1 /*
2 * Author: Mihai Tudor Panu <mihai.tudor.panu@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 "math.h"
30 #include "adxl345.h"
31
32 #define READ_BUFFER_LENGTH 6
33
34 //address and id
35 #define ADXL345_I2C_ADDR 0x53
36 #define ADXL345_ID 0x00
37
38 //control registers
39 #define ADXL345_OFSX 0x1E
40 #define ADXL345_OFSY 0x1F
41 #define ADXL345_OFSZ 0x20
42 #define ADXL345_TAP_THRESH 0x1D
43 #define ADXL345_TAP_DUR 0x21
44 #define ADXL345_TAP_LATENCY 0x22
45 #define ADXL345_ACT_THRESH 0x24
46 #define ADXL345_INACT_THRESH 0x25
47 #define ADXL345_INACT_TIME 0x26
48 #define ADXL345_INACT_ACT_CTL 0x27
49 #define ADXL345_FALL_THRESH 0x28
50 #define ADXL345_FALL_TIME 0x29
51 #define ADXL345_TAP_AXES 0x2A
52 #define ADXL345_ACT_TAP_STATUS 0x2B
53
54 //interrupt registers
55 #define ADXL345_INT_ENABLE 0x2E
56 #define ADXL345_INT_MAP 0x2F
57 #define ADXL345_INT_SOURCE 0x30
58
59 //data registers (read only)
60 #define ADXL345_XOUT_L 0x32
61 #define ADXL345_XOUT_H 0x33
62 #define ADXL345_YOUT_L 0x34
63 #define ADXL345_YOUT_H 0x35
64 #define ADXL345_ZOUT_L 0x36
65 #define ADXL345_ZOUT_H 0x37
66 #define DATA_REG_SIZE 6
67
68 //data and power management
69 #define ADXL345_BW_RATE 0x2C
70 #define ADXL345_POWER_CTL 0x2D
71 #define ADXL345_DATA_FORMAT 0x31
72 #define ADXL345_FIFO_CTL 0x38
73 #define ADXL345_FIFO_STATUS 0x39
74
75 //useful values
76 #define ADXL345_POWER_ON 0x08
77 #define ADXL345_AUTO_SLP 0x30
78 #define ADXL345_STANDBY 0x00
79
80 //scales and resolution
81 #define ADXL345_FULL_RES 0x08
82 #define ADXL345_10BIT 0x00
83 #define ADXL345_2G 0x00
84 #define ADXL345_4G 0x01
85 #define ADXL345_8G 0x02
86 #define ADXL345_16G 0x03
87
88 using namespace upm;
89
Adxl345(int bus)90 Adxl345::Adxl345(int bus) : m_i2c(bus)
91 {
92 //init bus and reset chip
93 if ( m_i2c.address(ADXL345_I2C_ADDR) != mraa::SUCCESS ){
94 throw std::invalid_argument(std::string(__FUNCTION__) +
95 ": i2c.address() failed");
96 return;
97 }
98
99 m_buffer[0] = ADXL345_POWER_CTL;
100 m_buffer[1] = ADXL345_POWER_ON;
101 if( m_i2c.write(m_buffer, 2) != mraa::SUCCESS){
102 throw std::runtime_error(std::string(__FUNCTION__) +
103 ": i2c.write() control register failed");
104 return;
105 }
106
107 if ( m_i2c.address(ADXL345_I2C_ADDR) != mraa::SUCCESS ){
108 throw std::invalid_argument(std::string(__FUNCTION__) +
109 ": i2c.address() failed");
110 return;
111 }
112
113 m_buffer[0] = ADXL345_DATA_FORMAT;
114 m_buffer[1] = ADXL345_16G | ADXL345_FULL_RES;
115 if( m_i2c.write(m_buffer, 2) != mraa::SUCCESS){
116 throw std::runtime_error(std::string(__FUNCTION__) +
117 ": i2c.write() mode register failed");
118 return;
119 }
120
121 //2.5V sensitivity is 256 LSB/g = 0.00390625 g/bit
122 //3.3V x and y sensitivity is 265 LSB/g = 0.003773584 g/bit, z is the same
123
124 m_offsets[0] = 0.003773584;
125 m_offsets[1] = 0.003773584;
126 m_offsets[2] = 0.00390625;
127
128 Adxl345::update();
129 }
130
131 float*
getAcceleration()132 Adxl345::getAcceleration()
133 {
134 for(int i = 0; i < 3; i++){
135 m_accel[i] = m_rawaccel[i] * m_offsets[i];
136 }
137 return &m_accel[0];
138 }
139
140 int16_t*
getRawValues()141 Adxl345::getRawValues()
142 {
143 return &m_rawaccel[0];
144 }
145
146 uint8_t
getScale()147 Adxl345::getScale(){
148
149 uint8_t result;
150
151 m_i2c.address(ADXL345_I2C_ADDR);
152 m_i2c.writeByte(ADXL345_DATA_FORMAT);
153
154 m_i2c.address(ADXL345_I2C_ADDR);
155 result = m_i2c.readByte();
156
157 return pow(2, (result & 0x03) + 1);
158 }
159
160 mraa::Result
update(void)161 Adxl345::update(void)
162 {
163 m_i2c.address(ADXL345_I2C_ADDR);
164 m_i2c.writeByte(ADXL345_XOUT_L);
165
166 m_i2c.address(ADXL345_I2C_ADDR);
167 m_i2c.read(m_buffer, DATA_REG_SIZE);
168
169 // x
170 m_rawaccel[0] = ((m_buffer[1] << 8 ) | m_buffer[0]);
171 // y
172 m_rawaccel[1] = ((m_buffer[3] << 8 ) | m_buffer[2]);
173 // z
174 m_rawaccel[2] = ((m_buffer[5] << 8 ) | m_buffer[4]);
175
176 return mraa::SUCCESS;
177 }
178