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I
Example
The Trigger Menu
Modifying the User-level Macro
The number of User-level macros you
will
use, or what you assign to the
resource terms is difficult to predict because of the variety of applications. A
general approach is to think of each field assignment or each new sequence
level as an opportunity to lead the analyzer through key points in the data
stream. Your end result is to select the desired point in the data to trigger
on, and to store only the data you want.
If
you know the data structure and
flow well enough, you could build a flowchart.
A typical method used during a debug operation is to first trigger on a known
pattern, edge or range. From that point, it becomes an iterative process of
adding more levels to further filter the data. It is important for you to know
how to use such elements as occurrence counters, timers, and branching, to
zero in and trigger at the desired point.
As the analyzer executes the trigger specification, it searches for a match
between the resource term value and the data. When a match is found, that
part of the sequence statement becomes true and the sequencing continues
to the next part of the statement or the next sequence level.
Eventually a path of "true" resource terms leads to your trigger command.
If
timers or occurrence counters are used, the analyzer waits or counts
occurrences of a specified value before continuing.
The following examples illustrate the use of resource terms, occurrence
counters, timers, branching, and store qualification. You
will
use them in
your trigger specification either by themselves or in combination with each
other.
Using Bit Patterns, Ranges, and Edges
Bit patterns are set to match specific data values, and ranges are set to match
a range of bit patterns. In the
Timing
Acquisition mode, edges are set to
match specific edges of a timing pulse.
The following statement looks for the bit pattern you assigned to term "a" to
occur
11
1
11
time, before it triggers.
TRIGGER on (.._ _ _ _ _ _ _ _ a _ _ _ _ _ _ _ _....) Occurs (.._ _ _ _
_,J
5-20
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