DP83869HM: 100M Media Convertor Strap

user6150189

Part Number: DP83869HM
Other Parts Discussed in Thread: DP83869

I want to convert 100 base-TX and 100 base-FX with DP 83869 HM. (Use as a Media Converter)

I set strap as follows.
However, it cannot communicate well.

*Datasheet Table 12. Functional Mode Strap Table
JTAG _ TDO/GPIO _ 1 (OPMODE _ 0) 1
RX _ D3 (OPMODE _ 1) 0
RX _ D2 (OPMODE _ 2) 1

*Datasheet Table 17. 100 M Media Convertor Strap Table
LED _ 1 (ANEGSEL _ 0) 0
LED _ 2 (ANEGSEL _ 1) 0
RX _ CTRL (MIRROR _ EN) 0
RX _ CLK (LINK _ LOSS) 0

What are the factors? (Register setting, etc.)

When the output signals from the SON and SOP jacks were observed with an oscilloscope, 1.25 Gbps signals were output. Does it work as SGMII or 1000 BASE-X?

If you look at "1.7 100 Mbps Media Converter" in the following URL, the setting of LED _ 1 and LED _ 2 is shown only in [1]. Should LED _ 1 and LED _ 2 be set to [1]?

www.ti.com/.../snla318.pdf

over 4 years ago

0 Cecilia Reyes over 4 years ago

TI__Genius 9920 points

Hello,

Can you share what you mean when you say it does not communicate well? Do you see a link between your devices?

Media conversion only works from 100/1000BASE-TX to 100/1000BASE-FX

The register settings are available in the media converter section of our datasheet.

Thanks,

Cecilia

0 user6150189 over 4 years ago in reply to Cecilia Reyes

Intellectual 460 points

Hello,

>Can you share what you mean when you say it does not communicate well?
>Do you see a link between your devices?

I want to communicate between PC _ A and PC _ B in the communication system shown below.

But there is no ping between PC _ A and PC _ B.

Note that the DP 83869 HM is set to the [100 M Media Convertor mode] only by the Strap Configuration.

PC _ A - Ethernet Cable (100 BASE-TX) - DP 83869 HM - Coaxial Cable (100 BASE-FX) - DP 83869 EVM - Ethernet Cable (100 BASE-TX) - PC _ B

Note that the ping between PC _ A and PC _ B was successful when set to [SGMII to Copper mode].

PC _ A - Ethernet Cable (100 BASE-TX/1000 BASE-T) - DP 83869 HM - Coaxial Cable (SGMII) - DP 83869 EVM - Ethernet Cable (100 BASE-TX/1000 BASE-T) - PC _ B

[Question]
1.Is it possible to operate [100 M Media Convertor mode] only with Strap Configuration?

2. If it works only with Strap Configuration, is the following setting correct?

Table 12. Functional Mode Strap Table
JTAG _ TDO/GPIO _ 1 (OPMODE _ 0) 1
RX _ D3 (OPMODE _ 1) 0
RX _ D2 (OPMODE _ 2) 1

Table 17 100 M Media Convertor Strap Table
LED _ 1 (ANEGSEL _ 0) 0
LED _ 2 (ANEGSEL _ 1) 0
RX _ CTRL (MIRROR _ EN) 0
RX _ CLK (LINK _ LOSS) 0

Thanks,

0 Adrian Kam over 4 years ago in reply to user6150189

TI__Expert 5425 points

Hello,

Cecilia is currently out of office and will respond back tomorrow.

Regards,

Adrian Kam

0 Cecilia Reyes over 4 years ago in reply to Adrian Kam

TI__Genius 9920 points

Hello,

Thank you for your questions. The DP83869 can work as a media converter through straps however some register writes may be required.

As mentioned, the straps and register writes are available in our datasheet.

Can you please share the block diagram of how you are testing your communication between PCs? I am trying to understand what medium each PC requires and where the DP83869 is and what is being converted.

It is confusing to me that you are seeing the SGMII to copper mode working.

Thanks,

Cecilia

0 user6150189 over 4 years ago in reply to Cecilia Reyes

Intellectual 460 points

Hello.

The block diagram of the test system is shown below.

