1

CHAPTER 9

REGISTERS

2

REGISTER WITH PARALLEL LOAD

Load Clock Clear Function

0

1

x

x

↓

x

1

1

0

No change

Load

clear

3

SHIFT REGISTER BASICS

4

SERIAL IN/SERIAL OUT SHIFT REGISTERS

CP

5

Operation Of Shift Registers

Clock

pulse

Serial I/P

Bit

State of register

( parallel outputs )

Serial

0/P bit

Initial 1 0 1 1 1 1

1 1 1 0 1 1 1

2 0 1 1 0 1 1

3 1 0 1 1 0 0

4 x 1 0 1 1 1

6

PARALLEL IN/SERIAL OUT SHIFT REGISTERS

7

4-bit parallel in/serial out shift register

8

BIDIRECTIONAL SHIFT REGISTER

No change

Shift right

Shift left

Parallel load

9

The function table of the register

S1 S0 Operation

0

0

1

1

0

1

0

1

No change.

Shift right.

Shift left.

Parallel load.

10

Ring Shift Counter

11

Ring Shift Counter Operation

Q3 Q2 Q1 Q0 0 0 0 1 0 0 1 0 0 1 0 0 1 0 0 0

12

Johnson Shift Counter

13

Johnson Shift Counter Operation

14

Q3 Q2 Q1 Q0 T0 0 0 0 0 T1 0 0 0 1 T2 0 0 1 1 T3 0 1 1 1 T4 1 1 1 1 T5 1 1 1 0 T6 1 1 0 0 T7 1 0 0 0 T0 0 0 0 0