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+<?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-660A8E4C-F930-415C-8CCC-CB1DCCAA2442" xml:lang="en"><title>Interrupts</title><shortdesc>This document describes how device drivers use interrupts.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-7B450286-637E-4BAB-9D36-9228764CD0D4">      
+      <p>Devices generate interrupts to indicate hardware events. Generally
+drivers provide an interrupt service routine (ISR) to handle the interrupts
+and perform the required responses to the events. Symbian provides an <xref href="GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3.dita"><apiname>Interrupt</apiname></xref> class
+(implemented by the ASSP) with an API to bind and unbind an interrupt source
+and an ISR. </p> <codeblock id="GUID-9EB4BFFE-55A2-56D4-BCF3-6D278C3EC4F4" xml:space="preserve">// Bind the interrupt source ID and interrupt service routine
+TInt Bind(TInt aId, TIsr aIsr, TAny* aPtr);
+// Unbind the interrupt
+TInt Unbind(TInt aId);
+// Enable interrupts on device interrupt source
+TInt Enable(TInt aId);
+// Disable interrupts on device interrupt source
+TInt Disable(TInt aId);
+// Clear the device interrupt
+TInt Clear(TInt aId);
+// Set the priority of the interrupt
+TInt SetPriority(TInt aId, TInt aPriority);</codeblock> <p>Interrupt handling
+is typically done in a PDD, as device hardware access is done at that level.
+Interrupt handling is generally done in two stages in the driver. High priority
+and short time running tasks are done in the ISR, and the remaining processing
+is deferred for handling later. </p> <p>Interrupt handling is a blocking high
+priority task and needs to take a minimal amount of time. The Kernel will
+be in an indeterminate state and puts restrictions on doing various operations. </p> 
+   </section>
+</conbody></concept>
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