#FINITE STATE AUTOMATA COIN CODE#
However, as the number of states or events grow, the code can easily go unwieldly. When the number of states and events is few, this method is intuitive and developers get a quick picture of what the state machine is doing. Using conditional statements is an extremely simple approach to get the implementation started. If there is a state change involved, the handler returns the new state.Ī sample implementation for the state machine is shown below. Alternatively, we could swap the order and check the event first and then the state.
A handler is then added for that state/event combination. Within each state, another conditional statement is added to check the event triggered. A switch-case statement or if-else statement is used to check each state. There are two common approaches for implementing an event based state machine like the one above: Additional events like debug timer expiry signal could be added.įigure 1 Sample state machine for a coffee vending machine (Source: The author) The system waits on user inputs and signals from the coffee dispensing unit. In this article, we will look into the different approaches for implementing state machines using C.įigure 1 shows a sample state machine for a coffee vending machine. The event could be due to an interrupt in the system, an RTOS signal, a timer expiry indication or an input or indication from another module in the system. At any point of time, the system is in one state and an event triggers certain actions in that state along with a possible change in state. The finite state machine is made up of multiple states. Many applications from simple home appliances to complex communication systems implement event based state machines. A finite state machine is one of the most popular design patterns in embedded systems.
0 kommentar(er)
