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77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
/*
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* Copyright (C) 2016 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser General
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* Public License v2.1. See the file LICENSE in the top level directory for more
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* details.
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*/
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/**
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* @ingroup drivers_bh1750fvi
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* @{
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*
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* @file
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* @brief BH1750FVI ambient light sensor driver implementation
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include <stdio.h>
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#include "xtimer.h"
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#include "bh1750fvi.h"
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#include "bh1750fvi_internal.h"
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#define ENABLE_DEBUG 0
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#include "debug.h"
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int bh1750fvi_init(bh1750fvi_t *dev, const bh1750fvi_params_t *params)
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{
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int res;
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/* initialize the device descriptor */
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dev->i2c = params->i2c;
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dev->addr = params->addr;
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/* initialize the I2C bus */
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i2c_acquire(dev->i2c);
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/* send a power down command to make sure we can speak to the device */
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res = i2c_write_byte(dev->i2c, dev->addr, OP_POWER_DOWN, 0);
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i2c_release(dev->i2c);
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if (res < 0) {
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return BH1750FVI_ERR_I2C;
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}
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return BH1750FVI_OK;
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}
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uint16_t bh1750fvi_sample(const bh1750fvi_t *dev)
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{
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uint32_t tmp;
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uint8_t raw[2];
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/* power on the device and send single H-mode measurement command */
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DEBUG("[bh1750fvi] sample: triggering a conversion\n");
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i2c_acquire(dev->i2c);
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i2c_write_byte(dev->i2c, dev->addr, OP_POWER_ON, 0);
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i2c_write_byte(dev->i2c, dev->addr, OP_SINGLE_HRES1, 0);
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i2c_release(dev->i2c);
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/* wait for measurement to complete */
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xtimer_usleep(DELAY_HMODE);
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/* read the results */
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DEBUG("[bh1750fvi] sample: reading the results\n");
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i2c_acquire(dev->i2c);
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i2c_read_bytes(dev->i2c, dev->addr, raw, 2, 0);
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i2c_release(dev->i2c);
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/* and finally we calculate the actual LUX value */
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tmp = ((uint32_t)raw[0] << 24) | ((uint32_t)raw[1] << 16);
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tmp /= RES_DIV;
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return (uint16_t)(tmp);
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}
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