Ethernet problems on Apalis imx6

Hi,
I’ve the problem that I can’t establish an ethernet connection on a new dev. custom baseboard.
The baseboard is build with fast ethernet, so the four unused lines are left open! Also the CTREF pin (46) on Apalis side!
Both LEDs, the link and the activity LED are still off.
The same Apalis modul works on Eval board with gigabit ethernet with no problems.

Can anybody confirm that there is no need to configure the fast ethernet!?
I think the problem is on hardware side.

Anybody an idea what I can check?

Does the carrier board follow our recommendations for implementing a 10/100Mbit Ethernet interface? You find the information in section 2.4.2.3 of our carrier board design guide

Leaving the center taps open is not an issue for the Apalis iMX6 since they are left unconnected on the module. Nevertheless, for compatibility with future modules, we recommend connecting the tap to the reference voltage pin of the module (pin 46)

What exactly are you connecting to the module? Is the other side able to do a auto negotiation for going down to Fast Ethernet? There is another test you could do: Use our evaluation board but use instead of a gigabit capable cable only a cable that connects only two of the four data lanes (the two that are used for Fast Ethernet). This test will proof that both sides are able to do the auto negotiation for falling back to Fast Ethernet.

thats strange I look to the datasheet of the network (gigabit) switch I work with! …all ports supports auto negotation…and other fast ethernet hardware work with this switch, due to I don’t put it into question!
I’ve taken another switch and with this it works now! :slight_smile:
Many thanks to @peter.tx you bring me on the right way!
Now we have to find out why our hardware solution don’t work with all network switches…may be some signal levels near the threshold value or another reason.

Make sure your switch is doing auto negotiation and no settings get overridden.

You could also use ethtool on the Apalis side to see whether or not the negotiation is attempted and what it is reporting. You may also force the PHY into FastEthernet only mode that way.

thanks for your reply…
how can I force the phy to fast ethernet mode? Are the mode pins of the micrel KSZ9031RNX accessible from iMX6?

Yes, as the mode pins are shared with regular RGMII_RXD pins. However by forcing I actually meant in software using ethtool. With the mode pins I guess you would first need to find out at what point in time one could influence them.

after system boot, I checked the eth0 settings with the ethtool and got the response that auto negotation is on and speed is set to 1000/full! So the autonegotation does not work with all switches! I set the speed with: “ethtool -s eth0 speed 100 duplex full” and the link goes up and work fine!

Is there a possibility to force the speed to 100 per default in uboot or kernel phy driver?

For Linux you could try in the device tree to add the max-speed property to the phy node.

Have a look in the following two files in the kernel tree:
Documentation/devicetree/bindings/net/phy.txt Documentation/devicetree/bindings/net/fsl-fec.txt

very nice… thx to @max.tx I set the speed in device tree and it works!
This workaround is ok for me!