Martin Woolley / microbit-dal-bluetooth-mdw_starter

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source/drivers/MicroBitAccelerometer.cpp@37:b624ae5e94a5, 2016-07-13 (annotated)

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:18:16 2016 +0100
Revision:
37:b624ae5e94a5
Parent:
6:2e1c2e0d8c7a
Child:
38:1a9e8e5e23f2
Synchronized with git rev 7443b783

Author: Joe Finney

Fix typos

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;
Jonathan Austin 1:8aa5cdb4ab67 192 this->lastGesture = GESTURE_NONE;
Jonathan Austin 1:8aa5cdb4ab67 193 this->currentGesture = GESTURE_NONE;
Jonathan Austin 1:8aa5cdb4ab67 194 this->shake.x = 0;
Jonathan Austin 1:8aa5cdb4ab67 195 this->shake.y = 0;
Jonathan Austin 1:8aa5cdb4ab67 196 this->shake.z = 0;
Jonathan Austin 1:8aa5cdb4ab67 197 this->shake.count = 0;
Jonathan Austin 1:8aa5cdb4ab67 198 this->shake.timer = 0;
Jonathan Austin 1:8aa5cdb4ab67 199
Jonathan Austin 1:8aa5cdb4ab67 200 // Configure and enable the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 201 if (this->configure() == MICROBIT_OK)
Jonathan Austin 1:8aa5cdb4ab67 202 status |= MICROBIT_COMPONENT_RUNNING;
Jonathan Austin 1:8aa5cdb4ab67 203 }
Jonathan Austin 1:8aa5cdb4ab67 204
Jonathan Austin 1:8aa5cdb4ab67 205 /**
Jonathan Austin 1:8aa5cdb4ab67 206 * Attempts to read the 8 bit ID from the accelerometer, this can be used for
Jonathan Austin 1:8aa5cdb4ab67 207 * validation purposes.
Jonathan Austin 1:8aa5cdb4ab67 208 *
Jonathan Austin 1:8aa5cdb4ab67 209 * @return the 8 bit ID returned by the accelerometer, or MICROBIT_I2C_ERROR if the request fails.
Jonathan Austin 1:8aa5cdb4ab67 210 *
Jonathan Austin 1:8aa5cdb4ab67 211 * @code
Jonathan Austin 1:8aa5cdb4ab67 212 * accelerometer.whoAmI();
Jonathan Austin 1:8aa5cdb4ab67 213 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 214 */
Jonathan Austin 1:8aa5cdb4ab67 215 int MicroBitAccelerometer::whoAmI()
Jonathan Austin 1:8aa5cdb4ab67 216 {
Jonathan Austin 1:8aa5cdb4ab67 217 uint8_t data;
Jonathan Austin 1:8aa5cdb4ab67 218 int result;
Jonathan Austin 1:8aa5cdb4ab67 219
Jonathan Austin 1:8aa5cdb4ab67 220 result = readCommand(MMA8653_WHOAMI, &data, 1);
Jonathan Austin 1:8aa5cdb4ab67 221 if (result !=0)
Jonathan Austin 1:8aa5cdb4ab67 222 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 223
Jonathan Austin 1:8aa5cdb4ab67 224 return (int)data;
Jonathan Austin 1:8aa5cdb4ab67 225 }
Jonathan Austin 1:8aa5cdb4ab67 226
Jonathan Austin 1:8aa5cdb4ab67 227 /**
Jonathan Austin 1:8aa5cdb4ab67 228 * Reads the acceleration data from the accelerometer, and stores it in our buffer.
Jonathan Austin 1:8aa5cdb4ab67 229 * This only happens if the accelerometer indicates that it has new data via int1.
Jonathan Austin 1:8aa5cdb4ab67 230 *
Jonathan Austin 1:8aa5cdb4ab67 231 * On first use, this member function will attempt to add this component to the
Jonathan Austin 1:8aa5cdb4ab67 232 * list of fiber components in order to constantly update the values stored
Jonathan Austin 1:8aa5cdb4ab67 233 * by this object.
Jonathan Austin 1:8aa5cdb4ab67 234 *
Jonathan Austin 1:8aa5cdb4ab67 235 * This technique is called lazy instantiation, and it means that we do not
Jonathan Austin 1:8aa5cdb4ab67 236 * obtain the overhead from non-chalantly adding this component to fiber components.
Jonathan Austin 1:8aa5cdb4ab67 237 *
Jonathan Austin 1:8aa5cdb4ab67 238 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if the read request fails.
Jonathan Austin 1:8aa5cdb4ab67 239 */
Jonathan Austin 1:8aa5cdb4ab67 240 int MicroBitAccelerometer::updateSample()
Jonathan Austin 1:8aa5cdb4ab67 241 {
Jonathan Austin 1:8aa5cdb4ab67 242 if(!(status & MICROBIT_ACCEL_ADDED_TO_IDLE))
Jonathan Austin 1:8aa5cdb4ab67 243 {
Jonathan Austin 1:8aa5cdb4ab67 244 fiber_add_idle_component(this);
Jonathan Austin 1:8aa5cdb4ab67 245 status |= MICROBIT_ACCEL_ADDED_TO_IDLE;
Jonathan Austin 1:8aa5cdb4ab67 246 }
Jonathan Austin 1:8aa5cdb4ab67 247
Jonathan Austin 1:8aa5cdb4ab67 248 // Poll interrupt line from accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 249 // n.b. Default is Active LO. Interrupt is cleared in data read.
