Specifications

Gates and Buffers 105
Making Non–Inverting Buffers
The Buffer primitive type can also be used to make a non–inverting
buffer—that is, a buffer with its outputs always enabled—simply by omit-
ting the enable input.
This can be used for the following purposes:
 To represent a non–inverting buffer or level translator in a design.
 To insert a delay in a signal path without affecting the logic of the
signal.
 To create various types of open collector, open emitter, or inverting
buffers, when used in conjunction with different pin type and inversion
settings on the outputs.
NOTE: It is more efficient to use the NOT primitive type to make a simple inverter.
Resistor
The resistor device simulates the effects of a resistor in a digital circuit. It is
more general than the Pullup Resistor device and can be used as a pullup,
pulldown, or series resistor. Whenever a signal–level change occurs on
either pin of the resistor, the device converts that level into a resistive drive
level (see Chapter 7, Simulation, for more information on drive levels). A
high impedance drive on one end is transmitted as a high impedance output
to the other end. Note that LogicWorks does not simulate analog properties
of devices, so the resistor device does not have a resistance value in the
analog sense and will not interact with capacitor symbols placed on the
same line. The effect of resistance on line delay can be simulated by setting
the delay of the resistor device.
LW Reference.bk Page 105 Monday, December 15, 2003 5:59 PM