DP83TC813R-Q1: TDR Testing Incorrect Values:

ahmed abdelazim

Tool/software:

Dear TI support team,

When Attempting to conduct TDR Testing with both ethernet wires not connected (both wires open circuit) The TDR_TC1 Register (Address = 310h) [Reset = 0000h]
The Data Received fluctuates between (half wire open detected / half wire open not detected) although we are conducting the same TDR Test Procedure each time

we have conducted a lot of debugging and we read each register right after writing it and the result can be shown in screen shot below

Also can you tell me what is the expected behavior in the sequence when attempting to conduct the TDR Test Procedure with good cable connected?

7 months ago

0 Gregory Kobyakov 7 months ago

TI__Genius 10170 points

Hi Ahmed,

I will check with the team on this and get back to you tomorrow.

Best regards,

Greg

0 Gregory Kobyakov 7 months ago

TI__Genius 10170 points

Hi Ahmed,

The half wire bit of the device has been previously found to not function as intended, and we are working to update the data sheet to reflect this.

Best regards,

Greg

0 ahmed abdelazim 7 months ago in reply to Gregory Kobyakov

Prodigy 181 points

Hello Gregory,

i just need to know this service will not be any more supported ,or what is the update will be done in the data sheet .

0 Gregory Kobyakov 7 months ago in reply to ahmed abdelazim

TI__Genius 10170 points

Hi Ahmed,

The half-open detect bit was found to be unreliable, so the bit has been made reserved. This is reflected in the changes from Revision C to Revision D of Application Note SNLA389F. The TDR testing procedure in Section 7.1 of this document has also been updated.

Best regards,

Greg

0 ahmed abdelazim 7 months ago in reply to Gregory Kobyakov

Prodigy 181 points

Hello Gregory,

Can you please provide us with the updated document ,

and also can you please tell us the applicability to correct this feature to make it work correctly.

0 Gregory Kobyakov 7 months ago in reply to ahmed abdelazim

TI__Genius 10170 points

Hi Ahmed,

I have attached the Application Note with the most updated TDR testing procedure below. Please follow the TDR Run Procedure in the document, as it no longer includes any references to the unreliable detect bit.

Best regards,

Greg

snla389f.pdf

0 Ahmed ATEF-IBRAHIM 7 months ago

Prodigy 10 points

Hi Gregory,

Please can you tell us explicitly if it's HW limitation to support it, or it's SW related and can be corrected

Thanks in advance

0 Gregory Kobyakov 7 months ago in reply to Ahmed ATEF-IBRAHIM

TI__Genius 10170 points

Hi Ahmed,

The issue is a hardware limitation, as the half-detect bit does not reliably indicate half-open and full-open detection. Therefore the team decided to defeature the bit in the latest technical documents for the device.

Best regards.

Greg

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DP83TC813R-Q1: TDR Testing Incorrect Values: