Week 12 contribution of SDK documentation_content. See release notes for details. Fixes Bug 1892, Bug 1522, Bug 1520, Bug 394, Bug 1319, Bug 344, Bug 1897
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
<!-- This component and the accompanying materials are made available under the terms of the License
"Eclipse Public License v1.0" which accompanies this distribution,
and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
<!-- Initial Contributors:
Nokia Corporation - initial contribution.
Contributors:
-->
<!DOCTYPE concept
PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-48AEF60B-D2B6-55B5-96FD-55C1F1868A3F" xml:lang="en"><title>GPIO
Implementation Guide</title><shortdesc>This document tells you things you need to know to produce a platform
specific implementation of the Symbian platform generic GPIO interface. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<section id="GUID-DF9D655C-161E-5EC0-815C-4AD3483ED290"><title>Required background</title> <p>Before
you start, you must: </p> <ul>
<li id="GUID-210FC785-9589-5E8B-9A10-115359521C3D"><p>understand platform
implementation, </p> </li>
<li id="GUID-9DFA66B1-316A-5D23-8DEB-CC82EFA4E1A9"><p>understand GPIO concepts
and terminology, </p> </li>
<li id="GUID-5B26CDEE-B6F4-5A19-A675-7614159F7786"><p>know the architecture
of the platform on which you are implementing, and </p> </li>
<li id="GUID-680844F2-25CC-5E95-B1E0-943D5E119555"><p>understand the C++ signature
of the functions you are implementing. </p> </li>
</ul> </section>
<section id="GUID-3657983A-8801-4F51-B996-70D942DBD17B"><title>Introduction</title> <p>You can provide support for GPIO hardware
in a board support package by implementing the interface that Symbian platform
defines in the GPIO class. To provide a consistent interface to clients of
the GPIO class, your implementation must return certain error codes in certain
specified conditions. The details of the functions, conditions and associated
required return values are described below. How your implementation of the
functions communicates with your GPIO hardware will be specific to the hardware
you are using. </p> </section>
<section id="GUID-37F49486-8821-4CED-BC19-5818D890CD85"><title>Procedure</title><p>Implement each function of class <xref href="GUID-C93C53D3-2BE8-36AE-83B8-4CDB4195649B.dita"><apiname>GPIO</apiname></xref> with
a return value of </p> <ul id="GUID-B39F7C57-765D-54AF-8296-4A9C6EF8D75E">
<li id="GUID-9E22A75B-E0E0-54D8-B4BB-DCF0E52C8DAD"><p> <xref href="GUID-C93C53D3-2BE8-36AE-83B8-4CDB4195649B.dita"><apiname>KErrArgument</apiname></xref>, </p> </li>
<li id="GUID-735EE673-F24B-5ACC-AF9D-DD3437D763D9"><p> <xref href="GUID-C93C53D3-2BE8-36AE-83B8-4CDB4195649B.dita"><apiname>KErrNone</apiname></xref>, </p> </li>
<li id="GUID-EA824100-5317-599D-9270-A93EDF1A6275"><p> <xref href="GUID-C93C53D3-2BE8-36AE-83B8-4CDB4195649B.dita"><apiname>KErrNotSupported</apiname></xref> </p> </li>
</ul><p>and other return values as specified for particular functions.</p></section>
<section id="GUID-3D5B6289-7C6D-48BC-9A56-500DD10CD64C"><title>Returning KErrArgument</title> <p> Implement each function
of class <xref href="GUID-C93C53D3-2BE8-36AE-83B8-4CDB4195649B.dita"><apiname>GPIO</apiname></xref> with a return value of <xref href="GUID-0BEA3647-7888-3612-A2D3-7E27AC405E29.dita"><apiname>KErrArgument</apiname></xref>.
