Driver for the Freescale MMA8x5x 3-Axis accelerometer. More...

Detailed Description

Driver for the Freescale MMA8x5x 3-Axis accelerometer.

The driver will initialize the accelerometer for best resolution. After the initialization the accelerometer will make measurements at periodic times. The measurements period and scale range can be determined by accelerometer initialization. This driver only implements basic functionality (i.e. no support for external interrupt pins).

This driver provides [S]ensor [A]ctuator [U]ber [L]ayer capabilities.

Modules
	MMA8x5x Accelerometer driver compile configuration

Files
file	mma8x5x.h
	Interface definition for the MMA8x5x accelerometer driver.

file	mma8x5x_params.h
	Default configuration for MMA8x5x devices.

file	mma8x5x_regs.h
	Register definition for the MMA8x5x accelerometer driver.

Data Structures
struct	mma8x5x_params_t
	Configuration parameters. More...

struct	mma8x5x_t
	Device descriptor for MMA8x5x accelerometers. More...

struct	mma8x5x_data_t
	Data type for the result data. More...

Enumerations
enum	{ MMA8X5X_TYPE_MMA8652 = 0x4a , MMA8X5X_TYPE_MMA8653 = 0x5a , MMA8X5X_TYPE_MMA8451 = 0x1a , MMA8X5X_TYPE_MMA8452 = 0x2a , MMA8X5X_TYPE_MMA8453 = 0x3a }
	Devices supported by this driver. More...

enum	{ MMA8X5X_RATE_800HZ = (0 << 3) , MMA8X5X_RATE_400HZ = (1 << 3) , MMA8X5X_RATE_200HZ = (2 << 3) , MMA8X5X_RATE_100HZ = (3 << 3) , MMA8X5X_RATE_50HZ = (4 << 3) , MMA8X5X_RATE_1HZ25 = (5 << 3) , MMA8X5X_RATE_6HZ25 = (6 << 3) , MMA8X5X_RATE_1HZ56 = (7 << 3) }
	Available sampling rates. More...

enum	{ MMA8X5X_RANGE_2G = 0 , MMA8X5X_RANGE_4G = 1 , MMA8X5X_RANGE_8G = 2 }
	Available range options. More...

enum	{ MMA8X5X_OK = 0 , MMA8X5X_DATA_READY = 1 , MMA8X5X_NOI2C = -1 , MMA8X5X_NODEV = -2 , MMA8X5X_NODATA = -3 }
	Named return values. More...

Functions
int	mma8x5x_init (mma8x5x_t dev, const mma8x5x_params_t params)
	Initialize the MMA8x5x accelerometer driver.

void	mma8x5x_set_user_offset (const mma8x5x_t *dev, int8_t x, int8_t y, int8_t z)
	Set user offset correction.

void	mma8x5x_set_active (const mma8x5x_t *dev)
	Set active mode, this enables periodic measurements.

void	mma8x5x_set_standby (const mma8x5x_t *dev)
	Set standby mode.

int	mma8x5x_is_ready (const mma8x5x_t *dev)
	Check for new set of measurement data.

void	mma8x5x_read (const mma8x5x_t dev, mma8x5x_data_t data)
	Read accelerometer's data.

void	mma8x5x_set_motiondetect (const mma8x5x_t *dev, uint8_t int_pin, uint8_t threshold)
	Configure motion detection interrupt.

void	mma8x5x_ack_int (const mma8x5x_t *dev)
	Acknowledge motion detection interrupt.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Devices supported by this driver.

Enumerator
MMA8X5X_TYPE_MMA8652	MMA8652.
MMA8X5X_TYPE_MMA8653	MMA8653.
MMA8X5X_TYPE_MMA8451	MMA8451.
MMA8X5X_TYPE_MMA8452	MMA8452.
MMA8X5X_TYPE_MMA8453	MMA8453.

Definition at line 62 of file mma8x5x.h.

◆ anonymous enum

anonymous enum

Available sampling rates.

Enumerator
MMA8X5X_RATE_800HZ	800 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_400HZ	400 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_200HZ	200 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_100HZ	100 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_50HZ	50 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_1HZ25	12.5 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_6HZ25	6.25 Hz Output Data Rate in WAKE mode
MMA8X5X_RATE_1HZ56	1.56 Hz Output Data Rate in WAKE mode

Definition at line 73 of file mma8x5x.h.

◆ anonymous enum

anonymous enum

Available range options.

