Erik - / MMA7660

Library for the MMA7660 triple axis accelerometer

Dependents:   Websocket_Ethernet_acc app-board-Sprint-WS-Acc app-board-Ethernet-Websocket app-board-Wifly-Websocket ... more

MMA7660.cpp@4:36a163511e34, 2014-05-13 (annotated)

Committer:
Sissors
Date:
Tue May 13 18:14:34 2014 +0000
Revision:
4:36a163511e34
Parent:
3:89cb08cc663b 
Debug code removed...

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:7bc29a9ea016 1 #include "MMA7660.h"
Sissors 0:7bc29a9ea016 2
Sissors 2:a8e20db7901e 3 MMA7660::MMA7660(PinName sda, PinName scl, bool active) : _i2c(sda, scl)
Sissors 0:7bc29a9ea016 4 {
Sissors 2:a8e20db7901e 5 setActive(active);
Sissors 1:8997a1b348dd 6 samplerate = 64;
Sissors 0:7bc29a9ea016 7 }
Sissors 0:7bc29a9ea016 8
Sissors 0:7bc29a9ea016 9 //Since the MMA lacks a WHO_AM_I register, we can only check if there is a device that answers to the I2C address
Sissors 0:7bc29a9ea016 10 bool MMA7660::testConnection( void )
Sissors 0:7bc29a9ea016 11 {
Sissors 0:7bc29a9ea016 12 if (_i2c.write(MMA7660_ADDRESS, NULL, 0) == 0 )
Sissors 0:7bc29a9ea016 13 return true;
Sissors 0:7bc29a9ea016 14 else
Sissors 0:7bc29a9ea016 15 return false;
Sissors 0:7bc29a9ea016 16 }
Sissors 0:7bc29a9ea016 17
Sissors 0:7bc29a9ea016 18 void MMA7660::setActive(bool state)
Sissors 0:7bc29a9ea016 19 {
Sissors 3:89cb08cc663b 20 active = state;
Sissors 0:7bc29a9ea016 21 char modereg = read(MMA7660_MODE_R);
Sissors 0:7bc29a9ea016 22 modereg &= ~(1<<0);
Sissors 0:7bc29a9ea016 23
Sissors 0:7bc29a9ea016 24 //If it somehow was in testmode, disable that
Sissors 0:7bc29a9ea016 25 if (modereg && (1<<2)) {
Sissors 0:7bc29a9ea016 26 modereg &= ~(1<<2);
Sissors 0:7bc29a9ea016 27 write(MMA7660_MODE_R, modereg);
Sissors 0:7bc29a9ea016 28 }
Sissors 0:7bc29a9ea016 29
Sissors 0:7bc29a9ea016 30 modereg += state;
Sissors 0:7bc29a9ea016 31 write(MMA7660_MODE_R, modereg);
Sissors 0:7bc29a9ea016 32 }
Sissors 0:7bc29a9ea016 33
Sissors 0:7bc29a9ea016 34 void MMA7660::readData(int *data)
Sissors 0:7bc29a9ea016 35 {
Sissors 3:89cb08cc663b 36 bool active_old = active;
Sissors 0:7bc29a9ea016 37 if (!active) {
Sissors 0:7bc29a9ea016 38 setActive(true);
Sissors 1:8997a1b348dd 39 wait(0.012 + 1/samplerate); //Wait until new sample is ready, my experience is that 1/samplerate isnt needed, but datasheet says so
Sissors 0:7bc29a9ea016 40 }
Sissors 0:7bc29a9ea016 41
Sissors 0:7bc29a9ea016 42 char temp[3];
Sissors 0:7bc29a9ea016 43 bool alert;
Sissors 0:7bc29a9ea016 44
Sissors 0:7bc29a9ea016 45 do {
Sissors 0:7bc29a9ea016 46 alert = false;
Sissors 0:7bc29a9ea016 47 read(MMA7660_XOUT_R, temp, 3);
Sissors 0:7bc29a9ea016 48 for (int i = 0; i<3; i++) {
Sissors 0:7bc29a9ea016 49 if (temp[i] > 63)
Sissors 0:7bc29a9ea016 50 alert = true;
Sissors 0:7bc29a9ea016 51 if (temp[i] > 31)
Sissors 0:7bc29a9ea016 52 temp[i] += 128+64;
Sissors 0:7bc29a9ea016 53 data[i] = (signed char)temp[i];
Sissors 0:7bc29a9ea016 54 }
Sissors 0:7bc29a9ea016 55 } while (alert);
Sissors 2:a8e20db7901e 56
Sissors 3:89cb08cc663b 57 if (!active_old)
Sissors 2:a8e20db7901e 58 setActive(false);
Sissors 0:7bc29a9ea016 59 }
