Kamil Foryszewski / MPU6050

MPU6050 library using i2c interface on LPC1768 - Complementary filter is added. Now program can calculate pitch and roll angles.

Fork of MPU6050 by Baser Kandehir

MPU6050.cpp@5:5bff0edcdff8, 2015-08-05 (annotated)

Committer:
BaserK
Date:
Wed Aug 05 12:45:47 2015 +0000
Revision:
5:5bff0edcdff8
Parent:
4:20f1f660e5c3
Child:
6:5b90f2b5e6d9
i2c object is no more extern

Who changed what in which revision?

UserRevisionLine numberNew contents of line
BaserK 4:20f1f660e5c3 1 /* MPU6050 Library
BaserK 4:20f1f660e5c3 2 *
BaserK 4:20f1f660e5c3 3 * @author: Baser Kandehir
BaserK 2:3e0dfce73a58 4 * @date: July 16, 2015
BaserK 3:a173ad187e67 5 * @license: MIT license
BaserK 3:a173ad187e67 6 *
BaserK 3:a173ad187e67 7 * Copyright (c) 2015, Baser Kandehir, baser.kandehir@ieee.metu.edu.tr
BaserK 3:a173ad187e67 8 *
BaserK 3:a173ad187e67 9 * Permission is hereby granted, free of charge, to any person obtaining a copy
BaserK 3:a173ad187e67 10 * of this software and associated documentation files (the "Software"), to deal
BaserK 3:a173ad187e67 11 * in the Software without restriction, including without limitation the rights
BaserK 3:a173ad187e67 12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
BaserK 3:a173ad187e67 13 * copies of the Software, and to permit persons to whom the Software is
BaserK 3:a173ad187e67 14 * furnished to do so, subject to the following conditions:
BaserK 3:a173ad187e67 15 *
BaserK 3:a173ad187e67 16 * The above copyright notice and this permission notice shall be included in
BaserK 3:a173ad187e67 17 * all copies or substantial portions of the Software.
BaserK 3:a173ad187e67 18 *
BaserK 3:a173ad187e67 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
BaserK 3:a173ad187e67 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
BaserK 3:a173ad187e67 21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
BaserK 3:a173ad187e67 22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
BaserK 3:a173ad187e67 23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
BaserK 3:a173ad187e67 24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
BaserK 3:a173ad187e67 25 * THE SOFTWARE.
BaserK 3:a173ad187e67 26 *
BaserK 0:954f15bd95f1 27 */
BaserK 0:954f15bd95f1 28
BaserK 0:954f15bd95f1 29 // Most of the code is adapted from Kris Winer's MPU6050 library
BaserK 0:954f15bd95f1 30
BaserK 0:954f15bd95f1 31 #include "MPU6050.h"
BaserK 0:954f15bd95f1 32
BaserK 4:20f1f660e5c3 33 /* For LPC1768 board */
BaserK 4:20f1f660e5c3 34 //I2C i2c(p9,p10); // setup i2c (SDA,SCL)
BaserK 4:20f1f660e5c3 35
BaserK 4:20f1f660e5c3 36 /* For NUCLEO-F411RE board */
BaserK 4:20f1f660e5c3 37 I2C i2c(D14,D15); // setup i2c (SDA,SCL)
BaserK 0:954f15bd95f1 38
BaserK 0:954f15bd95f1 39 /* Set initial input parameters */
BaserK 0:954f15bd95f1 40
