576 lines
18 KiB
C++
576 lines
18 KiB
C++
/*!
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* @file Adafruit_BME280.cpp
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*
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* @mainpage Adafruit BME280 humidity, temperature & pressure sensor
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*
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* @section intro_sec Introduction
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*
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* Driver for the BME280 humidity, temperature & pressure sensor
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*
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* These sensors use I2C or SPI to communicate, 2 or 4 pins are required
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* to interface.
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*
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* Designed specifically to work with the Adafruit BME280 Breakout
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* ----> http://www.adafruit.com/products/2652
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*
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit and open-source hardware by purchasing
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* products from Adafruit!
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*
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* @section author Author
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*
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* Written by Kevin "KTOWN" Townsend for Adafruit Industries.
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*
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* @section license License
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*
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* BSD license, all text here must be included in any redistribution.
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* See the LICENSE file for details.
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*
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*/
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#include "Adafruit_BME280.h"
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#include "Arduino.h"
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#include <SPI.h>
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#include <Wire.h>
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/*!
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* @brief class constructor
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*/
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Adafruit_BME280::Adafruit_BME280() : _cs(-1), _mosi(-1), _miso(-1), _sck(-1) {}
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/*!
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* @brief class constructor if using hardware SPI
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* @param cspin the chip select pin to use
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* @param *theSPI
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* optional SPI object
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*/
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Adafruit_BME280::Adafruit_BME280(int8_t cspin, SPIClass *theSPI) {
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_cs = cspin;
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_mosi = _miso = _sck = -1;
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_spi = theSPI;
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}
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/*!
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* @brief class constructor if using software SPI
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* @param cspin the chip select pin to use
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* @param mosipin the MOSI pin to use
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* @param misopin the MISO pin to use
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* @param sckpin the SCK pin to use
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*/
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Adafruit_BME280::Adafruit_BME280(int8_t cspin, int8_t mosipin, int8_t misopin,
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int8_t sckpin)
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: _cs(cspin), _mosi(mosipin), _miso(misopin), _sck(sckpin) {}
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/*!
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* @brief Initialise sensor with given parameters / settings
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* @param theWire the I2C object to use
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* @returns true on success, false otherwise
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*/
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bool Adafruit_BME280::begin(TwoWire *theWire) {
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_wire = theWire;
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_i2caddr = BME280_ADDRESS;
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return init();
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}
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/*!
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* @brief Initialise sensor with given parameters / settings
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* @param addr the I2C address the device can be found on
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* @returns true on success, false otherwise
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*/
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bool Adafruit_BME280::begin(uint8_t addr) {
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_i2caddr = addr;
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_wire = &Wire;
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return init();
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}
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/*!
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* @brief Initialise sensor with given parameters / settings
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* @param addr the I2C address the device can be found on
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* @param theWire the I2C object to use
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* @returns true on success, false otherwise
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*/
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bool Adafruit_BME280::begin(uint8_t addr, TwoWire *theWire) {
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_i2caddr = addr;
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_wire = theWire;
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return init();
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}
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/*!
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* @brief Initialise sensor with given parameters / settings
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* @returns true on success, false otherwise
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*/
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bool Adafruit_BME280::begin(void) {
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bool status = false;
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_i2caddr = BME280_ADDRESS;
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_wire = &Wire;
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status = init();
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if (!status) {
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_i2caddr = BME280_ADDRESS_ALTERNATE;
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status = init();
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}
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return status;
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}
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/*!
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* @brief Initialise sensor with given parameters / settings
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* @returns true on success, false otherwise
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*/
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bool Adafruit_BME280::init() {
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// init I2C or SPI sensor interface
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if (_cs == -1) {
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// I2C
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_wire->begin();
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} else {
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digitalWrite(_cs, HIGH);
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pinMode(_cs, OUTPUT);
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if (_sck == -1) {
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// hardware SPI
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_spi->begin();
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} else {
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// software SPI
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pinMode(_sck, OUTPUT);
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pinMode(_mosi, OUTPUT);
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pinMode(_miso, INPUT);
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}
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}
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// check if sensor, i.e. the chip ID is correct
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_sensorID = read8(BME280_REGISTER_CHIPID);
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if (_sensorID != 0x60)
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return false;
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// reset the device using soft-reset
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// this makes sure the IIR is off, etc.
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write8(BME280_REGISTER_SOFTRESET, 0xB6);
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// wait for chip to wake up.
