Conveyor belt analogy, 241 | Agilent Technologies 16760A instruction

Chapter 6: Concepts

Understanding Logic Analyzer Triggering

placed on the conveyor belt, and at the other end the boxes fall off. In other words, because logic analyzer memory is limited in depth (number of samples), whenever a new sample is acquired the oldest sample currently in memory is thrown away if the memory is full. This is shown in the following figure.

The conveyor belt analogy

A logic analyzer trigger is similar to someone standing at the beginning of the conveyor belt placing more boxes on it. They are told to “look for a special box and to stop the conveyor belt when that box reaches a particular position on the belt”. Using this analogy, the special box is the trigger. Once a logic analyzer detects a sample that matches the trigger condition, this is the indication that it should stop acquiring more samples when the trigger is located appropriately in memory.

The location of the trigger in memory is known as the trigger position. Normally, the trigger position is set to the middle so that the maximum number of samples that occurred before and after the trigger are in memory. However, you can set the trigger position to any point in memory.

The concepts in this analogy are summed up in the following table.

Mapping of concepts in the Conveyor Belt Analogy to a Logic Analyzer

Conveyor	Belt Analogy	Logic analyzer
=====================		==============================
Boxes on	the belt	Samples acquired from the
		device under test
---------------------		------------------------------
Number of boxes that		Memory depth
will fit	on the belt	------------------------------
---------------------		------------------------------

