S5_mbed / MMA8452

library mma8452

Dependents:   APP3_Capteur_V2

Fork of MMA8452 by Ashley Mills

MMA8452.cpp@10:ca9ba7ad4e94, 2014-03-04 (annotated)

Committer:
ashleymills
Date:
Tue Mar 04 11:14:34 2014 +0000
Revision:
10:ca9ba7ad4e94
Parent:
9:dfb0f6a7a455
Child:
11:dfd1e0afcb7b
Some minor changes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nherriot 0:bcf2aa85d7f9 1 // Author: Nicholas Herriot
nherriot 0:bcf2aa85d7f9 2 /* Copyright (c) 2013 Vodafone, MIT License
nherriot 0:bcf2aa85d7f9 3 *
nherriot 0:bcf2aa85d7f9 4 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
nherriot 0:bcf2aa85d7f9 5 * and associated documentation files (the "Software"), to deal in the Software without restriction,
nherriot 0:bcf2aa85d7f9 6 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
nherriot 0:bcf2aa85d7f9 7 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
nherriot 0:bcf2aa85d7f9 8 * furnished to do so, subject to the following conditions:
nherriot 0:bcf2aa85d7f9 9 *
nherriot 0:bcf2aa85d7f9 10 * The above copyright notice and this permission notice shall be included in all copies or
nherriot 0:bcf2aa85d7f9 11 * substantial portions of the Software.
nherriot 0:bcf2aa85d7f9 12 *
nherriot 0:bcf2aa85d7f9 13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
nherriot 0:bcf2aa85d7f9 14 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
nherriot 0:bcf2aa85d7f9 15 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
nherriot 0:bcf2aa85d7f9 16 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
nherriot 0:bcf2aa85d7f9 17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nherriot 0:bcf2aa85d7f9 18 */
nherriot 0:bcf2aa85d7f9 19
nherriot 0:bcf2aa85d7f9 20 # include "MMA8452.h"
nherriot 0:bcf2aa85d7f9 21
nherriot 0:bcf2aa85d7f9 22 // Connect module at I2C address using I2C port pins sda and scl
ashleymills 10:ca9ba7ad4e94 23 MMA8452::MMA8452(PinName sda, PinName scl,int frequency) : m_i2c(sda, scl) , m_frequency(frequency) {
nherriot 0:bcf2aa85d7f9 24 //m_i2c.frequency(m_frequency);
ashleymills 6:f6bde04bf8be 25
ashleymills 6:f6bde04bf8be 26 // setup read and write addresses to avoid duplication
ashleymills 6:f6bde04bf8be 27 _readAddress = (MMA8452_ADDRESS<<1) | 0x01;
ashleymills 6:f6bde04bf8be 28 _writeAddress = (MMA8452_ADDRESS<<1) & 0xFE;
nherriot 0:bcf2aa85d7f9 29 }
nherriot 0:bcf2aa85d7f9 30
nherriot 0:bcf2aa85d7f9 31
nherriot 0:bcf2aa85d7f9 32 // Destroys instance
ashleymills 10:ca9ba7ad4e94 33 MMA8452::~MMA8452() {}
nherriot 0:bcf2aa85d7f9 34
nherriot 0:bcf2aa85d7f9 35 // Setting the control register bit 1 to true to activate the MMA8452
ashleymills 10:ca9ba7ad4e94 36 int MMA8452::activate() {
ashleymills 6:f6bde04bf8be 37 // set control register 1 to active
ashleymills 6:f6bde04bf8be 38 char init[2] = {CTRL_REG_1,ACTIVE};
nherriot 3:ffb0b1650ca2 39
ashleymills 6:f6bde04bf8be 40 // perform write and return error code
ashleymills 6:f6bde04bf8be 41 return m_i2c.write(_writeAddress,init,2);
nherriot 3:ffb0b1650ca2 42 }
nherriot 3:ffb0b1650ca2 43
nherriot 3:ffb0b1650ca2 44
nherriot 5:b3d0abd97e55 45 // Get 'Fast Read Mode' called F_READ. If bit 1 is set '1' then F_READ is active. Fast read will skip LSB when reading xyz
nherriot 5:b3d0abd97e55 46 // resisters from 0x01 to 0x06. When F_READ is '0' then all 6 registers will be read.
