bh1750fvi.c
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/*
* Copyright (C) 2016 Freie Universität Berlin
*
* 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 drivers_bh1750fvi
* @{
*
* @file
* @brief BH1750FVI ambient light sensor driver implementation
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include <stdio.h>
#include "xtimer.h"
#include "bh1750fvi.h"
#include "bh1750fvi_internal.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
int bh1750fvi_init(bh1750fvi_t *dev, bh1750fvi_params_t *params)
{
int res;
/* initialize the device descriptor */
dev->i2c = params->i2c;
dev->addr = params->addr;
/* initialize the I2C bus */
i2c_acquire(dev->i2c);
i2c_init_master(dev->i2c, params->clk);
/* send a power down command to make sure we can speak to the device */
res = i2c_write_byte(dev->i2c, dev->addr, OP_POWER_DOWN);
i2c_release(dev->i2c);
if (res < 0) {
return BH1750FVI_ERR_I2C;
}
return BH1750FVI_OK;
}
uint16_t bh1750fvi_sample(bh1750fvi_t *dev)
{
uint32_t tmp;
uint8_t raw[2];
/* power on the device and send single H-mode measurement command */
DEBUG("[bh1750fvi] sample: triggering a conversion\n");
i2c_acquire(dev->i2c);
i2c_write_byte(dev->i2c, dev->addr, OP_POWER_ON);
i2c_write_byte(dev->i2c, dev->addr, OP_SINGLE_HRES1);
i2c_release(dev->i2c);
/* wait for measurement to complete */
xtimer_usleep(DELAY_HMODE);
/* read the results */
DEBUG("[bh1750fvi] sample: reading the results\n");
i2c_acquire(dev->i2c);
i2c_read_bytes(dev->i2c, dev->addr, raw, 2);
i2c_release(dev->i2c);
/* and finally we calculate the actual LUX value */
tmp = (raw[0] << 24) | (raw[1] << 16);
tmp /= RES_DIV;
return (uint16_t)(tmp);
}