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Dependencies:   Servo mbed

Fork of mbed_droptest by Soyoon Kim

Barometer.cpp@4:62aec4ae9f67, 2016-08-01 (annotated)

Committer:
skyyoungsik
Date:
Mon Aug 01 09:29:24 2016 +0000
Revision:
4:62aec4ae9f67
Parent:
0:6ac6b2d2bf1a 
resistry

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Soyoon 0:6ac6b2d2bf1a 1 #include "mbed.h"
Soyoon 0:6ac6b2d2bf1a 2 #include "Barometer.h"
Soyoon 0:6ac6b2d2bf1a 3
Soyoon 0:6ac6b2d2bf1a 4 #define WEATHER_Barometer 0xee
Soyoon 0:6ac6b2d2bf1a 5 #define xpow(x, y) ((long)1 << y)
Soyoon 0:6ac6b2d2bf1a 6
Soyoon 0:6ac6b2d2bf1a 7
Soyoon 0:6ac6b2d2bf1a 8 Barometer::Barometer (PinName p_sda, PinName p_scl, Barometer_oss p_oss) : i2c(p_sda, p_scl) {
Soyoon 0:6ac6b2d2bf1a 9 init(p_oss);
Soyoon 0:6ac6b2d2bf1a 10 }
Soyoon 0:6ac6b2d2bf1a 11
Soyoon 0:6ac6b2d2bf1a 12 Barometer::Barometer (I2C& p_i2c, Barometer_oss p_oss) : i2c(p_i2c) {
Soyoon 0:6ac6b2d2bf1a 13 init(p_oss);
Soyoon 0:6ac6b2d2bf1a 14 }
Soyoon 0:6ac6b2d2bf1a 15
Soyoon 0:6ac6b2d2bf1a 16
Soyoon 0:6ac6b2d2bf1a 17 float Barometer::get_temperature() {
Soyoon 0:6ac6b2d2bf1a 18 return temperature;
Soyoon 0:6ac6b2d2bf1a 19 }
Soyoon 0:6ac6b2d2bf1a 20
Soyoon 0:6ac6b2d2bf1a 21 float Barometer::get_pressure() {
Soyoon 0:6ac6b2d2bf1a 22 return pressure;
Soyoon 0:6ac6b2d2bf1a 23 }
Soyoon 0:6ac6b2d2bf1a 24
Soyoon 0:6ac6b2d2bf1a 25 float Barometer::get_altitude_m() {
Soyoon 0:6ac6b2d2bf1a 26 altitude = 44330*(1-pow((pressure/1013.25),(0.190295)));
Soyoon 0:6ac6b2d2bf1a 27 return altitude;
Soyoon 0:6ac6b2d2bf1a 28 }
Soyoon 0:6ac6b2d2bf1a 29
Soyoon 0:6ac6b2d2bf1a 30 void Barometer::update () {
Soyoon 0:6ac6b2d2bf1a 31 long t, p, ut, up, x1, x2, x3, b3, b5, b6;
Soyoon 0:6ac6b2d2bf1a 32 unsigned long b4, b7;
Soyoon 0:6ac6b2d2bf1a 33
Soyoon 0:6ac6b2d2bf1a 34 twi_writechar(WEATHER_Barometer, 0xf4, 0x2e);
Soyoon 0:6ac6b2d2bf1a 35 wait(0.01);
Soyoon 0:6ac6b2d2bf1a 36 ut = twi_readshort(WEATHER_Barometer, 0xf6);
Soyoon 0:6ac6b2d2bf1a 37
Soyoon 0:6ac6b2d2bf1a 38 twi_writechar(WEATHER_Barometer, 0xf4, 0x34 | (oss << 6));
Soyoon 0:6ac6b2d2bf1a 39 wait(0.05);
