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@ladyada @tdicola
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/***************************************************
This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp sensor
Designed specifically to work with the Adafruit BMP085 or BMP180 Breakout
----> http://www.adafruit.com/products/391
----> http://www.adafruit.com/products/1603
These displays use I2C to communicate, 2 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#include "Adafruit_BMP085.h"
Adafruit_BMP085::Adafruit_BMP085() {
}
boolean Adafruit_BMP085::begin(uint8_t mode) {
if (mode > BMP085_ULTRAHIGHRES)
mode = BMP085_ULTRAHIGHRES;
oversampling = mode;
Wire.begin();
if (read8(0xD0) != 0x55) return false;
/* read calibration data */
ac1 = read16(BMP085_CAL_AC1);
ac2 = read16(BMP085_CAL_AC2);
ac3 = read16(BMP085_CAL_AC3);
ac4 = read16(BMP085_CAL_AC4);
ac5 = read16(BMP085_CAL_AC5);
ac6 = read16(BMP085_CAL_AC6);
b1 = read16(BMP085_CAL_B1);
b2 = read16(BMP085_CAL_B2);
mb = read16(BMP085_CAL_MB);
mc = read16(BMP085_CAL_MC);
md = read16(BMP085_CAL_MD);
#if (BMP085_DEBUG == 1)
Serial.print("ac1 = "); Serial.println(ac1, DEC);
Serial.print("ac2 = "); Serial.println(ac2, DEC);
Serial.print("ac3 = "); Serial.println(ac3, DEC);
Serial.print("ac4 = "); Serial.println(ac4, DEC);
Serial.print("ac5 = "); Serial.println(ac5, DEC);
Serial.print("ac6 = "); Serial.println(ac6, DEC);
Serial.print("b1 = "); Serial.println(b1, DEC);
Serial.print("b2 = "); Serial.println(b2, DEC);
Serial.print("mb = "); Serial.println(mb, DEC);
Serial.print("mc = "); Serial.println(mc, DEC);
Serial.print("md = "); Serial.println(md, DEC);
#endif
return true;
}
int32_t Adafruit_BMP085::computeB5(int32_t UT) {
int32_t X1 = (UT - (int32_t)ac6) * ((int32_t)ac5) >> 15;
int32_t X2 = ((int32_t)mc << 11) / (X1+(int32_t)md);
return X1 + X2;
}
uint16_t Adafruit_BMP085::readRawTemperature(void) {
write8(BMP085_CONTROL, BMP085_READTEMPCMD);
delay(5);
#if BMP085_DEBUG == 1
Serial.print("Raw temp: "); Serial.println(read16(BMP085_TEMPDATA));
#endif
return read16(BMP085_TEMPDATA);
}
uint32_t Adafruit_BMP085::readRawPressure(void) {
uint32_t raw;
write8(BMP085_CONTROL, BMP085_READPRESSURECMD + (oversampling << 6));
if (oversampling == BMP085_ULTRALOWPOWER)
delay(5);
else if (oversampling == BMP085_STANDARD)
delay(8);
else if (oversampling == BMP085_HIGHRES)
delay(14);
else
delay(26);
raw = read16(BMP085_PRESSUREDATA);
raw <<= 8;
raw |= read8(BMP085_PRESSUREDATA+2);
raw >>= (8 - oversampling);
/* this pull broke stuff, look at it later?
if (oversampling==0) {
raw <<= 8;
raw |= read8(BMP085_PRESSUREDATA+2);
raw >>= (8 - oversampling);
}
*/
#if BMP085_DEBUG == 1
Serial.print("Raw pressure: "); Serial.println(raw);
#endif
return raw;
}
int32_t Adafruit_BMP085::readPressure(void) {
int32_t UT, UP, B3, B5, B6, X1, X2, X3, p;
uint32_t B4, B7;
UT = readRawTemperature();
UP = readRawPressure();
#if BMP085_DEBUG == 1
// use datasheet numbers!
