Chapter 3: Using the Logic Analyzer in Timing or State Mode

Displaying Captured Data

Capacitive Loading on the Device Under Test

the actual write to this variable. Although the instruction is prefetched, the analyzer can be set to only trigger when the write is executed.

Excessive capacitive loading can degrade signals, resulting in suspicious data or even system lockup. All analysis probes add capacitive loading, as can custom probes you design for your device under test. To reduce loading, remove as many pin protectors, extenders, and adapters as possible.

Careful layout of your device under test can minimize loading problems and result in better margins for your design. This is especially important for systems running at frequencies greater than 50 MHz.

If there are filtered data holes in display memory

When an analyzer measurement occurs, acquisition memory is filled with data that is then transferred to the display memory of the analysis or display tools you are using, as needed by those tools. In normal use, this demand driven data approach saves time by not transferring unnecessary data.

Since acquisition memory is cleared at the beginning of a measurement, stopping a run may create a discrepancy between acquisition memory and the memory buffer of connected tools. Without a complete trace of acquisition memory, the display memory will appear to have 'holes' in it which appear as filtered data.

This situation will occur in these cases:

If you stop a repetitive measurement after analyzer data has been cleared and before the measurement is complete.

If a trigger is not found by the analyzer and the run must be stopped to regain control.

To make sure all of the data in a repetitive run is available for viewing:

1.In the workspace, attach a Filter tool to the output of the analyzer.

2.In the Filter, select "Pass Matching Data"

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Agilent Technologies 16760A If there are filtered data holes in display memory, This situation will occur in these cases