QUESTION 3: FINITE STATE MACHINE (10 marks) Consider a turnstile entry control into a subway station or an amusement park: a rotating gate with a coin receiver. There are two possible inputs to the system: inserting a coin and pushing the arm, they can be represented as inputs 1 and 0, respectively. The gate is initially 'locked and will not rotate or allow a passenger to pass through, no matter how many pushes (input 0) are given. The input 1 to the system (coin insertion) changes the state into 'unlocked'. In the unlocked' state any further coin insertion has no effect, whereas a push changes the systenm into the 'locked' state. The output of this system has two possible values: open (1) or close (0) the turnstile, in unlocked' and locked' states, respectively a) (4 marks) Draw a state diagram for the above system. b) (6 marks) Write VHDL code