NI-velmurugan · Nov 5, 2026 · Nov 5, 2026 · Nov 11, 2026 · Nov 12, 2026 · Nov 12, 2026
@@ -558,6 +558,7 @@
 #### [nidigital] Unreleased
 - Added
   - (Common) Added `nitlsconfig[grpc]>=1.0.0a2` to the optional gRPC dependencies.
+  - Added the `nidigital_unload_and_reload_specifications_file.py` example.
 - Changed
 - Removed
 

@@ -30,3 +30,12 @@ nidigital_ppmu_source_and_measure.py
    :encoding: utf8
    :caption: `(nidigital_ppmu_source_and_measure.py) <https://github.com/ni/nimi-python/blob/master/src/nidigital/examples/ppmu_source_and_measure/nidigital_ppmu_source_and_measure.py>`_
 
+nidigital_unload_and_reload_specifications_file.py
+--------------------------------------------------
+
+.. literalinclude:: ../../src/nidigital/examples/unload_and_reload_specifications_file/nidigital_unload_and_reload_specifications_file.py
+   :language: python
+   :linenos:
+   :encoding: utf8
+   :caption: `(nidigital_unload_and_reload_specifications_file.py) <https://github.com/ni/nimi-python/blob/master/src/nidigital/examples/unload_and_reload_specifications_file/nidigital_unload_and_reload_specifications_file.py>`_
+
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PinLevelsFile xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" schemaVersion="1.0" xmlns="http://www.ni.com/Semiconductor/PinLevels">
+  <PinLevelsSheet>
+    <DigitalPinLevelSets>
+      <DigitalPinLevelSet pin="SDATA">
+        <Vil>0</Vil>
+        <Vih>DC.Vdd</Vih>
+        <Vol>DC.Vol</Vol>
+        <Voh>DC.Voh</Voh>
+        <TerminationMode>HighZ</TerminationMode>
+      </DigitalPinLevelSet>
+    </DigitalPinLevelSets>
+  </PinLevelsSheet>
+</PinLevelsFile>
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PinMap schemaVersion="1.5" xmlns="http://www.ni.com/TestStand/SemiconductorModule/PinMap.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+	<Instruments>
+		<NIDigitalPatternInstrument name="PXI1Slot2" numberOfChannels="32" group="Digital" />
+		<NIDigitalPatternInstrument name="PXI1Slot3" numberOfChannels="32" group="Digital" />
+	</Instruments>
+	<Pins>
+		<DUTPin name="SDATA" />
+	</Pins>
+	<PinGroups>
+		<PinGroup name="Digital_Pins">
+			<PinReference pin="SDATA" />
+		</PinGroup>
+		<PinGroup name="All_Pins">
+			<PinReference pin="SDATA" />
+		</PinGroup>
+	</PinGroups>
+	<Sites>
+		<Site siteNumber="0" />
+		<Site siteNumber="1" />
+		<Site siteNumber="2" />
+		<Site siteNumber="3" />
+	</Sites>
+	<Connections>
+		<Connection pin="SDATA" siteNumber="0" instrument="PXI1Slot2" channel="25" />
+		<Connection pin="SDATA" siteNumber="1" instrument="PXI1Slot2" channel="17" />
+		<Connection pin="SDATA" siteNumber="2" instrument="PXI1Slot3" channel="9" />
+		<Connection pin="SDATA" siteNumber="3" instrument="PXI1Slot3" channel="1" />
+	</Connections>
+</PinMap>
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<SourceFile Checksum="DD1093EC813C28D903B23CEB42720E5F" Timestamp="1D52532198AA775" xmlns="http://www.ni.com/PlatformFramework">
+	<SourceModelFeatureSet>
+		<ParsableNamespace AssemblyFileVersion="5.3.1.50153" FeatureSetName="Digital Pattern Editor" Name="http://www.ni.com/PatternBasedDigital" OldestCompatibleVersion="4.5.0.0" Version="4.6.0.49152" />
+		<ParsableNamespace AssemblyFileVersion="5.3.1.50153" FeatureSetName="Editor" Name="http://www.ni.com/PlatformFramework" OldestCompatibleVersion="5.2.0.49153" Version="5.2.0.49153" />
+		<ApplicationVersionInfo Build="5.3.1.50153" Name="Digital Pattern Editor" Version="19.0.0" />
+	</SourceModelFeatureSet>
+	<ShmooSetupDefinition xmlns="http://www.ni.com/PatternBasedDigital">
+		<Shmoo Id="1" PatternName="demo_pattern_no_hw" ShmooPlotMode="EdgeTraversal">
