ADC fmc for Genesys 2 board

[Ronas12]

Hi, I have the FL9627 AD fmc from alinx.

I want to use this on Genesys 2 board for get analog signals and output dvi videos using ipcore rgb2dvi (digilent).

can anyone have a code for this fmc or alternatively can give me another ADC fmc that match for this board?

[zygot]

Gee, wouldn't it be great if someone made a HPC FMC mezzanine card with standard, wide, and transceiver SYZYGY ports?

Gee, wouldn't it be nice if Digilent, maker FPGA boards with FMC equipped connectors, had the gumption to make any FMC mezzanine cards to support their own products?

Unfortunately, things aren't great or nice. If you want to use an FMC card with your FPGA board you have two basic options. You can find a vendor of FMC mezzanine cards that have the functionality that you are looking for. Make sure that they have a demo using that card with your board, and that they supply source code and a way to build a project in the version of your tools. Analog Devices sells A/D and D/A converters. They sell evaluation cards, sometimes with FMC or HSMC connectors, and provide limited HDL support to build a demo for that card. There may be others, but I don't know of any.

Your second option is to find an FMC mezzanine card and do the work of making sure that it's compatible with your FPGA board. If LVDS or clocking is involved there is a good chance that there will be issues. It depends on the devices involved and pin assignments. Once you've established that there are no obvious issues of compatibility, you can then create you own HDL design to use the mezzanine board's functionality.

With either option, you are unlikely to get exactly what you want. Sometimes you get lucky and find something close enough. If what you want to do is capture analog signals ( that's a whole discussion ) and use an HDMI connector to plot the signals on a monitor, there's 0% chance of finding an add-on card provided with HDL source code such an application.

Edited May 3, 2023 by zygot

[Ronas12]

Well, first thank you for the response.

We didnt want to take the signals and convert them into a DVI signals on the FMC board.

what we need is just to have an A/D add on. We are trying to get samples from the A/D and then proccess them in the FPGA and make a video signal and output them using the HDMI connector. Its important to say that all we need is just the A/D FMC (with the HDL code) for our development board, Genesys 2.

Secondly, the FL9627 works with LVDS but in the XDC of the Genesys the fmc is connected to LVCMOS lines. Can we work with the FL9627 or should we find a new fmc A/D add on.

[zygot]

2 hours ago, Ronas12 said:

Can we work with the FL9627 or should we find a new fmc A/D add on.

I believe that I addressed this in my original post. It depends on the converter. It depends on whether pin assignments on the carrier board and mezzanine card are compatible. This is especially important for clock signals going into the FPGA as there are rules based on clocking regions and IO banks. This is especially true for LVDS clock schemes with separate reference and data clocking. Does the FL9627 have a demo with source for use with the Genesys2?

Due to FPGA complexity and differences between devices FMC isn't a "Plug and Play" standard. This means that you have to do your own homework or take a chance on someone else's claims. I've evaluated a LOT of FMC mezzanine cards for the Nexys Video and Genesys2 and am not talking out of my butt. But, no one should do something or not do something based solely on anything that I post.

Ask yourself this: if someone were to post an answer that was "sure why not?" , how big of a risk taker are you?

I suppose that you could look at the list of FMC mezzanine boards that Digilent certifies is guaranteed to work with any of their FPGA boards equipped with an FMC connector. Don't bother looking as there is no such list. In fact, if you  browse through all of the Digilent posts on the subject the only thing that you will find is that Digilent does not test or certify that any FMC card will work with any of their FPGA boards.

Either you know how to do the analysis for yourselves or you don't. I can't help you do your own due diligence. I might be able to help you figure out how to do the analysis for yourselves.

As I mentioned, a whole other line of inquiry is whether or not a ADC card converter and analog front end is suitable for acquiring the kind of signal that you want to convert to a digital data stream. There are an awful lot of details in converting analog into digital that can be problematic.

I realize that this isn't the answer that you want. I believe that it's likely the most informed and honest answer that you can hope to get.

Edited May 4, 2023 by zygot

[zygot]

57 minutes ago, Ronas12 said:

We didnt want to take the signals and convert them into a DVI signals on the FMC board.

Yeah, I got that from the original post.

[Ronas12]

6 hours ago, zygot said:

As I mentioned, a whole other line of inquiry is whether or not a ADC card converter and analog front end is suitable for acquiring the kind of signal that you want to convert to a digital data stream. There are an awful lot of details in converting analog into digital that can be problematic

 

6 hours ago, zygot said:

I've evaluated a LOT of FMC mezzanine cards for the Nexys Video and Genesys2 and am not talking out of my butt.

