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SparkFunBME280.cpp
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/******************************************************************************
Modded by NePe to fix some problems!!!
SparkFunBME280.cpp
BME280 Arduino and Teensy Driver
Marshall Taylor @ SparkFun Electronics
May 20, 2015
https://github.com/sparkfun/BME280_Breakout
Resources:
Uses Wire.h for i2c operation
Development environment specifics:
Arduino IDE 1.6.4
Teensy loader 1.23
This code is released under the [MIT License](http://opensource.org/licenses/MIT).
Please review the LICENSE.md file included with this example. If you have any questions
or concerns with licensing, please contact [email protected].
Distributed as-is; no warranty is given.
******************************************************************************/
//See SparkFunBME280.h for additional topology notes.
#include <Wire.h>
#include "SparkFunBME280.h"
#include <math.h>
BME280::BME280(void) {
settings.I2CAddress = 0x77;
settings.runMode = 1;
settings.tStandby = 0;
settings.filter = 0;
settings.tempOverSample = 5;
settings.pressOverSample = 5;
settings.humidOverSample = 5;
}
uint8_t BME280::begin() {
uint8_t dataToWrite = 0;
Wire.begin();
calibration.dig_T1 = ((uint16_t)((readRegister(BME280_DIG_T1_MSB_REG) << 8) + readRegister(BME280_DIG_T1_LSB_REG)));
calibration.dig_T2 = ((int16_t)((readRegister(BME280_DIG_T2_MSB_REG) << 8) + readRegister(BME280_DIG_T2_LSB_REG)));
calibration.dig_T3 = ((int16_t)((readRegister(BME280_DIG_T3_MSB_REG) << 8) + readRegister(BME280_DIG_T3_LSB_REG)));
calibration.dig_P1 = ((uint16_t)((readRegister(BME280_DIG_P1_MSB_REG) << 8) + readRegister(BME280_DIG_P1_LSB_REG)));
calibration.dig_P2 = ((int16_t)((readRegister(BME280_DIG_P2_MSB_REG) << 8) + readRegister(BME280_DIG_P2_LSB_REG)));
calibration.dig_P3 = ((int16_t)((readRegister(BME280_DIG_P3_MSB_REG) << 8) + readRegister(BME280_DIG_P3_LSB_REG)));
calibration.dig_P4 = ((int16_t)((readRegister(BME280_DIG_P4_MSB_REG) << 8) + readRegister(BME280_DIG_P4_LSB_REG)));
calibration.dig_P5 = ((int16_t)((readRegister(BME280_DIG_P5_MSB_REG) << 8) + readRegister(BME280_DIG_P5_LSB_REG)));
calibration.dig_P6 = ((int16_t)((readRegister(BME280_DIG_P6_MSB_REG) << 8) + readRegister(BME280_DIG_P6_LSB_REG)));
calibration.dig_P7 = ((int16_t)((readRegister(BME280_DIG_P7_MSB_REG) << 8) + readRegister(BME280_DIG_P7_LSB_REG)));
calibration.dig_P8 = ((int16_t)((readRegister(BME280_DIG_P8_MSB_REG) << 8) + readRegister(BME280_DIG_P8_LSB_REG)));
calibration.dig_P9 = ((int16_t)((readRegister(BME280_DIG_P9_MSB_REG) << 8) + readRegister(BME280_DIG_P9_LSB_REG)));
calibration.dig_H1 = ((uint8_t)(readRegister(BME280_DIG_H1_REG)));
calibration.dig_H2 = ((int16_t)((readRegister(BME280_DIG_H2_MSB_REG) << 8) + readRegister(BME280_DIG_H2_LSB_REG)));
calibration.dig_H3 = ((uint8_t)(readRegister(BME280_DIG_H3_REG)));
calibration.dig_H4 = ((int16_t)((readRegister(BME280_DIG_H4_MSB_REG) << 4) + (readRegister(BME280_DIG_H4_LSB_REG) & 0x0F)));
calibration.dig_H5 = ((int16_t)((readRegister(BME280_DIG_H5_MSB_REG) << 4) + ((readRegister(BME280_DIG_H4_LSB_REG) >> 4) & 0x0F)));
calibration.dig_H6 = ((uint8_t)readRegister(BME280_DIG_H6_REG));
writeRegister(BME280_CTRL_MEAS_REG, 0x00);
dataToWrite = (settings.tStandby << 0x5) & 0xE0;
dataToWrite |= (settings.filter << 0x02) & 0x1C;
writeRegister(BME280_CONFIG_REG, dataToWrite);
dataToWrite = settings.humidOverSample & 0x07;
writeRegister(BME280_CTRL_HUMIDITY_REG, dataToWrite);
dataToWrite = (settings.tempOverSample << 0x5) & 0xE0;
