Download NO MEMORY. AS SOON AS INPUT IS GIVEN (after a brief delay

ITEC 352
Lecture 3
Low level components(2)
Review
•
•
•
•
Electricity
Transistors
Gates
Really simple circuit
Low-level
components
Review
• What are
Low-level
components
Review #2
• What does this turn into?
Low-level
components
Review 3
• What does this do?
Low-level
components
Truth
tables…
• Draw the truth tables for the following
functions:
• F = A’B’C + A’B’C (here the ‘ stands for
bar).
• F = A’B + B’A
Low-level
components
Digital
Circuits.
• Consider the following digital circuit.
• Express it as a Boolean algebra expression.
– i.e., F = …? (in terms of A, B, C)
– G = …?
Low-level
components
More
Find the boolean expression
Can you optimize it?
Low-level
components
Combination
al Logic
• Circuits formed using gates.
– Key issue: no memory is used in building
these circuits.
Low-level
components
Logic Unit
•
Translates a set of inputs into a set of outputs
•
The outputs of a CLU are strictly functions of the inputs, and the outputs
are updated immediately after the inputs change.
– NO MEMORY. AS SOON AS INPUT IS GIVEN (after a brief delay due to the
propagational delay) THE OUTPUT SHOWS UP.
Low-level
components
Example circuit
Multiplexer: Determines which input will
reach output
Low-level
components
Uses of a
MUX
• Routers, Switches Etc…
• To implement different other functions.
• Multiplexers can be joined together easily.
– E.g., Join two 4 X 1 mux’s to get one 8 X 1 mux.
• Example:
– Implement the majority function using a Multiplexer
Low-level
components
Summary
• Boolean algebra
• Truth tables
• Mux
Low-level
components