</p> <p> The first argument of every function is <codeph>aId</codeph> and
represents the ID of a pin. If the passed-in ID is invalid, the function should
return <xref href="GUID-0BEA3647-7888-3612-A2D3-7E27AC405E29.dita"><apiname>KErrArgument</apiname></xref> without further activity. </p> </section>
<section id="GUID-C8665E28-9AA5-4363-9BF1-5AA1ABA5B598"><title>Pin mode functions</title> <p>Implement the pin mode functions.
</p> <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>
<section id="GUID-3DA1E4AC-BAE0-469E-8A5D-72E292A533C1"><title>Pin direction functions</title><p>Implement the pin direction
functions.</p> <ul>
<li><p> Implement <xref href="GUID-38FAAC57-13CF-390F-AE05-8D2B9E092450.dita"><apiname>SetPinDirection()</apiname></xref> for each value
of the enumeration <xref href="GUID-2F6DB4C0-D198-39A8-B990-EF1D5B9B5901.dita"><apiname>TGpioDirection</apiname></xref>.</p><ul>
<li><p> Implement <xref href="GUID-38FAAC57-13CF-390F-AE05-8D2B9E092450.dita"><apiname>SetPinDirection()</apiname></xref> with
<codeph>aDirection</codeph> == <xref href="GUID-EC5870C2-5C3E-3DFB-9349-85AAF1A0AE58.dita"><apiname>EInput</apiname></xref> and return
value <codeph>KErrNone.</codeph> </p> <p>
Set the pin to behave as an input binary signal. </p> </li>
<li><p> Implement <xref href="GUID-38FAAC57-13CF-390F-AE05-8D2B9E092450.dita"><apiname>SetPinDirection()</apiname></xref> with
<codeph>aDirection</codeph> == <xref href="GUID-8E81439B-6FB5-3EEC-BC36-F3B70217FA8D.dita"><apiname>EOutput</apiname></xref> and return
value <codeph>KErrNone.</codeph> </p> <p>
Set the pin to behave as an output binary signal. </p> </li>
<li><p> Implement <xref href="GUID-38FAAC57-13CF-390F-AE05-8D2B9E092450.dita"><apiname>SetPinDirection()</apiname></xref> with
<codeph>aDirection</codeph> == <xref href="GUID-2AEEC0C1-CF80-3C1D-B24B-17178ACA6AB4.dita"><apiname>ETriStated</apiname></xref> and
return value <codeph>KErrNone.</codeph> </p> <p>
Set the pin to be in a quiescent state (also called floating or
deactivated). </p> <p> Only implement this
if the platform supports the quiescent state. The physical state
of the pin will be determined by the drive on the line.
</p> </li>
<li><p> Implement <xref href="GUID-38FAAC57-13CF-390F-AE05-8D2B9E092450.dita"><apiname>SetPinDirection()</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 cannot
operate in the direction specified, for instance if <xref href="GUID-2AEEC0C1-CF80-3C1D-B24B-17178ACA6AB4.dita"><apiname>ETriStated</apiname></xref> has
been passed and the platform does not support the quiescent state.
