File content as of revision 2:83a8b7df827f:

/***************************************************************************//**
 * @file SILABS_RHT.h
 * @brief Driver class for the Silicon Labs si70xx series I2C RHT sensors
 *******************************************************************************
 * @section License
 * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
 *******************************************************************************
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 *
 * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
 * obligation to support this Software. Silicon Labs is providing the
 * Software "AS IS", with no express or implied warranties of any kind,
 * including, but not limited to, any implied warranties of merchantability
 * or fitness for any particular purpose or warranties against infringement
 * of any proprietary rights of a third party.
 *
 * Silicon Labs will not be liable for any consequential, incidental, or
 * special damages, or any other relief, or for any claim by any third party,
 * arising from your use of this Software.
 *
 ******************************************************************************/

#ifndef SILABS_RHT_H
#define SILABS_RHT_H

#include "platform.h"
#include <mbed.h>

typedef void (*cbptr_t)(void);

#define SILABS_RHT_ERROR_BUSY		-1
#define SILABS_RHT_ERROR_I2C_BUSY	-2
#define SILABS_RHT_NO_ACTION		-3
#define SILABS_RHT_ERROR_ARGUMENT	-4
#define	SILABS_RHT_OK				0

typedef enum {
	RHT_IDLE,			// Object initialized
	RHT_ACTIVE,			// Object initialized and sensor available
	RHT_MEASURING,		// In the process of getting an RH measurement
	RHT_TEMPERATURE,	// In the process of reading temperature measurement
	RHT_PINGING,		// In the process of polling the device
	RHT_FWREV			// In the process of reading the device's firmware revision
} SILABS_RHT_state_t;

typedef enum {
	si7013,
	si7020,
	si7021
} SILABS_RHT_device_t;

namespace silabs {
class SILABS_RHT {

public:

	SILABS_RHT(I2C * i2c);

	/*
	 * Get last measured temperature data
	 * return: int32_t = temperature in millidegrees centigrade
	 */
	int32_t get_temperature();

	/*
	 * Get last measured relative humidity data
	 * return: uint32_t = relative humidity value in milli-percent
	 */
	uint32_t get_humidity();

	/*
	 * Get current state of the sensor, active or inactive. Need to call check_availability first after initialization.
	 * return: true if the last operation (check_active or measure) was a success, false if not (device did not respond).
	 */
	bool get_active();

	/*
	 * Perform measurement.
	 * Asynchronous callback can be provided (type void (*)(void)).
	 * return: 0 if successful, else one of the defined error codes.
	 */
	int measure(SILABS_RHT_device_t deviceType, cbptr_t callback = NULL);

	/*
	 * Check if the sensor is active and responding. This will update the get_active value.
	 * Asynchronous callback can be provided (type void (*)(void)).
	 * return: 0 if successful, else one of the defined error codes.
	 */
	int check_availability(SILABS_RHT_device_t deviceType, cbptr_t callback = NULL);

protected:
	mbed::I2C *_i2c;

	event_callback_t _internalCallback;
	SILABS_RHT_state_t _state;
	cbptr_t  _completionCallbackPtr;

	uint8_t  _address;
	uint8_t  _rx_buf[8];
	uint8_t  _tx_buf[2];

	uint32_t _rhData;
	int32_t  _tData;



	/**
	 * Callback handler for internal I2C transfers.
	 */
	void _cbHandler( int event );

	/**
	 * Callback handler for internal I2C transfers triggered by timeout.
	 */
	void _cbHandlerTimeout( void );

	/**
	 * Internal lookup table for I2C address by device type.
	 */
	uint8_t get_address(SILABS_RHT_device_t device);
};

} // namespace silabs

#endif //SILABS_RHT_H