Power Management in Embedded Systems - DAIICT Intranet

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What DPM would not do. ● DPM would not manage the power usage of a device attached. These details are left to the Device Driver. For example, if a system is not currently producing or consuming audio data, the device driver for the audio CODEC interface may power-down the external CODEC chip as well as command the on-board clock and power manager to remove the clock from the CODEC interface peripheral. From the perspective of DPM, since the CODEC is a DMA peripheral these changes alter the bandwidth (frequency) requirements for the on-board peripheral bus, and it might be profitable to also trigger a change in the operating point since the system is no longer constrained by the DMA requirements of the audio subsystem.
Congruence Class ● No device driver has the global view of the system or the power management strategy required to completely specify the operating point. This information is centralized in the DPM policy structure as a congruence class of operating points. ● Any of the operating points in a class would be acceptable as an operating point for the system in the given operating state, although device constraints might render some members of the class invalid, and power considerations might cause one operating point to be preferred over other valid operating points in the class. At any given point in time a valid DPM policy will designate one member of each congruence class as the selected operating point for that class.
Page 1 and 2: Power Management in Embedded System
Page 3 and 4: Importance of Power Management ●
Page 5 and 6: Approaches to Power Management
Page 7 and 8: Static Power Management ● Deals w
Page 9 and 10: Recent Techniques: Hardware Level
Page 11 and 12: Power Dissapation in a CMOS ● Two
Page 13 and 14: Reducing Standby Power Consumption
Page 15 and 16: Relationship between Energy & Frequ
Page 17 and 18: Dynamic Power Management ● Dynami
Page 19 and 20: PC's and embedded devices ● In PC
Page 21 and 22: Policy & Policy Managers ● DPM po
Page 23: Operating State ● If a system sup
Page 27 and 28: Task Example operating points opera
Page 29 and 30: Implementation ● assert_constrain
Page 31: References ● “Dynamic Power Man

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