1. Elements of Sequential Design
What one thing do these items have in common, lacking in combinational circuits?
calculators
cell phones
people
computers
tennis racquets (w/chips)
alarm systems
etc.

2. Elements of Sequential Design
SR Latch
circuit symbol
equations truth table
Q+ ≡ (R + QN)' S R Q QN
last 1
QN+ ≡ (S + Q)'

3. Elements of Sequential Design
SR Latch (timing diagram)
Note: Ignores ramp time

4. Elements of Sequential Design
D latch
circuit symbol
equations truth table
Q+ ≡ CD + QN' C D Q QN 1 x
last
QN+ ≡ CD' + Q'

5. Elements of Sequential Design
D latch (timing diagram)
Note: D latch also known as a transparent latch

6. Elements of Sequential Design
Edge-triggered D flip-flop
circuit symbol
truth table

7. Elements of Sequential Design
D flip-flop (timing diagram)

8. Elements of Sequential Design
Edge-triggered JK flip-flop
circuit symbol
truth table
equations (last 4 rows)
Q+ ≡ QN J + QK'
QN+ ≡ Q'

9. Elements of Sequential Design
JK flip-flop (timing diagram)

10. Elements of Sequential Design
Registers
fast and relatively simple way to store data
integral part of CPU
Parallel load register

11. Elements of Sequential Design
Registers
Serial load register

12. Elements of Sequential Design
Registers
Serial-in or parallel-in register

13. Elements of Sequential Design
Summary of Topics
SR latch
D latch
D flip-flop
JK flip-flop
Registers
serial load
parallel load
serial or parallel load