1 /* 2 * Author: Mihai Tudor Panu <mihai.tudor.panu (at) 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 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* 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* 141 Adxl345::getRawValues() 142 { 143 return &m_rawaccel[0]; 144 } 145 146 uint8_t 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 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