Soyoon 0:6ac6b2d2bf1a 40 up = twi_readlong(WEATHER_Barometer, 0xf6) >> (8 - oss);
Soyoon 0:6ac6b2d2bf1a 41
Soyoon 0:6ac6b2d2bf1a 42 x1 = (ut - ac6) * ac5 / xpow(2, 15);
Soyoon 0:6ac6b2d2bf1a 43 x2 = (long)mc * xpow(2, 11) / (x1 + md);
Soyoon 0:6ac6b2d2bf1a 44 b5 = x1 + x2;
Soyoon 0:6ac6b2d2bf1a 45 t = (b5 + 8) / xpow(2, 4);
Soyoon 0:6ac6b2d2bf1a 46 temperature = (float)t / 10.0;
Soyoon 0:6ac6b2d2bf1a 47
Soyoon 0:6ac6b2d2bf1a 48 b6 = b5 - 4000;
Soyoon 0:6ac6b2d2bf1a 49 x1 = (b2 * (b6 * b6 / xpow(2, 12))) / xpow(2, 11);
Soyoon 0:6ac6b2d2bf1a 50 x2 = ac2 * b6 / xpow(2, 11);
Soyoon 0:6ac6b2d2bf1a 51 x3 = x1 + x2;
Soyoon 0:6ac6b2d2bf1a 52 b3 = ((((unsigned long)ac1 * 4 + x3) << oss) + 2) / 4;
Soyoon 0:6ac6b2d2bf1a 53 x1 = ac3 * b6 / xpow(2, 13);
Soyoon 0:6ac6b2d2bf1a 54 x2 = (b1 * (b6 * b6 / xpow(2, 12))) / xpow(2, 16);
Soyoon 0:6ac6b2d2bf1a 55 x3 = ((x1 + x2) + 2) / xpow(2, 2);
Soyoon 0:6ac6b2d2bf1a 56 b4 = ac4 * (unsigned long)(x3 + 32768) / xpow(2, 15);
Soyoon 0:6ac6b2d2bf1a 57 b7 = ((unsigned long)up - b3) * (50000 >> oss);
Soyoon 0:6ac6b2d2bf1a 58 if (b7 < (unsigned long)0x80000000) {
Soyoon 0:6ac6b2d2bf1a 59 p = (b7 * 2) / b4;
Soyoon 0:6ac6b2d2bf1a 60 } else {
Soyoon 0:6ac6b2d2bf1a 61 p = (b7 / b4) * 2;
Soyoon 0:6ac6b2d2bf1a 62 }
Soyoon 0:6ac6b2d2bf1a 63 x1 = (p / xpow(2, 8)) * (p / xpow(2, 8));
Soyoon 0:6ac6b2d2bf1a 64 x1 = (x1 * 3038) / xpow(2, 16);
Soyoon 0:6ac6b2d2bf1a 65 x2 = (-7357 * p) / xpow(2, 16);
Soyoon 0:6ac6b2d2bf1a 66 p = p + (x1 + x2 + 3791) / xpow(2, 4);
Soyoon 0:6ac6b2d2bf1a 67 pressure = (float)p / 100.0;
Soyoon 0:6ac6b2d2bf1a 68 }
Soyoon 0:6ac6b2d2bf1a 69
Soyoon 0:6ac6b2d2bf1a 70 void Barometer::init (Barometer_oss p_oss) {
Soyoon 0:6ac6b2d2bf1a 71 ac1 = twi_readshort(WEATHER_Barometer, 0xaa);
Soyoon 0:6ac6b2d2bf1a 72 ac2 = twi_readshort(WEATHER_Barometer, 0xac);
Soyoon 0:6ac6b2d2bf1a 73 ac3 = twi_readshort(WEATHER_Barometer, 0xae);
Soyoon 0:6ac6b2d2bf1a 74 ac4 = twi_readshort(WEATHER_Barometer, 0xb0);
Soyoon 0:6ac6b2d2bf1a 75 ac5 = twi_readshort(WEATHER_Barometer, 0xb2);
Soyoon 0:6ac6b2d2bf1a 76 ac6 = twi_readshort(WEATHER_Barometer, 0xb4);
