AM2434: PRU_ICSSG Ethernet with MII mode

Daisuke Maeda

Guru 19845 points

Part Number: AM2434
Other Parts Discussed in Thread: DP83848T, SYSCONFIG, DP83869HM, LP-AM243

For PRU_ICSSG Ethernet, does the MCU+ SDK and PRU firmware support MII mode instead of RGMII mode?

Best regards,

Daisuke

over 1 year ago

+1 Nilabh Anand over 1 year ago

TI__Mastermind 22254 points

Hi Daisuke San,

Yes, PRU_ICSSG Ethernet supports MII mode in the MCU+ SDK examples. Example support MII mode of ICSSG:

software-dl.ti.com/.../EXAMPLES_ENET_LAYER2_ICSSG.html

Can you answer few questions to help us better understand your use case:

1. Which example from sdk are you planning to use?

2. What is your use case?i.e how are intending to use PRU here?

Nilabh A.

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your reply.

Our customer wants to use the PRU_ICSSG Ethernet in MII mode with DP83848T which is a 10/100 Mbps PHY and may use the PRU_ICSSG Ethernet in multi MAC mode or multi-port switch mode.

Best regards,

Daisuke

+1 Nilabh Anand over 1 year ago in reply to Daisuke Maeda

TI__Mastermind 22254 points

Hi Daisuke San

Daisuke Maeda said:
Our customer wants to use the PRU_ICSSG Ethernet in MII mode with DP83848T which is a 10/100 Mbps PHY

Customer can use this PHY but they will need to port the driver for this. Is the use case industrial communication based? If so then, you can icss emac driver on top of PRU ICSSG.

You can refer https://software-dl.ti.com/mcu-plus-sdk/esd/AM243X/08_04_00_17/exports/docs/api_guide_am243x/NETWORKING.html#autotoc_md338

Nilabh A.

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your reply.

Our customer wants to use the PRU_ICSSG Ethernet as a normal Ethernet and does not use it for an industrial communication such as EtherNet/IP, PROFINET or EtherCAT.

Best regards,

Daisuke

+1 Nilabh Anand over 1 year ago in reply to Daisuke Maeda

TI__Mastermind 22254 points

Hi Daisuke San,

In that case, You can go ahead with enet examples. Please refer below examples:

https://software-dl.ti.com/mcu-plus-sdk/esd/AM243X/08_04_00_17/exports/docs/api_guide_am243x/EXAMPLES_ENET_LWIP_ICSSG.html

https://software-dl.ti.com/mcu-plus-sdk/esd/AM243X/08_04_00_17/exports/docs/api_guide_am243x/EXAMPLES_ENET_LAYER2_ICSSG.html

Nilabh A.

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your reply.

The "Enet Layer 2 ICSSG Example" supports MII mode, but needs to change the mode to MII from RGMII.

software-dl.ti.com/.../EXAMPLES_ENET_LAYER2_ICSSG.html
"Note: Enable the ENET_TEST_MII_MODE macro in test application and change the mode to MII from RGMII in SysConfig and rebuid the application to test the ICSSG ports in MII mode."

Does the "Enet Lwip ICSSG Example" support MII mode?

Best regards,

Daisuke

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

I have an additional question.

PRU_ICSSG has rxlink signals in MII mode as shown below.

pr0_mii0_rxlink
pr0_mii1_rxlink
pr1_mii0_rxlink
pr1_mii1_rxlink

Is the rxlink signal supported for a normal Ethernet?

If so, to which pin on a PHY (e.g. DP83848T) should the rxlink signal be connected?

The rxlink signal seems to be used only for an industrial communication in the SDK.

Best regards,

Daisuke

+1 Nilabh Anand over 1 year ago in reply to Daisuke Maeda

TI__Mastermind 22254 points

Hi Daisuke San,

Daisuke Maeda said:
Does the "Enet Lwip ICSSG Example" support MII mode

Yes It supports MII mode. But it will be required to take the changes from Enet Layer 2 ICSSG Example code for MII Mode.

Daisuke Maeda said:
Is the rxlink signal supported for a normal Ethernet?

Can you please elaborate what is the use case here for these pins?

Daisuke Maeda said:
If so, to which pin on a PHY (e.g. DP83848T) should the rxlink signal be connected?

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/454639/connection-of-am3357-pru-rxlink-singals

Please refer this e2e to understand use of this pins.

Daisuke Maeda said:
The rxlink signal seems to be used only for an industrial communication in the SDK.

Some specific protocols require explicit use of this pin. This can be left floating in case of normal ethernet.

Nilabh A.

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your reply.

It seems that the rxlink signal is typically used to detect the fast link down in an industrial communication.

On the TMDS243GPEVM and LP-AM243, each AM243x pin corresponding to the rxlink signal is connected to the LED_0 pin of the DP83869HM.

Does the PRU firmware for normal Ethernet support the rxlink signal?

If so, which polarity of the rxlink signal, active high or active low?

Best regards,

Daisuke

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your support.

Daisuke Maeda said:
Does the PRU firmware for normal Ethernet support the rxlink signal?

If so, which polarity of the rxlink signal, active high or active low?

Please give me an answer as soon as possible. Your prompt reply would be appreciated.

Best regards,

Daisuke

0 Nilabh Anand over 1 year ago in reply to Daisuke Maeda

TI__Mastermind 22254 points

Hi Daisuke San,

Apologies for delay in response due to vacations.

Please let me get back on it once I get input from internal team.

Nilabh A.

+1 Nilabh Anand over 1 year ago in reply to Nilabh Anand

TI__Mastermind 22254 points

Hi Daisuke San,

ICSSG PRU firmware does not use Fast link detection. This is not a firmware feature and more like how link is detected.

Daisuke Maeda said:
Does the PRU firmware for normal Ethernet support the rxlink signal?

If so, which polarity of the rxlink signal, active high or active low?

Firmware is not responsible for link detection, enet driver has to to indicate whether link is up or down(synchronous ioctl). For polarity you can follow existing schematics of am243 evm.

Nilabh A.

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your reply.

I understand that the rxlink signal is supported by FW for industrial communication such as EtherCAT but not by FW for normal Ethernet, is that correct?

The rxlink signal to PRU_ICSSG seems to be used in examples for industrial communication such as EtherCAT.

If fast link detection is needed for normal Ethernet, is normal GPIO used instead of the rxlink signal to PRU_ICSSG?

Best regards,

Daisuke

+1 Nilabh Anand over 1 year ago in reply to Daisuke Maeda

TI__Mastermind 22254 points

Hi Daisuke San,

Daisuke Maeda said:
I understand that the rxlink signal is supported by FW for industrial communication such as EtherCAT but not by FW for normal Ethernet, is that correct?

Yes that is correct.

Daisuke Maeda said:
If fast link detection is needed for normal Ethernet, is normal GPIO used instead of the rxlink signal to PRU_ICSSG?

Yes normal GPIO can be used.

Nilabh A.

0 Daisuke Maeda over 1 year ago in reply to Nilabh Anand

Guru 19845 points

Hi Nilabh A-san,

Thank you for your reply.

Best regards,

Daisuke

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AM2434: PRU_ICSSG Ethernet with MII mode