<filename>adafruit_circuitpython_libs/adafruit-circuitpython-bundle-py-20210214/lib/adafruit_ltr390.py
# SPDX-FileCopyrightText: 2017 <NAME>, written for Adafruit Industries
# SPDX-FileCopyrightText: Copyright (c) 2020 <NAME> for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
`adafruit_ltr390`
================================================================================

Adafruit CircuitPython library for the LTR390


* Author(s): <NAME>

Implementation Notes
--------------------

**Hardware:**

* Adafruit LTR390 Breakout <https://www.adafruit.com/product/38XX>`_

**Software and Dependencies:**

* Adafruit CircuitPython firmware for the supported boards:
  https://github.com/adafruit/circuitpython/releases
* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
* Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
"""

from time import sleep
from struct import unpack_from, pack_into
from micropython import const
import adafruit_bus_device.i2c_device as i2c_device
from adafruit_register.i2c_struct import ROUnaryStruct, Struct
from adafruit_register.i2c_bits import RWBits
from adafruit_register.i2c_bit import RWBit, ROBit

__version__ = "1.0.2"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_LTR390.git"

_DEFAULT_I2C_ADDR = const(0x53)
_CTRL = const(0x00)  # Main control register
_MEAS_RATE = const(0x04)  # Resolution and data rate
_GAIN = const(0x05)  # ALS and UVS gain range
_PART_ID = const(0x06)  # Part id/revision register
_STATUS = const(0x07)  # Main status register
_ALSDATA = const(0x0D)  # ALS data lowest byte
_UVSDATA = const(0x10)  # UVS data lowest byte
_INT_CFG = const(0x19)  # Interrupt configuration
_INT_PST = const(0x1A)  # Interrupt persistance config
_THRESH_UP = const(0x21)  # Upper threshold, low byte
_THRESH_LOW = const(0x24)  # Lower threshold, low byte

ALS = 0
UV = 1


class UnalignedStruct(Struct):
    """Class for reading multi-byte data registers with a data length less than the full bitwidth
    of the registers. Most registers of this sort are left aligned to preserve the sign bit"""

    def __init__(self, register_address, struct_format, bitwidth, length):
        super().__init__(register_address, struct_format)
        self._width = bitwidth
        self._num_bytes = length

    def __get__(self, obj, objtype=None):
        # read bytes into buffer at correct alignment
        raw_value = unpack_from(self.format, self.buffer, offset=1)[0]

        with obj.i2c_device as i2c:
            i2c.write_then_readinto(
                self.buffer,
                self.buffer,
                out_start=0,
                out_end=1,
                in_start=2,  # right aligned
                # in_end=4 # right aligned
            )
        raw_value = unpack_from(self.format, self.buffer, offset=1)[0]
        return raw_value >> 8

    def __set__(self, obj, value):
        pack_into(self.format, self.buffer, 1, value)
        with obj.i2c_device as i2c:
            i2c.write(self.buffer)


class CV:
    """struct helper"""

    @classmethod
    def add_values(cls, value_tuples):
        """Add CV values to the class"""
        cls.string = {}
        cls.lsb = {}

        for value_tuple in value_tuples:
            name, value, string, lsb = value_tuple
            setattr(cls, name, value)
            cls.string[value] = string
            cls.lsb[value] = lsb

    @classmethod
    def is_valid(cls, value):
        """Validate that a given value is a member"""
        return value in cls.string


class Gain(CV):
    """Options for `gain`

    +---------------------------+----------------------------+
    | Gain                      | Raw Measurement Multiplier |
    +===========================+============================+
    | :py:const:`Gain.GAIN_1X`  | 1                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_3X`  | 3                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_6X`  | 6                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_9X`  | 9                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_18X` | 18                         |
    +---------------------------+----------------------------+

    """


