Harry Keane
MPU6050 with I2C. NO LCD
Diff: main.cpp
- Revision:
- 0:65aa78c10981
- Child:
- 1:cea9d83b8636
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sun May 25 04:51:50 2014 +0000
@@ -0,0 +1,820 @@
+#include "mbed.h"
+
+/* MPU6050 Basic Example Code
+ by: Kris Winer
+ date: May 1, 2014
+ license: Beerware - Use this code however you'd like. If you
+ find it useful you can buy me a beer some time.
+
+ Demonstrate MPU-6050 basic functionality including initialization, accelerometer trimming, sleep mode functionality as well as
+ parameterizing the register addresses. Added display functions to allow display to on breadboard monitor.
+ No DMP use. We just want to get out the accelerations, temperature, and gyro readings.
+
+ SDA and SCL should have external pull-up resistors (to 3.3V).
+ 10k resistors worked for me. They should be on the breakout
+ board.
+
+ Hardware setup:
+ MPU6050 Breakout --------- Arduino
+ 3.3V --------------------- 3.3V
+ SDA ----------------------- A4
+ SCL ----------------------- A5
+ GND ---------------------- GND
+
+ Note: The MPU6050 is an I2C sensor and uses the Arduino Wire library.
+ Because the sensor is not 5V tolerant, we are using a 3.3 V 8 MHz Pro Mini or a 3.3 V Teensy 3.1.
+ We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file.
+ We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ to 400000L /twi.h utility file.
+ */
+
+//#include <Wire.h>
+//#include <Adafruit_GFX.h>
+//#include <Adafruit_PCD8544.h>
+
+// Using NOKIA 5110 monochrome 84 x 48 pixel display
+// pin 9 - Serial clock out (SCLK)
+// pin 8 - Serial data out (DIN)
+// pin 7 - Data/Command select (D/C)
+// pin 5 - LCD chip select (CS)
+// pin 6 - LCD reset (RST)
+//Adafruit_PCD8544 display = Adafruit_PCD8544(9, 8, 7, 5, 6);
+
+// Define registers per MPU6050, Register Map and Descriptions, Rev 4.2, 08/19/2013 6 DOF Motion sensor fusion device
+// Invensense Inc., www.invensense.com
+// See also MPU-6050 Register Map and Descriptions, Revision 4.0, RM-MPU-6050A-00, 9/12/2012 for registers not listed in
+// above document; the MPU6050 and MPU 9150 are virtually identical but the latter has an on-board magnetic sensor
+//
+#define XGOFFS_TC 0x00 // Bit 7 PWR_MODE, bits 6:1 XG_OFFS_TC, bit 0 OTP_BNK_VLD
+#define YGOFFS_TC 0x01
+#define ZGOFFS_TC 0x02
+#define X_FINE_GAIN 0x03 // [7:0] fine gain
+#define Y_FINE_GAIN 0x04
+#define Z_FINE_GAIN 0x05
+#define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer
+#define XA_OFFSET_L_TC 0x07
+#define YA_OFFSET_H 0x08
+#define YA_OFFSET_L_TC 0x09
+#define ZA_OFFSET_H 0x0A
+#define ZA_OFFSET_L_TC 0x0B
+#define SELF_TEST_X 0x0D
+#define SELF_TEST_Y 0x0E
+#define SELF_TEST_Z 0x0F
+#define SELF_TEST_A 0x10
+#define XG_OFFS_USRH 0x13 // User-defined trim values for gyroscope; supported in MPU-6050?
