Gajski

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GajskiKuhn New VLSI tools

• Y-chart model

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New VLSI tools

• Questions
• May an article from 1983 still be relevant
• May an article about VLSI design tools be
  relevant for you
• Answer
• Yes, if it is used properly as a precondition for
  the relevant domain

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New design tools

• Keywords
• Design methodologies
• Evolutionary bottom-up approach
• Knowledge-based rules top-down approach
• Algorithm-based top-down approach
• Design rules
• From soft to hard guidelines
• Analysis
• Shows if constraints are upheld
• Synthesis
• From constraints to solution
• Quality of result
• Verification
• Description, documentation and communication
• Top-down vs. Bottom-up approaches

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Y-chart model
DataPath ControlPath
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Y-chart model

• Ilustrates that a (VLSI) circcuit may be
  described using
• A set of description domains behaviour,
  structure and layout
• A set of abstraction levels within each domain
• Domain A domain is an aspect of a model which
  can logically be analysed independently from
  other aspects.
• Abstraction An abstraction level defines the
  modelling concepts and their semantics for
  representing a system.The type of information
  available at different levels is different. A
  higher level ignores some irrelevant information
  at a lower level and encodes it using different
  concepts.
• Y-chart is an example of a generic n-dimensional
  description model not limited to
  VLSI-circuitsExamples
• RS232 communication protocol can be described
  using the Y-chart(try)
• OSI-model(why)
• Any SW progam (what is layout in this example)

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Y-chart model

• HW can be described at different levels of
  abstraction
• Abstract mathematics y(n) S h(i)x(i) i
  0..n-1 FIR filter
• Algorithm for i 0 to n-1 y y
  x(i)h(i)
• RTL (Register Transfer Level) y y ab
• Logic level p q xor r s t and u
• For each behavioural domain a corresponding
  structural domain often exists (this is well
  known)

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Y-chart model

• Structural domains are (at decreasing levels of
  abstraction)
• Blockdiagrams
• PMS-description
• RCR-models (ALU, FSM)
• Basic building blocks
• Transistor circuits
• Physical domains are (at decreasing levels of
  abstraction)
• PCB
• Components
• IC-layout
• Mask layout

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Y-chart model

• Y-chart model can be used to define/describe
• analysis/synthesis/simulation/verification
• Constraints versus properties
• Design methodologies
• Computer aided
• Knowledge-based rules
• Algorithmic

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