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@0:954f15bd95f1, 2015-07-09 (annotated)

Committer:
BaserK
Date:
Thu Jul 09 12:13:56 2015 +0000
Revision:
0:954f15bd95f1
Child:
2:3e0dfce73a58
First commit for this library;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
BaserK 0:954f15bd95f1 1 /* @author: Baser Kandehir
BaserK 0:954f15bd95f1 2 * @date: July 9, 2015
BaserK 0:954f15bd95f1 3 * @license: Use this code however you'd like
BaserK 0:954f15bd95f1 4 */
BaserK 0:954f15bd95f1 5
BaserK 0:954f15bd95f1 6 // Most of the code is adapted from Kris Winer's MPU6050 library
BaserK 0:954f15bd95f1 7
BaserK 0:954f15bd95f1 8 #include "MPU6050.h"
BaserK 0:954f15bd95f1 9
BaserK 0:954f15bd95f1 10 I2C i2c(p9,p10); // setup i2c (SDA,SCL)
BaserK 0:954f15bd95f1 11
BaserK 0:954f15bd95f1 12 /* Set initial input parameters */
BaserK 0:954f15bd95f1 13
BaserK 0:954f15bd95f1 14 // Acc Full Scale Range +-2G 4G 8G 16G
BaserK 0:954f15bd95f1 15 enum Ascale
BaserK 0:954f15bd95f1 16 {
BaserK 0:954f15bd95f1 17 AFS_2G=0,
BaserK 0:954f15bd95f1 18 AFS_4G,
BaserK 0:954f15bd95f1 19 AFS_8G,
BaserK 0:954f15bd95f1 20 AFS_16G
BaserK 0:954f15bd95f1 21 };
BaserK 0:954f15bd95f1 22
BaserK 0:954f15bd95f1 23 // Gyro Full Scale Range +-250 500 1000 2000 Degrees per second
BaserK 0:954f15bd95f1 24 enum Gscale
BaserK 0:954f15bd95f1 25 {
BaserK 0:954f15bd95f1 26 GFS_250DPS=0,
BaserK 0:954f15bd95f1 27 GFS_500DPS,
BaserK 0:954f15bd95f1 28 GFS_1000DPS,
BaserK 0:954f15bd95f1 29 GFS_2000DPS
BaserK 0:954f15bd95f1 30 };
BaserK 0:954f15bd95f1 31
BaserK 0:954f15bd95f1 32 // Sensor datas
BaserK 0:954f15bd95f1 33 float ax,ay,az;
BaserK 0:954f15bd95f1 34 float gx,gy,gz;
BaserK 0:954f15bd95f1 35 int16_t accelData[3],gyroData[3],tempData;
BaserK 0:954f15bd95f1 36 float accelBias[3] = {0, 0, 0}; // Bias corrections for acc
BaserK 0:954f15bd95f1 37 float gyroBias[3] = {0, 0, 0}; // Bias corrections for gyro
BaserK 0:954f15bd95f1 38
BaserK 0:954f15bd95f1 39 // Specify sensor full scale range
BaserK 0:954f15bd95f1 40 int Ascale = AFS_2G;
BaserK 0:954f15bd95f1 41 int Gscale = GFS_250DPS;
BaserK 0:954f15bd95f1 42
BaserK 0:954f15bd95f1 43 // Scale resolutions per LSB for the sensors
BaserK 0:954f15bd95f1 44 float aRes, gRes;
BaserK 0:954f15bd95f1 45
BaserK 0:954f15bd95f1 46 // Calculates Acc resolution
BaserK 0:954f15bd95f1 47 void MPU6050::getAres()
BaserK 0:954f15bd95f1 48 {
BaserK 0:954f15bd95f1 49 switch(Ascale)
BaserK 0:954f15bd95f1 50 {
BaserK 0:954f15bd95f1 51 case AFS_2G:
BaserK 0:954f15bd95f1 52 aRes = 2.0/32768.0;
BaserK 0:954f15bd95f1 53 break;
BaserK 0:954f15bd95f1 54 case AFS_4G:
BaserK 0:954f15bd95f1 55 aRes = 4.0/32768.0;
BaserK 0:954f15bd95f1 56 break;
BaserK 0:954f15bd95f1 57 case AFS_8G:
BaserK 0:954f15bd95f1 58 aRes = 8.0/32768.0;
BaserK 0:954f15bd95f1 59 break;
BaserK 0:954f15bd95f1 60 case AFS_16G:
BaserK 0:954f15bd95f1 61 aRes = 16.0/32768.0;
BaserK 0:954f15bd95f1 62 break;
BaserK 0:954f15bd95f1 63 }
BaserK 0:954f15bd95f1 64 }
