To test minimum and maximum pulse limits
1 Select the timing analyzer Trigger menu.
2 Define the Edge1 term to represent the positive-going transition, and
define the Edge2 term to represent the negative-going transition on
the line with the pulse to be tested.
You can rename these terms to POS_EDGE and NEG_EDGE.
3
Define the Timer1 term to represent the minimum pulse width, and
the Timer2 term to represent the maximum pulse width.
You can rename these terms to MIN_WID and MAX_WID. In this example,
Timer1 was set to 496 ns and Timer2 was set to 1 µs. Both timers start when
sequence level 2 is active.
4
Under Timing Sequence Levels, enter the following sequence
specification:
•
Find “POS_EDGE” 1 time
•
Then find “NEG_EDGE” 1 time
•
TRIGGER on “MIN_WID 496 ns + MAX_WID 1.00 µs” 1 time Else on
“anystate” go to level 1
Because both timers start when entering sequence level 2, they start as soon
as the positive edge of the pulse occurs. Once the negative edge occurs, the
sequencer transitions to level 3. If at that point, the MIN_WID timer is less
than 496 ns or the MAX_WID timer is greater than 1 µs, the pulse width has
been violated and the analyzer should trigger. Otherwise, the sequence is
restarted.
Measurement of Minimum and Maximum Pulse Width Limits
Triggering
To test minimum and maximum pulse limits
1–18
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