MDIO Access fail alwase give MDIO read 0xFFFF .

Hi nikunj91 

Thank you for reaching out and sharing your schematic.

I'll get back to you after reviewing this with the team.

Regards,

Shazia

Hi nikunj91 

The schematic looks good and follows our recommendations. 

Could you confirm that media converter is working as expected? If the ADIN1100 is not powered correctly or if the clock is not provided correctly, the media converter will not function nor will the MDIO read/write. So if the media converter is working then we can rule this out.

Then the two possible issues could be:

1. Signal integrity of the MDIO - You've already provided a digital capture of the signal. Can you look at the signals with a scope using analog probes, so that can give a clear understanding of what the signal looks like?

2. Software driver porting - Connect to our evaluation board and check if you can communicate with the MCU. Also, verify if the MCU outputs the correct signals.

Regards,

Shazia

Hi Shazia,

I have a similar problem. The ADIN1100 is not responding to any PHY-Address, so it´s always returning 0xFFFF. MDC is working fine, as well as the RXCLK and the TXCLK. The LED_0 (Link LED) is ON and blinking, so a link is established. I´m adding a scope-picture of the MDIO-Communication with the PHY-Address 0x00, wich is selected by the PHYAD-Pins on startup, but the transmitted data looks the same on every other PHY-Address.

A pull-up resistor has been added to the MDIO-Pin and all MII-Interface wires are directly connected to the MAC-Chip. PIN 25 also outputs low.

Regards,

Jannis

Hi Jannis 

Thank you for sharing the schematic.

The 27pF capacitor value (C212, C213) used exceeds the specified crystal load capacitance range of 10-18pF for the 25MHz clock, as outlined in the datasheet. Please refer to the datasheet for further details.

Regards,

Shazia

Hi Shazia

Thanks for your answer.

I have already tried it with a 15pF capacitor as nikunj91 did, but it didnt work. There has to be something different but I have no Idea what it could be. The clock and the Link LED are working so the ADIN1100 is communicating, but still doesn't respond to the MAC.

Can you think of something else that could be wrong?

Regards,

Jannis

Hi Jannis 

Have you tried verifying with our eval board as mentioned above?  

Software driver porting - Connect to our evaluation board and check if you can communicate with the MCU. Also, verify if the MCU outputs the correct signals.

Regards,

Shazia

Dear Shazia,

Yes media converter application looks working ,

Please find MDIO and CLK signals ,

I check BaseT1L signal that also looks ok .

can you please verify 25MHz Clock Signal is that ok ? 76mV Pk-Pk ?

Regards,

Nikunj

Hi Shazia,

I don't have an MCU, I have a MAC-Chip connected to the ADIN1100 on one side (MII-interface), and on the other side i have an ethernet connection. The MAC-Chip is working fine and is communicating with the PC. It also sends the correct signals but it doesn't get any answer to any Phy-Address from the ADIN1100.

I also tried communicating with the Ethernet via your Eval-Board and it worked, so the drivers are working fine.

Regards,

Jannis

Hi Shazia,

i test with ADIN1100 EVM and from EVM i can access to my custome board so it must be something in MDIO implementation .

is there any EVM MCU SW availabe so we can check MDIO implementation .

Regards,

Nikunj

Hi nikunj91  Jannis 

Thank you for sharing the details.

 nikunj91 - Can you confirm the clock frequency for MDC? The plots you shared - do they show MDC clock or the MII interface clock?

Can you provide the schematic for the MCU side? Are both of you using a MAC to connect to the ADIN1100? Also, could you confirm whether you're using SPI or bit banging for MDIO/MDC?

We can provide you access to an example, including guidance on porting the MDIO driver to any MCU. 

Kind regards,

Shazia