Digital ElectronicsDigital Electronics

Electronics TechnologyElectronics Technology

Landon Johnson

Shift Registers

DIGITAL INTEGRATED CIRCUITS

SMALL SCALE INTEGRATIONLESS THAN 12 GATES

MEDIUM SCALE INTEGRATION12 TO 99 GATES

LARGE SCALE INTEGRATION100 TO 9999 GATES

GATES FLIP FLOPSENCODERSDECODERS

SHIFTREGISTERS

MULTIPLEXERSDEMULTIPLEXERS

ADDERS MEMORYSMALL

MICROPROCESSORS

Shift Register Competencies39. Without references, the student will define the 39. Without references, the student will define the term “Serial Data Transmission” with 100% accuracy.term “Serial Data Transmission” with 100% accuracy.

40. Without references, the student will define the 40. Without references, the student will define the term “Parallel Data Transmission” with 100% term “Parallel Data Transmission” with 100% accuracy.accuracy.

41. Without references, the student will define the 41. Without references, the student will define the acronym “SISO” with 100% accuracy.acronym “SISO” with 100% accuracy.

42. Without references, the student will define the 42. Without references, the student will define the acronym “SIPO” with 100% accuracy.acronym “SIPO” with 100% accuracy.

Shift Register Competencies43. Without references, the student will define the 43. Without references, the student will define the acronym “PISO” with 100% accuracy.acronym “PISO” with 100% accuracy.

45. Given a specified register, the student will 45. Given a specified register, the student will draw the register with 100% accuracydraw the register with 100% accuracy

44. Without references, the student will define the 44. Without references, the student will define the acronym “PIPO” with 100% accuracy.acronym “PIPO” with 100% accuracy.

46. Given a specified SISO or SIPO register, the student 46. Given a specified SISO or SIPO register, the student will state the number of pulses to completely load the will state the number of pulses to completely load the register with 100% accuracy.register with 100% accuracy.

PARALLEL SHIFT REGISTERPARALLEL SHIFT REGISTERLab 18.Lab 18.

SD

CPRQN

QS

D

CPRQN

QS

D

CPRQN

Q

SJCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

Q

SD

CPRQN

QS

D

CPRQN

QS

D

CPRQN

Q

SJCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

Q

SERIAL SHIFT REGISTERSERIAL SHIFT REGISTERLab 18.Lab 18.

data in

clearclk

SJCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

QS

JCPK

RQN

Q

SHIFT REGISTER VOCABULARYSHIFT REGISTER VOCABULARYREGISTER- group of flip flops capable of storing data.SERIAL DATA TRANSMISSION- transfer of data from one place to another one bit at a time.

PARALLEL DATA TRANSMISSION- simultaneous transfer of all bits of a data word from one place to another.

SISO- SERIAL IN/SERIAL OUT- type of register that can be loaded with data serially and has only one serial output.

SIPO- SERIAL IN/PARALLEL OUT- type of register that can be loaded with data serially and has parallel outputs available.PISO- PARALLEL IN/SERIAL OUT- type of register that can be loaded with parallel data and has only one serial output.PIPO- PARALLEL IN/PARALLEL OUT- type of register that can be loaded with parallel data and has parallel outputs available.

INTEGRATED CIRCUIT REGISTERSINTEGRATED CIRCUIT REGISTERS

Lab 27.Lab 27.

•74194A BIDIRECTIONAL UNIVERSAL SHIFT REGISTER

LAB 27 b.SERIAL OPERATION

DCBA

74LS194CP

S1S0

DSRDSL

MR

D3D2D1D0

Q3Q2Q1Q0

74LS194CP

S1S0

DSRDSL

MR

D3D2D1D0

Q3Q2Q1Q0

OVERVIEW OFSHIFT REGISTERS

• Common tasks of shift registers:– Serial/parallel data conversion– UART (an example)– Time delay– Ring counter– Twisted-ring counter or Johnson counter– Memory device

• A shift register is a sequential logic device made up of flip-flops that allows parallel or serial loading and serial or parallel outputs as well as shifting bit by bit.

