65. Ripple Carry Adder
Add two 4-bit unsigned numbers with a carry-in, using a ripple-carry chain of four 1-bit full adders.
Requirements
- Top Module:
rca4_chain - Inputs:
a[3:0],b[3:0],cin - Outputs:
sum[3:0],cout - Implement a 1-bit full adder module
full_adder_1bitand instantiate 4 of them. - Connect carries as
c0=cin → c1 → c2 → c3 → c4=cout. - Keep it fully combinational.
Behavior
- Inputs:
a[3:0],b[3:0],cin - Outputs:
sum[3:0],cout - Equation:
{cout, sum} = a + b + cin