DP83TG720S-Q1: The chip supports SGMII and RGMII. Which is active by default?

Laurence Cook

Part Number: DP83TG720S-Q1

Tool/software:

How do we change which mode it's in (we want SGMII)? So far we've made a little evaluation board to link two devices via Auto Ethernet, but we aren't seeing and comms over our SGMII path. Is there a proper programmers' guide for this part please?

over 1 year ago

0 Melissa Chang over 1 year ago

TI__Genius 14006 points

Hi Laurence,

By default, the DP83TG720S should be in SGMII mode if there are no pull up/pull down resistors on RXD[0:2].

You cannot switch between RGMII and SGMII through register writes. you can only switch between the states by changing the schematic (see section 7.5.1 Strap Configuration of the datasheet).

There is a software implementation guide here for the 720:

https://www.ti.com/lit/an/snla404/snla404.pdf?ts=1718212093467&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FDP83TG720S-Q1

To help you debug, can you provide a reading of registers 0x0-0x1F, and 0x45D when you try to communicate over the SGMII path?

Best regards,

Melissa

0 Laurence Cook over 1 year ago in reply to Melissa Chang

Prodigy 110 points

Thank you fir the information. We haven't programmed our control micro yet, so there will be a long delay before we can provide register content; however your reply is clear and vey helpful.

0 Melissa Chang over 1 year ago in reply to Laurence Cook

TI__Genius 14006 points

Hi Laurence,

Glad it was helpful, I will close this thread for now. Feel free to update once you have the registers.

Best regards,

Melissa

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DP83TG720S-Q1: The chip supports SGMII and RGMII. Which is active by default?