241

Image 241

Agilent Technologies 16760A manual Conveyor belt analogy, 241

Contents

Agilent Technologies. All rights reserved Agilent Technologies 16760A Logic Analyzer Sampling Mode on Captures input signals as low as 200 mV p-pAgilent Technologies 16760A Logic Analyzer Probing Concepts on Reference on Glossary see See Also Contents Choosing the Sampling Mode 110 Using Symbols 101112 114 152 Displaying Captured Eye Scan Data155 Format Tab 174 210 Eye Scan Tab 204211 240 Specifications and Characteristics259 Glossary Index Contents Getting Started Eye scan sampling mode, measurements will have these steps Next . Choose the sampling mode on Probing and Sampling Mode Selection StepsConnect logic analyzer to the device under test To choose the sampling mode Choose the sampling mode If you chose State Mode If you chose Timing Mode Either Timing Mode or State Mode Next . Format labels for the probed signals onIf you chose Eye Scan Mode Format labels for the probed signals To specify threshold voltages To assign pods to the logic analyzer Defined threshold voltage Select the Close button NextTo assign names to logic analyzer channels Define the trigger condition Timing Mode or State Mode Steps Next . Run the measurement on Run the measurement Next . Display the captured data on Display the captured dataTo open Waveform or Listing displays To add display tools via the Workspace window Next For More Information... on Select channels for the eye scan measurement Eye Scan Mode Steps Next . Set the eye scan range and resolution on Set the eye scan range and resolution Next . Run the eye scan measurement on Run the eye scan measurement Next . Display the captured eye scan data on Display the captured eye scan data Eye Scan display window, use the following subtabs For More Information For More Information Probing and Selecting the Sampling Mode Probing and Selecting the Sampling Mode Probing the Device Under Test Using the E5378A Single-Ended Probe Number Single-ended signalNumbers Either Using the E5379A Differential Probe Independent threshold adjustment Or single-ended signalsNegative data inputs Reference voltage Or AMP Using the E5380A Mictor-Compatible Probe Using the E5382A Single-ended Flying Lead Probe Set Additional Accessories Using an Analysis Probe Probing the Device Under Test Selecting the Timing Mode Asynchronous Sampling Choosing the Sampling Mode To select the conventional/transitional configuration To select the timing mode Sample rate is the inverse of the sample period To specify the sample period State Mode Sampling Position Selecting the State Mode Synchronous SamplingTo automatically adjust sampling positions on To manually adjust sampling positions on To select the state speed configuration To select the state mode For the clock input signal that will be used To set up the sampling clock Automatically sets the sampling position To automatically adjust sampling positionsRun simultaneously To run eye finder repetitively Choose the labels that you wish to run eye finder on To view eye finder data as a stack of channels To view eye finder data as a bus compositeTo save/load eye finder data Eye Finder Advanced Settings Dialog on To manually adjust sampling positionsEye finder data must be saved and loaded separately To specify the trigger position Either Timing Mode or State ModeTo set acquisition memory depth To turn an analyzer off or on To name an analyzerYou can give more descriptive names to a logic analyzer You can also name analyzers in the Pod Assignment Dialog on To select the eye scan mode Selecting the Eye Scan ModeTo select the eye scan mode speed configuration High-speed or high-bandwidth oscilloscope To set up the eye scan mode reference clock Formatting Labels for Logic Analyzer Probes Format tab has activity indicators that show signal levelsTo assign pods to the analyzer To set up qualified eye scan measurements on Capturing Data on 17 Channels in State ModeTo set pod threshold voltages To set clock threshold voltages To assign probe channels to labels Label off Maximum of 32 channels can be assigned to a labelTo delete labels To import label names and assignments from a netlist SignalsE5378A and E5380A probe types to be selectable Label To assign label name Blue to channel 5 on pod A2 To import label definitions from an Ascii fileLabel Definition File Format Examples To change the label polarity To export label definitions to an Ascii fileChannel 5 on pod A2, and channel 6 on pod A1 Changing the label polarity will have the following effects To reorder bits in a labelChanging the label polarity does not affect To turn a label off To turn labels off or onTo turn a label on To display a label that was off Using the Logic Analyzer in Timing or State Mode Using the Logic Analyzer in Timing or State Mode Use trigger functions for basic measurements Setting Up Triggers and Running MeasurementsGeneral To select a trigger function Using Trigger Functions To specify a label pattern event Timing only To specify a label edge event To enter symbolic label values on Symbols Selector Dialog on To compress a trigger function To expand a trigger function To copy trigger function libraries between systems To load/unload trigger function libraries To count time, states, or turn counting off Using Other Trigger Features To assign pods to the analyzer on To specify default storingReduced by half in order to store the required time tags If you chose Custom To clear default storing changes Trigger tabs Default Storing subtab, select the At start Default storing is initially on or offTo insert a store action state mode on Acquisition option button and choose either On or Off To clear the trigger sequence on To insert/replace/delete sequence levelsTo insert sequence levels To replace sequence levels To cut/copy-and-paste sequence levels Setting Up Triggers and Running Measurements Example system14 Slot C Analyzer C has triggered To view a picture of the trigger sequence To restore default trigger settingsTo clear the trigger sequence Trigger