+			<ShmooAxisSetup Id="2" Name="X-Axis" NumberOfSteps="50" PinItems="SDATA" ShmooType="Spec" SpecVariable="AC.Strobe" Start="0" Stop="10 n" TimeSets="SPI_IO_SHMOO" />
+			<ShmooAxisSetup Id="3" Name="Y-Axis" PinItems="SDATA" ShmooType="Spec" SpecVariable="DC.Voh" Start="0" Stop="5" />
+		</Shmoo>
+	</ShmooSetupDefinition>
+</SourceFile>
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Specifications xmlns:f="http://www.ni.com/schemas/Semiconductor/Formula.xsd" schemaVersion="1.0" xmlns="http://www.ni.com/schemas/Semiconductor/Specifications.xsd">
+  <Section name="DC">
+    <f:Formula symbol="Vdd">
+      <f:Definition>5.250000E+0</f:Definition>
+    </f:Formula>
+    <f:Formula symbol="Voh">
+      <f:Definition>DC.Vdd - 1</f:Definition>
+    </f:Formula>
+    <f:Formula symbol="Vol">
+      <f:Definition>0.4</f:Definition>
+    </f:Formula>
+  </Section>
+  <Section name="AC">
+    <f:Formula symbol="Frequency">
+      <f:Definition>100 M</f:Definition>
+    </f:Formula>
+    <f:Formula symbol="Period">
+      <f:Definition>1 / AC.Frequency</f:Definition>
+    </f:Formula>
+    <f:Formula symbol="Strobe">
+      <f:Definition>0.4*AC.Period</f:Definition>
+    </f:Formula>
+  </Section>
+</Specifications>
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<TimingFile xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" schemaVersion="1.0" xmlns="http://www.ni.com/Semiconductor/Timing">
+  <TimingSheet>
+    <TimeSets>
+      <TimeSet name="DriveNext">
+        <Period>AC.Period</Period>
+        <PinEdges>
+          <PinEdge pin="SDATA">
+            <ReturnToLow>
+              <On>AC.Period</On>
+              <Data>1.25*AC.Period</Data>
+              <Return>1.75*AC.Period</Return>
+              <Off>2*AC.Period</Off>
+            </ReturnToLow>
+            <CompareStrobe>
+              <Strobe>AC.Strobe</Strobe>
+            </CompareStrobe>
+            <DataSource>Pattern</DataSource>
+            <Comment>we are sourcing and capturing on the same pin, so we move the drive edges into the subsequent vector period</Comment>
+          </PinEdge>
+        </PinEdges>
+      </TimeSet>
+      <TimeSet name="wait">
+        <Period>3 µs</Period>
+        <PinEdges>
+          <PinEdge pin="All_Pins">
+            <DriveNonReturn>
+              <On>0</On>
+              <Data>0</Data>
+              <Off>AC.Period</Off>
+            </DriveNonReturn>
+            <CompareStrobe>
+              <Strobe>AC.Strobe</Strobe>
+            </CompareStrobe>
+            <DataSource>Pattern</DataSource>
+          </PinEdge>
+        </PinEdges>
+      </TimeSet>
+    </TimeSets>
+  </TimingSheet>
+</TimingFile>
@@ -0,0 +1,130 @@
+#!/usr/bin/python
+
+import argparse
+import nidigital
+import os
+import random
+import shutil
+import sys
+import tempfile
+from xml.etree import ElementTree
+
+SPECS_NAMESPACE = 'http://www.ni.com/schemas/Semiconductor/Specifications.xsd'
+FORMULA_NAMESPACE = 'http://www.ni.com/schemas/Semiconductor/Formula.xsd'
+NAMESPACES = {'s': SPECS_NAMESPACE, 'f': FORMULA_NAMESPACE}
+ElementTree.register_namespace('', SPECS_NAMESPACE)
+ElementTree.register_namespace('f', FORMULA_NAMESPACE)
+
+SOURCE_WAVEFORM_NAME = 'demo_src_wfm'
+CAPTURE_WAVEFORM_NAME = 'demo_waveform'
+SOURCE_PIN = 'SDATA'
+SAMPLE_WIDTH = 32
+NUMBER_OF_SAMPLES = 32
+
+
+def _sweep_values(start, stop, steps):
+    if steps == 1:
+        return [start]
+    return [start + i * (stop - start) / (steps - 1) for i in range(steps)]
+
+
+def _update_specification_values(specs_file_path, new_values):
+    # new_values maps '<Section>.<Symbol>' to the new definition for that specification
+    specs_tree = ElementTree.parse(specs_file_path)
+    for spec_name, value in new_values.items():
+        section_name, formula_symbol = spec_name.split('.')
