DP83869EVM: Testing of 10/100/1000 Mbps Ethernet MAC to 100Base-FX and 1000Base-X Media interface

Hi Nikunj,

The media converter setting are specified in the DP83869EVM userguide:
https://www.ti.com/lit/ug/snlu237/snlu237.pdf?ts=1673376857010&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FDP83869EVM

Nikunj Mehta said:

limitation of this test was i can't change speed at Ethernet side now i need 10/100/1000 Mbps speed with both Media Inerface over the fiber 100Base-Fx and 1000Base-X

Can you please elaborate on what you are trying to achieve? 

Thanks,
Rahul

Hi Rahul,

I need 10/100/1000 Mbps speed at Ethernet side . and that can support for both option 100Base-Fx SFP and 1000Base-X SFP ( i will change SFP module accordingly ).

(it hase to work with any speed at ethernet side and support 100Base-Fx Or 1000Base-X over the Fiber i am not sure this is possible or not )

as per the 1000 Mbps Media Converter and 100 Mbps Media Converter Mode it hase to match speed at both side ( copper and optical ) .

i think if i select RGMII to Fiber/copper ( special use case ) mode Mention in 1.11 section of snla318 document then i can acchive my above requirement but i am not sure please share your thought .

https://www.ti.com/lit/an/snla318/snla318.pdf?ts=1673422108457&ref_url=https%253A%252F%252Fwww.google.com%252F

Let's discuss what i need

- i need converter that can communicate with network switch over SFP .

- so connection shoud be like below image

I know that it will alwase work if i have both side same setup with EVM .

Referance :-

as per the datasheet Section 9.4.2

https://www.ti.com/lit/ds/symlink/dp83869hm.pdf?ts=1673422276286&ref_url=https%253A%252F%252Fwww.google.com%252F

it is not supported for changing the speed in 1000Base-X and 100Base-FX as Both sides of the link must be configured to the same operating speed

but in Serial GMII it is possible to change the speed Section 9.4.3 in datasheet

The 1.25-Gbps rate of SGMII is excessive for 100-Mbps and 10-Mbps operation. When operating in 100-Mbps
mode, the PHY elongates the frame by replicating each frame byte 10 times and when in 10-Mbps mode the
PHY elongates the frame by replicating each frame byte 100 times. This frame elongation takes place above the
IEEE 802.3 PCS layer, thus the start of frame delimiter only appears once per frame.
The SGMII interface includes Auto-Negotiation capability. Auto-Negotiation provides a mechanism for control
information to be exchanged between the PHY and the MAC. This allows the interface to be automatically
configured based on the media speed mode resolution on the MDI side. In MAC loopback mode, the SGMII
speed is determined by the MDI speed selection. The SGMII interface works in both Auto-Negotiation and forced
speed mode during the MAC loopback operation. SGMII Auto-Negotiation is the default mode of the operation.

But in SGMII mode protocol not compatible with Standard SFP which are avalable at Network side.

What should be the right design for my requirement.

Thank you ,

Nikunj

Hi Nikunj,

Thank you for your detailed response, I believe I have a better understanding of your application now.

Media Converter mode:
As you mentioned this cannot be a solution for your application, as the speed should be same on both ends that is Copper side and Fiber side.

Your application topology as just a converter:

If my understanding is correct, the above setup should help with your converter application to connect to a network switch.

Please let me know if you have further queries.

Regards,
Rahul

Hi Rahul,

I am here to reply for Nikunj. The comments are put below:

Thank you Rahul for your replay.

1) regarding the below image as Media Converter mode

Can you please suggest me if this type of configuration available in TI with some App note Or Design guide.

