ECE 375: Digital Design II
Class 4Moore Machine
To detect the sequence: 101
State Diagram:
Alphanumeric FSM
A sequential circuit with many inputs. It's not effective to label state with 1s and 0s
2 inputs: F (forward) and R (reverse) Outputs: Z1, Z2, Z3....Zn
Alphanumeric Diagram:
Diagram with values:
How to fix deadlocks?
For every state:
- P1: For any combination of inputs, at least one transition state is enabled. (Deadlocks)
- P2: For any combination of inputs, no more than one transition is enabled. (Deterministic)
Fixed Diagram:
T1 = F'R'
T2 = F
T3 = F'R
You can prove it follows the rules using boolean algebra:
P1 => T1 + T2 + T3 = 1 => F'R' + F'R + F = 1 => F'(R' + R) + F = 1 => F' + F = 1 => 1 = 1 It satisfies the requirements of P1
P2 => T1 T2 = 0 => F'R' F => (F' F)R' = 0 P2 => T1 T3 = 0 => F'R' F'R = 0 => F'(*R' R) = 0 P2 => T2 T3 = 0 => F F'R = 0 => (F' * F***)R = 0 It satisfies the requirements of P2