Samir Bouaziz
/
test_bmp085
test capteurs BMP085 météo
Diff: BMP085_sam.cpp
- Revision:
- 0:ad2afb285975
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/BMP085_sam.cpp Fri Oct 14 18:44:39 2011 +0000 @@ -0,0 +1,152 @@ +/* + * mbed library to use a Bosch Sensortec BMP085 sensor + * Copyright (c) 2010 Hiroshi Suga + * Released under the MIT License: http://mbed.org/license/mit + */ + + /** @file BMP085.cpp + * @brief mbed library to use a Bosch Sensortec BMP085 sensor + * barometric pressure sensor BMP085 (Bosch Sensortec) + * interface: I2C digital + */ + + #include "mbed.h" + #include "BMP085.h" + + #define WEATHER_BMP085 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 + */ + BMP085::BMP085 (PinName p_sda, PinName p_scl, BMP085_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 + */ + BMP085::BMP085 (I2C& p_i2c, BMP085_oss p_oss) : i2c(p_i2c) { + init(p_oss); + } + + /** + * @brief Get temperature + * @return temperature (`C) + */ + float BMP085::get_temperature() { + return temperature; + } + + /** + * @brief Get pressure + * @return pressure (hPa) + */ + float BMP085::get_pressure() { + return pressure; + } + + /** + * @brief Update results + */ + void BMP085::update () { + long t, p, ut, up, x1, x2, x3, b3, b5, b6; + unsigned long b4, b7; + + twi_writechar(WEATHER_BMP085, 0xf4, 0x2e); + wait(0.01); + ut = twi_readshort(WEATHER_BMP085, 0xf6); + + twi_writechar(WEATHER_BMP085, 0xf4, 0x34 | (oss << 6)); + wait(0.05); + up = twi_readlong(WEATHER_BMP085, 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 BMP085::init (BMP085_oss p_oss) { + ac1 = twi_readshort(WEATHER_BMP085, 0xaa); + ac2 = twi_readshort(WEATHER_BMP085, 0xac); + ac3 = twi_readshort(WEATHER_BMP085, 0xae); + ac4 = twi_readshort(WEATHER_BMP085, 0xb0); + ac5 = twi_readshort(WEATHER_BMP085, 0xb2); + ac6 = twi_readshort(WEATHER_BMP085, 0xb4); + b1 = twi_readshort(WEATHER_BMP085, 0xb6); + b2 = twi_readshort(WEATHER_BMP085, 0xb8); + mb = twi_readshort(WEATHER_BMP085, 0xba); + mc = twi_readshort(WEATHER_BMP085, 0xbc); + md = twi_readshort(WEATHER_BMP085, 0xbe); + oss = p_oss; + } + + unsigned short BMP085::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 BMP085::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 BMP085::twi_writechar (int id, int addr, int dat) { + + i2c.start(); + i2c.write(id); + i2c.write(addr); + i2c.write(dat); + i2c.stop(); + } \ No newline at end of file