dataToWrite |= (settings.pressOverSample << 0x02) & 0x1C;
dataToWrite |= (settings.runMode) & 0x03;
writeRegister(BME280_CTRL_MEAS_REG, dataToWrite);
return readRegister(0xD0);
}
void BME280::reset(void) {
writeRegister(BME280_RST_REG, 0xB6);
}
int32_t BME280::readPressure(void) {
int32_t adc_P = ((uint32_t)readRegister(BME280_PRESSURE_MSB_REG) << 12) | ((uint32_t)readRegister(BME280_PRESSURE_LSB_REG) << 4) | ((readRegister(BME280_PRESSURE_XLSB_REG) >> 4) & 0x0F);
int64_t var1, var2, p_acc;
var1 = ((int64_t)t_fine) - 128000;
var2 = var1 * var1 * (int64_t)calibration.dig_P6;
var2 = var2 + ((var1 * (int64_t)calibration.dig_P5)<<17);
var2 = var2 + (((int64_t)calibration.dig_P4)<<35);
var1 = ((var1 * var1 * (int64_t)calibration.dig_P3)>>8) + ((var1 * (int64_t)calibration.dig_P2)<<12);
var1 = (((((int64_t)1)<<47)+var1))*((int64_t)calibration.dig_P1)>>33;
if (var1 == 0)
return 0;
p_acc = 1048576 - adc_P;
p_acc = (((p_acc<<31) - var2)*3125)/var1;
var1 = (((int64_t)calibration.dig_P9) * (p_acc>>13) * (p_acc>>13)) >> 25;
var2 = (((int64_t)calibration.dig_P8) * p_acc) >> 19;
p_acc = ((p_acc + var1 + var2) >> 8) + (((int64_t)calibration.dig_P7)<<4);
return p_acc / 256;
}
float BME280::readHumidity(void) {
int32_t adc_H = ((uint32_t)readRegister(BME280_HUMIDITY_MSB_REG) << 8) | ((uint32_t)readRegister(BME280_HUMIDITY_LSB_REG));
int32_t var1;
var1 = (t_fine - ((int32_t)76800));
var1 = (((((adc_H << 14) - (((int32_t)calibration.dig_H4) << 20) - (((int32_t)calibration.dig_H5) * var1)) +
((int32_t)16384)) >> 15) * (((((((var1 * ((int32_t)calibration.dig_H6)) >> 10) * (((var1 * ((int32_t)calibration.dig_H3)) >> 11) + ((int32_t)32768))) >> 10) + ((int32_t)2097152)) *
((int32_t)calibration.dig_H2) + 8192) >> 14));
var1 = (var1 - (((((var1 >> 15) * (var1 >> 15)) >> 7) * ((int32_t)calibration.dig_H1)) >> 4));
var1 = (var1 < 0 ? 0 : var1);
var1 = (var1 > 419430400 ? 419430400 : var1);
return (float)(var1>>12) / 1024.0;
}
float BME280::readTemperature(void) {
int32_t adc_T = ((uint32_t)readRegister(BME280_TEMPERATURE_MSB_REG) << 12) | ((uint32_t)readRegister(BME280_TEMPERATURE_LSB_REG) << 4) | ((readRegister(BME280_TEMPERATURE_XLSB_REG) >> 4) & 0x0F);
int64_t var1, var2;
var1 = ((((adc_T>>3) - ((int32_t)calibration.dig_T1<<1))) * ((int32_t)calibration.dig_T2)) >> 11;
var2 = (((((adc_T>>4) - ((int32_t)calibration.dig_T1)) * ((adc_T>>4) - ((int32_t)calibration.dig_T1))) >> 12) *
((int32_t)calibration.dig_T3)) >> 14;
t_fine = var1 + var2;
float output = (t_fine * 5 + 128) >> 8;
output = output / 100;
return output;
}
void BME280::readRegisterRegion(uint8_t *outputPointer , uint8_t offset, uint8_t length) {
uint8_t i = 0;
char c = 0;
Wire.beginTransmission(settings.I2CAddress);
Wire.write(offset);
Wire.endTransmission();
Wire.requestFrom(settings.I2CAddress, length);
while ((Wire.available()) && (i < length)) {
c = Wire.read();
*outputPointer = c;
outputPointer++;
i++;
}
}
uint8_t BME280::readRegister(uint8_t offset) {
uint8_t result;
uint8_t numBytes = 1;
Wire.beginTransmission(settings.I2CAddress);
Wire.write(offset);
Wire.endTransmission();
Wire.requestFrom(settings.I2CAddress, numBytes);
while (Wire.available())
result = Wire.read();
return result;
}
int16_t BME280::readRegisterInt16(uint8_t offset) {
uint8_t myBuffer[2];
readRegisterRegion(myBuffer, offset, 2);
int16_t output = (int16_t)myBuffer[0] | int16_t(myBuffer[1] << 8);
return output;
}
void BME280::writeRegister(uint8_t offset, uint8_t dataToWrite) {
Wire.beginTransmission(settings.I2CAddress);
Wire.write(offset);
Wire.write(dataToWrite);
Wire.endTransmission();
}