Gain.add_values(
    (
        ("GAIN_1X", 0, "1X", None),
        ("GAIN_3X", 1, "3X", None),
        ("GAIN_6X", 2, "6X", None),
        ("GAIN_9X", 3, "9X", None),
        ("GAIN_18X", 4, "18X", None),
    )
)


class Resolution(CV):
    """Options for `resolution`

    +-----------------------------------------+-------------------------+
    | Resolution                              | Internal ADC Resolution |
    +=========================================+=========================+
    | :py:const:`Resolution.RESOLUTION_13BIT` | 13 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_16BIT` | 16 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_17BIT` | 17 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_18BIT` | 18 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_19BIT` | 19 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_20BIT` | 20 bits                 |
    +-----------------------------------------+-------------------------+

    """


Resolution.add_values(
    (
        ("RESOLUTION_20BIT", 0, "20 bits", None),
        ("RESOLUTION_19BIT", 1, "19 bits", None),
        ("RESOLUTION_18BIT", 2, "18 bits", None),
        ("RESOLUTION_17BIT", 3, "17 bits", None),
        ("RESOLUTION_16BIT", 4, "16 bits", None),
        ("RESOLUTION_13BIT", 5, "13 bits", None),
    )
)


class MeasurementDelay(CV):
    """Options for `measurement_delay`

    +-------------------------------------------+--------------------------------------+
    | MeasurementDelay                          | Time Between Measurement Cycles (ms) |
    +===========================================+======================================+
    | :py:const:`MeasurementDelay.DELAY_25MS`   | 25                                   |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_50MS`   | 50                                   |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_100MS`  | 100                                  |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_200MS`  | 200                                  |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_500MS`  | 500                                  |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_1000MS` | 1000                                 |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_2000MS` | 2000                                 |
    +-------------------------------------------+--------------------------------------+

    """


MeasurementDelay.add_values(
    (
        ("DELAY_25MS", 0, "25", None),
        ("DELAY_50MS", 1, "50", None),
        ("DELAY_100MS", 2, "100", None),
        ("DELAY_200MS", 3, "200", None),
        ("DELAY_500MS", 4, "500", None),
        ("DELAY_1000MS", 5, "1000", None),
        ("DELAY_2000MS", 6, "2000", None),
    )
)


class LTR390:  # pylint:disable=too-many-instance-attributes
    """Class to use the LTR390 Ambient Light and UV sensor"""

    _reset_bit = RWBit(_CTRL, 4)
    _enable_bit = RWBit(_CTRL, 1)
    _mode_bit = RWBit(_CTRL, 3)
    _int_enable_bit = RWBit(_INT_CFG, 2)

    _gain_bits = RWBits(3, _GAIN, 0)
    _resolution_bits = RWBits(3, _MEAS_RATE, 4)
    _measurement_delay_bits = RWBits(3, _MEAS_RATE, 0)
    _rate_bits = RWBits(3, _MEAS_RATE, 4)
    _int_src_bits = RWBits(2, _INT_CFG, 4)
    _int_persistance_bits = RWBits(4, _INT_PST, 4)

    _id_reg = ROUnaryStruct(_PART_ID, "<B")
    _uvs_data_reg = UnalignedStruct(_UVSDATA, "<I", 24, 3)
    _als_data_reg = UnalignedStruct(_ALSDATA, "<I", 24, 3)

    data_ready = ROBit(_STATUS, 3)
    """Ask the sensor if new data is available"""
    high_threshold = UnalignedStruct(_THRESH_UP, "<I", 24, 3)
    """When the measured value is more than the low_threshold, the sensor will raise an alert"""

    low_threshold = UnalignedStruct(_THRESH_LOW, "<I", 24, 3)
    """When the measured value is less than the low_threshold, the sensor will raise an alert"""

    threshold_passed = ROBit(_STATUS, 4)
    """The status of any configured alert. If True, a threshold has been passed.