+        definition_element = specs_tree.find("s:Section[@name='{}']/f:Formula[@symbol='{}']/f:Definition".format(section_name, formula_symbol), NAMESPACES)
+        definition_element.text = repr(value)
+    specs_tree.write(specs_file_path, encoding='utf-8', xml_declaration=True)
+
+
+def _count_mismatched_bits(expected_words, actual_words):
+    return sum(bin(expected_word ^ actual_word).count('1') for expected_word, actual_word in zip(expected_words, actual_words))
+
+
+def example(resource_name, options, x_spec_name, x_start, x_stop, x_steps, y_spec_name, y_start, y_stop, y_steps):
+    example_dir = os.path.join(os.path.dirname(__file__))
+
+    pin_map_filename = os.path.join(example_dir, 'PinMap.pinmap')
+    pattern_filename = os.path.join(example_dir, 'demo_pattern_no_hw.digipat')
+    capture_waveform_filename = os.path.join(example_dir, 'demo_waveform.digicapture')
+    original_spec_filename = os.path.join(example_dir, 'Specifications.specs')
+    levels_filename = os.path.join(example_dir, 'PinLevels.digilevels')
+    timing_filename = os.path.join(example_dir, 'Timing.digitiming')
+
+    # Work on a temporary copy so the specifications file shipped with the example is never modified
+    with tempfile.TemporaryDirectory() as temp_dir, \
+            nidigital.Session(resource_name=resource_name, options=options) as session:
+        temp_spec_filename = os.path.join(temp_dir, 'Specifications.specs')
+        shutil.copy(original_spec_filename, temp_spec_filename)
+
+        session.load_pin_map(pin_map_filename)
+        session.load_pattern(pattern_filename)
+
+        # Source random data; reg0 sets the number of source and capture loops used by the pattern
+        source_waveform_data = [random.getrandbits(SAMPLE_WIDTH) for _ in range(NUMBER_OF_SAMPLES)]
+        session.write_sequencer_register(nidigital.SequencerRegister.REGISTER0, len(source_waveform_data) * SAMPLE_WIDTH)
+        session.pins[SOURCE_PIN].create_source_waveform_serial(SOURCE_WAVEFORM_NAME, nidigital.SourceDataMapping.BROADCAST, SAMPLE_WIDTH, nidigital.BitOrder.MSB)
+        session.write_source_waveform_broadcast(SOURCE_WAVEFORM_NAME, source_waveform_data)
+
+        session.create_capture_waveform_from_file_digicapture(CAPTURE_WAVEFORM_NAME, capture_waveform_filename)
+
+        session.load_specifications_levels_and_timing(temp_spec_filename, levels_filename, timing_filename)
+        session.apply_levels_and_timing(levels_filename, timing_filename)
+
+        total_bits = len(source_waveform_data) * SAMPLE_WIDTH
+        print('Start sweeping specifications')
+        print('Fraction of mismatched capture bits for each ({}, {}) pair:'.format(x_spec_name, y_spec_name))
+        for y_value in _sweep_values(y_start, y_stop, y_steps):
+            for x_value in _sweep_values(x_start, x_stop, x_steps):
+                # Only the specifications are unloaded, so reload only them; the levels and timing sheets are still loaded
+                session.unload_specifications(temp_spec_filename)
+                _update_specification_values(temp_spec_filename, {x_spec_name: x_value, y_spec_name: y_value})
+                session.load_specifications_levels_and_timing(specifications_file_paths=temp_spec_filename)
+                session.apply_levels_and_timing(levels_filename, timing_filename)
+
+                session.burst_pattern(start_label='startdemo')
+                site_number, captured_waveform = next(iter(session.fetch_capture_waveform(CAPTURE_WAVEFORM_NAME, len(source_waveform_data)).items()))
+                mismatch_fraction = _count_mismatched_bits(source_waveform_data, captured_waveform) / total_bits
+                print('Site {}: {}={:g}, {}={:g}: {:.4f}'.format(site_number, x_spec_name, x_value, y_spec_name, y_value, mismatch_fraction))
+
+        print('Done sweeping specifications')
+
+        session.selected_function = nidigital.SelectedFunction.DISCONNECT
+
+
+def _main(argsv):
+    parser = argparse.ArgumentParser(description='Demonstrates how to unload and reload a specifications file while sweeping two specification values and measuring the capture waveform bit errors at each point.', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    parser.add_argument('-n', '--resource-name', default='PXI1Slot2,PXI1Slot3', help='Resource name of a NI digital pattern instrument. Ensure the resource name matches the instrument name in the pinmap file.')
