Martin Woolley / microbit-dal-bluetooth-mdw

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Fork of microbit-dal by Lancaster University

source/drivers/MicroBitAccelerometer.cpp@38:1a9e8e5e23f2, 2016-07-13 (annotated)

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:18:17 2016 +0100
Revision:
38:1a9e8e5e23f2
Parent:
37:b624ae5e94a5
Child:
39:112df23f039f
Synchronized with git rev b5846f06

Author: Joe Finney

microbit: Fixed unreachable High-G gesture events [issue #109]



Ammended basic gesture recogniser to correclty generate threshold events for

high G forces (3G, 6G and 8G threshold events).



Also refined semantics such that events for any given impulse will be

generated for ALL thresholds below that below. e.g a 7G impulse will now raise

both the 3G and 6G threshold events.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Jonathan Austin 1:8aa5cdb4ab67 1 /*
Jonathan Austin 1:8aa5cdb4ab67 2 The MIT License (MIT)
Jonathan Austin 1:8aa5cdb4ab67 3
Jonathan Austin 1:8aa5cdb4ab67 4 Copyright (c) 2016 British Broadcasting Corporation.
Jonathan Austin 1:8aa5cdb4ab67 5 This software is provided by Lancaster University by arrangement with the BBC.
Jonathan Austin 1:8aa5cdb4ab67 6
Jonathan Austin 1:8aa5cdb4ab67 7 Permission is hereby granted, free of charge, to any person obtaining a
Jonathan Austin 1:8aa5cdb4ab67 8 copy of this software and associated documentation files (the "Software"),
Jonathan Austin 1:8aa5cdb4ab67 9 to deal in the Software without restriction, including without limitation
Jonathan Austin 1:8aa5cdb4ab67 10 the rights to use, copy, modify, merge, publish, distribute, sublicense,
Jonathan Austin 1:8aa5cdb4ab67 11 and/or sell copies of the Software, and to permit persons to whom the
Jonathan Austin 1:8aa5cdb4ab67 12 Software is furnished to do so, subject to the following conditions:
Jonathan Austin 1:8aa5cdb4ab67 13
Jonathan Austin 1:8aa5cdb4ab67 14 The above copyright notice and this permission notice shall be included in
Jonathan Austin 1:8aa5cdb4ab67 15 all copies or substantial portions of the Software.
Jonathan Austin 1:8aa5cdb4ab67 16
Jonathan Austin 1:8aa5cdb4ab67 17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Jonathan Austin 1:8aa5cdb4ab67 18 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Jonathan Austin 1:8aa5cdb4ab67 19 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
Jonathan Austin 1:8aa5cdb4ab67 20 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Jonathan Austin 1:8aa5cdb4ab67 21 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
Jonathan Austin 1:8aa5cdb4ab67 22 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
Jonathan Austin 1:8aa5cdb4ab67 23 DEALINGS IN THE SOFTWARE.
Jonathan Austin 1:8aa5cdb4ab67 24 */
Jonathan Austin 1:8aa5cdb4ab67 25
Jonathan Austin 1:8aa5cdb4ab67 26 /**
Jonathan Austin 1:8aa5cdb4ab67 27 * Class definition for MicroBit Accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 28 *
Jonathan Austin 1:8aa5cdb4ab67 29 * Represents an implementation of the Freescale MMA8653 3 axis accelerometer
Jonathan Austin 1:8aa5cdb4ab67 30 * Also includes basic data caching and on demand activation.
Jonathan Austin 1:8aa5cdb4ab67 31 */
Jonathan Austin 1:8aa5cdb4ab67 32 #include "MicroBitConfig.h"
Jonathan Austin 1:8aa5cdb4ab67 33 #include "MicroBitAccelerometer.h"
Jonathan Austin 1:8aa5cdb4ab67 34 #include "ErrorNo.h"
Jonathan Austin 1:8aa5cdb4ab67 35 #include "MicroBitConfig.h"
Jonathan Austin 1:8aa5cdb4ab67 36 #include "MicroBitEvent.h"
Jonathan Austin 1:8aa5cdb4ab67 37 #include "MicroBitCompat.h"
Jonathan Austin 1:8aa5cdb4ab67 38 #include "MicroBitFiber.h"
Jonathan Austin 1:8aa5cdb4ab67 39
Jonathan Austin 1:8aa5cdb4ab67 40 /**
Jonathan Austin 1:8aa5cdb4ab67 41 * Configures the accelerometer for G range and sample rate defined
Jonathan Austin 1:8aa5cdb4ab67 42 * in this object. The nearest values are chosen to those defined
Jonathan Austin 1:8aa5cdb4ab67 43 * that are supported by the hardware. The instance variables are then
Jonathan Austin 1:8aa5cdb4ab67 44 * updated to reflect reality.
Jonathan Austin 1:8aa5cdb4ab67 45 *
Jonathan Austin 1:8aa5cdb4ab67 46 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if the accelerometer could not be configured.
Jonathan Austin 1:8aa5cdb4ab67 47 */
Jonathan Austin 1:8aa5cdb4ab67 48 int MicroBitAccelerometer::configure()
Jonathan Austin 1:8aa5cdb4ab67 49 {
Jonathan Austin 1:8aa5cdb4ab67 50 const MMA8653SampleRangeConfig *actualSampleRange;
Jonathan Austin 1:8aa5cdb4ab67 51 const MMA8653SampleRateConfig *actualSampleRate;
Jonathan Austin 1:8aa5cdb4ab67 52 int result;
Jonathan Austin 1:8aa5cdb4ab67 53
Jonathan Austin 1:8aa5cdb4ab67 54 // First find the nearest sample rate to that specified.
Jonathan Austin 1:8aa5cdb4ab67 55 actualSampleRate = &MMA8653SampleRate[MMA8653_SAMPLE_RATES-1];
Jonathan Austin 1:8aa5cdb4ab67 56 for (int i=MMA8653_SAMPLE_RATES-1; i>=0; i--)
Jonathan Austin 1:8aa5cdb4ab67 57 {
Jonathan Austin 1:8aa5cdb4ab67 58 if(MMA8653SampleRate[i].sample_period < this->samplePeriod * 1000)
Jonathan Austin 1:8aa5cdb4ab67 59 break;
Jonathan Austin 1:8aa5cdb4ab67 60
Jonathan Austin 1:8aa5cdb4ab67 61 actualSampleRate = &MMA8653SampleRate[i];
Jonathan Austin 1:8aa5cdb4ab67 62 }
Jonathan Austin 1:8aa5cdb4ab67 63
Jonathan Austin 1:8aa5cdb4ab67 64 // Now find the nearest sample range to that specified.
Jonathan Austin 1:8aa5cdb4ab67 65 actualSampleRange = &MMA8653SampleRange[MMA8653_SAMPLE_RANGES-1];
Jonathan Austin 1:8aa5cdb4ab67 66 for (int i=MMA8653_SAMPLE_RANGES-1; i>=0; i--)
Jonathan Austin 1:8aa5cdb4ab67 67 {
Jonathan Austin 1:8aa5cdb4ab67 68 if(MMA8653SampleRange[i].sample_range < this->sampleRange)
Jonathan Austin 1:8aa5cdb4ab67 69 break;
Jonathan Austin 1:8aa5cdb4ab67 70
Jonathan Austin 1:8aa5cdb4ab67 71 actualSampleRange = &MMA8653SampleRange[i];
Jonathan Austin 1:8aa5cdb4ab67 72 }
Jonathan Austin 1:8aa5cdb4ab67 73
Jonathan Austin 1:8aa5cdb4ab67 74 // OK, we have the correct data. Update our local state.
Jonathan Austin 1:8aa5cdb4ab67 75 this->samplePeriod = actualSampleRate->sample_period / 1000;
Jonathan Austin 1:8aa5cdb4ab67 76 this->sampleRange = actualSampleRange->sample_range;
Jonathan Austin 1:8aa5cdb4ab67 77
Jonathan Austin 1:8aa5cdb4ab67 78 // Now configure the accelerometer accordingly.