Jonathan Austin 1:8aa5cdb4ab67 250 if(!int1)
Jonathan Austin 1:8aa5cdb4ab67 251 {
Jonathan Austin 1:8aa5cdb4ab67 252 int8_t data[6];
Jonathan Austin 1:8aa5cdb4ab67 253 int result;
Jonathan Austin 1:8aa5cdb4ab67 254
Jonathan Austin 1:8aa5cdb4ab67 255 result = readCommand(MMA8653_OUT_X_MSB, (uint8_t *)data, 6);
Jonathan Austin 1:8aa5cdb4ab67 256 if (result !=0)
Jonathan Austin 1:8aa5cdb4ab67 257 return MICROBIT_I2C_ERROR;
Jonathan Austin 1:8aa5cdb4ab67 258
Jonathan Austin 1:8aa5cdb4ab67 259 // read MSB values...
Jonathan Austin 1:8aa5cdb4ab67 260 sample.x = data[0];
Jonathan Austin 1:8aa5cdb4ab67 261 sample.y = data[2];
Jonathan Austin 1:8aa5cdb4ab67 262 sample.z = data[4];
Jonathan Austin 1:8aa5cdb4ab67 263
Jonathan Austin 1:8aa5cdb4ab67 264 // Normalize the data in the 0..1024 range.
Jonathan Austin 1:8aa5cdb4ab67 265 sample.x *= 8;
Jonathan Austin 1:8aa5cdb4ab67 266 sample.y *= 8;
Jonathan Austin 1:8aa5cdb4ab67 267 sample.z *= 8;
Jonathan Austin 1:8aa5cdb4ab67 268
Jonathan Austin 1:8aa5cdb4ab67 269 #if CONFIG_ENABLED(USE_ACCEL_LSB)
Jonathan Austin 1:8aa5cdb4ab67 270 // Add in LSB values.
Jonathan Austin 1:8aa5cdb4ab67 271 sample.x += (data[1] / 64);
Jonathan Austin 1:8aa5cdb4ab67 272 sample.y += (data[3] / 64);
Jonathan Austin 1:8aa5cdb4ab67 273 sample.z += (data[5] / 64);
Jonathan Austin 1:8aa5cdb4ab67 274 #endif
Jonathan Austin 1:8aa5cdb4ab67 275
Jonathan Austin 1:8aa5cdb4ab67 276 // Scale into millig (approx!)
Jonathan Austin 1:8aa5cdb4ab67 277 sample.x *= this->sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 278 sample.y *= this->sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 279 sample.z *= this->sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 280
Jonathan Austin 1:8aa5cdb4ab67 281 // Indicate that pitch and roll data is now stale, and needs to be recalculated if needed.
Jonathan Austin 1:8aa5cdb4ab67 282 status &= ~MICROBIT_ACCEL_PITCH_ROLL_VALID;
Jonathan Austin 1:8aa5cdb4ab67 283
Jonathan Austin 1:8aa5cdb4ab67 284 // Update gesture tracking
Jonathan Austin 1:8aa5cdb4ab67 285 updateGesture();
Jonathan Austin 1:8aa5cdb4ab67 286
Jonathan Austin 1:8aa5cdb4ab67 287 // Indicate that a new sample is available
Jonathan Austin 1:8aa5cdb4ab67 288 MicroBitEvent e(id, MICROBIT_ACCELEROMETER_EVT_DATA_UPDATE);
Jonathan Austin 1:8aa5cdb4ab67 289 }
Jonathan Austin 1:8aa5cdb4ab67 290
Jonathan Austin 1:8aa5cdb4ab67 291 return MICROBIT_OK;
Jonathan Austin 1:8aa5cdb4ab67 292 };
Jonathan Austin 1:8aa5cdb4ab67 293
Jonathan Austin 1:8aa5cdb4ab67 294 /**
Jonathan Austin 1:8aa5cdb4ab67 295 * A service function.
Jonathan Austin 1:8aa5cdb4ab67 296 * It calculates the current scalar acceleration of the device (x^2 + y^2 + z^2).
Jonathan Austin 1:8aa5cdb4ab67 297 * It does not, however, square root the result, as this is a relatively high cost operation.
Jonathan Austin 1:8aa5cdb4ab67 298 *
Jonathan Austin 1:8aa5cdb4ab67 299 * This is left to application code should it be needed.
Jonathan Austin 1:8aa5cdb4ab67 300 *
Jonathan Austin 1:8aa5cdb4ab67 301 * @return the sum of the square of the acceleration of the device across all axes.
Jonathan Austin 1:8aa5cdb4ab67 302 */
Jonathan Austin 1:8aa5cdb4ab67 303 int MicroBitAccelerometer::instantaneousAccelerationSquared()
Jonathan Austin 1:8aa5cdb4ab67 304 {
Jonathan Austin 1:8aa5cdb4ab67 305 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 306
Jonathan Austin 1:8aa5cdb4ab67 307 // Use pythagoras theorem to determine the combined force acting on the device.
Jonathan Austin 1:8aa5cdb4ab67 308 return (int)sample.x*(int)sample.x + (int)sample.y*(int)sample.y + (int)sample.z*(int)sample.z;
Jonathan Austin 1:8aa5cdb4ab67 309 }
Jonathan Austin 1:8aa5cdb4ab67 310
Jonathan Austin 1:8aa5cdb4ab67 311 /**
Jonathan Austin 1:8aa5cdb4ab67 312 * Service function.
