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<concept id="GUID-583F70B4-5C8C-54FA-A869-E6F073DE1FD6" xml:lang="en"><title>Interrupt::Enable()

and Interrupt::Disable()</title><shortdesc>The functions <codeph>Interrupt::Enable()</codeph> and <codeph>Interrupt::Disable()</codeph> are

used by device drivers to enable and disable the interrupt source in the interrupt

controller hardware. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p/>

<p>An <xref href="GUID-76A30EC4-4B99-5471-9E80-F853C91485BC.dita#GUID-76A30EC4-4B99-5471-9E80-F853C91485BC/GUID-8E58F4C9-0290-55E0-A4FD-B6C2361BE205">Interrupt

ID</xref> is passed to the functions to identify the interrupt source. All

requests for enabling and disabling interrupts should go to these functions

in the <xref href="GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3.dita"><apiname>Interrupt</apiname></xref> class so that device drivers should never

need to know where the interrupt is actually implemented. The general rule

is that the interrupt ID is tagged in some way to allow these functions to

decide whether the interrupt refers to the ASSP layer or to the Variant layer.

These functions are implemented in the ASSP layer. </p>

<p>The implementation of these functions is completely dependent on the interrupt

hardware. In the template port, <codeph>Interrupt::Enable()</codeph> is implemented

in <filepath>...\template_assp\interrupts.cpp</filepath>. The relevant part

is: </p>

<codeblock id="GUID-8A99386B-5681-5ABA-B4BB-735DF2C2695A" xml:space="preserve">EXPORT_C TInt Interrupt::Enable(TInt anId)

    {

     __KTRACE_OPT(KEXTENSION,Kern::Printf("Interrupt::Enable id=%d",anId));

     TInt r=KErrNone;

     // if ID indicates a chained interrupt, call variant...

     if (anId<0 && ((((TUint)anId)>>16)&0x7fff)<(TUint)KNumTemplateInts)

         r=TemplateAssp::Variant->InterruptEnable(anId);

     else if ((TUint)anId>=(TUint)KNumTemplateInts)

         r=KErrArgument;

     else if (TemplateInterrupt::Handlers[anId].iIsr==TemplateInterrupt::Spurious)

         r=KErrNotReady;

     else

         {

         //

         // TO DO: (mandatory)

         //

         // Enable the corresponding Hardware Interrupt source

         //

         }

     return r;

    }

          </codeblock>

<p>Interrupts that 'belong' to the Variant Layer are passed to that layer

through the call to: </p>

<codeblock id="GUID-05C36364-3912-5EEE-B851-82803A731950" xml:space="preserve">r =TemplateAssp::Variant-&gt;InterruptEnable(anId);</codeblock>

<p> <codeph>Interrupt::Disable()</codeph> follows the same general pattern. </p>

<p>The Variant layer equivalent of this function, <codeph>Template::InterruptEnable()</codeph>,

in <filepath>...\template_variant\specific\variant.cpp</filepath>, also follows

the same pattern. </p>

</conbody></concept>