503 lines
16 KiB
C++
503 lines
16 KiB
C++
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/***************************************************************************
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This is a library for the BME280 humidity, temperature & pressure sensor
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Designed specifically to work with the Adafruit BME280 Breakout
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----> http://www.adafruit.com/products/2650
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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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Adafruit invests time and resources providing this open source code,
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please support Adafruit andopen-source hardware by purchasing products
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from Adafruit!
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Written by Limor Fried & Kevin Townsend for Adafruit Industries.
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BSD license, all text above must be included in any redistribution
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***************************************************************************/
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#include "Arduino.h"
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#include <Wire.h>
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#include <SPI.h>
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#include "Adafruit_BME280.h"
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/***************************************************************************
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PRIVATE FUNCTIONS
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***************************************************************************/
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Adafruit_BME280::Adafruit_BME280()
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: _cs(-1), _mosi(-1), _miso(-1), _sck(-1)
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{ }
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Adafruit_BME280::Adafruit_BME280(int8_t cspin)
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: _cs(cspin), _mosi(-1), _miso(-1), _sck(-1)
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{ }
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Adafruit_BME280::Adafruit_BME280(int8_t cspin, int8_t mosipin, int8_t misopin, int8_t sckpin)
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: _cs(cspin), _mosi(mosipin), _miso(misopin), _sck(sckpin)
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{ }
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/**************************************************************************/
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/*!
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@brief Initialise sensor with given parameters / settings
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*/
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/**************************************************************************/
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bool Adafruit_BME280::begin(uint8_t addr)
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{
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_i2caddr = addr;
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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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if (read8(BME280_REGISTER_CHIPID) != 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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return true;
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}
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/**************************************************************************/
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/*!
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@brief setup sensor with given parameters / settings
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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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*/
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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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// 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 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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/*!
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@brief Encapsulate hardware and software SPI transfer into one function
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*/
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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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/*!
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@brief Writes an 8 bit value over I2C or SPI
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*/
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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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/*!
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@brief Reads an 8 bit value over I2C or SPI
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*/
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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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/*!
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@brief Reads a 16 bit value over I2C or SPI
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*/
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/**************************************************************************/
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uint16_t Adafruit_BME280::read16(byte reg)
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{
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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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/*!
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*/
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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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/*!
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@brief Reads a signed 16 bit value over I2C or SPI
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*/
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/**************************************************************************/
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int16_t Adafruit_BME280::readS16(byte reg)
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{
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return (int16_t)read16(reg);
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}
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/**************************************************************************/
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/*!
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*/
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/**************************************************************************/
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int16_t Adafruit_BME280::readS16_LE(byte reg)
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{
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return (int16_t)read16_LE(reg);
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}
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/**************************************************************************/
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/*!
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@brief Reads a 24 bit value over I2C
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*/
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/**************************************************************************/
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uint32_t Adafruit_BME280::read24(byte reg)
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{
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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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/*!
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@brief Take a new measurement (only possible in forced mode)
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*/
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/**************************************************************************/
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void Adafruit_BME280::takeForcedMeasurement()
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{
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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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/*!
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@brief Reads the factory-set coefficients
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*/
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/**************************************************************************/
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void Adafruit_BME280::readCoefficients(void)
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{
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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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_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) | (read8(BME280_REGISTER_DIG_H4+1) & 0xF);
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_bme280_calib.dig_H5 = (read8(BME280_REGISTER_DIG_H5+1) << 4) | (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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/*!
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@brief return true if chip is busy reading cal data
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*/
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/**************************************************************************/
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bool Adafruit_BME280::isReadingCalibration(void)
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{
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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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/*!
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@brief Returns the temperature from the sensor
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*/
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/**************************************************************************/
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float Adafruit_BME280::readTemperature(void)
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{
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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;
|
||
|
|
adc_T >>= 4;
|
||
|
|
|
||
|
|
var1 = ((((adc_T>>3) - ((int32_t)_bme280_calib.dig_T1 <<1))) *
|
||
|
|
((int32_t)_bme280_calib.dig_T2)) >> 11;
|
||
|
|
|
||
|
|
var2 = (((((adc_T>>4) - ((int32_t)_bme280_calib.dig_T1)) *
|
||
|
|
((adc_T>>4) - ((int32_t)_bme280_calib.dig_T1))) >> 12) *
|
||
|
|
((int32_t)_bme280_calib.dig_T3)) >> 14;
|
||
|
|
|
||
|
|
t_fine = var1 + var2;
|
||
|
|
|
||
|
|
float T = (t_fine * 5 + 128) >> 8;
|
||
|
|
return T/100;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**************************************************************************/
|
||
|
|
/*!
|
||
|
|
@brief Returns the temperature from the sensor
|
||
|
|
*/
|
||
|
|
/**************************************************************************/
|
||
|
|
float Adafruit_BME280::readPressure(void) {
|
||
|
|
int64_t var1, var2, p;
|
||
|
|
|
||
|
|
readTemperature(); // must be done first to get t_fine
|
||
|
|
|
||
|
|
int32_t adc_P = read24(BME280_REGISTER_PRESSUREDATA);
|
||
|
|
if (adc_P == 0x800000) // value in case pressure measurement was disabled
|
||
|
|
return NAN;
|
||
|
|
adc_P >>= 4;
|
||
|
|
|
||
|
|
var1 = ((int64_t)t_fine) - 128000;
|
||
|
|
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
|
||
|
|
*/
|
||
|
|
/**************************************************************************/
|
||
|
|
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
|
||
|
|
@param atmospheric Atmospheric pressure in hPa
|
||
|
|
*/
|
||
|
|
/**************************************************************************/
|
||
|
|
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
|
||
|
|
*/
|
||
|
|
/**************************************************************************/
|
||
|
|
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);
|
||
|
|
}
|