+#define XG_OFFS_USRL 0x14
+#define YG_OFFS_USRH 0x15
+#define YG_OFFS_USRL 0x16
+#define ZG_OFFS_USRH 0x17
+#define ZG_OFFS_USRL 0x18
+#define SMPLRT_DIV 0x19
+#define CONFIG 0x1A
+#define GYRO_CONFIG 0x1B
+#define ACCEL_CONFIG 0x1C
+#define FF_THR 0x1D // Free-fall
+#define FF_DUR 0x1E // Free-fall
+#define MOT_THR 0x1F // Motion detection threshold bits [7:0]
+#define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms
+#define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0]
+#define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms
+#define FIFO_EN 0x23
+#define I2C_MST_CTRL 0x24
+#define I2C_SLV0_ADDR 0x25
+#define I2C_SLV0_REG 0x26
+#define I2C_SLV0_CTRL 0x27
+#define I2C_SLV1_ADDR 0x28
+#define I2C_SLV1_REG 0x29
+#define I2C_SLV1_CTRL 0x2A
+#define I2C_SLV2_ADDR 0x2B
+#define I2C_SLV2_REG 0x2C
+#define I2C_SLV2_CTRL 0x2D
+#define I2C_SLV3_ADDR 0x2E
+#define I2C_SLV3_REG 0x2F
+#define I2C_SLV3_CTRL 0x30
+#define I2C_SLV4_ADDR 0x31
+#define I2C_SLV4_REG 0x32
+#define I2C_SLV4_DO 0x33
+#define I2C_SLV4_CTRL 0x34
+#define I2C_SLV4_DI 0x35
+#define I2C_MST_STATUS 0x36
+#define INT_PIN_CFG 0x37
+#define INT_ENABLE 0x38
+#define DMP_INT_STATUS 0x39 // Check DMP interrupt
+#define INT_STATUS 0x3A
+#define ACCEL_XOUT_H 0x3B
+#define ACCEL_XOUT_L 0x3C
+#define ACCEL_YOUT_H 0x3D
+#define ACCEL_YOUT_L 0x3E
+#define ACCEL_ZOUT_H 0x3F
+#define ACCEL_ZOUT_L 0x40
+#define TEMP_OUT_H 0x41
+#define TEMP_OUT_L 0x42
+#define GYRO_XOUT_H 0x43
+#define GYRO_XOUT_L 0x44
+#define GYRO_YOUT_H 0x45
+#define GYRO_YOUT_L 0x46
+#define GYRO_ZOUT_H 0x47
+#define GYRO_ZOUT_L 0x48
+#define EXT_SENS_DATA_00 0x49
+#define EXT_SENS_DATA_01 0x4A
+#define EXT_SENS_DATA_02 0x4B
+#define EXT_SENS_DATA_03 0x4C
+#define EXT_SENS_DATA_04 0x4D
+#define EXT_SENS_DATA_05 0x4E
+#define EXT_SENS_DATA_06 0x4F
+#define EXT_SENS_DATA_07 0x50
+#define EXT_SENS_DATA_08 0x51
+#define EXT_SENS_DATA_09 0x52
+#define EXT_SENS_DATA_10 0x53
+#define EXT_SENS_DATA_11 0x54
+#define EXT_SENS_DATA_12 0x55
+#define EXT_SENS_DATA_13 0x56
+#define EXT_SENS_DATA_14 0x57
+#define EXT_SENS_DATA_15 0x58
+#define EXT_SENS_DATA_16 0x59
+#define EXT_SENS_DATA_17 0x5A
+#define EXT_SENS_DATA_18 0x5B
+#define EXT_SENS_DATA_19 0x5C
+#define EXT_SENS_DATA_20 0x5D
+#define EXT_SENS_DATA_21 0x5E
+#define EXT_SENS_DATA_22 0x5F
+#define EXT_SENS_DATA_23 0x60
+#define MOT_DETECT_STATUS 0x61
+#define I2C_SLV0_DO 0x63
+#define I2C_SLV1_DO 0x64
+#define I2C_SLV2_DO 0x65
+#define I2C_SLV3_DO 0x66
+#define I2C_MST_DELAY_CTRL 0x67
+#define SIGNAL_PATH_RESET 0x68
+#define MOT_DETECT_CTRL 0x69
+#define USER_CTRL 0x6A // Bit 7 enable DMP, bit 3 reset DMP
+#define PWR_MGMT_1 0x6B // Device defaults to the SLEEP mode
+#define PWR_MGMT_2 0x6C
+#define DMP_BANK 0x6D // Activates a specific bank in the DMP
+#define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank
+#define DMP_REG 0x6F // Register in DMP from which to read or to which to write
+#define DMP_REG_1 0x70
+#define DMP_REG_2 0x71
+#define FIFO_COUNTH 0x72
+#define FIFO_COUNTL 0x73
+#define FIFO_R_W 0x74
+#define WHO_AM_I_MPU6050 0x75 // Should return 0x68
+
+// Using the GY-521 breakout board, I set ADO to 0 by grounding through a 4k7 resistor
+// Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1
+#define ADO 0
+#if ADO
+#define MPU6050_ADDRESS 0x69 // Device address when ADO = 1
+#else
+#define MPU6050_ADDRESS 0x68 // Device address when ADO = 0
+#endif
+
+// Set up I2C
+I2C i2c(PB_9, PB_8);
+//i2c.frequency(400000); // use fast (400 kHz) I2C
+
+// Set up serial port
+Serial pc(PA_2, PA_3); // PA_2, PA_3 on STM32F01 Nucleo
+
+Timer t;
+
+// Set initial input parameters
+enum Ascale {
+ AFS_2G = 0,
+ AFS_4G,
+ AFS_8G,
+ AFS_16G
+};
+
+enum Gscale {
+ GFS_250DPS = 0,
+ GFS_500DPS,
+ GFS_1000DPS,
+ GFS_2000DPS
+};
+
+// Specify sensor full scale
+int Gscale = GFS_250DPS;
+int Ascale = AFS_2G;
+float aRes, gRes; // scale resolutions per LSB for the sensors
+
+// Pin definitions
+int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins
+char blinkOn = false;
+
+int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output
+float ax, ay, az; // Stores the real accel value in g's
+int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output
+float gx, gy, gz; // Stores the real gyro value in degrees per seconds
+float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer
+int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius
+float temperature;
+float SelfTest[6];
+
+uint32_t delt_t = 0; // used to control display output rate
