DP83822HF: can't link up

Lawrence Chih

Prodigy 100 points

Part Number: DP83822HF

Hi team,

I have some questions about the link-up.

In 100BASE-FX mode, the DP8382 pin 9,10,11,12 is need a capacitively coupled to the SFP?

I not sure has something wrong for the circuit, would you help me check the circuit?

fb-ktd700.pdf

over 3 years ago

0 Lawrence Chih over 3 years ago

Prodigy 100 points

Hi Team,

Could you help me, please

0 Justin Lazaruk over 3 years ago in reply to Lawrence Chih

TI__Expert 7040 points

Hi Lawrence,

The SGMII interface pins need to be capacitively coupled if the SFP does not provide coupling capacitors internally.

The register write to 0x0468 does not appear to be valid, please follow the Read Post Increment operation in section 8.4.2.7 of the DP83822 datasheet. Please share register data for 0x00, 0x01, 0x0A, and 0x10.

Can you please provide some clarification on the attached schematic, how are you indicating which components are DNP or Do Not Populate?

Regards,
Justin

0 Lawrence Chih over 3 years ago in reply to Justin Lazaruk

Prodigy 100 points

Hi Justin

Thank you for your reply.

I fixed the circuit to add the DNP callout and share the register data for 0x00, 0x01, 0x0A, and 0x10.

Please reference the attached.

Now I'm confirming with SFP engineer the coupling capacitors internal in the SFP If they did not provide in the SFP, which pins need to add capacitively coupled, is all the RMII connect pin?

best regards,

Lawrence

fb-ktd700_20200518.pdf

0 Lawrence Chih over 3 years ago in reply to Lawrence Chih

Prodigy 100 points

Hi Justin

I confirmed with the engineer the SFP provides coupling capacitors internally.

please help me check the register, thank you very much.

best regards,

Lawrence

0 Lawrence Chih over 3 years ago in reply to Lawrence Chih

Prodigy 100 points

Hi Justin

Thank for your help.

The problem is 0x00 register must disable Auto-Negotiation.

Thank you very much.

Best regards,

Lawrence

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DP83822HF: can't link up