Lecture
2.4
Approaches to
design entry
Paolo PRINETTO
Politecnico di Torino (Italy)
University of Illinois at Chicago, IL (USA)
[email protected]
[email protected]
www.testgroup.polito.it
Goal
 This lecture introduces the approaches used,
during the overall design cycle, to capture the
information items related to the design itself, in an
Electronic Design Automation (EDA) system.
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2
Homework
 No particular homework is foreseen
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3
Prerequisites
 Lecture # 2.3
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4
Further readings
 No particular suggestion
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5
Design entry
Design Entry (or Design Capture) is the set of steps to
go through to enter a design description into an EDA
system.
Design
entry
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6
Description translation
Description
Libraries
Compiler
Design
Data Base
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Approaches
Design
entry
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8
Approaches
Textual
Design
entry
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Approaches
Textual
Graphic
Design
entry
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10
Approaches
Textual
Graphic
Design
entry
2.4
Based on
ad-hoc
graphical
languages
11
Classification
Abstraction
levels
system
RT
logic
device
behavior
2.4
structure
physical
Representation
domains
12
Classification
High Level
Graphical
Languages
Abstraction
levels
system
RT
logic
device
behavior
2.4
structure
physical
Representation
domains
13
High Level
Graphical Languages
Last generation languages that allow the designer to
describe the system structure and/or behavior in
terms of:
 concurrent processes
 state transition diagrams
 flow-charts
 blocks interconnections
 …
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Example: Statemate
SYSTEM
POWER_ON
OFF
ON
RESET
WAIT_CMD
EXECUTING
READ_DATA
EXECUTE
A
PROCESS_DATA
Y
B
2.4
POWER_OFF
Z
15
Classification
Abstraction
levels
system
RT
logic
device
behavior
2.4
structure
physical
Representation
domains
16
Classification
Schematic
editors
Abstraction
levels
system
RT
logic
device
behavior
2.4
structure
physical
Representation
domains
17
Schematic Editors
They represent the “traditional” tools to represent
system structure in terms of blocks and modules
interconnections.
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Example
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Example of
hierarchy
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Example of
hierarchy
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Example of
hierarchy
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Pro’s & Con’s
 Easily to use
 Low productivity
 Applicability restricted to the structural domain,
only.
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Status
 In 1991, the 85% of industrial designs was based
on schematics
 Today, most industrial designs are based on
 VHDL
 Verilog
 C++
 Java
 ...
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24
Classification
Abstraction
levels
system
RT
logic
device
behavior
2.4
structure
physical
Representation
domains
25
Classification
Abstraction
levels
Layout
tools
system
RT
logic
device
behavior
2.4
structure
physical
Representation
domains
26
Layout tools
 Used today mostly to develop cells libraries
 Basis
elements
are
usually
symbolically (symbolic layout tool).
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represented
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Example
+V
+V
MP
IN
OUT
MN
GND
GND
[P.L. Civera]
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Approaches
Textual
Graphic
Design
entry
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Approaches
Textual
Graphic
Based on ad-hoc
programming languages,
particularly tailored to the
descriptions of digital
systems:
Design
entry (Hardware Description
Languages or HDL)
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Problems in Hardware
description
 Hierarchy
 Concurrency
 Communications among modules
 Timing
 Propagation delays
 Different domains and abstraction levels
 Technology peculiarities
 Constraints descriptions
 …
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Application areas
Abstraction
levels
system
RT
logic
device
behavior
2.4
structure
physical Representation
domains
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Pro’s & Con’s
 Allow mixed-level (system, RT, logic, device) and
mixed-domain (behavior, structure, physical)
descriptions
 Feed EDA & Synthesis tools
 Allow a “natural” design documentation
 Standards exist (e.g., VHDL, Verilog)
 Dramatically improve productivity
 Are usually harder to learn than schematic
editors.
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