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delay(300);
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// if chip is still reading calibration, delay
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while (isReadingCalibration())
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delay(100);
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readCoefficients(); // read trimming parameters, see DS 4.2.2
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setSampling(); // use defaults
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delay(100);
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return true;
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}
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/*!
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* @brief setup sensor with given parameters / settings
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*
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* This is simply a overload to the normal begin()-function, so SPI users
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* don't get confused about the library requiring an address.
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* @param mode the power mode to use for the sensor
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* @param tempSampling the temp samping rate to use
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* @param pressSampling the pressure sampling rate to use
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* @param humSampling the humidity sampling rate to use
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* @param filter the filter mode to use
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* @param duration the standby duration to use
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*/
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void Adafruit_BME280::setSampling(sensor_mode mode,
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sensor_sampling tempSampling,
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sensor_sampling pressSampling,
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sensor_sampling humSampling,
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sensor_filter filter,
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standby_duration duration) {
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_measReg.mode = mode;
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_measReg.osrs_t = tempSampling;
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_measReg.osrs_p = pressSampling;
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_humReg.osrs_h = humSampling;
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_configReg.filter = filter;
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_configReg.t_sb = duration;
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// making sure sensor is in sleep mode before setting configuration
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// as it otherwise may be ignored
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write8(BME280_REGISTER_CONTROL, MODE_SLEEP);
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// you must make sure to also set REGISTER_CONTROL after setting the
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// CONTROLHUMID register, otherwise the values won't be applied (see
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// DS 5.4.3)
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write8(BME280_REGISTER_CONTROLHUMID, _humReg.get());
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write8(BME280_REGISTER_CONFIG, _configReg.get());
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write8(BME280_REGISTER_CONTROL, _measReg.get());
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}
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/*!
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* @brief Encapsulate hardware and software SPI transfer into one
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* function
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* @param x the data byte to transfer
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* @returns the data byte read from the device
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*/
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uint8_t Adafruit_BME280::spixfer(uint8_t x) {
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// hardware SPI
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if (_sck == -1)
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return _spi->transfer(x);
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// software SPI
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uint8_t reply = 0;
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for (int i = 7; i >= 0; i--) {
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reply <<= 1;
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digitalWrite(_sck, LOW);
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digitalWrite(_mosi, x & (1 << i));
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digitalWrite(_sck, HIGH);
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if (digitalRead(_miso))
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reply |= 1;
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}
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return reply;
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}
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/*!
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* @brief Writes an 8 bit value over I2C or SPI
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* @param reg the register address to write to
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* @param value the value to write to the register
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*/
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void Adafruit_BME280::write8(byte reg, byte value) {
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if (_cs == -1) {
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_wire->beginTransmission((uint8_t)_i2caddr);
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_wire->write((uint8_t)reg);
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_wire->write((uint8_t)value);
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_wire->endTransmission();
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} else {
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if (_sck == -1)
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_spi->beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
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digitalWrite(_cs, LOW);
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spixfer(reg & ~0x80); // write, bit 7 low
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spixfer(value);
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digitalWrite(_cs, HIGH);
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if (_sck == -1)
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_spi->endTransaction(); // release the SPI bus
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}
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}
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/*!
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* @brief Reads an 8 bit value over I2C or SPI
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* @param reg the register address to read from
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* @returns the data byte read from the device
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*/
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uint8_t Adafruit_BME280::read8(byte reg) {
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uint8_t value;
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if (_cs == -1) {
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_wire->beginTransmission((uint8_t)_i2caddr);
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_wire->write((uint8_t)reg);
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_wire->endTransmission();
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_wire->requestFrom((uint8_t)_i2caddr, (byte)1);
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value = _wire->read();
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} else {
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if (_sck == -1)
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_spi->beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
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digitalWrite(_cs, LOW);
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spixfer(reg | 0x80); // read, bit 7 high
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value = spixfer(0);
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digitalWrite(_cs, HIGH);
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if (_sck == -1)
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_spi->endTransaction(); // release the SPI bus
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}
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return value;
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}
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/*!
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* @brief Reads a 16 bit value over I2C or SPI
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* @param reg the register address to read from
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* @returns the 16 bit data value read from the device
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*/
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uint16_t Adafruit_BME280::read16(byte reg) {
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uint16_t value;
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if (_cs == -1) {
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_wire->beginTransmission((uint8_t)_i2caddr);
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_wire->write((uint8_t)reg);
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_wire->endTransmission();
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_wire->requestFrom((uint8_t)_i2caddr, (byte)2);
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value = (_wire->read() << 8) | _wire->read();
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} else {
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if (_sck == -1)
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_spi->beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
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digitalWrite(_cs, LOW);
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spixfer(reg | 0x80); // read, bit 7 high
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value = (spixfer(0) << 8) | spixfer(0);
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digitalWrite(_cs, HIGH);
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if (_sck == -1)
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_spi->endTransaction(); // release the SPI bus
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}
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return value;
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}
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/*!