</p> </li>
</ul></li>
<li><p> Implement <xref href="GUID-062A11F7-123D-334C-A082-F21DB9A9EE32.dita"><apiname>GetPinDirection()</apiname></xref> for each value
of the enumeration <xref href="GUID-2F6DB4C0-D198-39A8-B990-EF1D5B9B5901.dita"><apiname>TGpioDirection</apiname></xref>. </p> <ul>
<li><p> Implement <xref href="GUID-062A11F7-123D-334C-A082-F21DB9A9EE32.dita"><apiname>GetPinDirection()</apiname></xref> with
<codeph>aDirection</codeph> containing <xref href="GUID-EC5870C2-5C3E-3DFB-9349-85AAF1A0AE58.dita"><apiname>EInput</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 behaving as a binary input signal. Set
<xref href="GUID-221FF753-F089-399C-BD67-A693E68AB727.dita"><apiname>aDirection</apiname></xref> to <xref href="GUID-EC5870C2-5C3E-3DFB-9349-85AAF1A0AE58.dita"><apiname>EInput</apiname></xref>
</p> </li>
<li><p> Implement <xref href="GUID-062A11F7-123D-334C-A082-F21DB9A9EE32.dita"><apiname>GetPinDirection()</apiname></xref> with
<codeph>aDirection</codeph> containing <xref href="GUID-8E81439B-6FB5-3EEC-BC36-F3B70217FA8D.dita"><apiname>EOutput</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 behaving as a binary output signal. Set
<codeph>aDirection</codeph> to <xref href="GUID-EC5870C2-5C3E-3DFB-9349-85AAF1A0AE58.dita"><apiname>EInput</apiname></xref>
</p> </li>
<li><p> Implement <xref href="GUID-062A11F7-123D-334C-A082-F21DB9A9EE32.dita"><apiname>GetPinDirection()</apiname></xref> with
<codeph>aDirection</codeph> containing <xref href="GUID-2AEEC0C1-CF80-3C1D-B24B-17178ACA6AB4.dita"><apiname>ETriStated</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 in the quiescent state. Set <codeph>aDirection</codeph> to <xref href="GUID-2AEEC0C1-CF80-3C1D-B24B-17178ACA6AB4.dita"><apiname>ETriStated</apiname></xref>
</p> </li>
<li><p> Implement <xref href="GUID-062A11F7-123D-334C-A082-F21DB9A9EE32.dita"><apiname>GetPinDirection()</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 pin
direction is not supported. </p> </li>
</ul></li>
</ul> </section>
<section id="GUID-35D80FC2-4DBF-4FF2-ACB4-409020651F86"><title>Pin bias functions</title> <p> Implement the pin bias
functions. </p> <ul>
<li><p> Implement <xref href="GUID-2179ABA4-EF54-31B4-876D-35DE3AED4486.dita"><apiname>SetPinBias()</apiname></xref> for each value
of the enumeration <xref href="GUID-58D2511D-99F1-361B-875C-0A0C32775A3F.dita"><apiname>TGpioBias</apiname></xref>. </p> <p>
Only implement this function to return <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref> if
the pin has a programmable device to stabilise its electric state.
Otherwise just implement it with return value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.
</p><ul>
<li><p> Implement <xref href="GUID-2179ABA4-EF54-31B4-876D-35DE3AED4486.dita"><apiname>SetPinBias()</apiname></xref> with
<codeph>aBias</codeph> containing <xref href="GUID-41EC1BCD-EEE6-301F-84F5-5CED9F444991.dita"><apiname>ENoDrive</apiname></xref> and
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p><p>
Disable any resistor or weak drive forcing the pin to a
default electrical state. </p> </li>
<li><p> Implement <xref href="GUID-2179ABA4-EF54-31B4-876D-35DE3AED4486.dita"><apiname>SetPinBias()</apiname></xref> with
<codeph>aBias</codeph> == <xref href="GUID-94DC7B4C-A782-3881-AC16-D982F206057A.dita"><apiname>EPullDown</apiname></xref> and return
value .<xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Cause the pin to default to its low electrical state by
pull-down resistor, weak drive or other means. </p> </li>
<li><p> Implement <xref href="GUID-2179ABA4-EF54-31B4-876D-35DE3AED4486.dita"><apiname>SetPinBias()</apiname></xref> with
<codeph>aBias</codeph> == <xref href="GUID-EFC660F1-A375-304B-9866-C937D2A36AD9.dita"><apiname>EPullUp</apiname></xref> and return
value .<xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Cause the pin to default to its high electrical state by
pull-down resistor, weak drive or other means. </p> </li>
<li><p> Implement <xref href="GUID-2179ABA4-EF54-31B4-876D-35DE3AED4486.dita"><apiname>SetPinBias()</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 setting the drive. </p> </li>
</ul> </li>
<li><p> Implement <xref href="GUID-727E0B20-32AF-3CBE-B0AC-6381C16955F1.dita"><apiname>GetPinBias()</apiname></xref> for each value
of the enumeration <xref href="GUID-58D2511D-99F1-361B-875C-0A0C32775A3F.dita"><apiname>TGpioBias</apiname></xref>. </p> <p>
Only implement this function to return <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref> if
the pin has a programmable device to stabilise its electric state.
