API for the MPL3115A2 Atmospheric Pressure Sensor. More...

Detailed Description

ID: mpl3115a2
Name: I2C Precision Altimeter
Category: pressure
Manufacturer: freescale
Link: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL3115A2
Connection: i2c

Freescale Semiconductor* MPL3115A2 is a high-precision, ultra-low power consumption pressure sensor. Its operating range is 50-110 kPa.

    float pressure    = 0.0;
    float temperature = 0.0;
    float altitude    = 0.0;
    float sealevel    = 0.0;
    sensor = new upm::MPL3115A2(0, MPL3115A2_I2C_ADDRESS);
    sensor->testSensor();
    while (!doWork) {
        temperature = sensor->getTemperature(true);
        pressure    = sensor->getPressure(false);
        altitude    = sensor->getAltitude();
        sealevel    = sensor->getSealevelPressure();
        std::cout << "pressure value = " <<
                    pressure <<
                    ", altitude value = " <<
                    altitude <<
                    ", sealevel value = " <<
                    sealevel <<
                    ", temperature = " <<
                    temperature << std::endl;
        usleep (500000);
    }

Public Member Functions
	MPL3115A2 (int bus, int devAddr=MPL3115A2_I2C_ADDRESS, uint8_t mode=6)

int	testSensor (void)

int	resetSensor (void)

void	dumpSensor (void)

int	sampleData (void)

int32_t	getPressureReg (int reg)

int32_t	getTempReg (int reg)

float	getPressure (int bSampleData=true)

float	getTemperature (int bSampleData=true)

float	getSealevelPressure (float altitudeMeters=0.0)

float	getAltitude (float sealevelPressure=101325.0)

void	setOversampling (uint8_t oversampling)

uint8_t	getOversampling (void)

float	getTemperatureMax (void)

float	getTemperatureMin (void)

float	getPressureMax (void)

float	getPressureMin (void)

float	convertTempCtoF (float fTemp)

float	convertPaToinHg (float fPressure)

mraa::Result	i2cWriteReg (uint8_t reg, uint8_t value)

uint16_t	i2cReadReg_16 (int reg)

uint8_t	i2cReadReg_8 (int reg)

Constructor & Destructor Documentation

MPL3115A2	(	int	bus,
		int	devAddr = `MPL3115A2_I2C_ADDRESS`,
		uint8_t	mode = `6`
	)

Instantiates an MPL3115A2 object

Parameters

bus	Number of the used bus
devAddr	Address of the used I2C device
mode	MPL3115A2 oversampling (6 = 64x)

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Member Function Documentation

int testSensor ( void )

MPL3115A2 object destructor; basically, it closes the I2C connection. ~MPL3115A2(); no need for this here, as the I2c connection will be closed when the m_i2ControlCtx variable will go out of scope Tests the sensor and tries to determine if the sensor is operating by looking for small variations in the value

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int resetSensor ( void )

Performs a soft reset of the MPL3115A2 device to ensure it is in a known state. This function can be used to reset the min/max temperature and pressure values.

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void dumpSensor ( void )

Dumps out the I2C register block to stdout

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int sampleData ( void )

Initiates a temperature/pressure mesasurement and waits for the function to complete. Temperature and pressure registers can be read after this call.

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int32_t getPressureReg ( int reg )

Reads the pressure value from MPL3115A2 [Pa * 100]

Parameters

reg	Base address of the pressure register

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int32_t getTempReg ( int reg )

Reads the temperature value from MPL3115A2 [degC * 1000]

Parameters

reg	Base address of the temperature register

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float getPressure ( int bSampleData = true )

Reads the current pressure value from MPL3115A2 [Pa]

Parameters

bSampleData Sets non-zero to a sample reading

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float getTemperature ( int bSampleData = true )

Reads the current temperature value from MPL3115A2 [degC]

Parameters

bSampleData Sets non-zero to a sample reading

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float getSealevelPressure ( float altitudeMeters = 0.0 )

Reads the current pressure and, using a known altitude, calculates the sea level pressure value [Pa] This function should be preceded by the sampleData() call

Parameters

altitudeMeters Altitude in meters

float getAltitude ( float sealevelPressure = 101325.0 )

Reads the current pressure and, using a known sea level pressure, calculates the altitude value [m] This function should be preceded by the sampleData() call

Parameters

sealevelPressure Current sea level pressure

void setOversampling ( uint8_t oversampling )

Defines the oversampling setting (ranges from 0 to 7). The value represents 2^n samples (ranging from 1 to 128). The time to calculate a sample is approximately (2^n * 4 + 2) ms

Parameters

oversampling New oversampling value

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