Soyoon 0:6ac6b2d2bf1a 77 b1 = twi_readshort(WEATHER_Barometer, 0xb6);
Soyoon 0:6ac6b2d2bf1a 78 b2 = twi_readshort(WEATHER_Barometer, 0xb8);
Soyoon 0:6ac6b2d2bf1a 79 mb = twi_readshort(WEATHER_Barometer, 0xba);
Soyoon 0:6ac6b2d2bf1a 80 mc = twi_readshort(WEATHER_Barometer, 0xbc);
Soyoon 0:6ac6b2d2bf1a 81 md = twi_readshort(WEATHER_Barometer, 0xbe);
Soyoon 0:6ac6b2d2bf1a 82 oss = p_oss;
Soyoon 0:6ac6b2d2bf1a 83 }
Soyoon 0:6ac6b2d2bf1a 84
Soyoon 0:6ac6b2d2bf1a 85 unsigned short Barometer::twi_readshort (int id, int addr) {
Soyoon 0:6ac6b2d2bf1a 86 unsigned short i;
Soyoon 0:6ac6b2d2bf1a 87
Soyoon 0:6ac6b2d2bf1a 88 i2c.start();
Soyoon 0:6ac6b2d2bf1a 89 i2c.write(id);
Soyoon 0:6ac6b2d2bf1a 90 i2c.write(addr);
Soyoon 0:6ac6b2d2bf1a 91
Soyoon 0:6ac6b2d2bf1a 92 i2c.start();
Soyoon 0:6ac6b2d2bf1a 93 i2c.write(id | 1);
Soyoon 0:6ac6b2d2bf1a 94 i = i2c.read(1) << 8;
Soyoon 0:6ac6b2d2bf1a 95 i |= i2c.read(0);
Soyoon 0:6ac6b2d2bf1a 96 i2c.stop();
Soyoon 0:6ac6b2d2bf1a 97
Soyoon 0:6ac6b2d2bf1a 98 return i;
Soyoon 0:6ac6b2d2bf1a 99 }
Soyoon 0:6ac6b2d2bf1a 100
Soyoon 0:6ac6b2d2bf1a 101 unsigned long Barometer::twi_readlong (int id, int addr) {
Soyoon 0:6ac6b2d2bf1a 102 unsigned long i;
Soyoon 0:6ac6b2d2bf1a 103
Soyoon 0:6ac6b2d2bf1a 104 i2c.start();
Soyoon 0:6ac6b2d2bf1a 105 i2c.write(id);
Soyoon 0:6ac6b2d2bf1a 106 i2c.write(addr);
Soyoon 0:6ac6b2d2bf1a 107
Soyoon 0:6ac6b2d2bf1a 108 i2c.start();
Soyoon 0:6ac6b2d2bf1a 109 i2c.write(id | 1);
Soyoon 0:6ac6b2d2bf1a 110 i = i2c.read(1) << 16;
Soyoon 0:6ac6b2d2bf1a 111 i |= i2c.read(1) << 8;
Soyoon 0:6ac6b2d2bf1a 112 i |= i2c.read(0);
Soyoon 0:6ac6b2d2bf1a 113 i2c.stop();
Soyoon 0:6ac6b2d2bf1a 114
Soyoon 0:6ac6b2d2bf1a 115 return i;
Soyoon 0:6ac6b2d2bf1a 116 }
Soyoon 0:6ac6b2d2bf1a 117
Soyoon 0:6ac6b2d2bf1a 118 void Barometer::twi_writechar (int id, int addr, int dat) {
Soyoon 0:6ac6b2d2bf1a 119
Soyoon 0:6ac6b2d2bf1a 120 i2c.start();
Soyoon 0:6ac6b2d2bf1a 121 i2c.write(id);
Soyoon 0:6ac6b2d2bf1a 122 i2c.write(addr);
Soyoon 0:6ac6b2d2bf1a 123 i2c.write(dat);
Soyoon 0:6ac6b2d2bf1a 124 i2c.stop();
Soyoon 0:6ac6b2d2bf1a 125 }