Specifications

74 Chapter 4—Simulation
Simulation Clearing and Initialization
The LogicWorks simulator provides a number of mechanisms to assist in
setting initial values and resetting a simulation.
The Clear Simulation Operation
You can invoke the Clear Simulation operation by clicking on the Reset
button ( in the Simulator toolbar.
This operation performs the following steps:
 Other tools (such as Timing) are notified and perform their own
processing.
 All signal–change events on the queue are disposed of, whether
pending or historical.
 Any clocks in the design are re-initialized.
 If any signal or pin initial values are specified, they are set up. See
below for information on setting initial values.
 All devices are queued for immediate re-evaluation.
The Clear Unknowns Operation
The Clear Unknowns operation is a heuristic procedure which attempts to
remove Don’t Know signal values from a design. This can be used to find
an initial state when a design is first simulated, or after any edit operations
that result in unknown values.
You can invoke this operation by clicking on the Clear Unknowns ( )
button in the Simulator toolbar.
The Clear Unknowns operation performs the following steps, stopping as
soon as all unknown states are removed from the design:
 Any pending signal change that would result in an unknown state is
removed from the queue.
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