BaserK 0:954f15bd95f1 41 // Acc Full Scale Range +-2G 4G 8G 16G
BaserK 0:954f15bd95f1 42 enum Ascale
BaserK 0:954f15bd95f1 43 {
BaserK 0:954f15bd95f1 44 AFS_2G=0,
BaserK 0:954f15bd95f1 45 AFS_4G,
BaserK 0:954f15bd95f1 46 AFS_8G,
BaserK 0:954f15bd95f1 47 AFS_16G
BaserK 0:954f15bd95f1 48 };
BaserK 0:954f15bd95f1 49
BaserK 0:954f15bd95f1 50 // Gyro Full Scale Range +-250 500 1000 2000 Degrees per second
BaserK 0:954f15bd95f1 51 enum Gscale
BaserK 0:954f15bd95f1 52 {
BaserK 0:954f15bd95f1 53 GFS_250DPS=0,
BaserK 0:954f15bd95f1 54 GFS_500DPS,
BaserK 0:954f15bd95f1 55 GFS_1000DPS,
BaserK 0:954f15bd95f1 56 GFS_2000DPS
BaserK 0:954f15bd95f1 57 };
BaserK 0:954f15bd95f1 58
BaserK 0:954f15bd95f1 59 // Sensor datas
BaserK 0:954f15bd95f1 60 float ax,ay,az;
BaserK 0:954f15bd95f1 61 float gx,gy,gz;
BaserK 0:954f15bd95f1 62 int16_t accelData[3],gyroData[3],tempData;
BaserK 0:954f15bd95f1 63 float accelBias[3] = {0, 0, 0}; // Bias corrections for acc
BaserK 0:954f15bd95f1 64 float gyroBias[3] = {0, 0, 0}; // Bias corrections for gyro
BaserK 0:954f15bd95f1 65
BaserK 0:954f15bd95f1 66 // Specify sensor full scale range
BaserK 0:954f15bd95f1 67 int Ascale = AFS_2G;
BaserK 0:954f15bd95f1 68 int Gscale = GFS_250DPS;
BaserK 0:954f15bd95f1 69
BaserK 0:954f15bd95f1 70 // Scale resolutions per LSB for the sensors
BaserK 0:954f15bd95f1 71 float aRes, gRes;
BaserK 0:954f15bd95f1 72
BaserK 0:954f15bd95f1 73 // Calculates Acc resolution
BaserK 0:954f15bd95f1 74 void MPU6050::getAres()
BaserK 0:954f15bd95f1 75 {
BaserK 0:954f15bd95f1 76 switch(Ascale)
BaserK 0:954f15bd95f1 77 {
BaserK 0:954f15bd95f1 78 case AFS_2G:
BaserK 0:954f15bd95f1 79 aRes = 2.0/32768.0;
BaserK 0:954f15bd95f1 80 break;
BaserK 0:954f15bd95f1 81 case AFS_4G:
BaserK 0:954f15bd95f1 82 aRes = 4.0/32768.0;
BaserK 0:954f15bd95f1 83 break;
BaserK 0:954f15bd95f1 84 case AFS_8G:
BaserK 0:954f15bd95f1 85 aRes = 8.0/32768.0;
BaserK 0:954f15bd95f1 86 break;
BaserK 0:954f15bd95f1 87 case AFS_16G:
BaserK 0:954f15bd95f1 88 aRes = 16.0/32768.0;
BaserK 0:954f15bd95f1 89 break;
BaserK 0:954f15bd95f1 90 }
BaserK 0:954f15bd95f1 91 }
BaserK 0:954f15bd95f1 92
BaserK 0:954f15bd95f1 93 // Calculates Gyro resolution
BaserK 0:954f15bd95f1 94 void MPU6050::getGres()
BaserK 0:954f15bd95f1 95 {
BaserK 0:954f15bd95f1 96 switch(Gscale)
BaserK 0:954f15bd95f1 97 {
BaserK 0:954f15bd95f1 98 case GFS_250DPS:
BaserK 0:954f15bd95f1 99 gRes = 250.0/32768.0;
BaserK 0:954f15bd95f1 100 break;
BaserK 0:954f15bd95f1 101 case GFS_500DPS:
BaserK 0:954f15bd95f1 102 gRes = 500.0/32768.0;
BaserK 0:954f15bd95f1 103 break;
BaserK 0:954f15bd95f1 104 case GFS_1000DPS:
BaserK 0:954f15bd95f1 105 gRes = 1000.0/32768.0;
BaserK 0:954f15bd95f1 106 break;
BaserK 0:954f15bd95f1 107 case GFS_2000DPS:
BaserK 0:954f15bd95f1 108 gRes = 2000.0/32768.0;
BaserK 0:954f15bd95f1 109 break;
BaserK 0:954f15bd95f1 110 }
