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Using 10Gb/Sec SFP board with Genesys2

sagiFTW

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sagiFTW Newbie

sagiFTW

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Hello,

I'm a student and I'm designing a project which transmits data from a dual ADC board (ADS4249) over optical fiber and then reconstruct it to Analog signal using DAC3283 DAC evaluation board by TI. 
Both of those evaluation boards got a FMC to DAC/ADC adapter:
http://www.ti.com/tool/FMC-DAC-ADAPTER
http://www.ti.com/tool/fmc-adc-adapter

TI claims that it is for Xilinx FNC connector. I wonder if anyone tried to connect those boards to Digilent Genesys 2 evaluation board FMC connector?
Are they pin compatible? Is there any source code? TI provide source code for Altera FPGAs only.

The other question is about interfacing to SFP+ optics:
I would like to interface a SFP+ cage to every board. There are no dedicated connectors and I cannot use the FMC connector because the ADC or DAC would be connected to it.

There are many SFP+ boards with SMA connectors for the 10.3 GHz signals and simple 2 row connectors for the I2C interface.
Is there any place in the Digilent Genesys 2 board to connect 2 cables for the 10.3 signals? 
Please consider the fact that the FMC connector would be probably occupied by the ADC or DAC card and I cannot use FMC to SFP boards..

If those lines are already connected to other function on this board - like USB or VGA etc. then I don't mind disconnecting them.

I see that the FPGA has "2FF" speed grade so it has transceivers which support 10.3GHz signals.

As for the I2C signals needed for programming the SFP - Can I use standard GPIO lines? From where can I connect them?

I would appreciate your detailed response.

SagiFTW

 

 

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elodg Prolific Poster

elodg

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Hello,

I'm a student and I'm designing a project which transmits data from a dual ADC board (ADS4249) over optical fiber and then reconstruct it to Analog signal using DAC3283 DAC evaluation board by TI. 
Both of those evaluation boards got a FMC to DAC/ADC adapter:
http://www.ti.com/tool/FMC-DAC-ADAPTER
http://www.ti.com/tool/fmc-adc-adapter

TI claims that it is for Xilinx FNC connector. I wonder if anyone tried to connect those boards to Digilent Genesys 2 evaluation board FMC connector?
Are they pin compatible? Is there any source code? TI provide source code for Altera FPGAs only.

For sure they are not pin compatible, but adhere to the common VITA.57 spec. You will need to change the XDC location constraints, but otherwise the same features are available in the G2 FMC connector as on the Xilinx ones. If anything the Digilent board has more pins wired, the G2 FMC connector is a fully-bonded High Pin-Count connector.

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The other question is about interfacing to SFP+ optics:
I would like to interface a SFP+ cage to every board. There are no dedicated connectors and I cannot use the FMC connector because the ADC or DAC would be connected to it.

There are many SFP+ boards with SMA connectors for the 10.3 GHz signals and simple 2 row connectors for the I2C interface.
Is there any place in the Digilent Genesys 2 board to connect 2 cables for the 10.3 signals? 
Please consider the fact that the FMC connector would be probably occupied by the ADC or DAC card and I cannot use FMC to SFP boards..

The only place where you can wire into the GTX transceivers are shown on pg 14 of the schematic: DisplayPort and FMC DPx pins. DisplayPort connectors have not been tested with >5.4 Gbps, nor they are certified for those rates. This leaves you with the option of designing an FMC mezzanine card for yourself that have the ADC, DAC and SFP+ cage on it.

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As for the I2C signals needed for programming the SFP - Can I use standard GPIO lines? From where can I connect them?

For I2C you may use any of the User I/O pins of the FMC: LAx, HAx... Or even Pmods. Pay attention to I/O voltages.

 

 

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zygot Prolific Poster

zygot

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@sagiFTW

I have used the FMC connector on the Genesys2 and Nexys Video board with a variety of FMC mezzanine cards that various vendors offer to evaluate components like ADCs and DACs. I can't answer your question directly but can offer you some guidance based on my experience ( I'm also an EE with over 35 year of experience ).

  • You will have to get the schematics for the Gensys2 and whatever FMC mezzanine card you want to use and carefully work out every signal to verify that the signalling standards are compatible. This means checking the IO bank voltages available and if using transceivers that the clocking is compatible.
  • Be careful of vendor adapter cards with an FM connector. I've used a lot of the successfully but not every signal that you want to use is likely to make it all the way through the adapter. This is another level of signal tracing to do.
  • You need to get gerbers for the FMC board to see if there are mechanical issues. I've used an ADC eval board from Ti that had capture posts that need to be cut off ( I was still able to use it but there are mechanical stability issues ). A lot of vendors make some sort of mention of VITA-57 without claiming compatibility ( particularly mechanically ) though some vendors do state that their mezzanine cards are not VITA-57 compliant.
  • I've rarely been able to use the vendors HDL source, if or when available, and always created my own from scratch ( I offer this as a guideline that reflect my personal goals and experience )
  • Be aware, especially for ADC evaluation boards that they are typically designed to evaluate an ADC component under very specific conditions. There is anti-aliasing filter on most cards and some are set up to do sub-sampling for specific carrier frequencies. Once you get the connections down this is the more complex issue and it's easy to end up with something that is not usable you your particular application.

If you have further questions I'm happy to reply.

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zygot Prolific Poster

zygot

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On 3/14/2020 at 4:01 PM, Steven Cornett said:

In general, if one is working with a project involving FMC cards using JESD204B, is that something best done with a Genesys 2 than the new Genesys ZU board?

The Genesys2 FMC implementation was very good. I have no doubt that the Genesys ZUx will be as good. The IO bank Vccio voltage ranges are different so many FMC mezzanine cards that work on the Genesys2 are not compatible with UltraScale+ devices. The ZU5 has GTH transceivers like the Genesis, but higher data rates. The PS/PL AXI interconnect is enhanced over Z7000 devices.

I haven't tried using the Geneysy2 FMC transceivers at 10 GHz. 

As to which one is the better platform, that depends on what you are doing. Do you need PL external memory? Do you want the added complexity of a ZYNQ PS? Is the application standalone; not needing a high speed data interface to an external device?

Personally I'm disappointed that the Genesys lineage has turned into a ZYNQ platform. I appears that we will be having ZYNQ with our supper whether we want it or not. This is, I presume, to be the future according to Xilinx.

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zygot Prolific Poster

zygot

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49 minutes ago, Steven Cornett said:

That's strange because Xilinx has UltraScale Kintex and Virtex

I assume that this comment is push back on my assumption on ZYNQ pervasiveness. It's not just about what parts are active. It's also about what's available and affordable. I'd love to see a Kintex UltraScale Genesys from Digilent. In fact I'd love to see affordable Kintex based FPGA boards from anyone. Have you checked your distributor for pricing and availability for even the "vintage" KC325T that is on the Genesys2 lately?

 

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Steven Cornett Member

Steven Cornett

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What the?!?

What is the explaination for this when the Zynq is so cheap.  The UltraScale+ version of the Xilinx board is not much more expensive than the Series 7 in most other boards.

This is completely out of proportion unless, like you say, Zynq is Xilinx' money maker and they want to steer people to it.

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zygot Prolific Poster

zygot

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Just saying that the world is more complicated than you might want to believe. One way to find this out is to design a board, build a 100 or so and then try to make the profit that you envisioned at the beginning the previous year. You can see where things are going by looking over the new Versal devices.

So when was the last time Digilent released a non-ZYNQ FPGA board? How many Genesys2 type boards do you know of for the price?

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