Lakshmanan Gopalakrishnan / MPU6050

First trial of Balancing robot based on Kristian Lauszus's code.

Dependents:   Balancing_Robot_2

Fork of MPU6050 by Baser Kandehir

MPU6050.cpp@3:a173ad187e67, 2015-07-21 (annotated)

Committer:
BaserK
Date:
Tue Jul 21 08:16:36 2015 +0000
Revision:
3:a173ad187e67
Parent:
2:3e0dfce73a58
Child:
4:20f1f660e5c3
MIT license is added

Who changed what in which revision?

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