Jonathan Austin 1:8aa5cdb4ab67 79 // First place the device into standby mode, so it can be configured.
Jonathan Austin 1:8aa5cdb4ab67 80 result = writeCommand(MMA8653_CTRL_REG1, 0x00);
Jonathan Austin 1:8aa5cdb4ab67 81 if (result != 0)
Jonathan Austin 1:8aa5cdb4ab67 82 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 83
Jonathan Austin 1:8aa5cdb4ab67 84 // Enable high precisiosn mode. This consumes a bit more power, but still only 184 uA!
Jonathan Austin 1:8aa5cdb4ab67 85 result = writeCommand(MMA8653_CTRL_REG2, 0x10);
Jonathan Austin 1:8aa5cdb4ab67 86 if (result != 0)
Jonathan Austin 1:8aa5cdb4ab67 87 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 88
Jonathan Austin 1:8aa5cdb4ab67 89 // Enable the INT1 interrupt pin.
Jonathan Austin 1:8aa5cdb4ab67 90 result = writeCommand(MMA8653_CTRL_REG4, 0x01);
Jonathan Austin 1:8aa5cdb4ab67 91 if (result != 0)
Jonathan Austin 1:8aa5cdb4ab67 92 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 93
Jonathan Austin 1:8aa5cdb4ab67 94 // Select the DATA_READY event source to be routed to INT1
Jonathan Austin 1:8aa5cdb4ab67 95 result = writeCommand(MMA8653_CTRL_REG5, 0x01);
Jonathan Austin 1:8aa5cdb4ab67 96 if (result != 0)
Jonathan Austin 1:8aa5cdb4ab67 97 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 98
Jonathan Austin 1:8aa5cdb4ab67 99 // Configure for the selected g range.
Jonathan Austin 1:8aa5cdb4ab67 100 result = writeCommand(MMA8653_XYZ_DATA_CFG, actualSampleRange->xyz_data_cfg);
Jonathan Austin 1:8aa5cdb4ab67 101 if (result != 0)
Jonathan Austin 1:8aa5cdb4ab67 102 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 103
Jonathan Austin 1:8aa5cdb4ab67 104 // Bring the device back online, with 10bit wide samples at the requested frequency.
Jonathan Austin 1:8aa5cdb4ab67 105 result = writeCommand(MMA8653_CTRL_REG1, actualSampleRate->ctrl_reg1 | 0x01);
Jonathan Austin 1:8aa5cdb4ab67 106 if (result != 0)
Jonathan Austin 1:8aa5cdb4ab67 107 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 108
Jonathan Austin 1:8aa5cdb4ab67 109 return MICROBIT_OK;
Jonathan Austin 1:8aa5cdb4ab67 110 }
Jonathan Austin 1:8aa5cdb4ab67 111
Jonathan Austin 1:8aa5cdb4ab67 112 /**
Jonathan Austin 1:8aa5cdb4ab67 113 * Issues a standard, 2 byte I2C command write to the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 114 *
Jonathan Austin 1:8aa5cdb4ab67 115 * Blocks the calling thread until complete.
Jonathan Austin 1:8aa5cdb4ab67 116 *
Jonathan Austin 1:8aa5cdb4ab67 117 * @param reg The address of the register to write to.
Jonathan Austin 1:8aa5cdb4ab67 118 *
Jonathan Austin 1:8aa5cdb4ab67 119 * @param value The value to write.
Jonathan Austin 1:8aa5cdb4ab67 120 *
Jonathan Austin 1:8aa5cdb4ab67 121 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if the the write request failed.
Jonathan Austin 1:8aa5cdb4ab67 122 */
Jonathan Austin 1:8aa5cdb4ab67 123 int MicroBitAccelerometer::writeCommand(uint8_t reg, uint8_t value)
Jonathan Austin 1:8aa5cdb4ab67 124 {
Jonathan Austin 1:8aa5cdb4ab67 125 uint8_t command[2];
Jonathan Austin 1:8aa5cdb4ab67 126 command[0] = reg;
Jonathan Austin 1:8aa5cdb4ab67 127 command[1] = value;
Jonathan Austin 1:8aa5cdb4ab67 128
Jonathan Austin 1:8aa5cdb4ab67 129 return i2c.write(address, (const char *)command, 2);
Jonathan Austin 1:8aa5cdb4ab67 130 }
Jonathan Austin 1:8aa5cdb4ab67 131
Jonathan Austin 1:8aa5cdb4ab67 132 /**
Jonathan Austin 1:8aa5cdb4ab67 133 * Issues a read command, copying data into the specified buffer.
Jonathan Austin 1:8aa5cdb4ab67 134 *
Jonathan Austin 1:8aa5cdb4ab67 135 * Blocks the calling thread until complete.
Jonathan Austin 1:8aa5cdb4ab67 136 *
Jonathan Austin 1:8aa5cdb4ab67 137 * @param reg The address of the register to access.
Jonathan Austin 1:8aa5cdb4ab67 138 *
Jonathan Austin 1:8aa5cdb4ab67 139 * @param buffer Memory area to read the data into.
Jonathan Austin 1:8aa5cdb4ab67 140 *
Jonathan Austin 1:8aa5cdb4ab67 141 * @param length The number of bytes to read.
Jonathan Austin 1:8aa5cdb4ab67 142 *
Jonathan Austin 1:8aa5cdb4ab67 143 * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER or MICROBIT_I2C_ERROR if the the read request failed.
Jonathan Austin 1:8aa5cdb4ab67 144 */
Jonathan Austin 1:8aa5cdb4ab67 145 int MicroBitAccelerometer::readCommand(uint8_t reg, uint8_t* buffer, int length)
Jonathan Austin 1:8aa5cdb4ab67 146 {
Jonathan Austin 1:8aa5cdb4ab67 147 int result;
Jonathan Austin 1:8aa5cdb4ab67 148
Jonathan Austin 1:8aa5cdb4ab67 149 if (buffer == NULL || length <= 0 )
Jonathan Austin 1:8aa5cdb4ab67 150 return MICROBIT_INVALID_PARAMETER;
Jonathan Austin 1:8aa5cdb4ab67 151
Jonathan Austin 1:8aa5cdb4ab67 152 result = i2c.write(address, (const char *)&reg, 1, true);
Jonathan Austin 1:8aa5cdb4ab67 153 if (result !=0)
Jonathan Austin 1:8aa5cdb4ab67 154 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 155
Jonathan Austin 1:8aa5cdb4ab67 156 result = i2c.read(address, (char *)buffer, length);
Jonathan Austin 1:8aa5cdb4ab67 157 if (result !=0)
Jonathan Austin 1:8aa5cdb4ab67 158 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 159
Jonathan Austin 1:8aa5cdb4ab67 160 return MICROBIT_OK;
Jonathan Austin 1:8aa5cdb4ab67 161 }
Jonathan Austin 1:8aa5cdb4ab67 162
Jonathan Austin 1:8aa5cdb4ab67 163 /**
Jonathan Austin 1:8aa5cdb4ab67 164 * Constructor.
Jonathan Austin 1:8aa5cdb4ab67 165 * Create a software abstraction of an accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 166 *
Jonathan Austin 1:8aa5cdb4ab67 167 * @param _i2c an instance of MicroBitI2C used to communicate with the onboard accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 168 *
Jonathan Austin 1:8aa5cdb4ab67 169 * @param address the default I2C address of the accelerometer. Defaults to: MMA8653_DEFAULT_ADDR.