Jonathan Austin 1:8aa5cdb4ab67 313 * Determines a 'best guess' posture of the device based on instantaneous data.
Jonathan Austin 1:8aa5cdb4ab67 314 *
LancasterUniversity 37:b624ae5e94a5 315 * This makes no use of historic data, and forms the input to the filter implemented in updateGesture().
Jonathan Austin 1:8aa5cdb4ab67 316 *
Jonathan Austin 1:8aa5cdb4ab67 317 * @return A 'best guess' of the current posture of the device, based on instanataneous data.
Jonathan Austin 1:8aa5cdb4ab67 318 */
Jonathan Austin 1:8aa5cdb4ab67 319 BasicGesture MicroBitAccelerometer::instantaneousPosture()
Jonathan Austin 1:8aa5cdb4ab67 320 {
Jonathan Austin 1:8aa5cdb4ab67 321 int force = instantaneousAccelerationSquared();
Jonathan Austin 1:8aa5cdb4ab67 322 bool shakeDetected = false;
Jonathan Austin 1:8aa5cdb4ab67 323
Jonathan Austin 1:8aa5cdb4ab67 324 // Test for shake events.
Jonathan Austin 1:8aa5cdb4ab67 325 // 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 326 // 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 327 //
Jonathan Austin 1:8aa5cdb4ab67 328 // If we see enough zero crossings in succession (MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD), then we decide that the device
Jonathan Austin 1:8aa5cdb4ab67 329 // has been shaken.
Jonathan Austin 1:8aa5cdb4ab67 330 if ((getX() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.x) || (getX() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.x))
Jonathan Austin 1:8aa5cdb4ab67 331 {
Jonathan Austin 1:8aa5cdb4ab67 332 shakeDetected = true;
Jonathan Austin 1:8aa5cdb4ab67 333 shake.x = !shake.x;
Jonathan Austin 1:8aa5cdb4ab67 334 }
Jonathan Austin 1:8aa5cdb4ab67 335
Jonathan Austin 1:8aa5cdb4ab67 336 if ((getY() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.y) || (getY() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.y))
Jonathan Austin 1:8aa5cdb4ab67 337 {
Jonathan Austin 1:8aa5cdb4ab67 338 shakeDetected = true;
Jonathan Austin 1:8aa5cdb4ab67 339 shake.y = !shake.y;
Jonathan Austin 1:8aa5cdb4ab67 340 }
Jonathan Austin 1:8aa5cdb4ab67 341
Jonathan Austin 1:8aa5cdb4ab67 342 if ((getZ() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.z) || (getZ() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.z))
Jonathan Austin 1:8aa5cdb4ab67 343 {
Jonathan Austin 1:8aa5cdb4ab67 344 shakeDetected = true;
Jonathan Austin 1:8aa5cdb4ab67 345 shake.z = !shake.z;
Jonathan Austin 1:8aa5cdb4ab67 346 }
Jonathan Austin 1:8aa5cdb4ab67 347
Jonathan Austin 1:8aa5cdb4ab67 348 if (shakeDetected && shake.count < MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD && ++shake.count == MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD)
Jonathan Austin 1:8aa5cdb4ab67 349 shake.shaken = 1;
Jonathan Austin 1:8aa5cdb4ab67 350
Jonathan Austin 1:8aa5cdb4ab67 351 if (++shake.timer >= MICROBIT_ACCELEROMETER_SHAKE_DAMPING)
Jonathan Austin 1:8aa5cdb4ab67 352 {
Jonathan Austin 1:8aa5cdb4ab67 353 shake.timer = 0;
Jonathan Austin 1:8aa5cdb4ab67 354 if (shake.count > 0)
Jonathan Austin 1:8aa5cdb4ab67 355 {
Jonathan Austin 1:8aa5cdb4ab67 356 if(--shake.count == 0)
Jonathan Austin 1:8aa5cdb4ab67 357 shake.shaken = 0;
Jonathan Austin 1:8aa5cdb4ab67 358 }
Jonathan Austin 1:8aa5cdb4ab67 359 }
Jonathan Austin 1:8aa5cdb4ab67 360
Jonathan Austin 1:8aa5cdb4ab67 361 if (shake.shaken)
Jonathan Austin 1:8aa5cdb4ab67 362 return GESTURE_SHAKE;
Jonathan Austin 1:8aa5cdb4ab67 363
Jonathan Austin 1:8aa5cdb4ab67 364 if (force < MICROBIT_ACCELEROMETER_FREEFALL_THRESHOLD)
Jonathan Austin 1:8aa5cdb4ab67 365 return GESTURE_FREEFALL;
Jonathan Austin 1:8aa5cdb4ab67 366
Jonathan Austin 1:8aa5cdb4ab67 367 if (force > MICROBIT_ACCELEROMETER_3G_THRESHOLD)
Jonathan Austin 1:8aa5cdb4ab67 368 return GESTURE_3G;
Jonathan Austin 1:8aa5cdb4ab67 369
Jonathan Austin 1:8aa5cdb4ab67 370 if (force > MICROBIT_ACCELEROMETER_6G_THRESHOLD)
Jonathan Austin 1:8aa5cdb4ab67 371 return GESTURE_6G;
Jonathan Austin 1:8aa5cdb4ab67 372
Jonathan Austin 1:8aa5cdb4ab67 373 if (force > MICROBIT_ACCELEROMETER_8G_THRESHOLD)
Jonathan Austin 1:8aa5cdb4ab67 374 return GESTURE_8G;
Jonathan Austin 1:8aa5cdb4ab67 375
Jonathan Austin 1:8aa5cdb4ab67 376 // Determine our posture.
