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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-9986DCC6-EE73-59FB-BDAC-9B09DC64FBCE" xml:lang="en"><title>Client of Master Channel Tutorial</title><shortdesc>Describes a simple implementation of a client using the |
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13 master channel functionality.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>This document describes a simple implementation of an IIC client |
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15 using the master channel functionality. </p> |
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16 <section id="GUID-A16020C1-28AC-4B14-9ADD-EEDD9C8EC65D"><title>Purpose</title> <p>This tutorial explains how to use the IIC platform service API |
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17 as a master and to communicate with a peripheral using half-duplex. </p> <p><b>Intended Audience</b> </p> <p>Device driver writers. </p> <p><b>Required Background</b> </p> <p>Before you start, you must: </p> <ul> |
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18 <li id="GUID-E339C63B-A5B2-535A-9EEB-E42F5913695F"><p>Have installed |
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19 the platform specific implementation of IIC channels that is required |
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20 to support the IIC platform service API. </p> </li> |
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21 <li id="GUID-BF87DA07-52AD-5B46-BA69-61AB6E23CA38"><p>Include the <filepath>IIC.dll</filepath> in the <filepath>kernel.iby</filepath> file. </p> </li> |
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22 <li id="GUID-DE66833F-6DE6-5068-BE7B-A748ABFE9915"><p>Include the <filepath>iic.h</filepath> and <filepath>iic_channel.h</filepath> header files. </p> </li> |
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23 </ul> <p> <note> The code example fragments are for synchronous operation. |
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24 For asynchronous operation, the buffers must be allocated on the heap. </note></p> </section> |
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25 <section id="GUID-420879EF-296C-4AB3-9B89-0C5BF6781206"><title>Implementing |
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26 the IIC platform service</title> <p>The Following tasks will be covered |
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27 in this tutorial: </p> <ul> |
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28 <li id="GUID-FF0DF82E-6D88-5C58-844C-2E1036816FAD"><p>Performing read/write |
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29 operations. </p> </li> |
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30 </ul> <p><b>Basic Procedure</b> </p> <p><note> The implementation |
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31 on which the following code examples are based is implemented IIC |
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32 via a SPI bus. On hardware with dedicated IIC ports, the IIC port |
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33 would be specified and the header data type would be TConfigIICV01.</note></p><p>The high level steps to performing read/write operations are |
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34 shown here: </p> <ol id="GUID-0080AB2C-6DC5-5128-B2FB-7E1D81859F7B"> |
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35 <li id="GUID-3C607C4B-20B8-5ED7-8A82-BF75CC2C5286"><p>First set the |
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36 bus type, the channel number and the slave address. </p> <p>An example |
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37 of this is : </p> <codeblock id="GUID-A66F8DD0-A870-5210-9AAB-D3B837D0E831" xml:space="preserve">// Configure the port. |
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38 busId.SetBusType(DIicBusChannel::ESpi); // Specify which multi-wire bus is to be used. in this example, SPI. |
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39 busId.SetChanNum(0); // Set the channel number. |
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40 busId.SetSlaveAddr(13); // Set the slave address. </codeblock> </li> |
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41 <li id="GUID-27D5A0ED-818B-51AE-BB48-32929DB3E134"><p>Configure the |
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42 channel. </p> <p>An example of which, is : </p> <codeblock id="GUID-43A34CF2-6324-5026-BC9E-28CE4B8D95A6" xml:space="preserve">// create header - this configures a SPI port. |
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43 const TConfigSpiV01 TestHeader = |
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44 { |
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45 ESpiWordWidth_8, // Set the word width. In this example, 8 bits. |
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46 260000, // Set the clock speed of the port. In this example, 260KHz. |
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47 ESpiPolarityLowRisingEdge, // Set the clock mode value. In this example, Active high, odd edges. |
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48 500, // Set the timeout period. In this example, 500msec. |
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49 EBigEndian, // Set which endian is to be used. In this example, BigEndian is used. |
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50 EMsbFirst, // Set which bit order is to be used. In this example, the Msb is first. |
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51 0, // Set the number of transaction wait cycles. In this example, 0. |
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52 ESpiCSPinActiveLow // Set the Chip select active mode. In this example, chip select is active low. |
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53 };</codeblock> </li> |
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54 <li id="GUID-6748A0B1-6A37-50AB-9D93-A230F419059A"><p>Make linked |
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55 lists of the transfers that are to be carried out. </p> <p>An example |
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56 of this is : </p> <codeblock id="GUID-C112BD53-C69C-595B-8452-82826AEC37B3" xml:space="preserve">// Set the transaction header. |
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57 TPckgBuf<TConfigSpiV01> header(TestHeader); |
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58 |
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59 // Set up a transmit transaction. |
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60 // This txTransfer buffer acts as the start of the transaction linked list. |
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61 TIicBusTransfer txTransfer(TIicBusTransfer::EMasterWrite, 8, &txTransferBuf); |
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62 |
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63 // Set up a receive transaction. |
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64 TIicBusTransfer rxTransfer(TIicBusTransfer::EMasterRead, 8, &rxTransferBuf); |
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65 |
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66 // Add to the receive transaction to the transaction linked list. |
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67 txTransfer.LinkAfter(&rxTransfer); |
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68 |
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69 // Create a transaction using header and the transaction linked list. |
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70 TIicBusTransaction transaction(&header, &txTransfer);</codeblock> </li> |
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71 <li id="GUID-B750A2D0-CFE2-584F-B2CF-5F19293B88BC"><p>Use the <xref href="GUID-69949E47-8FDF-3651-BEEF-43726EBEB5FF.dita#GUID-69949E47-8FDF-3651-BEEF-43726EBEB5FF/GUID-A1E7014A-6554-3D10-85E8-0DA839779800"><apiname>IicBus::QueueTransaction()</apiname></xref> method, specifying the configuration |
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72 of the port and the start location of the transaction linked lists. |
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73 This queues the transactions on to the selected IIC channel. </p> <p>An example of this is : </p> <codeblock id="GUID-5F929F5F-D8B3-5471-B65A-86D5D9DC8D7C" xml:space="preserve">// Queue the transaction. |
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74 // Once this command has been executed, the value of r should be KErrNone. |
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75 r = IicBus::QueueTransaction(busId.GetConfig(), &transaction);</codeblock> </li> |
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76 </ol> </section> |
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77 </conbody><related-links> |
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78 <link href="GUID-F461CBB3-F8D1-5961-AD51-5741143A1CB1.dita"><linktext>Client |
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79 of Slave Channel Tutorial</linktext></link> |
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80 <link href="GUID-B2F86F54-EF50-56DB-ADF7-15325AC9324D.dita"><linktext>IIC |
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81 Concepts</linktext></link> |
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82 <link href="GUID-3A30DA16-ECA8-5639-A9DC-6BE2AD55420B.dita"><linktext>I2C |
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83 Technology Guide</linktext></link> |
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84 </related-links></concept> |