Jonathan Austin 1:8aa5cdb4ab67 170 *
Jonathan Austin 1:8aa5cdb4ab67 171 * @param id the unique EventModel id of this component. Defaults to: MICROBIT_ID_ACCELEROMETER
Jonathan Austin 1:8aa5cdb4ab67 172 *
Jonathan Austin 1:8aa5cdb4ab67 173 * @code
Jonathan Austin 1:8aa5cdb4ab67 174 * MicroBitI2C i2c = MicroBitI2C(I2C_SDA0, I2C_SCL0);
Jonathan Austin 1:8aa5cdb4ab67 175 *
Jonathan Austin 1:8aa5cdb4ab67 176 * MicroBitAccelerometer accelerometer = MicroBitAccelerometer(i2c);
Jonathan Austin 1:8aa5cdb4ab67 177 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 178 */
Jonathan Austin 1:8aa5cdb4ab67 179 MicroBitAccelerometer::MicroBitAccelerometer(MicroBitI2C& _i2c, uint16_t address, uint16_t id) : sample(), int1(MICROBIT_PIN_ACCEL_DATA_READY), i2c(_i2c)
Jonathan Austin 1:8aa5cdb4ab67 180 {
Jonathan Austin 1:8aa5cdb4ab67 181 // Store our identifiers.
Jonathan Austin 1:8aa5cdb4ab67 182 this->id = id;
Jonathan Austin 1:8aa5cdb4ab67 183 this->status = 0;
Jonathan Austin 1:8aa5cdb4ab67 184 this->address = address;
Jonathan Austin 1:8aa5cdb4ab67 185
Jonathan Austin 1:8aa5cdb4ab67 186 // Update our internal state for 50Hz at +/- 2g (50Hz has a period af 20ms).
Jonathan Austin 1:8aa5cdb4ab67 187 this->samplePeriod = 20;
Jonathan Austin 1:8aa5cdb4ab67 188 this->sampleRange = 2;
Jonathan Austin 1:8aa5cdb4ab67 189
Jonathan Austin 1:8aa5cdb4ab67 190 // Initialise gesture history
Jonathan Austin 1:8aa5cdb4ab67 191 this->sigma = 0;
LancasterUniversity 38:1a9e8e5e23f2 192 this->impulseSigma = 0;
Jonathan Austin 1:8aa5cdb4ab67 193 this->lastGesture = GESTURE_NONE;
Jonathan Austin 1:8aa5cdb4ab67 194 this->currentGesture = GESTURE_NONE;
Jonathan Austin 1:8aa5cdb4ab67 195 this->shake.x = 0;
Jonathan Austin 1:8aa5cdb4ab67 196 this->shake.y = 0;
Jonathan Austin 1:8aa5cdb4ab67 197 this->shake.z = 0;
Jonathan Austin 1:8aa5cdb4ab67 198 this->shake.count = 0;
Jonathan Austin 1:8aa5cdb4ab67 199 this->shake.timer = 0;
LancasterUniversity 38:1a9e8e5e23f2 200 this->shake.tap = 1;
LancasterUniversity 38:1a9e8e5e23f2 201 this->shake.impulse_3 = 1;
LancasterUniversity 38:1a9e8e5e23f2 202 this->shake.impulse_6 = 1;
LancasterUniversity 38:1a9e8e5e23f2 203 this->shake.impulse_8 = 1;
Jonathan Austin 1:8aa5cdb4ab67 204
Jonathan Austin 1:8aa5cdb4ab67 205 // Configure and enable the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 206 if (this->configure() == MICROBIT_OK)
Jonathan Austin 1:8aa5cdb4ab67 207 status |= MICROBIT_COMPONENT_RUNNING;
Jonathan Austin 1:8aa5cdb4ab67 208 }
Jonathan Austin 1:8aa5cdb4ab67 209
Jonathan Austin 1:8aa5cdb4ab67 210 /**
Jonathan Austin 1:8aa5cdb4ab67 211 * Attempts to read the 8 bit ID from the accelerometer, this can be used for
Jonathan Austin 1:8aa5cdb4ab67 212 * validation purposes.
Jonathan Austin 1:8aa5cdb4ab67 213 *
Jonathan Austin 1:8aa5cdb4ab67 214 * @return the 8 bit ID returned by the accelerometer, or MICROBIT_I2C_ERROR if the request fails.
Jonathan Austin 1:8aa5cdb4ab67 215 *
Jonathan Austin 1:8aa5cdb4ab67 216 * @code
Jonathan Austin 1:8aa5cdb4ab67 217 * accelerometer.whoAmI();
Jonathan Austin 1:8aa5cdb4ab67 218 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 219 */
Jonathan Austin 1:8aa5cdb4ab67 220 int MicroBitAccelerometer::whoAmI()
Jonathan Austin 1:8aa5cdb4ab67 221 {
Jonathan Austin 1:8aa5cdb4ab67 222 uint8_t data;
Jonathan Austin 1:8aa5cdb4ab67 223 int result;
Jonathan Austin 1:8aa5cdb4ab67 224
Jonathan Austin 1:8aa5cdb4ab67 225 result = readCommand(MMA8653_WHOAMI, &data, 1);
Jonathan Austin 1:8aa5cdb4ab67 226 if (result !=0)
Jonathan Austin 1:8aa5cdb4ab67 227 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 228
Jonathan Austin 1:8aa5cdb4ab67 229 return (int)data;
Jonathan Austin 1:8aa5cdb4ab67 230 }
Jonathan Austin 1:8aa5cdb4ab67 231
Jonathan Austin 1:8aa5cdb4ab67 232 /**
Jonathan Austin 1:8aa5cdb4ab67 233 * Reads the acceleration data from the accelerometer, and stores it in our buffer.
Jonathan Austin 1:8aa5cdb4ab67 234 * This only happens if the accelerometer indicates that it has new data via int1.
Jonathan Austin 1:8aa5cdb4ab67 235 *
Jonathan Austin 1:8aa5cdb4ab67 236 * On first use, this member function will attempt to add this component to the
Jonathan Austin 1:8aa5cdb4ab67 237 * list of fiber components in order to constantly update the values stored
Jonathan Austin 1:8aa5cdb4ab67 238 * by this object.
Jonathan Austin 1:8aa5cdb4ab67 239 *
Jonathan Austin 1:8aa5cdb4ab67 240 * This technique is called lazy instantiation, and it means that we do not
Jonathan Austin 1:8aa5cdb4ab67 241 * obtain the overhead from non-chalantly adding this component to fiber components.
Jonathan Austin 1:8aa5cdb4ab67 242 *
Jonathan Austin 1:8aa5cdb4ab67 243 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if the read request fails.
Jonathan Austin 1:8aa5cdb4ab67 244 */
Jonathan Austin 1:8aa5cdb4ab67 245 int MicroBitAccelerometer::updateSample()
Jonathan Austin 1:8aa5cdb4ab67 246 {
Jonathan Austin 1:8aa5cdb4ab67 247 if(!(status & MICROBIT_ACCEL_ADDED_TO_IDLE))
Jonathan Austin 1:8aa5cdb4ab67 248 {
Jonathan Austin 1:8aa5cdb4ab67 249 fiber_add_idle_component(this);
Jonathan Austin 1:8aa5cdb4ab67 250 status |= MICROBIT_ACCEL_ADDED_TO_IDLE;
Jonathan Austin 1:8aa5cdb4ab67 251 }
Jonathan Austin 1:8aa5cdb4ab67 252
Jonathan Austin 1:8aa5cdb4ab67 253 // Poll interrupt line from accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 254 // n.b. Default is Active LO. Interrupt is cleared in data read.
Jonathan Austin 1:8aa5cdb4ab67 255 if(!int1)
Jonathan Austin 1:8aa5cdb4ab67 256 {
Jonathan Austin 1:8aa5cdb4ab67 257 int8_t data[6];
Jonathan Austin 1:8aa5cdb4ab67 258 int result;
Jonathan Austin 1:8aa5cdb4ab67 259
Jonathan Austin 1:8aa5cdb4ab67 260 result = readCommand(MMA8653_OUT_X_MSB, (uint8_t *)data, 6);
Jonathan Austin 1:8aa5cdb4ab67 261 if (result !=0)
Jonathan Austin 1:8aa5cdb4ab67 262 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 263
Jonathan Austin 1:8aa5cdb4ab67 264 // read MSB values...