Otherwise just implement it with return value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.
</p> <ul>
<li><p> Implement <xref href="GUID-727E0B20-32AF-3CBE-B0AC-6381C16955F1.dita"><apiname>GetPinBias()</apiname></xref> with
<codeph>aBias</codeph> containing <xref href="GUID-41EC1BCD-EEE6-301F-84F5-5CED9F444991.dita"><apiname>ENoDrive</apiname></xref> and
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Verify that any stabilising device on the pin has been
disabled. Set <codeph>aBias</codeph> to <xref href="GUID-41EC1BCD-EEE6-301F-84F5-5CED9F444991.dita"><apiname>ENoDrive</apiname></xref>.
</p> </li>
<li><p> Implement <xref href="GUID-727E0B20-32AF-3CBE-B0AC-6381C16955F1.dita"><apiname>GetPinBias()</apiname></xref> with
<codeph>aBias</codeph> containing <xref href="GUID-94DC7B4C-A782-3881-AC16-D982F206057A.dita"><apiname>EPullDown</apiname></xref> and
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Verify that the pin has been set to default to its low
electric state. Set <xref href="GUID-F9031EA4-2C8A-32CB-BB2B-26A20569866F.dita"><apiname>aBias</apiname></xref> to <xref href="GUID-94DC7B4C-A782-3881-AC16-D982F206057A.dita"><apiname>EPullDown</apiname></xref>.
</p> </li>
<li><p> Implement <xref href="GUID-727E0B20-32AF-3CBE-B0AC-6381C16955F1.dita"><apiname>GetPinBias()</apiname></xref> with
<codeph>aBias</codeph> containing <xref href="GUID-EFC660F1-A375-304B-9866-C937D2A36AD9.dita"><apiname>EPullUp</apiname></xref> and
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Verify that the pin has been set to default to its high
electric state. Set <xref href="GUID-F9031EA4-2C8A-32CB-BB2B-26A20569866F.dita"><apiname>aBias</apiname></xref> to <xref href="GUID-EFC660F1-A375-304B-9866-C937D2A36AD9.dita"><apiname>EPullUp</apiname></xref>.
</p> </li>
<li><p> Implement <xref href="GUID-727E0B20-32AF-3CBE-B0AC-6381C16955F1.dita"><apiname>GetPinBias()</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 reading the pin bias. </p> </li>
</ul> </li>
</ul> </section>
<section id="GUID-7ECD4CDD-1320-4AEA-AC9D-B2A473536C21"><title>Pin idle functions</title> <p> Implement the pin idle
functions. </p> <ul>
<li><p> Implement <xref href="GUID-0C5314C5-EE55-3974-8ED5-5AE26C0638F0.dita"><apiname>SetPinIdleConfigurationAndState()</apiname></xref>
with return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Return <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref> </p> </li>
<li><p> Implement <xref href="GUID-0C5314C5-EE55-3974-8ED5-5AE26C0638F0.dita"><apiname>SetPinIdleConfigurationAndState()</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 the idle state. </p> </li>
<li><p> Implement <xref href="GUID-4BF99D43-8F53-36B0-803D-FE86A1EF943A.dita"><apiname>GetPinIdleConfigurationAndState()</apiname></xref> with
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Return <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref> </p> </li>
<li><p> Implement <xref href="GUID-4BF99D43-8F53-36B0-803D-FE86A1EF943A.dita"><apiname>GetPinIdleConfigurationAndState()</apiname></xref> with
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if the pin does
not support the idle state. </p> </li>
</ul> </section>
<section id="GUID-1ECB1516-C554-4168-AE8C-FA4BDC7BF48F"><title>Interrupt functions</title> <p> Implement the interrupt
functions. </p> <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>
<section id="GUID-19811A8B-5A8F-4769-8686-1BB49C56532F"><title>Wakeup functions</title> <p> Implement the wakeup functions.
