AutoFocus User’s Guide
39
©1989-2018 Lauterbach GmbH
4. Check
TRACE32 differentiates between two views of data eyes:
•
Analog view of data eyes (check 5)
•
Digital view of data eyes: Check 4 is only about the digital view of data eyes.
Trace data is sampled at clock edges, on rising only or rising and falling. They must be stable around the
clock edge over a short time. This time window of stable data is reflected in so-called data eyes.
TRACE32 offers a powerful feature called
Analyzer.ShowFocus
to analyze the signal integrity of the trace
port.
Analyzer.ShowFocus
opens the digital
ShowFocus
window.
Analyzer.ShowFocus
is a kind of digital
view of the data eyes.
The horizontal axis reflects time line in nanoseconds. On the left, the current delay is shown for each trace
signal. The red line shows the sampling point. It can be different for each signal.
Data lines are delayed if values smaller than zero are set or not all sampling points are equal. In case of
values larger than zero, the clock line is delayed.
The horizontal axis shows all enabled signals listed. That means the number of signals depends on the
setup of the trace port. The window needs to be re-opened after the trace port setup has changed.
NOTE:
The data seen by the AutoFocus preprocessor depends highly from the clock
threshold setup. Depending on the signal integrity, the data eyes are more or
less wide open.
NOTE:
The data delay is used to eliminate data skew.
Clock delay is used to correct setup and hold times.
Both delays types can be used at the same time.