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Finite State MachinesFinite State MachinesFinite State MachinesFinite State Machines

ASIC DESIGN USING FPGA

BEIT VII

KICSIT

Lecture 18-19

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Two Types of Logic CircuitsTwo Types of Logic Circuits

Lecture 18-19

Lecture 18-19 3

State MachineState Machine

• Any device that stores the status of something at a given time.

• Can operate on input to change the status and/or cause an action or output to take place for any given change.

Lecture 18-19 4

State MachineState Machine

• A Finite State Machine (FSM) is one that has a limited or finite number of possible states.

• There are a number of ways to show state machines, from simple tables through graphically animated illustrations.

Lecture 18-19 5

State MachineState Machine

• A computer is basically a state machine.

• Machine instruction is input that changes one or more states and may cause other actions to take place.

• The read-only memory from which a program is loaded stores a state.

• The boot program itself is an initial state.

• The application result is the output.

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States and State VariablesStates and State Variables

Lecture 18-19

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Basic Sequential ElementsBasic Sequential Elements

Lecture 18-19

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Simultaneous Input ChangesSimultaneous Input Changes

Lecture 18-19

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Setup and Hold TimeSetup and Hold Time

Lecture 18-19

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Mealy State MachineMealy State Machine

Lecture 18-19

• A Mealy state Machine’s output depends on both the state variables and the current input.

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Moore State MachineMoore State Machine

Lecture 18-19

• A Moore state Machine’s output depends only on the state variables.

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Mealy vs. MooreMealy vs. Moore

Lecture 18-19

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State Machine Design ProcessState Machine Design Process

Lecture 18-19

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Example of a State MachineExample of a State Machine

Lecture 18-19

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Machine States (Moore FSM)Machine States (Moore FSM)

Lecture 18-19

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States Diagram (Moore FSM)States Diagram (Moore FSM)

Lecture 18-19

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States Table (Moore FSM)States Table (Moore FSM)

Lecture 18-19

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Machine States (Mealy FSM)Machine States (Mealy FSM)

Lecture 18-19

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States Diagram (Mealy FSM)States Diagram (Mealy FSM)

Lecture 18-19

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States Table (Mealy FSM)States Table (Mealy FSM)

Lecture 18-19