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<concept id="GUID-9AD35939-26DD-4A42-8727-D0FD2F45B6DE" xml:lang="en"><title>Pin
Mode Functions</title><shortdesc>Describes the pin mode functions involved in implementing the Symbian
platform GPIO class.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>The Symbian platform GPIO class is specified at the level of the pin and
so are the modes. A pin has three modes namely, <keyword>Enabled</keyword>, <keyword>Disabled</keyword> and <keyword>Idle</keyword> as
specified in the enumeration <codeph>TGpioMode</codeph>. The mode of the pin
affects the mode of the module. When a pin is set to Enabled or Disabled mode,
the implementation should set the module to the same mode. When a pin is set
to Idle, the implementation should attempt to set the module to Idle, but
the state and configuration of the other pins on the module may override this.
When a module is set to Idle the implementation should set its pins to Idle
mode.</p>
<section id="GUID-C8665E28-9AA5-4363-9BF1-5AA1ABA5B598"><title>Implement the
pin mode functions</title> <ul>
<li><p>  Implement <xref href="GUID-47A5FEB0-144E-398B-A3B0-8A524A59B7F2.dita"><apiname>SetPinMode()</apiname></xref> for each value of the 
        enumeration <xref href="GUID-BA2AE083-DB8D-327F-85FE-EAB765DAF360.dita"><apiname>TGpioMode</apiname></xref>.  </p> <ul>
<li><p>Implement <xref href="GUID-47A5FEB0-144E-398B-A3B0-8A524A59B7F2.dita"><apiname>SetPinMode()</apiname></xref> with <codeph>aMode</codeph> == <xref href="GUID-500F8E1C-714A-3942-B584-39C44FAF6873.dita"><apiname>EEnabled</apiname></xref> and
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.</p> <p> Enable the pin for GPIO.
Make any functionality other than  GPIO unavailable. Enable the module if
it is not already enabled. This  typically requires power and clocks to be
supplied to the module. </p> </li>
<li><p> Implement <xref href="GUID-47A5FEB0-144E-398B-A3B0-8A524A59B7F2.dita"><apiname>SetPinMode()</apiname></xref> with  <codeph>aMode</codeph> == <xref href="GUID-4EC4F5AE-557D-3249-A3D3-31653DECD706.dita"><apiname>EDisabled</apiname></xref> and
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p> Disable the pin for GPIO.
Disable the module for GPIO. Only a  all to <xref href="GUID-AF952FD7-0B2F-3985-9B1E-02E87734AC6E.dita"><apiname>SetPinMode</apiname></xref> with <xref href="GUID-1D258A78-63B0-3AAF-8359-CB1C62883F38.dita"><apiname>aMode</apiname></xref> ==
 <xref href="GUID-500F8E1C-714A-3942-B584-39C44FAF6873.dita"><apiname>EEnabled</apiname></xref> should return the pin to the enabled state. If
 the pin is enabled for another function, that fact is irrelevant.   </p> </li>
<li><p>                Implement <xref href="GUID-47A5FEB0-144E-398B-A3B0-8A524A59B7F2.dita"><apiname>SetPinMode()</apiname></xref> with    
           <codeph>aMode</codeph> == <xref href="GUID-89A388CF-9DF5-3CD3-AD5E-D2EE98B7F97E.dita"><apiname>EIdle</apiname></xref> and return value
               <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.              </p> <p>        
       Only implement this if the platform supports the idle state.      
       </p> <p>                When the pin is set to the idle state, the
implementation                should also attempt to move the module to the
idle state.              </p> </li>
<li><p>                Implement <xref href="GUID-47A5FEB0-144E-398B-A3B0-8A524A59B7F2.dita"><apiname>SetPinMode()</apiname></xref> with return
value                <xref href="GUID-51298FCE-7857-39F8-BFAB-49AF5556D0CC.dita"><apiname>KErrNotReady</apiname></xref>.              </p> <p> 
              Return <xref href="GUID-51298FCE-7857-39F8-BFAB-49AF5556D0CC.dita"><apiname>KErrNotReady</apiname></xref> when a pin which has
               requested a return to the idle state is not ready to do so.
             </p> </li>
<li><p>                Implement <xref href="GUID-47A5FEB0-144E-398B-A3B0-8A524A59B7F2.dita"><apiname>SetPinMode()</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 is   
            not available for GPIO because it has been assigned an alternative
function and                also where <xref href="GUID-89A388CF-9DF5-3CD3-AD5E-D2EE98B7F97E.dita"><apiname>EIdle</apiname></xref> is passed
and the platform does not                support an idle state.          
   </p> </li>
</ul> </li>
<li><p>          Implement <xref href="GUID-44CFE638-7ECD-369F-8D06-E2970DF078B7.dita"><apiname>GetPinMode()</apiname></xref> for each value
of the          enumeration <xref href="GUID-BA2AE083-DB8D-327F-85FE-EAB765DAF360.dita"><apiname>TGpioMode</apiname></xref>.         </p> </li>
<li><p>             Implement <xref href="GUID-44CFE638-7ECD-369F-8D06-E2970DF078B7.dita"><apiname>GetPinMode()</apiname></xref> with       
     <codeph>aMode</codeph> containing <xref href="GUID-500F8E1C-714A-3942-B584-39C44FAF6873.dita"><apiname>EEnabled</apiname></xref> and return
value             <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.           </p> <p>        
    Verify that the pin is already enabled for GPIO and able to          
  work according to its configuration. Set <xref href="GUID-1D258A78-63B0-3AAF-8359-CB1C62883F38.dita"><apiname>aMode</apiname></xref> to   
         <xref href="GUID-500F8E1C-714A-3942-B584-39C44FAF6873.dita"><apiname>EEnabled</apiname></xref>.           </p> </li>
<li><p>             Implement <xref href="GUID-44CFE638-7ECD-369F-8D06-E2970DF078B7.dita"><apiname>GetPinMode()</apiname></xref> with       
     <codeph>aMode</codeph> containing <xref href="GUID-4EC4F5AE-557D-3249-A3D3-31653DECD706.dita"><apiname>EDisabled</apiname></xref> and return
value             <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.           </p> <p>        
    Verify that the module is already disabled and the pin cannot        
    be used for GPIO. If the pin is enabled for another function, that fact
is             irrelevant.           </p> </li>
<li><p>             Implement <xref href="GUID-44CFE638-7ECD-369F-8D06-E2970DF078B7.dita"><apiname>GetPinMode()</apiname></xref> with       
     <codeph>aMode</codeph> containing <xref href="GUID-89A388CF-9DF5-3CD3-AD5E-D2EE98B7F97E.dita"><apiname>EIdle</apiname></xref> and return
value             <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.           </p> <p>        
    Only implement this if the platform supports the idle state.         
 </p> <p>             Verify that the module is already in an idle state.
          </p> </li>
<li><p>             Implement <xref href="GUID-44CFE638-7ECD-369F-8D06-E2970DF078B7.dita"><apiname>GetPinMode()</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 platform    
        does not support reading the pin mode.           </p> </li>
</ul></section>
</conbody></concept>