MPR121 Class Reference

API for the MPR121 I2C Touch Sensor. More...

Detailed Description

• ID: mpr121
• Name: Digital Capacitive Touch Sensor Controller
• Other Names: Grove I2C Touch Sensor
• Category: touch
• Manufacturer: seeed
• Link: http://www.seeedstudio.com/wiki/Grove_-_I2C_Touch_Sensor
• Connection: i2c
• Kit: tsk

UPM module for the MPR121 touch sensor

    // Instantiate an MPR121 on I2C bus 0

    upm::MPR121 touch(MPR121_I2C_BUS, MPR121_DEFAULT_I2C_ADDR);

    // init according to AN3944 defaults
    touch.configAN3944();

    while (shouldRun) {
        touch.readButtons();
        printButtons(touch);
        upm_delay(1);
    }

Public Member Functions
	MPR121 (int bus, uint8_t address=MPR121_DEFAULT_I2C_ADDR)
bool	configAN3944 ()
void	readButtons ()
mraa::Result	writeBytes (uint8_t reg, uint8_t *buffer, int len)
int	readBytes (uint8_t reg, uint8_t *buffer, int len)

Data Fields
uint16_t	m_buttonStates
bool	m_overCurrentFault

Constructor & Destructor Documentation

MPR121	(	int	bus,
		uint8_t	address = MPR121_DEFAULT_I2C_ADDR
	)

MPR121 constructor

Parameters

bus	I2C bus to use

Member Function Documentation

bool configAN3944

(

)

MPR121 destructor ~MPR121(); there is no need for the destructor Sets up a default configuration, based on Application Note 3944 (AN3944): http://cache.freescale.com/files/sensors/doc/app_note/AN3944.pdf

After configuration, the sensor is left in the run state.

Returns

True if configuration is successful

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void readButtons

(

)

Reads button states in the m_buttonStates member variable. Also, sets the m_overCurrentFault variable if overcurrent is detected.

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mraa::Result writeBytes	(	uint8_t	reg,
		uint8_t *	buffer,
		int	len
	)

Writes value(s) into registers

Parameters

reg	Register location to start writing into
buffer	Buffer for data storage
len	Number of bytes to write

Returns

mraa::Result

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int readBytes	(	uint8_t	reg,
		uint8_t *	buffer,
		int	len
	)

Reads value(s) from registers

Parameters

reg	Register location to start reading from
buffer	Buffer for data storage
len	Number of bytes to read

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Field Documentation

uint16_t m_buttonStates

Button states

bool m_overCurrentFault

Overcurrent detected

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

• src/mpr121/mpr121.hpp
• src/mpr121/mpr121.cxx