Building ALU based 4-bit addition using two 74SL 74 (4 D FF's) and a 4-bit adder: • Build "a 4-bit Register out of D flip-flops. It should have the basic Clear pulse switch to clear the data and the Clock pulse switch input to give a clock pulse to the D flip-flop indicating the change of state. In this case, we have one input switch connected to input if each D flip-flop. All four outputs of the D flip-flops are connected to the 4 LEDs. For this online version: • Go to the Memory folder, and drag over 4 D Flip Flops. Label these flip-flops Bit 0, Bit 1,Bit 2,Bit 3. • Go to the Input/Output folder, and drag over one button. Label this clock, and connect it to each flip-flop. Go to the Input/Output folder, and drag over one button. Label this Clear, and connect it to each flip-flop. Go to the Wiring folder, and drag over four Pins. Connect these to the D of each D-Flip-Flop. Label these DO, D1, D2, and D3. • Go to the Input/Output folder, and drag over 4 LEDs and connect one to the of each flip flop. Extend this implementation to perform the following ALU addition operation. Add A, B - This operation adds A and B and stores the result in A. This 4-bit register acts as an accumulator. This accumulator is connected with an adder and is performing the following task. The initial value of the accumulator is 0 and every time a clock pulse is given, it adds the current value of the accumulator (let's call it A) and a given 4-bit input B. The B input is provided using 4 input switches. Thus, the accumulator stores the addition of multiple 4-bit values provided to the ALU. For this online version: • Drag and drop 4 Adders from the Arithmetic folder. Set each adder to be 1 data bit in the properties. Connect htem to make a 4-bit full adder. Drag and drop 4 input pins from the Wiring folder. Label these pins BO, B1, B2, and B3. • Drag and drop 4 D flip-flops from the Memory folder. Label these flip-flops AO, AI, A2, and A3. Drag and drop 1 input pin from the Wiring folder. Label this pin "Carry In" Drag and drop 4 LEDs from the Input/Output folder. Attach one to each of the Q output of the 4 flip flops. Drag and drop 1 LED from the Input/Output folder. Connect this LED to the last carry of your 4-bit adder. • Implement the circuit.