503 lines
16 KiB
C++
503 lines
16 KiB
C++
/***************************************************************************
|
|
This is a library for the BME280 humidity, temperature & pressure sensor
|
|
|
|
Designed specifically to work with the Adafruit BME280 Breakout
|
|
----> http://www.adafruit.com/products/2650
|
|
|
|
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
|
|
to interface.
|
|
|
|
Adafruit invests time and resources providing this open source code,
|
|
please support Adafruit andopen-source hardware by purchasing products
|
|
from Adafruit!
|
|
|
|
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
|
|
BSD license, all text above must be included in any redistribution
|
|
***************************************************************************/
|
|
#include "Arduino.h"
|
|
#include <Wire.h>
|
|
#include <SPI.h>
|
|
#include "Adafruit_BME280.h"
|
|
|
|
/***************************************************************************
|
|
PRIVATE FUNCTIONS
|
|
***************************************************************************/
|
|
Adafruit_BME280::Adafruit_BME280()
|
|
: _cs(-1), _mosi(-1), _miso(-1), _sck(-1)
|
|
{ }
|
|
|
|
Adafruit_BME280::Adafruit_BME280(int8_t cspin)
|
|
: _cs(cspin), _mosi(-1), _miso(-1), _sck(-1)
|
|
{ }
|
|
|
|
Adafruit_BME280::Adafruit_BME280(int8_t cspin, int8_t mosipin, int8_t misopin, int8_t sckpin)
|
|
: _cs(cspin), _mosi(mosipin), _miso(misopin), _sck(sckpin)
|
|
{ }
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Initialise sensor with given parameters / settings
|
|
*/
|
|
/**************************************************************************/
|
|
bool Adafruit_BME280::begin(uint8_t addr)
|
|
{
|
|
_i2caddr = addr;
|
|
|
|
// init I2C or SPI sensor interface
|
|
if (_cs == -1) {
|
|
// I2C
|
|
Wire.begin();
|
|
} else {
|
|
digitalWrite(_cs, HIGH);
|
|
pinMode(_cs, OUTPUT);
|
|
if (_sck == -1) {
|
|
// hardware SPI
|
|
SPI.begin();
|
|
} else {
|
|
// software SPI
|
|
pinMode(_sck, OUTPUT);
|
|
pinMode(_mosi, OUTPUT);
|
|
pinMode(_miso, INPUT);
|
|
}
|
|
}
|
|
|
|
// check if sensor, i.e. the chip ID is correct
|
|
if (read8(BME280_REGISTER_CHIPID) != 0x60)
|
|
return false;
|
|
|
|
// reset the device using soft-reset
|
|
// this makes sure the IIR is off, etc.
|
|
write8(BME280_REGISTER_SOFTRESET, 0xB6);
|
|
|
|
// wait for chip to wake up.
|
|
delay(300);
|
|
|
|
// if chip is still reading calibration, delay
|
|
while (isReadingCalibration())
|
|
delay(100);
|
|
|
|
readCoefficients(); // read trimming parameters, see DS 4.2.2
|
|
|
|
setSampling(); // use defaults
|
|
|
|
return true;
|
|
}
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief setup sensor with given parameters / settings
|
|
|
|
This is simply a overload to the normal begin()-function, so SPI users
|
|
don't get confused about the library requiring an address.
