DP83TD510E-EVM: DP83TD510E-EVM configuartion for media converter mode

Hello Michael McGlynn,

Thank you for the message.

The media converter should work without MCU. You need to change R24 to 0R and ensure J20 is in "Mode 0" position ( between pin 1 and pin 2).

Please refer to the below thread

 https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1032585/dp83td510e-evm-can-t-establish-link?tisearch=e2e-sitesearch&keymatch=DP83TD510E#

Regards,

Sreenivasa

Hi Sreenivasa

The link you posted seems to be dead, but I think I'd already read it. I had J20 in Mode 0 position and I don't think R24 was causing any problems as I'm not powering it from the USB port but I've shorted it anyway.

I modified one of the dev kits by removing R31 & 33 and disabling U3 so the MCU is diconnected from MDC & MDIO.

In everty other respect both dev kits are in default configuration.

I have one connected to an ethernet router at the PC end and the other is connected to the ethernet port of an arm based SOM running a minimal linux and CodeSys runtime.

Before disconnecting the MCU from the management interface the SOM obtained an IP address from the router and I could access the runtime on the SOM from the CodeSys IDE on the PC.

After disconnecting the MCU from the management interface it still works if the MCU-less media converter is attached to the router. If you swap the boards around though the IDE on the PC cannot connect to the Runtime on the SOM, although the SOM appears in the router's client list. I am perplexed.

Is there a requirement to reverse the master/slave configurations of the PHYs at one end?

Thanks,

Mike.

Hello Michael McGlynn,

Please refer to the link below.

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

May be i misread tour question.

What i meant was the media converter works without external MCU and any additional configuration.

The MCU performs MDIO interface to the two devices and also controls the device operation. 

Regards,

Sreenivasa

Hi Sreenivasa

The DP83TD510E datasheet suggests that no MDIO configuration is necessary:

The DP83TD510E provides option to enable media conversion ( Single Pair Ethernet to Standard 10Base-Te
CAT5e) functionality using strap configurations (no external MCU programming is needed). The DP83TD510E
can be connected to 10 Base-Te PHY (For example : DP83822, DP83826I) to covert the medium from Single
Pair Ethernet to Standard Ethernet(CAT5e). This can be done using RMII or RGMII mac interface can be used to
perform the media conversion.

The dev kit schematics aren't the easiest to follow, but the connections as detailed in the DP83TD510E datasheet appear to be in place. When I disconnect the onboard MCU from MDIO however, the links stops working. Am I missing something?

Thanks,

Mike.

Hello Michael McGlynn,

Thank you for the reply.

As i said in the above message, MCU has additional function along with the MDIO function  including reset and pwdn.

Regards,

Sreenivasa

Hi Sreenivasa

I'm aware that the onboard MCU provides additional functionality, my point is that the media converter SHOULD work without it, but apparently doesn't. I'm reluctant to proceed with my own design using these parts until the reason for this is determined.

I note in other threads that problems related to this have occurred where the phy on the dev kit is pre-production and e.g. requires registers to be set to correctly enable auto negotiation. Is there a way to determine if this is the case?

Is the code for the onboard MCU available?

Thanks,

Mike.

Hello Michael McGlynn,

Thank you for the message.

If you are expecting the media converter on the EVM to work by only isolating the MDIO signals i am not sure if the EVM has the capability.

To disable the MCU on the EVM , you will have to disable all the signals going to the PHY from the MCU. This may call for some additional changes.

When did you buy the EVMs. Would you be able to read the device ID? I have not has anyone having to do these updates recently.

I have not had any customer asking for the code. Let me check if it is available and can be shared.

Regards

Sreenivasa