The document compares the topics of finite state machines covered in AS level to those in A2 level, noting that A2 level introduces new concepts like state transition diagrams, Mealy and Moore machines which output on state transitions, and deterministic and non-deterministic finite state automata. It also provides examples of finite state machines with outputs like a ballpoint pen and a vending machine, as well as machines without outputs like a basic combination lock.

1. Finite State Machines

2. AS and A2 compared
• AS Revision
– Finite state machines with output
• Mealy machines
– Finite state machines without outputs
– State Transition Tables
– Decision tables

3. A2 new topics
– State Transition Diagrams
– Finite state machines with output
• Mealy and Moore machines
– Finite State Automata
• Deterministic FSAs (DFAs)
• Non-Deterministic FSAs (NFAs)

4. Revision: Mealy Machines
Output on Transition
• Using Boole Deusto
• First task – ballpoint
pen.
• Two states, retracted
and extended. Input
is either a click (1) or
fumble (0). Output is Transition table for ballpoint
ready to write (1) or pen
not ready to write (0) Current R R E E
Input 1 0 1 0
Next E R R E
Output 1 0 0 0

5. Challenge
• Using Boole Deusto or JFLAP:
• Create a machine that outputs 0 unless
it sees the sequence 111, in which
case it outputs a single 1.
• Create a vending machine which takes
either 5p or 10p and gives 15p sweets
plus change.

6. Revision – FSMs without outputs
• Ultra-Basic combination
lock.
• Two digit code ‘20’
• Numbers 012
• Start State
• Accepting State Decision Table
First is 2 Y Y N N
• Use software VAS Second is 0 Y N Y N
Output Pass Y N N N

7. Revision – FSMs without outputs
• Ultra-Basic combination
lock.
• Two digit code ‘20’
• Numbers 012
• Start State
• Accepting State Decision Table
First is 2 Y Y N N
• Use software VAS Second is 0 Y N Y N
Output Pass Y N N N