Digital Scope

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Updated2026-10-20
7 minute(s) read

Use the digital scope to view a graph of the expected waveform underneath the actual waveform using the pattern, timing set, and levels, including compare strobe locations, V_OH and V_OL levels, and expected drive levels. You can use the digital scope to help debug failures by verifying that the actual waveform accurately reflects what you expect based on what the pattern and timing define.

The Digital Pattern Editor generates digital scope waveforms by repeatedly bursting a pattern while changing levels and the timing of the strobe edge to determine the level of the waveform at each point in time.

Note The cycles or vectors on which you generate digital scope waveform points must be repeatable for every burst of the pattern. Some opcodes cause non-deterministic pattern execution. For example, conditional jumps might depend on a failed or matched pattern state. Such opcodes can cause errors and produce inaccurate results. Remove the pins with such compares from the pin list for the digital scope to avoid such inaccuracies. For example, you can configure the digital scope to start at a cycle. In that case, every burst must contain the specified cycle range at the same vector positions. If you configure the digital scope to start at a vector, that vector does not have to always execute on the same cycle. Specify the number of cycles to plot after the start vector cycle for each burst. The selected cycles must correspond to the same vectors in every burst.

Launching the Digital Scope

Use the following techniques to launch the digital scope:

Select View » Digital Scope.
Click the Show Digital Scope button on the pattern document toolbar.
Right-click a cell in the pattern document and select Use Digital Scope on Selected Pins Data from the context menu.
After you burst a pattern, right-click a cell in the History RAM View and select Use Digital Scope on Selected Pins Data from the context menu.

Running the Digital Scope

Use the Run Digital Scope and Abort Abort buttons on the toolbar to control the operation.

Note When running the Digital Pattern Editor in demo mode and executing a digital scope operation, beware of the following: The generated results reflect the actual pin states from the target pattern and the currently active timing values. The results do not reflect a realistic execution of patterns. Use the pattern waveform view to see a graph of the pattern without requiring the use of digital pattern instruments.

Reading the Digital Scope

The digital scope graph can contain the following components:

Sampled Point — Indicates a particular sample. These points disappear if the number of samples available provides sufficient resolution to draw a smooth signal.
Non-Converging Point — Indicates a potentially inaccurate or noisy sample. Common causes include high signal noise, non-deterministic patterns, and sharp rising or falling signal edges.
Cycle Boundary — Indicates the cycle boundaries.
VOH and VOL Levels — Indicates the V_OH and V_OL levels per pin.
Driving — Indicates a driving pin state (0, 1, D).
Not Driving — Indicates a non-drive pin state (L, H, X, V, M, E). An up or down arrow placed at the strobe time the time set specifies indicates the strobe edge of compare states.
Unknown State — Indicates that sufficient drive-state information is unavailable for a section of the digital signal. Examples include samples before the Drive On edge at the start of a pattern and samples after a discontinuity. An unresolved dash (-) pin state can also cause an unknown state. Some drive states depend on information outside the pattern, such as a source waveform.

Configuring the Digital Scope

Use the Pattern, Pins/Pin Groups, and Site controls in the Digital Scope Configuration section to configure digital scope execution settings. Use the type-ahead drop-down menu to select valid pins and valid pin groups.

Click the Enabled Sites button

to launch the Sites dialog box. The dialog box can enable or disable sites in the active pin and channel map for debugging. Disabled sites do not return results. The Sweep Ranges section contains controls for sweep operation settings. To configure those settings, use the following controls:

Start Vector
Cycle Offset
Number of Cycles
Number of Steps
Voltage Resolution

The project stores the settings for the digital scope but not the plot data itself.

Note Set the number of steps according to the timing accuracy that the digital pattern instrument supports. A smaller resolution does not improve waveform accuracy.

Use the expander Expander icon used to expand or collapse a section. Collapse expander button. buttons to expand or collapse the settings section to create a larger display area for the digital scope.

