lis3mdl.c
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/*
* Copyright (C) 2015 HAW Hamburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup driver_lis3mdl
* @{
*
* @file
* @brief Device driver implementation for the LIS3MDL 3-axis magnetometer
*
* @author René Herthel <rene-herthel@outlook.de>
*
* @}
*/
#include "lis3mdl.h"
#include "include/lis3mdl-internal.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#define MASK_INT16_MSB (0x8000)
#define MASK_INT16_NMSB (0x7FFF)
#define TEMP_DIVIDER (16)
#define TEMP_OFFSET (25)
#define GAUSS_DIVIDER (1000)
/**
* @brief Takes an unsigned value representing a two's complement number
* and returns the signed number it represents
*
* @param[in] value value which represents a two's complement number
*
* @return the converted signed number of 'value'
*/
static inline int16_t _twos_complement(int16_t value)
{
if (value & MASK_INT16_MSB) {
value = ~(value & MASK_INT16_NMSB) + 1;
return ~(value & MASK_INT16_NMSB);
}
else {
return value;
}
}
int lis3mdl_init(lis3mdl_t *dev,
i2c_t i2c,
uint8_t address,
lis3mdl_xy_mode_t xy_mode,
lis3mdl_z_mode_t z_mode,
lis3mdl_odr_t odr,
lis3mdl_scale_t scale,
lis3mdl_op_t op_mode) {
uint8_t tmp;
dev->i2c = i2c;
dev->addr = address;
i2c_acquire(dev->i2c);
if (i2c_init_master(i2c, I2C_SPEED_NORMAL) < 0) {
DEBUG("LIS3MDL: Master initialization failed\n");
return -1;
}
i2c_read_reg(dev->i2c, dev->addr, LIS3DML_WHO_AM_I_REG, &tmp);
if (tmp != LIS3MDL_CHIP_ID) {
DEBUG("LIS3MDL: Identification failed\n");
return -1;
}
tmp = ( LIS3MDL_MASK_REG1_TEMP_EN /* enable temperature sensor */
| xy_mode /* set x-, y-axis operative mode */
| odr); /* set output data rate */
i2c_write_reg(dev->i2c, dev->addr, LIS3MDL_CTRL_REG1, tmp);
/* set Full-scale configuration */
i2c_write_reg(dev->i2c, dev->addr, LIS3MDL_CTRL_REG2, scale);
/* set continuous-conversion mode */
i2c_write_reg(dev->i2c, dev->addr, LIS3MDL_CTRL_REG3, op_mode);
/* set z-axis operative mode */
i2c_write_reg(dev->i2c, dev->addr, LIS3MDL_CTRL_REG4, z_mode);
i2c_release(dev->i2c);
return 0;
}
void lis3mdl_read_mag(lis3mdl_t *dev, lis3mdl_3d_data_t *data)
{
uint8_t tmp[2] = {0, 0};
i2c_acquire(dev->i2c);
i2c_read_regs(dev->i2c, dev->addr, LIS3MDL_OUT_X_L_REG, &tmp[0], 2);
data->x_axis = (tmp[1] << 8) | tmp[0];
i2c_read_regs(dev->i2c, dev->addr, LIS3MDL_OUT_Y_L_REG, &tmp[0], 2);
data->y_axis = (tmp[1] << 8) | tmp[0];
i2c_read_regs(dev->i2c, dev->addr, LIS3MDL_OUT_Z_L_REG, &tmp[0], 2);
data->z_axis = (tmp[1] << 8) | tmp[0];
data->x_axis = _twos_complement(data->x_axis);
data->y_axis = _twos_complement(data->y_axis);
data->z_axis = _twos_complement(data->z_axis);
/* Divide the raw data by 1000 to geht [G] := Gauss */
data->x_axis /= GAUSS_DIVIDER;
data->y_axis /= GAUSS_DIVIDER;
data->z_axis /= GAUSS_DIVIDER;
i2c_release(dev->i2c);
}
void lis3mdl_read_temp(lis3mdl_t *dev, int16_t *value)
{
i2c_acquire(dev->i2c);
i2c_read_regs(dev->i2c, dev->addr, LIS3MDL_TEMP_OUT_L_REG, (uint8_t*)value, 2);
i2c_release(dev->i2c);
*value = _twos_complement(*value);
*value = (TEMP_OFFSET + (*value / TEMP_DIVIDER));
}
void lis3mdl_enable(lis3mdl_t *dev)
{
i2c_acquire(dev->i2c);
/* Z-axis medium-power mode */
i2c_write_reg(dev->i2c, dev->addr,
LIS3MDL_CTRL_REG3, LIS3MDL_MASK_REG3_Z_MEDIUM_POWER);
i2c_release(dev->i2c);
}
void lis3mdl_disable(lis3mdl_t *dev)
{
uint8_t tmp = ( LIS3MDL_MASK_REG3_LOW_POWER_EN /**< enable power-down mode */
| LIS3MDL_MASK_REG3_Z_LOW_POWER); /**< Z-axis low-power mode */
i2c_acquire(dev->i2c);
i2c_write_reg(dev->i2c, dev->addr, LIS3MDL_CTRL_REG3, tmp);
i2c_release(dev->i2c);
}