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Altera_Forum's avatar
Altera_Forum
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17 years ago

SignalTap Selective Sampling

Hi everyone,

I'm trying to sample my signals, the problem is I don't have enough ram blocks in my DE2 board to capture for long enough, so I though may be I can capture selectively. The trigger, however, only directs the analyzer when to start. So I thought it might be the "trigger out" condition that I should use to make it stop sampling during unwanted periods, am I right? But now the problem is apparently there's "5 cycles" latency on that, but 5 cycles is all I wanted to save between my samplings :) Is there any other way of doing this, so that I don't pay the 5 cycles latency? Thanks.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    --- Quote Start ---

    I'm trying to sample my signals, the problem is I don't have enough ram blocks in my DE2 board to capture for long enough, so I though may be I can capture selectively.

    --- Quote End ---

    A feature available in the last couple of Quartus versions might help. From the QII 8.0 handbook, Volume 3, Section V, Chapter 14:

    --- Quote Start ---

    The custom state-based triggering flow allows for more efficient use of the space available in the acquisition buffer because only specific samples of interest are captured.

    --- Quote End ---

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Thanks for the help. Beside that, I think the "Segmented" trigger is what I wanted, though it's not really clear.

    Cheers,

    Kaveh