MS5803 Class Reference

UPM API for the MS5803 Pressure and Temperature sensor. More...

Detailed Description

• ID: ms5803
• Name: I2C Barometric Pressure and Temperature Sensor
• Category: temperature pressure
• Manufacturer: sparkfun
• Connection: i2c spi
• Link: https://www.sparkfun.com/products/12909

The MS5803-14BA is a new generation of high resolution pressure sensors with SPI and I2C bus interface. It is optimized for depth measurement systems with a water depth resolution of 1cm and below. The sensor module includes a high linear pressure sensor and an ultra low power 24 bit delta-sigma ADC with internal factory calibrated coefficients. It provides a precise digital 24 bit pressure and temperature value and different operation modes that allow the user to optimize for conversion speed and current consumption. A high resolution temperature output allows the implementation of a depth measurement systems and thermometer function without any additional sensor.

The device is driven at 3.3vdc, and has a pressure range of between 0 and 14 Bar, and a temperature range of between -40 and +85C.

    // Instantiate a MS5803 instance using i2c bus 0 and default address
    upm::MS5803 *sensor = new upm::MS5803(0);

    // For SPI, bus 0, you would pass -1 as the address, and a valid
    // pin for CS (or -1 if you are using a hw pin you have no control
    // over, like edison):
    // MS5803(0, -1, 9);

    while (shouldRun)
    {
        // update our values from the sensor
        sensor->update();

        cout << "Temperature: "
             << sensor->getTemperature()
             << " C, "
             << "Pressure: "
             << sensor->getPressure()
             << " mbar"
             << endl;

        sleep(1);
    }

Public Member Functions
	MS5803 (int bus, int address=MS5803_DEFAULT_I2C_ADDR, int csPin=-1)
	~MS5803 ()
void	reset ()
void	update ()
void	setTemperatureOSR (MS5803_OSR_T osr)
void	setPressureOSR (MS5803_OSR_T osr)
float	getTemperature ()
float	getPressure ()

Protected Member Functions
void	loadCoefficients ()
std::string	busRead (int cmd, int len)
void	busWrite (int cmd, std::string data)

Protected Attributes
ms5803_context	m_ms5803

Constructor & Destructor Documentation

MS5803	(	int	bus,
		int	address = MS5803_DEFAULT_I2C_ADDR,
		int	csPin = -1
	)

MS5803 constructor. The default arguments inititialize I2C operation and the default I2C address.

Parameters

bus	i2c/spi bus to use
address	The address for this device if using I2C. If using SPI, supply -1 for this parameter.
csPin	The GPIO pin to use for Chip Select (CS). This is only needed for SPI, and only if your SPI implementation requires it. Otherwise, just pass -1 if not using SPI, or your CS is handled automatically by your SPI implementation.

~MS5803

(

)

MS5803 Destructor

Member Function Documentation

void reset

(

)

Reset the device.

void update

(

void

)

Take a measurement and store the current sensor values internally. This function must be called prior to retrieving any sensor values, for example getTemperature().

void setTemperatureOSR

(

MS5803_OSR_T

osr

)

Set the output sampling resolution of the temperature measurement. Higher values provide a more precise value. In addition, more precise values require more time to measure. The default set at device intialization is the highest precision supported: MS5803_OSR_4096

Parameters

osr	One of the MS5803_OSR_T values.

void setPressureOSR

(

MS5803_OSR_T

osr

)

Set the output sampling resolution of the pressure measurement. Higher values provide a more precise value. In addition, more precise values require more time to measure. The default set at device intialization is the highest precision supported: MS5803_OSR_4096

Parameters

osr	One of the MS5803_OSR_T values.

float getTemperature

(

void

)

Return the latest measured temperature. update() must have been called prior to calling this function. The returned value is in degrees Celsius.

Returns

Temperature in degrees C

float getPressure

(

)

Return the latest measured pressure. update() must have been called prior to calling this function. The returned value is in millibars.

Returns

Pressure in mbar

void loadCoefficients ( )

protected

Load a series of factory installed compensation coefficients. This function is called during ms5803_init(), so it should never need to be called again. It is provided here anyway "just in case".

Parameters

dev	Device context.

Returns

UPM Status.

string busRead ( int  cmd, int  len  )

protected

Perform a bus read. This function is bus agnostic. It is exposed here for those users wishing to perform their own low level accesses. This is a low level function, and should not be used unless you know what you are doing.

Parameters

cmd	The command or register to access.
cnt	The number of bytes to read.

Returns

The data read

void busWrite ( int  cmd, std::string  data  )

protected

Perform a bus write. This function is bus agnostic. It is exposed here for those users wishing to perform their own low level accesses. This is a low level function, and should not be used unless you know what you are doing.

Parameters

cmd	The command or register to access.
data	The string containing the data to write

Collaboration diagram for MS5803:

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

• src/ms5803/ms5803.hpp
• src/ms5803/ms5803.cxx