82 lines
2 KiB
C
82 lines
2 KiB
C
/*
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* Driver for BH1750 light sensor
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*
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* Part of esp-open-rtos
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* Copyright (C) 2017 Andrej Krutak <dev@andree.sk>
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* BSD Licensed as described in the file LICENSE
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*
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* ROHM Semiconductor bh1750fvi-e.pdf
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*/
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#ifndef EXTRAS_BH1750_H_
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#define EXTRAS_BH1750_H_
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#include <stdint.h>
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#include <stdbool.h>
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#include <time.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Possible chip addresses */
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#define BH1750_ADDR_LO 0x23 // ADDR pin floating/low
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#define BH1750_ADDR_HI 0x5c
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/* Configuration options */
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// No active state
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#define BH1750_POWER_DOWN 0x00
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// Wating for measurement command
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#define BH1750_POWER_ON 0x01
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// Reset data register value - not accepted in POWER_DOWN mode
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#define BH1750_RESET 0x07
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/* Measurement modes */
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#define BH1750_CONTINUOUS_MODE 0x10
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#define BH1750_ONE_TIME_MODE 0x20
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// Start measurement at 1 lx resolution (measurement time typically 120ms)
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#define BH1750_HIGH_RES_MODE 0x00
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// Start measurement at 0.5 lx resolution (measurement time typically 120ms)
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#define BH1750_HIGH_RES_MODE2 0x01
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// Start measurement at 4 lx resolution (measurement time typically 16ms)
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#define BH1750_LOW_RES_MODE 0x03
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/* Adjust measurement time to account for optical window size (see datasheet).
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* Procedure from datasheet suggests order Hi, Low and finally measurement mode
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*/
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#define BH1750_MEASURE_TIME_HI(mt) (0x40 | (((mt) >> 5) & 0x7))
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#define BH1750_MEASURE_TIME_LO(mt) (0x60 | ((mt) & 0x1f))
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#define BH1750_DEFAULT_MEASURE_TIME 0x45
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/**
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* Configure the device.
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* @param addr Device address
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* @param mode Combination of BH1750_* flags
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*
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* May be called multiple times e.g. to configure the measurement time and
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* the readout mode afterwards - or if one time mode is used consecutively.
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*
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* Example: BH1750_ADDR_LO, BH1750_CONTINUOUS_MODE | BH1750_HIGH_RES_MODE
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*/
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void bh1750_configure(uint8_t addr, uint8_t mode);
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/**
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* Read LUX value from the device.
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*
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* @param addr Device address
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* @returns read value in lux units
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*/
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uint16_t bh1750_read(uint8_t addr);
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#ifdef __cplusplus
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}
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#endif
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#endif /* EXTRAS_BH1750_H_ */
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