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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-74FE6572-14B9-4B94-8DD0-803DA21D14A3" xml:lang="en"><title>Wakeup |
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13 Functions</title><shortdesc>Describes the wakeup functions involved in implementing the Symbian |
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14 platform GPIO class.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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15 <p>One important use of GPIO input pins is to signal a wakeup request to the |
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16 CPU. Wakeup requests will usually take place when the system is idling and |
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17 clocks are switched off. This means that the kind of trigger used to signal |
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18 wakeups must be detected asynchronously (not on a clock edge) and hence that |
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19 a wakeup trigger should probably be configured for edge detection and not |
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20 level detection. Since a wakeup is generic to the whole CPU regardless of |
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21 its origin, wakeups are usually combined into a single signal by a logical |
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22 OR operation. </p> |
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23 <section id="GUID-19811A8B-5A8F-4769-8686-1BB49C56532F"><title>Implement the |
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24 wakeup functions</title> <ul> |
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25 <li><p> Implement <xref href="GUID-1C41DDCD-7BE3-3BDA-A832-C2C9821AEB09.dita"><apiname>EnableWakeup()</apiname></xref> with return |
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26 value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p> |
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27 Enable wakeup on the pin. </p> </li> |
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28 <li><p> Implement <xref href="GUID-21432D3C-90DA-35AA-AFB5-C7FF37ED0806.dita"><apiname>DisableWakeup()</apiname></xref> with return |
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29 value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p> |
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30 Disable wakeup on the pin. </p> </li> |
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31 <li><p> Implement <xref href="GUID-D58B6C13-F3B0-3E18-A7ED-DE177BC2CCEB.dita"><apiname>IsWakeupEnabled()</apiname></xref> with |
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32 return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p> |
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33 Verify that the pin supports wakeup and determine the wakeup |
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34 state. If is enabled set <xref href="GUID-28B9AB57-B1B6-3D84-A118-FAEA5AD2C23F.dita"><apiname>aEnable</apiname></xref> to True |
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35 and if it is disabled set <xref href="GUID-28B9AB57-B1B6-3D84-A118-FAEA5AD2C23F.dita"><apiname>aEnable</apiname></xref> to False. |
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36 </p> </li> |
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37 <li><p> Implement these functions with return value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>: |
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38 </p> <ul> |
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39 <li><p> <xref href="GUID-1C41DDCD-7BE3-3BDA-A832-C2C9821AEB09.dita"><apiname>EnableWakeup()</apiname></xref> </p> </li> |
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40 <li><p> <xref href="GUID-21432D3C-90DA-35AA-AFB5-C7FF37ED0806.dita"><apiname>DisableWakeup()</apiname></xref> </p> </li> |
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41 <li><p> <xref href="GUID-D58B6C13-F3B0-3E18-A7ED-DE177BC2CCEB.dita"><apiname>IsWakeupEnabled()</apiname></xref> </p> </li> |
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42 </ul> <p> Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if the pin does |
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43 not support wakeups. </p> </li> |
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44 </ul> </section> |
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45 </conbody></concept> |