2) lets discuss further on my application with the EVM setup

Note - SFP module details - "AC-SFP-SX-E - 1GBit/s 2 x MM OM2, max 550m, 850nm"
can this setup work as i change the fiber speed with 100Mbps and as switch has auto neg. it will automatic switch to 100Mbps mode ( as fiber speed is 100Mbps even though it was 1000Base-X ) . is it right ?

as per the  https://e2e.ti.com/support/interface-group/interface/f/interface-forum/842985/dp83869hm-media-converter-mode-for-copper-to-fiber?tisearch=e2e-sitesearch&keymatch=DP83869EVM# topic
100M Copper <> Eval Board #1 (DP83869EVM with strap config only) <> 1000M Fiber SFP(1000Base-X supported SFP ) <> Fiber Cable <> 1000M Fiber SFP(1000Base-X supported SFP ) <> Eval Board #2 (DP83869EVM with strap config only) <> 100M Copper

( with considering configure the Fiber speed to 100M )
this setup is working
in my application i need only one change .
100M Copper <> Eval Board (DP83869EVM with strap config only) <> 1000M Fiber SFP(1000Base-X supported SFP ) <> Fiber Cable <> 1000M Fiber SFP (1000Base-X supported SFP )<>Network Switch that can support 10/100/1000M speed.
(is it possible ? Or we required same configuration setting at both end for just because of evm implements some special configuration "When operating in 100-Mbps mode, the PHY elongates the frame by replicating each frame byte 10 times This frame elongation takes place above the IEEE 802.3 PCS layer, thus the start of frame delimiter only appears once per frame" Mention in DP83869HM Datasheet 9.4.2 and 9.4.2 ) Or some other reason like "SGMII Auto-Negotiation are different than the 1000BASE-X Auto -Negotiation" ( as 1000BASE-X Auto -Negotiation standard applies in SFP base Network switch . )

Note :- 100-Mbps mode, the PHY elongates the frame by replicating each frame byte 10 times ( is this frame replication apply even though i change speed at fiber side ? ) , is there any configuration available in smart SFP base network switch to communicate even though applying replicating in PCS layer )
Thank you for your help i hope you have clear idea what i need in my application with only one DP83869 communicate with Network speed ("special mode " fix 100Mbps at Ethernet and 1000Base-X SFP module at both side EVM and Network switch ).

Regards,

Nikunj

Hi Chong Yu,

Chong Yu said:

Can you please suggest me if this type of configuration available in TI with some App note Or Design guide.

We do not have an appnote or design that goes through this application.

For the remaining comments, please give me some time to go through different test case scenarios and other E2E post you have shared. I will try to debug more on this issue and share my feedback next week.

Thanks,
Rahul

Hi Chong Yu,

I have done tests for the following topology:

100 Mbps speed ( fixed ) --> 1000Base-X supported SFP <---> optical cable --> 1000Base-X SFP --> Network switch ( 10/100/1000 mbps supported )

Here are my findings, I have highlighted all the working setups in BOLD:

Test1:

PC (10/100/1000) <-> (869 100M media converter) <-> Gigabit SFP Module <-> Optical Cable <-> Gigabit SFP Module <-> Network Switch (10/100/1000)

PC (100M forced) <-> (869 100M media converter) <-> Gigabit SFP Module <-> Optical Cable <-> Gigabit SFP Module <-> Network Switch (10/100/1000)

- In this above topology no Link is noticed, but when I force the Network switch to 100M speed, then whole setup works. Following is the setup:
PC (10/100/1000) <-> (869 100M media converter) <-> Gigabit SFP Module <-> Optical Cable <-> Gigabit SFP Module <-> Network Switch (100M forced)

PC (100M forced) <-> (869 100M media converter) <-> Gigabit SFP Module <-> Optical Cable <-> Gigabit SFP Module <-> Network Switch (100M forced)

Test2:

Below test setups also work:

PC (10/100/1000) <-> (869 1000M media converter) <-> Gigabit SFP Module <-> Optical Cable <-> Gigabit SFP Module <-> Network Switch (10/100/1000)

PC (100M forced) <-> (869 1000M media converter) <-> Gigabit SFP Module <-> Optical Cable <-> Gigabit SFP Module <-> Network Switch (10/100/1000)

Regards,
Rahul

Hi Rahul ,

it is similer testing as topic https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1186434/dp83869evm-dp83869evm-interfacing-with-network-switch/4484876#4484876

i will cole this case with solution as per above case once i get setup image and Phy Read value.

Regards,

Nikunj

Hi Nikunj,

Sure, I will share them with you tomorrow.

Regards,
Rahul