+uint32_t count = 0; // used to control display output rate
+
+// parameters for 6 DoF sensor fusion calculations
+float PI = 3.141593;
+float GyroMeasError = PI * (60.0f / 180.0f); // gyroscope measurement error in rads/s (start at 60 deg/s), then reduce after ~10 s to 3
+float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta
+float GyroMeasDrift = PI * (0.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s)
+float zeta = sqrt(3.0f / 4.0f) * GyroMeasDrift; // compute zeta, the other free parameter in the Madgwick scheme usually set to a small or zero value
+float pitch, yaw, roll;
+float deltat = 0.0f; // integration interval for both filter schemes
+uint32_t lastUpdate = 0, firstUpdate = 0; // used to calculate integration interval
+uint32_t Now = 0; // used to calculate integration interval
+float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion
+
+DigitalOut myled(LED1);
+
+//===================================================================================================================
+//====== Set of useful function to access acceleratio, gyroscope, and temperature data
+//===================================================================================================================
+
+ void writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
+{
+ i2c.write(address);
+ i2c.write(subAddress);
+ i2c.write(data);
+}
+
+ uint8_t readByte(uint8_t address, uint8_t subAddress)
+{
+ uint8_t data; // `data` will store the register data
+ i2c.write(address);
+ i2c.write(subAddress);
+ data = i2c.read(1); // read the length byte and the 7 databytes
+ return data; // Return data read from slave register
+}
+
+ void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest)
+{
+ i2c.write(address);
+ i2c.write(subAddress);
+ for (int ii = 0; ii < count; ii++) {
+ dest[ii] = i2c.read(1);
+ }
+
+}
+void getGres() {
+ switch (Gscale)
+ {
+ // Possible gyro scales (and their register bit settings) are:
+ // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11).
+ // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value:
+ case GFS_250DPS:
+ gRes = 250.0/32768.0;
+ break;
+ case GFS_500DPS:
+ gRes = 500.0/32768.0;
+ break;
+ case GFS_1000DPS:
+ gRes = 1000.0/32768.0;
+ break;
+ case GFS_2000DPS:
+ gRes = 2000.0/32768.0;
+ break;
+ }
+}
+
+void getAres() {
+ switch (Ascale)
+ {
+ // Possible accelerometer scales (and their register bit settings) are:
+ // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11).
+ // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value:
+ case AFS_2G:
+ aRes = 2.0/32768.0;
+ break;
+ case AFS_4G:
+ aRes = 4.0/32768.0;
+ break;
+ case AFS_8G:
+ aRes = 8.0/32768.0;
+ break;
+ case AFS_16G:
+ aRes = 16.0/32768.0;
+ break;
+ }
+}
+
+
+void readAccelData(int16_t * destination)
+{
+ uint8_t rawData[6]; // x/y/z accel register data stored here
+ readBytes(MPU6050_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array
+ destination[0] = (int16_t)((rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
+ destination[1] = (int16_t)((rawData[2] << 8) | rawData[3]) ;
+ destination[2] = (int16_t)((rawData[4] << 8) | rawData[5]) ;
+}
+
+void readGyroData(int16_t * destination)
+{
+ uint8_t rawData[6]; // x/y/z gyro register data stored here
+ readBytes(MPU6050_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array
+ destination[0] = (int16_t)((rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
+ destination[1] = (int16_t)((rawData[2] << 8) | rawData[3]) ;
+ destination[2] = (int16_t)((rawData[4] << 8) | rawData[5]) ;
+}
+
+int16_t readTempData()
+{
+ uint8_t rawData[2]; // x/y/z gyro register data stored here
+ readBytes(MPU6050_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array
+ return ((int16_t)rawData[0]) << 8 | rawData[1] ; // Turn the MSB and LSB into a 16-bit value
+}
+
+
+
+// Configure the motion detection control for low power accelerometer mode
+void LowPowerAccelOnlyMPU6050()
+{
+
+// The sensor has a high-pass filter necessary to invoke to allow the sensor motion detection algorithms work properly
+// Motion detection occurs on free-fall (acceleration below a threshold for some time for all axes), motion (acceleration
+// above a threshold for some time on at least one axis), and zero-motion toggle (acceleration on each axis less than a
+// threshold for some time sets this flag, motion above the threshold turns it off). The high-pass filter takes gravity out
+// consideration for these threshold evaluations; otherwise, the flags would be set all the time!
