API for the HP20X-based Grove Barometer (High-Accuracy) More...

Detailed Description

ID: hp20x
Name: High-accuracy Barometer
Other Names: HP20X Barometer (High-Accuracy)
Category: pressure
Manufacturer: seeed
Link: http://www.seeedstudio.com/depot/Grove-Barometer-HighAccuracy-p-1865.html
Connection: i2c

This is a high-accuracy barometer providing pressure, altitude, and temperature data. It can be calibrated for a given altitude offset, and a wide range of interrupt generating capabilities are supported. As usual, see the HP20X datasheet for more details.

This module was developed using a Grove Barometer (High-Accuracy) based on an HP206C chip.

    // Instantiate an HP20X on default I2C bus and address
    upm::HP20X bar;
    // Initialize the device with default values
    bar.init();
    // Output data every second until interrupted
    while (shouldRun) {
        printf("Temperature: %f Celsius\n", bar.getTemperature());
        printf("Pressure:    %f Millibars\n", bar.getPressure());
        printf("Altitude:    %f Meters\n", bar.getAltitude());
        printf("\n");
        upm_delay(1);
    }

Public Types
enum	HP20X_CMD_T { CMD_SOFT_RST = 0x06, CMD_ADC_CVT = 0x40, CMD_READ_PT = 0x10, CMD_READ_AT = 0x11, CMD_READ_P = 0x30, CMD_READ_A = 0x31, CMD_READ_T = 0x32, CMD_ANA_CAL = 0x28, CMD_READ_REG = 0x80, CMD_WRITE_REG = 0xc0 }

enum	CHNL_BITS_T { CHNL_PT = 0x00, CHNL_T = 0x02, CHNL_SHIFT = 0 }

enum	DSR_BITS_T { DSR_4096 = 0x00, DSR_2048 = 0x01, DSR_1024 = 0x02, DSR_512 = 0x03, DSR_256 = 0x04, DSR_128 = 0x05, DSR_SHIFT = 2 }

enum	HP20X_REG_T { REG_ALT_OFF_LSB = 0x00, REG_ALT_OFF_MSB = 0x01, REG_PA_H_TH_LSB = 0x02, REG_PA_H_TH_MSB = 0x03, REG_PA_M_TH_LSB = 0x04, REG_PA_M_TH_MSB = 0x05, REG_PA_L_TH_LSB = 0x06, REG_PA_L_TH_MSB = 0x07, REG_T_H_TH = 0x08, REG_T_M_TH = 0x09, REG_T_L_TH = 0x0a, REG_INT_EN = 0x0b, REG_INT_CFG = 0x0c, REG_INT_SRC = 0x0d, REG_PARA = 0x0e }

enum	INT_EN_BITS_T { INT_EN_T_WIN_EN = 0x01, INT_EN_PA_WIN_EN = 0x02, INT_EN_T_TRAV_EN = 0x04, INT_EN_PA_TRAV_EN = 0x08, INT_EN_T_RDY_EN = 0x10, INT_EN_PA_RDY_EN = 0x20 }

enum	INT_CFG_BITS_T { INT_CFG_T_WIN_CFG = 0x01, INT_CFG_PA_WIN_CFG = 0x02, INT_CFG_T_TRAV_CFG = 0x04, INT_CFG_PA_TRAV_CFG = 0x08, INT_CFG_T_RDY_CFG = 0x10, INT_CFG_PA_RDY_CFG = 0x20, INT_CFG_PA_MODE = 0x40 }

enum	INT_SRC_BITS_T { INT_SRC_T_WIN = 0x01, INT_SRC_PA_WIN = 0x02, INT_SRC_T_TRAV = 0x04, INT_SRC_PA_TRAV = 0x08, INT_SRC_T_RDY = 0x10, INT_SRC_PA_RDY = 0x20, INT_SRC_DEV_RDY = 0x40, INT_SRC_TH_ERR = 0x80 }

enum	PARA_BITS_T { PARA_CMPS_EN = 0x80 }

Public Member Functions
	HP20X (int bus=HP20X_I2C_BUS, uint8_t address=HP20X_DEFAULT_I2C_ADDR)

	~HP20X ()

bool	init (DSR_BITS_T dsr=DSR_4096)

bool	writeCmd (uint8_t cmd)

bool	writeReg (HP20X_REG_T reg, uint8_t data)

uint8_t	readReg (HP20X_REG_T reg)

int	readData ()

bool	isReady ()

bool	waitforDeviceReady ()

float	getTemperature ()

float	getPressure ()

float	getAltitude ()

void	compensationEnable (bool enable)

bool	setInterruptEnable (uint8_t bits)

bool	setInterruptConfig (uint8_t bits)

uint8_t	getInterruptSource ()

void	setDSR (DSR_BITS_T dsr)

void	recalibrateInternal ()

void	softReset ()

void	setAltitudeOffset (int16_t off)

void	setPAThreshholds (int16_t low, int16_t med, int16_t high)

void	setTemperatureThreshholds (int8_t low, int8_t med, int8_t high)

