMAC).
>>> GMAC uses port A. And EMAC can use port A or port H(on my board on
>>> GPIO-3). I used Openwrt. Build kernel, fs u-boot and dtb. Checked thats
>>> GMAC is working. Then i make dts form dtb and modify it. I enable emac and
>>> set its pins to port H. But when i start both ethernets can see link, but
>>> can not even pings. Emac when trying pings send broken packets like:
>>> 6f:73:fe:96:6f:73:fe:96:6f:73:fe:96:6f:73:fe:96:6f:73:fe:96:
>>> 6f:73:fe:96:6f:73:fe:96:00:00:00:00:00:00:00:00:00:00:00:00:
>>> 00:00:00:00:00:00
>>> Sorry for my english.
>>> Anybody run 2 ethernets on A20?
>>>
>>> DTS:
>>> /dts-v1/;
>>>
>>> / {
>>>
>>
>>
>>
>>
>>  - Roberto
>>
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