</p> <ul>
<li><p> Implement <xref href="GUID-1C41DDCD-7BE3-3BDA-A832-C2C9821AEB09.dita"><apiname>EnableWakeup()</apiname></xref> with return
value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Enable wakeup on the pin. </p> </li>
<li><p> Implement <xref href="GUID-21432D3C-90DA-35AA-AFB5-C7FF37ED0806.dita"><apiname>DisableWakeup()</apiname></xref> with return
value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Disable wakeup on the pin. </p> </li>
<li><p> Implement <xref href="GUID-D58B6C13-F3B0-3E18-A7ED-DE177BC2CCEB.dita"><apiname>IsWakeupEnabled()</apiname></xref> with
return value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p>
Verify that the pin supports wakeup and determine the wakeup
state. If is enabled set <xref href="GUID-28B9AB57-B1B6-3D84-A118-FAEA5AD2C23F.dita"><apiname>aEnable</apiname></xref> 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 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-1C41DDCD-7BE3-3BDA-A832-C2C9821AEB09.dita"><apiname>EnableWakeup()</apiname></xref> </p> </li>
<li><p> <xref href="GUID-21432D3C-90DA-35AA-AFB5-C7FF37ED0806.dita"><apiname>DisableWakeup()</apiname></xref> </p> </li>
<li><p> <xref href="GUID-D58B6C13-F3B0-3E18-A7ED-DE177BC2CCEB.dita"><apiname>IsWakeupEnabled()</apiname></xref> </p> </li>
</ul> <p> Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if the pin does
not support wakeups. </p> </li>
</ul> </section>
<section id="GUID-505B2E66-80A7-423D-8BE9-D5325D02F006"><title>Trigger functions</title> <p> Implement the trigger functions.
</p> <ul>
<li><p> Implement <xref href="GUID-29000C80-F7B6-3B7C-8944-F6BCAE2B6618.dita"><apiname>SetInterruptTrigger()</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. Set the interrupt trigger on the specified pin.
</p> </li>
<li><p> Implement <xref href="GUID-29000C80-F7B6-3B7C-8944-F6BCAE2B6618.dita"><apiname>SetInterruptTrigger()</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 interrupts. </p> </li>
<li><p> Implement <xref href="GUID-28F2D8DB-5D57-3199-9066-1B0252EE632E.dita"><apiname>SetWakeupTrigger()</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. Set the interrupt trigger on the specified pin.
The trigger should probably be edge detected. </p> </li>
<li><p> Implement <xref href="GUID-28F2D8DB-5D57-3199-9066-1B0252EE632E.dita"><apiname>SetWakeupTrigger()</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 wakeups. </p> </li>
</ul> </section>
<section id="GUID-718F1593-206E-4738-A34A-C9D3F52063EE"><title>Debounce functions</title> <p> Implement the debounce
functions. </p> <ul>
<li><p> Implement <xref href="GUID-837F3EC5-5379-3B88-B27B-A092E9F2E422.dita"><apiname>SetDebounceTime()</apiname></xref> with return
value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p> Verify
that the platform supports debouncing either by hardware or software.