    Once read, this property will be False until it is updated in the next measurement cycle"""

    def __init__(self, i2c, address=_DEFAULT_I2C_ADDR):
        self.i2c_device = i2c_device.I2CDevice(i2c, address)
        if self._id_reg != 0xB2:

            raise RuntimeError("Unable to find LTR390; check your wiring")

        self._mode_cache = None
        self.initialize()

    def initialize(self):
        """Reset the sensor to it's initial unconfigured state and configure it with sensible
        defaults so it can be used"""

        self._reset()
        self._enable_bit = True
        if not self._enable_bit:
            raise RuntimeError("Unable to enable sensor")
        self._mode = UV
        self.gain = Gain.GAIN_3X  # pylint:disable=no-member
        self.resolution = Resolution.RESOLUTION_16BIT  # pylint:disable=no-member

        # ltr.setThresholds(100, 1000);
        # self.low_threshold = 100
        # self.high_threshold = 1000
        # ltr.configInterrupt(true, LTR390_MODE_UVS);

    def _reset(self):
        try:
            self._reset_bit = True
        except OSError:
            # The write to the reset bit will fail because it seems to not ACK before it resets
            pass

        sleep(0.1)
        # check that reset is complete w/ the bit unset
        if self._reset_bit:
            raise RuntimeError("Unable to reset sensor")

    @property
    def _mode(self):
        return self._mode_bit

    @_mode.setter
    def _mode(self, value):
        if not value in [ALS, UV]:
            raise AttributeError("Mode must be ALS or UV")
        if self._mode_cache != value:
            self._mode_bit = value
            self._mode_cache = value
            sleep(0.030)

    # something is wrong here; I had to add a sleep to the loop to get both to update correctly
    @property
    def uvs(self):
        """The calculated UV value"""
        self._mode = UV
        while not self.data_ready:
            sleep(0.010)
        return self._uvs_data_reg

    @property
    def light(self):
        """The currently measured ambient light level"""
        self._mode = ALS
        while not self.data_ready:
            sleep(0.010)
        return self._als_data_reg

    @property
    def gain(self):
        """The amount of gain the raw measurements are multiplied by"""
        return self._gain_bits

    @gain.setter
    def gain(self, value):
        if not Gain.is_valid(value):
            raise AttributeError("gain must be a Gain")
        self._gain_bits = value

    @property
    def resolution(self):
        """Set the precision of the internal ADC used to read the light measurements"""
        return self._resolution_bits

    @resolution.setter
    def resolution(self, value):
        if not Resolution.is_valid(value):
            raise AttributeError("resolution must be a Resolution")
        self._resolution_bits = value

    def enable_alerts(self, enable, source, persistance):
        """The configuraiton of alerts raised by the sensor

        :param enable: Whether the interrupt output is enabled
        :param source: Whether to use the ALS or UVS data register to compare
        :param persistance: The number of consecutive out-of-range readings before
        """
        self._int_enable_bit = enable
        if not enable:
            return
        if source == ALS:
            self._int_src_bits = 1
        elif source == UV:
            self._int_src_bits = 3
        else:
            raise AttributeError("interrupt source must be UV or ALS")
        self._int_persistance_bits = persistance

    @property
    def measurement_delay(self):
        """The delay between measurements. This can be used to set the measurement rate which
        affects the sensors power usage."""
        return self._measurement_delay_bits

    @measurement_delay.setter
    def measurement_delay(self, value):
        if not MeasurementDelay.is_valid(value):
            raise AttributeError("measurement_delay must be a MeasurementDelay")
        self._measurement_delay_bits = value

<filename>adafruit_circuitpython_libs/adafruit-circuitpython-bundle-py-20210214/lib/adafruit_ltr390.py
# SPDX-FileCopyrightText: 2017 <NAME>, written for Adafruit Industries
# SPDX-FileCopyrightText: Copyright (c) 2020 <NAME> for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
`adafruit_ltr390`
================================================================================

Adafruit CircuitPython library for the LTR390


* Author(s): <NAME>

Implementation Notes
--------------------

**Hardware:**

* Adafruit LTR390 Breakout <https://www.adafruit.com/product/38XX>`_

**Software and Dependencies:**

* Adafruit CircuitPython firmware for the supported boards:
  https://github.com/adafruit/circuitpython/releases
* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
* Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
"""

from time import sleep
from struct import unpack_from, pack_into
from micropython import const
import adafruit_bus_device.i2c_device as i2c_device
from adafruit_register.i2c_struct import ROUnaryStruct, Struct
from adafruit_register.i2c_bits import RWBits
from adafruit_register.i2c_bit import RWBit, ROBit