nherriot 5:b3d0abd97e55 47
ashleymills 10:ca9ba7ad4e94 48 int MMA8452::get_CTRL_Reg1(int* dst)
ashleymills 9:dfb0f6a7a455 49 {
ashleymills 10:ca9ba7ad4e94 50 return readRegister(CTRL_REG_1,dst);
nherriot 5:b3d0abd97e55 51 }
nherriot 5:b3d0abd97e55 52
nherriot 3:ffb0b1650ca2 53 // Setting the control register bit 1 to true to activate the MMA8452
ashleymills 10:ca9ba7ad4e94 54 int MMA8452::standby()
nherriot 3:ffb0b1650ca2 55 {
ashleymills 8:89272163f395 56 // set control register 1 to standby
ashleymills 8:89272163f395 57 char init[2] = {CTRL_REG_1,STANDBY};
nherriot 1:ef026bf28798 58
ashleymills 8:89272163f395 59 // write to the register and return the error code
ashleymills 8:89272163f395 60 return m_i2c.write(_writeAddress,init,2);
nherriot 0:bcf2aa85d7f9 61 }
nherriot 0:bcf2aa85d7f9 62
nherriot 0:bcf2aa85d7f9 63
nherriot 3:ffb0b1650ca2 64
nherriot 0:bcf2aa85d7f9 65 // Device initialization
ashleymills 10:ca9ba7ad4e94 66 void MMA8452::init()
nherriot 0:bcf2aa85d7f9 67 {
nherriot 0:bcf2aa85d7f9 68
ashleymills 10:ca9ba7ad4e94 69 writeRegister(INTSU_STATUS, 0x10); // automatic interrupt after every measurement
ashleymills 10:ca9ba7ad4e94 70 writeRegister(SR_STATUS, 0x00); // 120 Samples/Second
ashleymills 10:ca9ba7ad4e94 71 writeRegister(MODE_STATUS, 0x01); // Active Mode
nherriot 0:bcf2aa85d7f9 72
nherriot 0:bcf2aa85d7f9 73 }
nherriot 0:bcf2aa85d7f9 74
nherriot 3:ffb0b1650ca2 75 // Get real time status of device - it can be STANDBY, WAKE or SLEEP
ashleymills 10:ca9ba7ad4e94 76 int MMA8452::getSystemMode(int *dst)
nherriot 3:ffb0b1650ca2 77 {
ashleymills 10:ca9ba7ad4e94 78 return readRegister(SYSMOD,dst);
nherriot 3:ffb0b1650ca2 79 }
nherriot 3:ffb0b1650ca2 80
nherriot 3:ffb0b1650ca2 81
nherriot 3:ffb0b1650ca2 82
nherriot 3:ffb0b1650ca2 83 // Get real time status of device - it can be STANDBY, WAKE or SLEEP
ashleymills 10:ca9ba7ad4e94 84 int MMA8452::getStatus(int* dst)
nherriot 3:ffb0b1650ca2 85 {
ashleymills 10:ca9ba7ad4e94 86 return readRegister(STATUS,dst);
nherriot 3:ffb0b1650ca2 87 }
nherriot 3:ffb0b1650ca2 88
nherriot 0:bcf2aa85d7f9 89
nherriot 1:ef026bf28798 90 // Get device ID
ashleymills 10:ca9ba7ad4e94 91 int MMA8452::getDeviceID(int *dst)
nherriot 1:ef026bf28798 92 {
ashleymills 10:ca9ba7ad4e94 93 return readRegister(WHO_AM_I,dst);
nherriot 1:ef026bf28798 94 }
nherriot 1:ef026bf28798 95
nherriot 1:ef026bf28798 96
nherriot 3:ffb0b1650ca2 97 /*
nherriot 3:ffb0b1650ca2 98 // Reads x data
ashleymills 10:ca9ba7ad4e94 99 int MMA8452::read_x(int& xaxisLSB)
nherriot 0:bcf2aa85d7f9 100 {
nherriot 3:ffb0b1650ca2 101 char mcu_address = (MMA8452_ADDRESS<<1);
nherriot 3:ffb0b1650ca2 102 m_i2c.start();
nherriot 3:ffb0b1650ca2 103 if( m_i2c.write( mcu_address & 0xFE) == 0) // just good practice to force bit 1 to a '0' by ANDing with 0xFE
nherriot 3:ffb0b1650ca2 104 {
nherriot 3:ffb0b1650ca2 105 return 1; // we failed to write the mcu address on the bus to initiate dialogue
nherriot 3:ffb0b1650ca2 106 }
nherriot 3:ffb0b1650ca2 107 if( m_i2c.write( OUT_X_MSB) == 0)
nherriot 3:ffb0b1650ca2 108 {
nherriot 3:ffb0b1650ca2 109 return 1; // we failed to write 'X axis LSB' to the chip
nherriot 3:ffb0b1650ca2 110 }
nherriot 3:ffb0b1650ca2 111 m_i2c.start();
nherriot 3:ffb0b1650ca2 112 if( m_i2c.write( mcu_address | 0x01) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API...