Jonathan Austin 1:8aa5cdb4ab67 377 if (getX() < (-1000 + MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 378 return GESTURE_LEFT;
Jonathan Austin 1:8aa5cdb4ab67 379
Jonathan Austin 1:8aa5cdb4ab67 380 if (getX() > (1000 - MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 381 return GESTURE_RIGHT;
Jonathan Austin 1:8aa5cdb4ab67 382
Jonathan Austin 1:8aa5cdb4ab67 383 if (getY() < (-1000 + MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 384 return GESTURE_DOWN;
Jonathan Austin 1:8aa5cdb4ab67 385
Jonathan Austin 1:8aa5cdb4ab67 386 if (getY() > (1000 - MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 387 return GESTURE_UP;
Jonathan Austin 1:8aa5cdb4ab67 388
Jonathan Austin 1:8aa5cdb4ab67 389 if (getZ() < (-1000 + MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 390 return GESTURE_FACE_UP;
Jonathan Austin 1:8aa5cdb4ab67 391
Jonathan Austin 1:8aa5cdb4ab67 392 if (getZ() > (1000 - MICROBIT_ACCELEROMETER_TILT_TOLERANCE))
Jonathan Austin 1:8aa5cdb4ab67 393 return GESTURE_FACE_DOWN;
Jonathan Austin 1:8aa5cdb4ab67 394
Jonathan Austin 1:8aa5cdb4ab67 395 return GESTURE_NONE;
Jonathan Austin 1:8aa5cdb4ab67 396 }
Jonathan Austin 1:8aa5cdb4ab67 397
Jonathan Austin 1:8aa5cdb4ab67 398 /**
Jonathan Austin 1:8aa5cdb4ab67 399 * Updates the basic gesture recognizer. This performs instantaneous pose recognition, and also some low pass filtering to promote
Jonathan Austin 1:8aa5cdb4ab67 400 * stability.
Jonathan Austin 1:8aa5cdb4ab67 401 */
Jonathan Austin 1:8aa5cdb4ab67 402 void MicroBitAccelerometer::updateGesture()
Jonathan Austin 1:8aa5cdb4ab67 403 {
Jonathan Austin 1:8aa5cdb4ab67 404 // Determine what it looks like we're doing based on the latest sample...
Jonathan Austin 1:8aa5cdb4ab67 405 BasicGesture g = instantaneousPosture();
Jonathan Austin 1:8aa5cdb4ab67 406
Jonathan Austin 1:8aa5cdb4ab67 407 // Perform some low pass filtering to reduce jitter from any detected effects
Jonathan Austin 1:8aa5cdb4ab67 408 if (g == currentGesture)
Jonathan Austin 1:8aa5cdb4ab67 409 {
Jonathan Austin 1:8aa5cdb4ab67 410 if (sigma < MICROBIT_ACCELEROMETER_GESTURE_DAMPING)
Jonathan Austin 1:8aa5cdb4ab67 411 sigma++;
Jonathan Austin 1:8aa5cdb4ab67 412 }
Jonathan Austin 1:8aa5cdb4ab67 413 else
Jonathan Austin 1:8aa5cdb4ab67 414 {
Jonathan Austin 1:8aa5cdb4ab67 415 currentGesture = g;
Jonathan Austin 1:8aa5cdb4ab67 416 sigma = 0;
Jonathan Austin 1:8aa5cdb4ab67 417 }
Jonathan Austin 1:8aa5cdb4ab67 418
Jonathan Austin 1:8aa5cdb4ab67 419 // If we've reached threshold, update our record and raise the relevant event...
Jonathan Austin 1:8aa5cdb4ab67 420 if (currentGesture != lastGesture && sigma >= MICROBIT_ACCELEROMETER_GESTURE_DAMPING)
Jonathan Austin 1:8aa5cdb4ab67 421 {
Jonathan Austin 1:8aa5cdb4ab67 422 lastGesture = currentGesture;
Jonathan Austin 1:8aa5cdb4ab67 423 MicroBitEvent e(MICROBIT_ID_GESTURE, lastGesture);
Jonathan Austin 1:8aa5cdb4ab67 424 }
Jonathan Austin 1:8aa5cdb4ab67 425 }
Jonathan Austin 1:8aa5cdb4ab67 426
Jonathan Austin 1:8aa5cdb4ab67 427 /**
Jonathan Austin 1:8aa5cdb4ab67 428 * Attempts to set the sample rate of the accelerometer to the specified value (in ms).
Jonathan Austin 1:8aa5cdb4ab67 429 *
Jonathan Austin 1:8aa5cdb4ab67 430 * @param period the requested time between samples, in milliseconds.
Jonathan Austin 1:8aa5cdb4ab67 431 *
Jonathan Austin 1:8aa5cdb4ab67 432 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR is the request fails.
Jonathan Austin 1:8aa5cdb4ab67 433 *
Jonathan Austin 1:8aa5cdb4ab67 434 * @code
Jonathan Austin 1:8aa5cdb4ab67 435 * // sample rate is now 20 ms.