+
+ uint8_t c = readByte(MPU6050_ADDRESS, PWR_MGMT_1);
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c & ~0x30); // Clear sleep and cycle bits [5:6]
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c | 0x30); // Set sleep and cycle bits [5:6] to zero to make sure accelerometer is running
+
+ c = readByte(MPU6050_ADDRESS, PWR_MGMT_2);
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c & ~0x38); // Clear standby XA, YA, and ZA bits [3:5]
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c | 0x00); // Set XA, YA, and ZA bits [3:5] to zero to make sure accelerometer is running
+
+ c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x07); // Clear high-pass filter bits [2:0]
+// Set high-pass filter to 0) reset (disable), 1) 5 Hz, 2) 2.5 Hz, 3) 1.25 Hz, 4) 0.63 Hz, or 7) Hold
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | 0x00); // Set ACCEL_HPF to 0; reset mode disbaling high-pass filter
+
+ c = readByte(MPU6050_ADDRESS, CONFIG);
+ writeByte(MPU6050_ADDRESS, CONFIG, c & ~0x07); // Clear low-pass filter bits [2:0]
+ writeByte(MPU6050_ADDRESS, CONFIG, c | 0x00); // Set DLPD_CFG to 0; 260 Hz bandwidth, 1 kHz rate
+
+ c = readByte(MPU6050_ADDRESS, INT_ENABLE);
+ writeByte(MPU6050_ADDRESS, INT_ENABLE, c & ~0xFF); // Clear all interrupts
+ writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x40); // Enable motion threshold (bits 5) interrupt only
+
+// Motion detection interrupt requires the absolute value of any axis to lie above the detection threshold
+// for at least the counter duration
+ writeByte(MPU6050_ADDRESS, MOT_THR, 0x80); // Set motion detection to 0.256 g; LSB = 2 mg
+ writeByte(MPU6050_ADDRESS, MOT_DUR, 0x01); // Set motion detect duration to 1 ms; LSB is 1 ms @ 1 kHz rate
+
+ wait(0.1); // Add delay for accumulation of samples
+
+ c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x07); // Clear high-pass filter bits [2:0]
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | 0x07); // Set ACCEL_HPF to 7; hold the initial accleration value as a referance
+
+ c = readByte(MPU6050_ADDRESS, PWR_MGMT_2);
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c & ~0xC7); // Clear standby XA, YA, and ZA bits [3:5] and LP_WAKE_CTRL bits [6:7]
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c | 0x47); // Set wakeup frequency to 5 Hz, and disable XG, YG, and ZG gyros (bits [0:2])
+
+ c = readByte(MPU6050_ADDRESS, PWR_MGMT_1);
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c & ~0x20); // Clear sleep and cycle bit 5
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c | 0x20); // Set cycle bit 5 to begin low power accelerometer motion interrupts
+
+}
+
+
+void initMPU6050()
+{
+ // Initialize MPU6050 device
+ // reset device
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
+ wait(0.1);
+
+ // wake up device
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors
+ wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt
+
+ // get stable time source
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
+
+ // Configure Gyro and Accelerometer
+ // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively;
+ // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both
+ // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate
+ writeByte(MPU6050_ADDRESS, CONFIG, 0x03);
+
+ // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV)
+ writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above
+
+ // Set gyroscope full scale range
+ // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3
+ uint8_t c = readByte(MPU6050_ADDRESS, GYRO_CONFIG);
+ writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
+ writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
+ writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro
+
+ // Set accelerometer configuration
+ c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer
+
+ // Configure Interrupts and Bypass Enable
+ // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips
+ // can join the I2C bus and all can be controlled by the Arduino as master
+ writeByte(MPU6050_ADDRESS, INT_PIN_CFG, 0x22);
+ writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt
+}
+
+// Function which accumulates gyro and accelerometer data after device initialization. It calculates the average
+// of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers.
