Bitwise Substraction Circuit

Here's the detailed logic of the bitwise operation of the Hexadecimal Substraction Calculator (http://everycircuit.com/circuit/4556788742225920). The inputs are number A (top left), followed that number B (the result is equal to A-B) and finally the borrow of bit N-1. The upmost LED represents the state of bit N after the operations and the other one represents the borrow of bit N. It's the same circuit as the Bitwise Addition Circuit, with the difference that input A (the upmost logic source) is inverted before entering the AND gates. Here's the truth table of the circuit : A = Bit N of number A B = Bit N of number B C = Borrow of bit N-1 Y = Result of bit N Z = Borrow of bit N ABC-YZ 000-00 001-11 010-11 011-01 100-10 101-00 110-00 111-11

published 6 years ago