Jonathan Austin 1:8aa5cdb4ab67 436 * accelerometer.setPeriod(20);
Jonathan Austin 1:8aa5cdb4ab67 437 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 438 *
Jonathan Austin 1:8aa5cdb4ab67 439 * @note The requested rate may not be possible on the hardware. In this case, the
Jonathan Austin 1:8aa5cdb4ab67 440 * nearest lower rate is chosen.
Jonathan Austin 1:8aa5cdb4ab67 441 */
Jonathan Austin 1:8aa5cdb4ab67 442 int MicroBitAccelerometer::setPeriod(int period)
Jonathan Austin 1:8aa5cdb4ab67 443 {
Jonathan Austin 1:8aa5cdb4ab67 444 this->samplePeriod = period;
Jonathan Austin 1:8aa5cdb4ab67 445 return this->configure();
Jonathan Austin 1:8aa5cdb4ab67 446 }
Jonathan Austin 1:8aa5cdb4ab67 447
Jonathan Austin 1:8aa5cdb4ab67 448 /**
Jonathan Austin 1:8aa5cdb4ab67 449 * Reads the currently configured sample rate of the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 450 *
Jonathan Austin 1:8aa5cdb4ab67 451 * @return The time between samples, in milliseconds.
Jonathan Austin 1:8aa5cdb4ab67 452 */
Jonathan Austin 1:8aa5cdb4ab67 453 int MicroBitAccelerometer::getPeriod()
Jonathan Austin 1:8aa5cdb4ab67 454 {
Jonathan Austin 1:8aa5cdb4ab67 455 return (int)samplePeriod;
Jonathan Austin 1:8aa5cdb4ab67 456 }
Jonathan Austin 1:8aa5cdb4ab67 457
Jonathan Austin 1:8aa5cdb4ab67 458 /**
Jonathan Austin 1:8aa5cdb4ab67 459 * Attempts to set the sample range of the accelerometer to the specified value (in g).
Jonathan Austin 1:8aa5cdb4ab67 460 *
Jonathan Austin 1:8aa5cdb4ab67 461 * @param range The requested sample range of samples, in g.
Jonathan Austin 1:8aa5cdb4ab67 462 *
Jonathan Austin 1:8aa5cdb4ab67 463 * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR is the request fails.
Jonathan Austin 1:8aa5cdb4ab67 464 *
Jonathan Austin 1:8aa5cdb4ab67 465 * @code
Jonathan Austin 1:8aa5cdb4ab67 466 * // the sample range of the accelerometer is now 8G.
Jonathan Austin 1:8aa5cdb4ab67 467 * accelerometer.setRange(8);
Jonathan Austin 1:8aa5cdb4ab67 468 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 469 *
Jonathan Austin 1:8aa5cdb4ab67 470 * @note The requested range may not be possible on the hardware. In this case, the
Jonathan Austin 1:8aa5cdb4ab67 471 * nearest lower range is chosen.
Jonathan Austin 1:8aa5cdb4ab67 472 */
Jonathan Austin 1:8aa5cdb4ab67 473 int MicroBitAccelerometer::setRange(int range)
Jonathan Austin 1:8aa5cdb4ab67 474 {
Jonathan Austin 1:8aa5cdb4ab67 475 this->sampleRange = range;
Jonathan Austin 1:8aa5cdb4ab67 476 return this->configure();
Jonathan Austin 1:8aa5cdb4ab67 477 }
Jonathan Austin 1:8aa5cdb4ab67 478
Jonathan Austin 1:8aa5cdb4ab67 479 /**
Jonathan Austin 1:8aa5cdb4ab67 480 * Reads the currently configured sample range of the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 481 *
Jonathan Austin 1:8aa5cdb4ab67 482 * @return The sample range, in g.
Jonathan Austin 1:8aa5cdb4ab67 483 */
Jonathan Austin 1:8aa5cdb4ab67 484 int MicroBitAccelerometer::getRange()
Jonathan Austin 1:8aa5cdb4ab67 485 {
Jonathan Austin 1:8aa5cdb4ab67 486 return (int)sampleRange;
Jonathan Austin 1:8aa5cdb4ab67 487 }
Jonathan Austin 1:8aa5cdb4ab67 488
Jonathan Austin 1:8aa5cdb4ab67 489 /**
Jonathan Austin 1:8aa5cdb4ab67 490 * Reads the value of the X axis from the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 491 *
Jonathan Austin 1:8aa5cdb4ab67 492 * @param system The coordinate system to use. By default, a simple cartesian system is provided.
Jonathan Austin 1:8aa5cdb4ab67 493 *
Jonathan Austin 1:8aa5cdb4ab67 494 * @return The force measured in the X axis, in milli-g.
