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Chapter 4: Using the Logic Analyzer in Eye Scan Mode
Setting Up and Running Eye Scan Measurements
1. In the Eye Scan tab, select the Advanced subtab.
Select Quick Scan for a relatively fast Eye Scan.
Select Complete Scan if you are concerned about capturing noise and
signal anomolies that lie outside the area of the most regular signal activity.
Complete Scan will take significantly longer than Quick Scan.
2. Select the number of clocks to be processed at each scan point option.
You can select Short when there are frequent transitions on all channels,
Medium when the channels transition at a normal rate, or Long when
there are sporadic transitions on some of the channels.
The Custom option lets you enter the number of clock s to be processed at
each scan point.
3. Select whether results should be accumulated from scan to scan or
whether they should replace the previously scanned data.
See Also “To run an eye scan measurement” on page121
“Advanced Subtab” on page 206
To set up qualified eye scan measurements
A bus may have different signal timing requirements based on some
condition. For example, a bi-directional bus may have different timing
requirements for read transfers versus write transfers.
Eye scan can be configured to use a qualifier signal to tell it when to
collect data and when to stop collecting data.
For example: a read/write qualifier signal in a DDR (Double Data Rate)
system could be used so that data is collected only on read cycles or
only on write cycles.
Other situations in which a qualified eye scan may be necessary:
• Signal timing for reads is different than for writes.
• Different signal sources are used for reads than for writes. For example, a