Low Power Systems Using

Transmeta Crusoe Processors

Bill Gervasi

Technology Analyst, Transmeta

Chairman, JEDEC Memory Parametrics

bilge@transmeta.com

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Crusoe 5800 System Architecture

TM5800

CPUP

C1

33

SD

RA

M C

on

tro

ller

DD

R33

3 S

DR

AM

Co

ntr

olle

r

PCI Controller

On-Chip Cache

Path Arbiter

DDR SDRAMPORT

SDR SDRAMPORT

PCI Expansion Bus

Standard system peripherals

Crusoe is a trademark of Transmeta Corp.

Transmeta Crusoe was the first DDR enabled processor

in the industry

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Advantages of Integrated Memory Control

One less bus to waste power

Low latency to memory after cache miss

No synchronization penalties– Unique source synchronous & true

synchronous memory design– Memory clock domain tied to CPU clock

domain

Aggressive power management coordinated with CPU power states

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A Brief Tutorial on Power Consumption

Power = CV2f%

Factors:

Capacitance (C)

Voltage (V)

Frequency (f)

Duty cycle (%)

Power states

Keys tolow power design:

Reduce C and V Match f to demand Minimize duty cycle Utilize power states

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Quiz #1 on CPU Power

Question:

Which Burns More Energy?

1. A 600 MHz CPU2. A 1 GHz CPU

Hint: This is a trick question.

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Answer to Quiz #1

Assume the 600 MHz CPU is a downbin of the 1 GHz CPU

If the task load, such as DVD decode, requires 600 MHz of processing power– The 600 MHz CPU must be maxed out with its

highest core voltage, e.g., 1.2V– The 1 GHz CPU can be throttled to 600 MHz

and can have its core voltage reduced, e.g., 1V

Conclusion: The 1 GHz CPU burns less energy for a given task than the 600 MHz CPU

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The LongRun Philosophy

Use the least energypossible to accomplish

the desired task.

LongRun is a trademark of Transmeta Corp.

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Transmeta Crusoe with LongRun

On Demand processingScale operational frequency onapplication demand– 33 MHz increments from 400 MHz to CPU’s

max frequency– Adjust core voltage to minimum for the desired

target frequency– LongRun events hundreds of times per second

Memory clock speed relative to CPU speed, e.g.:1 GHz CPU 333 MHz DDR or 167 MHz SDR400 MHz CPU 200 MHz DDR or 100 MHz SDR

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CPU Without LongRun Technology

Users must balance choice of CPU speed against decreasing battery life

600MHz

800MHz

1GHz

Battery Life

Energy required per task

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CPU With LongRun Technology

Users will want the highest MHz CPU– Best Performance– Lower Power– Longest battery life

600MHz

800MHz

1GHz

Battery Life

Energy required per task

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Memory Transition

From SDR to DDR

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The JEDEC Memory Roadmap

JEDEC roadmap triples GB/s/W with each generation– Power reduction of 30%– Bandwidth doubles

SDR DDR I DDR IISDR DDR I DDR II3.3V 2.5V 1.8V3.3V 2.5V 1.8V

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Power: DDR II vs DDR I vs SDR

Relative GB/s per Watt

PC133

DDR333

“DDR I”

Four times the bandwidth yet half the power!

DDR533

“DDR II”

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Transmeta’s CPU RoadmapSupports the JEDECMemory Roadmap.

Always has.

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TM6000x86 System On a Chip128-bit VLIW / CMS 5.x

1 GHzLess Power and Space

Crusoe Processor Roadmap

Crusoe Processor Roadmap

TM5400 / TM5600128-bit VLIW / CMS 4.1

500 - 667 MHz

TM5500 / TM5800128-bit VLIW / CMS 4.2

667 MHz - 1 GHz

Next Generation Crusoe256-bit VLIW / New CMS

2-3x Performance

2000 2001 2002

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TM6000 Single Chip PC

TM6000 Single Chip PC is Ideal for Wireless Internet Devices

Smallest Footprint

Lowest Power

Highest Performance (400 MHz to 1 GHz)

Full x86 Compatibility

Optional Support for External 3D Graphics

PCI Bus

4X USB 1.1

LPC Bus

IDE/DVD/CD-RW

TM6000

AC97 Link

KBC

SMBUS

LVDS24-bit Digital

DDR-33364MB-2GB w/ECC

IDE (Flash or Disk)

Disk Upgrade

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DDR333 Memory Controller• 2.7 GB/s DDR with ECC

Crusoe TM6000 Microprocessor -- x86 System on a Chip

Universal Serial Bus (USB)• 4 Ports OHCI 1.0a

AC-Link Audio/Modem

System Management bus

Low Pin Count bus (LPC)

8 General Purpose I/Os

Legacy PC Peripherals• Dual 8259 Int. Controller• Dual 8237 DMA Controller• 8254 System Timer• 146818 Real Time Clock• 16550 UART

Graphics Controller• 24 bit digital and • LVDS interfaces• Dual Scan LCD and CRT• DVD playback support

PCI Bus Interface

IDE Disk Controller• 2 Channel / 4 DrivesCentral Processor Unit

• 1 GHz • 0.9 - 1.3 volt LongRun• 128-bit VLIW Engine• 512KB L2 Cache

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TM

5800

S

olu

tion

3.6 wattsDVD Play Example:TM5800 Solution CPU+NB = ~1.4 wattsSouthbridge = ~0.7 wattsGraphics = ~1.5 wattsTotal = ~3.6 watts

TM6000 System Level Power Management By integrating the TM6000, LongRun can now be applied to Graphics and Southbridge electronics as well.

TM

6000

S

olu

tion

~2 watts

TM6000 SolutionTotal = ~2.0 watts

-44%

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Summary

Aggressive power management techniques enable new mobile and low power computing markets

It’s a systems level design issue…apply to all subsystems as well

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Thank You