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* @brief Reads a signed 16 bit little endian value over I2C or SPI
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* @param reg the register address to read from
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* @returns the 16 bit data value read from the device
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*/
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uint16_t Adafruit_BME280::read16_LE(byte reg) {
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uint16_t temp = read16(reg);
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return (temp >> 8) | (temp << 8);
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}
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/*!
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* @brief Reads a signed 16 bit value over I2C or SPI
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* @param reg the register address to read from
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* @returns the 16 bit data value read from the device
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*/
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int16_t Adafruit_BME280::readS16(byte reg) { return (int16_t)read16(reg); }
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/*!
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* @brief Reads a signed little endian 16 bit value over I2C or SPI
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* @param reg the register address to read from
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* @returns the 16 bit data value read from the device
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*/
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int16_t Adafruit_BME280::readS16_LE(byte reg) {
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return (int16_t)read16_LE(reg);
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}
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/*!
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* @brief Reads a 24 bit value over I2C
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* @param reg the register address to read from
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* @returns the 24 bit data value read from the device
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*/
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uint32_t Adafruit_BME280::read24(byte reg) {
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uint32_t value;
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if (_cs == -1) {
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_wire->beginTransmission((uint8_t)_i2caddr);
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_wire->write((uint8_t)reg);
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_wire->endTransmission();
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_wire->requestFrom((uint8_t)_i2caddr, (byte)3);
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value = _wire->read();
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value <<= 8;
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value |= _wire->read();
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value <<= 8;
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value |= _wire->read();
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} else {
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if (_sck == -1)
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_spi->beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
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digitalWrite(_cs, LOW);
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spixfer(reg | 0x80); // read, bit 7 high
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value = spixfer(0);
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value <<= 8;
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value |= spixfer(0);
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value <<= 8;
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value |= spixfer(0);
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digitalWrite(_cs, HIGH);
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if (_sck == -1)
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_spi->endTransaction(); // release the SPI bus
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}
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return value;
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}
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/*!
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* @brief Take a new measurement (only possible in forced mode)
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*/
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void Adafruit_BME280::takeForcedMeasurement() {
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// If we are in forced mode, the BME sensor goes back to sleep after each
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// measurement and we need to set it to forced mode once at this point, so
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// it will take the next measurement and then return to sleep again.
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// In normal mode simply does new measurements periodically.
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if (_measReg.mode == MODE_FORCED) {
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// set to forced mode, i.e. "take next measurement"
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write8(BME280_REGISTER_CONTROL, _measReg.get());
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// wait until measurement has been completed, otherwise we would read
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// the values from the last measurement
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while (read8(BME280_REGISTER_STATUS) & 0x08)
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delay(1);
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}
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}
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/*!
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* @brief Reads the factory-set coefficients
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*/
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void Adafruit_BME280::readCoefficients(void) {
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_bme280_calib.dig_T1 = read16_LE(BME280_REGISTER_DIG_T1);
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_bme280_calib.dig_T2 = readS16_LE(BME280_REGISTER_DIG_T2);
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_bme280_calib.dig_T3 = readS16_LE(BME280_REGISTER_DIG_T3);
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Serial.printf("Temp Coeffs: %04X %04X %04X\r\n", _bme280_calib.dig_T1, _bme280_calib.dig_T2, _bme280_calib.dig_T3);
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_bme280_calib.dig_P1 = read16_LE(BME280_REGISTER_DIG_P1);
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_bme280_calib.dig_P2 = readS16_LE(BME280_REGISTER_DIG_P2);
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_bme280_calib.dig_P3 = readS16_LE(BME280_REGISTER_DIG_P3);
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_bme280_calib.dig_P4 = readS16_LE(BME280_REGISTER_DIG_P4);
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_bme280_calib.dig_P5 = readS16_LE(BME280_REGISTER_DIG_P5);
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_bme280_calib.dig_P6 = readS16_LE(BME280_REGISTER_DIG_P6);
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_bme280_calib.dig_P7 = readS16_LE(BME280_REGISTER_DIG_P7);
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_bme280_calib.dig_P8 = readS16_LE(BME280_REGISTER_DIG_P8);
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_bme280_calib.dig_P9 = readS16_LE(BME280_REGISTER_DIG_P9);
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_bme280_calib.dig_H1 = read8(BME280_REGISTER_DIG_H1);
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_bme280_calib.dig_H2 = readS16_LE(BME280_REGISTER_DIG_H2);
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_bme280_calib.dig_H3 = read8(BME280_REGISTER_DIG_H3);
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_bme280_calib.dig_H4 = (read8(BME280_REGISTER_DIG_H4) << 4) |
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(read8(BME280_REGISTER_DIG_H4 + 1) & 0xF);
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_bme280_calib.dig_H5 = (read8(BME280_REGISTER_DIG_H5 + 1) << 4) |
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(read8(BME280_REGISTER_DIG_H5) >> 4);
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_bme280_calib.dig_H6 = (int8_t)read8(BME280_REGISTER_DIG_H6);
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}
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/*!
