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Visitor idanko
Visitor
12,318 Views
Registered: ‎09-10-2014

IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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Hi,

 

I have created an IBERT 7-Series GTX IP core for the ZC706 development board. Essentially the same configuration as in xtp243 except I only utilize GTX_Quad 111 and use an external reference clock supplied to MGTREFCLK1_111 via its SMA connectors. I created and tested the design both in ISE/ChipScope 14.7 (using v2.02.a of the core) and in Vivado 2014.2 (with v3.0 of the core).

 

Three of the GTXs in the Quad have their TX/RX ports connected:

GTX1_111 (GTX_X0Y9) with external SMA cables,

GTX2_111 (GTX_X0Y10) with an optical loopback module (not the same shown in xtp243 document) inserted into the SPF+ transceiever on the board,

GTX3_111 (GTX_X0Y11) connected internally on the board.

 

In Vivado 2014.2, GTX_X0Y10 with the optical SFP+ connector and the optical loop back module inserted has no LINK (see the first screen shot) while the same GTX is working and happy in ISE/ChipScope 14.7 (see second screen shot). The tests were done one after the other without touching the board or the connectors. Any suggestion why the Vivado 2014.2 design does not work for this particular transceiver but seems to work in ISE?

 

IBERT_ZC706_Vivado2014-2.png
IBERT_ZC706_ISE14-7.png
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Visitor vsavinov
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Registered: ‎09-02-2014

PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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Well, venkata and Boris, thank you for suggesting to us to check all the parameters and stuff - I am happy to report I solved this "problem".

 

Here is what I "discovered" (this will be embarrassing!):

 

Eval board ZC706 has jumper J17. 

 

According to UG954:

 

p.47:  "SFP_TX_DISABLE,   Jumper 17,    Off=SFP disabled, On=SFP enabled" 

- according to this it looks like jumper needs to be present to enable SPF

(there is no jumper there when the board is shipped). 

 

p.96: "J17   SPF+ P2 SFP_TX_DISABLE_TRANS Header,   Default position: OPEN,  Selects: SFP+ P2 TX enabled"

 

Everything seems to be kosher BUT here is what confused us:

 

ISE 14.7 reports this transceiver as working (link established) when an optical loopback is present REGARDLESS of a jumper being or not being present in J17! In other words, ISE does not care about J17!  However, Vivado DOES. Now, in Vivado, everything is working beautifully when the jumper is installed, removing the jumper takes us back to "No link" condition. Problem solved. 

 

Also, just in case, when using IBERT in ISE (i.e. ChipScope in ISE), removing optical loopback gives us "No link" condition (this proves that we are actually using SFP+/fiber even when using ISE 14.7). Same in Vivado. Patting myself on my back now. 

 

For some time already I suspected that some "broken logic" (besides my inability to read the manual :)) is present but ... anyway, I will finally be able to sleep well tonight!   

 

In one sentence:  Vivado cares about jumper J17, it must be installed in order for SFP+ to be ON for Vivado IBERT v3.0, however, it does not matter for ChipScope/ISE IBERT v2.*. 

12 Replies
Moderator
Moderator
12,216 Views
Registered: ‎02-16-2010

Re: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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Do you see link up in Near end loopback modes? What is the status of RESETDONE signals when the link fails?
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Xilinx Employee
Xilinx Employee
12,207 Views
Registered: ‎08-07-2007

Re: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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hi,

 

1, first off, did you use 800mV or 900mV RX termination in Vivado. By default it's GND if i remember it correctly.

Right click on the ' name  tx rx status bits ...' row then you will see it.

 

2, please try TX reset and RX reset and see if it works

 

3, please make sure the settings are the same.

i see the following differences.

PRBS7 - PRBS31

TX amplitude

 

Thanks,

Boris

 

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Visitor vsavinov
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Registered: ‎09-02-2014

Re: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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My colleague (idanko) is gone until next week, so I continue working on this problem while he is traveling. Here is some new information:  

 

I discovered that RXUSERCLK for the offending transceiver is reporting a frequency different from TXUSERCLK (please see below).  

 

Experts, could you please comment on this?  

ibert_problems_1.gif
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Visitor vsavinov
Visitor
12,164 Views
Registered: ‎09-02-2014

Re: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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>> Do you see link up in Near end loopback modes? What is the status of RESETDONE signals when the link fails?

 

hi venkata, 

 

yes, the offending link (link 22, MGT_X0Y10) is up when in near-end loopback mode - please see the snapshots below. Note also that, when operating the transceivers in near-end loopback mode all the user clocks run at the same correct frequency.

 

thanks!

 

 

ibert_problems_2.gif
ibert_problems_3.gif
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Visitor vsavinov
Visitor
12,163 Views
Registered: ‎09-02-2014

Re: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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and here is info conerning RESETDONE:

 

the status of RXRESETDONE and TXRESETDONE for the offending transceiver are 1 and 1 regardless of link being up (in near-end loopback, snapshot#3 below) or down (in no loopback, snapshot#4)

ibert_resetdone_link_is_up.gif
ibert_resetdone_link_is_down.gif
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Visitor vsavinov
Visitor
12,155 Views
Registered: ‎09-02-2014

Re: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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Hi Boris, 

 

>>1, first off, did you use 800mV or 900mV RX termination in Vivado. By default it's GND if i remember it correctly. Right click on the ' name  tx rx status bits ...' row then you will see it.

