MMA7660 Class Reference

API for the MMA7660 I2C 3-Axis Digital Accelerometer. More...

Detailed Description

• ID: mma7660
• Name: MMA7660 3-Axis Digital Accelerometer
• Other Names: Grove 3-Axis Digital Accelerometer (1.5g)
• Category: accelerometer
• Manufacturer: seeed
• Connection: i2c gpio

UPM module for the MMA7660 I2C 3-axis digital accelerometer. This device supports a variety of capabilities, including the generation of interrupts for various conditions, tilt and basic gesture detection, and X/Y/Z-axis measurements of g-forces being applied (up to 1.5g)

This module was tested with the Grove 3-Axis Digital Accelerometer (1.5g)

  // Instantiate an MMA7660 on I2C bus 0

  upm::MMA7660 *accel = new upm::MMA7660(MMA7660_DEFAULT_I2C_BUS,
                                         MMA7660_DEFAULT_I2C_ADDR);

  // place device in standby mode so we can write registers
  accel->setModeStandby();

  // enable 64 samples per second
  accel->setSampleRate(MMA7660_AUTOSLEEP_64);

  // place device into active mode
  accel->setModeActive();

  while (shouldRun)
    {
      float ax, ay, az;

      accel->getAcceleration(&ax, &ay, &az);
      cout << "Acceleration: x = " << ax
           << "g y = " << ay
           << "g z = " << az
           << "g" << endl;

      cout << endl;
      usleep(500000);
    }

Public Member Functions
	MMA7660 (int bus, uint8_t address=MMA7660_DEFAULT_I2C_ADDR)
virtual	~MMA7660 ()
bool	writeByte (uint8_t reg, uint8_t byte)
uint8_t	readByte (uint8_t reg)
void	getRawValues (int *x, int *y, int *z)
void	getAcceleration (float *ax, float *ay, float *az)
int	getVerifiedAxis (MMA7660_REG_T axis)
uint8_t	getVerifiedTilt ()
void	setModeActive ()
void	setModeStandby ()
uint8_t	tiltBackFront ()
uint8_t	tiltLandscapePortrait ()
bool	tiltTap ()
bool	tiltShake ()
void	uninstallISR ()
bool	setInterruptBits (uint8_t ibits)
bool	setSampleRate (MMA7660_AUTOSLEEP_T sr)
void	installISR (int pin, void(*isr)(void *), void *arg)

Protected Attributes
mma7660_context	m_mma7660

Constructor & Destructor Documentation

MMA7660	(	int	bus,
		uint8_t	address = MMA7660_DEFAULT_I2C_ADDR
	)

MMA7660 constructor

Parameters

bus	I2C bus to use
address	Address for this sensor; default is 0x55

~MMA7660 ( )

virtual

MMA7660 destructor

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Member Function Documentation

bool writeByte	(	uint8_t	reg,
		uint8_t	byte
	)

Writes a byte value into a register

Parameters

reg	Register location to write into
byte	Byte to write

Returns

True if successful

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uint8_t readByte

(

uint8_t

reg

)

Reads a byte value from a register

Parameters

reg	Register location to read from

Returns

Value in a specified register

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void getRawValues	(	int *	x,
		int *	y,
		int *	z
	)

Reads the current value of conversion

Parameters

x	Returned x value
y	Returned y value
z	Returned z value

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void getAcceleration	(	float *	ax,
		float *	ay,
		float *	az
	)

Gets the computed acceleration

Parameters

ax	Returned computed acceleration of the X-axis
ay	Returned computed acceleration of the Y-axis
az	Returned computed acceleration of the Z-axis

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int getVerifiedAxis

(

MMA7660_REG_T

axis

)

Reads an axis, verifying its validity. The value passed must be one of REG_XOUT, REG_YOUT, or REG_ZOUT.

Parameters

axis	Axis to read

Returns

Axis value

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uint8_t getVerifiedTilt

(

)

Reads the tilt register, verifying its validity

Returns

Tilt value

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void setModeActive

(

)

Puts the device in the active mode. In this mode, register writes are not allowed. Place the device in the standby mode before attempting to write registers.

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void setModeStandby

(

)

Puts the device in the standby (power saving) mode. Note: when in the standby mode, there is no valid data in the registers. In addition, the only way to write a register is to put the device in the standby mode.

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uint8_t tiltBackFront

(

)

Reads tiltBackFront bits

The value returned is one of the MMA7660_TILT_BF_T values

Returns

Bits corresponding to the BackFront tilt status

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uint8_t tiltLandscapePortrait

(

)

Reads tiltLandscapePortrait bits

The value returned is one of the MMA7660_TILT_LP_T values

Returns

Bits corresponding to the LandscapePortrait tilt status

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bool tiltTap

(

)

Reads the tiltTap status

Returns

True if a tap is detected

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bool tiltShake

(

)

Reads the tiltShake status

Returns

True if a shake is detected

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void uninstallISR

(

)

Uninstalls the previously installed ISR

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bool setInterruptBits

(

uint8_t

ibits

)

Enables interrupt generation based on passed interrupt bits. The bits are a bitmask of the requested MMA7660_INTR_T values. Note: the device must be in the standby mode to set this register.

Parameters

ibits

Sets the requested interrupt bits

Returns

True if successful

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bool setSampleRate

(

MMA7660_AUTOSLEEP_T

sr

)

Sets the sampling rate of the sensor. The value supplied must be one of the MMA7660_AUTOSLEEP_T values.

Parameters

sr	One of the MMA7660_AUTOSLEEP_T values

Returns

True if successful

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void installISR	(	int	pin,
		void(*)(void *)	isr,
		void *	arg
	)

Installs an interrupt service routine (ISR) to be called when an interrupt occurs

Parameters

pin	GPIO pin to use as the interrupt pin
fptr	Pointer to a function to be called on interrupt
arg	Pointer to an object to be supplied as an argument to the ISR.

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Collaboration diagram for MMA7660:

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

• /iotdk/jenkins/workspace/upm-doc-stable/src/mma7660/mma7660.hpp
• /iotdk/jenkins/workspace/upm-doc-stable/src/mma7660/mma7660.cxx