1. By:
Siti Sabariah Hj. Salihin
Electrical Engineering Department
DEE2034 : DIGITAL ELECTRONICS
1
CHAPTER 6 : REGISTER
2. Course Learning Outcomes, CLO
Upon completion of the course, students should be able to:
CLO 3 : Draw logics diagrams, truth tables and timing diagrams for
all common flip flops and use these to implement sequential logic
circuits correctly.
CHAPTER 6 : REGISTER
DEE2034 : DIGITAL ELECTRONICS
3. Upon completion of this Chapter, students should be able to:
6.1 Understand the concepts and applications of registers and shift
Registers.
6.1.1 Classify the Shift Register according to the methods of data
input/output: SISO, PIPO, SIPO, PISO.
6.1.2 State the applications of Shift registers listed in 6.1.1
6.1.3 Interpret the Operation and circuit of Shift Register listed in
6.1.1
6.1.4 Interpret the Operation and application of an integrated
circuits
Shift Register listed in 6.1.1
6.1.5 Explain the application of Shift Register as arithmetic circuits:
6.1.6 Explain the operations and application of Ring Counters and
Johnson Counter
CHAPTER 6 : REGISTER
DEE2034 : DIGITAL ELECTRONICS
4. Introduction – Shift Register
4
Shift registers are constructed using several flip-
flop, connected in such a way to STORE and
TRANSFER/ Shift digital data.
Basically, D flip-flop is used. The input data
(either ‘0’ or ‘1’) is applied to the D terminal and
the data will be stored at Q during
positive/negative-edge transition of the clock
pulse. D Q
Q
DEE2034 : DIGITAL ELECTRONICS
5. 5
One D FF is used to store 1-bit of data. Thus, the
number of flip-flops used is the same with the
number of bit stored.
Shift register mean that the data in each FF can be
transferred/move to other FF upon edge triggering
of the clock signal.
Four types of data movement in shift register are:-
Parallel in / parallel out (PIPO)
Serial in / serial out (SISO)
Parallel in / serial out (PISO)
Serial in / parallel out (SIPO)
Shift Register
DEE2034 : DIGITAL ELECTRONICS
6. 6
Serial Parallel
•Movement of N-bit data
require N number of CLK
pulses. Thus, the operation is
slow.
•Only one FF is required to be
connected at the output
terminal, thus only one wire is
required.
•Require only one CLK pulse
to transfer all N-bit of data.
Thus, operation is faster than
serial.
•Required N number of
connection to the output
terminal, which is proportional
to the number of bit. Thus, too
many connection is required.
Serial Data VS Parallel Data movement
DEE2034 : DIGITAL ELECTRONICS
7. 7
D Q2
CP
D Q1
CP
D Q3
CP
D Q0
CP
D3 D2 D1 D0
Q3 Q2 Q1 Q0
Flip-flop configuration for PIPO register.
CLK
DEE2034 : DIGITAL ELECTRONICS
9. 9
Flip-flop connection for SISO.
D Q1
FF1
CP
D Q2
FF2
CP
D Q0
FF0
CP
D Q3
FF3
CPCLK
DIN
1st CLK 2nd CLK 3rd CLK 4th CLK
DEE2034 : DIGITAL ELECTRONICS
10. Serial in / serial out (SISO)
10
SISO data movement. Binary data 10111 is transferred!
DATA-IN
Q3
Q0
Q1
1st
CLK
2nd 3rd 4th 5th
Q2
1 0 1 1 1
11. 11
Flip-flop connection for PISO
D Q1
FF1
CP
D Q2
FF2
CP
D Q0
FF0
CP
D Q3
FF3
CPCLK
D0 D1 D2 D3SHIFT/LOAD
Serial
data
out
DEE2034 : DIGITAL ELECTRONICS
12. 12
Parallel in / serial out (PISO)
PISO data movement.
SHIFT/
LOAD
CLK
Q3
0
0 1 1 1
1 0 1
0
0
0
1
1 1 1 1
0 0 1 1
D0
D1
D2
D3
1 00 1 0 1
DEE2034 : DIGITAL ELECTRONICS
13. 13
Integrated circuits Shift Register
Chips for shift registers
74164 is a 8-bit SIPO shift register
74164
CLK
CLR
A
B
Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7
DEE2034 : DIGITAL ELECTRONICS
14. 14
Chips for shift registers
74165 is a 8-bit PISO register
74165
CLK
CLK INH
SH/LD
SER
D0 D1 D2 D3 D4 D5 D6 D7
Q7
Q7
Integrated circuits Shift Register
DEE2034 : DIGITAL ELECTRONICS
15. 15
Chips for shift registers
74195 can be used as a 4-bit PIPO
register
74195
CLK
SH/LD
J
K
Q0 Q1 Q2 Q3
CLR
D0 D1 D2 D3
Integrated circuits Shift Register
DEE2034 : DIGITAL ELECTRONICS
16. Shift Register as Divider 2 circuits
Example :
14 = 1 1 1 0
7 = 0 1 1 1
3.5= 3 = 00 1 1
1.5 = 1 = 0 0 0 1
Notes : Shift to RIGHT as divider 2.
Shift Register as arithmetic circuits:
DEE2034 : DIGITAL ELECTRONICS
17. Shift Register as Multiplier 2 circuits
Example :
8 = 1000
16 = 10000
32 = 100000
64 = 1000000
Notes : Shift to LEFT as Multiplier 2.
Shift Register as arithmetic circuits:
DEE2034 : DIGITAL ELECTRONICS
18. 18
A shift register counter is a shift register whose
output being fed back (connected back) to the
serial input. This shift register would count the
state in a unique sequence!
Two types of shift register counter:-
The ring counter
The Johnson counter
Shift Register Counters
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19. 19
Ring Counter (continue)
Ring counters are used to
construct “One-Hot”
counters
It can be constructed for any
desired MOD number
A MOD-N ring counter uses
N flip-flops connected in the
arrangement as shown in fig.
a)
In general ring-counter will
require more flip-flops than a
binary counter for the same
MOD number DEE2034 : DIGITAL ELECTRONICS
23. Exercise: Draw a 3 Bit Ring Counter
Circuit with initial input 010 . show a True
Table until 8 clock pulse/number sequence and draw the
output waveform.
Answer:
Discuss with Your lecturer
23
Ring Counter (continue)
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24. 24
Johnson Counter
Or Twisted-ring counter
Johnson counter constructed exactly like a normal ring counter
except that the inverted output of the last flip-flop is fed back to
first flip-flop
DEE2034 : DIGITAL ELECTRONICS
27. 1. "Digital Systems Principles And Application"
Sixth Editon, Ronald J. Tocci.
2. "Digital Systems Fundamentals"
P.W Chandana Prasad, Lau Siong Hoe,
Dr. Ashutosh Kumar Singh, Muhammad Suryanata.
REFERENCES:
Download Tutorials Chapter 5: Register
http://www.portal.cidos.edu.my
http://www.baiasalihin.wordpress.com
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28. 28EE 202 : DIGITAL ELECTRONICS
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