Sequential systems

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Lecture VIII

• Sequential systems
• Introduction

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AND , Or , NOT gates
Truth tables
Sequential systems? State tables or state diagrams
Flip-Flops
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Latches and Flip-Flops
NOR gate latch
store
reset
set
Not be allowed
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Chatterless switch
NAND gate latch
5
gate
Store --disable
A normal latch--enable
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Flip-Flops-----clocked binary storage device
clock
Slave
Master
clock
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S-R Flip-Flop
clock
clock
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J-K Flip-Flop
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D type T type Flip-Flops
Delay
Toggle
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State table and state diagram (E.F. Moore)
The output depends only on the state of the
system.
Control input x
Moore state diagram
input
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State table and state diagram (G.B. Mealy)
The output depends on the present input, as well
as the state.
Mealy state diagram
A
state
D
B
C
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0
1
clock
0
1
13
Preset and clear