CS 140L Lecture 7 Transformation between Mealy and Moore Machines

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CS 140L Lecture 7Transformation between Mealy
and Moore Machines

• Professor CK Cheng
• CSE Dept.
• UC San Diego

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Outlines

• Framework
• Procedure
• Example Transform
• Example State Diagram
• Example Output Sequence

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Transform from Mealy to Moore Machine
Mealy Machine y(t) f(x(t), s(t)) Moore
Machine y(t) f(s(t)) s(t1) g(x(t), s(t))
x(t)
x(t)
C1
C2
y(t)
C1
C2
y(t)
CLK
CLK
s(t)
s(t)
Moore Machine
Mealy Machine
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Transform from Mealy to Moore Machine
Algorithm Input State Table of Mealy machine
1) For each NS, z Si,yj create a state Si(j) 2)
For each new state Si(j), repeat the row PS
Si 3) Replace NS, z Si,yj with state Si(j).
Set output z yj for row PS Si(j)
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Example
Mealy Machine
PS A B
00 A,0 A,1
01 A,1 B,0
10 B,0 B,0
(x,y) (NS, z)
Moore Machine
PS A0 A1 B
(x,y)
00 A0 A0 A1
01 A1 A1 B
10 B B B
z 0 1 0
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Mealy Machine
State Diagram
Moore Machine
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Timing Diagrams
Time step x y S
z S z
0 0 0 A 0 A0 0
1 0 1 A 1 A0 0
2 1 0 A 0 A1 1
3 0 0 B 1 B 0
4 0 1 A 1 A1 1
5 0 1 A 1 A1 1
A
Mealy
A1 1
Moore
The output shifts by one clock from Mealy to
Moore machine