Mealy Finite State Machine

Description:

• Output is shown on the Transition Function alongside input

As a Circuit:

• As output does depend on input with the state the input arrive, output combinational logic need to include input and the state

As a Table:

	Next -	- state/out
Current state (S)	In = 0	In = 1
Init	Init / 0	Got1 / 0
Got1	Init / 0	Got11 / 0
Got11	Init / 0	Got11 / 1

Binary State Coding:

• Convert the state names from table above into binary
• Where Q1 and Q0 are binary for the states
• Let D1 and D0 be the Flip-flop for the state
  • So Q0=D0, Q1=D1
• State encoding:

	Q1Q0	Q1Q0
Q1Q0	In = 0	In = 1
00	$00$/0	$01$/0
01	$00$/0	$10$/0
10	$00$/0	$10$/1

• We can use the the state bits to encode state, let left bit of each state be D0 and the next left be D1
• Then we have the truth table for each state bit
  • ex: for D0, we take the red bits of Q0
    • D0=In.Q1’.Q0’ using Karnaughmap

In \ Q1Q0	00	01	11	10
0	0	0	x	0
1	1	0	x	0

• For D1, we take the green bits
  • D1=In.Q1 + In.Q0

In\Q1Q0	00	01	11	10
0	0	0	x	0
1	0	1	x	1

• Out = In.Q1 + In.Q0 as output only depends on state???
• Output is from state and input, Out = In.Q1

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