DRA821U-Q1: How to disable SERDES_REFLCK internal termination ?

Max Chen1

Intellectual 715 points

Part Number: DRA821U-Q1
Other Parts Discussed in Thread: DRA821

Tool/software:

SERDES_REFCLK has internal termination 40 - 62.5ohm, how can I disable it?

4 months ago

0 Robert Eschler 4 months ago

TI__Guru 52685 points

I'm looping in additional resources. Can you provide additional info on your issue with SERDES_REFCLK and why you need changes to termination?

0 ShreyasRao 4 months ago in reply to Robert Eschler

TI__Guru 62350 points

Hi Max,

You should be able to disable the ref clk using the SERDES_RST register bit 27: REFCLK_TERM_DIS.

0 Max Chen1 4 months ago in reply to ShreyasRao

Intellectual 715 points

which document shows that ?

I cannot find it from reference manual

0 ShreyasRao 4 months ago in reply to Max Chen1

TI__Guru 62350 points

Do you have the document with all the register information available with you?

0 ShreyasRao 4 months ago in reply to ShreyasRao

TI__Guru 62350 points

You could refer to the TRM of the J721s2 in the section of SERDES_10G below: The offset and the base address will need to be adjusted based on the DRA821 setting.

https://www.ti.com/product/TDA4VE-Q1

I looked into the DRA821 datasheet and the SERDES registers are still to be populated. I will reach out internally to get this populated.

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DRA821U-Q1: How to disable SERDES_REFLCK internal termination ?