File content as of revision 4:33ee0cf483de:

/**
 ******************************************************************************
 * @file    DevI2C.h
 * @author  AST / EST
 * @version V0.0.1
 * @date    21-January-2015
 * @brief   Header file for a special I2C class DevI2C which provides some
 *          helper function for on-board communication
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *   1. Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *   2. Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *   3. Neither the name of STMicroelectronics nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ******************************************************************************
 */

/* Define to prevent from recursive inclusion --------------------------------*/
#ifndef __DEV_I2C_H
#define __DEV_I2C_H

/* Includes ------------------------------------------------------------------*/
#include "mbed.h"

/* Classes -------------------------------------------------------------------*/
/** Helper class DevI2C providing functions for multi-register I2C communication
 *  common for a series of I2C devices
 */
class DevI2C : public I2C
{
 public:
	/** Create a DevI2C Master interface, connected to the specified pins
	 *
	 *  @param sda I2C data line pin
	 *  @param scl I2C clock line pin
	 */
        DevI2C(PinName sda, PinName scl) : I2C(sda, scl) {}

	/**
	 * @brief  Writes a buffer from the I2C peripheral device.
	 * @param  pBuffer pointer to data to be written.
	 * @param  DeviceAddr specifies the peripheral device slave address.
	 * @param  RegisterAddr specifies the internal address register 
	 *         where to start writing to (must be correctly masked).
	 * @param  NumByteToWrite number of bytes to be written.
	 * @retval 0 if ok, 
	 *         -1 if an I2C error has occured, or
	 *         -2 on temporary buffer overflow (i.e. NumByteToWrite was too high)
	 * @note   On some devices if NumByteToWrite is greater
	 *         than one, the RegisterAddr must be masked correctly!
	 */
	int i2c_write(uint8_t* pBuffer, uint8_t DeviceAddr, uint8_t RegisterAddr, 
		      uint16_t NumByteToWrite)
	{
		int ret;
		uint8_t tmp[TEMP_BUF_SIZE];
	
		if(NumByteToWrite >= TEMP_BUF_SIZE) return -2;
		
		/* First, send device address. Then, send data and STOP condition */
		tmp[0] = RegisterAddr;
		memcpy(tmp+1, pBuffer, NumByteToWrite);

		ret = write(DeviceAddr, (const char*)tmp, NumByteToWrite+1, 0);

		if(ret) return -1;
		return 0;
	}

	/**
	 * @brief  Reads a buffer from the I2C peripheral device.
	 * @param  pBuffer pointer to data to be read.
	 * @param  DaviceAddr specifies the peripheral device slave address.
	 * @param  RegisterAddr specifies the internal address register 
	 *         where to start reading from (must be correctly masked).
	 * @param  NumByteToRead number of bytes to be read.
	 * @retval 0 if ok, -1 if an I2C error has occured
	 * @note   On some devices if NumByteToWrite is greater
	 *         than one, the RegisterAddr must be masked correctly!
	 */
	int i2c_read(uint8_t* pBuffer, uint8_t DeviceAddr, uint8_t RegisterAddr, 
		     uint16_t NumByteToRead)
	{
		int ret;
    
		/* Send device address, with no STOP condition */
		ret = write(DeviceAddr, (const char*)&RegisterAddr, 1, 1);
		if(!ret) {
			/* Read data, with STOP condition  */
			ret = read(DeviceAddr, (char*)pBuffer, NumByteToRead, 0);
		}
    
		if(ret) return -1;
		return 0;
	}

 private:
	static const unsigned int TEMP_BUF_SIZE = 32;
};

#endif /* __DEV_I2C_H */