DS250DF810: There is link up problem if we set two Retimer as 40G and 100G separately.

Eason Hsieh

Prodigy 10 points

Part Number: DS250DF810

Hi TI,

We use two DS250DF810 for 2 port QSFP28 100G and 40G.

100G and 40G both are successful link up with transceiver.

But there is link up problem if we set two Retimer as 40G and 100G separately.

Could we set two Retimer as 40G and 100G separately?

Are there any setting or register we should check?

Two Retimer CLK source are connected as daisy-chained,

Thank you!

Eason

over 3 years ago

0 Drew Miller1 over 3 years ago

TI__Mastermind 36933 points

Hi Eason,

Can you clarify the difference between the retimer setup under successful linkup conditions compared to when you configure the retimers separately? This is not clear to me from your description of the problem.

Eason Hsieh said:
Could we set two Retimer as 40G and 100G separately?

Yes, you can configure two retimers separately. I would recommend configuring them separately for a 40G and 100G system since they require a different set of register writes.

Eason Hsieh said:
Are there any setting or register we should check?

Yes, you should ensure that register 0x2F is set appropriately for your data rate. This can be found in Table 7-6 of the programming guide. After configuring the data rate, it is important to complete a CDR reset procedure. This can be done via the following register writes.

Register Address	Write Value	Write Mask	Description
0x0A	0x0C	0x0C	Assert CDR reset
0x0A	0x00	0x0C	Release CDR reset

Thanks,

Drew

0 Eason Hsieh over 3 years ago in reply to Drew Miller1

Prodigy 10 points

Hi Drew,

After internal discussion.
We will configure them for a 40G and 100G system separately that will be easier for SW design.

Thanks for suggestion!

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DS250DF810: There is link up problem if we set two Retimer as 40G and 100G separately.