1 /*
2 * Author: Yevgeniy Kiveisha <yevgeniy.kiveisha@intel.com>
3 * Copyright (c) 2014 Intel Corporation.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining
6 * a copy of this software and associated documentation files (the
7 * "Software"), to deal in the Software without restriction, including
8 * without limitation the rights to use, copy, modify, merge, publish,
9 * distribute, sublicense, and/or sell copies of the Software, and to
10 * permit persons to whom the Software is furnished to do so, subject to
11 * the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be
14 * included in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 */
24
25 #include <iostream>
26 #include <string>
27 #include <stdexcept>
28 #include <unistd.h>
29 #include <stdlib.h>
30
31 #include "bmpx8x.h"
32
33 using namespace upm;
34
BMPX8X(int bus,int devAddr,uint8_t mode)35 BMPX8X::BMPX8X (int bus, int devAddr, uint8_t mode) : m_controlAddr(devAddr), m_i2ControlCtx(bus) {
36
37 m_name = "BMPX8X";
38
39 mraa::Result ret = m_i2ControlCtx.address(m_controlAddr);
40 if (ret != mraa::SUCCESS) {
41 throw std::invalid_argument(std::string(__FUNCTION__) +
42 ": mraa_i2c_address() failed");
43 return;
44 }
45
46 if (i2cReadReg_8 (0xD0) != 0x55) {
47 throw std::runtime_error(std::string(__FUNCTION__) +
48 ": Invalid chip ID");
49 return;
50 }
51
52 if (mode > BMP085_ULTRAHIGHRES) {
53 mode = BMP085_ULTRAHIGHRES;
54 }
55 oversampling = mode;
56
57 /* read calibration data */
58 ac1 = i2cReadReg_16 (BMP085_CAL_AC1);
59 ac2 = i2cReadReg_16 (BMP085_CAL_AC2);
60 ac3 = i2cReadReg_16 (BMP085_CAL_AC3);
61 ac4 = i2cReadReg_16 (BMP085_CAL_AC4);
62 ac5 = i2cReadReg_16 (BMP085_CAL_AC5);
63 ac6 = i2cReadReg_16 (BMP085_CAL_AC6);
64
65 b1 = i2cReadReg_16 (BMP085_CAL_B1);
66 b2 = i2cReadReg_16 (BMP085_CAL_B2);
67
68 mb = i2cReadReg_16 (BMP085_CAL_MB);
69 mc = i2cReadReg_16 (BMP085_CAL_MC);
70 md = i2cReadReg_16 (BMP085_CAL_MD);
71 }
72
73 int32_t
getPressure()74 BMPX8X::getPressure () {
75 int32_t UT, UP, B3, B5, B6, X1, X2, X3, p;
76 uint32_t B4, B7;
77
78 UT = getTemperatureRaw();
79 UP = getPressureRaw();
80 B5 = computeB5(UT);
81
82 // do pressure calcs
83 B6 = B5 - 4000;
84 X1 = ((int32_t)b2 * ( (B6 * B6)>>12 )) >> 11;
85 X2 = ((int32_t)ac2 * B6) >> 11;
86 X3 = X1 + X2;
87 B3 = ((((int32_t)ac1*4 + X3) << oversampling) + 2) / 4;
88
89 X1 = ((int32_t)ac3 * B6) >> 13;
90 X2 = ((int32_t)b1 * ((B6 * B6) >> 12)) >> 16;
91 X3 = ((X1 + X2) + 2) >> 2;
92 B4 = ((uint32_t)ac4 * (uint32_t)(X3 + 32768)) >> 15;
93 B7 = ((uint32_t)UP - B3) * (uint32_t)( 50000UL >> oversampling );
94
95 if (B7 < 0x80000000) {
96 p = (B7 * 2) / B4;
97 } else {
98 p = (B7 / B4) * 2;
99 }
100 X1 = (p >> 8) * (p >> 8);
101 X1 = (X1 * 3038) >> 16;
102 X2 = (-7357 * p) >> 16;
103
104 p = p + ((X1 + X2 + (int32_t)3791)>>4);
