Do I have the right evaluation board?

[HelplessGuy]

Hi everyone,

I want to do a new project and I am looking for the right evaluation board for this.

Maybe you can give me an advice, which board.

The requirements are:

-ADC (2 simultaneous channels with 12 bit, 160kSpS)

-FFT (in a PL with 16k values)

-seriell bus

-enough memory for saving more than 64k values with a length of u16

I think the requirements are not very high, but I do not know what kind of board I should prefer for this.

Especially I guess, putting 16k values in a FFT is not that simple.

Thanks for all advice!

The HelplessGuy

[xc6lx45]

Hi,

I think you can get the resource utilization from the wizard, and you don't need hardware to synthesize a test design.

My guess is it'll fit into the smallest Artix (e.g. CMOD A7) but ultimately you have to check for yourself. I'd reserve 1 MBit (65k x 16) BRAM for data storage - it's too much hassle with an external memory chip, if avoidable.

There's a speed-area trade-off in FFT. I guess you'll manage to make it work with realistic settings, but better check with the IP wizard yourself.

If you go for XADC, double-check that the two ADC inputs you intend to use form a pair for phase-synchronous sampling (e.g. the CMOD A7 schematic shows the correct AD channel offset, I think it was 8).

[zygot]

There are a few things that you don't mention.. like what board you already own. I might be wrong but from reading your list of requirements I'm guessing that this list will change once you have a basic design working. You don't mention a constant data rate or latency requirement. These are the kinds of things that you should spend time anticipating up front. It's rarely satisfying to get 80% of a goal accomplished with no way to get to 100%. This is one of those projects where you can  build a solution before you actually spend money since there are a variety, depending on unmentioned details, of boards available that might suit your needs.

There is certainly no harm in picking a board supported by the free Vivado tools and building and simulating your design without actual hardware. You can always spend your money once you have a pretty good sense that a particular board works for your design.

In my experience there are two ways to develop FPGA projects. One involves a limitless budget and time expenditure with many restarts and the other involves some planning and creative approaches to getting more from less. You can probably guess which one I'd recommend.

[D@n]

@HelplessGuy,

Plus one to the quotes above, and again to the recommendations to simulate everything before letting it touch a board.

Just for reference, here's an example design on github that takes in a single analog/digital input from the PMod MIC3 (1Msps), applies a window function (Hanning), FFTs the result, and displays the measured energy spectra as a scrolling raster on an HDMI output.  The simulator will also display the result as a window on your screen.  Feel free to run it through Vivado and check out the resource usage, or even increase the size of the FFT to see how that impacts things.

Dan