CHARACTERISTICS OF SHIFT REGISTERS

•Number of bits (4-bit, 8-bit, etc.)

•Loading– Serial– Parallel (asynchronous or synchronous)

•Common modes of operation.– Parallel load– Shift right-serial load– Shift left-serial load– Hold– Clear

•Recirculating or non-recirculating

SERIAL/PARALLEL DATA CONVERSION

1 0 1 0 1 1 1 1Serial in Serial out

Shift registers can be used to convert from serial-to-parallel or the reverse from parallel-to-serial.

1 0 1 0 1 1 1 1Serial in

Parallel out

1 0 1 0 1 1 1 1 Serial out

Parallel in

1 0 1 0 1 1 1 1

Parallel in

Parallel out

SERIAL LOAD SHIFT REGISTER

Note the use of D FFs.Clock (CLK) inputs wired in parallel.

Clear (CLR) inputs can be activated with LOWor disabled with HIGH.

Preset (PS) inputs deactivated.

Parallel outputs here.Order= A B C D

Inputs here:(1) Data(2) Clock(3) Clear

Clear input:Active = 0

Deactivated = 1

Clock input:Positive-edge

triggeringClock Pulse 1

Clear = 0

Data = 1

0 0 0 01 0 0 0

Clock Pulse 2

Clear = 1

Data = 1

1 1 0 00 1 1 0

Clock Pulse 3

Clear = 1

Data = 1

Clock Pulse 4

Clear = 1

Data = 0

0 0 1 1

Clock Pulse 5

Clear = 1

Data = 0

0 0 0 1

Clock Pulse 6

Clear = 1

Data = 0

Clock Pulse 7

Clear = 1

Data = 1

1 0 0 00 1 0 0

Clock Pulse 8

Clear = 1

Data = 04-bit

serial-inparallel outshift right

shift register

Clock Pulse 1

Clear = 0

Data = 1

Clock Pulse 2

Clear = 1

Data = 1

Clock Pulse 3

Clear = 1

Data = 0

Clock Pulse 4

Clear = 1

Data = 0

Clock Pulse 5

Clear = 1

Data = 1

QUESTION #1This is a ___ type shift register.

A. Serial-in, parallel outB. Parallel-in, serial-out

A: Serial-in, parallel-out

QUESTION #2What is the 4-bit output (bit A on left, D on right) after pulse 1?

A: 0000

QUESTION #3What is the 4-bit output (bit A on left, D on right) after pulse 2?

A: 1000

QUESTION #4What is the 4-bit output (bit A on left, D on right) after pulse 3?

A: 0100

QUESTION #5What is the 4-bit output (bit A on left, D on right) after pulse 4?

A: 0010

QUESTION #6What is the 4-bit output (bit A on left, D on right) after pulse 5?

A: 1001

QUESTION #7What is the 4-bit output (bit A on left, D on right) after pulse 6?

A: 1100

Clock Pulse 6

Clear = 1

Data = 1

TEST

PARALLEL LOAD SHIFT REGISTER

Note the use of J-K FFs.Clock (CLK) inputs wired in parallel.

Clear (CLR) input activated with LOW.Parallel load inputs (A,B,C,D) are active LOW.

Note therecirculating

lines.

Outputs here.Order= A B C D

Parallel datainputs

(Active LOW)

Clock input- H-to-L

Clear input- Active LOW

Recirculatinglines:

Pass data fromFFD to FFA

on eachclock pulse.

RECIRCULATING SHIFT REGISTER

0 0 0 0

Clock pulse 1

Clear input= 0

Parallel data inputs=only D activated

0 0 1 1

Clock pulse 2

Clear input= 1

Parallel data inputs=C & D activated

Clock pulse 3

Clear input= 1

Parallel data inputs=all inactive

1 0 0 1

Clock pulse 4

Clear input= 1

Parallel data inputs=all inactive

1 1 0 0

Clock pulse 5

Clear input= 1

Parallel data inputs=all inactive

0 1 1 0

Clock pulse 6

Clear input= 1

Parallel data inputs=all inactive

0 0 1 1

Clock pulse 7

Clear input= 0

Parallel data inputs=all inactive

0 0 0 0

Clock pulse 8

Clear input= 1

Parallel data inputs=only B active

0 1 0 0

UNIVERSAL SHIFT REGISTER IC

74194 Universal 4-bit Shift Register IC.Modes of operation: Hold, Parallel load, Shift right & Shift left.

An active LOW Clear (CLR) input overrides all others.