BaserK 0:954f15bd95f1 111 }
BaserK 0:954f15bd95f1 112
BaserK 0:954f15bd95f1 113 void MPU6050::writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
BaserK 0:954f15bd95f1 114 {
BaserK 0:954f15bd95f1 115 char data_write[2];
BaserK 0:954f15bd95f1 116 data_write[0]=subAddress; // I2C sends MSB first. Namely >>|subAddress|>>|data|
BaserK 0:954f15bd95f1 117 data_write[1]=data;
BaserK 0:954f15bd95f1 118 i2c.write(address,data_write,2,0); // i2c.write(int address, char* data, int length, bool repeated=false);
BaserK 0:954f15bd95f1 119 }
BaserK 0:954f15bd95f1 120
BaserK 0:954f15bd95f1 121 char MPU6050::readByte(uint8_t address, uint8_t subAddress)
BaserK 0:954f15bd95f1 122 {
BaserK 0:954f15bd95f1 123 char data_read[1]; // will store the register data
BaserK 0:954f15bd95f1 124 char data_write[1];
BaserK 0:954f15bd95f1 125 data_write[0]=subAddress;
BaserK 0:954f15bd95f1 126 i2c.write(address,data_write,1,1); // have not stopped yet
BaserK 0:954f15bd95f1 127 i2c.read(address,data_read,1,0); // read the data and stop
BaserK 0:954f15bd95f1 128 return data_read[0];
BaserK 0:954f15bd95f1 129 }
BaserK 0:954f15bd95f1 130
BaserK 0:954f15bd95f1 131 void MPU6050::readBytes(uint8_t address, uint8_t subAddress, uint8_t byteNum, uint8_t* dest)
BaserK 0:954f15bd95f1 132 {
BaserK 0:954f15bd95f1 133 char data[14],data_write[1];
BaserK 0:954f15bd95f1 134 data_write[0]=subAddress;
BaserK 0:954f15bd95f1 135 i2c.write(address,data_write,1,1);
BaserK 0:954f15bd95f1 136 i2c.read(address,data,byteNum,0);
BaserK 0:954f15bd95f1 137 for(int i=0;i<byteNum;i++) // equate the addresses
BaserK 0:954f15bd95f1 138 dest[i]=data[i];
BaserK 0:954f15bd95f1 139 }
BaserK 0:954f15bd95f1 140
BaserK 0:954f15bd95f1 141 // Communication test: WHO_AM_I register reading
BaserK 0:954f15bd95f1 142 void MPU6050::whoAmI()
BaserK 0:954f15bd95f1 143 {
BaserK 0:954f15bd95f1 144 uint8_t whoAmI = readByte(MPU6050_ADDRESS, WHO_AM_I_MPU6050); // Should return 0x68
BaserK 2:3e0dfce73a58 145 pc.printf("I AM 0x%x \r\n",whoAmI);
BaserK 0:954f15bd95f1 146
BaserK 0:954f15bd95f1 147 if(whoAmI==0x68)
BaserK 0:954f15bd95f1 148 {
BaserK 2:3e0dfce73a58 149 pc.printf("MPU6050 is online... \r\n");
BaserK 0:954f15bd95f1 150 led2=1;
BaserK 0:954f15bd95f1 151 }
BaserK 0:954f15bd95f1 152 else
BaserK 0:954f15bd95f1 153 {
BaserK 2:3e0dfce73a58 154 pc.printf("Could not connect to MPU6050 \r\nCheck the connections... \r\n");
BaserK 0:954f15bd95f1 155 toggler1.attach(&toggle_led1,0.1); // toggles led1 every 100 ms
BaserK 0:954f15bd95f1 156 }
BaserK 0:954f15bd95f1 157 }
BaserK 0:954f15bd95f1 158
BaserK 0:954f15bd95f1 159 // Initializes MPU6050 with the following config:
BaserK 0:954f15bd95f1 160 // PLL with X axis gyroscope reference
BaserK 0:954f15bd95f1 161 // Sample rate: 200Hz for gyro and acc
BaserK 0:954f15bd95f1 162 // Interrupts are disabled
