Library for the MMA7660 triple axis accelerometer
Fork of MMA7660 by
MMA7660.cpp@1:8997a1b348dd, 2012-10-16 (annotated)
- Committer:
- Sissors
- Date:
- Tue Oct 16 19:42:19 2012 +0000
- Revision:
- 1:8997a1b348dd
- Parent:
- 0:7bc29a9ea016
- Child:
- 2:a8e20db7901e
Tapping doesnt work yet
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
Sissors | 0:7bc29a9ea016 | 1 | #include "MMA7660.h" |
Sissors | 0:7bc29a9ea016 | 2 | |
Sissors | 0:7bc29a9ea016 | 3 | MMA7660::MMA7660(PinName sda, PinName scl, PinName interrupt) : _i2c(sda, scl) |
Sissors | 0:7bc29a9ea016 | 4 | { |
Sissors | 0:7bc29a9ea016 | 5 | _interrupt = interrupt; |
Sissors | 0:7bc29a9ea016 | 6 | active = false; |
Sissors | 1:8997a1b348dd | 7 | samplerate = 64; |
Sissors | 1:8997a1b348dd | 8 | |
Sissors | 0:7bc29a9ea016 | 9 | } |
Sissors | 0:7bc29a9ea016 | 10 | |
Sissors | 0:7bc29a9ea016 | 11 | //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 | 12 | bool MMA7660::testConnection( void ) |
Sissors | 0:7bc29a9ea016 | 13 | { |
Sissors | 0:7bc29a9ea016 | 14 | if (_i2c.write(MMA7660_ADDRESS, NULL, 0) == 0 ) |
Sissors | 0:7bc29a9ea016 | 15 | return true; |
Sissors | 0:7bc29a9ea016 | 16 | else |
Sissors | 0:7bc29a9ea016 | 17 | return false; |
Sissors | 0:7bc29a9ea016 | 18 | } |
Sissors | 0:7bc29a9ea016 | 19 | |
Sissors | 0:7bc29a9ea016 | 20 | void MMA7660::setActive(bool state) |
Sissors | 0:7bc29a9ea016 | 21 | { |
Sissors | 0:7bc29a9ea016 | 22 | char modereg = read(MMA7660_MODE_R); |
Sissors | 0:7bc29a9ea016 | 23 | modereg &= ~(1<<0); |
Sissors | 0:7bc29a9ea016 | 24 | |
Sissors | 0:7bc29a9ea016 | 25 | //If it somehow was in testmode, disable that |
Sissors | 0:7bc29a9ea016 | 26 | if (modereg && (1<<2)) { |
Sissors | 0:7bc29a9ea016 | 27 | modereg &= ~(1<<2); |
Sissors | 0:7bc29a9ea016 | 28 | write(MMA7660_MODE_R, modereg); |
Sissors | 0:7bc29a9ea016 | 29 | } |
Sissors | 0:7bc29a9ea016 | 30 | |
Sissors | 0:7bc29a9ea016 | 31 | modereg += state; |
Sissors | 0:7bc29a9ea016 | 32 | write(MMA7660_MODE_R, modereg); |
Sissors | 0:7bc29a9ea016 | 33 | } |
Sissors | 0:7bc29a9ea016 | 34 | |
Sissors | 0:7bc29a9ea016 | 35 | //Add timeout! |
Sissors | 0:7bc29a9ea016 | 36 | void MMA7660::readData(int *data) |
Sissors | 0:7bc29a9ea016 | 37 | { |
Sissors | 0:7bc29a9ea016 | 38 | if (!active) { |
Sissors | 0:7bc29a9ea016 | 39 | setActive(true); |
Sissors | 0:7bc29a9ea016 | 40 | active = true; |
Sissors | 1:8997a1b348dd | 41 | 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 | 42 | } |
Sissors | 0:7bc29a9ea016 | 43 | |
Sissors | 0:7bc29a9ea016 | 44 | char temp[3]; |
Sissors | 0:7bc29a9ea016 | 45 | bool alert; |
Sissors | 0:7bc29a9ea016 | 46 | |
Sissors | 0:7bc29a9ea016 | 47 | do { |
Sissors | 0:7bc29a9ea016 | 48 | alert = false; |
Sissors | 0:7bc29a9ea016 | 49 | read(MMA7660_XOUT_R, temp, 3); |
Sissors | 0:7bc29a9ea016 | 50 | for (int i = 0; i<3; i++) { |
Sissors | 0:7bc29a9ea016 | 51 | if (temp[i] > 63) |
Sissors | 0:7bc29a9ea016 | 52 | alert = true; |
Sissors | 0:7bc29a9ea016 | 53 | if (temp[i] > 31) |