Outputs here

Mode Controls:

HoldParallel loadShift rightShift left

Clock inputL-to-H triggering

Parallel data inputs

Order: A, B, C, Dduring Parallel loading

Clear inputactive LOWSerial data Right input

used during Serial Load Right

mode of operation

Serial data Left inputused during

Serial Load Leftmode of operation

USING THE 74194 SHIFT REGISTER IC

CLR = 1

Serial R = X

Parallel Load= 0 1 1 0

Serial L = X

Clock pulse 1 (L-to-H)

S0= 1

S1= 1

0 1 1 0

X = Irrelevant

CLR = 1

Serial R = 0

Parallel Load= 0 1 1 0

Serial L = X

Clock pulse 2 (L-to-H)

S0= 1

S1= 0

0 0 1 1CLR = 1

Serial R = 0

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 3 (L-to-H)

S0= 1

S1= 0

0 0 0 1CLR = 1

Serial R = 0

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 4 (L-to-H)

S0= 0

S1= 0

0 0 0 1CLR = 0

Serial R = 0

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 5 (L-to-H)

S0= 1

S1= 1

0 0 0 0CLR = 1

Serial R = X

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 6 (L-to-H)

S0= 1

S1= 1

0 1 0 0CLR = 1

Serial R = X

Parallel Load= 0 1 0 0

Serial L = 1

Clock pulse 7 (L-to-H)

S0= 0

S1= 1

1 0 0 1CLR = 1

Serial R = X

Parallel Load= 0 1 0 0

Serial L = 0

Clock pulse 8 (L-to-H)

S0= 0

S1= 1

0 0 1 0

CLR = 0

Serial R = X

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 1 (L-to-H)

S0= 1

S1= 1

? ? ? ?

CLR = 1

Serial R = 0

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 2 (L-to-H)

S0= 1

S1= 1

CLR = 1

Serial R = 0

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 3 (L-to-H)

S0= 1

S1= 0

CLR = 1

Serial R = 0

Parallel Load= 0 1 0 0

Serial L = X

Clock pulse 4 (L-to-H)

S0= 0

S1= 0

CLR = 1

Serial R = X

Parallel Load= 0 1 0 0

Serial L = 1

Clock pulse 5 (L-to-H)

S0= 0

S1= 1

QUESTION #1The 74194 IC could be described as a 4-bit (shift right, universal)shift register.

A: Universal

QUESTION #2What is the mode of operation during and the output of the shift register after pulse 1?

A: Clear, 0 0 0 0

QUESTION #3What is the mode of operation during and the output of the shift register after pulse 2?

A: Parallel load, 0 1 0 0

QUESTION #4- What is the mode of operation during and the output of the shift register after pulse 3?

A: Shift right, 0 0 1 0

QUESTION #5What is the mode of operation during and the output of the shift register after pulse 4?

A: Hold, 0 0 1 0

QUESTION #6What is the mode of operation during and the output of the shift register after pulse 5?

A: Shift left, 0 1 0 1

CLR = 1

Serial R = X

Parallel Load= 0 1 0 0

Serial L = 1

Clock pulse 6 (L-to-H)

S0= 0

S1= 1

QUESTION #7What is the mode of operation during and the output of the shift register after pulse 6?

A: Shift left, 1 0 1 1

TEST

SIMPLE TROUBLESHOOTING HINTS

• Feel top of IC to determine if it is hot

• Look for broken connections, signs of

excessive heat

• Smell for overheating

• Check power source

• Trace path of logic through circuit

• Know the normal operation of the circuit