Jonathan Austin 1:8aa5cdb4ab67 495 *
Jonathan Austin 1:8aa5cdb4ab67 496 * @code
Jonathan Austin 1:8aa5cdb4ab67 497 * accelerometer.getX();
Jonathan Austin 1:8aa5cdb4ab67 498 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 499 */
Jonathan Austin 1:8aa5cdb4ab67 500 int MicroBitAccelerometer::getX(MicroBitCoordinateSystem system)
Jonathan Austin 1:8aa5cdb4ab67 501 {
Jonathan Austin 1:8aa5cdb4ab67 502 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 503
Jonathan Austin 1:8aa5cdb4ab67 504 switch (system)
Jonathan Austin 1:8aa5cdb4ab67 505 {
Jonathan Austin 1:8aa5cdb4ab67 506 case SIMPLE_CARTESIAN:
Jonathan Austin 1:8aa5cdb4ab67 507 return -sample.x;
Jonathan Austin 1:8aa5cdb4ab67 508
Jonathan Austin 1:8aa5cdb4ab67 509 case NORTH_EAST_DOWN:
Jonathan Austin 1:8aa5cdb4ab67 510 return sample.y;
Jonathan Austin 1:8aa5cdb4ab67 511
Jonathan Austin 1:8aa5cdb4ab67 512 case RAW:
Jonathan Austin 1:8aa5cdb4ab67 513 default:
Jonathan Austin 1:8aa5cdb4ab67 514 return sample.x;
Jonathan Austin 1:8aa5cdb4ab67 515 }
Jonathan Austin 1:8aa5cdb4ab67 516 }
Jonathan Austin 1:8aa5cdb4ab67 517
Jonathan Austin 1:8aa5cdb4ab67 518 /**
Jonathan Austin 1:8aa5cdb4ab67 519 * Reads the value of the Y axis from the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 520 *
Jonathan Austin 1:8aa5cdb4ab67 521 * @return The force measured in the Y axis, in milli-g.
Jonathan Austin 1:8aa5cdb4ab67 522 *
Jonathan Austin 1:8aa5cdb4ab67 523 * @code
Jonathan Austin 1:8aa5cdb4ab67 524 * accelerometer.getY();
Jonathan Austin 1:8aa5cdb4ab67 525 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 526 */
Jonathan Austin 1:8aa5cdb4ab67 527 int MicroBitAccelerometer::getY(MicroBitCoordinateSystem system)
Jonathan Austin 1:8aa5cdb4ab67 528 {
Jonathan Austin 1:8aa5cdb4ab67 529 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 530
Jonathan Austin 1:8aa5cdb4ab67 531 switch (system)
Jonathan Austin 1:8aa5cdb4ab67 532 {
Jonathan Austin 1:8aa5cdb4ab67 533 case SIMPLE_CARTESIAN:
Jonathan Austin 1:8aa5cdb4ab67 534 return -sample.y;
Jonathan Austin 1:8aa5cdb4ab67 535
Jonathan Austin 1:8aa5cdb4ab67 536 case NORTH_EAST_DOWN:
Jonathan Austin 1:8aa5cdb4ab67 537 return -sample.x;
Jonathan Austin 1:8aa5cdb4ab67 538
Jonathan Austin 1:8aa5cdb4ab67 539 case RAW:
Jonathan Austin 1:8aa5cdb4ab67 540 default:
Jonathan Austin 1:8aa5cdb4ab67 541 return sample.y;
Jonathan Austin 1:8aa5cdb4ab67 542 }
Jonathan Austin 1:8aa5cdb4ab67 543 }
Jonathan Austin 1:8aa5cdb4ab67 544
Jonathan Austin 1:8aa5cdb4ab67 545 /**
Jonathan Austin 1:8aa5cdb4ab67 546 * Reads the value of the Z axis from the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 547 *
Jonathan Austin 1:8aa5cdb4ab67 548 * @return The force measured in the Z axis, in milli-g.
Jonathan Austin 1:8aa5cdb4ab67 549 *
Jonathan Austin 1:8aa5cdb4ab67 550 * @code
Jonathan Austin 1:8aa5cdb4ab67 551 * accelerometer.getZ();
Jonathan Austin 1:8aa5cdb4ab67 552 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 553 */
Jonathan Austin 1:8aa5cdb4ab67 554 int MicroBitAccelerometer::getZ(MicroBitCoordinateSystem system)
Jonathan Austin 1:8aa5cdb4ab67 555 {
Jonathan Austin 1:8aa5cdb4ab67 556 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 557
Jonathan Austin 1:8aa5cdb4ab67 558 switch (system)
Jonathan Austin 1:8aa5cdb4ab67 559 {
Jonathan Austin 1:8aa5cdb4ab67 560 case NORTH_EAST_DOWN:
Jonathan Austin 1:8aa5cdb4ab67 561 return -sample.z;
Jonathan Austin 1:8aa5cdb4ab67 562
Jonathan Austin 1:8aa5cdb4ab67 563 case SIMPLE_CARTESIAN:
Jonathan Austin 1:8aa5cdb4ab67 564 case RAW:
Jonathan Austin 1:8aa5cdb4ab67 565 default:
Jonathan Austin 1:8aa5cdb4ab67 566 return sample.z;
Jonathan Austin 1:8aa5cdb4ab67 567 }
Jonathan Austin 1:8aa5cdb4ab67 568 }
Jonathan Austin 1:8aa5cdb4ab67 569
Jonathan Austin 1:8aa5cdb4ab67 570 /**
Jonathan Austin 1:8aa5cdb4ab67 571 * Provides a rotation compensated pitch of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 572 *
Jonathan Austin 1:8aa5cdb4ab67 573 * @return The pitch of the device, in degrees.
Jonathan Austin 1:8aa5cdb4ab67 574 *
Jonathan Austin 1:8aa5cdb4ab67 575 * @code
Jonathan Austin 1:8aa5cdb4ab67 576 * accelerometer.getPitch();
Jonathan Austin 1:8aa5cdb4ab67 577 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 578 */
Jonathan Austin 1:8aa5cdb4ab67 579 int MicroBitAccelerometer::getPitch()
Jonathan Austin 1:8aa5cdb4ab67 580 {
Jonathan Austin 1:8aa5cdb4ab67 581 return (int) ((360*getPitchRadians()) / (2*PI));
Jonathan Austin 1:8aa5cdb4ab67 582 }
Jonathan Austin 1:8aa5cdb4ab67 583
Jonathan Austin 1:8aa5cdb4ab67 584 /**
Jonathan Austin 1:8aa5cdb4ab67 585 * Provides a rotation compensated pitch of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 586 *
Jonathan Austin 1:8aa5cdb4ab67 587 * @return The pitch of the device, in radians.
