DP83TD510E-EVM: Can't communicate through a pair of DP83TD510E-EVM as media converters.

Hello Mathieu

Thank you for the query.

There are some hardware changes. To start with you will have to change the R24 to 0R from 33R.

https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1032585/dp83td510e-evm-can-t-establish-link/3822004#3822004

Regards,

Sreenivasa

Hi Sreenivasa,

I understood from other support posts that R24 only mattered when using the USB-2-MDIO interface?

I can't open the link you have posted.

Edit: I would like to add that we have no experience with soldering and desoldering SMD components. So we would like to avoid that if possible.

Best regards,

Mathieu

Hello Mathieu

Thank you for the reply.

Can you please apply external voltage and check   the DC voltage across C62,  C70 and the clock at R149.

FYI, These are the changes required

replace R24 with a 0 Ohms Resistor to power it only through the USB-Port, 

 Please check the DC voltage across C62 and C70.

Check the clock at R149

Perform a reset using S4.

Further debug:

If there is no clock on R149 it Seems like the DP83822 is getting no clock signal at all.  You may need to check configuring the register through MDIO interface.

USB-2-MDIO 

3.4 SMI Connection

In Media Converter configurations, the MDIO/MDC lines of the DP83TD510E and DP83822I are tied together. Both PHYs can be accessed simultaneously. The DP83TD510E has been set to PHY address 00 and the DP83822I has been set to PHY address 05. • Connect micro-USB to J4

Please go through the section 4 Software of the user guide.

In default state the DP83TD510E register 0x0017 bit 7 is set to "XI is 50Mhz". Change that to "XI is 25Mhz" and it will result in a clock signal on R149. 

In short: Write "4021" to the register "0017" on the DP83TD510E and you will be able to communicate to the DP83822 over SMI.

Regards,

Sreenivasa

Hi Sreenivasa,

I'll need some more time to check the things you mentioned and to apply the changes you proposed (I'll get some help from colleagues with the SMD components).

In the meantime I was just testing again, by changing the J20 jumper on both boards to 0 (all other jumpers in default position).
For some reason the communication started working now.

Very strange since it didn't work earlier with the same configuration, so to be sure I rebooted everything, now it doesn't work anymore and I didn't change a thing...

On one board, the DP83822 LED_0 turns on, a second later the RJ45 link LED turns on and the DP83822 LED_0 turns off.
On the other board, the DP83822 LED_0 turns on and stays on, the RJ45 link LED never turns on.

I already switched the RJ45 cables to exclude issues with those cables or devices, but it stays the same. The RJ45 link on one board becomes active, on the other board the RJ45 link remains inactive.

As I said above, I'll need some more time for debugging and applying the changes, it won't be before the end of the year.
We also have some strange issues with a pair of DP83TC811EVM (100BASE-T1 evaluation modules) but that's for an other post and an other day.

Thank you for the answers and I'll get back to you once I'm done debugging.

Best regards,

Mathieu

Hello Mathieu

Thank you for the message. Can you please remove the J20 and check the communication.

Regards,

Sreenivasa

Hello Mathieu

After power-up S3 and S4 can be used to perform the reset ad check the communication.

Regards,

Sreenivasa

Hello Mathieu

Good to hear. 

Please let us know the  DP83TC811EVM (100BASE-T1 evaluation modules) related issues. We will provide the required support.

Regards,

Sreenivasa

Hello Mathieu

Good morning. 

Would you mind writing a few lines on how you are testing the communication.

Regards,

Sreenivasa

Hi Sreenivasa,

We research industrial communication, so we are interested in the signal levels of 10BASE-T1L. We are also going to try to decode the communication using oscilloscopes and MATLAB (we're already decoding 100BASE-TX for years, 100BASE-T1 is in progress, 10BASE-T1L is next).

Best regards,

Mathieu

Hello Mathieu

Thank you for the inputs. 

My question was more about the communication testing you did on the two boards.

Regards,

Sreenivasa

Hi Sreenivasa,

We don't really do in depth testing of the boards and PHY chips themselves, it is enough for us that they work as media converters.

We are more interested in the communication itself and since there are no industrial components with 10BASE-T1L available at the moment, we bought these evaluation modules.

Best regards,

Mathieu

Hello Mathieu

Thank you for the inputs.

Could you please summarize the setup you used to test the media converter ? Tools used to send and receive the packets, ec.

Regards,

Sreenivasa

Hi Sreenivasa,

We just put them in between two Siemens Scalance X208 Industrial Ethernet Switches in a PROFINET network (industrial ethernet protocol).

Best regards,

Mathieu

Hello Mathieu

Noted and thank you. Do let me know if you have any additional questions.

Regards,

Sreenivasa

Hello Mathieu

Thank you for the inputs. I am closing the thread.

Regards,

Sreenivasa