Govt. Engineering College- Gandhinagar

It is all about……  STATE MACHINE

What is a state machine?  A state machine is a different way of thinking about computation  A state machine has some number of states, and transitions between those states  Transitions occur because of inputs  A “pure” state machine only knows which state it is in—it has no other memory or knowledge

 A State Machine or a sequential machine is a system that can be described in terms of a set of states that the system may enter into.  Once the system is in particular state, it may remain there for some finite time duration. This decides the memory capability of state machine.  The next state of FSM depends on the present states and output. The output also depends on present states and inputs.

State machine I/O  State machines are designed to respond to a sequence of inputs, such as The individual characters in a string A series of external events  State machines may produce output (often as a result of transitions)  Alternatively, the “result” of a state machine may be the state it ends up in

 This shows that the sequential machine consists of combinational circuits alongwith memory elements.  The memory element will always appear in the feedback path.  Present state is stored in memory elements. They are applied to combinational circuit alongwith external inputs.

A Finite State Machine  A sequential logic unit which Takes an input and a current state Produces an output and a new state  It is called a Finite State Machine because it can have, at most, a finite number of states.  It is composed of a combinational logic unit and flip-flops placed in such a way as to maintain state information.

Representing a Finite State Machine  It can also be represented using a state diagram which has the same information as the state transition diagram. State 0 State 1

Block Diagram:-

Classification of State Machine:  State Machine are classified on the following two basis:-  On the basis of clock  On the basis of model used

On the basis of Clock:-  Synchronous State Machine:  If the state machine changes its state in response to the clock and if all the inputs are synchronous then its called synchronous state machine  Asynchronous State Machine:  If the changes in the state are based on only input and output and not on the clock then its Asynchronous State Machine

On the basis of Model:- Mealy Machine: Output as a function of both inputs and current states

Moore Machine:-Output as a function of current state only

Presented By:-  Khatwani Falguni( )