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Foundation F1.3/F1.4 Simulator: Selective preset feature may disrupt theoperation of counters, state machines


Record #3124

Product Family:  Software

Product Line:  Aldec

Problem Title:
Foundation F1.3/F1.4 Simulator: Selective preset feature may disrupt
theoperation of counters, state machines



Problem Description:
Keywords: selective preset, simulate, simulator, counter

Urgency: Standard

General Description:
Executing a Selective preset feature occasionally disrupts the
functionality of state machines, such as counters.

After assigning D inputs of the counter flip-flops to some
value (i.e. ff) using this feature, execute a preset, and step.
Then, the counter either gets stuck at the preset value or
starts counting incorrectly.
This happens to feedback-looped flip-flops (such as counters).


Solution 1:

For selective preset functionality, follow these steps instead.

1. Use Signal->Add Signals to select all D pins of flip-flops
that you want to set the preset value to:
 a. To select a flip flop pin, navigate the design hierarchy
    displayed on the right hand side of the Component Selection
    window.
 b. When the desired flip flop is listed in the center pane,
    double-click on it to bring up a list of pins for this
    flip flop on the right side.
 c. Now, double-click on the D input pin to add it to the
    Waveform Viewer.
2. Use Signal->Add Stimulators to assign stimulus (preset
values) to all of these D inputs.
3. Step the simulation once.
4. Disable the stimulators by selecting the signal and clicking
on the DS button in the Stimulator Selection window.
5. Now keep stepping the simulation.



End of Record #3124