+void calibrateMPU6050(float * dest1, float * dest2)
+{
+ uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data
+ uint8_t ii, fifo_count, packet_count;
+ int16_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0};
+
+// reset device, reset all registers, clear gyro and accelerometer bias registers
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
+ wait(0.1);
+
+// get stable time source
+// Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01);
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_2, 0x00);
+ wait(0.2);
+
+// Configure device for bias calculation
+ writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts
+ writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
+ writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source
+ writeByte(MPU6050_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master
+ writeByte(MPU6050_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes
+ writeByte(MPU6050_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP
+ wait(0.015);
+
+// Configure MPU6050 gyro and accelerometer for bias calculation
+ writeByte(MPU6050_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz
+ writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz
+ writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity
+ wait(0.2);
+
+ uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec
+ uint16_t accelsensitivity = 16384; // = 16384 LSB/g
+
+// Configure FIFO to capture accelerometer and gyro data for bias calculation
+ writeByte(MPU6050_ADDRESS, USER_CTRL, 0x40); // Enable FIFO
+ writeByte(MPU6050_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 1024 bytes in MPU-6050)
+ wait(0.08); // accumulate 80 samples in 80 milliseconds = 960 bytes
+
+// At end of sample accumulation, turn off FIFO sensor read
+ writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO
+ readBytes(MPU6050_ADDRESS, FIFO_COUNTH, 2, data); // read FIFO sample count
+ fifo_count = ((uint16_t)data[0] << 8) | data[1];
+ packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging
+
+ for (ii = 0; ii < packet_count; ii++) {
+ readBytes(MPU6050_ADDRESS, FIFO_R_W, 12, data); // read data for averaging
+ accel_bias[0] += (((int16_t)data[0] << 8) | data[1] ) ; // Divide sum of FIFO gyro data by number of samples
+ accel_bias[1] += (((int16_t)data[2] << 8) | data[3] ) ;
+ accel_bias[2] += (((int16_t)data[4] << 8) | data[5] ) - accelsensitivity; // Assumes device facing up!
+ gyro_bias[0] += (((int16_t)data[6] << 8) | data[7] ) ;
+ gyro_bias[1] += (((int16_t)data[8] << 8) | data[9] ) ;
+ gyro_bias[2] += (((int16_t)data[10] << 8) | data[11]) ;
+}
+
+ accel_bias[0] /= packet_count; // Normalize sums to get average count biases
+ accel_bias[1] /= packet_count;
+ accel_bias[2] /= packet_count;
+ gyro_bias[0] /= packet_count;
+ gyro_bias[1] /= packet_count;
+ gyro_bias[2] /= packet_count;
+
+// Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup
+ 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
+ data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases
+ data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF;
+ data[3] = (-gyro_bias[1]/4) & 0xFF;
+ data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF;
+ data[5] = (-gyro_bias[2]/4) & 0xFF;
+
+// Push gyro biases to hardware registers
+// writeByte(MPU6050_ADDRESS, XG_OFFS_USRH, data[0]); // might not be supported in MPU6050
+// writeByte(MPU6050_ADDRESS, XG_OFFS_USRL, data[1]);
+// writeByte(MPU6050_ADDRESS, YG_OFFS_USRH, data[2]);
+// writeByte(MPU6050_ADDRESS, YG_OFFS_USRL, data[3]);
+// writeByte(MPU6050_ADDRESS, ZG_OFFS_USRH, data[4]);
+// writeByte(MPU6050_ADDRESS, ZG_OFFS_USRL, data[5]);
+
+ dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
+ dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
+ dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;
+
+// Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain
+// factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold
+// non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature
+// compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that
+// the accelerometer biases calculated above must be divided by 8.
+
+ int16_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases
+ readBytes(MPU6050_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values
+ accel_bias_reg[0] = ((int16_t)data[0] << 8) | data[1];
+ readBytes(MPU6050_ADDRESS, YA_OFFSET_H, 2, &data[0]);
+ accel_bias_reg[1] = ((int16_t)data[0] << 8) | data[1];
+ readBytes(MPU6050_ADDRESS, ZA_OFFSET_H, 2, &data[0]);
+ accel_bias_reg[2] = ((int16_t)data[0] << 8) | data[1];
+
+ int16_t mask = 0x0001; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers
+ uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis
+
+ for(ii = 0; ii < 3; ii++) {
+ if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit
+ }
+
+ // Construct total accelerometer bias, including calculated average accelerometer bias from above
