Design adders & shift register


  <1> implement a half-adder as a device 
  <2> use this half-adder to create a full-adders 
  <3> implement a full adder as a device 
  <4> use the full adder device to implement a 4-bit parallel adder 
  <5> implement a 4-bit shift register device


Lab Assignments

  1. Following the notes in the lab, you should have completed the half adder device.
    Use the device (the box) and connect binary probes and switches to ensure that the truth table is correct.
    Write the boolean functions for sum and carry beside the circuit


  2. As mentioned in the notes, a full adder can be designed using two "Half Adder" devices and one additional gate.
    (Hint ci+1= the sum of the carries out of the two half adders).
    Build and test your circuit with the truth table.
    Write the boolean functions for sum and the carry beside the circuit.
    Build a full adder device and test it. You will need it to build a 4-bit parallel adder.


  3. Build a 4-bit parallel adder device by using four "Full Adder" devices.
    For this, you will use the "Full Adder" device that you just built in the last step.
    Test your 4-bit parallel adder device with the following examples:
    	  0101 + 0010 = ?
              0110 + 0011 = ?
              and any other examples of your choice


  4. Build a 4-bit shift register device using four D-flip-flops and four multiplexers (MUX-4).
    Make sure that you have selection inputs control over it.
    	Select Inputs	Function
    	S1	S0			 
    	0	0	Store
    	0	1	Shift left
    	1	0	shift right
    	1	1	Load

    Here is the design diagram for you:


Copyright: Department of Computer Science, University of Regina.