An electronic lock using a keypad for authentication is to be designed for the Department of Computer and Communication Systems Engineering general office. There are three buttons, coloured Red, Green and Blue and a fourth button Start for starting the code on the keypad. To unlock the door, a person is required to press the Start button followed by the sequence - Red, Blue, Green, Red. Any other sequence will keep the door locked. The keypad has an additional output a, which will be 1 (HIGH) for exactly one clock cycle when any button is pressed, no matter how long the button is pressed. The system block diagram is shown in Figure 3. (a) (b) (c) Design the code detector circuit for the keypad-protected door by constructing the Moore model state diagram. Show the implementation of the circuit using FPGA by writing the Verilog code including its test bench. Provide an active high asynchronous Reset in your design. Based on your design, what would happen if a user pressed the Start button and then pressed all three coloured buttons simultaneously, four times in a row? Justify your answer. Start U Red Door Green Code g detector lock b Blue (Figure 3)