Modeling and Simulation of a Vending Machine Through FSM Using VHDL

Currently, vending machines are evolving as one of the main modes of automatic shopping and easy access to products by users. This work aims to simulate two types of Moore and Mealy state machines based on the concept of finite state machines (FSM) to dispense chocolate products, allowing the input of three-coin values. The vending machine was developed using the VHDL (Very High-Speed Integrated Circuits) program and simulated with Quartus ModelSim-Intel software for both Moore and Mealy machines. For the model design, two states were used, such as money insertion and product delivery. Simulation results show the comparisons of state timing diagrams and RTL diagrams for both states, where the Moore machine needs more states to deliver the product, and the response is slower, while the Mealy machine needs fewer states to provide the product; therefore, the response is faster.