BaserK 0:954f15bd95f1 163 void MPU6050::init()
BaserK 5:5bff0edcdff8 164 {
BaserK 5:5bff0edcdff8 165 i2c.frequency(400000); // fast i2c: 400 kHz
BaserK 5:5bff0edcdff8 166
BaserK 0:954f15bd95f1 167 /* Wake up the device */
BaserK 0:954f15bd95f1 168 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // wake up the device by clearing the sleep bit (bit6)
BaserK 0:954f15bd95f1 169 wait_ms(100); // wait 100 ms to stabilize
BaserK 0:954f15bd95f1 170
BaserK 0:954f15bd95f1 171 /* Get stable time source */
BaserK 0:954f15bd95f1 172 // PLL with X axis gyroscope reference is used to improve stability
BaserK 0:954f15bd95f1 173 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01);
BaserK 0:954f15bd95f1 174
BaserK 0:954f15bd95f1 175 /* Configure Gyroscope and Accelerometer */
BaserK 0:954f15bd95f1 176 // Disable FSYNC, acc bandwidth: 44 Hz, gyro bandwidth: 42 Hz
BaserK 0:954f15bd95f1 177 // Sample rates: 1kHz, maximum delay: 4.9ms (which is pretty good for a 200 Hz maximum rate)
BaserK 0:954f15bd95f1 178 writeByte(MPU6050_ADDRESS, CONFIG, 0x03);
BaserK 0:954f15bd95f1 179
BaserK 0:954f15bd95f1 180 /* Set sample rate = gyroscope output rate/(1+SMPLRT_DIV) */
BaserK 0:954f15bd95f1 181 // SMPLRT_DIV=4 and sample rate=200 Hz (compatible with config above)
BaserK 0:954f15bd95f1 182 writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x04);
BaserK 0:954f15bd95f1 183
BaserK 0:954f15bd95f1 184 /* Accelerometer configuration */
BaserK 0:954f15bd95f1 185 uint8_t temp = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
BaserK 0:954f15bd95f1 186 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, temp & ~0xE0); // Clear self-test bits [7:5]
BaserK 0:954f15bd95f1 187 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, temp & ~0x18); // Clear AFS bits [4:3]
BaserK 0:954f15bd95f1 188 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, temp | Ascale<<3); // Set full scale range
BaserK 0:954f15bd95f1 189
BaserK 0:954f15bd95f1 190 /* Gyroscope configuration */
BaserK 0:954f15bd95f1 191 temp = readByte(MPU6050_ADDRESS, GYRO_CONFIG);
BaserK 0:954f15bd95f1 192 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, temp & ~0xE0); // Clear self-test bits [7:5]
BaserK 0:954f15bd95f1 193 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, temp & ~0x18); // Clear FS bits [4:3]
BaserK 0:954f15bd95f1 194 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, temp | Gscale<<3); // Set full scale range
BaserK 0:954f15bd95f1 195 }
BaserK 0:954f15bd95f1 196
BaserK 0:954f15bd95f1 197 // Resets the device
BaserK 0:954f15bd95f1 198 void MPU6050::reset()
BaserK 0:954f15bd95f1 199 {
BaserK 0:954f15bd95f1 200 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // set bit7 to reset the device
BaserK 0:954f15bd95f1 201 wait_ms(100); // wait 100 ms to stabilize
BaserK 0:954f15bd95f1 202 }
BaserK 0:954f15bd95f1 203
