Functions for Gyrometer ITG3200

Collaboration diagram for Functions for Gyrometer ITG3200:

Functions
int	gyr_write_reg (int i2c_dev, uint8_t reg, uint8_t data)
	WRITE TO REGISTER. More...
uint8_t *	gyr_read_reg (int i2c_dev, uint8_t reg, uint8_t count)
	READ COUNT 8-BIT REGISTER IN SEQUENCE. More...
int	gyr_init (int i2c_dev, float rate, short int lpf_bw, char clk_source, char *act)
	INITIALIZE GYROMETER. More...
int	gyr_read_all_data (int i2c_dev, short int *data)
	READ ALL DATA AT ONCE (X, Y, Z and T) More...
short int	gyr_read_data (int i2c_dev, int type)
	READ DATA (X, Y, Z or T) More...

Detailed Description

Function Documentation

int gyr_init	(	int	i2c_dev,
		float	rate,
		short int	lpf_bw,
		char	clk_source,
		char *	act
	)

INITIALIZE GYROMETER.

Parameters

lpf_bw	(low pass filter bandwidth in Hz) = 256, 188, 98, 42, 20, 10 or 5
rate	(output data rate in Hz) <= 1000 (Fint), if lpf_bw is not 256 <= 8000 (Fint), if lpf_bw is 256 Real rate will be the closest superior rate possible, respcting the formula Rate = Fint/n, 1<=n<=255
clk_source	= 'I' Internal oscillator 'X' PLL with X Gyro reference 'Y' PLL with Y Gyro reference 'Z' Pll with Z Gyro reference Obs: It is highly recommended that the device is configured to use one of the gyros as the clock reference, due to the improved stability
act	(activated gyro data) = "XYZ" All axes are activated "YZ" Only Y and Z axes are activated "XZ" Only X and Z axes are activated "XY" Only X and Y axes are activated "X" Only X axis is activated "Y" Only Y axis is activated "Z" Only Z axis is activated "" Device in very low power sleep mode

Returns

Data of register or NULL in case of any trouble

Definition at line 53 of file gyr_functions.c.

References GYR_DLPF_FS, GYR_PWR_MGM, GYR_SMPLRT_DIV, and gyr_write_reg().

Referenced by devices_init().

{ 
  uint8_t data=0;
  float Fint=1000;

  switch(lpf_bw){
    case 256:
      Fint=8000;
      data=0x18;
      break;
    case 188:
      data=0x19;
      break;
    case 98:
      data=0x1A;
      break;
    case 42:
      data=0x1B;
      break;
    case 20:
      data=0x1C;
      break;
    case 10:
      data=0x1D;
      break;
    case 5:
      data=0x1E;
      break;
    default:
      perror("Wrong low pass filter bandwidth value");
      break;
  }
  
  if(gyr_write_reg(i2c_dev, GYR_DLPF_FS, data)<0){
    perror("Write in Configuration register A unsuccesful");
    return -1;
  }

  if( (rate>Fint)||(rate<0) )
  {
    perror("Wrong choice for rate");
    return -1;
  }
  data=(uint8_t)(Fint/rate - 1);
  
  if(gyr_write_reg(i2c_dev, GYR_SMPLRT_DIV, data)<0){
    perror("Write in configuration register B unsuccesful");
    return -1;
  }
      
  switch(clk_source){
    case 'I':
      data=0x00;
      break;
    case 'X':
      data=0x01;
      break;
    case 'Y':
      data=0x02;
      break;
    case 'Z':
      data=0x03;
      break;
    default:
      perror("Wrong clk_source value");
      break;
  }
      
  if( strcmp(act,"XYZ")==0 );
  else if( strcmp(act,"YZ")==0 )
      data=data|0x20;
  else if( strcmp(act,"")==0 )
      data=data|0x40;
  else if( strcmp(act,"Y")==0 )
      data=data|0x28;
  else if( strcmp(act,"Z")==0 )
      data=data|0x30;
  else if( strcmp(act,"X")==0 )
      data=data|0x18;
  else if( strcmp(act,"XY")==0 )
      data=data|0x08;
  else if( strcmp(act,"XZ")==0 )
      data=data|0x10;
  else{
    perror("Wrong act value in gyrometer initialization");
    return -1;
  }
   
  if(gyr_write_reg(i2c_dev, GYR_PWR_MGM, data)<0){
    perror("Write in mode register unsuccesful");
    return -1;
  }
  
  return 1;
}

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int gyr_read_all_data	(	int	i2c_dev,
		short int *	data
	)

READ ALL DATA AT ONCE (X, Y, Z and T)

Parameters

	i2c_dev
[out]	*data	Vector with all data

Returns

Flag with SUCCESS or FAILURE

Definition at line 149 of file gyr_functions.c.

