Cansat
/
esp32_Adafruit_BME280_Library
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
esp32_Adafruit_BME280_Library/Adafruit_BME280.cpp

338 lines
10 KiB
C++
Raw Blame History

/***************************************************************************
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)
{ }
bool Adafruit_BME280::begin(uint8_t a) {
_i2caddr = a;
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);
}
}
if (read8(BME280_REGISTER_CHIPID) != 0x60)
return false;
readCoefficients();
write8(BME280_REGISTER_CONTROLHUMID, 0x03); // Set before CONTROL (DS 5.4.3)
write8(BME280_REGISTER_CONTROL, 0x3F);
return true;
}
uint8_t Adafruit_BME280::spixfer(uint8_t x) {
if (_sck == -1)
return SPI.transfer(x);
// software spi
//Serial.println("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/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
*/
/**************************************************************************/
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();
Wire.endTransmission();
} 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
*/
/**************************************************************************/
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();
Wire.endTransmission();
} 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
*/
/**************************************************************************/
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 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);
}
/**************************************************************************/
/*!
*/
/**************************************************************************/
float Adafruit_BME280::readTemperature(void)
{
int32_t var1, var2;
int32_t adc_T = read16(BME280_REGISTER_TEMPDATA);
adc_T <<= 8;
adc_T |= read8(BME280_REGISTER_TEMPDATA+2);
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;
}
/**************************************************************************/
/*!
*/
/**************************************************************************/
float Adafruit_BME280::readPressure(void) {
int64_t var1, var2, p;
readTemperature(); // must be done first to get t_fine
int32_t adc_P = read16(BME280_REGISTER_PRESSUREDATA);
adc_P <<= 8;
adc_P |= read8(BME280_REGISTER_PRESSUREDATA+2);
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;
}
/**************************************************************************/
/*!
*/
/**************************************************************************/
float Adafruit_BME280::readHumidity(void) {
readTemperature(); // must be done first to get t_fine
int32_t adc_H = read16(BME280_REGISTER_HUMIDDATA);
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));
}
Reference in New Issue View Git Blame Copy Permalink