RM46L852: About Ethernet Interface

Hi Chunho,

No need to do any schematic changes to operate HDK in MII interface, by default it will operate in MII interface only.

And it requires couple of changes to operate in RMII interface, please verify below thread. 

(+) TMS570LC4357: MII and RMII design with LWIP - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

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Thanks & regards,
Jagadish.

Dear

We have RM46_HDK_SCHEMATICS_REVE schematic in your reference design.

We want to config with RMII interface between rm46l852 and DP83640 in your reference shematic.

what needs to change for RMII in your schematic?

Hi Chunho,

Do below modifications for RMII interface

1. Populate R193 resistor (2.2kohms) to pull RX_DV up

2. Replace Y3 with a 50-MHz oscillator 

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Thanks & Regards,
Jagadish.

Is it possible to operate with the RMII interface by leaving all the circuits in RM46_HDK_SCHEMATICS_REVE and

changing only the two things mentioned above in RM46_HDK_SCHEMATICS_REVE?

Hi Chunho,

chunho cho said:

Is it possible to operate with the RMII interface by leaving all the circuits in RM46_HDK_SCHEMATICS_REVE and

changing only the two things mentioned above in RM46_HDK_SCHEMATICS_REVE?

Yes, it is possible, only above mentioned two modifications are fine to operate in RMII mode.

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Thanks & regards,

Jagadish.

I want to compose a circuit with RMII interface.
What signals should be connected between the RM46L852 and DP83640 in RM46_HDK_SCHEMATICS_REVE?
And does the DP83640 operate in master mode or slave mode?

Hi Chunho,

Can you please refer DP83640 phyter datasheet to understand more details about the phyter

DP83640 Precision PHYTER - IEEE 1588 Precision Time Protocol Transceiver datasheet (Rev. F)

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Thanks & Regards,
Jagadish.

jagadish gundavarapu said:

Below is the RM46L852 and DP83640 RMII interface schematic. Please check if there are any parts that need to be corrected.

Hi Chunho,

You are missing to connect "RMII_MHZ_50_CLK"

In HDK it is connected from OSC to K19(RMII_REFCLK) pin of the controller.

Except that remaining connections are fine.

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Thanks & Regards,
Jagadish.

Thank you for quick response. Please check if the RMII_REFCLK circuit connection is correct.