Intel i210AT support for arbitrary MDI/RJ45 pair swaps?

[jdevans_jdevans]

Does the intel i210AT controller support MDI pair swaps?  I know that it can accommodate polarity inversion (P/N swapped) and TX/RX swaps (so pair 1 swapped with pair 2, pair 3 with pair 4, Auto MDI-X), but can it support pair 1-with-pair 4 and 2-with-3 swaps?  
  Some PHYs do - TI, for instance, has a "MIRROR MODE" in some of their PHYs that can support this as a configuration option.

  It looks like some of this arbitrary pin-swap support is part of the IEEE Gigabit Ethernet specification, but that would not apply for 10Mbit and 100Mbit connections...

Thanks, James

[IntelSupport]

Hi jdevans_jdevans,

Thank you for posting in Intel Ethernet Communities.

Regarding your inquiry, as you mention that "Some PHYs do - TI", can share with us what is TI stand for? Is it a model or brand name?

You may check on Intel® Ethernet Controller I210-AT Datasheet under section 2.3.6 PHY Pins as per link below and let us know if that information helps with your inquiry.

Intel® Ethernet Controller I210-AT Datasheet

https://cdrdv2.intel.com/v1/dl/getcontent/333016

If you have additional questions or clarifications, feel free to let us know.

Best regards,

Fariz_Intel

[jdevans_jdevans]

Thanks, I have the datasheet and it does not address this question.  
Regarding: "TI" - Texas Instruments is another vendor that sells 10/100/1000 Ethernet Controllers.  I mentioned their part because they clearly call out the capabilities in this regard with a separate proprietary mode that allows for these types of pin-swaps.

So, the question remains : Does the Intel i210AT controller support arbitrary pair-swaps for the copper MDI interface?
  There are 4 pairs of signals that go through magnetics to specific pins on an RJ45 connector.  The datasheet indicates MDI-X support for swapping the receive and transmit pairs (pair 1 swapped with pair 2, pair 3 swapped with pair 4) but does not address swapping pair 1 with pair 4 or pair 2 with pair 3, which is helpful when routing to certain RJ45 connectors that have the pin locations arranged in that configuration.
  If the controller supports these pair-swaps then the signals could be routed without the need for vias.  If the controller does not support these pair swaps, then the signal routing must transition between layers with vis to order the signals appropriately - which is not ideal for relatively high-speed signals.
Thanks,
James

[IntelSupport · Accepted solution]

Hi jdevans_jdevans,

Thanks for sharing the information.

We are sorry for the late response. After we check and review back the datasheet, the information for MDI pair swaps are available at Table 1-3. Network Features in MDI flip row on page 12.

MDI flip: I210 (N)

This mean MDI flip/MDI swaps is not allowed for I210, however for I350 is allowed based on the table.

There is also different model support for MDI swaps which is I225 and I226. You may refer Intel® Ethernet Controller I225/ I226 Product Brief as per below link which mention under features that it allowed MDI Lane Swap; a simple hardware strapping option that allows the ability to swap the MDI pairs order between ABCD<->DCBA. This reduces routing complexity and risk.

https://www.intel.com/content/www/us/en/products/details/ethernet/gigabit-controllers/i225-controllers/docs.html

Best regards,

Fariz_Intel

[Fariz_Intel]

Hi jdevans_jdevans,

If you have additional questions or clarifications, feel free to let us know. Thanks.

Best regards,

Fariz_Intel

[Fariz_Intel]

Hi jdevans_jdevans,

We are glad and hope this will help you. If you need any additional information, please submit a new question as this thread will no longer be monitored.

Best regards,

Fariz_Intel