MMA8452Q Class Reference

MMA8452Q accelerometer register driver with optional interrupt GPIOs. Initialize the I2C bus before begin(); communication errors are not reported. More...

#include <MMA8452Q.hpp>

Public Types
enum	ODR_t {   ODR_800Hz = 0 , ODR_400Hz = 1 , ODR_200Hz = 2 , ODR_100Hz = 3 ,   ODR_50Hz = 4 , ODR_12p5Hz = 5 , ODR_6p25Hz = 6 , ODR_1p56Hz = 7 }
	Output data rate selections in hertz. More...
enum	Mode_t { MODE_NORMAL = 0 , MODE_LOW_NOISE_LOW_POWER = 1 , MODE_HIGH_RESOLUTION = 2 , MODE_LOW_POWER = 3 }
	Sampling power/noise mode selections. More...

Public Member Functions
void	begin (TwoWire &wire, uint8_t addr, int8_t pinInt1=-1, int8_t pinInt2=-1)
	Bind the bus/address and attach falling-edge interrupt handlers.
uint8_t	readSensorId ()
	Return the WHO_AM_I register byte.
void	readXYZ (int16_t *x, int16_t *y, int16_t *z)
	Read and assemble signed axis register values without conversion to g.
bool	isActive ()
	Return the ACTIVE bit from the control register.
void	setActive ()
	Set the ACTIVE bit to enable measurements.
void	setStandby ()
	Clear the ACTIVE bit to enter standby.
ODR_t	getODR ()
	Return the configured output data rate.
void	setODR (ODR_t val)
	Set the output data rate, temporarily entering standby if needed.
void	onDetectTransient (void(*func)(MMA8452Q &))
	Register the transient interrupt callback; nullptr disables notification.
void	setTransientDetection (bool enableX, bool enableY, bool enableZ, uint16_t thresholdMilliG, uint32_t durationMicros)
	Configure transient detection and restore the previous active state.
void	setMode (Mode_t)
	Write the sampling power/noise mode; put the sensor in standby first.
Mode_t	getMode ()
	Return the configured sampling power/noise mode.

Detailed Description

MMA8452Q accelerometer register driver with optional interrupt GPIOs. Initialize the I2C bus before begin(); communication errors are not reported.

Author

Jongsoo Jeong (CoXlab)

Date

2016. 6. 13.

Examples

nordic-nrf52-dk/MMA8452Q-3-axis/main.cpp.

Member Enumeration Documentation

Mode_t

enum MMA8452Q::Mode_t

Sampling power/noise mode selections.

               {
    MODE_NORMAL = 0,
    MODE_LOW_NOISE_LOW_POWER = 1,
    MODE_HIGH_RESOLUTION = 2,
    MODE_LOW_POWER = 3,
  } Mode_t;

ODR_t

enum MMA8452Q::ODR_t

Output data rate selections in hertz.

               {
    ODR_800Hz = 0,
    ODR_400Hz = 1,
    ODR_200Hz = 2,
    ODR_100Hz = 3,
    ODR_50Hz = 4,
    ODR_12p5Hz = 5,
    ODR_6p25Hz = 6,
    ODR_1p56Hz = 7,
  } ODR_t;

Member Function Documentation

begin()

void MMA8452Q::begin	(	TwoWire &	wire,
		uint8_t	addr,
		int8_t	pinInt1 = -1,
		int8_t	pinInt2 = -1 )

Bind the bus/address and attach falling-edge interrupt handlers.

Parameters

wire	Initialized I2C bus that outlives the driver.
addr	7-bit sensor address.
pinInt1	Optional INT1 GPIO; -1 disables attachment.
pinInt2	Optional INT2 GPIO; -1 disables attachment.

Examples

nordic-nrf52-dk/MMA8452Q-3-axis/main.cpp.

onDetectTransient()

void MMA8452Q::onDetectTransient

(

void(*

func )(MMA8452Q &)

)

Register the transient interrupt callback; nullptr disables notification.

Parameters

func	Receives this driver when a transient interrupt is handled.

readXYZ()

void MMA8452Q::readXYZ	(	int16_t *	x,
		int16_t *	y,
		int16_t *	z )

Read and assemble signed axis register values without conversion to g.

Parameters

x	Optional X output; nullptr skips storing it.
y	Optional Y output; nullptr skips storing it.
z	Optional Z output; nullptr skips storing it. The current implementation combines each high byte shifted by four with the unshifted low byte, then sign-extends bit 11; it does not normalize the low byte.

Examples

nordic-nrf52-dk/MMA8452Q-3-axis/main.cpp.

setODR()

void MMA8452Q::setODR

(

ODR_t

val

)

Set the output data rate, temporarily entering standby if needed.

Parameters

val	Output data rate selection.

Examples

nordic-nrf52-dk/MMA8452Q-3-axis/main.cpp.

setTransientDetection()

void MMA8452Q::setTransientDetection	(	bool	enableX,
		bool	enableY,
		bool	enableZ,
		uint16_t	thresholdMilliG,
		uint32_t	durationMicros )

Configure transient detection and restore the previous active state.

Parameters

enableX	Requested X-axis enable; currently not applied independently (X follows enableZ).
enableY	Enable Y-axis transient detection.
enableZ	Enable Z-axis detection; also controls X in the current implementation.
thresholdMilliG	Threshold in milli-g, clamped to 8000 and quantized in 63 milli-g steps.
durationMicros	Duration in microseconds, clamped and quantized for the current mode/rate.

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The documentation for this class was generated from the following file:

• include/dev/MMA8452Q.hpp