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<concept id="GUID-113B3755-1797-5D1B-8E07-8A18F5FE1504" xml:lang="en"><title>Power States</title><shortdesc>Describes three power states that are defined by the kernel.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<ul>

<li id="GUID-61A3C566-05AA-5F6D-A9DE-B409C873B119"><p> <i>Off</i> -

a state where the device and all peripherals are powered off or inactive,

or are characterised by negligible power consumption due to current

leakage to the electric and electronic circuits that make up the system.

This state is achieved as a result of controlled system shutdown resulting

from a user action, an application request, UI inactivity, or as a

result of accidental loss of power. This may also be achieved as a

result of putting the system into a hibernation state. Note that a

reboot is necessary to return the system to the <i>Active</i> state;

this could be a cold reboot, or a warm reboot if the system was put

into a hibernation state. </p> </li>

<li id="GUID-275417B2-B8C8-5C93-B576-15543D80CAC9"><p> <i>Standby</i> - a low power consuming state that results from turning off most

system resources (clocks, voltages), peripherals, memory banks (where

possible), cpu and internal logic, while still retaining the state

prior to the transition. Typically, the only systems that are active

are those that are required to detect the events that force the transition

back to the Active state (e.g. RTC, clocks and Peripherals involved

in detecting hardware events). Returning to the Active state will

normally take a far shorter period of time than that required to reboot

the system. This state is achieved as a result of user action or application

request. </p> </li>

<li id="GUID-A31A5A3C-C7C2-5D15-88B2-828F7E5F60D8"><p> <i>Active</i> - the fully active state. </p> </li>

</ul>

<p>The three power states are defined by the enum values of the <xref href="GUID-87AB8B20-04EE-31D2-8F3D-EA904D05B8D0.dita"><apiname>TPowerState</apiname></xref> enum defined in <filepath>e32power.h</filepath>. </p>

</conbody><related-links>

<link href="GUID-E09E4418-4DC3-56A3-BFBE-486C9C8D25C9.dita"><linktext>Domain

Manager</linktext></link>

<link href="GUID-0C435514-EEC6-5660-BB5F-535790349632.dita"><linktext>Power

Management</linktext></link>