Enumerator
MMA8X5X_RANGE_2G	+/- 2 g Full Scale Range
MMA8X5X_RANGE_4G	+/- 4 g Full Scale Range
MMA8X5X_RANGE_8G	+/- 8 g Full Scale Range

Definition at line 87 of file mma8x5x.h.

◆ anonymous enum

anonymous enum

Named return values.

Enumerator
MMA8X5X_OK	everything was fine
MMA8X5X_DATA_READY	new data ready to be read
MMA8X5X_NOI2C	I2C communication failed.
MMA8X5X_NODEV	no MMA8X5X device found on the bus
MMA8X5X_NODATA	no data available

Definition at line 96 of file mma8x5x.h.

Function Documentation

◆ mma8x5x_ack_int()

void mma8x5x_ack_int ( const mma8x5x_t * dev )

Acknowledge motion detection interrupt.

Acknowledges (clears) a motion detection interrupt. See mma8x5x_set_motiondetect().

Warning: : this does incur an I2C write, thus should not be done from within the ISR.

Parameters

[in] dev device descriptor of accelerometer

◆ mma8x5x_init()

int mma8x5x_init	(	mma8x5x_t *	dev,
		const mma8x5x_params_t *	params
	)

Initialize the MMA8x5x accelerometer driver.

Parameters

[out]	dev	device descriptor of accelerometer to initialize
[in]	params	configuration parameters

Returns: MMA8X5X_OK on success; MMA8X5X_NOI2C if initialization of I2C bus failed; MMA8X5X_NODEV if accelerometer test failed

◆ mma8x5x_is_ready()

int mma8x5x_is_ready ( const mma8x5x_t * dev )

Check for new set of measurement data.

Parameters

[in] dev device descriptor of accelerometer

Returns: MMA8X5X_DATA_READY if new sample is ready; MMA8X5X_NODATA if nothing is available

◆ mma8x5x_read()

void mma8x5x_read	(	const mma8x5x_t *	dev,
		mma8x5x_data_t *	data
	)

Read accelerometer's data.

Acceleration will be calculated as:
$a = \frac{value \cdot 1000}{1024} \cdot mg$ if full scale is set to 2g
$a = \frac{value \cdot 1000}{512} \cdot mg$ if full scale is set to 4g
$a = \frac{value \cdot 1000}{256} \cdot mg$ if full scale is set to 8g

Parameters

[in]	dev	device descriptor of accelerometer
[out]	data	the current acceleration data [in mg]

◆ mma8x5x_set_active()

void mma8x5x_set_active ( const mma8x5x_t * dev )

Set active mode, this enables periodic measurements.

Parameters

[out] dev device descriptor of accelerometer to reset

◆ mma8x5x_set_motiondetect()

void mma8x5x_set_motiondetect	(	const mma8x5x_t *	dev,
		uint8_t	int_pin,
		uint8_t	threshold
	)

Configure motion detection interrupt.

User needs to configure MCU side of the selected int pin. mma8x5x will set the pin to low on interrupt. Before another interrupt can occur, the current interrupt must be acknowledged using mma8x5x_ack_int().

Parameters

[in]	dev	device descriptor of accelerometer
[in]	int_pin	select mma8x5x int pin (1 or 2)
[in]	threshold	motion detection threshold (see datasheet)

◆ mma8x5x_set_standby()

void mma8x5x_set_standby ( const mma8x5x_t * dev )

Set standby mode.

Parameters

[in] dev device descriptor of accelerometer

◆ mma8x5x_set_user_offset()

void mma8x5x_set_user_offset	(	const mma8x5x_t *	dev,
		int8_t	x,
		int8_t	y,
		int8_t	z
	)

Set user offset correction.

Offset correction registers will be erased after accelerometer reset.

Parameters

[out]	dev	device descriptor of accelerometer to initialize
[in]	x	offset correction value for x-axis
[in]	y	offset correction value for y-axis
[in]	z	offset correction value for z-axis

Detailed Description

Modules

Files

Data Structures

Enumerations

Functions

Enumeration Type Documentation

◆ anonymous enum

◆ anonymous enum

◆ anonymous enum

◆ anonymous enum

Function Documentation

◆ mma8x5x_ack_int()

◆ mma8x5x_init()

◆ mma8x5x_is_ready()

◆ mma8x5x_read()

◆ mma8x5x_set_active()

◆ mma8x5x_set_motiondetect()

◆ mma8x5x_set_standby()

◆ mma8x5x_set_user_offset()