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<!DOCTYPE concept
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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>
</related-links></concept>