DS25CP102 issue

Madhuri Akkenepalli

Expert 1215 points

Other Parts Discussed in Thread: DS25CP102

My customer has a new design using TI DS25CP102. The input IN_0 is PCIE gen 1. IN_1 is one of the XAUI lane.

The initial testing of the signal P4080_PST is low. However, the input IN_0P and output OUT_1P are different.

Q1: Does this chip support PCIE signaling?

Q2: Please review the connections and do you see any mistake?

Q3: What is the possible reason why OUT_1P is differnet than IN_0P?

please advise.

over 10 years ago

0 Lee Sledjeski over 10 years ago

TI__Mastermind 43795 points

Hi MadhuriThe DS25CP102 is not designed to be PCIe compatible.
I do not see a schematic to review the connections or understand the input -> output configuration of the crosspoint.
Regards,Lee

0 Madhuri Akkenepalli over 10 years ago in reply to Lee Sledjeski

Expert 1215 points

Thank you Lee.

Please advise on how to send the schematic to you. I am unable to attach it here in the reply post.

regards
Madhuri

0 Lee Sledjeski over 10 years ago in reply to Madhuri Akkenepalli

TI__Mastermind 43795 points

Use lee.sledjeski@ti.com

0 LeonardEllis over 10 years ago in reply to Madhuri Akkenepalli

TI__Guru 71526 points

Use the RICH FORMATTING option (lower right corner) to enable attachments.

You will see a paper clip icon for attachments, and an INSERT icon to add pictures, etc inside the posting. And you can change fonts and colors as well!!

0 Madhuri Akkenepalli over 10 years ago in reply to Madhuri Akkenepalli

Expert 1215 points

Hi Lee,

Please find the schematic attached here.

Thank you.

TI_2x2_DS25CP102.pdf

0 Madhuri Akkenepalli over 10 years ago in reply to LeonardEllis

Expert 1215 points

Thanks!

0 Lee Sledjeski over 10 years ago

TI__Mastermind 43795 points

Hi Madhuri,

I do not see anything wrong in the schematic diagram. Is it possible to probe the differential waveform at IN0p - IN0n and compare it with the waveform at OUT1p - OUT1n?

Regards,

Lee

0 Madhuri Akkenepalli over 10 years ago in reply to Lee Sledjeski

Expert 1215 points

Hi Lee, please find the scope shots of the inputs and outputs.

Channel 1 (yellow) is input pin 1, Channel 2 (blue) is output at pin 10.

Channel 3 (purple) is output at pin 12. It looks like input 1 is sending idle pulse periodically.

Out_1P (pin 10) is high, because EN1 is high, but it doesn’t track In_0P

Out_0P (pin 12) is 0 because EN0 (P4080_PST) is 0

Please review it and advise on your feedback.

Thank you.
regards

Madhuri

0 Lee Sledjeski over 10 years ago in reply to Madhuri Akkenepalli

TI__Mastermind 43795 points

Madhuri,

If you look at the input on pin 2 at the same time as pin 1 do you see the same signal?

If yes, then this signal is part of the PCIe receiver detection process. In order for the DS25CP102 to output this signal, it would need to be present as a "differential" signal. If pin1 and pin2 both have the same signal present, then the difference = 0 so the DS25CP102 output will not track the input signal.

The DS25CP102 is not PCIe compliant. It is not capable to work as a PCIe 2x2 crosspoint.

Best Regards,

Lee

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DS25CP102 issue