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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>