When you right-click a cell in the pattern document and select Use Digital Scope on Selected Pins and Vectors from the context menu or right-click a cell in the History RAM View and select Use Digital Scope on Selected Pins and Cycles from the context menu, the digital scope preconfigures the Start Vector, Cycle Offset, Number of Cycles, Pins/Pin Groups, and Pattern settings for the digital scope operation based on the vector or cycle you selected.

You can also use the Site drop-down menu on the toolbar to select the site for which you want to display plot results.

While the digital scope runs, vertical red points indicate the current evaluation time. The tool evaluates the level on each pin at that time. Green circles indicate fully evaluated points and always display while executing.

Configuring a small number of steps might result in incomplete waveform information if the signal changes rapidly.

Instrument settings return to their original values when the digital scope operation completes or when you abort the operation.

Use the two cursors on the digital scope to display the timing and measured voltage values for all pins. Drag the two cursors independently to measure the time offset between their positions. The digital scope displays the value in the upper-left corner. The cursors reset to the beginning of the digital scope plot when you restart the digital scope operation.

Use the Toggle Expected Waveforms on Top button to change whether the actual waveform overlays the expected waveform. Use the Always Show Sampled Points button to toggle the display of all points on the plot. The graph always displays the sampled points while executing. Use the Show Levels at Cursor button to toggle the display of the per-pin voltage levels at the locations of the cursors.

Use the buttons above the digital scope to control panning and zooming. The pan locations and the zoom locations reset to center when you restart the digital scope operation.

The document stores the specified digital scope settings, but not the graph data itself, in the corresponding .digiprojcache file for the project.

Note Once the Digital Pattern Editor calculates and applies TDR values, the timing of the Digital Scope is now relative to the DUT. The Digital Scope displays the time when the DUT drove or received the signal. The displayed time does not represent when a digital pattern instrument drove or received the signal. Use the Digital Scope to validate DUT signals. The Digital Scope shows the expected DUT waveform signals in blue.

Use the Halt Vector control to specify the vector index at which to halt the pattern in the digital scope. This vector should not have any opcodes.

Note The default value for this control is -1 and results in bursting the entire pattern.

Saving the Digital Scope Information

Use the Save Plot Data to CSV File button Save Pin Failures on the toolbar or press <Ctrl+S>. The Digital Scope saves the actual and expected plot data for the active site to a .csv file. Use the Save Screenshot to PNG button Save Digital Scope as PNG on the toolbar. The Digital Scope saves a screenshot of the state and plot data of the digital scope as an image file. You must expand the settings section to include it in the image.

Keyboard Shortcuts within the Digital Scope


Action	Shortcut
Run Digital Scope	F5
Control panning	<Ctrl+left-click> and drag
Zoom on a region you select	<Shift+left-click> and drag
Save actual and expected plot data for the active site to a .csv file	<Ctrl+S>

Related Information

Bursting Patterns and Viewing Results
Pattern Grid View
Select the Grid tab on the pattern document toolbar to launch the pattern grid view. Use this view to see components of the binary pattern file, including time sets, labels, opcodes, vector numbers, pin state data that indicates drives and compares, comments for each vector, exported labels, and comments from the top of the file. Use the pattern waveform view for a graph-based representation of the pattern. You can select and right-click vectors in the pattern grid view and select Show Vectors in Waveform View from the context menu to launch the pattern waveform view. You can also select the Waveform tab on the pattern document toolbar to launch the pattern waveform view. An asterisk (*) next to a filename in the Project Explorer window and in the document tab indicates that the file has been modified but not saved.
History RAM View
Use this view to see the History RAM results for the flow of pattern execution for the last pattern burst across all executed patterns for the number of samples you specify in the Instrument Settings pane, including vectors with repeat opcodes. The view also includes the corresponding time sets, labels, opcodes, pattern names, vectors/cycles, pin state data, and comments. Rebursting a pattern overwrites the data in the History RAM View.

NI-Digital Pattern User Manual

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