Consider a digital combination lock as illustrated in Figure a display that shows the number of keys pressed since the last reset. The lock code below. On its keypad are five digital input buttons for numbers 1-5, a reset button R, and is a sequence of four digits. At the initial state, a 0 is displayed. When a number key is pressed, the display is incremented by 1, regardless of the input. Upon the fourth key press, if the input sequence is correct, the display will change to a 0, unlocking the system. If an incorrect sequence is entered, the display will change to an E upon the fourth key press, and the user must then press the R button to reset the lock to its initial state. The user can also press the R button anytime to reset the lock. Assume that the code is set to 5152. 2 5 3 R CO a) Draw the Moore state machine of the combination lock. b) Draw the Mealy state machine of the combination lock. Hint: consider the display as well as the lock status (locked, unlocked) as the output.