Source code for sensirion_i2c_sgp4x.sgp41.commands

# -*- coding: utf-8 -*-
# (c) Copyright 2021 Sensirion AG, Switzerland

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#     THIS FILE IS AUTOMATICALLY GENERATED AND MUST NOT BE EDITED MANUALLY!
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# Generator:    sensirion-i2c-interface-generator 0.3.0
# Product:      SGP41
# Version:      0.1.0
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# flake8: noqa

from __future__ import absolute_import, division, print_function

import logging
from struct import pack, unpack

from sensirion_i2c_driver import SensirionI2cCommand, CrcCalculator

from sensirion_i2c_sgp4x.sgp41.response_types import Sgp41SrawVoc, Sgp41SrawNox

log = logging.getLogger(__name__)


[docs]class Sgp41I2cCmdBase(SensirionI2cCommand): """ SGP41 I²C base command. """
[docs] def __init__(self, command, tx_data, rx_length, read_delay, timeout, post_processing_time=0.0): """ Constructs a new SGP41 I²C command. :param int/None command: The command ID to be sent to the device. None means that no command will be sent, i.e. only ``tx_data`` (if not None) will be sent. No CRC is added to these bytes since the command ID usually already contains a CRC. :param bytes-like/list/None tx_data: Bytes to be extended with CRCs and then sent to the I²C device. None means that no write header will be sent at all (if ``command`` is None too). An empty list means to send the write header (even if ``command`` is None), but without data following it. :param int/None rx_length: Number of bytes to be read from the I²C device, including CRC bytes. None means that no read header is sent at all. Zero means to send the read header, but without reading any data. :param float read_delay: Delay (in Seconds) to be inserted between the end of the write operation and the beginning of the read operation. This is needed if the device needs some time to prepare the RX data, e.g. if it has to perform a measurement. Set to 0.0 to indicate that no delay is needed, i.e. the device does not need any processing time. :param float timeout: Timeout (in Seconds) to be used in case of clock stretching. If the device stretches the clock longer than this value, the transceive operation will be aborted with a timeout error. Set to 0.0 to indicate that the device will not stretch the clock for this command. :param float post_processing_time: Maximum time in seconds the device needs for post processing of this command until it is ready to receive the next command. For example after a device reset command, the device might need some time until it is ready again. Usually this is 0.0s, i.e. no post processing is needed. """ super(Sgp41I2cCmdBase, self).__init__( command=command, tx_data=tx_data, rx_length=rx_length, read_delay=read_delay, timeout=timeout, crc=CrcCalculator(8, 0x31, 0xFF, 0x00), command_bytes=2, post_processing_time=post_processing_time, )
[docs]class Sgp41I2cCmdExecuteConditioning(Sgp41I2cCmdBase): """ SGP41 Execute Conditioning I²C Command This command starts the conditioning, i.e., the VOC pixel will be operated at the same temperature as it is by calling the sgp41_measure_raw command while the NOx pixel will be operated at a different temperature for conditioning. This command returns only the measured raw signal of the VOC pixel SRAW_VOC as 2 bytes (+ 1 CRC byte). """
[docs] def __init__(self, default_rh, default_t): """ Constructor. :param int default_rh: Default conditions for relative humidty. :param int default_t: Default conditions for temperature. """ super(Sgp41I2cCmdExecuteConditioning, self).__init__( command=0x2612, tx_data=b"".join([pack(">H", default_rh), pack(">H", default_t)]), rx_length=3, read_delay=0.05, timeout=0, post_processing_time=0.0, )
[docs] def interpret_response(self, data): """ Validates the CRCs of the received data from the device and returns the interpreted data. :param bytes data: Received raw bytes from the read operation. :return: the raw signal SRAW_VOC in ticks which is proportional to the logarithm of the resistance of the sensing element. :rtype: :py:class:`~sensirion_i2c_sgp4x.sgp41.response_types.Sgp41SrawVoc` :raise ~sensirion_i2c_driver.errors.I2cChecksumError: If a received CRC was wrong. """ # check and remove CRCs checked_data = Sgp41I2cCmdBase.interpret_response(self, data) # convert raw received data into proper data types sraw_voc = int(unpack(">H", checked_data[0:2])[0]) # uint16 return Sgp41SrawVoc(sraw_voc)