tab, select the Overview subtab To specify a time duration for events timing only To specify a duration or occurrence count for events To insert timer actions/events To insert a store action state modeTo insert a timer action Available To insert counter actions/events To insert a timer eventTo insert a counter action To insert a counter event To insert flag actions/events To insert a flag event To drive the Port Out signal with a flag To group events To insert a reset occurrence counter actionTo use named events To save a trigger setup Saving/Recalling Trigger SetupsTo give an event list a name To insert a named event Running Measurements To recall a trigger setupTo clear the trigger save/recall list To start/stop measurements To stop a measurement If nothing happens when you start a measurementSelect the Stop or Stop All button Waiting for Trigger on To view the trigger status To open Waveform or Listing displays Displaying Captured Data To use other display tools Help volumeWindows Search for particular data values captured on labels Displaying Captured Data Intermittent Data Errors Unwanted Triggers Analyzer help volumeIf the captured data doesnt look correct Into parallel words which are easier to view and analyze This situation will occur in these cases If there are filtered data holes in display memory To view symbolic values in a waveform display To display symbols for data valuesTo view symbolic values in a listing display Select the Cancel button To cancel the display processing of captured data100 You can use symbol names in place of data values when Using Symbols101 To reload object file symbols To load object file symbols102 Object file symbols are reloaded To adjust symbol values for relocated code Whose symbols you wish to relocate To create user-defined symbolsTo replace user-defined symbols 104 When entering label values in the trigger sequence To enter symbolic label valuesTo delete user-defined symbols To load user-defined symbols General-Purpose Ascii GPA Symbol File Format on To create an Ascii symbol file106 Create the reader.ini file on your workstation or PC ReadOnlyTicoffPage StabsTypeAppendTicoffPage Examples Example for Elf/Stabs Example for Ticoff Example for Coff/Stabs using Ticoff reader109 You can print captured data from display tool windows Printing/Exporting Captured Data Select the Read File button Select the file name and automatic file sequencing optionsIcon to view the imported data 111 To cross-trigger with another instrument Cross-Triggering112 113 When the logic analyzer drives the arm signal To test the logic analyzer hardware Solving Logic Analysis ProblemsTo test the logic analyzer hardware on 114 System help volume Service Center for assistance115 To save logic analyzer configurations Saving and Loading Logic Analyzer ConfigurationsTo load logic analyzer configurations 116 117 Using the Logic Analyzer in Eye Scan Mode 118 Eye Scan tab lets you set up and run Eye Scan measurements Setting Up and Running Eye Scan MeasurementsTo select channels for the eye scan 119 Scan Settings Subtab on To set the eye scan range and resolution120 To run an eye scan measurement To quickly set up another measurement using the scale seeTo set advanced eye scan options 121 Advanced Subtab on To set up qualified eye scan measurements122 Memory device versus a memory controller Requirements Signal Timing Burst Transfers123 Burst Has adjustable sampling positions on each input channelAfter the rising edge of the clock Before the clock edge to after it Are supported Clock cycle of the next burst125 126 127 Be sure that the thresholds are set correctly Not already expanded For correct state mode acquisitionsStart your target system and select Run Eye Finder Display 129 Now, set up eye scan mode 130 Select the Eye Scan tab Select the Qualifier subtab 131 Select the Qualify eye scan sampling using... button To comment on the eye scan settings To open the Eye Scan display Displaying Captured Eye Scan Data133 Tool To select the channels displayedWithin the data captured on the bus 134 Scale tab, you can To scale the Eye Scan displayTo use the scaling options Eye Scan display window, select the Scale tab To set Eye Scan display options To quickly set up another measurement using the scaleTo clear the captured eye scan data To open the Eye Scan display on 137 138 139 140 To change the Eye Scan color scale Make measurements on the eye scan data on Is zero by default141 About the captured measurement data To make measurements on the eye scan data142 143 144 145 146 147 148 Scroll bars to navigate through the information To display information about the eye scan dataEye Scan display window, select the Info tab 149 150 Info tab, you can 151 To comment on the eye scan data Saving and Loading Captured Eye Scan Data Loading Logic Analyzer Configurations on152 153 Sampling Tab on Format Tab on Trigger Tab on 154 Sampling tab lets you choose between the logic analyzers Sampling Tab155 Conventional Transitional Timing ModeAcquisition 156 Will be stored How Samples are Stored in Transitional TimingPeriod and other times more than two sample periods apart Samples with transitions State Speed State Mode158 159 Sampling Positions Dialog File menu Lets you save/load eye finder data Sampling Positions Tab160 Display Area Label buttonsSampling Position 161 How the Suggested Position Behaves How the Selected Position BehavesXX% complete Cannot run the Eye Finder at this time Characterizer cannot be loaded Cannot run the Logic Analyzer at this timeComplete Date 163 Select one or more labels in the Eye Finder Setup tab This channel appears to be completely quiet Timeout N K clocks in 5 secTwo common possibilities exist 165 See individual channels for messages Run Eye Finder to characterize this channelStable region extends beyond the limits of the display 166 Disk is probably full Numerical value for the item XXX could not be read File Name already exists. Overwrite? Failed to open file for reading/writing NameInvalid true/false flag Unsupported revision level