UPC EETAC Bachelor's Degree in Telecommunications Systems and in Network Engineering EEL

Chapter 1 problems

      - D1.6 -

8-bit demultiplexer




1. Specifications

Design a DeMUX_8 similar to the classic 74HCT138 chip in a programmable logic device (PLD) target chip. The circuit symbol and its truth table is represented in FIg. 1.

Symbol DeMUX_8

Fig. 1. DeMUX_8 symbol and truth table. Select channel input S(2..0) is defined as vector.

As theory, explain what kind of applications will use DeMUX, and what may be input data D.


2. Planning

Plan A using our VHDL design flow using logic equations and EDA tools for developing and testing.


Plan B capturing in VHDL the truth table.


Plan C2 hiearchical circuit using DeMUX_4 components.