Ch.9 CPLD/FPGA Design

TAIST ICTES ProgramVLSI Design Methodology

Hiroaki Kunieda

Tokyo Institute of Technology

2

Outline

1. CPLD & FPGA2. Design Procedure

9.1 Programmable Device

4

FPGA

Reconfigurable LSI or Programmable Hardware

Programmable Logic Array and Programmable Interconnection

Programmed by Reconfigurable Data Xilinx and Altera Prototyping of ASIC (different physical

condition)

ECE 545 – Introduction to VHDL

The Programmable MarketplaceThe Programmable MarketplaceQ1 Calendar Year 2005

Source: Company reportsLatest information available; computed on a 4-quarter rolling basis

XilinxXilinxAltera

LatticeActel QuickLogic: 2% XilinxXilinx

All OthersAll Others

Two dominant suppliers, indicating a maturing market

PLD Segment FPGA Sub-Segment

Other: 2%

51%33%

5% 7%

AlteraAltera

58%

31% 11%

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FPGA families

Spartan 3 Virtex 4 LX / SX / FX Spartan 3E Virtex 5 LX

Spartan 3L

Low-cost High-performance

Xilinx

Altera Cyclone II Stratix II

Stratix II GX

Xilinx and Altera FPGA

Xilinx #gates Program

Clock Note

Virtex 50k-10M SRAM 550MHz System

Spartan 5k-300k SRAM 250MHz ASIC

XC9500 13k-85k SRAM 100MHz

Altera #gates Program Clock Note

Stratix 180k SRAM 500MHz High end RAM & Multiplier

Cyclone 16k SRAM 200MHz Low cost

FLEX 10k-250k SRAM 200MHz High Speed

MAX(CPLD)

600-10K EEPROM 150MHz Low Price

9.2 PLD

9

ＣＰＬＤ

Function Block in CPLD

Example of PLD Design

S １　 S ２　 S ３ X

S １ S ２　 S３　 Y

0 0 0 0 0 0 0 0

0 0 0 1 0 0 1 0

0 0 1 * 0 1 1 0

0 1 1 * 1 1 1 0

1 1 1 * 1 1 0 0

1 1 0 * 1 0 0 0

1 0 0 * 0 0 0 1

000

001

011

111

110

100

X=0

X=1State Transition Table

Y=1

PLA & FF Realization

S １　 S ２　S ３　 X

DS １ DS ２　 DS３　 Y

0 0 0 0 0 0 0 0

0 0 0 1 0 0 1 0

0 0 1 * 0 1 1 0

0 1 1 * 1 1 1 0

1 1 1 * 1 1 0 0

1 1 0 * 1 0 0 0

1 0 0 * 0 0 0 1

S1 DS1

PLAAND-OR

S2 DS2

S3 DS3

X Y

DFF

DFF

DFF

9.3 FPGA

ECE 545 – Introduction to VHDL

Blo

ck R

AM

s

Blo

ck R

AM

s

ConfigurableLogicBlocks

I/OBlocks

Xilinx FPGA

BlockRAMs

ECE 545 – Introduction to VHDL

CLB CLB

CLB CLB

Logic cell

Slice

Logic cell

Logic cell

Slice

Logic cell

Logic cell

Slice

Logic cell

Logic cell

Slice

Logic cell

Configurable logic block (CLB)

The Design Warrior’s Guide to FPGAsDevices, Tools, and Flows. ISBN 0750676043

Copyright © 2004 Mentor Graphics Corp. (www.mentor.com)

Xilinx CLB

LUT <Look Up Table>

LUT Structure

Interconnection

Logic BlockLogic Block

19

Advantages and Disadvantages

Advantages Short TAT(Turn-Around Time) Small NRE (Non Recurrent Expense) Fee Logic and Timing Design are required. Full amount of IP (Intellectual Property)

Disadvantages Slow speed and Large Chip Area High cost for volume manufacturing

9.4 FPGA Design

FPGA Design

Functional Verification

Logic Synthesis

RTL SimulationRTL

Synthesis Netlist

Gate AssignmentLE Place and Rout

ConfigurationData

FPGA Tool

LSI Tool

FPGA Design Flow

１ bit Adder/Subtracter

4bit Adder/Subtracter

FPGA Design

Three-Step Design Compilation in Quartus II Software

1. Run the New Project Wizard

a. Specify project directory, name, and top-level entity.

b. Specify project design files.c. Specify Altera device family for the design.d. Specify device (or specify device information for

automatic device selection).e. Specify other EDA tools to be used for this project.f. Review project settings.

2. Run the TimeQuest Timing Analyzer

a. On the Process menu, click Start Analysis & Synthesis to build a netlist in preparation for TimeQuest timing analyzer use.b. On the Tools menu, click TimeQuest Timing Analyzer to launch TimeQuest analyzer. i. On the Netlist menu, click Create Timing Netlist and select Post- map to create the timing netlist with timing delay information. ii. Specify your design timing constraints using the analyzer’s graphical user interface (GUI) or by using the Synopsys Design Constraint (SDC) text editor.c. On the Assignment menu, click Timing Analysis Settings to specify TimeQuest analyzer as the timing analysis tool and to add your SDC file to the project.

Quartus II Assignment menu provides all settings and assignments for the project.

3. Compile the Design

a. Select one of the following methods to compile the design: i. On the Processing menu, click Start Compilation. ii. On the menu toolbar, click . iii. On the Processing menu, click Compiler Tool and click Start.b. When compilation is complete, refer to the Compilation Report window to view information on compiler settings, resource usage, and compilation equations.

Timing analysis is also performed during compilation on the current design, and the Compilation Report window includes the timing information.

9.5 Optimization

Trade-offs

speed area

power testability

Speed optimization (1)

better architecture (e.g., CLA vs. ripple carry adder)

pipelining parallel processing optimization options of synthesis

and implementation tools

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Speed optimization (2)

reducing fanout of control signals better state encoding registered outputs from the state

machine