Connecting a 4-bit adder to a 1-bit adder
Posted on 2004-03-21
How do you connect a 1-bit full adder (designed with 9 NAND gates) to a 7483 (4-bit adder)?
I'm having problems with it working 100 percent.
1. Built the 1-bit adder (A,B,Cin); (S,Cout) , tested with the truth table; worked flawlessly.
2. Connected the 7483, making the 1-bit adder the higher-order bit. I grounded the Cin of the 7483, connected the Cout to the Cin of the 1-bit adder, connected the all Sums to leds, and A&B's to switches.
Some sums are incorrect:
(10011)+(10111) does not = 1 01010
(11111)+(11111) does not = 1 11110
What could I do to make this 5-bit adder work?