Diff: mpl3115a2.h
- Revision:
- 0:b12a7d396be9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/mpl3115a2.h Sun Mar 22 20:55:38 2015 +0000
@@ -0,0 +1,150 @@
+#ifndef __MPL3115A2_H__
+#define __MPL3115A2_H__
+#include <mbed.h>
+
+/// Class to provide simple control of the Freescale MPL311A2 pressure and
+/// temperature sensor. The class allows the user to read the pressure as
+/// barometric, altimeter or raw and the temperature in Celsius.
+///
+/// Reading can be taken either on demand or continuously using either polling
+/// or interrupts to wait for the next reading.
+///
+/// The correct modes should be get before either calling getReadings for
+/// single readings or activate to start continuous readings.
+class MPL3115A2 {
+public:
+ /// Enum for how the pressure data is to be read.
+ enum DataMode {
+ BarometricMode, ///< Barometric presure in Pascals
+ AltimeterMode, ///< Altitude in meters
+ RawMode ///< Raw values from internal DACs
+ };
+
+ /// Enum for how consecutive readings are made
+ enum ReadMode {
+ Single, ///< Make a single reading when calling getReadings, chip remains in standby the rest of the time
+ Polling, ///< Make consecutive readings by polling isDataReady, chip is active all the time.
+ Interupt ///< Make consecutive readings with an interrupt raised when data is ready, chip is active all the time.
+ };
+
+ /// Enum to allow specifying which of the chips two interrupt pins to use.
+ enum InterruptPin {
+ INT1, ///< Pin called INT1 on chip
+ INT2 ///< Pin called INT2 on chip
+ };
+
+ /// Create a new instance of the class using the specified pins for the I2C bus.
+ /// Once initialised the chip is in standby mode.
+ /// @param sda The pin name for the sda line of the I2C bus.
+ /// @param scl The pin name for the scl line of the I2C bus.
+ MPL3115A2(PinName sda, PinName scl);
+
+ /// Read the chip id, this is a fixed value of 0xC4.
+ /// @returns Chip id.
+ int getId(void);
+
+ /// Set the how the pressure is read. The default is BarometricMode if to
+ /// be change then is must be called before getReadings or activate.
+ /// @param mode New mode to read pressure in.
+ void setDataMode(DataMode mode);
+
+ /// Get the current setting for the pressure reading mode.
+ /// @returns Current pressure reading mode.
+ DataMode getDataMode(void);
+
+ /// Set the how get continuous reading. The default is Single if to
+ /// be change then is must be called before getReadings or activate.
+ /// @param mode New continuous reading mode.
+ void setReadMode(ReadMode mode);
+
+ /// Get the current setting for the continuous reading mode.
+ /// @returns Current continuous reading mode.
+ ReadMode getReadMode(void);
+
+ /// Set the number of samples to be used for each reading.
+ /// The number must be a power of two between 1 and 128.
+ /// @param samples Number of samples per reading.
+ void setOverSampling(int samples);
+
+ /// Get the number of samples to be used for each reading.
+ /// @returns Number of samples per reading.
+ int getOverSampling(void);
+
+ /// Sets the number of seconds between consecutive readings.
+ /// The number must be a power of two between 1 and 32768.
+ /// @param period Number of seconds between consecutive readings.
+ void setSamplingPeriod(int period);
+
+ /// Get the number of seconds between consecutive readings.
+ /// @returns Seconds between samples.
+ int getSamplingPeriod(void);
+
+ /// Set which of the chips two interrupt pins should be used to signal
+ /// that the data is ready. It is up to the user to attach the interrupt
+ /// handler to the correct MCU pin and then call either getStatus or
+ /// getReadings within the handler to clear the interrupt.
+ /// @param intPin Chip interrupt pin to signal data ready interrupts.
+ void setDataReadyInt(InterruptPin intPin);
+
+ /// Get the configured interrupt pin used to signal that the data
+ /// is ready.
+ /// @returns Current data ready interrupt pin.
+ InterruptPin getDataReadyInt(void);
+
+ /// Read the chips STATUS register. The register contains data ready and
+ /// overwrite flags.
+ /// @returns Value of the STATUS register.
+ int getStatus(void);
+
+ /// Returns true if there is data available to read.
+ /// @returns True is data is available to read otherwise false.
+ bool isDataReady(void);
+
+ /// Put the chip into active state to allow taking of consecutive
+ /// samples. How often the samples are taken depends on the sampling
+ /// period, the maximum frequency is every one second and the minimum
+ /// every 9 hours.
+ void activate();
+
+ /// Gives the active state of the chip
+ /// @returns True if the chip is in the active state otherwise false.
+ bool isActive();
+
+ /// Puts the chip into the standby state and stops automatic readings.
+ void standby();
+
+ /// Wait for and get the next readings for pressure and temperature.
+ /// If the reading mode is Single then the chip is setup and a wait
+ /// loop entered until the data is available.
+ /// If the reading mode is Polling then the wait loop is entered until
+ /// the next reading is available.
+ /// If the reading mode is Interrupt then the wait loop will exit imediately
+ /// as the data is already available. This will clear the interrupt.
+ /// @param pres Reference to variable to hold the pressure reading in Pascals
+ /// meters depending on the data mode.
+ /// @param temp Reference to variable to hold the temperature reading in
+ /// Celsius.
+ /// @returns True is the reading was sucessful otherwise false. The reading will
+ /// be unsuccessful if the data mode is raw.
+ bool getReadings(float &pres, float &temp);
+
+private:
+ float convTemperature(char *data);
+ float convAltimeter(char *data);
+ float convPressure(char *data);
+
+ void readRegs(char addr, char *data, int len);
+ void writeRegs(const char *data, int len);
+
+private:
+ I2C m_i2c;
+ int m_addr;
+
+ ReadMode m_readMode;
+ DataMode m_dataMode;
+ int m_overSample;
+ int m_samplePeriod;
+ InterruptPin m_dataReadInt;
+};
+
+#endif
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