VLSI Design Testing and Fabrication

Abdulah Alshafi

Outline

Introduction

Design Structured Design

Design Abstractions

Y-chart of Design partitioning

MIPS Architecture and Micro-architecture

Logic Design

Circuit Design

Physical Design

Design Verification

Fabrication

Introduction

Companies use hundreds of millions or sometimes billions of transistors which cost tens of millions of dollars or more to design. Talent - materials, devices, hardware designers,

software designers, mechanical engineering, chemical engineering, business (marketing, sales)

Complexity - hardware design, software design, test design, tools for fabrication and test

The greatest challenge in VLSI design is not in designing the individual transistors but rather managing the system complexity

Design

Structured Design Hierarchy

○ Partitioning a large system into multiple cores for units of functional blocks to cells which are constructed from transistors

Regularity

○ Aids the minimum number of different blocks for better design complexity management

Modularity

○ Defining interfaces between blocks to avoid unanticipated interaction

Locality

○ inputs and outputs are physically and temporally close

Design

Design Abstractions Architecture design

○ Describes the functions of the system

Microarchitecture design○ Describes how the architecture is partitioned into

registers and functional units

Logic design○ Describes how functional units are constructed

Circuit design○ Describes how transistors are used to implement

the logic

Physical design○ Describes the layout of the chip

Design Y-chart of Design partitioning

Y- chart design domains

Behavioral domain

Describes what a particular system does

Structural domain

Describes the interconnection of modules

necessary to achieve a particular behavior

Physical domain

Describes how to physically construct each

level of abstraction

MIPS Architecture

MIPS (Microprocessor without Interlocked Pipeline Stages) is a reduce instruction set computer (RISC) developed by MIPS Computer Systems (now MIPS Technologies).*

MIPS is a 32-bit architecture with 32 registers Consider 8-bit subset using 8-bit datapath

Only implement 8 registers ($0 - $7)

$0 hardwired to 00000000

8-bit program counter

The MIPS also have later versions were 64-bit. *

*//en.wikipedia.org/wiki/MIPS_architecture

*//www.cs.cornell.edu/courses/cs3410/2008fa/MIPS_Vol1.pdf

Instruction set

MIPS32 Architecture templates

MIPS32 Program C code for Fibonacci program

MIPS32 Program Translated to assembly language

MIPS32 Program Translated to machine language

MIPS32 Microarchitecture

MIPS32 Controller FSM state

transition diagram

Logic Design

Top-Level interfaces

Block diagrams

Hierarchy

Hardware Description languages

Top-Level interfaces

Block Diagrams Top-level MIPS block diagram

Block Diagram

8-bit datapath viewed as

Wordslice

Bitslice

Hierarchy

Hardware Description Languages (HDL)

Two most popular HDLs

Verilog

VHDL

Structural HDL

Specifies how a cell is composed of other

cells or primitive gates and transistors

Behavioral HDL

Specifies what a cell does

Circuit Design

Physical Design

Floorplanning

Standard Cells

Pitch matching

Slice Plans

Illustrates the ordering of wordslice and the

allocation of wiring each bitslice

Arrays

Area Estimation

Floorplanning

Actual chip layout

Standard Cells

Standard Cells

Pitch Matching

Pitch Matching MIPS Datapath

Slice Plans

Arrays

Area Estimation Need area estimates to make floorplan

Compare to another block you already

designed

Or estimate from transistor counts

Budget room for large wiring tracks

Your mileage may vary!

Design Verification

Fabrication,

Packaging & Testing