|
|
*/
|
|
/**************************************************************************/
|
|
|
|
|
|
void Adafruit_BME280::setSampling(sensor_mode mode,
|
|
sensor_sampling tempSampling,
|
|
sensor_sampling pressSampling,
|
|
sensor_sampling humSampling,
|
|
sensor_filter filter,
|
|
standby_duration duration) {
|
|
_measReg.mode = mode;
|
|
_measReg.osrs_t = tempSampling;
|
|
_measReg.osrs_p = pressSampling;
|
|
|
|
|
|
_humReg.osrs_h = humSampling;
|
|
_configReg.filter = filter;
|
|
_configReg.t_sb = duration;
|
|
|
|
|
|
// you must make sure to also set REGISTER_CONTROL after setting the
|
|
// CONTROLHUMID register, otherwise the values won't be applied (see DS 5.4.3)
|
|
write8(BME280_REGISTER_CONTROLHUMID, _humReg.get());
|
|
write8(BME280_REGISTER_CONFIG, _configReg.get());
|
|
write8(BME280_REGISTER_CONTROL, _measReg.get());
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Encapsulate hardware and software SPI transfer into one function
|
|
*/
|
|
/**************************************************************************/
|
|
uint8_t Adafruit_BME280::spixfer(uint8_t x) {
|
|
// hardware SPI
|
|
if (_sck == -1)
|
|
return SPI.transfer(x);
|
|
|
|
// software SPI
|
|
uint8_t reply = 0;
|
|
for (int i=7; i>=0; i--) {
|
|
reply <<= 1;
|
|
digitalWrite(_sck, LOW);
|
|
digitalWrite(_mosi, x & (1<<i));
|
|
digitalWrite(_sck, HIGH);
|
|
if (digitalRead(_miso))
|
|
reply |= 1;
|
|
}
|
|
return reply;
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Writes an 8 bit value over I2C or SPI
|
|
*/
|
|
/**************************************************************************/
|
|
void Adafruit_BME280::write8(byte reg, byte value) {
|
|
if (_cs == -1) {
|
|
Wire.beginTransmission((uint8_t)_i2caddr);
|
|
Wire.write((uint8_t)reg);
|
|
Wire.write((uint8_t)value);
|
|
Wire.endTransmission();
|
|
} else {
|
|
if (_sck == -1)
|
|
SPI.beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
|
|
digitalWrite(_cs, LOW);
|
|
spixfer(reg & ~0x80); // write, bit 7 low
|
|
spixfer(value);
|
|
digitalWrite(_cs, HIGH);
|
|
if (_sck == -1)
|
|
SPI.endTransaction(); // release the SPI bus
|
|
}
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Reads an 8 bit value over I2C or SPI
|
|
*/
|
|
/**************************************************************************/
|
|
uint8_t Adafruit_BME280::read8(byte reg) {
|
|
uint8_t value;
|
|
|
|
if (_cs == -1) {
|
|
Wire.beginTransmission((uint8_t)_i2caddr);
|
|
Wire.write((uint8_t)reg);
|
|
Wire.endTransmission();
|
|
Wire.requestFrom((uint8_t)_i2caddr, (byte)1);
|
|
value = Wire.read();
|
|
} else {
|
|
if (_sck == -1)
|
|
SPI.beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
|
|
digitalWrite(_cs, LOW);
|
|
spixfer(reg | 0x80); // read, bit 7 high
|
|
value = spixfer(0);
|
|
digitalWrite(_cs, HIGH);
|
|
if (_sck == -1)
|
|
SPI.endTransaction(); // release the SPI bus
|
|
}
|
|
return value;
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Reads a 16 bit value over I2C or SPI
|
|
*/
|
|
/**************************************************************************/
|
|
uint16_t Adafruit_BME280::read16(byte reg)
|
|
{
|
|
uint16_t value;
|
|
|
|
if (_cs == -1) {
|
|
Wire.beginTransmission((uint8_t)_i2caddr);
|
|
Wire.write((uint8_t)reg);
|
|
Wire.endTransmission();
|
|
Wire.requestFrom((uint8_t)_i2caddr, (byte)2);
|
|
value = (Wire.read() << 8) | Wire.read();
|
|
} else {
|
|
if (_sck == -1)
|
|
SPI.beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
|
|
digitalWrite(_cs, LOW);
|
|
spixfer(reg | 0x80); // read, bit 7 high
|
|
value = (spixfer(0) << 8) | spixfer(0);
|
|
digitalWrite(_cs, HIGH);
|
|
if (_sck == -1)
|
|
SPI.endTransaction(); // release the SPI bus
|
|
}
|
|
|
|
return value;
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
|
|
*/
|
|
/**************************************************************************/
|
|
uint16_t Adafruit_BME280::read16_LE(byte reg) {
|
|
uint16_t temp = read16(reg);
|
|
return (temp >> 8) | (temp << 8);
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Reads a signed 16 bit value over I2C or SPI
|
|
*/
|
|
/**************************************************************************/
|
|
int16_t Adafruit_BME280::readS16(byte reg)
|
|
{
|
|
return (int16_t)read16(reg);
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
|
|
*/
|
|
/**************************************************************************/
|
|
int16_t Adafruit_BME280::readS16_LE(byte reg)
|
|
{
|
|
return (int16_t)read16_LE(reg);
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Reads a 24 bit value over I2C
|
|
*/
|
|
/**************************************************************************/
|
|
uint32_t Adafruit_BME280::read24(byte reg)
|
|
{
|
|
uint32_t value;
|
|
|
|
if (_cs == -1) {
|
|
Wire.beginTransmission((uint8_t)_i2caddr);
|
|
Wire.write((uint8_t)reg);
|
|
Wire.endTransmission();
|
|
Wire.requestFrom((uint8_t)_i2caddr, (byte)3);
|
|
|
|
value = Wire.read();
|
|
value <<= 8;
|
|
value |= Wire.read();
|
|
value <<= 8;
|
|
value |= Wire.read();
|
|
} else {
|
|
if (_sck == -1)
|
|
SPI.beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0));
|
|
digitalWrite(_cs, LOW);
|
|
spixfer(reg | 0x80); // read, bit 7 high
|
|
|
|
value = spixfer(0);
|
|
value <<= 8;
|
|
value |= spixfer(0);
|
|
value <<= 8;
|
|
value |= spixfer(0);
|
|
|
|
digitalWrite(_cs, HIGH);
|
|
if (_sck == -1)
|
|
SPI.endTransaction(); // release the SPI bus
|
|
}
|
|
|
|
return value;
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Take a new measurement (only possible in forced mode)
|
|
*/
|
|
/**************************************************************************/
|
|
void Adafruit_BME280::takeForcedMeasurement()
|
|
{
|
|
// If we are in forced mode, the BME sensor goes back to sleep after each
|
|
// measurement and we need to set it to forced mode once at this point, so
|
|
// it will take the next measurement and then return to sleep again.
