Lecture 2 Sequential Logic Design

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Lecture 2 Sequential Logic Design

• 2007/09/14
• Prof. C.M. Kyung

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Sequential Logic Design

• 1. Experimental GOAL is
• (1) Understanding Principle of Sequential Logic
• (2) Understanding operation of several memory
  elements
• (3) Understanding design process of sequential
  logic

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Sequential Logic Design

• 2. What is sequential logic?
• (1) Output is a function of the current and past
  sequence of input
• (2) Past sequence is stored in the form of
  state
• (3) Memory elements are required (latch,
  flip-flop)

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Sequential Logic Design

• 3. Sequential Logic Implement Step
• (1) Understand the statement of the Specification
• (2) Obtain an abstract specification of the FSM
• (3) Perform a state minimization
• (4) Perform state assignment (or encoding)
• (5) Choose FF types to implement FSM state
  register
• (6) Implement the FSM

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Sequential Logic Design

• 4. Finite State Machine
• (1) Finite number of states
• (2) Finite number of Flip Flops
• (3) Current states by past Inputs are stored

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Sequential Logic Design

• (4) Mealy Machine- Output defined by Input
  current state
• - Asynchronous output
• - Easy to implement in H/W

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Sequential Logic Design

• (5) Moore Machine- Output defined by current
  state

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Sequential Logic Design

• 5. General Machine Concept Ex Vending Machine
• (1) Understand the problem- deliver package of
  gum after 15 cents deposited- single coin slot
  for dimes (10 cents), nickels (5 cents)- no
  change

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Sequential Logic Design

• (2) Draw the Picture

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Sequential Logic Design

• (3) Map into more suitable abstract
  representation- Draw state diagram
• - Inputs N(Nickels), D(Dime), reset
• - Output open

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Sequential Logic Design

• (4) State Minimization

Symbolic State Table
reuse states Whenever possible
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Sequential Logic Design

• (5) State Encoding

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Sequential Logic Design

• (6) Choose Flip Flops for implementation- D
  FF is the easiest to use

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Sequential Logic Design

• (7) Gate Level Implementation

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Sequential Logic Design

• 6. Problem Statement
• (1) Coffee Vending Machine200? ??? ???? ????
  ???? ???? ???? ???? ????. ??? ? ?? ??? 50? 100? ?
  ????? ????? ? ? ? ??? ??. ???? ? ??? ???? ??? ???
  250??? ?????? ??.
• (2) Air Conditioner Controller ???? ?? ??? ????
  ??? ??? ??? ? ?? ?? ??. ??? ???? ?, ?, ?? 3??? ??
  Up, Down? ?? 2?? ??? ??? ? ??. ??? ??? ??? 0? ??
  Down ??? ??? ? ?? ???? ??, ??? ??? ?? ??? Up ???
  ??? ? ?? ??? ??? ???? ???. ?? ?? ??? ?? ??? ??
  ???? ????.

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Sequential Logic Design

• 7. Experiment Requirements
• (1) Equipment - Breadboard- Function Generator
  - DC Power Supply
• (2) Component
• - Switch
• (3) TTL ICs
• - 7400 (2 input NAND gate)
• - 7404 (Inverter)
• - 7408 (2 input AND gate)
• - 7410 (3 input NAND gate)
• - 74LS74 ( Dual D-Type flip-flop )

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Sequential Logic Design

• 8. References
• (1) Textbook
• - Contemporary Logic Design - Katz
• - Fundamentals of Logic Design - Roth
• (2) 2nd Week T.A. E-mail
• jaeuk83_at_gmail.combluewonny_at_gmail.com
• (3) Lecture Homepage
• http//wink.kaist.ac.kr/course/ee306/