Chapter 8. Sequential machine

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Chapter 8. Sequential machine
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Example)
Compatible pairs of states (1,2) (1,3) (1,4)
(1,5) (1,6) (2,3) (2,4) (2,5)
(2,6) (3,4) (3,5) (3,6) (4,5)
(4,6) (5,6)
Maximal Compatible Set (1,2,6) (1,4) (2,3,6)
(2,5,6) (3,4) (4,5)
Set of maximal compatible set of compatible
states (i.e., a compatibility class) which
cannot be contained in any larger
compatibility class.
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Synthesis of synchronous sequential circuits 1.
From the specification of problem, from a state
table (or a state diagram)
2. Minimize the machine

3.
Select a state assignment and determine the type
of memory elements
4. Drive output transition and output
tables
5. Draw a
circuit diagram
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Maximal compatible class

(ABCI), (ABDFI), (CHJ),
(DGI), (EG), (EH), (F,J)
Best closed cover (ABCI), (DFI),
(EG), (DHJ)
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• Homing sequence to identify the final state.
• The input sequence which, when applied starting
  in any initial state, allows the final state to
  be uniquely determined by observing the output
  sequence produced.

Input seq 00 Output seq 01 ?A Output seq 10 ?C
All machine has homing sequence

• Synchronizing sequence the input sequence which
  drives a machine to a known
  state, independent of the
  output sequence produced.

111 synchronizing sequence
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