__version__ = "1.0.2"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_LTR390.git"

_DEFAULT_I2C_ADDR = const(0x53)
_CTRL = const(0x00)  # Main control register
_MEAS_RATE = const(0x04)  # Resolution and data rate
_GAIN = const(0x05)  # ALS and UVS gain range
_PART_ID = const(0x06)  # Part id/revision register
_STATUS = const(0x07)  # Main status register
_ALSDATA = const(0x0D)  # ALS data lowest byte
_UVSDATA = const(0x10)  # UVS data lowest byte
_INT_CFG = const(0x19)  # Interrupt configuration
_INT_PST = const(0x1A)  # Interrupt persistance config
_THRESH_UP = const(0x21)  # Upper threshold, low byte
_THRESH_LOW = const(0x24)  # Lower threshold, low byte

ALS = 0
UV = 1


class UnalignedStruct(Struct):
    """Class for reading multi-byte data registers with a data length less than the full bitwidth
    of the registers. Most registers of this sort are left aligned to preserve the sign bit"""

    def __init__(self, register_address, struct_format, bitwidth, length):
        super().__init__(register_address, struct_format)
        self._width = bitwidth
        self._num_bytes = length

    def __get__(self, obj, objtype=None):
        # read bytes into buffer at correct alignment
        raw_value = unpack_from(self.format, self.buffer, offset=1)[0]

        with obj.i2c_device as i2c:
            i2c.write_then_readinto(
                self.buffer,
                self.buffer,
                out_start=0,
                out_end=1,
                in_start=2,  # right aligned
                # in_end=4 # right aligned
            )
        raw_value = unpack_from(self.format, self.buffer, offset=1)[0]
        return raw_value >> 8

    def __set__(self, obj, value):
        pack_into(self.format, self.buffer, 1, value)
        with obj.i2c_device as i2c:
            i2c.write(self.buffer)


class CV:
    """struct helper"""

    @classmethod
    def add_values(cls, value_tuples):
        """Add CV values to the class"""
        cls.string = {}
        cls.lsb = {}

        for value_tuple in value_tuples:
            name, value, string, lsb = value_tuple
            setattr(cls, name, value)
            cls.string[value] = string
            cls.lsb[value] = lsb

    @classmethod
    def is_valid(cls, value):
        """Validate that a given value is a member"""
        return value in cls.string


class Gain(CV):
    """Options for `gain`

    +---------------------------+----------------------------+
    | Gain                      | Raw Measurement Multiplier |
    +===========================+============================+
    | :py:const:`Gain.GAIN_1X`  | 1                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_3X`  | 3                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_6X`  | 6                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_9X`  | 9                          |
    +---------------------------+----------------------------+
    | :py:const:`Gain.GAIN_18X` | 18                         |
    +---------------------------+----------------------------+

    """


Gain.add_values(
    (
        ("GAIN_1X", 0, "1X", None),
        ("GAIN_3X", 1, "3X", None),
        ("GAIN_6X", 2, "6X", None),
        ("GAIN_9X", 3, "9X", None),
        ("GAIN_18X", 4, "18X", None),
    )
)


class Resolution(CV):
    """Options for `resolution`

    +-----------------------------------------+-------------------------+
    | Resolution                              | Internal ADC Resolution |
    +=========================================+=========================+
    | :py:const:`Resolution.RESOLUTION_13BIT` | 13 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_16BIT` | 16 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_17BIT` | 17 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_18BIT` | 18 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_19BIT` | 19 bits                 |
    +-----------------------------------------+-------------------------+
    | :py:const:`Resolution.RESOLUTION_20BIT` | 20 bits                 |
    +-----------------------------------------+-------------------------+

