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Altera_Forum's avatar
Altera_Forum
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13 years ago

interfacing to FFT megafunction (Avalon ST)

Hi all,

I am struggling to implement the FFT megafunction. IT builds and works ok with the generated testbench, but I cannot seem to wrap up the Avalon interface correctly

Am I being a bit thick? it looks fairly straight forward, but I seem to be struggling to talk 'Avalon'

Can anyone out there recall any 'gotchas' when they first started with this stuff?

Know of any wrapper function for the FFT megafunction? Or am I missing the point and it should be really easy?

I'm on quartus 9.1, quite agnostic about wether I use Verilog or VHDL

And that's got to be the lamest post I've ever made.....

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Yes, the Avalon-ST bus is picky.

    Make sure you have exactly the FFT size between the sink_sop and sink_eop signals. Otherwise your results will be incorrect. When simulating, validate the the sink_error = 2'b00 and the source_error == 2'b00

    Pete
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Ok, thanks I'll look again

    could easily have had 1 sample to few !

    Cheers

    Pete B