Sissors | 0:7bc29a9ea016 | 54 | temp[i] += 128+64; |
Sissors | 0:7bc29a9ea016 | 55 | data[i] = (signed char)temp[i]; |
Sissors | 0:7bc29a9ea016 | 56 | } |
Sissors | 0:7bc29a9ea016 | 57 | } while (alert); |
Sissors | 0:7bc29a9ea016 | 58 | } |
Sissors | 0:7bc29a9ea016 | 59 | |
Sissors | 1:8997a1b348dd | 60 | |
Sissors | 0:7bc29a9ea016 | 61 | void MMA7660::readData(float *data) |
Sissors | 0:7bc29a9ea016 | 62 | { |
Sissors | 0:7bc29a9ea016 | 63 | int intdata[3]; |
Sissors | 0:7bc29a9ea016 | 64 | readData(intdata); |
Sissors | 0:7bc29a9ea016 | 65 | for (int i = 0; i<3; i++) |
Sissors | 0:7bc29a9ea016 | 66 | data[i] = intdata[i]/MMA7660_SENSITIVITY; |
Sissors | 0:7bc29a9ea016 | 67 | } |
Sissors | 0:7bc29a9ea016 | 68 | |
Sissors | 1:8997a1b348dd | 69 | float MMA7660::getX( void ) |
Sissors | 1:8997a1b348dd | 70 | { |
Sissors | 0:7bc29a9ea016 | 71 | return getSingle(0); |
Sissors | 1:8997a1b348dd | 72 | } |
Sissors | 1:8997a1b348dd | 73 | |
Sissors | 1:8997a1b348dd | 74 | float MMA7660::getY( void ) |
Sissors | 1:8997a1b348dd | 75 | { |
Sissors | 1:8997a1b348dd | 76 | return getSingle(1); |
Sissors | 1:8997a1b348dd | 77 | } |
Sissors | 1:8997a1b348dd | 78 | |
Sissors | 1:8997a1b348dd | 79 | float MMA7660::getZ( void ) |
Sissors | 1:8997a1b348dd | 80 | { |
Sissors | 1:8997a1b348dd | 81 | return getSingle(2); |
Sissors | 1:8997a1b348dd | 82 | } |
Sissors | 1:8997a1b348dd | 83 | |
Sissors | 1:8997a1b348dd | 84 | |
Sissors | 1:8997a1b348dd | 85 | void MMA7660::setSampleRate(int samplerate) |
Sissors | 1:8997a1b348dd | 86 | { |
Sissors | 1:8997a1b348dd | 87 | setActive(false); //Not allowed to be active to change anything |
Sissors | 1:8997a1b348dd | 88 | 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 | 89 | int sampleLoc = 0, sampleError = 10000, temp; |
Sissors | 1:8997a1b348dd | 90 | for (int i = 0; i<8; i++) { |
Sissors | 1:8997a1b348dd | 91 | temp = abs( rates[i] - samplerate ); |
Sissors | 1:8997a1b348dd | 92 | if (temp<sampleError) { |
Sissors | 1:8997a1b348dd | 93 | sampleLoc = i; |
Sissors | 1:8997a1b348dd | 94 | sampleError=temp; |
Sissors | 1:8997a1b348dd | 95 | } |
Sissors | 0:7bc29a9ea016 | 96 | } |
Sissors | 0:7bc29a9ea016 | 97 | |
Sissors | 1:8997a1b348dd | 98 | //Update the samplerate reg |
Sissors | 1:8997a1b348dd | 99 | temp = read(MMA7660_SR_R); |
Sissors | 1:8997a1b348dd | 100 | temp &= ~0x07; //Awake sample rate are lowest 3 bit |
Sissors | 1:8997a1b348dd | 101 | temp |= sampleLoc; |
Sissors | 1:8997a1b348dd | 102 | write(MMA7660_SR_R, temp); |
Sissors | 1:8997a1b348dd | 103 | this->samplerate = rates[sampleLoc]; |
Sissors | 1:8997a1b348dd | 104 | setActive(active); //Restore previous active state |
Sissors | 1:8997a1b348dd | 105 | } |
Sissors | 1:8997a1b348dd | 106 | |
Sissors | 1:8997a1b348dd | 107 | MMA7660::Orientation MMA7660::getGlobalOrientation( void ) |
Sissors | 1:8997a1b348dd | 108 | { |
Sissors | 1:8997a1b348dd | 109 | int retval = MMA7660::Unknown; |
Sissors | 1:8997a1b348dd | 110 | |