Jonathan Austin 1:8aa5cdb4ab67 265 sample.x = data[0];
Jonathan Austin 1:8aa5cdb4ab67 266 sample.y = data[2];
Jonathan Austin 1:8aa5cdb4ab67 267 sample.z = data[4];
Jonathan Austin 1:8aa5cdb4ab67 268
Jonathan Austin 1:8aa5cdb4ab67 269 // Normalize the data in the 0..1024 range.
Jonathan Austin 1:8aa5cdb4ab67 270 sample.x *= 8;
Jonathan Austin 1:8aa5cdb4ab67 271 sample.y *= 8;
Jonathan Austin 1:8aa5cdb4ab67 272 sample.z *= 8;
Jonathan Austin 1:8aa5cdb4ab67 273
Jonathan Austin 1:8aa5cdb4ab67 274 #if CONFIG_ENABLED(USE_ACCEL_LSB)
Jonathan Austin 1:8aa5cdb4ab67 275 // Add in LSB values.
Jonathan Austin 1:8aa5cdb4ab67 276 sample.x += (data[1] / 64);
Jonathan Austin 1:8aa5cdb4ab67 277 sample.y += (data[3] / 64);
Jonathan Austin 1:8aa5cdb4ab67 278 sample.z += (data[5] / 64);
Jonathan Austin 1:8aa5cdb4ab67 279 #endif
Jonathan Austin 1:8aa5cdb4ab67 280
Jonathan Austin 1:8aa5cdb4ab67 281 // Scale into millig (approx!)
Jonathan Austin 1:8aa5cdb4ab67 282 sample.x *= this->sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 283 sample.y *= this->sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 284 sample.z *= this->sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 285
Jonathan Austin 1:8aa5cdb4ab67 286 // Indicate that pitch and roll data is now stale, and needs to be recalculated if needed.
Jonathan Austin 1:8aa5cdb4ab67 287 status &= ~MICROBIT_ACCEL_PITCH_ROLL_VALID;
Jonathan Austin 1:8aa5cdb4ab67 288
Jonathan Austin 1:8aa5cdb4ab67 289 // Update gesture tracking
Jonathan Austin 1:8aa5cdb4ab67 290 updateGesture();
Jonathan Austin 1:8aa5cdb4ab67 291
Jonathan Austin 1:8aa5cdb4ab67 292 // Indicate that a new sample is available
Jonathan Austin 1:8aa5cdb4ab67 293 MicroBitEvent e(id, MICROBIT_ACCELEROMETER_EVT_DATA_UPDATE);
Jonathan Austin 1:8aa5cdb4ab67 294 }
Jonathan Austin 1:8aa5cdb4ab67 295
Jonathan Austin 1:8aa5cdb4ab67 296 return MICROBIT_OK;
Jonathan Austin 1:8aa5cdb4ab67 297 };
Jonathan Austin 1:8aa5cdb4ab67 298
Jonathan Austin 1:8aa5cdb4ab67 299 /**
Jonathan Austin 1:8aa5cdb4ab67 300 * A service function.
Jonathan Austin 1:8aa5cdb4ab67 301 * It calculates the current scalar acceleration of the device (x^2 + y^2 + z^2).
Jonathan Austin 1:8aa5cdb4ab67 302 * It does not, however, square root the result, as this is a relatively high cost operation.
Jonathan Austin 1:8aa5cdb4ab67 303 *
Jonathan Austin 1:8aa5cdb4ab67 304 * This is left to application code should it be needed.
Jonathan Austin 1:8aa5cdb4ab67 305 *
Jonathan Austin 1:8aa5cdb4ab67 306 * @return the sum of the square of the acceleration of the device across all axes.
Jonathan Austin 1:8aa5cdb4ab67 307 */
Jonathan Austin 1:8aa5cdb4ab67 308 int MicroBitAccelerometer::instantaneousAccelerationSquared()
Jonathan Austin 1:8aa5cdb4ab67 309 {
Jonathan Austin 1:8aa5cdb4ab67 310 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 311
Jonathan Austin 1:8aa5cdb4ab67 312 // Use pythagoras theorem to determine the combined force acting on the device.
Jonathan Austin 1:8aa5cdb4ab67 313 return (int)sample.x*(int)sample.x + (int)sample.y*(int)sample.y + (int)sample.z*(int)sample.z;
Jonathan Austin 1:8aa5cdb4ab67 314 }
Jonathan Austin 1:8aa5cdb4ab67 315
Jonathan Austin 1:8aa5cdb4ab67 316 /**
Jonathan Austin 1:8aa5cdb4ab67 317 * Service function.
Jonathan Austin 1:8aa5cdb4ab67 318 * Determines a 'best guess' posture of the device based on instantaneous data.
Jonathan Austin 1:8aa5cdb4ab67 319 *
LancasterUniversity 37:b624ae5e94a5 320 * This makes no use of historic data, and forms the input to the filter implemented in updateGesture().
Jonathan Austin 1:8aa5cdb4ab67 321 *
Jonathan Austin 1:8aa5cdb4ab67 322 * @return A 'best guess' of the current posture of the device, based on instanataneous data.
Jonathan Austin 1:8aa5cdb4ab67 323 */
Jonathan Austin 1:8aa5cdb4ab67 324 BasicGesture MicroBitAccelerometer::instantaneousPosture()
Jonathan Austin 1:8aa5cdb4ab67 325 {
Jonathan Austin 1:8aa5cdb4ab67 326 bool shakeDetected = false;
Jonathan Austin 1:8aa5cdb4ab67 327
LancasterUniversity 38:1a9e8e5e23f2 328
Jonathan Austin 1:8aa5cdb4ab67 329 // Test for shake events.
Jonathan Austin 1:8aa5cdb4ab67 330 // We detect a shake by measuring zero crossings in each axis. In other words, if we see a strong acceleration to the left followed by
LancasterUniversity 37:b624ae5e94a5 331 // a strong acceleration to the right, then we can infer a shake. Similarly, we can do this for each axis (left/right, up/down, in/out).
Jonathan Austin 1:8aa5cdb4ab67 332 //
Jonathan Austin 1:8aa5cdb4ab67 333 // If we see enough zero crossings in succession (MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD), then we decide that the device
Jonathan Austin 1:8aa5cdb4ab67 334 // has been shaken.