BaserK 0:954f15bd95f1 204 void MPU6050::readAccelData(int16_t* dest)
BaserK 0:954f15bd95f1 205 {
BaserK 0:954f15bd95f1 206 uint8_t rawData[6]; // x,y,z acc data
BaserK 0:954f15bd95f1 207 readBytes(MPU6050_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // read six raw data registers sequentially and write them into data array
BaserK 0:954f15bd95f1 208
BaserK 0:954f15bd95f1 209 /* Turn the MSB LSB into signed 16-bit value */
BaserK 0:954f15bd95f1 210 dest[0] = (int16_t)(((int16_t)rawData[0]<<8) | rawData[1]); // ACCEL_XOUT
BaserK 0:954f15bd95f1 211 dest[1] = (int16_t)(((int16_t)rawData[2]<<8) | rawData[3]); // ACCEL_YOUT
BaserK 0:954f15bd95f1 212 dest[2] = (int16_t)(((int16_t)rawData[4]<<8) | rawData[5]); // ACCEL_ZOUT
BaserK 0:954f15bd95f1 213 }
BaserK 0:954f15bd95f1 214
BaserK 0:954f15bd95f1 215 void MPU6050::readGyroData(int16_t* dest)
BaserK 0:954f15bd95f1 216 {
BaserK 0:954f15bd95f1 217 uint8_t rawData[6]; // x,y,z gyro data
BaserK 0:954f15bd95f1 218 readBytes(MPU6050_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // read the six raw data registers sequentially and write them into data array
BaserK 0:954f15bd95f1 219
BaserK 0:954f15bd95f1 220 /* Turn the MSB LSB into signed 16-bit value */
BaserK 0:954f15bd95f1 221 dest[0] = (int16_t)(((int16_t)rawData[0]<<8) | rawData[1]); // GYRO_XOUT
BaserK 0:954f15bd95f1 222 dest[1] = (int16_t)(((int16_t)rawData[2]<<8) | rawData[3]); // GYRO_YOUT
BaserK 0:954f15bd95f1 223 dest[2] = (int16_t)(((int16_t)rawData[4]<<8) | rawData[5]); // GYRO_ZOUT
BaserK 0:954f15bd95f1 224 }
BaserK 0:954f15bd95f1 225
BaserK 0:954f15bd95f1 226 int16_t MPU6050::readTempData()
BaserK 0:954f15bd95f1 227 {
BaserK 0:954f15bd95f1 228 uint8_t rawData[2]; // temperature data
BaserK 0:954f15bd95f1 229 readBytes(MPU6050_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // read the two raw data registers sequentially and write them into data array
BaserK 0:954f15bd95f1 230 return (int16_t)(((int16_t)rawData[0]<<8) | rawData[1]); // turn the MSB LSB into signed 16-bit value
BaserK 0:954f15bd95f1 231 }
BaserK 0:954f15bd95f1 232
BaserK 0:954f15bd95f1 233 /* Function which accumulates gyro and accelerometer data after device initialization.
BaserK 0:954f15bd95f1 234 It calculates the average of the at-rest readings and
BaserK 0:954f15bd95f1 235 then loads the resulting offsets into accelerometer and gyro bias registers. */
BaserK 0:954f15bd95f1 236 /*
BaserK 0:954f15bd95f1 237 IMPORTANT NOTE: In this function;
BaserK 0:954f15bd95f1 238 Resulting accel offsets are NOT pushed to the accel bias registers. accelBias[i] offsets are used in the main program.
BaserK 0:954f15bd95f1 239 Resulting gyro offsets are pushed to the gyro bias registers. gyroBias[i] offsets are NOT used in the main program.
BaserK 0:954f15bd95f1 240 Resulting data seems satisfactory.
