ccs811LIBRARY.py

"""
EDITED by Joy-IT
"""

"""
CCS811 Air Quality Sensor Example Code
Author: Sasa Saftic (sasa@infincube.si)
infincube d.o.o.
Date: June 8th, 2017
License: This code is public domain

Based on Sparkfuns Example code written by Nathan Seidle

Read the TVOC and CO2 values from the SparkFun CSS811 breakout board

A new sensor requires at 48-burn in. Once burned in a sensor requires
20 minutes of run in before readings are considered good.

The MIT License (MIT)

Copyright (c) 2016 SparkFun Electronics

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in the
Software without restriction, including without limitation the rights to use, copy,
modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
and to permit persons to whom the Software is furnished to do so, subject to the
following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""


import pigpio
import time
CCS811_ADDR = 0x5A  # default I2C Address

CSS811_STATUS = 0x00
CSS811_MEAS_MODE = 0x01
CSS811_ALG_RESULT_DATA = 0x02
CSS811_RAW_DATA = 0x03
CSS811_ENV_DATA = 0x05
CSS811_NTC = 0x06
CSS811_THRESHOLDS = 0x10
CSS811_BASELINE = 0x11
CSS811_HW_ID = 0x20
CSS811_HW_VERSION = 0x21
CSS811_FW_BOOT_VERSION = 0x23
CSS811_FW_APP_VERSION = 0x24
CSS811_ERROR_ID = 0xE0
CSS811_APP_START = 0xF4
CSS811_SW_RESET = 0xFF


class CCS811:
    def __init__(self):
        self.pi = pigpio.pi()
        self.device = self.pi.i2c_open(1, CCS811_ADDR)
        self.tVOC = 0
        self.CO2 = 0

    def print_error(self):
        error = self.pi.i2c_read_byte_data(self.device, CSS811_ERROR_ID)
        message = 'Error: '

        if error & 1 << 5:
            message += 'HeaterSupply '
        elif error & 1 << 4:
            message += 'HeaterFault '
        elif error & 1 << 3:
            message += 'MaxResistance '
        elif error & 1 << 2:
            message += 'MeasModeInvalid '
        elif error & 1 << 1:
            message += 'ReadRegInvalid '
        elif error & 1 << 0:
            message += 'MsgInvalid '

        print(message)

    def check_for_error(self):
        value = self.pi.i2c_read_byte_data(self.device, CSS811_STATUS)
        return value & 1 << 0

    def app_valid(self):
        value = self.pi.i2c_read_byte_data(self.device, CSS811_STATUS)
        return value & 1 << 4

    def set_drive_mode(self, mode):
        if mode > 4:
            mode = 4

        setting = self.pi.i2c_read_byte_data(self.device, CSS811_MEAS_MODE)
        setting &= ~(0b00000111 << 4)
        setting |= (mode << 4)
        self.pi.i2c_write_byte_data(self.device, CSS811_MEAS_MODE, setting)

    def configure_ccs811(self):
        hardware_id = self.pi.i2c_read_byte_data(self.device, CSS811_HW_ID)

        if hardware_id != 0x81:
            raise ValueError('CCS811 not found. Please check wiring.')

        if self.check_for_error():
            self.print_error()
            raise ValueError('Error at Startup.')

        if not self.app_valid():
            raise ValueError('Error: App not valid.')

        self.pi.i2c_write_byte(self.device, CSS811_APP_START)

        if self.check_for_error():
            self.print_error()
            raise ValueError('Error at AppStart.')

    def get_base_line(self):
        a, b = self.pi.i2c_read_i2c_block_data(self.device, CSS811_BASELINE, 2)
        baselineMSB = b[0]
        baselineLSB = b[1]
        baseline = (baselineMSB << 8) | baselineLSB
        return baseline

    def data_available(self):
        value = self.pi.i2c_read_byte_data(self.device, CSS811_STATUS)
        return value & 1 << 3

    def read_logorithm_results(self):
        b, d = self.pi.i2c_read_i2c_block_data(
            self.device, CSS811_ALG_RESULT_DATA, 4)

        co2MSB = d[0]
        co2LSB = d[1]
        tvocMSB = d[2]
        tvocLSB = d[3]

        self.CO2 = (co2MSB << 8) | co2LSB
        self.tVOC = (tvocMSB << 8) | tvocLSB