Digital Logic

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Digital Logic

• ELET 1133
• Grading
• Whats Digital?

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Introduction

• ROLL CALL!

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Digital Logic is all 0s and 1s

• If you know nothing you already know half the
  course.

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Introduction

• Review course information handout.

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Study Required

• 1 hour lecture
• plus
• 2-3 hours self study
• equals probable success.

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Digital Vs. Analog

• Analog
• Continuous in time.

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Analog Examples

• Typical sounds, human hearing.
• Most natural phenomenon.
• Temperature.
• Pressure.
• Speedometer (typically).
• Other examples from class.

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Digital

• Discrete in time.
• At a fixed time interval assign a step value.

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Digital Examples

• Analog vs. Digital watches.
• How many have which?
• Steps verses an analog ramp.
• Digital multimeter.
• Growth rings on a tree.
• Data transmission.
• Other examples from class.

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Digital Logic

• Achieve the desired output(s) using a
  combination of several two-state inputs.

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Digital Logic Block Diagram
Processor (Logic)
Outputs
Inputs
What you have.
What you want.
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Binary

• A digital system based on two discrete states
  is binary.
• A state is a possible condition.
• State where the solution can live.

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Math in Digital Logic

• Only need to count to one.
• Then start over.
• There is a math system specifically to handle
  binary operations.

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Binary Coding States

• Examples?
• Telegraphy c. 1840 (Morse code).
• Short or long (uses space also).
• Teletype.
• Current or no current called mark and space.
• Audio transmission of digital.
• Low frequency or high frequency.

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Coding States

• Compact disc.
• Transitions between pits and surface.
• Numerical representation.
• Zero or one.
• Switch logic.
• Open or closed contacts.
• Transistor logic.
• 5 volts or 0 volts.

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Binary Coding

• Bit one binary digit.
• A one or a zero is a bit.
• Byte 8 bits.
• 01011100.

high low
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Example

• Nail gun.
• Paslode impulse compact utility framing nailer.
• Description of operation.

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Nail Gun Outputs

• 1. Nail ejection.
• If all inputs are okay.
• 2. Cooling fan.
• Runs if a nail is ejected.
• 3. Battery status.
• Continuous monitoring. Green light then okay.
  Red light then battery low.

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Nail Gun Inputs

• Nails AND
• Battery AND
• Fuel Cell AND
• Safety interlock AND
• Trigger
• all these have two states either okay or not
  okay.
• If all okay, a nail is discharged.

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Digital Logic Example

• Breadmaker Board
• Inputs
• push buttons
• temperature sensor
• clock
• Outputs
• relay to motor
• LCD panel
• LEDs
• buzzer

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(Approximate) Logic Implementation Family Tree