Quartus® Prime Pro Edition User Guide: Debug Tools

ID 683819
Date 7/08/2024
Public
Document Table of Contents

2.4.6.6.1. Post-fill Count

In a custom state-based triggering flow with the segment_trigger and trigger buffer control actions, you can use the post-fill_count argument to specify a custom trigger position.

  • If you do not use the post-fill_count argument, the trigger position for the affected buffer defaults to the trigger position you specified in the Setup tab.
  • In the trigger buffer control action (for non-segmented buffers), post-fill_count specifies the number of samples to capture before stopping data acquisition.
  • In the segment_trigger buffer control action (for segmented buffer), post-fill_count specifies a data segment.
Note: In the case of segment_trigger, acquisition of the current buffer stops immediately if a subsequent triggering action is issued in the next state, regardless of the current buffer's post-fill count. The logic analyzer discards the remaining unfilled post-count acquisitions in the current buffer, and displays them as grayed-out samples in the data window.

When the Signal Tap data window displays the captured data, the trigger position appears as the number of post-count samples from the end of the acquisition segment or buffer.

Sample Number of Trigger Position = (N – Post-Fill Count)

In this case, N is the sample depth of either the acquisition segment or non-segmented buffer.