Low Power Systems Using Transmeta Crusoe Processors

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Low Power Systems UsingTransmeta Crusoe
Processors

• Bill Gervasi
• Technology Analyst, Transmeta
• Chairman, JEDEC Memory Parametrics
• bilge_at_transmeta.com

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CrusoeÔ 5800 System Architecture
TM5800 CPU
PC133 SDRAM Controller
DDR333 SDRAM Controller
On-Chip Cache
SDR SDRAMPORT
DDR SDRAMPORT
Path Arbiter
Transmeta Crusoe was the first DDR enabled
processor in the industry
PCI Controller
Standard system peripherals
PCI Expansion Bus
Crusoe is a trademark of Transmeta Corp.
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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?
• A 600 MHz CPU
• 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 LongRunÔ PhilosophyUse the least
energypossible to accomplishthe desired task.
LongRun is a trademark of Transmeta Corp.
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Transmeta Crusoe with LongRun

• On Demand processing
• Scale operational frequency onapplication demand
• 33 MHz increments from 400 MHz to CPUs 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 SDR
• 400 MHz CPU ? 200 MHz DDR or 100 MHz SDR

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CPU Without LongRun Technology
Energy required per task
Battery Life
600MHz
800MHz
1GHz

• Users must balance choice of CPU speed against
  decreasing battery life

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CPU With LongRun Technology
Battery Life
Energy required per task
600MHz
800MHz
1GHz

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

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Memory TransitionFrom SDR to DDR
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The JEDEC Memory Roadmap
SDR ? DDR I ? DDR II
3.3V ? 2.5V ? 1.8V

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

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Power DDR II vs DDR I vs SDR
Four times the bandwidth yet half the power!
DDR533 DDR II
DDR333 DDR I
PC133
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Transmetas CPU RoadmapSupports the JEDECMemory
Roadmap.Always has.
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Crusoe Processor Roadmap
TM5500 / TM5800 128-bit VLIW / CMS 4.2 667 MHz -
1 GHz
TM5400 / TM5600 128-bit VLIW / CMS 4.1 500 - 667
MHz
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TM6000 Single Chip PC
DDR-333 64MB-2GB w/ECC
TM6000
4X USB 1.1
Disk Upgrade
AC97 Link
IDE (Flash or Disk)
SMBUS
LVDS
IDE/DVD/CD-RW
24-bit Digital
LPC Bus
PCI Bus
KBC

• 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

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Crusoe TM6000 Microprocessor -- x86 System on a
Chip
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TM6000 System Level Power Management
By integrating the TM6000, LongRun can now be
applied to Graphics and Southbridge electronics
as well.
DVD Play Example TM5800 Solution
CPUNB 1.4
watts Southbridge 0.7 watts Graphics
1.5 watts Total 3.6 watts
3.6 watts
-44
2 watts
TM6000 Solution Total 2.0 watts

TM6000 Solution
TM5800 Solution
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Summary

• Aggressive power management techniques enable new
  mobile and low power computing markets
• Its a systems level design issueapply to all
  subsystems as well

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Thank You