BaserK 0:954f15bd95f1 65
BaserK 0:954f15bd95f1 66 // Calculates Gyro resolution
BaserK 0:954f15bd95f1 67 void MPU6050::getGres()
BaserK 0:954f15bd95f1 68 {
BaserK 0:954f15bd95f1 69 switch(Gscale)
BaserK 0:954f15bd95f1 70 {
BaserK 0:954f15bd95f1 71 case GFS_250DPS:
BaserK 0:954f15bd95f1 72 gRes = 250.0/32768.0;
BaserK 0:954f15bd95f1 73 break;
BaserK 0:954f15bd95f1 74 case GFS_500DPS:
BaserK 0:954f15bd95f1 75 gRes = 500.0/32768.0;
BaserK 0:954f15bd95f1 76 break;
BaserK 0:954f15bd95f1 77 case GFS_1000DPS:
BaserK 0:954f15bd95f1 78 gRes = 1000.0/32768.0;
BaserK 0:954f15bd95f1 79 break;
BaserK 0:954f15bd95f1 80 case GFS_2000DPS:
BaserK 0:954f15bd95f1 81 gRes = 2000.0/32768.0;
BaserK 0:954f15bd95f1 82 break;
BaserK 0:954f15bd95f1 83 }
BaserK 0:954f15bd95f1 84 }
BaserK 0:954f15bd95f1 85
BaserK 0:954f15bd95f1 86 void MPU6050::writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
BaserK 0:954f15bd95f1 87 {
BaserK 0:954f15bd95f1 88 char data_write[2];
BaserK 0:954f15bd95f1 89 data_write[0]=subAddress; // I2C sends MSB first. Namely >>|subAddress|>>|data|
BaserK 0:954f15bd95f1 90 data_write[1]=data;
BaserK 0:954f15bd95f1 91 i2c.write(address,data_write,2,0); // i2c.write(int address, char* data, int length, bool repeated=false);
BaserK 0:954f15bd95f1 92 }
BaserK 0:954f15bd95f1 93
BaserK 0:954f15bd95f1 94 char MPU6050::readByte(uint8_t address, uint8_t subAddress)
BaserK 0:954f15bd95f1 95 {
BaserK 0:954f15bd95f1 96 char data_read[1]; // will store the register data
BaserK 0:954f15bd95f1 97 char data_write[1];
BaserK 0:954f15bd95f1 98 data_write[0]=subAddress;
BaserK 0:954f15bd95f1 99 i2c.write(address,data_write,1,1); // have not stopped yet
BaserK 0:954f15bd95f1 100 i2c.read(address,data_read,1,0); // read the data and stop
BaserK 0:954f15bd95f1 101 return data_read[0];
BaserK 0:954f15bd95f1 102 }
BaserK 0:954f15bd95f1 103
BaserK 0:954f15bd95f1 104 void MPU6050::readBytes(uint8_t address, uint8_t subAddress, uint8_t byteNum, uint8_t* dest)
BaserK 0:954f15bd95f1 105 {
BaserK 0:954f15bd95f1 106 char data[14],data_write[1];
BaserK 0:954f15bd95f1 107 data_write[0]=subAddress;
BaserK 0:954f15bd95f1 108 i2c.write(address,data_write,1,1);
BaserK 0:954f15bd95f1 109 i2c.read(address,data,byteNum,0);
BaserK 0:954f15bd95f1 110 for(int i=0;i<byteNum;i++) // equate the addresses
BaserK 0:954f15bd95f1 111 dest[i]=data[i];
BaserK 0:954f15bd95f1 112 }
BaserK 0:954f15bd95f1 113
BaserK 0:954f15bd95f1 114 // Communication test: WHO_AM_I register reading
BaserK 0:954f15bd95f1 115 void MPU6050::whoAmI()
BaserK 0:954f15bd95f1 116 {
BaserK 0:954f15bd95f1 117 uint8_t whoAmI = readByte(MPU6050_ADDRESS, WHO_AM_I_MPU6050); // Should return 0x68
BaserK 0:954f15bd95f1 118 ftdi.printf("I AM 0x%x \r\n",whoAmI);
BaserK 0:954f15bd95f1 119
BaserK 0:954f15bd95f1 120 if(whoAmI==0x68)
BaserK 0:954f15bd95f1 121 {
BaserK 0:954f15bd95f1 122 ftdi.printf("MPU6050 is online... \r\n");
BaserK 0:954f15bd95f1 123 led2=1;
BaserK 0:954f15bd95f1 124 }
