## How do you write a finite-state machine in Verilog?

Basically a FSM consists of combinational, sequential and output logic. Combinational logic is used to decide the next state of the FSM, sequential logic is used to store the current state of the FSM. The output logic is a mixture of both combo and seq logic as shown in the figure below.

### What is finite-state machine in Verilog?

Finite State Machines (FSM) are sequential circuit used in many digital systems to control the behavior of systems and dataflow paths. Examples of FSM include control units and sequencers. This lab introduces the concept of two types of FSMs, Mealy and Moore, and the modeling styles to develop such machines.

**What is a state machine in Verilog?**

A state machine is a sequential circuit that advances through a number of states. By default, the Quartus II software automatically infers state machines in your Verilog HDL code by finding variables whose functionality can be replaced by a state machine without changing the simulated behavior of your design.

**Which of the following are the examples of finite state machine system?**

There are many more examples of finite state machines we could use:

- a vending machine.
- a subway entrance turnstile.
- a heating system.
- an automated subway system.
- a self-driving car system.
- an elevator.

## What is pound in Verilog?

1. It’s a delay operation. It essentially just reads always begin #(cycle/2) //wait for cycle/2 time clk ~= clk; end. You might sometimes see this used with raw values, like #5 or #10, which means to wait 5 or 10 units of your timescale.

### What does timescale 1ns 1ps mean?

`timescale 1ns/1ps means that all the delays that follow (like# 5.1234) are interpreted to be in nanoseconds and any fractions will be rounded to the nearest picosecond (5123ps). However, all delays are represented as integers. The simulator knows nothing about seconds or nanoseconds, only unit-less integers.

**Is there a Verilog test for the Moore FSM?**

A Verilog Testbench for the Moore FSM sequence detector is also provided for simulation. The Moore FSM keeps detecting a binary sequence from a digital input and the output of the FSM goes high only when a “1011” sequence is detected. The state diagram of the Moore FSM for the sequence detector is shown in the following figure.

**When does the output of the Moore FSM go high?**

Next state of the Moore FSM depends on the sequence input and the current state. The output of the Moore FSM only depends on the current state. The output of the sequence detector only goes high when the “1011” sequence is detected.

## What are the two types of finite state machines?

A finite state machine can be divided in to two types: Moore and Mealy state machines. Fig. 1 has the general structure for Moore and Fig. 2 has general structure for Mealy. The current state of the machine is stored in the state memory, a set of n flip-flops clocked by a single clock signal (hence “synchronous” state machine).

### Where is the current state stored in a FSM?

The current state of the machine is stored in the state memory, a set of n flip-flops clocked by a single clock signal (hence “synchronous” state machine). The state vector (also current state, or just state) is the value currently stored by the state memory.