1 <?xml version="1.0" encoding="utf-8"?>

     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

     3 <!-- This component and the accompanying materials are made available under the terms of the License 

     4 "Eclipse Public License v1.0" which accompanies this distribution, 

     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

     6 <!-- Initial Contributors:

     7     Nokia Corporation - initial contribution.

     8 Contributors: 

     9 -->

    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-90E2A645-56B0-4FC2-AE92-CD72FEC23AE6" xml:lang="en"><title>Input

    13 and Output Functions</title><shortdesc>Describes the input and output functions involved in implementing

    14 the Symbian platform GPIO class.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    15 <p>There is no general reason why a pin which is available for use for GPIO

    16 should not also be available for some other function, and the Symbian platform

    17 GPIO specification allows for this. There are certain circumstances where

    18 pin sharing should be prevented, for instance when a pin is in use as an interrupt

    19 source, and these cases are specified individually.  </p>

    20 <section id="GUID-84ACB7AB-F6DE-42F5-8C89-C7598FBC7AC1"><title>Implement the

    21 Input/output functions</title> <ul>

    22 <li><p>          Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> for each value

    23 of          <xref href="GUID-7C1D78B4-9897-3C38-8EE7-7C311B885B0B.dita"><apiname>TGpioState</apiname></xref>.         </p> <ul>

    24 <li><p>                Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with

    25                <codeph>aState</codeph> == <xref href="GUID-ABF52F3A-CDC3-3AC6-89ED-FB7F5B781A25.dita"><apiname>ELow</apiname></xref> and return

    26 value                <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.              </p> <p>  

    27              Verify that the pin is being used as a binary output. Set it

    28                to its low electric state.              </p> </li>

    29 <li><p>                Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with

    30                <codeph>aState</codeph> == <xref href="GUID-28B7F356-760B-38EA-90B1-AD3594375CBC.dita"><apiname>EHigh</apiname></xref> and return

    31 value                <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.              </p> <p>  

    32              Verify that the pin is being used as a binary output. Set it

    33                to its high electric state.              </p> </li>

    34 <li><p>                Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with

    35                <codeph>aState</codeph> == <xref href="GUID-A538A8AF-DA50-3641-A794-19CAFF5B28F2.dita"><apiname>EDefaultIdleState</apiname></xref> and

    36 return value                <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.              </p> <p> 

    37               Verify that the pin is being used as a binary output. Set its

    38                electric state to its default idle state.              </p> </li>

    39 <li><p>                Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with

    40 return                value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.         

    41     </p> <p>                If the specified electric state is not supported

    42 return                <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.              </p> </li>

    43 </ul> </li>

    44 <li><p>          Implement <xref href="GUID-E88C05CA-8882-3C6A-9B64-8048DB7DA622.dita"><apiname>GetOutputState()</apiname></xref> with return

    45 value          <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Verify

    46 that the pin is being used as a binary output. Determine          its electric

    47 state and set <codeph>aState</codeph> to the appropriate value of        

    48  <xref href="GUID-7C1D78B4-9897-3C38-8EE7-7C311B885B0B.dita"><apiname>TGpioState</apiname></xref>.         </p> </li>

    49 <li><p>          Implement <xref href="GUID-9BFB4B87-1400-33C0-B116-AC6FA349BE1E.dita"><apiname>GetInputState()</apiname></xref> with return

    50 value          <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>.         </p> <p>          Verify

    51 that the pin is being used as a binary input. Determine          its electric

    52 state and set <codeph>aState</codeph> to the appropriate value of        

    53  <xref href="GUID-7C1D78B4-9897-3C38-8EE7-7C311B885B0B.dita"><apiname>TGpioState</apiname></xref>.         </p> </li>

    54 </ul></section>

    55 </conbody></concept>