04/12/2023Algorithmic State Machine

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RAVITESH MISHRA

A SS I STA N T P R O F E SSO R

B C E , M A N D I D E E P

ALGORITHMIC STATE MACHINE

04/12/2023Algorithmic State Machine

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Algorithmic State Machine (ASM)

It is a sequential network which controls a

digital system that carries out a step-by-step

procedure or algorithm.

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04/12/2023Algorithmic State Machine

Principal components of a SM chart

1.State Box : Contains output list.

2. Decision Box : Condition is placed.

3. Conditional Output Box : Contains conditional output list.

4. ASM Block : contains one or more exit paths. Describes machine operation

04/12/2023Algorithmic State Machine

4Contains only one state box For Z=A+BC Put (A+BC) in one decision box & Z in one Conditional output box

Put each term in condition boxIf A=1,Z=1If A=0 (B=0,Z=0 or B=1,C=0/1,z=0/1)

ASM chart for combinational circuits

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04/12/2023Algorithmic State Machine

ASM chart in equivalent form

The other equivalent charts for Z=A+BC are

Algorithmic State Machine 04/12/2023

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There are two types o f machines 1 . M E A LY M A C H I N E 2 . M O O R E M A C H I N E

1. M A E LY M A C H I N E : O u t p u t i s f u n c t i o n o f b o t h i n p u t & p r e s e n t s t a t e

Steps f o r mak ing ASM char ti ) Represen t s ta te by s ta te boxes .i i ) A f t e r each box pu t i npu t i n each box .i i i ) Depend ing on va lues o f ou tpu t the ou tpu t i n cond i t i ona l

box i n pa ths where i t w i l l be “1” .i v ) Depand ing on va lues o f i npu t connec t the pa th to nex t

s ta te box .

Development of ASM chart from state graph

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Example of development of ASM chart from Mealy Machine Consider the Mealy state graph of 111 detector.

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04/12/2023Algorithmic State Machine

2. MOORE MACHINE

:Output depends on present state

Steps

1. For each state draw stae box ,put output in state box if it is ‘1’.

2. Put input in decision box after each state box.

3. Connect next state link by inspecting state graph.

Example: Consider 111 sequence detector.

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Advantages of ASM chart

Easy to understand.May have one or more equivalent forms.Can describe both combinational &

sequential circuits.Have structured approach to visualise a

sequential problem.