UT = 27898;
UP = 23843;
ac6 = 23153;
ac5 = 32757;
mc = -8711;
md = 2868;
b1 = 6190;
b2 = 4;
ac3 = -14383;
ac2 = -72;
ac1 = 408;
ac4 = 32741;
oversampling = 0;
#endif
B5 = computeB5(UT);
#if BMP085_DEBUG == 1
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
Serial.print("B5 = "); Serial.println(B5);
#endif
// do pressure calcs
B6 = B5 - 4000;
X1 = ((int32_t)b2 * ( (B6 * B6)>>12 )) >> 11;
X2 = ((int32_t)ac2 * B6) >> 11;
X3 = X1 + X2;
B3 = ((((int32_t)ac1*4 + X3) << oversampling) + 2) / 4;
#if BMP085_DEBUG == 1
Serial.print("B6 = "); Serial.println(B6);
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
Serial.print("B3 = "); Serial.println(B3);
#endif
X1 = ((int32_t)ac3 * B6) >> 13;
X2 = ((int32_t)b1 * ((B6 * B6) >> 12)) >> 16;
X3 = ((X1 + X2) + 2) >> 2;
B4 = ((uint32_t)ac4 * (uint32_t)(X3 + 32768)) >> 15;
B7 = ((uint32_t)UP - B3) * (uint32_t)( 50000UL >> oversampling );
#if BMP085_DEBUG == 1
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
Serial.print("B4 = "); Serial.println(B4);
Serial.print("B7 = "); Serial.println(B7);
#endif
if (B7 < 0x80000000) {
p = (B7 * 2) / B4;
} else {
p = (B7 / B4) * 2;
}
X1 = (p >> 8) * (p >> 8);
X1 = (X1 * 3038) >> 16;
X2 = (-7357 * p) >> 16;
#if BMP085_DEBUG == 1
Serial.print("p = "); Serial.println(p);
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
#endif
p = p + ((X1 + X2 + (int32_t)3791)>>4);
#if BMP085_DEBUG == 1
Serial.print("p = "); Serial.println(p);
#endif
return p;
}
int32_t Adafruit_BMP085::readSealevelPressure(float altitude_meters) {
float pressure = readPressure();
return (int32_t)(pressure / pow(1.0-altitude_meters/44330, 5.255));
}
float Adafruit_BMP085::readTemperature(void) {
int32_t UT, B5; // following ds convention
float temp;
UT = readRawTemperature();
#if BMP085_DEBUG == 1
// use datasheet numbers!
UT = 27898;
ac6 = 23153;
ac5 = 32757;
mc = -8711;
md = 2868;
#endif
B5 = computeB5(UT);
temp = (B5+8) >> 4;
temp /= 10;
return temp;
}
float Adafruit_BMP085::readAltitude(float sealevelPressure) {
float altitude;
float pressure = readPressure();
altitude = 44330 * (1.0 - pow(pressure /sealevelPressure,0.1903));
return altitude;
}
/*********************************************************************/
uint8_t Adafruit_BMP085::read8(uint8_t a) {
uint8_t ret;
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
#if (ARDUINO >= 100)
Wire.write(a); // sends register address to read from
#else
Wire.send(a); // sends register address to read from
#endif
Wire.endTransmission(); // end transmission
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.requestFrom(BMP085_I2CADDR, 1);// send data n-bytes read
#if (ARDUINO >= 100)
ret = Wire.read(); // receive DATA
#else
ret = Wire.receive(); // receive DATA
#endif
Wire.endTransmission(); // end transmission
return ret;
}
uint16_t Adafruit_BMP085::read16(uint8_t a) {
uint16_t ret;
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
#if (ARDUINO >= 100)
Wire.write(a); // sends register address to read from
#else
Wire.send(a); // sends register address to read from
#endif
Wire.endTransmission(); // end transmission
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.requestFrom(BMP085_I2CADDR, 2);// send data n-bytes read
#if (ARDUINO >= 100)
ret = Wire.read(); // receive DATA
ret <<= 8;
ret |= Wire.read(); // receive DATA
#else
ret = Wire.receive(); // receive DATA
ret <<= 8;
ret |= Wire.receive(); // receive DATA
#endif
Wire.endTransmission(); // end transmission
return ret;
}
void Adafruit_BMP085::write8(uint8_t a, uint8_t d) {
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
#if (ARDUINO >= 100)
Wire.write(a); // sends register address to read from
Wire.write(d); // write data
#else
Wire.send(a); // sends register address to read from
Wire.send(d); // write data
#endif
Wire.endTransmission(); // end transmission
}
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