Ethernet cable length limited to < 20 cm on IMXRT-1050-EVKB AVB demo

[usala]

Found the following errata for the IMXRT-1050-EVKB

MIMXRT1050-EVK ethernet back-to-back doesn’t work with long cables The issue has only been observed in back-to-back and using a < 20 cm cable fixes the problem.

(See attachment)

Are there any plans to fix this issue?

Best regards,

Usala

[usala]

Daniel,

I used a 6 inch cable (<20 cm) and the demo runs okay.  Both the talker and the listener's links come up and you can seen the RJ54 LEDs active.

When I try to connect the talker to a 100Base-T1 connector of a K2L Optolyzer MOCCA LAN the link never comes up.  If I take the Ethernet cable from my PC's from our network and plugged into the Optolyzer the LEDs become active and the link comes up as expected.  Is the demo designed to work among demo boards only?

Best regards,

Ulises

[danielchen]

Hi @usala :

Did you configure the network settings on the board to something appropriate for the Optolyzer (see section 2.6 of the NXP_GenAVB_TSN_Stack_FreeRTOS_Eval_User_s_Guide document)? Or reconfigure the Optolyzer to align with the board settings? 

Regards

Daniel

[usala]

Hi Daniel,

Yes I configured it as described in section 11.1 of the user's manual and got the demo to work when talker is connected to the listener I can hear the sounds from the microphone on the talker in the headphones on the listener.  But if I connect this working demo to the Optolyzer sniffer it doesn't drive the Ether port.  So I connected the demo board to a hub and it drive the hub okay.  So as a solution (workaround) I feed the hub to the Optimyzer and that works.  It seems like the hub is acting as a signal amplifier.  Interesting!

Best regards,

Ulises

[danielchen]

Hi Usala:

That is interesting. As there are known issues with longer cables on the RT1050EVKB, using the hub as an amplifier does seem to fit.

I'm comparing the RT1050 and RT1170 schematics, and the 10/100 circuit is pretty much the same. There are some DNP pull resistors and caps on the TXP/TXM and RXP/RXM lines. They are there for both boards though. The layout for the designs is different, so it could be that something in the layout is having an effect on the robustness of the ethernet interface.

Regards

Daniel

[usala]

Hi Daniel,

I have found a workaround for the PHY issue and I let Daniel know about it.  I used a Ethernet HUB to boost the signal and that seems to work.  The next step for me is to send the talker's sound through onto an automobile's amplifier.  I have followed the same procedure as when the talker sends the microphone's sound onto the listener.  I don't have access to the amplifier's stream ID but have the hw address.  The talker ID for the amp should be 0x00049f6ac5a80000 using MAC[3,4,5] at bytes 3,4,5.
based on amplifier's MAC : 00:50:C2:6A:C5:A8.

Here is the configuration based on information gathered from the sniffer.

AVB>>cd port0
AVB>>pwd
/port0
AVB>>write ip_addr 169.245.33.159
AVB>>write hw_addr 00:50:C2:6A:C5:A8
AVB>>write gw_addr 169.245.1.1
AVB>>cat ip_addr
169.245.33.159
AVB>>cat hw_addr
00:50:C2:6A:C5:A8

I am getting "port(0) stream_id(0000aabbccddeeff) MSRP_ATTR_TYPE_TALKER_FAILED MRP_ATTR_EVT_MT EGRESS_PORT_IS_NOT_AVB_CAPABLE"

I have attached a log capture from the talker.

Best regards,

Ulises

[danielchen]

Hi @usala :

Sounds to me that the hub that is being used is not AVB capable. For the stream to be established properly, it's not only the nodes, but any switches or hubs in between also need to be AVB/TSN capable.

Can you ask him about the hub. Additionally, is it possible to get a full diagram of his setup including where and how the sniffer is connected?

Regards

Daniel

[usala]

Hi Daniel,

IT was a regular Ethernet switch not AVB capable.  The demo kit is not capable of driving the PHY on a AVB capable device and is needed some boosting.  Adding an non-AVB capable switch allowed to amplify the signal and drive the PHY on the AVB capable device but it did not work as you mentioned because the interface between the Eval kit and the the AVB capable device in non-AVB.

What if we connect an AVB capable switch in between the eval board and the AVB capable device just to drive the PHY.  Will it work? And is there a particular AVB switch brand and model that you recommend?

Best regards,

Ulises

[danielchen]

Hi @usala :

Yes, an AVB or TSN capable switch would be what you need. Cisco AVB capable switches are a safe choice. I also found this brand that I have heard good things about:

https://motu.com/products/avb/avb-switch

Generally speaking AVB switches can be expensive, but if you are going to be doing development with AVB, it makes sense for them to have one.

Regards

Daniel

[usala]

Daniel,

Thanks for the advice.

Best regards,

Ulises

[danielchen]

Hi @usala :

We don't have any plans to do a different revision of the RT1050-EVKB. The ENET PHY is what drives the cable, so this sounds like it is probably a PHY issue rather than something with the processor itself. If you use a different PHY in your own design, I would expect that to resolve the issue.

Regards

Daniel

[usala]

Hi Daniel,

Thanks for your response.  We will take your advise and use a different PHY.

Best regards,

Ulises