MEMS Sensors - Accelerometer LIS3L06AL

Software Driver for the Accelerometer LIS3L06AL.

This driver relies on the ADC hardware module. It provides functions to initialize the module, to read (x,y,z) coordinates and to get acceleration/orientation/angle information.

Data Structures
struct	avr32_acc_t
	Set of computed data. More...
struct	xyz_t
	All 3-axis values from ADC conversion. More...

Macros
#define	ACC_SHIFT   2

Functions
unsigned long	acc_get_m_x (void)
	Return measured value of X sensor. More...
unsigned long	acc_get_m_y (void)
	Return measured value of Y sensor. More...
unsigned long	acc_get_m_z (void)
	Return measured value of Z sensor. More...
void	acc_init (void)
	Initialize Accelerometer driver. Mandatory to call. More...
void	acc_update (void)
	Get accelerometer measure (3x) and process results. More...
signed long	is_acc_abs_angle_x (unsigned long abs_ang)
	Test if absolute value of X angle has reached the specified limit. More...
signed long	is_acc_abs_angle_y (unsigned long abs_ang)
	Test if absolute value of Y angle has reached the specified limit. More...
bool	is_acc_down (void)
	Test if sensor have detected 'down' orientation. More...
bool	is_acc_left (void)
	Test if sensor have detected 'left' orientation. More...
bool	is_acc_meuh (char stop)
	Detect a topdown to up transition. More...
bool	is_acc_right (void)
	Test if sensor have detected 'right' orientation. More...
bool	is_acc_slow (void)
	Test acceleration about 1g +-10%. More...
bool	is_acc_topdown (void)
	Test if sensor have detected 'topdown' orientation. More...
bool	is_acc_up (void)
	Test if sensor have detected 'up' orientation. More...

Nominal values out of lis3l06al accelerometer spec
#define	ACC_ZERO   (512 >> ACC_SHIFT)
#define	ACC_1G   (205 >> ACC_SHIFT)
#define	ACC_MIN   ( ACC_ZERO - ACC_1G )
#define	ACC_MAX   ( ACC_ZERO + ACC_1G )

Sinus table
#define	SIN0   0
#define	SIN15   0.26
#define	SIN30   0.5
#define	SIN45   0.71
#define	SIN60   0.87
#define	SIN75   0.97
#define	SIN90   1

Axis calibration correction
#define	ACC_CALIB_X   0
#define	ACC_CALIB_Y   0
#define	ACC_CALIB_Z   0

Axis zero point.
#define	ACC_ZERO_X   ( ACC_ZERO + ACC_CALIB_X )
#define	ACC_ZERO_Y   ( ACC_ZERO + ACC_CALIB_Y )
#define	ACC_ZERO_Z   ( ACC_ZERO + ACC_CALIB_Z )

Axis reference values for a set of predefined angles.
#define	ACC_TRIG_X0   (int) ( ACC_ZERO_X - SIN15 * ACC_1G )
#define	ACC_TRIG_X1   (int) ( ACC_ZERO_X + SIN15 * ACC_1G )
#define	ACC_TRIG_Y0   (int) ( ACC_ZERO_Y - SIN15 * ACC_1G )
#define	ACC_TRIG_Y1   (int) ( ACC_ZERO_Y + SIN15 * ACC_1G )
#define	ACC_TRIG_Z_TOP   (int) ( ACC_ZERO_Z - SIN75 * ACC_1G )
#define	ACC_TRIG_Z_BOT   (int) ( ACC_ZERO_Z + SIN60 * ACC_1G )

Sudden acceleration thresholds
#define	ACC_QUIET_LO   (int) ( 0.6 * ACC_1G * ACC_1G )
#define	ACC_QUIET_HI   (int) ( 1.4 * ACC_1G * ACC_1G )

Accelerometer ADC channel mapping
#define	ADC_CHANNEL_X   ADC_ACC_X_CHANNEL
#define	ADC_CHANNEL_Y   ADC_ACC_Y_CHANNEL
#define	ADC_CHANNEL_Z   ADC_ACC_Z_CHANNEL

#define ACC_1G   (205 >> ACC_SHIFT)

Referenced by is_acc_abs_angle_x(), and is_acc_abs_angle_y().

#define ACC_CALIB_X   0

#define ACC_CALIB_Y   0

#define ACC_CALIB_Z   0

#define ACC_MAX   ( ACC_ZERO + ACC_1G )

#define ACC_MIN   ( ACC_ZERO - ACC_1G )

#define ACC_QUIET_HI   (int) ( 1.4 * ACC_1G * ACC_1G )

Referenced by is_acc_slow().

#define ACC_QUIET_LO   (int) ( 0.6 * ACC_1G * ACC_1G )

Referenced by is_acc_slow().

#define ACC_SHIFT   2

Referenced by acc_get_value().

#define ACC_TRIG_X0   (int) ( ACC_ZERO_X - SIN15 * ACC_1G )

#define ACC_TRIG_X1   (int) ( ACC_ZERO_X + SIN15 * ACC_1G )

#define ACC_TRIG_Y0   (int) ( ACC_ZERO_Y - SIN15 * ACC_1G )

#define ACC_TRIG_Y1   (int) ( ACC_ZERO_Y + SIN15 * ACC_1G )

#define ACC_TRIG_Z_BOT   (int) ( ACC_ZERO_Z + SIN60 * ACC_1G )

#define ACC_TRIG_Z_TOP   (int) ( ACC_ZERO_Z - SIN75 * ACC_1G )

#define ACC_ZERO   (512 >> ACC_SHIFT)

#define ACC_ZERO_X   ( ACC_ZERO + ACC_CALIB_X )

Referenced by print_mouse().