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* @brief return true if chip is busy reading cal data
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* @returns true if reading calibration, false otherwise
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*/
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bool Adafruit_BME280::isReadingCalibration(void) {
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uint8_t const rStatus = read8(BME280_REGISTER_STATUS);
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return (rStatus & (1 << 0)) != 0;
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}
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/*!
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* @brief Returns the temperature from the sensor
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* @returns the temperature read from the device
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*/
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float Adafruit_BME280::readTemperature(void) {
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// double var1, var2;
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int32_t var1, var2;
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int32_t adc_T = read24(BME280_REGISTER_TEMPDATA);
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if (adc_T == 0x800000) // value in case temp measurement was disabled
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return NAN;
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adc_T >>= 4;
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// first reads 2C high @24
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//second is based upon this python code https://github.com/loboris/MicroPython_ESP32_psRAM_LoBo/blob/master/MicroPython_BUILD/components/micropython/esp32/modules_examples/bme280.py
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// var1 = ((((adc_T >> 3) - ((int32_t)_bme280_calib.dig_T1 << 1))) * ((int32_t)_bme280_calib.dig_T2)) >> 11;
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var1 = ((adc_T >> 3) - ((int32_t)_bme280_calib.dig_T1 << 1)) * ((int32_t)_bme280_calib.dig_T2 >> 11);
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var2 = (((((adc_T >> 4) - ((int32_t)_bme280_calib.dig_T1)) *
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((adc_T >> 4) - ((int32_t)_bme280_calib.dig_T1))) >> 12) * ((int32_t)_bme280_calib.dig_T3)) >> 14;
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/*var1 = ((double)adc_T) / 16384.0 - ((double)_bme280_calib.dig_T1) / 1024.0;
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var1 = var1 * ((double)_bme280_calib.dig_T2);
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var2 = (((double)adc_T) / 131072.0 - ((double)_bme280_calib.dig_T1) / 8192.0);
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var2 = (var2 * var2) * ((double)_bme280_calib.dig_T3);
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*/
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t_fine = (int32_t)(var1 + var2);
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// float T = (var1 + var2) / 5120.0;
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// return T;
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t_fine = var1 + var2;
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float T = (t_fine * 5 + 128) >> 8;
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return T / 100;
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}
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/*!
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* @brief Returns the pressure from the sensor
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* @returns the pressure value (in Pascal) read from the device
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*/
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float Adafruit_BME280::readPressure(void) {
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int64_t var1, var2, p;
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readTemperature(); // must be done first to get t_fine
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int32_t adc_P = read24(BME280_REGISTER_PRESSUREDATA);
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if (adc_P == 0x800000) // value in case pressure measurement was disabled
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return NAN;
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adc_P >>= 4;
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var1 = ((int64_t)t_fine) - 128000;
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|
var2 = var1 * var1 * (int64_t)_bme280_calib.dig_P6;
|
|
var2 = var2 + ((var1 * (int64_t)_bme280_calib.dig_P5) << 17);
|
|
var2 = var2 + (((int64_t)_bme280_calib.dig_P4) << 35);
|
|
var1 = ((var1 * var1 * (int64_t)_bme280_calib.dig_P3) >> 8) +
|
|
((var1 * (int64_t)_bme280_calib.dig_P2) << 12);
|
|
var1 =
|
|
(((((int64_t)1) << 47) + var1)) * ((int64_t)_bme280_calib.dig_P1) >> 33;
|
|
|
|
if (var1 == 0) {
|
|
return 0; // avoid exception caused by division by zero
|
|
}
|
|
p = 1048576 - adc_P;
|
|
p = (((p << 31) - var2) * 3125) / var1;
|
|
var1 = (((int64_t)_bme280_calib.dig_P9) * (p >> 13) * (p >> 13)) >> 25;
|
|
var2 = (((int64_t)_bme280_calib.dig_P8) * p) >> 19;
|
|
|
|
p = ((p + var1 + var2) >> 8) + (((int64_t)_bme280_calib.dig_P7) << 4);
|
|
return (float)p / 256;
|
|
}
|
|
|
|
/*!
