Finite State Machines [High Level Design]

Question 1

Draw the RTL diagram for a Class-1 FSM.

Answer 1

Codeword feed-forward only

Question 2

Draw the RTL diagram for a Class-2 FSM.

Answer 2

Codeword feedback, output without external input

Question 3

Draw the RTL diagram for a Class-3 FSM.

Answer 3

Codeword feedback, external input

Question 4

Draw the RTL diagram for a Class-4 FSM

Answer 4

Codeword feedback, external input, I/O bypass

Question 5

How can we build larger scale (potentially many input) FSMs?

Answer 5

Using modularity and linking several FSMs. They are all synchronised by having a common clock signal.

Question 6

How do you represent a state in an ASM chart?

Answer 6

A rectangle containing the active outputs with an ellipse to the top left containing the state name.

Question 7

How do you represent a transition decision in an ASM chart?

Answer 7

With a diamond box containing the variable (input) and a path for each outcome 0 or 1.

Question 8

How do you represent a simple state-to-state transition in an ASM chart?

Answer 8

A simple arrowed line

Question 9

What is modulation in FSMs?

Answer 9

We can split a problem into several FSMs (represented by ASM charts) connected by an output/input pair.