#define ACC_ZERO_Y   ( ACC_ZERO + ACC_CALIB_Y )

Referenced by print_mouse().

#define ACC_ZERO_Z   ( ACC_ZERO + ACC_CALIB_Z )

#define ADC_CHANNEL_X   ADC_ACC_X_CHANNEL

Referenced by acc_get_value().

#define ADC_CHANNEL_Y   ADC_ACC_Y_CHANNEL

Referenced by acc_get_value().

#define ADC_CHANNEL_Z   ADC_ACC_Z_CHANNEL

Referenced by acc_get_value().

#define SIN0   0

#define SIN15   0.26

#define SIN30   0.5

#define SIN45   0.71

#define SIN60   0.87

#define SIN75   0.97

#define SIN90   1

unsigned long acc_get_m_x

(

void

)

Return measured value of X sensor.

Returns

measured value of X sensor.

References avr32_acc_t::m, and xyz_t::x.

Referenced by print_mouse().

unsigned long acc_get_m_y

(

void

)

Return measured value of Y sensor.

Returns

measured value of Y sensor.

References avr32_acc_t::m, and xyz_t::y.

Referenced by print_mouse().

unsigned long acc_get_m_z

(

void

)

Return measured value of Z sensor.

Returns

measured value of Z sensor.

References avr32_acc_t::m, and xyz_t::z.

Referenced by print_mouse().

void acc_init

(

void

)

Initialize Accelerometer driver. Mandatory to call.

References adc_configure(), and gpio_enable_module().

Referenced by main().

void acc_update

(

void

)

Get accelerometer measure (3x) and process results.

References acc_get_value(), avr32_acc_t::ag, avr32_acc_t::ak, avr32_acc_t::ak2, avr32_acc_t::g, is_acc_slow(), avr32_acc_t::k, avr32_acc_t::m, avr32_acc_t::s, xyz_t::x, xyz_add(), xyz_diff(), xyz_round0(), xyz_sumsq(), xyz_t::y, and xyz_t::z.

Referenced by main().

signed long is_acc_abs_angle_x

(

unsigned long

abs_ang

)

Test if absolute value of X angle has reached the specified limit.

Returns

bool 1 if limit has been reached in one sens, -1 if limit has been reached in the opposite sens, 0 if limit has not been reached.

References abs, ACC_1G, avr32_acc_t::ak, DEG_2_RAD, and xyz_t::x.

Referenced by print_angles().

signed long is_acc_abs_angle_y

(

unsigned long

abs_ang

)

Test if absolute value of Y angle has reached the specified limit.

Returns

bool 1 if limit has been reached in one sens, -1 if limit has been reached in the opposite sens, 0 if limit has not been reached.

References abs, ACC_1G, avr32_acc_t::ak, DEG_2_RAD, and xyz_t::y.

Referenced by print_angles().

bool is_acc_down

(

void

)

Test if sensor have detected 'down' orientation.

This function uses an software hysteresis.

Returns

bool true if down is detected, false if down is not detected.

References ACC_TRIG_Y1, avr32_acc_t::down, avr32_acc_t::m, avr32_acc_t::pos, and xyz_t::y.

Referenced by print_mouse().

bool is_acc_left

(

void

)

Test if sensor have detected 'left' orientation.

This function uses an software hysteresis.

Returns

bool true if left is detected, false if left is not detected.

References ACC_TRIG_X1, avr32_acc_t::left, avr32_acc_t::m, avr32_acc_t::pos, and xyz_t::x.

Referenced by print_mouse().

bool is_acc_meuh

(

char

stop

)

Detect a topdown to up transition.

This function uses an software hysteresis.

Returns

bool true if topdown to up transition is detected, false if topdown to up transition is not detected.

References ACC_TRIG_Z_BOT, ACC_TRIG_Z_TOP, avr32_acc_t::m, and xyz_t::z.

Referenced by main(), and print_mouse().

bool is_acc_right

(

void

)

Test if sensor have detected 'right' orientation.

This function uses an software hysteresis.

Returns

bool true if right is detected, false if right is not detected.

References ACC_TRIG_X0, avr32_acc_t::m, avr32_acc_t::pos, avr32_acc_t::right, and xyz_t::x.

Referenced by print_mouse().

bool is_acc_slow

(

void

)

Test acceleration about 1g +-10%.

Gravity is always present! This is used to decide slow / fast behavior

Returns

bool true if slow motion is detected, false if fast motion is detected.

References ACC_QUIET_HI, ACC_QUIET_LO, and avr32_acc_t::ak2.

Referenced by acc_update(), and main().

bool is_acc_topdown

(

void

)

Test if sensor have detected 'topdown' orientation.

This function uses an software hysteresis.

Returns

bool true if topdown is detected, false if topdown is not detected.

References ACC_TRIG_Z_BOT, avr32_acc_t::m, avr32_acc_t::pos, avr32_acc_t::topdown, and xyz_t::z.

Referenced by print_mouse().

bool is_acc_up

(

void

)

Test if sensor have detected 'up' orientation.

This function uses an software hysteresis.

Returns

bool true if up is detected, false if up is not detected.

References ACC_TRIG_Y0, avr32_acc_t::m, avr32_acc_t::pos, avr32_acc_t::up, and xyz_t::y.

Referenced by print_mouse().