CSCI 255 — Finite State Machine implementation

This lab gives you a head start on Homework 4.

In the lab and homework, You will take a FSM from a diagram to an implementation in logisim. The FSM has one input and one output. It will output a 1 only when the preceding four input values are 1011. Here’s a FSM diagram.
hand drawn FSM

Task 1 — The table specification

In this part of the lab assignment, you will create three tables describing the FSM. I strongly suggest your start with the spreadsheet specification of the Nabs FSM that we used in class and make the necessary modifications. This spreadsheet already contains the three tables.

  1. The state transistion table in “English”
  2. The binary encoding of the FSM states. Because this FSM has five states, you will need three bits to encode the states.
  3. The state transistion table as a truth table. You will need to modify the truth table because the states of this FSM are implemented with three, rather than two, bits and the inputs and outputs of this FSM are one, rather than two, bits.

Task 2 — The circuit implementation

Now implement your FSM as the circuit level using logisim. Start with the solution to the Fall 2015 homework discussed in class. Try to make a minimum number of alterations.

Now what

Hopefully, you have a good start on Homework 4 to turn in next week.