Mealy and Moore machines - Micro-controllers - FSM

Mealy and Moore machines(Micro-controllers -FSM)

A.Moore machine
–Associates its outputs with states
–The outputs are represented either within the vertex corresponding to a state or adjacent to the vertex

B.Mealy machine:
–Associates its outputs with the transitions
–In addition to the input values, each arc also shows the output values generated during the transition; the format of the label of each arc is Inputs/Outputs.

More Links:

Finite State Machine-Tutorials and Examples-1
Finite State Machine-Tutorials and Examples-2
FSM - Finite State Machine-Digital Electronics
Embedded programming-Micro controller based Systems

Both can be used to represent any sequential system and each has its advantages.

Mealy FSM

1. Output is dependent on the inputs and the current state
2. Delayed output FSM implies the fact that the calculated output for an input applied at time t is assigned at time t+1. This is correct at an Mealy FSM

Mealy machine diagram

1. Self arcs must be shown (because the output values are shown on the arcs) 
2. Can be more compact than Moore machine, especially when two or more arcs with different output values go into the same state

Moore FSM

1. Output is dependent only on the current state 
2. Immediate Moore FSM: the output is obtained with a clock period delay, since the then the next state becomes present state 
3. Delayed Moore FSM: the output is actually obtained with two clock period delay, because of the Registers Bank 2 

Moore machine diagram

1. Self arcs can be missing (since it outputs are associated with the states and not with the arcs) 
2. Offers a simpler implementation when the output values depend only on the state and not on the transitions 
3. It requires less hardware to produce the output values than does a Mealy machine, since its outputs depend only on its state and its input values 
4. It is well suited for representing the control units of microprocessors