PC_A（100Mbps,Full-Duplex） - Ethernet Cable - DP83869EVM - Coaxial Cable - DP83869EVM - Ethernet Cable (100 BASE-TX) - PC_B（100Mbps,Full-Duplex）

- The NIC setting for PC _ A and PC _ B is set to 100 Mbps (Full-Duplex).

- Communication between PC _ A and PC _ B is evaluated using a tool called Iperf.

- An Ethernet cable is used to connect the PC to the DP 83869 EVM.

- A coaxial cable is used to connect the SON/SOP/SIN/SIP terminals between the DP 83869 EVM.

With the [USB-2-MDIO software], write the register of DP 83869 EVM as follows:

Communication between PC _ A and PC _ B was possible with 100 BASE-FX.

　01DF 0005
　0000 1140
　0010 5048

In order to simplify the system, I would like it to function as a 100 M Media Convertor Mode with only strap resistance without writing to registers. Is that possible?

Thanks.

0 Cecilia Reyes over 4 years ago in reply to user6150189

TI__Genius 9920 points

Strapping should be ok, however I do recommend being able to access our MDIO and MDC for register writes for debugging purposes in the future.

You are mentioning coaxial however I want to confirm if you are using fiber optic cables or coaxial and if you are actually using the mode in SGMII to copper or Media converter?

Typically with media converter you are connecting to an SFP on the other end so I would really appreciate the clarity.

Thanks,

Cecilia

0 user6150189 over 4 years ago in reply to Cecilia Reyes

Intellectual 460 points

Hello.

I understand that it is better to have MIDO and MDC for register writing for debugging in the future.

Since 100 base-fx is an LVDS interface, it is assumed that it can operate directly on the same axis without using SFP.

We are using the evaluation system (Evaluation system using 2 DP 83869 EVM substrates) mentioned above, but there is a phenomenon that we cannot understand.

Symptoms are as follows:.

--------------------------------------------------------

----------------------------

1.Set the strap to [SGMII-to-Copper Mode] (A) and do not write register (C) - > PC _ A and PC _ B can communicate on 1Gbps

2.Set the strap to [SGMII-to-Copper Mode] (A) and write the [100 M Media Convertor Mode] register (C) - > PC _ A and PC _ B can communicate at 100Mbps

3.Set the strap to [100 M Media Convertor Mode] (B) and write the [100 M Media Convertor Mode] register (C) - > PC _ A and PC _ B cannot communicate.

4.Set the strap to [100 M Media Convertor Mode] (B) and do not write register (C) - > PC _ A and PC _ B cannot communicate.

----------------------------

(A) : [SGMII-to-Copper Mode] Strap setting
Table 12. Functional Mode Strap Table
JTAG _ TDO/GPIO _ 1 (OPMODE _ 0) 　1
RX _ D3 (OPMODE _ 1) 　1
RX _ D2 (OPMODE _ 2) 　0

----------------------------

(B) : [100 M Media Convertor Mode] Strap Settings
JTAG _ TDO/GPIO _ 1 (OPMODE _ 0) 　1
RX _ D3 (OPMODE _ 1) 　0
RX _ D2 (OPMODE _ 2) 　1

----------------------------

(C) : [100 M Media Convertor Mode] register setting (With USB -2 - MDIO software)
Register01df is: 0005
Register 0000is: 1140
Register0010is: 5048

----------------------------

--------------------------------------------------------

As a result of the above, I think the Strap setting in [100 M Media Convertor Mode] mode is wrong. Is there any possible cause?

Thanks.

0 Cecilia Reyes over 4 years ago in reply to user6150189

TI__Genius 9920 points

Hello,

Please review this E2E question below in regards to media conversion with the DP83869. Please ensure that your signal detect is connected as well as it is required for the media conversion operation. My guess is that if your Signal Detect is not connected properly that can be causing issues with the communication at 100M

Another thing to note is that you will have to strap fiber speed to copper speeds since there is no way to negotiate speeds between both mediums

0 user6150189 over 4 years ago in reply to Cecilia Reyes

Intellectual 460 points

Hello

Thank you.

When we connected Signal Detect to ground, we were able to confirm the communication between PC _ A and PC _ B with only the strap terminal [100 M Media Convertor Mode].

Thanks

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DP83869HM: 100M Media Convertor Strap