-
Notifications
You must be signed in to change notification settings - Fork 3
/
BME280.cpp
165 lines (126 loc) · 5.65 KB
/
BME280.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
#include "Arduino.h"
#include <Wire.h>
#include "BME280.h"
BME280::BME280() {
}
void BME280::SetAltitudeAboveSeaLevel(int altitude) {
m_altitudeAboveSeaLevel = altitude;
}
bool BME280::TryInitialize(byte address) {
bool result = false;
m_address = address;
m_lastValue.Temperature = 1;
m_lastValue.Humidity = 2;
m_lastValue.Pressure = 3;
// BME280_REGISTER_CONTROLHUMID == ctrl_hum == 0xF2
// BME280_REGISTER_STATUS == status == 0xF3
// BME280_REGISTER_CONTROL == ctrl_meas == 0xF4
// BME280_REGISTER_CONFIG == config == 0xF5
//
#define OSRS_H BME280_OSRS_Hx01 // Oversampling Humidity - ctrl_hum
#define OSRS_P BME280_OSRS_Px01 // Oversampling Pressure - ctrl_meas (<< 2)
#define OSRS_T BME280_OSRS_Tx01 // Oversampling Temperature - ctrl_meas (<< 5)
#define T_SB BME280_T_SB_1000 // Standby setting - config (<< 5)
#define FILTER_COEF BME280_FILTER_COEF_4 // IIR Filter settings - config (<< 2)
if (Read8(BME280_REGISTER_CHIPID) == 0x60) {
ReadCompensation();
// Set Standby and IIR Filter
Write8(BME280_REGISTER_CONTROL, BME280_MODE_SLEEP);
Write8(BME280_REGISTER_CONFIG, ( (T_SB << 5) | (FILTER_COEF << 2) ));
// Set Oversampling and OpMode
Write8(BME280_REGISTER_CONTROLHUMID, OSRS_H); // Measurement starts in GetTemperature()
GetTemperature(); // GetTemperatue: MODE_FORCED, poll for Measurement finished
if (GetPressure() > 0) {
GetHumidity();
result = true;
}
}
return result;
}
void BME280::ReadCompensation() {
m_compensation.T1 = Read16_LE(BME280_REGISTER_T1);
m_compensation.T2 = ReadS16_LE(BME280_REGISTER_T2);
m_compensation.T3 = ReadS16_LE(BME280_REGISTER_T3);
m_compensation.P1 = Read16_LE(BME280_REGISTER_P1);
m_compensation.P2 = ReadS16_LE(BME280_REGISTER_P2);
m_compensation.P3 = ReadS16_LE(BME280_REGISTER_P3);
m_compensation.P4 = ReadS16_LE(BME280_REGISTER_P4);
m_compensation.P5 = ReadS16_LE(BME280_REGISTER_P5);
m_compensation.P6 = ReadS16_LE(BME280_REGISTER_P6);
m_compensation.P7 = ReadS16_LE(BME280_REGISTER_P7);
m_compensation.P8 = ReadS16_LE(BME280_REGISTER_P8);
m_compensation.P9 = ReadS16_LE(BME280_REGISTER_P9);
m_compensation.H1 = Read8(BME280_REGISTER_H1);
m_compensation.H2 = ReadS16_LE(BME280_REGISTER_H2);
m_compensation.H3 = Read8(BME280_REGISTER_H3);
m_compensation.H4 = (Read8(BME280_REGISTER_H4) << 4) | (Read8(BME280_REGISTER_H4 + 1) & 0xF);
m_compensation.H5 = (Read8(BME280_REGISTER_H5 + 1) << 4) | (Read8(BME280_REGISTER_H5) >> 4);
m_compensation.H6 = (int8_t)Read8(BME280_REGISTER_H6);
}
bme280_compensation BME280::GetCompensationValues() {
return m_compensation;
}
BME280Value BME280::GetLastMeasuredValue() {
return m_lastValue;
}
float BME280::GetTemperature() {