|
|
// In normal mode simply does new measurements periodically.
|
|
if (_measReg.mode == MODE_FORCED) {
|
|
// set to forced mode, i.e. "take next measurement"
|
|
write8(BME280_REGISTER_CONTROL, _measReg.get());
|
|
// wait until measurement has been completed, otherwise we would read
|
|
// the values from the last measurement
|
|
while (read8(BME280_REGISTER_STATUS) & 0x08)
|
|
delay(1);
|
|
}
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Reads the factory-set coefficients
|
|
*/
|
|
/**************************************************************************/
|
|
void Adafruit_BME280::readCoefficients(void)
|
|
{
|
|
_bme280_calib.dig_T1 = read16_LE(BME280_REGISTER_DIG_T1);
|
|
_bme280_calib.dig_T2 = readS16_LE(BME280_REGISTER_DIG_T2);
|
|
_bme280_calib.dig_T3 = readS16_LE(BME280_REGISTER_DIG_T3);
|
|
|
|
_bme280_calib.dig_P1 = read16_LE(BME280_REGISTER_DIG_P1);
|
|
_bme280_calib.dig_P2 = readS16_LE(BME280_REGISTER_DIG_P2);
|
|
_bme280_calib.dig_P3 = readS16_LE(BME280_REGISTER_DIG_P3);
|
|
_bme280_calib.dig_P4 = readS16_LE(BME280_REGISTER_DIG_P4);
|
|
_bme280_calib.dig_P5 = readS16_LE(BME280_REGISTER_DIG_P5);
|
|
_bme280_calib.dig_P6 = readS16_LE(BME280_REGISTER_DIG_P6);
|
|
_bme280_calib.dig_P7 = readS16_LE(BME280_REGISTER_DIG_P7);
|
|
_bme280_calib.dig_P8 = readS16_LE(BME280_REGISTER_DIG_P8);
|
|
_bme280_calib.dig_P9 = readS16_LE(BME280_REGISTER_DIG_P9);
|
|
|
|
_bme280_calib.dig_H1 = read8(BME280_REGISTER_DIG_H1);
|
|
_bme280_calib.dig_H2 = readS16_LE(BME280_REGISTER_DIG_H2);
|
|
_bme280_calib.dig_H3 = read8(BME280_REGISTER_DIG_H3);
|
|
_bme280_calib.dig_H4 = (read8(BME280_REGISTER_DIG_H4) << 4) | (read8(BME280_REGISTER_DIG_H4+1) & 0xF);
|
|
_bme280_calib.dig_H5 = (read8(BME280_REGISTER_DIG_H5+1) << 4) | (read8(BME280_REGISTER_DIG_H5) >> 4);
|
|
_bme280_calib.dig_H6 = (int8_t)read8(BME280_REGISTER_DIG_H6);
|
|
}
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief return true if chip is busy reading cal data
|
|
*/
|
|
/**************************************************************************/
|
|
bool Adafruit_BME280::isReadingCalibration(void)
|
|
{
|
|
uint8_t const rStatus = read8(BME280_REGISTER_STATUS);
|
|
|
|
return (rStatus & (1 << 0)) != 0;
|
|
}
|
|
|
|
|
|
/**************************************************************************/
|
|
/*!
|
|
@brief Returns the temperature from the sensor
|
|
*/
|
|
/**************************************************************************/
|
|
float Adafruit_BME280::readTemperature(void)
|
|
{
|
|
int32_t var1, var2;
|
|
|
|
int32_t adc_T = read24(BME280_REGISTER_TEMPDATA);
|
|
if (adc_T == 0x800000) // value in case temp measurement was disabled
|
|
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);
|
|
}
|