ECE 275: Common building blocks


\[ \newcommand{\bx}{\bar{x}} \newcommand{\by}{\bar{y}} \newcommand{\bz}{\bar{z}} \newcommand{\bA}{\bar{A}} \newcommand{\bB}{\bar{B}} \newcommand{\bC}{\bar{C}} \newcommand{\bD}{\bar{D}} \newcommand{\bE}{\bar{E}} \]


  • Homework 5 is due on Oct 15th, 9 AM before class.

Design a 4-bit Adder/Substractor unit

Using an adder and 1's complement unit.

Adder/Substractor unit

Gray code

Gray code

Binary Coded Decimal

Binary Coded Decimal

Common building blocks of digital circuits

  • Multiplexers
  • Decoders/Encoders
  • Three state buffers

Recall 2-to-1 Multiplexer (MUX)

Telephony multiplexing

More Multiplexers (MUX)

More Multiplexers (MUX)

\[ Z = \bA \bB I_0 + \bA B I_1 + A\bB I_2 + AB I_3 \] \[ Z = \bA \bB \bC I_0 + \bA \bB C I_1 + \bA B \bC I_2 + \bA B C I_3 + A \bB \bC I_4 + A \bB C I_5 A B \bC I_6 + A B C I_7 \] \[ Z = \sum m_k I_k \]

Sample application: data routing

Quad 2-to-1 MUX

Three state buffers

Sample applications: Bi-Directional IO

2-to-4 Decoders

2-to-4 Decoders

3-to-8 Decoders

2-to-4 DeMUX


Priority Encoder

Sample application: ROM

Thanks, Questions, Feedback?