Sissors 0:7bc29a9ea016 60
Sissors 1:8997a1b348dd 61
Sissors 0:7bc29a9ea016 62 void MMA7660::readData(float *data)
Sissors 0:7bc29a9ea016 63 {
Sissors 0:7bc29a9ea016 64 int intdata[3];
Sissors 0:7bc29a9ea016 65 readData(intdata);
Sissors 0:7bc29a9ea016 66 for (int i = 0; i<3; i++)
Sissors 0:7bc29a9ea016 67 data[i] = intdata[i]/MMA7660_SENSITIVITY;
Sissors 0:7bc29a9ea016 68 }
Sissors 0:7bc29a9ea016 69
Sissors 2:a8e20db7901e 70 float MMA7660::x( void )
Sissors 1:8997a1b348dd 71 {
Sissors 0:7bc29a9ea016 72 return getSingle(0);
Sissors 1:8997a1b348dd 73 }
Sissors 1:8997a1b348dd 74
Sissors 2:a8e20db7901e 75 float MMA7660::y( void )
Sissors 1:8997a1b348dd 76 {
Sissors 1:8997a1b348dd 77 return getSingle(1);
Sissors 1:8997a1b348dd 78 }
Sissors 1:8997a1b348dd 79
Sissors 2:a8e20db7901e 80 float MMA7660::z( void )
Sissors 1:8997a1b348dd 81 {
Sissors 1:8997a1b348dd 82 return getSingle(2);
Sissors 1:8997a1b348dd 83 }
Sissors 1:8997a1b348dd 84
Sissors 1:8997a1b348dd 85
Sissors 1:8997a1b348dd 86 void MMA7660::setSampleRate(int samplerate)
Sissors 1:8997a1b348dd 87 {
Sissors 3:89cb08cc663b 88 bool active_old = active;
Sissors 1:8997a1b348dd 89 setActive(false); //Not allowed to be active to change anything
Sissors 1:8997a1b348dd 90 int rates[] = {120, 64, 32, 16, 8, 4, 2, 1}; //Alowed samplerates (and their number in array is also number required for MMA)
Sissors 1:8997a1b348dd 91 int sampleLoc = 0, sampleError = 10000, temp;
Sissors 1:8997a1b348dd 92 for (int i = 0; i<8; i++) {
Sissors 1:8997a1b348dd 93 temp = abs( rates[i] - samplerate );
Sissors 1:8997a1b348dd 94 if (temp<sampleError) {
Sissors 1:8997a1b348dd 95 sampleLoc = i;
Sissors 1:8997a1b348dd 96 sampleError=temp;
Sissors 1:8997a1b348dd 97 }
Sissors 0:7bc29a9ea016 98 }
Sissors 0:7bc29a9ea016 99
Sissors 1:8997a1b348dd 100 //Update the samplerate reg
Sissors 1:8997a1b348dd 101 temp = read(MMA7660_SR_R);
Sissors 2:a8e20db7901e 102 temp &= ~0x07; //Awake sample rate are lowest 3 bit
Sissors 1:8997a1b348dd 103 temp |= sampleLoc;
Sissors 1:8997a1b348dd 104 write(MMA7660_SR_R, temp);
Sissors 1:8997a1b348dd 105 this->samplerate = rates[sampleLoc];
Sissors 3:89cb08cc663b 106 setActive(active_old); //Restore previous active state
Sissors 1:8997a1b348dd 107 }
Sissors 1:8997a1b348dd 108
Sissors 1:8997a1b348dd 109
Sissors 1:8997a1b348dd 110 MMA7660::Orientation MMA7660::getSide( void )
Sissors 1:8997a1b348dd 111 {
Sissors 1:8997a1b348dd 112 char tiltreg = read(MMA7660_TILT_R);
Sissors 1:8997a1b348dd 113 //We care about 2 LSBs
Sissors 1:8997a1b348dd 114 tiltreg &= 0x03;
Sissors 1:8997a1b348dd 115 if (tiltreg == 0x01)
Sissors 1:8997a1b348dd 116 return MMA7660::Front;
Sissors 1:8997a1b348dd 117 if (tiltreg == 0x02)
Sissors 1:8997a1b348dd 118 return MMA7660::Back;
Sissors 1:8997a1b348dd 119 return MMA7660::Unknown;
Sissors 1:8997a1b348dd 120 }
Sissors 1:8997a1b348dd 121
Sissors 1:8997a1b348dd 122 MMA7660::Orientation MMA7660::getOrientation( void )
Sissors 1:8997a1b348dd 123 {
Sissors 1:8997a1b348dd 124 char tiltreg = read(MMA7660_TILT_R);
Sissors 1:8997a1b348dd 125