+    parser.add_argument('-s', '--simulate', default='True', choices=['True', 'False'], help='Whether to run on simulated hardware or real hardware')
+    parser.add_argument('-xn', '--x-spec-name', default='AC.Strobe', help='Specification to sweep along the X axis, as <Section>.<Symbol>.')
+    parser.add_argument('-xs', '--x-start', default=0.0, type=float, help='First value of the X axis sweep.')
+    parser.add_argument('-xe', '--x-stop', default=1e-8, type=float, help='Last value of the X axis sweep.')
+    parser.add_argument('-xc', '--x-steps', default=5, type=int, help='Number of values in the X axis sweep.')
+    parser.add_argument('-yn', '--y-spec-name', default='DC.Voh', help='Specification to sweep along the Y axis, as <Section>.<Symbol>.')
+    parser.add_argument('-ys', '--y-start', default=0.0, type=float, help='First value of the Y axis sweep.')
+    parser.add_argument('-ye', '--y-stop', default=5.0, type=float, help='Last value of the Y axis sweep.')
+    parser.add_argument('-yc', '--y-steps', default=5, type=int, help='Number of values in the Y axis sweep.')
+    args = parser.parse_args(argsv)
+
+    example(args.resource_name,
+            'Simulate=1, DriverSetup=Model:6571' if args.simulate == 'True' else '',
+            args.x_spec_name, args.x_start, args.x_stop, args.x_steps,
+            args.y_spec_name, args.y_start, args.y_stop, args.y_steps)
+
+
+def main():
+    _main(sys.argv[1:])
+
+
+def test_example():
+    options = {'simulate': True, 'driver_setup': {'Model': '6571'}, }
+    example('PXI1Slot2,PXI1Slot3', options, 'AC.Strobe', 0.0, 1e-8, 2, 'DC.Voh', 0.0, 5.0, 2)
+
+
+def test_main():
+    _main(['--x-steps', '2', '--y-steps', '2'])
+
+
+if __name__ == '__main__':
+    main()
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<SourceFile Checksum="6580C473F15E9216FD11D1EC7B291705" xmlns="http://www.ni.com/PlatformFramework">
+	<SourceModelFeatureSet>
+		<ParsableNamespace AssemblyFileVersion="5.3.1.50153" FeatureSetName="Digital Pattern Editor" Name="http://www.ni.com/PatternBasedDigital" OldestCompatibleVersion="4.5.0.0" Version="4.6.0.49152" />
+		<ParsableNamespace AssemblyFileVersion="5.3.1.50153" FeatureSetName="Editor" Name="http://www.ni.com/PlatformFramework" OldestCompatibleVersion="5.2.0.49153" Version="5.2.0.49153" />
+		<ApplicationVersionInfo Build="5.3.1.50153" Name="Digital Pattern Editor" Version="19.0.0" />
+	</SourceModelFeatureSet>
+	<Project xmlns="http://www.ni.com/PlatformFramework">
+		<ProjectSettings Id="1" ModelDefinitionType="ProjectSettings" Name="ZProjectSettings" />
+		<EmbeddedDefinitionReference Id="2" ModelDefinitionType="NationalInstruments.ProjectExplorer.Modeling.ProjectDataManager" Name="ProjectExplorer">
+			<ProjectExplorer />
+		</EmbeddedDefinitionReference>
+		<NameScopingEnvoy Id="3" ModelDefinitionType="DefaultTarget" Name="DefaultTarget">
+			<DefaultTarget />