BaserK 0:954f15bd95f1 241 */
BaserK 0:954f15bd95f1 242 // dest1: accelBias dest2: gyroBias
BaserK 0:954f15bd95f1 243 void MPU6050::calibrate(float* dest1, float* dest2)
BaserK 0:954f15bd95f1 244 {
BaserK 0:954f15bd95f1 245 uint8_t data[12]; // data array to hold acc and gyro x,y,z data
BaserK 0:954f15bd95f1 246 uint16_t fifo_count, packet_count, count;
BaserK 0:954f15bd95f1 247 int32_t accel_bias[3] = {0,0,0};
BaserK 0:954f15bd95f1 248 int32_t gyro_bias[3] = {0,0,0};
BaserK 0:954f15bd95f1 249 float aRes = 2.0/32768.0;
BaserK 0:954f15bd95f1 250 float gRes = 250.0/32768.0;
BaserK 0:954f15bd95f1 251 uint16_t accelsensitivity = 16384; // = 1/aRes = 16384 LSB/g
BaserK 0:954f15bd95f1 252 //uint16_t gyrosensitivity = 131; // = 1/gRes = 131 LSB/dps
BaserK 0:954f15bd95f1 253
BaserK 0:954f15bd95f1 254 reset(); // Reset device
BaserK 0:954f15bd95f1 255
BaserK 0:954f15bd95f1 256 /* Get stable time source */
BaserK 0:954f15bd95f1 257 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01); // PLL with X axis gyroscope reference is used to improve stability
BaserK 0:954f15bd95f1 258 writeByte(MPU6050_ADDRESS, PWR_MGMT_2, 0x00); // Disable accel only low power mode
BaserK 0:954f15bd95f1 259 wait(0.2);
BaserK 0:954f15bd95f1 260
BaserK 0:954f15bd95f1 261 /* Configure device for bias calculation */
BaserK 0:954f15bd95f1 262 writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts
BaserK 0:954f15bd95f1 263 writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
BaserK 0:954f15bd95f1 264 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source
BaserK 0:954f15bd95f1 265 writeByte(MPU6050_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master
BaserK 0:954f15bd95f1 266 writeByte(MPU6050_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes
BaserK 0:954f15bd95f1 267 writeByte(MPU6050_ADDRESS, USER_CTRL, 0x04); // Reset FIFO
BaserK 0:954f15bd95f1 268 wait(0.015);
BaserK 0:954f15bd95f1 269
BaserK 0:954f15bd95f1 270 /* Configure accel and gyro for bias calculation */
BaserK 0:954f15bd95f1 271 writeByte(MPU6050_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz
BaserK 0:954f15bd95f1 272 writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz
BaserK 0:954f15bd95f1 273 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity
BaserK 0:954f15bd95f1 274 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity
BaserK 0:954f15bd95f1 275
BaserK 0:954f15bd95f1 276 /* Configure FIFO to capture accelerometer and gyro data for bias calculation */
BaserK 0:954f15bd95f1 277 writeByte(MPU6050_ADDRESS, USER_CTRL, 0x40); // Enable FIFO
BaserK 0:954f15bd95f1 278 writeByte(MPU6050_ADDRESS, FIFO_EN, 0x78); // Enable accelerometer and gyro for FIFO (max size 1024 bytes in MPU-6050)
BaserK 0:954f15bd95f1 279 wait(0.08); // Sample rate is 1 kHz, accumulates 80 samples in 80 milliseconds.
