Agilent Technologies FS2334 user manual TimingZoom Analysis, Decoding DDR Commands

TimingZoom Analysis

The TimingZoom feature of the 1690x logic analyzer allows for efficient timing analysis of all the signals on the DDR2 DIMM bus.

Please refer to the “Setting up the 16900 Analyzer” section of this manual on the use of the general purpose probe feature to determine how to attach the logic analyzer to the probe.

Load the logic analyzer configuration file for timing, FS234_2. It doesn't matter whether you select to load "Configs only" or "Configs and Data". You are now ready to start making measurements.

For timing analysis operation above 600 MHz you need to use the ½ Channel Timing Mode, which provides bandwidth to 1.2GHz. This mode makes every other pod available to the user so 4 cards are required. These must be configured via the cables supplied with the cards as a single logic analyzer module. Refer to the appropriate Agilent Technologies manual for information on how to connect analyzer cards together to create multi-card modules.

Please note that 6 of the ECC bits and their Data Strobe (DQS8) are contained on an extra Header (#14), which will require an additional logic analyzer card in order to probe.

Decoding DDR Commands

No Protocol Decoder is used for timing analysis. However, symbols are pre-defined for the DDR2 Command bus. These decode the RAS, CAS, and WE lines to display the DDR Command as “Read”, “Write”, etc., so you don’t have to refer to the DDR chip data sheet to see what command is being executed. These decoded values are displayed by setting the display base (in the listing window) or the label property (in the waveform window) to “Symbols”. The display base defaults to hexadecimal.

Taking a Trace, Triggering, and Seeing Measurement Results

Timing analysis is the simplest setup and there are no special factors involved in analyzer trigger setup, initiating a trace, and viewing results. For the Command bus you can use the pre-defined symbols to specify mnemonically the command you wish to trigger on. These are set up by default and are accessible in the trigger tab. The default waveform display also shows DDR Commands mnemonically.

You may setup a trigger, initiate a measurement, and view results in the usual ways via the trigger tab, pressing the Run button, and opening the desired display window.

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