Jonathan Austin 1:8aa5cdb4ab67 588 *
Jonathan Austin 1:8aa5cdb4ab67 589 * @code
Jonathan Austin 1:8aa5cdb4ab67 590 * accelerometer.getPitchRadians();
Jonathan Austin 1:8aa5cdb4ab67 591 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 592 */
Jonathan Austin 1:8aa5cdb4ab67 593 float MicroBitAccelerometer::getPitchRadians()
Jonathan Austin 1:8aa5cdb4ab67 594 {
Jonathan Austin 1:8aa5cdb4ab67 595 if (!(status & MICROBIT_ACCEL_PITCH_ROLL_VALID))
Jonathan Austin 1:8aa5cdb4ab67 596 recalculatePitchRoll();
Jonathan Austin 1:8aa5cdb4ab67 597
Jonathan Austin 1:8aa5cdb4ab67 598 return pitch;
Jonathan Austin 1:8aa5cdb4ab67 599 }
Jonathan Austin 1:8aa5cdb4ab67 600
Jonathan Austin 1:8aa5cdb4ab67 601 /**
Jonathan Austin 1:8aa5cdb4ab67 602 * Provides a rotation compensated roll of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 603 *
Jonathan Austin 1:8aa5cdb4ab67 604 * @return The roll of the device, in degrees.
Jonathan Austin 1:8aa5cdb4ab67 605 *
Jonathan Austin 1:8aa5cdb4ab67 606 * @code
Jonathan Austin 1:8aa5cdb4ab67 607 * accelerometer.getRoll();
Jonathan Austin 1:8aa5cdb4ab67 608 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 609 */
Jonathan Austin 1:8aa5cdb4ab67 610 int MicroBitAccelerometer::getRoll()
Jonathan Austin 1:8aa5cdb4ab67 611 {
Jonathan Austin 1:8aa5cdb4ab67 612 return (int) ((360*getRollRadians()) / (2*PI));
Jonathan Austin 1:8aa5cdb4ab67 613 }
Jonathan Austin 1:8aa5cdb4ab67 614
Jonathan Austin 1:8aa5cdb4ab67 615 /**
Jonathan Austin 1:8aa5cdb4ab67 616 * Provides a rotation compensated roll of the device, based on the latest update retrieved from the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 617 *
Jonathan Austin 1:8aa5cdb4ab67 618 * @return The roll of the device, in radians.
Jonathan Austin 1:8aa5cdb4ab67 619 *
Jonathan Austin 1:8aa5cdb4ab67 620 * @code
Jonathan Austin 1:8aa5cdb4ab67 621 * accelerometer.getRollRadians();
Jonathan Austin 1:8aa5cdb4ab67 622 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 623 */
Jonathan Austin 1:8aa5cdb4ab67 624 float MicroBitAccelerometer::getRollRadians()
Jonathan Austin 1:8aa5cdb4ab67 625 {
Jonathan Austin 1:8aa5cdb4ab67 626 if (!(status & MICROBIT_ACCEL_PITCH_ROLL_VALID))
Jonathan Austin 1:8aa5cdb4ab67 627 recalculatePitchRoll();
Jonathan Austin 1:8aa5cdb4ab67 628
Jonathan Austin 1:8aa5cdb4ab67 629 return roll;
Jonathan Austin 1:8aa5cdb4ab67 630 }
Jonathan Austin 1:8aa5cdb4ab67 631
Jonathan Austin 1:8aa5cdb4ab67 632 /**
Jonathan Austin 1:8aa5cdb4ab67 633 * Recalculate roll and pitch values for the current sample.
Jonathan Austin 1:8aa5cdb4ab67 634 *
Jonathan Austin 1:8aa5cdb4ab67 635 * @note We only do this at most once per sample, as the necessary trigonemteric functions are rather
Jonathan Austin 1:8aa5cdb4ab67 636 * heavyweight for a CPU without a floating point unit.
Jonathan Austin 1:8aa5cdb4ab67 637 */
Jonathan Austin 1:8aa5cdb4ab67 638 void MicroBitAccelerometer::recalculatePitchRoll()
Jonathan Austin 1:8aa5cdb4ab67 639 {
Jonathan Austin 1:8aa5cdb4ab67 640 float x = (float) getX(NORTH_EAST_DOWN);
Jonathan Austin 1:8aa5cdb4ab67 641 float y = (float) getY(NORTH_EAST_DOWN);
Jonathan Austin 1:8aa5cdb4ab67 642 float z = (float) getZ(NORTH_EAST_DOWN);
Jonathan Austin 1:8aa5cdb4ab67 643
LancasterUniversity 6:2e1c2e0d8c7a 644 roll = atan2((double)getY(NORTH_EAST_DOWN), (double)getZ(NORTH_EAST_DOWN));
LancasterUniversity 6:2e1c2e0d8c7a 645
Jonathan Austin 1:8aa5cdb4ab67 646 pitch = atan(-x / (y*sin(roll) + z*cos(roll)));
Jonathan Austin 1:8aa5cdb4ab67 647 status |= MICROBIT_ACCEL_PITCH_ROLL_VALID;
Jonathan Austin 1:8aa5cdb4ab67 648 }
Jonathan Austin 1:8aa5cdb4ab67 649
Jonathan Austin 1:8aa5cdb4ab67 650 /**
Jonathan Austin 1:8aa5cdb4ab67 651 * Retrieves the last recorded gesture.