Sissors | 1:8997a1b348dd | 111 | int accelerations[3]; |
Sissors | 1:8997a1b348dd | 112 | readData(accelerations); |
Sissors | 1:8997a1b348dd | 113 | |
Sissors | 1:8997a1b348dd | 114 | //Check which side is up |
Sissors | 1:8997a1b348dd | 115 | int max = 0; |
Sissors | 1:8997a1b348dd | 116 | for (int i = 0; i<3; i++) { |
Sissors | 1:8997a1b348dd | 117 | if (-accelerations[i] > max) { |
Sissors | 1:8997a1b348dd | 118 | max = -accelerations[i]; |
Sissors | 1:8997a1b348dd | 119 | retval = 2 * i; |
Sissors | 1:8997a1b348dd | 120 | } |
Sissors | 1:8997a1b348dd | 121 | if (accelerations[i] > max) { |
Sissors | 1:8997a1b348dd | 122 | max = accelerations[i]; |
Sissors | 1:8997a1b348dd | 123 | retval = 2 * i + 1; |
Sissors | 1:8997a1b348dd | 124 | } |
Sissors | 0:7bc29a9ea016 | 125 | } |
Sissors | 1:8997a1b348dd | 126 | return (MMA7660::Orientation)retval; |
Sissors | 1:8997a1b348dd | 127 | |
Sissors | 1:8997a1b348dd | 128 | |
Sissors | 1:8997a1b348dd | 129 | } |
Sissors | 1:8997a1b348dd | 130 | |
Sissors | 1:8997a1b348dd | 131 | MMA7660::Orientation MMA7660::getSide( void ) |
Sissors | 1:8997a1b348dd | 132 | { |
Sissors | 1:8997a1b348dd | 133 | char tiltreg = read(MMA7660_TILT_R); |
Sissors | 1:8997a1b348dd | 134 | |
Sissors | 1:8997a1b348dd | 135 | //We care about 2 LSBs |
Sissors | 1:8997a1b348dd | 136 | tiltreg &= 0x03; |
Sissors | 1:8997a1b348dd | 137 | if (tiltreg == 0x01) |
Sissors | 1:8997a1b348dd | 138 | return MMA7660::Front; |
Sissors | 1:8997a1b348dd | 139 | if (tiltreg == 0x02) |
Sissors | 1:8997a1b348dd | 140 | return MMA7660::Back; |
Sissors | 1:8997a1b348dd | 141 | return MMA7660::Unknown; |
Sissors | 1:8997a1b348dd | 142 | } |
Sissors | 1:8997a1b348dd | 143 | |
Sissors | 1:8997a1b348dd | 144 | MMA7660::Orientation MMA7660::getOrientation( void ) |
Sissors | 1:8997a1b348dd | 145 | { |
Sissors | 1:8997a1b348dd | 146 | char tiltreg = read(MMA7660_TILT_R); |
Sissors | 1:8997a1b348dd | 147 | |
Sissors | 1:8997a1b348dd | 148 | //We care about bit 2, 3 and 4 (counting from zero) |
Sissors | 1:8997a1b348dd | 149 | tiltreg &= 0x07<<2; |
Sissors | 1:8997a1b348dd | 150 | tiltreg >>= 2; |
Sissors | 1:8997a1b348dd | 151 | if (tiltreg == 0x01) |
Sissors | 1:8997a1b348dd | 152 | return MMA7660::Left; |
Sissors | 1:8997a1b348dd | 153 | if (tiltreg == 0x02) |
Sissors | 1:8997a1b348dd | 154 | return MMA7660::Right; |
Sissors | 1:8997a1b348dd | 155 | if (tiltreg == 0x05) |
Sissors | 1:8997a1b348dd | 156 | return MMA7660::Down; |
Sissors | 1:8997a1b348dd | 157 | if (tiltreg == 0x06) |
Sissors | 1:8997a1b348dd | 158 | return MMA7660::Up; |
Sissors | 1:8997a1b348dd | 159 | return MMA7660::Unknown; |
Sissors | 1:8997a1b348dd | 160 | } |
Sissors | 1:8997a1b348dd | 161 | |
Sissors | 1:8997a1b348dd | 162 | bool MMA7660::isTapped( void ) |
Sissors | 1:8997a1b348dd | 163 | { |
Sissors | 1:8997a1b348dd | 164 | char tiltreg = read(MMA7660_TILT_R); |
Sissors | 0:7bc29a9ea016 | 165 | |
Sissors | 1:8997a1b348dd | 166 | //Tap is bit 5 |
Sissors | 1:8997a1b348dd | 167 | tiltreg >>= 5; |