Jonathan Austin 1:8aa5cdb4ab67 335 if ((getX() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.x) || (getX() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.x))
Jonathan Austin 1:8aa5cdb4ab67 336 {
Jonathan Austin 1:8aa5cdb4ab67 337 shakeDetected = true;
Jonathan Austin 1:8aa5cdb4ab67 338 shake.x = !shake.x;
Jonathan Austin 1:8aa5cdb4ab67 339 }
Jonathan Austin 1:8aa5cdb4ab67 340
Jonathan Austin 1:8aa5cdb4ab67 341 if ((getY() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.y) || (getY() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.y))
Jonathan Austin 1:8aa5cdb4ab67 342 {
Jonathan Austin 1:8aa5cdb4ab67 343 shakeDetected = true;
Jonathan Austin 1:8aa5cdb4ab67 344 shake.y = !shake.y;
Jonathan Austin 1:8aa5cdb4ab67 345 }
Jonathan Austin 1:8aa5cdb4ab67 346
Jonathan Austin 1:8aa5cdb4ab67 347 if ((getZ() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.z) || (getZ() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.z))
Jonathan Austin 1:8aa5cdb4ab67 348 {
Jonathan Austin 1:8aa5cdb4ab67 349 shakeDetected = true;
Jonathan Austin 1:8aa5cdb4ab67 350 shake.z = !shake.z;
Jonathan Austin 1:8aa5cdb4ab67 351 }
Jonathan Austin 1:8aa5cdb4ab67 352
Jonathan Austin 1:8aa5cdb4ab67 353 if (shakeDetected && shake.count < MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD && ++shake.count == MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD)
Jonathan Austin 1:8aa5cdb4ab67 354 shake.shaken = 1;
Jonathan Austin 1:8aa5cdb4ab67 355
Jonathan Austin 1:8aa5cdb4ab67 356 if (++shake.timer >= MICROBIT_ACCELEROMETER_SHAKE_DAMPING)
Jonathan Austin 1:8aa5cdb4ab67 357 {
Jonathan Austin 1:8aa5cdb4ab67 358 shake.timer = 0;
Jonathan Austin 1:8aa5cdb4ab67 359 if (shake.count > 0)
Jonathan Austin 1:8aa5cdb4ab67 360 {
Jonathan Austin 1:8aa5cdb4ab67 361 if(--shake.count == 0)
Jonathan Austin 1:8aa5cdb4ab67 362 shake.shaken = 0;
Jonathan Austin 1:8aa5cdb4ab67 363 }
Jonathan Austin 1:8aa5cdb4ab67 364 }
Jonathan Austin 1:8aa5cdb4ab67 365
LancasterUniversity 38:1a9e8e5e23f2 366 // Shake events take the highest priority, as under high levels of change, other events
LancasterUniversity 38:1a9e8e5e23f2 367 // are likely to be transient.
Jonathan Austin 1:8aa5cdb4ab67 368 if (shake.shaken)
Jonathan Austin 1:8aa5cdb4ab67 369 return GESTURE_SHAKE;
Jonathan Austin 1:8aa5cdb4ab67 370
Jonathan Austin 1:8aa5cdb4ab67 371 // Determine our posture.
Jonathan Austin 1:8aa5cdb4ab67 372 if (getX() < (-1000 + MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 373 return GESTURE_LEFT;
Jonathan Austin 1:8aa5cdb4ab67 374
Jonathan Austin 1:8aa5cdb4ab67 375 if (getX() > (1000 - MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 376 return GESTURE_RIGHT;
Jonathan Austin 1:8aa5cdb4ab67 377
Jonathan Austin 1:8aa5cdb4ab67 378 if (getY() < (-1000 + MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 379 return GESTURE_DOWN;
Jonathan Austin 1:8aa5cdb4ab67 380
Jonathan Austin 1:8aa5cdb4ab67 381 if (getY() > (1000 - MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 382 return GESTURE_UP;
Jonathan Austin 1:8aa5cdb4ab67 383
Jonathan Austin 1:8aa5cdb4ab67 384 if (getZ() < (-1000 + MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 385 return GESTURE_FACE_UP;
Jonathan Austin 1:8aa5cdb4ab67 386
Jonathan Austin 1:8aa5cdb4ab67 387 if (getZ() > (1000 - MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 388 return GESTURE_FACE_DOWN;
Jonathan Austin 1:8aa5cdb4ab67 389
Jonathan Austin 1:8aa5cdb4ab67 390 return GESTURE_NONE;
Jonathan Austin 1:8aa5cdb4ab67 391 }
Jonathan Austin 1:8aa5cdb4ab67 392
Jonathan Austin 1:8aa5cdb4ab67 393 /**
Jonathan Austin 1:8aa5cdb4ab67 394 * Updates the basic gesture recognizer. This performs instantaneous pose recognition, and also some low pass filtering to promote
Jonathan Austin 1:8aa5cdb4ab67 395 * stability.
Jonathan Austin 1:8aa5cdb4ab67 396 */
Jonathan Austin 1:8aa5cdb4ab67 397 void MicroBitAccelerometer::updateGesture()
Jonathan Austin 1:8aa5cdb4ab67 398 {
LancasterUniversity 38:1a9e8e5e23f2 399 // Check for High/Low G force events - typically impulses, impacts etc.
LancasterUniversity 38:1a9e8e5e23f2 400 // Again, during such spikes, these event take priority of the posture of the device.
LancasterUniversity 38:1a9e8e5e23f2 401 // For these events, we don't perform any low pass filtering.
LancasterUniversity 38:1a9e8e5e23f2 402 int force = instantaneousAccelerationSquared();
LancasterUniversity 38:1a9e8e5e23f2 403
LancasterUniversity 38:1a9e8e5e23f2 404 if (force > MICROBIT_ACCELEROMETER_3G_THRESHOLD)
LancasterUniversity 38:1a9e8e5e23f2 405 {
LancasterUniversity 38:1a9e8e5e23f2 406 if (force > MICROBIT_ACCELEROMETER_3G_THRESHOLD && !shake.impulse_3)
LancasterUniversity 38:1a9e8e5e23f2 407 {
LancasterUniversity 38:1a9e8e5e23f2 408 MicroBitEvent e(MICROBIT_ID_GESTURE, GESTURE_3G);
LancasterUniversity 38:1a9e8e5e23f2 409 shake.impulse_3 = 1;
LancasterUniversity 38:1a9e8e5e23f2 410 }
LancasterUniversity 38:1a9e8e5e23f2 411 if (force > MICROBIT_ACCELEROMETER_6G_THRESHOLD && !shake.impulse_6)
LancasterUniversity 38:1a9e8e5e23f2 412 {
LancasterUniversity 38:1a9e8e5e23f2 413 MicroBitEvent e(MICROBIT_ID_GESTURE, GESTURE_6G);
LancasterUniversity 38:1a9e8e5e23f2 414 shake.impulse_6 = 1;
LancasterUniversity 38:1a9e8e5e23f2 415 }
LancasterUniversity 38:1a9e8e5e23f2 416 if (force > MICROBIT_ACCELEROMETER_8G_THRESHOLD && !shake.impulse_8)
LancasterUniversity 38:1a9e8e5e23f2 417 {
LancasterUniversity 38:1a9e8e5e23f2 418 MicroBitEvent e(MICROBIT_ID_GESTURE, GESTURE_8G);
LancasterUniversity 38:1a9e8e5e23f2 419 shake.impulse_8 = 1;
LancasterUniversity 38:1a9e8e5e23f2 420 }
LancasterUniversity 38:1a9e8e5e23f2 421
LancasterUniversity 38:1a9e8e5e23f2 422 impulseSigma = 0;
LancasterUniversity 38:1a9e8e5e23f2 423 }
LancasterUniversity 38:1a9e8e5e23f2 424
LancasterUniversity 38:1a9e8e5e23f2 425 // Reset the impulse event onve the acceleration has subsided.
LancasterUniversity 38:1a9e8e5e23f2 426 if (impulseSigma < MICROBIT_ACCELEROMETER_GESTURE_DAMPING)
LancasterUniversity 38:1a9e8e5e23f2 427 impulseSigma++;
LancasterUniversity 38:1a9e8e5e23f2 428 else
LancasterUniversity 38:1a9e8e5e23f2 429 shake.impulse_3 = shake.impulse_6 = shake.impulse_8 = 0;
LancasterUniversity 38:1a9e8e5e23f2 430
LancasterUniversity 38:1a9e8e5e23f2 431
Jonathan Austin 1:8aa5cdb4ab67 432 // Determine what it looks like we're doing based on the latest sample...
Jonathan Austin 1:8aa5cdb4ab67 433 BasicGesture g = instantaneousPosture();
Jonathan Austin 1:8aa5cdb4ab67 434
Jonathan Austin 1:8aa5cdb4ab67 435 // Perform some low pass filtering to reduce jitter from any detected effects
Jonathan Austin 1:8aa5cdb4ab67 436 if (g == currentGesture)
Jonathan Austin 1:8aa5cdb4ab67 437 {
Jonathan Austin 1:8aa5cdb4ab67 438 if (sigma < MICROBIT_ACCELEROMETER_GESTURE_DAMPING)
Jonathan Austin 1:8aa5cdb4ab67 439 sigma++;
Jonathan Austin 1:8aa5cdb4ab67 440 }
Jonathan Austin 1:8aa5cdb4ab67 441 else
Jonathan Austin 1:8aa5cdb4ab67 442 {
Jonathan Austin 1:8aa5cdb4ab67 443 currentGesture = g;
Jonathan Austin 1:8aa5cdb4ab67 444 sigma = 0;
Jonathan Austin 1:8aa5cdb4ab67 445 }
Jonathan Austin 1:8aa5cdb4ab67 446
Jonathan Austin 1:8aa5cdb4ab67 447 // If we've reached threshold, update our record and raise the relevant event...