+ accel_bias_reg[0] -= accel_bias[0]/8; // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale)
+ accel_bias_reg[1] -= accel_bias[1]/8;
+ accel_bias_reg[2] -= accel_bias[2]/8;
+
+ data[0] = (accel_bias_reg[0] >> 8) & 0xFF;
+ data[1] = (accel_bias_reg[0]) & 0xFF;
+ data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers
+ data[2] = (accel_bias_reg[1] >> 8) & 0xFF;
+ data[3] = (accel_bias_reg[1]) & 0xFF;
+ data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers
+ data[4] = (accel_bias_reg[2] >> 8) & 0xFF;
+ data[5] = (accel_bias_reg[2]) & 0xFF;
+ data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers
+
+ // Push accelerometer biases to hardware registers
+// writeByte(MPU6050_ADDRESS, XA_OFFSET_H, data[0]); // might not be supported in MPU6050
+// writeByte(MPU6050_ADDRESS, XA_OFFSET_L_TC, data[1]);
+// writeByte(MPU6050_ADDRESS, YA_OFFSET_H, data[2]);
+// writeByte(MPU6050_ADDRESS, YA_OFFSET_L_TC, data[3]);
+// writeByte(MPU6050_ADDRESS, ZA_OFFSET_H, data[4]);
+// writeByte(MPU6050_ADDRESS, ZA_OFFSET_L_TC, data[5]);
+
+// Output scaled accelerometer biases for manual subtraction in the main program
+ dest2[0] = (float)accel_bias[0]/(float)accelsensitivity;
+ dest2[1] = (float)accel_bias[1]/(float)accelsensitivity;
+ dest2[2] = (float)accel_bias[2]/(float)accelsensitivity;
+ }
+
+
+// Accelerometer and gyroscope self test; check calibration wrt factory settings
+void MPU6050SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass
+{
+ uint8_t rawData[4];
+ uint8_t selfTest[6];
+ float factoryTrim[6];
+
+ // Configure the accelerometer for self-test
+ writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0xF0); // Enable self test on all three axes and set accelerometer range to +/- 8 g
+ writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s
+ wait(0.25); // Delay a while to let the device execute the self-test
+ rawData[0] = readByte(MPU6050_ADDRESS, SELF_TEST_X); // X-axis self-test results
+ rawData[1] = readByte(MPU6050_ADDRESS, SELF_TEST_Y); // Y-axis self-test results
+ rawData[2] = readByte(MPU6050_ADDRESS, SELF_TEST_Z); // Z-axis self-test results
+ rawData[3] = readByte(MPU6050_ADDRESS, SELF_TEST_A); // Mixed-axis self-test results
+ // Extract the acceleration test results first
+ selfTest[0] = (rawData[0] >> 3) | (rawData[3] & 0x30) >> 4 ; // XA_TEST result is a five-bit unsigned integer
+ selfTest[1] = (rawData[1] >> 3) | (rawData[3] & 0x0C) >> 4 ; // YA_TEST result is a five-bit unsigned integer
+ selfTest[2] = (rawData[2] >> 3) | (rawData[3] & 0x03) >> 4 ; // ZA_TEST result is a five-bit unsigned integer
+ // Extract the gyration test results first
+ selfTest[3] = rawData[0] & 0x1F ; // XG_TEST result is a five-bit unsigned integer
+ selfTest[4] = rawData[1] & 0x1F ; // YG_TEST result is a five-bit unsigned integer
+ selfTest[5] = rawData[2] & 0x1F ; // ZG_TEST result is a five-bit unsigned integer
+ // Process results to allow final comparison with factory set values
+ factoryTrim[0] = (4096.0*0.34)*(pow( (0.92/0.34) , ((selfTest[0] - 1.0)/30.0))); // FT[Xa] factory trim calculation
+ factoryTrim[1] = (4096.0*0.34)*(pow( (0.92/0.34) , ((selfTest[1] - 1.0)/30.0))); // FT[Ya] factory trim calculation
+ factoryTrim[2] = (4096.0*0.34)*(pow( (0.92/0.34) , ((selfTest[2] - 1.0)/30.0))); // FT[Za] factory trim calculation
+ factoryTrim[3] = ( 25.0*131.0)*(pow( 1.046 , (selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation
+ factoryTrim[4] = (-25.0*131.0)*(pow( 1.046 , (selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation
+ factoryTrim[5] = ( 25.0*131.0)*(pow( 1.046 , (selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation
+
+ // Output self-test results and factory trim calculation if desired
+ // Serial.println(selfTest[0]); Serial.println(selfTest[1]); Serial.println(selfTest[2]);
+ // Serial.println(selfTest[3]); Serial.println(selfTest[4]); Serial.println(selfTest[5]);
+ // Serial.println(factoryTrim[0]); Serial.println(factoryTrim[1]); Serial.println(factoryTrim[2]);
+ // Serial.println(factoryTrim[3]); Serial.println(factoryTrim[4]); Serial.println(factoryTrim[5]);
+
+ // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response
+ // To get to percent, must multiply by 100 and subtract result from 100
+ for (int i = 0; i < 6; i++) {
+ destination[i] = 100.0 + 100.0*(selfTest[i] - factoryTrim[i])/factoryTrim[i]; // Report percent differences
+ }
+
+}
+
+
+// Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays"
+// (see http://www.x-io.co.uk/category/open-source/ for examples and more details)
+// which fuses acceleration and rotation rate to produce a quaternion-based estimate of relative
+// device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc.
+// The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms
+// but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz!
