This is the main circuit in logism;

which has 2 keypads 3 hex digit displays. The displays show the numbers enters on keypad 1 and keypad 2 and the contents of the DR register. A switch for carry-in to is connected to the Add component. LED shows if there is a carry-out from the addition operation. 3 LEDs that indicate if the result is ZERO, NEGATIVE or POSITIVE. 1 push button for clock. 1 push button for reset.

i need help building the ALU sub Circuit (in the program logism), it consists of:

4 bit input pins for keypad1, keypad2 and a 4 bit output bin for result. 1 bit input pins for clock, rese, carry-in and a 1 bit output pin for carry-out. 3 registers. Each 4 bits wide. Label them SR1, SR2 and DR. The registers need to connect to the RESET and CLOCK push buttons. An adder component with data width 4 bits. The adder component has carry in and carry out signals. Use the Adder component from Logisim.

To operate the circuit you push the CLOCK button two times. Why two times? The first clock pulse will store the values of keypad 1 into register SR1 and keypad 2 into SR2. The second clock pulse will store the output of the adder into DR. Can you figure out a way to do the addition with only one clock pulse?

..Carry out 0 1 2 3 4567 8 9 A B C D E F (OFF O OFF Carry in 4 5 6 0123 45675 8 9 A B CDEF .clock 'reset Figure 1 main circuit ..Carry out 0 1 2 3 4567 8 9 A B C D E F (OFF O OFF Carry in 4 5 6 0123 45675 8 9 A B CDEF .clock 'reset Figure 1 main circuit