ECE 375: Digital Design II

Class 4

Moore 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:

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