James Watanabe / ITG3200

Forked from Aaron Berk's ITG3200 driver class library, customized for my specific application using 9DoF-Stick by Sparkfun.

Dependents:   HARP

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ITG3200 Class Reference
Public Types | Public Member Functions | Static Public Attributes | Protected Member Functions | Protected Attributes

ITG3200 Class Reference

ITG-3200 triple axis digital gyroscope. More...

#include <ITG3200.h>

Public Types

enum  Correction { NoCorrection, OffsetCorrection, Calibration }
 

Zero offset correction mode that can be specified when calling getGyroXYZ().

More...

Public Member Functions

 ITG3200 (PinName sda, PinName scl, bool fastmode=false)
 Constructor.
 ITG3200 (I2C &i2c)
 Constructor that accepts external i2c interface object.
void setCalibrationCurve (const float offset[3], const float slope[3])
 Sets calibration curve parameters.
char getWhoAmI (void)
 Get the identity of the device.
void setWhoAmI (char address)
 Set the address of the device.
char getSampleRateDivider (void)
 Get the sample rate divider.
void setSampleRateDivider (char divider)
 Set the sample rate divider.
int getInternalSampleRate (void)
 Get the internal sample rate.
void setLpBandwidth (char bandwidth)
 Set the low pass filter bandwidth.
char getInterruptConfiguration (void)
 Get the interrupt configuration.
void setInterruptConfiguration (char config)
 Set the interrupt configuration.
bool isPllReady (void)
 Check the ITG_RDY bit of the INT_STATUS register.
bool isRawDataReady (void)
 Check the RAW_DATA_RDY bit of the INT_STATUS register.
int getRawTemperature (void)
 Get the temperature in raw format.
float getTemperature (void)
 Get the temperature of the device.
int getGyroX (void)
 Get the output for the x-axis gyroscope.
int getGyroY (void)
 Get the output for the y-axis gyroscope.
int getGyroZ (void)
 Get the output on the z-axis gyroscope.
void getGyroXYZ (int readings[3], Correction corr=OffsetCorrection)
 Burst read the outputs on the x,y,z-axis gyroscope.
void getGyroXYZDegrees (double readings[3], Correction corr=OffsetCorrection)
 Burst read the outputs on the x,y,z-axis gyroscope and convert them into degrees per second.
void getGyroXYZRadians (double readings[3], Correction corr=OffsetCorrection)
 Burst read the outputs on the x,y,z-axis gyroscope and convert them into degrees per second.
char getPowerManagement (void)
 Get the power management configuration.
void setPowerManagement (char config)
 Set power management configuration.
void calibrate (double time)
 Calibrate the sensor drift by sampling zero offset.
I2C & getI2C ()
 Returns the I2C object that this object is using for communication.
const int * getOffset () const
 Returns internal offset values for zero adjusting.

Static Public Attributes

static const int I2C_ADDRESS = 0xD0
 The I2C address that can be passed directly to i2c object (it's already shifted 1 bit left).

Protected Member Functions

int getWord (int regi)
 Reads a word (2 bytes) from the sensor via I2C bus.
void getRawGyroXYZ (int readings[3])
 An internal method to acquire gyro sensor readings before calibration correction.

Protected Attributes

int offset [3]
 Offset values that will be subtracted from output.

Detailed Description

ITG-3200 triple axis digital gyroscope.

Definition at line 87 of file ITG3200.h.

Member Enumeration Documentation

enum Correction

Zero offset correction mode that can be specified when calling getGyroXYZ().

The device has a major drift in readings depending on ambient temperature. You can measure the temperature with built-in thermometer to correct it, but you must have calibration curves for each axes to do so. Here are the options on how to correct the drift.

Enumerator:
NoCorrection 

Do not correct zero offset at all; You would have trouble integrating the values to obtain rotation.

OffsetCorrection 

Correct the outputs with single-point zero adjust.

Calibration 

Use calibration curve (actually lines) to correct the outputs. You must provide coefficients with setCalibrationCurve().

