61 lines
2.5 KiB
HTML
61 lines
2.5 KiB
HTML
<html devsite>
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<head>
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<title>Interaction</title>
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<meta name="project_path" value="/_project.yaml" />
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<meta name="book_path" value="/_book.yaml" />
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</head>
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<body>
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<!--
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Copyright 2017 The Android Open Source Project
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<p>From the perspective of Android applications, every Android sensor is an
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independent entity, meaning there is no interaction between the different
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sensors.</p>
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<ul>
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<li> This is true even though several Android sensors might share the same
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underlying physical sensor </li>
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<li> For example: step counter, significant motion and accelerometer, all relying on
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the same physical accelerometer, must be able to work concurrently </li>
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<li> This is also true for wake-up and non-wake-up versions of the same sensor </li>
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</ul>
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<p>Android sensors must be able to work simultaneously and independently of one
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another. That is, any action on one Android sensor must not impact the behavior
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of the other sensors.</p>
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<p>Specifically, at the HAL level:</p>
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<ul>
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<li> activating a sensor </li>
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<li> deactivating a sensor </li>
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<li> changing the sampling frequency of a sensor </li>
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<li> changing the maximum reporting latency of a sensor </li>
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</ul>
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<p>cannot cause:</p>
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<ul>
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<li> another activated sensor to stop working </li>
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<li> another activated sensor to change sampling rate </li>
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<li> another activated sensor to decrease the quality of its measurements </li>
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<li> another non-activated sensor to start delivering events </li>
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</ul>
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<p>Nor can any of the actions above prevent actions (activation, deactivation,
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and parameter changes) on another sensor from succeeding. For instance,
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whether we can activate the step counter must be independent of whether the
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accelerometer is currently activated. </p>
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<p>As another important example, a wake-up sensor activated at 5Hz must generate events
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at around 5Hz, even if its non-wake-up variant is being activated at 100Hz.</p>
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</body>
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</html>
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