BaserK 0:954f15bd95f1 280 // accX: 2 byte, accY: 2 byte, accZ: 2 byte. gyroX: 2 byte, gyroY: 2 byte, gyroZ: 2 byte. 12*80=960 byte < 1024 byte
BaserK 0:954f15bd95f1 281
BaserK 0:954f15bd95f1 282 /* At end of sample accumulation, turn off FIFO sensor read */
BaserK 0:954f15bd95f1 283 writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
BaserK 0:954f15bd95f1 284 readBytes(MPU6050_ADDRESS, FIFO_COUNTH, 2, &data[0]); // Read FIFO sample count
BaserK 0:954f15bd95f1 285 fifo_count = ((uint16_t)data[0] << 8) | data[1];
BaserK 0:954f15bd95f1 286 packet_count = fifo_count/12; // The number of sets of full acc and gyro data for averaging. packet_count = 80 in this case
BaserK 0:954f15bd95f1 287
BaserK 0:954f15bd95f1 288 for(count=0; count<packet_count; count++)
BaserK 0:954f15bd95f1 289 {
BaserK 0:954f15bd95f1 290 int16_t accel_temp[3]={0,0,0};
BaserK 0:954f15bd95f1 291 int16_t gyro_temp[3]={0,0,0};
BaserK 0:954f15bd95f1 292 readBytes(MPU6050_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging
BaserK 0:954f15bd95f1 293
BaserK 0:954f15bd95f1 294 /* Form signed 16-bit integer for each sample in FIFO */
BaserK 0:954f15bd95f1 295 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ;
BaserK 0:954f15bd95f1 296 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ;
BaserK 0:954f15bd95f1 297 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ;
BaserK 0:954f15bd95f1 298 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ;
BaserK 0:954f15bd95f1 299 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ;
BaserK 0:954f15bd95f1 300 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ;
BaserK 0:954f15bd95f1 301
BaserK 0:954f15bd95f1 302 /* Sum individual signed 16-bit biases to get accumulated signed 32-bit biases */
BaserK 0:954f15bd95f1 303 accel_bias[0] += (int32_t) accel_temp[0];
BaserK 0:954f15bd95f1 304 accel_bias[1] += (int32_t) accel_temp[1];
BaserK 0:954f15bd95f1 305 accel_bias[2] += (int32_t) accel_temp[2];
BaserK 0:954f15bd95f1 306 gyro_bias[0] += (int32_t) gyro_temp[0];
BaserK 0:954f15bd95f1 307 gyro_bias[1] += (int32_t) gyro_temp[1];
BaserK 0:954f15bd95f1 308 gyro_bias[2] += (int32_t) gyro_temp[2];
BaserK 0:954f15bd95f1 309 }
BaserK 0:954f15bd95f1 310
BaserK 0:954f15bd95f1 311 /* Normalize sums to get average count biases */
BaserK 0:954f15bd95f1 312 accel_bias[0] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 313 accel_bias[1] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 314 accel_bias[2] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 315 gyro_bias[0] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 316 gyro_bias[1] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 317 gyro_bias[2] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 318
BaserK 0:954f15bd95f1 319 /* Remove gravity from the z-axis accelerometer bias calculation */
BaserK 0:954f15bd95f1 320 if(accel_bias[2] > 0) {accel_bias[2] -= (int32_t) accelsensitivity;}
BaserK 0:954f15bd95f1 321 else {accel_bias[2] += (int32_t) accelsensitivity;}
BaserK 0:954f15bd95f1 322
BaserK 0:954f15bd95f1 323 /* Output scaled accelerometer biases for manual subtraction in the main program */
BaserK 0:954f15bd95f1 324 dest1[0] = accel_bias[0]*aRes;
BaserK 0:954f15bd95f1 325 dest1[1] = accel_bias[1]*aRes;
BaserK 0:954f15bd95f1 326 dest1[2] = accel_bias[2]*aRes;
BaserK 0:954f15bd95f1 327
