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Symbian3/PDK/Source/GUID-153E6611-D7BC-4B5B-A5C4-38BCA16C1635.dita
author Dominic Pinkman <Dominic.Pinkman@Nokia.com>
Wed, 31 Mar 2010 11:11:55 +0100
changeset 7 51a74ef9ed63
parent 5 f345bda72bc4
permissions -rw-r--r--
Week 12 contribution of API Specs and fix SDK submission

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<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-153E6611-D7BC-4B5B-A5C4-38BCA16C1635" xml:lang="en"><title>Interrupt
Functions</title><shortdesc>Describes the interrupt functions involved in implementing the
Symbian platform GPIO class.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>A common use for a pin is as a hardware interrupt source. The treatment
of interrupts is platform dependent. Typically, the hardware multiplexes all
interrupts from a module into a hardware controller: in this case it is part
of the GPIO implementation to demultiplex the requests. A GPIO implementation
with the capability to demultiplex will also have the capability to enable
and disable interrupts and to bind and unbind their handlers.</p>
<section id="GUID-1ECB1516-C554-4168-AE8C-FA4BDC7BF48F"><title> Implement
the interrupt functions</title> <ul>
<li><p>          Implement <xref href="GUID-6C16DEC3-D0F5-37C0-9EBD-19FE64472F38.dita"><apiname>BindInterrupt()</apiname></xref> with return
value          <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Associate
the specified interrupt service routine with the          specified pin ID.
        </p> </li>
<li><p>          Implement <xref href="GUID-6C16DEC3-D0F5-37C0-9EBD-19FE64472F38.dita"><apiname>BindInterrupt()</apiname></xref> with return
value          <xref href="GUID-0BB03881-8862-35FC-8102-48A2932AB738.dita"><apiname>KErrInUse</apiname></xref>.         </p> <p>          Return <xref href="GUID-0BB03881-8862-35FC-8102-48A2932AB738.dita"><apiname>KErrInUse</apiname></xref> if
an interrupt service          routine is already bound to this interrupt.
        </p> </li>
<li><p>          Implement <xref href="GUID-590E49F1-73A2-3770-80D9-14710982B661.dita"><apiname>UnbindInterrupt()</apiname></xref> with return
         value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Unbind
the specified interrupt service routine with the specified          pin ID.
        </p> </li>
<li><p>          Implement <xref href="GUID-34F2BB96-F39A-34D0-AEF4-543C11BD00FB.dita"><apiname>EnableInterrupt()</apiname></xref> with return
         value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Verify
that the pin is being used as an interrupt source and that          there
is an ISR bound to it. Enable the interrupt.         </p> </li>
<li><p>          Implement <xref href="GUID-E00AE446-FF29-3B97-A38D-5A6B05F51D81.dita"><apiname>DisableInterrupt()</apiname></xref> with return
         value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Verify
that the pin is being used as an interrupt source and that          there
is an ISR bound to it. Disable the interrupt.         </p> </li>
<li><p>          Implement <xref href="GUID-F8C65BDF-21E9-31C1-B124-8791C0A2E766.dita"><apiname>IsInterruptEnabled()</apiname></xref> with return
         value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Verify
that the pin is being used as an interrupt source and that          there
is an ISR bound to it. Determine the status of the interrupt. If it is   
      enabled set <codeph>aEnable</codeph> to True and if it is disabled set
         <xref href="GUID-28B9AB57-B1B6-3D84-A118-FAEA5AD2C23F.dita"><apiname>aEnable</apiname></xref> to False.         </p> </li>
<li><p>          Implement <xref href="GUID-1F8A4B69-BF3D-31C6-934D-93BF47E3E407.dita"><apiname>ClearInterrupt()</apiname></xref> with return
value          <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Clear
the interrupt.         </p> <p>          Only implement this if the hardware
does not automatically clear          the interrupt after reading the interrupt
status.         </p> </li>
<li><p>          Implement <xref href="GUID-3B91EDB8-1BD0-3C13-BF9F-E0A11EC39F84.dita"><apiname>GetMaskedInterruptState()</apiname></xref> with
         return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>      
   Read the interrupt state from the GPIO interrupt controller,          probably
by using a bit mask on a register. Set aActive to True if the          interrupt
state is active and to False if it is inactive.         </p> </li>
<li><p>          Implement <xref href="GUID-F5D98B1C-5397-3E2E-AEBC-E492FA0CBF91.dita"><apiname>GetRawInterruptState()</apiname></xref> with
return          value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>      
   Read the interrupt state directly from the pin. Set          <codeph>aActive</codeph> to
True if the interrupt state is active and to False if          it is inactive.
