i2c_atmel.c

最新版IAR FOR ARM（EWARM）5.11中的代码例子

//*****************************************************************************
//
// i2c_atmel.c - I2C master example.
//
// Copyright (c) 2005-2007 Luminary Micro, Inc.  All rights reserved.
// 
// Software License Agreement
// 
// Luminary Micro, Inc. (LMI) is supplying this software for use solely and
// exclusively on LMI's microcontroller products.
// 
// The software is owned by LMI and/or its suppliers, and is protected under
// applicable copyright laws.  All rights are reserved.  You may not combine
// this software with "viral" open-source software in order to form a larger
// program.  Any use in violation of the foregoing restrictions may subject
// the user to criminal sanctions under applicable laws, as well as to civil
// liability for the breach of the terms and conditions of this license.
// 
// THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
// OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
// LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
// CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 1952 of the Stellaris Peripheral Driver Library.
//
//*****************************************************************************

#include "../../../hw_ints.h"
#include "../../../hw_memmap.h"
#include "../../../hw_types.h"
#include "../../../src/debug.h"
#include "../../../src/gpio.h"
#include "../../../src/i2c.h"
#include "../../../src/interrupt.h"
#include "../../../src/sysctl.h"
#include "../../../utils/diag.h"
#include "../pdc.h"

//*****************************************************************************
//
//! \addtogroup dk_lm3s815_list
//! <h1>I2C (i2c_atmel)</h1>
//!
//! This example application uses the I2C master to communicate with the Atmel
//! AT24C08A EEPROM that is on the development board.  The first sixteen bytes
//! of the EEPROM are erased and then programmed with an incrementing sequence.
//! The data is then read back to verify its correctness.  The transfer is
//! managed by an interrupt handler in response to the I2C interrupt; since a
//! sixteen-byte read at a 100 kHz I2C bus speed takes almost 2 ms, this allows
//! a lot of other processing to occur during the transfer (though that time is
//! not utilized by this example).
//!
//! In order for this example to work properly, the I2C_SCL (JP14), I2C_SDA
//! (JP13), and I2CM_A2 (JP11) jumpers must be installed on the board, and the
//! I2CM_WP (JP12) jumper must be removed.
//
//*****************************************************************************

//*****************************************************************************
//
// The states in the interrupt handler state machine.
//
//*****************************************************************************
#define STATE_IDLE         0
#define STATE_WRITE_NEXT   1
#define STATE_WRITE_FINAL  2
#define STATE_WAIT_ACK     3
#define STATE_SEND_ACK     4
#define STATE_READ_ONE     5
#define STATE_READ_FIRST   6
#define STATE_READ_NEXT    7
#define STATE_READ_FINAL   8
#define STATE_READ_WAIT    9

//*****************************************************************************
//
// The variables that track the data to be transmitted or received.
//
//*****************************************************************************
static unsigned char *g_pucData = 0;
static unsigned long g_ulCount = 0;

//*****************************************************************************
//
// The current state of the interrupt handler state machine.
//
//*****************************************************************************
static volatile unsigned long g_ulState = STATE_IDLE;

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif

//*****************************************************************************
//
// The I2C interrupt handler.
//
//*****************************************************************************
void
I2CIntHandler(void)
{
    //
    // Clear the I2C interrupt.
    //
    I2CMasterIntClear(I2C0_MASTER_BASE);

    //
    // Determine what to do based on the current state.
    //
    switch(g_ulState)
    {
        //
        // The idle state.
        //
        case STATE_IDLE:
        {
            //
            // There is nothing to be done.
            //
            break;
        }

        //
        // The state for the middle of a burst write.
        //
        case STATE_WRITE_NEXT:
        {
            //
            // Write the next byte to the data register.
            //
            I2CMasterDataPut(I2C0_MASTER_BASE, *g_pucData++);
            g_ulCount--;

            //
            // Continue the burst write.
            //
            I2CMasterControl(I2C0_MASTER_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);

            //
            // If there is one byte left, set the next state to the final write
            // state.
            //
            if(g_ulCount == 1)
            {
                g_ulState = STATE_WRITE_FINAL;
            }

            //
            // This state is done.
            //
            break;
        }

        //
        // The state for the final write of a burst sequence.
        //
        case STATE_WRITE_FINAL:
        {
            //
            // Write the final byte to the data register.
            //
            I2CMasterDataPut(I2C0_MASTER_BASE, *g_pucData++);
            g_ulCount--;

            //
            // Finish the burst write.
            //
            I2CMasterControl(I2C0_MASTER_BASE,
                             I2C_MASTER_CMD_BURST_SEND_FINISH);

            //
            // The next state is to wait for the burst write to complete.
            //
            g_ulState = STATE_SEND_ACK;

            //
            // This state is done.
            //
            break;
        }

        //
        // Wait for an ACK on the read after a write.
        //
        case STATE_WAIT_ACK:
        {
            //
            // See if there was an error on the previously issued read.
            //
            if(I2CMasterErr(I2C0_MASTER_BASE) == I2C_MASTER_ERR_NONE)
            {
                //
                // Read the byte received.
                //
                I2CMasterDataGet(I2C0_MASTER_BASE);

                //
                // There was no error, so the state machine is now idle.
                //
                g_ulState = STATE_IDLE;

                //
                // This state is done.
                //
                break;
            }

            //
            // Fall through to STATE_SEND_ACK.
            //
        }

        //
        // Send a read request, looking for the ACK to indicate that the write
        // is done.
        //
        case STATE_SEND_ACK:
        {
            //
            // Put the I2C master into receive mode.
            //
            I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, 0x50, true);

            //
            // Perform a single byte read.
            //
            I2CMasterControl(I2C0_MASTER_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

            //
            // The next state is the wait for the ack.
            //
            g_ulState = STATE_WAIT_ACK;

            //
            // This state is done.
            //
            break;
        }

        //
        // The state for a single byte read.
        //
        case STATE_READ_ONE:
        {
            //
            // Put the I2C master into receive mode.
            //
            I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, 0x50, true);

            //
            // Perform a single byte read.
            //
            I2CMasterControl(I2C0_MASTER_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

            //
            // The next state is the wait for final read state.
            //
            g_ulState = STATE_READ_WAIT;

            //
            // This state is done.
            //
            break;
        }

        //
        // The state for the start of a burst read.
        //
        case STATE_READ_FIRST:
        {
            //
            // Put the I2C master into receive mode.
            //
            I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, 0x50, true);

            //
            // Start the burst receive.
            //
            I2CMasterControl(I2C0_MASTER_BASE,
                             I2C_MASTER_CMD_BURST_RECEIVE_START);

            //
            // The next state is the middle of the burst read.
            //