References FAILURE, gyr_read_reg(), GYR_TEMP_OUT_H, and SUCCESS.

Referenced by read_all_data().

{
  uint8_t i;
  uint8_t *data8;
  union result
  {
    unsigned short int usgnd[4];
    int short sgnd[4];
  } result;
  if( (data8=gyr_read_reg(i2c_dev,GYR_TEMP_OUT_H,8))==NULL)
  {
    //perror("Read accelerometer register failed");
    return FAILURE;
  }
  // Result receives gyro data:
  for(i=1; i<4; i++)
  {
    result.usgnd[i-1]=0;
    result.usgnd[i-1]=result.usgnd[i-1]|((unsigned short int)data8[i*2+1])|(((unsigned int)data8[i*2])<<8);
    data[i-1]=result.sgnd[i-1];
  }
  // Result receives temperature data:
  result.usgnd[3]=0;
  result.usgnd[3]=result.usgnd[3]|((unsigned short int)data8[1])|(((unsigned int)data8[0])<<8);  
  data[3]=result.sgnd[3];
  return SUCCESS;  
}

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short int gyr_read_data	(	int	i2c_dev,
		int	type
	)

READ DATA (X, Y, Z or T)

Parameters

i2c_dev
type	Define kind of read: 'X' or 'Y' or 'Z' or 'T'(temperature)

Returns

Data

Definition at line 177 of file gyr_functions.c.

References GYR_GYRO_XOUT_H, GYR_GYRO_YOUT_H, GYR_GYRO_ZOUT_H, gyr_read_reg(), and GYR_TEMP_OUT_H.

{
  uint8_t *data;
  union result
  {
    unsigned int usgnd;
    int sgnd;
  }result;

  switch(type){
    case 'X':
      data=gyr_read_reg(i2c_dev,GYR_GYRO_XOUT_H,2);
      break;
    case 'Y':
      data=gyr_read_reg(i2c_dev,GYR_GYRO_YOUT_H,2);
      break;
    case 'Z':
      data=gyr_read_reg(i2c_dev,GYR_GYRO_ZOUT_H,2);
      break;
    case 'T':
      data=gyr_read_reg(i2c_dev,GYR_TEMP_OUT_H,2);
    default:
      //perror("Wrong argument for type in gyr_read_data");
      return -1;
  }
  result.usgnd=0;
  result.usgnd=result.usgnd|(((unsigned short int)data[1]))|(((unsigned short int)data[0])<<8);
  return result.sgnd;
}

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uint8_t* gyr_read_reg	(	int	i2c_dev,
		uint8_t	reg,
		uint8_t	count
	)

READ COUNT 8-BIT REGISTER IN SEQUENCE.

Parameters

reg	Register
count	number of registers in sequence

Returns

flag with SUCCESS or FAILURE

Todo:

Verify use of reg parameter

Definition at line 31 of file gyr_functions.c.

Referenced by gyr_read_all_data(), and gyr_read_data().

{
  uint8_t data[9];
  int i;

  //data=(uint8_t*)malloc((count+1)*sizeof(data));
  
  data[0] = reg;

  if (write(i2c_dev, &data, 1) != 1) {           
        //perror("write before read");
        return NULL;
  }
  data[0] = 0;
  if (read(i2c_dev, &data, count) != count) {
        //perror("read");
        return NULL;    
  }

  return data;
}

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int gyr_write_reg	(	int	i2c_dev,
		uint8_t	reg,
		uint8_t	data
	)

WRITE TO REGISTER.

Parameters

i2c_dev
reg	Register
data	Data to write in Register

Author

Caio Gustavo Mesquita Ângelo Rev 0 - 12/11/2012 RLEG project - 2012

Implements the I2C communication between Gumstix Overo Fire and ITG3200

Definition at line 10 of file gyr_functions.c.

References FAILURE, GYR_INT_CFG, GYR_PWR_MGM, GYR_SMPLRT_DIV, GYR_WHO_AM_I, and SUCCESS.

Referenced by gyr_init().

{
  uint8_t reg_data[2];

  reg_data[0] = reg;
  reg_data[1] = data;

  if( !( (reg==GYR_WHO_AM_I)||((GYR_SMPLRT_DIV<=reg)&&(reg<=GYR_INT_CFG))||(reg==GYR_PWR_MGM) ) )
  {
      //perror("Write unsucessful: Not a valid writable register");
      return FAILURE;
  }
        
  if (write(i2c_dev, &reg_data, 2) != 2) {               
          //perror("Write unsuccessful");
          return FAILURE;
  }

  return SUCCESS;
}

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