311 lines
6.8 KiB
C++
311 lines
6.8 KiB
C++
/*!
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* @file Adafruit_BMP085.cpp
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*
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* @mainpage Adafruit BMP085 Library
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*
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* @section intro_sec Introduction
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*
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* This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp
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* sensor
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*
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* Designed specifically to work with the Adafruit BMP085 or BMP180 Breakout
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* ----> http://www.adafruit.com/products/391
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* ----> http://www.adafruit.com/products/1603
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*
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* These displays use I2C to communicate, 2 pins are required to
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* interface
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit and open-source hardware by purchasing
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* products from Adafruit!
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*
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* @section author Author
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*
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* Written by Limor Fried/Ladyada for Adafruit Industries.
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* Updated by Samy Kamkar for cross-platform support.
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*
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* @section license License
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*
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* BSD license, all text above must be included in any redistribution
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*/
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#include "Adafruit_BMP085.h"
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#include <Adafruit_I2CDevice.h>
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Adafruit_BMP085::Adafruit_BMP085() { i2c_dev = nullptr; }
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bool Adafruit_BMP085::begin(uint8_t mode, TwoWire *wire) {
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if (mode > BMP085_ULTRAHIGHRES)
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mode = BMP085_ULTRAHIGHRES;
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oversampling = mode;
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if (i2c_dev) {
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delete i2c_dev; // remove old interface
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}
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i2c_dev = new Adafruit_I2CDevice(BMP085_I2CADDR, wire);
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if (!i2c_dev->begin()) {
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return false;
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}
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if (read8(0xD0) != 0x55)
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return false;
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/* read calibration data */
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ac1 = read16(BMP085_CAL_AC1);
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ac2 = read16(BMP085_CAL_AC2);
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ac3 = read16(BMP085_CAL_AC3);
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ac4 = read16(BMP085_CAL_AC4);
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ac5 = read16(BMP085_CAL_AC5);
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ac6 = read16(BMP085_CAL_AC6);
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b1 = read16(BMP085_CAL_B1);
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b2 = read16(BMP085_CAL_B2);
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mb = read16(BMP085_CAL_MB);
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mc = read16(BMP085_CAL_MC);
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md = read16(BMP085_CAL_MD);
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#if (BMP085_DEBUG == 1)
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Serial.print("ac1 = ");
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Serial.println(ac1, DEC);
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Serial.print("ac2 = ");
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Serial.println(ac2, DEC);
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Serial.print("ac3 = ");
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Serial.println(ac3, DEC);
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Serial.print("ac4 = ");
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Serial.println(ac4, DEC);
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Serial.print("ac5 = ");
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Serial.println(ac5, DEC);
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Serial.print("ac6 = ");
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Serial.println(ac6, DEC);
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Serial.print("b1 = ");
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Serial.println(b1, DEC);
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Serial.print("b2 = ");
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Serial.println(b2, DEC);
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Serial.print("mb = ");
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Serial.println(mb, DEC);
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Serial.print("mc = ");
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Serial.println(mc, DEC);
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Serial.print("md = ");
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Serial.println(md, DEC);
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#endif
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return true;
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}
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int32_t Adafruit_BMP085::computeB5(int32_t UT) {
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int32_t X1 = (UT - (int32_t)ac6) * ((int32_t)ac5) >> 15;
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int32_t X2 = ((int32_t)mc << 11) / (X1 + (int32_t)md);
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return X1 + X2;
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}
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uint16_t Adafruit_BMP085::readRawTemperature(void) {
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write8(BMP085_CONTROL, BMP085_READTEMPCMD);
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delay(5);
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#if BMP085_DEBUG == 1
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Serial.print("Raw temp: ");
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Serial.println(read16(BMP085_TEMPDATA));
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#endif
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return read16(BMP085_TEMPDATA);
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}
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uint32_t Adafruit_BMP085::readRawPressure(void) {
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uint32_t raw;
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write8(BMP085_CONTROL, BMP085_READPRESSURECMD + (oversampling << 6));
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if (oversampling == BMP085_ULTRALOWPOWER)
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delay(5);
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else if (oversampling == BMP085_STANDARD)
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delay(8);
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else if (oversampling == BMP085_HIGHRES)
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delay(14);
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else
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delay(26);
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raw = read16(BMP085_PRESSUREDATA);
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raw <<= 8;
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raw |= read8(BMP085_PRESSUREDATA + 2);
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raw >>= (8 - oversampling);
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/* this pull broke stuff, look at it later?
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if (oversampling==0) {
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raw <<= 8;
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raw |= read8(BMP085_PRESSUREDATA+2);
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raw >>= (8 - oversampling);
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}
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*/
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#if BMP085_DEBUG == 1
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Serial.print("Raw pressure: ");
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Serial.println(raw);
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#endif
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return raw;
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}
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int32_t Adafruit_BMP085::readPressure(void) {
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int32_t UT, UP, B3, B5, B6, X1, X2, X3, p;
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uint32_t B4, B7;
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UT = readRawTemperature();
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UP = readRawPressure();
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#if BMP085_DEBUG == 1
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// use datasheet numbers!
