18.104.22.168.6.1. Storage Qualification Feature for the State-Based Trigger Flow
This trigger flow description contains three trigger conditions that occur at different times after you click Start Analysis:
State 1: ST1: if ( condition1 ) start_store; else if ( condition2 ) trigger value; else if ( condition3 ) stop_store;
When you apply the trigger flow to the scenario in the figure:
- The Signal Tap logic analyzer does not write into the acquisition buffer until Condition 1 occurs (sample a).
- When Condition 2 occurs (sample b), the logic analyzer evaluates the trigger value command, and continues to write into the buffer to finish the acquisition.
- The trigger flow specifies a stop_store command at sample c, which occurs m samples after the trigger point.
- If the data acquisition finishes the post-fill acquisition samples before Condition 3 occurs, the logic analyzer finishes the acquisition and displays the contents of the waveform. In this case, the capture ends if the post-fill count value is < m.
- If the post-fill count value in the Trigger Flow description 1 is > m samples, the buffer pauses acquisition indefinitely, provided there is no recurrence of Condition 1 to trigger the logic analyzer to start capturing data again.
The Signal Tap logic analyzer continues to evaluate the stop_store and start_store commands even after evaluating the trigger. If the acquisition paused, click Stop Analysis to manually stop and force the acquisition to trigger. You can use counter values, flags, and the State diagram to help you perform the trigger flow. The counter values, flags, and the current state update in real-time during a data acquisition.