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<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<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>