|
|
* @brief Returns the humidity from the sensor
|
|
* @returns the humidity value read from the device
|
|
*/
|
|
float Adafruit_BME280::readHumidity(void) {
|
|
readTemperature(); // must be done first to get t_fine
|
|
|
|
int32_t adc_H = read16(BME280_REGISTER_HUMIDDATA);
|
|
if (adc_H == 0x8000) // value in case humidity measurement was disabled
|
|
return NAN;
|
|
|
|
int32_t v_x1_u32r;
|
|
|
|
v_x1_u32r = (t_fine - ((int32_t)76800));
|
|
|
|
v_x1_u32r = (((((adc_H << 14) - (((int32_t)_bme280_calib.dig_H4) << 20) -
|
|
(((int32_t)_bme280_calib.dig_H5) * v_x1_u32r)) +
|
|
((int32_t)16384)) >>
|
|
15) *
|
|
(((((((v_x1_u32r * ((int32_t)_bme280_calib.dig_H6)) >> 10) *
|
|
(((v_x1_u32r * ((int32_t)_bme280_calib.dig_H3)) >> 11) +
|
|
((int32_t)32768))) >>
|
|
10) +
|
|
((int32_t)2097152)) *
|
|
((int32_t)_bme280_calib.dig_H2) +
|
|
8192) >>
|
|
14));
|
|
|
|
v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) *
|
|
((int32_t)_bme280_calib.dig_H1)) >>
|
|
4));
|
|
|
|
v_x1_u32r = (v_x1_u32r < 0) ? 0 : v_x1_u32r;
|
|
v_x1_u32r = (v_x1_u32r > 419430400) ? 419430400 : v_x1_u32r;
|
|
float h = (v_x1_u32r >> 12);
|
|
return h / 1024.0;
|
|
}
|
|
|
|
/*!
|
|
* Calculates the altitude (in meters) from the specified atmospheric
|
|
* pressure (in hPa), and sea-level pressure (in hPa).
|
|
* @param seaLevel Sea-level pressure in hPa
|
|
* @returns the altitude value read from the device
|
|
*/
|
|
float Adafruit_BME280::readAltitude(float seaLevel) {
|
|
// Equation taken from BMP180 datasheet (page 16):
|
|
// http://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf
|
|
|
|
// Note that using the equation from wikipedia can give bad results
|
|
// at high altitude. See this thread for more information:
|
|
// http://forums.adafruit.com/viewtopic.php?f=22&t=58064
|
|
|
|
float atmospheric = readPressure() / 100.0F;
|
|
return 44330.0 * (1.0 - pow(atmospheric / seaLevel, 0.1903));
|
|
}
|
|
|
|
/*!
|
|
* Calculates the pressure at sea level (in hPa) from the specified
|
|
* altitude (in meters), and atmospheric pressure (in hPa).
|
|
* @param altitude Altitude in meters
|
|
* @param atmospheric Atmospheric pressure in hPa
|
|
* @returns the pressure at sea level (in hPa) from the specified altitude
|
|
*/
|
|
float Adafruit_BME280::seaLevelForAltitude(float altitude, float atmospheric) {
|
|
// Equation taken from BMP180 datasheet (page 17):
|
|
// http://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf
|
|
|
|
// Note that using the equation from wikipedia can give bad results
|
|
// at high altitude. See this thread for more information:
|
|
// http://forums.adafruit.com/viewtopic.php?f=22&t=58064
|
|
|
|
return atmospheric / pow(1.0 - (altitude / 44330.0), 5.255);
|
|
}
|
|
|
|
/*!
|
|
* Returns Sensor ID found by init() for diagnostics
|
|
* @returns Sensor ID 0x60 for BME280, 0x56, 0x57, 0x58 BMP280
|
|
*/
|
|
uint32_t Adafruit_BME280::sensorID(void) { return _sensorID; }
|