[FAQ] AM2434: Is TI EtherCAT solution in the Industrial Communications SDK compatible with RGMI ?

Daisuke Maeda said:

RGMII is also used in the case of EtherCAT.

This is not correct, ICSSG has pinmux options at SoC level which allows it to switch between RGMII and MII interface based on HW initialization together with PHY like DP83869 which supports both the interfaces. AM243x INDUSTRIAL COMMUNICATIONS SDK: EtherCAT SubDevice FWHAL

Hi,

For EtherCAT operation, the PRU-ICSSG must operate in MII mode. This is a fundamental requirement of the EtherCAT implementation on AM243x, and RGMII cannot be used. The PHY must be connected to PRU-ICSSG using MII interface for EtherCAT operation and this applies to both the LP-AM243 LaunchPad and any custom board designs using AM243x. This is a hardware/firmware architectural requirement specific to EtherCAT operation, regardless of the board design you're using with AM243x.

Regards,
Aaron

Hi,

Daisuke Maeda said:

Is it recommended to use DP83869HM (in MII mode) for "EtherCAT (100Mbit/s)"?

• We'll let the interface team comment on this. They will provide the recommended PHY for EtherCAT communication.

Daisuke Maeda said:

The DP83869HM is listed for "EtherCAT G (1,000 Mbit/s)" but NOT for "EtherCAT (100 Mbit/s)" in Beckhoff's PHY selection guide.

• Since our hardware supports Gigabit communication, DP83869HM is used in the AM243x EVMs and LPs. While the DP83869HM is also suitable, taking into consideration the cost factor and it being typically oversized (being a Gigabit PHY) and for standard EtherCAT applications where 100Mbps is sufficient, DP83869HM won't be the most optimal solution for 100M EtherCAT.

Regards,
Aaron