Use the passed in value as the sampling interval in milliseconds. </p> <p>
Only implement this if the platform supports debouncing. </p> </li>
<li><p> Implement <xref href="GUID-72F9F470-4815-3674-A90F-1038C565F2E0.dita"><apiname>GetDebounceTime()</apiname></xref> with return
value <xref href="GUID-6CA4F1ED-7947-3087-B618-D35858FAA3BC.dita"><apiname>KErrNone</apiname></xref>. </p> <p> Determine
value in milliseconds of the sampling interval used in debouncing
and set aTime to that value. </p> <p> Only implement this
if the platform supports debouncing. </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-837F3EC5-5379-3B88-B27B-A092E9F2E422.dita"><apiname>SetDebounceTime() </apiname></xref> </p> </li>
<li><p> <xref href="GUID-72F9F470-4815-3674-A90F-1038C565F2E0.dita"><apiname>GetDebounceTime()</apiname></xref> </p> </li>
</ul> <p> Return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref> if the pin does
not support debouncing. </p> </li>
</ul> </section>
<section id="GUID-84ACB7AB-F6DE-42F5-8C89-C7598FBC7AC1"><title>Input/output</title> <p> Implement the input and output
state functions. </p> <ul>
<li><p> Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> for each value
of <xref href="GUID-7C1D78B4-9897-3C38-8EE7-7C311B885B0B.dita"><apiname>TGpioState</apiname></xref>. </p> <ul>
<li><p> Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with
<codeph>aState</codeph> == <xref href="GUID-ABF52F3A-CDC3-3AC6-89ED-FB7F5B781A25.dita"><apiname>ELow</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 being used as a binary output. Set it
to its low electric state. </p> </li>
<li><p> Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with
<codeph>aState</codeph> == <xref href="GUID-28B7F356-760B-38EA-90B1-AD3594375CBC.dita"><apiname>EHigh</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 being used as a binary output. Set it
to its high electric state. </p> </li>
<li><p> Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with
<codeph>aState</codeph> == <xref href="GUID-A538A8AF-DA50-3641-A794-19CAFF5B28F2.dita"><apiname>EDefaultIdleState</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 being used as a binary output. Set its
electric state to its default idle state. </p> </li>
<li><p> Implement <xref href="GUID-EB28CB99-7191-345B-90FC-7708E9D190C7.dita"><apiname>SetOutputState()</apiname></xref> with
return value <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>.
</p> <p> If the specified electric state is not supported
return <xref href="GUID-F89DA3F0-2A48-3F9B-8F08-29350E92D0E4.dita"><apiname>KErrNotSupported</apiname></xref>. </p> </li>
</ul> </li>
<li><p> Implement <xref href="GUID-E88C05CA-8882-3C6A-9B64-8048DB7DA622.dita"><apiname>GetOutputState()</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 a binary output. Determine its electric
state and set <codeph>aState</codeph> to the appropriate value of
<xref href="GUID-7C1D78B4-9897-3C38-8EE7-7C311B885B0B.dita"><apiname>TGpioState</apiname></xref>. </p> </li>
<li><p> Implement <xref href="GUID-9BFB4B87-1400-33C0-B116-AC6FA349BE1E.dita"><apiname>GetInputState()</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 a binary input. Determine its electric
state and set <codeph>aState</codeph> to the appropriate value of
<xref href="GUID-7C1D78B4-9897-3C38-8EE7-7C311B885B0B.dita"><apiname>TGpioState</apiname></xref>. </p> </li>
</ul></section>
<section id="GUID-DF48097B-9247-4817-9651-71C715FF5E09"><title>Static extension</title> <ul>
<li><p> Implement <xref href="GUID-821EF2E4-8DC9-3058-8CFD-53F3268264ED.dita"><apiname>StaticExtension()</apiname></xref> if necessary.
</p> </li>
</ul></section>
</conbody><related-links>
<link href="GUID-0E15C8C4-E511-569F-8AB4-895CA00331AB.dita"><linktext>GPIO Features</linktext>
</link>
<link href="GUID-745273E3-BB3A-59BF-9C33-6C8BB3D850A9.dita"><linktext>GPIO Design
Considerations</linktext></link>
</related-links></concept>