// Alternative names for the combined definitions
// The names uses the Wake-up Frequency.
#define MPU6050_LP_WAKE_1_25HZ MPU6050_LP_WAKE_CTRL_0
#define MPU6050_LP_WAKE_2_5HZ MPU6050_LP_WAKE_CTRL_1
#define MPU6050_LP_WAKE_5HZ MPU6050_LP_WAKE_CTRL_2
#define MPU6050_LP_WAKE_10HZ MPU6050_LP_WAKE_CTRL_3
// Default I2C address for the MPU-6050 is 0x68.
// But only if the AD0 pin is low.
// Some sensor boards have AD0 high, and the
// I2C address thus becomes 0x69.
#define MPU6050_I2C_ADDRESS 0x68
// Declaring an union for the registers and the axis values.
// The byte order does not match the byte order of
// the compiler and AVR chip.
// The AVR chip (on the Arduino board) has the Low Byte
// at the lower address.
// But the MPU-6050 has a different order: High Byte at
// lower address, so that has to be corrected.
// The register part "reg" is only used internally,
// and are swapped in code.
typedef union accel_t_gyro_union
{
struct
{
uint8_t x_accel_h;
uint8_t x_accel_l;
uint8_t y_accel_h;
uint8_t y_accel_l;
uint8_t z_accel_h;
uint8_t z_accel_l;
uint8_t t_h;
uint8_t t_l;
uint8_t x_gyro_h;
uint8_t x_gyro_l;
uint8_t y_gyro_h;
uint8_t y_gyro_l;
uint8_t z_gyro_h;
uint8_t z_gyro_l;
} reg;
struct
{
int16_t x_accel;
int16_t y_accel;
int16_t z_accel;
int16_t temperature;
int16_t x_gyro;
int16_t y_gyro;
int16_t z_gyro;
} value;
};
void setup()
{
int error;
uint8_t c;
Serial.begin(9600);
Serial.println(F("InvenSense MPU-6050"));
Serial.println(F("June 2012"));
// Initialize the 'Wire' class for the I2C-bus.
Wire.begin();
// default at power-up:
// Gyro at 250 degrees second
// Acceleration at 2g
// Clock source at internal 8MHz
// The device is in sleep mode.
//
error = MPU6050_read (MPU6050_WHO_AM_I, &c, 1);
Serial.print(F("WHO_AM_I : "));
Serial.print(c,HEX);
Serial.print(F(", error = "));
Serial.println(error,DEC);
// According to the datasheet, the 'sleep' bit
// should read a '1'. But I read a '0'.
// That bit has to be cleared, since the sensor
// is in sleep mode at power-up. Even if the
// bit reads '0'.
error = MPU6050_read (MPU6050_PWR_MGMT_2, &c, 1);
Serial.print(F("PWR_MGMT_2 : "));
Serial.print(c,HEX);
Serial.print(F(", error = "));
Serial.println(error,DEC);
// Clear the 'sleep' bit to start the sensor.
MPU6050_write_reg (MPU6050_PWR_MGMT_1, 0);
}
void loop()
{
int error;
double dT;
accel_t_gyro_union accel_t_gyro;
Serial.println(F(""));
Serial.println(F("MPU-6050"));
// Read the raw values.
// Read 14 bytes at once,
// containing acceleration, temperature and gyro.
// With the default settings of the MPU-6050,
// there is no filter enabled, and the values
// are not very stable.
error = MPU6050_read (MPU6050_ACCEL_XOUT_H, (uint8_t *) &accel_t_gyro, sizeof(accel_t_gyro));
Serial.print(F("Read accel, temp and gyro, error = "));
Serial.println(error,DEC);
// Swap all high and low bytes.
