ECE 287 – Lecture 14

Finite State Machines - I

Announcements

• Next Quiz on Wednesday after Exam• Exam II – Nov 15th

• Last Day to Demo Labs – Nov 14th

• Project Oral Proposal - Nov 1st

Robot control START

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1) System of inputs, outputs and states• Peter: Assume input for question and input

for if action complete

2) State Diagram

3) Encode States

4) State table

5) Build Circuit

State Machine Generalization

State

Combinational circuit

Inputs outputs

Current State

Next State

Example 2

Turn a light on every 4 cycles of a clock using a state machine

Problem Set

1. Build a finite state machine for the following state diagram:

A

B

G

In = 0

In = 0

In = 0

In = 1

In = 1

In = 1

Out = 1

Out = 1

Out = 0

Problem Set

1. Build a finite state machine for:• Design a state machine controller for an elevator. The elevator can be at one of two

floors: Ground or First. There is one button that controls the elevator, and it has two values: Up or Down. Also, there are two lights in the elevator that indicate the current floor: Red for Ground, and Green for First. At each time step (clock), the controller checks the current floor and current input, changes floors and lights in the obvious way.