int32_t var1, var2;
// measurement time
#define T_MEASURE ( 1 + (2 * (OSRS_T)) + (2 * (OSRS_P)) + (2 * (OSRS_H)))
Write8(BME280_REGISTER_CONTROL, ( (OSRS_T << 5) | (OSRS_P << 2) | BME280_MODE_FORCED ));
do {
delay(1); // 1ms delay
} while ((1 << 3) & Read8(BME280_REGISTER_STATUS)); // until measurement finished
int32_t adc_T = Read16(BME280_REGISTER_TEMPDATA);
adc_T <<= 8;
adc_T |= Read8(BME280_REGISTER_TEMPDATA + 2);
adc_T >>= 4;
m_lastValue.ADCT = adc_T;
var1 = ((((adc_T >> 3) - ((int32_t)m_compensation.T1 << 1))) * ((int32_t)m_compensation.T2)) >> 11;
var2 = (((((adc_T >> 4) - ((int32_t)m_compensation.T1)) * ((adc_T >> 4) - ((int32_t)m_compensation.T1))) >> 12) * ((int32_t)m_compensation.T3)) >> 14;
m_compensatedTemperature = var1 + var2;
float T = (m_compensatedTemperature * 5 + 128) >> 8;
m_lastValue.Temperature = T / 100.0; // 2 digits precision
T = round(T / 10) / 10.0;
return T;
}
float BME280::GetPressure() {
int64_t var1, var2, p;
int32_t adc_P = Read16(BME280_REGISTER_PRESSUREDATA);
adc_P <<= 8;
adc_P |= Read8(BME280_REGISTER_PRESSUREDATA+2);
adc_P >>= 4;
m_lastValue.ADCP = adc_P;
var1 = ((int64_t)m_compensatedTemperature) - 128000;
var2 = var1 * var1 * (int64_t)m_compensation.P6;
var2 = var2 + ((var1*(int64_t)m_compensation.P5) << 17);
var2 = var2 + (((int64_t)m_compensation.P4) << 35);
var1 = ((var1 * var1 * (int64_t)m_compensation.P3) >> 8) + ((var1 * (int64_t)m_compensation.P2) << 12);
var1 = (((((int64_t)1) << 47) + var1))*((int64_t)m_compensation.P1) >> 33;
if (var1 == 0) {
return 0;
}
p = 1048576 - adc_P;
p = (((p<<31) - var2)*3125) / var1;
var1 = (((int64_t)m_compensation.P9) * (p >> 13) * (p >> 13)) >> 25;
var2 = (((int64_t)m_compensation.P8) * p) >> 19;
p = ((p + var1 + var2) >> 8) + (((int64_t)m_compensation.P7) << 4);
p = (float)p / 256;
p /= pow(((float) 1.0 - ((float)m_altitudeAboveSeaLevel / 44330.0)), (float) 5.255);
p /= 10.0;
m_lastValue.Pressure = (float)p / 10.0;
return m_lastValue.Pressure;
}
int BME280::GetHumidity() {
int32_t adc_H = Read16(BME280_REGISTER_HUMIDDATA);
m_lastValue.ADCH = adc_H;
int32_t v_x1_u32r;
v_x1_u32r = (m_compensatedTemperature - ((int32_t)76800));
v_x1_u32r = (((((adc_H << 14) - (((int32_t)m_compensation.H4) << 20) - (((int32_t)m_compensation.H5) * v_x1_u32r)) + ((int32_t)16384)) >> 15) * (((((((v_x1_u32r * ((int32_t)m_compensation.H6)) >> 10) * (((v_x1_u32r * ((int32_t)m_compensation.H3)) >> 11) + ((int32_t)32768))) >> 10) + ((int32_t)2097152)) * ((int32_t)m_compensation.H2) + 8192) >> 14));
v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) * ((int32_t)m_compensation.H1)) >> 4));
v_x1_u32r = (v_x1_u32r < 0) ? 0 : v_x1_u32r;
v_x1_u32r = (v_x1_u32r > 419430400) ? 419430400 : v_x1_u32r;
float h = (v_x1_u32r>>12);
m_lastValue.Humidity = h / 1024;
return m_lastValue.Humidity;
}