(Word Problem) Your task is to design the control for a newspaper vending machine to the f...

(Word Problem) Your task is to design the control for a newspaper vending machine to the following specification. The newspaper costs 50 cents. The vending machine accepts nickels, dimes, and quarters. The customer presses a START button and then begins entering coins. Coin sorter logic indicates to the FSM whether a nickel (N), clime (D), or quarter (Q) has been deposited. (Assume that the FSM advances from one state to the next when a coin is deposited.) If exact change is entered, a latch is released so the customer can get the paper. If the amount of money deposited exceeds 50 cents, the deposited coins are refunded to the customer by asserting a refund (REF) signal. Assume that the money just deposited is kept separated from previously accepted coins. The latter are held in a coin repository. Otherwise, the deposited coins join the repository as the FSM asserts a release (REL) signal. The block diagram for the FSM is shown in Figure 1.

Consider for a moment the signals that indicate the number of nickels and dimes available to make change. What is the maximum number of nickels needed at any time? What is the maximum number of dimes needed? Understanding the answers to these questions may help to simplify your state diagram.

Complete a Mealy machine state diagram for the vending machine’s control.

Figure 1

Inputs/outputs for newspaper vending machine.