nherriot 3:ffb0b1650ca2 113 {
nherriot 3:ffb0b1650ca2 114 return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus
nherriot 3:ffb0b1650ca2 115 }
nherriot 3:ffb0b1650ca2 116 xaxisLSB = m_i2c.read(0);
nherriot 3:ffb0b1650ca2 117 m_i2c.stop();
nherriot 3:ffb0b1650ca2 118 return 0;
nherriot 3:ffb0b1650ca2 119 }
nherriot 3:ffb0b1650ca2 120 */
nherriot 0:bcf2aa85d7f9 121
ashleymills 10:ca9ba7ad4e94 122 int MMA8452::readRaw(char src, char *dst, int len) {
ashleymills 8:89272163f395 123 // this is the register we want to get data from
ashleymills 8:89272163f395 124 char register_address[1];
ashleymills 8:89272163f395 125 register_address[0] = src;
ashleymills 8:89272163f395 126
ashleymills 8:89272163f395 127 if(m_i2c.write(_writeAddress,register_address,1,true) == 0)
ashleymills 8:89272163f395 128 {
ashleymills 8:89272163f395 129 if(m_i2c.read(_readAddress,dst,len)==0)
ashleymills 8:89272163f395 130 {
ashleymills 8:89272163f395 131 return 0;
ashleymills 8:89272163f395 132 }
ashleymills 8:89272163f395 133 }
ashleymills 8:89272163f395 134
ashleymills 8:89272163f395 135 // failure case, zero array and return error
ashleymills 8:89272163f395 136 for(int i=0; i<len; i++) {
ashleymills 8:89272163f395 137 dst[i] = 0x00;
ashleymills 8:89272163f395 138 }
ashleymills 8:89272163f395 139 return 1;
ashleymills 8:89272163f395 140 }
nherriot 3:ffb0b1650ca2 141
nherriot 3:ffb0b1650ca2 142 // Reads x data. This method reads two registers containing the x-axis values from the accelerometer.
nherriot 3:ffb0b1650ca2 143 // It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array
nherriot 3:ffb0b1650ca2 144 // is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns
nherriot 3:ffb0b1650ca2 145 // the raw data.
ashleymills 10:ca9ba7ad4e94 146 //int MMA8452::read_x(int& xaxisLSB)
ashleymills 10:ca9ba7ad4e94 147 int MMA8452::readRawX(char *xaxis)
ashleymills 8:89272163f395 148 {
ashleymills 10:ca9ba7ad4e94 149 return readRaw(OUT_X_MSB,xaxis,2);
nherriot 0:bcf2aa85d7f9 150 }
nherriot 0:bcf2aa85d7f9 151
nherriot 0:bcf2aa85d7f9 152
nherriot 3:ffb0b1650ca2 153 // Reads y data. This method reads two registers containing the x-axis values from the accelerometer.
nherriot 3:ffb0b1650ca2 154 // It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array
nherriot 3:ffb0b1650ca2 155 // is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns
nherriot 3:ffb0b1650ca2 156 // the raw data.
nherriot 3:ffb0b1650ca2 157
ashleymills 10:ca9ba7ad4e94 158 int MMA8452::readRawY(char *yaxis) {
ashleymills 10:ca9ba7ad4e94 159 return readRaw(OUT_Y_MSB,yaxis,2);
nherriot 3:ffb0b1650ca2 160 }
nherriot 3:ffb0b1650ca2 161
nherriot 0:bcf2aa85d7f9 162
nherriot 3:ffb0b1650ca2 163
nherriot 3:ffb0b1650ca2 164 // Reads z data. This method reads two registers containing the x-axis values from the accelerometer.
nherriot 3:ffb0b1650ca2 165 // It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array
nherriot 3:ffb0b1650ca2 166 // is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns
nherriot 3:ffb0b1650ca2 167 // the raw data.