    """


Resolution.add_values(
    (
        ("RESOLUTION_20BIT", 0, "20 bits", None),
        ("RESOLUTION_19BIT", 1, "19 bits", None),
        ("RESOLUTION_18BIT", 2, "18 bits", None),
        ("RESOLUTION_17BIT", 3, "17 bits", None),
        ("RESOLUTION_16BIT", 4, "16 bits", None),
        ("RESOLUTION_13BIT", 5, "13 bits", None),
    )
)


class MeasurementDelay(CV):
    """Options for `measurement_delay`

    +-------------------------------------------+--------------------------------------+
    | MeasurementDelay                          | Time Between Measurement Cycles (ms) |
    +===========================================+======================================+
    | :py:const:`MeasurementDelay.DELAY_25MS`   | 25                                   |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_50MS`   | 50                                   |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_100MS`  | 100                                  |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_200MS`  | 200                                  |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_500MS`  | 500                                  |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_1000MS` | 1000                                 |
    +-------------------------------------------+--------------------------------------+
    | :py:const:`MeasurementDelay.DELAY_2000MS` | 2000                                 |
    +-------------------------------------------+--------------------------------------+

    """


MeasurementDelay.add_values(
    (
        ("DELAY_25MS", 0, "25", None),
        ("DELAY_50MS", 1, "50", None),
        ("DELAY_100MS", 2, "100", None),
        ("DELAY_200MS", 3, "200", None),
        ("DELAY_500MS", 4, "500", None),
        ("DELAY_1000MS", 5, "1000", None),
        ("DELAY_2000MS", 6, "2000", None),
    )
)


class LTR390:  # pylint:disable=too-many-instance-attributes
    """Class to use the LTR390 Ambient Light and UV sensor"""

    _reset_bit = RWBit(_CTRL, 4)
    _enable_bit = RWBit(_CTRL, 1)
    _mode_bit = RWBit(_CTRL, 3)
    _int_enable_bit = RWBit(_INT_CFG, 2)

    _gain_bits = RWBits(3, _GAIN, 0)
    _resolution_bits = RWBits(3, _MEAS_RATE, 4)
    _measurement_delay_bits = RWBits(3, _MEAS_RATE, 0)
    _rate_bits = RWBits(3, _MEAS_RATE, 4)
    _int_src_bits = RWBits(2, _INT_CFG, 4)
    _int_persistance_bits = RWBits(4, _INT_PST, 4)

    _id_reg = ROUnaryStruct(_PART_ID, "<B")
    _uvs_data_reg = UnalignedStruct(_UVSDATA, "<I", 24, 3)
    _als_data_reg = UnalignedStruct(_ALSDATA, "<I", 24, 3)

    data_ready = ROBit(_STATUS, 3)
    """Ask the sensor if new data is available"""
    high_threshold = UnalignedStruct(_THRESH_UP, "<I", 24, 3)
    """When the measured value is more than the low_threshold, the sensor will raise an alert"""

    low_threshold = UnalignedStruct(_THRESH_LOW, "<I", 24, 3)
    """When the measured value is less than the low_threshold, the sensor will raise an alert"""

    threshold_passed = ROBit(_STATUS, 4)
    """The status of any configured alert. If True, a threshold has been passed.

    Once read, this property will be False until it is updated in the next measurement cycle"""

    def __init__(self, i2c, address=_DEFAULT_I2C_ADDR):
        self.i2c_device = i2c_device.I2CDevice(i2c, address)
        if self._id_reg != 0xB2:

            raise RuntimeError("Unable to find LTR390; check your wiring")

        self._mode_cache = None
        self.initialize()

    def initialize(self):
        """Reset the sensor to it's initial unconfigured state and configure it with sensible
        defaults so it can be used"""

        self._reset()
        self._enable_bit = True
        if not self._enable_bit:
            raise RuntimeError("Unable to enable sensor")
        self._mode = UV
        self.gain = Gain.GAIN_3X  # pylint:disable=no-member
        self.resolution = Resolution.RESOLUTION_16BIT  # pylint:disable=no-member

