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added i2c.c that I forgot earlier

This commit is contained in:
Michael Ossmann 2012-06-04 17:57:49 -06:00
parent 5698016877
commit e7941eace9
1 changed files with 94 additions and 0 deletions
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lib/lpc43xx/i2c.c Normal file
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/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2012 Michael Ossmann <mike@ossmann.com>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* This is a very minimal I2C driver just to make sure we can get the
* peripheral working.
*/
#include <libopencm3/lpc43xx/i2c.h>
#include <libopencm3/lpc43xx/scu.h>
#include <libopencm3/lpc43xx/cgu.h>
void i2c0_init(void)
{
/* enable input on SCL and SDA pins */
SCU_SFSI2C0 = SCU_I2C0_NOMINAL;
/* use PLL1 as clock source for APB1 (including I2C0) */
CGU_BASE_APB1_CLK = (CGU_SRC_PLL1 << CGU_BASE_CLK_SEL_SHIFT);
/* FIXME assuming we're on IRC at 96 MHz */
/* 400 kHz I2C */
/*
I2C0_SCLH = 120;
I2C0_SCLL = 120;
*/
/* 100 kHz I2C */
I2C0_SCLH = 480;
I2C0_SCLL = 480;
/* FIXME not sure why this appears to run at about 290 kHz */
/* clear the control bits */
I2C0_CONCLR = (I2C_CONCLR_AAC | I2C_CONCLR_SIC
| I2C_CONCLR_STAC | I2C_CONCLR_I2ENC);
/* enable I2C0 */
I2C0_CONSET = I2C_CONSET_I2EN;
}
/* transmit start bit */
void i2c0_tx_start(void)
{
I2C0_CONCLR = I2C_CONCLR_SIC;
I2C0_CONSET = I2C_CONSET_STA;
while (!(I2C0_CONSET & I2C_CONSET_SI));
I2C0_CONCLR = I2C_CONCLR_STAC;
}
/* transmit data byte */
void i2c0_tx_byte(u8 byte)
{
if (I2C0_CONSET & I2C_CONSET_STA)
I2C0_CONCLR = I2C_CONCLR_STAC;
I2C0_DAT = byte;
I2C0_CONCLR = I2C_CONCLR_SIC;
while (!(I2C0_CONSET & I2C_CONSET_SI));
}
/* receive data byte */
u8 i2c0_rx_byte(void)
{
if (I2C0_CONSET & I2C_CONSET_STA)
I2C0_CONCLR = I2C_CONCLR_STAC;
I2C0_CONCLR = I2C_CONCLR_SIC;
while (!(I2C0_CONSET & I2C_CONSET_SI));
return I2C0_DAT;
}
/* transmit stop bit */
void i2c0_stop(void)
{
if (I2C0_CONSET & I2C_CONSET_STA)
I2C0_CONCLR = I2C_CONCLR_STAC;
I2C0_CONSET = I2C_CONSET_STO;
I2C0_CONCLR = I2C_CONCLR_SIC;
}