+ void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz)
+ {
+ float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
+ float norm; // vector norm
+ float f1, f2, f3; // objetive funcyion elements
+ float J_11or24, J_12or23, J_13or22, J_14or21, J_32, J_33; // objective function Jacobian elements
+ float qDot1, qDot2, qDot3, qDot4;
+ float hatDot1, hatDot2, hatDot3, hatDot4;
+ float gerrx, gerry, gerrz, gbiasx, gbiasy, gbiasz; // gyro bias error
+
+ // Auxiliary variables to avoid repeated arithmetic
+ float _halfq1 = 0.5f * q1;
+ float _halfq2 = 0.5f * q2;
+ float _halfq3 = 0.5f * q3;
+ float _halfq4 = 0.5f * q4;
+ float _2q1 = 2.0f * q1;
+ float _2q2 = 2.0f * q2;
+ float _2q3 = 2.0f * q3;
+ float _2q4 = 2.0f * q4;
+// float _2q1q3 = 2.0f * q1 * q3;
+// float _2q3q4 = 2.0f * q3 * q4;
+
+ // Normalise accelerometer measurement
+ norm = sqrt(ax * ax + ay * ay + az * az);
+ if (norm == 0.0f) return; // handle NaN
+ norm = 1.0f/norm;
+ ax *= norm;
+ ay *= norm;
+ az *= norm;
+
+ // Compute the objective function and Jacobian
+ f1 = _2q2 * q4 - _2q1 * q3 - ax;
+ f2 = _2q1 * q2 + _2q3 * q4 - ay;
+ f3 = 1.0f - _2q2 * q2 - _2q3 * q3 - az;
+ J_11or24 = _2q3;
+ J_12or23 = _2q4;
+ J_13or22 = _2q1;
+ J_14or21 = _2q2;
+ J_32 = 2.0f * J_14or21;
+ J_33 = 2.0f * J_11or24;
+
+ // Compute the gradient (matrix multiplication)
+ hatDot1 = J_14or21 * f2 - J_11or24 * f1;
+ hatDot2 = J_12or23 * f1 + J_13or22 * f2 - J_32 * f3;
+ hatDot3 = J_12or23 * f2 - J_33 *f3 - J_13or22 * f1;
+ hatDot4 = J_14or21 * f1 + J_11or24 * f2;
+
+ // Normalize the gradient
+ norm = sqrt(hatDot1 * hatDot1 + hatDot2 * hatDot2 + hatDot3 * hatDot3 + hatDot4 * hatDot4);
+ hatDot1 /= norm;
+ hatDot2 /= norm;
+ hatDot3 /= norm;
+ hatDot4 /= norm;
+
+ // Compute estimated gyroscope biases
+ gerrx = _2q1 * hatDot2 - _2q2 * hatDot1 - _2q3 * hatDot4 + _2q4 * hatDot3;
+ gerry = _2q1 * hatDot3 + _2q2 * hatDot4 - _2q3 * hatDot1 - _2q4 * hatDot2;
+ gerrz = _2q1 * hatDot4 - _2q2 * hatDot3 + _2q3 * hatDot2 - _2q4 * hatDot1;
+
+ // Compute and remove gyroscope biases
+ gbiasx += gerrx * deltat * zeta;
+ gbiasy += gerry * deltat * zeta;
+ gbiasz += gerrz * deltat * zeta;
+ gx -= gbiasx;
+ gy -= gbiasy;
+ gz -= gbiasz;
+
+ // Compute the quaternion derivative
+ qDot1 = -_halfq2 * gx - _halfq3 * gy - _halfq4 * gz;
+ qDot2 = _halfq1 * gx + _halfq3 * gz - _halfq4 * gy;
+ qDot3 = _halfq1 * gy - _halfq2 * gz + _halfq4 * gx;
+ qDot4 = _halfq1 * gz + _halfq2 * gy - _halfq3 * gx;
+
+ // Compute then integrate estimated quaternion derivative
+ q1 += (qDot1 -(beta * hatDot1)) * deltat;
+ q2 += (qDot2 -(beta * hatDot2)) * deltat;
+ q3 += (qDot3 -(beta * hatDot3)) * deltat;
+ q4 += (qDot4 -(beta * hatDot4)) * deltat;
+
+ // Normalize the quaternion
+ norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion
+ norm = 1.0f/norm;
+ q[0] = q1 * norm;
+ q[1] = q2 * norm;
+ q[2] = q3 * norm;
+ q[3] = q4 * norm;
+ }
+
+
+void setup()
+{
+
+ // Read the WHO_AM_I register, this is a good test of communication
+ uint8_t c = readByte(MPU6050_ADDRESS, WHO_AM_I_MPU6050); // Read WHO_AM_I register for MPU-6050
+
+ if (c == 0x68) // WHO_AM_I should always be 0x68
+ {
+ pc.printf("MPU6050 is online...");
+
+ MPU6050SelfTest(SelfTest); // Start by performing self test and reporting values
+ pc.printf("x-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[0]); pc.printf("% of factory value");
+ pc.printf("y-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[1]); pc.printf("% of factory value");
+ pc.printf("z-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[2]); pc.printf("% of factory value");
+ pc.printf("x-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[3]); pc.printf("% of factory value");
+ pc.printf("y-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[4]); pc.printf("% of factory value");
