User guide

12-14
Delays and Timing
3. At time 26 the input port toggles to 0. This cancels the current
scheduled second event and replaces it by scheduling a transition
to 0 at time 36. The first scheduled event is a transition to 0 at
time 30 so the new second scheduled event isn’t really a transition
on the output port. This is how this implementation filters out
narrow pulses.
4. At time 29 the input port toggles to 1. This cancels the current
scheduled second event and replaces it by scheduling a transition
to 1 at time 39.
5. At time 30 the output port transitions to 0. The second scheduled
event on the output becomes the first scheduled event and is
therefore no longer tentative.
6. At time 39 the output port toggles to 1.
Typically, however, you will want to specify that VCS replace or reject
certain narrow pulses. Figure 12-6 shows the waveforms for the input
and output ports for an instance of the same module with a ten time
unit module path delay. The vcs command line contains the following
compile-time options:
+pulse_e/60 +pulse_r/40
Figure 12-6 Pulse Control with Inertial Delays and a Narrow Pulses