DP83869HM: Destination host unreachable/Request timed Out

Hi Rajesh,

Please send me a register dump from the PHY including register 0x00-0x1f, 0xC00-0xC08, and 0x6E. I can have a look at your schematic as well if you can share it.

Thanks,

David

Hello David,

Thanks for reply!!!

Please find the register dump from the PHY including register 0x00-0x1f, 0xC00-0xC08, and 0x6E. 

Schematic:

1321.Ethernet Section.pdf

Regards,

Rajesh

Hi Rajesh,

Register 0x1 shows link is down. Has it ever been up? If so, please send me a register dump in this case. 

Thanks,

David

Hello David,

Thanks for reply!!!

Yes, it has been up, whenever I connect board to board test that time link is up, below is result

0x1:

Regards,

Rajesh

Hi Rajesh,

Please send me the same register dump in the link up scenario.

Thanks,

David

Hello David,

Thanks for reply!!!

PFA of same register dump in the link up scenario. I did the compression of (non-operational and operational) those register values are the changes.

1.0001 = 796D

2.0005 = CD81

3.0006 = 006F

4.0008 = 4806

5.0011 = 7C02

6.0013 = 1C44

0x00-0x1f:

00xC00-0xC08, and 0x6E:

Regards

Rajesh 

Hi Rajesh,

I will go through the schematic and register dump and get back to you next week. 

Thanks,

David

Hello David,

Any update on Schematic and register dump?

Regards,

Rajesh R

Hi Rajesh,

It looks like there is a difference in link partner between the two cases, or that a cable is not installed at all in the fail case. Register 0x6 shows us the link partner is not auto-negotiation able. Register 0x8 shows there is no acknowledgement from the link partner. The register dump looks at if no link partner is connected at all. Is anything about the setup different between these two cases?

I see there are several comments on the schematic. Were these changes implemented? Please send me an updated schematic if so.

I noticed in that the magnetics are not what we recommend in the datasheet. The center taps should not be connected nor tied to VDDIO, and the capacitor values are different. This is likely contributing to the issue. 

Thanks,

David

Hello David,

Thanks for replying!!!

1.It looks like there is a difference in link partner between the two cases, or that a cable is not installed at all in the fail case. Register 0x6 shows us the link partner is not auto-negotiation able. Register 0x8 shows there is no acknowledgement from the link partner. The register dump looks at if no link partner is connected at all. Is anything about the setup different between these two cases?

ANS:  The configuration is set to forced 100mbps media converter as per the data sheet. Therefore, auto negotiation was not selected as per datasheet. 

ANS:  Link partner does come up at certain times when we had successful ping. This means setup is okay. 

2. I see there are several comments on the schematic. Were these changes implemented? Please send me an updated schematic if so.

ANS: Below is the Updated schematic 

SCHEMATIC1 _ 07-PHY SECTION.pdf

3. I noticed in that the magnetics are not what we recommend in the datasheet. The center taps should not be connected nor tied to VDDIO, and the capacitor values are different. This is likely contributing to the issue. 

ANS: Already in TI forums one person using same RJ45 connector (7499111121A) with 1000base-TX to 1000base FX it's working fine in our schematic we used 100baseTX to 100base FX with same RJ45 connector (7499111121A). Below is the 1000base-TX to 1000base FX sch. FYR Media_Converter_1000BaseTX to 1000BaseFX.sch.pdf

Regards,

Rajesh R

Hi Rajesh,

All the register dumps you have sent show auto-negotiation is enabled in the DP83869 (register 0x0000 has value 0x3100). If you force the speed on the link partner side while leaving auto negotiation on on the DP83869 side, they will not link up. Please leave auto negotiation on on both sides of the link. 

What E2E thread are you seeing that approves the 7499111121A magnetics? We do not recommend center tap connected magnetics, as shown in figure 111 of the datasheet.

Thanks,

David

Hello David,

Thanks for replying!!!

 In current design we used (Part: no: 7499111121A) RJ45 connector. Please confirm this connector is an issue? and below is the connector datasheet & image.

7242.7499111121A_RJ45_Connector_datasheet.pdf

Kindly confirm ASAP

Regards,

Rajesh 

Hi Rajesh,

We do not recommend center tap connected magnetics as shown in figure 111 of the datasheet, so I cannot recommend the 7499111121A part. This may be the cause of link issues you are seeing. Please use one that meets the requirements listed in section 10.2.1.2.2 and figure 111.

Thanks,

David