evmdm6437_i2c.c

evmdm6437_i2c的函数原型！！！！！！！！！！！！！！！

/*
 *  Copyright 2006 by Spectrum Digital Incorporated.
 *  All rights reserved. Property of Spectrum Digital Incorporated.
 */

/*
 *  I2C implementation
 *
 */

#include "evmdm6437_i2c.h"

Int32 i2c_timeout = 0x10000;

/* ------------------------------------------------------------------------ *
 *                                                                          *
 *  _I2C_init( )                                                            *
 *                                                                          *
 *      Enable and initalize the I2C module                                 *
 *      The I2C clk is set to run at 100 KHz                                *
 *                                                                          *
 * ------------------------------------------------------------------------ */
Int16 EVMDM6437_I2C_init( )
{
    I2C_ICMDR   = 0;                    // Reset I2C
    I2C_ICPSC   = 13;                   // Config prescaler for 27MHz
    I2C_ICCLKL  = 5;                    // Config clk LOW for 100 kHz
    I2C_ICCLKH  = 5;                    // Config clk HIGH for 100 kHz
    I2C_ICMDR  |= ICMDR_IRS;            // Release I2C from reset
    return 0;
}

/* ------------------------------------------------------------------------ *
 *                                                                          *
 *  _I2C_close( )                                                           *
 *                                                                          *
 * ------------------------------------------------------------------------ */
Int16 EVMDM6437_I2C_close( )
{
    I2C_ICMDR = 0;                      // Reset I2C
    return 0;
}

/* ------------------------------------------------------------------------ *
 *                                                                          *
 *  _I2C_reset( )                                                           *
 *                                                                          *
 * ------------------------------------------------------------------------ */
Int16 EVMDM6437_I2C_reset( )
{
    EVMDM6437_I2C_close( );
    EVMDM6437_I2C_init( );
    return 0;
}

/* ------------------------------------------------------------------------ *
 *                                                                          *
 *  _I2C_write( i2c_addr, data, len )                                       *
 *                                                                          *
 *      I2C write in Master mode                                            *
 *                                                                          *
 *      i2c_addr    <- I2C slave address                                    *
 *      data        <- I2C data ptr                                         *
 *      len         <- # of bytes to write                                  *
 *                                                                          *
 *      Returns:    0: PASS                                                 *
 *                 -1: FAIL Timeout                                         *
 *                                                                          *
 * ------------------------------------------------------------------------ */
Int16 EVMDM6437_I2C_write( Uint16 i2c_addr, Uint8* data, Uint16 len )
{
    Int32 timeout, i;

    I2C_ICCNT = len;                    // Set length
    I2C_ICSAR = i2c_addr;               // Set I2C slave address
    I2C_ICMDR = ICMDR_STT               // Set for Master Write
              | ICMDR_TRX
              | ICMDR_MST
              | ICMDR_IRS
              | ICMDR_FREE;

    _wait( 10 );                        // Short delay

    for ( i = 0 ; i < len ; i++ )
    {
        I2C_ICDXR = data[i];            // Write

        timeout = i2c_timeout;
        do
        {
            if ( timeout-- < 0 ) //if timeout,restart
            {
                EVMDM6437_I2C_reset( );
                return -1;
            }
        } while ( ( I2C_ICSTR & ICSTR_ICXRDY ) == 0 );// Wait for Tx Ready
    }

    I2C_ICMDR |= ICMDR_STP;             // Generate STOP

    return 0;
}

/* ------------------------------------------------------------------------ *
 *                                                                          *
 *  _I2C_read( i2c_addr, data, len )                                        *
 *                                                                          *
 *      I2C read in Master mode                                             *
 *                                                                          *
 *      i2c_addr    <- I2C slave address                                    *
 *      data        <- I2C data ptr                                         *
 *      len         <- # of bytes to write                                  *
 *                                                                          *
 *      Returns:    0: PASS                                                 *
 *                 -1: FAIL Timeout                                         *
 *                                                                          *
 * ------------------------------------------------------------------------ */
Int16 EVMDM6437_I2C_read( Uint16 i2c_addr, Uint8* data, Uint16 len )
{
    Int32 timeout, i;

    I2C_ICCNT = len;                    // Set length
    I2C_ICSAR = i2c_addr;               // Set I2C slave address
    I2C_ICMDR = ICMDR_STT               // Set for Master Read
              | ICMDR_MST
              | ICMDR_IRS
              | ICMDR_FREE;

    _wait( 10 );                        // Short delay

    for ( i = 0 ; i < len ; i++ )
    {
        timeout = i2c_timeout;
        do
        {
            if ( timeout-- < 0 )
            {
                EVMDM6437_I2C_reset( );
                return -1;
            }
        } while ( ( I2C_ICSTR & ICSTR_ICRRDY ) == 0 );// Wait for Rx Ready

        data[i] = I2C_ICDRR;            // Read
    }

    I2C_ICMDR |= ICMDR_STP;             // Generate STOP

    return 0;
}