Sissors 1:8997a1b348dd 126 //We care about bit 2, 3 and 4 (counting from zero)
Sissors 1:8997a1b348dd 127 tiltreg &= 0x07<<2;
Sissors 1:8997a1b348dd 128 tiltreg >>= 2;
Sissors 1:8997a1b348dd 129 if (tiltreg == 0x01)
Sissors 1:8997a1b348dd 130 return MMA7660::Left;
Sissors 1:8997a1b348dd 131 if (tiltreg == 0x02)
Sissors 1:8997a1b348dd 132 return MMA7660::Right;
Sissors 1:8997a1b348dd 133 if (tiltreg == 0x05)
Sissors 1:8997a1b348dd 134 return MMA7660::Down;
Sissors 1:8997a1b348dd 135 if (tiltreg == 0x06)
Sissors 1:8997a1b348dd 136 return MMA7660::Up;
Sissors 1:8997a1b348dd 137 return MMA7660::Unknown;
Sissors 1:8997a1b348dd 138 }
Sissors 1:8997a1b348dd 139
Sissors 2:a8e20db7901e 140
Sissors 1:8997a1b348dd 141
Sissors 1:8997a1b348dd 142 //////////////////////////////////////////////
Sissors 1:8997a1b348dd 143 ///////////////PRIVATE////////////////////////
Sissors 1:8997a1b348dd 144 //////////////////////////////////////////////
Sissors 1:8997a1b348dd 145
Sissors 0:7bc29a9ea016 146
Sissors 0:7bc29a9ea016 147 void MMA7660::write(char address, char data)
Sissors 0:7bc29a9ea016 148 {
Sissors 0:7bc29a9ea016 149 char temp[2];
Sissors 0:7bc29a9ea016 150 temp[0]=address;
Sissors 0:7bc29a9ea016 151 temp[1]=data;
Sissors 0:7bc29a9ea016 152
Sissors 0:7bc29a9ea016 153 _i2c.write(MMA7660_ADDRESS, temp, 2);
Sissors 0:7bc29a9ea016 154 }
Sissors 0:7bc29a9ea016 155
Sissors 0:7bc29a9ea016 156 char MMA7660::read(char address)
Sissors 0:7bc29a9ea016 157 {
Sissors 0:7bc29a9ea016 158 char retval;
Sissors 0:7bc29a9ea016 159 _i2c.write(MMA7660_ADDRESS, &address, 1, true);
Sissors 0:7bc29a9ea016 160 _i2c.read(MMA7660_ADDRESS, &retval, 1);
Sissors 0:7bc29a9ea016 161 return retval;
Sissors 0:7bc29a9ea016 162 }
Sissors 0:7bc29a9ea016 163
Sissors 0:7bc29a9ea016 164 void MMA7660::read(char address, char *data, int length)
Sissors 0:7bc29a9ea016 165 {
Sissors 0:7bc29a9ea016 166 _i2c.write(MMA7660_ADDRESS, &address, 1, true);
Sissors 0:7bc29a9ea016 167 _i2c.read(MMA7660_ADDRESS, data, length);
Sissors 0:7bc29a9ea016 168 }
Sissors 0:7bc29a9ea016 169
Sissors 0:7bc29a9ea016 170 float MMA7660::getSingle( int number )
Sissors 0:7bc29a9ea016 171 {
Sissors 3:89cb08cc663b 172 bool active_old = active;
Sissors 0:7bc29a9ea016 173 if (!active) {
Sissors 0:7bc29a9ea016 174 setActive(true);
Sissors 1:8997a1b348dd 175 wait(0.012 + 1/samplerate); //Wait until new sample is ready
Sissors 0:7bc29a9ea016 176 }
Sissors 0:7bc29a9ea016 177
Sissors 0:7bc29a9ea016 178 signed char temp;
Sissors 0:7bc29a9ea016 179 bool alert;
Sissors 0:7bc29a9ea016 180
Sissors 0:7bc29a9ea016 181 do {
Sissors 0:7bc29a9ea016 182 alert = false;
Sissors 0:7bc29a9ea016 183 temp = read(MMA7660_XOUT_R + number);
Sissors 0:7bc29a9ea016 184 if (temp > 63)
Sissors 0:7bc29a9ea016 185 alert = true;
Sissors 0:7bc29a9ea016 186 if (temp > 31)
Sissors 0:7bc29a9ea016 187 temp += 128+64;
Sissors 2:a8e20db7901e 188 } while (alert);
Sissors 0:7bc29a9ea016 189
Sissors 3:89cb08cc663b 190 if (!active_old)
Sissors 2:a8e20db7901e 191 setActive(false);
Sissors 0:7bc29a9ea016 192
Sissors 0:7bc29a9ea016 193 return temp / MMA7660_SENSITIVITY;
Sissors 0:7bc29a9ea016 194 }