        </p> <p>          If the hardware does not allow the raw interrupt
state to be          read, implement the function to return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> or
         to return the same value as <xref href="GUID-3B91EDB8-1BD0-3C13-BF9F-E0A11EC39F84.dita"><apiname>GetMaskedInterruptState()</apiname></xref>.
        </p> </li>
<li><p>          Implement these functions with return value          <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>:
        </p> <ul>
<li><p>                <xref href="GUID-6C16DEC3-D0F5-37C0-9EBD-19FE64472F38.dita"><apiname>BindInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-590E49F1-73A2-3770-80D9-14710982B661.dita"><apiname>UnbindInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-34F2BB96-F39A-34D0-AEF4-543C11BD00FB.dita"><apiname>EnableInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-E00AE446-FF29-3B97-A38D-5A6B05F51D81.dita"><apiname>DisableInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-F8C65BDF-21E9-31C1-B124-8791C0A2E766.dita"><apiname>IsInterruptEnabled()</apiname></xref>           
  </p> </li>
</ul> <p>          Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> for these functions
         if the pin does not support interrupts.         </p> </li>
<li><p>          Implement these functions with return value          <xref href="GUID-A94AC24A-EADF-3913-8345-708ED637968E.dita"><apiname>KErrGeneral</apiname></xref>:
        </p> <ul>
<li><p>                <xref href="GUID-590E49F1-73A2-3770-80D9-14710982B661.dita"><apiname>UnbindInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-34F2BB96-F39A-34D0-AEF4-543C11BD00FB.dita"><apiname>EnableInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-E00AE446-FF29-3B97-A38D-5A6B05F51D81.dita"><apiname>DisableInterrupt()</apiname></xref>              </p> </li>
<li><p>                <xref href="GUID-F8C65BDF-21E9-31C1-B124-8791C0A2E766.dita"><apiname>IsInterruptEnabled()</apiname></xref>           
  </p> </li>
</ul> <p>          Return <xref href="GUID-A94AC24A-EADF-3913-8345-708ED637968E.dita"><apiname>KErrGeneral</apiname></xref> for these functions
if          there is no Interrupt Service Routine bound to the pin.      
  </p> </li>
<li><p>          Implement <xref href="GUID-1F8A4B69-BF3D-31C6-934D-93BF47E3E407.dita"><apiname>ClearInterrupt()</apiname></xref> with return
value          <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.         </p> <p>     
    Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if the pin does not       
  support clearing the interrupt signal.         </p> </li>
<li><p>          Implement <xref href="GUID-3B91EDB8-1BD0-3C13-BF9F-E0A11EC39F84.dita"><apiname>GetMaskedInterruptState()</apiname></xref> with
         return value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.         </p> <p> 
        Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if reading the        
 interrupt state is not supported.         </p> </li>
<li><p>          Implement <xref href="GUID-F5D98B1C-5397-3E2E-AEBC-E492FA0CBF91.dita"><apiname>GetRawInterruptState()</apiname></xref> with
return          value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.         </p> <p> 
        Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if reading raw        
 interrupt states is not supported.         </p> </li>
</ul> </section>
</conbody></concept>
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