Is there such an A/D FMC card that you know that working well with Genesys2 with a demo codes/project?

If not, is there any other options that we can use to solve our problem (all of the diagram, code and more are ready and we just stuck on how to get this signals into the FPGA)
More details about the features of the A/D that we need:

50MHZ

Analog signals of 10Vptp

Between 12bit to 16 bit

The signals are kind of sine waves/triangle waves.

 

If you can help us with this issue, its will be great, thanks from advance.

[zygot]

I have not found a good general purpose, reasonably priced, A/D card that I've wanted to use for either the Nexys Video or Genesys2 for signals > 10 MHz for any of my project needs.

Digilent makes excellent SYZYGY compatible A/D pods for signals in the 0-30 MHz range. This is why I made a reference to them in my first post. Unfortunately, they don't make an FPGA board that's suitable for your needs.

Is 50 MHz the sampling frequency or the high end of your bandwidth of interest? Some converters, like those using wide-band transformer coupling have no DC response and poor low frequency response. This may or may not be a problem. Often A/D cards from component vendors selling evaluation hardware have analog front ends that aren't suitable for general purpose applications. This is especially true for converters sampling at 100 MHz and above. A lot of those converters are for communications and are for narrow-band sampling applications.

There aren't a lot of A/D cards supporting an Fs of 100 MHz or higher that accept 10V pk-pk inputs. The analog conditioning circuitry that sits between a signal and the converter is as important, or even more important than the converter specs. There just aren't many FMC A/D mezzanine cards, that aren't really expensive, to choose from for general purpose use. 

Some A/D converters have full-power analog bandwidths that are much lower than the supported sampling frequency.

Input impedance seen by the signal you are trying to capture is usually very important to take into consideration. Can your signal source drive a 50 ohm terminated load?

Out of curiosity, I did take a look at the limited information for the FL9627. This is supposedly available through Amazon in western markets. Personally, I don't trust Amazon as a seller for big ticket technology purchases. On the face of it, the price is reasonable. It appears to be compatible with 1.8V LVDS logic which the Genesys2 can support. Getting detailed specifications is a problem, which would put me off. It might be worth your time to check it out. You need to understand Series7 clocking rules, LVDS, IO etc, all of this information is available through the Vivado Documentation Navigator that was installed. You will also need schematics for both the Genesys2 and the FL9627. Diligent provides schematics for the Genesys2.  [edit] you will also need the converter datasheet fo understand the data interface.  I haven't gone to the trouble of looking at the datasheet for the converter on that board. LVDS interfacing can be pretty straight-forward or very complicated for high data rate to clock rate ratio if SERDES is involved ( 8:1 and above ). It all has to be checked out. SERDES be problematic depending on the FPGA device and pin assignments.

I haven't tried making an exhaustive discourse on everything that you might need to consider in picking a suitable converter card, but these are the basics. Beware that most A/D converters have an EOB that is much lower than the data width. Ideally, you want the ability to make the signal that the converter sees as close the pk-pk input range as possible or you lose dynamic range. Do you need a 4 quadrant signal range? AC or DC coupling? The list goes on and on.

Unfortunately, like everything else in recent years, there's been a huge consolidation in the converter vendor market. ADI is pretty much the only game in town for newer converter products in the 10 MHZ or higher range. Fortunately, for a few products they do have reasonable EVM offerings, sometimes with an FMC connector, and make a reasonable attempt at providing FPGA support. So I'd suggest seeing what's available, with projec support for Vivado there. You will still need to do you homework, though the Genesys2 borrows a lot from the KC705.

So, gee, wouldn't it be great if Digilent made an FMC mezzanine card with SYZYGY ports that worked with their own FPGA boards?

Edited May 7, 2023 by zygot

[zygot]

Oh, I forgot to mention that ADI has some pretty good information for scientists and engineers who don't have a lot of experience with converter design concepts. Unfortunately., what they don't offer is help deciphering the sometimes cryptic, often misleading, or missing information in the datasheets and marketing hype ... and unfortunately, there's a lot of that... (including their own). Anyway, ADI has some E-books in pdf format that are free to download and read through. At least you get an introduction to the basics, and converter types that are available. I don't know what's happened ot Texas Instruments. They offer a few converter products, but last time I tried to search for products I couldn't find any useful website.

I don't consider myself to be an A/D converter expert. I do have a fair amount of experience though and know enough on the subject to (usually) ask the right questions. Asking the wrong questions is no help. Before you can ask the right questions you need to be fairly well read and informed, at least for many engineering topics. Edited May 5, 2023 by zygot