1. EE 1001 Digital Topics Introduction to Electrical Engineering
Dr. Chris Carroll
MWAH 252
ccarroll

2. Digital Logic Foundation for digital computer design
Basics are easy. . .
Discrete, two-valued variables
Finite number of possible functions
Complex operations built from easy basics
Combinational circuits (no memory)
Sequential circuits (memory)

3. Combinational Circuits
AND gate
OR gate
NOT gate
Inputs X Y Z
Combinational
Circuit
Output
(function of what X, Y, and Z are right now)

4. Sequential Circuits Flip-flops capture “state” of the circuit D Q
clock
Inputs X Y Z
Sequential
Circuit
Output
(function of what X, Y, and Z are right now and the recent history of their values.

5. Switch Networks
You are supplied with an unlimited number of two different kinds of switches Ends connected Ends connected if X = 1 if X = 0 X X

6. Example Switch Networks
Source of 1’s Source of 1’s Source of 0’s Source of 0’s A
Network of
Switches
Function
Not A A

7. AND/OR Switch Networks
Source of 1’s Source of 1’s Source of 0’s Source of 0’s
Network of
Switches
Network of
Switches
A AND B
=1 if A=B=1
else =0
A OR B
=0 if A=B=0
else =1

8. AND/OR Switch Networks
Source of 1’s Source of 1’s Source of 0’s Source of 0’s A A B B
A AND B
A OR B A A B B

9. Complex Switch Network
Source of 1’s Source of 0’s
Network of
Switches
1 if A=0 or if A=B=C=1, else 0

10. Surprising Switch Network
Source of 1’s Source of 0’s B A C
1 if A=0 or if A=B=C=1, else 0 A B C

11. Computer Architecture
How to build a computer
Many philosophies
Complex Instruction Set Computer (CISC)
Reduced Instruction Set Computer (RISC)
Always three parts of any computer
Central Processing Unit (CPU)
Memory (for both program and data)
Input/Output (I/O)

12. Summary Digital is everywhere! Even analog things can be digitized
Complexity is manageable
High performance, low cost