halvfigur/ltr303

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# LTR303 driver for ESP32
A driver for the LITE-ON LTR-303ALS-01 digital light sensor.
[Datasheet](https://optoelectronics.liteon.com/upload/download/DS86-2013-0004/LTR-303ALS-01_DS_V1.pdf)

## Example application
```c
#include "esp_check.h"

#include <freertos/FreeRTOS.h>

#include "ltr303.h"

static const char *TAG = "app_main";

void app_main(void) {
  i2c_master_bus_config_t i2c_mst_config = {
      .clk_source = I2C_CLK_SRC_DEFAULT,
      .i2c_port = I2C_NUM_0,
      .scl_io_num = CONFIG_LTR303_I2C_SCL,
      .sda_io_num = CONFIG_LTR303_I2C_SDA,
      .glitch_ignore_cnt = 7,
      .flags.enable_internal_pullup = false,
  };

  i2c_master_bus_handle_t i2c_hdl;
  ESP_ERROR_CHECK(i2c_new_master_bus(&i2c_mst_config, &i2c_hdl));
  ESP_ERROR_CHECK(i2c_master_bus_reset(i2c_hdl));

  ltr303_handle_t *hdl;

  ESP_ERROR_CHECK(ltr303_new(&hdl, i2c_hdl));

  // Wait fo device to power up
  vTaskDelay(pdMS_TO_TICKS(200));

  als_contr_gain_t gain = ALS_CONTR_GAIN_1X;
  // Activate device
  ESP_ERROR_CHECK(ltr303_als_contr_set(hdl, ALS_CONTR_GAIN_1X, ALS_SW_RESET_OFF,
                                       ALS_ACTIVE, 10));
  vTaskDelay(pdMS_TO_TICKS(10));

  // Set integration time and measurement rate
  als_int_time_t time = ALS_INT_TIME_100;
  als_meas_rate_t rate = ASL_MEAS_RATE_500;

  ESP_ERROR_CHECK(ltr303_als_meas_rate_set(hdl, time, rate, 10));

  while (1) {
    uint8_t status;
    ESP_ERROR_CHECK(ltr303_als_status_get(hdl, &status, 10));

    if (als_status_data_valid(status) == ALS_STATUS_DATA_INVALID) {
      vTaskDelay(pdMS_TO_TICKS(10));
      continue;
    }

    uint16_t ch0;
    uint16_t ch1;

    ESP_ERROR_CHECK(ltr303_als_data_get(hdl, &ch0, &ch1, 10));

    float lux = ltr303_als_to_lux(gain, time, 1.0, ch0, ch1);
    ESP_LOGI(TAG, "CH0 %d, CH1: %d, LUX: %.2f", ch0, ch1, lux);

    vTaskDelay(pdMS_TO_TICKS(500));
  };
}
```