BaserK 0:954f15bd95f1 125 else
BaserK 0:954f15bd95f1 126 {
BaserK 0:954f15bd95f1 127 ftdi.printf("Could not connect to MPU6050 \r\nCheck the connections... \r\n");
BaserK 0:954f15bd95f1 128 toggler1.attach(&toggle_led1,0.1); // toggles led1 every 100 ms
BaserK 0:954f15bd95f1 129 }
BaserK 0:954f15bd95f1 130 }
BaserK 0:954f15bd95f1 131
BaserK 0:954f15bd95f1 132 // Initializes MPU6050 with the following config:
BaserK 0:954f15bd95f1 133 // PLL with X axis gyroscope reference
BaserK 0:954f15bd95f1 134 // Sample rate: 200Hz for gyro and acc
BaserK 0:954f15bd95f1 135 // Interrupts are disabled
BaserK 0:954f15bd95f1 136 void MPU6050::init()
BaserK 0:954f15bd95f1 137 {
BaserK 0:954f15bd95f1 138 /* Wake up the device */
BaserK 0:954f15bd95f1 139 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // wake up the device by clearing the sleep bit (bit6)
BaserK 0:954f15bd95f1 140 wait_ms(100); // wait 100 ms to stabilize
BaserK 0:954f15bd95f1 141
BaserK 0:954f15bd95f1 142 /* Get stable time source */
BaserK 0:954f15bd95f1 143 // PLL with X axis gyroscope reference is used to improve stability
BaserK 0:954f15bd95f1 144 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01);
BaserK 0:954f15bd95f1 145
BaserK 0:954f15bd95f1 146 /* Configure Gyroscope and Accelerometer */
BaserK 0:954f15bd95f1 147 // Disable FSYNC, acc bandwidth: 44 Hz, gyro bandwidth: 42 Hz
BaserK 0:954f15bd95f1 148 // Sample rates: 1kHz, maximum delay: 4.9ms (which is pretty good for a 200 Hz maximum rate)
BaserK 0:954f15bd95f1 149 writeByte(MPU6050_ADDRESS, CONFIG, 0x03);
BaserK 0:954f15bd95f1 150
BaserK 0:954f15bd95f1 151 /* Set sample rate = gyroscope output rate/(1+SMPLRT_DIV) */
BaserK 0:954f15bd95f1 152 // SMPLRT_DIV=4 and sample rate=200 Hz (compatible with config above)
BaserK 0:954f15bd95f1 153 writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x04);
BaserK 0:954f15bd95f1 154
BaserK 0:954f15bd95f1 155 /* Accelerometer configuration */
BaserK 0:954f15bd95f1 156 uint8_t temp = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
BaserK 0:954f15bd95f1 157 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, temp & ~0xE0); // Clear self-test bits [7:5]
BaserK 0:954f15bd95f1 158 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, temp & ~0x18); // Clear AFS bits [4:3]
BaserK 0:954f15bd95f1 159 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, temp | Ascale<<3); // Set full scale range
BaserK 0:954f15bd95f1 160
BaserK 0:954f15bd95f1 161 /* Gyroscope configuration */
BaserK 0:954f15bd95f1 162 temp = readByte(MPU6050_ADDRESS, GYRO_CONFIG);
BaserK 0:954f15bd95f1 163 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, temp & ~0xE0); // Clear self-test bits [7:5]
BaserK 0:954f15bd95f1 164 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, temp & ~0x18); // Clear FS bits [4:3]
BaserK 0:954f15bd95f1 165 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, temp | Gscale<<3); // Set full scale range
BaserK 0:954f15bd95f1 166 }
BaserK 0:954f15bd95f1 167