Definition at line 107 of file ITG3200.h.

Constructor & Destructor Documentation

ITG3200 ( PinName  sda,
PinName  scl,
bool  fastmode = false 
)

Constructor.

Sets FS_SEL to 0x03 for proper opertaion.

Parameters:
sda- mbed pin to use for the SDA I2C line.
scl- mbed pin to use for the SCL I2C line.
fastmodeSets the internal I2C interface to use 400kHz clock.

Definition at line 39 of file ITG3200.cpp.

ITG3200 ( I2C &  i2c )

Constructor that accepts external i2c interface object.

Parameters:
i2cThe I2C interface object to use.

Definition at line 130 of file ITG3200.h.

Member Function Documentation

void calibrate ( double  time )

Calibrate the sensor drift by sampling zero offset.

Be sure to keep the sensor stationary while sampling offset.

Once this function is invoked, following getGyroXYZ*() functions return corrected values.

If the drift value changes over time, you can call this function once in a while to follow it. But don't forget to fix the sensor while calibrating!

Parameters:
timeThe time span to sample and average offset. Sampling rate is limited, so giving long time to calibrate will improve correction quality.

Definition at line 297 of file ITG3200.cpp.

int getGyroX ( void   )

Get the output for the x-axis gyroscope.

Typical sensitivity is 14.375 LSB/(degrees/sec).

Returns:
The output on the x-axis in raw ADC counts.

Definition at line 298 of file ITG3200.h.

void getGyroXYZ ( int  readings[3],
Correction  corr = OffsetCorrection 
)

Burst read the outputs on the x,y,z-axis gyroscope.

Typical sensitivity is 14.375 LSB/(degrees/sec).

Parameters:
readingsThe output buffer array that has at least 3 length.
corrCorrection method for returned values.

Definition at line 256 of file ITG3200.cpp.

void getGyroXYZDegrees ( double  readings[3],
Correction  corr = OffsetCorrection 
)

Burst read the outputs on the x,y,z-axis gyroscope and convert them into degrees per second.

Parameters:
readingsThe output buffer array that has at least 3 length.
corrCorrection method for returned values.

Definition at line 515 of file ITG3200.h.

void getGyroXYZRadians ( double  readings[3],
Correction  corr = OffsetCorrection 
)

Burst read the outputs on the x,y,z-axis gyroscope and convert them into degrees per second.

Parameters:
readingsThe output buffer array that has at least 3 length.
corrCorrection method for returned values.

Definition at line 522 of file ITG3200.h.

int getGyroY ( void   )

Get the output for the y-axis gyroscope.

Typical sensitivity is 14.375 LSB/(degrees/sec).

Returns:
The output on the y-axis in raw ADC counts.

Definition at line 307 of file ITG3200.h.

int getGyroZ ( void   )

Get the output on the z-axis gyroscope.

Typical sensitivity is 14.375 LSB/(degrees/sec).

Returns:
The output on the z-axis in raw ADC counts.

Definition at line 316 of file ITG3200.h.

I2C& getI2C (  )

Returns the I2C object that this object is using for communication.

Definition at line 442 of file ITG3200.h.

int getInternalSampleRate ( void   )

Get the internal sample rate.

Returns:
The internal sample rate in kHz - either 1 or 8.

Definition at line 129 of file ITG3200.cpp.

char getInterruptConfiguration ( void   )

Get the interrupt configuration.

See datasheet for register contents details.

7 6 5 4 +------+------+--------------+------------------+ | ACTL | OPEN | LATCH_INT_EN | INT_ANYRD_2CLEAR | +------+------+--------------+------------------+

3 2 1 0 +---+------------+------------+---+ | 0 | ITG_RDY_EN | RAW_RDY_EN | 0 | +---+------------+------------+---+

ACTL Logic level for INT output pin; 1 = active low, 0 = active high. OPEN Drive type for INT output pin; 1 = open drain, 0 = push-pull. LATCH_INT_EN Latch mode; 1 = latch until interrupt is cleared, 0 = 50us pulse. INT_ANYRD_2CLEAR Latch clear method; 1 = any register read, 0 = status register read only. ITG_RDY_EN Enable interrupt when device is ready, (PLL ready after changing clock source). RAW_RDY_EN Enable interrupt when data is available. 0 Bits 1 and 3 of the INT_CFG register should be zero.