BaserK 0:954f15bd95f1 328 /* Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup */
BaserK 0:954f15bd95f1 329 data[0] = (-gyro_bias[0]/4 >> 8) & 0xFF; // Divide by 4 to get 32.9 LSB per deg/s to conform to expected bias input format
BaserK 0:954f15bd95f1 330 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases
BaserK 0:954f15bd95f1 331 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF;
BaserK 0:954f15bd95f1 332 data[3] = (-gyro_bias[1]/4) & 0xFF;
BaserK 0:954f15bd95f1 333 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF;
BaserK 0:954f15bd95f1 334 data[5] = (-gyro_bias[2]/4) & 0xFF;
BaserK 0:954f15bd95f1 335
BaserK 0:954f15bd95f1 336 /* Push gyro biases to hardware registers */
BaserK 0:954f15bd95f1 337 writeByte(MPU6050_ADDRESS, XG_OFFS_USRH, data[0]);
BaserK 0:954f15bd95f1 338 writeByte(MPU6050_ADDRESS, XG_OFFS_USRL, data[1]);
BaserK 0:954f15bd95f1 339 writeByte(MPU6050_ADDRESS, YG_OFFS_USRH, data[2]);
BaserK 0:954f15bd95f1 340 writeByte(MPU6050_ADDRESS, YG_OFFS_USRL, data[3]);
BaserK 0:954f15bd95f1 341 writeByte(MPU6050_ADDRESS, ZG_OFFS_USRH, data[4]);
BaserK 0:954f15bd95f1 342 writeByte(MPU6050_ADDRESS, ZG_OFFS_USRL, data[5]);
BaserK 0:954f15bd95f1 343
BaserK 0:954f15bd95f1 344 /* Construct gyro bias in deg/s for later manual subtraction */
BaserK 0:954f15bd95f1 345 dest2[0] = gyro_bias[0]*gRes;
BaserK 0:954f15bd95f1 346 dest2[1] = gyro_bias[1]*gRes;
BaserK 0:954f15bd95f1 347 dest2[2] = gyro_bias[2]*gRes;
BaserK 0:954f15bd95f1 348 }
BaserK 2:3e0dfce73a58 349
BaserK 2:3e0dfce73a58 350 void MPU6050::complementaryFilter(float* pitch, float* roll)
BaserK 2:3e0dfce73a58 351 {
BaserK 2:3e0dfce73a58 352 /* Get actual acc value */
BaserK 2:3e0dfce73a58 353 readAccelData(accelData);
BaserK 2:3e0dfce73a58 354 getAres();
BaserK 2:3e0dfce73a58 355 ax = accelData[0]*aRes - accelBias[0];
BaserK 2:3e0dfce73a58 356 ay = accelData[1]*aRes - accelBias[1];
BaserK 2:3e0dfce73a58 357 az = accelData[2]*aRes - accelBias[2];
BaserK 2:3e0dfce73a58 358
BaserK 2:3e0dfce73a58 359 /* Get actual gyro value */
BaserK 2:3e0dfce73a58 360 readGyroData(gyroData);
BaserK 2:3e0dfce73a58 361 getGres();
BaserK 2:3e0dfce73a58 362 gx = gyroData[0]*gRes; // - gyroBias[0]; // Results are better without extracting gyroBias[i]
BaserK 2:3e0dfce73a58 363 gy = gyroData[1]*gRes; // - gyroBias[1];
BaserK 2:3e0dfce73a58 364 gz = gyroData[2]*gRes; // - gyroBias[2];
BaserK 2:3e0dfce73a58 365
BaserK 2:3e0dfce73a58 366 float pitchAcc, rollAcc;
BaserK 2:3e0dfce73a58 367
BaserK 2:3e0dfce73a58 368 /* Integrate the gyro data(deg/s) over time to get angle */
BaserK 2:3e0dfce73a58 369 *pitch += gx * dt; // Angle around the X-axis
BaserK 2:3e0dfce73a58 370 *roll -= gy * dt; // Angle around the Y-axis
BaserK 2:3e0dfce73a58 371
BaserK 2:3e0dfce73a58 372 /* Turning around the X-axis results in a vector on the Y-axis
BaserK 2:3e0dfce73a58 373 whereas turning around the Y-axis results in a vector on the X-axis. */
BaserK 2:3e0dfce73a58 374 pitchAcc = atan2f(accelData[1], accelData[2])*180/PI;
BaserK 2:3e0dfce73a58 375 rollAcc = atan2f(accelData[0], accelData[2])*180/PI;
BaserK 2:3e0dfce73a58 376
BaserK 2:3e0dfce73a58 377 /* Apply Complementary Filter */
BaserK 2:3e0dfce73a58 378 *pitch = *pitch * 0.98 + pitchAcc * 0.02;
BaserK 2:3e0dfce73a58 379 *roll = *roll * 0.98 + rollAcc * 0.02;
BaserK 2:3e0dfce73a58 380 }