BaserK 0:954f15bd95f1 168 // Resets the device
BaserK 0:954f15bd95f1 169 void MPU6050::reset()
BaserK 0:954f15bd95f1 170 {
BaserK 0:954f15bd95f1 171 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // set bit7 to reset the device
BaserK 0:954f15bd95f1 172 wait_ms(100); // wait 100 ms to stabilize
BaserK 0:954f15bd95f1 173 }
BaserK 0:954f15bd95f1 174
BaserK 0:954f15bd95f1 175 void MPU6050::readAccelData(int16_t* dest)
BaserK 0:954f15bd95f1 176 {
BaserK 0:954f15bd95f1 177 uint8_t rawData[6]; // x,y,z acc data
BaserK 0:954f15bd95f1 178 readBytes(MPU6050_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // read six raw data registers sequentially and write them into data array
BaserK 0:954f15bd95f1 179
BaserK 0:954f15bd95f1 180 /* Turn the MSB LSB into signed 16-bit value */
BaserK 0:954f15bd95f1 181 dest[0] = (int16_t)(((int16_t)rawData[0]<<8) | rawData[1]); // ACCEL_XOUT
BaserK 0:954f15bd95f1 182 dest[1] = (int16_t)(((int16_t)rawData[2]<<8) | rawData[3]); // ACCEL_YOUT
BaserK 0:954f15bd95f1 183 dest[2] = (int16_t)(((int16_t)rawData[4]<<8) | rawData[5]); // ACCEL_ZOUT
BaserK 0:954f15bd95f1 184 }
BaserK 0:954f15bd95f1 185
BaserK 0:954f15bd95f1 186 void MPU6050::readGyroData(int16_t* dest)
BaserK 0:954f15bd95f1 187 {
BaserK 0:954f15bd95f1 188 uint8_t rawData[6]; // x,y,z gyro data
BaserK 0:954f15bd95f1 189 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 190
BaserK 0:954f15bd95f1 191 /* Turn the MSB LSB into signed 16-bit value */
BaserK 0:954f15bd95f1 192 dest[0] = (int16_t)(((int16_t)rawData[0]<<8) | rawData[1]); // GYRO_XOUT
BaserK 0:954f15bd95f1 193 dest[1] = (int16_t)(((int16_t)rawData[2]<<8) | rawData[3]); // GYRO_YOUT
BaserK 0:954f15bd95f1 194 dest[2] = (int16_t)(((int16_t)rawData[4]<<8) | rawData[5]); // GYRO_ZOUT
BaserK 0:954f15bd95f1 195 }
BaserK 0:954f15bd95f1 196
BaserK 0:954f15bd95f1 197 int16_t MPU6050::readTempData()
BaserK 0:954f15bd95f1 198 {
BaserK 0:954f15bd95f1 199 uint8_t rawData[2]; // temperature data
BaserK 0:954f15bd95f1 200 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 201 return (int16_t)(((int16_t)rawData[0]<<8) | rawData[1]); // turn the MSB LSB into signed 16-bit value
BaserK 0:954f15bd95f1 202 }
BaserK 0:954f15bd95f1 203
BaserK 0:954f15bd95f1 204 /* Function which accumulates gyro and accelerometer data after device initialization.
BaserK 0:954f15bd95f1 205 It calculates the average of the at-rest readings and
BaserK 0:954f15bd95f1 206 then loads the resulting offsets into accelerometer and gyro bias registers. */
BaserK 0:954f15bd95f1 207 /*
BaserK 0:954f15bd95f1 208 IMPORTANT NOTE: In this function;
BaserK 0:954f15bd95f1 209 Resulting accel offsets are NOT pushed to the accel bias registers. accelBias[i] offsets are used in the main program.
BaserK 0:954f15bd95f1 210 Resulting gyro offsets are pushed to the gyro bias registers. gyroBias[i] offsets are NOT used in the main program.
BaserK 0:954f15bd95f1 211 Resulting data seems satisfactory.