Returns:
the contents of the INT_CFG register.

Definition at line 164 of file ITG3200.cpp.

const int* getOffset (  ) const

Returns internal offset values for zero adjusting.

Returned pointer is pointing an array of 3 elements.

Definition at line 449 of file ITG3200.h.

char getPowerManagement ( void   )

Get the power management configuration.

See the datasheet for register contents details.

7 6 5 4 +---------+-------+---------+---------+ | H_RESET | SLEEP | STBY_XG | STBY_YG | +---------+-------+---------+---------+

3 2 1 0 +---------+----------+----------+----------+ | STBY_ZG | CLK_SEL2 | CLK_SEL1 | CLK_SEL0 | +---------+----------+----------+----------+

H_RESET Reset device and internal registers to the power-up-default settings. SLEEP Enable low power sleep mode. STBY_XG Put gyro X in standby mode (1=standby, 0=normal). STBY_YG Put gyro Y in standby mode (1=standby, 0=normal). STBY_ZG Put gyro Z in standby mode (1=standby, 0=normal). CLK_SEL Select device clock source:

CLK_SEL | Clock Source --------+-------------- 0 Internal oscillator 1 PLL with X Gyro reference 2 PLL with Y Gyro reference 3 PLL with Z Gyro reference 4 PLL with external 32.768kHz reference 5 PLL with external 19.2MHz reference 6 Reserved 7 Reserved

Returns:
The contents of the PWR_MGM register.

Definition at line 274 of file ITG3200.cpp.

void getRawGyroXYZ ( int  readings[3] ) [protected]

An internal method to acquire gyro sensor readings before calibration correction.

Protected for the time being, although there could be cases that raw values are appreciated by the user.

Definition at line 243 of file ITG3200.cpp.

int getRawTemperature ( void   )

Get the temperature in raw format.

Returns:
The temperature in raw 16bit integer.

Definition at line 282 of file ITG3200.h.

char getSampleRateDivider ( void   )

Get the sample rate divider.

Returns:
The sample rate divider as a number from 0-255.

Definition at line 106 of file ITG3200.cpp.

float getTemperature ( void   )

Get the temperature of the device.

Returns:
The temperature in degrees celsius.

Definition at line 237 of file ITG3200.cpp.

char getWhoAmI ( void   )

Get the identity of the device.

Returns:
The contents of the Who Am I register which contains the I2C address of the device.

Definition at line 82 of file ITG3200.cpp.

int getWord ( int  regi ) [protected]

Reads a word (2 bytes) from the sensor via I2C bus.

The queried value is assumed big-endian, 2's complement value.

This protected function is added because we shouldn't write getGyroX(), getGyroY() and getGyroZ() independently, but collect common codes.

Parameters:
regiRegister address to be read.

Definition at line 225 of file ITG3200.cpp.

bool isPllReady ( void   )

Check the ITG_RDY bit of the INT_STATUS register.

Returns:
True if the ITG_RDY bit is set, corresponding to PLL ready, false if the ITG_RDY bit is not set, corresponding to PLL not ready.

Definition at line 187 of file ITG3200.cpp.

bool isRawDataReady ( void   )

Check the RAW_DATA_RDY bit of the INT_STATUS register.

Returns:
True if the RAW_DATA_RDY bit is set, corresponding to new data in the sensor registers, false if the RAW_DATA_RDY bit is not set, corresponding to no new data yet in the sensor registers.

Definition at line 206 of file ITG3200.cpp.

void setCalibrationCurve ( const float  offset[3],
const float  slope[3] 
)

Sets calibration curve parameters.

