--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adaptation/GUID-C661B40F-1439-587F-9E8E-DB2DFC79C040.dita	Fri Oct 15 14:32:18 2010 +0100
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-C661B40F-1439-587F-9E8E-DB2DFC79C040" xml:lang="en"><title>HAL Groups</title><shortdesc>Description of HAL groups to add new attributes.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>You can extend <xref href="GUID-9AE254D4-AA60-579E-8D9D-F2797106A413.dita#GUID-9AE254D4-AA60-579E-8D9D-F2797106A413/GUID-366CC4B8-C6BD-5DCC-B55D-6D87CD5C8E64">HAL groups</xref> to add new attributes and new types of hardware. </p>
+<section id="GUID-7ACAB5F0-08A8-4D53-9F47-9E77642F7337"><title>Extending
+an existing hardware type</title> <p>Each HAL group has an associated
+set of function numbers. For example, the enumerators of <codeph>TDisplayHalFunction</codeph>, in <filepath>u32std.h</filepath> define the functions associated
+with the HAL group <codeph>EHalGroupDisplay</codeph>. </p> <p>In this
+specific case, new state can be represented by a new function number,
+and by changing the <xref href="GUID-124AC7EE-E227-5358-A755-628FFE257250.dita">HAL handler implementation</xref> to deal with the new function number. </p> <p>It is
+important to note that any new function numbers should not follow
+consecutively from those defined by Symbian. Instead, choose high
+values so that they are guaranteed not to clash with any future Symbian
+extensions. Symbian will always use new values that follow consecutively
+from previous Symbian defined values. </p> </section>
+<section id="GUID-A819D9EA-A16F-4806-B8E8-C7ED008C6D31"><title>New
+hardware type</title> <p>Although up to 32 HAL groups can be defined,
+Symbian platform does not use all 32. This leaves some values that
+can be used for new hardware. </p> <p>In this case choose a HAL group
+number at the high end of the range, so that it is guaranteed not
+to clash with any future Symbian extensions. Symbian will always use
+new values that follow consecutively from previous Symbian defined
+values. </p> </section>
+</conbody></concept>
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