Jonathan Austin 1:8aa5cdb4ab67 448 if (currentGesture != lastGesture && sigma >= MICROBIT_ACCELEROMETER_GESTURE_DAMPING)
Jonathan Austin 1:8aa5cdb4ab67 449 {
Jonathan Austin 1:8aa5cdb4ab67 450 lastGesture = currentGesture;
Jonathan Austin 1:8aa5cdb4ab67 451 MicroBitEvent e(MICROBIT_ID_GESTURE, lastGesture);
Jonathan Austin 1:8aa5cdb4ab67 452 }
Jonathan Austin 1:8aa5cdb4ab67 453 }
Jonathan Austin 1:8aa5cdb4ab67 454
Jonathan Austin 1:8aa5cdb4ab67 455 /**
Jonathan Austin 1:8aa5cdb4ab67 456 * Attempts to set the sample rate of the accelerometer to the specified value (in ms).
Jonathan Austin 1:8aa5cdb4ab67 457 *
Jonathan Austin 1:8aa5cdb4ab67 458 * @param period the requested time between samples, in milliseconds.
Jonathan Austin 1:8aa5cdb4ab67 459 *
Jonathan Austin 1:8aa5cdb4ab67 460 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR is the request fails.
Jonathan Austin 1:8aa5cdb4ab67 461 *
Jonathan Austin 1:8aa5cdb4ab67 462 * @code
Jonathan Austin 1:8aa5cdb4ab67 463 * // sample rate is now 20 ms.
Jonathan Austin 1:8aa5cdb4ab67 464 * accelerometer.setPeriod(20);
Jonathan Austin 1:8aa5cdb4ab67 465 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 466 *
Jonathan Austin 1:8aa5cdb4ab67 467 * @note The requested rate may not be possible on the hardware. In this case, the
Jonathan Austin 1:8aa5cdb4ab67 468 * nearest lower rate is chosen.
Jonathan Austin 1:8aa5cdb4ab67 469 */
Jonathan Austin 1:8aa5cdb4ab67 470 int MicroBitAccelerometer::setPeriod(int period)
Jonathan Austin 1:8aa5cdb4ab67 471 {
Jonathan Austin 1:8aa5cdb4ab67 472 this->samplePeriod = period;
Jonathan Austin 1:8aa5cdb4ab67 473 return this->configure();
Jonathan Austin 1:8aa5cdb4ab67 474 }
Jonathan Austin 1:8aa5cdb4ab67 475
Jonathan Austin 1:8aa5cdb4ab67 476 /**
Jonathan Austin 1:8aa5cdb4ab67 477 * Reads the currently configured sample rate of the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 478 *
Jonathan Austin 1:8aa5cdb4ab67 479 * @return The time between samples, in milliseconds.
Jonathan Austin 1:8aa5cdb4ab67 480 */
Jonathan Austin 1:8aa5cdb4ab67 481 int MicroBitAccelerometer::getPeriod()
Jonathan Austin 1:8aa5cdb4ab67 482 {
Jonathan Austin 1:8aa5cdb4ab67 483 return (int)samplePeriod;
Jonathan Austin 1:8aa5cdb4ab67 484 }
Jonathan Austin 1:8aa5cdb4ab67 485
Jonathan Austin 1:8aa5cdb4ab67 486 /**
Jonathan Austin 1:8aa5cdb4ab67 487 * Attempts to set the sample range of the accelerometer to the specified value (in g).
Jonathan Austin 1:8aa5cdb4ab67 488 *
Jonathan Austin 1:8aa5cdb4ab67 489 * @param range The requested sample range of samples, in g.
Jonathan Austin 1:8aa5cdb4ab67 490 *
Jonathan Austin 1:8aa5cdb4ab67 491 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR is the request fails.
Jonathan Austin 1:8aa5cdb4ab67 492 *
Jonathan Austin 1:8aa5cdb4ab67 493 * @code
Jonathan Austin 1:8aa5cdb4ab67 494 * // the sample range of the accelerometer is now 8G.
Jonathan Austin 1:8aa5cdb4ab67 495 * accelerometer.setRange(8);
Jonathan Austin 1:8aa5cdb4ab67 496 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 497 *
Jonathan Austin 1:8aa5cdb4ab67 498 * @note The requested range may not be possible on the hardware. In this case, the
Jonathan Austin 1:8aa5cdb4ab67 499 * nearest lower range is chosen.
Jonathan Austin 1:8aa5cdb4ab67 500 */
Jonathan Austin 1:8aa5cdb4ab67 501 int MicroBitAccelerometer::setRange(int range)
Jonathan Austin 1:8aa5cdb4ab67 502 {
Jonathan Austin 1:8aa5cdb4ab67 503 this->sampleRange = range;
Jonathan Austin 1:8aa5cdb4ab67 504 return this->configure();
Jonathan Austin 1:8aa5cdb4ab67 505 }
Jonathan Austin 1:8aa5cdb4ab67 506
Jonathan Austin 1:8aa5cdb4ab67 507 /**
Jonathan Austin 1:8aa5cdb4ab67 508 * Reads the currently configured sample range of the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 509 *
Jonathan Austin 1:8aa5cdb4ab67 510 * @return The sample range, in g.
Jonathan Austin 1:8aa5cdb4ab67 511 */
Jonathan Austin 1:8aa5cdb4ab67 512 int MicroBitAccelerometer::getRange()
Jonathan Austin 1:8aa5cdb4ab67 513 {
Jonathan Austin 1:8aa5cdb4ab67 514 return (int)sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 515 }
Jonathan Austin 1:8aa5cdb4ab67 516
Jonathan Austin 1:8aa5cdb4ab67 517 /**
Jonathan Austin 1:8aa5cdb4ab67 518 * Reads the value of the X axis from the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 519 *
Jonathan Austin 1:8aa5cdb4ab67 520 * @param system The coordinate system to use. By default, a simple cartesian system is provided.
Jonathan Austin 1:8aa5cdb4ab67 521 *
Jonathan Austin 1:8aa5cdb4ab67 522 * @return The force measured in the X axis, in milli-g.
Jonathan Austin 1:8aa5cdb4ab67 523 *
Jonathan Austin 1:8aa5cdb4ab67 524 * @code
Jonathan Austin 1:8aa5cdb4ab67 525 * accelerometer.getX();
Jonathan Austin 1:8aa5cdb4ab67 526 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 527 */
Jonathan Austin 1:8aa5cdb4ab67 528 int MicroBitAccelerometer::getX(MicroBitCoordinateSystem system)
Jonathan Austin 1:8aa5cdb4ab67 529 {
Jonathan Austin 1:8aa5cdb4ab67 530 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 531
Jonathan Austin 1:8aa5cdb4ab67 532 switch (system)
Jonathan Austin 1:8aa5cdb4ab67 533 {
Jonathan Austin 1:8aa5cdb4ab67 534 case SIMPLE_CARTESIAN:
Jonathan Austin 1:8aa5cdb4ab67 535 return -sample.x;
Jonathan Austin 1:8aa5cdb4ab67 536
Jonathan Austin 1:8aa5cdb4ab67 537 case NORTH_EAST_DOWN:
Jonathan Austin 1:8aa5cdb4ab67 538 return sample.y;
Jonathan Austin 1:8aa5cdb4ab67 539
Jonathan Austin 1:8aa5cdb4ab67 540 case RAW:
Jonathan Austin 1:8aa5cdb4ab67 541 default:
Jonathan Austin 1:8aa5cdb4ab67 542 return sample.x;
Jonathan Austin 1:8aa5cdb4ab67 543 }
Jonathan Austin 1:8aa5cdb4ab67 544 }
Jonathan Austin 1:8aa5cdb4ab67 545
Jonathan Austin 1:8aa5cdb4ab67 546 /**
Jonathan Austin 1:8aa5cdb4ab67 547 * Reads the value of the Y axis from the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 548 *
Jonathan Austin 1:8aa5cdb4ab67 549 * @return The force measured in the Y axis, in milli-g.