nherriot 3:ffb0b1650ca2 168
ashleymills 10:ca9ba7ad4e94 169 int MMA8452::readRawZ(char *zaxis)
nherriot 3:ffb0b1650ca2 170 {
ashleymills 10:ca9ba7ad4e94 171 return readRaw(OUT_Z_MSB,zaxis,2);
nherriot 3:ffb0b1650ca2 172 }
nherriot 0:bcf2aa85d7f9 173
nherriot 0:bcf2aa85d7f9 174
nherriot 0:bcf2aa85d7f9 175
nherriot 0:bcf2aa85d7f9 176 // Reads y data
ashleymills 10:ca9ba7ad4e94 177 int MMA8452::read_y()
nherriot 0:bcf2aa85d7f9 178 {
nherriot 1:ef026bf28798 179 char mcu_address = (MMA8452_ADDRESS <<1);
nherriot 0:bcf2aa85d7f9 180
nherriot 0:bcf2aa85d7f9 181 m_i2c.start(); // Start
nherriot 0:bcf2aa85d7f9 182 m_i2c.write(mcu_address); // A write to device 0x98
nherriot 0:bcf2aa85d7f9 183 m_i2c.write(OUT_Y_MSB); // Register to read
nherriot 0:bcf2aa85d7f9 184 m_i2c.start();
nherriot 0:bcf2aa85d7f9 185 m_i2c.write(mcu_address); // Read from device 0x99
nherriot 1:ef026bf28798 186 int y = m_i2c.read(0); // Read the data
nherriot 0:bcf2aa85d7f9 187 m_i2c.stop();
nherriot 0:bcf2aa85d7f9 188
nherriot 1:ef026bf28798 189 return y;
nherriot 0:bcf2aa85d7f9 190
nherriot 0:bcf2aa85d7f9 191 }
nherriot 0:bcf2aa85d7f9 192
nherriot 0:bcf2aa85d7f9 193
nherriot 0:bcf2aa85d7f9 194 // Reads z data
ashleymills 10:ca9ba7ad4e94 195 int MMA8452::read_z()
nherriot 0:bcf2aa85d7f9 196 {
nherriot 1:ef026bf28798 197 char mcu_address = (MMA8452_ADDRESS <<1);
nherriot 0:bcf2aa85d7f9 198
nherriot 0:bcf2aa85d7f9 199 m_i2c.start(); // Start
nherriot 0:bcf2aa85d7f9 200 m_i2c.write(mcu_address); // A write to device 0x98
nherriot 0:bcf2aa85d7f9 201 m_i2c.write(OUT_Z_MSB); // Register to read
nherriot 0:bcf2aa85d7f9 202 m_i2c.start();
nherriot 0:bcf2aa85d7f9 203 m_i2c.write(mcu_address); // Read from device 0x99
nherriot 1:ef026bf28798 204 int z = m_i2c.read(0); // Read the data
nherriot 0:bcf2aa85d7f9 205 m_i2c.stop();
nherriot 0:bcf2aa85d7f9 206
nherriot 1:ef026bf28798 207 return z;
nherriot 0:bcf2aa85d7f9 208
nherriot 0:bcf2aa85d7f9 209 }
nherriot 0:bcf2aa85d7f9 210
nherriot 0:bcf2aa85d7f9 211
nherriot 0:bcf2aa85d7f9 212 // Reads xyz
ashleymills 10:ca9ba7ad4e94 213 int MMA8452::readRawXYZ(char *x, char *y, char *z)
nherriot 1:ef026bf28798 214 {
nherriot 1:ef026bf28798 215
nherriot 1:ef026bf28798 216
nherriot 1:ef026bf28798 217 char mcu_address = (MMA8452_ADDRESS <<1);
nherriot 1:ef026bf28798 218 char register_buffer[6] ={0,0,0,0,0,0};
nherriot 1:ef026bf28798 219 const char Addr_X = OUT_X_MSB;
nherriot 1:ef026bf28798 220 m_i2c.write(mcu_address); // A write to device 0x98
nherriot 1:ef026bf28798 221 m_i2c.write(MMA8452_ADDRESS, &Addr_X, 1); // Pointer to the OUT_X_MSB register
nherriot 1:ef026bf28798 222
nherriot 1:ef026bf28798 223 if(m_i2c.write(mcu_address,&Addr_X,1) == 0)
nherriot 1:ef026bf28798 224 {
nherriot 1:ef026bf28798 225 if(m_i2c.read(mcu_address,register_buffer,6) == 0)
nherriot 1:ef026bf28798 226 {
nherriot 1:ef026bf28798 227 *x = register_buffer[1];
nherriot 1:ef026bf28798 228 *y = register_buffer[3];
nherriot 1:ef026bf28798 229 *z = register_buffer[5];
nherriot 1:ef026bf28798 230 return 0; // yahoooooo
nherriot 1:ef026bf28798 231 }
nherriot 1:ef026bf28798 232 else
nherriot 1:ef026bf28798 233 {
nherriot 1:ef026bf28798 234 return 1; // failed oh nooo!
