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