ZEUS Technical Manual

Power and power management

 

 

Processor power management

First available in the PXA270 processor, Wireless Intel SpeedStep Technology dynamically adjusts the power and performance of the processor based on CPU demand. This can result in a significant decrease in power consumption.

In addition to the capabilities of Intel Dynamic Voltage Management, the Intel XScale micro architecture of the PXA27x family incorporates three new low power states. These are deep idle, standby and deep sleep. It is possible to change both voltage and frequency on the fly by intelligently switching the processor into the various low power modes. This saves additional power while still providing the necessary performance to run rich applications.

Wireless Intel SpeedStep technology includes the following features:

•Five reset sources: power-on, hardware, watchdog, GPIO and exit from sleep and deep-sleep modes (sleep-exit).

•Multiple clock-speed controls to adjust frequency, including frequency change, turbo mode, half-turbo mode, fast-bus mode, memory clock, 13M mode, A-bit mode and AC ’97.

•Switchable clock source.

•Functional-unit clock gating.

•Programmable frequency-change capability.

•One normal-operation power mode (run mode) and five low power modes to control power consumption (idle, deep-idle, standby, sleep and deep-sleep modes).

•Programmable I2C-based external regulator interface to support changing dynamic core voltage, frequency change and power mode coupling.

The PXA270 power consumption depends on the operating voltage and frequency, peripherals enabled, external switching activity, external loading and other factors. The tables below contain power consumption information at room temperature for several operating modes: active, idle and low power. For active power consumption data, no PXA270 peripherals are enabled except for on-chip UARTs.

© 2007 Eurotech Ltd Issue D

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