        # ltr.setThresholds(100, 1000);
        # self.low_threshold = 100
        # self.high_threshold = 1000
        # ltr.configInterrupt(true, LTR390_MODE_UVS);

    def _reset(self):
        try:
            self._reset_bit = True
        except OSError:
            # The write to the reset bit will fail because it seems to not ACK before it resets
            pass

        sleep(0.1)
        # check that reset is complete w/ the bit unset
        if self._reset_bit:
            raise RuntimeError("Unable to reset sensor")

    @property
    def _mode(self):
        return self._mode_bit

    @_mode.setter
    def _mode(self, value):
        if not value in [ALS, UV]:
            raise AttributeError("Mode must be ALS or UV")
        if self._mode_cache != value:
            self._mode_bit = value
            self._mode_cache = value
            sleep(0.030)

    # something is wrong here; I had to add a sleep to the loop to get both to update correctly
    @property
    def uvs(self):
        """The calculated UV value"""
        self._mode = UV
        while not self.data_ready:
            sleep(0.010)
        return self._uvs_data_reg

    @property
    def light(self):
        """The currently measured ambient light level"""
        self._mode = ALS
        while not self.data_ready:
            sleep(0.010)
        return self._als_data_reg

    @property
    def gain(self):
        """The amount of gain the raw measurements are multiplied by"""
        return self._gain_bits

    @gain.setter
    def gain(self, value):
        if not Gain.is_valid(value):
            raise AttributeError("gain must be a Gain")
        self._gain_bits = value

    @property
    def resolution(self):
        """Set the precision of the internal ADC used to read the light measurements"""
        return self._resolution_bits

    @resolution.setter
    def resolution(self, value):
        if not Resolution.is_valid(value):
            raise AttributeError("resolution must be a Resolution")
        self._resolution_bits = value

    def enable_alerts(self, enable, source, persistance):
        """The configuraiton of alerts raised by the sensor

        :param enable: Whether the interrupt output is enabled
        :param source: Whether to use the ALS or UVS data register to compare
        :param persistance: The number of consecutive out-of-range readings before
        """
        self._int_enable_bit = enable
        if not enable:
            return
        if source == ALS:
            self._int_src_bits = 1
        elif source == UV:
            self._int_src_bits = 3
        else:
            raise AttributeError("interrupt source must be UV or ALS")
        self._int_persistance_bits = persistance

    @property
    def measurement_delay(self):
        """The delay between measurements. This can be used to set the measurement rate which
        affects the sensors power usage."""
        return self._measurement_delay_bits

    @measurement_delay.setter
    def measurement_delay(self, value):
        if not MeasurementDelay.is_valid(value):
            raise AttributeError("measurement_delay must be a MeasurementDelay")
        self._measurement_delay_bits = value

