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Computing Machinery Chapter 3: Combinational Circuits. Half Adder. Full Adder. Full Adder Circuit. s = a b c in. +. +. Simplifying the Full Adder Circuit. C out = ab + ac in + bc in. N-Bit Adder. Ripple-Carry Adder. Carry Look-Ahead Adder (CLA). c in. a i. b i. g i = a i b i
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Computing Machinery Chapter 3: Combinational Circuits
s = a b cin. + + Simplifying the Full Adder Circuit Cout = ab + acin + bcin
Carry Look-Ahead Adder (CLA) cin ai bi gi = aibi pi = ai + bi ci+1 = gi + pici 1. Will ith FA generate a carry bit? 2. Will ith FA propagate a carry bit? 3. What is the carry-out for the ith FA? ith FA ci+1 si
Binary Coded Decimal (BCD) Encoder Function Table
3-to-8 Decoder (aka 1-of-8)
Implementing a Boolean Function using an Decoder F(x,y,z) = m( 1, 2, 5, 7 )
Implementing a Boolean Function using a Multiplexer G(x,y,z) = m( 1, 4, 5, 6 )