 

900mV (it was set to this by default) - please see the snapshot

 

 

>> 2, please try TX reset and RX reset and see if it works

 

I tried this many times - also, I tried to change various parameters of IBERT IP core and then rerun the synthesis and implementation many times - nothing helps. I suspect that the issue is with this USERCLK - but I do not understand why it is different on the offending transceiver. I also tried several different SFP+ modules and several different optical loopbacks. Always works in ISE 14.7, never works in Vivado 2014.2 on SFP+ on ZC706. 

 

>> 3, please make sure the settings are the same. i see the following differences. PRBS7 - PRBS31 TX amplitude

 

tried this also - please see the snapshot below 

 

Thank you very much for helping us understand our problem, it has been driving my colleague and me crazy for the past two weeks. 

v

ibert_problems_4.gif
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Visitor vsavinov
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19,852 Views
Registered: ‎09-02-2014

PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

Jump to solution

Well, venkata and Boris, thank you for suggesting to us to check all the parameters and stuff - I am happy to report I solved this "problem".

 

Here is what I "discovered" (this will be embarrassing!):

 

Eval board ZC706 has jumper J17. 

 

According to UG954:

 

p.47:  "SFP_TX_DISABLE,   Jumper 17,    Off=SFP disabled, On=SFP enabled" 

- according to this it looks like jumper needs to be present to enable SPF

(there is no jumper there when the board is shipped). 

 

p.96: "J17   SPF+ P2 SFP_TX_DISABLE_TRANS Header,   Default position: OPEN,  Selects: SFP+ P2 TX enabled"

 

Everything seems to be kosher BUT here is what confused us:

 

ISE 14.7 reports this transceiver as working (link established) when an optical loopback is present REGARDLESS of a jumper being or not being present in J17! In other words, ISE does not care about J17!  However, Vivado DOES. Now, in Vivado, everything is working beautifully when the jumper is installed, removing the jumper takes us back to "No link" condition. Problem solved. 

 

Also, just in case, when using IBERT in ISE (i.e. ChipScope in ISE), removing optical loopback gives us "No link" condition (this proves that we are actually using SFP+/fiber even when using ISE 14.7). Same in Vivado. Patting myself on my back now. 

 

For some time already I suspected that some "broken logic" (besides my inability to read the manual :)) is present but ... anyway, I will finally be able to sleep well tonight!   

 

In one sentence:  Vivado cares about jumper J17, it must be installed in order for SFP+ to be ON for Vivado IBERT v3.0, however, it does not matter for ChipScope/ISE IBERT v2.*. 

Newbie norm
Newbie
11,690 Views
Registered: ‎11-17-2014

Re: PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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Hi,  I'm a newbie with SFP -- we have a design working in-house connecting two ZC706 boards via the on-board SMA link using Aurora, and would like to migrate to using SFP+ over fiber.

 

Is there a Xilinx reference design that shows how to start with this, perhaps using a Xilinx SFP core, or if not, is there a 3rd-party core available that might also provide a reference design to show us how?

 

Thanks,  Norm

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Xilinx Employee
Xilinx Employee
11,683 Views
Registered: ‎01-03-2008

Re: PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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SFP/SFP+ are simply a translation between electrical signals to optical signals.  The same design that you have working for the SMA+coax should work with the electrical modules. 

------Have you tried typing your question into Google? If not you should before posting.
Too many results? Try adding site:www.xilinx.com
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Newbie norm
Newbie
8,476 Views
Registered: ‎11-17-2014

Re: PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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This is good news, if I understand it.  But we are current using Aurora protocol at 6.25Gbps as a loopback between the two on-board GTX links on J32-J35 using SMA cables.  Surely it cannot be as simple as changing those links to the ones feeding the SFP+ connector and using the loopback SFP+ connector from Molex?  And if so, what limits the maximum data rate for the SFP+ connection in this case?

 

Thanks, Norm

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Xilinx Employee
Xilinx Employee
8,465 Views
Registered: ‎01-03-2008

Re: PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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>   Surely it cannot be as simple as changing those links to the ones feeding the SFP+ connector

 

It is, with one small addition that the SFP module disable pin is not asserted.\\

 

> And if so, what limits the maximum data rate for the SFP+ connection in this case?

 

That is defined by the data sheet of the module that is used.

------Have you tried typing your question into Google? If not you should before posting.
Too many results? Try adding site:www.xilinx.com
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Newbie norm
Newbie
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Registered: ‎11-17-2014

Re: PROBLEM SOLVED: IBERT on ZC706 with SFP+ transceiver works in ISE DS 14.7 but not in Vivado 2014.2

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Thanks.  I'll try it out.

 

Norm

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