BaserK 0:954f15bd95f1 212 */
BaserK 0:954f15bd95f1 213 // dest1: accelBias dest2: gyroBias
BaserK 0:954f15bd95f1 214 void MPU6050::calibrate(float* dest1, float* dest2)
BaserK 0:954f15bd95f1 215 {
BaserK 0:954f15bd95f1 216 uint8_t data[12]; // data array to hold acc and gyro x,y,z data
BaserK 0:954f15bd95f1 217 uint16_t fifo_count, packet_count, count;
BaserK 0:954f15bd95f1 218 int32_t accel_bias[3] = {0,0,0};
BaserK 0:954f15bd95f1 219 int32_t gyro_bias[3] = {0,0,0};
BaserK 0:954f15bd95f1 220 float aRes = 2.0/32768.0;
BaserK 0:954f15bd95f1 221 float gRes = 250.0/32768.0;
BaserK 0:954f15bd95f1 222 uint16_t accelsensitivity = 16384; // = 1/aRes = 16384 LSB/g
BaserK 0:954f15bd95f1 223 //uint16_t gyrosensitivity = 131; // = 1/gRes = 131 LSB/dps
BaserK 0:954f15bd95f1 224
BaserK 0:954f15bd95f1 225 reset(); // Reset device
BaserK 0:954f15bd95f1 226
BaserK 0:954f15bd95f1 227 /* Get stable time source */
BaserK 0:954f15bd95f1 228 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01); // PLL with X axis gyroscope reference is used to improve stability
BaserK 0:954f15bd95f1 229 writeByte(MPU6050_ADDRESS, PWR_MGMT_2, 0x00); // Disable accel only low power mode
BaserK 0:954f15bd95f1 230 wait(0.2);
BaserK 0:954f15bd95f1 231
BaserK 0:954f15bd95f1 232 /* Configure device for bias calculation */
BaserK 0:954f15bd95f1 233 writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts
BaserK 0:954f15bd95f1 234 writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
BaserK 0:954f15bd95f1 235 writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source
BaserK 0:954f15bd95f1 236 writeByte(MPU6050_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master
BaserK 0:954f15bd95f1 237 writeByte(MPU6050_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes
BaserK 0:954f15bd95f1 238 writeByte(MPU6050_ADDRESS, USER_CTRL, 0x04); // Reset FIFO
BaserK 0:954f15bd95f1 239 wait(0.015);
BaserK 0:954f15bd95f1 240
BaserK 0:954f15bd95f1 241 /* Configure accel and gyro for bias calculation */
BaserK 0:954f15bd95f1 242 writeByte(MPU6050_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz
BaserK 0:954f15bd95f1 243 writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz
BaserK 0:954f15bd95f1 244 writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity
BaserK 0:954f15bd95f1 245 writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity
BaserK 0:954f15bd95f1 246
BaserK 0:954f15bd95f1 247 /* Configure FIFO to capture accelerometer and gyro data for bias calculation */
BaserK 0:954f15bd95f1 248 writeByte(MPU6050_ADDRESS, USER_CTRL, 0x40); // Enable FIFO
BaserK 0:954f15bd95f1 249 writeByte(MPU6050_ADDRESS, FIFO_EN, 0x78); // Enable accelerometer and gyro for FIFO (max size 1024 bytes in MPU-6050)
BaserK 0:954f15bd95f1 250 wait(0.08); // Sample rate is 1 kHz, accumulates 80 samples in 80 milliseconds.
