How can I modify the state machine logic?

I'm working on this RTOS-based application for a vending machine controller with

and a state machine approach that manages various vending machine states as

Idle

Idle

CoinInserted

CoinInserted

SelectionMade

SelectionMade

Dispensing

Dispensing

, but
I'm encountering an error message in the console:

StateMachine Error: Invalid transition from CoinInserted to Dispensing.

StateMachine Error: Invalid transition from CoinInserted to Dispensing.

This occurs when a user inserts enough coins to trigger dispensing, but the selection hasn't been confirmed yet.

typedef enum {
  STATE_IDLE,
  STATE_COIN_INSERTED,
  STATE_SELECTION_MADE,
  STATE_DISPENSING
} VendingMachineState;

typedef struct {
  VendingMachineState currentState;
} VendingMachine;

extern VendingMachineState GetCurrentState(VendingMachine *machine);
extern void SetNextState(VendingMachine *machine, VendingMachineState nextState);

typedef enum {
  STATE_IDLE,
  STATE_COIN_INSERTED,
  STATE_SELECTION_MADE,
  STATE_DISPENSING
} VendingMachineState;

typedef struct {
  VendingMachineState currentState;
} VendingMachine;

extern VendingMachineState GetCurrentState(VendingMachine *machine);
extern void SetNextState(VendingMachine *machine, VendingMachineState nextState);

How can I modify the state machine logic to prevent this invalid transition and ensure a valid sequence of states

Idle -> CoinInserted -> SelectionMade -> Dispensing

Idle -> CoinInserted -> SelectionMade -> Dispensing

ZacckOsiemoAPP•6/12/24, 4:43 PM

I think you would need to show your logic for any opinions

Boss ladyAPP•6/12/24, 4:44 PM

Hi @Marvee Amasi to prevent the invalid transition from CoinInserted to Dispensing when the selection hasn't been made yet, you can modify the state machine logic to introduce an intermediate state between CoinInserted and SelectionMade.

your code for the enum should be