// After this, the registers values are swapped,
// so the structure name like x_accel_l does no
// longer contain the lower byte.
uint8_t swap;
#define SWAP(x,y) swap = x; x = y; y = swap
SWAP (accel_t_gyro.reg.x_accel_h, accel_t_gyro.reg.x_accel_l);
SWAP (accel_t_gyro.reg.y_accel_h, accel_t_gyro.reg.y_accel_l);
SWAP (accel_t_gyro.reg.z_accel_h, accel_t_gyro.reg.z_accel_l);
SWAP (accel_t_gyro.reg.t_h, accel_t_gyro.reg.t_l);
SWAP (accel_t_gyro.reg.x_gyro_h, accel_t_gyro.reg.x_gyro_l);
SWAP (accel_t_gyro.reg.y_gyro_h, accel_t_gyro.reg.y_gyro_l);
SWAP (accel_t_gyro.reg.z_gyro_h, accel_t_gyro.reg.z_gyro_l);
// Print the raw acceleration values
Serial.print(F("accel x,y,z: "));
Serial.print(accel_t_gyro.value.x_accel, DEC);
Serial.print(F(", "));
Serial.print(accel_t_gyro.value.y_accel, DEC);
Serial.print(F(", "));
Serial.print(accel_t_gyro.value.z_accel, DEC);
Serial.println(F(""));
// The temperature sensor is -40 to +85 degrees Celsius.
// It is a signed integer.
// According to the datasheet:
// 340 per degrees Celsius, -512 at 35 degrees.
// At 0 degrees: -512 - (340 * 35) = -12412
Serial.print(F("temperature: "));
dT = ( (double) accel_t_gyro.value.temperature + 12412.0) / 340.0;
Serial.print(dT, 3);
Serial.print(F(" degrees Celsius"));
Serial.println(F(""));
// Print the raw gyro values.
Serial.print(F("gyro x,y,z : "));
Serial.print(accel_t_gyro.value.x_gyro, DEC);
Serial.print(F(", "));
Serial.print(accel_t_gyro.value.y_gyro, DEC);
Serial.print(F(", "));
Serial.print(accel_t_gyro.value.z_gyro, DEC);
Serial.print(F(", "));
Serial.println(F(""));
delay(1000);
}
// --------------------------------------------------------
// MPU6050_read
//
// This is a common function to read multiple bytes
// from an I2C device.
//
// It uses the boolean parameter for Wire.endTransMission()
// to be able to hold or release the I2C-bus.
// This is implemented in Arduino 1.0.1.
//
// Only this function is used to read.
// There is no function for a single byte.
//
int MPU6050_read(int start, uint8_t *buffer, int size)
{
int i, n, error;
Wire.beginTransmission(MPU6050_I2C_ADDRESS);
n = Wire.write(start);
if (n != 1)
return (-10);
n = Wire.endTransmission(false); // hold the I2C-bus
if (n != 0)
return (n);
// Third parameter is true: relase I2C-bus after data is read.
Wire.requestFrom(MPU6050_I2C_ADDRESS, size, true);
i = 0;
while(Wire.available() && i<size)
{
buffer[i++]=Wire.read();
}
if ( i != size)
return (-11);
return (0); // return : no error
}
// --------------------------------------------------------
// MPU6050_write
//
// This is a common function to write multiple bytes to an I2C device.
//
// If only a single register is written,
// use the function MPU_6050_write_reg().
//
// Parameters:
// start : Start address, use a define for the register
// pData : A pointer to the data to write.
// size : The number of bytes to write.
//
// If only a single register is written, a pointer
// to the data has to be used, and the size is
// a single byte:
// int data = 0; // the data to write
// MPU6050_write (MPU6050_PWR_MGMT_1, &c, 1);
//
int MPU6050_write(int start, const uint8_t *pData, int size)
{
int n, error;
Wire.beginTransmission(MPU6050_I2C_ADDRESS);
n = Wire.write(start); // write the start address
if (n != 1)
return (-20);
n = Wire.write(pData, size); // write data bytes
if (n != size)
return (-21);
error = Wire.endTransmission(true); // release the I2C-bus
if (error != 0)
return (error);
return (0); // return : no error
}
// --------------------------------------------------------
// MPU6050_write_reg
//
// An extra function to write a single register.
// It is just a wrapper around the MPU_6050_write()
// function, and it is only a convenient function
// to make it easier to write a single register.
//
int MPU6050_write_reg(int reg, uint8_t data)
{
int error;
error = MPU6050_write(reg, &data, 1);
return (error);
}