BaserK 0:954f15bd95f1 251 // 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 252
BaserK 0:954f15bd95f1 253 /* At end of sample accumulation, turn off FIFO sensor read */
BaserK 0:954f15bd95f1 254 writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
BaserK 0:954f15bd95f1 255 readBytes(MPU6050_ADDRESS, FIFO_COUNTH, 2, &data[0]); // Read FIFO sample count
BaserK 0:954f15bd95f1 256 fifo_count = ((uint16_t)data[0] << 8) | data[1];
BaserK 0:954f15bd95f1 257 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 258
BaserK 0:954f15bd95f1 259 for(count=0; count<packet_count; count++)
BaserK 0:954f15bd95f1 260 {
BaserK 0:954f15bd95f1 261 int16_t accel_temp[3]={0,0,0};
BaserK 0:954f15bd95f1 262 int16_t gyro_temp[3]={0,0,0};
BaserK 0:954f15bd95f1 263 readBytes(MPU6050_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging
BaserK 0:954f15bd95f1 264
BaserK 0:954f15bd95f1 265 /* Form signed 16-bit integer for each sample in FIFO */
BaserK 0:954f15bd95f1 266 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ;
BaserK 0:954f15bd95f1 267 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ;
BaserK 0:954f15bd95f1 268 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ;
BaserK 0:954f15bd95f1 269 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ;
BaserK 0:954f15bd95f1 270 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ;
BaserK 0:954f15bd95f1 271 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ;
BaserK 0:954f15bd95f1 272
BaserK 0:954f15bd95f1 273 /* Sum individual signed 16-bit biases to get accumulated signed 32-bit biases */
BaserK 0:954f15bd95f1 274 accel_bias[0] += (int32_t) accel_temp[0];
BaserK 0:954f15bd95f1 275 accel_bias[1] += (int32_t) accel_temp[1];
BaserK 0:954f15bd95f1 276 accel_bias[2] += (int32_t) accel_temp[2];
BaserK 0:954f15bd95f1 277 gyro_bias[0] += (int32_t) gyro_temp[0];
BaserK 0:954f15bd95f1 278 gyro_bias[1] += (int32_t) gyro_temp[1];
BaserK 0:954f15bd95f1 279 gyro_bias[2] += (int32_t) gyro_temp[2];
BaserK 0:954f15bd95f1 280 }
BaserK 0:954f15bd95f1 281
BaserK 0:954f15bd95f1 282 /* Normalize sums to get average count biases */
BaserK 0:954f15bd95f1 283 accel_bias[0] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 284 accel_bias[1] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 285 accel_bias[2] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 286 gyro_bias[0] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 287 gyro_bias[1] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 288 gyro_bias[2] /= (int32_t) packet_count;
BaserK 0:954f15bd95f1 289
BaserK 0:954f15bd95f1 290 /* Remove gravity from the z-axis accelerometer bias calculation */
BaserK 0:954f15bd95f1 291 if(accel_bias[2] > 0) {accel_bias[2] -= (int32_t) accelsensitivity;}
BaserK 0:954f15bd95f1 292 else {accel_bias[2] += (int32_t) accelsensitivity;}
BaserK 0:954f15bd95f1 293
BaserK 0:954f15bd95f1 294 /* Output scaled accelerometer biases for manual subtraction in the main program */
BaserK 0:954f15bd95f1 295 dest1[0] = accel_bias[0]*aRes;
BaserK 0:954f15bd95f1 296 dest1[1] = accel_bias[1]*aRes;
BaserK 0:954f15bd95f1 297 dest1[2] = accel_bias[2]*aRes;
BaserK 0:954f15bd95f1 298
BaserK 0:954f15bd95f1 299 /* Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup */
BaserK 0:954f15bd95f1 300 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 301 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases
BaserK 0:954f15bd95f1 302 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF;
BaserK 0:954f15bd95f1 303 data[3] = (-gyro_bias[1]/4) & 0xFF;
BaserK 0:954f15bd95f1 304 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF;
BaserK 0:954f15bd95f1 305 data[5] = (-gyro_bias[2]/4) & 0xFF;
BaserK 0:954f15bd95f1 306
BaserK 0:954f15bd95f1 307 /* Push gyro biases to hardware registers */
BaserK 0:954f15bd95f1 308 writeByte(MPU6050_ADDRESS, XG_OFFS_USRH, data[0]);
BaserK 0:954f15bd95f1 309 writeByte(MPU6050_ADDRESS, XG_OFFS_USRL, data[1]);
BaserK 0:954f15bd95f1 310 writeByte(MPU6050_ADDRESS, YG_OFFS_USRH, data[2]);
BaserK 0:954f15bd95f1 311 writeByte(MPU6050_ADDRESS, YG_OFFS_USRL, data[3]);
BaserK 0:954f15bd95f1 312 writeByte(MPU6050_ADDRESS, ZG_OFFS_USRH, data[4]);
BaserK 0:954f15bd95f1 313 writeByte(MPU6050_ADDRESS, ZG_OFFS_USRL, data[5]);
BaserK 0:954f15bd95f1 314
BaserK 0:954f15bd95f1 315 /* Construct gyro bias in deg/s for later manual subtraction */
BaserK 0:954f15bd95f1 316 dest2[0] = gyro_bias[0]*gRes;
BaserK 0:954f15bd95f1 317 dest2[1] = gyro_bias[1]*gRes;
BaserK 0:954f15bd95f1 318 dest2[2] = gyro_bias[2]*gRes;
BaserK 0:954f15bd95f1 319 }