osd-contiki/platform/mbxxx/dev/i2c.c

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/*
* Copyright (c) 2013, IDentification Automation Laboratory
* IDALab (http://www.idalab.unisalento.it)
* Department of Innovation Engineering - University of Salento
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/**
* \file i2c.c
* \brief I2C bus master driver for mbxxx platform.
* \author Maria Laura Stefanizzi <laura28582@gmail.com>
* \date 2013-11-20
*/
#include <stdio.h>
#include <contiki.h>
#include "dev/i2c.h"
#include PLATFORM_HEADER
#define WAIT_FIN_SC2(FLAG) while(!SC2_STAT(FLAG)) {}
/**
* Configure serial controller in I2C mode and set I2C speed.
*/
void
i2c_enable(void)
{
/* Configure serial controller to I2C mode */
SC2_MODE = SC2_MODE_I2C;
/*
* The SCL is produced by dividing down 12MHz according to
* this equation:
* Rate = 12 MHz / ( (LIN + 1) * (2^EXP) )
*
* Configure rate registers for Fast Mode operation (400 kbps)
*/
SC2_RATELIN = 14;
SC2_RATEEXP = 1;
/* Reset control registers */
SC2_TWICTRL1 = SC2_TWICTRL1_RESET;
SC2_TWICTRL2 = SC2_TWICTRL2_RESET;
}
/**
* Configure serial controller in disabled mode
*/
void
i2c_disable(void)
{
SC2_MODE = SC2_MODE_DISABLED;
}
/**
* Generate I2C START condition
*/
void
i2c_start(void)
{
SC2_TWICTRL1 |= SC_TWISTART;
WAIT_FIN_SC2(SC_TWICMDFIN);
}
/**
* Generate I2C STOP condition
*/
void
i2c_stop(void)
{
SC2_TWICTRL1 |= SC_TWISTOP;
WAIT_FIN_SC2(SC_TWICMDFIN);
}
/**
* Send a byte to I2C bus
* @param data The data that must be sent
*/
void
i2c_write(uint8_t data)
{
SC2_DATA = data;
/* Configure control register 1 for byte transmission */
SC2_TWICTRL1 |= SC_TWISEND;
WAIT_FIN_SC2(SC_TWITXFIN);
}
/**
* Read a byte from I2C bus
* @param ack If true enable ACK generation after byte reception
* @return The received byte
*/
uint8_t
i2c_read(int ack)
{
if(ack) {
/* Enable ACK generation after current received byte */
SC2_TWICTRL2 |= SC_TWIACK;
} else {
/* Disable ACK generation */
SC2_TWICTRL2 &= ~SC_TWIACK;
}
/* Configure control register 1 for byte reception */
SC2_TWICTRL1 |= SC_TWIRECV;
WAIT_FIN_SC2(SC_TWIRXFIN);
return SC2_DATA;
}