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Explorer
Explorer
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Registered: ‎10-12-2018

Aurora channel down. IBERT clean II

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Hi,

I have a system with two FPGAs (a 7series Zynq, and a 7series Virtex) which are connected via Aurora (5GHz simplex single lane 64/66B). The link cannot came up, however, when, I inspected the link using IBERT, and the eye is clean. Here is a similar question, but its solution is to reduce the speed...

Here is result of the IBERT eye-scan:

ibert5GBP.PNG


If I understand well the behavior of the eye-scaner from the UG476 Transceiver Guide, (RX Margin section) the transmitter and the receiver don't need to use the same bit pattern to create the eye-scan. Am I right? (I have done some experiences which verified this. Note, that IBERT will say link-down, but the eye will valid.)

So I replaced the image of the transmitter FPGA with the Aurora image. Then I made eye scan again: (The transmitter is Aurora the receiver is IBERT)

04afterPS7_post_conf.PNG

This is a simplex Aurora, so after reset, so it sends data after reset. So I think this is a valid eye-diagram. Am I right? (I mean valid = the measurement is valid and the image shows the real state of the pin.) If yes why this eye isn't clean?

Q:

  1. Is the Aurora -> IBERT eye-scan valid? (from the measurement perspective)
  2. What is the difference between the IBERT and the Aurora?
  3. How can I copy the transceiver settings from IBERT to Aurora?

I use:

  • Zynq (xc7z030sbg485-2) at transmitter (with custom board)
  • 7 series Virtex (VC707 xc7z030sbg485-2)
  • Aurora 64/66B simplex single lane 5Gbps
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Explorer
Explorer
477 Views
Registered: ‎10-12-2018

Re: Aurora channel down. IBERT clean II

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Hi @csattar 

1. Is the Aurora -> IBERT eye-scan valid? (from the measurement perspective)

"NOT vaild eye -scan since IBERT use it own PRBS and you need use in-system IBERT tool"

I think that this scan is still valid. I have tested with IBERT -> IBERT, but with different RX and TX pattern, and the eye was as clean as when I use the same pattern. (I have tried with different configs: PRBS7->PRBS31 ; FastClock -> PRBSxx ; ; PRBSxx-> SlowClock etc. Note, that if the RX and TX pattern is different the Link status shows No Link, but the eye is clean)
@csattar In your point of view test above should be failed, however they passed.

2. What is the difference between the IBERT and the Aurora?

As I wrote several times I have 7series device not UScale. @csattar Can I ask you to read my question before answer it?

To ask this question more precisely: What differences are between the IBERT and the Aurora default PMA settings?

3. How can I copy the transceiver settings from IBERT to Aurora?

"can i know the reason"

The goal is a working Aurora channel. Now, the Aurora (If both sides uses image containing Aurora not IBERT) shows channel down. If I connect the RX and TX with standard coax cables, the link is up and running, but when I use our custom board, the link is down. So the root of the problem should be in the physical layer. This is why I want to copy the PMA settings from IBERT (which shows open eye) to Aurora (which showh link down)

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Moderator
Moderator
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Registered: ‎05-02-2017

Re: Aurora channel down. IBERT clean II

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hi @betontalpfa ,

 

  1. Is the Aurora -> IBERT eye-scan valid? (from the measurement perspective).

  Ans : NOT vaild eye -scan since IBERT use it own PRBS and you need use in-system IBERT tool

  1. What is the difference between the IBERT and the Aurora?

Ans : IBERT :The IBERT for UltraScale GT Transceivers core provides a broad-based Physical MediumAttachment (PMA) evaluation and demonstration platform for UltraScale architecture GT
transceivers. Parameterizable to use different GT transceivers and clocking topologies, the IBERT for UltraScale GT Transceivers core can also be customized to use different line rates, reference clock rates, and logic widths. Data pattern generators and checkers are included for each GT transceiver desired, giving several different pseudo-random binary sequence (PRBS) and clock patterns to be sent over the channels.
where as Aurora is IP core used to bulid a serial link using the GT

3. How can I copy the transceiver settings from IBERT to Aurora?

ANS: can i know the reason

Regards
Chandra sekhar
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Explorer
Explorer
478 Views
Registered: ‎10-12-2018

Re: Aurora channel down. IBERT clean II

Jump to solution

Hi @csattar 

1. Is the Aurora -> IBERT eye-scan valid? (from the measurement perspective)

"NOT vaild eye -scan since IBERT use it own PRBS and you need use in-system IBERT tool"

I think that this scan is still valid. I have tested with IBERT -> IBERT, but with different RX and TX pattern, and the eye was as clean as when I use the same pattern. (I have tried with different configs: PRBS7->PRBS31 ; FastClock -> PRBSxx ; ; PRBSxx-> SlowClock etc. Note, that if the RX and TX pattern is different the Link status shows No Link, but the eye is clean)
@csattar In your point of view test above should be failed, however they passed.

2. What is the difference between the IBERT and the Aurora?

As I wrote several times I have 7series device not UScale. @csattar Can I ask you to read my question before answer it?

To ask this question more precisely: What differences are between the IBERT and the Aurora default PMA settings?

3. How can I copy the transceiver settings from IBERT to Aurora?

"can i know the reason"

The goal is a working Aurora channel. Now, the Aurora (If both sides uses image containing Aurora not IBERT) shows channel down. If I connect the RX and TX with standard coax cables, the link is up and running, but when I use our custom board, the link is down. So the root of the problem should be in the physical layer. This is why I want to copy the PMA settings from IBERT (which shows open eye) to Aurora (which showh link down)

View solution in original post

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Explorer
Explorer
446 Views
Registered: ‎10-12-2018

Re: Aurora channel down. IBERT clean II

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I have proofed my theorem. And Aurora -> IBERT eye-scan is valid.

I have reduced the line-rate and in this case the Aurora -> IBERT eye is clean and open too. (Note, that IBERT still reports No Link in Serial I/O Links tab, but this is normal.)

Here is an eye of Aurira -> IBERT (1Gbps) (Open Area: 19840)

31Aur2Ibert_1G_fine.PNG

Here is the eye of the same link using IBERT -> IBERT (1Gbps) (Open Area: 29112)

33Ibert2Ibert_1G_fine.PNG

Note, that there is a difference (in cleanliness) between the two scan. The IBERT->IBERT is more open (*1.5).

Now I'm interested in how to apply these IBERT settings to Aurora?

 

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