Power Management and Embedded Systems

1
Power Management and Embedded Systems

• Importance of power
• Power Estimation
• Power Management
• Hardware
• Software
• Power Aware Computing, MF Jacome and A
  Ramachandran in Embedded Systems Handbook
• Power Management Techniques for Real-Time
  Embedded Systems, S. Gary. Texas Instruments
  White Paper

2
Why save power?

• Effects of power usage
• Dynamic and Static power
• Power usage

3
Why save power?

• Power usage

4
Power Estimation

• Hardware/Software Co-Design
• Software components, , are the preferred
  solution,
• Custom hardware components are typically used
  only when strictly necessary,
• Power Modeling
• Instruction Level
• Function Level
• Architecture Models

5
Power Management Run-time Solutions

• Goal Design power/energy efficient systems,
  that is, systems that spend energy strictly when
  and where it is needed.
• Gate power and clock(s)
• Adjust frequency and voltage based on work load
  (utilization)
• Modify code

6
Power Management Run-time Solutions

• Gate power and clock(s)
• Turn clocks off
• Power to subsystems only as needed

7
Power Management Run-time Solutions for AtMega
(p. 44)
8
Power Management Run-time Solutions

• Adjust frequency and voltage based on work load
  (utilization)
• Benchmark application to find minimum
  frequency/voltage
• Dynamically adjust frequency/voltage based on
  measured work load
• Dynamically schedule frequency/voltage based on
  predicted work load

9
Power Management Run-time Solutions and AtMega
10
Power Management Run-time Solutions

• Modify code
• Optimize code
• Write better code
• Trade-off some accuracy
• Trade-off some capability

11
Power Management

• Goal Design power/energy efficient systems,
  that is, systems that spend energy strictly when
  and where it is needed.
• Hardware
• Low-power technology base
• Separate voltage and clock domains
• Enable gating of voltages to modules
• Boot with resources unpowered
• Use clock dividers for fast switching of frequency

12
Power Management and Embedded Systems

• Importance of power
• Power Estimation
• Power Management
• Hardware
• Software
• Power Aware Computing, MF Jacome and A
  Ramachandran in Embedded Systems Handbook
• Power Management Techniques for Real-Time
  Embedded Systems, S. Gary. Texas Instruments
  White Paper