FastScan and FlexTest Reference Manual, V8.6_4
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Set Xclock Handling Command Dictionary
Set Xclock Handling
Tools Supported: FastScan
Scope: All modes
Usage
SET XCLock Handling Retain | X
Description
Specifies whether FastScan changes the sequential element model to always set
the output of the element to be X when any of its clock inputs become X.
Upon invocation, FastScan uses the default flip-flop and latch models for
sequential elements. These default models retain their output values when their
clock value becomes X, so long as the other input values do not cause the stored
output value to change, regardless of whether the clock was at a 0 or 1. The Set
Xclock Handling command allows you to override this behavior during parallel
pattern simulation, thereby causing the stored output value to become X.
This command will have no effect during DRC simulation. FastScan uses the
default flip-flop and latch behavior during DRC simulation.
Arguments
•Retain
A required literal specifying that FastScan use the default sequential element
model. This is the default upon FastScan invocation.
•X
A required literal specifying that FastScan change the sequential element
model so that during parallel pattern simulation the output of the element is set
to X when any of its clock inputs become X.