# SPDX-FileCopyrightText: 2017 <NAME>, written for Adafruit Industries # SPDX-FileCopyrightText: Copyright (c) 2020 <NAME> for Adafruit Industries # # SPDX-License-Identifier: MIT `adafruit_ltr390` ================================================================================  Adafruit CircuitPython library for the LTR390   * Author(s): <NAME>  Implementation Notes --------------------  **Hardware:**  * Adafruit LTR390 Breakout <https://www.adafruit.com/product/38XX>`_  **Software and Dependencies:**  * Adafruit CircuitPython firmware for the supported boards:   https://github.com/adafruit/circuitpython/releases * Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice * Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register # Main control register # Resolution and data rate # ALS and UVS gain range # Part id/revision register # Main status register # ALS data lowest byte # UVS data lowest byte # Interrupt configuration # Interrupt persistance config # Upper threshold, low byte # Lower threshold, low byte Class for reading multi-byte data registers with a data length less than the full bitwidth     of the registers. Most registers of this sort are left aligned to preserve the sign bit # read bytes into buffer at correct alignment # right aligned # in_end=4 # right aligned struct helper Add CV values to the class Validate that a given value is a member Options for `gain`      +---------------------------+----------------------------+     | Gain                      | Raw Measurement Multiplier |     +===========================+============================+     | :py:const:`Gain.GAIN_1X`  | 1                          |     +---------------------------+----------------------------+     | :py:const:`Gain.GAIN_3X`  | 3                          |     +---------------------------+----------------------------+     | :py:const:`Gain.GAIN_6X`  | 6                          |     +---------------------------+----------------------------+     | :py:const:`Gain.GAIN_9X`  | 9                          |     +---------------------------+----------------------------+     | :py:const:`Gain.GAIN_18X` | 18                         |     +---------------------------+----------------------------+ Options for `resolution`      +-----------------------------------------+-------------------------+     | Resolution                              | Internal ADC Resolution |     +=========================================+=========================+     | :py:const:`Resolution.RESOLUTION_13BIT` | 13 bits                 |     +-----------------------------------------+-------------------------+     | :py:const:`Resolution.RESOLUTION_16BIT` | 16 bits                 |     +-----------------------------------------+-------------------------+     | :py:const:`Resolution.RESOLUTION_17BIT` | 17 bits                 |     +-----------------------------------------+-------------------------+     | :py:const:`Resolution.RESOLUTION_18BIT` | 18 bits                 |     +-----------------------------------------+-------------------------+     | :py:const:`Resolution.RESOLUTION_19BIT` | 19 bits                 |     +-----------------------------------------+-------------------------+     | :py:const:`Resolution.RESOLUTION_20BIT` | 20 bits                 |     +-----------------------------------------+-------------------------+ Options for `measurement_delay`      +-------------------------------------------+--------------------------------------+     | MeasurementDelay                          | Time Between Measurement Cycles (ms) |     +===========================================+======================================+     | :py:const:`MeasurementDelay.DELAY_25MS`   | 25                                   |     +-------------------------------------------+--------------------------------------+     | :py:const:`MeasurementDelay.DELAY_50MS`   | 50                                   |     +-------------------------------------------+--------------------------------------+     | :py:const:`MeasurementDelay.DELAY_100MS`  | 100                                  |     +-------------------------------------------+--------------------------------------+     | :py:const:`MeasurementDelay.DELAY_200MS`  | 200                                  |     +-------------------------------------------+--------------------------------------+     | :py:const:`MeasurementDelay.DELAY_500MS`  | 500                                  |     +-------------------------------------------+--------------------------------------+     | :py:const:`MeasurementDelay.DELAY_1000MS` | 1000                                 |     +-------------------------------------------+--------------------------------------+     | :py:const:`MeasurementDelay.DELAY_2000MS` | 2000                                 |     +-------------------------------------------+--------------------------------------+ # pylint:disable=too-many-instance-attributes Class to use the LTR390 Ambient Light and UV sensor Ask the sensor if new data is available When the measured value is more than the low_threshold, the sensor will raise an alert When the measured value is less than the low_threshold, the sensor will raise an alert The status of any configured alert. If True, a threshold has been passed.      Once read, this property will be False until it is updated in the next measurement cycle Reset the sensor to it's initial unconfigured state and configure it with sensible         defaults so it can be used # pylint:disable=no-member # pylint:disable=no-member # ltr.setThresholds(100, 1000); # self.low_threshold = 100 # self.high_threshold = 1000 # ltr.configInterrupt(true, LTR390_MODE_UVS); # The write to the reset bit will fail because it seems to not ACK before it resets # check that reset is complete w/ the bit unset # something is wrong here; I had to add a sleep to the loop to get both to update correctly The calculated UV value The currently measured ambient light level The amount of gain the raw measurements are multiplied by Set the precision of the internal ADC used to read the light measurements The configuraiton of alerts raised by the sensor          :param enable: Whether the interrupt output is enabled         :param source: Whether to use the ALS or UVS data register to compare         :param persistance: The number of consecutive out-of-range readings before The delay between measurements. This can be used to set the measurement rate which         affects the sensors power usage.