Sissors | 1:8997a1b348dd | 168 | tiltreg &= 0x01; |
Sissors | 1:8997a1b348dd | 169 | |
Sissors | 1:8997a1b348dd | 170 | return tiltreg==1; |
Sissors | 1:8997a1b348dd | 171 | } |
Sissors | 1:8997a1b348dd | 172 | |
Sissors | 1:8997a1b348dd | 173 | |
Sissors | 1:8997a1b348dd | 174 | ////////////////////////////////////////////// |
Sissors | 1:8997a1b348dd | 175 | ///////////////PRIVATE//////////////////////// |
Sissors | 1:8997a1b348dd | 176 | ////////////////////////////////////////////// |
Sissors | 1:8997a1b348dd | 177 | |
Sissors | 0:7bc29a9ea016 | 178 | |
Sissors | 0:7bc29a9ea016 | 179 | void MMA7660::write(char address, char data) |
Sissors | 0:7bc29a9ea016 | 180 | { |
Sissors | 0:7bc29a9ea016 | 181 | char temp[2]; |
Sissors | 0:7bc29a9ea016 | 182 | temp[0]=address; |
Sissors | 0:7bc29a9ea016 | 183 | temp[1]=data; |
Sissors | 0:7bc29a9ea016 | 184 | |
Sissors | 0:7bc29a9ea016 | 185 | _i2c.write(MMA7660_ADDRESS, temp, 2); |
Sissors | 0:7bc29a9ea016 | 186 | } |
Sissors | 0:7bc29a9ea016 | 187 | |
Sissors | 0:7bc29a9ea016 | 188 | char MMA7660::read(char address) |
Sissors | 0:7bc29a9ea016 | 189 | { |
Sissors | 0:7bc29a9ea016 | 190 | char retval; |
Sissors | 0:7bc29a9ea016 | 191 | _i2c.write(MMA7660_ADDRESS, &address, 1, true); |
Sissors | 0:7bc29a9ea016 | 192 | _i2c.read(MMA7660_ADDRESS, &retval, 1); |
Sissors | 0:7bc29a9ea016 | 193 | return retval; |
Sissors | 0:7bc29a9ea016 | 194 | } |
Sissors | 0:7bc29a9ea016 | 195 | |
Sissors | 0:7bc29a9ea016 | 196 | void MMA7660::read(char address, char *data, int length) |
Sissors | 0:7bc29a9ea016 | 197 | { |
Sissors | 0:7bc29a9ea016 | 198 | _i2c.write(MMA7660_ADDRESS, &address, 1, true); |
Sissors | 0:7bc29a9ea016 | 199 | _i2c.read(MMA7660_ADDRESS, data, length); |
Sissors | 0:7bc29a9ea016 | 200 | } |
Sissors | 0:7bc29a9ea016 | 201 | |
Sissors | 0:7bc29a9ea016 | 202 | float MMA7660::getSingle( int number ) |
Sissors | 0:7bc29a9ea016 | 203 | { |
Sissors | 0:7bc29a9ea016 | 204 | if (!active) { |
Sissors | 0:7bc29a9ea016 | 205 | setActive(true); |
Sissors | 0:7bc29a9ea016 | 206 | active = true; |
Sissors | 1:8997a1b348dd | 207 | wait(0.012 + 1/samplerate); //Wait until new sample is ready |
Sissors | 0:7bc29a9ea016 | 208 | } |
Sissors | 0:7bc29a9ea016 | 209 | |
Sissors | 0:7bc29a9ea016 | 210 | signed char temp; |
Sissors | 0:7bc29a9ea016 | 211 | bool alert; |
Sissors | 0:7bc29a9ea016 | 212 | |
Sissors | 0:7bc29a9ea016 | 213 | do { |
Sissors | 0:7bc29a9ea016 | 214 | alert = false; |
Sissors | 0:7bc29a9ea016 | 215 | temp = read(MMA7660_XOUT_R + number); |
Sissors | 0:7bc29a9ea016 | 216 | if (temp > 63) |
Sissors | 0:7bc29a9ea016 | 217 | alert = true; |
Sissors | 0:7bc29a9ea016 | 218 | if (temp > 31) |
Sissors | 0:7bc29a9ea016 | 219 | temp += 128+64; |
Sissors | 0:7bc29a9ea016 | 220 | } |
Sissors | 0:7bc29a9ea016 | 221 | |
Sissors | 0:7bc29a9ea016 | 222 | while (alert); |
Sissors | 0:7bc29a9ea016 | 223 | |
Sissors | 0:7bc29a9ea016 | 224 | return temp / MMA7660_SENSITIVITY; |
Sissors | 0:7bc29a9ea016 | 225 | } |