Jonathan Austin 1:8aa5cdb4ab67 652 *
Jonathan Austin 1:8aa5cdb4ab67 653 * @return The last gesture that was detected.
Jonathan Austin 1:8aa5cdb4ab67 654 *
Jonathan Austin 1:8aa5cdb4ab67 655 * Example:
Jonathan Austin 1:8aa5cdb4ab67 656 * @code
Jonathan Austin 1:8aa5cdb4ab67 657 * MicroBitDisplay display;
Jonathan Austin 1:8aa5cdb4ab67 658 *
Jonathan Austin 1:8aa5cdb4ab67 659 * if (accelerometer.getGesture() == SHAKE)
Jonathan Austin 1:8aa5cdb4ab67 660 * display.scroll("SHAKE!");
Jonathan Austin 1:8aa5cdb4ab67 661 * @endcode
Jonathan Austin 1:8aa5cdb4ab67 662 */
Jonathan Austin 1:8aa5cdb4ab67 663 BasicGesture MicroBitAccelerometer::getGesture()
Jonathan Austin 1:8aa5cdb4ab67 664 {
Jonathan Austin 1:8aa5cdb4ab67 665 return lastGesture;
Jonathan Austin 1:8aa5cdb4ab67 666 }
Jonathan Austin 1:8aa5cdb4ab67 667
Jonathan Austin 1:8aa5cdb4ab67 668 /**
Jonathan Austin 1:8aa5cdb4ab67 669 * A periodic callback invoked by the fiber scheduler idle thread.
Jonathan Austin 1:8aa5cdb4ab67 670 *
Jonathan Austin 1:8aa5cdb4ab67 671 * Internally calls updateSample().
Jonathan Austin 1:8aa5cdb4ab67 672 */
Jonathan Austin 1:8aa5cdb4ab67 673 void MicroBitAccelerometer::idleTick()
Jonathan Austin 1:8aa5cdb4ab67 674 {
Jonathan Austin 1:8aa5cdb4ab67 675 updateSample();
Jonathan Austin 1:8aa5cdb4ab67 676 }
Jonathan Austin 1:8aa5cdb4ab67 677
Jonathan Austin 1:8aa5cdb4ab67 678 /**
Jonathan Austin 1:8aa5cdb4ab67 679 * 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 680 *
Jonathan Austin 1:8aa5cdb4ab67 681 * We check if any data is ready for reading by checking the interrupt flag on the accelerometer.
Jonathan Austin 1:8aa5cdb4ab67 682 */
Jonathan Austin 1:8aa5cdb4ab67 683 int MicroBitAccelerometer::isIdleCallbackNeeded()
Jonathan Austin 1:8aa5cdb4ab67 684 {
Jonathan Austin 1:8aa5cdb4ab67 685 return !int1;
Jonathan Austin 1:8aa5cdb4ab67 686 }
Jonathan Austin 1:8aa5cdb4ab67 687
Jonathan Austin 1:8aa5cdb4ab67 688 /**
Jonathan Austin 1:8aa5cdb4ab67 689 * Destructor for MicroBitAccelerometer, where we deregister from the array of fiber components.
Jonathan Austin 1:8aa5cdb4ab67 690 */
Jonathan Austin 1:8aa5cdb4ab67 691 MicroBitAccelerometer::~MicroBitAccelerometer()
Jonathan Austin 1:8aa5cdb4ab67 692 {
Jonathan Austin 1:8aa5cdb4ab67 693 fiber_remove_idle_component(this);
Jonathan Austin 1:8aa5cdb4ab67 694 }
Jonathan Austin 1:8aa5cdb4ab67 695
Jonathan Austin 1:8aa5cdb4ab67 696 const MMA8653SampleRangeConfig MMA8653SampleRange[MMA8653_SAMPLE_RANGES] = {
Jonathan Austin 1:8aa5cdb4ab67 697 {2, 0},
Jonathan Austin 1:8aa5cdb4ab67 698 {4, 1},
Jonathan Austin 1:8aa5cdb4ab67 699 {8, 2}
Jonathan Austin 1:8aa5cdb4ab67 700 };
Jonathan Austin 1:8aa5cdb4ab67 701
Jonathan Austin 1:8aa5cdb4ab67 702 const MMA8653SampleRateConfig MMA8653SampleRate[MMA8653_SAMPLE_RATES] = {
Jonathan Austin 1:8aa5cdb4ab67 703 {1250, 0x00},
Jonathan Austin 1:8aa5cdb4ab67 704 {2500, 0x08},
Jonathan Austin 1:8aa5cdb4ab67 705 {5000, 0x10},
Jonathan Austin 1:8aa5cdb4ab67 706 {10000, 0x18},
Jonathan Austin 1:8aa5cdb4ab67 707 {20000, 0x20},
Jonathan Austin 1:8aa5cdb4ab67 708 {80000, 0x28},
Jonathan Austin 1:8aa5cdb4ab67 709 {160000, 0x30},
Jonathan Austin 1:8aa5cdb4ab67 710 {640000, 0x38}
LancasterUniversity 6:2e1c2e0d8c7a 711 };