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How do you test Ethernet? (Manufacturing)

Started by MatthewEshleman 2 months ago5 replieslatest reply 1 month ago73 views

Hi all,

During manufacturing, I am curious how different groups test Ethernet interfaces on their embedded products (when applicable), such as 1000BASE-T.

Is testing performed during PCB manufacturing?

Is testing performed during final product assembly?

How is the interface tested?

What level of testing was deemed adequate?  i.e do you Tx/Rx a million packets and check for packet errors, or just simply acquire an IP address via DHCP and call it good?

Thank you very much!

Matthew

https://covemountainsoftware.com/services/


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Reply by mbedDecember 7, 2020

In my experience, the ethernet testing involves:

- Loop back at Mac level (pcb level test)

- Loop back at Phy level  (pcb level test)

- Insert external loop back interface and test loop back at interface level (pcb level test)

- Hook to traffic generators and dump statistics (speed, accuracy tests)

- Auto negotiation test if Phy is configured for Auto negotiation

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Reply by MatthewEshlemanDecember 8, 2020

Thank you, good to know! Do you know of any good description of using/performing the external loop back test?

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Reply by matthewbarrDecember 8, 2020

Yes, much better, I've developed those test hooks and related phy/link tests for IEEE 802.3ae SerDes designs. Remote (vs. local) loopback capabilities are often a part of the DUT design and test picture as well. I wasn't able to implement that level of testing for the 1000BASE-T product, basic functional testing was deemed sufficient and the DFT hooks were not included in the design.

Different companies and management, with differing sensitivities to DFT, manufacturing process and quality control issues.

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Reply by matthewbarrDecember 6, 2020

Hi Matthew,

I have manufacturing test experience with one relevant product which consisted of a number of small board assemblies, one with a 1000BASE-T interface.

The PCB manufacturer did not perform any functional testing. The board level test which I owned and developed did rudimentary testing, it verified that the interface connected at the right speed, acquired an IPv4 address via DHCP and completed a small file transfer in the expected time frame. The final manufacturing test for the complete assembly used the Ethernet interface heavily. I have to confess that I don't know if it specifically verified data transfer rate and packet errors for reasonable sized file transfers, I think it did but I am not sure. We did not perform any Ethernet signal level or integrity testing.

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Reply by MatthewEshlemanDecember 8, 2020

Good to know, thank you!