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UT = 27898;
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UP = 23843;
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ac6 = 23153;
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ac5 = 32757;
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mc = -8711;
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md = 2868;
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b1 = 6190;
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b2 = 4;
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ac3 = -14383;
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ac2 = -72;
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ac1 = 408;
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ac4 = 32741;
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oversampling = 0;
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#endif
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B5 = computeB5(UT);
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#if BMP085_DEBUG == 1
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Serial.print("X1 = ");
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Serial.println(X1);
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Serial.print("X2 = ");
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Serial.println(X2);
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Serial.print("B5 = ");
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Serial.println(B5);
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#endif
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// do pressure calcs
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B6 = B5 - 4000;
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X1 = ((int32_t)b2 * ((B6 * B6) >> 12)) >> 11;
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X2 = ((int32_t)ac2 * B6) >> 11;
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X3 = X1 + X2;
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B3 = ((((int32_t)ac1 * 4 + X3) << oversampling) + 2) / 4;
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#if BMP085_DEBUG == 1
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Serial.print("B6 = ");
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Serial.println(B6);
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Serial.print("X1 = ");
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Serial.println(X1);
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Serial.print("X2 = ");
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Serial.println(X2);
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Serial.print("B3 = ");
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Serial.println(B3);
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#endif
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X1 = ((int32_t)ac3 * B6) >> 13;
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X2 = ((int32_t)b1 * ((B6 * B6) >> 12)) >> 16;
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X3 = ((X1 + X2) + 2) >> 2;
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B4 = ((uint32_t)ac4 * (uint32_t)(X3 + 32768)) >> 15;
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B7 = ((uint32_t)UP - B3) * (uint32_t)(50000UL >> oversampling);
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#if BMP085_DEBUG == 1
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Serial.print("X1 = ");
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Serial.println(X1);
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Serial.print("X2 = ");
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Serial.println(X2);
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Serial.print("B4 = ");
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Serial.println(B4);
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Serial.print("B7 = ");
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Serial.println(B7);
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#endif
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if (B7 < 0x80000000) {
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p = (B7 * 2) / B4;
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} else {
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p = (B7 / B4) * 2;
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}
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X1 = (p >> 8) * (p >> 8);
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X1 = (X1 * 3038) >> 16;
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X2 = (-7357 * p) >> 16;
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#if BMP085_DEBUG == 1
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Serial.print("p = ");
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Serial.println(p);
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Serial.print("X1 = ");
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Serial.println(X1);
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Serial.print("X2 = ");
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Serial.println(X2);
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#endif
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p = p + ((X1 + X2 + (int32_t)3791) >> 4);
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#if BMP085_DEBUG == 1
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Serial.print("p = ");
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Serial.println(p);
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#endif
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return p;
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}
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int32_t Adafruit_BMP085::readSealevelPressure(float altitude_meters) {
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float pressure = readPressure();
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return (int32_t)(pressure / pow(1.0 - altitude_meters / 44330, 5.255));
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}
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float Adafruit_BMP085::readTemperature(void) {
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int32_t UT, B5; // following ds convention
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float temp;
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UT = readRawTemperature();
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#if BMP085_DEBUG == 1
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// use datasheet numbers!
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UT = 27898;
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ac6 = 23153;
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ac5 = 32757;
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mc = -8711;
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md = 2868;
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#endif
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B5 = computeB5(UT);
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temp = (B5 + 8) >> 4;
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temp /= 10;
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return temp;
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}
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float Adafruit_BMP085::readAltitude(float sealevelPressure) {
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float altitude;
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float pressure = readPressure();
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altitude = 44330 * (1.0 - pow(pressure / sealevelPressure, 0.1903));
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return altitude;
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}
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/*********************************************************************/
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uint8_t Adafruit_BMP085::read8(uint8_t a) {
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uint8_t ret;
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// send 1 byte, reset i2c, read 1 byte
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i2c_dev->write_then_read(&a, 1, &ret, 1, true);
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return ret;
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}
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uint16_t Adafruit_BMP085::read16(uint8_t a) {
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uint8_t retbuf[2];
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uint16_t ret;
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// send 1 byte, reset i2c, read 2 bytes
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// we could typecast uint16_t as uint8_t array but would need to ensure proper
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// endianness
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i2c_dev->write_then_read(&a, 1, retbuf, 2, true);
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// write_then_read uses uint8_t array
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ret = retbuf[1] | (retbuf[0] << 8);
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return ret;
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}
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void Adafruit_BMP085::write8(uint8_t a, uint8_t d) {
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// send d prefixed with a (a d [stop])
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i2c_dev->write(&d, 1, true, &a, 1);
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}
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