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authorClay Murphy <claym@google.com>2014-06-11 21:38:32 +0000
committerAndroid Git Automerger <android-git-automerger@android.com>2014-06-11 21:38:32 +0000
commite751014022d7e9095fd15e2d18787d5f9caa0e3a (patch)
tree4ff3621f53305cc2d8d15ef8eaa4239254f62a4d
parent1f4d2c456926898e6b376a99fe150c15d22b1fa7 (diff)
parenta1e248f68a8cc442a44c133de8bc6a73756a878f (diff)
downloadsource.android.com-e751014022d7e9095fd15e2d18787d5f9caa0e3a.tar.gz
am a1e248f6: am 622ff910: am 7875f63e: Merge "Docs: Adding example of period_ns to on-change entry."
* commit 'a1e248f68a8cc442a44c133de8bc6a73756a878f': Docs: Adding example of period_ns to on-change entry.
-rw-r--r--src/devices/sensors/base_triggers.jd21
1 files changed, 15 insertions, 6 deletions
diff --git a/src/devices/sensors/base_triggers.jd b/src/devices/sensors/base_triggers.jd
index 1d2bd78a..81d25477 100644
--- a/src/devices/sensors/base_triggers.jd
+++ b/src/devices/sensors/base_triggers.jd
@@ -28,16 +28,25 @@ page.title=Base sensors and trigger modes
<p>Sensors can report events in different ways called trigger modes; each sensor
type has one and only one trigger mode associated to it. Four trigger modes
exist:</p>
+
<h3 id="continuous">Continuous</h3>
<p>Events are reported at a constant rate defined by setDelay(). Example sensors
using the continuous trigger mode are accelerometers and gyroscopes.</p>
+
<h3 id="on-change">On-change</h3>
-<p>Events are reported only if the sensor's value has changed. setDelay() is used
- to set a lower limit to the reporting period, meaning the minimum time between
- consecutive events. Activating the sensor also triggers an event. The HAL must
- return an event immediately when an on-change sensor is activated. Example
- sensors using the on-change trigger mode are the step counter and proximity
- sensor types.</p>
+<p>Events are reported only if the sensor's value has changed. Activating the
+sensor also triggers an event, meaning the HAL must return an event immediately
+when an on-change sensor is activated. Example sensors using the on-change
+trigger mode are the step counter and proximity sensor types.</p>
+
+<p>Here is how the <code>period_ns</code> parameter affects setDelay(...) and
+batch(...). The <code>period_ns</code> parameter is used to set a lower limit
+to the reporting period, meaning the minimum time between consecutive events.
+Here is an example: If activating the step counter with period_ns = 10 seconds,
+walking for 1 minute, and then not walking for 1 minute, the events will
+be generated every 10 seconds during the first minute, and no event will be
+generated in the second minute.</p>
+
<h3 id="one-shot">One-shot</h3>
<p>Upon detection of an event, the sensor deactivates itself and then sends a
single event. Order matters to avoid race conditions. No other event is sent