AA.BB 169 Eye Finder Setup Tab 170 Eye Finder Advanced Settings Dialog 171 File Info Tab Reload Eye Scan ModeSave Save As 173 Selecting the Eye Scan Mode on Format Tab Expander cards which cannot be used in the clock setupData Specify the logic analyzer pod and clock threshold voltages Name Pod Assignment DialogType Pods 176 Trigger Tab 177 Trigger Functions Subtab 178 General Timing Trigger Functions 179 180 General State Trigger Functions 181 Find pattern1 eventually followed by pattern2 182 183 Advanced Trigger Functions 184 State Trigger Functions Turbo State Trigger FunctionsAdvanced pattern1 or pattern2 Searched for 186 187 Half Channel State Trigger Functions Count Settings SubtabIntermodule Control 188 This tab gives a picture of the trigger sequence Overview Subtab189 Event Specification List Default Storing SubtabAt start Acquisition Group events Save/Recall Subtab Status Subtab191 192 Creating trigger function libraries Two kinds of symbols are available Symbols TabThat you use to set up resource terms Multiple files 194 Object file versions See Also Matching Symbols Symbols Selector Dialog195 Offset By Option Search PatternAddress masking is done by the Align to x Byte option Align to x Byte Option Symbol File FormatsByte option allows you to mask off an address Qualifies any address from 100C through 100F 107 file General-Purpose Ascii GPA Symbol File Format198 Format GPA Record Format Summary199 Definitions in the file Records200 Symbol representing the function name Symbol representing the name of the sectionFirst address of the section, in hexadecimal Last address of the section, in hexadecimal Name of a file You can specify symbols for variables usingNumber of a line in the file, in decimal 202 203 Comments Labels Subtab Eye Scan TabExpand Collapse Shows labels only Select All Selects all channels Run Mode Scan Settings SubtabScan Range Time 206 Advanced Subtab Medium ShortLong Custom Qualification Qualifier SubtabClock Edge to Sample Names for 209 Comments Subtab Calibration Instructions Calibration TabCalibration Status Calibration Messages 211 Error Messages General Guidelines Branch expression is too complex212 213 Specific Guidelines 200 Mb/s State and all Timing Modes This one may If the following sequence does not compileSpecific Guidelines 400 Mb/s State Modes 214 215 Specific Guidelines 1250/1500 Mb/s State Mode Specific Guidelines 800 Mb/s State Mode216 217 Hardware Initialization Failed Goto action specifies an undefined levelPossible Causes Last sequence level calls goto next Must assign another pod pair to specify actions for flags Maximum of 32 Channels Per LabelNo more Edge/Glitch resources available for this pod pair Timing sampling mode, flags are are always available No more Pattern resources available for this pod pair Possible SolutionsPhrase some of the edges as patterns 220 Slow or Missing Clock No Trigger action found in the trace specification221 222 Trigger function initialization failure Trigger Specification is too complex Trigger inhibited during timing prestoreThen the approximate time is 32 seconds 223 Event Combiner resource allocation guidelines224 Misaligned boundaries for addresses Waiting for Trigger225 226 To save a trigger setup on Operating temperature 0 to 45 degrees C Specifications and CharacteristicsProbes 227 E5379A Differential Probe Specifications Characteristics E5378A Single-Ended Probe Specifications CharacteristicsAll specifications are marked by * asterisk E5378A Input Equivalent Circuit 229 E5379A Input Equivalent Circuit E5380A Input Equivalent Circuit 1500 Mb/s Sampling Mode Specifications and Characteristics230 231 Characteristics 232 233 400 Mb/s Sampling Mode Specifications Characteristics 234 200 Mb/s Sampling Mode Specifications Characteristics Transitional Timing Mode Specifications and Characteristics Conventional Timing Mode Specifications and CharacteristicsAll specifications are marked by * asterisk 235 236 What is a Specification? What is a Function Test? What is a Characteristic?Referred to as an operational accuracy calibration 237 238 239 Concepts Conveyor Belt Analogy Understanding Logic Analyzer Triggering240 241 Conveyor belt analogy Sequence Levels Summary of Triggering CapabilitiesNext Summary of Triggering Capabilities on Next Sequence Levels on 243 Addr Data 244 Boolean Expressions Edges BranchesRanges Next Ranges on Occurrence Counters and Global Counters FlagsNext Flags on Trigger Sequence for Module Next Timers on TimersAn example trigger sequence to set up this measurement is An edge followed by an edge with a time limit Storage Qualification Default StorageNext Storage Qualification on Needed 250 Sequence Level Storage Next Strategies for Setting Up Triggers on Strategies for Setting Up TriggersTrigger Functions 251 Pattern2 occurring immediately after Pattern1 Agilent 16715A trigger user interface252 Store range until pattern occurs Same trigger as If/Then statements253 Next Setting Up Complex Triggers on Setting Up Complex TriggersDocument Your Trigger Sequences Next Document Your Trigger Sequences on Different parts of the trigger to describe how they work ConclusionsNext Conclusions on Inline documentation on an Agilent logic analyzer To accurately capture data on a bus Understanding State Mode Sampling Positions256 257 258 Window 259 Understanding Eye Scan Measurements 260 261 Using the Logic Analyzer in Eye Scan Mode on Voltage resolution that can be set is 1 mVAre multiple logic analyzer cards in a module in this case Measurements run simultaneously in parallel Asterisk * See edge terms, glitch, and labels Glossary263 264 Divided into 1K 64-state records 265 Debug mode See monitor 266 Ethernet address See link-level 267 268 269 Module/probe interconnect cable Processor probe See emulation By the channel width of the instrument270 271 Measurements 272 273 274 275 Index 251 276 247 277 122 278 180 279 280 Label values, symbolic, 105 labels, 22 Positive logic 281 242 282 107 283 Wait for other machine to trigger 284 Publication Number 5988-9044EN January 1