Answers Database
Foundation F1.5: Simulation of HDL tutorials (Stopwatch) requires manually toggling Global Reset
Record #4557
Product Family: Software
Product Line: Aldec
Product Part: Foundation Simulator
Problem Title:
Foundation F1.5: Simulation of HDL tutorials (Stopwatch) requires manually toggling Global
Reset
Problem Description:
Urgency: Hot
General Description:
A problem exists in the Foundation Simulator that shows itself in the HDL
Tutorial found in the Foundation QuickStart Guide. The problem is this:
If the STARTUP module has been instantiated (not inferred) in an HDL design and
a separate local reset exists in the design, then the Simulator's call to the
Global Reset will not affect the flip flops using the local reset. These flip
flops will produce an X on their output as soon as their reset is released
because their GSR pin is undefined.
The Watch design has a GSR signal (GSRT) as well as an internally generated
local reset (RSTINT), so this problem is seen when the local reset is released.
This issue has been resolved and does not appear in the Foundation F2.1i tutorial.
Solution 1:
The solution is to manually toggle the signal connected to the GSR pin of the
STARTUP module. In the Watch tutorial, this can be done within the Script
Editor. After completing the Script Wizard section of the tutorial, open the
script in the Script Editor. Before the "cycle 400" line of the script enter
these three lines:
h GSRT
sim
l GSRT
This will pulse the GSRT signal and reset all the flip flops. The GSR pin on
all the flip flops will be defined and the simulation will proceed correctly.
End of Record #4557 - Last Modified: 07/30/99 08:28 |
