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<concept xml:lang="en" id="GUID-9986DCC6-EE73-59FB-BDAC-9B09DC64FBCE"><title>Client of IIC Master Channel Implementation Tutorial</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>This document describes a simple implementation of an IIC client using the master channel functionality. </p> <section><title>Purpose</title> <p>This tutorial explains how to use the IIC master side API 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><li id="GUID-E339C63B-A5B2-535A-9EEB-E42F5913695F"><p>Have installed the platform specific implementation of IIC channels that is required to support the IIC API. </p> </li> <li id="GUID-BF87DA07-52AD-5B46-BA69-61AB6E23CA38"><p>The IIC.dll has been included in the kernel.iby file. </p> </li> <li id="GUID-DE66833F-6DE6-5068-BE7B-A748ABFE9915"><p>Include the iic.h and iic_channel.h header files. </p> </li> </ul> <p> <note>Note:</note> The code example fragments are for synchronous operation. For asynchronous operation, the buffers must be allocated on the heap. </p> </section> <section><title>Implementing IIC user-side</title> <p>The Following tasks will be covered in this tutorial: </p> <ul><li id="GUID-FF0DF82E-6D88-5C58-844C-2E1036816FAD"><p>Performing read/write operations. </p> </li> </ul> <p><b>Basic Procedure</b> </p> <p>The high level steps to performing read/write operations are shown here: </p> <ol id="GUID-0080AB2C-6DC5-5128-B2FB-7E1D81859F7B"><li id="GUID-3C607C4B-20B8-5ED7-8A82-BF75CC2C5286"><p>First set the bus type, the channel number and the slave address. </p> <p>An example of this, is : </p> <codeblock id="GUID-A66F8DD0-A870-5210-9AAB-D3B837D0E831" xml:space="preserve">// Configure the port.

    busId.SetBusType(DIicBusChannel::ESpi);        // Specify which multi-wire bus is to be used. in this example, SPI.

    busId.SetChanNum(0);                                                                                    // Set the channel number.

    busId.SetSlaveAddr(13);                                                                     // Set the slave address. </codeblock> </li> <li id="GUID-27D5A0ED-818B-51AE-BB48-32929DB3E134"><p>Configure the 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.

    const TConfigSpiV01 TestHeader =

        {

        ESpiWordWidth_8,                                                 // Set the word width. In this example, 8 bits.

        260000,                                                                                     // Set the clock speed of the port. In this example, 260KHz.

        ESpiPolarityLowRisingEdge,         // Set the clock mode value. In this example, Active high, odd edges.

        500,                                                                                                 // Set the timeout period. In this example, 500msec.

        EBigEndian,                                                                     // Set which endian is to be used. In this example, BigEndian is used.

        EMsbFirst,                                                                         // Set which bit order is to be used. In this example, the Msb is first.

        0,                                                                                                         // Set the number of transaction wait cycles. In this example, 0.

        ESpiCSPinActiveLow                                         // Set the Chip select active mode. In this example, chip select is active low.

        };</codeblock> </li> <li id="GUID-6748A0B1-6A37-50AB-9D93-A230F419059A"><p>Make linked lists of the transfers that are to be carried out. </p> <p>An example of this, is : </p> <codeblock id="GUID-C112BD53-C69C-595B-8452-82826AEC37B3" xml:space="preserve">// Set the transaction header.

    TPckgBuf<TConfigSpiV01> header(TestHeader);

    // Set up a transmit transaction.

    // This txTransfer buffer acts as the start of the transaction linked list.

    TIicBusTransfer txTransfer(TIicBusTransfer::EMasterWrite, 8, &txTransferBuf);

    // Set up a receive transaction.

    TIicBusTransfer rxTransfer(TIicBusTransfer::EMasterRead, 8, &rxTransferBuf);

    // Add to the receive transaction to the transaction linked list.

    txTransfer.LinkAfter(&rxTransfer);

    // Create a transaction using header and the transaction linked list.

    TIicBusTransaction transaction(&amp;header, &amp;txTransfer);</codeblock> </li> <li id="GUID-B750A2D0-CFE2-584F-B2CF-5F19293B88BC"><p>Use the QueueTransaction method, specifying the configuration of the port and the start location of the transaction linked lists. This queues the transactions onto 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.

 // Once this command has been executed, the value of r should be KErrNone.

    r = IicBus::QueueTransaction(busId.GetConfig(), &amp;transaction);</codeblock> </li> </ol> </section> </conbody><related-links><link href="GUID-F461CBB3-F8D1-5961-AD51-5741143A1CB1.dita"><linktext>Client

                of Slave User Side Tutorial</linktext> </link> <link href="GUID-C0803997-F111-52C8-9F18-9138F02BCED5.dita"><linktext>IIC