Mealy state machine

1. Mealy state machine
•In the theory of computation, a Mealy machineis a finite state transducerthat
generates an output based on its current state andinput. This means that the state
diagramwill include both an input and output signal for each transition edge.
•In contrast, the output of a Moore finite state machinedepends only on the machine's
current state; transitions are not directly dependent upon input.
•The use of a Mealy FSM leads often to a reduction of the number of states.
•However, for each Mealy machine there is an equivalent Moore machine.

2. Mealy state machine

3. Moore state machine
•In the theory of computation, a Moore machineis a finite state transducer
where the outputs are determined by the current statealone (and do not
depend directly on the input). The state diagramfor a Moore machine will
include an output signal for each state. Compare with a Mealy machine,
which maps transitionsin the machine to outputs.
•The advantage of the Moore model is a simplification of the behavior.

4. Moore state machine

5. Example
•Q3.Derive a minimal state table for a single-input and
single-output Moore-type FSM that produces an output
of 1 if in the input sequence it detects either 110 or 101
patterns. Overlapping sequences should be detected.
(Show the detailed steps of your solution.)

7. State Diagram
A/z=0
w=1
Reset
w=0
B/z=0 F/z=1
C/z=0
D/z=1
E/z=0
w=0
w=1
w=1
w=1
w=1
w=0
w=0
w=0
w=1
StateDiagram

8. Sate Table (Moore FSM)
Present
state
Next State Output
Z
w=0 w=1
A A B 0
B E C 0
C D C 0
D A F 1
E A F 0
F E C 1
6 states need 3 flip-flops

9. State Assignment (Mealy FSM):
state A: Got no 1
state B: Got”1”
state C: Got”11”
state D: Got”10”
A
1/0
Reset
0/0
B
D
C
1/0
0/1
1/1
1/0
0/0
StateDiagram
0/0

10. Sate Table (Mealy FSM)
Present
state
Next State Output Z
w=0 w=1 w=0 w=1
A A B 0 0
B D C 0 0
C D C 1 0
D A B 0 1
4 states need 2 flip-flops