About Digital Design

Digital Design

• Logic Design
• Engineering - Problem Solving
• Debugging -
  • You've already learned some debugging techniques in EE 160. It takes planning, a systematic approach, patience, and logic.
• Risks
  • In EE 160 the risks to bad programming were sometimes not very noticeable. It worked, right?. It might be inefficient or it might be slow but it worked. Sometimes the effects of bad programming can be seen. Take Laulima for example...(That's just a joke UH.)
  • With physical material, you will see risks in design could mean a failure in production. Will i have the part I need? Will I have enough power? Are my clock cycles too fast?

Analog vs. Digital

• We live in an analog world
  • The color intensities of a car
  • voltages, currents in real circuits
  • Numbers like PI exist which cannot be stored on a computer.
• We can often quantize Analog information in order to design digital systems
  • Modern Camera
  • Modern Audio and Filtering
  • Cars
  • Traggic lights
  • Movie Effects
• Analog values are infinitely variable
• Digital color. Maybe you've seen or heard of 256 bit color.
• Digital digits (or bits) often Take on a logic value of 0 or 1
  • This is exactly like the Conditional statements you've seen in programming. True of False.
  • This is called a binary digit or bit.

Note: Assigning 0 and 1 is arbitrary. In this class we will assign 0 as LOW and 1 as HIGH. This is just a more natural assignment and can be thought of as Positive Logic. In Negative Logic, we will assign 1 as LOW and 0 as HIGH

An example of digital logic inverter and truth tables

Inverter truth table (This operation is also known as NOT)

Input Output

0 1

1 0

Inversion is basically the opposite of the input.

Let's say we have a variable name A.

if A = 0

then

A' = 1

A' or Ā - read as A prime or NOT A

Another example

if X = 1

then

X' = 0.

Not X is equal to zero.