Ripple Carry Adder adds 2 n-bit number plus carry input and gives n-bit sum and a carry output. The Main operation of Ripple Carry Adder is it ripple the each carry output to carry input of next single bit addition. Each single bit addition is performed with full Adder operation (A, B, Cin) input and (Sum, Cout) output. The 4-bit Ripple Carry Adder VHDL Code can be Easily Constructed by Port Mapping 4 Full Adder. The following figure represent the 4-bit ripple carry adder.