Tools

Combinational Logic Design            

Assignment Statements :

  • Create a half adder circuit using only logic gates and test it by giving proper input.
  • Create a full adder circuit using only logic gates and test it by giving proper input.
  • Create a full adder circuit using half adder and test it by giving proper input.
  • Create a 4-bit ripple carry adder circuit using half adders and full adders and test it by giving proper input.

Circuit diagram of Ripple Carry Adder:

Procedure

  • To draw any diagram in the simulator please follow the manual given in manual section.
  1. Half Adder with ‘XOR’ and ‘AND’ gates readily available in the simulator.
where

20, 21: Input bits

26: Sum

27: Carry

  • This could be saved as a component with suitable name – say ‘HalfAdder’.
  1. Full Adder with ‘XOR’, ‘AND’ and ‘OR’ gates readily available in the simulator.

where

82, 83: Input Bits

84: Carry-In

85: Sum

87: Carry-Out

  1. Full Adder with the help of Half Adders (Designed Above) and ‘OR’ gate
where

1, 15: Half Adders

62, 63: Input Bits

64: Carry-In

65: Sum

66: Carry Out

  • This could be saved as a component with suitable name – say ‘FullAdder’.
  1. Ripple Carry Adder with 1 half adder and 3 full adders
  • 1: Half Adder and 15, 52, 89: Full Adder
  • First 4 bit number represented by 183(LSB), 185, 187 and 189(MSB) and second 4 bit number represented by 184 (LSB), 186, 188, 190 (MSB).
  • The output number after sum is 191 (LSB), 192, 193, 194 (MSB).
  • Final carry-out is 195.

Follow the below manual and perform the experiment