Specifications

76 Chapter 4—Simulation
NOTE: 1) It is left completely to the user to decide if the specified initial values
make sense. No checking is done to determine if a given device output
value is the reasonable result of the device’s current input.
NOTE: 2) Devices do not have initial value settings, since their values are com-
pletely determined by the state of their output pins. See the section, Pin Ini-
tial Values, below.
Signal Initial Values
An initial value for a signal can be placed in the Initial.Sig attribute field
using the format described in the previous section. When a Clear Simula-
tion operation is invoked, the initial value specified is placed on the signal
without regard for the current output levels of devices driving the signal.
The given value will stay on the signal until some device driving the signal
changes state, or some other user action changes it.
NOTE: If a pin initial value is specified for any output pin driving the signal, the
signal value will be overridden.
Pin Initial Values
The initial value for a pin is stored in the Initial.Pin attribute field, using the
format described earlier. Initial values can only be specified for output or
bidirectional pins and will be ignored on input pins.
When a Clear Simulation operation is invoked, the specified initial value is
placed on the pin without regard for the current inputs affecting the device.
The given value will stay on the pin until the device model schedules a
state change or some other user action changes it.
Schematic Simulation Issues
Working With Subcircuit Devices
The simulator does not impose any new rules on working with subcircuit
devices, but editing a design with active simulation has some effects that
should be noted.
LW Reference.bk Page 76 Monday, December 15, 2003 5:59 PM