Jonathan Austin 1:8aa5cdb4ab67 550 *
Jonathan Austin 1:8aa5cdb4ab67 551 * @code
Jonathan Austin 1:8aa5cdb4ab67 552 * accelerometer.getY();
Jonathan Austin 1:8aa5cdb4ab67 553 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 554 */
Jonathan Austin 1:8aa5cdb4ab67 555 int MicroBitAccelerometer::getY(MicroBitCoordinateSystem system)
Jonathan Austin 1:8aa5cdb4ab67 556 {
Jonathan Austin 1:8aa5cdb4ab67 557 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 558
Jonathan Austin 1:8aa5cdb4ab67 559 switch (system)
Jonathan Austin 1:8aa5cdb4ab67 560 {
Jonathan Austin 1:8aa5cdb4ab67 561 case SIMPLE_CARTESIAN:
Jonathan Austin 1:8aa5cdb4ab67 562 return -sample.y;
Jonathan Austin 1:8aa5cdb4ab67 563
Jonathan Austin 1:8aa5cdb4ab67 564 case NORTH_EAST_DOWN:
Jonathan Austin 1:8aa5cdb4ab67 565 return -sample.x;
Jonathan Austin 1:8aa5cdb4ab67 566
Jonathan Austin 1:8aa5cdb4ab67 567 case RAW:
Jonathan Austin 1:8aa5cdb4ab67 568 default:
Jonathan Austin 1:8aa5cdb4ab67 569 return sample.y;
Jonathan Austin 1:8aa5cdb4ab67 570 }
Jonathan Austin 1:8aa5cdb4ab67 571 }
Jonathan Austin 1:8aa5cdb4ab67 572
Jonathan Austin 1:8aa5cdb4ab67 573 /**
Jonathan Austin 1:8aa5cdb4ab67 574 * Reads the value of the Z axis from the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 575 *
Jonathan Austin 1:8aa5cdb4ab67 576 * @return The force measured in the Z axis, in milli-g.
Jonathan Austin 1:8aa5cdb4ab67 577 *
Jonathan Austin 1:8aa5cdb4ab67 578 * @code
Jonathan Austin 1:8aa5cdb4ab67 579 * accelerometer.getZ();
Jonathan Austin 1:8aa5cdb4ab67 580 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 581 */
Jonathan Austin 1:8aa5cdb4ab67 582 int MicroBitAccelerometer::getZ(MicroBitCoordinateSystem system)
Jonathan Austin 1:8aa5cdb4ab67 583 {
Jonathan Austin 1:8aa5cdb4ab67 584 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 585
Jonathan Austin 1:8aa5cdb4ab67 586 switch (system)
Jonathan Austin 1:8aa5cdb4ab67 587 {
Jonathan Austin 1:8aa5cdb4ab67 588 case NORTH_EAST_DOWN:
Jonathan Austin 1:8aa5cdb4ab67 589 return -sample.z;
Jonathan Austin 1:8aa5cdb4ab67 590
Jonathan Austin 1:8aa5cdb4ab67 591 case SIMPLE_CARTESIAN:
Jonathan Austin 1:8aa5cdb4ab67 592 case RAW:
Jonathan Austin 1:8aa5cdb4ab67 593 default:
Jonathan Austin 1:8aa5cdb4ab67 594 return sample.z;
Jonathan Austin 1:8aa5cdb4ab67 595 }
Jonathan Austin 1:8aa5cdb4ab67 596 }
Jonathan Austin 1:8aa5cdb4ab67 597
Jonathan Austin 1:8aa5cdb4ab67 598 /**
Jonathan Austin 1:8aa5cdb4ab67 599 * Provides a rotation compensated pitch of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 600 *
Jonathan Austin 1:8aa5cdb4ab67 601 * @return The pitch of the device, in degrees.
Jonathan Austin 1:8aa5cdb4ab67 602 *
Jonathan Austin 1:8aa5cdb4ab67 603 * @code
Jonathan Austin 1:8aa5cdb4ab67 604 * accelerometer.getPitch();
Jonathan Austin 1:8aa5cdb4ab67 605 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 606 */
Jonathan Austin 1:8aa5cdb4ab67 607 int MicroBitAccelerometer::getPitch()
Jonathan Austin 1:8aa5cdb4ab67 608 {
Jonathan Austin 1:8aa5cdb4ab67 609 return (int) ((360*getPitchRadians()) / (2*PI));
Jonathan Austin 1:8aa5cdb4ab67 610 }
Jonathan Austin 1:8aa5cdb4ab67 611
Jonathan Austin 1:8aa5cdb4ab67 612 /**
Jonathan Austin 1:8aa5cdb4ab67 613 * Provides a rotation compensated pitch of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 614 *
Jonathan Austin 1:8aa5cdb4ab67 615 * @return The pitch of the device, in radians.
Jonathan Austin 1:8aa5cdb4ab67 616 *
Jonathan Austin 1:8aa5cdb4ab67 617 * @code
Jonathan Austin 1:8aa5cdb4ab67 618 * accelerometer.getPitchRadians();
Jonathan Austin 1:8aa5cdb4ab67 619 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 620 */
Jonathan Austin 1:8aa5cdb4ab67 621 float MicroBitAccelerometer::getPitchRadians()
Jonathan Austin 1:8aa5cdb4ab67 622 {
Jonathan Austin 1:8aa5cdb4ab67 623 if (!(status & MICROBIT_ACCEL_PITCH_ROLL_VALID))
Jonathan Austin 1:8aa5cdb4ab67 624 recalculatePitchRoll();
Jonathan Austin 1:8aa5cdb4ab67 625
Jonathan Austin 1:8aa5cdb4ab67 626 return pitch;
Jonathan Austin 1:8aa5cdb4ab67 627 }
Jonathan Austin 1:8aa5cdb4ab67 628
Jonathan Austin 1:8aa5cdb4ab67 629 /**
Jonathan Austin 1:8aa5cdb4ab67 630 * Provides a rotation compensated roll of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 631 *
Jonathan Austin 1:8aa5cdb4ab67 632 * @return The roll of the device, in degrees.
Jonathan Austin 1:8aa5cdb4ab67 633 *
Jonathan Austin 1:8aa5cdb4ab67 634 * @code
Jonathan Austin 1:8aa5cdb4ab67 635 * accelerometer.getRoll();
Jonathan Austin 1:8aa5cdb4ab67 636 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 637 */
Jonathan Austin 1:8aa5cdb4ab67 638 int MicroBitAccelerometer::getRoll()
Jonathan Austin 1:8aa5cdb4ab67 639 {
Jonathan Austin 1:8aa5cdb4ab67 640 return (int) ((360*getRollRadians()) / (2*PI));
Jonathan Austin 1:8aa5cdb4ab67 641 }
Jonathan Austin 1:8aa5cdb4ab67 642
Jonathan Austin 1:8aa5cdb4ab67 643 /**
Jonathan Austin 1:8aa5cdb4ab67 644 * Provides a rotation compensated roll of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 645 *
Jonathan Austin 1:8aa5cdb4ab67 646 * @return The roll of the device, in radians.