+ pc.printf("z-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[5]); pc.printf("% of factory value");
+
+ if(SelfTest[0] < 1.0f && SelfTest[1] < 1.0f && SelfTest[2] < 1.0f && SelfTest[3] < 1.0f && SelfTest[4] < 1.0f && SelfTest[5] < 1.0f) {
+
+ calibrateMPU6050(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers
+ initMPU6050(); pc.printf("MPU6050 initialized for active data mode...."); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
+ }
+ else
+ {
+ pc.printf("Could not connect to MPU6050: 0x");
+ pc.printf("%h", c);
+ while(1) ; // Loop forever if communication doesn't happen
+ }
+}
+}
+
+
+int main()
+{
+ // If data ready bit set, all data registers have new data
+ if(readByte(MPU6050_ADDRESS, INT_STATUS) & 0x01) { // check if data ready interrupt
+ readAccelData(accelCount); // Read the x/y/z adc values
+ getAres();
+
+ // Now we'll calculate the accleration value into actual g's
+ ax = (float)accelCount[0]*aRes - accelBias[0]; // get actual g value, this depends on scale being set
+ ay = (float)accelCount[1]*aRes - accelBias[1];
+ az = (float)accelCount[2]*aRes - accelBias[2];
+
+ readGyroData(gyroCount); // Read the x/y/z adc values
+ getGres();
+
+ // Calculate the gyro value into actual degrees per second
+ gx = (float)gyroCount[0]*gRes - gyroBias[0]; // get actual gyro value, this depends on scale being set
+ gy = (float)gyroCount[1]*gRes - gyroBias[1];
+ gz = (float)gyroCount[2]*gRes - gyroBias[2];
+
+ tempCount = readTempData(); // Read the x/y/z adc values
+ temperature = (tempCount) / 340. + 36.53; // Temperature in degrees Centigrade
+ }
+
+ Now = t.read_us();
+ deltat = ((Now - lastUpdate)/1000000.0f); // set integration time by time elapsed since last filter update
+ lastUpdate = Now;
+ if(lastUpdate - firstUpdate > 10000000.0f) {
+ beta = 0.04; // decrease filter gain after stabilized
+ zeta = 0.015; // increaseyro bias drift gain after stabilized
+ }
+ // Pass gyro rate as rad/s
+ MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f);
+
+ // Serial print and/or display at 0.5 s rate independent of data rates
+ delt_t = t.read_ms() - count;
+ if (delt_t > 500) { // update LCD once per half-second independent of read rate
+ // DigitalOut(LED1);
+
+ pc.printf("ax = "); pc.printf("%i", 1000*ax);
+ pc.printf(" ay = "); pc.printf("%i", 1000*ay);
+ pc.printf(" az = "); pc.printf("%i", 1000*az); pc.printf(" mg");
+
+ pc.printf("gx = "); pc.printf("%f", gx);
+ pc.printf(" gy = "); pc.printf("%f", gy);
+ pc.printf(" gz = "); pc.printf("%f", gz); pc.printf(" deg/s");
+
+ pc.printf("q0 = "); pc.printf("%f", q[0]);
+ pc.printf(" qx = "); pc.printf("%f", q[1]);
+ pc.printf(" qy = "); pc.printf("%f", q[2]);
+ pc.printf(" qz = "); pc.printf("%f", q[3]);
+
+ // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
+ // In this coordinate system, the positive z-axis is down toward Earth.
+ // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise.
+ // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
+ // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
+ // These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
+ // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be
+ // applied in the correct order which for this configuration is yaw, pitch, and then roll.
+ // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links.
+ yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);
+ pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
+ roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]);
+ pitch *= 180.0f / PI;
+ yaw *= 180.0f / PI;
+ roll *= 180.0f / PI;
+
+ pc.printf("Yaw, Pitch, Roll: ");
+ pc.printf("%f", yaw);
+ pc.printf(", ");
+ pc.printf("%f", pitch);
+ pc.printf(", ");
+ pc.printf("%f", roll);
+
+ pc.printf("average rate = "); pc.printf("%f", (1.0f/deltat)); pc.printf(" Hz");
+
+
+ blinkOn = ~blinkOn;
+ count = t.read_ms();
+}
+ while(1) {
+ myled = !myled;
+ wait(1);
+ }
+}