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Week10

Digital Logic and Computer Architecture

Digital logic: wires, voltage, and values
Basic gates: not, and, or
Others: xor, nand, nor, xnor

Draw truth table for: not, and, or

NOT(0) = 1
NOT(1) = 0

AND(0,0) = 0
AND(0,1) = 0
AND(1,0) = 0
AND(1,1) = 1

OR(0,0) = 0
OR(0,1) = 1
OR(1,0) = 1
OR(1,1) = 1

Others

XOR(0,0) = 0
XOR(0,1) = 1
XOR(1,0) = 1
XOR(1,1) = 0

NAND(0,0) = 1
NAND(0,1) = 1
NAND(1,0) = 1
NAND(1,1) = 0

NAND(x,y)  = NOT(AND(x,y))

Draw OR (sum) notation and AND (product) notation. Explain notation.

Use basic gates to build more complex functions.

Such functions are combinational (as opposed to sequential)

Gates are now made out of transistors. 

Moore's law Number of transistors doubles every 2 years: http://en.wikipedia.org/wiki/Moore's_law







Combinational logic

Truth tables

Sum of products

1-bit half adder

1-bit full adder
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