baro
Fork of MS5611 by
MS5611.cpp
- Committer:
- hiltontnunay
- Date:
- 2014-01-17
- Revision:
- 1:8ebf0430f788
- Parent:
- 0:669dfadf96c5
File content as of revision 1:8ebf0430f788:
/* * mbed library to use a Bosch Sensortec MS5611 sensor * Copyright (c) 2010 Hiroshi Suga * Released under the MIT License: http://mbed.org/license/mit */ /** @file MS5611.cpp * @brief mbed library to use a Bosch Sensortec MS5611 sensor * barometric pressure sensor MS5611 (Bosch Sensortec) * interface: I2C digital */ #include "mbed.h" #include "MS5611.h" #define WEATHER_MS5611 0xee #define xpow(x, y) ((long)1 << y) /** * @brief Initializes interface (private I2C) * @param p_sda port of I2C SDA * @param p_scl port of I2C SCL * @param p_oss parameter of OSS */ MS5611::MS5611 (PinName p_sda, PinName p_scl, MS5611_oss p_oss) : i2c(p_sda, p_scl) { init(p_oss); } /** * @brief Initializes interface (public I2C) * @param p_i2c instance of I2C class * @param p_oss parameter of OSS */ MS5611::MS5611 (I2C& p_i2c, MS5611_oss p_oss) : i2c(p_i2c) { init(p_oss); } /** * @brief Get temperature * @return temperature (`C) */ float MS5611::getTemperature() { return temperature; } /** * @brief Get pressure * @return pressure (hPa) */ float MS5611::getPressure() { return pressure; } /** * @brief Update results */ void MS5611::update () { long t, p, ut, up, x1, x2, x3, b3, b5, b6; unsigned long b4, b7; twi_writechar(WEATHER_MS5611, 0xf4, 0x2e); wait(0.0045); //wait(0.01); ut = twi_readshort(WEATHER_MS5611, 0xf6); twi_writechar(WEATHER_MS5611, 0xf4, 0x34 | (oss << 6)); wait(0.0045); //wait(0.05); up = twi_readlong(WEATHER_MS5611, 0xf6) >> (8 - oss); x1 = (ut - ac6) * ac5 / xpow(2, 15); x2 = (long)mc * xpow(2, 11) / (x1 + md); b5 = x1 + x2; t = (b5 + 8) / xpow(2, 4); temperature = (float)t / 10.0; b6 = b5 - 4000; x1 = (b2 * (b6 * b6 / xpow(2, 12))) / xpow(2, 11); x2 = ac2 * b6 / xpow(2, 11); x3 = x1 + x2; b3 = ((((unsigned long)ac1 * 4 + x3) << oss) + 2) / 4; x1 = ac3 * b6 / xpow(2, 13); x2 = (b1 * (b6 * b6 / xpow(2, 12))) / xpow(2, 16); x3 = ((x1 + x2) + 2) / xpow(2, 2); b4 = ac4 * (unsigned long)(x3 + 32768) / xpow(2, 15); b7 = ((unsigned long)up - b3) * (50000 >> oss); if (b7 < (unsigned long)0x80000000) { p = (b7 * 2) / b4; } else { p = (b7 / b4) * 2; } x1 = (p / xpow(2, 8)) * (p / xpow(2, 8)); x1 = (x1 * 3038) / xpow(2, 16); x2 = (-7357 * p) / xpow(2, 16); p = p + (x1 + x2 + 3791) / xpow(2, 4); pressure = (float)p / 100.0; } void MS5611::init (MS5611_oss p_oss) { ac1 = twi_readshort(WEATHER_MS5611, 0xaa); ac2 = twi_readshort(WEATHER_MS5611, 0xac); ac3 = twi_readshort(WEATHER_MS5611, 0xae); ac4 = twi_readshort(WEATHER_MS5611, 0xb0); ac5 = twi_readshort(WEATHER_MS5611, 0xb2); ac6 = twi_readshort(WEATHER_MS5611, 0xb4); b1 = twi_readshort(WEATHER_MS5611, 0xb6); b2 = twi_readshort(WEATHER_MS5611, 0xb8); mb = twi_readshort(WEATHER_MS5611, 0xba); mc = twi_readshort(WEATHER_MS5611, 0xbc); md = twi_readshort(WEATHER_MS5611, 0xbe); oss = p_oss; } unsigned short MS5611::twi_readshort (int id, int addr) { unsigned short i; i2c.start(); i2c.write(id); i2c.write(addr); i2c.start(); i2c.write(id | 1); i = i2c.read(1) << 8; i |= i2c.read(0); i2c.stop(); return i; } unsigned long MS5611::twi_readlong (int id, int addr) { unsigned long i; i2c.start(); i2c.write(id); i2c.write(addr); i2c.start(); i2c.write(id | 1); i = i2c.read(1) << 16; i |= i2c.read(1) << 8; i |= i2c.read(0); i2c.stop(); return i; } void MS5611::twi_writechar (int id, int addr, int dat) { i2c.start(); i2c.write(id); i2c.write(addr); i2c.write(dat); i2c.stop(); }