bh1750 driver for ESP32

bh1750.c

#include "bh1750.h"
#include "driver/i2c.h"
#include "freertos/FreeRTOS.h"

#define AFTER_READ_KOEF 1.2

bool bh1750_op_cmd(uint8_t op) {
    i2c_cmd_handle_t cmd = i2c_cmd_link_create();
    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, BH1750_ADDRESS << 1 | I2C_MASTER_WRITE, true);
    i2c_master_write_byte(cmd, op, true);
    i2c_master_stop(cmd);

    esp_err_t ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000 / portTICK_PERIOD_MS);
    i2c_cmd_link_delete(cmd);

    return ret == ESP_OK;
}

bool bh1750_power_down() {
    return bh1750_op_cmd(BH1750_POWER_DOWN);
}

bool bh1750_power_on() {
    return bh1750_op_cmd(BH1750_POWER_ON);
}

bool bh1750_reset() {
    return bh1750_op_cmd(BH1750_RESET);
}

bool bh1750_set_mode(uint8_t mode) {
    return bh1750_op_cmd(mode);
}

uint16_t bh1750_read_light_level() {
    // read two bytes
    uint16_t level;

    i2c_cmd_handle_t cmd = i2c_cmd_link_create();
    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, BH1750_ADDRESS << 1 | I2C_MASTER_READ, true);
    i2c_master_read(cmd, (uint8_t*)&level, 2, I2C_MASTER_LAST_NACK);
    i2c_master_stop(cmd);

    esp_err_t ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000 / portTICK_PERIOD_MS);

    i2c_cmd_link_delete(cmd);

    if (ret != ESP_OK) {
        return -1;
    } else {
        return level / AFTER_READ_KOEF;
    }
}

bh1750.h

#ifndef BH1750_H
#define BH1750_H

#include <stdint.h>
#include <stdbool.h>

#define BH1750_ADDRESS 0x23

#define BH1750_POWER_DOWN 0x00
#define BH1750_POWER_ON 0x01
#define BH1750_RESET 0x07

// 120ms 1lx resolution
#define BH1750_CONTINUOUS_HIGH_RES_MODE 0x10

// 120ms 0.5lx resolution
#define BH1750_CONTINUOUS_HIGH_RES_MODE_2 0x11

// 16ms 4lx resolution
#define BH1750_CONTINUOUS_LOW_RES_MODE 0x13

// one time measurements powers down after measurement
// 120ms 1lx resolution
#define BH1750_ONE_TIME_HIGH_RES_MODE 0x20

// 120ms 0.5lx resolution
#define BH1750_ONE_TIME_HIGH_RES_MODE_2 0x21

// 16ms 4lx resolution
#define BH1750_ONE_TIME_LOW_RES_MODE 0x23

#define HIGH_RES_DELAY 120
#define LOW_RES_DELAY 16

bool bh1750_power_down();
bool bh1750_power_on();
bool bh1750_reset();

bool bh1750_set_mode(uint8_t mode);
uint16_t bh1750_read_light_level();

#endif // BH1750_H