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JohnDuq's avatar
JohnDuq
Icon for New Contributor rankNew Contributor
5 years ago
Solved

signaltap state trigger false positive

I have an issue were an internal memory block is reporting data that is shifted by 8 bytes. I'm trying to set up a SignalTap trigger to catch the discrepancy. The trigger is activating when it shou...
  • JohnDuq's avatar
    JohnDuq
    5 years ago

    I dropped this back to a simpler filter and got it to work

    Condition 1 : data = 3dcccccdh

    Condition 2: address = 403xh

    Condition 4: address = 683xh

    Trigger on Condition1 && !Condition 2 && !Condition3=4

    This won't catch a 4 byte data shift but it will catch an 8 byte or larger shift. That works for now.

    Thanks for all your help.

JohnDuq's avatar
JohnDuq
Icon for New Contributor rankNew Contributor
5 years ago

Thanks for the response. Under normal operation I'm getting a trigger every 1 ms, and I have to collect data for many hours before the error occurs, and it sometimes occurs for a few seconds, then recovers for a few seconds, then occurs again... It seems like with your technique i would need a 2nd level of filter to throw out the normal triggers or stop collecting after I get a trigger on an abnormal address. That especially doesn't help because currently i can only capture 512 cycles of my SignalTap clock; I could maybe break that down to about 32 segments of 16-cycles each.

You may have pointed me in the right direction though. I had set my 'storage qualifier' to state-based, but missed that there was a 'Trigger flow control' down below that was still set to 'continuous'. I changed that to 'State-based'. Unfortunately now when I compile I get these cryptic error messages:

Error (272006): Invalid Signal Tap custom flow control description was specified.
Error (287078): Assertion error: Valid clear box generator not found or Errors encountered during clear box generation
Error (12154): Can't elaborate inferred hierarchy "sld_signaltap:auto_signaltap_0|sld_signaltap_impl:sld_signaltap_body|sld_signaltap_implb:sld_signaltap_body|sld_ela_control:ela_control|sld_ela_trigger_flow_sel:\generated:ela_trigger_flow_mgr_entity"
Error: Quartus Prime Analysis & Synthesis was unsuccessful. 3 errors, 27 warnings
Error: Peak virtual memory: 4912 megabytes
Error: Processing ended: Wed Dec 02 23:44:23 2020
Error: Elapsed time: 00:00:15
Error: Total CPU time (on all processors): 00:00:22
Error (293001): Quartus Prime Full Compilation was unsuccessful. 5 errors, 27 warnings

Any clue where I go from here?

sstrell's avatar
sstrell
Icon for Super Contributor rankSuper Contributor
5 years ago

No, that's the beauty of the segmented buffer. Just let it sit and every time the trigger occurs, one segment fills, even if it's hours between the trigger events happening. You could certainly add a second trigger condition for further filtering if necessary.

As you found, state-based can be set for the trigger flow itself and for storage qualification, which I've always found weird because with a state-based trigger, you can selectively choose exactly which samples you want to capture. In any case, I don't know if that's what's causing the error, but if you want to use the state-based trigger, set the storage qualification to Continuous and the trigger flow to state-based. You can also use a segmented buffer with the state-based trigger by using the segment_trigger command in the "code" instead of just "trigger."

  • JohnDuq's avatar
    JohnDuq
    Icon for New Contributor rankNew Contributor
    5 years ago

    Thanks. it looks like when I had 'Storage Qualifier' set to 'state-based' and Trigger set to 'state-based' it caused the errors causing SignalTap to not be instantiated. At least I can compile again.

    Now back to debugging this flaky trigger...

    • JohnDuq's avatar
      JohnDuq
      Icon for New Contributor rankNew Contributor
      5 years ago

      I dropped this back to a simpler filter and got it to work

      Condition 1 : data = 3dcccccdh

      Condition 2: address = 403xh

      Condition 4: address = 683xh

      Trigger on Condition1 && !Condition 2 && !Condition3=4

      This won't catch a 4 byte data shift but it will catch an 8 byte or larger shift. That works for now.

      Thanks for all your help.