100baseT1 and 1000baseT1 Link Negotiation/Startup Process - Scope Capture

Hi,

We have a MSO70804C Mixed Signal Oscilloscope with the TekExpress compliance package and the automotive ethernet package.

Currently, as part of a debug process we would like to scope capture the link negotiation process happening between two of our ECUs. Is there a way to do this? Also, my major concern is how to set the scope to trigger at the Link Negotiation Process?

I would like to know what would be the best approach to capture this?

Thanks,
Midhun

Hi Midhun,

One of the trigger types available on your instrument is CAN Bus. You can tell the MSO70kC to trigger on a specific address or message.

So if you find a message in the link training algorithm that correlates with the problem you are debugging then you can trigger on that message type.

I think by default the TekExpress package attempts to configure all the horizontal, vertical, and trigger settings itself when you are using it. In that case it may be better to capture the .wfm waveforms on their own and then use TekExpress on those captured .wfm files.

Oh I'm sorry if it was not clear in the original post. The ECUs are connected using 1000BaseT1 automotive ethernet. I would like to scope capture the link negotiation process happening between two of our ECUs in this 1000BaseT1 automotive ethernet.

My mistake! Still, I think your best bet is to try different trigger settings. If it’s not CAN, then maybe the Serial trigger would work.

From the MSO70000C manual (p.72):

Trigger Selections

Serial                    Trigger on 64-bit NRZ serial pattern at data rates up to 1.25Gb/s and 4 8b/10b symbols at data rates up to 6.25Gb/s (MSO70000C/DX and DPO70000C/DX only). Requires option ST1G (DPO7000C) or ST6G (MSO70000C/DX and DPO70000C/DX). Includes clock recovery. Push the Push to Set 50% control to reinitialize clock recovery

Hi Midhun

Yes we have lots of customers coming to us with this issue. Automotive Ethernet, as you know, if a full-duplex signal over a signal twisted pair cable, meaning that both the primary and secondary ECUs will talk at each other. In order to view signals that are transmitted by each individual ECU you must first separate them. Traditionally this process has been done through the use of a directional coupler. However, Tektronix has developed a way to be able to separate these signals in a non-intrusive way, though the use of our split core current probes.

Here's a link to an application note where we discuss this further: https://www.tek.com/en/documents/application-note/automotive-ethernet-see-true-signal

And here's a link to a quick video where we demonstrate this capability in action: https://www.tek.com/en/video/product-demo/automotive-ethernet-signal-separation-demo

Please note that this feature is only available on our 5 and 6 Series MSO scopes