Protected Attributes
mraa::I2c	m_i2c

Member Enumeration Documentation

enum HP20X_CMD_T

HP20X commands

enum CHNL_BITS_T

CHNL bits

enum DSR_BITS_T

DSR bits

enum HP20X_REG_T

HP20X registers

enum INT_EN_BITS_T

INT_EN bits

enum INT_CFG_BITS_T

INT_CFG bits

enum INT_SRC_BITS_T

INT_SRC bits

enum PARA_BITS_T

PARA bits

Constructor & Destructor Documentation

HP20X	(	int	bus = `HP20X_I2C_BUS`,
		uint8_t	address = `HP20X_DEFAULT_I2C_ADDR`
	)

HP20X constructor

Parameters

bus	I2C bus to use
address	Address for this device

~HP20X ( )

HP20X destructor

Member Function Documentation

bool init ( DSR_BITS_T dsr = DSR_4096 )

Sets up initial values and starts operation

Parameters

dsr	Data sampling rate; one of the DSR_BITS_T values

Returns: True if successful

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bool writeCmd ( uint8_t cmd )

Sends a command to the device

Parameters

cmd	Command to send; usually, one of the HP20X_CMD_T values

Returns: True if successful

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bool writeReg	(	HP20X_REG_T	reg,
		uint8_t	data
	)

Writes a value to a register

Parameters

reg	Register to write to; one of the HP20X_REG_T values
data	Value to write

Returns: True if successful

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uint8_t readReg ( HP20X_REG_T reg )

Reads a register and returns its value

Parameters

reg	Register to read; one of the HP20X_REG_T values

Returns: Value of a specified register

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int readData ( )

Reads 3 bytes of data in response to a conversion request, and converts it to an integer

Returns: Value read back (temperature, pressure, etc.)

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bool isReady ( )

Checks to see if the DR_RDY bit is set, indicating the device can accept commands

Returns: True if the device is ready, false otherwise

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bool waitforDeviceReady ( )

Checks to see if the device is ready, and sleeps/retries if not. Returns once the device indicates it's ready.

Returns: True if the device is ready; false if retries are exhausted

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float getTemperature ( void )

Returns the temperature in Celsius

Returns: Temperature

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float getPressure ( )

Returns the pressure in millibars

Returns: Pressure

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float getAltitude ( )

Returns the computed altitude in meters

Returns: Altitude

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void compensationEnable ( bool enable )

Enables or disables the on-chip compensator. This allows the chip to filter and clean up the output data.

Parameters

enable True to enable, false otherwise

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bool setInterruptEnable ( uint8_t bits )

Sets up the interrupt enable register. This register defines which events can cause a hardware interrupt pin to be pulled high (active).

Parameters

bits	One or more of the INT_EN_BITS_T bits

Returns: True if successful, false otherwise

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bool setInterruptConfig ( uint8_t bits )

Sets up the interrupt configuration register. This register defines which events can cause an interrupt to be indicated.

Parameters

bits	One or more of the INT_EN_BITS_T bits

Returns: True if successful, false otherwise

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uint8_t getInterruptSource ( )

Gets the interrupt source register. This register indicates which interrupts have been triggered. In addition, it indicates when certain operations have been completed.

Returns: One of more of the INT_SRC_BITS_T values

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void setDSR ( DSR_BITS_T dsr )

Sets the data sampling rate. Higher rates are more precise, but take more time per measurement.

Parameters

dsr	One of the DSR_BITS_T values

void recalibrateInternal ( )

Starts an internal recalibration of analog blocks. This is faster than a soft reset.

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void softReset ( )

Executes a soft reset. All register values are reset to power-on defaults. This function returns when the reset is complete and the device reports it is ready.

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void setAltitudeOffset ( int16_t off )

Sets the altitude offset for your region. See the datasheet for more details. Setting this correctly for your region is required for accurate altitude data.

Parameters

off Offset

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void setPAThreshholds	(	int16_t	low,
		int16_t	med,
		int16_t	high
	)

Sets pressure/altitude thresholds for interrupt generation

Parameters

low	Low threshold to generate an interrupt
med	Medium threshold to generate an interrupt
high	High threshold to generate an interrupt

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void setTemperatureThreshholds	(	int8_t	low,
		int8_t	med,
		int8_t	high
	)

Sets temperature thresholds for interrupt generation

Parameters

low	Low threshold to generate an interrupt
med	Medium threshold to generate an interrupt
high	High threshold to generate an interrupt

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

src/hp20x/hp20x.hpp
src/hp20x/hp20x.cxx

Detailed Description

Public Types

Public Member Functions

Protected Attributes

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation