baro
Diff: MS5611.cpp
- Revision:
- 0:669dfadf96c5
diff -r 000000000000 -r 669dfadf96c5 MS5611.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MS5611.cpp Sat Dec 14 04:19:18 2013 +0000 @@ -0,0 +1,152 @@ +/* + * 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::get_temperature() { + return temperature; +} + +/** + * @brief Get pressure + * @return pressure (hPa) + */ +float MS5611::get_pressure() { + 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(); +}