Parameters:
offsetAn array holding calibration curve offsets (0th-order coefficient) for each axis, must have 3 elements.
slopeAn array holding calibration curve slopes (1st-order coefficient) for each axis, must have 3 elements.

Definition at line 71 of file ITG3200.cpp.

void setInterruptConfiguration ( char  config )

Set the interrupt configuration.

See datasheet for configuration byte details.

7 6 5 4 +------+------+--------------+------------------+ | ACTL | OPEN | LATCH_INT_EN | INT_ANYRD_2CLEAR | +------+------+--------------+------------------+

3 2 1 0 +---+------------+------------+---+ | 0 | ITG_RDY_EN | RAW_RDY_EN | 0 | +---+------------+------------+---+

ACTL Logic level for INT output pin; 1 = active low, 0 = active high. OPEN Drive type for INT output pin; 1 = open drain, 0 = push-pull. LATCH_INT_EN Latch mode; 1 = latch until interrupt is cleared, 0 = 50us pulse. INT_ANYRD_2CLEAR Latch clear method; 1 = any register read, 0 = status register read only. ITG_RDY_EN Enable interrupt when device is ready, (PLL ready after changing clock source). RAW_RDY_EN Enable interrupt when data is available. 0 Bits 1 and 3 of the INT_CFG register should be zero.

Parameters:
configConfiguration byte to write to INT_CFG register.

Definition at line 177 of file ITG3200.cpp.

void setLpBandwidth ( char  bandwidth )

Set the low pass filter bandwidth.

Also used to set the internal sample rate. Pass the define bandwidth codes as a parameter.

256Hz -> 8kHz internal sample rate. Everything else -> 1kHz internal rate.

Parameters:
bandwidthLow pass filter bandwidth code

Definition at line 153 of file ITG3200.cpp.

void setPowerManagement ( char  config )

Set power management configuration.

See the datasheet for configuration byte details

7 6 5 4 +---------+-------+---------+---------+ | H_RESET | SLEEP | STBY_XG | STBY_YG | +---------+-------+---------+---------+

3 2 1 0 +---------+----------+----------+----------+ | STBY_ZG | CLK_SEL2 | CLK_SEL1 | CLK_SEL0 | +---------+----------+----------+----------+

H_RESET Reset device and internal registers to the power-up-default settings. SLEEP Enable low power sleep mode. STBY_XG Put gyro X in standby mode (1=standby, 0=normal). STBY_YG Put gyro Y in standby mode (1=standby, 0=normal). STBY_ZG Put gyro Z in standby mode (1=standby, 0=normal). CLK_SEL Select device clock source:

CLK_SEL | Clock Source --------+-------------- 0 Internal oscillator 1 PLL with X Gyro reference 2 PLL with Y Gyro reference 3 PLL with Z Gyro reference 4 PLL with external 32.768kHz reference 5 PLL with external 19.2MHz reference 6 Reserved 7 Reserved

Parameters:
configThe configuration byte to write to the PWR_MGM register.

Definition at line 287 of file ITG3200.cpp.

void setSampleRateDivider ( char  divider )

Set the sample rate divider.

Fsample = Finternal / (divider + 1), where Finternal = 1kHz or 8kHz, as decidied by the DLPF_FS register.

Parameters:
Thesample rate divider as a number from 0-255.

Definition at line 119 of file ITG3200.cpp.

void setWhoAmI ( char  address )

Set the address of the device.

Parameters:
addressThe I2C slave address to write to the Who Am I register on the device.

Definition at line 96 of file ITG3200.cpp.

Field Documentation

const int I2C_ADDRESS = 0xD0 [static]

The I2C address that can be passed directly to i2c object (it's already shifted 1 bit left).

You don't need to manually set or clear the LSB when calling I2C::read() or I2C::write(), the library takes care of it. We just always clear the LSB.

Definition at line 97 of file ITG3200.h.

int offset[3] [protected]

Offset values that will be subtracted from output.

TODO: temperature drift calibration

Definition at line 480 of file ITG3200.h.

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