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Altera_Forum's avatar
Altera_Forum
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12 years ago

set up SignalTap trigger

Hello,

I have a long rectangle impulse, which can not be displayed in one acquisition of signalTap II.

I want to capture at two trigger time, one at rising edge of rectangle impulse, one at falling edge. and then display them at the same time. Please help me to do that.

Thanks,

6 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    Hi, one way to see this slow signal in SignalTap is to sample in a clock frequency two or three times the frequency of the impulse. and them set the trigger on the rising edge of that.

  • Altera_Forum's avatar
    Altera_Forum
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    You can separate the signaltap memory in two zones and trigger on a edge change.

  • Altera_Forum's avatar
    Altera_Forum
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    --- Quote Start ---

    You can separate the signaltap memory in two zones and trigger on a edge change.

    --- Quote End ---

    Do you mean option Sample depth...Segmented, where I can chose 2 8k samples or 4 4k samples?

    I don't know what it really mean. When I chose it, there's nowhere for me to chose which trigger for which segment. Confuse!
  • Altera_Forum's avatar
    Altera_Forum
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    Yes, it is the segmented. If you want to see only one cycle choose de 2 8k. It means that the memory will be divided in to parts one for the rising edge trigger and other for the falling edge.

  • Altera_Forum's avatar
    Altera_Forum
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    and the same trigger will be used on both segments. That's why I suggested to trigger on either edge, instead of rising or falling. That way you'll have a rising edge on one segment, and a falling edge on the other.

  • Altera_Forum's avatar
    Altera_Forum
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    I made two segments, put trigger in both edges. It works exactly as I want. First trigger actives at rising edge and It's saved to first segment, second trigger happen at falling edge and it's save to second segment. Until all segment are saved, signalTap displays data from memory.

    Thanks, That's really helpful.