nherriot 1:ef026bf28798 235 }
nherriot 1:ef026bf28798 236 }
nherriot 1:ef026bf28798 237 else
nherriot 1:ef026bf28798 238 {
nherriot 1:ef026bf28798 239 return 1; // failed oh nooo!
nherriot 1:ef026bf28798 240 }
nherriot 0:bcf2aa85d7f9 241
nherriot 1:ef026bf28798 242 }
nherriot 0:bcf2aa85d7f9 243
nherriot 0:bcf2aa85d7f9 244 // Write register (The device must be placed in Standby Mode to change the value of the registers)
ashleymills 10:ca9ba7ad4e94 245 void MMA8452::writeRegister(char addr, char data)
nherriot 0:bcf2aa85d7f9 246 {
nherriot 0:bcf2aa85d7f9 247
nherriot 0:bcf2aa85d7f9 248 char cmd[2] = {0, 0};
nherriot 0:bcf2aa85d7f9 249
nherriot 0:bcf2aa85d7f9 250 cmd[0] = MODE_STATUS;
nherriot 0:bcf2aa85d7f9 251 cmd[1] = 0x00; // Standby Mode on
nherriot 0:bcf2aa85d7f9 252 m_i2c.write(MMA8452_ADDRESS, cmd, 2);
nherriot 0:bcf2aa85d7f9 253
nherriot 0:bcf2aa85d7f9 254 cmd[0] = addr;
nherriot 0:bcf2aa85d7f9 255 cmd[1] = data; // New value of the register
nherriot 0:bcf2aa85d7f9 256 m_i2c.write(MMA8452_ADDRESS, cmd, 2);
nherriot 0:bcf2aa85d7f9 257
nherriot 0:bcf2aa85d7f9 258 cmd[0] = MODE_STATUS;
nherriot 0:bcf2aa85d7f9 259 cmd[1] = 0x01; // Active Mode on
nherriot 0:bcf2aa85d7f9 260 m_i2c.write(MMA8452_ADDRESS, cmd, 2);
nherriot 0:bcf2aa85d7f9 261
nherriot 0:bcf2aa85d7f9 262 }
nherriot 0:bcf2aa85d7f9 263
nherriot 0:bcf2aa85d7f9 264 // Read from specified MMA7660FC register
ashleymills 10:ca9ba7ad4e94 265 int MMA8452::readRegister(char addr, int *dst)
nherriot 0:bcf2aa85d7f9 266 {
nherriot 0:bcf2aa85d7f9 267
ashleymills 8:89272163f395 268 m_i2c.start();
ashleymills 8:89272163f395 269 if( m_i2c.write(_writeAddress) == 0)
ashleymills 8:89272163f395 270 {
ashleymills 8:89272163f395 271 return 1; // we failed to write the mcu address on the bus to initiate dialogue
ashleymills 8:89272163f395 272 }
ashleymills 9:dfb0f6a7a455 273 if( m_i2c.write(addr) == 0)
ashleymills 8:89272163f395 274 {
ashleymills 8:89272163f395 275 return 1; // we failed to write 'status' to the chip
ashleymills 8:89272163f395 276 }
ashleymills 8:89272163f395 277 m_i2c.start();
ashleymills 8:89272163f395 278 if( m_i2c.write(_readAddress) == 0) // this is asking to read the slave mcu address - even though it's a 'write' method!!! Crap API...
ashleymills 8:89272163f395 279 {
ashleymills 8:89272163f395 280 return 1; // we failed to request a read from that mcu - this really is just writing the mcu vaule on the bus
ashleymills 8:89272163f395 281 }
ashleymills 9:dfb0f6a7a455 282 *dst = m_i2c.read(0);
ashleymills 8:89272163f395 283 m_i2c.stop();
nherriot 0:bcf2aa85d7f9 284
ashleymills 9:dfb0f6a7a455 285 return 0;
nherriot 0:bcf2aa85d7f9 286
nherriot 0:bcf2aa85d7f9 287 }