dee2034 chapter 6 register

By:Siti Sabariah Hj. Salihin

Electrical Engineering Department

DEE2034 : DIGITAL ELECTRONICS1

CHAPTER 6 : REGISTER

Course Learning Outcomes, CLOUpon 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.


DEE2034 : DIGITAL ELECTRONICS

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



Introduction – Shift Register

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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

QDEE2034 : DIGITAL ELECTRONICS

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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


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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


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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


Parallel in / parallel out (PIPO)

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PIPO data movement.

Q3

Q2

CLK

Q1

Q0

1 0 1 1 1

000

0

1 0 10 0

0

0

1 1 1 1

0 0 1 0

D3

D2

D1

D0

1

0

1

0

0

1

1

0

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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


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

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


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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 1DEE2034 : DIGITAL ELECTRONICS

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Integrated circuits Shift Register

Chips for shift registers74164 is a 8-bit SIPO shift register

74164

CLK

CLR

AB

Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7


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Chips for shift registers

74165 is a 8-bit PISO register

74165

CLK

CLK INH

SH/LDSER

D0 D1 D2 D3 D4 D5 D6 D7

Q7

Q7



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Chips for shift registers74195 can be used as a 4-bit PIPO

register

74195

CLK

SH/LD

JK

Q0 Q1 Q2 Q3

CLR

D0 D1 D2 D3



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:


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:


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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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Ring Counter (continue)

Ring counters are used to construct “One-Hot” countersIt can be constructed for any desired MOD numberA 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

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Ring Counter

Q3 Q2 Q1 Q0


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22


0 0 0 1

1 0 0 0

0 1 0 0

0 0 1 0


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

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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


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Johnson Counter (Continue)


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Johnson Counter (Continue)

A

B

C

0 1 1 1

0 0 1 1

0 0 0 1

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.comDEE2034 : DIGITAL ELECTRONICS

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dee2034 chapter 6 register

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