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Chapter 1: Agilent Technologies 16712A 128K Sample Logic Analyzer
The Trigger Tab
Context Store Measurements (State Only)
In a measurement that uses
context store
, the analyzer captures the
events you specify in the trigger sequence, and places the events in the
center of a
context record
. The context record shows the states that
preceded and followed the event. The
data set
then contains a series of
records.
A typical use of a context store measurement is to capture a series of
writes to a variable or calls to a subroutine.
Context store is only available when the analyzer is in
state
mode.
1. Set up a
trigger sequence
.
Each
Find
,
Else On
, and
Trigger
event that occurs will get a context
record.
2. To show only the context around the events and no other states, make sure
each level is set to
Store no state
.
3. Select the
Settings
tab, then
Context Store
and select the desired size of
the context records (16, 32, or 64 states).
The context record may be smaller than the size you set if events overlap.
4. Select the qualifier for the states to be stored before and after the event.
For all states around the event, select
anystate
.
5. Select the Run button.
NOTE:
To extend the context record, filter out states that you are not interested in
such as no-ops. Set a
pattern term
to match no-op, then qualify the context
store with
Not patterns
. The excluded patterns will not be included in the
context store count.
Context Store Measurement Example
Assume you need to see which routines are writing to a variable. You
set up a trigger sequence that stores the writes to the variable. Then
you set Context Store to 64 states and context storage to "anystate".
Then select the Run button.
Every time the analyzer sees a write to the variable, it captures the
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