Agilent Technologies FS2331 user manual Inverse Assembler and Decoding DDR Commands

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3.Trigger the analyzer on any burst.

4.Open a new All Waves waveform window that displays measurement results from both the Command and Data analyzers. This can be done from the Workspace window by dragging a waveform display tool onto the Workspace and connecting the output of each Data and Command analyzer to the tool.

5.Insert the labels DATA_TZ:BUFFCMDCLK_TZ and COMMAND_TZ:BUFFCMDCLK_TZ onto the waveform window.

6.Find corresponding edges of both labels and note the time difference between them as displayed in the waveform window. You may need to set the display scale to less than 5ns/division to do this properly. You can do this very accurately by placing the G1 marker on one edge and the G2 marker on the corresponding edge of the other label. The time difference between the markers will be displayed in a small popup window for about 5 seconds.

7.Open the "Intermodule Skew..." dialog of the "Window->System->Intermodule..." window and modify the entry corresponding to the Data analyzer as follows:

If DATA_TZ:BUFFCMDCLK_TZ edges are after (before)

COMMAND_TZ:BUFFCMDCLK_TZ then add (subtract) the time difference displayed in the waveform to the current skew value and enter the new value.

8.Press the "Apply" button. The waveform display will be updated and should show the DATA_TZ:BUFFCMDCLK_TZ and COMMAND_TZ:BUFFCMDCLK_TZ signals occurring within 1ns of each other. You may go back to step 8 if you wish, repeating as necessary to find the correct Intermodule skew adjustment value.

If you save the analyzer configuration for all modules then the skew adjustment will be saved as well. This calibration may need to be repeated from time to time to ensure that the skew remains minimized.

The Inverse Assembler and Decoding DDR Commands

The inverse assembler has an optional feature that will match a read or write command with its corresponding ACTIVATE command for the same bank and DIMM, and display a complete row/column address for the read or write command. The ADDR_B label is used for this purpose, and has been defined on the same logic analyzer channels as the Chip Select and Bank Address labels so that it can know which DIMM is being issued a given READ, WRITE, or ACTIVATE command. This feature may be turned on and off in the dialog that is displayed by selecting the “Invasm/Preferences” menu pick. When it is turned off the inverse assembler will display only the column and bank address passed to the READ or WRITE Command (as well as the Command itself).

Symbols are pre-defined for the DDR Command bus. These decode the RAS, CAS,

and WE lines to display the DDR command as “Read”, “Write”, “Precharge”, etc., so you don’t have to refer to the DDR chip data sheet to see what command is being executed. Symbols have also been pre-defined for the read/write status generated by the probe.

Taking a Trace, Triggering, and Seeing Measurement Results

For state analysis measurements both the DDR Command and Data busses are captured, each by a separate logic analyzer module. The 167xx and 169xx Intermodule Bus is used to communicate triggering information between the modules. The default analyzer configurations shipped with the FS2331 for state measurements pre-configures a trigger in which a specified Command is detected and causes a trigger of the

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Contents Revision DDR Sdram Analysis Probe FS2331How to reach us Product Warranty Signal Connections For Sales and Marketing Support For Technical SupportProduct Warranty Limitation of warrantyExclusive Remedies Logic Analyzer Modules Probe Cable, Connector NumberingIntroduction DefinitionsFS2331 100 pin Connector to Pod Diagram Probe Feature Summary FS2331 Probe DescriptionProbe Components DDR Data DDR CommandsProbe Design State Clock GenerationPage Pod Clock Domain Clock Rate Probe Pod AssignmentSwitch # Default factory Function Position Probe Switch SettingsOn closed Logic Analyzer Signal Threshold Voltage Settings Connecting the Probe to the Logic AnalyzerConnecting Power to the FS2331 Probe Card Requirements for PC2700 Systems Logic Analyzer Card Requirements 16753/4/5/6Recommended 169xx Licensing Setting up the 167xx AnalyzerSetting up the 169xx Analyzer Software Requirements System SoftwareTiming Analysis All DDR speeds and supported analyzer cards Card Configurations for State Analysis Probing multiple DDR busses Interleaved memory If User is dedicating a Connecting to your Target System Chip Select§ Isolate the Dedicated DIMM’s pin Chip Select Jumper locations§ Sleeve the Pin Unused Pods § Wire from the adjacent Dimm slot to the isolated pin Offline Analysis Filtering Taking a Trace, Triggering, and Seeing Measurement Results Loading the Inverse Assembler and Decoding DDR CommandsTiming Analysis Operation State Analysis OperationInverse Assembler and Decoding DDR Commands Tracing the Serial Presence Detect Signals Using Eye Finder with the FS2331 DDR Probe Using EyeScan with the FS2331 Probe Dimm Signal Loading Option Using the FS2331 DDR Probe with an Interposer FS1024/25FS2331 Calibration Page Set Command sample position Page Page Write Burst Data Valid Position Page Page Page Read Burst Data Valid Position Page Page Page Set the final analyzer sample position Adjust the delay line value to maximize R/W overlapPage Standards supported General InformationSamtec Signal Connections J1 DataSA0 CB4 J2 Data and CommandSpare J3 Command and Data Buffcmdclk DM5DQS14 J4 DataDQS7
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