ECE380 Digital Logic
Number Representation and
Arithmetic Circuits:
Other Number Representations
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 20-1
Other number representations
Previously, we dealt with binary integers
(signed or unsigned)
ECE380 Digital Logic
Implementation Technology:
Buffers, Tri-state gates,
Transmission gates
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 12-1
Buffers
In circuits where a logic gate has to drive a
large capacitive load, buffers are often u
ECE380 Digital Logic
Implementation Technology:
NMOS and PMOS Transistors,
CMOS logic gates
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 13-1
Logic values as voltage levels
Vss is the minimum
voltage that can exist
in the system. We
will u
ECE380 Digital Logic
Introduction to Logic Circuits:
CAD Tools and VHDL
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 6-1
Introduction to CAD tools
A CAD system usually includes the following
tools
Design entry
Synthesis and optimization
Si
ECE380 Digital Logic
Introduction to Logic Circuits:
Design Examples
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 5-1
Design examples
Logic circuits provide a solution to a
problem
Some may be complex and difficult to
design
Regardless o
ECE380 Digital Logic
Optimized Implementation of
Logic Functions:
Karnaugh Maps and Minimum
Sum-of-Product Forms
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 7-1
Karnaugh map
The key to finding a minimum cost SOP or
POS form is applying th
ECE380 Digital Logic
Introduction to Logic Circuits:
Synthesis using AND, OR, and
NOT gates
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 4-1
Example logic circuit design
Assume we want to design a logic circuit with
three inputs x, y, and
ECE380 Digital Logic
Introduction to Logic Circuits:
Boolean algebra
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 3-1
Axioms of Boolean algebra
Boolean algebra: based
on a set of rules derived
from a small number of
basic assumptions
(axio
ECE380 Digital Logic
Number Representation and
Arithmetic Circuits:
Signed Numbers, Binary Adders
and Subtractors
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 17-1
Signed numbers
For signed numbers, in the binary system, the sign
of the nu
ECE380 Digital Logic
Introduction to Logic Circuits:
Variables, functions, truth tables,
gates and networks
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 2-1
Logic circuits
Logic circuits perform
operations on digital
signals
Implemented a
ECE380 Digital Logic
Combinatorial Circuit Building
Blocks:
Multiplexers
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 21-1
Multiplexers
A multiplexer (MUX) circuit has
A number of data inputs
One (or more) select inputs
One output
It p
ECE380 Digital Logic
Implementation Technology:
Standard Chips and
Programmable Logic Devices
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 10-1
Standard chips
A number of chips, each with a few logic
gates, are commonly used for small logi
ECE380 Digital Logic
Implementation Technology:
Look-up Tables, XOR and XNOR
gates
Electrical & Computer Engineering
Dr. D. J. Jackson Lecture 11-1
Look-up tables
A logic block commonly used in FPGA devices is the
look-up table (LUT)
An LUT contains sto