4 bit binary adder circuit discussion with example. Half-adder, full-adder,adder-subtractor, verilog
4 bit binary Adder introduction:-Binary adders are implemented to add two binary numbers. So in order to add two 4 bit binary numbers we need to use 4 full-adders. The connection of full-adders to create binary adder circuit is discussed in block diagram below. In this implementation, carry of each full-adder is connected to previous carry. Detailed discussion on full-adder is covered on this link.
Example Lets discuss one example for 4 bit binary Adder. In this example we will use some terms from Register Transfer Level (RTL) implementations. Question: Add two binary numbers 7 and 15 with previous carry = 0. Solution: Load the values in two registers R1 and R2. So, R1 = 7 (decimal) = 0111 (in binary A3A2A1A0) & R2 = 15 (decimal) = 1111 (in binary B3B2B1B0) So from the above implementation we have -
Augends bits A
Addend bits B
Sum of two binary numbers 7 and 15 from above table Is C4S3S2S1S0 = 10110 (In Binary) = 16 (decimal)