+			<FileReference Id="14" ModelDefinitionType="PinLevelsDefinition" Name="PinLevels\.digilevels" StoragePath="PinLevels.digilevels" p4:IsActive="True" xmlns:p4="http://www.ni.com/PatternBasedDigital" />
+			<FileReference Id="15" ModelDefinitionType="SpecificationsDefinition" Name="Specifications\.specs" StoragePath="Specifications.specs" />
+			<FileReference Id="17" ModelDefinitionType="TimingDefinition" Name="Timing\.digitiming" StoragePath="Timing.digitiming" p4:IsActive="True" xmlns:p4="http://www.ni.com/PatternBasedDigital" />
+			<FileReference Id="18" ModelDefinitionType="PinMap" Name="PinMap\.pinmap" StoragePath="PinMap.pinmap" p4:IsActive="True" xmlns:p4="http://www.ni.com/PatternBasedDigital" />
+			<SourceFileReference Id="790" ModelDefinitionType="ShmooSetupDefinition" Name="Shmoo\.digishmoo" StoragePath="Shmoo.digishmoo" />
+			<EmbeddedDefinitionReference Id="799" ModelDefinitionType="{http://www.ni.com/PatternBasedDigital}CaptureResultsDefinition" Name="CaptureResults">
+				<CaptureResultsDefinition xmlns="http://www.ni.com/PatternBasedDigital" />
+			</EmbeddedDefinitionReference>
+			<EmbeddedDefinitionReference Id="801" ModelDefinitionType="{http://www.ni.com/PatternBasedDigital}BurstResultsDefinition" Name="BurstResults">
+				<BurstResultsDefinition xmlns="http://www.ni.com/PatternBasedDigital" />
+			</EmbeddedDefinitionReference>
+			<EmbeddedDefinitionReference Id="803" ModelDefinitionType="{http://www.ni.com/PatternBasedDigital}SystemInfoDefinition" Name="SystemInfo">
+				<SystemInfoDefinition xmlns="http://www.ni.com/PatternBasedDigital" />
+			</EmbeddedDefinitionReference>
+			<EmbeddedDefinitionReference Id="804" ModelDefinitionType="{http://www.ni.com/PatternBasedDigital}DigitalScopeDefinition" Name="DigitalScope">
+				<DigitalScopeDefinition xmlns="http://www.ni.com/PatternBasedDigital" />
+			</EmbeddedDefinitionReference>
+			<FileReference Id="807" ModelDefinitionType="DigitalPatternEditor.PatternDefinition" Name="demo_pattern_no_hw\.digipat" StoragePath="demo_pattern_no_hw.digipat" />
+			<FileReference Id="840" ModelDefinitionType="CaptureWaveformDefinition" Name="demo_waveform\.digicapture" StoragePath="demo_waveform.digicapture" />
+			<FileReference Id="844" ModelDefinitionType="SourceWaveformDefinition" Name="demo_src_wfm\.tdms" StoragePath="demo_src_wfm.tdms" />
+		</NameScopingEnvoy>
+		<EmbeddedDefinitionReference Id="7" ModelDefinitionType="DigitalPatternEditor.ProjectPropertiesDefinition" Name="ProjectProperties">
+			<ProjectPropertiesDefinition xmlns="http://www.ni.com/PatternBasedDigital" />
+		</EmbeddedDefinitionReference>
+	</Project>
+	<ProjectInformation xmlns="http://www.ni.com/PlatformFramework" />
+</SourceFile>
-Original file line number
+Diff line change
@@ Expand Up / @@ -558,6 +558,7 @@ @@
     #### [nidigital] Unreleased
     - Added
       - (Common) Added `nitlsconfig[grpc]>=1.0.0a2` to the optional gRPC dependencies.
+      - Added the `nidigital_unload_and_reload_specifications_file.py` example.
     - Changed
     - Removed
@@ Expand Down @@