Jonathan Austin 1:8aa5cdb4ab67 647 *
Jonathan Austin 1:8aa5cdb4ab67 648 * @code
Jonathan Austin 1:8aa5cdb4ab67 649 * accelerometer.getRollRadians();
Jonathan Austin 1:8aa5cdb4ab67 650 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 651 */
Jonathan Austin 1:8aa5cdb4ab67 652 float MicroBitAccelerometer::getRollRadians()
Jonathan Austin 1:8aa5cdb4ab67 653 {
Jonathan Austin 1:8aa5cdb4ab67 654 if (!(status & MICROBIT_ACCEL_PITCH_ROLL_VALID))
Jonathan Austin 1:8aa5cdb4ab67 655 recalculatePitchRoll();
Jonathan Austin 1:8aa5cdb4ab67 656
Jonathan Austin 1:8aa5cdb4ab67 657 return roll;
Jonathan Austin 1:8aa5cdb4ab67 658 }
Jonathan Austin 1:8aa5cdb4ab67 659
Jonathan Austin 1:8aa5cdb4ab67 660 /**
Jonathan Austin 1:8aa5cdb4ab67 661 * Recalculate roll and pitch values for the current sample.
Jonathan Austin 1:8aa5cdb4ab67 662 *
Jonathan Austin 1:8aa5cdb4ab67 663 * @note We only do this at most once per sample, as the necessary trigonemteric functions are rather
Jonathan Austin 1:8aa5cdb4ab67 664 * heavyweight for a CPU without a floating point unit.
Jonathan Austin 1:8aa5cdb4ab67 665 */
Jonathan Austin 1:8aa5cdb4ab67 666 void MicroBitAccelerometer::recalculatePitchRoll()
Jonathan Austin 1:8aa5cdb4ab67 667 {
Jonathan Austin 1:8aa5cdb4ab67 668 float x = (float) getX(NORTH_EAST_DOWN);
Jonathan Austin 1:8aa5cdb4ab67 669 float y = (float) getY(NORTH_EAST_DOWN);
Jonathan Austin 1:8aa5cdb4ab67 670 float z = (float) getZ(NORTH_EAST_DOWN);
Jonathan Austin 1:8aa5cdb4ab67 671
LancasterUniversity 6:2e1c2e0d8c7a 672 roll = atan2((double)getY(NORTH_EAST_DOWN), (double)getZ(NORTH_EAST_DOWN));
LancasterUniversity 6:2e1c2e0d8c7a 673
Jonathan Austin 1:8aa5cdb4ab67 674 pitch = atan(-x / (y*sin(roll) + z*cos(roll)));
Jonathan Austin 1:8aa5cdb4ab67 675 status |= MICROBIT_ACCEL_PITCH_ROLL_VALID;
Jonathan Austin 1:8aa5cdb4ab67 676 }
Jonathan Austin 1:8aa5cdb4ab67 677
Jonathan Austin 1:8aa5cdb4ab67 678 /**
Jonathan Austin 1:8aa5cdb4ab67 679 * Retrieves the last recorded gesture.
Jonathan Austin 1:8aa5cdb4ab67 680 *
Jonathan Austin 1:8aa5cdb4ab67 681 * @return The last gesture that was detected.
Jonathan Austin 1:8aa5cdb4ab67 682 *
Jonathan Austin 1:8aa5cdb4ab67 683 * Example:
Jonathan Austin 1:8aa5cdb4ab67 684 * @code
Jonathan Austin 1:8aa5cdb4ab67 685 * MicroBitDisplay display;
Jonathan Austin 1:8aa5cdb4ab67 686 *
Jonathan Austin 1:8aa5cdb4ab67 687 * if (accelerometer.getGesture() == SHAKE)
Jonathan Austin 1:8aa5cdb4ab67 688 * display.scroll("SHAKE!");
Jonathan Austin 1:8aa5cdb4ab67 689 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 690 */
Jonathan Austin 1:8aa5cdb4ab67 691 BasicGesture MicroBitAccelerometer::getGesture()
Jonathan Austin 1:8aa5cdb4ab67 692 {
Jonathan Austin 1:8aa5cdb4ab67 693 return lastGesture;
Jonathan Austin 1:8aa5cdb4ab67 694 }
Jonathan Austin 1:8aa5cdb4ab67 695
Jonathan Austin 1:8aa5cdb4ab67 696 /**
Jonathan Austin 1:8aa5cdb4ab67 697 * A periodic callback invoked by the fiber scheduler idle thread.
Jonathan Austin 1:8aa5cdb4ab67 698 *
Jonathan Austin 1:8aa5cdb4ab67 699 * Internally calls updateSample().
Jonathan Austin 1:8aa5cdb4ab67 700 */
Jonathan Austin 1:8aa5cdb4ab67 701 void MicroBitAccelerometer::idleTick()
Jonathan Austin 1:8aa5cdb4ab67 702 {
Jonathan Austin 1:8aa5cdb4ab67 703 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 704 }
Jonathan Austin 1:8aa5cdb4ab67 705
Jonathan Austin 1:8aa5cdb4ab67 706 /**
Jonathan Austin 1:8aa5cdb4ab67 707 * Returns 0 or 1. 1 indicates data is waiting to be read, zero means data is not ready to be read.
Jonathan Austin 1:8aa5cdb4ab67 708 *
Jonathan Austin 1:8aa5cdb4ab67 709 * We check if any data is ready for reading by checking the interrupt flag on the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 710 */
Jonathan Austin 1:8aa5cdb4ab67 711 int MicroBitAccelerometer::isIdleCallbackNeeded()
Jonathan Austin 1:8aa5cdb4ab67 712 {
Jonathan Austin 1:8aa5cdb4ab67 713 return !int1;
Jonathan Austin 1:8aa5cdb4ab67 714 }
Jonathan Austin 1:8aa5cdb4ab67 715
Jonathan Austin 1:8aa5cdb4ab67 716 /**
Jonathan Austin 1:8aa5cdb4ab67 717 * Destructor for MicroBitAccelerometer, where we deregister from the array of fiber components.
Jonathan Austin 1:8aa5cdb4ab67 718 */
Jonathan Austin 1:8aa5cdb4ab67 719 MicroBitAccelerometer::~MicroBitAccelerometer()
Jonathan Austin 1:8aa5cdb4ab67 720 {
Jonathan Austin 1:8aa5cdb4ab67 721 fiber_remove_idle_component(this);
Jonathan Austin 1:8aa5cdb4ab67 722 }
Jonathan Austin 1:8aa5cdb4ab67 723
Jonathan Austin 1:8aa5cdb4ab67 724 const MMA8653SampleRangeConfig MMA8653SampleRange[MMA8653_SAMPLE_RANGES] = {
Jonathan Austin 1:8aa5cdb4ab67 725 {2, 0},
Jonathan Austin 1:8aa5cdb4ab67 726 {4, 1},
Jonathan Austin 1:8aa5cdb4ab67 727 {8, 2}
Jonathan Austin 1:8aa5cdb4ab67 728 };
Jonathan Austin 1:8aa5cdb4ab67 729
Jonathan Austin 1:8aa5cdb4ab67 730 const MMA8653SampleRateConfig MMA8653SampleRate[MMA8653_SAMPLE_RATES] = {
Jonathan Austin 1:8aa5cdb4ab67 731 {1250, 0x00},
Jonathan Austin 1:8aa5cdb4ab67 732 {2500, 0x08},
Jonathan Austin 1:8aa5cdb4ab67 733 {5000, 0x10},
Jonathan Austin 1:8aa5cdb4ab67 734 {10000, 0x18},
Jonathan Austin 1:8aa5cdb4ab67 735 {20000, 0x20},
Jonathan Austin 1:8aa5cdb4ab67 736 {80000, 0x28},
Jonathan Austin 1:8aa5cdb4ab67 737 {160000, 0x30},
Jonathan Austin 1:8aa5cdb4ab67 738 {640000, 0x38}
LancasterUniversity 6:2e1c2e0d8c7a 739 };