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Chapter 1: Agilent Technologies 16712A 128K Sample Logic Analyzer
The Trigger Tab
approximately as many samples before the trigger as after. You can also
arrange for the trigger to be at the beginning of the "conveyor belt"
(acquisition memory), the end, or any percentage along it.
What can be Used to Specify a Trigger
The trigger sequence can be as simple as one event to look for, or a
complicated set of branching levels that loop back and jump around.
Both types of triggers use a small set of standard resources.
Pattern
Pattern terms are things such as
ADDR=0880
or
R/W=1
.
Generally they represent values on buses. You can set patterns to
match imprecise events, too. See “Using Bit Pattern Terms” on page 93.
Range
Range terms match a range of values on a label or bus. For more
detail, see “Using Range Terms” on page 94
Timer
Timers are started in one sequence level and checked in another.
They act like stopwatches. See “Using Timer Terms” on page 96 for
more information.
Edge
Edge terms are similar to edges in oscilloscopes. They are only
available for some types of measurements. Edge terms can check for
edges on more than one signal at a time, but not all edges have to occur
at the same time. To require that, combine edge terms with
AND
s.
Combinations of Terms
To check for more than one type of thing
happening
in the same sample
, combine terms within a sequence
level using
AND
and
OR
. There are restrictions on exactly which terms
can be ANDed and which ORed. The restrictions are covered in “Using
Combinations of Terms” on page 97.
When to use a Combination, a Branch, or a Level
To check for simultaneous occurrences, use combinations of terms. All
the events described by the terms must happen in the same sample.
To take different actions depending on which events happen in a
sample, use
branches
within a sequence level. A branch functions like
a set of "if statements" in programming. The sample is checked against
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