DP83869HM: DP83869HM with AM2434

Andrea Favero

Prodigy 140 points

Part Number: DP83869HM
Other Parts Discussed in Thread: AM2434, DP83869

Tool/software:

Hello experts,

I'm working on a custom board that uses AM2434 with DP83869 PHY for industrial ethernet application.

LP-AM243x reference design is being used as a starting point to design the new board.

A multiplexer (TS3DDR3812RUAR) is used on the LP to connect the CPSW or PRG RGMII pins of the MCU to the PHY.

The custom board is going to use the ethernet for industrial ethernet applications only (profinet, ethercat, ethernet/IP, modbus TCP/IP...);

the question is: do I need to use a mux to connect both the CPSW and PRG RGMII pins to the PHY or is it sufficient to connect only the PRG RGMII pins?

Thank you,

Andrea

over 1 year ago

0 Hillman Lin over 1 year ago

TI__Mastermind 25955 points

Hi Andrea,

If possible, could you send a block diagram on what you planning to design for more clarity?

If my understanding is correct, you are looking for an MUX on RGMII interface. We don't recommend because due to the impedance matching and length matching of the MAC interface. We do have a layout checklist on what we recommend for RGMII interface.

7206.Industrial_PHY_Layout Review Checklist.xlsx

Regards,

Hillman Lin

0 Andrea Favero over 1 year ago in reply to Hillman Lin

Prodigy 140 points

Hi Hillman,

My idea is not to use a mux, but to connect directly to uC to the PHY.

Here's the block diagram of the MCU to PHY connection in my custom board

The evaluation board (LP-AM243x) uses a MUX instead:

The difference between the RGMII and CPSW isn't clear to me, so I'm wondering whether the CPSW connection is needed or not when using AM2434 with the industrial firmware provided by the industrial communication SDK.

Regards,

Andrea

+1 Hillman Lin over 1 year ago in reply to Andrea Favero

TI__Mastermind 25955 points

Hi Andrea,

I am not too familiar on the firmware on AM2434. From what our pass experience, we only see customer use RGMII interface with AM2434 but not CPSE interface. We still don't recommend to use MUX on the RGMII interface for some layout constraint.

Regards,

Hillman Lin

0 Andrea Favero over 1 year ago in reply to Hillman Lin

Prodigy 140 points

Hi Hillman Lin,

thank you for the support.

Regards.

Andrea

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DP83869HM: DP83869HM with AM2434