[docs]class Sgp41I2cCmdMeasureRawSignals(Sgp41I2cCmdBase): """ SGP41 Measure Raw Signals I²C Command This command starts/continues the VOC+NOx measurement mode """
[docs] def __init__(self, relative_humidity, temperature): """ Constructor. :param int relative_humidity: Leaves humidity compensation disabled by sending the default value 0x8000 (50%RH) or enables humidity compensation when sending the relative humidity in ticks (ticks = %RH * 65535 / 100) :param int temperature: Leaves humidity compensation disabled by sending the default value 0x6666 (25 degC) or enables humidity compensation when sending the temperature in ticks (ticks = (degC + 45) * 65535 / 175) """ super(Sgp41I2cCmdMeasureRawSignals, self).__init__( command=0x2619, tx_data=b"".join([pack(">H", relative_humidity), pack(">H", temperature)]), rx_length=6, read_delay=0.05, timeout=0, post_processing_time=0.0, )
[docs] def interpret_response(self, data): """ Validates the CRCs of the received data from the device and returns the interpreted data. :param bytes data: Received raw bytes from the read operation. :return: - sraw_voc (:py:class:`~sensirion_i2c_sgp4x.sgp41.response_types.Sgp41SrawVoc`) - the raw signal SRAW_VOC in ticks which is proportional to the logarithm of the resistance of the sensing element. - sraw_nox (:py:class:`~sensirion_i2c_sgp4x.sgp41.response_types.Sgp41SrawNox`) - the raw signal SRAW_NOX in ticks which is proportional to the logarithm of the resistance of the sensing element. :rtype: tuple :raise ~sensirion_i2c_driver.errors.I2cChecksumError: If a received CRC was wrong. """ # check and remove CRCs checked_data = Sgp41I2cCmdBase.interpret_response(self, data) # convert raw received data into proper data types sraw_voc = int(unpack(">H", checked_data[0:2])[0]) # uint16 sraw_nox = int(unpack(">H", checked_data[2:4])[0]) # uint16 return Sgp41SrawVoc(sraw_voc), Sgp41SrawNox(sraw_nox)
[docs]class Sgp41I2cCmdExecuteSelfTest(Sgp41I2cCmdBase): """ SGP41 Execute Self Test I²C Command This command triggers the built-in self-test checking for integrity of both hotplate and MOX material and returns the result of this test as 2 bytes """
[docs] def __init__(self): """ Constructor. """ super(Sgp41I2cCmdExecuteSelfTest, self).__init__( command=0x280E, tx_data=None, rx_length=3, read_delay=0.32, timeout=0, post_processing_time=0.0, )
[docs] def interpret_response(self, data): """ Validates the CRCs of the received data from the device and returns the interpreted data. :param bytes data: Received raw bytes from the read operation. :return: 0xXX 0xYY: ignore most significant byte 0xXX. The four least significant bits of the least significant byte 0xYY provide information if the self-test has or has not passed for each individual pixel. All zero mean all tests passed successfully. Check the datasheet for more detailed information. :rtype: int :raise ~sensirion_i2c_driver.errors.I2cChecksumError: If a received CRC was wrong. """ # check and remove CRCs checked_data = Sgp41I2cCmdBase.interpret_response(self, data) # convert raw received data into proper data types test_result = int(unpack(">H", checked_data[0:2])[0]) # uint16 return test_result
[docs]class Sgp41I2cCmdTurnHeaterOff(Sgp41I2cCmdBase): """ SGP41 Turn Heater Off I²C Command This command turns the hotplate off and stops the measurement. Subsequently, the sensor enters the idle mode. """
[docs] def __init__(self): """ Constructor. """ super(Sgp41I2cCmdTurnHeaterOff, self).__init__( command=0x3615, tx_data=None, rx_length=None, read_delay=0.0, timeout=0, post_processing_time=0.001, )
[docs]class Sgp41I2cCmdGetSerialNumber(Sgp41I2cCmdBase): """ SGP41 Get Serial Number I²C Command This command provides the decimal serial number of the SGP41 chip by returning 3x2 bytes. """
[docs] def __init__(self): """ Constructor. """ super(Sgp41I2cCmdGetSerialNumber, self).__init__( command=0x3682, tx_data=None, rx_length=9, read_delay=0.001, timeout=0, post_processing_time=0.0, )
[docs] def interpret_response(self, data): """ Validates the CRCs of the received data from the device and returns the interpreted data. :param bytes data: Received raw bytes from the read operation. :return: 48-bit unique serial number :rtype: list(int) :raise ~sensirion_i2c_driver.errors.I2cChecksumError: If a received CRC was wrong. """ # check and remove CRCs checked_data = Sgp41I2cCmdBase.interpret_response(self, data) # convert raw received data into proper data types serial_number = [int(ii) for ii in unpack(">{}H".format(len(checked_data[0:6]) // 2), checked_data[0:6])] # list(uint16) return serial_number