105
106 return p;
107 }
108
109 int32_t
getPressureRaw()110 BMPX8X::getPressureRaw () {
111 uint32_t raw;
112
113 i2cWriteReg (BMP085_CONTROL, BMP085_READPRESSURECMD + (oversampling << 6));
114
115 if (oversampling == BMP085_ULTRALOWPOWER) {
116 usleep(5000);
117 } else if (oversampling == BMP085_STANDARD) {
118 usleep(8000);
119 } else if (oversampling == BMP085_HIGHRES) {
120 usleep(14000);
121 } else {
122 usleep(26000);
123 }
124
125 raw = i2cReadReg_16 (BMP085_PRESSUREDATA);
126
127 raw <<= 8;
128 raw |= i2cReadReg_8 (BMP085_PRESSUREDATA + 2);
129 raw >>= (8 - oversampling);
130
131 return raw;
132 }
133
134 int16_t
getTemperatureRaw()135 BMPX8X::getTemperatureRaw () {
136 i2cWriteReg (BMP085_CONTROL, BMP085_READTEMPCMD);
137 usleep(5000);
138 return i2cReadReg_16 (BMP085_TEMPDATA);
139 }
140
141 float
getTemperature()142 BMPX8X::getTemperature () {
143 int32_t UT, B5; // following ds convention
144 float temp;
145
146 UT = getTemperatureRaw ();
147
148 B5 = computeB5 (UT);
149 temp = (B5 + 8) >> 4;
150 temp /= 10;
151
152 return temp;
153 }
154
155 int32_t
getSealevelPressure(float altitudeMeters)156 BMPX8X::getSealevelPressure(float altitudeMeters) {
157 float pressure = getPressure ();
158 return (int32_t)(pressure / pow(1.0-altitudeMeters/44330, 5.255));
159 }
160
161 float
getAltitude(float sealevelPressure)162 BMPX8X::getAltitude (float sealevelPressure) {
163 float altitude;
164
165 float pressure = getPressure ();
166
167 altitude = 44330 * (1.0 - pow(pressure /sealevelPressure,0.1903));
168
169 return altitude;
170 }
171
172 int32_t
computeB5(int32_t UT)173 BMPX8X::computeB5(int32_t UT) {
174 int32_t X1 = (UT - (int32_t)ac6) * ((int32_t)ac5) >> 15;
175 int32_t X2 = ((int32_t)mc << 11) / (X1+(int32_t)md);
176
177 return X1 + X2;
178 }
179
180 mraa::Result
i2cWriteReg(uint8_t reg,uint8_t value)181 BMPX8X::i2cWriteReg (uint8_t reg, uint8_t value) {
182 mraa::Result error = mraa::SUCCESS;
183
184 uint8_t data[2] = { reg, value };
185 error = m_i2ControlCtx.address (m_controlAddr);
186 error = m_i2ControlCtx.write (data, 2);
187
188 return error;
189 }
190
191 uint16_t
i2cReadReg_16(int reg)192 BMPX8X::i2cReadReg_16 (int reg) {
193 uint16_t data;
194
195 m_i2ControlCtx.address(m_controlAddr);
196 m_i2ControlCtx.writeByte(reg);
197
198 m_i2ControlCtx.address(m_controlAddr);
199 m_i2ControlCtx.read((uint8_t *)&data, 0x2);
200
201 uint8_t high = (data & 0xFF00) >> 8;
202 data = (data << 8) & 0xFF00;
203 data |= high;
204
205 return data;
206 }
207
208 uint8_t
i2cReadReg_8(int reg)209 BMPX8X::i2cReadReg_8 (int reg) {
210 uint8_t data;
211
212 m_i2ControlCtx.address(m_controlAddr);
213 m_i2ControlCtx.writeByte(reg);
214
215 m_i2ControlCtx.address(m_controlAddr);
216 m_i2ControlCtx.read(&data, 0x1);
217
218 return data;
219 }
220