cmps03.h File Reference

#include <i2c.h>

Go to the source code of this file.

Defines
#define	CMPS03_CALIBRATION_PIN   PIN_A1
	SmartITs standard pin used for calibrating the cmps03.
#define	CMPS03_OVERFLOW   20000
	overflow at value computation
#define	CMPS03_PWM_PIN   PIN_A0
	SmartITs standard pin used for reading the cmps03 pulse width modulation (pwm) values.
Functions
long	get_angle ()
float	get_angle_float ()
long	get_angle_pwm ()
BYTE	get_angle_short ()
BYTE	get_sw_version ()
void	init_i2c_compass ()
void	pin_calibration ()
long	read_bearing ()
BYTE	read_reg1 (BYTE register_number)
long	read_reg2 (BYTE register_number)
void	write_calibration_register ()

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Define Documentation

#define CMPS03_CALIBRATION_PIN   PIN_A1

SmartITs standard pin used for calibrating the cmps03. Definition at line 42 of file cmps03.h. Referenced by pin_calibration().

#define CMPS03_OVERFLOW   20000

overflow at value computation Definition at line 46 of file cmps03.h.

#define CMPS03_PWM_PIN   PIN_A0

SmartITs standard pin used for reading the cmps03 pulse width modulation (pwm) values. Definition at line 37 of file cmps03.h. Referenced by get_angle_pwm().

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Function Documentation

long get_angle (   )

Returns compass angle (compass module cmps03 register 1) as long. Returns: compass module cmps03 register 2 and 3 as one long. Definition at line 246 of file cmps03.h. References init_i2c_compass(), and read_reg2(). Referenced by get_angle_float(), and read_bearing(). { long ret; init_i2c_compass(); ret = read_reg2(2); return (ret); }

float get_angle_float (   )

Returns compass angle (compass module cmps03 register 1) as float. This method internally uses get_angle. Returns: compass module cmps03 register 2 and 3 as one float. Definition at line 258 of file cmps03.h. References get_angle(). { float ret; long temp_angle; temp_angle=get_angle(); ret = ((float)(temp_angle))*0.1; return (ret); }

long get_angle_pwm (   )

Measures the direction using pulse width modulation (pwm). Returns: a counter, a large value means a large angle between north and current heading, 0 means north. Definition at line 86 of file cmps03.h. References CMPS03_PWM_PIN. { long counter; counter=0; // if it's high, wait for a low while(input(CMPS03_PWM_PIN) && (counter<CMPS03_OVERFLOW)) {++counter;} // account for fall time delay_us(1); counter=0; // wait for signal go high while(!input(CMPS03_PWM_PIN) && (counter<CMPS03_OVERFLOW)) {++counter;} counter=0; // wait for signal to go low while(input(CMPS03_PWM_PIN) && (counter<CMPS03_OVERFLOW)) {counter++;} return counter; }

BYTE get_angle_short (   )

Returns compass angle (compass module cmps03 register 1) as BYTE. Returns: compass module cmps03 register 1 as BYTE. Definition at line 235 of file cmps03.h. References init_i2c_compass(), and read_reg1(). { BYTE ret; init_i2c_compass(); ret = read_reg1(1); return (ret); }

BYTE get_sw_version (   )

Reads software version of copass module cmps03. Returns: software version of compass module cmps03. Definition at line 224 of file cmps03.h. References init_i2c_compass(), and read_reg1(). { BYTE ret; init_i2c_compass(); ret = read_reg1(0); return (ret); }

void init_i2c_compass (   )

Initializes the i2c compass module cmps03. Definition at line 105 of file cmps03.h. References I2C_SCL, and I2C_SDA. Referenced by get_angle(), get_angle_short(), and get_sw_version(). { output_float(I2C_SCL); output_float(I2C_SDA); // output_high(CMPS03_CALIBRATION_PIN); }

void pin_calibration (   )

Method used for calibration. Align compass to {north|south|east|west} and call the pin_calibration method. Do this for each direction. make sure the pin state is well defined. to calbrate, drive pin low and release it immediately. Definition at line 137 of file cmps03.h. References CMPS03_CALIBRATION_PIN. { output_high(CMPS03_CALIBRATION_PIN); delay_ms(10); output_low(CMPS03_CALIBRATION_PIN); delay_ms(10); output_high(CMPS03_CALIBRATION_PIN); }

long read_bearing (   )

Function to read bearing. Returns: bearing Definition at line 72 of file cmps03.h. References get_angle(). { long angle; angle = get_angle(); // a value between 0...3599 -> 0 ... 359.9 angle = angle / 10; // divide and lose the 1/10 //bearing = angle; return angle; }

unsigned int read_reg1 (  BYTE  register_number  )

Reads one byte from register regno. Parameters: register_number  register to be read. Returns: byte in register register_number standard i2c bus start sequence. make a read request to address 0xC0 to signal a read from the following register. see i2c protocoll specification (cmps03 handbook). write the register of interest (which is to be read). standard i2c bus stop sequence. standard i2c bus start sequence. make a write request to address 0xC1 to signal a write to the following register. see i2c protocoll specification (cmps03 handbook). read the register of interest (which was written before). a read with param 1 means "ack", a read with param 0 means no ack. standard i2c bus stop sequence. Definition at line 153 of file cmps03.h. Referenced by get_angle_short(), and get_sw_version(). { unsigned int angle; BYTE datal; i2c_start(); i2c_write(0xC0); i2c_write(register_number); // register 2 and 3 i2c_stop(); delay_ms(10); i2c_start(); i2c_write(0xC1); datal=i2c_read(0); //no ack i2c_stop(); angle = (unsigned int) datal; return(angle); }

long read_reg2 (  BYTE  register_number  )

Reads two byte from register regno. Parameters: register_number  register to be read. Returns: long (2 bytes), starting in register register_number standard i2c bus start sequence. make a read request to address 0xC0 to signal a read from the following register. see i2c protocoll specification (cmps03 handbook). write the register of interest (which is to be read). standard i2c bus stop sequence. standard i2c bus start sequence. make a write request to address 0xC1 to signal a write to the following register. see i2c protocoll specification (cmps03 handbook). read the register of interest (which was written before). a read with param 1 means "ack", a read with param 0 means no ack. standard i2c bus stop sequence. Definition at line 188 of file cmps03.h. Referenced by get_angle(). { long angle; BYTE datah,datal; i2c_start(); i2c_write(0xC0); i2c_write(register_number); // register 2 and 3 i2c_stop(); delay_ms(10); i2c_start(); i2c_write(0xC1); datah=i2c_read(1); // ack datal=i2c_read(0); // no ack i2c_stop(); angle = make16(datah, datal); return(angle); }

void write_calibration_register (   )

Used to do calibration, once for north, east, west and south. The sequence is arbitrary. standard i2c bus start sequence. make a write request to address 0xC1 to signal a write to the following register. see i2c protocoll specification (cmps03 handbook). write the register of interest, this time register 15. write the calibration value (255) standard i2c bus stop sequence. Definition at line 116 of file cmps03.h. { i2c_start(); i2c_write(0xC1); i2c_write(0x0F); i2c_write(0xFF); i2c_stop(); delay_ms(11); }

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